Research On Robust Stabilization And H_? Control For Stochastic Systems With Parameter Uncertainty And Nonlinearity

With the rapid development of science and technology in recent years,the research and application of control theory have achieved very significant theoretical and application results.Nowadays,the robust control of stochastic time-delay systems has become a hot topic in control theory.Many corresponding theories and methods have emerged in large numbers,which make many control problems studied and solved by scholars.At present,there are relatively few research results on uncertain stochastic nonlinear time-delay systems.In this paper,we study the stochastic time-delay nonlinear control system accordingly.First of all,for a class of uncertain stochastic nonlinear time-delay systems,this thesis studies its time-dependent robust stochastic stabilization problem and the corresponding H?control problem.Among them,the uncertain parameters are time-varying unknown and satisfy the norm bounded.The robust stability conditions of the corresponding system and linear matrix inequalities are obtained by using Ito formulas and corresponding matrix theory and the Lyapunov-Krasovskii functional method.Then the memoryless state feedback controller of the system is acquired to ensure the effectiveness of the system performance.This makes the system more general and the corresponding theoretical results less conservative.Finally,the validity and feasibility of the results are proved by giving corresponding numerical examples.After that,this thesis further studies the robust stability and stabilization of a class of discrete-time stochastic time-delay systems with parameter uncertainty and nonlinear perturbations.First,by constructing the appropriate Lyapunov-Krasovskii functional,we can use the correlation matrix inequality theory method to obtain the robust stochastic stability condition of the corresponding system,which is given as a linear matrix inequality.Then,based on the state feedback controller of the system,we obtain the discrete-time closed-loop system,and thus obtain the robust random stabilization conditions for a class of uncertain discrete-time stochastic systems,which are given in the form of linear matrix inequalities.The obtained controller gain can thus guarantee the robust random stability of the discrete-time closed-loop system.Finally,numerical examples are used to further verify the validity and feasibility of the results.