DP8.5 Consider the control system depicted in Figure DP8.5

(a) where the plant is a “black box” for which little is known in the way of mathematical mod

els. The only information available on the plant is the frequency response shown in Figure DP8.5(b).

Design a controller G s c ( ) to meet the following specifications: (i) the crossover frequency is be

tween 10 rad/s and 50 rad/s; (ii) the magnitude of the loop transfer function is greater than 20 dB for

ω < 0.1 rad/s.