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Sunday, 9 December 2007

Stage One Build Complete..

When I started out on this venture, the different products I had looked at and ordered, collectively formed an image of what the final robot would look like. I'm really pleased to have gotten this far, and have achieved what I had originally set out to build.

For your pleasure, below are photos of the initial Stage One prototype build.

There have been a number of changes from previous photos.
1) Four wheel drive, almost ;) - As an experiment I added a second dual axis gearbox and motors. Piggy-backing the driving of these motors from the single Pololu motor controller. I also tried this with just the gearboxes and no motors. It works suprisingly well in a straight line, but cannot turn to save it's life. With the weight of the Robot and low torque of the motors it just couldn't get enough drive to turn. Lots of stalling (on smooth and rough surfaces) meant the thermal cut-off in the motor controller to kick in.
2) VC21RB1 - I've added into the VC21 COG stack the Robot Controller (VC21RB1). And mounted the stack on another Pololu round robot chassis base. Space was getting really limited on previous versions, but I now have a mid-deck to mount anything (particularly power supplies).

This initial prototype build has taught me loads. And as predicted the tiny Pololu motor controller and Tamiya gearboxes and motors are really straining under the weight. I'm not throwing away the motors and gearboxes just yet though. I'm waiting on Virtual Cogs to release some example code for the VC21RB1 controller, and am ready to hook that up and test it out. Then in the new year it's onto the second prototype stage of changing the chassis to a track based system (probably the Robotics Connection Level 1 Traxster Robot Kit).

As far of what is working. All parts are working seperately. The CMUCam3 is connected and working with the Pololu motor controller (controlled via a laptop). The VC21 stack is working fine, but not tried connecting this up to the CMUCam3 yet. I need to get underway with VC21 COG development (particularly the I2C, UART, and LCD driver software) before going further with hooking up that final sub-system of this robot.

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