On the security and stability for wireless networked control systems with external attack and disturbances

Abstract

This article studies the security of wireless networked control systems (WNCS) with consideration of external attacking and system disturbances. The purpose of the attacker is to interfere with the information transmission, so as to break the stability of the system. It is a common mode of Denial of Service (DoS) attack. To preclude the cyber-attack from the attacker, the power control for the legitimate transmitter is considered. And the Stackelberg game framework is proposed to model the interaction between the attacker and the transmitter, where the legitimate transmitter acts as the leader and the attacker acts as the follower in the cyber-layer. The physical-layer combines linear quadratic regulator (LQR) control with sliding mode control to design the control strategy. Firstly, the LQR-based optimal controller is studied for WNCS under the DoS attack, and the conditions for satisfying exponential stability are given. Then, considering parameter uncertainty and external disturbance, the robust optimal controller based on the initial optimal controller is studied. It is worth noting that the designed controller has good robustness and can effectively reduce the quasi-sliding-mode bandwidth. The effectiveness of the proposed control strategy is proved by using the Lyapunov stability theory. Finally, a numerical simulation is performed to verify the effectiveness of the proposed method.