[Classified*]

I can't say much about using gyros to stay straight, I know we tried to use them before, but there was too much drift to be useful, However I was not personally involved in that so I'm not sure.

On the other hand, we have had a lot of success with encoders and PID. We used them all through the season with great success. Wheel slip was definitely not a problem (we had treads this year) even on slippery tile flooring our robot had no problems. We had a major problem with our treads being misaligned. After lots of hard driver practice on our practice bot this became a problem. The robot would drift to one side even though both encoders were reading the same value because of the bent tread.

Also, if you do end up using encoders, it is very important to make sure the slop in both gearboxes is forward, especially if your encoders aren't on the output shaft (they should never be anywhere else).

If you would like our encoder PID code, I have it in both Java and Labview, and I would be happy to share.

On another note, are you trying to shoot a high goal using just encoders? I wouldn't recommend this, the goal is very small for that. It is best to use vision tracking to find the retro reflective tape on the goals. If you use Labview I can help you with this. If you don't have vision, Going for a low goal auto is a better bet. Better to get 5 points most of the time than get 10 some of the time and lose the ball the rest of the time. Encoders are more than adequate for a low goal auto.

I hope this helps