Improving Transient Performance in Tracking Control for a Class of Nonlinear Discrete-time Systems with Input Saturation

Abstract

This paper addresses a target tracking control problem for a class of SISO discrete-time partially linear composite systems with actuator saturation. Quick response and small overshoot are two desired transient performances of target tracking control. While most of the design schemes compromise between these two performances, we try to achieve both simultaneously by using a composite nonlinear feedback (CNF) control technique. The CNF control, consisting of a linear feedback law and a nonlinear feedback law, aims to improve the transient performance of the closed-loop systems. The linear feedback part is designed to yield a closed-loop system with a small damping rate for quick response, while the nonlinear feedback part is used to increase the damping ratio of the closed-loop system as the system output approaches the target reference to reduce the overshoot. We also show that the closed-loop system with improved transient performance preserves the stability of the nonlinear part of the partially linear composite system.