Q1. Consider the unity feedback control system with a PI controller shown below:
a) Determine the closed-loop transfer function and the characteristic equation of this system.
b) Determine the range of k for which the closed-loop control system is stable.
c) Let k = l. Compute the steady-state error ess for a unit-ramp input, U(s).
d) How would you modify the PI controller to get ess = 0? Justify your answer.