Can someone help in tuning PI controllers and hence to find Kp and Ki value for both PI controllers for this dc series motor system?

Please help me in tuning the attached system of dc series motor for a step change in speed. I am unable to get alpha constant. Alpha is always fluctuating even when there is no step change in w. But when i am applying a step change w is fluctuating badly. Since there are two PI controllers i am unable to find out and hence tune to give desired response. I have tried automatic tuning method as in mathworks videos but didnt help since i am a newbie

Answer 1

[Sabin]

We can use the existing tuning methods based on either experiment (e.g., Ziegler-Nichols based on step-response or frequency response) or analytical calculation (e.g., pole placement) as for any control system. Simulink Control Design offers some great tools for PID controllers tuning.

When dealing with cascade control systems we need to first tune the inner loop (fast dynamics) and then the outer loop (slow dynamics).