PT 5000 Pooja Rao Ted Tomporowski December 7, 2004.
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Transcript of PT 5000 Pooja Rao Ted Tomporowski December 7, 2004.
PT 5000
Pooja Rao
Ted Tomporowski
December 7, 2004
Functional Overview
To create an autonomous vehicle that is capable of:
Following a reflective tape path from start to finish Stopping at specifically marked checkpoints and waiting for user
recognition to continue Display of number of checkpoints reached Diverting from the path to avoid obstacles
Specifications
Will follow reflective tape path when unobstructed.
Will detect obstacles within 2’, and divert from the path in an optimal manner to avoid them
Will stop at designated checkpoints Lightweight Will not be affected by ambient light Minimum runtime of 10 minutes
Restrictions
Maximum number of checkpoints: 3 Obstacle minimum size: 8” wide x 12” long x 2” high Path cannot turn more sharply than the turning radius
of the car Obstacles cannot be placed such that they are very
close to the track but not on it Checkpoints cannot be obstructed, and must be on
straight portions of the track
Components
Servo Motor DC Motor Sharp GP2D12: distance-measuring sensor Fairchild QRB1134: phototransistor reflective
object sensor HCS12
Steering
The vehicle will have front wheel steering, controlled by a servo motor.
DC Motor
PWM ports on the HCS12 in conjunction with H-Bridges will be used to control the DC motor and the speed of the vehicle.
A higher voltage will be supplied to the motor when the vehicle is turning to counteract the effects of added friction, thus maintaining the vehicle’s speed.
GP2D12 – IR Analog Distance Sensor
The Sharp GP2D12 is a general-purpose type distance-measuring sensor, which consists of a position sensitive detector and an infrared emitting diode and
signal processing circuit This sensor has a 2” beam
width
Distance Sensor Output
QRB1134 – Opto-reflector
The QRB1134 consists of an infrared emitting diode and an NPN silicon phototransistor. The phototransistor responds to radiation from the emitting diode only when a reflective object passes within its field of view.
Datasheet optimum range
4 millimeters
Port Diagram
Design & User Interface
Two buttons are present– Start Button: this button is
toggled to either start the vehicle initially, or to tell it to continue when it is halted at a checkpoint
– Reset Button: this button is used to reset the vehicle to its start state
Two sets of LED’s are present– The blue LED’s represent the
checkpoints that have been reached
– The Obstacle light is lit when the car sees an obstacle and goes into obstacle avoidance mode, and the Error light is lit if the vehicle finds itself in an unknown state
Dimensions & Blind Spots
Track Following
4 opto-reflectors will be used for track following.
3 are used for forward navigation, and the 4th is used while navigating backwards.
Using 3 sensors allows for quick error detection and correction, as well as efficient turning.
Obstacle Avoidance
Obstacle Avoidance Algorithm
Move forward
Obstacle DetectedNo
Clear on Right
Yes
Yes
No
Turn car until left side sensor sees the obstacle at 12”
Move Forward
Distance < 9” Turn Car Rightyes
Distance > 15”
no
Turn Car Leftno yes
Clear on LeftTurn car until right side sensor
sees the obstacle at 12”
Move Forward
Distance < 9”
Distance > 15”
no
Turn Car Left
Turn Car Right
yes
yes
Yes
Back upNo
Checkpoints
Checkpoints will be denoted by a special pattern in the tape that will be recognized when the vehicle travels over it.
The vehicle will halt at each checkpoint until it receives the user prompt to continue.
An LED will be lit (and remain lit) at each checkpoint, so that at the end of the course, it can be seen how many of the checkpoints were reached.
Track Patterns
Sample Track Layout
Power Consumption
Due to lengthy power-up times of the sensors (especially the distance sensors), all sensors will be powered constantly
Component Current (mA) Voltage (V) Power (W)
HCS12 45 5 .225
Servo Motor 500 5 2.5
DC Motor 1000 9.6 9.6
Opto-Reflectors (4) 35 * 4 = 140 5 .700
IR Distance Sensors (6) 35 * 6 = 210 5 1.05
IC’s/LED’s ? ? ?
Total 1895 + 14.075 +
Testing Strategy
Test each sensor for performance Code review for each major software
component Component testing after SW/HW integration System testing
Testing Strategy (cont’d)
Test vehicle on various track setups Test vehicle under varying light conditions Test various types of obstacles (shapes) Run many iterations of tests to work out
performance bugs
Difficulties
Algorithm to allow vehicle to realign itself with the track after avoiding an obstacle
Reverse navigation
Progress
Project Milestone Expected Completion Date
Design Review Preparation 12-7-2004
Buy and test all other needed components 12-12-2004
Have the vehicle built 1-3-2005
Have the code written and tested as much as possible without being interfaced with the car
1-3-2005
Website Development 2-8-2005
The car can successfully navigate an obstacle free path and recognize stations
1-13-2005
The car can navigate the path and avoid standard obstacles that does not require backing up
1-20-2005
The car can navigate the path and avoid all obstacles including backing up to avoid them
1-27-2005
Testing 2-8-2005
Report Written 2-8-2005
Completed Website 2-8-2005
Poster Completed 2-10-2005
Cost
Part Actual Cost Our Cost Vendor
Vehicle $43.29 $43.29 Toys R’ Us
Colored LEDs ( many ) $10.00 $10.00 Digi-Key
Distance sensors (7) $70.00 $70.00 Online Vendor
Opto-reflectors (6) $40.00 $40 Fairchild
Battery Pack (5V) $15.00 $0 Toys R’ Us
Battery Charger $10.00 $0 Toys R’ Us
HC12 $100.00 $0 CE Department
Servo Motor $5.00 $0 CE Department
Reflective tape (2) $5.00 $5.00 Lowe’s
IC’s $5.00 $5.00 CE Department
Voltage Regulators(4) $4.00 $4.00 Radio Shack
Steering Components $30.00 $30.00 Dan’s Crafts and Things
Miscellaneous Circuit Components $50.00 $50.00 Radio Shack
Miscellaneous $25.00 $25.00 Lowe’s
Total $412.29 $282.29
Questions?