Note how disturbance rejection improves as alpha increases, but at the expense of
increased overshoot in setpoint tracking. Plot the open-loop responses for the three
designs, and note how the slope before crossover (0dB) increases with alpha.
L1 = getLoopTransfer(T1,'u');
L2 = getLoopTransfer(T2,'u');
L3 = getLoopTransfer(T3,'u');
bodemag(L1,L2,L3,{1e-2,1e2}), grid
title('Open-loop response')
legend('\alpha = 1','\alpha = 2','\alpha = 4')
PID Tuning for Setpoint Tracking vs. Disturbance Rejection