Optimal Tuning of PI/PID/PID(n-1) Controllers in Active Disturbance Rejection Control

Abstract

A new method based on the LQR approach is proposed for the optimal tuning of the Active Disturbance Rejection Control (ADRC). The input-output behavior of a complex system is approximated by a low order local model that allows designing PI and PID controllers into the ADRC framework. By imposing the condition of guaranteed dominant pole placement, it can be proposed a criterion for selecting the Q and R matrices in order to have a desired percentage overshoot and settling time of the closed loop response. It is also considered the extension of the method when the local model has a general order n, in this case, the controller will be of the PID ^(n-1) type. Some numerical examples are considered to show the effectiveness of the approach.