Fault Detection for Networked Control Systems with Time delays Based on Unknown Input Observer

In this paper, a fault detection method for NCSs with time delays is proposed. Under some equivalent transformations, the time delays of NCSs can be regarded as an unknown input. Using the unknown input observer (UIO) design method, a sufficient condition for the error dynamic system stability is given in terms of linear matrix equations. Based on the designed unknown input observer, an output residual is constructed to detect the system fault. Then a numeral example is illustrated to validate the effectiveness of the proposed method. Finally, some conclusions are given.