Robust Reliable Control For Complex System

With the rapid growing application of science and technology, the industrial equipment becomes more complicated. And the security and reliability of the equipment, especially for the large-scale complicated equipment, is attracted more and more attention. If any components fail and can't be disposed in time when the equipment is running, it will not only result in great economic loss but also probably endanger people's safety, which will have a bad influence in society. With the development of automatic manufacturing, it is impossible to satisfy the requirements of modern manufacturing to possess security, reliability and steadiness only by traditionally passive maintenance. The security and reliability have become two important goals of systems designing and developing. Fault-tolerant control (FTC), developed in 1980's, is a kind of control technology which aims at improving systems reliability. It is to ensure the system running continuously with security, effectivity and reliability or performing the expected function at specified time at the cost of losing some performance by using some effective methods, when one or more than one component of the system fails or is ready to fail. Robust fault-tolerant control is the focus in the research of FTC recently. It is to design a robust controller in advance to ensure the system possessing integrity against sensor or actuator failures. In this dissertation, a detailed analysis of the current situation of study on fault-tolerant control and a discussion about the problems of fault-tolerant for complex systems are stressed. Based on a general representation of sensor and actuator failures, we study some kinds of robust fault-tolerant control problems for uncertain systems and uncertain time delay systems and uncertain nonlinear systems which are described as state-space models. Concerning the linear systems with norm-bounded uncertainties, the analysis of robust stability, the design methods of robust stabilization controller and the design of controller that guarantee certain robust performance by state feedback are investigated, and later we obtain some corresponding results. The main results of this paper are outlined as follows, 1. The background related to the subject is summarized and some preparation information on LMI and MATLABLMI toolbox and lemmas used in the dissertation and standard H∞ control problem and bounded real lemma. 2. The robust stabilization problem for time delay uncertainty continuous systems is considered. By using linear matrix inequality, a sufficient and necessary condition for the system robust stabilization against sensor and actuator failure is presented, and the results are given in terms of linear matrix inequalities. A simulation example is given finally. 3. The problem of state feedback robust stability for a class of uncertainty time delay continuous systems with state delay is studied. Based on linear matrix inequality and Lyapunov stability theory, a sufficient condition for the system to be asymptotically stable against sensor and actuator failures is presented and the corresponding design method of robust fault-tolerant control laws by state feedback is provided. An illustrative example is given to illustrate the obtained results. 4. The robust H∞ control problems of nonlinear systems with state perturbations are studied. The corresponding sufficient conditions for the solvability of H∞ control problems against sensor and actuator failures via the state feedback control, while the design methods of the controller are proposed. An illustrative example is given to illustrate the obtained results.