Research On Security Control Of Cyber Physical System Under Complex Cyber Attacks

With the rapid development of control theory and network communication technology,information space and physical space are highly integrated.Cyber Physical Systems(CPS),integrates sensing,communication,computing,and control,emerged as the times require.CPS is a kind of intelligent system that organically combines sensing and control capabilities,computing capabilities,communication capabilities,interaction between the physical world and the network,and intelligent control and adjustment capabilities.While information systems accomplish remote data interactive transmission and real-time control,due to the increasingly open nature of communication networks,the system will face many threats and challenges.For example,during data transmission,malicious network attacks such as Denial of Service(Do S),False Data Injection(FDI),and replay attacks will occur outside the system.Do S attacks disrupt packet data to prevent the normal transmission of sampled or control signals,FDI attacks destroy the authenticity and integrity of information by tampering with and injecting malicious data,and replay attacks can seriously affect system performance by maliciously duplicating or delaying transmitted data.In addition,due to the limited bandwidth of communication network,network induced communication constraints such as network delay,data packet loss,and external disturbances will inevitably occur.In such a framework,the security control problem is investigated for the CPS subject to complex cybter attacks and communication constraints.The main research contents are as follows:Firstly,the H_∞robust control problem is investigated for the CPS with time delays under Do S attack.Considering the impact of Do S attacks on the controller-actuator side,a Bernoulli random distributed cyber-attack model is established,and a class of uncertain networked system model is established for the case of time delay is less than one sampling period.Sufficient conditions for H_∞robust stability of CPS are derived by utilizing Lyapunov stability theory,and a state feedback controller satisfying H_∞robust performance is provided.The correctness and effectiveness of the proposed control method are verified by numerical simulation.Secondly,the H_∞robust output feedback control problem is investigated for the CPS under mixed network attacks.Considering the Do S and FDI attacks on the controller-actuator side,a hybrid cyber-attack model subject to Bernoulli random distribution is established,and a discrete event triggered communication mechanism is used to effectively save network bandwidth and improve network resource utilization.Based on this,the networked system model with multiple constraints is established,and sufficient conditions for H_∞robust stability of CPS are derived by utilizing Lyapunov stability theory.An output feedback controller satisfying H_∞robust performance is provided,thereby achieving co-design of control strategies and discrete event triggering schemes.The correctness and effectiveness of the proposed method are verified by an example simulation.Thirdly,the security control problem of dynamic output feedback is investigated for the CPS of under mixed network attacks.In order to describe the mixed cyber attacks suffered by the system,a random Do S attack model with energy constrained signal-to-noise ratio,and an FDI attack model with Bernoulli random distribution are used to establish an asynchronous dynamic switching CPS model.Sufficient conditions are derived for the asymptotic stability of asynchronous dynamic switched systems,and corresponding safety dynamic output feedback controllers are provided to implement the security control of CPS.A numerical example is used to verify the correctness and effectiveness of the proposed control method.Finally,a brief summary of the research results is given,and the future research directions are prospected.