Security Control Of Network Control System Under Network Attack

Network control system is a closed-loop network control system that is fully distributed and can feedbacks system status in real time.System components(e.g.sensors,controllers,actuators,etc.)are connected through a shared network,so that control signals and feedbacks signals can be exchanged between devices.Compared with the traditional control system,the network control system eliminates the unnecessary wiring between the system components,and has the advantages of reducing the complexity and cost of the system and making it easy to expand the system.After more than 20 years of research and development,network control system has been applied in many fields,such as the automotive field,the intelligent transportation field,the smart grid field,etc.The introduction of the network has brought many benefits to the control system,but also given network hackers an opportunity.With the purpose of maliciously destroying the security and stability of the network control system,the attacker interferes with the normal network communication of the system,steals user privacy,and tampers with the communication data,resulting in the system being out of control or even paralyzed.The deep integration of cyberspace and physical space has made the security of network control systems attract more and more scholars’ attention,and it is of great significance to study the security problems of network control systems under network attacks.In this thesis,taking the network control system as the research object,studied the security control issues of the network control system under the replay attack,DoS attack,and deception attack,the specific research content is as follows:1)Studied the security control problem of discrete-time network control system under a type of replay attack.Assumed that when a system is subjected to a replay attack,the controller and actuator adopt the principle of keeping input,and the number of consecutive replay attacks on the system is bounded.Using the idea of switching system,the network control system under a replay attack was modeled as a switching system with a finite number of subsystems.A performance assurance state feedback controller was designed,and the average residence time method was used to obtain sufficient conditions for system index stability and give the performance level of the system.2)Studied the security control problem of discrete-time network control system under a type of DoS attack.Modeling the DoS attack into a random variable that conforms to Bernoulli’s distribution,an output feedback controller was designed to calculate the expectation of the difference of the Lyapunov function of the stochastic system,and obtained sufficient conditions for the stability of the stochastic system.3)Studied the security control problem of discrete-time network control system under a type of DoS attack and deception attack.The DoS attack and deception attack were modeled into two independent random variables that conform to Bernoulli distribution,a performanceguaranteed output feedback controller was designed,and the expectation of the difference of the system’s ISSi P-Lyapunov function was calculated to obtain sufficient conditions for system input-to-state stable with probability and gived the system’s performance level.