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Unread 04-09-2006, 16:29
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Matt Krass Matt Krass is offline
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AKA: Dark Ages
FRC #0263 (Sachem Aftershock)
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Re: Alternative Method for calculating “I” term in PID

Quote:
Originally Posted by KenWittlief
<snip>
Turning the system on and twiddling the 'knobs' for P I and D will drive you crazy :^) All that math stuff: the bode plots, the pole/zero diagrams... it really is necessary unless you have a control system that can characterize the open loop response of the system by hitting it with step functions.
While the mathematical formulas do work, there's not nearly as much trouble as you allude to in hand tuning a system by "twiddling" the values. In fact every value I've used for 358s PID loops were derived by tweaking P until I had a minimal steady state error, then tuning I to minimize that until a minor oscillation was present, then tuning up D to absorb that. After the initial calibration it takes an occasional tweak to fix the odd glitch or two, but otherwise it's worked reliably for us.
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Matt Krass
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I'm a FIRST relic of sorts, I remember when we used PBASIC and we got CH Flightsticks in the KoP. In my day we didn't have motorized carts, we pushed our robots uphill, both ways! (Houston 2003!)