% Compute closed-loop transfer from u to y
D1 = getIOTransfer(T1,'u','y');
D2 = getIOTransfer(T2,'u','y');
D3 = getIOTransfer(T3,'u','y');
step(D1,D2,D3,10)
title('Disturbance rejection')
legend('\alpha = 1','\alpha = 2','\alpha = 4')13 Control System Tuning Examples