How to reduce linear actuator tracking error? PID Tuning

Hi there,

This is my first time using simulink so I've decided to work through the example "Linear electric actuator with control" (rct_linact).

I've set the target of reaching 1000RPM in 0.1s using the Control System Tuner.

However, I cannot reduce the Tracking error thus reach a suitable response time. I've been following the example given by Matlab: I'm struggling to tune a response time below the default 2000RPM.

How could I amend the control loop to acommodate for a smaller target speed?

Figure: tuned result after setting the target parameters.

Any help would be greatly appreciated, thank you for reading.

Answer 1

[Dinesh]

Hi Gabriel!

You can try the following approaches to solve the problem.

1. Adjust the sampling time: A smaller sampling time can help to reduce the tracking error of the system. You could try reducing the sampling time by selecting "Solver Configuration" in the model settings and adjusting the "Fixed-step size" parameter.
2. Increase the Proportional gain of the controller: This will increase the controller's ability to respond to changes in the system.
3. Increase the Derivative gain of the controller: This parameter affects the amount of damping in the system and can help to reduce overshoot.
4. Reduce the Integral gain of the controller: A high Integral gain can cause the system to become unstable and cause overshoot, especially if the target speed is small.

Please refer to the following MATLAB documentations for more details

1. https://www.mathworks.com/help/simulink/ug/how-to-specify-the-sample-time.html
2. https://www.mathworks.com/help/simulink/slref/pidcontroller.html

Hope this helps!