PID CONTROLLER DESIGN AND EVALUATION Expand Simulink model to include a PID controller for rotor angle (find the new Transfer function), using the signal generator to create a square-wave reference signal, with amplitude = 1 radian and frequency 0.4 Hz. Selecting the PID gains kp = 1, kd = 0, ki = 0, K= 40, T = 0.4 and you should obtain something similar to the result shown in Figure 6. To give consistent results it is recommended to set the Simulink solver to Runge-Kutta (ode4), fixed-step = 0.001 (use 'Model Configuration Parameters' option in the 'Simulation' menu). Describe the method you use to tune the three PID gains, and how each affects control performance. After you obtain your best result, compare with the initial result similar to Figure 6 and point out which performance metrics have improved and by how much. The actual motor has a limited input voltage of 15V. Use the PID Advanced tab to mimic this (set the upper and lower saturation limits to 15 and -15). How does this affect your results? Test your controller with another type of reference signal, e.g. a sine or sawtooth. What limitations are there, if any, when you operate the reference at (i) high frequency (5 Hz say) (ii) low frequency (0.2 Hz say)? Include plots and brief descriptions to explain your results. Scope File Tools Viev Simulation + Help 2 1.5 1 0.5 -0.5 -1 -1.5 -2 Ready AP x 2 3 5 6 7 8 10 T=10.000