Fault Detection Of Networked Control Systems With Time Delay Packet Loss And Interference

With the rapid development of modern network technology,the network control system with its unique advantages is widely used in automobile manufacturing,power system and other industries.It has brought great convenience to life and production,but due to the involvement of the network,it brings some new problems.These problems have may cause some problems,like system instability,and they even may endanger the production and life safety.So the network control system is of great significance to study the fault detection.This paper mainly studies the fault detection problem of linear and nonlinear NCS under several assumptions.Firstly,this paper considers,in the case of packet loss,the problem of fault detection for linear time-varying time-delay.We designed the fault observer based on asynchronous dynamical system theory and linear matrix inequality method.And then,the effectiveness of the method is verified by simulation.To the problem of modeling the system,we used asynchronous dynamic system theory to model an asynchronous dynamical system with two event constraints(ADS);To the problem of fault detection,we modeled the state observer of the system,fault detection is carried out by residual size;For the problem of stability,according to Schur lemma and Lyapunov stability theory,we analysed the stability of the system.Secondly,the fault detection problem with linear delay,packet loss and norm bounded disturbance is studied.Based on the asynchronous packet loss,we constructed the robust fault observer system,we can get the information of the system's fault by comparing the output of the fault detection and the output of the original system;according to the minimum value method for solving linear matrix inequalities,we can get the selection method of system fault detection threshold;finally according to Schur lemma and Lyapunov stability theory,sufficient conditions are given for system stability.Finally,the proposed method is extended to nonlinear systems,and the problem of fault detection is studied.By using the T-S fuzzy model,the nonlinear part is linearized at the operating point,the global model of the system is established,and then according to the analysis method of linear model,we can get the system's structure and the we discussed system stability.