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1. DE ANGLESTEP MODE BOOLEAN MODE CELSIUS MODE FARENHEIT MODE PCTFULLSCALE MODE PERIODCOUNTER MODE RAW MODE TRANSITIONCNT TYPE ANGLE TYPE CUSTOM TYPE LIGHT ACTIVE TYPE LIGHT INACTIVE TYPE LOWSPEED TYPE LOWSPEED 9V TYPE NO SENSOR TYPE REFLECTION TYPE SOUND DB TYPE SOUND DBA TYPE SWITCH TYPE TEMPERATURE Constructor Summary UltrasonicSensor I2CPort port Method Summary int capture Set capture mode Set the sensor into capture mode int continuous Switch to continuous ping mode int getCalibrationData byte data Return 3 bytes of calibration data byte IgetContinuousInterval Return the interval used in continuous mode int getData int register byte buf int len Executes an I2C read transaction and waits for the result Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 220 int getDistance Return distance to an object int getDistances int dist Return an array of 8 echo distances int getFactoryData byte data Return 10 bytes of factory calibration data byte getMode Returns the current operating mode of the sensor String getUnits Return a string indicating the type of units in use by the unit int off Turn off the senso
2. MODE ANGLESTEP MODE BOOLEAN MODE CELSIUS MODE PCTFULLSCALE MODE PERIODCOUNTER MODE TRANSITIONCNT TYPE ANGLE TYPE CUSTOM TYPE TYPE LIGHT INACTIVE TYPE LOWSPEED TYPE TYPE NO SENSOR TYPE REFLECTION TYPE SOUND DB TYPE SWITCH TYPE TEMPERATURE Constructor Summary Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 228 LightSensor ADSensorPort port Create a light sensor object attached to the specified port LightSensor ADSensorPort port boolean floodlight Create a light sensor object attached to the specified port and sets floodlighting on or off Method Summary void calibrateHigh call this method whtn the light sensor is reading the high value used by reaeValue void calibrateLow call this method when the light sensor is reading the low value used by readValue int getHigh return the normalized value corresponding to readValue 100 int getLow return the normalized value corresponding to readValue 0 int readNormalizedValue Read the current sensor normalized value int readValue Read the current sensor value void setFloodlight boolean floodlight Set floodlighting on or off void setHigh int high set the normalized value corresponding to readValue 100 Daniel Egido S nchez de Vega Section IV Datasheets ROBOT
3. Section II User Manual ROBOT PATROL SYSTEM the operating system In case of doubt check the device manager again You first need to bring the NXT to the firmware upload mode Use a paper clip to ress and hold the hidden button The NXT will then play a soft pulsing sound that signals its readiness Type lejosfirmdl into the command prompt and press enter Lejos requires Libusb to communicate with the NXT If this free software has not yet been installed on your computer it will start the Libusb installation wizard Libusb allows programs to access any USB device on Windows in a generic way Make sure that you do NOT run the test application in the last dialogue In case that LeJOS is already installed on your NXT you will still have to install LibUSB to be able to download your programs You can find it in lejos nxj 3rdparty lib libusb win32 filter bin 0 1 12 1 exe The name may change when a newer version of libusb becomes available JI Campirting ibe LAIA MEMA Some annt ORALE We sene ont AT Once Libusb is installed the Lejos firmware installer will proceed and hopefully complete the process with success It should look like the image below PES Daniel Egido S nchez de V QUSE anie O anchez ae veea LON de i 5 EU 98 Section II User Manual ROBOT PATROL SYSTEM The NXT will now reboot and shortly display the Lejos Logo before changin
4. e printStackTrace break j private void readDummy throws IOException dis readint dis readint dis readint public RobotPatrolSystemListener getListener return listener public void setListener RobotPatrolSystemListener listener this listener listener TERRAM EE EE FEE EE A RA 444 package guiutil rpsa public interface RobotPatrolSystemListener public void patrolStopped public void debug String msg public void isldle boolean idleFlag Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 202 SECTION IV DATASHEETS Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 203 As this project is basically about programming instead of attach datasheets of equipment in this section the main functions of the API of Lego which use the robot will be shown in order to a better understanding of the source code Ref LEJOS 6 Package lejos navigation Navigation classes See Description Interface Summary The Navigator interface contains methods for performing basic Navigator navigational movements The Pilot interface forms a common set of functions an Pilot implementation must offer in order to be used by higher level navigation classes Class Summary The CompassNavigatort class like its superclass can CompassNavigator keep track of the robot position and the direction angle it faces Dan
5. false overcome Retry n i while i 0 amp amp i lt 3 if i gt 2 actuator stop total total overcome get l2 Jelse total int actuator distance j while n lt 4 total lt 300 Sound beepSequence LCD clear LCD drawString dist 0 0 LCD drawint total 6 0 j total distance travelled int get total return total TTT TTT EE import lejos navigation Pilot import lejos nxt public class AB leastX static AB_leastX voyager new AB_leastX static EvasiveBot wayfinder new EvasiveBot static Obstacle obs new Obstacle static Avoid overcome new Avoid static Actuator actuator new Actuator static Sensing sensing new Sensing static UltrasonicSensor us1 new UltrasonicSensor SensorPort S f Daniel Egido S nchez de Vega Qu A Section III Source Code ROBOT PATROL SYSTEM 141 static UltrasonicSensor us2 new UltrasonicSensor SensorPort S2 static UltrasonicSensor us3 new UltrasonicSensor SensorPort S3 Firstly it is assumed the initial robot position as zero and north oriented static int x7 0 initial x position static int y7 0 initial y position lt 25 lt 25 Daniel Egido S nchez de Vega void LeastX int x2 int y2 if x2 gt x7 actuator rotate 90 Jelse if x2 x1 actuator rotate 90 void keepLdistance actuator go actuat
6. AAU VAA U private void startPatrol agent startPatrol Integer parselnt xDest getText Integer parselnt yDest getText btnStart setEnabled false btnStop setEnabled true figs Patrol if public void stopPatrol agent stopPatrol btnStop setEnabled false btnStart setEnabled true public void Connect String connectName cName getText String connectAddress cAddress getText agent connect connectName connectAddress if idleFlag Y btnStart setEnabled true btnStop setEnabled false Daniel Egido S nchez de Vega Section III Source Code ROBOT PATROL SYSTEM 194 else btnStart setEnabled false btnStop setEnabled true j btnConnect setEnabled false btnDisconnect setEnabled true public void Disconnect agent close btnStart setEnabled false btnStop setEnabled false btnConnect setEnabled true btnDisconnect setEnabled false WindowListener C iep public void windowClosing WindowE vent e dispose System exit 0 public void windowOpened WindowE vent e j public void windowActivated WindowEvent e public void windowlconified WindowE vent e public void windowDeiconified WindowEvent e public void windowDeactivated WindowEvent e public void windowClosed WindowEvent e public void actionPerformed ActionEvent event Daniel Egido S nchez de Vega Sectio
7. actuator rotate 180 searching static void searching turn right to search actuator rotate 90 if s readValue gt 50 Hunter Hunting Hunter searching turn left to search actuator rotate 90 if s readValue gt 50 Hunter Hunting Hunter searching actuator stop Hunter lost the prey static void Hunting Daniel Egido Sanchez de Vega Section III Source Code ROBOT PATROL SYSTEM 155 while s readValue gt 50 actuator go if s readValue gt 85 actuator stop Hunter wins Hunter searching public static void main String args Firstly it is supposed the Hunter is always initiated in the corner and oriented Is setFloodlight true actuator rotate 90 Is readValue Is calibrateLow Is setLow 0 actuator rotate 90 Is readValue Is calibrateHigh Is setHigh 100 actuator rotate 180 Hunter Zigzag if s readValue gt 50 Hunter Hunting LINEFOLLOWER 1 Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 156 Follower ETE EH EHEH EEHEHE EHE EE EHE EHE EHE EE A import lejos nxt Motor import lejos nxt SensorPort import lejos nxt SensorConstants public class Follower public static void main String args SensorPort S1 setTypeAndMode SensorConstants TYPE LIGHT ACTIVE SensorConstants MODE PCTFULLSCALE while true
8. true rl true waylength overcome get travel long overcome GoAround waylength rl n Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 120 if overcome get truehole false 88 overcome get r truehole false overcome Return overcome Retry i while i 0 amp amp i lt 3 if i gt 2 pilot stop total total overcome get d Jelse total int pilot getTravelDistance j while n 4 total lt 300 Sound beepSequence LCD clear LCD drawString dist 0 0 LCD drawint total 6 0 Daniel Egido S nchez de Vega Section III Source Code ROBOT PATROL SYSTEM EASYAVOIDANCE Sensing Actuator Obstacle idem Avoid EvasiveBot MM MM M MH H4 Da A ne ee ne De ee import lejos nxt SensorPort import lejos nxt UltrasonicSensor public class Sensing static UltrasonicSensor us new UltrasonicSensor SensorPort S1 int distance UltrasonicSensor us return us getDistance HE import lejos navigation Pilot import lejos nxt Motor public class Actuator static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C wheel diameter trackwidth leftmotor rightmotor void go void back pilot forward Daniel Egido S nchez de Vega 121 Section III Source Code ROBOT PATROL SYSTEM 122 pilot backward int distance return int pilot getT
9. Certainly the hunter strategy could well be to stay very close to the exit point and waiting for the prey approaching but it would not be right and fair so it is not allowed the hunter has to hunts Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 62 Figure 39 Zigzag Hunting Here is shown the scheme of the prowling trajectory to look for the prey It decided use this kind of movement because thought all environment is not covered but the most Thus the hunter has many possibilities to see the prey in any time It is assuming the hunter always starts in a environment s corner and already oriented that is why the perspective of the figure above Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM Figure 40 Zigzag hunting in obstacle avoidance Above it can see a example of hunting with zigzag prowling The blue line marks the original way the robot has to follow and the red line represents the real path travelled by the robot as it has to go on avoiding obstacles Here some incongruities take place For example in the obstacle located most at the left side the robot is surrounding it by the right wall and when finished it has to turn and follow the path by going back by the same way That looks like no sense but it is just a discovered detail about some incompatibility between both behaviors Other matter is when the robot is surrounding a obstacle and before finishing it
10. LCD drawint total 6 0 j total distance travelled int get total return total TTT TTT TTT import lejos navigation Pilot import lejos nxt import java lang Math public class AB STRAIGHT static AB STRAIGHT voyager new AB STRAIGHT static EvasiveBot wayfinder new EvasiveBot static Obstacle obs new Obstacle static Avoid overcome new Avoid Daniel Egido S nchez de Vega DOG Section HI Source Code ROBOT PATROL SYSTEM 132 static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C wheel diameter trackwidth leftmotor rightmotor static UltrasonicSensor us1 new UltrasonicSensor SensorPort S f static UltrasonicSensor us2 new UltrasonicSensor SensorPort S2 static UltrasonicSensor us3 new UltrasonicSensor SensorPort S3 void Orientation int x2 int y2 Firstly it is assumed the initial robot position as zero and north oriented int x1 0 initial x position int y1 0 initial y position int LookAt 0 angle to turn to ahead point B LookAt int Math toDegrees Math atan y2 y1 x2 x1 pilot rotate LookAt j void keepLdistance pilot forward pilot setSpeed 200 while us2 getDistance gt 10 amp amp us3 getDistance lt 25 Motor B setSpeed 210 pilot setSpeed 200 void keepRdistance pilot forward pilot setSpeed 200 while us3 getDistance gt 10 amp amp us3 getDistance lt 25 Motor A se
11. Section HI Source Code ROBOT PATROL SYSTEM 105 EVASIVE ROBOT Obstacle Avoid EvasiveBot TEE EHE EHE EE EHE EHE ERE import lejos navigation import lejos nxt public class Obstacle static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C static UltrasonicSensor us new UltrasonicSensor SensorPort S7 int c 0 obstacles counter int dis 0 distance to obstacle void Closing move close to sensed obstacle C Sound beepSequenceUp do dis us getDistance in cm while dis 5 pilot stop when robot is in 3cm of the obstacle stops int get_dis return dis HE import java lang Math import lejos navigation Pilot import lejos nxt Motor M eod Daniel Egido S nchez de Vega N gt R Section HI Source Code ROBOT PATROL SYSTEM 106 import lejos nxt SensorPort import lejos nxt UltrasonicSensor public class Avoid first try to avoid turning right static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C static UltrasonicSensor us new UltrasonicSensor SensorPort S f static Obstacle obs new Obstacle int deg 0 angle follower static double angle 0 int bound 0 boolean clearway Arue robot can avoid obstacle by the right int s long 0 try to avoid the obstacle by the right boolean TurnRight do deg deg 10 pilot rotate 10 if us getDistance 255 bound us getDistan
12. if MyPosX 6 amp amp MyPosY 9 return true Jelse return false Decreasing one static void Dec_One int var var 1 if var 1 var 1 j gs y A Y Daniel Egido Sanchez de Vega Matos Section HI Source Code ROBOT PATROL SYSTEM 162 checking where is the near wall static int Wa new int 3 1 0 left 1 front 2 right static int NextMove which is the suitable next move static int NearWall 20 distance to near wall public static void main String args while Exit while robot doesnt reach the exit position Walf0 Wal 1 WalT2 0 check which direction is the wall near check left if sensing distance us2 lt NearWall Wall0 1 check front if sensing distance us1 lt NearWall Wall 1 j check right if sensing distance us3 lt NearWall Walf2 1 firstly assuming all ways are unvisited Map MyPosX MyPosY 3 Walf0 Wall 1 Wall 2 NextMove 1 all ways are visited Left of MyDir Right of MyDir RelX MyDir Rel Y MyDin check left path if Wal 0 0 RelX LeftOf RelY LeftOf have we visited the left position Daniel Egido S nchez de Vega E NERA Section HI Source Code ROBOT PATROL SYSTEM 163 if Map MyPosX RelPosX MyPosY NextMove 0 Jelse Dec One Map MyPosX MyPos Y Dec One Map MyPosX RelPos Y 0 RelPosX MyPosY RelPos Y
13. static Actuator actuator new Actuator static Sensing sensing new Sensing static String dist distance static String unit unit int total 0 total straight distance traveled Daniel Egido Sanchez de Vega E Y RY 138 Section HI Source Code ROBOT PATROL SYSTEM 139 void Evasion int i 0 attempts counter int n 0 avoided obstacles counter boolean r clearway true robot can avoid obstacle by the right side boolean clearway true robot can avoid obstacle by the left side int distance 0 distance to left obstacle intr distance 0 distance to right obstacle do actuator counter tachometer reset actuator speed 500 fix speed actuator go if us1 getDistance 255 obs Closing total total int actuator distance do distance sensing distance us2 r distance sensing distance us3 if L distance 255 clearway false Jelse clearway true j if r distance 255 r clearway false Jelse r clearway true j if I clearway true amp amp r clearway true overcome RAround n i 0 if I clearway true amp amp r_clearway false overcome LAround n i 0 if I clearway false amp amp r_clearway true overcome RAround HT Tu Daniel Egido S nchez de Vega Stas a Section II Source Code ROBOT PATROL SYSTEM 140 n i 0 if I clearway false amp amp r clearway
14. LCD drawString Destination 0 0 j Jelse actuator rotate 90 actuator travel d1 actuator rotate 90 actuator travel overcome get l1 d2 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 if overcome get part 4 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 j public static void main String args Firstly it has to provide the destination int x2 150 int y2 150 Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 150 voyager LeastY x2 y2 if y2 y1 if x2 gt x1 actuator rotate 90 do wayfinder Evasion while wayfinder get_total lt x2 Jelse if x2 lt x7 actuator rotate 90 do wayfinder Evasion while wayfinder get_total lt x2 Jelse actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 Jelse if y2 y7 do wayfinder Evasion while wayfinder get total y2 if x2 gt x1 actuator rotate 90 do wayfinder Evasion while wayfinder get_total lt y2 x2 Jelse if x2 lt x1 actuator rotate 90 do wayfinder Evasion while wayfinder get_total lt y2 x2 Jelse actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 if wayfinder get_total x2 y2 if overcome get_part 0 voyager WayCorrec
15. ROBOT PATROL SYSTEM 13 It functions in much the same way as a vehicle differential operates the basic principle being that the motor drives the differential housing via a main drive gear A The differential is geared such that both wheels turn at the same direction and speed B and C This enables smooth transfer of power when a vehicle is turning Both NXT motors drive each wheel directly and are connected to the differential unit via a series of gears such that their directions are inverted When both motors are driving the same speed the differential unit will remain stationary If the motors are not in sync the differential will turn for the duration that the motors are not in sync it provides a means to monitor when motors are driving at different speeds When they are driving in sync the differential will remain stationary Using Casters to Go Straight Casters are another key factor in getting the differential drive moving and turning smoothly Usually they are not given enough consideration Unfortunately its design is limiting and it will skid orjam It uses two wheels coupled on the same axle and doesn t allow the wheels to turn independently In the assembly on the left the axle turns with the wheel whereas the one on the right has the wheels spinning on the axle Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 14 Figure 3 Coupled caster Ref DAMG07 Figure 4 Caster to a
16. j j check front path if Walii 0 RelX MyDir RelY MyDir have we visited the left position if Map MyPosX RelPosX MyPosY RelPos Y 0 NextMove 1 Jelse Dec One Map MyPosX MyPos Y Dec One Map MyPosX RelPosX MyPosY RelPosY j check right path if Wal 2 0 RelX RightOf RelY RightOf nave we visited the left position if Map MyPosX RelPosX MyPosY NextMove 2 Jelse Dec One Map MyPosX MyPos Y Dec One Map MyPosX RelPos Y 0 RelPosX MyPosY RelPos Y j j switch NextMove case 0 go left actuator Left Left of MyDir Gi 7 Daniel Egido Sanchez de Vega x M Section HI Source Code ROBOT PATROL SYSTEM 164 MyDir LeftOf break case 2 go right actuator Right Right of MyDir MyDir RightOf break if NextMove 1 Should we move forward actuator Travel MyPath PathCounter NextMove RelX MyDir MyPosX RelPosx RelY MyDir MyPosY RelPosY continue actuator back while Map MyPosxX MyPos Y lt 2 amp amp PathCounter gt 0 switch MyPath PathCounter case 0 go back right actuator Right Right of MyDir MyDir RightOf break case 2 go back left actuator Left Left of MyDir MyDir LeftOf break actuator Travel RelX MyDir RelY MyDir change position MyPosX RelPosX MyPosY RelPosY j j actuator stop
17. j j Poka i EK 4 Daniel Egido Sanchez de Vega ES AS Section HI Source Code ROBOT PATROL SYSTEM 165 INTERFACE RPS NXT RPSSystem Constants O O O Event Protocol State Localizer Encoder Localizer Data O O O O EncoderData Range SonarData TrueFalse Utilities O 0000000 0 O Current Position Direction Calculator Detection Range Timer Control Coordinator Sonar Sensor Speaker Actuator RPS Server RPS Server Listener HE EEE EEE Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 166 import Localizer Localizer import rpss utilities CurrPosition import rpss utilities RP Coordinator import rpss data EncoderData import selab rpss RobotPatrolSystemServer import selab rpss RobotPatrolSystemServerListener public class RPSSystem implements RobotPatrolSystemServerListener private RobotPatrolSystemServer server null private RPCoordinator RPC private CurrPosition CP private EncoderData ED private Localizer LT public RPSSystem server new RobotPatrolSystemServer server setListener this CP new CurrPosition ED new EncoderData LT new Localizer CP server ED RPC new RPCoordinator LT server CP public void start server startServer RPC RPC timer start public void startPatrol int x int y server debug start Patrol x x y y RPC startPatrol x y
18. Restores things to the default state Following this call the sensor will be operating in continuous mode Returns 0 if ok 0 otherwise Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 225 9 11 getFactoryData public int getFactoryData byte data Return 10 bytes of factory calibration data The bytes are as follows data 0 Factory zero call data 1 Factory scale factor cal2 data 2 Factory scale divisor Returns 0 if ok 0 otherwise 9 12 getUnits public String getUnits Return a string indicating the type of units in use by the unit The default response is 10E 2m indicating centimetres in use Returns 7 byte string 9 13 getCalibrationData public int getCalibrationData byte data Return 3 bytes of calibration data The bytes are as follows data 0 zero cal1 data 1 scale factor cal2 data 2 scale divisor Returns 0 if ok 0 otherwise 9 14 setCalibrationData public int setCalibrationData byte data Set 3 bytes of calibration data The bytes are as follows data 0 zero Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 226 call data 1 scale factor cal2 data 2 scale divisor This does not currently seem to work Returns 0 if ok 0 otherwise 9 15 getContinuousInterval public byte getContinuousInterval Return the interval used in continuous mode This seems to be in the range
19. THE LEAST X THE LEAST Y This algorithm is just a modification of the previous one It keeps the background about obstacle avoidance travelling straight but instead of going directly to the target in some environments could be more appropriated to take another different strategy Of course as always mentioned the obstacles must be well oriented j x Figure 35 Example of AB LeastX algorithm Daniel Egido S nchez de Vega 56 Section I Report ROBOT PATROL SYSTEM Above it can see how the robot firstly travels towards the minimum X coordinate that is instead of going to the final coordinates X Y at time it divides the process in two steps first try to accomplish one coordinate and later the other one When the robot is located in the Y coordinate axle then it starts to get the Y coordinate which lead it to the destination Figure 36 Optimal way The approach is not leading to the optimal path but in this case is quite similar almost the best one as it can see in the figure the green line could be the optimal way as the other ways are actually closed because the Daniel Egido S nchez de Vega 57 Section I Report ROBOT PATROL SYSTEM width robot is big enough for not passing through the holes and spaces among obstacles Of course it is obvious in this type of environment it check that the previous algorithm AB straight cannot be applied because the obstacles involved in th
20. YES DESTINATION else action Event NO DESTINATION j else if action Event STOP 1 action Event STOPPED YESINTRUSION PT timer stop LT timer stop WA Stop Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 182 else if action Event STOP 2 action Event STOPPED_NOINTRUSION_NODEPARTED PT timer stop LT timer stop WA Stop else if action Event STOP_3 action Event STOPPED_NOINTRUTION_YESDESTINATION PT timer stop LT timer stop WA Stop else if action Event UPDATE_RANGE M action Event UPDATED RANGE PR updateRange else if action Event ALARM action Event ALARMED SPK Beep else if action Event PATROL_STOPPED action Event EMPTY else if action Event GET_DIRECTION action Event DIRECTION direction DC getDirection R start_x R start_y R end_x R end_y direction 190 public void startPatrol int p int q X y 9 stopFlag false action Event START PATROL j public void stopPatrol stopFlag true Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM public void timedOut synchronized syncObj coordinate PE SIR ARAL SL A RR A E A de dr package rpss utilities import rpss data SonarData import lejos nxt SensorPort import lejos nxt UltrasonicSensor public class SonarSensor pri
21. if SensorPort S7 readValue gt 50 Motor A setSpeed 75 Motor C setSpeed 0 Jelse Motor A setSpeed 0 Motor C setSpeed 75 Daniel Egido S nchez de Vega RUE M Section HI Source Code ROBOT PATROL SYSTEM 157 Follower ETE EH EHEHE EHE HE EHE EHE EE D EE EHE RE RH import lejos nxt public class Follower public static void main String aArg throws Exception String left Left String right Right LightSensor light new LightSensor SensorPort S3 final int blackWhiteThreshold 45 final int forward 1 final int stop 3 final int flt 4 final int power 80 Use the light sensor as a reflection sensor light setFloodlight true LCD drawString Light 96 0 0 Show light percent until LEFT is pressed while Button LEFT isPressed LCD drawint light read Value 3 9 0 LCD refresh j Follow b style color black background color ffff66 gt line lt b gt until ESCAPE is pressed while Button ESCAPE isPressed if light readValue gt blackWhiteThreshold On white turn right LCD drawString right 0 1 MotorPort B controlMotor 0 stop MotorPort C controlMotor power forward else On black turn left LCD drawString left 0 1 Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 158 MotorPort B controlMotor power forward MotorPort C controlMotor 0 stop j LCD drawin
22. negative the left wheel is on the outside 7 19 steer void steer int turnRate int angle Moves the NXT robot in a circular path at a specific turn rate The center of the turning circle is on the right side of the robot if parameter turnRate is negative Values for turnRate are between 200 and 200 The turnRate determines the ratio of Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 213 inner wheel speed to outer wheel speed as a percent Formula ratio 100 abs turnRate When the ratio is negative the outer and inner wheels rotate in opposite directions Examples e steer 25 gt inner wheel turns at 75 of the speed of the outer wheel e steer 100 gt inner wheel stops e steer 200 gt means that the inner wheel turns at the same speed as the outer wheel a zero radius turn Note Even if you have specified a drift correction in the constructor it will not be applied in this method Parameters turnRate If positive the left wheel is on the inside of the turn If negative the left wheel is on the outside angle The angle through which the robot will rotate If negative robot traces the turning circle backwards 7 20 steer void steer int turnRate int angle boolean immediateReturn Moves the NXT robot in a circular path at a specific turn rate The center of the turning circle is on the right side of the robot if parameter turnRate is negative Value
23. order to be accepted and approachable u Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 47 b425 cos 90 h NB b Ec 4 Hole s width resulting But as already mentioned before this technique only can work in so specific conditions which could not be made successfully That is why it has to think of other option to put in practice Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 48 Easy Avoidance After some considerations it concluded that best way would be to omit these calculations and to simplify considerably the algorithm so the robot performs just deciding one way and trying to surround the obstacle over there if not possible it change to the other direction Firstly it tries to surround by right side and later by left After turning if there is no front obstacle it moves forward and checks the wall each certain distance 40 cm predefined This way may seem too simple especially compared with the last one and lacking of emotion but unfortunately with the available resources there is no other way to obstacle avoidance in efficient way Figure 30 Robot facing an obstacle Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 49 The last algorithm tried to get the best way in terms of space that is travelled distance forgetting the time spend in that task In this more practical algorithm take the opposite approach by
24. to the main menu tm a Your NXT is now ready to run Java programs 5 3 4 Install and configure Eclipse on your Computer Download Eclipse IDE for Java Developers Eclipse itself is written in Java and does not contain an installer setup exe It comes in a simple ZIP file that ou should unzip into the previously created ProgramFiles directory You may want to create a shortcut to eclipse exe on your desktop for your own convenience When you start Eclipse you will be asked to choose a workspace The workspace will contain all the files that you create Again you should create a directory in a location so that the path does not contain any space characters now In our example we use the directory d programming workspace You will then be greeted with the welcome screen We will now create a Hello World program and upload others call it download it into the NXT First you need to create a new Java Daniel Egido S nchez de Vega Section II User Manual ROBOT PATROL SYSTEM project Click on File gt New gt Java Project Give the project a new name but avoid space characters We called ours LeJOS NXJ Next you need to turn this project into a Lejos project Right click onto the roject and select Properties Select Java Build Path on the left and click on the Libraries tab Afterwards click on Add External JARs and locate the lib
25. 1 15 It can be read and set However tests seem to show it has no effect Others have reported that this does vary the ping interval when used in other implementations Please report any new results Returns if error otherwise the interval 9 16 setContinuousInterval public int setContinuousInterval byte interval Set the ping inetrval used when in continuous mode See getContinuouslnterval for more details Returns 0 if Ok lt gt 0 otherwise 9 17 getMode public byte getMode Returns the current operating mode of the sensor 0 sensor is off 1 Single shot ping mode 2 continuous ping mode default 3 Event capture mode Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM Returns if error otherwise the operating mode 10 lejos nxt Class LightSensor java lang Object L lejos nxt LightSensor All Implemented Interfaces SensorConstants public class LightSensor extends Object implements SensorConstants Abstraction for a NXT light sensor The light sensor can be calibrated to low and high values WARNING THIS CLASS IS SHARED BETWEEN THE classes AND pccomms PROJECTS DO NOT EDIT THE VERSION IN pccomms AS IT WILL BE OVERWRITTEN WHEN THE PROJECT IS BUILT Field Summary Fields inherited from interface lejos nxt SensorConstants
26. 2 Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 143 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 if overcome get part 3 actuator counter while sensing distance us2 lt 25 voyager keepLdistance d1 actuator distance actuator rotate 90 actuator counter while sensing distance us2 25 voyager keepLdistance d2 actuator distance if d2 gt overcome get l1 actuator rotate 90 actuator counter while sensing distance us2 25 voyager keepLdistance d3 actuator distance if d3 gt 2 d1 actuator stop LCD clear LCD drawString no way 0 0 Jelse actuator rotate 90 actuator travel d2 overcome get 11 actuator rotate 90 actuator travel d1 d3 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 Jelse actuator rotate 90 actuator travel d1 actuator rotate 90 Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 144 actuator travel overcome get l1 d2 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 if overcome get part 4 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 public static void main String args Firstly it has to provide the destination i
27. Next connect the NXT to the computer with the USB cable Check the correct installation of the driver by checking the device manager Right click on My Computer and select Properties Switch to the hardware tab Click on Device manager It should list Lego Devices gt Lego Mindstorms NXT 5 2 3 Install Lejos on your Computer and on your Mindstorms NXT Download Lejos At the time this tutorial was created version Beta 0 4 was the latest release By now newer versions are available and we cannot guarantee that this tutorial will work for the newer versions Daniel Egido S nchez de Vega 95 Section II User Manual ROBOT PATROL SYSTEM 96 Create a directory called ProgramFiles on your hard disk The already existing directory Program Files does contain a space character between Program and Files that sometimes causes problems in the usage of Java technology You will later also install Eclipse into the ProgramFiles directory Unzip the Lejos ZIP file This will reveal a directory called lejos nxj Place it in your ProgramFiles directory We now need to inform Java of the existence of the Lejos library Right click on My Computer and select Properties Click on the Advanced tab Click on Environment Variables at the bottom Create a new System variable by clicking on New at the bottom Do NOT create a User variable at the top Name the new system variable LEJOS HO
28. State IDLE return Event PATROL STOPPED else if event Event STOPPED_NOINTRUTION_YESDESTINATION Daniel Egido Sanchez de Vega Section II Source Code ROBOT PATROL SYSTEM 178 state State UPDATING RANGE return Event UPDATE RANGE j else if state State ALARMING if event Event ALARMED state State IDLE return Event PATROL STOPPED j else if state State UPDATING RANGE if event Event UPDATED RANGE state State CALCULATING DIRECTION return Event GET DIRECTION return event THEE LO A A ERAE2Mec package rpss utilities import Constants Event import Constants State import Localizer Localizer import rpss data Range import rpss data SonarData import rpss data TrueFalse import selab rpss RobotPatrolSystemServer import lejos util Timer import lejos util TimerListener ee RPCoordinator coordinate events and actions using variable action returned from RobotPatrolControl that has parameter event public class RPCoordinator implements TimerListener private RobotPatrolSystemServer server public Timer timer 2 new Timer 20 this Daniel Egido S nchez de Vega Section III Source Code ROBOT PATROL SYSTEM 179 public TrueFalse timerElapsedflag For recognizing PatrolTimer fired private Object syncObj new Object Monitor used for coordinate private int x y private int action temp action
29. actuator distance if d3 gt 2 d1 actuator stop LCD clear LCD drawString no way 0 0 Jelse actuator rotate 90 actuator travel d2 overcome get 11 actuator rotate 90 actuator travel d1 d3 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 Jelse actuator rotate 90 actuator travel d1 actuator rotate 90 actuator travel overcome get l1 d2 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 y j j if overcome get part 2 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 j if overcome get part 3 actuator counter while sensing distance us2 lt 25 voyager keepLdistance d1 actuator distance actuator rotate 90 actuator counter while sensing distance us2 25 voyager keepLdistance Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 149 d2 actuator distance if d2 gt overcome get I actuator rotate 90 actuator counter while sensing distance us2 25 voyager keepLdistance d3 actuator distance if d3 gt 2 d1 actuator stop LCD clear LCD drawString no way 0 0 Jelse actuator rotate 90 actuator travel d2 overcome get 11 actuator rotate 90 actuator travel d1 d3 actuator stop Sound beepSequence LCD clear
30. actuator rotate 90 void RAround actuator rotate 90 actuator counter do actuator go part 1 while sensing distance us2 255 l1 actuator distance actuator rotate 90 actuator counter while sensing distance us2 255 actuator go part 2 12 actuator distance actuator rotate 90 actuator travel l1 actuator rotate 90 void LAround actuator rotate 90 actuator counter do actuator go part 3 while sensing distance us3 255 l1 actuator distance actuator rotate 90 actuator counter actuator go while sensing distance us3 255 actuator go part 4 12 actuator distance actuator rotate 90 actuator travel 1 Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM actuator rotate 90 int get 1 return 1 int get_12 return 1 int get d return d int get_part return part HE import lejos navigation Pilot import lejos nxt public class EvasiveBot static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C wheel diameter trackwidth leftmotor rightmotor static UltrasonicSensor us new UltrasonicSensor SensorPort S7 static UltrasonicSensor us2 new UltrasonicSensor SensorPort S2 static UltrasonicSensor us3 new UltrasonicSensor SensorPort S3 static Obstacle obs new Obstacle static Avoid overcome new Avoid
31. and Y coordinates where it must introduce the specific number in order to get the robot in some different position it will calculate later the direction that it must taken to get there It is also included a kind of serial number actually that is the address of the robot for the Bluetooth connection embedded in the NXT This data is found in the information about the NXT in the brick Finally there are four buttons Connect Disconnect Patrol and Stop for the different options Firslty it press the connection button F 4 i A TE Daniel Egido S nchez de Vega META a 85 Section I Report ROBOT PATROL SYSTEM 86 and continuing by selecting patrol then the robot stars with the programmed and corresponding application In this case the behavior is not so much relevant as what it wish to check is the good performance of the interface so in the example practiced the robot only go to the ordered coordinates and come back and it repeats this motion until finding an obstacle in its trayectory then it just stops The experiments obtained good results after some problems in the Bluetooth connection which can became an annoying difficulty Next some interface example with different coordinates are shown ves rae 0 Q LHS OF ay Or ES 8 Java E Hierarchy C3 D Obstacle java Jj PathFinder java D UserinterfaceSubS 52 8 O g og EE B E package gui la E a y AB leastX
32. black wall in hunting behavior Figure 43 Lego Robot in front of the black wall Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 68 Line Follower As mentioned this application has been developed mainly because it is a unavoidable example in robotics projects not because of his level of difficulty and anyway is another kind of environment where the robot has to manage by trying to accomplish an objective so it considers suitable for this project To build the environment it has used as usual white and black hard paper The circuit is not quite complicated just following the regular ones but adding some close curves with right angles in order to check if the robot can follow it with a good performance Figure 44 LineFollower circuit Daniel Egido S nchez de Vega a s R Section I Report ROBOT PATROL SYSTEM p Figure 45 Right angled curve It could program this application in many different ways depending on the approach available sources or the sophistication it desires to get For example it had been much better to have disposition of two or more light sensors Thus the robot could follow the line faster without reducing the efficacy But it disposes of one light sensor and according to that it has developed two different programs in practice quite similar anyway The first one is the simplest possible taking as limit the mean value of the light sensor it acts movin
33. ilt i 4 7 UU DO ES Java H8 Package Explorer 23 Hierarchy O 3 Obstacle java jj PathFinder java m UserlnterfaceSubS 52 s 033 gt B ES package gui ES 13 AB leastX a E a 1 import guiutil rpsa RobotPatrolSystemAgent RLO amp amp LineFollower 1 E we LineFollower 2 E impo t pruebaavo2 TX amp pruebaAVo3 gy 8 6 Userl B E pruebaevi Daniel Egido oF 4 e pruebalabe 1e RPS NXT i ls RPX GUI public class UserInterfaceSubSystem extends JFrame implements Windo ou B S sre n E B gui x D VESTES Res NXT Coninfo Name DANIMAS E guiutil gulutil rpsa x 50 Y ko m JRE System Library jre1 6 0 02 Ds Bo a ka o anaes Address 001553020093 el 5 jtools jar ai pecomm jar ac pctools jar mt E lib gt eE TREMAUX SOLVER Disconnection mt mc private boolean idleFlag true w ag a m J a km el Problems Javadoc Declaration El Console 52 m X X 6028 15 05 UserlnterfaceSubSystem Java Application C Program FilestWJavatfjre1 6 0 O2wWbintfjavaw exe 2009 05 27 2 9 35 40 P 3 Java Userinterta Figure 58 Interface with different coordinates NXT Coninfo Name DANIMAS X 50 Y so Address 001853028094 ous re NXT Coninfo Name DANIMAS K 0 Ti v 60 Address 001653028032 Figure 59 Interfaces with different coordinates Daniel Egido S nchez de Vega Section I Report RO
34. long Jelse rl false waylength overcome get travel long j overcome GoAround waylength rl n Jelse rl false waylength overcome get travel long overcome GoAround waylength rl n if I clearway false amp amp r_clearway true if overcome get truehole true overcome Analyze if overcome get_r_last_bound lt overcome get_ _last_bound rl true waylength overcome get_r_travel_long Jelse rl false waylength overcome get travel long j overcome GoAround waylength rl n Jelse Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 119 rl true waylength overcome get travel long overcome GoAround waylength rl n if I clearway false amp amp r clearway if overcome get truehole true amp amp overcome get r truehole true false overcome Analyze if overcome get_r_last_bound lt overcome get_ _last_bound rl true waylength overcome get_r_travel_long Jelse rl false waylength overcome get travel long overcome GoAround waylength rl n if overcome get truehole true amp amp overcome get r truehole false rl false waylength overcome get travel long overcome GoAround waylength rl n if overcome get truehole false amp amp overcome get r truehole
35. private boolean stopFlag false private int direction private int currentpositionX currentpositionY private int currentDistance private DirectionCalculator DC private IntrusionDetector ID private PatrolRange PR private PatrolTimer PT private Localizer LT private RobotPatrolControl RPC private SonarSensor SS private Speaker SPK private WheelActuator WA private CurrPosition CP private Range R private SonarData SD public RPCoordinator Localizer LT_ RobotPatrolSystemServer USR CurrPosition CP_ server USR For debug CP CP timerElapsedflag new TrueFalse timerElapsedflag flag false action Event EMPTY Els EI DC new DirectionCalculator ID new IntrusionDetector R new Range PR new PatrolRange R PT new PatrolTimer timerElapsedflag RPC new RobotPatrolControl Daniel Egido Sanchez de Vega Section II Source Code ROBOT PATROL SYSTEM 180 SD new SonarData SS new SonarSensor SD SPK new Speaker WA new WheelActuator private void coordinate if RPC state State IDLE server isldle true else server isldle false if timerElapsedflag flag amp amp RPC state State MOVING timerElapsedflag flag false action Event AFTER ELAPEDTIME if stopFlag amp amp RPC state State MOVING RPC state State READING SENSOR RPC state State CHECKING INTRUSION RPC state State CHEC
36. resultMsg Protocol PROTOCOL RESULTOK result true else if resultMsg Protocol PROTOCOL RESULTERROR result false j catch Exception e e printStackTrace j return result j private void writeDummy throws IOException dos writelnt Protocol PROTOCOL DUMMY dos writelnt Protocol PROTOCOL DUMMY dos writelnt Protocol PROTOCOL DUMMY public void run while isRunning int resultMsg Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 200 try readDummy resultMsg dis readint if resultMsg Protocol PROTOCOL RESULTOK queue add new Integer resultMsg else if resultMsg Protocol PROTOCOL_RESULTERROR queue add new Integer resultMsg else if resultMsg Protocol PROTOCOL PATROLSTOPPED if listener null listener patrolStopped this close else if resultMsg Protocol PROTOCOL_DEBUG if listener null int length dis readInt char msgChars new char length for int i20 i msgChars length i msgChars i dis readChar listener debug new String msgChars else if resultMsg Protocol PROTOCOL ISIDLE if listener null boolean idleFlag dis readBoolean Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 201 listener isldle idleFlag catch EOFException e catch IOException e
37. rotate forward Overrides forward in class BasicMotor 11 10 backward public void backward Causes motor to rotate backwards Overrides backward in class BasicMotor 11 11 reverseDirection public void reverseDirection Reverses direction of the motor It only has effect if the motor is moving Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 239 Overrides reverseDirection in class BasicMotor 11 12 flt public void flt Causes motor to float The motor will lose all power but this is not the same as stopping Use this method if you don t want your robot to trip in abrupt turns Overrides flt in class BasicMotor 11 13 stop public void stop Causes motor to stop pretty much instantaneously In other words the motor doesn t just stop it will resist any further motion Cancels any rotate orders in progress Overrides stop in class BasicMotor 11 14 lock public void lock int power Applies power to hold motor in current position Use if stop is not good enough to hold the motor in positiOn against a load Parameters power a value between 1 and 100 Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 240 11 15 isMoving public boolean isMoving Description copied from class BasicMotor Returns true iff the motor is in motion Overrides isMoving in class BasicMotor Returns true iff the motor is cu
38. routes have been left unexplored This occurs when it comes firstly to a four way junction It will take the right path leaving the other two for the future Daniel Egido S nchez de Vega 76 Section I Report ROBOT PATROL SYSTEM 77 We really need to use this method to remember the value of the cells as for instance when the robot finds itself in a dead end it needs to backtrack through its own path until the robot reachs a position in which an unexplored path was left Figure 51 Maze solver dealing with a dead path For an easier backtracking procedure it marks these positions on the map with a value of 2 or 3 making it faster to go back to these The current position in Map is stored in two variables MyPosX and MyPosY int Map SIZE X SIZE Y int MyPosX IO MyPosY i int MyPath SIZE X SIZE Y int PathCounter 0 It defines two more useful macros that return a relative map position at a particular direction Daniel Egido S nchez de Vega La s V Section I Report ROBOT PATROL SYSTEM 78 static void RelX int dir l if dir West RelPosX 1 Jelse if dir East RelPosX 1 lelse RelPosX 0 j j static void RelY int dir if dir North RelPosY 1 Jelse if dir South RelPosY 1 lelse RelPosY 0 j Now it can find out what is around robot in the maze map The current position is Map MyPosX MyPosY In front of the robot is Map
39. sacrificing the optimal way for avoiding the obstacle in the least time possible that is performing always non stopping for calculations only checking sometimes the wall in order to find the limit of the obstacle and the earliest time to turn and go on Figure 31 Lego Robot travelling straight towards an obstacle Daniel Egido S nchez de Vega EN E Section I Report ROBOT PATROL SYSTEM The experiments carried out resulted successfully Afterwards it stepped forward by adding two more ultrasonic sensors to the robot Easy Avoidance algorithm was modified to perform with three ultrasonic sensors one frontal and two sides placed In this conditions obviously the performing is better faster the robot surrounds the obstacles without turning to check the wall as the side sensor is already doing continuously Nevertheless the same problem persists It unknowns the theoretical and exact distance to which the sensor is limited for detection as based on the experiments it seems dependable of the obstacle s surface Due to that the robot may find some tricky environments in which there are two side obstacles too apart from the front obstacle of course and one of them is closer but it exists a hole to pass and the other one is further but is connected with the front obstacle so there is no space to surround Then the robot was lead to wrong way trying to avoid by further wall detected and the other would be unconsidered
40. so it takes into account implicitly that is assuming the bending corner in the next explanations Taking the successful trials it proceeds to explain the calculations carried out in this technique Knowing the distance to the obstacle and registering the angle in which the bound is detected it can determine the distance to the bound by simple trigonometry Daniel Egido S nchez de Vega 38 Section I Report ROBOT PATROL SYSTEM 39 Figure 23 Distance to bound calculation 5 cos x Ec 1 Distance to corner equation After determining the direct distance to obstacle s corner it uses that data to get the distance the robot would have to travel parallel to the wall in order to avoid the obstacle Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 40 Figure 24 Calculating distance to travel d h cos B Ec 2 Distance to travel equation To result a proper distance to travel it has to consider a couple of things The difference of measuring that means in the figure 24 it can appreciate that when the robot is sensing the bound that is not the same position that when the robot is parallel to the wall preparing to avoid it It is because the sensor is not located in the center of the robot but in the Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM front face Anyway this is a small distance that could be omitted if involved in good conditi
41. such as excavators tanks Employing an additional set of tracks at the front it can pivot to provide additional navigation functionality Each track is powered by its independent motor The advantage of a skid steer drive is its capability to turn on the spot which allows vehicles of this Daniel Egido S nchez de Vega E zi x 16 Section I Report ROBOT PATROL SYSTEM type to operate in tight areas The downside to this is that when it is turning it appears a considerable quantity of friction on surfaces such as carpets If you are running rubber tracks in that sense it also get a extra coefficient for climbing capability Figure 7 A tracked Skid Steer Drive Ref DAMG07 In a wheeled skid steer drive may be necessary to include some characteristic It should transmit the power to all the wheels because otherwise probably it will not turn softly or even anything In the next example it is connected by a common chain drive for each side receiving power from two motors such as is shown in the tracked style This platform performs with quite strength and it is also fast compact and even light Daniel Egido S nchez de Vega E WERT wy 17 Section I Report ROBOT PATROL SYSTEM 18 Figure 8 Wheeled Skid Steer Drive Ref DAMG07 Skid steer drives have some common characteristics with differential drives for example they both have the same difficulties in going exactly straight However this arc
42. the internet that these robots from LEGO are not only a enjoying entertainment as technological hobby but also a really useful and versatile educational tool The show is a great quantity of schools high schools and universities that is at all levels that use this kind of tool included as could have been guessed the lab in which this project has been developed to teach some technologic courses to the students That is why this project has been executed with this tool Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 2 Motivation In the personal perspective as in the technological view this Project is considered very interesting Actually any task related to robotics underlies a look to future Some of the algorithms answer to standard robot behavior for competitions so in this case is more like a leaning and put in practice than a selling purpose and other ones are focus on a navigation a little closer to reality so having many kind of applications In the commercial sense a robot provided with a navigation system enabled to avoid obstacles and reach the target place could be requested for many tasks For example a robot which is working in a department store in charge of providing help to customers is called for somebody from anywhere Then the robot has to go to that place where its help is requested by avoiding walls furniture people and it has to know the direction to get there As th
43. the way to travel yf LL A Daniel Egido Sanchez de Vega AS Section III Source Code ROBOT PATROL SYSTEM 117 int distance 0 intr distance 0 distance to left obstacle distance to right obstacle int total 0 total straight distance traveled boolean rl true right shortcut false left shortcut do pilot resetTachoCount tachometer reset pilot setSpeed 500 fix speed pilot forward if us1 getDistance 255 obs Closing total total int pilot getTravelDistance do distance us2 getDistance r_distance us3 getDistance if _distance 255 clearway false Jelse clearway true j if r distance 255 r clearway false Jelse r clearway true overcome TurnRight overcome TurnLeft overcome Return if I clearway true amp amp r clearway true overcome Analyze if overcome get_r_last_bound overcome get last bound overcome get r travel long overcome get travel long rl false Daniel Egido Sanchez de Vega rl true waylength Jelse rl false waylength overcome GoAround waylength n if I clearway true amp amp r_clearway Section HI Source Code ROBOT PATROL SYSTEM 118 if overcome get r truehole true overcome Analyze if overcome get_r_last_bound lt overcome get_ _last_bound rl true waylength overcome get r travel
44. this project On the one hand it is about the informatics tool used to program the applications and tasks developed and the alternatives which it could have also worked with In this case it has considered several options Eclipse Lego Mindstorm Matlab and Labview On the other hand it explains the developed algorithms their selves and the diverse possibilities conceived In this sense the algorithms can be classified as already mentioned before in two groups those are too sophisticated to put in practice into the Lego robot and those simpler and suitable for practice and trials Always it keeps clear that all process must be carried out in JAVA object oriented programming language as one of the preview conditions of this project Actually regarding the possible tools the only true option is Eclipse workspace as the project must be developed in JAVA So in the section of User Manual a installation guide is included Daniel Egido S nchez de Vega 26 Section I Report ROBOT PATROL SYSTEM ALGORITHMS In this subsection it explains the algorithms that have been conceived and programmed Firstly it has approached some methods for obstacle avoidance regarded as the main goal in the project development and divided in according to complexity or resources availability as it can be sensors Among them such as Evasive Robot tracking from A point to B point the chosen one Easy Avoidance Robot to be implemented in the rob
45. to program the navigation system in JAVA thus the first step implies to invest a certain and considerable time in learning this programming language and consequently to be introduced in the world of Object Oriented Programming for first time After making a study about the structural possibilities it continues with the analysis of the options to manage the environments and chosen challenges Subsequently it develops the appropriate algorithms taking into account the alternatives and the technology which it is working In the next sections it talks about the technology which it is going to work with and it mentions the motivation and objectives of the project and some preview considerations Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 1 Study of the existing technologies and projects As for the robot navigation this is the first contact with this aspect of field of robotics which is a very important subject as it is requested in so many applications because independently of the function or objective of any robot it must know to cope with the environment in which is carrying out its tasks But regarding the technology is being used in this project is from LEGO MINDSTORMS specifically the new so called NXT technology developed by this company directed to improve the characteristics and possibilities of its products for the fans of robotics It is not difficult to find out by surfing a little
46. ways not tried hold path traveled static int MyPath new int SizeX Size Y Daniel Egido S nchez de Vega EN Section HI Source Code ROBOT PATROL SYSTEM 160 start position static int MyPosX 6 static int MyPosY 0 static int PathCounter 0 static void Left of int dir LeftOf dir 1 4 static void Right_of int dir if dir North RightOf East Jelse RightOF 1 j Convert directions to relative positions in map static void RelX int dir if dir West RelPosX 1 yelse if dir East RelPosX 1 Jelse RelPosX 0 j j static void RelY int dir if dir North RelPosY 1 Jelse if dir South RelPosY 1 Jelse RelPosY 0 j j Current Position Map MyPosX MyPosY currently in front of us Daniel Egido Sanchez de Vega x 4 Section HI Source Code ROBOT PATROL SYSTEM 161 Map MyPosX RelPosX MyDir MyPosY RelPosY MyDir current right Map MyPosX RelPosX RightOf MyDir MyPosY RelPosY RightOf MyDir current left Map MyPosX RelPosX LeftOf MyDir MyPosY RelPosY LeftOf MyDir Initialize map static void InitialMap boundaries and inside maze int i 0 int j 0 for i 0 i lt SizeX i Maplil 0 Map i SizeY 1 1 for j 0 j lt Size Y j Map 0l j Map SizeX 1 j 1 for i 1 i lt SizeX 1 i for j 1 j lt SizeY 1 j Mapli j Maplil j 0 static boolean Exit
47. 0 if wayfinder get_total Math sqrt Math pow x2 2 Math pow y2 2 if overcome get_part 0 voyager WayCorrection if overcome get_part 0 pilot stop Sound beepSequence LCD clear LCD drawString Destination 0 0 Daniel Egido Sanchez de Vega Section III Source Code ROBOT PATROL SYSTEM 136 AB THE LEAST X Sensing idem Actuator idem Obstacle idem Avoid EvasiveBot AB LeastX ETE EH EE HC EHE EE HE EE EE HE EHE REPE EP HER import lejos navigation Pilot import lejos nxt Motor import lejos nxt SensorPort import lejos nxt UltrasonicSensor public class Avoid static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C static UltrasonicSensor us1 new UltrasonicSensor SensorPort S1 static UltrasonicSensor us2 new UltrasonicSensor SensorPort S2 static UltrasonicSensor us3 new UltrasonicSensor SensorPort S3 static Obstacle obs new Obstacle static Avoid overcome new Avoid static Actuator actuator new Actuator static Sensing sensing new Sensing static int d 0 distance traveled int part 0 ko identify the obstacle s stretch int l1 0 int l2 0 backwards void Retry while us1 getDistance obs dis 5 pilot backward y ou Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 137 j pilot stop Turn back Repositioning void Return
48. 5 getSpeed public int getSpeed Returns the current motor speed in degrees per second 11 26 getMode public int getMode Description copied from class BasicMotor Returns the mode Overrides getMode in class BasicMotor Returns 1 forward 2 backward 3 stop 4 float 11 27 getPower public int getPower Description copied from class BasicMotor Returns the current power setting Overrides getPower in class BasicMotor Returns power value 0 100 Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 244 11 28 getLimitAngle public int getLimitAngle Return the angle that a Motor is rotating to Returns angle in degrees 11 29 isRotating public boolean isRotating returns true when motor rotation task is not yet complete a specified angle 11 30 isRegulating public boolean isRegulating 11 31 getActualSpeed public int getActualSpeed returns actualSpeed degrees per second calculated every 100 ms negative value means motor is rotating backward 11 32 getTachoCount public int getTachoCount Returns the tachometer count Returns tachometer count in degrees Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 11 33 resetTachoCount public void resetTachoCount Resets the tachometer count to zero 11 34 getError public float getError for debugging Returns regulator error 11 35 getBasePower publ
49. Access to NXT sensors motors etc See Description Interface Summary ADSensorPort BasicMotorPort BasicSensorPort ButtonListener I2CPort LegacySensorPort ListenerCaller SensorConstants SensorPortListener Tachometer An abstraction for a port that supports Analog Digital sensors An abstraction for a motor port that supports RCX type motors but not NXT motors with tachometers An abstraction for a sensor port that supports setting and retrieving types and modes of sensors Abstraction for receiver of button events Abstraction for a port that supports I2C sensors Abstraction for a port that supports legacy RCX sensors Interface for calling calling lejos listeners Constants used to set Sensor types and modes Interface for monitoring changes to the value for an Analogue Digital sensor such as a Touch Light or Sound sensor on a SensorPort Abstraction for the tachometer built into NXT motors Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 217 Abstraction for a motor port that supports NXT TachoMotorPort motors with tachometers Class Summary An abstraction for a motor without a tachometer BasicMotor such as an RCX motor Battery Provides access to Battery Button Abstraction for an NXT button Flash Read and write access to flash memory in pages Abstract class that implements common methods for I2CSensor all I2C sensors LCD Text and grap
50. BOT PATROL SYSTEM CHAPTER 4 CONCLUSIONS As for the final judgment about this project it must underline that it has resulted to be a worthy and interesting challenge in which it has been able to deal with real problems in the robotics works such as navigation and positioning and to deep a little into this amazing field Despite the emerged troubles and resources limitations it has developed a varied whole of navigation applications where it shows the capacity of the patrol robot to manage different environments in which it must accomplish diverse objectives and goals through common and alternative ways In the first stages it could not follow the planned schedule as should but slowly it was reaching a better rhythm of working Moreover the lately resources availability and the slow process of JAVA learning caused an unbalanced performance during some time But once set the basis and having understood the main concepts not only about programming but also the different approaching for the algorithms and robot behavior then it carried out a longer more efficient process until the last stage Daniel Egido S nchez de Vega 88 Section I Report ROBOT PATROL SYSTEM Due to that the trials could not be carried out before the last phase the efficacy of the algorithms was not checked until then consequently some methods were demonstrated not to have a good enough performance so it had to correct and modify even in some case t
51. EM There is an important matter not considered so far How can the robots recognize each other without confusing with the obstacles Well as the robot s surface is very clear quite white a good option is to use black obstacles and a light sensor to differentiate the obstacles and the other robot In addition if there were available two light sensors it could improve the source code to able the hunter to detect what way the prey has taken in his escape so the reaction of the hunter would be much better and it could do a more efficient hunting Then in this application the robot has got three ultrasonic sensors and one light sensor so it is using all connectors However it unknowns the range of the light sensor in official data as such information is not provided Anyway in case of short range the most possible there would not a great problem because both robots would have the same problem Hunter needs to be close to detect the prey and the last one the same for avoiding and escaping from the hunter Moreover the environment is not so large so there has to be enough percentage for both to get victory In the next figures it shows the Lego Robot with the mentioned black obstacle to make sense what has been explained But in the figures the robot is just posing without the light and side ultrasonic sensors Daniel Egido S nchez de Vega 66 Section I Report ROBOT PATROL SYSTEM 67 Figure 42 Lego Robot facing a
52. Finally the robot would not find the way so would think that there is no way possible thus the robot would go backwards in order to try again from further distance This robot confusion would not take place in the previous algorithm as the robot would be able to detect and estimate the hole But as it is not a feasible algorithm it has to accept the simple one Daniel Egido Sanchez de Vega 50 Section I Report ROBOT PATROL SYSTEM STRAIGHT FROM A TO B The next algorithm is based on the previous one taking it as background for accomplish the objective in this application The robot has to departure from a place that always is called A point It has to direct towards the finishing place so called B point Of course there could be many different ways to get there always avoiding obstacles of course but it decided to reuse the previous Easy Avoidance algorithm to face this challenge so the robot goes always straightforward avoiding obstacles until arriving the final point The robot is given a coordinates about the point where it must get and then it calculates the suitable turn for the correct direction after that it moves straight In this case it can find the same problem that previously for example if the robot is travelling with 45 deviation the obstacles have to be right angled respect to the facing robot If it is going with 30 would have to happen the same and so forth Then due to this proble
53. Follower 1 S E LineFollower 2 qui la pruebaavo2 oe PO x ptt amp Userl ES pruebaAVO3 Daniel Egido df te pruebaevi si ij ii pruebalabe 7 9 s 122 RPS NXT New a e RPX GUI ceSubSystem extends JFrame implements lindo o l H Ba ate Open F3 RobotPatrolSystemListener o l i 8 gui Open With n l eD SSNMENACESUBSYStE Open Type Hierarchy F4 n 4 rr long serialVersionUID 1L a E bee en E Copy Cic ystem gent agent 3 uiutil i T i 2 mi JRE System Library irel 6 0 E Bu ERES CU eare Suo 0 bluecove jar 8 Paste is rid ub amp classes jar XX Delete Delete Connect e l mu 1 isconnect md E D el Build Path 2 A nuclear Source AltsShiftsS gt lenaaress mo g lib Refactor Alt Shift T gt fDest S E TREMAUX SOLVER SH Bento Sd 14 Export Flag true a v It References T gt dall a Declarations 5 EE onsole 53 Ex BB rt B F3 Oo gt Refresh F5 ation C Program FilesWJavatfjre1 6 0 O2WbintYjavaw exe 2009 05 27 235 9 33 34 Run As gt 5 1Java Application Alt Shift x J Debug As Team O Run Compare With Replace With n gui UserlnterfaceSubSyste Restore from Local History PASO l E Java Userinterta Properties Alt Enter QELLON 92235 Figure 56 Running interface application When done it appears in the screen a small window that is the interface and it contains some information The name the X
54. KING DESTINATION RPC state State L OCALIZING stopFlag false action Event STOP PATROL j if action Event AVOID TIMER action temp action return if action Event SETTING action Event DIRECTION PR setRange x y CP setCurrPosition 0 direction DC getDirection 0 0 x y server debug x x y y server debug Direction direction j else if action Event TURN DIRECTION Daniel Egido S nchez de Vega Section III Source Code ROBOT PATROL SYSTEM 181 action Event TURNED WA Rotate direction j else if action Event START action Event STARTED WA Forward else if action Event STARTING action Event EMPTY PT timer start LT timer start Departed message is needed else if action Event READ SENSORDATA action Event SENSORDATA SS readSonarData else if action Event CHECK_INTRUSION if ID checklntrusion SD getDistance action Event YES INTRUSTION else action Event NO INTRUSION else if action Event GET_CURRPOSITION action Event CURRPOSITOIN currentpositionX CP getCurrPositionX currentpositionY CP getCurrPositionY currentDistance CP getCurrPosition server debug cur_dis currentDistance abs_dis PR thisdistance else if action Event IS_ARRIVED M if PR isArrived currentDistance action Event
55. ME and give it the value C ProgramFiles lejos_nxj In short Lejos needs to know where it has been installed Notice that we now already a X Cd os SB a pono 7 Daniel Egido S nchez de Vega Section II User Manual ROBOT PATROL SYSTEM 97 use the new directory ProgramFiles that does not contain a space character When you are done click OK Verify that the new system variable shows up in the list Next we need to add the LEJOS HOME variable to the system variable Path Select Path from the list and click on Edit Add Y9LEJOS HOME bin to the end of the value The different values are separated by a colon and no colon is necessary at the end of the line Now we will test if Lejos has been installed correctly by using the DOS command prompt Click on the Window s Start button and then on All Programs gt Accessories gt Command Prompt Type in lejosdl If the result look like the one in the picture below then everything is fine We will now replace the original firmware that came with your NXT with Lejos You only need to do this once Lejos will then function as the operatin system of your NXT It implements a Java Virtual Machine on which you can run your Java programs Make sure that you NXT is connected to your computer with an USB cable and that it has been recognized by yr A SX iy Daniel Egido S nchez de Vega AN So saa E y
56. MyPosX RelPosX MyDir MyPos Y RelPos Y MyDir And to the right is Map MyPosX RelPosX RightOf MyDir MyPos Y RelPos Y RightOf MyDir And to the left is Map MyPosX RelPosX LeftOf MyDir MyPosY RelPosY LeftOf MyDir It does not want to refer to positions outside the array bounds It defines the maze array to be two maze units bigger in each dimension Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM than the real maze Then at the start of the program it sets the outer frame of the array to a value of 1 and the rest to 0 As it considers a value of 1 to be an exhausted position it will never try to reach it as the robot moves around the maze This will also prevent it from trying to move out of the entrance if the robot encounters it again for example if a loop exists Figure 52 Maze solver in a crossroads The first lines of the code check the distance to the wall at each of the four winds If the distance is smaller than some predefined value then it decides that there is a nearby wall in this direction It assumes that all accessible directions lead to an unexplored position and later it checks the map at each one of these directions If we indeed find that cell Daniel Egido S nchez de Vega 79 Section I Report ROBOT PATROL SYSTEM unexplored it continue deciding to go there next Otherwise it must decrease the number of waiting paths from the robot pres
57. OL ISIDLE dos writeBoolean idleFlag dos flush j j catch Exception e LCD clear LCD drawString 1 e getMessage 0 0 TH AR A AR AA A C4 EEeEY package selab rpss pe Patrol Commander E public interface RobotPatrolSystemServerListener pe param x param y T void startPatrol int x int y void stopPatrol Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM INTERFACE RPX GUI UserlnterfaceSubsystem Protocol RPS Agent RPS Listener TTE EH EE HC En EHE HE EHE EE HE EHE EE ERE E T package gui import guiutil rpsa RobotPatrolSystemAgent import guiutil rpsa RobotPatrolSystemListener import java awt BorderLayout import java awt Component import java awt FlowLayout import java awt event ActionEvent import java awt event ActionListener import java awt event WindowEvent import java awt event WindowListener import javax swing Box import javax swing BoxLayout import javax swing JButton import javax swing JFrame import javax swing JLabel import javax swing JPanel import javax swing JRootPane import javax swing JTextField public class UserlnterfaceSubSystem extends JFrame implements WindowListener ActionListener RobotPatrolSystemListener private static final long serialVersionUID 1L private RobotPatrolSystemAgent agent private JButton btnStart private JButton btnStop private JButton btnConnect private JBu
58. OL SYSTEM 169 public static final int STARTING 903 public static final int MOVING 904 public static final int READING SENSOR 905 public static final int CHECKING INTRUSION 906 public static final int LOCALIZING 907 public static final int CHECKING DESTINATION 908 public static final int STOPPING 909 public static final int ALARMING 912 public static final int UPDATING RANGE 913 Daniel Egido S nchez de Vega EN Section II Source Code ROBOT PATROL SYSTEM 170 package Localizer import lejos navigation Pilot import lejos nxt Motor import rpss data EncoderData public class Encoder private Pilot pilot 2 new Pilot 5 6f 11 3f Motor C Motor A false public EncoderData ED public Encoder EncoderData ED ED ED j public void readEncoder ED rightcount pilot getRightCount ED leftcount pilot getLeftCount ED distance pilot getTravelDistance PAR AR Mn De ss De D M D De D M VV package Localizer import rpss data EncoderData import rpss utilities CurrPosition import selab rpss RobotPatrolSystemServer import lejos util Timer import lejos util TimerListener public class Localizer implements TimerListener public Timer timer new Timer 50 this private Encoder EN private EncoderData ED private CurrPosition CP public Localizer CurrPosition CP_ RobotPatrolSystemServer USR EncoderData ED_ CP CP ED ED EN new Encoder ED p
59. Overrides sendData in class 12CSensor Parameters register I2C register e g 0x42 buf Buffer containing data to send len Length of data to send Returns status zero success non zero failure 9 4 getDistance public int getDistance Return distance to an object To ensure that the data returned is valid this method may have to wait a short while for the distance data to become available Returns distance or 255 if no object in range 9 5 getDistances public int getDistances int dist Return an array of 8 echo distances These are generated when using ping mode A value of 255 indicates that no echo was obtained The array must contain at least 8 elements if not 1 is returned If the distnace data is not yet available the method will wait until it is Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 223 Returns 0 if ok 0 otherwise 9 6 ping public int ping Send a single ping The sensor operates in two modes continuous and ping When in continuous mode the sensor sends out pings as often as it can and the most recently obtained result is available via a call to getDistance When in ping mode a ping is only transmitted when a call is made to this method This sends a single ping and up to 8 echoes are captured These may be read by making a call to getDistance and passing a suitable array A delay of approximately 20ms is required between the call to ping and ob
60. PATROL SYSTEM 229 void setLow int low set the normalized value corresponding to readValue 0 Methods inherited from class java lang Object clone equals finalize getClass hashCode notify notifyAll toString wait wait wait Constructor Detail 10 1 LightSensor public LightSensor ADSensorPort port Create a light sensor object attached to the specified port The sensor will be set to floodlit mode i e the LED will be turned on Parameters port port e g Port S1 10 2 LightSensor public LightSensor ADSensorPort port boolean floodlight Create a light sensor object attached to the specified port and sets floodlighting on or off Parameters port port e g Port S1 floodlight true to set floodit mode false for ambient light Method Detail 10 3 setFloodlight public void setFloodlight boolean floodlight Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 230 Set floodlighting on or off Parameters floodlight true to set floodit mode false for ambient light 10 4 readValue public int readValue Read the current sensor value Use calibrateLow to set the zero level and calibrateHigh to set the 100 level Returns Value as a percentage of difference between the low and high calibration values 10 5 readNormalizedValue public int readNormalizedValue Read the current sensor normalized value Allows more accuracy tha
61. Section I Report eerte ena 2 Chapter T Introuuelt Onus en Ear ii E E 3 1 Study of the existing technologies and projects 4 A A PETS PRU NAI FON DURER teen relie 5 31 MDI COLL Mor P US 6 4i Methodology A a 6 5b Preview Considerations sant Ea CO bh Ie ipe HU coit tiM EAS Dei ota den 7 Chapter2 THAT AW ATE sao kia Firih vH ns 8 Chapter 3 Softwares da C Dori nora ODD QUAE 26 P dure oid iior i em v DRM c PN 27 1 Bvasive Robot immense ane 29 4 EOS Y AVOIdOHCE S s nateurs ga dete 48 3 From A to B Straight sss oo 51 4 AB The least X The least Y 56 5 Line Follower aiii 60 6 Hunter errado 68 Te Tremaux Maze SONES ot 7 8 Interface for Robot Patrol System 83 Ch pler4 Conclusi ns iai tors rinse Ra radius desire lk 88 Capitulo 5 Future developments sise 90 BID OSM PII ss pro Y 92 Section II User Manual ua ao rra 93 Section IH Source COG spo A A A eu 104 Section IV Datasheets sesescsssvsssssescsccssosssssusssesecsescssssasssesesesesscssesas 202 Section I Report ROBOT PATROL SYSTEM SECTION I REPORT Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM CHAPTER 1 INTRODUCTION In this chapter it exposes a brief explanation about the project carried out which deals with developing a system of navigation for a robot As one of the characteristics and conditions in the execution of this project is
62. Sensor import lejos nxt import lejos nxt LCD import lejos nxt Motor public class EvasiveBot static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C wheel diameter trackwidth leftmotor rightmotor static UltrasonicSensor us1 new UltrasonicSensor SensorPort S7 static UltrasonicSensor us2 new UltrasonicSensor SensorPort S2 static UltrasonicSensor us3 new UltrasonicSensor SensorPort S3 static Obstacle obs new Obstacle static Avoid overcome new Avoid static String dist distance static String unit unit int total 0 total straight distance traveled void Evasion int i 0 attempts counter int n 0 avoided obstacles counter boolean r clearway true robot can avoid obstacle by the right side boolean clearway true robot can avoid obstacle by the left side int waylength 0 length of the way to travel Daniel Egido S nchez de Vega Qu y Section HI Source Code ROBOT PATROL SYSTEM 128 int distance 0 distance to left obstacle intr distance 0 distance to right obstacle boolean rl true right shortcut false left shortcut do pilot resetTachoCount tachometer reset pilot setSpeed 500 fix speed pilot forward if us1 getDistance 255 obs Closing total total int pilot getTravelDistance do distance us2 getDistance r_distance us3 getDistance if l_distance 255 clearway f
63. TEM 5 Preview Considerations Some matters must be mentioned at first There are some critical restrictions coming from the hardware that is from the Lego robot Despite being a good educational and entertainment tool we cannot forget that after all it is a toy That means that the answers of the robot many times are not optimal at all showing unfortunately sometimes a poor behavior specially the sensors which has a considerable lack of precision Other restrictions are that only can be connected four sensors to the control and the available tool is a Lego Basic Brick so the structural options are limited in reality This problem will be present during the project and it will be mentioned when necessary to underline That is why in this sense the different algorithms can now be divided in other two wholes Those are too sophisticated for the Lego robot and consequently to put in practice and those are capable or simplified to be embedded in the robot Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM CHAPTER 2 HARDWARE In this chapter it is going to explain and analyze the possibilities that the Lego tool offers It must understand the physic support where the software will be applied and the limitations in order to find out easily the potential and practical troubles and to solve them or even to look for better structural features to simplify the necessary application Most robots are desi
64. TF to true Coordinator maybe references this flag E public class PatrolTimer implements TimerListener public Timer timer 2 new Timer 100 this public TrueFalse timerFlag public PatrolTimer TrueFalse flag timerFlag flag j public void timedOut timerFlag flag true j THES GE TTEeHTEE EE EY package rpss utilities import Constants Event import Constants State public class RobotPatrolControl public int state State IDLE public RobotPatrolControl public int processEvent int event if event Event AFTER_ELAPEDTIME amp amp state State MOVING return Event AVOID TIMER else if state State IDLE if event Event START_PATROL state State CALCULATING DIRECTION return Event SETTING Daniel Egido S nchez de Vega Section II Source Code ROBOT PATROL SYSTEM 176 else if state State CALCULATING DIRECTION if event Event DIRECTION state State TURNING DIRECTION return Event TURN DIRECTION j else if state State TURNING DIRECTION if event Event TURNED state State STARTING return Event START else if state State STARTING if event Event STARTED state State MOVING return Event STARTING else if state State MOVING M if event Event AFTER ELAPEDTIME state State READING SENSOR return Event READ SENSORDATA else if event Event STOP PATROLJ state Sta
65. TROL SYSTEM 233 class Motor Regulator inner class to regulate speed also stop motor at desired rotation angle Field Summary TachoMotorPort port boolean rampUp set by smoothAcceleration forward backward setSpeed static Motor A Motor A static Motor B Motor B static Motor C Motor C Motor Regulator regulator Constructor Summary Motor TachoMotorPort port Use this constructor to assign a variable of type motor connected to a particular port Method Summary Daniel Egido Sanchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 234 void backward Causes motor to rotate backwards void flt Causes motor to float void forward Causes motor to rotate forward int getActualSpeed returns actualSpeed degrees per second calculated every 100 ms negative value means motor is rotating backward float getBasePower for debugging float getError for debugging int getLimitAngle Return the angle that a Motor is rotating to int getMode Returns the mode int getPower Returns the current power setting int getSpeed Returns the current motor speed in degrees per second int getStopAngle int getTachoCount Returns the tachometer count boolean isMoving Returns true iff the motor is in motion Daniel Egido Sanchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 235 boolean boolean void vo
66. a EN 4 Section HI Source Code ROBOT PATROL SYSTEM 168 public static final int UPDATE RANGE 29 public static final int UPDATED RANGE 36 public static final int STOPPED YESINTRUSION 30 public static final int ALARM 31 public static final int ALARMED 32 public static final int PATROL STOPPED 33 public static final int STOPPED NOINTRUSION NODEPARTED public static final int STOP PATROL 35 public static final int AVOID TIMER 100 public static final int NO defined 444 TE EeE 44Jd d TEEEEFEE T ET package Constants jen RobotPatroSubSystem I public class Protocol public static final int PROTOCOL DUMMY 999 public static final int PROTOCOL CLOSECONNECTION 000 public static final int PROTOCOL STARTPATROL 100 public static final int PROTOCOL STOPPATROL 200 public static final int PROTOCOL PATROLSTOPPED 300 public static final int PROTOCOL DEBUG 400 public static final int PROTOCOL RESULTOK 800 public static final int PROTOCOL RESULTERROR 900 public static final int PROTOCOL ISIDLE 777 THE E HE EA HEEEA T4d EA EE EBEEE package Constants e lt lt state dependent control gt gt RobotPatrolControl di public class State public static final int DLE 900 public static final int CALCULATING_DIRECTION 901 public static final int TURNING_DIRECTION 902 yi Ds Daniel Egido S nchez de Vega a Section HI Source Code ROBOT PATR
67. a d 2 e EasyAvoldance 1 import guiutil rpsa RobotPatrolSystemAgent axe aE LineFollower 1 aE LineFollower 2 6 sul la tee pruebaavo2 y impo 2 pruebaAVO3 fs User 9 9 pruebaevi Daniel Egido F 3 pruebalabe 1 e 122 RPS NXT a i RPX GUI public class UserInterfaceSubSystem extends JFrame implements Windo n E 5 8 src aver a 2 S gui laJ Cuy a t D UserlnterfaceSubSystem java NXT Coninfo Name ANIMAS E 2d 8 guiutil Fab 4 S guiutil psa x o v o a m JRE System Library jre1 6 0 02 li soi ka w bluecove jar 3 001653028032 c i a 5 classes jar Address 00165302809a e l jtools jar au pccomm jar O pctools jar 24 E lib a aE TREMAUX SOLVER Connection Disconnection atrol ST gt gt private boolean idleFlag true mos lw a gt gt ne Problems Javadoc Declaration EJ Console 52 Eu a eg nno UserinterfaceSubSystem Java Application CWProgram Files WJavakjre1 6 0 O2WbintWjavaw exe 2009 05 27 25 9 35 40 PAS UN T um 3 Java Userinterfa Y 1 22 Figure 57 Interface within Eclipse workspace Daniel Egido S nchez de Vega QOBLOYL 2235 Section I Report ROBOT PATROL SYSTEM 87 a Java UserlnterfaceSubSystem java Eclipse SDK File Edit Source Refactor Navigate Search Project Run Window Help Bales 0 E2S 0 Q 88 06 90N
68. alse Jelse clearway true if r_distance 255 r_clearway false Jelse r clearway true overcome TurnRight overcome TurnLeft overcome Return if I clearway true amp amp r_clearway true overcome Analyze if overcome get_r_last_bound overcome get last bound rl true waylength overcome get_r_travel_long Jelse rl false waylength overcome get travel long j overcome GoAround waylength rl N if I clearway true amp amp r clearway jr o k false Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 129 if overcome get r truehole true overcome Analyze if overcome get_r_last_bound lt overcome get_ _last_bound rl true waylength overcome get_r_travel_long Jelse rl false waylength overcome get travel long j overcome GoAround waylength rl n Jelse rl false waylength overcome get travel long overcome GoAround waylength rl n i 0 if I clearway false amp amp r_clearway true if overcome get truehole true overcome Analyze if overcome get_r_last_bound lt overcome get_ _last_bound rl true waylength overcome get_r_travel_long Jelse rl false waylength overcome get travel long j overcome GoAround waylength rl n Jelse Daniel Egido S
69. ated distances in order to correct the way inside and get the desired point Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM In case of a little bit more difficult final obstacle whereas there is a hole to pass the robot could get the B point Figure 34 Travel distances to get B point Daniel Egido S nchez de Vega 54 Section I Report ROBOT PATROL SYSTEM As represented in the figure in this case and the next ones the robot has got three ultrasonic sensors to make easier the accomplishment of the goal In addition for a correct and more careful performance especially when dealing with the final obstacle it has included a couple of extra functions which have to keep the robot at the same specified distance to the wall when is surrounded along its perimeter This implementation on one hand is avoiding that the robot might lose the following wall and on the other hand it slows down the speed and efficacy of the robot behavior due to have to pay attention in keeping the margin respect to the obstacle The previous registered distances modeling the obstacle later are used to travel the room and to stop just in the B point location In the experiments some problems were occasioned maybe because of the robot length and the deficient turns but at its whole the resolution is good enough Daniel Egido S nchez de Vega 55 Section I Report ROBOT PATROL SYSTEM FROM A TO B
70. ator new Actuator static Sensing sensing new Sensing static Obstacle obs new Obstacle static Avoid overcome new Avoid static String dist distance static String unit unit public static void main String args int i 0 attempts counter int n 0 avoided obstacles counter int total 0 total straight distance traveled boolean clearway do actuator counter tachometer reset actuator speed 500 fix speed actuator go if sensing distance us 255 obs Closing total total actuator distance do clearway overcome TurnRight if clearway true actuator rotate 90 overcome RAround n Jelse clearway overcome TurnLeft if clearway true T k A Daniel Egido Sanchez de Vega KO Section HI Source Code ROBOT PATROL SYSTEM 126 actuator rotate 90 overcome LAround n Jelse overcome Return overcome Retry i while i 0 amp amp i lt 3 if i gt 2 actuator stop total total overcome get l2 while n lt 4 total lt 300 Sound beepSequence LCD clear LCD drawString dist 0 0O LCD drawint total 6 0 Daniel Egido Sanchez de Vega Section III Source Code ROBOT PATROL SYSTEM 127 FROM A TO B STRAIGHT Obstacle Idem Avoid Idem EvasiveBot AB STRAIGHT TEE EH EHE EHE HE EHE He EHE EHE EE HE EHE TEL import lejos navigation Pilot import lejos nxt Ultrasonic
71. c project is not under restrictions of a robot competition though if desired it can follow some rules or standard specifications if being helpful or in order to have a previous guidance so there is a wider freedom to decide and act For this kind of challenge the robot needs some strategy to find the way out of the labyrinth The most usual approach is the robot follows all time the right wall or the left wall This is too typical so it has been omitted Instead it has preferred to use a different algorithm more useful as following the wall works in many general mazes but there are some labyrinth that are prepared for that this method fails for example when the exit is not located in the external wall but in one of the internal ones For these cases there are other not so common algorithms such as the so called Tremaux s algorithm which is used here This method requires memory because the robot has to memorize the information about the maze for instance the way already travelled or the way not visited yet For that the maze is divided in cells Daniel Egido S nchez de Vega 72 Section I Report ROBOT PATROL SYSTEM 73 To put in practice this application it has built a labyrinth after design and as in the previous other environments it has used the white hard paper The chosen design is a 10x10 Matrix which is divided in 25x25 cm cells such measurements are the robot length n MN Nu SR M N MN m
72. cSensor us2 new UltrasonicSensor SensorPort S2 static UltrasonicSensor us3 new UltrasonicSensor SensorPort S3 Firstly it is assumed the initial robot position as zero and north oriented static int x7 0 initial x position static int y7 0 initial y position void LeastY int x2 int y2 if y2 y1 actuator rotate 180 Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 147 void keepLdistance actuator go actuator speed 200 while sensing distance us2 gt 10 amp amp sensing distance us2 actuator speed 200 lt 25 Motor B setSpeed 210 void keepRdistance actuator go actuator speed 200 while sensing distance us3 gt 10 amp amp sensing distance us3 actuator speed 200 lt 25 Motor A setSpeed 210 j void WayCorrection int di 0 int d2 0 int d3 0 if overcome get_part 1 actuator counter while sensing distance us3 lt 25 voyager keepRdistance d1 actuator distance actuator rotate 90 actuator counter while sensing distance us3 lt 25 voyager keepRdistance d2 actuator distance if d2 gt overcome get l1 actuator rotate 90 actuator counter while sensing distance us3 lt 25 Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 148 voyager keepRdistance d3
73. ce angle deg while deg 90 if angle lt 70 clearway false Jelse clearway true j return clearway j try to avoid obstacle by the left boolean TurnLeft boolean clearway if clearway false deg 0 do deg deg 10 pilot rotate 10 if us getDistance 255 bound us getDistance angle deg while deg 90 if angle gt 70 HT DA repo A Daniel Egido Sanchez de Vega EN 4 a Section HI Source Code ROBOT PATROL SYSTEM clearway false Jelse clearway true return clearway Jelse return clearway backwards void Retry while us getDistance obs get dis 5 pilot backward pilot stop j Turn back Repositioning void Return pilot rotate deg Analyze the obstacle int Analyze int travel_long 0 travel travel_long int bound Math sin Math toRadians angle travel long travel long 25 plus robot length return travel long Go around the obstacle void GoAround int travel long ints angle 0 int s bound 0 angle 0 if clearway true pilot travel travel_long if deg gt 0 pilot rotate 90 pilot stop while us getDistance 255 angle angle 10 Daniel Egido Sanchez de Vega 107 Section HI Source Code ROBOT PATROL SYSTEM 108 pilot rotate 10 j j if deg 0 pilot rotate 90 pilot stop while
74. choCount while us2 getDistance lt 25 voyager keepLdistance d1 int pilot getTravelDistance pilot rotate 90 pilot resetTachoCount while us2 getDistance lt 25 voyager keepLdistance d2 int pilot getTravelDistance if d2 gt overcome get_r_travel_long pilot rotate 90 pilot resetTachoCount while us2 getDistance lt 25 voyager keepLdistance d3 int pilot getTravelDistance if d3 gt 2 d1 pilot stop LCD clear LCD drawString no way 0 0 Jelse pilot rotate 90 pilot travel d2 overcome get r travel long pilot rotate 90 pilot travel d1 d3 pilot stop Sound beepSequence LCD clear LCD drawString Destination 0 0 Jelse pilot rotate 90 pilot travel d1 pilot rotate 90 Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 135 pilot travel overcome get r travel long d2 pilot stop Sound beepSequence LCD clear LCD drawString Destination 0 0 if overcome get_part 4 pilot stop Sound beepSequence LCD clear LCD drawString Destination 0 0 public static void main String args Firstly it has to provide the destination int x2 150 int y2 150 voyager Orientation x2 y2 do wayfinder Evasion while wayfinder get_total lt Math sqrt Math pow x2 2 Math pow y2 2 amp amp overcome get_part
75. d travel float distance boolean immediateReturn Moves the NXT robot a specific distance Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM void void void turn float radius Moves the NXT robot in a circular path with a specified radius The center of the turning circle is on the right side of the robot if parameter radius is negative Postcondition Motor speeds are unpredictable turn float radius int angle Moves the NXT robot in a circular path with a specified radius The center of the turning circle is on the right side of the robot if parameter radius is negative Robot will stop when total rotation equals angle turn float radius int angle boolean immediateReturn Moves the NXT robot in a circular path with a specified radius The center of the turning circle is on the right side of the robot if parameter radius is negative Robot will stop when total rotation equals angle Method Detail 7 1 forward void forward Moves the NXT robot forward until stop is called See Also Navigator stop 7 2 backward void backward W und a Daniel Egido S nchez de Vega 207 Section IV Datasheets ROBOT PATROL SYSTEM 208 Moves the NXT robot backward until stop is called See Also Navigator stop 7 3 stop void stop Halts the NXT robot and calculates new x y coordinates See Also Navigator forward 7 4 isMoving boolean i
76. deg deg deg 10 pilot rotate 10 r bound us1 getDistance overcome Truebound try to avoid obstacle by the left void TurnLeft ie 7 Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 113 deg 0 while us1 getDistance 255 deg 90 truehole false angle deg deg deg 10 pilot rotate 10 bound us1 getDistance overcome Truebound obstacle s hole detection void Truebound intr hole 0 int hole 0 r hole r_bound 25 int Math cos Math toRadians 90 deg r bound hole _bound 25 int Math cos Math toRadians 90 deg _ bound if r_hole lt r_bound r_last_bound Jelse r truehole true r truehole false if hole lt bound last bound truehole true Jelse r last bound r bound last bound bound truehole false void SecondaryTruebound int sec r hole 0 int sec hole 0 int sec r bound 0 int sec bound 0 sec r bound us3 getDistance sec bound us2 getDistance sec r hole sec r bound 25 int Math cos Math toRadians deg sec r bound sec hole sec bound 25 int Math cos Math toRadians deg sec bound if sec r hole sec r bound r last bound Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 114 r_truehole true Jelse r truehole fa
77. director in our ProgramFilesNlejos nxj directory Select v classes jar and press Open The Lejos library will now be listed ML We stay in the properties and move to the Java Compiler section listed in the left panel Check the box Enable project specific settings and choose level 1 3 for the compiler compliance level This will urge the compiler to optimize for an earlier version of Java This earlier version is more suitable for the NXT since it was developed for embedded systems It requires much less resources than the latest version of Java Click on Apply and then OK to leave the properties The next step is to configure Eclipse for downloading the software into the NXT Click on Run gt External Tools gt Open External Tools Dialog Daniel Egido S nchez de Vega 100 Section II User Manual ROBOT PATROL SYSTEM Select Program on the left and then click on the New icon Name the tool leJOS Download on top In the Main tab enter the location of the lejosdl bat file that should be in the lejos nxj bin directory ny clickin on Browse File System Enter project loc bin in the Working directory and enter ijava type name in the Arguments section Now we will create a shortcut for downloading your program into the NXT Click on the little green run icon with toolbox and then select Organiz
78. e Favorites Click on Add in the popup window and then check the box in front of leJOS Download which is the external tools we configured in the previous step Press OK and then Ok again 5 4 5 Write download and run a Hello world program First we need to create the main class of your program Click on New gt Class Name it HelloWorld and check the box public static void Strin args You will receive an almost empty class Eclipse is a very Daniel Egido S nchez de Vega 101 Section II User Manual ROBOT PATROL SYSTEM smart Java editor that tries to compile your program while you write Similar to M Word it will underline errors with a red line Sometimes this automatic compilation does not work and you want to force Eclipse to compile You can achieve this by simply saving the file You now need to to enter a few lines of Java code In the first line add import lejos nxt LCD This line will enable your program to use the LCD display of your NXT Next we need to define what should be displayed and when Add the following lines to the main method LCD drawString Hello World 2 2 LCD refresh while true lt Now you can safe the program and then download it into the NXT The next screenshot walks you through these steps Before you start the downloading procedure you must make sure that the NXT is connected to the computer and that the NXT is recognized by
79. e example explained above many other applications are possible for a robot with these characteristics Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 3 Objectives In general terms it can say clearly that the main objective is to provide a robot with a navigation system composed of some different algorithms for enabling the robot to manage the diverse environments which of course are determined in advance In a little more detail the whole of algorithms can be classified in two groups Those are focus on any standard competition such as Maze Solver LineFollower or Hunter Prey and those are not focus on any standard such as Obstacle Avoidance In the case of the last one anyway there will have to be some restrictions in the environment for a suitable accomplishment of the goals 4 Methodology The way to get the eventual objective is a logic process which consists of studying the object oriented programming language called JAVA at first time Later it has to study the workspace which it is going to work with called Eclipse a useful tool supporting JAVA After that it carries out the main stage that is the development of the algorithms by considering the alternatives requirements and capabilities Finally the robot is built with a Lego Brick some environments are made if necessary and the algorithms are put in practice Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYS
80. e robot trajectory are not correct oriented In the next figure it show the analogue travelled path with AB LeastY algorithm which treats about approaching the Y coordinate before getting the X coordinate and consequently the destination 4 Figure 37 Example of AB LeastY Daniel Egido S nchez de Vega 58 Section I Report ROBOT PATROL SYSTEM These are just different manners to manage this kind of objectives and environments Arbitrarily the robot will always try the right path and later the left one but it can be changed in the source code as sometimes can be more or less convenient to give priority in one or other shift It does not forget that here also the tricky final obstacle can take place so the corresponding functions are implemented Figure 38 Lego Robot with three ultrasonic sensors connected Daniel Egido S nchez de Vega 59 Section I Report ROBOT PATROL SYSTEM HUNTER This algorithm well could not belong to this project but it considered also interesting and a typical application in general mobile robotics so it decided to try programming somehow anyway despite knowing is not possible to put in practice as it is necessary other robot the prey which is not available It is a simple game or competition but complicated program especially in this case as the robot does not know the environment in advance Usually this event is planned by making a simulation and the rob
81. econd Methods that use the tachometer regulateSpeed rotate rotateTo These rotate methods may not stop smoothly at the target angle if called when the motor is already moving Motor has 2 modes speedRegulation and smoothAcceleration which only works if speed regulation is used These are initially enabled The speed is regulated by comparing the tacho count with speed times elapsed time and adjusting motor power to keep these closely matched Smooth acceleration corrects the speed regulation to account for the acceleration time They can be switched off on by the methods regulateSpeed and smoothAcceleration The actual maximum speed of the motor depends on battery voltage and load With no load the maximum is about 100 times the voltage Speed regulation fails if the target speed exceeds the capability of the motor If you need the motor to hold its position and you find that still moves after stop is called you can use the lock method Example Motor A setSpeed 720 2 RPM Motor C setSpeed 720 Motor A forward Motor C forward Thread sleep 1000 Motor A stop Motor C stop Motor A regulateSpeed true Motor A rotateTo 360 Motor A rotate 720 true h while Motor A isRotating int angle Motor A getTachoCount should be 360 Author Roger Glassey revised 9 Feb 2008 added lock method Nested Class Summary Daniel Egido Sanchez de Vega Section IV Datasheets ROBOT PA
82. ent position as well as from the position we look at Really the only way it is going to encounter a visited position while traveling in an unexplored route is if it is closing a loop so the previously traveled position must have had more than one path available when the robot was there And of course it has to take into account that anyway it must decide a priority in choosing ways according to that It has to mention this source code is a right hand rule code If all paths are accessible and unexplored the program preference is to first turn right if not the next option is to move forward and the last option is to turn left Figure 53 Maze solver traveling the labyrinth Daniel Egido S nchez de Vega N gt R 80 Section I Report ROBOT PATROL SYSTEM When it has decided finally about the next step the robot rotates to that direction and move forward Once it has reached a new emerging route position it returns to the start of the while loop and it looks and checks again for a the next step a path to take In the maze sample designing and tried looking the robot performance it could say that it is moving by following right wall but it is not true due to previously mentioned this algorithm is applying the right hand rule but anyway it could be changed and it would being the Tremaux s method A better and clearer behavior would be seen in a maze with inner way out as already mentioned where f
83. ential drive robot respect to the direction of its wheels T Daniel Egido S nchez de V LOUE anie O anchez ae veea LON de 5 5 sen Section I Report ROBOT PATROL SYSTEM 11 Left Wheel Stationary Stationary Stationary Forward Forward Forward Backward Backward Backward Right Wheel Stationary Forward Backward Stationary Forward Backward Stationary Forward Backward Robot Rests stationary Turns counterclockwise pivoting around the left wheel Turns clockwise pivoting around the left wheel Turns clockwise pivoting around the right wheel Goes forward Spins clockwise in place Turns counterclockwise pivoting around the right wheel Spins counterclockwise in place Goes backward Table 1 Differential Drive behavior respect to the wheel direction Ref DAMG07 At different combinations of speed and direction the robot makes turns of any possible radius This maneuverability the capability to turn in place in particular makes the differential drive the ideal candidate for many kind of projects and applications And taking into account that it is very easy to implement that is why a significant percentage of all mobile LEGO robots belong to this category It is really useful for tracking the robot position and it requires very simple math Only one main drawback is found out It is not easy to get the robot to move in a perfectly straight line Because the mo
84. eport ROBOT PATROL SYSTEM 92 BIBLIOGRAPHY 1 Aqu las referencias bibliogr ficas Con este estilo CHRI98 JAVA Teach Yourself 2001 Author Chris Wright Editorial McGraw Hill JOPE08 Java Foundations 2008 Introduction to program design and data structures Authors John Lewis Peter DePasquale Joseph Chase Addison Wesley Pearson International Edition DAMG07 Lego Mindstorms NXT 2007 Authors Dave Astolfo Mario Ferrari Giulio Ferrari Editorial Syngress LEJOS http lejos sourceforge net index php BARTOS http www bartneck de 2008 03 04 java lego nxt eclipse tutorial ffinstallJava Daniel Egido S nchez de Vega Section II User Manual ROBOT PATROL SYSTEM SECTION II UsER MANUAL Daniel Egido S nchez de Vega 93 Section II User Manual ROBOT PATROL SYSTEM 94 In this section it is include a kind of tutorial about how to install JAVA and ECLIPSE tool in the computer in order to set appropiately the environment in which it must work Ref BARTOS You do NOT need to install the JDK Java Developer Kit We will install Eclipse later which does already include all the tools you need to write and compile your programs After the installation you also do NOT need to set any Path or Classpath variables for Java itself Java will be installed in C Program Files Java However if you cannot even get Java to work on your machine enter the path to your java bin directory
85. es left a negative value right clockwise immediateReturn If immediateReturn is true then the method returns immediately and your code MUST call updatePostion when the robot has stopped Otherwise the robot position is lost 7 16 getAngle float getAngle Returns the angle of rotation of the robot since last call to reset 7 17 getTravelDistance float getTravelDistance Returns Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 212 distance traveled by the robot since last call to reset 7 18 steer void steer int turnRate Moves the NXT robot in a circular path at a specific turn rate The center of the turning circle is on the right side of the robot if parameter turnRate is negative Values for turnRate are between 200 and 200 The turnRate determines the ratio of inner wheel speed to outer wheel speed as a percent Formula ratio 100 abs turnRate When the ratio is negative the outer and inner wheels rotate in opposite directions Examples e steer 25 gt inner wheel turns at 75 of the speed of the outer wheel e steer 100 gt inner wheel stops e steer 200 gt means that the inner wheel turns at the same speed as the outer wheel a zero radius turn Note Even if you have specified a drift correction in the constructor it will not be applied in this method Parameters turnRate If positive the left wheel is on the inside of the turn If
86. esetTachoCount tachometer reset pilot setSpeed 500 fix speed pilot forward if us getDistance 255 obs Closing total total int pi ot getTravelDistance do clearway overcome TurnRight clearway overcome TurnLeft clearway if clearway false amp amp overcome get angle gt 0 overcome Return overcome Retry i if clearway true waylength overcome Analyze overcome GoAround waylength n while i 0 amp amp i lt 3 if i gt 2 pilot stop e Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 110 total total overcome get s long j while n 4 total lt 300 Sound beepSequence LCD clear LCD drawString dist 0 0O LCD drawint total 6 0 Daniel Egido Sanchez de Vega Section II Source Code ROBOT PATROL SYSTEM 111 EVASIVE ROBOT 2 Obstacle Avoid EvasiveBot HEHEHEHEH EHEHEHE EE HE EHE EE EE A A HER import lejos navigation Pilot import lejos nxt import lejos nxt UltrasonicSensor public class Obstacle static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C static UltrasonicSensor us1 new UltrasonicSensor SensorPort S7 int c 0 obstacles counter int dis 20 distance to obstacle int t 0 void Closing move close to sensed obstacle C Sound beepSequenceUp do dis us1 getDistance in cm while dis 5 pilot stop when robot is
87. final int PROTOCOL ISIDLE 777 TEM EET A HHH D En Dee VA package guiutil rpsa import guiutil Protocol import java io DatalnputStream import java io DataOutputStream import java io EOFException import java io IOException import java util concurrent ArrayBlockingQueue import lejos pc comm NXTComm import lejos pc comm NXTCommException import lejos pc comm NXTCommFactory import lejos pc comm NXTInfo fer RobotPatrolSystem El public class RobotPatrolSystemAgent implements Runnable y Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 197 private NXTComm nxtComm NXTCommFactory createNXTComm NXTCommFactory BLUETOOTH private DatalnputStream dis private DataOutputStream dos private ArrayBlockingQueue queue new ArrayBlockingQueue 100 private RobotPatrolSystemListener listener null private boolean isRunning false public boolean connect String name String address boolean result false if name null name length 0 address null address length 0 System out printin Name DANIMASTER Address 00165302809a NXTInfo nxtinfo new NXTInfo 1 System exit 1 nxtinfo 0 new NXTInfo name address System out println Connecting to nxtInfo 0 btResourceString try result nxtComm open nxtlnfo 0 catch NXTCommException e j System out println Connected to nxtInfo 0 btResourceString res
88. g the motors independently so the robot can follow the black line without complications if it is well defined and there is no tricky places Daniel Egido Sanchez de Vega 69 Section I Report ROBOT PATROL SYSTEM 70 The second one is a little more sophisticated using exceptions and the LCD but despite of differences in the code in essence it is the same Figure 46 Robot following the black line The performance in the experiments was very successful Even the robot got to move quite faster than expected In the next figure it can observe the good performance of the light sensor the bright coming from the white area respect to the black one is easy to appreciate Daniel Egido S nchez de Vega EN Section I Report ROBOT PATROL SYSTEM 71 Figure 47 Light sensor in action However if the light sensor is not so close to the floor the action results quite more deficient so the range of actuation is really short at least in this case in which it needs a totally clear difference between both regions as it is working in the limit of the line Daniel Egido S nchez de Vega EN M Section I Report ROBOT PATROL SYSTEM MAZE TREMAUX SOLVER The maze solver robot is other good and interesting point of this project It is being also a well known application in the robotics fans world This application takes places in many competitions with standard or non regular rules and conditions This specifi
89. gle by connecting the results Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 44 So 5 PRR Figure 28 Triangles calculations cos 10 6 52 xi 6 42 x2 7 78 6 42 1 36 1 36 sen 60 5a h 2 Ec 3 Relation distance angle Daniel Egido S nchez de Vega La y Section I Report ROBOT PATROL SYSTEM The result of this short study is that with these data it confirms that there is a little enough difference in increasing the whole radial turn the obtained relation is that if the angle is multiplied by five the distance is only increased in two centimeters so it is no problem It takes this data for implementation in the robot application A last factor must be mentioned about this algorithm Implementing this program the robot is able to estimate when calculating the obstacle s corner if there is a possible way in case of existing a hole between two close obstacles by calculating the hole width and if it is large enough for the robot size this variable will be added to the decision of which way should be taken Daniel Egido S nchez de Vega X 45 Section I Report ROBOT PATROL SYSTEM 46 b e h NB TP A Figure 29 Calculating the hole The robot registers the bound distance b and just the next one NB so it can already estimate approximately the hole s width h It must be at least the sum of the bound distance plus the robot length in
90. gned with some kind of mobility in mind Motion makes this machines animated Most mobile robots belong to one of two categories wheeled robots or legged robots Though legs provide an effective way to move on rough terrains wheels are generally much more efficient on smooth surfaces Attention will be focus on surveying some common wheeled mobility configurations discussing some of their pros and cons Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM Simple Differential Drive This architecture has many advantages especially in its simplicity that is why it is the most often used configuration for LEGO mobile robots A differential drive is made of two parallel drive wheels on either side of the robot powered separately with one or more casters pivoting wheels which help support the weight but that have no active role because the robot motion vector results from two independent components Figure 1 Simple Differential Drive Ref DAMG07 of Si M Daniel Egido S nchez de Vega ates y Section I Report ROBOT PATROL SYSTEM 10 Figure 2 Real built Differential Drive In the case of the two drive wheels turn in the same direction at the same speed the robot goes straight But when the the wheels rotate at the same speed but in opposite directions the robot turns in place pivoting around the midpoint of the line that connects the drive wheels Table 1 shows the behavior of a differ
91. he inside of the turn If negative the left wheel is on the outside 7 22 turn void turn float radius int angle Moves the NXT robot in a circular path with a specified radius The center of the turning circle is on the right side of the Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 215 robot if parameter radius is negative Robot will stop when total rotation equals angle If angle is negative robot will move travel backwards Parameters radius The radius of the turning circle angle The sign of the angle determines the direction of robot motion 7 23 turn void turn float radius int angle boolean immediateReturn Moves the NXT robot in a circular path with a specified radius The center of the turning circle is on the right side of the robot if parameter radius is negative Robot will stop when total rotation equals angle If angle is negative robot will move travel backwards Parameters radius The radius of the turning circle angle The sign of the angle determines the direction of robot motion immediateReturn If immediateReturn is true then the method returns immediately and your code MUST call updatePostion when the robot has stopped Otherwise the robot position is lost 7 24 reset void reset Reset traveled distance and rotated angle Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 8 Package lejos nxt
92. he current robot trajectory If the obstacle is not right angled to the robot sensor shoot the obstacle probably will not be detected The usual perform results in ray deviation from the sensor thus the sensor receiver does not get the signal implying there is an obstacle near the current position Figure 16 Facing a non right angled obstacle All this limitations in the environment features are mainly due to that the robot use an ultrasonic sensor so its rays must be straightly Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 32 directed and returned Otherwise the detection is never successful Also it takes into consideration that in this first algorithm the robot just can be provided with an only sensor Moreover in this case the angular range of the sensor is theoretically unknown so it has only got a approximation from the real trials with the consequence of the variability in the measurements being less reliable ones Under these circumstances it would be appropriate to take a possible approximation of 30 that means 15 spread in each side from the straightforward robot vision line This supposition in many cases does not underlay great difference Figure 17 Robot sensor radial range Before facing the obstacle the robot looks around and calculates which the shortest way is to surround the obstacle For that the robot turns covering a middle circumference take a meas
93. he obstacle void RAround actuator rotate 90 do ap TD Daniel Egido S nchez de Vega x ps Section HI Source Code ROBOT PATROL SYSTEM 124 actuator rotate 90 actuator travel 40 11 40 actuator rotate 90 pilot stop while sensing distance us 255 actuator travel 40 12 40 actuator rotate 90 while sensing distance us 255 actuator rotate 90 actuator travel 30 12 30 actuator rotate 90 actuator travel 1 actuator rotate 90 void LAround do actuator rotate 90 actuator travel 40 11 40 actuator rotate 90 pilot stop while sensing distance us 255 actuator travel 40 12 40 actuator rotate 90 while sensing distance us 255 actuator rotate 90 actuator travel 30 12 30 actuator rotate 90 actuator travel 1 actuator rotate 90 int get 1 int get l2 return 1 return 1 Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 125 TTT TTT TTT EE E A E A import lejos navigation Pilot import lejos nxt LCD import lejos nxt Motor import lejos nxt SensorPort import lejos nxt Sound import lejos nxt UltrasonicSensor public class EvasiveBot static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C wheel diameter trackwidth leftmotor rightmotor static UltrasonicSensor us new UltrasonicSensor SensorPort S1 static Actuator actu
94. hen the robot or vehicle turns the inner wheel goes along a tighter bend than the outer one In large radius turns the difference is not appreciable but in small radius turns become relevant and that causes one of the wheels skids Then it can apply the Ackerman Steering to avoid the skidding and consequently the difference of angle among wheels It works on the next way When the lines extended from any wheel axle meet and revolve around one common point the vehicle turns smoothly It is shown in the next figure Figure 10 Ackerman Steering scheme Ref DAMG07 It can see a wheel allocated just below the pivoting axle which does not affect the steering If the wheel is allocated behind its steering column friction causes the dynamic forward motion of the car to push the wheels toward the rear it implies a self centering action A good Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM example is the well known of a shopping cart it can appreciate that the current wheel contact area is behind the pivoting axis The more the wheel is moved behind the pivoting axis the more self centering it gets d Figure 11 Movement of wheel from pivoting axle Ref DAMG07 The steering drive is a suitable configuration for rough terrains because it is very stable on its four wheels It is possible to improve the grip with the ground if any kind of suspension is used An important point to take into account is that no
95. hics output to the LCD display A simple output stream that implements console LCDOutputStream output LightSensor Abstraction for a NXT light sensor Motor Abstraction for a NXT motor MotorPort Abstraction for a NXT output port NXT Abstraction for the local NXT Device Poll Provides blocking access to events from the NXT SensorPort Abstraction for a NXT input port Settings leJOS NXJ persistent settings Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 218 Sound NXT sound routines SoundSensor Abstraction for a NXT sound sensor This class is designed for use by other lejos classes to SystemSettings read persistent settings TextMenu Displays a list of items TouchSensor Abstraction for a NXT touch sensor UltrasonicSensor Abstraction for a NXT Ultrasonic Sensor Error Summary FlashError 9 lejos nxt Class UltrasonicSensor java lang Object lejos nxt I2CSensor L lejos nxt UltrasonicSensor All Implemented Interfaces SensorConstants public class UltrasonicSensor extends I2CSensor Abstraction for a NXT Ultrasonic Sensor WARNING THIS CLASS IS SHARED BETWEEN THE classes AND pccomms PROJECTS DO NOT EDIT THE VERSION IN pccomms AS IT WILL BE OVERWRITTEN WHEN THE PROJECT IS BUILT Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM Field Summary Fields inherited from interface lejos nxt SensorConstants 219 MO
96. hitecture has its own features Tracks moving on rough floors have a better grip than wheels but not on soft ones Tracks implies quite friction that spend some of the power supplied by the motors Because of the unavoidable skidding in this architecture it has not chosen this option as it is very disadvantageous for applications in which it must calculate the position of the robot by its position Daniel Egido S nchez de Vega ye Section I Report ROBOT PATROL SYSTEM 19 Steering Drive A steering drive is the most typical style which is used in many vehicles and cars It is characterized by two front steering wheels and two fixed rear wheels The best way usually is to conduct the rear one However this is less versatile than differential drives and impossible to steer in place Among the advantages of this configuration it can find Easy capability to drive straightly and quite stability Figure 9 Steering Drive Ref DAMG07 Two motors drive the rear wheels one for each and one motor drives the steering mechanism It implies a different control of steering and driving motors consequently allowing more precision in steering but Daniel Egido S nchez de Vega s Y x Section I Report ROBOT PATROL SYSTEM 20 deficient capability to turn in place In some cases it could be necessary to turn the robot smoothly and in the usual conditions about wheels and floor might became difficult as in reality w
97. ial part called the turntable a large round rotating platform usually used in LEGO models It can attach two pulley wheels and drive it with an axle that passes through the center of the turntable This is necessary because the wheel must be connected to the part of the turntable that gets rotated by the external gear To build a complete synchro drive it is necessary at least three of these turntables Then it has to connect them in the way of that one motor can drive all the axles at the same time while another can turn all the wheels in synchronization Daniel Egido S nchez de Vega 23 Section I Report ROBOT PATROL SYSTEM Figure 13 An assembled wheel for Synchro Drive Other Configurations Some more sophisticated or specialized possibilities for mobile architectures Multi Degree of Freedom MDOF This option has three or more wheels or even groups of them both independently turned and driven It has to guess a synchro drive in which each wheel can change its velocity and orientation without connection to the others A robot with this characteristic would be able to behave like a differential drive a steering drive or a synchro drive only by controlling its configuration from the software They are really difficult to build and control Daniel Egido S nchez de Vega E M 24 Section I Report ROBOT PATROL SYSTEM Articulated drive It is quite similar to the steering drive but instead of steering
98. ic float getBasePower for debugging Returns base power of regulator 11 36 setBrakePower public void setBrakePower int pwr Daniel Egido S nchez de Vega 245
99. id void void void void void isRegulating isRotating returns true when motor rotation task is not yet complete a specified angle lock int power Applies power to hold motor in current position regulateSpeed boolean yes turns speed regulation on off Cumulative speed error is within about 1 degree after initial acceleration resetTachoCount Resets the tachometer count to zero reverseDirection Reverses direction of the motor rotate int angle causes motor to rotate through angle rotate int angle boolean immediateReturn causes motor to rotate through angle iff immediateReturn is true method returns immediately and the motor stops by itself If any motor method is called before the limit is reached the rotation is canceled rotateTo int limitAngle causes motor to rotate to limitAngle Then getTachoCount should be within 2 degrees of the limit angle when the method returns Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 236 void rotateTo int limitAngle boolean immediateReturn causes motor to rotate to limitAngle if immediateReturn is true method returns immediately and the motor stops by itself and getTachoCount should be within 2 degrees if the limit angle If any motor method is called before the limit is reached the rotation is canceled void setBrakePower int pwr void setPower int power sets motor powe
100. iel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 204 A Pilot that keeps track of direction using a CompassPilot CompassSensor The SimpleNavigator class can keep track of the robot position and the direction angle it faces It uses a pilot object to control NXT robot movements SimpleNavigator The position and direction angle values are updated automatically when the movement command returns after the movement is complete and and after stop command is issued TachoNavigator Deprecated in 0 8 use SimpleNavigator The TachoPilot class is a software abstraction of the TachoPilot Pilot mechanism of a NXT robot The WaypointNavigator class extends the WaypointNavigator SimpleNavigator allowing the specify a path along a set of coordinates 7 lejos navigation Interface Pilot All Known Implementing Classes CompassPilot TachoPilot public interface Pilot The Pilot interface forms a common set of functions an implementation must offer in order to be used by higher level navigation classes The Pilot hides the details of the robots physical construction and the required control algorithms from the rest of this package Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 205 Method Summary void backward Moves the NXT robot backward until stop is called void forward Moves the NXT robot forward until stop is called a float getAngle floa
101. in 3cm of the obstacle stops int get_dis return dis TTT TTT import lejos navigation Pilot import lejos nxt Motor import lejos nxt SensorPort import lejos nxt UltrasonicSensor import java lang Math Daniel Egido Sanchez de Vega EN ye Section HI Source Code ROBOT PATROL SYSTEM 112 public class Avoid static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C static UltrasonicSensor us1 new UltrasonicSensor SensorPort S1 static UltrasonicSensor us2 new UltrasonicSensor SensorPort S2 static UltrasonicSensor us3 new UltrasonicSensor SensorPort S3 static Obstacle obs new Obstacle static Avoid overcome new Avoid static int deg 0 angle follower static int d 0 distance traveled static double r angle 0 right bound angle static double angle 0 heft bound angle static int r bound 0 obstacle s right bound static int bound 0 obstacle s left bound static int next bound 0 for hole detection boolean truehole false detection of true obstacle s left hole boolean r truehole false detection of true obstacle s right hole int travel long 0 left distance to travel int r travel long 0 right distance to travel intr last bound 0 int last bound 0 try to avoid the obstacle by the right void TurnRight deg 0 while us1 getDistance 255 deg 90 r truehole false r_angle
102. into the Path variable If you already have Java installed you need to verify that you have at least version 5 preferable of the JRE but the JDK will work as well We will install Eclipse which does require at least this version 5 1 2 Install Lego USB driver on your computer The NXT can be connected to the computer via USB or Bluetooth The communication via USB is more reliable and faster than via Bluetooth The later also depends on each specific computer model USB is in comparison more standardized You must first install the driver and only then connect the NXT with the USB cable You do NOT need to install the any software that comes on the Mindstorms CD because we will NOT program in NXT G Lego s own software that is based on Labview We only need to install the USB driver which is available on the Mindstorms website If you already installed the original Mindstorms software then you do not need to uninstall it just check if the Mindstorms website has an update for the USB driver Daniel Egido S nchez de Vega EN a Section II User Manual ROBOT PATROL SYSTEM Download the Mindstorms NXT Driver E 2746 9 s 2746 9 i s A Az mnasrnres oa bey E Unzip the file and start setup exe E a un un r L2 JO E fo nme o ae a eens LIT Windows might ask you to restart the computer after the installation
103. is the time to turn to Daniel Egido S nchez de Vega 63 Section I Report ROBOT PATROL SYSTEM go on the zigzag then some deviation occurs and the next orientation is not already exactly the requested one For the robot does a zigzag movement suiting the environment it must know the size of the square so it would be the only detail about it that the robot would know in advance The program does not allow so much complexity so there are some disadvantages Unfortunately the sensing is discrete that means the robot cannot find the prey in any moment so there are checkpoints where the hunter can see the prey and the other times do not For example whereas avoiding obstacle the hunter cannot pursue the prey though saw him The most important checkpoints where the hunter takes advantage to look around are shown in the next figure Daniel Egido S nchez de Vega 64 Section I Report ROBOT PATROL SYSTEM Figure 41 Main Checkpoints in Zigzag Hunting When the hunter finishes the zigzag covering the area of the environment go straight back to the exit point and if the prey is not found it starts again As it can appreciate the checkpoints are well determined There are up to four checkpoints in the line crossing the square by the middle it provides the hunter with a wide view and a good position to act quickly and affectivity Daniel Egido S nchez de Vega 65 SectionI Report ROBOT PATROL SYST
104. lse if sec hole bound last bound truehole true Jelse truehole false r last bound r bound last bound bound backwards void Retry while us1 getDistance obs dis 5 pilot backward pilot stop Turn back Repositioning void Return pilot rotate deg Analyze the obstacle void Analyze travel long bound int Math sin Math toRadians _angle travel long travel long 25 plus robot length r travel long r bound int Math sin Math toRadians r angle r travel long r travel long 25 plus robot length int get r travel long int get travel long j yf i LA 4 return r travel long Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 115 return travel long int get last bound return last bound int get r last bound return r_last_bound boolean get_r_truehole return r_truehole boolean get truehole return truehole j int get d return d Go around the obstacle void GoAround int travel long boolean rl if rl false pilot rotate 90 pilot travel travel_long pilot rotate 90 pilot resetTachoCount tachometer reset pilot setSpeed 200 fix speed while us3 getDistance 255 pilot forward pilot travel 25 d int pilot getTravelDistance pilot rotate 90 pilo
105. m the environment is really restricted and whose orientation has to be preplanned before robot performance To get the B point the robot being independent the orientation has to estimate also the straight distance to travel Then the robot is registering the distance it is being travelled while on the way Daniel Egido S nchez de Vega 51 Section I Report ROBOT PATROL SYSTEM 52 In this application may take place a tricky situation which lead to the robot to a wrong final position That occurs when the B point is enclosed in some connected obstacles forming a structure of U Thus when the robot finishes the counting and it thinks the total distance is already travelled and it is placed on the B point actually is not The next figure can shed a idea about what it means Figure 32 B point enclosed within tricky obstacle To manage this challenge it has added a new function in the algorithm so called WayCorrection in which some breakpoints are saved in order to determine in which position the robot finish travelling Daniel Egido Sanchez de Vega Section I Report ROBOT PATROL SYSTEM 53 and get stopped Thus knowing the position and depending on which one it runs an action or other one always focus on going inside the room where the B point is placed Figure 33 Estimation of the final obstacle While the robot is surrounding the obstacle it is measuring and registering the indic
106. n III Source Code ROBOT PATROL SYSTEM 195 if event getSource equals btnStart startPatrol else if event getSource equals btnStop stopPatrol else if event getSource equals btnConnect Connect else if event getSource equals btnDisconnect Disconnect RobotPatrolSystemListener public void debug String msg System out println msg j public void isldle boolean idleFlag idleFlag idleFlag if idleFlag btnStart setEnabled true btnStop setEnabled false else btnStart setEnabled false btnStop setEnabled true public void patrolStopped btnStop setEnabled false btnStart setEnabled true public static void main String args UserlnterfaceSubSystem dialog new UserlnterfaceSubSystem Daniel Egido S nchez de Vega Section II Source Code ROBOT PATROL SYSTEM 196 dialog setVisible true THREE EE EEEE E BMMEMEEE E FEF A DE package guiutil RobotPatroSubSystem public class Protocol public static final int PROTOCOL_DUMMY 999 public static final int PROTOCOL CLOSECONNECTION 000 public static final int PROTOCOL STARTPATROL 100 public static final int PROTOCOL STOPPATROL 200 public static final int PROTOCOL PATROLSTOPPED 300 public static final int PROTOCOL DEBUG 400 public static final int PROTOCOL RESULTOK 800 public static final int PROTOCOL RESULTERROR 900 public static
107. n readValue For LEGO sensor values typically range from 145 dark to 890 sunlight Returns Value as raw normalized 0 to 1023 10 6 calibrateLow public void calibrateLow call this method when the light sensor is reading the low value used by readValue 10 7 calibrateHigh public void calibrateHigh Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 231 call this method whtn the light sensor is reading the high value used by reaeValue 10 8 setLow public void setLow int low set the normalized value corresponding to readValue 0 Parameters low the low value 10 9 setHigh public void setHigh int high set the normalized value corresponding to readValue 100 Parameters high the high value 10 10 getLow public int getLow return the normalized value corresponding to readValue 0 10 11 getHigh public int getHigh return the normalized value corresponding to readValue 100 11 lejos nxt Class Motor Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 232 java lang Object L lejos nxt BasicMotor L lejos nxt Motor public class Motor extends BasicMotor Abstraction for a NXT motor Three instances of Motor are available Motor A Motor B and Motor c To control each motor use methods forward backward reverseDirection stop and f1t To set each motor s speed use setSpeed Speed is in degrees per s
108. natives which are based on the environment characteristics The first environmental change possible is to modify the obstacle s corner It must transform the corner from concave into convex in the interested angle that is bending the corner As the obstacles are made of hard paper it is easy to make So it would be able already to measure the distance to the limit of the obstacle Daniel Egido S nchez de Vega 34 Section I Report ROBOT PATROL SYSTEM Figure 19 Enabling for bounds measurement This resolution will only work while the robot is approaching the obstacle in a suitable distance to face the bound in the correct angle that is right angle which will always happen as the robot is ordered to stop at the same distance quite close when approximating to the obstacle Experimentally all kind of situations occurred Sometimes working and Daniel Egido S nchez de Vega 35 Section I Report ROBOT PATROL SYSTEM sometimes not due to some factors such as the already mentioned considerable imprecision of the sensors and wheels which induced the robot stopped in a wrong distance from the obstacle and not turning the exactly angle requested while sensing the obstacle perimeter Other aspect to change would be to choose another material for environment construction The obstacles were built with white hard paper so it searched for a type of hard paper more granulated so that the grains in the su
109. nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 130 rl true waylength overcome get travel long overcome GoAround waylength rl n i 0 if I clearway false amp amp r_clearway false if overcome get_l_truehole true amp amp overcome get_r_truehole true overcome Analyze if overcome get_r_last_bound lt overcome get_ _last_bound rl true waylength overcome get_r_travel_long Jelse rl false waylength overcome get travel long j overcome GoAround waylength rl n i 0 if overcome get truehole true amp amp overcome get r truehole false rl false waylength overcome get travel long overcome GoAround waylength rl n i 0 if overcome get_l_truehole false amp amp overcome get_r_truehole true rl true waylength overcome get travel long Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 131 overcome GoAround waylength rl n i 0 if overcome get_l_truehole false amp amp overcome get_r_truehole false overcome Return overcome Retry i while i 0 amp amp i lt 3 if i gt 2 pilot stop total total overcome get d Jelse total int pilot getTravelDistance j while n lt 4 total lt 300 Sound beepSequence LCD clear LCD drawString dist 0 0
110. nds Let s call the direction of our robot at the entrance North and the other directions follow the usual convention The current direction will be held in a variable called MyDir For each direction must be assigned a number to define it North O West 1 South 2 East 3 It needs also to know which direction is to the left or right of Dir static void Left_of int dir LeftOf dir 1 4 Daniel Egido Sanchez de Vega 75 Section I Report ROBOT PATROL SYSTEM j static void Right of int dir if dir North RightOf East lelse RightOf 1 Moving one maze unit forward that is one cell corresponds to moving one position that means changing the robot position in the map by 1 The map is stored in a variable called Map which holds a value between 0 and 3 for each maze position Value 0 This corresponds to a map position which it did not visit or those which it cannot reach at all Value 1 This corresponds to a position which we ve passed already in addition it has already tried all possible routes emerging Value 2 This corresponds to a position which it is already visited but from which it have not tested yet one emerging route For example coming at a T intersection it needs to choose one path The other path is still unvisited so it must mark this position in the map with a value of 2 Value 3 This corresponds to a position in which two emerging
111. ne of the drive wheels became in any time without contact with the ground otherwise the differential would find the way of least resistance and consequently it would transfer all the power to that wheel and finally the result would be in the wheel spinning and the robot getting immobilized Daniel Egido Sanchez de Vega E zi x 21 Section I Report ROBOT PATROL SYSTEM 22 If the wheel axle is connected to an extra common axle with a elements such pulleys and belts a limited slip differential would help reduce this problem Usually the belts keep the driven axles rotating at the same velocity however during turns they slip a little on their pulleys and so allowing the wheel to adjust their speeds If a wheel get lost the contact with the floor the belts will still be able to transfer a part of power to the other wheel Figure 12 A limited slip differential Ref DAMG07 Daniel Egido S nchez de Vega A Section I Report ROBOT PATROL SYSTEM Synchro Drive A synchro drive uses three or more wheels all of them driven and steering All wheels turn together in synchronization always remaining parallel thus the robot changes its direction of movement without having to change its orientation The most important thing in order to make a 360 degree synchro drive and be able to avoid all limitations in its capacity to turn is to transfer motion along the pivoting axle of each wheel The easiest approach implies a spec
112. nt x2 150 int y2 150 voyager LeastX x2 y2 do wayfinder Evasion while wayfinder get_total lt x2 if y2 gt y1 actuator rotate 90 do wayfinder Evasion while wayfinder get total x2 y2 yelse if y2 lt y1 actuator rotate 90 do wayfinder Evasion while wayfinder get total x2 y2 if wayfinder get total x2 y2 if overcome get_part 0 voyager WayCorrection if overcome get_part 0 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 j j Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM Jelse actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 Daniel Egido Sanchez de Vega 145 Section III Source Code ROBOT PATROL SYSTEM 146 AB THE LEAST Y Sensing idem Actuator idem Obstacle idem Avoid idem EvasiveBot idem AB_LeastY TEE EH EHE EHE HE EE HE EHE EHE EE HE EE EHE EE HE A A import lejos navigation Pilot import lejos nxt public class AB leastY static AB leastY voyager new AB leastY static EvasiveBot wayfinder new EvasiveBot static Obstacle obs new Obstacle static Avoid overcome new Avoid static Actuator actuator new Actuator static Sensing sensing new Sensing static UltrasonicSensor us1 new UltrasonicSensor SensorPort S f static Ultrasoni
113. o plan again the algorithm Anyway though some of the applications seemed simple other ones were developed with much sophistication by providing new possible and alternative ways to get the goals After all the put in practice obtained considerable results with some interesting conclusions and consequences and a adequate level of efficacy So it consider in general terms to have achieved the objectives requested even more satisfactory if it takes into account that it started from the very beginning without previous knowledge about Lego robotics technology Eclipse workspace tool JAVA object oriented programming and so on That is why it appreciates and assesses at great level all learnt during the development of this project Daniel Egido S nchez de Vega 89 Section I Report ROBOT PATROL SYSTEM CHAPTER 5 FUTURE DEVELOPMENTS This project is focus on a quite opened subject as it is robot navigation so depending on as it is conceived it might add and include many kind of different applications being these approached by a wide range of ways Assuming possible improvements only about the software and not about the hardware which could also be treated though then it can as modify and improve the algorithms here exposed and explained as add totally new ones In the first option it could try to figure out a new approaching for obstacle avoidance with an intermediate level of difficulty and maybe without
114. ollowing wall does not work Nest a couple of maze samples are shown for understanding Daniel Egido Sanchez de Vega 81 Section I Report ROBOT PATROL SYSTEM 82 MN EN uu Figure 54 Maze with inner way out Figure 55 Maze with loops The exit is inside Ref DAMG07 Daniel Egido Sanchez de Vega Section I Report ROBOT PATROL SYSTEM INTERFACE FOR ROBOT PATROL SYSTEM As explained at the beginning this subsection is an extra tool for the original objective of this project It is about controlling or just ordering the robot to do something via Bluetooth communication from a computer with a developed interface This application has been developed starting from a planned pattern due to the complexity underlying this program which requires a higher level of JAVA knowledge The program is divided in two main sections One is which will be downloaded in the robot RPS NXT it contains the behavior the navigation that is the method with which the robot know its own position and orientation and the appropriated application Bluetooth enabled for the reception of the instructions The other one is which will be hold by the computer RPX GUI enabling and activating the Bluetooth communication with the robot and supporting it and the interface that the user can manage and with which can control the robot Due to having programmed this application starting from a pattern it can observe clearly the re
115. on I Report ROBOT PATROL SYSTEM Evasive Robot Evasivebot This is the first algorithm programmed and it is also the most sophisticated so it could not be tried because of the limitations of Lego robot but here it is going to be explain because it is considered interesting enough and it would be possible to implement in a higher quality robot more suitable and versatile It can say that this algorithm try to get the minimum distance between two points whose trajectory is covered by a series of obstacles And as the robot never knows the environment in advance at first it will try to get straight by surrounding the appeared obstacles on the way of following the straight trajectory after avoidance As for the obstacles it has to mention that there are some restrictions in order to be the robot successful in its behavior All obstacles used in this application must be squared like that is having right angles such as squares rectangles and similar ones in different longitudes and sizes Daniel Egido Sanchez de Vega 29 Section I Report ROBOT PATROL SYSTEM 30 ep pus o Figure 14 Variable shaped obstacles Figure 15 Squared Obstacles Avoidance Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM al And it is not the only important restriction because another basic factor is the obstacle has to be perfectly pulled out in front of the facing robot That means perpendicular to t
116. onent createNXTNamelnputPane JPanel panel new JPanel cName new JTextField DANIMASTER 5 panel setLayout new FlowLayout panel add new JLabel NXT Conlnfo panel add new JLabel Name panel add cName return panel private Component createNXTAddressinputPane JPanel panel new JPanel lcAddress new JTextField 001653039bb0 12 cAddress new JTextField 00165302809a 12 panel setLayout new FlowLayout panel add new JLabel Address panel add cAddress return panel private Component createButtonPane JPanel panel new JPanel BoxLayout layoutManager new BoxLayout panel BoxLayout X AXIS btnConnect new JButton btnDisconnect new JButton btnStart new JButton btnStop new JButton panel setLayout layoutManager panel add Box createHorizontalGlue panel add btnConnect panel add btnDisconnect panel add btnStart panel add btnStop pe btnConnect addActionListener this Daniel Egido S nchez de Vega 192 Section III Source Code ROBOT PATROL SYSTEM 193 btnDisconnect addActionListener this btnConnect setT ext Connection btnDisconnect setText Disconnection btnDisconnect setEnabled false btnStart addActionListener this btnStop addActionListener this btnStart setText Patrol btnStop setText STOP btnStart setEnabled false btnStop setEnabled false return panel PatrolA
117. ons The other aspect more relevant is that the total distance to travel is the calculated one plus the robot length as minimum Figure 25 Total travel distance Analogously when the robot is facing the obstacle s side wall it estimates the distance to travel thought this time could be more efficient faster to travel a certain length and check if the wall is finished or it must go on Daniel Egido S nchez de Vega 41 Section I Report ROBOT PATROL SYSTEM i Figure 26 Travelling side wall Before deciding a suitable distance to face the obstacle and a basic angle with which turn and check repeatedly it did a little theoretical study to find out if the relation distance angle is appropriated to be chosen for practice and calculus After trying with some different numbers it was chosen 5cm distance and an angle of 10 Daniel Egido S nchez de Vega 42 Section I Report ROBOT PATROL SYSTEM 43 1o SI s o8 0 23 Lo 5 S av orau 18 l A 08 au Figure 27 Calculating each shot separately When the robot performs the calculus is directly did and just the last and useful data is overwritten and saved but now it is doing step by step solving each triangle separately with 10 angle and an original distance of 5 cm which is the side of the first triangle but of course is different when facing the next ones so it must base calculations in the previous trian
118. or speed 200 while sensing distance us2 gt 10 amp amp sensing distance us2 actuator speed 200 Motor B setSpeed 210 void keepRdistance actuator go actuator speed 200 while sensing distance us3 gt 10 amp amp sensing distance us3 actuator speed 200 Motor A setSpeed 210 void WayCorrection int di 0 int d2 0 int d3 0 if overcome get_part 1 yi Section HI Source Code ROBOT PATROL SYSTEM 142 actuator counter while sensing distance us3 25 voyager keepRdistance d1 actuator distance actuator rotate 90 actuator counter while sensing distance us3 lt 25 voyager keepRdistance d2 actuator distance if d2 gt overcome get l1 actuator rotate 90 actuator counter while sensing distance us3 lt 25 voyager keepRdistance d3 actuator distance if d3 gt 2 d1 actuator stop LCD clear LCD drawString no way 0 0 Jelse actuator rotate 90 actuator travel d2 overcome get 11 actuator rotate 90 actuator travel d1 d3 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 j Jelse actuator rotate 90 actuator travel d1 actuator rotate 90 actuator travel overcome get l1 d2 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 if overcome get_part
119. ot does know the environment layout by having a file in its memory or by mapping Thus the performance is easier and the robot can be focus more strongly in the hunting strategy or prey escape However as the robot has to deal continuously with new and unexpected obstacles it has to take the useful obstacle avoidance algorithm and later it must implement any strategy for hunting which runs according to the hunting process that is they have to have a good level of compatibility each other in order to obtain a efficient robot behavior in managing the environment while pursuing its target Regarding the rules as simple as above mentioned the environment is full of obstacles and the hunter has to find the Daniel Egido S nchez de Vega 60 Section I Report ROBOT PATROL SYSTEM 61 prey and pursue it until catching that will be considered as a result over 85 in the signal reception of the light sensor then the hunter wins But if the hunter does not find or get lost his target as surely the prey would get the initial point hunter exit Thus the process and features are as follow Firstly talking about the strategy and behavior it chose a motion prowling like That is in this case shown through a kind of zigzag performance It had to look for and decide how the hunter would search for the prey without knowing the environment and without leaving in the open the exit point where the prey can be saved and become winner
120. ot will be the background for other algorithms which take advantage of this basis In this case of avoiding obstacles the environment is quite simple just the obstacles their selves However the suspected too simplicity is due to the restrictions of the obstacles it is detailed later Following with the same background it has developed a trial of Hunter behavior game which it has not been put in practice because of lack of resources and other difficulties Later a couple of Line Followers were developed and tried with excellent results Although might be a quite simple target to accomplish it considered mandatory to carry it out as it is a fundamental application for any robotics fan Moreover it is regarded as other kind or environment where the robot has know how to manage successfully fulfill its objective The next step was to program a method for maze application where the robot has to find the way out in a determined labyrinth It is Daniel Egido S nchez de Vega 27 Section I Report ROBOT PATROL SYSTEM another typical example of application for mobile robotics but in this case it has made a different approach Finally it decided to go a little beyond the original purpose by adding a complementary tool for this whole patrol system For that it developed a program with which it can control the robot from the computer with a interface by Bluetooth communication Daniel Egido Sanchez de Vega 28 Secti
121. public void stopPatrol server debug stopPatrol called RPC stopPatrol Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 167 public static void main String args RPSSystem rpsSystem new RPSSystem rpsSystem start HHHHHHHH H H H H H H H H H H H H H package Constants public class Event public static final int EMPTY 0 public static final int START PATROL 1 public static final int SETTING 2 public static final int GET DIRECTION 70 public static final int D RECTION 5 public static final int TURN DIRECTION 6 public static final int TURNED 7 public static final int START 8 public static final int STARTED 9 public static final int STARTING 10 public static final int AFTER ELAPEDTIME 14 public static final int READ_SENSORDATA 15 public static final int SENSORDATA 16 public static final int CHECK_INTRUSION 17 public static final int NO NTRUSION 18 public static final int GET CURRPOSITION 19 public static final int CURRPOSITOIN 20 public static final int 5 ARRIVED 21 public static final int NO_DESTINATION 22 public static final int YES DESTINATION 23 public static final int YES NTRUSTION 24 public static final int STOP 1 25 public static final int STOP 2 26 public static final int STOP 3 27 public static final int STOPPED NOINTRUTION YESDESTINATION 28 HT I Daniel Egido S nchez de Veg
122. r int ping Send a single ping int reset Reset the device Performs a soft reset of the device int sendData int register byte buf int len Executes an I2C write transaction int setCalibrationData byte data Set3 bytes of calibration data int setContinuousInterval byte interval Set the ping inetrval used when in continuous mode Methods inherited from class lejos nxt I2CSensor fetchString getPort getProductID getSensorType getVersion sendData setAddress Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 221 Methods inherited from class java lang Object clone equals finalize getClass hashCode notify notifyAll toString wait wait wait Constructor Detail 9 1 UltrasonicSensor public UltrasonicSensor I2CPort port Method Detail 9 2 getData public int getData int register byte buf int len Description copied from class 12CSensor Executes an I2C read transaction and waits for the result Overrides getData in class I2CSensor Parameters register 2C register e g 0x41 buf Buffer to return data len Length of the return data Returns status 0 success 0 failure 9 3 sendData public int sendData int register byte buf Daniel Egido Sanchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 222 int len Description copied from class 12cSensor Executes an I2C write transaction
123. r void setSpeed int speed Sets motor speed in degrees per second Up to 900 is possible with 8 volts void shutdown causes run to exit void smoothAcceleration boolean yes enables smoother acceleration void stop Causes motor to stop pretty much instantaneously Methods inherited from class lejos nxt BasicMotor isBackward isFloating isForward isStopped Methods inherited from class java lang Object clone equals finalize getClass hashCode notify notifyAll toString wait wait wait Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 237 Field Detail 11 1 port public TachoMotorPort port 11 2 regulator public Motor Regulator regulator 11 3 rampUp public boolean rampUp set by smoothAcceleration forward backward setSpeed Only has effect if regulate is true 11 4A public static final Motor A Motor A 11 5 B public static final Motor B Motor B 11 6 C public static final Motor C Motor C Constructor Detail Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 238 11 7 Motor public Motor TachoMotorPort port Use this constructor to assign a variable of type motor connected to a particular port Parameters port to which this motor is connected Method Detail 11 8 getStopAngle public int getStopAngle 11 9 forward public void forward Causes motor to
124. ravelDistance void counter pilot resetTachoCount void rotate int angle pilot rotate angle void speed int speed pilot setSpeed speed void travel int d pilot travel d void stop pilot stop EE HE E EE HERE EE EHE EE E EE EH RR RR B ET import lejos navigation Pilot import lejos nxt Motor import lejos nxt SensorPort import lejos nxt UltrasonicSensor public class Avoid first try to avoid turning right static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C static UltrasonicSensor us new UltrasonicSensor SensorPort S 1 static Obstacle obs new Obstacle Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 123 static Actuator actuator new Actuator static Sensing sensing new Sensing boolean clearway Arue robot can avoid obstacle by the right int l1 0 int I2 0 try to avoid the obstacle by the right boolean TurnRight actuator rotate 90 if sensing distance us 255 clearway false Jelse clearway true return clearway try to avoid obstacle by the left boolean TurnLeft actuator rotate 90 if sensing distance us 255 clearway false Jelse clearway true return clearway backwards void Retry while sensing distance us obs get_dis 5 actuator back actuator stop Turn back Repositioning void Return Go around t
125. rface had the function of deviate the sensor ray in order to go back The more granulated surface the more possibilities the rays go back to the receiver However the granulated hard paper found it was not good enough as the grains were not big and numerous enough so the trials did not work After all it is a hard paper But the idea is worth to be considered in future applications Figure 20 Obstacle s granulated surface Daniel Egido S nchez de Vega 36 Section I Report ROBOT PATROL SYSTEM Figure 21 Granulated hard paper The last resulting possibility is just the opposite to use a polished material so is able for the maximum reflection possible for example in this case the aluminum when polished is a good option or just a mirror With the maximum rate of reflection it is increasing the possibility percentage to receive back the signal It should combine this option with another one as the burst infrared sensor In this case the obstacles bound should not be allocated too far from the robot sensing as if the angle formed in the corner between the surface and the robot is extremely narrow it will be impossible to measure In the experiments without any combination with other alternative did not work Daniel Egido S nchez de Vega 97 Section I Report ROBOT PATROL SYSTEM Figure 22 Robot dealing with mirror type obstacle Eventually it can claim the first option is the most appropriate
126. rrently in motion 11 16 rotate public void rotate int angle causes motor to rotate through angle Parameters angle through which the motor will rotate 11 17 rotate public void rotate int angle boolean immediateReturn causes motor to rotate through angle iff immediateReturn is true method returns immediately and the motor stops by itself If any motor method is called before the limit is reached the rotation is canceled When the angle is reached the method isRotating returns false Parameters angle through which the motor will rotate immediateReturn iff true method returns immediately thus allowing monitoring of sensors in the calling thread Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 241 11 18 rotateTo public void rotateTo int limitAngle causes motor to rotate to limitAngle Then getTachoCount should be within 2 degrees of the limit angle when the method returns Parameters limitAngle to which the motor will rotate 11 19 rotateTo public void rotateTo int limitAngle boolean immediateReturn causes motor to rotate to limitAngle if immediateReturn is true method returns immediately and the motor stops by itself and getTachoCount should be within 2 degrees if the limit angle If any motor method is called before the limit is reached the rotation is canceled When the angle is reached the method isRotating returns false Parameter
127. s limitAngle to which the motor will rotate and then stop immediateReturn iff true method returns immediately thus allowing monitoring of sensors in the calling thread 11 20 shutdown public void shutdown causes run to exit Daniel Egido Sanchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 242 11 21 regulateSpeed public void regulateSpeed boolean yes turns speed regulation on off Cumulative speed error is within about 1 degree after initial acceleration Parameters yes is true for speed regulation on 11 22 smoothAcceleration public void smoothAcceleration boolean yes enables smoother acceleration Motor speed increases gently and does not lt gt overshoot when regulate Speed is used 11 23 setSpeed public void setSpeed int speed Sets motor speed in degrees per second Up to 900 is possible with 8 volts Parameters speed value in degrees sec 11 24 setPower public void setPower int power sets motor power This method is used by the Regulator thread to control motor speed Warning negative power will cause the motor to run in reverse but without updating the direction field which is used by the Regulator thread If the speed regulation is enabled the results are unpredictable Overrides Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 243 setPower in class BasicMotor Parameters power power setting 0 100 11 2
128. s for turnRate are between 200 and 200 The turnRate determines the ratio of inner wheel speed to outer wheel speed as a percent Formula ratio 100 abs turnRate When the ratio is negative the outer and inner wheels rotate in opposite directions Examples e steer 25 gt inner wheel turns at 75 of the speed of the outer wheel Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 214 e steer 100 gt inner wheel stops e steer 200 gt means that the inner wheel turns at the same speed as the outer wheel a zero radius turn Note Even if you have specified a drift correction in the constructor it will not be applied in this method Parameters turnRate If positive the left wheel is on the inside of the turn If negative the left wheel is on the outside angle The angle through which the robot will rotate If negative robot traces the turning circle backwards immediateReturn If immediateReturn is true then the method returns immediately and your code MUST call updatePostion when the robot has stopped Otherwise the robot position is lost 7 21 turn void turn float radius Moves the NXT robot in a circular path with a specified radius The center of the turning circle is on the right side of the robot if parameter radius is negative Postcondition Motor speeds are unpredictable Parameters radius of the circular path If positive the left wheel is on t
129. s us Figure 48 Maze scheme divided in cells Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM Figure 49 Real Maze Above it can see the result of the maze construction Cells are 25x25 cm as the design requires However in the experiments appeared a problem the measurements are a little tight so sometimes when the robot has to turn or it is just a little deviated it gets crashed the walls and then cannot turn all ordered degrees or it just keeps blocked Apart from that the performance is quite good showing a efficient behavior representative of the program algorithm All curves are supposed right angled so every turn should be perfectly corresponding to but the friction with the hard paper and the tight corridor cause bad turns so the robot many times must be corrected manually in order to go on the way Daniel Egido S nchez de Vega E Y RY 74 Section I Report ROBOT PATROL SYSTEM The maze solver robot always advances step by step that is cell by cell so it travels 25 cm and checks the three directions right front left with the three ultrasonic sensors in order to decide the next step Figure 50 some maze paths Next it is going to explain about the Tremaux s algorithm and its technique for programming and to understand how it works First it must define four directions north west south and east These directions do not have to coincide with the actual four wi
130. sMoving Returns true if the robot is moving under power 7 5 setMoveSpeed void setMoveSpeed float speed Sets the movement speed of the robot Parameters speed The speed in wheel diameter units per second 7 6 getMoveSpeed float getMoveSpeed Returns the movement speed of the robot in wheel diameter units per second Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 209 7 7 getMoveMaxSpeed float getMoveMaxSpeed Returns the maximal movement speed of the robot in wheel diameter units per second which can be maintained accurately Will change with time as it is normally dependent on the battery voltage 7 8 setTurnSpeed void setTurnSpeed float speed Sets the turning speed of the robot Parameters speed The speed in degree per second 7 9 getTurnSpeed float getTurnSpeed Returns the turning speed of the robot in degree per second 7 10 getTurnMaxSpeed float getTurnMaxSpeed Returns the maximal turning speed of the robot in degree per second which can be maintained accurately Will change with time as it is normally dependent on the battery voltage Daniel Egido Sanchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 210 7 11 setSpeed void setSpeed int speed Deprecated in 0 8 use setTurnSpeed and setMoveSpeed The method was deprecated as this it requires knowledge of the robots physical construction which this in
131. so many limitations and restrictions about environment design characteristics Even it could develop an expansion of this algorithm by improving the program to able the robot to avoid mobile obstacle that is obstacles in motion that would be a step closer the real life as the robot could manage people moving in a room for instance Other example might be to try new methods for maze solver Daniel Egido S nchez de Vega 90 Section I Report ROBOT PATROL SYSTEM different ways of which mentioned in this project as many strategies can be made up and applied Regarding adding new algorithms it could change the reference system that is in this project the robot considers itself always as the absolute reference from its position everything is determined but it could change to a external reference system by using for example a series of sensors spread and allocated in the environment with that it could apply a GPS method for robot positioning and localization Or even if being available more sophisticated resources it could allocate some Bluetooth devices along the environment whose signals sent to the robot might be clues for it in order to know the position or just meaning instructions for the next steps and so on In short a patrol system is a large field in which can be considered many interesting and diverse applications A worthy challenge to deep in robotics Daniel Egido S nchez de Vega 91 Section I R
132. sulting source code is more structured and schematized it is divided in more sections and subsections taking a clser appearance to JAVA programming formalized style Daniel Egido S nchez de Vega 83 Section I Report ROBOT PATROL SYSTEM But not only in appearance but also in the code quality as it is required a more advanced understanding of JAVA it having learnt new programming concepts such as EVENT or LISTENER which make possible to achieve this application to be developed The RPS NXT is divided in some groups containing the sensing system the actuators the server some utilities and useful datas The RPS GUI is composed of some folders with the interface system some protocol and listener After downloading the first one to the Lego robot the second one must be run as a JAVA application for that it selects the main file called UserlnterfaceSubSystem and it executes It is shown in the next figure Daniel Egido S nchez de Vega 84 Section I Report ROBOT PATROL SYSTEM Java UserlnterfaceSubSystem java Eclipse SDK LOG File Edit Source Refactor Navigate Search Project Run Window Help ri l 31 0 Q BEG a Ser E amp Java I Package Explorer 53 Hierarchy El 1 Obstacle java 7 PathFinder java D UserinterfaceSub 52 m e 053 E package gui lal 7 4 AB leastX a X ri e Essv voldane import guiutil rpsa RobotPatrolSystemAgent B awe 2 Line
133. synchronized syncObj writeDummy dos writelnt Protocol PROTOCOL RESULTOK dos flush else synchronized syncObj writeDummy dos writelnt Protocol PROTOCOL RESULTERROR dos flush catch IOException e LCD clear LCD drawString e getMessage 0 0 btc closeStream btc close Daniel Egido Sanchez de Vega Section II Source Code ROBOT PATROL SYSTEM private void readDummy throws IOException dis readint dis readint dis readint private void write Dummy throws IOException synchronized syncObj dos writelnt Protocol PROTOCOL DUMMY dos writelnt Protocol PROTOCOL DUMMY dos writelnt Protocol PROTOCOL DUMMY public void patrolStopped try synchronized syncObj writeDummy dos writelnt Protocol PROTOCOL PATROLSTOPPED dos flush catch Exception e LCD clear LCD drawString 1 e getMessage 0 0 bolaj String param msg public void debug String msg try synchronized syncObj writeDummy dos writelnt Protocol PROTOCOL DEBUG dos writelnt msg length Daniel Egido Sanchez de Vega 188 Section HI Source Code ROBOT PATROL SYSTEM 189 dos writeChars msg dos flush catch Exception e LCD clear LCD drawString 1 e getMessage 0 0 public void isldle boolean idleFlag try synchronized syncObj writeDummy dos writelnt Protocol PROTOC
134. t getMoveMaxSpeed float getMoveSpeed float getTravelDistance a float getTurnMaxSpeed A22 float getTurnSpeed boolean isMoving void reset Reset traveled distance and rotated angle _ _ __ void rotate float angle Rotates the NXT robot a specific number of degrees in a direction deka Daniel Egido Sanchez de V ty anie O anchez ae veea LON de 5 5 Saga Section IV Datasheets ROBOT PATROL SYSTEM 206 void rotate float angle boolean immediateReturn Rotates the NXT robot a specific number of degrees in a direction void setMoveSpeed float speed Sets the movement speed of the robot void setSpeed int speed Deprecated in 0 8 use setTurnSpeed and setMoveSpeed The method was deprecated as this it requires knowledge of the robots physical construction which this interface should hide void setTurnSpeed float speed Sets the turning speed of the robot void steer int turnRate Moves the NXT robot in a circular path at a specific turn rate void steer int turnRate int angle Moves the NXT robot in a circular path at a specific turn rate void steer int turnRate int angle boolean immediateReturn Moves the NXT robot in a circular path at a specific turn rate void stop Halts the NXT robot and calculates new x y coordinates void travel float distance Moves the NXT robot a specific distance voi
135. t end y return int Math toDegrees Math atan2 end_y start y end x start x 90 EE ERE HE HERE EE EHE HE E EE E RH RR RR package rpss utilities public class IntrusionDetector public IntrusionDetector public boolean checklntrusion int distance if distance 15 return true else return false Daniel Egido S nchez de Vega EN Y Section III Source Code ROBOT PATROL SYSTEM 174 PAR o EEEEEBEPRE BESSE package rpss utilities import rpss data Range public class PatrolRange private int distance private Range R public PatrolRange Range R_ R R public void setRange int x int y R start x 0 R start_y 0 R end x x R end_y y distance int Math sqrt R start_x R end x R start x R end_x R start y R end y R start y R end y public boolean isArrived int distance if distance gt distance return true else return false public int thisdistance return distance j public void updateRange int temp temp R start_x R start_x R end_x R end_x temp temp R start_y R start_y R end_y R end_y temp p er p pepe dep deep deep dede ede der package rpss utilities import rpss data TrueFalse import lejos util Timer import lejos util TimerListener Daniel Egido S nchez de Vega Section II Source Code ROBOT PATROL SYSTEM 175 E Every 50ms PatrolTimer class set the variable flag of
136. t light read Value 3 9 0 LCD refresh Thread s eep 100 Stop car gently with free wheel drive MotorPort B controlMotor 0 flt MotorPort C controlMotor 0 flt LCD clear LCD drawString Program stopped 0 0 LCD refresh Thread s eep 1000 TREMAUX MAZE SOLVER Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 159 Sensing Idem Actuator Idem Solver TEE EH EHE EHE HE EHE He EHE EE EHE EHE EHE EE EHE EE RR import lejos nxt SensorPort import lejos nxt UltrasonicSensor public class Solver static UltrasonicSensor us1 new UltrasonicSensor SensorPort S f static UltrasonicSensor us2 new UltrasonicSensor SensorPort S2 static UltrasonicSensor us3 new UltrasonicSensor SensorPort S3 static Actuator actuator new Actuator static Sensing sensing new Sensing Direction Mydir 2 new Direction static int MyDir define the directions in space static int North 0 static int West 1 static int South 2 static int East 3 static int eftOf static int RightOf relative positions static int RelPosX static int RelPosY Size of maze map static int SizeX 10 static int SizeY 10 static int Map new int SizeX Size Y 0 position which is not visited or cannot be visited Vi position whose all ways are tried 112 position already visited but one way not tried 3 position already visited but two
137. t travel travel long pilot rotate 90 if rl true pilot rotate 90 pilot travel travel long pilot rotate 90 sf Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 116 pilot resetTachoCount tachometer reset pilot setSpeed 200 fix speed while us2 getDistance 255 pilot forward pilot travel 25 d int pilot getTravelDistance pilot rotate 90 pilot travel travel long pilot rotate 90 j pilot stop TTT EHE HEHE EE EHE HE EE E EE EHE Es A A A import lejos navigation Pilot import lejos nxt UltrasonicSensor import lejos nxt import lejos nxt LCD import lejos nxt Motor public class EvasiveBot static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C wheel diameter trackwidth leftmotor rightmotor static UltrasonicSensor us1 new UltrasonicSensor SensorPort S7 static UltrasonicSensor us2 new UltrasonicSensor SensorPort S2 static UltrasonicSensor us3 new UltrasonicSensor SensorPort S3 static Obstacle obs new Obstacle static Avoid overcome new Avoid static String dist distance static String unit unit public static void main String args int i 0 attempts counter int n 0 avoided obstacles counter boolean r_clearway true robot can avoid obstacle by the right side boolean _clearway true robot can avoid obstacle by the left side int waylength 0 length of
138. tSpeed 210 pilot setSpeed 200 void WayCorrection int di 0 int d2 0 int d3 0 if overcome get_part 1 MN Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 133 pilot resetTachoCount while us3 getDistance lt 25 voyager keepRdistance j d1 int pilot getTravelDistance pilot rotate 90 pilot resetTachoCount while us3 getDistance lt 25 voyager keepRdistance d2 int pilot getTravelDistance if d2 gt overcome get travel long pilot rotate 90 pilot resetTachoCount while us3 getDistance lt 25 voyager keepRdistance j d3 int pilot getTravelDistance if d3 gt 2 d1 pilot stop LCD clear LCD drawString no way 0 0 Jelse pilot rotate 90 pilot travel d2 overcome get travel long pilot rotate 90 pilot travel d1 d3 pilot stop Sound beepSequence LCD clear LCD drawString Destination 0 0 Jelse pilot rotate 90 pilot travel d1 pilot rotate 90 pilot travel overcome get travel long d2 pilot stop Sound beepSequence LCD clear LCD draweString Destination 0 0 j if overcome get_part 2 Daniel Egido Sanchez de Vega Section III Source Code ROBOT PATROL SYSTEM 134 pilot stop Sound beepSequence LCD clear LCD drawString Destination 0 0 if overcome get_part 3 pilot resetTa
139. taOutputStream dos public RobotPatrolSystemServerListener getListener return listener jx x param listener public void setListener RobotPatrolSystemServerListener listener l this listener listener pes Bluetooth Connection public void startServer RPCoordinator RPC Daniel Egido Sanchez de Vega Section III Source Code ROBOT PATROL SYSTEM 186 while true LCD clear LCD drawString Server Started 0 0 btc Bluetooth waitForConnection LCD clear LCD drawString Client Connected 0 0 try dis btc openDatalnputStream dos btc openDataOutputStream RPC timer start while true readDummy int command dis readlnt if command Protocol PROTOCOL_CLOSECONNECTION btc closeStream btc close break if command Protocol PROTOCOL_STARTPATROL int x dis readlnt int y dis readint if listener null test listener startPatrol x y synchronized syncObj writeDummy dos writelnt Protocol PROTOCOL RESULTOK dos flush LCD clear LCD drawString Start Patrol 0 0 Daniel Egido Sanchez de Vega Section II Source Code ROBOT PATROL SYSTEM 187 else synchronized syncObj writeDummy dos writelnt Protocol PROTOCOL RESULTERROR dos flush else if command Protocol PROTOCOL_STOPPATROL if listener null listener stopPatrol
140. taining the results The getDistance call automatically takes care of this The normal getDistance call may also be used with ping returning information for the first echo Calling this method will disable the default continuous mode to switch back to continuous mode call continuous Returns 0 if ok 0 otherwise 9 7 continuous public int continuous Switch to continuous ping mode This method enables continuous ping and capture mode This is the default operating mode of the sensor Please the notes for ping for more details Returns 0 if ok 0 otherwise Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 224 9 8 off public int off Turn off the sensor This call disables the sensor No pings will be issued after this call until either ping continuous or reset is called Returns 0 if ok 0 otherwise 9 9 capture public int capture Set capture mode Set the sensor into capture mode The Lego documentation states Within this mode the sensor will measure whether any other ultrasonic sensors are within the vicinity With this information a program can evaluate when it is best to make a new measurement which will not conflict with other ultrasonic sensors I have no way of testing this Perhaps someone with a second NXT could check it out Returns 0 if ok 0 otherwise 9 10 reset public int reset Reset the device Performs a soft reset of the device
141. te STOPPING return Event STOP 2 j else if state State READING SENSOR if event Event SENSORDATA state State CHECKING INTRUSION return Event CHECK INTRUSION else if event Event STOP_PATROL state State STOPPING return Event STOP_2 else if state State CHECKING INTRUSION if event Event NO_INTRUSION state State LOCALIZING return Event GET CURRPOSITION Daniel Egido S nchez de Vega Section III Source Code ROBOT PATROL SYSTEM 177 else if event Event STOP PATROL state State STOPPING return Event STOP 2 else if event Event YES INTRUSTION state State STOPPING return Event STOP 1 j else if state State L OCALIZING if event Event LURRPOSITOIN state State CHECKING DESTINATION return Event IS ARRIVED else if event Event STOP PATROL state State STOPPING return Event STOP 2 j else if state State CHECKING DESTINATION if event Event NO DESTINATION state State MOVING return Event EMPTY else if event Event YES DESTINATION state State STOPPING return Event STOP_3 else if event Event STOP_PATROL state State STOPPING return Event STOP 2 else if state State STOPPING M if event Event STOPPED YESINTRUSION state State ALARMING return Event ALARM else if event Event STOPPED NOINTRUSION NODEPARTED state
142. terface should hide Sets drive motor speed Parameters speed The speed of the drive motor s in degree per second 7 12 travel void travel float distance Moves the NXT robot a specific distance A positive value moves it forward and a negative value moves it backward Method returns when movement is done Parameters distance The positive or negative distance to move the robot 7 13 travel void travel float distance boolean immediateReturn Moves the NXT robot a specific distance A positive value moves it forward and a negative value moves it backward Parameters distance The positive or negative distance to move the robot immediateReturn If immediateReturn is true then the method returns immediately and your code MUST call updatePostion when the robot has stopped Otherwise the robot position is lost Daniel Egido S nchez de Vega Section IV Datasheets ROBOT PATROL SYSTEM 211 7 14 rotate void rotate float angle Rotates the NXT robot a specific number of degrees in a direction Method returns when rotation is done Parameters angle The angle to rotate in degrees A positive value rotates left a negative value right clockwise 7 15 rotate void rotate float angle boolean immediateReturn Rotates the NXT robot a specific number of degrees in a direction Method returns when rotation is done Parameters angle The angle to rotate in degrees A positive value rotat
143. the operating system You can verify this in the device manager You also need to select your main class window in the middle before starting the downloading procedure so that Eclipse knows which class you want to download Use the pull down menu denoted as 4 in the screenshot to select the downloading favorite your previously created This will start the downloading procedure After the download is complete you can start the program by using the buttons on the NXT Notice that the program will run forever To stop it you need to reset the NXT by holding the two middle buttons for a Daniel Egido Sanchez de Vega 102 Section II User Manual ROBOT PATROL SYSTEM longer time This will then terminate the USB connection so you need to wait a little for it to reconnect before you download a new program Of course there are better ways of ending your program such as listening to a button press or after a certain delay Replace the endless while loop with this try 1 Thread sleep 5000 catch InterruptedException e TODO Auto generated catch block x This will set your NXT to sleep for 5 seconds before the program ends You will now see Hello World for five seconds and then the program ends For more information on programming in Java you should check the leJOS page Daniel Egido S nchez de Vega 103 Section II Source Code ROBOT PATROL SYSTEM 104 SECTION III SOURCE CODE Daniel Egido S nchez de Vega
144. the wheels it steers a complete section of the robot The front wheels always remain parallel to the front part of the chassis and the same applies to the rear wheels in regard to the rear part of the chassis However the two parts connect through a point of articulation that lets them pivot in the middle This architecture is usual in wheeled excavators and other construction equipment Tri Star wheel drive This option has been designed for high capacity of mobility Each wheel is in reality an equilateral triangle with wheels in each vertex the robot features three of them for a total of 12 wheels The wheels turn and the triangles can also turn like larger wheels During usual movements two wheels of each triangle touch the ground but when a wheel sticks against an obstacle a complex gearing system transfers motion to the triangular structure which turns and places its upper wheel past the obstacle After having studied all these interesting structural options for building the robot and taking into account the limitation of resources and the characteristics and types of applications it is going to face it conclude that the best option with a generalist and versatile view is the Simple Differential Drive So it is which has been brought to practice Daniel Egido S nchez de Vega 25 Section I Report ROBOT PATROL SYSTEM CHAPTER 3 SOFTWARE In this chapter two different parts are involved in the software subject of
145. tion if overcome get_part 0 Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 151 actuator stop Sound beepSequence LCD clear LCD drawString Destination 0 0 Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 152 HUNTER Sensing Idem Actuator Idem Obstacle Idem Avoid Idem EvasiveBot ldem Hunter TEE EHE EHE D ERE EHE EE HE EHE EE HET EHE EE EHE EFT import lejos navigation Pilot import lejos nxt public class Hunter static Hunter predator new Hunter static EvasiveBot wayfinder new EvasiveBot static Obstacle obs new Obstacle static Avoid overcome new Avoid static Actuator actuator new Actuator static Sensing sensing new Sensing static UltrasonicSensor us1 new UltrasonicSensor SensorPort S7 static UltrasonicSensor us2 new UltrasonicSensor SensorPort S2 static UltrasonicSensor us3 new UltrasonicSensor SensorPort S3 static LightSensor ls new LightSensor SensorPort 5S4 Firstly it is assumed the initial robot position as zero and north oriented static int x7 0 initial x position static int y7 0 initial y position void LeastX int x2 int y2 if x2 gt x7 actuator rotate 90 Jelse if x2 x7 actuator rotate 90 void keepLdistance ye Sy 3 E Daniel Egido S nchez de Vega a gt Section HI So
146. tors have a different efficiency surely it may find one wheel turning a little faster than the other thus making the robot turn slightly left or right In some Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM 12 projects this isn t a problem particularly those programmed for continuous route correction such as following a line But when it wants the robot to simply go straight in an open space this can be a important problem This relevant problem may be solved by embedding encoders in the motors included in the NXT technology In a nutshell the encoders allow motor rotations to be monitored to the nearest degree This provides the way for the robot to go straight and auto correct themselves along the way Despite this new feature it is still important to understand the concepts behind differential drive mechanisms Later it is discussed alternative approaches including both the sensor based approach as well as using gears Using Servo Motor Encoders to Go Straight A more sophisticated approach that has several positive side effects requires a feedback mechanism into the system thus controlling each wheel with sensors and adjusting their speed according to the readings This is the most common way for real differential drives The only requirement is that it needs two drive motors each attached to a drive wheel Using Gears to Go Straight Daniel Egido S nchez de Vega Section I Report
147. tton btnDisconnect private JTextField cName private JTextField cAddress private JTextField xDest private JTextField yDest Daniel Egido S nchez de Vega 190 Section II Source Code ROBOT PATROL SYSTEM 191 private boolean idleFlag true public UserlnterfaceSubSystem agent new RobotPatrolSystemAgent agent setListener this initialize ES UI Control private void initialize JRootPane contentPane this getRootPane BorderLayout layoutManager new BorderLayout 10 10 contentPane setLayout layoutManager contentPane add createlnputPane BorderLayout NORTH contentPane add createButtonPane BorderLayout SOUTH this setSize 400 230 this setLocation 300 300 private Component createlnputPane JPanel panel new JPanel panel setLayout new BorderLayout 5 5 panel add createNXTNamelnputPane BorderLayout NORTH panel add createNXT DestinationInputPane BorderLayout CENTER panel add createNXTAddressInputPane BorderLayout SOUTH return panel j private Component createNXT DestinationInputPane JPanel panel new JPanel xDest new JTextField 0 5 yDest new JTextField 10 5 panel setLayout new FlowLayout panel add new JLabel X panel add xDest panel add new JLabel Y Daniel Egido S nchez de Vega Section II Source Code ROBOT PATROL SYSTEM panel add yDest return panel private Comp
148. ublic void timedOut localize Daniel Egido S nchez de Vega Section II Source Code ROBOT PATROL SYSTEM 171 public void localize EN readEncoder CP setCurrPosition int ED distance Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM package rpss data public class EncoderData public int rightcount public int leftcount public float distance public EncoderData j T av a a ERE De D Ma RE RARE RRMR RR REY package rpss data public class Range public int start x public int start y public int end x public int end y j THERE CHE HR ECHTE EEE A E EEE package rpss data public class SonarData private int distance public SonarData distance 10000 public void setDistance int d distance d public int getDistance return distance TET eA qT4 4 EEFEEEBEEEFR package rpss data public class TrueFalse public boolean flag j Daniel Egido S nchez de Vega 172 Section HI Source Code ROBOT PATROL SYSTEM 173 package rpss utilities public class CurrPosition private int distance public CurrPosition distance 0 public void setCurrPosition int dis_ distance dis public int getCurrPosition return distance EE EE RR E epopeo package rpss utilities public class DirectionCalculator public DirectionCalculator public int getDirection int start x int start y int end x in
149. ult true System out printin Exception from open dis new DatalnputStream nxtComm getlnputStream dos new DataOutputStream nxtComm getOutputStream isRunning true Thread t new Thread this t start return result Daniel Egido S nchez de Vega Section III Source Code ROBOT PATROL SYSTEM 198 public void close try isRunning false writeDummy dos writelnt Protocol PROTOCOL CLOSECONNECTION dos flush synchronized this j dis close dos close nxtComm close this wait 1000 catch Exception e System out println IOException closing connection System out printin e getMessage public boolean startPatrol int endPointX int endPointY boolean result false try writeDummy dos writelnt Protocol PROTOCOL STARTPATROL dos writelnt endPointX dos writelnt endPointY dos flush int resultMsg Integer queue take intValue if resuliMsg Protocol PROTOCOL RESULTOK result true else if resultMsg Protocol PROTOCOL_RESULTERROR result false Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 199 catch Exception e e printStackTrace j return result public boolean stopPatrol boolean result true try writeDummy dos writelnt Protocol PROTOCOL STOPPATROL dos flush int resultMsg Integer queue take intValue if
150. urce Code ROBOT PATROL SYSTEM 153 actuator go actuator speed 200 while sensing distance us2 10 amp amp sensing distance us2 actuator speed 200 lt 25 Motor B setSpeed 210 void keepRdistance actuator go actuator speed 200 while sensing distance us3 gt 10 amp amp sensing distance us3 actuator speed 200 lt 25 Motor A setSpeed 210 prey detection static void det if s readValue gt 50 Hunter Hunting Prowling static void Zigzag while s readValue 50 do wayfinder Evasion Hunter det while wayfinder get total lt 80 actuator rotate 135 do wayfinder Evasion Hunter det while wayfinder get total lt 80 actuator rotate 360 do wayfinder Evasion Hunter det while wayfinder get total 80 Daniel Egido S nchez de Vega Section III Source Code ROBOT PATROL SYSTEM 154 actuator rotate 135 actuator travel 30 Hunter det actuator rotate 45 do wayfinder Evasion Hunter det while wayfinder get total lt 60 actuator rotate 360 do wayfinder Evasion Hunter det while wayfinder get_total lt 80 actuator rotate 135 do wayfinder Evasion Hunter det while wayfinder get total 80 actuator rotate 360 do wayfinder Evasion Hunter det while wayfinder get_total lt 80 actuator travel 133 Hunter det
151. ure from both Daniel Egido S nchez de Vega Section I Report ROBOT PATROL SYSTEM extremes of the obstacle by performing the frontal sensor So far it is the beautiful theory but actually this technique cannot works with no extra additions Just in exceptional situations as facing a corner or similar the rays being shot would became returned to the correct receiver position but usually this will not happen as trying to measure the distance to the extreme of the obstacle the rays would go away and finally lost useless F Figure 18 Shortcut calculation Daniel Egido S nchez de Vega 33 Section I Report ROBOT PATROL SYSTEM The idea implemented in the source code is to detect the cornered end of the obstacle by making sensor shots until the signal is not more received that means the obstacle is finished and then some calculations are made to register the resulting distance The conclusion is that is needs to receive the signal from the obstacle bound for working with this technique For that it must do some change There are several options to consider Just one of them is referred to the robot If it used a commercial ultrasonic sensor featured by burst type and wider radial range then it exists more possibilities to obtain the signal if the robot is close enough to the obstacle bound But as it has to manage with Lego robot this is not a feasible possibility so it focuses the attention on the other alter
152. us getDistance 255 angle angle 10 pilot rotate 10 bound us getDistance s_angle int angle s long int s_bound Math sin Math toRadians angle s long s long 25 pilot rotate s angle pilottravel s long if deg 0 pilot rotate 90 if deg lt 0 pilot rotate 90 pilot travel travel long if deg gt O pilot rotate 90 if deg lt 0 pilot rotate 90 pilot stop int get s long double get_angle return s long return angle ERE HEH TEE EHE EHE ERE E EHE ERE EE HE HR RR RR B ET Daniel Egido S nchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 109 import lejos navigation Pilot import lejos nxt LCD import lejos nxt Motor import lejos nxt SensorPort import lejos nxt Sound import lejos nxt UltrasonicSensor public class EvasiveBot static Pilot pilot new Pilot 5 6f 10 5f Motor A Motor C wheel diameter trackwidth leftmotor rightmotor static UltrasonicSensor us new UltrasonicSensor SensorPort S1 static Obstacle obs new Obstacle static Avoid overcome new Avoid static String dist distance static String unit unit public static void main String args int i 0 attempts counter int n 0 avoided obstacles counter int waylength 0 length of the way to travel int total 0 total straight distance traveled boolean clearway do pilot r
153. vate UltrasonicSensor sonic new UltrasonicSensor SensorPort S1 private SonarData sonar public SonarSensor SonarData SD sonar SD public void readSonarData sonar setDistance sonic getDistance THERE A E EEETEETEET EEe package rpss utilities import lejos nxt Sound public class Speaker public void Beep Sound beep TERES d EE A Ha Da De D A D Ee package rpss utilities import lejos navigation Pilot import lejos nxt Motor public class WheelActuator Daniel Egido S nchez de Vega 183 Section II Source Code ROBOT PATROL SYSTEM 184 private Pilot pilot 2 new Pilot 5 6f 11 3f Motor C Motor A false public void Forward pilot forward j public void Stop pilot stop pilot resetT achoCount public void Rotate int angle pilot rotate angle Daniel Egido Sanchez de Vega Section HI Source Code ROBOT PATROL SYSTEM 185 package selab rpss import java io DatalnputStream import java io DataOutputStream import java io IOException import Constants Protocol import rpss utilities RPCoordinator import lejos nxt L CD import lejos nxt comm BT Connection import lejos nxt comm Bluetooth Bluetooth public class RobotPatrolSystemServer private Object syncObj new Object private RobotPatrolSystemServerListener listener null private BTConnection btc private DatalnputStream dis private Da
154. void skidding Ref DAMG07 Daniel Egido S nchez de Vega X w Section I Report ROBOT PATROL SYSTEM 15 A Figure 5 Other casters Ref DAMGO07 Selecting one or several casters depends on the specific work or task for which the robot is being designed For example a single caster is enough for most applications including which are approached in this project but two casters at the front and rear of the robot are a better option when stability is important being a characteristic at risk Another option not so known or common it is to use a plastic ball instead of casters If the robot is moving on a smooth surface a large ball performs like as a caster The advantage of this approach is that it has not caster wheels to get caught up and the ball will turn if it can This approach will not work well if the robot is moving across a surface that has a rubbery texture Daniel Egido Sanchez de Vega EM o v Section I Report ROBOT PATROL SYSTEM Although the ball turns freely within the cup structure it is still subject to friction within it Figure 6 Differential Drive with plastic ball implemented Skid Steer Drive This is a variation of the differential drive Usually it is used with tracked vehicles but sometimes with four or six wheel platforms as well In the case of tracked vehicles this architecture is the only driving option There are in reality quite good examples of skid steer drives

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