GPS Robot Navigation Critical Design Review Chris Foley, Kris Horn, Richard Neil Pittman, Michael Willis

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

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

Litterature The Devantech SRF04 Ultrasonic Range Finder Optical EC Encoder Kit Documentation

Design Contraints Budget Time Technical Scope

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 ?

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

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

Subsystems Object Detection System Velocity Control System Navigation System

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

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.

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

Sonar Configuration

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

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.

Velocity Control (cont.)

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

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

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

Schedule

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

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

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