Transcript Self-Guided Wheelchair - Iowa State University
Student Members:
Margaret Shangle Vee Shinatrakool Tara Spoden John Volkens Brian Yauk
Faculty Advisor:
Dr. Nicola Elia
Client:
National Instruments
Self-Guided Wheelchair
Design Review Presentation
Agenda
Presentation Overview
Introduction Functional Requirements General Solution Detailed Design Summary
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
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
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
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
General Solution
End Product Description
Functionality
LabVIEW Embedded controlled operation User-selectable starting and ending points Path calculation Obstacle detection Obstacle avoidance Location recognition Speed control (forward, reverse, stop) Turn control with 5% accuracy
Total
Relative Importance
35% 5% 10% 10% 5% 10% 15% 10%
100%
Evaluation Score
100% 95% 90% 90% 80% 50% 100% 100%
Resultant Score
35% 4.75% 9% 9% 4% 5% 15% 10%
91.75%
General Solution
End Product Description
Inputs
Starting position/final destination Current location Distance to obstacles Magnetic orientation Gyroscope orientation
Processing
Calculate path from start to end Determine critical obstacles Recalculate path from current location Left/right wheel control for intended speed/turn
Outputs
Left/right wheel control Sensor stimuli Input information (interfacing) Location information (debugging)
General Solution
End Product Description
24V Battery 5Vreg 9Vreg 12Vreg Motor Control Box RFID Reader Sonar Array (x13) RS232 Trigger [0:12] Echo [0:12] Compass ADC Gyroscope ADC Controller LCD Display [0:7] [0:7] USB DB15 Left/Right 5.9V ± 0.9V
ADC ADC 5.9V ± 0.9V
Forward/Reverse Joystick Keypad USB
General Solution
End Product Description
5 4 3 2 6 7 8 1 9 10
1 Controller 2 LCD 3 Keypad 4 Compass 5 Gyroscope 6 Modified joystick 7 Motor Control Box 8 Batteries 9 Sonar 10 RFID Reader
Detailed Design
Overview
Controller & Software
- John
Sensors • • Ranging Modules Orientation Motor Control Localization Power Management User Interface
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
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…
Detailed Design
Controller & Software
Detailed Design
Controller & Software
Detailed Design
Overview
Controller & Software Sensors • •
- Brian
Ranging Modules Orientation Motor Control Localization Power Management User Interface
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
Detailed Design
Ranging Modules
Mounting • Front: ○ Obstacle Detection ○ Mapping • Sides: ○ Wall Tracking ○ Hallway Detection • Rear: ○ Backing up
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 °
Detailed Design
Orientation Sensors
ADXRS150 Angular Rate Sensor • Uses: ○ Gyroscope ○ Measures rate of turning • Operation: ○ Detects up to 150 °/s
Detailed Design
Overview
Controller & Software Sensors • • Ranging Modules Orientation Motor Control
- Tara
Localization Power Management User Interface
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 / 2 n ≈ 7mV
Detailed Design
Motor Control
Detailed Design
Overview
Controller & Software Sensors • • Ranging Modules Orientation Motor Control Localization
- Margaret
Power Management User Interface
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
Detailed Design
Localization
Mounting • Reader/Antenna ○ ○ Bottom of chair 4” reading range • Tags ○ Floor ○ Span critical intersections, starting points/destinations Connection ○ RS232 -> USB
Detailed Design
Overview
Controller & Software Sensors • • Ranging Modules Orientation Motor Control Localization Power Management User Interface
Detailed Design
Power Management
Power requirements: • 24VDC ○ Wheelchair • 12VDC ○ Mini-Itx Controller* • 9VDC ○ RFID Reader • • 5VDC ○ Ultrasonic Sonar ○ Gyroscope ○ Compass USB (5VDC) ○ Keypad ○ LCD Testing will rely on individual power supplies Not a priority for prototype design
Detailed Design
Power Management
Individual systems: • Wheelchair, controller, RFID reader 5VDC system:
Detailed Design
Overview
Controller & Software Sensors • • Ranging Modules Orientation Motor Control Localization Power Management User Interface
- Vee
Detailed Design
User Interface
Mini-box picoLCD • • • Uses: ○ Gather inputs ○ Display selected and current locations ○ Debugging Operation: ○ 2x20 character display Connection: ○ USB
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
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
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