Stabilty Analysis And Control Of Interval Type-2 Discrete-time T-S Fuzzy System

Stability analysis and controller design of the discrete-time fuzzy system are important subjects in the fuzzy system theory. The change of external environment and the abrasion of the system components cause the uncertainty of the actual non-linear control system. The traditional processing method based on T-S fuzzy model, using the certain membership function, cannot fully describe the uncertainty of the system. Therefore, analysis and integration method is conservative. The theories of interval type-2 fuzzy sets extend the theories of type-1 fuzzy sets, inheriting its advantage, enhancing the ability to describe the uncertainty of system. This thesis, based on the analysis and integration for the uncertain discrete fuzzy system made by interval type-2 fuzzy model, improves the previous studies, and reduces the conservative property of design. The specific studies are as follow:Firstly, based on the interval type-2 fuzzy model, interval type-2 discrete-time fuzzy system is established. For the problem of actuator failures and time-varying delays in the practical system, a fault-tolerant controller not matching the membership function is designed, which can make the closed-loop system stable and be of H∞performance. The simulation results are given to demonstrate the effectiveness of the fault-tolerant controller. Secondly, when the state is unmeasured, observer-based controller is designed, and sufficient conditions for the existence of such a controller are obtained. Moreover, the simulation results are given to demonstrate the effectiveness of the method proposed. Finally, for the problem of guaranteed cost output tracking control, a guaranteed cost output tracking controller based on the IT2 T-S fuzzy system is designed, which makes a great trace between the given reference model and the system. The simulation results are given to demonstrate the effectiveness of the output tracking controller. This thesis provides the basis and reference of the theory and application for the IT2 T-S fuzzy discrete-time systems.