Robust Fault Identification Research Of Nolinear Time-delay Systems Via T-S Fuzzy Model

Fault diagnosis and fault-tolerant control technologies have been attracting much attention as one of the most commonly used methods to ensure the system stability and security.However,with the development of automation technology,more and more factors need to be considered in practical engineering,such as time delay,nonlinearity and diaturbance,etc.,which makes the traditional control methods more and more unsuitable for the complex industrial systems today.Therefore,this article carries out the research of fault diagnosis technology for a class of nonlinear time-delay systems with complex mathematical models.Firstly,This article focused on the problem of fault estimation for a class of nonlinear systems with time-varying delay,a fault estimation observer is constructed to achieve the faults estimation respectively when the actuator and sensor faults occurred at the same time,and then,the conditions for the design and implementation of the observers are given in the form of linear matrix inequalities.Finally,the effectiveness of the proposed method is verified by two simulation examples,which means that,the observer thus designed can not only realize the functional of fault estimation,but also satisfy the performance index simultaneously.What's more,on the basis of previous work,the time-varying delay is extended to the interval time delay,which makes the system closer to the actual system.Although the idea is the same as before in the process of designing the observer,by constructing an appropriate type of Lyapunov function including the information of the lower and upper bound information of time delay,the sufficient delay-dependent conditions are established to reduce the conservatism,and the effect of fault estimation will be better.Finally,the conditions for the design and implementation of the observers are also given in the form of linear matrix inequalities,and the simulation results show that the proposed method is valid.Finally,after obtaining the fault estimation information,this article studies the fault-tolerant control system from two aspects.One is a fault-tolerant controller based on the state feedback principle.The controller uses the state variables of the original system as input,and then compensates the faults through two outputs respectively.The simulation results show that the controller works well.However,this method requires that the state of the system must be observable or measurable.The other is a fault-tolerant controller based on the output feedback principle.The controller takes the output variables of the original system as input and then compensates the faults separately,for most systems,the output variables are readily available,which widens the scope of this method.The final simulation results prove that the proposed method is effective.