How do I determine a good value for ki term in controller?

Rookie controls question here:

Here is an image of my controller:

The controller works fine when I set the ki = 0, but holds a 5m error. My controller diverges after 150 seconds when I set the ki value to -.01. what is a good way to determine the appropriate ki value?

Answer 1

[Ameer Hamza]

I suggest using the PID controller block: https://www.mathworks.com/help/releases/R2020a/simulink/slref/pidcontroller.html, which has a built-in tune option.

[Alok Virkar]

I tried this, but the tune function gives a warning that says it cannot find a stabalizing controller

[Ameer Hamza]

It seems that there is some instability in your system. Therefore, the tuning function of the PID block failed. In that case, I guess you need to follow the manual tuning methods mentioned here: https://en.wikipedia.org/wiki/PID_controller#Manual_tuning