Resilient Control For Cyber-physical Systems Under Denial-of-Service Attacks

In the past few years,due to the rapid development of communication technology,researchers have great interest in the research of the Cyber Physical System(CPS).CPSs integrate cyber space and physical world through making the most of control,computation and communication.It is for this reason that their applications are immense.As modern control systems begin to interconnect with the Internet,security issues frequently occur;In CPSs,attacks can in fact cause disruptions that transcend the cyber realm and affect the physical world,the loss can be irreparable.At the same time,people have a strong demand for systems’ security and reliability.Therefore,the safety of CPS has been widely concerned by researchers.Therefore,this paper studies the problem of resilient control under denial of service attacks.The main contents of this article are as follows:First of all,the problem of resilient control under two channels(sensor-to-controller and controller-to-actuator)asynchronous denial-of-service(DoS)attacks is considered,sufficient conditions for the observer-based control system are given such that the system is stable in the presence of DoS attacks which only limit time and frequency;Different from the existing papers where only consider the DoS attacks on the S-C channel,the coupling problem for the two interconnected channels under asynchronous DoS attacks is solved in this paper.Then,based on the property that the dwell-time of DoS is bounded,an interval partition technique is introduced to reduce the conservatism of stability analysis so that we can achieve the desired effect;in addition,through the simulations,it is found that due to the introduction of this new interval partition technique,CPSs with multi-transmission channels can tolerate more DoS attacks than before.Finally,different from the existing static output feedback controller,in this thesis,an observer-based controller design strategy is provided to improve the resilience against DoS.A sufficient condition for the desired observer-based controller such that the system is stable in the presence of DoS is provided in terms of linear matrix inequalities(LMIs),moreover,based on proposed conditions,a resilient observer-based controller design strategy is provided to improve the resilience against DoS.A numerical example is given to show that more intensive DoS attacks can be tolerant by the proposed interval partition technique and observer-based controller.