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Bob Odegard

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Bob Odegard
Web Site: www.barb-n-bob.com

Rover

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Type: 2-wheel differential steering type
Purpose: A development platform to develop various types of behavior software and hardware.
Controller:
- 386-25MHZ (2mb RAM, 2 serial ports, MS-DOS BIOS, Embedded MS-DOS)
- (5) SX Scenix micro controller (running at 4Mhz)
  - Keyboard Handler
  - (2) PWM Motor control Handler
  - Sonar Handler
  - Motor Encoder Handler
Software Development Environment: Windows 95 SDK's, Borland C++ 4.52 (16 Bit) and SX Tech assembler.
Sensors:
- Sonar and IR proximity (on a front mounted R/C servo)
- Touch sensors:
  - (Front array) made by encapsulating a wire and a brass plate, inside a 1/4"rubber tube mounted in front of a 1" diameter semi-rigid tube, mounted on the front edge of the robot.
  - (Back array) made of 1/32" looped wire.
- Optical encoders: built into the DC Motors
- Keyboard: a 5x4 button keyboard used to instruct Rover in various modes.
Output Devices:
- Voice Synthesizer - V860 connected via the printer port.
- RS232 port - Connected to a Palm Pilot for output debugging information.
- Mini SSC II - RS232 to R/C Servo signal generator
Actuators: Two 24V DC motors with encoders from ABC Electronic.
Power source: 12V 42AH deep cycle battery used in handicapped motor scooters.
Construction history: I was looking for a system/platform that I could try out different AI systems for controlling robots with the goal of creating bigger robots that can work in the home (Lets face it , I want a robot to do house work!). I knew that I needed to learn more about mechanical and electronic systems, so what better way than to build a system that can grow. Soon into the design it became obvious that I needed a big enough platform to handle the various components (386 processors, output and input modules) without being to cramped. I settled on a 2 foot diameter round robot (Home Depot had pre-cut plywood). I started out with just one layer but knew I could add more layers as my need increased. Currently I have two layers and I'm thinking of a third layer. The nice thing about multiple layers is you can attach components on both sides of the layer, giving you lots of room for devices, cabling and maintenance room.
Most of the electronics run at 5 volts and I've found that a 12 to 5 volt DC-to-DC converter is the most power effective means to provide power. However, it's still recommended to use big capacitors to stabilize the output 5 volt power. Rover currently uses 3 amps for all the electronics and an 1 to 1.5 amps for the motors.
Operational description: Rover has different modes of operation:
1. Idle Mode - Continuously scan the Sonar/IR sensors to determine distances to object in front of Rover, monitor battery voltage , keyboard and leash input.
2. Cable Leash Mode - Monitor leash inputs and respond to command inputs.
3. Roam Mode - Continuously moving forward to roam a room, but monitoring Sonar/IR to avoid running into objects.
4. IR Beacon Following Mode - With the user holding an IR beacon (modulated at 38khz), Rover's tracking head will lock on to the beacon and turn the robot into the beacon and follow the user as they walk down a hall way like a little lost puppy!
Future Enhancements/Plans: I'm considering adding video image processing (for my earlier project EDYE) give Rover binocular vision to detect objects in front of him. And possibly to start looking for specific types of objects (this is very far reaching).
Status: Software and Hardware are on-going developments (the more I do, the more I want to add!).