Fault Detection of Networked Control Systems with Output Delays

Considering a class of networked control systems with long time delays,the fault detection is carried out supposing that the output delays are present between the sensor and the controller.The fault observer with delay compensation is constructed,and the state estimate error equation is given.Based on the theory of discrete switching systems,a linear matrix inequality is given to express the stability condition of this observer.When the system is normal,if the given inequality condition is satisfied,the observer system is asymptotically stable.When a fault is present,the observer residual can change rapidly and detect the occurrence of the fault.An illustrative example shows the effectiveness of the proposed method.