Final Report - EE Senior Design
Contents
1. SPIsend 0b11001110 We want to write to register x E CIRQ_MASK SPIsend Qb00001000 Setting bit 3 enable IRQ_3 CTRX_END at_sel 1 return void disable_irg_3 void at_sel Q SPIsend b11001110 SPIsend Qb00000000 at_sel 1 return void select_channel char channel f at_sel SPIsend b11001000 SPIsend channel at_sel 1 return void transmit char data char size char seq char channel select_channel channel set_trx_state 8 90x08 33 set_trx_state 9 9x09 write_frame data size seq set_trx_state 2 7 0x02 return void receive char channel select_channel channel set_trx_state 8 0x8 33 set_trx_state 6 0x06 return Wireless SPI pins SEL B4 out MOSI C5 out MISO C4 in SCLK C3 out IRQ BO in SLP_TR A3 out RST B5 out PWM pins PWM1 C2 out CECCP1 Reset1 D out PWML1 D1 out SR1 D2 out Phasel D3 out FF11 B1 in FF21 B2 in PWM2 C1 out CCP2 Reset2 D4 out PWML2 DS out SR2 D6 out Phase2 D7 out FF12 B3 in FF22 B6 in Metal Detector Pins M1 E0 in MD2 El in MD3 E2 in Solenoid Pin Sol A7 out Level Shifter output enable OE A2 out void main void char received We want to write to register x E CIRQ_MASK clear bit 3 disable IRQ_3 TRX_END Co2. else ifCadif 1 adif char SPIsend char sent_byte char returned_byte sspif sspbuf sent_byte while sspif 0 returned_byte sspbuf sspif return returned_byte char read_register char reg char tosend 0b10000000 char ans at_sel Q tosend tosend reg SPIsend tosend Interrupt flag set low Load buff with data to send Wait for interuput indicating send complete After interrupt buffer contained returned data Clear interupt flag again for good measure Function returns recieved information Start off with the read command OR the read command with the register we want to read ans SPIsend Q b0Q000000 Send gibberish to read the data in the register at_sel 1 return ans char write_frame char data char size char seq char received at_sel Q SPIsend Qb0110000Q Frame write access command byte SPIsend size 13 PHY header PHR with MSB reserved frame Length SPIsend 0b00000000 Reserved 7 IntraPAN 6 ACK Request 5 Frame Pending 4 Security enabled 3 Type 2 0 SPIsend b1000100Q Source addressing mode 15 14 Frame version 13 12 Destination addressing mode 11 10 Reserved 9 8 SPIsend seq Sequence number Addressing fields go here if we the set the SAM and the DAM accordingly SPIsend 0b10101010 Destination PAN ID QxAAAA Robot SPIsend 0b10101010 SPIsend b1011101
3. the TMR2 prescalar value of 4 volatile bit tmr2on T2CON 2 1 Enable Timer2 Start the PWM output Note that each bit of the configuration registers is declared separately to facilitate changes that may need to be made to them in the main program flow The duty cycle of the PWM is essentially what determines the speed of the motor A 100 duty cycle corresponds to full power to the motors 50 is half power and 0 is no power Our design utilizes an 8 bit duty cycle register providing us with 256 different values for the duty cycle of the PWM signals The duty cycle information is generated by the software internally after receiving input from the joysticks over the wireless connection The joystick values described in more detail in the remote subsystem section range from 0 to 255 with 127 being neutral The values of the joystick input are mapped to the corresponding duty cycle and phase direction by the following code 51 if received 11 gt 132 J1 is forward latd 3 1 Phasel is 1 forward ecpril 2 received 11 132 Map the forward range of the joystick to the full range of duty cycle else if received 11 gt 120 amp amp received 11 lt 132 J1l is in neutral cecprll 0 Duty cyclel is 0 else if received 11 lt 120 J1 is in reverse latd 3 0 Phasel is 0 reverse ecpril 2 121 received 11 Map the reverse range of the joystick to the full range of duty cylc
4. 1 enable_irg_3Q receive CHAN Put the Atmel chip in a state to receive data whileC readytoread Wait here for a response from the remote received read_frame Read the data from the remote readytoread delay_ms 100 Update our PWM signals with the joystick information from the remote 31 ifCreceived 11 gt 132 J1 is forward latd 3 1 Phasel is 1 forward ccpril 2 Creceived 11 132 Map else if Creceived 11 gt 120 amp amp Creceived 11 ccpril 0 else if received 11 lt 120 latd 3 Q ccpril 2 121 received 11 Map J2 ifCreceived 12 gt 132 latd 7 1 ccpr2l 2 Creceived 12 132 Map else if received 12 gt 120 amp amp Creceived 12 ccpr2l else if received 12 lt 120 latd 7 ccpr2l 2 121 received 12 Map the forward range of the joystick to the lt 132 J1 is in neutral Duty cyclel is J1 is Phasel is reverse the reverse range of the joystick to the Phase2 is 1 forward the forward range of the joystick to the lt 132 J2 is in neutral Duty cycle2 is J2 is Phase2 is reverse the reverse range of the joystick to the Update the solenoid MOSFET gate signal with the button information from the remote lata 7 received 13 Rinse and repeat End main Sol button full range of duty cyclei in reverse full range of
5. Design Changes ess cccsxcsssecssacisanspusesesnvassontstosebsenedasesetenubsoessccsstotuavbuatedeeessnaineacenies 22 GC OTEMISIO IS as dbcctbevaaeesasesedesestedesseeesLussestnaaccatvecdstectacteatee Gucisibeencstecte 22 Vi PPP CMI CLOS oi costsscicacGantdeatoccccceusivcduccontuooastauedeeneacowous cesavonconssnsssenedenchoaussnsonueiavcastosenetouatmecssssenacs 23 1 Introduction According to the UNICEF almost 10 000 people per year are killed by land mines most of whom are civilians Thousands more people lose limbs livelihoods or loved ones1 In many cases the conflict is long over but the danger remains due to the difficulty of finding and destroying the mines Yet destroying them is imperative for long term safety and with over one hundred million planted world wide it is a daunting task Substantial action is required but one must disarm a hundred million deathtraps 1 1 Problem Description The problem is the minefield itself a large area where a large number of explosive devices are randomly hidden They cannot be spotted visually since many are buried or designed to be difficult to detect Disarming them personally would be extraordinarily hazardous especially without knowing where the mines are buried Our solution is a wirelessly controlled robot capable of locating the mines and marking them for future removal The main goal is to keep humans out of danger and by remotely locating the mines disposing of them becomes much
6. Shifter output enable lata 2 1 0E high stays this way A D converter config register adcon1 QxOF Reset Atmel part before setting SPI registers at_rst Q delay_ms 5 at_rst 1 SPI config registers volatile bit smp SSPSTAT 7 0 Input data sampled at end of data output time volatile bit cke SSPSTAT 6 1 SPI clock selecte bit Transmit occurs on transition from Idle to active clock state volatile bit sspen SSPCON1 volatile bit ckp SSPCON1 4 volatile bit sspm3 SSPCON1 volatile bit sspm2 SSPCON1 volatile bit sspm1 SSPCON1 Q Serial Synchronous Enable bit Clock Polarity Select bit Idle state for clock is low level SSPM lt 3 0 gt Synchronous Serial Port Mode Select bits 0000 SPI Master mode clock FOSC 64 io OrPnNwi un i eros volatile bit sspm SSPCON1 0 PWM Period pr2 OxFF Set PWM port directions volatile bit trisc2 TRISC 2 Q PWM1 C2 out CECCP1 volatile bit trisd TRISD Reset1 D out volatile bit trisd1 TRISD 1 PWML1 D1 out volatile bit trisd2 TRISD 2 SR1 D2 out volatile bit trisd3 TRISD 3 Phasel D3 out volatile bit trisb1 TRISB 1 1 FFil B1 in volatile bit trisb2 TRISB 2 1 FF21 B2 in volatile bit trisc1 TRISC 1 PWM2 C1 out CCCP2 volatile bit trisd4 TRISD 4 Q Reset2 D4 out volatile bit trisd5 TRISD 5 Q PWML2 D5 o
7. easier Even if a mine is triggered during the marking process the loss of a robot is a small price to pay in comparison to that of a human life However it was still important to design a robot that would not detonate any mines that were discovered In order to further enhance safety it was also imperative that the mines be accurately marked and users could operate the robot from a safe distance 1 2 High Level Description The Mine Detecting Robot system consists of two main parts the robot itself and the remote control system used to drive the robot and display information to the user The two parts communicate with each other through a wireless connection that sends control information to the robot and returns sensor information to display on the remote The core of the robot system is a microcontroller that receives input from the metal detecting sensors as well as from the wireless transceiver The wireless information is processed and sent to the motor driver circuits and the marking system while any information from the metal detectors is sent back to the remote through the wireless transceiver The core of the remote control system is also a microcontroller which receives inputs from joysticks mounted on the remote control board Joysticks function as analog potentiometers and when these signals are sent through analog to digital converters a digital signal that can be sent to the robot is obtained In order to communicate with th
8. needed to be configured to allow data to be sent between the two chips The 18f4321 can be configured to output SPI compliant data SPI consists of 4 basic signals Master Out Slave In MOSI Master In Slave Out MISO a clock signal and a select signal In addition to the four main SPI signals the communication channel to the transceiver chip also utilizes a sleep trigger signal a reset signal and an interrupt signal Once this setup was done data could be successfully sent between the parts allowing for the basic underlying structure that made the wireless communication successful 3 System Integration Testing Through our design process testing of our designs led to a variety of alterations and improvements upon our initial plan to try to satisfy our system requirements The following is an overview of the testing process and the adaptations of our design during the development of our robot 3 1 Mechanical Integrated Testing The system requirements of our robot that were of greatest concern to the mechanical systems in our robot were the ability of the robot to traverse a field the ability to detect mines within the sweep of the robot and the ability to mark those mines with our marking system In order to test these requirements and ensure that we were able to fulfill them we needed to test each of the following components of the robot the treads the motor the mounting setup for the marking system the frame layout and the design of
9. out LED3 D3 out void main void char received char to_send 3 unsigned long hangcounter char sequence Q Oscillator config registers volatile bit ircf2 0SCCON 6 1 volatile bit ircf1 0SCCON 5 volatile bit ircf OSCCON 4 volatile bit scs1 0SCCON 1 1 tol PR Wirless SPI port directions volatile bit trisc5 TRISC 5 Q volatile bit trisc4 TRISC volatile bit trisc3 TRISC volatile bit trisb4 TRISB volatile bit trisbQ TRISB volatile bit trisa3 TRISA volatile bit trisb5 TRISB vworw l Seredcdr Joystick port directions volatile bit trisa TRISA volatile bit trisal TRISA 1 1 Il m Button port direction volatile bit trisd TRISD 1 LED port directions volatile bit trisd1 TRISD 1 Q volatile bit trisd2 TRISD 2 Q volatile bit trisd3 TRISD 3 Init the LED signals to zero latd 1 latd 2 latd 3 Interrupt config registers volatile bit peie INTCON 6 1 volatile bit int ie INTCON 4 1 MD converter config register adcon1 QxQd The next 3 bits set the internal oscillator frequency to 8 Mhz Use the internal oscillator block as the system clock MOSI out MISO in SCLK out SEL out IRQ in SLP_TR out RST out J1 in J2 in Button in LED1 out LED2 out LED3 out LED1 off LED2 off LED3
10. output to actually be generated the TIMER2 module must also be configured properly as it provides the timing for the outputed signals Once timer2 is configured and activated PWM output starts Below is the CCPxCON and TIMER2 configuration code PWM Period pr2 OxFF Set the period of the PWM frequency as related to timer2 PWM1 ECCP1 config registers volatile bit plm1 CCP1CON 7 0 Single Output PlA volatile bit plm0 CCP1CON 6 0 volatile bit dclb1 CCP1CON 5 0 Bitl of duty cyclel always 0 for 8bit resolution volatile bit dc1bO CCPICON A 0 BitO of duty cyclel always 0 for 8bit resolution volatile bit ccplm3 CCP1CON 3 1 The next 4 bits correspond to setting volatile bit ccplm2 CCP1CON 2 1 all PWM outputs ECCP1 to be active high volatile bit ccplm1l CCP1CON 1 0 volatile bit ccplm0 CCP1CON 0 0 HER PWM2 CCP2 config registers volatile bit dc2b1 CCP2CON 5 0 Bitl of duty cycle2 always 0 for 8bit resolution volatile bit dc2b0 CCP2CON 4 0 BitO of duty cycle2 always 0 for 8bit resolution volatile bit ccp2m3 CCP2CON 3 1 The next 4 bits correspond to setting volatile bit ccp2m2 CCP2CON 2 1 CCP2 into PWM mode volatile bit ccp2m1 CCP2CON 1 0 LER volatile bit ccp2m0 CCP2CON 0 0 RIFF Timer2 config registers for PWM volatile bit t2ckps1 T2CON 1 0 The next two bits correspond to volatile bit t2ckps0 T2CON O 1
11. the joystick enclosure 17 In order to test the treads they were first mounted to the frame and connected to the motors They were then tested by driving the robot around on a smooth surface and then on grassy surface outside to mimic the terrain of a mine field When we first drove the treads with the load of the robot we noticed several issues that needed to be monitored for our setup to work properly First we found that the tension on the treads must be set properly in order for the robot to be able to drive at all Setting the tension too high puts stress on the gearbox and prevents the treads from turning at all while setting the tension to low causes the treads to bend around the wheel connected to the gear box This bending causes adjacent treads to hit each and either results in a loud clicking noise while the robot is moving or a lock up in the treads which prevents the robot from moving at all Setting the tension correctly simply required inserting the proper number of links The testing of the motor system was done initially in early a December and again once the motors we chose for our final design arrived in the spring Initially we tested the proper function of the H bridge circuitry and the allegro chip we selected in December using motors similar to the those we would use in our final design which were provided to us in the storage room These motors we run without a comparable load to the that of the final robot however they demo
12. 0000 Read in the one byte message store i read Store the received byte at_sel 1 13 read register 15 Reading register 15 signals to the Atmel chip that the read has finished return store The next function is used to consolidate the steps required for wireless data transmission into one easy to use easy to read function void transmit char data char size char seq char channel select _channel channel set_trx_state 8 0x08 TX_OFF set_trx_state 9 0x09 PLL_ON transmission on write frame data size seq set_trx_state 2 0x02 TX_START start transmission return The receive function is similar to the transmit function except that it puts the chip into a state to receive The software must then wait for the interrupt signal on IRQ signaling that the buffer is full and ready to read and then the frame buffer can be read and the packet information extracted void receive char channel select channel channel set trx state 8 0x08 TX_OFF set_trx_state 6 0x06 RX_ON enter state RX_ON and continuously check for frames return For the complete robot and remote transmission system the robot and remote takes turns sending data packets out to the other and waiting for a return packet This is accomplished using the code below disable irq 3 transmit to_send 3 sequence CHAN sequence sequence 1 delay ms 1 enable irq 3
13. 1 Destination address QxBBBB Robot SPIsend b10111011 SPIsend 0b11001100 Source PAN ID xCCCC Remote SPIsend 0b11001100 SPIsend b11011101 Source address xDDDD Remote SPIsend b11011101 for int i 0 i lt size i received SPIsend data i Data payload SPIsend 0b00000000 Frame check sequence FCS 2 bytes SPIsend 0b00000000 at_sel 1 return received char read_frame void access buffer char read char store 128 char frame_length at_sel Q SPIsend 0b00100000 Command byte for Frame buffer read frame_length SPIsend 0b00000000 Read in PHR byte stating how many bytes are in the LCD_bin frame_length for int i i lt Cframe_length 1 i f Iterate through frame_length 1 last byte is lqi if i gt 127 i 127 read SPIsend Qb00000000 Read in the one byte message store i read Store the received byte at_sel 1 read_register 15 return store char check_trx_status void char ans at_sel SPIsend 0b10000001 We want to read register x 1 CTRX_STATUS ans SPIsend Q b0Q000000 Send gibberish and return the value of the register at_sel 1 void set_trx_state char cmd return ans at_sel SPIsend b11000010 SPIsend cmd at_sel 1 return void enable_irq_3 void at_sel SPIsend 0b11001110 SPIsend 0b90001000 at_sel 1 return
14. 1001100 SPIsend 0b11011101 Destination address xDDDD Remote SPIsend b11011101 SPIsend Qb10101010 Source PAN ID xAAAA Robot SPIsend Q b10101010 SPIsend b10111011 Source address xBBBB Robot SPIsend b10111011 for int i 0 i lt size i received SPIsend data i Data payload 3 SPIsend Qb00000000 Frame check sequence FCS 2 bytes SPIsend Qb00000000 at_sel 1 return received char read_frame void char read char store 128 char frame_length at_sel SPIsend Qb00100000 Command byte for Frame buffer read access frame_length SPIsend Qb00000000 Read in PHR byte stating how many bytes are in the buffer LCD_bin frame_length for int i 0 i lt frame_length 1 i Iterate through frame_length 1 last byte is lqi if i gt 127 i 127 read SPIsend Q b00000000 Read in the one byte message store i read Store the received byte at_sel 1 read_register 15 return store char check_trx_status void char ans at_sel SPIsend 0b10000001 We want to read register x 1 TRX_STATUS ans SPIsend 0b00000000 Send gibberish and return the value of the register at_sel 1 return ans void set_trx_state char cmd at_sel Q SPIsend 0b11000010 We want to write to register 0x02 TRX_STATE SPIsend cmd at_sel 1 return void enable_irg_3 void at_sel
15. CON2 2 adcs1 ADCON2 1 adcs ADCON2 POOF adon ADCON 1 go ADCONO 1 1 1 to_send Q adresh joystick value delay_us 20 aquisition on J2 chs3 chs2 chs1 chs adon go process PHRro0oo while go 1 done to_send 1 adresh joystick value delay_us 20 Get the state of the button to_send 2 button the button input Begin wireless dance disable_irqa_30 transmit to_send 3 sequence CHAN sequence sequence 1 delay_ms 1 enable_irg_3Q receive CHAN data whileC readytoread retransmit hangcounter hangcounter 1 ifChangcounter gt 100000 failedtoconnect 1 readytoread 1 Select channel J1 adresh will contain the 8 MSBs of the result The next 3 bits set the A D aquistion time to 20 Tad Longest possible aquisition time because I The next 3 bits set the A D conversion clock to Tosc 8 LE Turn on the A D converter module Start the aquistion conversion process Wait here until the A D coversion is Load up the to_send array with the first Wait some time before starting the next Select channel 1 J2 Turn on the A D converter module Start the aquistion conversion Wait here until the A D coversion is Load up the to_send array with the second Wait again just in case Load the 3 byte of the array with the value of Transmit t
16. LN VN LZ NN WNL ON NERENNENENLZZENEN NENNEN Nee RN NEN WSN AN ANANIN AIN AN V__ VIV_LS INE NAS a CONFIG4L _LVP_OFF_4L amp _XINST_OFF_4L Atmel Chip select Atmel Chip reset Atmel Chip sleep set high to make not sleep MD1 volatile bit MD2 volatile bit MD3 volatile bit SPI interupt flag indicates SPI send complete INT interupt flag from port b that is connected to IRQ on the Atmel Interrupt flag set low Load buff with data to send MNait for interuput indicating send complete After interrupt buffer contained returned data Clear interupt flag again for good measure Function returns recieved information Start off with the read command OR the read command with the register we want to read Send gibberish to read the data in the register char write_frame char data char size char seq char received at_sel Q SPIsend Qb01100000 Frame write access command byte SPIsend size 13 PHY header PHR with MSB reserved frame length SPIsend Qb00000000 Reserved 7 IntraPAN 6 ACK Request 5 Frame Pending 4 Security enabled 3 Type 2 0 SPIsend 0b10001000 Source addressing mode 15 14 Frame version 13 12 Destination addressing mode 11 10 Reserved 9 8 SPIsend seq Sequence number Addressing fields go here if we the set the SAM and the DAM accordingly SPIsend 0b11001100 Destination PAN ID xCCCC Remote SPIsend b1
17. Robot Rangers Final Report Ben Andersen Jennifer Berry Graham Boechler Andrew Setter 5 6 2011 EE41430 Table of Contents DOU HOM sessncc sachets ccc snes cosbetsis cdabessaasebdacesdesunsadesieisiuc shadsanseddceeddescusceusiecdecesepvasesebucuddaaudesieseeay 3 1 1 Problemy DOS Crip tise ss sasessssssouhssooudssassvenvonedasdusssaeseboaubesvenssvousbecunncacentseaviacenneasiesseaens 3 1 2 High Level Description sesssecssooessoessossssesssoessooesoossssssssesssocssoossoosssossssesssoessoossossssse 3 LS Systemi REQUiIr eM CNt8 scsecsccsissscedussevedsddunstvcseseeseadsnnscuccseuesdensasceud esungessbavscecacsscedescedsese 4 1 4 Subsystem Requirements cssscsscsaciicccsssccsnsionissvcdsaessvedensunsdvencssvckosteeecssaconsedeataveddsaroonsce 4 1 5 Future Enhancement RequirementsS uersssssssssnsssssnsssssnsssnsnnssnsnnsnnnnnsnnnnnsnnnnnsnnnnnennene 6 1 6 Design Resulfs unse eisen 6 2 Detailed Project Description issccsssusaczsssensnsseongsscskosspuscsscessdssouapnestosssedesrospasssontosdessinpucsveutveceuens 6 2 1 System Theory of Operation sscccesscevssvecsisccevoveseanssewiadenesetoonscsdeacesesavasseveseeravsscusssoenvasees 6 2 2 System Block Dia Sra secscccscsedsecscicsvesesesssoendecseoscsodedsecnensesensodecsssboudoscersiadonenstursecsnvecsens 7 2 3 Detailed Operation of Marking System sesssssssssnsssssnsssnsnnsnnsnnsnnnnnsnnnnnsnnnnnennnnnenne 8 2 4 Detailed Operation of Detection System suussssosssssnss
18. Tose 8 volatile bit adcsO ADCON2 0 1 volatile bit adon ADCONO O 1 Turn on the A D converter module volatile bit go ADCONO 1 1 Start the aquistion conversion process while go 1 Wait here until the A D coversion is done to_send 0 adresh Load up the to_send array with the first joystick value delay_us 20 Wait some time before starting the next aquisition on J2 chs3 0 Select channel 1 J2 chs2 0 chsl 0 chs0 1 adon 1 Turn on the A D converter module go 1 Start the aquistion conversion process while go 1 Wait here until the A D coversion is done to_send 1 adresh Load up the to_send array with the second joystick value delay_us 20 Now that the sensor information has been gathered the data is wirelessly transmitted to the robot see the wireless subsystem description section and the information from the robot is received The received information is then directly extracted and used to illuminate the LEDs on the control board This is accomplished by setting the LED pins to digital outputs and setting their value high The output pin is then wired through the LED and a current limiting resistor and connected to ground This code is on an infinite loop and will continue to update the information until either the robot or the remote is turned off 2 8 Detailed operation of main robot system The main robot system is similar to the remote control system such tha
19. ate fast enough to ensure no more than 1 second of lag to the robot Wireless connection must have a range of least 50 meters 1 4 3 MINE DETECTION SYSTEM Must detect mines within 6 of each side of the robot Spray paint mark must be at least partially over mine Must be able to mark a large number of mines Must not set off mines during scanning and marking process 1 4 4 MICROCONTROLLER Must have a separate input for each metal detector Must have enough additional inputs to accommodate the number of sensors needed for autonomous movement to allow for future enhancement Must have RS232 capabilites Must be able to generate a PWM signal Must have SPI functionality to communicate with ATMEL RF231 chip Must have analog to digital conversion functionality 1 4 5 ROBOT POWER MANAGEMENT Must be capable of supplying power to robot for at least 30 minutes when in normal operation Must be able to supply power for at least two hours when robot is in standby mode 1 4 6 MOVEMENT SYSTEM Must be able to move in response to user input Must be able to turn in place Must be able to vary speeds of both treads Must be able to move in forward and full reverse Must be able to move on hard surfaces grass gravel dirt and slightly wet ground 1 5 Future Enhancement Requirements The robot would be even more effective if it did not require constant supervision and instruction from an operator which would be accomplished through the addition o
20. bot must preform three essential tasks move remotely detect mines and mark them Firstly for movement the robot requires a board that takes user input through joysticks a method of sending the information to the robot and receive information from the robot and a board capable of receiving information from the remote and sending back information Therefore two antennas are needed and a method of encoding information so it can be sent between them Finally the board must be able to control multiple motors to execute the instructions from the remote The detection system must accurately locate landmines The detectors will generate a magnetic field and monitor changes in it to observe the location of metal Then the detector must send a signal to the main microcontroller to indicate the presence of metal To send information to the user the presence of metal must encoded into bits to be send over the wireless connection and displayed on the remote control through an indicator The marking system must display a permanent and highly visible mark on the ground indicating the location of a mine This must not be a destructive of forceful action as that would risk detonating the mine Furthermore it must be activated by the remote control so a signal to fire must be sent over the wireless connection and be processed by the main robot board 2 2 System Block diagram Marking System GE eS Cu ee S Metal Robot Wireless Remote Detectors Micr
21. ctor and marks the desired location To test the mechanical operation of the marking system the solenoid was connected directly to a 12 volt power supply It showed it had the necessary force to activate the spray paint can 2 4 Detailed operation of Detection System Each of the metal detectors is powered from a nine volt power supply on the microcontroller board The metal detectors contain a coil of wire which sends out a local magnetic field The current in the coil responds to changes in the field due to the presence of metal and the detector then sends a high signal through a buffer to the microcontroller itself to indicate the detection Next the microcontroller sends a signal through the wireless connection to the remote control which lights the appropriate LED To test the system a metallic watch was moved in and out of each detector The LED on the remote control was observed and the correct one illuminated 2 5 Detailed operation of motor control system The robot s propulsion system consists of two motors mounted to two tread systems on either side of the robot The power to the motors is controlled via pulse width modulation PWM which is generated by two separate motor control circuit boards one for each motor On the circuit board is a full H bridge MOSFET configuration which is controlled via the Allegro A3941 bridge driver IC The motor control circuit boards receive their control information from the main robot circu
22. demonstrated to meet requirements through the operation of the treads If the threads can be moved with varying speed and direction the motor system is fully functional If the robot can preform these while in outdoor terrain then the motor selection was accurate and the robot meets all movement requirements By operating the robot from a reasonable distance by the remote the entire software system is shown to be functional To move the robot the input must be received through the joysticks encoded and sent to the robot and decoded and implemented by the motors So long as lag is not observed the system is satisfactory The detection system can be directly tested by placing metal in range of the detectors and observing if the appropriate indicator lights up The metal can be moved to determine the range of the detectors and they were calibrated to meet requirements The detection system did not meet requirements but operated when connected to an external supply Although it could not be operated on the robot it passed the mechanical requirements it just could not operated through the main board Through our demo the robot stayed in standby mode for approximately four hours with a negligible drop in battery voltage exceeding power management requirements even with intermittent activity Furthermore it functioned through all tests while not directly tested it meets the thirty minute activity requirements 4 Users Manual 4 1 How to ins
23. duty cylcel J2 is forward full range of duty cycle2 in reverse full range of duty cylce2 FIR Az A PX SEN ZEN ALN wo NNN EN EN ON AALY AN en ea im dem a ead NR EN NEON ZELLEN EN NEN DE ERDE TN Pr N Fra NN FEN GEN VN WN ZX ALN NN ALN AWW ALN NN NL VN WN ZX ALVA WN VN ALN WX ZN WX N NNN AN Nt J NON Pe NOREEN NINAN NEA NEN NENNEN Ne NN cae NO NEN ZN EZ NDS ANS NI VE MS PDL INA LAS ANS ANLAN ANN IN i DI A SS eras NDE Team Robot Rangers 7 Version 1 2 Remote 5 2 11 7 include lt system h gt define CHAN 11 pragma DATA _CONFIG1H _OSC_INTIO2_1H pragma DATA _CONFIG2H _WDT_OFF_2H pragma DATA _CONFIG4L _LVP_OFF_4L amp _XINST_OFF_4L pragma DATA _CONFIG3H _MCLRE_ON_3H pragma CLOCK_FREQ 8000000 Global variables volatile bit at_sel PORTB 4 Atmel Chip select volatile bit at_rst PORTB 5 Atmel Chip reset volatile bit at_s1p PORTA 3 Atmel Chip sleep set high to make not sleep volatile bit button PORTD Button volatile bit volatile bit sspif PIR1 3 SPI interrupt flag indicates SPI send complete volatile bit int if INTCON 1 INTO interrupt flag from port b that is connected to IRQ on the Atmel volatile bit adif PIR1 6 MD converter interrupt flag indicates a conversion is complete bool readytoread Q bool failedtoconnect void interrupt void volatile bit bf SSPSTAT iflsspif 1 sspif else ifCint if 1 intOif 0 readytoread 1
24. e J2 if received 12 gt 132 J2 is forward latd 7 1 Phase2 is 1 forward ccpr21 2 received 12 132 Map the forward range of the joystick to the full range of duty cycle2 else if received 12 gt 120 amp amp received 12 lt 132 J2 is in neutral ccpr2l 0 Duty cycle2 is 0 else if received 12 lt 120 J2 is in reverse latd 7 0 Phase2 is 0 reverse ecpr21l 2 121 received 12 Map the reverse range of the joystick to the full range of duty cylce2 Note received 12 and recieved 11 are the bytes of the incoming wireless packet that contain the joystick information Pins D3 and D7 are the phase direction ports for motor 1 and motor 2 respectively Below is the schematic of the motor control circuit boards featuring the Allegro A3941 bridge driver IC interfaced through the 8 signal PWM cable described above The IC fully controls an H bridge configuration of power MOSFETs used to control power to the motors 10 AZITI J i EF fi I 2 6 Detailed operation of wireless communication system The main robot and remote boards communicate with each other via a wireless connection using the IEEE 802 15 4 protocol This is achieved mainly through the implementa
25. e robot the remote control microcontroller also has a wireless transceiver It sends control information such as joystick position and button depression to the robot and displays information about the metal detector array in an LED configuration on the remote controller board 1 3 System requirements OVERALL SYSTEM Must maintain a wireless connection out to 50 meters Must have a battery life of at least 30 minutes when in normal operation Must have a battery life of at least 2 hours when in standby mode Must detect and mark mines Must not cause mines to detonate 1 4 Subsystem requirements 1 4 1 REMOTE CONTROL SYSTEM Must run on battery power Must control movement of robot through two joysticks Movement of the robot must be able to be controlled through a physical user input interface Physical user interface must accept inputs based on user input and send outputs to the robot Physical user interface must send output i e commands to the robot via a wireless connection Must have LED configuration to show output of metal detectors to the user Physical user interface must be easily understood and operated without significant training 1 4 1 REMOTE CONTROL SYSTEM Must be powered by either a battery or a power brick connection Battery life of the unit must last at least 2 hours Physical user interface must send commands to the robot via a wireless connection teal WA IURISIGIS SS WINS AUB REAGE Must be able to communic
26. etal detector The corresponding LED on the remote control should blink on and off To test the marking system press and release the mark button on the remote If the lever pushes the can and it sprays paint onto the ground the system is functional 4 4 How the user can troubleshoot the product If the robot is not moving correctly First try resetting the motor boards using the button on the remote control If this does not solve the problem manually reset the remote control and the board inside the robot If the robot still does not move check both treads and ensure they are moving freely and attached properly If none of these resolve the problem try charging or replacing the remote and main batteries If the metal detection system does not activate ensure no wires have come loose within the robot If there is no break in the wiring and the main and remote batteries are functional then the faulty metal detector needs to be replaced If a metal detector fires continuously even when no metal is resent reduce the sensitivity of the detector using a small screwdriver by turning the threshold dial on the side of the detector It appears as a screw inside a hole along the side of the detector Do not loosen the screws on the bottom of the detectors this will cause them to fall apart If the marking system does not function ensure the can has not depleted after repeated use replace it if necessary If this does not solve the problem en
27. f an autonomous mode This would be difficult since the microcontroller would have to be able to independently sense it s environment and position itself over a detected mine in order to mark it Another future addition would be a digital copy of the locations of the mines creating a map for future reference This would require significant programming to accurately track the relative location of the robot and the location of the mines 1 6 Design Results The design while meeting most of our expectations did not meet all of them The electronics and wireless system which posed the majority of the challenges we needed to overcome were implemented successfully The motor system functioned the majority of the time the robot was mobile and met design requirements However we were unable to determine why the hardware would stop working when if the robot accelerated too fast The other disappointment was the marking system While the mechanical aspects were functional it could not be operated from our main board We believe though are not certain that the battery pack could not supply sufficient current Although we did not meet all of our requirements the problems were relatively minor especially considering the complexity of our system and what we needed to do to complete what we did 2 Detailed project description 2 1 System theory of operation The main goal of the robot is to remotely locate and mark landmines To accomplish this the ro
28. he remote info on the value of CHAN Put the Atmel chip in a state to receive If you ve waited to long break out and from the robot Wait here for a response hangcounter received read_frame Read the data from the robot readytoread ifCfailedtoconnect If there was no connection set the received information to zero received 11 Q received 12 Q received 13 Q failedtoconnect J delay_ms 100 Light the LEDs with the received information from the robot latd 1 received 11 LED1 MD1 latd 2 received 12 LED2 MD2 latd 3 received 13 LED3 MD3 Rinse and repeat End main Relevant parts or component data sheets Solenoid MOSFET http www fairchildsemi com ds FD 2FFDD3N40 pdf ATMEL Chip http www atmel com dyn resources prod_documents doc5131 pdf Microcontroller http ww1 microchip com downloads en DeviceDoc 39689f pdf Solenoid http www quardian electric com pdf 11DCFrameSolenoids pdf Level Shifter http search digikey com scripts DkSearch dksus dll Detail amp name 296 21527 1 ND Quad Op Amps http search digikey com scripts DkSearch dksus dll Detail amp name LT16391IS 23PBF ND Adjustable 9V level shifter http search digikey com scripts DkSearch dksus dll Detail amp name 497 1239 1 ND FT232RL http search digikey com scripts DkSearch dksus dll Detail amp name 768 1007 1 ND 38
29. ign and upgrading several of the robotic components Among these necessary 22 improvements the glitch that causes the robot board to hang when power to the motors is either rapidly applied or applied for a long duration of time must be fixed The tread system must also be upgraded by either installing larger more durable treads with larger ground clearance or an all terrain wheel system The marking system in a commercial system must be upgraded to provide a functioning clearly identifiable marking of detected mines Additionally the use of more high end metal detectors would allow for a more extensive and selective detecting of landmines Overall however we were able to demonstrate the functioning of a prototype system which shows a potential solution for addressing a serious issue whihc effects people in countries the world over 7 Appendices i 2 lt cr BRIDGE DRIVER 3941 Th i a EE i EF C mile res au Aa BE e Ip l Tall l by Motor Controller Board Schematic eeeeee eesg 2 OQA O19 DID 2 Motor Controller Board Layout 23 ONOG NGING GI Robot C
30. ing the position of both the buttons and the potentiometers on the remote board and the metal detector signals from the robot Additionally these features needed to function out to the 50m range specified in our system requirements In order to test the information being sent by the wireless system we connected both the packet sender and packet sniffer boards provided to us by Professor Schafer The sniffer board allowed us to read the data being sent by our system and the sender board allowed us to send a known set of data with code we knew was using the proper 802 15 4 protocol Our initial 19 editions of the wireless software showed that when reading data we were not handling the interrupts generated by the ATMEL chip properly Our code was modified so that our boards began to read the frames once the interrupt was generated that signaled that the entire frame had been sent During testing of the wireless we also noticed an issue whereby the remote and robot boards periodically would hang and stop transmitting data to the other boards This issue was addressed by adding in while loops into the code so that the remote board continually transmits data 10 times per second while the robot board waits for the reception of the remote board data before sending the metal detector signals Testing for the wireless range was also conducted by distancing the boards and confirming functionality 3 3 Overall Requirement Satisfaction The movement system is
31. it board via an 8 signal cable The 8 signals that are connected to the main robot circuit board are 1 The main PWM control signal 2 A reset signal to the bridge driver IC It is held high to keep the bridge driver active 3 A PWM low signal It is held low to enable the bridge driver to use the main PWM signal as the control input 4 Asynchronous rectification signal It is held high to allow current to circulate back through the bridge MOSFETs when the motors are coasting 5 A phase signal This signal controls which direction the motors are to rotate and is modulated via software depending on the joystick input from the remote 6 and 7 Two fault signals generated by the bridge driver IC These signals are used by the microcontroller to determine what kind of fault happened if one does occur 8 A ground signal for referencing all of the above voltages The PIC18f4321 microcontroller can be configured to generate PWM output signals The 4321 has two different PWM modules that are used to generate two unique signals for each motor The configuration registers for generating PWM outputs are CCP1CON and CCP2CON The two configuration registers determine which pin it to output the PWM signal whether or not the signal is active high or active low and finally the two LSBs of the duty cycle register Since we are only using 8 bits of duty cycle resolution these two LSBs are configured to zero CCP2CON is configured similarly In order for PWM
32. mmand byte for Register Write Access Channel select byte TX_OFF we have to go to this state first after a power on pg PLL_ON transmission on TX_START TX_OFF we have to go to this state first after a power on pg RX_ON enter state RX_ON and continuously check for frames char to_send 3 char sequence Q Oscillator config registers volatile bit ircf2 0SCCON 6 1 The next 3 bits set the internal oscillator frequency to 8 Mhz volatile bit ircf1 OSCCON 5 1 volatile bit ircf OSCCON 4 1 Vi hae volatile bit scs1 0SCCON 1 1 Use the internal oscillator block as the system clock Wirless SPI port directions volatile bit trisc5 TRISC 5 Q MOST out volatile bit trisc4 TRISC 4 1 MISO in volatile bit trisc3 TRISC 3 Q SCLK out volatile bit trisb4 TRISB 4 SEL out volatile bit trisb TRISB 1 IRQ in volatile bit trisa3 TRISA 3 SLP_TR out volatile bit trisb5 TRISB 5 Q RST out Metal Detector port directions volatile bit trise TRISE 1 MD1 in volatile bit trise1 TRISE 1 1 MD2 in volatile bit trise2 TRISE 2 1 MD3 in Solenoid MOSFET gate port direction volatile bit trisa7 TRISA 7 Sol out Level Shifter output enable port direction volatile bit trisa2 TRISA 2 0E out Init the solenoid MOSFET gate signal to zero lata 7 Solenoid MOSFET off Init the Level
33. ng 4 Security enabled 3 Type 2 0 SPIsend 0b10001000 Source addressing mode 15 14 Frame version 13 12 Destination addressing mode 11 10 Reserved 9 8 SPIsend seq Sequence number SPIsend 0b11001100 Destination PAN ID 0xCCCC Remote SPIsend 0b11001100 SPIsend 0b11011101 Destination address 0xDDDD Remote SPIsend 0b11011101 SPIsend 0b10101010 Source PAN ID OxAAAA Robot SPIsend 0b10101010 SPIsend 0b10111011 Source address 0xBBBB Robot SPIsend 0b10111011 for int i 0 i lt size i t received SPIsend data i Data payload SPIsend 0b00000000 Frame check sequence FCS 2 bytes SPIsend 0b00000000 at sel 1 return received Note that the destination and source PAN ID and addresses are hard coded because the transmission will only occur between the robot and remote Reading from the frame register is similar to writing to it The following function performs that task and returns the frame buffer as an array of chars bytes char read _ frame void char read char store 128 0 char frame_length at sel 0 SPIsend 0600100000 Command byte for Frame buffer read access frame length SPIsend 0b00000000 Read in PHR byte stating how many bytes are in the buffer u for int i 0 i lt frame _ length 1 i Iterate through frame length 1 last byte is lqi if i gt 127 i 127 read SPIsend 0b0000
34. nstrated the proper functioning of our circuitry When our final motor system was assembled testing was done by driving the robot around on both a smooth surface and on grass at variable speeds Our initial testing showed an issue with a power surge related to rapidly increasing the speed of the motors We found that slamming the joysticks forward caused the robot board with the microcontroller to fault and we believed this to be the result of a power spike from ramping up the motors too rapidly We decided to remedy this problem by running the motors and the robot board of separate power supplies We altered our design so that the motors were supplied by the main 12V battery while the robot board was powered at 12V by aAA battery pack This was unable to prevent hangs in the robot board and so we tried as a second solution to add an additional button to the joystick which when pressed would be able to reset the robot board and allow the robot to continue to function The testing of the marking system required ensuring the ability of the solenoid to fire with the circuitry designed on the robot board and the ability of the solenoid to release paint from the spray can which would mark the position of a detected mine Our initial testing of the system found that the FDD3N40 MOSFET chosen four initial design which had an maximum amperage rating of 2A was unsuitable for activating the solenoid We determined that the button signal was properly reaching the ga
35. ntation they should be placed in so that there would be no dead zones or areas underneath the robot where a mine could be present but no detected and so that they would not interfere with each other or any other robot components and only detect external metal Testing resulted in finding a triangular position which satisfied all of the requirements and which determined the height at which the spray paint can had to be mounted above the rear metal detector Testing of the frame apart from the metal detectors involved ensuring that space was available for each component could be securely mounted and that the material chosen would be sufficiently sturdy for our application Testing confirmed our initial design in both of these areas Our final mechanical system to be tested was the joystick and resulting joystick enclosure Our initial plan for the joystick was to use the joystick board designed by the mechanical engineers as had been recommended to us by Prof Schafer Upon receiving the board we found that it would not be sufficient for our design as we needed additional circuitry in place for both our buttons and our landmine marking LEDs This led to the design of a joystick enclose which had used the joysticks from the mechanical engineers board but which had both buttons and the landmine marking LEDs custom mounted and connected to additional circuitry in a breadboard 3 2 Software Integrated Testing Testing of the software required testing
36. ocontroller Connection Microcontroller Joysticks Motor Controller Buttons Motors Figure 1 System Block Diagram As seen in the figure above there are two main components to the overall system the main robot and the remote control The robot micocontroller takes inputs from the metal detection system and controls the output to the marking system and the motor controller system The remote microcontroller takes input from the joysticks and the buttons and sends output to the LEDs on the remote board Both the robot and remote microcontrollers communicated to one another wirelessly 2 3 Detailed operation of Marking System The marking system operates through a solenoid pushing the nozzle on a can of spray pain The solenoid is connected to a twelve volt battery pack through a MOSFET which is controlled by the microcontroller When the button on the remote control is pressed the remote sends a signal over the wireless connection to the microcontroller The microcontroller sends a five volt high signal to the MOSFET which then allows current to flow through the solenoid The solenoid contains a coil of wire when current runs through it a magnetic field is generated which pushes the pin outwards The pin pushes a large lever which depresses the nozzle to activate the spray paint can The lever gives the solenoid the necessary torque to depress the nozzle of the spray paint can The spray pain goes through the center of the metal dete
37. off Enable peripheral interrupts Enable INT pin bO Cirq interrupt Reset Atmel part before setting SPI registers at_rst delay_ms 5 at_rst 1 SPI config registers volatile bit smp SSPSTAT 7 0 volatile bit cke SSPSTAT 6 1 to active clock state volatile bit sspen SSPCON1 volatile bit ckp SSPCON1 4 volatile bit sspm3 SSPCON1 volatile bit sspm2 SSPCON1 volatile bit sspm1 SSPCON1 volatile bit sspm SSPCON1 iol SSrnNw u ll eres Input data sampled at end of data output time SPI clock selecte bit Transmit occurs on transition from Idle Serial Synchronous Enable bit Clock Polarity Select bit Idle state for clock is low level SSPM lt 3 0 gt Synchronous Serial Port Mode Select bits 0000 SPI Master mode clock FOSC 64 Enable SPI output sspen 1 Enable global interrupts volatile bit gie INTCON 7 1 End configuration code while 1 Perform A D conversions on the two joysticks vola vola vola vola vola vola vola SAID SO vola vola vola vola vola vola while go done tile bit tile bit tile bit tile bit tile bit tile bit tile bit tile bit tile bit tile bit tile bit tile bit tile bit chs3 ADCONO 5 chs2 ADCONO 4 chs1 ADCON 3 chs ADCON 2 adfm ADCON2 7 acqt2 ADCON2 5 acqt1 ADCON2 4 Il Il HR acqt ADCON2 3 adcs2 AD
38. ontrol and Remote Control Board Schematic g oe 24 ri rere ss it gt BE Senior Design Spring 2011 Robot Control and Remote Control Board Layout 25 INN INN GENN Nee ENING ISN NN 5 PINS EIN 2S NN NA VN WN ZX ALN NN ALN AW ALN VN NL RIEN NN NEL N Ne NNN VUVIV_LI VM_ANV_AH NVA Team Robot Rangers Version 1 2 Main Robot 5 2 11 7 include lt system h gt define CHAN 11 DATA DATA DATA DATA pragma pragma pragma pragma _CONFIG1H _OSC_INTIO2_1H _CONFIG2H _WDT_OFF_2H _CONFIG3H _MCLRE_ON_3H pragma CLOCK_FREQ 8000000 Global variables volatile bit at_sel PORTB 4 volatile bit at_rst PORTB 5 volatile bit at_slp PORTA 3 volatile bit md1 PORTE volatile bit md2 PORTE 1 volatile bit md3 PORTE 2 volatile bit sspif PIR1 3 volatile bit int if INTCON 1 bool readytoread void interrupt void volatile bit bf SSPSTAT Q if sspif 1 sspif 0 else if int if 1 intOif 0 readytoread 1 char SPIsend char sent_byte char returned_byte sspif sspbuf sent_byte while sspif 0 returned_byte sspbuf sspif Q return returned_byte char read_register char reg char tosend 0610000008 char ans at_sel tosend tosend reg SPIsend tosend ans SPIsend 0b00000000 at_sel 1 return ans INA NENENLNEN eu Ze NENG AE Ae RE ON LVN OP ENN LEN EN VN WN AX ANCA VN VN A
39. p2m3 CCP2CON 3 1 The next 4 bits correspond to setting volatile bit ccp2m2 CCP2CON 2 1 CCP2 into PWM mode volatile bit ccp2m1 CCP2CON 1 Q f 1 volatile bit ccp2m CCP2CON 0 PL Audi Timer2 config registers for PWM volatile bit t2ckps1 T2CON 1 0 The next two bits correspond to volatile bit t2ckps T2CON 1 the TMR2 prescalar value of 4 volatile bit tmr2on T2CON 2 1 Enable Timer2 Start the PWM output Enable SPI output sspen 1 Interrupt config registers volatile bit int ie INTCON 4 1 Enable INT pin b Cirq interrupt volatile bit peie INTCON 6 1 Enable peripheral interrupts Enable global interrupts volatile bit gie INTCON 7 1 End configuration code Start off by waiting for a packet from the remote enable_irg_3Q receive CHAN CONFIRMED that it s getting to state 0x06 whileC readytoread Don t do anything until the remote starts talking received read_frame Read the first packet from the remote readytoread delay_ms 5 while 1 Read our data from the metal detectors to_send Q md1 Load up to_send with the value of MD1 to_send 1 md2 Load up to_send with the value of MD2 to_send 2 md3 Load up to_send with the value of MD3 Begin wireless dance disable_irg_3Q transmit to_send 3 sequence CHAN Transmit the robot info on the value of CHAN sequence sequence 1 delay_ms
40. receive CHAN while readytoread received read _frame readytoread 0 Note the array to_send contains the information gathered from the sensors on the robot remote The delay is added after the transmission sequence before enabling the interrupt to ensure a false interrupt is not sent while the transceiver chip is still transmitting the data from 14 the previous command Since the program flow continuously cycles through this code the robot and remote will continuously be exchanging and updating each other s information On the remote side code was added to count the amount of time that has elapsed since it sent it s last packet If it waits for a response from the robot for too long it assumes that the robot did not receive the packet and re sends the data and begins to wait for a response again disable irq 3 transmit to_send 3 sequence CHAN Transmit the remote info on the value of CHAN sequence sequence 1 delay ms 1 enable irq 3 receive CHAN Put the Atmel chip in a state to receive data while readytoread hangcounter hangcounter 1 if hangcounter gt 100000 I you ve waited to long break out and retransmit failedtoconnect 1 readytoread 1 Wait here for a response from the robot hangcounter 0 received read_frame Read the data from the robot readytoread 0 100 ms delays were also added in the main program loop of both the robot and remote to p
41. revent the over transmission of wireless packets With the system updating itself about 10 times a second there is still plenty of resolution in terms of data collection and lag time Also power consumption is reduced by limiting the rate at which wireless packets are sent 2 7 Detailed operation of remote control system The remote control system just like the main robot system has 3 main functions that it performs It a gathers information from it s sensors and organizes them into an array of bytes b transmits the array containing the sensor information to the robot and waits for a reply and c updates the LEDs with the information received from the robot This cycles continuously in an infinite loop The first and simplest sensor collection is reading the state of the button press on the control board The button is to signal when the marking system should be activated This is achieved by simply setting the I O pin in the microcontroller that the button is connected to as an input and reading the state of the input pin The button circuit is configured to be ground when the button is not pressed and a high voltage when the button is pressed The joystick potentiometer sensor reading is more involved because it requires an analog to digital A D conversion There are three registers associated with A D conversion on the 18f4321 microcontroller They are ADCONO ADCON1 and ADCON2 ADCOND is responsible for selecting which analog input yo
42. se the robot to tip over It would still be a design challenge to assure that the motor would be able to produce enough torque to depress the paint can nozzle but it is another option that should be explored 6 Conclusions The problem presented by landmine detection is a serious issue which requires a sophisticated system to properly be properly addressed While our system is able to be improved in several aspects in order to completely satisfy as a solution to landmine detection and marking it offers a prototype which demonstrates at a basic level the features which a commercial solution would use Our system is wirelessly controlled by a remotre board which can be operated out to a safe distances of 50m With this wireless control the robot is able to scan the minefield and identify to the operator the location of landmines by transmitting the singals of metal detectors mounted on to the robot to the remote and using them to light up landmine identifying LEDs Our system lacked the budget and sophistication to demonstrate a robot which could selectively scan for landmines among other metallic objects or which could traverse any terrain in which landmines might be present however we were able to demonstrate a system which was able to traverse natural terrain similar to what might be present in a field and which could identify underlying metallic objects Bringing our system to commercial grade would require addressing several issues within our des
43. ssion char SPIsend char sent_byte char returned byte 11 sspif 0 Interrupt flag set low sspbuf sent_byte Load buff with data to send while sspif 0 Wait for interrupt indicating send complete returned byte sspbuf After interrupt buffer contained returned data sspif 0 Clear interrupt flag again for good measure return returned byte Function returns received information After proper data transmission has been established using the SPI interface the next step is write data to the appropriate registers on the Atmel wireless transceiver chip to enable it for radio transmission In the software several functions were written to simplify and enhance the code readability The first function is used to write to the transmit state register on the Atmel chip The transmit state register holds the state variable for the transceiver s internal state machine It must be set accordingly in order for the transceiver to transmit properly void set_trx_state char cmd at_sel 0 SPIsend 0b11000010 We want to write to register 0x02 TRX_STATE SPIsend cmd at sel 1 return The next function writes to the IRQ_MASK register which controls which interrupts are going to be active on the wireless transceiver chip For our design we only wish to use the IRQ_3 interrupt which signals when the frame buffer has finished receiving an incoming packet and is ready to read The following functions set or clear tha
44. sssnnssssnnnsnnnsnnnnnssnnnnennnnnennnnnene 8 2 5 Detailed Operation of Motor Control System sssssssosssssonsssssnnssnnnnennnnnennonnennnnsennen 8 2 6 Detailed Operation of Wireless Communication System sssccssssssessssesees 11 2 7 Detailed Operation of Remote Control System usssosssssssssssonsesnnnnennnnsennnnsennnnnene 15 2 8 Detailed Operation of Main Robot System sssssssssssssnsssnnsssnsnnsssnnnssnnnnsnnnnnennnne 16 2 9 Detailed Operation of SPI Interface ssssssssossssonsssnsnnssnsnnsnnnnnsnnnnnennnnnennnnnnnnnnne 17 Jz System Integration Testing csseiscsassccssesssscsvonssecsssessac soonssecosvebsucessesbectocespecenosioncsssuspevareuscerscsess 17 3 1 Mechanical Integrated Testing ccccccciicciensessesscsesssseceescssnsosessdeccassvorteovestecnocscenentucsbans 17 3 2 Software Integrated Vesting ci ccsscccsdceccasssasnossecssssscbosvoonsssgesessoveussougedsooucdoousesdercsvasasass 19 3 3 Overall Requirement Satisaction esoussssonssssnnssnsnnssnsnnnsnsnnnsnsnnsnnnnnsnnnnnsnnnnnssnnnnsnnnne 20 Ae ser Manwal o2 32 een ie 20 4 1 How to Install Your Product nennen 20 4 2 How to Set Up Your Product uussssssssossssonnsssnnssnnnnssnnnnsnnnnnennnnnennnnnennnnnennnnsnnnnnnene 21 4 3 How the User Can Tell if the Product is Working ssssssssssssonssssnnesnnnssnnnnsesnnnnene 21 4 4 How the User Can Troubleshoot the Product sssssssssssssonsssnnnnssnnsennnnnennonsennunne 21 5 To Market
45. sure the pin has not fallen out of the 21 solenoid and the lever is making contact with the nozzle Finally check the voltage of the main battery If it drops too low the solenoid will not be able to activate the spray can Recharge the battery 5 To Market Design Changes Before going to market several design changes would be necessary in order to make our solution a more viable option for our customers The construction of the frame would be weather and water proofed in order to provide greater durability in multiple environments that may contain land mines The design of the frame itself would be more compact but still allow for an increased range in detection so that fewer passes are needed over a given search area A higher ground clearance would allow for the ability to search areas with more rugged terrains Another area of focus would be the user interface with the remote control and how the user controls these interactions with the robot This would include an increase in the wireless communication range so as to keep people further from data Also improved power management and voltage monitors would inform the user when the robot s battery needs to be recharged In terms of the marking system instead of using a solenoid to activate the spray paint can nozzle a solution using either a DC or stepper motor would be designed and implemented This would solve the problem of having a large lever on the back of the robot that may cau
46. t it has to accomplish 3 main tasks It collects the metal detector input information through the reading of a 16 digital input port on the microcontroller Since the metal detector output is around 9 volts the signal is run through a unity gain amplifier buffer that uses an op amp circuit that can reduce input voltages down to the system voltage of 5 volts The buffer also isolates the metal detection system electrically so that the microcontroller will not draw any current from the metal detector and interfere with its function The state of each metal detector is gathered and organized into an array that is to be transmitted to the remote see the wireless subsystem description section for more information about the transmission process After the transmission of the sensor data and the reception of the packet from the remote the received information is used to update the PWM duty cycle and phase direction see the motor control subsystem description as well as to drive the gate signal of the solenoid MOSFET see the marking subsystem description This software continues on an infinite loop and will continue until either the robot or the remote is turned off 2 9 Detailed Operation of SPI Interface SPI Serial Peripheral Interface is the synchronous serial data link used to allow the microcontrollers to communicate with the ATMEL transceiver chips The microcontroller selected allows for SPI communication and thus the microcontroller simply
47. t register accordingly void enable irq 3 void at sel 0 SPIsend 0b11001110 We want to write to register 0x0E IRQ MASK SPIsend 0b00001000 Setting bit 3 enable IRQ 3 TRX_END at_sel 1 return void disable irq 3 void at_sel 0 SPIsend 0b11001110 We want to write to register 0x0E IRQ MASK SPIsend 0600000000 clear bit 3 disable IRQ 3 TRX END at_sel 1 u u return Once the interrupts have been properly enabled you must select a channel to transmit on by setting the appropriate register The following function performs that task void select channel char channel at sel 0 SPIsend 0b11001000 Command byte for Register Write Access SPIsend channel Channel select byte at_sel 1 return 12 Two function were also written to read and write from the frame buffer on the Atmel transciever chip These two functions are significantly more complicated than the previous because the frame buffer must be constructed according to the IEEE 802 15 4 specifications The following function writes information to the frame buffer and completes the preparation necessary needed for transmission char write frame char data char size char seq char received at_sel 0 SPIsend 0b01100000 Frame write access command byte SPIsend size 13 PHY header PHR with MSB reserved frame length SPIsend 0b00000000 Reserved 7 IntraPAN 6 ACK Request 5 Frame Pendi
48. tall your product Your robotic landmine detector comes fully assembled you only need to install the battery First ensure the battery is fully charged using a voltmeter then attach the positive and negative leads to the red and black terminals of the battery respectively Attach a nine volt battery to the remote control and the system is ready to go 20 4 2 How to set up your product Remove the spray paint can and shake vigorously This ensures that the markings will be as visible as possible and should be performed before every use of the robot Move the switch on the main board inside the robot to the on position Then hit the reset button on the main board and the reset button on the remote control You robot is now ready to begin sweeping the minefield 4 3 How the user can tell if the product is working To move the robot push the joysticks in the desired directions Pushing both forward on both will move the robot forward and pulling both will move the robot backwards Pushing one stick forward and one backwards will rotate the robot in place for example pushing the left stick forward and pulling the right stick backwards will rotate the robot clockwise Pull the left stick and push the right to rotate counter clockwise If the robot performs all of these motions the motors and treads are functioning To test the detection system take a large metal object such as a watch or screwdriver and move it back and forth under each m
49. te and so the solenoid was unable to flow current to the solenoid To redesign the system we connected a 30 amp maximum MOSFET from the storage room which was able to flow current from the robot board to the solenoid Testing of the spray can however revealed a separate issue with our initial design When the solenoid chosen was directly connected to our robot battery it was able to generate enough force to depress the spray can button and release paint however when supplied by the robot board it was unable to generate a sufficient force In order to generate a larger force on the spray paint can we installed a 1 5 lever on the top of the robot so that the solenoid would be mounted to the top of the lever and the lever would increase the force of the solenoid on the button This system ultimately proved to be inadequate for our final design as the position of the lever relative to the head of the button had to be precisely monitored for the system to work when powered from the board As a result the marking system was not able to be demonstrated in our final design The testing of the frame design included testing the ability of the mounted metal detectors to be able to detect mines across the full sweep of the robot and the ability of the frame to securely mount each of the robot components The initial testing of the metal detectors 18 involved experimentally determining the range of their detecting radius so that we could determine what orie
50. the PWM software testing the SPI connection between the microcontroller and the Atmel chip and testing the wireless transmission to ensure that all data was being properly sent and received by both the control board and the robot board The PWM software was initially tested using our kit board and motors supplied by the storage room Testing revealed that our first design of the PWM code was causing either a negative or positive signal to be constantly sent to the motor so that at rest the motor was being sent a positive signal half of the time and a negative signal half of the time This was a highly inefficient use our battery and putting undue strain on the motors therefore the code was modified so that in each direction either a pulse was being sent to move the motor or no signal was being sent In order to be able to set up the wireless connection between the remote board and the robot board we had to first ensure that we were able to properly communicate between our microcontroller and the ATMEL wireless chip using SPI Testing of our SPI connection involved writing to registers in the ATMEL chip and then reading them back to ensure that data was properly being sent and received For testing purposes information being sent and received on each pin was monitored by connecting the pins to the USB Logic Analyzer Testing of the full wireless software involved testing our code s ability to properly send and receive packets of information contain
51. tion of the Atmel AT86RF231 wireless transceiver chip The microcontroller interfaces with the Atmel transceiver chip using a serial peripheral interface SPI The 18f4321 can be configured to output SPI compliant data SPI consists of 4 basic signals Master Out Slave In MOSI Master In Slave Out MISO a clock signal and a select signal In addition to the four main SPI signals the communication channel to the transceiver chip also utilizes a sleep trigger signal a reset signal and an interrupt signal Below is the configuration code to configure the microcontroller to output SPI data volatile bit smp SSPSTAT 7 0 Input data sampled at end of data output time volatile bit cke SSPSTAT 6 1 SPI clock selecte bit Transmit occurs on transition from Idle to active clock state oO Il fo volatile bit sspen SSPCON1 Serial Synchronous Enable bit volatile bit ckp SSPCON1 4 0 Clock Polarity Select bit Idle state for clock is low level volatile bit sspm3 SSPCON1 3 0 volatile bit sspm2 SSPCON1 2 0 SSPM lt 3 0 gt Synchronous Serial Port Mode Select bits volatile bit sspm1 SSPCON1 1 1 0000 SPI Master mode clock FOSC 64 II oO volatile bit sspm0 SSPCON1 0 With this code implemented the next step is to write your information you wish to transmit over SPI to the sspbuf register Below is a function written to send data out over the SPI interface and return the data received after the transmi
52. u wish to convert and also contains the enable and start bits for A D conversion ADCON 11 is responsible for setting which input pins are configured as analog input and which are configured as digital ADCON2 is used to configure 15 several aspects regarding the output of the conversion including setting the acquisition time and setting the A D conversion clock The software then sets the conversion start bit and waits for the bit to go low The microcontroller will set the bit low when the conversion process is finished and is ready to be read The value of the conversion is then read and stored into the array that is to be transmitted After the first conversion a short delay is added before the the next analog input is selected the second joystick and the conversion process starts again and the second value is loaded into the the array The following code accomplishes this task volatile bit chs3 ADCONO 5 0 Select channel 0 J1 volatile bit chs2 ADCONO A 0 volatile bit chsl1 ADCONO 3 0 volatile bit chs0 ADCONO 2 0 volatile bit adfm ADCON2 7 0 adresh will contain the 8 MSBs of the result volatile bit acqt2 ADCON2 5 1 The next 3 bits set the A D aquistion time to volatile bit acqt1 ADCON2 4 1 20 Tad Longest possible aquisition time volatile bit acgtO ADCON2 3 1 volatile bit adcs2 ADCON2 2 0 The next 3 bits set the A D conversion clock volatile bit adcsl ADCON2 1 0
53. ut volatile bit trisd6 TRISD 6 SR2 D6 out volatile bit trisd7 TRISD 7 Phase2 D7 out volatile bit trisb3 TRISB 3 1 FF12 B3 in volatile bit trisb6 TRISB 6 1 FF22 B6 in Init PWM signals ccpril Duty cyclel initialized to latd 1 Reseti is high stays this way latd 1 1 PWML1 is high stays this way latd 2 1 SR1 is high stays this way latd 3 Phasel is initialized to ccpr2l Duty cycle2 initialized to 0 latd 4 1 Reset2 is high stays this way latd 5 1 PWML2 is high stays this way latd 6 1 SR2 is high stays this way latd 7 Phase2 is initialized to PWM1 CECCP1 config registers volatile bit plm1 CCP1CON 7 Single Output P1A volatile bit p1m CCPI1CON 6 volatile bit dc1b1 CCP1CON 5 Q Bit1 of duty cycle1 always for 8bit resolution volatile bit dc1b CCPICON 4 Q Bit of duty cyclel always for 8bit resolution volatile bit ccp1im3 CCP1CON 3 1 The next 4 bits correspond to setting volatile bit ccp1im2 CCP1CON 2 1 all PWM outputs CECCP1 to be active high volatile bit ccp1im1 CCP1CON 1 Q P Pig volatile bit ccp1m CCP1CON 0 J PWM2 CCP2 config registers volatile bit dc2b1 CCP2CON 5 0 Bit1 of duty cycle2 always for 8bit resolution volatile bit dc2bQ CCP2CON 4 Q Bit of duty cycle2 always for 8bit resolution volatile bit cc
54. void disable_irg_3 void void select_channel char channel void transmi power on void rec power on for fram J f Mir SEL MOSI MISO SCLK IRQ SLP_T RST Joy at_sel Q SPIsend 0b11001110 SPIsend 0b90000000 at_sel 1 return at_sel SPIsend b11001000 SPIsend channel at_sel 1 return set_trx_state 8 pg 33 set_trx_state 9 write_frame data size seq set_trx_state 2 return eive char channel select_channel channel set_trx_state 8 pg 33 set_trx_state 6 es return eless SPI pins B4 out 1 1 an ru mo STE A BQ in R A3 out B5 out stick pins tCchar data char size char seq char select_channel channel We want to write to register 0x02 CTRX_STATE We want to write to register Ox E CIRQ_MASK Setting bit 3 enable IRQ_3 CTRX_END We want to write to register x E CIRQ_MASK clear bit 3 disable IRQ_3 CTRX_END Command byte for Register Write Access Channel select byte channel 0x08 TX_OFF we have to go to this state first after a 0x09 PLL_ON transmission on 0x02 TX_START 0x08 TX_OFF we have to go to this state first after a 0x06 RX_ON Center state RX_ON and continuously check J1 J2 AQ in A1 in Button pin Button D in LED pins LED1 D1 out LED2 D2
Download Pdf Manuals
Related Search