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1. 2 connections for 5V hobby servos connected to the Arduino s high resolution dedicated timer no jitter 4H Bridges L293D chipset provides 0 6A per bridge 1 2A peak with thermal shutdown protection internal kickback protection diodes Can run motors on 4 5VDC to 25VDC Up to 4 bi directional DC motors with individual 8 bit speed selection so about 0 5 resolution Up to 2 stepper motors unipolar or bipolar with single coil double coil or interleaved stepping Pull down resistors keep motors disabled during power up Big terminal block connectors to easily hook up wires 18 26AWG and power Arduino reset button brought up top 2 pin terminal block and jumper to connect external power for separate logic motor supplies Tested compatible with Arduino Mega 1280 amp 2560 Diecimila Duemilanove and UNO Download the easy to use Arduino software library check out the examples and you re ready to go eeee Fig 4 2 5 5 Servo Extension Cable 30cm 12 long ID 972 1 95 39 Fig 4 2 6 6 ATMEGA256xx 256k Flash Memory ATMEGA2560 ATmega2560 100 Pin 16MHz ATMEGA2561 ATmega2561 100 Pin 16MHz SSE Et osc remo a sum A Fig 4 2 7 7 Fig 4 2 8 8 9 Degrees of Freedom Razor IMU 124 95 SEN 10736 RoHS Description The 9DOF Razor IMU incorporates three sensors Add to Cart an ITG 3200 triple axis gyro ADXL345 triple axis a
2. The intent of the software systems control was to maintain a safe dynamic range on the robot arm s links travel to avoid damage to the arm from the human operator s motions exceeding the robot arm s work volume Spatial resolution of the robot arm servos were roughly determined to be about 0 36 degrees for a 90 degree servo travel and 0 72 degrees for a 180 degrees servo travel For practical purposes the human in the loop operator has to maintain safe operation of the arm The Helping Hand operated over 10 input signals 3 x y z axes from each sensor s accelerometer data and a signal from the end effector controller all of which were used to generate 7 output signals to drive the servos for a total of 17 signals If the gyroscope data had been combined with the accelerometer data the system would have been operating on 19 input signals and the same 7 output signals for a total of 26 signals Shown next is a sample of data from an mpu 6050 showing both accelerometer and gyro data values 124 Read accel temp and gyro error accel x y z 8600 240 14660 temperature 26 529 degrees Celsius gyro x y z 200 12 41 MPU 6050 Read accel temp and gyro error 0 accel x y z 8444 132 14732 temperature 26 482 degrees Celsius gyro X y Z 151 8 33 MPU 6050 Read accel temp and gyro error 0 accel x y z 8508 148 14920 temperature 26 482 degrees Celsius No line ending 9600 baud
3. 10 4 System Budget AL5D robot arm 180 AVR Programmer 130 7 servos 100 2 PCBs 100 Elbow joint 30 4 MPU 6050 20 2 Stencils 20 Resistors 15 Capacitors 10 Header pins 10 Frame materials 10 Flux 8 Solder boards 8 Velcro 5 Solder paste 3 Pin headers 3 Solder 2 Pin jumpers 1 Cable Free ATxmega128A4U Sample New power supplies 60 125 Total 715 GOAL 800 10 5 Project Review Successes and Errors Prototype development was quite useful for acquiring many components used in the final construction and testing of the metal arm The metal arm selected performed well mechanically as did most of the analog and digital servos acquired during the building of the Helping Hand The sensor boards and microcontroller unit designed by project team member Eric Donley and built by the team worked very well Without question a severe error was made in changing the design directly to a 6 1 more human like arm without developing from the original metal arm acquired of 4 1 design Another error was not incorporating gyroscopic data into the motion control software algorithms Because of time constraints accelerometer data only from the six axis three gyroscopic angle axes and three accelerometer translational axes mpu 6050s were used in the motion tracking algorithms Much smoother motion and more accurate motion tracking cou
4. POWER 1 DODOOODD va oo TIng Toor a a ATxmega128A4U MCU schematic 95 P61877 Project completed ATxmega128A4U MCU 96 Power Supply Single PC 350 Watt P S configured as a Shared DC Power Bus at 5 Volts for servos and dc to dc regulated to 3 3 Volts for sensors and micro controller unit Connection board tess tie L sYa 5V to 3 3V Voltage Regulator 7 4 Software Integration Most of our project involved trying to successfully manipulate the sensor data through the microprocessor on the control board to drive the motors on the robot arm Programming integration began immediately on March 25 with the first prototype test of one gyro sensor driving one motor of the robot arm This was achieved using an Arduino Mega 2560 From there a pcb board was designed to allow an Atmel ATxmega128A4U micro controller to be programmed to control the arm Control software was created using the Atmel libraries and example code for controlling the sensors found online The code begins with initializing all of the necessary subsystems of the microcontroller such as the pwm and IO pin directions It then moves on to initialize the sensors by removing them from sleep mode setting their clock source bandwidth the sampling rate and range for the gyro and accelerometer After the sensors are initialized data is then pulled from the sensors and converted to a 16 bit integer and then compensation for the hand and fore
5. Serial print gyroscope y DEC Serial print Serial printIn gyroscope z DEC Serial flush delay 100 L3GD20 Code References for 4915 https github com adafruit Adafruit_L8GD20 This is a library for the Adafruit Triple Axis Gyro sensor 131 Designed specifically to work with the Adafruit L8GD20 Breakout gt https www adafruit com products 1032 These sensors use 12C or SPI to communicate 2 pins 12C or 4 pins SPI are required to interface Adafruit invests time and resources providing this open source code please support Adafruit and open source hardware by purchasing products from Adafruit Check out the links above for our tutorials and wiring diagrams Written by Kevin Townsend for Adafruit Industries BSD license all text above must be included in any redistribution To download click the DOWNLOADS button in the top right corner rename the uncompressed folder Adafruit_L8GD20 Check that the Adafruit_L3GD20 folder contains Adafruit_L3GD20 cpp and Adafruit_L8GD20 h Place the Adafruit_L3GD20 library folder your Arduinosketchfolder libraries folder You may need to create the libraries subfolder if it s your first library Restart the IDE Adafruit_L3GD20 examples Adafruit_L8GD20_test PHRASE IOI IOI ISI II II II This is an example for the Adafruit Triple Axis Gyro sensor Designed specifically to work with the Adafruit L8GD20 Breakout gt https www adafruit com pr
6. 1x USD 135 40 5x USD 129 98 25 x USD 124 78 Options Reach 75 gt Version Hardware Only View product availability oa 4 1 Degree of freedom robotic arm 10 25 median reach Servo Motors sold separately Electronics and software sold separately Wrist rotate option sold separately The Lynxmotion AL5D 4 Degrees of Freedom Robotic Arm Hardware Only line of robotic arms deliver fast accurate and repeatable movement Each arm features base rotation single plane shoulder elbow wrist motion and a functional gripper The wrist rotate feature which comes in a lightweight or heavy duty option is sold separately Llynxmotion designed an affordable system based on a time tested rock solid design that will last and last Add your own servos and electronics to complete the kit The aluminum robotic arm is made from Lynxmotion s Servo Erector Set components for the ultimate flexibility and expandability The kit consists of black anodized aluminum brackets Aluminum tubing and hubs custom injection molded components and precision laser cut Lexan components For a list of suggested servos see RB Lyn 274 Fig 4 2 2 43 and 3 Lynxmotion Wrist Rotate Upgrade Light Weight Product code RB Lyn 273 Qty Price 1x USD 30 34 10x USD 29 73 20 x USD 29 14 t A in Stock r Fig 4 2 3 and probably not 4 MechaTE Robot LEFT Hand Product code RB Cus 02 Qty Price 1x USD 900 00
7. Communication Monitors Price Phidget Advanced Servo 8 USB Position 90 00 8 Motor Power ServoCity 8 Servo 8 USB serial Position 69 99 PC Controller Cytron 8 Channel Servo 8 USB UART Position 20 65 Controller Table 4 2 2 Motor controllers considered for this project 4 2 3 Gyros HOW GYROS WORK MEMS micro electrical mechanical systems gyroscopes measure the rate of change around an axis which means to determine the amount of angular change which is what is needed for the robot arm control the output of the gyro has to be integrated to find the amount of angular change 1 The gyroscopes are available in basic IC chip format The physics of operation of the gyro is a measured Coriolis force that occurs when a massive object has both translational and rotational motion simultaneously If a rotational motion is applied perpendicularly to the direction of velocity of an object a Coriolis force is developed by the right hand rule 49 perpendicular to both the velocity vector and the angular momentum vector A capacitive sensing mechanism measures the force and the measurement is used to determine the rate of change of angle of motion Fi 2m x v Fig 4 2 5 1 This is an oversimplification of the actual MEMS gyro design which uses two masses connected by a spring gt AC 0 F coriolis Fig 4 2 6 1 50 Fig 4 2 7 2 MEMS implementation of above two masses
8. Referencing the Edge 535 Fig 4 2 1 above our design job is to replace the existing simple mechanical control system of the arm using double pole contact switches to apply either 3V or 3V to each servo motor for clockwise counterclockwise rotation 1 55 Wired Control Box bo Robotic Arm Edge Fig 5 0 1 Mechanical contact solder less pc board control box 1 56 Fig 5 0 2 attached to arm by eight pin ribbon cable 1 57 Fig 5 0 3 the manual control box will be replaced by our own sensor microcontroller motor driver system with control signals generated from the sensors located on the operator s arm 2 58 lt Human arms anatomy diagram showing bones and muscles while flexing 2 D digital illustration On white background Fig 5 0 4 O angle sensors to track linkage motion and force sensor to detect opposing fingers to open and close gripper end effector Our system will be virtually open loop to begin just the sensors on the operator s arm and hand and a control box to interpret the data signals and send motion control signals to the servo motors on the arm a virtual open loop control system The initial performance criteria of the arm are accurate imitation of the operator s arm motion and a smooth tracking motion with minimal time delay Time delay occurs in every electro mechanical system In most cases it is not noticeable but in other cases it can render the system
9. Hexapod and Delta Robots 4 Parallel robots offer greater stability and have the advantage of averaging linkage motion errors compared to serial linkage arrangements like a robot arm that accumulates the errors in each link motion 4 This is something didn t learn in EGN3060 Introduction to Robotics at UCF you can discount this sentence from the total page count but it is still true By definition robot arms are Articulated robots with a mechanical manipulator that looks like an arm with at least three rotary joints 5 There are numerous types of robots defined by body type and the nature of their geometrical motion range such as Cartesian cylindrical polar and even spherical Revolute robots such as the robot arm are considered the most difficult to program offline and the most complex manipulator 5 They are the most difficult to program because they can reach the same location from both above and below a given starting point or reference location with different linkage configurations They are also the most efficient in terms of work area coverage from a given amount of floor space 5 A Cartesian robot has three orthogonal axes x y and z that define a rectangular work geometrical volume or envelope Cartesian robots are much simpler geometry to program and have high volume frequency highly repetitive task use in industry The articulated robot arm operates in a virtual hemispherical volume or work envelop
10. adding an increase in the amount of time to execute as well as all data that is received during this period will be lost Another disadvantage is that extra bits are needed in the data stream to indicate the start and end of useful information These extra bits take up bandwidth 10 5 4 4 2 2 Asynchronous Serial Transmission The baud rate is defined by how many bits are sent per second but baud only has meaning if the two communicating devices have a synchronized clock For example if a microcontroller crystal has a slight deviation of 1 second meaning it thinks 1 second is actually 1 1 seconds long This could cause your baud rates to be mismatched and fail One solution would be to have both devices share the same clock source but the tradeoff here is you must add extra wires Asynchronous transmission allows data to be transmitted without the sender having to send a clock signal to the receiver Instead the sender and receiver must agree on timing parameters in advance and special bits are added to each word which are used to synchronize the sending and receiving units When a word is given to the UART for asynchronous transmissions a bit called the start bit is added to the beginning of each word that is to be transmitted The start bit is used in alerting the receiver that a word of data is about to be sent which then forces the clock in the receiver to synch with the other clock in the transmitter These two clocks must be accurate e
11. figure eventually will add a calibration step that can be used to estimate the gain offset parameters to get better calibration values The next step was to make some cumulative angle measurements printed out a protractor image and then turned the gyroscope back and forth between 0 and 180 107 Then integrated the z rotation angle to compute the absolute angle The idea is that the gyroscope produces a delta angle call it 6 Eases 100 120 0 So 100 150 200 250 300 350 400 450 108 Note sample test code in appendix C refers robot calibration section 8 1 1 Accessed Dec 4 2012 About Repeatability http www strobotics com repeat htm 2 Accessed Dec 4 2012 JCGM 200 2008 International vocabulary of metrology Basic and general concepts and associated terms VIM http www bipm org utils common documents jcgm JCGM_200_2008 pdf 3 Accessed Dec 4 2012 http en wikipedia org wiki File Accuracy_and_precision svg 4 Accessed Nov 14 2012 Using the L8G4200D gyroscope with the Arduino http ardadv blogspot com 2012 05 using I3g4200d with Arduino html 5 Accessed Dec 4 2012 ISO 9283 1998 Manipulating industrial robots Performance criteria and related test methods 162 http www iso org iso catalogue_detail htm csnumber 22244 6 Accessed Dec 4 2012 ANSI RIA R15 05 2 1992 R1999 67 http webstore ansi org RecordDetail aspx sku ANSI 2FRIA R15 0
12. g 111 Fig 8 3 1 The force resistance graph above shows a virtual switch like action when the initial pressure force increases from zero to about 30 grams force and the resistance decreases 100k ohms to about 20k ohms Generally the greater the resistance the lesser the applied force The 1 5 inch square FSR has been acquired and tested with an ohmmeter and does OL on the highest scale at zero applied force and then rapidly decreases to virtually zero resistance if heavy pressure is applied The force sensing resistor datasheet fsr_datasheet pdf has some helpful info regarding implementing the force sensor 3 Suggested Electrical Interfaces Basic FSRs RM VALUES 100k e Wa m la _ Jh VOUT V vouT F vs V for Part No 402 Interfink Force Tester 1 cm circular flat metal actuator FORCE g Fig 8 3 2 FSR Voltage Divider 3 For a simple force to voltage conversion the FSR device is tied to a measuring resistor in a voltage divider configuration The output is described by the equation VOUT V 1 RFSR RM In the shown configuration the output voltage increases with increasing force If RFSR and RM are swapped the output swing will decrease with increasing force These two output forms are mirror images about the line VOUT V 2 112 The measuring resistor RM is chosen to maximize the desired force sensitivity range and to limit current The cur
13. images are CC BY NC SA 3 0 interface Additional features include an embedded temperature 49 95 price sensor and a 2 accurate internal oscillator 44 96 10 units Fig 4 2 2 37 Arduino Mega 2560 R3 Atmega2560 assembled Mega ID 191 Manufactured by Smart Projects 65 00 ar Qty Discount 1 9 65 00 10 99 58 50 100 52 00 ARDUINO ee Add to Cart fi ADD TO CART 88 IN STOCK ADD TO WISHLIST Description Technical Details Blog Flickr Distributors NEW VERSION This is the Arduino Mega R3 The Arduino Mega 2560 is a microcontroller board based on the ATmega2560 datasheet It has 54 digital input output pins of which 14 can be used as PWM outputs 16 analog inputs 4 UARTs hardware serial ports a 16 MHz crystal oscillator a USB connection a power jack an ICSP header and a reset button It contains everything needed to support the microcontroller simply connect it to a computer with a USB cable or power it with a AC to DC adapter or battery to get started The Mega is compatible with most shields designed for the Arduino Duemilanove or Diecimila Fig 4 2 3 3 Dual H Bridge Motor Driver for DC or Steppers 600mA L293D ID 807 2 50 Fig 4 2 4 4 38 Adafruit Motor Stepper Servo Shield for Arduino kit v1 0 ID 81 Manufactured by Adafruit 19 50 Qty 1 9 10 99 100 Please en and we wi when this You willo this prod Your Nan Your E m
14. roll Our initial design with the plastic arm does not have the option of roll at the wrist but a rotatable wrist is an option 35 with the Lynx metal arm Accuracy of the robot arm motion is a very important consideration for a motion tracking application such as our arm but quantitative analysis will have to wait until we get the arm actually working Our accuracy requirement is not the traditional repeatability requirement of pick and place robot applications rather an accurate proportional movement of the robot arm to the human operator s arm that is stable and repeatable The end effector of our current robot arm has foam rubber pads on the jaws of the gripper that can easily hold a smooth object such as a pen or pencil between the jaws of the gripper without breaking the object The end effector has a translation open close motion that is driven by another dc motor M1 Sensors The heart of our project is the motion sensors that detect the human operator s arm motion and send the data to the micro controller Sensors are the perceptual system of a robot and measure physical quantities like contact distance light sound strain rotation magnetism smell temperature inclination pressure or altitude Sensors provide the raw information or signals that must be processed through the robot s computer brain to provide meaningful information Robots are equipped with sensors so they can have an understanding of their surrounding e
15. wireless after we can get the wired working A far heavier weight master slave arm is shown last am currently trying to find out how accelerometer and gyroscope sensors can be implemented for our project Haptic robotic arm 1 1 Haptic robotic arm TheYadavanil O Subscribe 19 videos v Fig 3 1 3 Comments light weight looks inexpensive and has combination shoulder elbow plus rotating wrist and pincer gripper 17 Haptic Robotic Arm 2 2 Comment similar to previous except operates by sensor on operator s right hand pointer finger and not by arm movement Haptic Robotic Arm technophiliainfo Subscribe 7 videos vY Fig 3 1 4 Comments Our project is currently more ambitious than these two in that we are trying to control a full 3 linkage arm featuring shoulder to elbow and elbow to wrist linkages and wrist to end effector linkage 6 1 DOF and not just a single linkage from base rotation shoulder to wrist and end effector 2 1DOF and 3 1DOF with wrist rotation on Haptic robotic arm 1 Remote Control of Robot Arm by using Master Slave System 3 Fig 3 1 5 Yes we used Arduino and KRS 788HV Note Kondo KRS 788HV ICS Servo Motor Red Version 99 Comments A way heavier duty and more expensive motor than what we are looking at This project appears more difficult than the first two but it s heavy weight construction makes it cost prohibitive Other projects reviewed more closely included previou
16. 2 HS 422 57 oz in Standard Servo E mail this product to a friend Et gt Size Standard Servo Erector Set ASB xx Standard Scale line Range 180 Voltage 4 8 6 0vdc Torque 57 oz in Weight 1 66 oz Speed 0 16s 60 degrees Full specs Model Number 5422 Price 9 99 Weight 0 14 Quantity 1 Add to Cart Add to Wish List 70 3 HS 422 needed for 29 97 total 3 1 HS 645MG needed at 31 49 3 1 HS 755HB needed at 27 99 3 HS 645MG 133 oz in Standard Servo n gt M Email this product to a friend Size Standard Servo Erector Set ASB xx Standard Scale line Range 180 Voltage 4 8 6 0vdc Torque 133 oz in Weight 1 94 oz Speed 0 20s 60 degrees Full specs Model Number S645MG Price 31 49 Weight 0 12 Quantity 1 Add to Cart Add to Wish List HS 755HB 183 oz in Quarter Scale Servo E mail this product to a friend amp Size Quarter Servo Erector Set ASB 2xx Large Scale line Range 180 Voltage 4 8 6 0vdc Torque 183 oz in Weight 3 88 oz Speed 0 28s 60 degrees Full specs Model Number S755HB Price 27 99 Weight 0 31 Arm upgrade 133 5 servos total at 89 45 222 45 for mechanical equipment upgrade Presumably the electronics will not need any changes other than new voltage and current ratings for the new motors Servos operate on rectangular pulse signals that tell the motor how far
17. 48 bit numbers like 0x024ACE5F3D9B though the 48 bit address though is what is used in actual communication The user overall will choose a device that matches a name given by another user they wish to connect with 5 4 2 3 Radio Frequencies and Channel Hopping What separates Bluetooth from other technologies is that it takes the 2 4 GHz band it occupies and divides into 79 channels which utilize channel hopping techniques These channel hopping techniques create Bluetooth devices that are always changing the frequencies they re transmitting and receiving on This is done in a somewhat random order so that no channels are used more than any others A Bluetooth device that is actively changing channels switches every 625 microseconds 1600 times per second Two Bluetooth devices must hop channels together while communicating so that they will always be transmitting and receiving on the same frequencies 5 4 2 4 Bluetooth networks piconets masters and slaves A piconet is formed when two or more Bluetooth devices are transferring data with one another while channel hopping as stated above occurs A piconet can have a maximum number of 8 total devices connected at one time This brings up the question of how all the devices know to be on the same page A model of communication known as master and slave is employed to resolve this issue A single device on every piconet is chosen as the overall master and this master has two functions Fir
18. 5x USD 864 00 25x USD 829 44 O amp In Stock ye ADD TO MY PREFERRED LIST 53 TELLAFRIEND SHARE af 9 fy Fig 4 2 4 44 Low Profile Axis no servos E mail this product to a friend amp a gt Low Profile Axis LPA 01 includes a brushed aluminum bracket Acetal gears and a Ball Bearing Hub BBH 01 This makes a very strong pivot while only adding 0 486 to the length It works great with all of our other brackets and hubs Easily add waist rotate to a biped a sixth DOF to a Biped leg or wrist rotate to a robotic arm This part makes many interesting and unusual mechanical assemblies possible Model Number LPA 01 Price 24 95 Weight 0 14 Fig 4 2 5 5 Lynxmotion elbow rotation joint above was acquired and added to the final metal arm References 1 Accessed Nov 19 2012 http www robotshop com owi 535 robotic arm edge 1 html 2 Accessed Nov 19 2012 http www robotshop com productinfo aspx pc RB Lyn 268 amp lang en US 3 Accessed Nov 19 2012 http www robotshop com lynxmotion light weight wrist rotate upgrade 5 html 4 Accessed Nov 19 2012 http www robotshop com mechate robot left hand html 5 Accessed Feb 1 2013 http Awww lynxmotion com p 481 low profile axis no Servos aspx 4 2 1 Microcontroller The microcontroller will be used to monitor and store the sensor data from both the operator and the robot and use that data to control the motors in the rob
19. A flow chart of design and testing of Helping Hand indicating accomplished tasks with green check marks is also in section 8 0 10 Funding for the Helping Hand is from the members of the design project and a general target is to not exceed the price of four college textbooks that do not have to be purchased for EEL4915 range 400 800 Milestones beyond an initial working mechanical arm and budget details are outlined in Chapter 9 Administrative Content 11 Attempts were made to contact the author any content cut and pasted from the web but some sources on YouTube have no contact information See Appendix A Chapter 2 Project Description 2 1 Motivation and Goals Motivation for Project As candidates for bachelor of science diplomas in Electrical and Computer Engineering from the University of Central Florida Spring 2013 concern for real working world knowledge and skills led to the choice to design a modern application of an industrial standard robotic application the robotic arm Our application is more sophisticated technologically than the typical robotic arms available from consumer and industrial sources The typical robot arm is basically an open loop control scenario dominated by pre programmed point to 7 point motion and a fixed absolute geometry reference system The Helping Hand is a spontaneous and fluid motion device looking towards a future of ubiquitous and easily programmed human type robotics The Helping
20. Voltage regulators allow the maintenance of a constant stable voltage level This is required for the control board as any electronic noise from the power supply could lead to the robot not properly mimicking the human operator Voltage regulators are also able to perform DC DC conversion allowing a power supply that has a voltage too high for certain components of the control board to still be used to power those components as the voltage regulator can lower the voltage from the supply to the required level This would allow a single battery to power all of the components of the control board as long as voltage regulators are used to lower the voltage to what the components can handle The use of a second battery and voltage regulator will be used to power the motors however to prevent any accidental overload of other components on the control board See the actual power supply design and implementation in section 10 2 System Construction 5 5 3 USB connector A final subsystem of the control board is the USB connector This piece allows the control board to communicate with a computer though the microcontroller For this project this connection will be used to program the microcontroller and possibly monitor the data being passed to and from it during testing to ensure function and accuracy The USB connector will communicate with the microcontroller through the PDI pins which are connected to the program and debug interface of the microcontroller T
21. We probably will not exceed six degrees of freedom Industrial robot arms typically employ five or six degrees of freedom 6 In fact we added an elbow rotation for six rotational plus one translational equals seven total degrees of freedom Accuracy is a little tricky to determine for our human operator arm motion tracking robot arm in that there is not a calculated point to point motion within the work envelope of the robot arms motion Determining the appropriate calibration of proportional movement between the human arm motion and the robot arm will be a significant part of eel4915 after getting the sensors connected and driving the motors in correct qualitative directional response We will probably employ something like potentiometer feedback sensors on the robot arms joints This was not done time constraints prevented any refining of the motion tracking system Repeatability is another problem in that we are not calculating a specific point of geometric location in our quasi open loop application compared to pick and place manufacturing and assembly robot arms However repeatability is also defined as the ability of a robotic system or mechanism to repeat the same motion not just the same specific location 6 We will have to determine some metric for measuring repeatability of the robot arm motions An applicable definition of repeatability for our purposes is a measure of the ability of the transducer sensor t
22. circuit for other fixed output voltages LD1117 C076821 Resulting in a quite effective arrangement the 5 volts is taken off the pc power supply auxiliary standby line pin 9 and is then stepped down by a STM LD1117AV33 dc to dc converter to 3 3 Volts to power the microcontroller unit and the sensors The LITEON PS 6351 2 350 Watt power supply is rated at 18 amps on the 5 volt standby supply 117 Single PC 350 Watt P S configured as a Shared DC Power Bus at 5 Volts for servos and dc to dc regulated to 3 3 Volts for sensors and micro controller unit 5 Volts Connection board tn tie L oe z T 2 5V to 3 3V Voltage Regulator References 1 Accessed April 13 2013 http Awww elmomc com applications Power Supply for Servo Applications htm 1 2 Accessed April 13 2013 http pdf1 alldatasheet com datasheet pdf view 22710 STMICROELECTRONICS LD1117AV33 html Chapter 9 Administrative Content 9 1 Milestones The first milestone was achieved Nov 4 2012 with the successful build of the OWI 535 Robot Arm Edge which has a simple manual controller arrangement Double throw switches that are manually thrown to cw ccw rotate the 5 motors of the 535 arm Mechanical prototype working robot arm completed The second milestone was completed before the spring term started Rotating the base motor M5 of the OWI plastic arm from a simple horizontal rotation of a gyroscopic 3D angle sensor connected through a microcont
23. drain pins and the high state is considered non active Our design will use 1k ohm pull up resistors to 5 Volts lC stands for IIC from Inter IC Integrated Circuits communication technology created by Phillips Semiconductor Corporation in 1982 The technology was standardized in 1992 with version 1 0 and is currently at version 4 0 in 2012 The technology was created to facilitate simpler communication design between different electronic components lC operates on different components by giving each device its own address from a 7 bit address 2 7 128 space with 16 addresses reserved for a total of 112 different components addressable in any given electronic system l C requires only two bus lines as mentioned above each device connected to a micro controller is on a software addressable bus and is given a unique address In our case each sensor will be connected through 12C to the Arduino mega The bus connectivity with 1 C includes collision detection and arbitration to prevent data corruption if two or more masters sensors simultaneously initiate data transfer 1 Our application requires an 8 bit signal output from the sensor SDA pin and clocked on the SCL pin sent to the Arduino micro controller through the 1 C bus Our design will only require a maximum of 5 sensors so we won t be running out of usable addresses The C technology simplifies design of a system of components and facilitates fast implementation of a design into har
24. force measured by the potentiometer would change and the microcontroller would send a signal to the motors to tighten the grip on the object Figure 3 1 1 Luke s Hand 15 3 1 2 Haptic Feedback Robot Hand Another relevant design was found in a senior design project from San Francisco State University The goal of this project was to create a wearable interface for a robot that could provide haptic feedback to the user Haptic feedback is a physical response that allows the user to feel what the robot is doing similar to how an indicator light is feedback for our sense of sight A picture of this project can be seen in figure 3 1 2 The project resulted in a two fingered robotic hand that was controlled by a glove worn by the user The glove had a small servo motor attached to it with a brace placed on the user s index finger The servo motor would provide feedback on its current position and then a microcontroller would send that position to the servos on the hand causing them to move to the same position The servo on the glove had to be modified to allow it to move with the user s finger instead of trying to stay in its set position The servo was rigged to take the slight change in position caused by the users attempt to move their finger and use that as the servo s new set position This allowed the servo to update its own position based on the movement of the user s finger In order to generate the haptic feedback the fingers
25. from the sensors and outputs to the motors The control board must also be able to perform its functions once detached from the computer Chapter 3 Research Related to Project Definition Section 3 0 Introduction A Quick History of the Robot Arm from Unimate to Baxter The robotic arm began industrially in 1961 with the Unimate Without any fanfare the world s first working robot joined the assembly line at the General Motors plant in Ewing Township in the spring of 1961 It was nothing like the metallic 9 humanoid robots seen in movies and on television in those days in America and Japan 1 An historical aside robotics pioneer George C Devol who invented the prototype of robotic arms has died in the US aged 99 18 August 2011 The American inventor came up with the concept of Universal Automation which led to Unimate the first industrial robot This was a mechanical arm which was programmable allowing it to repeat tasks like grasping and lifting The first Unimate prototypes were controlled by vacuum tubes Transistors were used later as they became available A rotating drum memory system with data parity controls was invented for the Unimate The Unimate arm was adopted by General Motors in 1961 followed by other auto makers Chrysler and Ford It was first used to lift and stack die cast metal parts from moulds and its role then expanded to other duties like welding and painting The rest as they say is industrial robotics h
26. have been in the precision soeed and strength of robots Learning and artificial intelligence algorithms have probably been the biggest disappointments dont think we will see robots even remotely approaching human intelligence by 2050 15 A decidedly opposing viewpoint compared to the Hans Moravec theoretical prediction for Universal Robots References 1 Robotics an Introduction Delmar Publishing Inc 2 ed 1988 Douglas R Malcolm Jr http Awww robotmatrix org pages 2 Accessed Dec 3 2012 caption for YouTube video Uploaded by idels1 no contact info on Apr 30 2011 http Awww YouTube com watch v J3I5X3gYHPo 3 http www nationaldefensemagazine org archive 201 1 August Pages Army CarMakersPushAheadWithDriverlessVehicleResearch aspx 7 Accessed Dec 3 2012 Robotic surgery http biomed brown edu Courses Bl108 Bl108_ 2005 Groups 04 4 Accessed Dec 3 http Awww robotmatrix org ParallelRobotic htm 5 Accessed Dec 3 http www robotmatrix org RobotConfiguration htm 6 Accessed Dec 3 2012 http www robotmatrix org RoboticSpecification htm 8 Robotics an Introduction Delmar Publishing Inc 2 ed 1988 p 189 Douglas R Malcolm Jr http www robotmatrix org 9 Accessed Dec 3 2012 http Awww robotmatrix org RobotApplicationBylndustrial htm 10 Accessed Dec 3 2012 http www rethinkrobotics com 11 Accessed Dec 3 2012 Industrial Robots http Awww learnaboutrobots co
27. in the robots links and joints and motor demands etc However our robot does have size dimensions and motion range limitations which comprise the functional kinematic analysis Traditional kinematic analysis would require identifying every point reachable by the end effector relative to the base by some 3 dimensional coordinate system such as polar cylindrical or spherical systems Gyro sensors are essentially evaluating three axes of angular rotation of a spherical coordinate system By using the human operator s visual feedback control our design doesn t have to precisely mathematically identify the 63 exact location of the end effector constantly the way a robot arm on a production manufacturing assembly line would However the gyro sensor data has to be accurately interpreted for the proper scaled motion of the robot arm following the human operator s arm motion Feedback sensors may have to be applied to the robot arms joints for better control of the slave motion robot arm The technical specifications of the OWI 535 Robot Arm Edge kinematics are 1 e wrist to end effector range of 120 degrees vertical rotation only no perpendicular rotation which is a possibility with a hardware upgrade to a lynx arm e elbow to wrist range of nearly 300 degrees also vertical only e base shoulder to elbow rotation of nearly 180 degrees vertically and almost 270 degrees of base horizontal rotation horizontal reach of 12 inches verti
28. of the robotic hand had force sensors on the end of them These sensors were connected to the control loop for the servo on the glove In the case that the robot hand was grabbing something the force sensors would generate a voltage reaching a 5V max This would negate the update signals to the servo on the glove causing it to prevent any more motion from the user This restraint on motion would allow the user to feel the object that was in the robot s grip Wee q eae Figure 3 1 2 Haptic Feedback Robot Hand 3 1 3 Other Projects Many other projects were found while researching examples but most of these projects were either commercial products or projects being developed by universities Since commercial products have monetization as a goal the 16 technical details were unavailable or protected by patents as were most of the university projects Even though these projects contained good and relevant ideas because the technical details were not available they could not be studied in enough detail to provide insight in this group s project 3 1 4 Similar Robot Arm Projects A search of the internet found some similar projects on YouTube and other websites A couple of pictures of motion tracking robot arms are shown below that combine the shoulder and elbow swivel horizontal vertical angular motion in one base unit with rotating wrist and pincers Comments notice they are both wired so it might be a good idea to add
29. reduces the number of motors the control board can handle This architecture shows that a motor driver can be used on the same pcb board 53 as the microcontroller with no extra power source to drive the motors The downside to this is that the motor driver on the Baby Orangutan can only power 2 motors making additional drivers necessary for more motors Another drawback to the Baby Orangutan is that it requires an exterior component in order to program the microcontroller The schematic for the Baby Orangutan is in the figure below voc Avec BA Li 10uH c7 0 1 uF LP2981IM5 5 0 Bhai seal baie sd O1uF lt 1 D2 et Green R3 TRIMPOT EFE 3303 E Pololu Baby Orangutan B 48 B 168 pinout top view en Schematic diagram 19 May 2008 Figure 4 3 2 Pololu Baby Orangutan schematic Another control board studied for this project was a previous senior design project from Fall 2009 shown in figure 4 3 3 The project dubbed Luke s Hand also involved controlling motors based on input from sensors This control board was particularly useful in that it did not have a separate motor controller but rather a separate power circuit for the motors with on and off signals sent from the microcontroller This architecture uses more pins on the microcontroller since 1 pin per motor is required but saves space as a separate motor driver is not required The downside of this control board was the microcontroller chosen The
30. robot s controller Another question is raised from this information will our robot arm need to be adjusted or even reprogrammed when the human operator is changed from one person to another Presumably we will use a hinged mechanical template over the operator s arm that will be transferable from one user to another as observed in the YouTube screen captures in section 3 1 Similar Projects In fact we used Velcro straps to mount the sensors see section 10 2 System Construction An interesting observation about industrial robots the cost of implementing an industrial robot can be three to four times the cost of the robot itself because of the cost of the tools the robot uses combined with the cost of programming the robot 11 This explains the motivation to create independently contained robots with direct application program ability by non technical people and versatility for multiple work environment uses and re uses Baxter is arguably an evolution of a Flexible Robotic Manufacturing System that traditionally required machine and routing change ability such that any applications that involve high mix high volume assembly require flexible automation Manufacturers need the ability to run different products on the same line That s much more difficult to do with hard automation 12 To close this section an observation from an industry professional What are some of the advancements in robotics 21 The biggest advancements
31. schedule to work as 126 a team member and to communicate in writing Group 10 achieved all of these with the exception of meet a schedule An over confident design change decision to jump directly to 6 1arm assembly and coding instead of progressing from 4 1 through 5 1 to 6 1 arm assemblages and coding combined with a vendor delivery delay of three weeks servos severely diminished both the final arm performance and the system evaluation Acquiring the 6 rotating joint the elbow delayed the ordering of the servos by virtually a month The combined delays put our project start date at virtually March 23 Although our final sensor boards were not available until the day before March 22 a lot of system evaluation could have been done with the arm configurations run directly from the mcu without any sensors and with the one prototype 3 axis gyro sensor board Realistically the engineering system evaluation begins at the end of the build phase Projects should be targeted required to be completely built software at least minimally working by the middle of March Appendices Appendix A Copyrights amp Permissions Figure 4 3 2 Hello Taylor You are welcome to use the schematic of that product in your report as long as you give us credit Please let me know if you have any additional questions Sincerely Jonathan Kosh 702 262 6648 www pololu com Pololu Corporation 920 Pilot Rd 127 Las Vegas NV 89119
32. send data to the motors 4 e Have enough memory to store the control software and data gathered from the sensors e Be fast enough to only have a slight delay between the operator s motions and the robot s motions 5 Specifications for the project prototype include the robot arm s dynamic range see 5 1 1 Robot Arm Kinematics showing mechanical views of the OWI arm SPECIFICATIONS Assembled Size Qin x 6 3in x 15in Unit Weight 658g Battery D size x4 Definitive response times for the robot arm s motion were not determined because of severe time constraints created by starting the project software coding almost two months late March 23 Nominally motion tracking of the human operator s arm should follow within tenths of a second or better as has been observed in a YouTube video Haptic robotic arm 1 see Fig 3 1 3 in section SIMILAR PROJECTS Our system does not respond this fast however we are driving six rotating links and not two as in Fig 3 1 3 The initial plastic mechanical arm with small dc motors was able to track steady rotation of the gyro sensor very effectively in time and proportional motion response through two degrees of freedom of the base horizontal rotation and shoulder link vertical elevation Only one 3 axis gyro STM L3G4200D was acquired for the prototype since 6 axis InvenSense mpu 6050 motion sensors were chosen for the final metal arm no SPI interface to connect two more sensors to the prototy
33. servo motors DC motors operate continuously when power is applied nominally a forward or 69 clockwise rotation if a positive voltage is applied across the motor and a reverse or counterclockwise motion if a negative voltage is applied across the motor Stepper motors rotate a few degrees when power is applied To generate continuous motion with a stepper motor requires pulsing the power to the motor Servo motors would be the first upgrade choice and are dc motors with position feedback providing accurate continuous angle rotations Motor performance specifications include operating voltage current draw torque and speed The current motors are small dc motors requiring 3 volts and drawing 0 6 to 1 2 amps when running they are low torque and high speed and have to be geared connected to a gearbox to be useful on the robot arm as they rotate at a few thousands of revolutions per minute or dozens of revolutions per second Upgrading to servo motors means a robot arm can be used without external to the motor gearboxes which should facilitate faster response time of the tracking motion of the slave robot arm Servo motors are enclosed in a plastic box that includes the servo a gearbox a feedback device probably a potentiometer plus drive and control circuitry 1 The figure below shows our current motor on the left dc motor and our probable future upgrade on the far right Servo motor dc motor stepper servo Fig 5 2 2 1
34. the accelerometers output vector magnitude at a maximum of 1g which can be an indicator of the correctness of the compensation values 5 4 Wireless Subsystems 5 4 1 Bluetooth vs Wifi 77 When you mention wireless communication two options come to mind Bluetooth and wifi Both have similar network programming that can be split into several components as shown the diagram below Choosing a Figuring out device to communicate communicate with with it Making an Accepting an outgoing incoming connection connection Sending and receiving data Figure 5 4 1 1 Diagram showing how Bluetooth and Wifi connect with another network 5 Though they serve the same general purpose both are quite different in their standards of operation Bluetooth is most useful when multiple devices two or more that are close together transfer information between one another Examples consist of telephones printers modems and headsets Wifi on the other hand allows for faster connection and works best for operating full scale networks Overall wifi would seem to have the advantage over Bluetooth as it has better security more bandwidth greater range and higher bit rate 1 The disadvantages though consist of a greater cost more complex ease of use higher power consumption and slower speed if multiple devices are connected to the same network Bluetooth has the ability to have many devices sending and receiving data at the same time and still mai
35. to the wrist link distanced remote operation etc The overall goal is fast accurate and stable motion tracking of the human operator s arm by the robot arm An exact response time is difficult to specify at this time because of the designers unfamiliarity with the specific hardware devices and software requirements however research indicates that quite fast and accurate proportional motion response is attainable Because of the slow response limitations of our initial plastic mechanical arm with small dc motors we will target a 1 second response time of the robot arm following the human operator s arm and then try to cut that to a tenth of a second or better when switching to the metal robot arm with servo motors The grasp and lift capability of the robot arm is a predefined feature of the mechanical robot arm employed with our electronics A lift capability of close to 50 grams has been decided on for this project While upgrades to the robot s motors could be applied to increase this factor a robot arm already capable of lifting a payload close to the goal would be preferred 2 2 Project Requirements and Specifications The robot arm is going to mirror the motions of the motions made by the user s arm and therefore must meet certain requirements These requirements are to ensure that the whole project meets as many of the goals set as possible The end result should be an easy to use interface that produces fast accurate movement f
36. 0 Billion dollars of the U S Gross Domestic Product and significantly reduce the amount of out sourced manufacturing 2 Additionally The industrial robotics market is expected to experience huge growth in the near future with a CAGR Compound Annual Growth Rate of 5 5 It is further forecast that with this CAGR the global industrial robotics market shall be worth USD 32 9 billion by 2017 it is estimated that the worldwide industrial robotics market will have a volume of approximately 1 500 000 units by 2017 whereas the estimated volume in 2011 is 1 100 000 units worldwide 3 For the future it appears the quest is reducing the initial installation costs of switching labor to robots while at the same time increasing the speed at which the robots contribute to productivity of ever smaller sized business with a greater variety of work capabilities Cheaper and more versatile are the successful concepts of future robotics References 1 Accessed Dec 5 2012 Consumer Robot Sales to Surpass 15B by 2015 http www roboticsbusinessreview com article consumer_robot_sales_to_surpas s 15b by 2015 2 Accessed Dec 5 2012 Top 10 Best Jobs for Robots 2012 http www roboticsbusinessreview com article top_10 best_jobs for_robots 20 12 3 Accessed Dec 5 2012 Industrial Robotics Market Global Industry Size Market Share Trends Analysis And Forecasts 2012 2018 http beforeitsnews com science and techn
37. 2C or SPI to communicate 2 pins 12C or 4 pins SPI are required to interface 133 Adafruit invests time and resources providing this open source code please support Adafruit and open source hardware by purchasing products from Adafruit Check out the links above for our tutorials and wiring diagrams Written by Kevin Townsend for Adafruit Industries BSD license all text above must be included in any redistribution To download click the DOWNLOADS button in the top right corner rename the uncompressed folder Adafruit_L8GD20 Check that the Adafruit_L3GD20 folder contains Adafruit_L3GD20 cpp and Adafruit_L8GD20 h Place the Adafruit_L8GD20 library folder your Arduinosketchfolder libraries folder You may need to create the libraries subfolder if its your first library Restart the IDE 134
38. 5 2 1992 R1999 UL4u4YPAeAo 8 2 Motor Testing The motors selected for the metal robotic arm are servo motors They respond to the pulse width of the input signal to determine position Because the purpose of this project is motion mirroring the sensitivity of the servos is of great importance In terms of servo specifications we would like the servos to have a deadband period as small as possible This will be tested by recording the input signal with an oscilloscope and recording the output shafts angle relative to a base line to determine the minimum change in the signals duty cycle in order to produce a change in the output shafts angle This minimum change in output shaft angle will determine the minimum arc length created by the arm During the testing of the motors there will be a measurement of the power consumed by the motors under various loads to see the efficiency of the motors This is done by measuring the current drawn by the motors and multiplying it by the voltage supplied to the motors There will also be testing done to see the effect the input voltage has on the position of the output shaft for the same duty cycle period This will be of great importance if the robotic arm is being ran off of batteries This will enable the group to determine the maximum run time for the robotic arm based on the specification of the batteries and the effect the input voltage has on assumed output shaft angle 109 8 3 Sensor Testing In
39. 7 10 8 V DC motor sia M DC motor Minimal wiring diagram for connecting a microcontroller to a DRV3333 dual motor driver carrier J jlo nuovo w Fig 5 2 3 A pinout of the DRV8833 1 67 GND To GND VMM 7 J VIN BIN1 Li J BOUT1 BIN2 LF J BOUT2 AIN2 Li J AOUT2 AIN1 Li J AOUT1 nSLEEP Li J AISEN nFAULT L _2 BISEN Fig 5 2 4 Pinout descriptions PIN VIN VMM AOUT1 AOQUT2 BOUT1 BOUT2 BINA BIN2 SLEEP nFAULT AISEN Default State LOW LOW LOW LOW HIGH FLOAT Description 2 7 10 8 V motor power supply connection Operation with VIN below 5 V slightly reduces the maximum current output This pin gives access to the motor power supply after the reverse voltage protection MOSFET see the board schematic below It can be used to supply reverse protected power to other components in the system It is generally intended as an output but it can also be used to supply board power Ground connection points for the motor power supply and control ground reference The control source and the motor driver must share a common ground The motor A half bridge 1 output The motor A half bridge 2 output The motor B half bridge 1 output The motor B half bridge 2 output A logic input control for motor channel A PWM can be applied to this pin A logic input control for motor channel A PWM can be applied to this pin A logic input control for motor channel B PWM can be applied t
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41. After the serial signal is directed to the other microcontroller that controls the servomotors of the robot this second microcontroller decodes the serial signal using the other Bluetooth Module With the interpretation of this data the servomotors of the robotic arm will move following the commands given by the user from any point provided within the scope range of Bluetooth modules 8 5 Controller Testing The confirmation that the control board is functioning at an expected level was an important step nearing the completion of the build phase of the project To ensure that the control board functioned as required by the specifications different tests were performed to demonstrate that the various components performed as required The procedures to test these components are described in the following paragraphs The first step in making sure the control board was functioning properly was to ensure that the microcontroller was being properly programmed Sample pulse signals were sent to pins on the microcontroller to test the basic hardware integrity of the custom built microcontroller unit The Atmel AVR IDE was used with a programmer interface to program the ATxmega1i28A4U microcontroller on the test board A second test was to ensure that the microcontroller was properly controlling the motors on the robot In order to do this the microcontroller was uploaded with a 115 program that sent signals to the motors of the robot The program w
42. Conclusion do anything different Appendices 134 Appendix A Copyright Permissions Appendix B Datasheets Appendix C Software Chapter 1 Executive Summary The purpose of the senior design project from the course description of objectives is To provide students a complete design experience including the necessity to set design goals and objectives integrate knowledge exercise engineering judgment plan to meet a budget and schedule to work as a team member and to communicate in writing To accomplish these objectives our group Helping Hand designed a tele operated master slave robot arm which motion tracks a human operator s arm motion including open close hand tracking by the end effector The project is exclusively focused on the electronics and software to control an electrically operated robotic arm Stock mechanical robot arms and servo motors were utilized as needed to accomplish the project 1 Why study the human operated robot arm The future of robotics in manufacturing and assembly is increased flexibility both in mechanical performance and ubiquitous integration with human workers The future of robotics is greater dexterity easier and quicker program ability and safe operation with human co workers Building a tele operated master slave robot arm driven by sensors worn on a human arm is investigating future possibilities and general performance considerations of advanced robotics See Section 3 0 Introduction Uni
43. Hand will use a closed loop feedback system in a master slave arrangement between a human operator s arm motion and the robot arm s motion mirroring response tracking from motion and force sensors on the human operator s arms and hand To learn about robotics particularly with regard to how our Electrical and Computer Engineering undergraduate education relates to the working robotic world is also a significant factor in our choice of senior design project This is a very technologically challenging project the other similar projects reviewed while researching this project have fewer degrees of freedom and less overall difficulty The number one project goal is to create a motion tracking system of a custom or stock robot arm that can proportionally replicate a human operator s arm motion The initial prototype will be wired directly between sensors on the operator s arm and the controller on the Helping Hand The Helping Hand itself is operated by control signals from the controller to motors on the robot arm controlling direction and magnitude of subsequent motion The whole interface should be relatively easy to use and should require little assistance to set up and begin use Depending on how fast we can implement the basic function of the Helping Hand in the second term of senior design project we can add features such as wireless signal transmission from the operator s arm sensors to the controller and more complex motions add rotation
44. Helping Hand Senior Design Final Documentation Group 10 Spring 2013 Kurt Graf Taylor Jones Matt Carlson Eric Donley 4 29 2013 Table of Contents Chapter 1 Executive Summary Chapter 2 Project Description 2 1 2 2 Chapter 3 Research Related to Project Definition 3 0 3 1 3 2 3 3 Chapter 4 Research Related to Components 4 1 4 2 4 3 Motivation and Goals Project Requirements and Specifications Introduction Similar Projects General Research on Robotics Robot Business Relevant Technologies Possible Components Example Architectures and Diagrams Chapter 5 Design Details 5 1 5 2 5 3 5 4 Design Architecture and Related Diagrams Motor Subsystems Sensor Subsystems Wireless Subsystems 11 38 59 5 5 Controller Subsystems Chapter 6 Design Summary 93 Chapter 7 Build Plan 97 7 1 Parts Acquisition for Prototype 7 2 Prototyping 7 3 Hardware Assembly 7 4 Software Integration Chapter 8 Project Testing 104 8 0 Testing checklist 8 1 Testing Environment 8 2 Motor Testing 8 3 Sensor Testing 8 4 Wireless Testing 8 5 Controller Testing Chapter 9 Administrative Content 124 9 1 Milestones 9 2 Budget and Financing 9 3 Looking Toward EEL4915 and Back Chapter 10 EEL4915 Design Implementation 126 10 1 System Final Design Summary 10 2 System Construction 10 3 System Performance 10 4 System Budget 10 5 Project Review Successes and Errors 10 6 Project
45. Micro does not have access to many libraries that could help speed the development process PICAXE Programming Editor does have a unique feature in that it allows users to develop a program for their microcontroller using a flowchart This feature allows users to create a flowchart that dictates a 46 sequence of actions that should be taken by the microcontroller and then converts it to the BASIC code that would cause the desired effects This tool might be useful in speeding the learning the BASIC language as users could create flowchart and then see what the code looks like to help the transition to just using code Another microprocessor considered was the ATxmega128A4U made by Atmel This microcontroller has 34 I O pins 128 KB of memory 8 KB of SRAM and 2 KB of EEPROM The 34 I O pins would be more than enough to handle the components for this project The 128 KB of memory is enough to store the control algorithm the 8 KB of SRAM would be more than enough to store the temporary values of the various sensors and the 2K of EEPROM is plenty to store any values that would need to be permanent such as a default position for the robot The 12 A D converter pins is enough to handle all the sensor data from both the user and robot Atmel makes many tools for its products accessible such as it s free IDE Atmel Studio 6 This IDE allows users to program their microcontroller in C C or assembly language unlike PICAXE or Basic Micro The IDE is a
46. O 9283 sets out a method whereby both accuracy and repeatability can be measured Typically a robot is sent to a taught position a number of times and the error is measured at each return to the position after visiting 4 other positions Repeatability is then quantified using the standard deviation of those samples in all three dimensions 1 Although the industrial website www strobotics com repeat htm references Wiki directly tried the original source listed on Wiki for the definitions of accuracy and precision and found the nternational vocabulary of metrology Basic and general concepts and associated terms 2 2 13 3 5 103 measurement accuracy accuracy of measurement accuracy closeness of agreement between a measured quantity value and a true quantity value of a measurand NOTE 1 The concept measurement accuracy is not a quantity and is not given a numerical quantity value A measurement is said to be more accurate when it offers a smaller measurement error NOTE 2 The term measurement accuracy should not be used for measurement trueness and the term measurement precision should not be used for measurement accuracy which however is related to both these concepts NOTE 3 Measurement accuracy is sometimes understood as closeness of agreement between measured quantity values that are being attributed to the measurand 2 15 measurement precision precision closeness of agreement between ind
47. S WEBSITE YOU HEREBY ACKNOWLEDGE THAT ANY USE OF THE WEBSITE AND RELIANCE UPON ANY MATERIALS SHALL BE AT YOUR SOLE RISK AND THAT COMPANY 129 SHALL NOT BE LIABLE FOR ANY LOSS OF DATA LOST PROFITS OR ANY OTHER DAMAGES OR LOSSES RESULTING FROM SUCH USE Copyrights http Awww learnaboutrobots com copyright htm If you find anything on this site that you feel infringes on a copyright please let me know and will do my best to rectify the situation You may not copy or redistribute any of the digital images on this site without express written permission from the copyright holders Please give credit if you use more than a line or two of text from this site Rich Hooper Appendix B Datasheets Information reference for 4915 from section 4 2 possible components Accelerometer amp Gyro Tutorial http www instructables com id Accelerometer Gyro Tutorial step1 The Accelerometer Appendix C Software Sample code for section 8 1 Here is the test code used to call the gyroscope class include gyroscope h ardadv sensors gyroscope Gyroscope gyroscope void setup Serial begin 9600 130 Serial flush typedef ardadv sensors gyroscope Gyroscope Gyroscope gyroscope setup Gyroscope INTA 7 Gyroscope INTB 6 Gyroscope CS 10 void loop gyroscope update const unsigned long t millis Serial print t Serial print Serial print gyroscope x DEC Serial print
48. This flexibility allows this motor controller to be integrated directly into the control circuit for the robot and stay within the specifications for the project The lack of monitoring of the motors means that there is the possibility of damaging the motors if care isn t taken while building and testing the circuit A final motor controller looked at was the 8 channel servo controller from Cytron This motor controller allows for the control of 8 servo motors simultaneously It also allows the monitoring of each servo s position and is able to deactivate or active them Another feature of the motor controller is that it can set an initial starting position of any channel the next time it starts up This feature would be useful for resetting the robot to a default position The Cytron control board can also be chained together with other motor controllers to provide control over even more motors if required The controller is able to communicate with a computer through the use of a USB to serial converter or with a microcontroller with an UART interface This would allow the motor controller to interface directly with the rest of the control board for this project and stay in line with the specifications A summary of the motor controllers considered for this project is presented in table 4 2 2 The table includes how many motors the controller can control what it Can communicate through what it monitors and their price Name Motors
49. USA Figure 5 4 3 2 Hi Matthew yes you have permission to use that image Regards John Main The Only Microcontroller C Programming Course Showing You How To Make Your Own C Projects http www best microcontroller projects com c start Get the Microcontroller ezine for C programming tips projects and more Visit http Awww best microcontroller projects com ezine Fig 3 1 4 info technophilia co in contact info no response as of 12 5 2012 I am a student in electrical engineering at Univ Central Florida in Orlando FI USA would like to have permission to use a screen capture of your demo on YouTube http www YouTube com watch v vqbNoALYVd4 amp feature related for a senior design report on robot arms The screen capture is of the black and yellow arm following the human operators motions Kurt Graf candidate B S EE UCF Sent 11 29 2012 Note from section 3 2 Permissions Disclaimers refers section 3 2 128 Disclaimer from website http www robotmatrix org Disclaimer htm for sources 4 5 6 While we strive to provide accurate and timely information there may be inadvertent technical and or factual inaccuracies and typographical errors For which we apologize No Warranty No Liability Indemnification THE WEBSITE AND THE MATERIALS ARE PROVIDED BY COMPANY ON AN AS IS BASIS AND AS AVAILABLE WITHOUT ANY WARRANTY OR REPRESENTATION OF ANY KIND WHETHER EXPRESS OR IMPLIED COMPANY EXPRESSLY DISCL
50. al Robotics the robot industry has become mature since 2005 find that claim somewhat precocious it seems to me that the robot industry is just really beginning in the 20 teens particularly regarding humanoid work capabilities The first web search for robot business found the Robotics Business Review website 1 A surprisingly robust and actively populated website that features current news and trends in robots and high technology considerations like the increasing legal blurring between people s identity and people s property because of things like cyborg robotics The title of an article perhaps best 29 explains the conflict The Cyborg Agenda Blurring Body Boundaries Where will the law draw the line between your intelligent prosthetic and you 2 The website advertises itself as the 1 resource reporting and analyzing up to the minute business developments technology developments and financial transactions across the fast changing landscape of global robotics Includes full access to the RBR50 complete profiles and analysis on the Top 50 compelling robotics companies worldwide for 995 charter rate 1 A very interesting article was found that mentioned Baxter and the emergent concern about Baxter in the workplace Baxter in the workplace instead of you Baxter and its growing band of next generation co worker robots Technology in the form of robots is on the march checking off likely candidate jobs for work tr
51. alues of the sensors to check against incoming data This microcontroller also 11 A D converter channels which would be enough to handle all the data from the sensors and allow simpler board design as it would not require an external converter Basic Micro products are provided with a free IDE called Basic Micro Studio that allows the programming of their products in BASIC The IDE comes with an extensive library with example programs for many of their products as well as Lynxmotion robots These libraries would be a great advantage but the use of BASIC requires learning of the language and might slow down the development of the project A second microcontroller considered for this project was the PICAXE 20X2 made by PICAXE This microcontroller has 18 I O pins 4 KB of memory and 256 bytes of RAM This microcontroller has enough I O pins to handle all of the components it will interacting with as well as enough RAM to store the temporary values of the sensors The memory space might be an issue as it could be too small to hold the control algorithm which would then require some form of external storage which would complicate the board design The 11 A D converter pins that this microcontroller has will be sufficient for conversion the sensor data will require and would allow simpler board design PICAXE products are also provided with a free IDE called PICAXE Programming Editor This IDE uses BASIC to program the microcontrollers but unlike Basic
52. and pass them along to the motors Having the listed requirements from the introduction would allow the motor controller to completely control the robot arm from a single unit A motor controller designed for servo motors would be best as most robotic arms use servos for their control Being able to control five motors at once would mean only one controller is needed and would decrease the space needed for the completed control board One motor controller looked at was the Phidget Advanced Servo 8 Motor controller This controller is able to control up to 8 servo motors simultaneously The controller allows the user to change the position velocity and acceleration of all the motors connected The controller also monitors the power consumption of each servo and protects the motors from overvoltage The Phidget motor controller only connects to a USB port requiring control from a microcontroller to come through a computer This is a conflict with the project specifications as it should work as an embedded system without any assistance from a computer A second motor controller researched was the 8 Servo PC Controller from ServoCity This controller is also able to control up to 8 servo motors simultaneously This motor controller allows you to control position velocity and acceleration but does not monitor power consumption of the servos The motor controller is connectable to either a USB connection or a signal wire from a 48 microcontroller
53. ansformation and then showing up at work sites to show business owners how well they can do the job The rule of thumb for switching out a human for a robot is twice the human s annual salary Since new generation robots such as Baxter and its kind others are soon to arrive from Universal Robotics ABB FANUC and Yaskawa run about 20K each the business decision is easy enough to see It s said that 500B of the US GDP s total output of 15T 2011 could in the near future be thrown on the backs of robots and that these machines at critical mass could make offshoring of US manufacturing a distant memory real fast 3 The article continues on to specify which industry workers are most vulnerable to replacement by robotics The jobs most at risk So who exactly are the neighbors friends and relatives closest in jeopardy of getting axed by these disruptors During 2012 the following jobs have seen significant robot tryouts nearly all with excellent results Butchers dairy farmers furniture makers kitchen helpers lumberjacks machinists miners parts packers and pharmacists 3 A related article explains big robotic intentions within the mining industry The robot trials were part of a movement toward a future of autonomous mining in which Rio Tinto is investing 3 6 billion the ultimate goal of which the company calls the Mine of the Future Starting in 2008 and concluding in February of 2012 a vanguard of nine robots an exc
54. arm sensor is done to adjust their values for being affected by motion meant for a higher sensor The data is then converted to a percentage of its max value and multiplied by the relevant motor s duty range divided by 2 and added to its center duty 97 Chapter 8 Project Testing 8 0 Testing checklist Prototype Testing Procedure Hardware HM device Test Pass Fail Comments OWI Robot Basic mechanical operation with Operates properly but response time Arm manual control box X looks slow Gyro Sending data from simple test Gyro is very sensitive and requires sensor motion to Arduino successfully software filter to prevent jitter X Pressure Sending data from test to Arduino FSR resistance drops very rapidly sensor successfully from M ohms to low k ohms X Arduino Functioning properly Very easy to use No programmer X device required just usb cable Motor Sending drive commands to Works well with Arduino and dc Driver motors successfully motors Not needed for servo X motors Prototype Testing Procedure Software S W function Test Pass Fail Comments Arduino systems check Computing and communications systems No problems integrity good X Programming Gyro in Data communication effective and No problems the Arduino processed accurately for motion analysis X Programming Motor Proper drive commands sent to the No problems Driver in the Arduino motor s
55. avator track dozer wheel dozer motor grader and five 930E AT haul trucks all supplied by Komatsu Ltd underwent extensive field testing at West Angelas The Pilbara robot trials were a real world success The most watched machine was the autonomous AT version of the Komatsu 930E the best selling off road dump truck in the world and now soon to be strategic hauling tool of choice for the Pilbara s millions of tons of China bound iron ore Rio Tinto is pushing forward with a full scale autonomous mine implementation including 442 million for autonomous ore hauling trains over its rail network 4 30 Similar to the DUCSS project of UCF 2006 see 3 1 Similar Projects under DARPA coordination Rio Tinto has worked with Australian academia Australian Centre for Field Robotics ACFR at the University of Sydney early on in 2007 establishing the Centre for Mine Automation to which Rio Tinto committed an initial 21m of funding According to the University of Sydney its mission at the Rio Tinto Centre for Mine Automation RTCMA is to develop and implement the vision of a fully autonomous remotely operated mine both open pit and underground 5 Needless to say there were related articles for each of the job fields of vulnerability to robotic replacement detailing similar robotic developments All of which generates the section Future Of Robotics However the current topic is what exactly are the business numbers about robotics Th
56. based on gyro input X Programming Pressure Proper signals sent to the Arduino for FSR only sensor in the Arduino sample test pressures X checked Robot Arm motion Is gyro data for base rotation properly No problems 1 base rotation processed into the robot arm motion X 2 link 1 shoulder to Is gyro data for link 1 vertical rotation elbow vertical rotation properly processed into the robot arm X No problems motion 3 link 2 elbow to wrist Is gyro data for link 2 vertical rotation Not done vertical rotation properly processed into the robot arm different sensors motion for metal arm 4 link 3 wrist vertical Is gyro data for link 3 vertical rotation Not done rotation properly processed into the robot arm different sensors motion for metal arm 5 link 4 end effector Ils pressure sensor data for link 4 lateral open and close translations properly processed into the Not done robot arm motion 98 Since different sensors were chosen to use on the metal arm than the prototype the prototype development was not pursued beyond the shoulder base horizontal and vertical rotations one 3 axis gyro Metal Arm Build and Test Flowchart see next page 99 Design Eel4914 Build plastic arm prototype Acquire electronic parts Sensors to mcu to motors Acquire metal arm and 7 weeks later servos Build metal 4 1 arm and test with proto mcu and new s w Acquire gyros and m
57. be within 0 1mm Accuracy and repeatability are different measures Repeatability is usually the most important criterion for a robot ISO 9283 sets out a method whereby both accuracy and repeatability can be measured Typically a robot is sent to a taught position a number of times and the error is measured at each return to the position after visiting 4 other positions Repeatability is then quantified using the standard deviation of those samples in all three dimensions am not certain at the present how to interpret and analyze our proportional master slave motion application compared to the traditional absolute position of the robot is measured and compared to the commanded position robot motion analysis Also from Wikipedia the best and simplest also the only graphic have ever seen to explain accuracy and precision 3 Reference value Probability Accuracy density _ __ Value Precision Fig 8 1 1 Note precision is repeatability and accuracy is reference to some standard value Some research was found on the internet regarding gyroscope calibration 4 106 The first thing did was turn on the gyroscope and let it sit stationary on the table This estimates the zero settings Here is an example of the output The mean of response is lt 52 5054 17 3098 12 8859 gt This is used to correct the up front bias in the voltage settings simply subtract this value as it is read to remove the bias
58. bject Of these the most widely used standard is RS 232 which stands for Recommended Standard number 232 Primary communication is accomplished using three pins the Transmit Data pin the Receive Data pin and the Ground pin 3 81 Serial interface RS232 MAX2320P Figure 5 4 3 2 shows a serial connection to from the PC that lets RS232 work between it and a microcontroller 8 Two basic types of serial communications are synchronous and asynchronous communications 5 4 3 2 1 RS 232 The RS232 standard describes a communication method where information is sent bit by bit on a physical channel The information must be broken up in data words On PC s a length of 7 and 8 bits are most common but 5 and 6 are also available For proper transfer additional bits are added for synchronization and error checking purposes as described in the previous section It is important that the transmitter and receiver use the same number of bits if not the data word may be misinterpreted or not recognized at all With RS232 the line voltage level can have two states The on state is also known as mark the off state as space No other line states are possible When the line is idle it is kept in the mark state Start bit RS232 defines an asynchronous type of communication This means that sending of a data word can start on each moment If starting at each moment is possible this can cause issues for the receiver in knowing which bit is
59. bot and the work environment and to store and execute programs which operate the robot 19 As an interesting aside regarding the future of Baxters evolution robotic research scientist Hans Moravec predicts a four stage progress to universal robotics human intelligence equivalent robots 20 e Year 2010 Processing power 3 000 MIPS Intelligence equivalent Lizard e Year 2020 Processing power 100 000 MIPS Intelligence equivalent Mouse e Year 2030 Processing power 3 000 000 MIPS Intelligence equivalent Monkey e Year 2040 Processing power 100 000 000 MIPS Intelligence equivalent Human A research homework paper written for EEE4314 semiconductor devices ll indicates the Moore s Law progression hitting the wall of 3 nm by the early 2020 s The computing horsepower progression could be a problem Scaling transistors in 3D might continue Moore s Law for microprocessors Also contrast this prediction with the robot industrial expert quote at the close of this section Computer programming is done inside the processing power of the robot and generally involves control structures data types signal processing algorithms and hardware control algorithms 21 Our project is basically two parts design and build the printed circuit board controller and then process the sensor data from the human operator s arm to drive the robot arm motors Power Sources The plastic OWI robot arm uses 4 D cell batteries to drive the dc mot
60. c and build sensor boards and mcu Test sensor boards and mcu 100 NOT OK NOT OK NOT OK NOT OK NOT OK Connect sensors to mcu to metal 4 larm Test metal 4 1 Arm with one sensor board Test metal 4 1 Arm with two sensor boards Test metal 4 1 Arm with three sensor boards Evaluate 4 1 system performance h w and s w Connect sensors to mcu to metal 5 1 arm Test metal 5 1 Arm with one sensor board 101 NOT OK NOT OK NOT OK NOT OK NOT OK NOT OK NOT OK Test metal 5 1 Arm with two sensor boards Test metal 5 1 Arm with three sensor boards Evaluate 5 1 system performance h w and s w Connect sensors to mcu to metal 6 1 arm Test metal 6 1 Arm with one sensor board Test metal 6 1 Arm with two sensor boards Test metal 6 1 Arm with three sensor boards 102 Evaluate 6 1 system performance h w and s w Final system performance 4915 report The severe loss of time due to a design change additional component acquisition elbow rotation unit delay and another component delivery servos delay resulted in only 9 of 22 eel4915 build and test tasks being completed 8 1 Testing Environment TESTING ROBOT CALIBRATION Trying to write a section on Robot Testing immediately encounters ISO International Standards Organizations 9283 for 162 5 and ANSI RIA R15 05 2 1992 for 67 6 Subsequent hunting the internet gathers some information IS
61. cal reach of 15 inches lifting capacity of 100 grams Dimensions 9 L x 6 3 W x 15 H Weight 658 grams Top view 64 Side view and orthographic projection References 1 Accessed Nov 28 2012 OWI Robot Arm Edge Assembly and Instruction Manual pdf http Awww robotshop com pdf OW1I 535_Manual pdf 5 2 Motor Subsystems 5 2 1 HOW MOTOR DRIVERS WORK A motor driver has its own power supply to take a control signal from the processing control and turn the motors on the robot arm on or off and clockwise or counterclockwise additionally soeed can also be controlled The basic circuit of a motor driver is the H bridge circuit that functions by alternating the applied voltage to a dc motor from plus to minus voltage by flipping one set of two switches or another set of two switches 65 Fig 5 2 1 If switches S1 and S4 are closed a positive voltage is applied across the motor If switches S2 and S3 are closed a negative voltage is applied across the dc motor and the direction of the motor is reversed The initial hardware circuit design is currently looking like Power supply HUMAN ARM Force sensor ROBOT ARM Gyo Robot Arm sensor gt Arduino Motor driver Dc motors 5 Micro boar gt Control ii m ontroller gt possibly feedback gt Sensors on the arm linkages processing a sensor Gyro i l sensor i H Feedback from arm motion Fig 5 2 2 The initial moto
62. ccelerometer and HMCs883L triple axis magnetometer to give you nine degrees of inertial measurement The outputs of all 1 quantity sensors are processed by an on board ATmega328 and output over a serial interface This enables the 9DOF Razor to be used as 76 in stock images are CC BY NC SA 3 0 a very powerful control mechanism for UAVs autonomous 124 95 price and image stal il tion systems t117 AG ANL nnie Fig 4 2 9 9 40 Hitec is the motors that are currently in the arm but these are digital and some are slightly stronger XQ Power motors are stronger and cheaper but I ve seen some reviews that say they had some issues with them a base Recommended a7 ae a O Hitec ns saashb a 0 7 24 99 shoulder Recommended hsaos_ 343 i XPower xa ssozod_ 3873 0 8 22 28 Hitec hsssosmg s 0 2 69 99 sen recommendea eres mf oaf __ i XPower xa saoisd 208 2 012 19 85 2 wrist Recommended Dume E i XPower xa ssoid as27 012 19 85 ites hs seasmh asr na 39 99 grip Recommended nsa22 56 9 ote ______ sapower pasoosd L O maf _o 29 9 tee hssassho s oa 24 99 Fig 4 2 10 At this time we are not planning on making our robot arm mobile but if we try the inertial measurement sensors are available along with the gyros and accelerometers Initially enough components will be acquired to start a prototype system to beg
63. chitecture however Parallax must use its own programming language called Spin Parallax does provide libraries with example programs tutorials and schematics to help with development however the use of an unfamiliar language might slow down development of the project 47 A summary of the microcontrollers considered for use on the control board of this project is presented below in table 4 2 1 and contains information relevant to this project The table includes the product name number of I O pins the amount of memory how many A D converter channels what languages they can be programmed in and their price obtained from the producer website Name I O pins Memory A D converter Language Price 14k code Basic ATOM 24 24 368 RAM 11 channels BASIC 8 95 256 EEPROM 4k code PICAXE 20X2 18 256 RAM 11 channels BASIC 3 88 128k code Gero ATxmega128A4U 34 8k SRAM 12 channels assernibl 3 00 2k EEPROM y Propeller 40 pin DIP 32 64k RAM ROM 0 channels Spin 7 99 Table 4 2 1 Microcontrollers considered for the project 4 2 2 Motor Controllers The motor controller will be used to monitor the current state of the motors and send directions to the motors The motor controller is needed because motors operate at higher voltages than the low voltages at which microcontrollers operate The motor controller is capable of operating at these higher voltages and can receive directions from the microcontroller
64. d outputs signals to the servo control board 120 Picture s of arm Shoulder Base Bicep Sensor Forearm Sensor Hand Senor Grip Button Grip 1 Velcro straps mounting sensors on operator s arm 121 Power Supply connected to connector board photo Atmel ATxmega128A4U Micro controller Servo and Sensor Connection Board to p s 122 MCU board Schematic photo P61877 10 3 System Performance 123 System operation is best explained by a sequence of photos demonstrating the robot arm operation System in operation lt i Because of severe time constraints created by a seven week delay in starting the build of the system minimal system evaluation was accomplished A qualitative system assessment would say the robot arm had too much jitter and motion was not smooth enough A quantitative analysis would no doubt agree however we ran out of time before being able to do any significant system parameterization The initial response is that filtering the data by software thresholding before sending drive signals to the servo motors would reduce the jitter The next question is how much delay the filtering would introduce into the motion tracking response The first solution would be to use the gyroscope data instead of the accelerometer data only Next the gyroscopic and accelerometer data should be combined for a further enhancement of the motion smoothing
65. design If the motion is linear only the masses travel in the same direction and generate no change in capacitance however if a rotational motion occurs the force couple of the two masses moving in opposite directions generates a motion in the plates of a capacitance sensor and a measurement is made of the change in capacitance The change in capacitance is measured as a change in voltage and processed through an analog to digital converter into the system processing power to determine rate of change of angle Subsequent integration of the rate of rotation yields the actual amount of angular rotation The gyroscopes are designed to measure the rate of rotation around all three axes so one gyro can be used for any rotation measurement yaw pitch or roll The gyroscope output can be expressed as Equation 1 Rt SC x Rm RO 1 Where Rt dps true angular rate Rm LSBs gyroscope measurement RO LSBs zero rate level SC dps LSB sensitivity 51 In order to compensate for turn on to turn on bias instability after the gyroscope is powered on one can collect 50 to 100 samples and then average these samples as the turn on zero rate level RO assuming that the gyroscope is stationary 3 References 1 Accessed Nov 22 2012 http sensorwiki org doku php sensors gyroscope Accessed Nov 18 2012 http clifton mech northwestern edu me381 project done Gyroscope pdf For those not registered with the CCC send
66. dware Most of our work will be in programming the micro controller to properly interpret the sensor data and correctly direct the motors on the robot arm NOTE future reference when building system It is important to remember when you use two power supplies is to install a common ground between the two You can still have individual power you just have to have that common ground without it the 12C protocol will probably fail In my testing noticed that my communication failed each time unplugged either of my USB cables from the Arduino finally figured out that if put that common ground in there wont lose communication when I disconnect from the PC make sure you have a minimum of a 1K pull up resistor on each line pulling it to 5 volts personally used 1 5K for all my testing and in my current robot setup 2 1 UM10204 pdf I2C bus specification and user manual Rev 03 19 June 2007 User manual http Awww mcc us com Open collectorFAQ htm 73 2 Accessed Nov 21 2012 Introduction to 120 http www uchobby com index php 2008 09 1 6 introduction to i2c 5 3 2 Accelerometers and MEMS Gyroscopes The sensors should consume as little power as possible and be sensitive at frequencies of zero so when the user wishes to make a small correction they won t have to provide a large input relative to the desired output The sensors will need to provide the orientation of the sections they are attached to and be ab
67. e quickly across tasks lines and teams 7 THE BAXTER 8 Fig 3 0 3 BAXTER on simulated assembly line 8 12 BAXTER claims to be quite versatile 8 Rethink Robotics Meet Baxter Fig 3 0 5 Interestingly Baxter uses a Unix based OS and open source licensing presumably as a cost saver open source license Baxter is designed to be versatile and adaptive for a wide range of jobs As such Baxter s integrated Unix based OS integrates open source licensing The open source licenses are available at the link below They are available to enable registered Baxter owners to understand the legal responsibilities and general use guidelines associated with the product 9 References 1 Accessed Oct 28 2012 1961 A peep into the automated future By PAUL MICKLE The Trentonian http www capitalcentury com 1961 html 2 Accessed Oct 28 2012 http www electronicsnews com au features robotic arm inventor george c devol dies at 99 3 Accessed Oct 28 2012 http www idemployee id tue nl g w m rauterberg presentations hci history tsId090 htm 4 Accessed Oct 28 2012 http robostuff com http robostuff com robots catalog robots by country usa unimate 13 5 Accessed Oct 28 2012 http www bootsandsabers com index php weblog permalink unimate I think this is generic historical open source content and non proprietary 6 Accessed Oct 29 2012 Historical Overview Robots ht
68. e and can do both highly repetitive assembly line welding or part placement or the extremely complex and spontaneous human operator interactive actions such as robot surgery or remote hazardous material manipulation The robotic arm is generally considered to operate in a polar coordinate system However since we are using the exteroceptive feedback system of the human operator s vision and response we should not need to program point to point locations only proportional angle rotations That is the idea Generally there are three types of actuation moving the linkages hydraulic pneumatic or electrical Hydraulic is considered the choice for heavy weight payload applications pneumatics is the choice for medium weight payloads and electrical driven systems are considered the easiest to control 1 Our project is focused on spontaneous and fine motion tracking actuation and has a very small payload demand However the robot arm could be upgraded to a heavier weight 22 design and the control system would only need more powerful motor driving current and voltage capacity Three terms that are often used with articulated robots motion are yaw pitch and roll It is best to remember them in this order and to associate them with the progressive motion of the robot arm from its base as horizontal plane of rotation around the base yaw vertical plane of rotation around each linkage joint pitch and perpendicular plane of rotation at the wrist
69. e data character The parity bit is checked by the receiver for any transmission bit errors To a host system the UART appears as an 8 bit input and output port that it can read from and write to Whenever the host has data to be sent it just sends these data to the UART in byte format whenever the UART receives data from another serial device it will buffer these data in its FIFO then it will indicate the availability of these data to the host through an internal register bit or through a hardware interrupt signal 9 Full and Half Duplex When a UART can simultaneously send and receive data this is defined as Full Duplex When a device must pause either transmitting or receiving to perform the other is known as Half Duplex meaning the UART cannot send and receive data simultaneously 7 5 4 3 2 Serial Communication Serial communication is the most common low level protocol for communicating between two or more devices Normally one device is a computer while the other device can be a modem a printer another computer oscilloscope or a function generator The serial port transmits and receives bytes of information one bit at a time These bytes are transmitted using either a binary format or in ASCII format Over the years several serial port interface standards for connecting computers to peripheral devices have been developed These standards include RS 232 RS 422 and RS 485 all of which are supported by the serial port o
70. e market for medical robotic surgery equipment looks good IbisWorld Robotic Surgery Equipment Manufacturing Market Research Report Life Sciences Medical Devices Oct 2011 reports Equipped for growth Revenue will soar as demand for complex surgeries increases The article claims a market size of 2 Billion dollars and an annual growth rate 2006 2011 of 30 7 of an industry currently comprising 33 companies and only 3 173 employees 6 The report says Industry Analysis amp Industry Trends Equipped for growth Robotic surgery equipment will continue to comprise a fast growing segment of the medical device industry Growing acceptance of minimally invasive surgery MIS will bolster industry demand as surgeons require the equipment to perform complex procedures in tight spaces While high regulations will likely inhibit profit margins and reduce innovation activity the industry will experience substantial growth in the next five years 6 What about all the industrial robots 7 31 Estimated worldwide annual supply of industrial robots 140 120 100 79 80 78 69 3 g 60 40 20 o 1998 1999 2000 2001 2003 2004 2005 2006 2007 2008 2009 2010 Source IFR Statistical Department Fig 3 3 1 And in what industries are they used 7 Estimated worldwide annual supply of industrial robots at year end by industries 2008 2010 Electrical electronics Motor vehicles Automotive parts Chemical rubber and plast
71. e other than mark when the stop bit should be present on the line it knows that there is a synchronization failure This causes a framing error condition in the receiving UART The device then tries to resynchronize on new incoming bits To resynch the receiver scans the incoming data for valid start and stop bit pairs This will work as long as there is enough variation in the bit patterns of the data words If data value zero is sent repeatedly resynchronization is not possible for example 10 5 4 4 2 1 Synchronous serial Transmission In synchronous communications the two devices initially synchronize themselves to each other and to stay in sync they send characters continually Even as data is not really being sent a constant flow of bits allows each device to know where the other is at any given time This means that each character sent is either actual data or an idle character Synchronous communications allows faster data transfer rates than asynchronous methods because additional bits to mark the beginning and end of each data byte are not required 6 With synchronous communication a clock or trigger signal must be present which indicates the beginning of each transfer The absence of a clock signal 83 makes an asynchronous communication channel cheaper to operate and fewer lines are needed in the cable A disadvantage is that the receiver can start at the wrong moment receiving the information which leads to resynchronization
72. e possible candidates for the components to our project the new MEMS gyroscopic modules a microcontroller board for the prototype phase of our project motor drivers force sensors and accessories include 36 L3GD20 L3G4200 Upgrade Triple Axis Gyro Breakout Board ID 1032 Manufactured by Adafruit 24 95 Qty Discount 1 9 24 95 10 99 22 46 100 19 96 Add to Cart fi ADD TO CART 59 IN STOCK ADD TO WISHLIST Fig 4 2 1 This breakout board is based around the latest gyro technology the L8GD20 from STMicro It s the upgrade to the L8G4200 see this app note on what to look for if upgrading an existing design to the L3GD20 with three full axes of sensing The chip can be set to 250 500 or 2000 degree per second scale for a large range of sensitivity There s also build in high and low pass sensing to make data processing easier The chip supports both 12C and SPI so you can interface with any microcontroller easily 1 and 2 Home Product Categories 3 axis SEN o9801 Triple Axis Digital Output Gyro ITG 3200 Breakout 49 9 5 SEN og801 Add to Cart Description This is a breakout board for InvenSense s ITG 3200 a groundbreaking triple axis digital output gyroscope The ITG 3200 features three 16 bit analog to digital converters 1 quantity ADCs for digitizing the gyro outputs a user selectable internal low pass filter bandwidth and a Fast Mode C 400kHz 58 instock
73. e robot arm response degrade in any way when moving while carrying a load versus initial unloaded tests 6 Again this was not done because of time constraints Types and Applications of Industrial Robots Some industrial applications of robots include material handling machine loading and unloading die casting welding inspection assembly spray painting 13 and in industries such as medical military space automobile electronics semi conductors ship building construction and aircraft and aerospace 9 The nature of our human operated motion tracking robot arm is currently used in the medical industry for robot and robot enhanced surgery and in the attempts at ubiquitous robotic manufacturing applications like Baxter http www rethinkrobotics com 7 One of the major industrial applications of robotic arms in industry is the above mentioned material handling Robots and robot arms in particular are used for palletizing stacking parts from an assembly line operation and de palletizing unstacking parts in storage and placing them onto an assembly line Ultimately our robot could be used for such an activity with significant power upgrading of all parts of the system however the nature of research in our application tends more toward cybernetic applications like robot assisted surgery or exoskeleton robotics http Awww rexbionics com Rex Bionics advertises the world s first hands free self supporting independently con
74. ed 12C SPI I2C SPI 12C I2C SPI Og Output Yes Yes Yes Yes Yes 74 Bandwidth 3200 Hz 3 200 Hz 1200 Hz 800 Hz 625 Hz Table 5 3 2 1 Electronic gyroscopes use a vibrating mass and use the Coriolis effect to measure angular velocity The differences in MEMS gyroscopes consists of the size shape resonant frequency of the vibrating mass and sensing elements as well as the way they are driven to their resonant frequency such as piezoelectric electrostatic electromagnetic One does not seem to provide a clear advantage over the other A gyroscope well be chosen mainly based on having a max angular frequency greater than that of the motor cost sensitivity and drift At this point it is important to consider the alignment between the accelerometer the gyroscope and the axis they monitor There will be an initial calibration needed to align the axis of the sensors with the axis of movement After such a point it will be integral to the control system to have the gyroscope and the accelerometer of the same axis have keep the same alignment with the axis Any shifting of the sensors would alter the necessary signal processing to obtain the correct values and could lead to system instability There are inertial measurement units IMU that are comprised of a accelerometer and a gyroscope They can have 2 or more degrees of freedom They are casted on the same IC and typically have a axis alignment error of less than 1 degree This would a
75. er magnetic or optical sensing Optical encoders can have more precision than magnetic encoders but have the disadvantage of being less resilient to shock They can output a pulse for each increment or an absolute encoder can be used that will output a a n bit word representing the rotation angle An output word of 10 bits can provide an arc length resolution of approximately 1 3 mm on shaft length of 20 cm This would be acceptable for our application If encoders are used optical and magnetic versions will be compared based on cost resolution and max shock Selection of which sensors to be placed on the robot depend on the orientation of the robotic arm to the user and the environment that it would be used If accelerometers and gyroscopes are used the robot will attempt to maintain the same orientation as the human arm regardless of the orientation of the robot If the robot is on a moving base and the base rotates the arm will rotate the same amount in the opposite direction to maintain orientation with the user If encoders are used the robotic arm orientation will be independent of the base orientation When there is not input from the user there will be no compensating rotation of the robotic arm if the base is rotated This would be particularly useful if a camera is mounted on the arm If the robot goes out of view the user will be able to control the arm as if they were standing right behind it Through the use of gyroscopes and encoder
76. ervo j 56k Fig 8 3 3 Implementation with TI LM358 N op amp References 1 Accessed Nov 26 2012 http www pololu com catalog product 1697 2 Accessed Nov 26 2012 http www pololu com catalog product 1645 3 Accessed Nov 26 2012 http www pololu com file 0J383 fsr_datasheet pdf from www interlinklelectronics com 114 8 4 Wireless Testing At the start both microcontrollers chosen by the group will be activated The microcontroller that controls the movement of the robot will connect itself with the other microcontroller via Bluetooth For that to happen the address of the microcontroller that uses the human arm sensors will already been written on the communication protocol on the first microcontroller This will allow for the two microcontrollers to begin communicating with one another The operating mode of the robotic arm is then specified by the commands that the user wants by moving their arm The analog signals from the user arm are converted to a digital signal by a Analog Digital Converter that has yet to be decided These digital signals are interpreted by the second microcontroller which processes the signals and changes them to a serial signal that contains the movement of all axes x y and z of the robot arm and the robot arm grip This serial information is then used to transmit the control signals to the other microcontroller via the Bluetooth module which is used as a replacement of a serial RS 232 cable
77. ess Robotic Series 1987 61 5 1 Design Architecture and Related Diagrams The robot controller schematic shows how the various components of the board are connected together The schematic shows the connections between the motor controllers sensors microcontroller and also the power supply required to work All of these components will be located on the same PCB which will be the main PCB for this project and will be used to control the robot This is the main PCB because all the sensor data will be directed to this board and all the instructions for the motors will come from this board Table 5 1 1 below shows all the components of this PCB Component Name Value Resistors R1 R5 1KO Servo Connectors M1 M5 Human Sensor 1 S5 Input Robot Sensor S6 S10 Input USB 2 0 connector X6 Microcontroller Atmel ATxmega128A4U Table 5 1 1 Components of robot controller This schematic shows that communication to the device will be through a USB 2 0 connection This component will be used to program the microcontroller with the control algorithm for controlling the motors on the robot given the input from the sensors on the human No other component is needed to assist with this data transfer as the ATxmega128A4U has a built in USB interface This connects to the PRO and PR1 pins of the microcontroller which are used to program the chip All of the servo motors on the robot are assigned their own pins as outp
78. he arm base which is currently non mobile Because of the close proximity of the operator to the robot arm actual motion say across a hazmat glass or plastic barrier window we hope to be able to use the exteroceptive feedback of the operator s vision to replace proprioceptive feedback additional sensors on the robots linkages 4 Initially this will significantly reduce costs and provide usable functionality If we add remote operation in the future we might have to add additional sensors to the robot arm itself 60 Our current control algorithm looks like this Operator Arm Sensors send Robot controller ippa Motion signals to robot sends signals to gt Hiii controller actuators motors Exteroceptive feedback supplied by operator s visual observance and reaction to the gripper motion Fig 5 0 7 References 1 Accessed Nov 28 2012 OWI Robot Arm Edge Assembly and Instruction Manual pdf http Awww robotshop com pdf OWI 535_Manual pdf 2 Accessed Oct 28 2012 http www 123rf com photo_11779669_human arms anatomy diagram showing bones and muscles while flexing 2 d digital illustration on white html 3 Accessed Nov 19 2012 A review of teleoperation control fcrar 2003 ppr fiu famu afrl final ver1may2003pdf http dubel org misc docs fcrar 202003 20ppr 20 20fiu 20famu 20afrl 20final 20ver 201 may2003 padf 4 Robot sensors and transducers S R Ruocco Open University Pr
79. he wrist and elbow rotation upgrades were also stock components from Lynxmotion Some servo mounting bracket modifications had to be made to accommodate some of the Solar servos It was adjudged and never proven that this customizing would not adversely affect the balance of the robot arm in motion Most of the jitter in the robot arm performance was due to not fully filtering the data from the sensors before sending commands to the motors The concern was more filtering would slow the response time Any imbalance due to mechanical construction customizations was not considered 8 5 3 Power Supply A dedicated custom power supply was never built due to time constraints however Dr Richie s suggestion to utilize a used Personal Computer power supply proved quite effective The PC p s provided the ac to dc conversion which was then utilized in a shared 5V dc power bus topology tapped from standby pin 9 on the PC supply connector 1 116 Power Supply Topology There are two basic topologies to power servo drives when operating from an AC source network 1 A Shared DC Power Bus VP VP VP VP o AC TAM DC DC DC Powerin Power Supply Servo Drive Servo Drive Servo Drive o _ VN VN VN WN One power supply runs multiple servo drives sharing one DC bus The 5V was then stepped down to 3 3V using an STM LD1117AV33 2 3 Schematic application Figure 2 Application
80. hese pins allow the programming of the memory in the microcontroller and relay debug information to the IDE on the computer during testing 87 Chapter 6 Design Summary Our design can be quickly summarized with two sets of graphics One showing the conceptual schematic and the second showing our current design of the required printed circuit board HUMAN ARM 3 3 V 5 0 V Force sensor Gyro sensor gt Atmel Micro Controller processing Power Power Supply Supply mcu motors Robot Arm Servo motors 6 possibly feedback Sensors on the arm linkages M Fig 6 1 also Fig 5 2 2 and 88 M5 1 Se oy Nid a 1 3 3 7 M a 1 M2 1 M1 L IEAA A A RP Pea Rea A ag ay ag ag ag ane Sane Sane SN Sane Sane a A A eal tel _ w 197 1dd Lasan b 8 LH be Viva idd E e a2 t A Ho a b z PE St a 5 R ra od eal 4 8s al zs x E B ra ay le gt az ya E 7 a H 8 o Fe plad 2 Oo i 4 a gg ZD 4 SY g 3d ss zad bY ez Lad V5 iv fez O34 cy g YPYIIVOJNX j b ZY g p ae Fig 6 2 also Fig 5 1 1 89 Final design implemented 0 01 uF 10 uF PR i 32 PORTE PAG a PE PA PBO PBI PB2 PBS GND1 POWER DODPVODD 1 oo i tino toor a a ATxmega128A4U MCU schematic 90 P618 Project completed ATxmega128A4U MCU 91 Other sections of the implemented design include
81. ications or measured quantity values obtained by replicate repeatability measurements on the same or similar objects under specified conditions NOTE 1 Measurement precision is usually expressed numerically by measures of imprecision such as standard deviation variance or coefficient of variation under the specified conditions of measurement NOTE 2 The specified conditions can be for example repeatability conditions of measurement intermediate precision conditions of measurement or reproducibility conditions of measurement see ISO 5725 3 1994 NOTE 3 Measurement precision is used to define measurement repeatability intermediate measurement precision and measurement reproducibility NOTE 4 Sometimes measurement precision is erroneously used to mean measurement accuracy 104 However it appears a major part of our project requires proper error measurement at least about a zero reference of the gyroscope data so the primary source is referenced again 2 2 16 3 10 measurement error error of measurement error measured quantity value minus a reference quantity value NOTE 1 The concept of measurement error can be used both a when there is a single reference quantity value to refer to which occurs if a calibration is made by means of a measurement standard with a measured quantity value having a negligible measurement uncertainty or if a conventional quantity value is given in which case the meas
82. ics Metal products Food Industrial machinery m2010 m 2009 a 2008 Communication Consumer domestic appliances Glass ceramics Medical precision amp optical instruments Others Unspecified 0 5 000 10 000 15 000 20 000 25 000 30 000 incl computers units Source IFR Statistical Department Fig 3 3 2 32 To conclude the robot industry is really just getting started at the final frontier direct human worker replacement and augmentation as direct co workers with humans in ubiquitous work environments References 1 Accessed Dec 4 2012 http www roboticsbusinessreview com 2 Accessed Dec 4 2012 The Cyborg Agenda Blurring Body Boundaries Where will the law draw the line between your intelligent prosthetic and you By Emmet Cole http www roboticsbusinessreview com 3 Accessed Dec 4 2012 Top 10 Best Jobs for Robots 2012 Help wanted humans need not apply By Tom Green http www roboticsbusinessreview com article top_10_best_jobs_for_robots_201 2 4 Accessed Dec 4 2012 Rio Tinto s 3 6B Bid to Marry Mining to Robotics Rio s Mine of the Future project and Komatsu s AHS technology seem a perfect match By Tom Green http www roboticsbusinessreview com article rio_tintos_3 6b _bid_to_marry_mi ning_to_robotics 5 Accessed Dec 4 2012 Rio Tinto s 3 6B Bid to Marry Mining to Robotics Rio s Mine of the Future project and Komatsu s AHS technolog
83. ies gets closer and closer to human mechanical and mental capabilities The INTRODUCTION section of this report illustrates the original industrial robot arm Unimate from 1961 which doesn t look much like a human arm compared with the 2012 this year Baxter which is basically a combination of two robot arms on a central body processing center with a humanoid face on video display for a head and a wheeled mobile base The focus in current robotics research and industry seems to be quick and simple implementation in the workplace with the robot being functionally programmed by non robotic personnel general workers Baxter s co workers A general trend in robotics is increasing autonomy from the 2006 UCF senior design project DUCSS on DARPA autonomous vehicles referenced in OTHER 20 PROJECTS to the more famous Google Cars or the currently available option in some cars of automated parallel parking autonomy from machines in previously human only functionality is on the rise Google s constant attempts to spread it s arms above it s search engine and advertisement placements has brought in an experimental robot car that drives all by itself under the supervision of a human safety driver just in case the car needs help Google s blog said that it all works with the help of video cameras radar sensors and a laser range finder to see other traffic as well as detailed maps collected by their manually driven vehicles to navigate the r
84. ign utilizing cost feasible components Our final design accomplished the initial performance objectives within a reasonable range of our initial budget 400 800 A significant upgrade for about 100 would have been to replace the base servo HS645 133 oz in from the original AL5D arm with a much stronger servo HS805 343 oz in and new bracket arrangement both available from Lynxmotion However time ran out before the arm motion justifying the additional expense was developed Additionally wireless functionality was not attempted Wireless capability could have been added for perhaps 100 Another micro controller would have to be included also to connect wirelessly from the sensors on the human arm controller to the controller on the robot arm At the end of the project the crucial first problem of successful coding of the gyroscope sensor data into effective motor driving response was not accomplished Accelerometer data only was used to sense the human operator s arm motion and drive the servos Additionally because the project ended at the 119 absolute minimum completion of the build phase no real system evaluation was performed Chapter 10 EEL4915 Design Implementation 10 1 System Final Design Summary 6 1 DOF 6 rotational 1 translational robot arm Added wrist and elbow to original AL5D 3 6 axis gyro accelerometers custom pcb 3 3V 1 Shared DC Power bus servo power supply PC power supply 5V to servo connector boa
85. in coding before we send the printed circuit board out to be made See section 7 1 Parts Acquisition References 1 Accessed Nov 11 2012 https www adafruit com products 1032 2 Accessed Nov 11 2012 https Awww sparkfun com products 9801 41 3 Accessed Nov 11 2012 https Awww adafruit com products 191 4 Accessed Nov 11 2012 https Awww adafruit com products 807 5 Accessed Nov 11 2012 https Awww adafruit com products 81 6 Accessed Nov 11 2012 https www adafruit com products 973 7 Accessed Nov 11 2012 http www futurlec com ICAtmel shtml 8 Accessed Nov 11 2012 http www digikey com scripts DkSearch dksus dll WT z_supplier_id 313 amp WT z _page_type SP amp WT z_page_sub_type SS amp WT z_oss_type Keyword amp v 3138 amp l ang en amp site us amp KeyWords Atmel AT xmega1 28A4U amp x 1 3 amp y 8 9 Accessed Dec 5 2012 https www sparkfun com products 10736 4 2 0 H W UPGRADE OPTIONS If the OWI 535 1 doesn t meet necessary performance criteria some hardware OWI 535 Robotic Arm Edge Product code RB Owi 41 Qty Price 1x USD 44 29 5x USD 42 52 25 x USD 40 82 O Z In Stock ADD TO MY PREFERRED LIST 53 TELLAFRIEND SHARE g 2 27 Fig 4 2 1 42 upgrade options include 2 Home Robots Robot Kits Robot Construction Kits Lynxmotion Erector Set Lynxmotion ALSB 4 Degrees of Freedom Robot Hardware Only Product code RB Lyn 268 Qty Price
86. istory 2 UNIMATE the first industrial robot began work at General Motors Obeying step by step commands stored on a magnetic drum the 4 000 pound arm sequenced and stacked hot pieces of die cast metal The brainchild of Joe Engelberger and George Devol UNIMATE originally automated the manufacture of TV picture tubes 3 A picture of the first Unimate 4 Fig 3 0 1 A picture of the first Unimate at work 5 10 Armed for duty A Unimate robot really just an arm picks up and puts down parts in a General Electric factory Fig 3 0 2 lt was an automated die casting mold that dropped red hot door handles and other such car parts into pools of cooling liquid on a line that moved them along to workers for trimming and buffing Its most distinct feature was a grip on a steel armature that eliminated the need for a man to touch car parts just made from molten steel 6 To jump to the present and take a look at the current state of industrial robotics and the new leading edge take a look at Baxter rethink productivity Baxter our flagship product is America s first adaptive manufacturing robot Designed to use common sense and work safely alongside people it ll take your productivity to new heights and deliver a true competitive edge rethink affordability 11 A game changing price point Trainable by non technical personnel with no costly programming needed And flexible and adaptable enough to chang
87. ld have been obtained by using both the gyroscopic data and accelerometer data Again because of time constraints the FSR end effector control was replaced with a button activator of the gripper 10 6 Project Conclusion do anything different There is no way to deny the project performance was severely handicapped by the seven week delay caused by a design change from 4 1 directly to 6 1 DOF acquiring elbow rotation hardware and component original servos purchase delayed delivery For build and test purposes the project did not progress from the eel4914 design and plastic prototype built between terms from early January until late March The number one thing that should have been done different is building a learning curve of increasing familiarity with the hardware capabilities of the components and specific component software programming skills Jumping directly to 6 1 DOF was a very bad idea because of the uncertainty not dealt with in the intermediary 4 1 and 5 1 DOF phases of development accumulated into very rough final performance Without question maintaining the build and test schedule is crucial to proper project development and execution For a final comment the executive summary begins with a statement of eel4914 4915 objectives To provide students a complete design experience including the necessity to set design goals and objectives integrate knowledge exercise engineering judgment plan to meet a budget and
88. le to give the speed and direction of which they are moving Electronic accelerometers gyroscopes and compasses are capable of handling the task of sensing the movements of the human arm because of their low power consumption small size and their ability to accurately measure their respective forces There are three main types of sensing elements used in electronic accelerometers They are piezoelectric materials piezoresistive materials and variable capacitance Piezoelectric accelerometers have a frequency range of a few Hz to 30 kHz or more They are readily available in a number of different packaging options and sensitivities but there inability to accurately measure steady state response does not make them desirable for the application of a human motion sensing replication where the frequency is in range of 0 Hz to less than 100 Hz Piezoresistive accelerometers have a frequency response that includes 0 Hz but are less sensitive than piezoelectric accelerometers They are typically used in shock measurements Variable capacitance accelerometers respond at 0 Hz have good temperature stability and high sensitivity Some accelerometers considered are shown in the chart below es ADXL346 ADXL362 BMA180 KXCJK LIS3DH 2g Capable Yes Yes Yes Yes Yes Output Data 1600 Hz 400 Hz 2400 Hz 1600 Hz 1 25 kHz Rate Max Sensitivity 3 9 1mg LSB 3 4mg LSB 0 98mg LSB 1mg digit mg LSB Nonlinearity 0 5 0 5 0 15 0 6 Not Provid
89. lf synchronizing 7 5 5 Controller Subsystems As mentioned before the main control board for this project will be responsible for reading the input from the sensors translating to a position for the motors and then outputting that position to the motors These actions are possible due to several subsystems on the control board 5 5 1 Microcontroller A major piece on the control board is the microcontroller As explained in section 4 2 1 the microcontroller is responsible to interpreting the data from the sensors and computing motor position Microcontrollers are essentially whole computers contained on a single integrated circuit that contain a processor core memory and programmable input and outputs The microcontroller that will be used for this project is the ATxmega128A4U This microcontroller is made of many different parts that allow it to interpret the data passed to it and compute outputs The block diagram of the ATxmega128A4U is shown below in figure 5 5 1 85 PA O 7 e Controller Prog Debug mas ocb BUS Matrix PCiO 7 POjO 7 PE O_3 Figure 5 5 1 Block diagram of the ATxmega128A4U microcontroller One of these parts is the analog to digital converter This component is a vital part of allowing the microcontroller to do its job for this project The A D converter takes in a signal from an input port measures the voltage of that signal and converts it to a digital value This allows the microc
90. lso guarantee only a small compensation is needed some manufacturers ship IMUs with the alignment error already compensated when compared to the compensation that would be needed to align individual components soldered on a PCB board Having the accelerometers and gyroscopes would save space on the board and possibly speed up the transmission of sensor data between the different sections to the control board It is dependent on the how the IMU is capable of sending data Many 6 degree of freedom IMUs communicate via a bus line having already done the analog to digital conversion and some signal processing on the data before transmitting it to the controlling processor to free up resources the controlling processor would have had to utilize before moving on to the next task However IMUs can be very expensive For this project we will build or purchase the necessary parts to create a sensor system that can measure acceleration and angular velocity along all axes of rotation The outputs of the accelerometers and gyroscopes may be analog In order to transmit the information to the control board there will be some protection from noise Some options will be using shielding to protect the data from noise or do analog to digital conversion near the sensors and transmit the information digitally so that it is more resistant to interference The problem with the use of shielded wire for analog outputs is that there will be at least 18 wires ran from the c
91. lso integrated with a library of source code for example programs The use of C for the program language and the availability of various libraries would allow minimal effort in learning how to program for this specific microcontroller A final microprocessor considered for this project was the Propeller 40 pin DIP made by Parallax This microprocessor has 32 I O pins and 64 KB RAM ROM The amount if I O pins is sufficient for this project The amount temporary is also large enough any temporary variables that might be needed The memory does lack any EEPROM or other semi permanent storage for the control algorithm to be stored in as well as variables such as default states This lack of permanent memory would require an external memory device and would take up board space The Propeller does lack an A D converter which affects a requirement for the microcontroller used for this project In order for the Propeller to do A D conversion it must rely on the manipulation of two of its registers This would take up computing time and slow down the reaction of the robot which needs to be fast Parallax provides an IDE to program their Propeller microcontrollers The Propeller microcontrollers have a unique architecture for microcontrollers in that they have eight processors that Parallax calls cogs These processors are able to act independently of each other allowing the microcontroller to process many different things at the same time Due to this unique ar
92. m industrial htm 12 Accessed Dec 3 2012 The Role of Robotics in Flexible Manufacturing March 3 2009 http www assemblymag com articles 86147 the role of robotics in flexible manufacturing 13 Robotics an Introduction Delmar Publishing Inc 29 ed 1988 p 312 Douglas R Malcolm Jr http www robotmatrix org 28 14 Robotics an Introduction Delmar Publishing Inc 2 ed 1988 p 387 Douglas R Malcolm Jr http www robotmatrix org 15 Accessed Dec 3 2012 Robotics Engineer http www learnaboutrobots com roboticsEngineer htm 16 Accessed Dec 3 2012 http www rexbionics com 17 Accessed Dec 3 2012 http www thefreedictionary com cybernetic 18 Accessed Dec 3 2012 Power Sources for Small Robots http www ri cmu edu pub_files pub1 dowling_kevin_1997_1 dowling_kevin_199 7_1 pdf 19 Accessed Dec 3 2012 Robot Systems Power http prime jsc nasa gov ROV systems html power 20 Accessed Dec 3 2012 The Road to Universal Robots 2005 The Tech Museum of Innovation http www thetech org exhibits online robotics universal page1 2 html 21 Accessed Dec 3 2012 http en wikibooks org wiki Robotics Design_Basics What_you_should_know 22 Accessed Dec 3 2012 http www robotshop com all robot sensors html Note in Appendix Permissions Disclaimers refers section 3 2 and Copyright notification 3 3 Robot Business According to the Wiki site on Industri
93. mate to Baxter 2 Initial feasibility investigations of the project included web searches for similar projects and several were found on YouTube and are illustrated in the section 3 1 Similar Projects Other projects reviewed more closely included previous EEL4914 projects from 2006 DUCSS a DARPA autonomous vehicle sensor system and a 2009 project Luke s Hand an attempt at a human prosthetic robotic hand From searching robot websites and robot shop sales forums sites an initial concept of the design was determined MEMS motion sensors and a force sensitive resistor would provide the sensing of the human operator s arm and hand motions an Arduino type microcontroller would process the sensor data and generate signals through a motor dc driver subsystem not needed with subsequent servo motors to drive the robot arm motors 3 Because Robotics is virtually a graduate school field of study section 3 2 General Research on Robotics as relates to our project was added to connect our project to the more general knowledge base of robotics 4 The core design of the project is the software interfacing the sensors to the motors through the control board explained in section 5 1 Design Architecture and Related Diagrams Fulfilling the project requirement for at least one custom designed printed circuit board the control board design accomplished the control requirements of the project and e Contain enough I O pins to monitor all the sensors and
94. microcontroller used was the Propeller 40 pin DIP which does not have a built in 54 A D converter or any internal EEPROM The choice in microcontroller required an external A D converter and an external EEPROM unit Having these built into the microcontroller frees space on the board and allows for sensors to be plugged directly into the microcontroller This also prevents the microcontroller from having to load the algorithm from the external storage on startup saving some time Below is a picture detailing the architecture for the control board of Luke s Hand Pp Servos u4 5468 VIN LT323 youT GND ic3 e C4 if sgi tE 75 tur T 3 3v xL Re pu 10K SMHz 3 A A cj oj j w 1 a oO mom a f j om a Nj wo af aj wl af Af ww aj of f Oo af af al a R RB a j j aj aj gt X x gt a af aj aj aj a aj a ewneoere raona nena SSSR SERM e 8 CBRE LE Propeller P8x32A D48 on um en a o oaenvrn aot ISIS a w SB c cla M wl ol sl el el sl a Sa 8 el el 8 eg g gy el aj ala l al 9 9 w 5 al aj aj af aj aj a al v 3 3 La Senior Design II Luke Hand s Controller Group 6 Reo 1 8 Page 1 Toup 1171372009 Figure 4 3 2 Luke s Hand control board schematic Chapter 5 Design Details 5 0 Initial Design Concept
95. nough to not have the frequency drift by more than 10 during the transmission of the remaining bits in the word data_bits OSS HONN start_bit stop_bit start bit input first data bit transition 12 cycles later detected When the entire data word has been sent the transmitter may add a Parity Bit that the transmitter generates The Parity Bit may be used by the receiver to 84 perform simple error checking Then at least one Stop Bit is sent by the transmitter When all of the bits in the data word have been collected in the receiver it may check for the Parity Bits where both sender and receiver must agree on whether a Parity Bit is to be used in the first place and then the receiver looks for a Stop Bit If the Stop Bit does not appear when it is supposed to the UART considers the entire word to be garbled and will report a Framing Error to the host processor when the data word is read The usual cause of a Framing Error is that the signal was interrupted or both the sender and receiver clocks were not running at the same speed Regardless of whether the data was received correctly or not the UART will automatically discard the parity stop and start bits If the sender and receiver are configured identically these bits are not passed to the host If another word is ready to be sent the start bit for the new word can be sent as soon as the stop bit for the previous word has been sent Long story short the asynchronous data is se
96. ntain a good speed of connection without much loss 2 This faster speed utilized through Bluetooth helps in improving a goal set for this project involving a fast and precise response time of the robot arm to the user movement Based off of those factors and a couple others the group has decided to control the wireless communication via Bluetooth For purposes of demonstration the robotic arm does not need to be controlled at a far distance and the arm will be transferring data between a pair of microcontrollers which is better served through Bluetooth connection 78 5 4 2 Bluetooth background Bluetooth wireless technology as stated before is most beneficial for short range communication with key features based around low power durability and cheaper cost Bluetooth was designed to make use of radio frequencies doing away with cables connecting portables and or fixed devices Bluetooth technology has achieved global acceptance such that any Bluetooth enabled device almost everywhere in the world can connect to other Bluetooth devices that are within range 2 5 4 2 1 Communications range A signal can be affected in different ways due to different environments This leads to an issue of not being able to exactly determine the transmitting range of the Bluetooth device class The best way to compare a devices operating range is by measuring another devices operating range and equate the output power That is because a higher
97. nto the boards plus miscellaneous items needed for construction board components plus shipping costs etc It is a significant point of comment that even at minimum wage per hour cost allocation for design and build of the printed circuit boards there is little if any savings over purchasing the boards directly from vendors For instance the three 6 axis sensors boards could have been purchased for 50 each and 10 for shipping for total cost of 160 The basic component costs of the self made sensor boards was not less than 70 including shipping even at only three hours total for design and build very low compared with our group s experience the total cost is easily over a 100 travel costs to campus to use the radio club smt machine 10 contribution to the radio club more etc s A very similar calculation applies to the custom construction of the mcu ATxmega1284AU used in the project 8 The build plan for the project was already started as mentioned above with the successful build of the plastic OWI robotic arm Final prototype electronic parts selection was derived from the control board design and component acquisition was begun in late December and early January Details for building the prototype and final Helping Hand are in Chapter 7 Build Plan A list of components acquired is also in Chapter 7 Although the metal arm was acquired by the end of January a decision to delay the build while acquiring the elbow rotation a
98. nvironment and make changes in their behavior based on the information they have gathered 19 Another sensor employed in our project is an FSR force sensitive resistor that communicates to the robot arm whether the end effector is to remain open or be closed around an object The force sensitive resistor works by changing decreasing its resistance as a force is applied to the contact area and is explained in detail in the section HOW FORCE SENSORS WORK A quick web search of online robot shops identified a multitude of varied and frequently quite sophisticated sensors 22 Laser range finders accelerometers gyroscopes compass modules GPS modules light detectors barometric pressure and moisture sensors and many more readily available for mostly under 100 or even 50 For the plastic prototype our project only employed one MEMS gyroscope sensor 3 DOF Some type of simple feedback sensor like potentiometers might be employed on the robot arm joints For details on how the gyro sensors work see section 4 3 2 How Gyros Work 23 Processors In what are called low technology applications robots are controlled by cams and valves called hard automation systems Reprogramming is a problem 1 Obviously our robot arm is controlled by microprocessor power on a printed circuit control board The controller is the robot s brain and controls the robot s movements It s usually a computer of some type which is used to store information about the ro
99. o give the same reading when returned to the same position 8 This again depends on the programming of the gyro sensors This also was not done because of time constraints Finally resolution is alternatively defined as The smallest increment of motion or distance that can be detected or controlled by the robotic control system 6 or a measure of the ability of the transducer sensor to break down the angular position into fineness of detail in a spatial pattern 8 The gyroscope data is extremely well resolved in tenths hundreds and even thousands of degree per second accuracy Additionally a specific definition of envelope s 25 Envelope A three dimensional shape that defines the boundaries that the robot manipulator can reach also known as reach envelope e Maximum envelope the envelope that encompasses the maximum designed movements of all robot parts including the end effector work piece and attachments e Restricted envelope is that portion of the maximum envelope which a robot is restricted by limiting devices e Operating envelope the restricted envelope that is used by the robot while performing its programmed motions Reach The maximum horizontal distance from the center of the robot base to the end of its wrist 6 Yet another consideration is payload the maximum weight or load the robot can lift and how the robot performs both unloaded and loaded in terms of speed response Does th
100. o this pin A logic input control for motor channel B PWM can be applied to this pin Sleep input when this pin is driven low the chip enters a low power sleep mode Labeled SLP on the board silkscreen Fault output driven low in the event of an over current over temperature or under voltage condition floating otherwise Labeled FLT on the board silkscreen Current sense pin for motor A This pin is connected to ground and does not function by default but current limiting can be enabled by making the modifications described below Current sense pin for motor B This pin is connected to ground and does not function by default but current limiting can be enabled by making the modifications described below Table 5 2 1 A schematic of the DRV8833 1 68 VMM R3 47k SLP Schematic diagram of the DRV8833 dual motor driver carrier Fig 5 2 5 References 1 Accessed Nov 17 2012 http www pololu com catalog product 2 130 2 Accessed Nov 17 2012 http www pololu com catalog product 713 5 2 2 MOTORS The current robot arm being used for initial testing uses small cheap dc motors If the design has success with basic motion requirements of the master slave robot arm a hardware upgrade to servo motors and a faster response mechanical arm will be undertaken In general robotics uses three different types of motors to implement linkage translations and rotations dc motors stepper motors and
101. oad ahead The car drives quite well on it s own 2 The Darpa Grand Challenge started in 2004 and is well under way to achieve its goal to make one third of all military vehicles autonomous by 2015 pending funding 3 Beginnings Robot as a word and concept is less than a hundred years old Somewhere in the first half of the 20 century automated machines began to appear in manufacturing and became increasingly prevalent through the end of the century Robots now perform many high tolerance machine performances particularly in Integrated Circuits and MEMS _ micro electrical mechanical systems manufacturing that could never be accomplished by humans alone Robots are increasingly being used to facilitate high tolerance surgery on human bodies both directly by the surgeon or remotely or even autonomously Robotic surgery on the other hand requires the use of a surgical robot which may or may not involve the direct role of a surgeon during the procedure 7 Suffice to say robots are here to stay A More Technical Survey of Robotics A robot consists of sensors processors actuators and power sources Actuators include components such as motors and the linkages the motors are driving and end effectors located at the end of the linkages to grasp or otherwise manipulate objects Processors vary from small embedded systems micro controllers to laptop or desktop pc s to even larger mainframe computer controlled robots Power
102. oducts 1032 These sensors use 12C or SPI to communicate 2 pins 12C or 4 pins SPI are required to interface Adafruit invests time and resources providing this open source code please support Adafruit and open source hardware by purchasing products from Adafruit Written by Kevin KTOWN Townsend for Adafruit Industries 132 BSD license all text above must be included in any redistribution RENEE EERE EEA ee REE EES ARE RAL EEAS EE ACE EEE Ee Adafruit_L3GD20 Adafruit_L8GD20 cpp HEIR ISIS IAI II III This is a library for the L8GD20 GYROSCOPE Designed specifically to work with the Adafruit L3GD20 Breakout gt https www adafruit com products 1032 These sensors use 12C or SPI to communicate 2 pins 12C or 4 pins SPI are required to interface Adafruit invests time and resources providing this open source code please support Adafruit and open source hardware by purchasing products from Adafruit Written by Kevin KTOWN Townsend for Adafruit Industries BSD license all text above must be included in any redistribution SERRE EEE ETE EE REELS EAL LE RARER EL EEA ERE SEAL EE ERA ERS include lt Adafruit_L3GD20 h gt PRERENDER MeN nae hehe tae POO nae LOO an Re Nee Ae A ete Sean Adafruit_L3GD20 README md endif This is a library for the Adafruit Triple Axis Gyro sensor Designed specifically to work with the Adafruit L8GD20 Breakout gt https Awww adafruit com products 1032 These sensors use 1
103. ology 201 2 1 2 industrial robotics market global industry size market share trends analysis and forecasts 2012 2018 2502558 html 34 Chapter 4 Research Related to Components 4 1 Relevant Technologies Some technologies that will be looked at as relevant to our project of a master slave motion tracking robot arm include MEMS and IC manufactured components artificial intelligence simulation and computer programming 4 1 1 MEMS and IC MEMS micro electrical mechanical systems are based on the IC integrated circuits thin film manufacturing technologies and then add the magic of under etched free standing structures that create dynamic and useful electro mechanical transducers such as the gyroscopes used in our design proposal see next section POSSIBLE COMPONENTS Of course the microprocessor on our control board is a product of IC manufacturing technologies 4 1 2 Artificial Intelligence Al Artificial Intelligence is the brains of computers and robots Al is how humans program intelligence into machines Nominally Al is math logic combined with computer programming logic to simulate human decision making intelligence in computers and machines Al is generally associated with very difficult computer programming applications We have not started programming our sensor controller actuator system yet so we do not know if our programming demands are at an Al level of difficulty It can be argued that any embedded sys
104. ontrol board There will be at least 9 wires ran to each sensor This can led to the difficulty of securing each wire so that it will not be pulled out as the arm 75 makes various movements or introduce noise from its movement A better option will be to use a bus to transmit the data to the control board The robotic arm offers more flexibility in the selection of sensors Besides the use of accelerometers and gyroscopes incremental encoders or variable resistors can be used which have some advantages To process the orientation from an accelerometer the three axis s values must be obtained and processed in order to calculate the rotation in a gravitational field Incremental encoders and variable resistors can be discretized to represent the rotation angle of the joint it is monitoring A disadvantage of variable resistors is that they must have a constant supply voltage or their output will change with voltage as well as resistance This can be accounted for in a circuit such as an instrumentation amplifier comparing supply voltage and output voltage however this requires additional circuitry at the joint and will have an analog output that will have a greater susceptibility to noise than a digital output The maximum number of discrete levels will be dependent on the noise level in the signal Incremental encoders produce digital outputs so will be better suited for environments where electrical interference may be present Encoders are eith
105. ontroller to communicate with devices that output voltage levels as data on one wire instead of using several wires to produces a digital value This subsystem of the microcontroller not only saves I O pins but also saves space on the PCB board as an external A D converter is not necessary when one is built in A second subsystem of the microcontroller is the PWM pulse width modulator This feature of the microcontroller allows it to produce a signal that is used to 86 control external objects such as power converters and motors PWMs are a digital signal in the form of a square wave with a varying duty cycle The length of the signal is used by the receiving device to determine what operation to take in a motor s case what position to move to This feature allows the microcontroller to control the motors in the robot and eliminates the need for a separate motor controller on the control board 5 5 2 Power Supply A pivotal component of the control board is how to provide power to all of the different parts Most parts of this project are powered directly from the control board including the microcontroller and the motors in the robot One problem with supplying power to the different components of the control board is that some components operate at voltages that are too high or too low for the other components to operate at This requires control over the voltage from the power source and one way to do this is through voltage regulators
106. order to test the functionality of the IMUs to be used the board will be placed on an apparatus that can test the steady state values of the accelerometers at different angles and the drifting of the measurement The apparatus will also be rotated some number of degrees rotated back to its starting position and integrated to test the accumulated error of the accelerometer The power used by the unit will be measured to determine the necessary power to provide and the duration it can be operated off of a battery The gyroscopes will be rotated on the apparatus at different constant velocities and different angles to measure their output and test for linearity Any deviation from the expected values will be accounted for in the control algorithms These tests will also allow for a testing of the communication between the sensors and the control board 8 3 1 HOW FORCE SENSORS WORK Tested FSR Force Sensing Resistor 1 5 inch square shown below with ohmmeter successfully We are considering the following sensors for use as the end effector open close control sensor 2 Force Sensing Resistor 1 5 Square Pololu item 1645 814 in stock Price break Unit price US 1 5 45795 10 7 16 100 5 59 cut rT backorders allowed This force sensing resistor FSR from Interlink Electronics is a passive component that exhibits a decrease in resistance when there is an increase in the force applied to the 1 5 x1 5 38x38 mm active area all
107. ors with plus or minus 3 Volts driving the motors direction in forward or reverse at about 1 amp current While small robotic applications Power system alternatives include batteries fuel cells and generators thermoelectric generators super capacitors flywheels and even non storage options such as tethers electric cord 18 our project really doesn t require any such exotic considerations However we use a 3 3 Volt power supply to drive the control board including the motor driver output signals and 5 volts to drive the servo motors on the metal arm Power for industrial robots can be electric pneumatic or hydraulic Electric motors are efficient require little maintenance and aren t very noisy 19 There is quite a bit more info about pneumatic and hydraulic power sources that is not 24 relevant to our small robotic arm project Nor will we be using solar power or radioisotope thermal generators System Control Initial considerations of system control are the parameters DOF degrees of freedom accuracy repeatability and resolution 1 6 Degrees of freedom is defined as the number of independent ways a mechanism can move In our initial robot arm design there are five degrees of freedom one horizontal rotation around the base and three vertical rotations shoulder elbow wrist and one translation movement gripper jaws open close We might add another degree of freedom with the rotational wrist upgrade option on the metal arm
108. ot so that the data from the robot matches that of the operator Having all of the listed 45 requirements will allow the microcontroller to be integrated into and meet the specifications for the project In addition to the requirements for microcontroller there are other factors to consider What language the microcontroller can be programmed in is one such factor A microcontroller that can be programmed in C will be easy to use as it is a higher level language that the members of this project have experience with Another factor to consider is an analog to digital convertor to read the signals sent by the sensors and convert them to usable data For the robot to be able to respond at an acceptable speed the microcontroller must be at to process instructions quickly and the number of instructions it can process per second is another important factor to consider One microcontroller looked at for this project was the Nano 28 made by Basic Micro This microcontroller has 24 I O pins 14 KB of memory 368 bytes of RAM and 256 bytes of EEPROM This microcontroller has enough I O pins to handle all of the sensors that will be on the controller and robot as well as the motor controller The amount of program space should be sufficient to hold the control algorithm for the robot and the amount of EEPROM is enough as that would be used to store default positions for the motors The amount of RAM is also sufficient as that would be used to save the current v
109. ould start with the base motor of the robot attempting to cause it to rotate from one extreme to another The program would then attempt the same procedure for all other motors on the robot one at a time This test would show that the signals for the motor are properly connected and that the microcontroller has the ability to control each motor The next test would be to check if the microcontroller is receiving the input from the sensors To test this the operator connected the sensors to the control board and began to move one If the microcontroller was receiving a signal from the sensor then it would move the motor associated with that sensor from one extreme to another The operator then repeated this procedure for all of the other sensors individually and ensured that the motor associated with that sensor moved when the sensor did This test showed that the microcontroller is receiving the signals from the sensors and is relating it to the proper motors 8 5 1 Circuit Assembly The printed micro controller circuit board like the sensor boards was assembled with the Radio Club s surface mount soldering machine The boards were then populated with necessary components by team members Eric Donley and Matt Carlson Basic electrical continuity checks were done before electronic testing with the motors and sensors 8 5 2 Robot Arm Assembly The Lynxmotion AL5D robotic arm was stock as are the Solar and Hi tec servos used to actuate the arm T
110. output power leads to a longer range of use The three classes of Bluetooth are listed below 3 e Class 1 Long Range Maximum Output Power of 100mW up to 100 meter range e Class 2 Medium Range the most common Maximum Output Power of 2 5mW up to 10 meter range e Class 3 Short Range very rare Maximum Output Power of 1mW up to 1 meter range Class 2 devices are most common in modern day consisting of cell headsets laptops cell phones and any other consumer level Bluetooth devices Of the two or more devices communicating the higher class of such devices determines the properties Say a class 2 Bluetooth cell phone communicates with a class 1 USB device the cell phone will limit the range of the Bluetooth radio Due to their limited range affecting their usefulness it is rare to see a class 3 device 5 4 2 2 Device Name Bluetooth devices will have a user friendly name majority of the time Unlike Internet names the user for Bluetooth may choose any unique name they desire without requirement though it can lead to confusion when multiple devices within the range limit also have the same name A scenario where someone is sending a file from their phone to another the user may have to decipher between three or four other phones all with the same title My Phone This name selected by the user is shown rather than the Bluetooth address to identify a device due to 79 people having problems recognizing or remembering
111. owing you to create a sensor that is able to detect force or pressure The polymer thick film PFT device is optimized for use in human touch control of electronic devices and can sense an applied force ranging from a few dozen grams to over 10 kg 22 Ib Or 1 110 Force Sensing Resistor 24 x 0 25 Strip Pololu item 1697 36 in stock Price break Unit price USS 1 17 95 10 16 16 Quantity 1 Add to cart 7 backorders allowed www pololu com Add to wish list Len This force sensing resistor FSR from Interlink Electronics is a passive component that exhibits a decrease in resistance when there is an increase in the force applied to the 24 x0 25 610x6 3 mm active area allowing you to create a sensor that is able to detect force or pressure The polymer thick film PFT device is optimized for use in human touch control of electronic devices and can sense an applied force ranging from a few dozen narams tn aver 19 ka 2 Ih The devices have significantly different costs 5 45 1 5 inch square and 17 95 0 25 strip respectively and operate on the same principle of increasing pressure on the sensor generates a decrease in resistance across the device Specifically designed for use in human touch electronics the FSR force sensing resistors are polymer thick film devices which exhibit an almost linear response when graphed in log log format 3 RESISTANCE kQ grams FORCE
112. pe microcontroller the prototype development was not pursued any further A note here that human response time to external stimuli is generally considered not faster than 0 10 second 6 A first milestone was achieved Nov 4 with the successful build of the robot arm OWI 535 EDGE see Fig 4 2 1 which is made from all plastic parts except for the motors and self tapping fastener screws and has a simple manual controller arrangement double throw switches that are manually thrown 3 Vdc to rotate clockwise and counterclockwise the five dc motors of the 535 arm Female jumper pin wires from each dc motor were easily accessed to connect our own motor drive system 7 The low budget estimate of 400 was raised to nearly 800 see section 10 4 System Budget by the completion of the project The OWI arm only cost 40 but it only provided proof of concept of our electronic control system For presentation level of performance we upgraded see section 4 2 0 H W Upgrade Options to a Lynxmotion AL5D metal arm for 130 with elbow and wrist rotation upgrades costing an additional 30 each and seven servo motors costing about 100 plus two large base and shoulder replacement servos at about 100 Another cost overrun was that even though the 6 axis sensors gyroscopes accelerometers were acquired from Ebay for 20 for four mpu 6050 sensors the pcb cost was 30 and then a stencil had to be acquired for 10 to surface mount solder the sensors o
113. permission request in writing to Permissions Dept Questex Media Group LLC 275 Grove Street Suite 2 130 Newton Massachusetts 02466 or fax to 617 219 8310 2 Accessed Nov 21 2012 http www sensorsmag com files sensor nodes 2003 970 fig6 jpg also displayed on source 1 http www quora com How does a MEMS gyroscope work webpage exact same jpg from 3 different sources think it is open source content 3 Accessed Nov 22 2012 Introduction to MEMS gyroscopes http www electroiq com articles stm 201 0 1 1 introduction to mems gyroscopes html sent for permission 11_ 30 for both an online contact us form no response as of 12_5 4 3 Example Architectures and Diagrams Many assembled control boards were viewed while researching parts for this project Most of these examples had schematics that were viewable to study the architecture of them These diagrams were useful for researching what components a control board would need to have and how they should be laid on the pc board One control board that was studied for this project was the Arduino Leonardo seen in figure 4 3 1 Arduino builds control boards that are meant to be used to develop interactive objects These boards can handle input from sensors 52 switches and control physical objects such as motors and lights The Arduino Leonardo has 20 I O pins 12 of which can be used as analog inputs a micro USB connector an ICSP header a reset b
114. r drivers considered for the design are the TB6612FNG Dual Motor Driver Carrier by Toshiba from Pololu Robots and Electronics 8 45 and the DRV8833 Dual Motor Driver Carrier by Texas Instruments and also acquired from Pololu 6 95 66 This tiny breakout board for T s DRV8833 dual motor driver can deliver 1 2 A per channel continuously 2 A peak to a pair of DC motors With an operating voltage range from 2 7 to 10 8 V and built in protection against reverse voltage under voltage over current and over temperature this driver is a great solution for powering small low voltage motors 1 Also the Toshiba board and Pololu This tiny board is an easy way to use Toshiba s TB6612FNG dual motor driver which can independently control two bidirectional DC motors or one bipolar stepper motor A recommended motor voltage of 4 5 13 5 V and peak current output of 3 A per channel 1 A continuous make this a great motor driver for low power motors 2 Although the Toshiba says it is rated with a minimum of 4 5 volts and our current robot arm dc motors are rated at 3 volts online forum advice has communicated that there is about a 1 2 voltage loss across the drive transistors in the H bridge chips so 4 5 volts should also work ultimately our design has to drive 5 dc motors if these two both work at least one more motor driver will be needed A generic schematic of the DRV8833 1 Using the motor driver motor power 2
115. rd 3 3V to sensors and mcu 1 Micro controller board custom pcb 3 3V 1 Button gripper controller 3 3V No wireless The final design implemented in eel4915 in the spring of 2013 features both the wrist and elbow upgrades additional joints considered in eel4914 from the fall of 2012 Wireless operation was not able to be implemented because of time constraints The completed design is a 6 1 DOF haptic robotic arm controlled by 3 InvenSense 6 axis gyro accelerometers mpu 6050 driving six 6V 4 8 6 0 volts servo motors of varying torque capacity A seventh servo controlling the opening and closing of the end effector gripper was controlled by a button trigger arrangement held within the human operator s palm of his hand All sensor signals are input to the ATxmega128A4U microcontroller unit and all output signals sent directly to the servo motors A pc supply power was configured as a Shared DC Power bus servo power supply to energize all seven servo motors and all sensors and the microcontroller unit Basic working amperage is about 3 to 4 amps however if the six rotating servos all went into stall at once current demand could exceed 9 amperes 10 2 System Construction Final construction is best explained with the following photos showing the vertically mounted arm and adapted personal computer power supply connected to the servo and sensor control board The sensor sleeve connects the sensor inputs to the mcu board and the mcu boar
116. rent through the FSR should be limited to less than 1 mA square cm of applied force Suggested opamps for single sided supply designs are LM358 and LM324 FET input devices such as LF355 and TL082 are also good The low bias currents of these op amps reduce the error due to the source impedance of the voltage divider A family of FORCE vs VOUT curves is shown on the graph above for a standard FSR in a voltage divider configuration with various RM resistors A V of 5V was used for these examples The fsr_datasheet pdf includes additional adjustable buffer application circuits allowing the adjustment of gain and offset as well as multi channel micro controller interface for multiple FSR applications Our design should only need one FSR and probably the larger 1 5 inch square sensor in case the wrist gyro and force sensor need to mounted on a glove to maintain permanence of the human arm operator s equipment arrangement The datasheet includes a design for a variable force threshold switch for applications that require on off switching At this time it is understood our design would try for continuous closing of the end effector based on continuously increasing force however it might be necessary to implement a gripping sequence from a threshold force 113 3 3V FSR press to actuate aripper INVERTING INPUT 8 Figure 1 Top View DIP SO Package FFF Voutto microcontroller Analog input signal To drive gripper s
117. roller to the base motor Initial prototype success The third milestone of getting the same prototype performance through our metal robot arm took place March 25 when team member Taylor Jones connected a 118 motion sensor through the prototype Arduino mcu to drive a servo and rotate the end effector link Initial mpu 6050 sensor board success The fourth milestone of getting all the sensors and motors running through our control board simultaneously took place April 22 Complete control board SUCCESS The fifth milestone where the high performance game begins of coordinated performance of the robot arm linkages to the human operator s arm motion was initially attained on April 25 Qualitative system performance success The sixth milestone of getting our initial target of 1 second or less delay time from the human operator s arm to successful motion tracking response of the robot arm was partially obtained also on April 25 Initial quantitative system performance success This is the end of the build phase The seventh milestone was to achieve a smooth tracking motion and very short delay time between human arm motion and robot arm response of approximately 0 10 seconds Not attempted 9 2 Budget and Financing The initial budget estimate was 400 to 800 total The final budget is very close to 800 The project was completely self funded 9 3 Looking Toward EEL4915 and Back Our initial concern for eel4914 was a working des
118. rom the robot In order to accurately portray a human arm the robot should have at least six degrees of freedom a rotating and bending base a bending elbow a wrist that bends and rotates and an end effector capable of opening and closing The importance of having this many degrees of freedom is for the robot to be able to replicate every movement that is possible for a human arm to do This will result in the robot having six motors that will need to be controlled by the control board In order for the operators movements to be properly read sensors will be required to be worn on their arm A total of five sensors will be necessary in order to properly read the movements of the operators arm These sensors must be able to detect either movement on multiple axis or rotation depending on their location The elbow sensor and a wrist sensor will need to be able to detect rotation as they will correspond to joints that bend The forearm sensor and a second wrist sensor will need to detect movement along several axis in order to control motors that spin In order to control the motors and interpret the feedback from the sensors a control board is needed This control board will be responsible for reading the data sent from the sensors interpreting it and using it to send signals to the motors telling them what position to move to The control board must be able to connect to a computer through a USB connector and have room to handle all of the inputs
119. s the arm could even provide stable transport of an item held by the arm Accelerometers may be able to complete the task however this would require more resources to process the information and create a useful output Processing Sensor Data The data from the accelerometers will give their orientation due to gravity any acceleration due to movement and vibrations With a low pass filter most of the high frequency vibrations can be eliminated Care must be taken not to have the 76 bandwidth too small or the response to quick movements of the accelerometers will be sluggish and lead to errors in calculations This may be compensated for with measurements from the gyroscopes but will not be determined until the testing phase Each axis will have one output for each of the three axises measured The three measurements can be combined to produce a vector pointing towards gravity From this vector it is possible to calculate rotation of the accelerometer from a predefined orientation This will prove to be challenging to do on the operator because for every different user or for even the same user the sensors will be in a slightly different position and orientation than they were the time before To compensate for unique orientation each time the sensors are placed on the user a solution is to have the user will have to go through a setup process If the sensors are mounted on the outside of the arm between the elbow and shoulder on the out
120. s EEL4914 projects from 2006 DUCSS a DARPA autonomous vehicle sensor system and a 2009 project Luke s Hand an attempt at a human prosthetic robotic hand 19 References 1 Accessed Oct 22 2012 http www YouTube com watch v DINtsQYsT Q amp feature related No contact info on YouTube 2 Accessed Oct 22 2012 http www YouTube com watch v vqbNoALYVd4 amp feature related 3 Accessed Oct 24 2012 http www YouTube com watch v z3 6A4PBgmA No contact info on YouTube 3 2 GENERAL RESEARCH ON ROBOTICS GENERAL RESEARCH ON ROBOTICS as related to our project Because the Electrical Engineering program at UCF doesn t offer any undergraduate courses in Robotics or wireless communications it was determined appropriate content for this design project to include a section on robotics in general This author actually took the EGN3060 course Introduction To Robotics but it was neither mechanically nor electronically oriented it was computer science oriented programming in java of holonomic roomba round robots Motion planning and maze solving are somewhat advanced topics for an introductory course The PID stuff was easy though found it curious that embedded systems EEL4742 did not do any labs with mechanical actuators either no dc stepper or servo motor labs Robotics The definitions of robotics are numerous and varied ultimately they all deal with a labor saving machine that with increasing technological capabilit
121. side of the forearm and on the back of the hand each axis of the accelerometers can be moved into a position to experience 1g in three different positions of the arm To account for the rotation of the sensor of the forearm the wrist can be rotated to give the change in orientation The fact that there will be accelerometers and gyroscopes on the same PCB would allow the measurement of the distance the joint of rotation This would require more movements more setup time and may have the benefit of better interpretation of the intended movement particularly the desired extension of the robotic arm By pairing accelerometers and gyroscopes the signals can complement each other and help counter accumulated errors Accelerometers alone cannot maintain the correct position of the robotic arm The acceleration is discretized and will continually accrue Also the accelerometers cannot measure constant velocity so one a steady movement will seem like to separate movements to the accelerometer Gyroscopes will provide the desired speed of the robotic arm from which distance traveled can be measured but cannot be used for position because like the accelerometers the values are discretized and error will accumulate from one movement to the next The values for the paired accelerometers and gyroscopes will allow the error to be reset or at least maintain a maximum error The gyroscopes will also allow for accelerations from movements to be canceled out to keep
122. sources can be internal batteries or external ac to dc converted power sources For digital robots there must always be an electrical power supply Analog computing and robotics are not considered Sensors are the marvel of the twenty first century robotics ranging from laser range finding to micro electrical mechanical systems on a chip like gyroscopes angular motion detectors accelerometers linear motion detectors and magnetometers directional motion like a compass detectors Actuators Our project being on a human interactive robotic arm is really at the heart of industrial robotics Industrial robots have many shapes based on their functionality however a human arm like function is very common Our plastic robot arm uses revolute rotary joints driven by light weight dc motors and a 21 threaded drive on the motor shaft driving small plastic gear trains The metal arm has the gearing inside the servo motors cases Each servo motor has three connections positive and ground power connections from the power supply and a drive signal from the microcontroller Our robot arm is what is known as a serial robot which is contrasted with parallel robots Most industrial robots are equipped with serial technology where each axis is in line relative to the preceding one The parallel robot on the other hand has three or more prismatic or rotary axes which function parallel to one another Examples of parallel robots are Tricept
123. ssembly and to implement the final 6 1 design directly was a severe mistake Also using servos that did not have the robot arm manufacturer s specific bracket mounting compatibility probably was not a good idea Then non delivery from a vendor servos created a combined seven week delay in project progress The last month of the project was done on an as needed basis and testing was done purely on a go no go basis while building Fortunately component integrity held up well The sensor subsystem consists of three Invensense mpu 6050 6 axis 3 gyroscopic and 3 accelerometer gyro accelerometers Four 6050 s were acquired from Ebay and surface mount soldered onto custom printed circuit boards designed in Eagle and printed at 4pcb com Three sensor boards are mounted on Velcro straps and placed on the human operator s arm see photo section 10 2 System Construction A continuously variable FSR force sensitive resistor pressure sensor is used on the Velcro strap on the human operator s hand in a simple op amp voltage divider circuit to actuate the gripper end effector on the robot arm because of time constraints a simple open close button arrangement was used during the project demonstration An additional custom pcb was used to make the microcontroller unit featuring an Atmel ATxmega128A4U with two TWI two wire interface ports to connect the sensor boards 9 A table of prototype testing is in the section 8 0 Testing Checklist
124. st it relays to all the other devices now know as slaves the frequencies to use and the slaves all follow The second function makes sure that the devices take turns communicating in an ordered manor 5 5 4 3 Methods to connect microcontroller to Bluetooth There are many different Bluetooth devices available on the market and the majority are simple plug and play devices You can simply just connect one directly to your microcontroller by either an Rs232 serial interface a UART or a USB connection Buying a microcontroller that already has a built in serial interface and then connecting it to a Rs232 Bluetooth adaptor would be the easiest method 4 5 4 3 1 UART UART is an acronym for a Universal Asynchronous Receiver and Transmitter and is used for communication with serial input output devices Serial transmission reduces to cost and complexity of wiring at the expense of speed and this is a well desired trade off for a many applications UARTs provide serial data through asynchronization in two forms one being parallel to serial and the other serial to parallel data conversion for both 80 transmission and reception These functions are necessary for converting the serial data stream into parallel data that is required with digital systems Synchronization for the serial data stream is accomplished by adding start and stop bits to the transmit data to form a data character Data integrity is insured by attaching a parity bit to th
125. tem computing application is a form of Al 4 1 3 Simulation Simulation in robotics is generally simulating a mechanical robotic motion or device on a computer without having to make the actual physical device Since we do not have to make our robotic arm mechanically we do not intend to do any simulation However in 4915 we will attempt some system simulations in Matlab regarding the motional stability of our robot arm 4 1 4 Computer Programming Computer programming is the most relevant of all the technologies We do not have to make the mechanical robot arm s We do not have to design or manufacture any of the MEMS or IC chips used We will probably just use the sensors as they are from the on line robot shops We probably won t have to design or make any gearboxes as the robot arms either have the gearboxes included or any servo motors selected already have gearboxes built in What we 35 do have to do however after getting the basic electronics functioning is program a working and stable robot arm master slave mirror motion system If we succeed in our attempt our project will probably be over 90 programming How explain computer programming as a relevant technology to a robotics project Everything about robotics is getting some type of labor saving human intelligence into a machine whether a pick and place robot arm on an assembly line or Baxter co workin with the tunes on the mechanism to make the robot think is only comp
126. the first receive A solution to this issue is that each data word will be started with a start 82 bit The start bit is always identified by the space line level Because the line is in mark state when idle the start bit is easily recognized by the receiver Data bits Directly following the start bit the data bits are sent A bit value 1 causes the line to go in mark state the bit value O is represented by a space The least significant bit is always the first bit sent Parity bit A parity bit is used for error checking purposes The idea is to add an extra bit to the data word automatically The transmitter calculates the value of the bit depending on the information sent while the receiver performs the same calculation and verifies if the actual parity bit value relates to the calculated value Stop bits Suppose that the receiver has missed the start bit because of noise on the transmission line It started on the first following data bit with a space value This causes garbled date to reach the receiver A mechanism must be present to resynchronize the communication such a method is called framing Framing means that all the data bits and parity bit are contained in a frame of start and stop bits The period of time lying between the start and stop bits is a constant defined by the baud rate and number of data and parity bits The start bit has always space value the stop bit always mark value If the receiver detects a valu
127. the sensor sleeve power supply and the vertically mounted robot arm shown graphically in the following sections Chapter 7 Build Plan 7 1 Parts Acquisition for Prototype Enough parts have already been obtained to begin working during the break between terms on a prototype Parts already acquired include 1 L38GD20 3 axis gyro 1 Arduino Mega microcontroller board 1 DRV8833 Dual Motor Driver Carrier 1 TB6612FNG Motor Driver 1 FSR 1 5 inch square 1 female jumper cables and header pins 1 small breadboard 7 2 Prototyping The parts already acquired are sufficient to create a sensor microcontroller motor driver system to drive two motors of the robot arm at a time The prototype functioned well however completely different sensors were chosen and implemented for the metal arm Plastic arm prototype 92 7 3 Hardware Assembly As mentioned previously we have already successfully constructed an initially usable robot arm the OWI 535 Edge Our hardware assembly includes populating the printed circuit boards which were sent to be manufactured at 4pcb com and assembling the sub systems into the final system 6 axis sensor boards aE Sensor mpu 6050 board schematic 93 mpu 6050 sensor board pcb diagram Completed mpu 6050 sensor board with 4x4x1 mm gyro 94 Microcontroller 0 01 uF 10 uF ipa i 32 PORTE PAG a PER poe PA PBO PBI PB2 PBS GNOI
128. to rotate 4 71 5V 0 ov ims 20ms ij 5V n oo ov 1 5ms 20ms 5V 180 os em ov 2ms 20ms Fig 5 2 2 2 4 References 1 Accessed Nov 25 2012 http www arrickrobotics com motors html 2 Accessed Nov 25 2012 http openmoco org node 1 79 3 Accessed Nov 25 2012 http www robotshop com 4 Accessed April 28 2013 http flugleiter de wissen allgemein wissen servos wie funktioniert ein servo attachment servo signal 5 3 Sensor Subsystems 5 3 1 2C SERIAL COMMUNICATION C is a two wire bi directional communication technology for connecting integrated circuit chips to exchange data between the circuits The two wires are serial clock SCL and serial data SDA Bi directional means the device can output data and sense voltages on the line at the same time I C uses an open collector or open drain to generate digital data by a signal input to the base of the bipolar transistor draws the open collector transistor to ground and then a pull up resistor puts a high voltage on the collector if the base is open or the signal into the base is zero The data is clocked by the SCL input In the open drain 72 MOSFET technology the open drain is connected to ground if a high voltage is applied to the gate terminal generating logic O output and is open if low logic is applied A pull up resistor generates a logic 1 output if the drain is open The low state is considered active in open collector open
129. tp www idemployee id tue nl g w m rauterberg presentations hci history tsld089 htm 7 Accessed Dec 1 2012 http www rethinkrobotics com 8 Accessed Dec 1 2012 video screen captures from http www rethinkrobotics com index php support open source info rethinkrobotics com sent for permission to use 12_1 no response as of 12 5 9 Accessed Dec 1 2012 http www rethinkrobotics com index php support open source Section 3 1 Similar Projects In order to bring this project to life extensive research was done on similar projects Relevant ideas and designs were taken into consideration from current and past projects where robotic arms were controlled by similar mechanism discussed in the specifications of this report Although the general idea of the implementation for this project is understood the specifics of how to implement each individual piece were unclear The information gathered from the projects found allowed an insight into the design of the different components that make up this project From the sources insights were taken from both the innovations and the mistakes made by each The notes gathered from each project helped further the design process and lead to a more refined design in itself Some of the projects had a major financial backing and were very complex while others were simple proof of concepts done with spare parts The adaptation of these technologies will ultimately lead to a midpoint between the
130. trolled robotic walking device that enables a person with mobility impairment to stand up and walk 16 For Clarification cybernetics is defined as the theoretical study of communication and control processes in biological mechanical and electronic systems especially the comparison of these processes in biological and artificial systems 17 Programming 26 Referring to Baxter brings up the subject of programming Of course Baxter s and any other robots motions are programmed in some kind of central processing computing power however robots like Baxter claim to be application programmable by non technical people by direct manipulation of Baxter s arms walk through method and presumably voice interactive commands The user does not have to write any code or perhaps not even use a teach pendant push button interface 10 There are four basic methods of industrial robot programming 14 e Lead through in which the robot is placed in teach mode and moved through the various points in space and each point is recorded for playback at a later time e Walk through in which the robot is placed in teach mode and the manipulator is walked through the various points of the program and each point is recorded for later playback during operation e Plug in in which a prerecorded program is uploaded into the robot s control processor e Computer programming in which programs that are written off line on a computer are transferred to the
131. unstable An idealized teleoperator causes a tool telerobot to move in space matching exactly the motions of an operator All forces imposed on the tool should be accurately reflected back to the operator 3 We might have to put sensors on the robot arm to generate feedback control signals to determine that the robot arm is tracking the human arm motion properly 59 Control box Motors on robot arm Sensors on arm probably a powered and respond powered and microcontroller to control signals from actively sending board receiving controller board signals sensor signals and outputting motor control signals Fig 5 0 5 Initial open loop control scenario suitable to test basic functionality of the sensors and motors and control box followed by ane box Motors on robot arm Sensors on arm nani den powered and respond powered and microcontroller ED to control signals from actively sending board receiving controller board signals sensor signals and outputting motor a control signals Fig 11 f Add feedback from motion sensors on robot arm to confirm accurate motion tracking Fig 5 0 6 A control algorithm is needed to identify the position of the robot linkages at any instant In traditional robotics a coordinate system is defined and the position of the end effector the gripper is located in an absolute position relative to the base of the motion which in our case is t
132. urement error is known and b if a measurand is supposed to be represented by a unique true quantity value or a Set of true quantity values of negligible range in which case the measurement error is not known NOTE 2 Measurement error should not be confused with production error or mistake From what have read so far the difficulty in our project appears to be that the MEMS gyroscopes have a changing reference data value and require constant re calibration of the measured quantity value minus a reference quantity value for the zero position reference Returning to the industrial website and merrily cutting and pasting something that can understand finds 2 From Wikipedia Accuracy is how closely a robot can reach a commanded position When the absolute position of the robot is measured and compared to the commanded position the error is a measure of accuracy Accuracy can be improved with external sensing for example a vision system or human operator or Infra Red 105 Repeatability precision is how well the robot will return to a programmed position This is not the same as accuracy It may be that when told to go to a certain X Y Z position that it gets only to within 1 mm of that position This would be its accuracy which may be improved by calibration But if that position is taught into controller memory and each time it is sent there it returns to within 0 1mm of the taught position then the repeatability will
133. uter programming While there is still some analog machine robotics around 99 of current robotics uses digital intelligence In fact a web search for analog robotics turns up not much more than BEAM is an acronym suggesting the basic factors to consider when designing robots biology electronics aesthetics and mechanics 1 BEAM is also mostly theoretical research and so are the few other analog robotics mentioned What computer programming will our robot use For the prototype to achieve first motion we used the Arduino language with the Arduino mega microcontroller The Arduino language is based on C C It links against AVR Libc and allows the use of any of its functions see its user manual for details 2 However the microprocessor that we use for our own control board the ATmegai28 which is also the microprocessor on the Arduino microcontroller can also be programmed in assembly language 8 At this point in time we intend to do most of our programming in C C however that may change as the project evolves References 1 Accessed Dec 5 2012 Analog Robotics Chaos at the Core of Intelligence by Marcos Kuhnshttp www2 hesston edu Physics RobotMK report html 2 Accessed Dec 5 2012 http Arduino cc en Reference HomePage 3 Accessed Dec 5 2012 AVR Studio 4 and ATmega128 A Beginner s Guide http eecs oregonstate edu education docs mega1 28 starterguide pdf 4 2 Possible Components Som
134. uts These pins will produce a PWM Pulse Width Modulation a digital output that will be what tells the servo motors how far to turn and in what direction based on the length of the signal There are also 10 sensors connectors each connected to their own pin on the microcontroller These sensors are connected to the microcontroller as inputs This allows the microcontroller to know if the operator has changed position and will know what output to provide to which motors The inputs are connected to pins that are capable of AD conversion which allow the microcontroller to measure the input from the sensors and produce an exact position for output to the motors The AD conversion may not be needed depending on whether the sensors themselves produce a digital or analog output If the sensors produce a digital output then they may be moved to a different pin if needed The Schematic of the circuitry is shown in the figure below 62 Wireless unit ait Psat Psat sat sant fs ii bedl bedl B 4 fe 4 Figure 5 1 1 Schematic for robot arm controller 5 1 1 Robot Arm Kinematics Kinematics is the study of the geometry of motion of linkages like the shoulder to elbow and elbow to wrist and wrist to end effector links in our robot arm Since we are using a pre designed and manufactured mechanical arm the OWI 535 Robot Arm Edge we don t have to do the dynamic analysis of the forces and stresses
135. utton and uses an ATmega32u4 microcontroller The Arduino Leonardo is one of the first models that Arduino produced that didn t require a second microcontroller to handle communications with a USB This feature is relevant to the project because in making a choice for a microcontroller one that needs no other component in order to use a USB makes programming the microcontroller much easier once it is set in the PCB board In order for Arduino Leonardo to control motors it must have a motor controller like the Arduino Motor Shield attached to it The motor controller takes directions from the control board and with an external power supply capable of powering the motors gives directions to the motors Below is a picture of the schematic for the Arduino Leonardo Arduino LEONARDO 5V AUTO SELECTOR pi t H la ti SA Figure 4 3 1 Arduino Leonardo schematic A second control board looked at for this project was Polou s Baby Orangutan robot controller shown in figure 4 3 2 The Baby Orangutan has 18 1 O lines 8 of which can be used for analog a built in motor driver and uses an ATmega328P microcontroller Measuring only 1 20 x0 70 the Baby Orangutan is built to be used in space constrained areas This control board has a built in motor driver to handle the control of the motor s so unlike the Ardiuno board an extra motor control board is not needed This reduces the amount of space the control board requires but also
136. well funded projects and the cheaper ones 3 1 1 Luke s Hand One relevant project worth mentioning is a past senior design project This project was done by group 6 of the fall 2009 semester The project was called Luke s Hand and the goal was to create a prosthetic limb that could mimic the movement of a human hand and be controlled a number of ways A picture of this project can be seen in figure 3 1 1 The project s goal was to have the hand controlled by three methods through a computer program an RC controller a glove that the user wore or switches on the control board The project ultimately ended with only the glove interface and switch interface being implemented due to various reasons The glove interface consisted of a cloth glove that contained a flex sensor in each finger As the user would move their hand the flex sensors would send a signal to the microcontroller telling it how far each finger was bent The microcontroller then told the motors that controlled the robot fingers how far to move The robotic hand also had sensors on it in order to determine if objects were in its hand and whether or not they were slipping The sensors used included touch sensors and a potentiometer The touch sensors were used to provide feedback to the microcontroller to let it know that the hand was currently holding something The potentiometer was used to detect if the object being held was slipping at all If the object was slipping the
137. y seem a perfect match By Tom Green http www roboticsbusinessreview com article rio_tintos_3 6b _bid_to_marry_mi ning_to_robotics P2 6 Accessed Dec 4 2012 by UCF student id Robotic Surgery Equipment Manufacturing in the US Market Research Report http www ibisworld com industry robotic surgery equipment manufacturing html IBISWorld s Robotic Surgery Equipment Manufacturing market research report provides the latest industry statistics and industry trends allowing you to identify the products and customers driving revenue growth and profitability The industry report identifies the leading companies and offers strategic industry analysis of the key factors influencing the market 7 Accessed Dec 5 2012 Foxconn gears up to build industrial robots world industrial robot population to double http Awww gizmag com foxconn gears up to build industrial robots 20389 picture 146587 3 3 1 FUTURE OF ROBOTICS As observed in the previous section the future of robotics technologically 33 is increasingly ubiquitous interactivity with people specifically more human like work capabilities of Baxter and his progeny The trend is described as robotic devices that cooperate with people 1 The business future of robotics is also looking quite optimistic Consumer robot sales are expected to reach 15 Billion dollars by 2015 1 There is conjecture that in the near future robots could be accounting for 50

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