Anti-windup design for discrete-time systems with time delay via predictor-based extended state observer

A novel anti-windup design is proposed for discrete-time systems with time delay and actuator saturation. Based on a generalized predictor to estimate the undelayed system output, a modified model-based extended state observer (MESO) is designed to simultaneously estimate the system state and disturbance, which becomes an anti-windup compensator when actuator saturation appears. Accordingly, a feedback controller is analytically designed to stabilize the system and reject disturbance. By proposing the desired closed-loop transfer function for the set-point tracking, a pre-filter is designed to ensure no steady-state output tracking error. Using the generalized sector condition and generalized free-weighting-matrix (GFWM), a sufficient condition guaranteeing the stability of the closed-loop system is established in terms of linear matrix inequalities (LMIs). The effectiveness of the proposed control design is demonstrated by an illustrative example from the literature.