In PID tuning using control system tuner why am i getting waveform like this? Why there is no S and T and why in speed response plot its showing zero in actual?

I am trying to tune my PI controller using control system tuner as exactly as in http://in.mathworks.com/videos/automatic-tuning-of-multi-loop-dc-motor-controller-91844.html. But Im unable to get plots as in figure.

Answer 1

[Arkadiy Turevskiy]

Control System Tuner works by linearizing a Simulink model and then trying to design a controller for the linearized model. You have Universal Bridge block in your model, which models the switching. Switching linearizes to zero, therefore you see the results you see. Try changing the model to eliminate switching behavior when you design your controller. Then, once you design the controller, you can verify it in the model that has switching.