I don't have much experience in this sort of thing, but if that's the only goal of the project I'd probably just try fixed axles with multiple wheels spaced close together on each one (say 4-6?), with good-traction tires, front-wheel drive from a single motor. Slight slip on one tire would have very little effect because there are another 3-5 tires on the same axle to keep it in check.

That may sound like an insane idea but it's worth consideration? Maybe

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Good riddance, ETO .

 

i know im a little late, but just wanted to mention that a heading hold gyro should work nicely in this application.

 

I was going to say that I'd go with the trailing tail wheel sensor, and dare say many would use a PIC to control everything but you could almost certainly do it with an ordinary analog system as well. However this system would probably fall foul of the rules becuase you are tracking the relative floor movement.

Alternatives:
GPS is expensive and quite frankly overkill for the budgets of almost all the teams.
Standing the trailing wheel system on it's head , a gyroscope to hold the heading.
Inertial sensors? to track X/Y movement, common in the RC helicopter world..
Hall, compass sensors.. again had little to do with them accuracy may be an issue.

At the end of the day it's a point and pray test of how well the bot is set up, the ability to detect wheel slippage would be useful but it makes for a much more complicated robot.



Is it scored soley on accuracy over the length of the course or is the time taken a factor as well? Visions of robotic dragsters hurtling out of control makes for a great spectator sport..