Anti-windup For Singularly Perturbed Switched Systems And Its Application To Hydraulic Servo System

In practice,there exist many control systems with switching characteristics and multi-time scale characteristics,such as power electronics system,hydraulic servo system,and networks communications.These kinds of systems are usually described as singularly perturbed switched systems(SPSSs).Since actuator saturation is a typical nonlinearity,the traditional singular perturbation theory is limited to smooth systems,the anti-windup control problem for singularly perturbed switched systems is still open.Therefore,this thesis studies the design and analysis of the anti-windup controller of the singularly perturbed switched systems.The main works are summarized as follows:1.An anti-windup control method for nonlinear singularly perturbed switched systems with actuator saturation is proposed.First,an anti-saturation controller consisting of a dynamic state feedback(DSF)controller and an anti-saturation compensator is designed.Then,two methods are proposed to determine the anti-windup controller gain matrices by a common Lyapunov function.(1)Assuming that the singular perturbation parameter ? is available and designs ?-dependent anti-windup controller gains simultaneously.(2)Considering the case that ? is unknown but sufficiently small,designs the ?-independent DSF controller gain matrices first and then designs the ?-independent anti-windup compensator gain matrices.Both of the methods are reduced to solving convex optimization problems and can achieve larger stability bound and basin of attraction than the existing results.Finally,examples are used to illustrate the feasibility and advantages of the proposed methods.2.An anti-windup control method for singularly perturbed switched systems subject to external disturbance is proposed.Firstly,the disturbance observer that relies on the singular perturbation parameter ? is designed to estimate the external disturbance.Secondly,the anti-windup controller that takes the estimated value of the disturbance into account is designed,and controller gain is obtained by using the H? theory and the Lyapunov stability theory.Finally,simulation results show that the designed controller can make the system stable with disturbance tolerance capability.3.Based on the above proposed methods,the anti-windup control method of the hydraulic servo system is proposed.Firstly,a mathematical model of hydraulic servo system based on singular perturbation theory is established.Secondly,the disturbance observer and the anti-windup controller are designed.Finally,the stability and dynamic performance of the system are analyzed through simulation.