Consider the following system shown in Fig.2 (attached file) in which a PID controller is used to control the system.
The PID controller has the transfer function Gc(s) = Kp(1 + 1/Tis + Tds)
Design a PID controller for this system using Ziegler-Nichols tuning method for determination of Kp, Ti and Td. Then obtain a unit-step response curve and check to see if the designed system exhibits approximately 25% maximum overshoot. If the maximum overshoot is excessive (40% or more), make a fine tuning (most suitable tuning) and reduce the amount of the maximum overshoot to approximately 25% or less.
PID Controller and Ziegler-Nichols Tuning Method are investigated. The solution is detailed and well presented. The response was given a rating of "5/5" by the student who originally posted the question.