Autonomous using encoders

[Joe Hershberger]

Originally Posted by Eagle Master

Dave everything is working correctly as far as the encoders go. I am looking to find out how other teams keep the robot going straight over long distances. Like you mentioned, an active feedback of the difference between the counts of the 2 sides. Does anyone have a sample equation?

Kevin,
The way we approached this a few years back was to implement an observer on the optical encoders that tracked the current state of the robot (i.e. x/y position and orientation) We then used a PID control loop using our state as the feedback, not the raw encoder values. This allowed us to see that we drove away from the line we intended to follow and turn back toward it.

I can explain how the observer was modeled if that sounds like something you'd be interested in. The model is very simple and the implementation was straightforward.

Cheers!
-Joe