Predictor based 2DOF control design for inverse response processes with time delay

Abstract

Industrial processes with inverse response and time delay are difficult to control due to the presence of right half plant (RHP) zeros in the transfer functions. A predictor based two-degree-of-freedom (2DOF) control design is proposed in this paper for such processes of stable or integrating type. The proposed control system design is based on using a dead-time compensator (DTC) to predict the non-minimum phase (NMP) dynamics, such that a delay-free closed-loop control design could be established for performance optimization. By proposing the desired transfer functions for the set-point tracking and load disturbance rejection, respectively, the corresponding controllers are analytically derived in discrete-time domain for implementation in sampled systems. Illustrative examples from the literature are shown to demonstrate the superiority of the proposed control design.