Great papers you must read on this topic
SkogestadЃ, Sigurd. “Probably the best simple PID tuning rules in the world.” (2001).
Skogestad, Sigurd. “Simple analytic rules for model reduction and PID controller tuning.” Journal of process control 13, no. 4 (2003): 291-309.
A good baseline tuning is to probe its response to a disturbance. To tune a PID use the following steps:
- Set all gains to zero.
- Increase the P gain until the response to a disturbance is steady oscillation.
- Increase the D gain until the oscillations go away (i.e. it’s critically damped).
- Repeat steps 2 and 3 until increasing the D gain does not stop the oscillations.
- Set P and D to the last stable values.
- Increase the I gain until it brings you to the setpoint with the number of oscillations desired (normally zero but a quicker response can be had if you don’t mind a couple oscillations of overshoot)