Research On Control For Networked Systems Under Complex Attacks

Networked control systems(NCSs)are complex systems that integrate sensors,controllers,actuators and networks.Compared with traditional control systems,networked control systems show many unique advantages,such as flexible architecture,low installation and maintenance costs,and efficient data transmission efficiency.Therefore,networked control systems have been widely used in many fields,such as traffic management,robot control,mobile sensor network,remote surgery,unmanned aerial vehicles and remote control.However,in practical applications,due to the sharing characteristics of the network,especially the strong openness of the Internet and wireless networks,the data of sensors or controller exchanged through the network is suffered from network attacks and resource constraints,which further destroys the stability of the systems.Therefore,how to ensure the safety operation of networked control systems has important theoretical value and practical significance,when attacks occur or resources are limited.Up to now,most of the researches on networked control systems assume that the network operates in an ideal environment or that the network attack mode is relatively single,and the complexity of the attack is not fully considered.Therefore,the control problem of networked control systems under complex network attacks is studied in this thesis.The complex attacks in this thesis mainly include two types: complex attacks with complex attack forms and mixed attacks with multiple attacks.The main research contents are as follows:(1)The first chapter introduces the background of networked system,and then expounds the research significance of networked system under complex attacks.Then it introduces the research status of networked systems under complex attacks.Finally,it introduces the main work and structure of the article,as well as the source of the subject.(2)The second chapter introduces the important definitions and related lemmas needed to study the control problem of networked systems under complex attacks,and also introduces the important tool needed to analyze the control problem of networked systems under complex attacks – linear matrix inequality(LMI).(3)In Chapter 3,the control problem of uncertain networked systems with actuator saturation and spoofing attacks is studied.Firstly,the system is modeled.Assuming that the considered spoofing attack is a false data injection attack and the occurrence of the attack follows the Bernoulli distribution,the attack signal is modeled as a bounded nonlinear function,and the system is modeled as a random nonlinear system.In order to solve the problem of resource constraints,event triggering mechanism is introduced to reduce the pressure of network bandwidth and improve the efficiency of data communication.Finally,the system is established as a time-delay stochastic nonlinear system model.Then Lyapunov stability theory and stochastic analysis method are used to analyze the stability of the system,and linear matrix inequality is solved to design the feedback gain of the controller.Finally,the effectiveness of the algorithm is verified by numerical simulation.(4)In Chapter 4,the control problem of networked systems under mixed attacks is studied.Firstly,the system is modeled.Assuming that the hybrid attack includes denial of service attack and false data injection attack,the false data injection attack signal is modeled as a bounded nonlinear function,and the occurrence of the attack obeys Bernoulli distribution.At the same time,the denial of service attack considers periodic denial of service attack,so the system is modeled as a switching system.In order to solve the problem of resource constraints,event triggering mechanism is introduced to reduce the pressure of network bandwidth and improve the efficiency of data communication.Finally,the system is established as a delay switching system model.Then the stability of the system is analyzed by using Lyapunov stability theory and switched system analysis method,and the feedback gain of the controller is designed by solving linear matrix inequality.Finally,the effectiveness of the algorithm is verified by numerical simulation.(5)In Chapter 5,the control problem of uncertain networked systems based on hybridtriggered mechanism under false data injection attack is studied.Firstly,the system is modeled.Assuming that the considered spoofing attack is a false data injection attack and the occurrence of the attack follows the Bernoulli distribution,the attack signal is modeled as a bounded nonlinear function,and the system is modeled as a random nonlinear system.In order to solve the resource constrained problem,a hybrid-triggered mechanism is introduced to reduce the network bandwidth pressure and improve the data communication efficiency.Finally,the system is established as a time-delay stochastic system model.Then Lyapunov stability theory and stochastic analysis method are used to analyze the stability of the system,and linear matrix inequality is solved to design the feedback gain of the controller.Finally,the effectiveness of the algorithm is verified by numerical simulation.