Research On Security Control Methods Of Stochastic Distribution Control Systems Under Cyber Attacks

With the rapid development of network communication technology,more and more industrial control systems are connected through different and open public networks,which makes industrial control systems face more and more risk of cyber attacks.In the face of the increasing network destructive behavior and the diversification of cyber attack tools,traditional network security protection means can not meet the actual needs of network development,and it is urgent to adopt new theories and research methods.As one of the usual Control models,studying Stochastic Distribution Control(SDC for short)systems has important theoretical and practical significance.From the perspective of systems security,this thesis studies the state,weight estimation and security control of SDC systems under cyber attacks.The purpose is to ensure that the systems can still accurately estimate the weight and state of the SDC systems under cyber attacks,and design the corresponding controller based on the estimated value to ensure that the output PDFs of the systems can track the desired output PDFs and ensure the overall stability of the systems.Although the research results on SDC systems have been relatively rich,and in addition to the research on some control algorithms,fault diagnosis(FD for short),fault estimation,fault isolation and fault tolerant control(FTC for short)methods have also been developed,but the modeling,estimation and control of SDC systems subject to cyber attacks have received little attention.Therefore,how to make SDC systems stable and keep the performance index from decreasing after cyber attacks becomes a necessary research topic in the field of control.In this thesis,linear system control theory,observer theory,PI(Propriotation Integration)controller,Model Predictive Control(MPC for short)controller,Lyapunov function analysis and other methods are used comprehensively.Aiming at the SDC systems under cyber attacks,the corresponding security state and weight estimation method is designed,and the corresponding observer is constructed,and several controllers are designed according to the estimated state and weight to solve the tracking problem of the systems output PDFs and the stability problem of the systems.The validity of the presented estimation algorithm and controller design algorithm is verified by Matlab simulation platform.The main work and innovations of this thesis are as follows:Firstly,for a class of SDC systems subject to sparse sensors attacks in discrete time,a sufficient condition for the solvable weight estimation is established.If sufficient conditions are met,the security measurement preselector is used to extract unattacked security output measurement vector,which is used to construct a discrete Luenberger weight observer to efficiently achieve the estimation of the system weights.Furthermore,a discrete augmented PI controller design scheme is proposed by using the systems weight error vector,weight estimation vector and controller gain vector,which realizes the tracking control problem of output PDFs and ensures the stability of the closed-loop systems.Secondly,a state estimation and resilient control scheme based on MPC algorithm is investigated for a class of T-S(Takagi-Sugeno)fuzzy SDC systems under sparse sensor attacks.A T-S fuzzy model is developed to describe the dynamics of the non-Gaussian SDC systems,and the state and attack signals in the systems are estimated using a fuzzy Luenberger observer.Based on the estimated states and attack signals,a MPC resilient control scheme is designed to achieve good tracking performance well and ensure the stability of the systems.Thirdly,for a class of linear SDC systems subject to actuator attacks,a Luenberger state observer and a resilient controller based on PI control strategy are proposed.First,a Luenberger state observer is proposed,which can effectively estimate the state and weight signal of the systems.Based on the estimated state signal,a new desired weight and an incremental PI control strategy based on the attack signals of the actuator are proposed.Then,the controller gain is determined by solving an inequality,which effectively ensures the stability of the closed-loop systems and enables the output PDFs of the systems to closely track the desired output PDFs.