Observer-Based Event-Triggered Control For A Class Of Networked Control Systems Under Denial Of Service Attacks

At present,in order to solve the problems of large amount of calculation and frequent occupation of network resources in networked control systems,scholars have proposed many different event-triggered schemes,which makes event-triggered control an effective solution in networked control systems with limited resources.It is worth noting that most of the research results at present have not considered the related problems of network malicious attacks.Therefore,it is of great academic value and practical significance to study the event-triggered control of networked control systems under a class of denial-of-service attacks.Based on two different event-triggered mechanisms,this thesis studies the system control of networked control systems under denial-of-service attacks.The main work can be summarized as the following two aspects:Firstly,this thesis studies the observer-based control problem of continuous linear networked control systems under denial-of-service attacks.In order to reduce sampling times and achieve the goal of effectively updating control signals,a new flexible event-triggered control strategy is designed based on the assumption that denial-of-service attacks interfere with the network frequency and consume bandwidth.Considering the influence of denial-of-service attacks on the event-triggered state,the maximum system performance loss is also calculated.Then,using Lyapunov functional method,the stability conditions of the system under no denialof-service attacks and denial-of-service attacks are given.The design of the controller here is given in the form of linear matrix inequalities.Finally,the theoretical results are verified by a simulation example.Secondly,this thesis studies the observer-based control problem of continuous linear networked control systems under intermittent denial-of-service attacks.In order to improve the communication efficiency,switching-like event-triggered control strategy based on observer is designed under the assumption that the denial-of-service attacks are a power-constrained and periodic interference signal,and we consider the maximum number of continuous packet losses in the system.By dividing Do S attacks into S-interval(without Do S)and D-interval(with Do S)and using Lyapunov stability theory,a lemma of asymptotic stability of the system without denial-of-service attacks is given.Then,based on this lemma,we obtain the stability conclusion of the event-triggered strategy based on switching-like event-triggered control with denial-ofservice attacks.The relationship between the two premeter in the event-triggered strategy are calculated here.At the same time,the calculation methods of controller gain and observer gain which meet the stability conditions are given.Finally,a numerical simulation example is given to verify the effectiveness of the conclusion.