Parity Space-Based Fault Detection for Networked Control Systems Under DoS Attacks

This paper presents a parity space-based fault detection (FD) method for networked control systems (NCSs) subject to denial-of-service (DoS) attacks resulting in packet dropouts. To begin with, a parity relation that takes into account DoS attacks is constructed utilizing the available input and output data during a time-varying window. Based on the parity relation, a residual generator is proposed without introducing transmission errors caused by DoS attacks. Additionally, an H−/H2 optimization scheme is developed for the design of residual to achieve a trade-off between the sensitivity to faults and the robustness against the disturbance/noise. Then, an adaptive residual evaluation function with a unified threshold is also proposed for no DoS attack scenario and DoS attack scenarios. Furthermore, the relationship between the traditional residual generator with the proposed one is explored, and an online FD algorithm is presented. Finally, the effectiveness of the proposed approach is demonstrated on a linearized longitudinal model of an autonomous underwater vehicle (AUV), and a comparison with an existing parity space approach is also provided.