Encoders for Auto Driving

[geomapguy]

We are trying to program our auto mode for our robot to move a certain distance. We understand how to read the encoder and do the math.

The hard part is having the robot take those and drive. Would we use a PID or something similar? Obviously we'd want it to start to slow down near the end so it can be more precise.

We're coding in LabVIEW.

Thanks

[seg9585]

Yes, you would use a PID controller to be the most accurate. If you would rather keep things simple and less time consuming (at the cost of a little error), then using just proportional drive power as a function of distance to desired target (plus a bias to account for your deadband -- that is, the minimum power at which you will move at all due to friction in the system) should work okay.

We have sufficient damping in our drive system that overshoot is nearly negligible, so I've advised our team just to use proportional power rather than dealing with the PID class. Arm angles, on the other hand, are a different story...