What PID tuning method would your recommend (not including Ziegler Nichols) to do the following problem? Also where can I find information on how to perform the tuning?

Using a PID tuning algorithm of your choice (search the literature), design a PID controller for a DC motor plant, such that the steady state error in following a step function is less than 1% and the settling time is less than 0.1 second. Assume that the DC motor has a transfer function: K/(s(s+a)) with K=1 and a=1.

-- Joel Mathias (pjm32@drexel.edu), May 24, 2004

Answers

What about overshoot?

I'd suggest getting your hands on a copy of 'Control Systems Engineering' 3rd ed. by N. Nise and having a look at Example 9.5 if you are looking to design a PID from a transfer function.

NB Zieglar-Nichols is used for systems when you don't have a transfer function of the plant.

-- Charles (crr102@york.ac.uk), May 25, 2004.

I think pole placement is the best if you have the transfer function.

The answer is:

Ki=(lambda^3)/(K*a) Ki=1 Kp=(3*lambda^2)/(K*a) Kp=3 Kd=(3*lambda-a)/(K*a) Kd=2

Assuming lambda is 1. Increase lambda to get the response you want. There is a practical to how much you can increase lambda. The delay between reading the encoder and changing the output and quantizing will limit how much lambda can be increased. The CLTF will have 3 real poles at -lambda. Simple.

-- Peter Nachtwey (peter@deltacompsys.com), August 01, 2004.