Tuned PID motor controller leads to a slow response

I am modelling an Electronic Throttle with the aim of choosing the right sized motor. I have tried to implement a PID control to my motor controller but it is leading to a slower response than expected. When I remove the PID controller and run the motor simply the response it much faster. I have used the tune function on matlab but it is still not as fast as it should be. I have attached the simulink model and some images describing my issue.

My model including the PID control, leads to the follwing response.

Ideally the settling time should be <0.25s for this kind of input

Now the same mechanical model with a simple step input is much much faster in responding

Its response

Zoomed in

You can see the response to 50deg in this case is ~0.1s.

Is there anything I can do? on the PID tuner workspace I get the settling time should be 0.011s. Maybe I should control the brake port on the H bridge controller with a second derative?

Thanks for your help

Answer 1

[Neelanshu]

Hi IRO,

The response of the model with PID controller is much faster than the one with only step input.

In the case of PID controller rise time, defined as the time the response takes to rise from 10% to 90% of the way from the initial value to the steady-state value, is less than 0.5 sec much lower than rise time, between 1.08 and 1.1 sec, in the case of only step input. Furthermore, the settling time for the case with PID controller, between 1.5 and 2 sec, is far better than the case with only step input block.

You may refer to the following documentation to learn more about rise time and settling time:

https://www.mathworks.com/help/control/ref/dynamicsystem.stepinfo.html

Hope this helps