I have a vehicle (I bought it and it proprietary and I have no information about any internals) which I want to integrate into my simulation environment. So far I have a physical model of it which I gained by driving around recording data and building a physical model from it. Now I'm at the point where I want to model the internal controller. I though that it might use a PID but I think now that something else is used instead. First I ran (around 30k) simulation with the physical model as basis to come up with the PID constants. In the simulations I let the vehicle move around the way as I did with the real vehicle and compared the response of my controller with the measured response of the real controller. In the image below you see the best PID which my brute force parameter search came up with.
As you can see my PID (red line) does not respond as fast as the real controller (green line) So my question is now:
What kind of controller could have been used here ? And how can I model it ?
It is definitive not a PID. Ten year ago I had lectures on control and system theory but since then I did not need to build a controller so I have not much experience. I looked into the literature and found the Lead–lag compensator which look promising but I have no idea where to start or how to implement it. To get the constants here I again can run simulations in a try an error manor. Maybe another different approach has been used but I have no idea what.