Study On Control For T-S Fuzzy Systems With Time-domain Constraints

Time-domain hard constraints, including actuator saturations and output con-straints are probably the most widely encountered and most dangerous nonlinearityin practice control systems. It is well recognized that hard constraints degradesthe performance of the control system and may even lead to instability. But, highperformance requirements for control systems, such as fast transient response, highlevel of disturbance attenuation, imply large control actions (and/or large systemresponses). All of these result in the con?ict between high performance and satis-faction of time-domain hard constraints.'Higher'gain will be derived if one ignoresthese constraints and only performance is treated while designing state-feedbackcontroller. Control action will exceed the bounds greatly even the system errorsare very small, especially the system is encountered by abrupt reference change orimposed external disturbances. In such case, the control action needs to be clippedto the bounded level, but performance of closed-loop system would't be guaranteed,even of stability. In sum, time-domain hard constraints must be handled in somecontrol system design and controller design for constrained system is actually tomanage the trade-o? between high performance and satisfaction of constraints. Anobjective of a control system is to improve the performance using limited controlaction.The objective of this paper is to present systematic approaches to the de-sign of the state-feedback controller for T-S fuzzy systems with time-domain hardconstraints, which can guarantee the performance of closed-loop system and time-domain hard constraints are satisfied meanwhile. The ellipsoidal invariant sets areintroduced when handling constraints. The main idea of these approaches is toseek an ellipsoidal invariant set that contains all possible state trajectories, andthen su?cient conditions dependent on this set that guarantees satisfaction of con-...