ME 224-Final Project

1. ME 224-Final Project Jim Lovsin Erica Morales Dan Sheehan Josh Widzer

2. Overview • Introduction • Robot Activities • Gyroscope Activities • Path Programming • Results • Future Work • Conclusion

3. Objectives • To design and implement an experiment to realize the control of a commercially available robot • To enhance our knowledge of LabView, data acquisition, feedback control, and MEMS sensing

4. The Goal • To create a robot which utilizes gyroscopic feedback control to navigate the predetermined path shown below. 6 53.1° 90° 3 4 5 36.9°

5. The Equipment • A computer with LabVIEW and a data acquisition card • A gyroscope sensor (ADXRS150EB) from Analog Devices • A Boe-Bot Robot Kit (www.parallax.com, #28132)

6. Robot Activities • Servo Centering • Assembly • Basic Paths

7. Servo Centering • Since the servos are not preadjusted in the factory, it is necessary to adjust the servos so that they are stopped when a 1.5 ms pulse is used

8. Assembly • The Boe-Bot came unassembled so some assembly was required • Followed the instructions provided

9. Basic Paths • Forward • Both wheels rotating in the same direction at the same speed • Right turn • Both wheels rotating at the same speed but the left wheel goes forward and the right wheel goes backward • Left turn • Both wheels rotating at the same speed but the right wheel goes forward and the left wheel goes backward

10. Gyroscope Familiarity • Operating Principles • Coriolis Acceleration • Fc = 2mv x Ω • Capacitive Sensing • Self-Test • Calibration • First Attempt • Second Attempt Vibrating MEMS Gyroscope Ref: K. Elliot, P. Gupta, K. Reed, and R. Rodriguez “Micromachined Vibrating Gyroscopes: Design and Fabrication” (2002) Northwestern University Mechanical Engineering 381: Introduction to Microelectromechanical Systems Final Project

11. Followed Self-Test Procedure from Chip Data Sheet Power supply, Multimeter, and Oscilloscope RATEOUT Initially 2.5 V Applied 4.6 V to pin 10. RATEOUT 3.2 V Applied 4.6 V to pin 11. RATEOUT 1.81 V Self-Test Schematic of ADXRS150EB Satisfactory Self-Test Ref: Analog Devices, ±1500/s Single Chip Yaw Rate Gyro with Signal Conditioning, ADXRS150EB Data Sheet http://www.analog.com/UploadedFiles/Data_Sheets/778386516ADXRS150 B.pdf

12. First Attempt Correlate Angle to Voltage Signal Second Attempt Correlate Angular Rate to Voltage Signal LabVIEW to acquire and collect the data Excel to analyze the data Calibration Block Diagram of LabVIEW Calibration Program

13. Calibration First Attempt Experiment: Turned Boe-Bot by hand to a known angle for a given time Correlate Angle to Voltage Θi = B0 + B1 Σ Vi Δt Where: B0 and B1 are parameters from OLS • Angles • 90 and 180 (deg) • Problems • Accurate Positioning and Timing • Numerical Integration R2 = 0.04

14. Calibration Second Attempt Experiment: Turned Boe-Bot at a known angular rate for a given time Correlate Angular Rate to Voltage d/dt (Θi) = B0 + B1Vi Where: B0 and B1 are parameters from OLS • Angular Rate • 2.06, 3.05, 1.78 (rad/s) • Problems • Accurate Positioning and Timing • Numerical Integration R2 = 0.64

15. Path following programs • Basic Stamp Program • Directly creates the PWM signal needed for the servos • LabView Program • Reads & analyzes readings from gyroscope, controls basic stamp program

16. Basic Stamp Program Forright: PULSOUT 13, 600 PULSOUT 12, 800 PAUSE 18 GOTO Main Forleft: PULSOUT 13, 700 PULSOUT 12, 950 PAUSE 18 GOTO Main Right: PULSOUT 13, 775 PULSOUT 12, 775 PAUSE 18 GOTO Main Left: PULSOUT 13, 725 PULSOUT 12, 725 PAUSE 18 GOTO Main ' Robotics with the Boe-Bot - PathProgram.bs2 ' Closed loop path control for the Boe-Bot. ' {$STAMP BS2} ' Stamp directive. ' {$PBASIC 2.5} ' PBASIC directive. DEBUG "Program Running!" '-----------------[Variables]-------------------- INPUT 0 INPUT 1 INPUT 2 INPUT 3 DO Main: IF ( IN0 = 1 ) THEN Sto IF ( IN1 = 1 ) THEN Forward IF ( IN2 = 1 ) THEN Right IF ( IN3 = 1 ) THEN Left LOOP END Sto: PULSOUT 13, 750 PULSOUT 12, 750 PAUSE 18 GOTO Main Forward: IF ( IN2 = 1 ) THEN Forright IF ( IN3 = 1 ) THEN Forleft PULSOUT 13, 700 PULSOUT 12, 800 PAUSE 18 GOTO Main

17. LabView Program 1 8 2 • There are three types of steps: • Stopped (0,9) • Straight line (1,3,5,7) • Turning (2,4,6,8) • Nine total steps 9 6 180 53.1 90 7 3 5 36.9 4 143.1

18. LabView Program Front Panel Stop Step

19. LabView Program Turning Step Step 8: 180 degrees CCW

20. Read Accumulated Voltage Zero? No Yes Greater than Zero? No Yes Forward Forright Forleft LabView Program Straight Path Step

21. Path Demonstration

22. Reliability Testing • Performed ten trials to see accuracy of Boe-Bot • Measured x and y distance from starting point and endpoint • Recorded angles robot made using LabVIEW

23. Results of Reliability Testing Deviation from Starting Point: Angle Results:

24. Future Works • Create large deviation correction functionality. • Closed loop control of distance. • Use encoders on servo wheels. • Use LabVIEW Realtime to improve performance over Windows. • Use wireless 802.11g or bluetooth protocol to remove cable from system. • Parallax has kits for sale.

25. Conclusion • Successfully completed the task of programming the Boe-Bot to execute a path • Enhanced our knowledge of LabVIEW, Basic Stamp, data acquisition, feedback control, and MEMS sensing

26. Questions?