Quote:
Originally Posted by Alan Anderson
We did it. But it's not going to be on our competition robot.
We put a strip chart on the Dashboard to display the RPM as measured by the encoder. Our programming students decided they weren't satisfied by the amount of overshoot it showed, and implemented a simple PID controller. A few minutes of tuning later (plus some tweaking of the algorithm to limit integral windup), it works great.
The continual loud snaps and clicks from the gearbox when using bang-bang were rather disturbing to most people hearing them. The simple PID sounds smooth as silk, appears to bring the motor up to speed just as fast, and recovers quickly from a brief additional load without problem.
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Very impressive it the performance is truly comparable.
Are you doing PID on velocity itself?
Is it output = PID, or output += PID?
Are you using all three terms?
Are you limiting the motor to never allow a negative power applied?