| As an effective method to study nonlinear systems,T-S fuzzy model can approximate an unknown complex nonlinear dynamic system with arbitrary accuracy by introducing a class of “IF-THEN” rules and using fuzzy membership functions to connect the global model of the system with the local linear subsystems model.At present,fuzzy control theory is generally used in the field of control science and engineering.The analysis and synthesis of T-S fuzzy systems will be a major development trend of control theory in the future.Due to the variability of the surrounding environment and load changes,the disturbance in the above-mentioned complex nonlinear system is widespread.Therefore,how to attenuate or reject the disturbance and improve the control performance of the system becomes particularly important.This thesis studies the composite anti-disturbance control of discrete T-S fuzzy systems subject to external disturbance,random jump mode and parameter uncertainty.In addition,it is difficult to model nonlinear systems.The model predictive control(MPC)strategy does not require the precise model of the system,and is favored by many scholars and engineers due to its receding optimization characteristics.The main innovations of this thesis are as follows:(1)The problem of composite anti-disturbance control of type-1 T-S fuzzy systems with external source disturbance,in discrete-time domain,is studied.The external disturbance is the matched disturbance generated by an exogenous system,whose model is known.First,a disturbance observer is designed to estimate the external disturbance.And then based on the cost function,combined with the nominal system state prediction model,the optimal control sequence can be obtained.This chapter innovatively proposes a composite anti-disturbance control strategy by combining disturbance-observer-based control(DOBC)and MPC.Then,based on the Lyapunov stability theory,linear matrix inequality(LMI)can be solved to obtain the disturbance observer gains and the type-1 TS fuzzy predictive controller gains.Finally,a set of numerical simulations prove the feasibility of the control mechanism proposed in this chapter.(2)The problem of composite anti-disturbance control of discrete type-1 T-S fuzzy semi-Markov jump systems with mode random jump and matched disturbance is studied.By designing a disturbance observer that relies on the mode to estimate the disturbance of the same channel as the control input,and then a composite controller combining DOBC and MPC is given.In addition,the sojourn time of the semi-Markov jump system in the discrete-time domain is infinite and uncountable;Therefore,the semi-Markov kernel(SMK)method is proposed,and the use of the upper bound of the sojourn time solves the difficulty of processing the sojourn time time-variant term of the semi-Markov jump system.Finally,the LMI method is used to find a set of feasible solutions to stabilize the closed-loop system with disturbance rejection performance.(3)The problem of composite anti-disturbance control based on the disturbance observer of interval type-2(IT2)T-S fuzzy semi-Markov jump system with parameter uncertainty,random jump mode and matched disturbance,in discrete-time domain,is studied.By aiming at the common parameter uncertainty problem in the system,the IT2 fuzzy set is used to make the parameter uncertainty captured by the known upper and lower membership function.On the other hand,the introduction of slack matrices reduces the conservativeness of the stability condition of the system.Then,combined with DOBC and MPC,the proposed new Lyapunov function,which is related to the system modes and fuzzy rules,is used to find the sufficient conditions for the system to be stable and the disturbance to be compensated.Finally,a set of simulation examples are given for verification. |
