Tom and Jerry

1. EEL-5666 – Intelligent Machines Design Lab Tom and Jerry By: Nicholas Johnson & Joshua Hartman

2. Overview • Overall Function • Tom’s Design • Jerry’s Design • Special Sensor – RF Link • Conclusions • Possible Improvements • Questions EEL-5666: Intelligent Machines Design Lab

3. Overall Function • Jerry and Tom simulate a Predator / Prey Model. • Jerry is the prey and has prey behaviors such as wandering and grazing. • Tom is the predator and searches for Jerry. • When Tom detects Jerry he will try to capture Jerry who tries to run away. EEL-5666: Intelligent Machines Design Lab

4. Tom EEL-5666: Intelligent Machines Design Lab

5. Platform • MAVRIC-IIB Development board • Wood • Cardboard part stands • Black duct tape. • Black duct tape. • More black duct tape. EEL-5666: Intelligent Machines Design Lab

6. Locomotion • GHM-03 Spur Gearhead Motor • TPIC0107B-based motor driver • These motors are fast EEL-5666: Intelligent Machines Design Lab

7. Obstacle Avoidance • 3 Devantech SRF05 • Use fuzzy-logic ideas to define obstacles as close, far, or in between • Very rarely hit obstacles EEL-5666: Intelligent Machines Design Lab

8. Searching for Jerry • Futaba S148 • Panasonic PNA4611 Infrared Photo IC • Servo rotates from -45o, -22.5o, 0o, 22.5o, 45o • At each location, reads A/D and detects if value<200. If so, Jerry is detected! EEL-5666: Intelligent Machines Design Lab

9. Searching for Jerry II • IR detection not so easy: • Must use ADC to read photo IC output • Vout goes low upon detection • Must have receiver highly shielded to give directional output EEL-5666: Intelligent Machines Design Lab

10. Jerry EEL-5666: Intelligent Machines Design Lab

11. Platform • Material: Wood • Cut using the T-Tech • Small, Compact Design • Had to be smaller than Tom • Limited Space • Difficult to fit all the electronics • Addition of unforeseen pieces problematic EEL-5666: Intelligent Machines Design Lab

12. Actuation • 2 Tamiya 70168 Double Gearboxes • 114.7:1 Gear Ratio • 4 wheels total • Driven by TPIC0108B PWM H-Bridge • Wheels on either side function independently • Each side driven by 1 Motor Driver • Servo Motor to turn “Tom Detector” EEL-5666: Intelligent Machines Design Lab

13. Sensors • Bump Switches • 2 Front, 2 Back • Maxbotix Ultrasonic Rangers • 2 Front, 1 Back • IR Emitter / Detector (Close Range) • 56.8 KHz IR Detector • 315 MHz RF Receiver • 434 MHz RF Transmitter EEL-5666: Intelligent Machines Design Lab

14. Sonar • Provides analog interface • The higher the voltage the further away the object. • Start time of each sonar can be controlled. • Readings obtained 50ms after start. • Sequentially check each sonar • If returned value below threshold then obstacle detected. EEL-5666: Intelligent Machines Design Lab

15. Jerry’s Design – Close IR • Analog output • Brighter areas give lower voltages. • If returned value above threshold then obstacle detected. EEL-5666: Intelligent Machines Design Lab

16. Jerry’s Design - Behaviors • Wandering • Randomly moves around avoiding obstacles. • If “food” (black spot) is detected it will switch to grazing behavior. • Frequently looks for Tom. • If Tom is detected it will immediately switch to running behavior. EEL-5666: Intelligent Machines Design Lab

17. Jerry’s Design - Behaviors • Grazing • Holds on top of food for a preset time. • Will slowly move across the food until passes it completely. • Infrequently looks for Tom. • If Tom is detected it will switch to running behavior. EEL-5666: Intelligent Machines Design Lab

18. Jerry’s Design - Behaviors • Running • Moves away from Tom as fast as possible. • Turns frequently in order to escape Tom. • If caught, will stop and wait to be reset. • If preset time has gone without being caught will return to wandering behavior. EEL-5666: Intelligent Machines Design Lab

19. Special Sensor - RF Link • www.sparkfun.com • Tom: • 434MHz Receiver • 315MHz Transmitter • Jerry: • 315MHz Receiver • 434MHz Transmitter • Links used to communicate robot status to determine exhibited behaviors. EEL-5666: Intelligent Machines Design Lab

20. RF Link Difficulties • Receiver designed to “lock on” to signal. Therefore, sender must transmit alternating bits for receiver to lock onto the baud rate. • Receiver will increase gain until it finds a detectable signal. Therefore, it will output garbage if the transmitter is not sending. EEL-5666: Intelligent Machines Design Lab

21. RF Link difficulties • Receiver must “synchronize” with transmitter. If a transmission looks like: 0 0 0 1 0 1 1 0 1 0 1 0…, the USART has no real way to recognize the start of a transmission. Over a wired link, the line is usually high and is pulled low using the start bit. This is not the case in RF. • Finally, the receiver has a band-pass filter centered at its tuned frequency. When the robots get far enough away, this is washed out by the local transmitter. EEL-5666: Intelligent Machines Design Lab

22. RF Link Algorithm • Use interrupts to continually send 0xAA, the locking code. • When want to transmit, send out 0xFF to resynchronize the link • Finally, send out data. EEL-5666: Intelligent Machines Design Lab

23. Conclusions • Both robots successfully avoid obstacles. • Wireless successfully incorporated. • Tom successfully detects Jerry and will head towards him. EEL-5666: Intelligent Machines Design Lab

24. Possible Improvements • More reliable detection method. • IR not always reliable and dependent on environment. EEL-5666: Intelligent Machines Design Lab

25. Questions? • Acknowledgements • Dr. A. A. Arroyo • Dr. E. M. Schwartz • Julio Suarez • Adam Barnett • Thomas McDonley • Jason Taylor EEL-5666: Intelligent Machines Design Lab