Robust Stability And Control For Uncertain Systems

In various real engineering systems, time delay and uncertainty are often encountered, and their existence may result in unsatisfactory control systems performance, or even instability. Thus, to investigate the stability and control for time delay and uncertain systems is of importance in control theory and its application.This dissertation focuses on the following problems of time delay and uncertain systems: a) the problem of robust stability of uncertain time delay systems; b) the problem of robust H_∞ control of time delay systems; c) the problem of reliable H_∞ control of time delay systems; d) the problem of robust H_∞ control of a class of systems with sector nonlinear uncertainty inactuators. The main contributions are as follows:1) For a class of linear time delay systems with structured and unstructured parametric uncertainties, the problem of robust delay-independent stability is investigated. Some sufficient conditions for the robust delay-independent stability of the given systems are derived. These conditions are easily verifiable. Also, numerical examples show they are less conservative than those reported in the literature.2) For a class of linear multi-time delay systems with structured and unstructured parametric uncertainties, the problem of disk stability is studied. Some sufficient conditions for the disk stability of the given systems are presented. For the first time, the disk stability for uncertain multi-time delay systems is addressed in this dissertation.3) For a class of uncertain linear time delay systems, the problem of robust delay-dependent stability is concerned. Some sufficient conditions for the robust delay-dependent stability of the given systems are established. At the same time, estimates on the rate of decay of the original systems are also...