1. Aggressive Chasing Car
ECE 445 Senior Design
Team 38
Hai Chi, Zhe Ji
Prof. Carney
TA: Mustafa Mukadam

2. Introduction
Our goal is to design a linkage system among a running car, a chasing car and a camera on the ceiling.
The chasing car chases the running car using an aggressive pursuit algorithm. It runs in two modes: sensor mode and camera mode.

3. Features Sensor based detection Image based detection
Image recognition and processing
Trajectory calculation and estimation
Motor driving
Wireless Communication

4. High level Block Diagram

5. Actual Photos

6. Microcontroller Unit Requirement Power supply is stable at 9±1V
On camera mode, XBee is connected successfully, motor is well controlled
On sensor mode, decide direction from sensor inputs
Verification
Measured by multimeter
Print out the commands from both sides.
Print out motor direction in the console and compare with actual behavior.

7. Data Flow in Sensor Mode

8. Data Flow in Camera Mode

9. MCU Code

10. Wireless Communication
Xbee
Requirement
Connection between IPC and MCU is 100% successful.
Power source is stable at 3.1±0.3V
Verification
Print out the input and output on both sides
Measure the voltage using multimeter.

11. XBee Photos
IPC side MCU side

12. XBee Code

13. Motor Control Requirement Speed is stable at 0.35±0.05m/s
Turning mechanics can be controlled by MCU
Verification
It goes 1.8m within 5 seconds. We measured with measuring tape and timer.
Print out the command and check with the actual behavior.

14. Motor Control
H-Bridge
Direction control

15. Step down voltage converter from 9V to 6V
Motor Control
Step down voltage converter from 9V to 6V

16. Sensor Detection LV-MaxSonar-EZ4 Requirement
Power supply is stable at 5±0.1V
Distance accuracy is within 3cm.
Field of view is 120 degrees.
Verification
Measured by multimeter
Print out distances and compare to the readings from measuring tape
Measured by protractor

17. Samples

18. 673.5mV
69inch
125.0mV
13inch

19. Sensor Code

20. Image Processing Requirement Power supply is stable at 19V
Filter out the background and preserve car’s object
Calculate the coordinates and turning direction
Verification
Charged from outlet
Print out the picture processed and verify by visual observation
Print out the turning command and compare with the actual behavior

21. Environment
Eclipse
Java
OpenCV

22. IPC Code

24. Calculation
Slope : K r ≈ Y r1 − Y r2 X r1 − X r2 ≈ Y r3 − Y r2 X r3 − X r2
Time difference: Δt = (X − X r3 ) 2 + (Y − Y r3 ) 2 V r = (X − X c3 ) (Y − Y r3 ) 2 V c
Angle difference: Δα = arctan( K c ′ ) −arctan(K c )

25. Sample Tests

26. Total Costs Item Name Unit Cost ($) Quantity Total Cost ($)
Logitech c270 web camera 30 1
LV-Maxsensor-EZ4 5
150
Laptop
300
Toy Cars 2 60
Arduino Mega 2560 59
9V Battery
XBee 25 50
Resistors
0.1
0.5
PNP switches 4
Total
666.5

27. Failures
The view range of the camera is very limited. This is unexpected and not included in the Design Review.
The delay in camera mode is about 0.3 – 0.4s, which is not tolerable in real time chasing.
The sensors are sensitive to any objects. They cannot tell which is the running car.
Due to the delay from the camera mode, we cannot find a proper algorithm for MCU to switch between modes.

28. Future Works Find a better camera to solve the view range problem
Carry out a decent algorithm for sensors to separate moving objects and still objects
Object dodging algorithm
Find a way to minimize the delay in camera mode
Implement the mode switching algorithm

29. Thank you!
Professor Carney
Mustafa Mukadam
Electronic parts shop

30. Questions?