Saturation Control System Stability And Interference Suppression Study

Saturating nonlinear actuators is one of the common nonlinearities, and exists in many practical situations. If the control system is designed to be stable without considering the saturation, the stability of the closed-loop controlled system can't be guaranteed. In addition, as we know, it is almost impossible to obtain accurate mathematics model for object systems due to the complex dynamical behaviors in the practical control process under which the controller is designed is usually different to the real plant owing to some kinds of model approximation or reduction methods, and the difference can be regarded as a certain uncertainty. Since robust control theory is a powerful methodology of control law design for uncertain systems. On the other hand, it is well know that time delays can be encountered in various process due to the effect of transportation, measurement, reaction process, etc. A large number of practical systems can be modeled as time-delay systems. It is recognized that time delay often is the main source of instability and poor performance. Stability and performance are always the key issue in the control theory and control engineering, so the study of delay systems is noticed in the control theory literature. However there are few researches on saturating actuator systems in the exiting results on robust control theory. To the above systems there are several key issues to study deeply.With the survey of birth and development and the research on constrained systems, to systems with actuator/sensor saturation, uncertain saturating nonlinear continuous /discrete time systems, uncertain saturating continuous /discrete time systems with time delay, some issues are studied in detail in this thesis. Based on Lyapunov stability theory, Controller design strategies based on LMI and iterative ARE are developed.With the deeper analysis of state feedback single input linear system subject to actuator saturation, the paper presents a sufficient condition which guarantees the systems are GAS or RAS, calculates an invariant attractive ellipsoid for the...