PID Ziegler-Nichols - Second Method

Jun 08, 2011 1 Replies

People,



I am doing my undergraduate thesis about a electronic throttle control, and i am trying to tunning this using a PID controller and the second method.



The books always says we must keep increasing the gain until the system output oscilllate. But if i keep increasing the gain without change my reference in my system it just doesn't oscillate.



if i change the reference like square wave and than keep incresing the gain, this will start to oscillate and than i can measure the periode and the gain critical.



Do you know if that's all right? because the books does't say o have to change the reference or you can change the reference.


Thank you, Maur=EDcio Mendes


This is a simulation rather than a prototype, right?

So if your simulation has exactly two poles, the overshoot will get arbitrarily bad as you turn up the gain, but it'll never actually oscillate.

Hint: Try measuring a real system and making a more realistic model.

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 email: hobbs (atsign) electrooptical (period) net http://electrooptical.net

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