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Unread 11-02-2007, 15:58
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Re: How to tune a PID loop?

Quote:
Originally Posted by steve d View Post
What would be some typical gains? I'm playing with a bench setup here, motors aren't really loaded or is follow-up pot connected, tough doing it open-loop. I have a gain of 1 for P term, 10/100 for I and D. Seems pretty good, If I up the I gain to 25/100, the error builds up fast and I suspect the real thing will overshoot.
We're using it to "slave" the arm position to the joystick position.
Gain depends strongly on what your inputs are, how they are loaded and what your outputs are.

The simple approach is

1. Start with a small P, no I or D.
2. Adjust until the response is about what you want.
3. Add just enough I to eliminate undershoot.
4. Add just enough D to eliminate overshoot.

(This is a gross oversimplification. Read the whitepaper on PID without a PhD here on CD).