Robust Fault Detection Filter Design for Nonlinear Networked Control Systems with Time-Varying Delays and Packet Dropout

This paper deals with the problem of detecting faults in nonlinear networked control systems. The considered system is the state space models of time-varying systems in which the upper and lower bounds of delay are known. Sector-bounded condition is exploited to overcome the nonlinear term. It is assumed that data packet dropouts occur during data transmission, which here is modeled as Bernoulli-distributed white sequences. For fault detection, an H-/H∞\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$H_{-} /H_{\infty }$$\end{document} performance index is utilized to design an observer such that the residual signal is much sensitive to faults and less sensitive to disturbance. The Lyapunov–Krasovskii approach is exploited to ensure the stability of the designed observer. The obtained results for observer design are modeled as linear matrix inequalities. Finally, a numerical example and a practical example of engineering systems are adopted to illustrate the effectiveness of the proposed approach.