Download - PADS Paraplegic Assisted Driving System
PADSParaplegic Assisted Driving System
Aaron BroomeRobert GrahamLamar TurnbullTylor Palumbo
Erick Moton
Georgia Institute of TechnologyECE 4007 Moore
Fall 2010
Project Overview Autonomous speed control system
Provide paraplegics with an alternative means of transportation through the use of the following:○ Linear Actuator controlled acceleration/braking○ Updated speed and related information display ○ LED display○ Accurate speed calculation○ 4-color recognition (Red, green, blue, black)○ Manual override switch for emergency shutdown and
reset Equipment Cost: $654
Technical ObjectivesAutonomous Speed Control
Use object recognition to detect 3 speed zones and stop sign
○ Matlab RGB color detection
Calculate speed and compare with latest detected sign
○ Measure revolutions/sec from PIC timer and counter ○ Compare with RGB values obtained from Matlab
Control gas/brake pedal to adjust to desired speed
○ High/low output logic from PIC sent to H-bridge based on color and speed
Project GoalsGoals
Proposed Specifications
Actual
Specifications Units
Response Time for Matlab to recognize signs < 1 < 1 sec
Refresh rate of speed calculation < 1 0.5 sec
Time required to completely stop vehicle from maximum speed
< 7 < 7 sec
Time required to adjust speed for new speed zone ≤ 5 ≤ 5 sec
Achieve accurate speed for speed zone ± 2 ± 2 mph
Accurate reading of zone colors (Red (STOP), Blue (5 mph), Black (10 mph) Yellow (13mph))
± 20 N/A RGB
Prototype Design OverviewLaptop w/ USB camera
& Matlab
Hall Effect Speed Sensor
4” and 6” Linear Actuators
Golf Cart
Qwikflash (PIC18F452) Development Board
Prototype Design Overview
Linear Actuators
Qwikflash Development Board
H-Bridge
Hall Effect Speed Sensor
Hardware Block Diagram
Hall Effect Speed Sensor
Laptop with USB Camera Serial Connection
Dual H-Bridge
4/6” Linear Actuators
12V Sealed Lead Acid Battery
Qwikflash Board
Linear Actuator Installation
Dimensions: 20”x16”16.5”
Prototype Design & Description
Prototype currently works as desired in each speed zone. Desired specifications hit or miss
Tests:Color Recognition Time: Matlab Timing FunctionZone Reaction Times: Real-time road tests
Testing ResultsGoals Desired
Specifications Tested Values Units
Response Time for USB cam to recognize signs <1 0.22 Sec
Time required to completely stop vehicle from different
speeds<7
5mph - 5.86Sec10mph - 6.70
13mph - 7.82
Time required to adjust speed for new speed zone ≤ 5
5mph-10mph – 14.4
Sec5mph-13mph – 17.8310mph-13mph – 8.9410mph-5mph – 17.6713mph-5mph – 15.09 13mph-10mph – 8.52
Achieve accurate speed for speed zone ± 2
5mph – 5.35mphMph10mph – 9.99mph
13mph – 12.84mph
Procedure Flow Diagram
Counter/Timer0 Speed Sensor Pulse (Input Port Signal)
LCD DisplayRS232 Send/Receive
Subroutine
H-Bridge (Output Port Signal)
Webcam Color Detection
Speed Calculator
RS232 Send/Receive Subroutine
Speed/Color Combined Response
Subroutine
Matlab OperationsPIC18F452 Operations
Pushbutton (Reset)
Hall Effect Speed Sensor Speed Calculation
Matlab Object Recognition
Problems & SolutionsSpeed Calculation via Timer/Counter
Refresh rate for reading input pulses/sec
Color Sensing and Object RecognitionRGB threshold for various lighting conditions
Number of Magnets Mounted to WheelQuality of sample used to calculate speed
Linear Actuator Response Timing
.5 seconds used as refresh in order to keep speed updated at a regular rate
RGB value threshold was eliminated due to lack of time
8 strips of magnets were attached to wheel to increase accuracy of speed calculation
Linear actuator set to extend and/or retract for one second every response period
Budget AnalysisPart Name CostCMUcam2 $109
Actuators $180
Magnetic Sensor
$20
Microcontroller $205
Actuator Housing
$60
Power Supply $80
Total $654
Project Budget: $440
Amount spent to date: $439.79
Microcontroller provided by Georgia Tech Savannah
Future Work The PADS prototype
system can be continued by future ECE students with additional work that could consist of the following: Implementation of LIDAR
for object avoidance Autonomous control of
the steering wheel GPS-assisted route
navigation
Additional information located on project website: http://www.tinyurl.com/gtsavseniordesign
Questions