Research On Adaptive Fault-tolerant Control For Asynchronous Systems

In this paper,a series of adaptive fault-tolerant controller algorithms are proposed for Markovian jump systems with asynchronous phenomena between system modes and controller modes.The purpose is to design suitable fault-tolerant controller to ensure the stability of the system in the case of both actuator failure and external disturbance.The main contents of this paper are as follows:(1)For the system with the actuator failures and disturbances which satisfies the constraint.Firstly,the asynchronous phenomenon is described by a Hidden Markovian Mode,the corresponding values of the partial failures and the upper and lower bounds of unknown disturbances are estimated via the adaptive laws.Furthermore,the adaptive fault-tolerant controller is provided based on the estimated results,and the effects of failures and disturbances can be compensated automatically.By utilizing the Lyapunov stability theory,the stability of the closed-loop system can be guaranteed in the presence of failures and unknown disturbances.Finally,the effectiveness of the method is verified by two numerical examples.(2)Considering the asynchronous Markovian jump systems with actuator partial failure and bias failure.By utilizing the augmented technology,a new disturbance is obtained.A disturbance observer is designed to estimate the augmented disturbance and the disturbance compensation gain is designed by it.The value of the partial failures is estimated via the adaptive law.The adaptive fault-tolerant controller is provided based on the estimated results.Due to the observer errors are inevitable,it is necessary to design a fault-tolerant controller to make the closed-loop system meet H? performance.By utilizing the Lyapunov stability theory,the stability of the closed-loop system can be guaranteed in the presence of failures and unknown disturbances.Finally,the effectiveness of the method is verified by a numerical example.(3)When the actuator failure includes partial failure,bias and stuck failure,the influence of unmatched external disturbance on the asynchronous system is considered.Based on Hidden Markov Model,the corresponding disturbance observer is designed to weaken the influence of external disturbance on the system.The adaptive law is used to estimate the stuck failure and partial failure,and an indirect adaptive fault-tolerant controller with multiple failure types is proposed.By selecting the appropriate Lyapunov function and using lemma of Schur-complement to solve the partial gain of the controller and the sufficient condition of the existence of the controller can be obtained.Finally,the effectiveness of the method is verified by a numerical example.