Security Control Of Networked Switched System Under DoS Attack

In recent years,due to the increasing of the complexity of various industrial system models,and its demand of remote control and low control cost,the networked switched systems with continuous dynamic and discrete signal have received more and more attention.However,due to the openness of the industrial network,the problem analysis of the networked switched systems with hybrid characteristics when they are attacked by malicious network is quite difficult.At present,the security control of the networked switched systems has become a research hotspot.The existing researches on the network security control are aimed at the single systems.For the networked switched systems,both the compensation-based security control problems such as observer,controller design and stability analysis,and the game-based security control problem such as network game modeling and design of offense and defense strategy,have not been properly solved.Therefore,this paper studies the above problems,and the main contents are summarized as follows:For the situation that the Denial of Service(DoS)attack and random packet loss simultaneously occur in the communication network of switched systems,and according to the joint probability distribution of the communication failure caused by DoS attack and random packet loss,an observer is designed to update the estimated states based on the successfully received information and generate the control input.Then,a sufficient condition for almost surely asymptotic stability of networked switched systems with unstable subsystems is derived by the average dwell time method.In addition,since the variables of system matrix inequalities are coupled,a new method for solving the feasible solutions of observer and controller gains is proposed.To deal with the situation that the communication channels of multiple subsystem are attacked by DoS attack,a game-based security control method is proposed to resist the DoS attack,and the competition process between the attacker and the intrusion detection system(IDS)is modeled as a N-coalition non-cooperative game.The optimal attack and defense strategy is obtained by its Nash equilibrium solution.In order to ensure the rapid recovery ability of networked switching system,the optimal controller gains of each subsystem are given according to the dynamic programming principle,and the optimal switching signal is searched by using genetic algorithm without any switching signal parameters,which compose the resilient control strategy of networked switched system.Then,this method is applied to the networked continuous stirred tank reactor(NCSTR)system,and the effectiveness of the obtained strategies are verified.In order to reduce the defense cost,the game theoretic method for the networked switched system in which the transmission of the system states and switching signal are threatened by the DoS attack is further improved,the attacker and the controller are directly selected as the two players in a game model.According to the sequence of information transmission in the control system,the switched competition process between the attacker and controller is modeled as the switched Stackelberg game.The optimal leadership strategy and the optimal follower strategy are obtained respectively according to its Stackelberg equilibrium solution.Considering the open loop and asynchronous switching cases caused by attacker,sufficient conditions for mean square exponential stability of networked switched systems are obtained by using the mode-dependent average dwell time method.