Self-Guided Wheelchair Design Review Presentation

1. Self-Guided WheelchairDesign Review Presentation Student Members: Margaret Shangle Vee Shinatrakool Tara Spoden John Volkens Brian Yauk Faculty Advisor: Dr. Nicola Elia Client: National Instruments

2. Agenda Presentation Overview • Introduction • Functional Requirements • General Solution • Detailed Design • Summary

3. Introduction Project Description • Self-guided wheelchair • Capable of autonomously moving through environment while avoiding any obstacles • Selectable starting points/final destinations • Based on motorized wheelchair • Programmed with LabVIEW Embedded 8.2 • Sponsored by National Instruments

4. Definitions Project Terminology LabVIEW Embedded…. graphical programming language developed by National Instruments for implementation on OEM hardware RF……………………….. (radio frequency) frequency that lies in the range within which radio waves may be transmitted, from about 10 kilohertz per second to about 300,000 megahertz. Transponder…………… radio transmitter-receiver activated for transmission by reception of a predetermined signal. An RF reader/transmitter sends a signal via radio waves in order to detect transponders designed to read that reader’s particular frequency signal. VI………………………… (virtual instrument) file containing subroutines or subfunctions created in LabVIEW

5. Functional Requirements Operating Environment • Medical hospital setting • Operation on a single floor level • Free of stairs or similar large drop-offs • Common hospital floor type • Tile • Hardwood • Short carpet

6. Functional Requirements Intended Users and Uses • Primary User • Provides location information for the system input • Shape recognition and basic literacy • Medical staff or guardian • Secondary User • Passenger that will be transported • Able to maintain a seated position within the confines of the chair dimensions • Patient

7. General Solution End Product Description

8. Inputs Processing Outputs General Solution End Product Description Starting position/final destination Current location Distance to obstacles Magnetic orientation Gyroscope orientation Calculate path from start to end Determine critical obstacles Recalculate path from current location Left/right wheel control for intended speed/turn Left/right wheel control Sensor stimuli Input information (interfacing) Location information (debugging)

9. 24V Battery Motor Control Box 5Vreg 9Vreg 12Vreg DB15 Left/Right 5.9V ± 0.9V RS232 RFID Reader [0:7] Trigger [0:12] ADC Joystick Controller Sonar Array (x13) ADC [0:7] 5.9V ± 0.9V Forward/Reverse Echo [0:12] USB Keypad Compass ADC USB Gyroscope ADC LCD Display General Solution End Product Description

10. 1 2 3 4 5 9 6 7 10 8 General Solution End Product Description 1 Controller 2 LCD3 Keypad 4 Compass 5 Gyroscope 6 Modified joystick 7 Motor Control Box 8 Batteries 9 Sonar 10 RFID Reader

11. Detailed Design Overview • Controller & Software - John • Sensors • Ranging Modules • Orientation • Motor Control • Localization • Power Management • User Interface

12. Detailed Design Controller & Software • VIA EPIA-EN12000EG Mini-ITX • 1.2GHz VIA C7 Fanless Processor • DDR2 533 SDRAM (up to 1 GB) • Full range I/O including USB & Serial • Full PC capabilities • XP and LabVIEW Embedded • Expandable • Multiple Peripheral I/O

13. Detailed Design Controller & Software • Operating System • Windows XP Embedded • RFID Reader • Software • LabVIEW Embedded • All calculations, algorithms • VIs for I/O to sensors • Program Flow…

14. Detailed Design Controller & Software

15. Detailed Design Controller & Software

16. Detailed Design Overview • Controller & Software • Sensors - Brian • Ranging Modules • Orientation • Motor Control • Localization • Power Management • User Interface

17. Detailed Design Ranging Modules • Ultrasonic SRF04 Sonar Sensors • Uses: • Navigation • Obstacle detection • Operation: • Sends out a sonar pulse • Calculates distance to nearest object based on reflection time • 55° Angular Resolution

18. Detailed Design Ranging Modules • Mounting • Front: • Obstacle Detection • Mapping • Sides: • Wall Tracking • Hallway Detection • Rear: • Backing up

19. Detailed Design Orientation Sensors • Devantech R117 Magnetic Compass • Uses: • Find heading relative to Earth’s magnetic field • Operation: • Pulse width modulated • 1-37ms • Accuracy: 3-4°

20. Detailed Design Orientation Sensors • ADXRS150 Angular Rate Sensor • Uses: • Gyroscope • Measures rate of turning • Operation: • Detects up to 150°/s

21. Detailed Design Overview • Controller & Software • Sensors • Ranging Modules • Orientation • Motor Control - Tara • Localization • Power Management • User Interface

22. Detailed Design Motor Control • Operation based on potentiometers • Forward / Reverse • Right / Left • 5.9V ± 0.9V DC signal • D/A converters • Output from controller • 8-bits per speed, direction • Step Size = Span / 2n≈ 7mV

23. Detailed Design Motor Control

24. Detailed Design Overview • Controller & Software • Sensors • Ranging Modules • Orientation • Motor Control • Localization - Margaret • Power Management • User Interface

25. Detailed Design Localization • APSX RW-310 RFID Reader and Transponders • Uses: • Identify current location relative to onboard map • Identify start/end point • Operation: • High Freq (13.56MHz) • Sends RF signal to transponders/tags • Passive tags return ID

26. Detailed Design Localization • Mounting • Reader/Antenna • Bottom of chair • 4” reading range • Tags • Floor • Span critical intersections, starting points/destinations • Connection • RS232 -> USB

27. Detailed Design Overview • Controller & Software • Sensors • Ranging Modules • Orientation • Motor Control • Localization • Power Management • User Interface

28. 24VDC Wheelchair 12VDC Mini-Itx Controller* 9VDC RFID Reader 5VDC Ultrasonic Sonar Gyroscope Compass USB (5VDC) Keypad LCD Detailed Design Power Management • Power requirements: • Testing will rely on individual power supplies • Not a priority for prototype design

29. Detailed Design Power Management • Individual systems: • Wheelchair, controller, RFID reader • 5VDC system:

30. Detailed Design Overview • Controller & Software • Sensors • Ranging Modules • Orientation • Motor Control • Localization • Power Management • User Interface - Vee

31. Detailed Design User Interface • Mini-box picoLCD • Uses: • Gather inputs • Display selected and current locations • Debugging • Operation: • 2x20 character display • Connection: • USB

32. Detailed Design User Interface • Targus USB Numeric Keypad • Uses: • Gather inputs • Select starting location and final destination • Initiate travel • Emergency stop • Operation: • 19-key • Connection: • USB

33. Other Considerations • Economic/Environmental • RoHS compliant controller, wheelchair non-compliant (1991) • Localization system comparatively inexpensive • Social/Political/Ethical • N/A • Health/Safety • System not designed for environments with large drop-offs • Obstacle avoidance critical to passenger safety • Manufacturability/Sustainability • Prototype design – not designed for manufacture • Proof of concept only

34. Summary • LabVIEW Embedded controlled operation • Path calculation • Obstacle avoidance algorithm • User-selectable starting and ending points • Keypad, LCD • Obstacle detection • Sonar • Location recognition • RFID reader and tags • Motor speed control • D/A Converter • Turn control • Gyroscope, compass

35. Questions ? ? ?