Research On Robust Detection And Estimation Of Cyber Attacks In Cyber-Physical Systems

Cyber-physical Systems(CPSs)can realize highly integrated interaction between computing units and physical objects in cyberspace,and are widely used in intelligent transportation systems,smart power grids and other fields.However,due to the openness of the network,the CPS is vulnerable to malicious cyber attacks,especially the key national infrastructure,which seriously affects the stability of the social economy.Therefore,it is very important to enhance the security,robustness and reliability of CPS.Aiming at the above problem,this thesis studies the robust detection and estimation method of cyber attack in CPS.The main research content of this thesis is as follows:(1)Aiming at the attack detection problem of CPS with external disturbance,measurement noise and False Data Injection(FDI)attack,a robust attack detector based on H＿/H∞ was designed.Firstly,based on the influence of external disturbance and measurement noise on the system,the CPS under the false data injection attack is modeled.Then,a robust attack detector based on H＿/H∞ is designed,and the stability of the dynamic attack detection system is proved.The H＿index and H ∞ index represent the sensitivity to attack and the robustness to disturbance and measurement noise,respectively.Secondly,a residual evaluation function with a finite time window and an adaptive threshold with compensatory term are constructed to realize attack detection.Finally,numerical simulation and three-area power system simulation demonstrate the effectiveness and superiority of the proposed method.(2)Aiming at the attack estimation of interconnected cyber-physical systems with external disturbance and FDI attacks,a distributed attack estimator based on state reconfiguration is designed.Firstly,the communication topology of interconnected CPS is introduced.Then,the interconnected CPS subjected to FDI attacks is modeled.Secondly,a set of distributed attack estimators based on state reconfiguration is designed to estimate the FDI attacks on the system.The estimation of the attack and a set of distributed output feedback controller are used to compensate the loss of system performance caused by cyber attacks,so that the system can maintain stability.Finally,the effectiveness and superiority of the proposed method are verified by numerical simulation and the simulation of airspace unmanned aerial vehicle system in the crossdomain system.(3)Aiming at the problem of hybrid attack detection for interconnected cyberphysical systems with external disturbance and false data injection attacks,a distributed observer based attack detection method is proposed.Firstly,the interconnected nonlinear cyber-physical system with control signal and measurement signal under false data injection attack is modeled.Then,a distributed observer is designed to estimate the hybrid attack signals and implement attack detection.Finally,the effectiveness of the proposed method is verified by the simulation analysis of the unmanned vehicle fleet system in the cross-domain system.