GPS Robot Navigation Critical Design Review

1. GPS Robot NavigationCritical Design Review Chris Foley, Kris Horn, Richard Neil Pittman, Michael Willis

2. Need • Unmanned and automated systems • Can protect human lives • Can provide convenience and safety • Military • Warfare • Dangerous locations • Surveillance • Civilian • Everyday navigation

3. Goal and Objectives • Goal: Develop a GPS guided system that will successfully navigate to a series of pre-defined coordinates. • Objectives: • Stable, sturdy system • Able to start at any location • Follow a pre-defined path • Be able to avoid obstacles

4. Litterature • www.oopic.com • www.junun.org/MarkIII • The Devantech SRF04 Ultrasonic Range Finder • Optical EC Encoder Kit Documentation

5. Design Contraints • Budget • Time • Technical Scope

6. Alternative Solutions • Compass or not ? • Reprogram using a laptop, or a keypad ? • Control the car by tapping into the servos or by using the remote control circuit ?

8. Final Design Breakdown • Mark III Board with OOPic provides control • Sonar Configuration provides obstacle detection • GPS and Compass provide navigation information

9. Final Design Breakdown • User interface through serial connection to computer • LCD provides user feedback • Battery and voltage regulation provide power to components

10. Subsystems • Object Detection System • Velocity Control System • Navigation System

11. Object Detection • Sonar: -- Efficient outdoors -- Far range • Devantech SRF04 Ultrasonic range finder. • Range 3” – 10’

12. SRF04 Controller Interface • 4 pins: Power, Ground, input Trigger, and output Echo. • Trigger 0→1: Sonar emits a ping and the Echo → 1. • Echo → 0 ping returned.

13. SRF04 Algorithm • Time length Echo is high. • Sea level sound travels 2’/1.8 mSec. • Obj. Distance ft. = (time sec.) * (1/.0018)

14. Sonar Configuration

15. Velocity Control • Manual speed control • Servo controls motor voltage. • Optical Encoder measure angular velocity.

16. Optical Encoder • E3 optical encoder US Digital Corp. • 3 output channels A, B, and Index used read quadrature track. • A leads B, rotating CW. B leads A, rotating CCW. • Index: 1 pulse / rev.

17. Velocity Control (cont.)

18. Navigation System • Inputs: destination coordinates, current GPS coordinates, compass heading, steering commands (from collision avoidance system) • Outputs: steering control commands, speed control commands, coordinate reading

19. Navigation System • Function: control the movement of the robot along a path • Uses algorithm programmed into the OOPic to make path calculations based on current inputs • Will always choose best path from current location

20. Validation and Testing Procedures • Test individual components(speed control, steering, sonar, lcd, gps, compass, navigation algorithm) • Integrate and test piece by piece • Test system as a whole

21. Schedule

22. Division of Labor and Responsibilities • The GPS unit and Navigation Algorithm: Chris and Michael • Compass, Sonar and Servos: Kris and Neil

23. Economic Analysis • Economical Viability • Total cost per unit: $352.50 • Sustainability • Components from various vendors • Manufacturability • FCC compliant GPS • Production yield dependant on number of workers

24. Societal, Safety, and Environmental Analysis • Use the robot for locations that are unsafe for humans or difficult to get to. • Exhibit normal care and safety measures that apply when using electronic equipment • Carefully plan path so as not to harm environment