Safety Controller Synthesis Of Interval Type-2 T-S Model-based Networked Systems

The network control system can be regarded as a complex nonlinear system,and fuzzy control can effectively deal with such complex nonlinear models.Therefore,fuzzy control is a powerful tool for analyzing network control systems.The T-S model is a global model which can be formed by connecting a group of linear sub-models in terms of nonlinear fuzzy weights.It can approximate any smooth nonlinear function with any precision in any compact set.However,in a highly uncertain environment,the type-1 fuzzy model often cannot achieve better results,and the type-2 fuzzy model can handle this situation.The interval type-2 fuzzy set not only retains the advantages of the type-2 fuzzy set in dealing with uncertainties of membership functions,but also can reduce the burden of computation for type-2 fuzzy set.Therefore,the interval type-2 fuzzy set has more practical application value.Network control systems generally have the characteristics of time delay and uncertainty,and are easy to suffer network attacks,especially Do S(Denial of Service)attack,which are the main factors that cause system instability.Therefore,investigating the network control system with time delay,uncertainty and network attacks to improve network system performance have great development prospects and practical application value.Based on the interval type-2 T-S model,this thesis mainly discusses the controller design of fuzzy network systems under Do S attack.The research content of this thesis mainly contains the following three parts:The first part: The controller design problem of a class of network systems based on the interval type-2 T-S model is investigated when the system under consideration is subjected to Do S attack.Selecting appropriate Lyapunov-Krasovskii functionals,comprehensively applying Jensen inequality,convex combination and free weight matrix methods,together with the existing methods of dealing with Do S attack,a security controller based on the interval type-2T-S fuzzy model network system is designed,and get a larger upper bound of the time delay.A simulation example verifies the effectiveness of the design method.The second part: The controller design problem of a class of interval type-2 T-S model network system with both state time delay and network-induced time delay is investigated when the considered system is subjected to Do S attack.Choose an augmented Lyapunov-Krasovskii functional with triple integral terms.Utilize this Lyapunov-Krasovskii functional,the integral inequality of the free weight matrix,Jensen double integral inequality,and adopting the method of dealing with Do S attack in the above part,the sufficient conditions and controllers that enable the system to maintain security performance under Do S attack are obtained.The third part: The controller design problem of a class of interval type-2 fuzzy network systems with dual time delays and uncertain parameters is studied when the system under consideration is subjected to Do S attack.Utilizing matrix factorization to handle the parameter uncertainties,together with Lyapunov-Krasovskii functional,inequality scaling techniques and the methods in dealing with Do S attack,the controller is designed and it can keep the closedloop network system safe.