I thought that PID controllers as a family can only give at most 90 degrees phase lag. I did not consider that PI-D or I-PD would give more.
In some cases of robust control where some parameters of the plant may vary, the boundary of the closed-loop gain takes the shape of a cylinder on the...
Sorry, I was thinking of meeting gain margin and phase margin requirements but I didn't mention the context in my examples. In those two examples, one would use a lead-lag or a series of them to shape the response, because PID controllers don't give zeros to use. If I derive the frequency...
I was asking it as a general question. I don't have a specific application in mind. By "PID controllers" I meant the family of controllers with P and/or I and/or D controls (i.e. it includes P, PI, I-PD, etc).
I can only think of a couple cases:
1) when I need the controller to increase or...
Hello. How do you know when you cannot apply PID-controllers to a system? Have you had an experience where you first thought that a PID-controller might work but eventually find it impossible? How would you decide?
