PADS Paraplegic Assisted Driving System Aaron Broome Robert Graham Lamar Turnbull Tylor Palumbo Erick Moton Georgia Institute of Technology ECE 4007 Moore Fall 2010

Project Overview  Autonomous speed control system Provide paraplegics with an alternative means of transportation through the use of the following: 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 Objectives Autonomous 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 Goals Goals Proposed Specifications Actual Specifications Units Response Time for Matlab to recognize signs < 1 sec Refresh rate of speed calculation < 10.5sec Time required to completely stop vehicle from maximum speed < 7 sec Time required to adjust speed for new speed zone ≤ 5 sec Achieve accurate speed for speed zone ± 2 mph Accurate reading of zone colors (Red (STOP), Blue (5 mph), Black (10 mph) Yellow (13mph)) ± 20N/ARGB

Prototype Design Overview Laptop 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 Function Zone Reaction Times: Real-time road tests

Testing Results Goals Desired Specifications Tested ValuesUnits Response Time for USB cam to recognize signs <10.22Sec Time required to completely stop vehicle from different speeds <7 5mph Sec 10mph mph Time required to adjust speed for new speed zone ≤ 5 5mph-10mph – 14.4 Sec 5mph-13mph – mph-13mph – mph-5mph – mph-5mph – mph-10mph – 8.52 Achieve accurate speed for speed zone ± 2 5mph – 5.35mph Mph 10mph – 9.99mph 13mph – 12.84mph

Procedure Flow Diagram Counter/Timer0 Speed Sensor Pulse (Input Port Signal) LCD Display RS232 Send/Receive Subroutine H-Bridge (Output Port Signal) Webcam Color Detection Speed Calculator RS232 Send/Receive Subroutine Speed/Color Combined Response Subroutine Matlab Operations PIC18F452 Operations Pushbutton (Reset)

Hall Effect Speed Sensor  Speed Calculation

Matlab Object Recognition

Problems & Solutions Speed Calculation via Timer/Counter Refresh rate for reading input pulses/sec Color Sensing and Object Recognition RGB threshold for various lighting conditions Number of Magnets Mounted to Wheel Quality 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 Analysis Part NameCost CMUcam2$109 Actuators$180 Magnetic Sensor $20 Microcontroller$205 Actuator Housing $60 Power Supply$80 Total$654  Project Budget:  Project Budget: $440  Amount spent to date:  Amount spent to date: $  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: Questions