Anti-windup ADRC design for temperature control systems with output delay against asymmetric input constraint.

To tackle the asymmetric input constraint typically involved with industrial temperature control systems, e.g., there is a tuning range from 0 to 100% in the heating power, an anti-windup active disturbance rejection control (ADRC) is proposed for the practical application, in particular for dealing with output delay. Based on an artificial symmetric transformation for the asymmetric input constraint along with a delay-free output prediction, an anti-windup extended state observer (AESO) is firstly constructed to simultaneously estimate the delay-free system state and external disturbance for control design. When the input saturation constraint occurs, the proposed AESO could also offer anti-windup compensation. Then, a feedback controller is analytically derived by assigning repetitive-type poles for the characteristic equation of the closed-loop structure, followed by a set-point prefilter design to ensure no overshoot and output tracking deviation. Tractable linear matrix inequality based conditions are rigorously established to guarantee the asymptotic stability of the resulting closed-loop system under a specified initial condition. A benchmark example from a recent reference is used to verify the superiority of the proposed control method over some existing anti-windup control designs. Moreover, a real application to the temperature control of a jacketed crystallizer is shown in comparison with a recently developed control method with no anti-windup compensation.