Anti-windup control using saturated state observer

We consider the windup phenomena which is usually observed in servo systems. Due to the integral term of servo controllers, windup phenomena arise when the control input to the plant is saturated. It is not only with PI or PID servo controllers, but also with high order servo controllers which contain nearly zero poles, for example, designed by the H_∞ optimum control theory. To avoid this problem, anti-windup (AW) control algorithms have been proposed. In this paper, we investigate some effective methods for the high order servo controllers, and propose a new AW strategy based on a saturated state observer