Decentralized PID controller design for TITO processes with experimental validation

Abstract

In this paper, a design method of decentralized proportional–integral–derivative (PID) controller for two-input two-output processes based on pre-defined reference transfer function is proposed. An ideal decoupler is used to reduce the interaction among system variables. Free structure higher order diagonal controllers are computed for each decoupled subsystem by specifying closed-loop response in terms of dominant reference second order transfer function. Further, to obtain controllers in PID structure, the higher order diagonal controllers are truncated into first three terms of Maclaurin series. The stability of resulting PID controller is investigated. Two benchmark examples are illustrated to show the effectiveness of the proposed controller. An experimentation is performed on interacting coupled tank process to demonstrate the applicability in real life applications.