Security Control Of Cyber Physical System In Strict Feedback Form Under FDI Attack

Cyber-Physical System(CPS)is a new generation system that deeply integrates computing,communication and control.It is characterized by the close integration of embedded computing,network and controlled physical processes,and is used in intelligent transportation,industrial production and other fields,which promotes the development of intelligence in all walks of life.Because of its powerful function and good future development prospects,its security becomes very important,and the increasingly open characteristics of CPS also brings security risks.False Data Injection(FDI)attack is a common type of security threats,easier to achieve than other attacks,and due to its high threat and strong destructive ability,security control research on this attack has attracted much attention in recent years.Therefore,the object of this study is CPS attacked by FDI.The main content of this paper is as follows:(1)For nonlinear strict feedback system,a fast terminal sliding mode control method based on backstepping method is proposed considering the actuator under FDI attack(hereinafter referred to as actuator FDI attack)when the parameters are known and there is no external disturbance.Firstly,several independent sliding mode surfaces are designed to ensure the convergence of sliding mode surfaces in finite time.Secondly,the controller is designed by using the backstepping method combined with the nonlinear differentiator family to ensure that the system can achieve sliding mode surfaces in a certain time when attacked,and avoid the problem of calculation explosion in the design process.Finally,the stability of the closed-loop system is proved based on Lyapunov stability theory.(2)Aiming at the strict feedback CPS with external disturbance and unknown nonlinear function,a security control scheme is proposed by combining backstepping method and super-twisting sliding mode control under the premise that the actuator is attacked by FDI.Firstly,a Radial Basis Function(RBF)neural network is used to approximate the unknown nonlinear terms in CPS.Secondly,the backstepping method is combined with the super-twisting sliding mode algorithm to eliminate the influence of the actuator attack and improve the robustness of the control system.Finally,based on Lyapunov stability theory,it is proved that the proposed security control scheme can ensure that all signals in the closed-loop system are semi-global and finally uniformly bounded.(3)For nonlinear strict feedback systems attacked by actuator FDI,a sliding mode control scheme based on Robust Adaptive Dynamic Programming(RADP)is proposed.Therefore,a robust sliding mode surface based on RADP is designed.The approximate optimal control law of the nominal system is used to effectively control the original dynamic system through system transformation.Adaptive attack compensation method is used to deal with the attack and eliminate the impact of the attack and disturbance on the system.