Security switching control of cyber-physical system with incremental quadratic constraints under denial-of-service attack

This paper presents an observer-based security control scheme for a nonlinear cyber-physical system (CPS). Specially, the nonlinearity satisfies the incremental quadratic constraints ([Formula: see text]) which can represent many types of common nonlinearities. The problems are discussed under the assumption that both the feedback and forward channels may suffer from denial-of-service (DoS) attacks. The attack model is constructed in the form of time-delayed switching system with four subsystems corresponding to different attack situations. Then by using the attack model, an observer-based controller is constructed in the cyber layer to stabilize the CPS encountering DoS attacks. The closed-loop stability is analyzed based on H ∞ index of switching systems in view of average dwell time (ADT) concept. Besides, the gain matrices of the controller and the observer are obtained by solving a series of matrix inequalities using an algorithm designed in this paper. Finally, the performance of security control scheme is presented by a simulation example.