PID control

Is it true that tuning of PID parameters are purely heuristic? Are there no algorithms or formula to get the parameters?

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On Mon, 13 Aug 2007 14:34:09 +0000, hlseck wrote:

Tuning a PID loop _can_ be done in a more or less heuristic manner -- see the second half of the article: http://www.wescottdesign.com/articles/Sampling/pidwophd.html . This sort of heuristic tuning works when your system can work adequately with a wide range of tuning constants. Unfortunately, without experience the only way you can tell if this is so is to give it a whirl.
But there are any number of formal methods for tuning PID controllers ranging from the traditional frequency response method (see my book, http://www.wescottdesign.com/actfes/actfes.html , for details) to other system ID+design methods, to completely algorithmic automatic on-line adaptive tuning methods.
Most of the methods that put you in the driver's seat not only let you find the right tuning values, they also give you some sort of metric to predict performance and system robustness. If you know enough about what you are controlling it allows you to do your preliminary tuning before the system is even built, and hence decide if the performance will be adequate or if you need to change the proposed plant design.
So you can pretty much pick your poison.
--
Tim Wescott
Control systems and communications consulting
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