What does linearization do in MATLAB's PID tuner?

Question

I noticed that the PID tuner from MATLAB has a linearizatin step before tuning. What does this linearization step do? And why we have to linearize a model in PID tuning?

Answer 1

I'll try to clarify:

1. PID Tuner algorithm works on linear time-invariant models.
2. PID Tuner app in MATLAB does not do linearization. You provide it with a transfer function of a plant model, and it calculates PID gains.
3. On the other hand, when you press "Tune" button inside of a PID Controller block in Simulink, PID Tuner first needs to obtain a transfer function to use for tuning PID Controller gains. This step of obtaining a transfer function from a generally non-linear Simulink model is linearization. If you want to learn more about linearization in Simulink, please visit this page on linearization.