Module 08 Controller Designs: Compensators and PIDs

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Design via Root-Locus IntroLead CompensatorPID Controllers DesignModule 08Controller Designs: Compensators and PIDsAhmad F. TahaEE 3413: Analysis and Desgin of Control tahaMarch 31, 2016 Ahmad F. TahaModule 08 Controller Designs: Compensators and PIDs1 / 34Design via Root-Locus IntroLead CompensatorPID Controllers DesignIntroductionReadings: , Ogata; , , Dorf & BishopIn Module 7, we learned to sketch the RL for any TFWe saw how poles change as a function of the gainK K was a Controller a constant controllerMany times,Kas a Controller is not enoughExample: system cannot be stabilized with a choice ofK-gainOr, settling time is still high, overshoot still badToday, we ll learn how to design more complicated controllersObjective:findGc(s) such that CLTF has desired properties suchas settling time, maximum overshoot.

Lag compensators Glg c (s): reduce SSE, so sometimes we want smaller SSE rather than shorter rise and settling time as in a lead compensator Optimal solution: lead-lag (LL) compensator— Gll c (s) = Gld c (s)Glg c (s) LL compensators provides the benefits of both lead and lag compensators

  Compensator