ANTI-WINDUP FOR A TWO-DEGREE-OF-FREEDOM MODEL MATCHING CONTROL SYSTEM

In this paper, we propose a new anti-windup method with an initialization procedure that avoids overshoot in spite of saturation of control input. This method is based on a two-degree-of-freedom model matching (MM) control system. Instead of the control input and reference output, which are not affected by input saturation, the saturated control input and an output are used respectively for updating the reference output and feedforward input. Thereby, when the input becomes unsaturated, MM works well because the memorized values of the reference output that are used for updating the reference output correspond with the past output values. Furthermore, a procedure to initialize the reference model making the overshoots small is presented, even if the given control input is saturated. This method is adequate for systems in which overshoots are prohibited, such as temperature controls and machine tools. The effectiveness of the proposed method was verified using numerical simulations and experiments.