Reliable Fault Detection for Nonlinear Networked Systems with Imperfect Measurements: A Multi-Packet Transmission Mechanism

In this paper, the reliable fault detection problem is investigated for a class of nonlinear networked systems with imperfect measurements. A novel measurement model is proposed to take the network-induced delays, random packet dropouts and sensor failures into consideration simultaneously. Different from commonly used single-packet transmission pattern, a multi-packet transmission mechanism is adopted in the sensor-to-filter channel, which allows the measured outputs being encapsulated into multiple packets and transmitted to the remote fault detection filter via different communication channels. In these channels, the network status may be quite different from each other. We aim to design a reliable fault detection filter such that, for all admissible unknown inputs and imperfect measurements, the error between the residual and the fault is kept as small as possible. By constructing an appropriate Lyapunov-Krasovskii functional, a sufficient condition for the existence of the desired reliable fault detection filter is established in terms of linear matrix inequalities, and the corresponding optimal filter parameters can be obtained by solving a convex optimization problem. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed method.