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by rcxdude
2228 days ago
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It does depend on the system you're controlling, often there's a natural integral in there and so you effectively 'shift' everything down one (P acts more like I, D acts like P, and I is a double-integral). Like how PD is fine for the quadcopter control until wind is added to the simulation. |
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The main price of an integrator is 90 degrees of phase lag; this will harm the stability of many systems but as long as it's kept at a low bandwidth it's usually fine.
The main price of derivative gain is high frequency noise amplification, and so a well designed PID will have a limited bandwidth for the D term as well. For many systems, especially those that are already damped or don't need the extra phase margin, it's not needed or not worth the noise cost.