May07-15 Self-Guided Wheelchair

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May07-15 Self-Guided Wheelchair

• Industrial Review Panel Presentation

25 April 2007
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Introduction
May07-15 Team

• Faculty Advisor
• Dr. Nicola Elia
• Client
• National Instruments

• Student Members
• Brennen Beavers
• Margaret Shangle
• Vee Shinatrakool
• Tara Spoden
• John Volkens
• Brian Yauk

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Acknowledgments
Special thanks to

• National Instruments
• Michael Phillips
• Indianola Home Medical

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Agenda

• Project Overview
• Project Activities
• Project Definition
• Research Activities
• Subsystem Activities
• Approach
• Design Implementation
• Testing
• Resources Schedule
• Closing Summary

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Basic System Diagram
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1. LCD Keypad
2. Microcontroller
3. Custom motor control
4. Motor control box
5. Batteries
6. Photodetector arrays
7. Sonar array
8. IR sensors

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List of Definitions
Important Terminology

• LabVIEW Embedded graphical programming language
  developed byNational Instruments for
  implementation on OEMhardware
• VI.. (virtual instrument) file
  containing subroutines orsubfunctions created in
  LabVIEW
• DAC or D/A... (digital to analog converter)
  electronic device that isused to convert digital
  signals into analog signals
• GPIO... (general purpose input/output)
  microcontroller port which can be configured for
  input and/or output
• Photodetector...... sensor which uses the
  photoelectric effect to convert light into an
  electrical signal
• Sonar.. (sound navigation and ranging)
  method of detecting and locating objects using
  echolocation/sound waves

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Project Overview
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Problem Statement
General Solution Approach

• Problem Statement
• Hospital staff is often burdened by transport of
  patients confined to wheelchairs
• Independence of patient limited by schedule and
  convenience of staff
• Prototype Solution
• Retrofitted wheelchair
• Autonomous, track-guided navigation
• Microprocessor-controlled operation usingLabVIEW
  Embedded 8.2
• Obstacle drop-off detection

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Operating Environment

• Indoor setting with typical hospital floor type
  such as tile, hardwood or short carpet
• Single-level floorplan, not designed for elevator
  transport

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Intended Users and Uses

• Intended User
• Primary hospital staff
• Secondary disabled wheelchair passenger
• Intended Uses
• Patient transport between hospital departments
  and exam rooms
• Proof-of-concept of indoor localization
• Demonstration of LabVIEW Embedded 8.2 target
  capabilities

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Assumptions Limitations

• Assumptions
• Typical hallway environments
• Obstacle and drop-off detection in forward
  direction
• Single, predefined destination
• Floor easily equipped with grayscale path
• Limitations
• Motorized wheelchair provided
• All hardware secured to wheelchair frame
• Unobstructed mobility passenger accommodation
• LabVIEW Embedded 8.2
• 1150 budget

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End Product

• Conceptual prototype, not designed for commercial
  reproduction
• LabVIEW Embedded-controlled autonomous operation
• Track-guided navigation
• Obstacle and drop-off detection

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Present Accomplishments
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Project Definition(Vee)
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Redefinition
Original Definition Revised Definition
Calculate path from user-specified starting point to the user-specified ending point Calculate path from user-specified starting point to the user-specified ending point
Travel from beacon to beacon Travel along track on predetermined path
Detect both moving and stationary obstacles Detect both moving and stationary obstacles
Navigate around stationary obstacles Discontinue movement in event of obstacle
Traverse reasonably shallow ramps or other such gradual changes in plain elevation Traverse reasonably shallow ramps or other such gradual changes in plain elevation
Detect floor drop-offs Discontinue movement in event of drop-off
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Research Activities

• Technological research
• Existing autonomous transport
• Prescription delivery system
• Lego Mindstorms
• Roomba
• Indoor localization
• Distance sensors
• Process
• LabVIEW embedded development

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Controller Connection Diagram
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Subsystem Activities

• User Interface
• Approach
• Design Implementation
• Microcontroller
• Obstacle Detection
• Localization
• Software
• Motor Control

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Approach
User Interface

• Selection
• HC-Keypad
• HC-LCD

• Other Considerations
• Touchscreen
• Expensive
• Complex integration

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Design Implementation
User Interface

• Predefined list of locations
• Character string ID
• Error checking
• LCD Keypad
• User prompt and input
• Connection
• LCD/keypad port
• Implementation Status
• Simulation complete

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Subsystem Activities

• User Interface
• Microcontroller
• Approach
• Design Implementation
• Obstacle Detection
• Localization
• Software
• Motor Control

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Approach
Microcontroller

• Selection
• CMD565 Evaluation Board
• PowerPC LabVIEW target

• Considerations
• Handyboard
• Limited I/O
• Mini-ITX
• Unported LabVIEW target

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Design Implementation
Microcontroller

• CMD565
• Months of debug (with technical support)
• Download often unresponsive and unreliable
• Identified as probable hardware fault
• PB0555
• Substitute to verify system w/o LabVIEW
• Unported LabVIEW target
• Usability verified with C code
• Time unavailable to implement system control

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Subsystem Activities

• User Interface
• Microcontroller
• Obstacle Detection
• Approach
• Design Implementation
• Localization
• Software
• Motor Control

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Approach
Obstacle Detection

• Other Considerations
• Laser sensor
• Very Expensive
• Mechanical bumpers
• No Advanced Warning

• Selection
• Obstacle detection
• MaxSonar EZ1
• Drop-off detection
• Infrared GP2D15

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Design
Obstacle Detection

• Sonar
• 1 forward, 2 angled on sides
• Increased detection area
• False reading protection
• Infrared
• 1 above each front wheel
• Connection
• Sonar direct to micro ADC
• Infrared direct to micro GPIO
• Implementation Status
• Simulation complete
• Sonar Firmware failure

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Subsystem Activities

• User Interface
• Microcontroller
• Obstacle Detection
• Localization
• Approach
• Design Implementation
• Software
• Motor Control

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Approach
Localization

• Selection
• Original fixed beacon
• RFID
• Redefinition
• off-board track
• Lynxmotion Tracker Sensor

• Other Considerations
• Dead reckoning
• No error correction
• Fixed beacons
• Complex integration
• Ultrasonic/optical imaging
• Very complex integration

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Design
Localization

• Photodetectors
• 2 rows (path waypoint)
• Gray tape indicates intersections/destinations
• Mounting
• Low profile
• Front of wheelchair
• Connection
• Direct to micro GPIO
• Implementation Status
• Simulation complete
• Mounted

Black line
Grey line
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Subsystem Activities

• User Interface
• Microcontroller
• Obstacle Detection
• Localization
• Software
• Approach
• Design Implementation
• Motor Control

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Approach
Software

• Selection
• LabVIEW Embedded Version 8.2(project requirement)

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Design Implementation
Software

• Original
• Sequential flow
• Implemented
• Threading
• Implementation status
• Full system simulation complete
• Embedded portions (memory access) not yet
  implemented

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Subsystem Activities

• User Interface
• Microcontroller
• Obstacle Detection
• Localization
• Software
• Motor Control
• Approach
• Design Implementation

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Approach
Motor Control

• Selection
• Joystick modification
• Offset Voltage
• Custom R-2R DAC circuit

• Other Considerations
• Signal creation
• No documentation available
• Complex signal
• Off-the-shelf DAC IC

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Design Implementation
Motor Control

• R-2R ladder DAC
• 8 bits speed
• 8 bits direction
• Summing
• Joystick input
• /- 0.9V offset

• Implementation
• Mounted in project box
• Manual control toggle
• Potentiometers for system calibration

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Testing
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Testing
Component Test type Description Testing Status
Keypad LCD Component Input recognition Verified complete
Functionality Simple LabVIEW program interface Unverified
Micro Component Basic operation Verified as intermittent
Functionality LabVIEW embedded I/O operation Verified as intermittent
Sensors Component Basic operation Verified complete
Sonar, IR, photodetectors Functionality Detection limitations (distance, motion, color, etc) Verified complete
Software Module (VI) Individual VI functions Verified complete
Functionality Full system simulation with LabVIEW simulated inputs Verified complete
Motor Control Component Basic operation Verified complete
Functionality Complete system with battery power Verified complete
Full system Operational Full system hardware software Unverified
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Resources Schedule
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Resources
Personal Effort (Hours)
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Resources
Financial Requirements
Item Cost
Sensors
Devantech R117 Magnetic Compass (x1) 52.00
MaxSonar EZ1 Sensor (x5) 124.75
Infrared GP2D15 Sensor (x1) 12.50
Photodetector Tracker Sensors (x6) 139.65
Motor Control
OpAmps (x10) 12.66
IC Sockets (x2) 6.54
Circuit Boards (x2) 3.58
Resistors/Potentiometers (x60) 11.45
Wires, Solder -- 3.59
Other
CMD565 Evaluation Board (x1) --
HC Keypad LCD (x1) 60.00
DC/DC 12V Power Supply (x1) 39.95
LabVIEW Embedded 8.2 --
Total 466.67
Materials Cost
Poster (x1) 52.00 52.00
Motorized Wheelchair (x5) 124.75 124.75
Other Resources
Mounting Equipment (x1) 12.50 12.50
Wiring and Misc. Equipment (x6) 139.65 139.65
Subtotal 651.57 651.57
Labor Hours Hours Cost
Brennen Beavers 101.5 1,065.75 1,065.75
Margaret Shangel 139 1,354.50 1,354.50
Vee Shinatrakool 189 1984.50 1984.50
Tara Spoden 213.5 2,241.75 2,241.75
John Volkens 197.5 2,073.75 2,073.75
Brian Yauk 151.5 1,590.75 1,590.75
Subtotal 10,311.00 10,311.00
Total 10,962.57 10,962.57

• Donated by National Instruments
  Previously donated to Senior Design by Invacare

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Schedule
Task Schedule
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Schedule
Reporting Milestones
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Closing Materials(Tara)
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Project Evaluation
Functionality Relative Importance Evaluation Score Resultant Score Resultant Score
LabVIEW Embedded-controlled operation 35 50 50 17.5
Track following ability 15 75 75 11.25
Location/intersection recognition 10 75 75 7.5
Path calculation 10 90 90 9
Obstacle detection 10 50 50 5
Drop-off detection 5 85 85 8.5
User-selectable starting ending points 5 90 90 4.5
Speed control (forward, reverse, stop) 5 100 100 5
Turn control 5 100 100 5
Total 100 73.25
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Commercialization

• Not designed for commercialization
• Goals
• Proof-of-concept for indoor localization
• Evaluation of usability of LabVIEW Embedded

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Lessons Learned

• What went well
• Donated parts
• Subsystem specialists
• Early-established technical support
• What did not go well
• Delayed redefinition of project
• LabVIEW training on data acquisition

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Lessons Learned

• Technical knowledge gained
• LabVIEW software development
• C node for register access
• Method of determining the source of a failure
• Indoor localization
• RFID, Photodetectors vs. photointerrupters
• Non-technical knowledge gained
• Estimating required resources
• Adaptation to schedule changes
• Best form of communication
• Effort ! Success

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Risk Management

• Anticipated risks
• Equipment damage (motor control box)
• Defective hardware (ultrasonic sensors, micro)
• Team member inexperience (LabVIEW)
• Unanticipated risks
• Non-functioning wheelchair
• LabVIEW installation issues
• Project redefinition
• Changes due to risks
• Intermediate milestones
• Reorganization into multiple-person sub-teams

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Recommendations for Additional Work

• Improved localization phase
• Dead reckoning
• Fixed beacons
• Optical or ultrasonic imaging
• Obstacle avoidance phase
• Recalculation of path around obstacles
• Commercialization phase
• Update wheelchair
• Clean form factor
• User-programmable mapping
• Users manual

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Closing Summary

• Main goals
• Proof-of-concept for indoor localization
• Expense of versatile design
• Distance limitations of RFID
• Reliability issues with photodetectors
• Evaluation of usability of LabVIEW Embedded
• Not an intuitive tool for embedded programming
• Simple integration for software debugging

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Demonstration
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Questions???