Hello

I have two design problems I would like to share and would appreciate feedback.

- Given a transfer function of Gp = -2/(1+3s). Design a PI controller to obtain a closed loop response time of 4.5s.

- For a process of Gp = 2(1-s)/(1+s)^2 and a PI controller given by

Gc = Kc(1+Tis)/Tis

Determine the values of Kc and Ti in order to have the fastest response time and a phase margin of 60 deg.

My progress so far on No1. is that I know that for the 5% settling time 3T = 4.5 therefor the time constant of the system is 1.5s. I am getting muddled up how I can relate this to the closed loop system.

For No. 2 I have tried several ways but don't seem to get anywhere.

Any help appreciated.

Ashley Watson