Model Based PI Tuning Rule with Ultimate Gain and Phase Margin Criteria

Abstract

The control of various processes using a proportional-integral (PI) controller is investigated in this work. A new tuning rule based on the ultimate gain and phase margin specification is proposed. The tuning rule is given by analytical approximations. To obtain the tuning rule, a control signature is formulated using the ultimate properties of the system. The PI controller parameters are related with process model parameter to yield a model based tuning rule. Simulation examples are provided to demonstrate the performance and robustness of the present tuning rule. The new tuning rule requires a relatively small computational effort and is particularly useful for online applications.