Research On Co-Design Of Security Control And Communication For Cyber Physical System Under Cyber-Attacks

Cyber physical system(CPS)is an intelligent control system that realizes the close integration and coordination of computing resources and physical resources through the high integration of 3C that is computing,communication and control.It has been widely used in all aspects of modern society.However,with the rapid development of related technologies,CPS is more prone to failure of original devices and malicious cyber attacks due to the complexity and networking of its physical components.Once the system exposes to cyber attacks,the consequences are data loss and system shutdown.This will pose a serious threat to production and life and even national security.However,there are a few scholars to investigate the comprehensive security control problems about CPS that faults and attacks occur simultaneously in the existing literature.In addition,the effective use of CPS communication resources is also one of its research hotspots.Therefore,how to deal with the problems between security control and resource constraints for CPS in which physical faults coexist with cyber attacks is particularly important.And it has far-reaching scientific significance and extensive engineering value.In view of this,based on discrete event-triggered communication scheme(DETCS),this thesis investigates the collaborative design problem between security control and communication for CPS that actuator faults and cyber attacks occur simultaneously with the help of networked control system fault-tolerant control,using a fusion of active and passive approach.The details are as follows:1)Based on DETCS,security control system architecture for CPS fault tolerance and attack tolerance is proposed with the help of concept of edge computing.In the intelligent sensing unit under the constant physical sampling period and the control unit under the non-uniform transmission period,the online detection,estimation and feedback compensation of the states,attacks and faults are implemented with a distributed idea,which provides the possibility to realize the co-design of subsequent security control and communication.2)With the help of fault-tolerant control ideas and classification methods,a model of closed-loop CPS is established that integrates a triggering condition,actuator faults and cyber-attacks into a single uniform framework for three different research methods,which are passive fault tolerance/attack tolerance,active fault tolerance/passive attack tolerance and active fault tolerance/active-passive attack tolerance.The closed-loop CPS model lays the foundation for the subsequent online estimation of states,attacks and faults,and the collaborative acquirement of the security controller gain matrix and event triggering matrix.3)Focusing on different ways of dealing with cyber attacks and physical faults,three types of co-design problems between security control and communication,such as passive fault tolerance/attack tolerance,active fault tolerance/passive attack tolerance and active fault tolerance/active-passive attack tolerance,are studied.The sufficient conditions of CPS robust H_?fault tolerance/attack tolerance and the design method of security controller are derived.Then it achieves the goal of optimal balance between security control and resource constraint.4)By introducinga-stability constraint,adoptting the improved Wirtinger inequality,affine Bessel-Legendre inequality and other less conservative techniques not only reduces the conservativeness of CPS co-design methods between robust fault tolerance/attack tolerance control and communication,but also increases the solution space of positive definite symmetric matrix parameters that the observers and controllers in seeking.What's more,it improves the satisfaction between CPS security control system performance and the communication resource saving.