clear all; close all; s = tf('s'); P = 1/(s^3+1.5*s^2+1.5*s+1); % example of open-loop system K = ss(1); % controller figure(1); bode(K, 'b'); hold on; figure(2); nyquist(P*K, 'b'); % check for closed-loop stability hold on; S = 1/(1+P*K); % sensitivity function figure(3); bodemag(S, 'b'); % gain characteristic of sensitivity function hold on; figure(4); T = 1 - S; % complementary sensitivity function step(T, 'b', 10); % step response hold on;