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

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.

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

High level Block Diagram

Actual Photos

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.

Data Flow in Sensor Mode

Data Flow in Camera Mode

MCU Code

Wireless Communication Xbee 802.15.4 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.

XBee Photos IPC side MCU side

XBee Code

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.

Motor Control H-Bridge Direction control

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

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

Samples

673.5mV 69inch 125.0mV 13inch

Sensor Code

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

Environment Eclipse Java OpenCV

IPC Code

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 ) 2 + (Y − Y r3 ) 2 V c Angle difference: Δα = arctan( K c ′ ) −arctan(K c )

Sample Tests

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 802.15.4 25 50 Resistors 0.1 0.5 PNP switches 4 Total   666.5

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.

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

Thank you! Professor Carney Mustafa Mukadam Electronic parts shop

Questions?