The Control Problem Of Nonlinear Stochastic Time-delay System

In recent years,nonlinear time-delay and unmolded dynamics are commonly encountered in real systems.The problems of controller design and stability analysis of stochastic nonlinear large-scale systems have obtained rich theoretical results and extensive practical applications.In this paper,for two classes of nonlinear stochastic systems with different structure,controller design and stability analysis are investigated.The main contributions include: 1?Decentralized robust adaptive output-feedback control for a class of large-scale stochastic time-delay nonlinear systems with dynamic interactionsThe paper solves the problem of decentralized robust adaptive output-feedback control for a class of large-scale stochastic time-delay nonlinear systems.Under the assumptions that the inverse dynamics of the subsystems are stochastic input-to-state stable,an adaptive output-feedback controller is constructively designed by the back-stepping method.It is shown that under some milder conditions,the closed-loop system is globally stable in probability and the outputs can be regulated to an arbitrarily small neighborhood of the origin in probability and other signals in the closed-loop system are global bounded in probability by selecting the design parameters and appropriate Lyapunov function.A simulation example is presented to illustrate the effectiveness of the designed controller.2?Decentralized adaptive tracking control for high-order interconnected stochastic nonlinear time-varying delay systems with SISS inverse dynamics by neural networksThe paper solves the problem of a decentralized adaptive state-feedback neural tracking control for a class of stochastic nonlinear high-order interconnected systems.Under the assumptions that the inverse dynamics of the subsystems are stochastic input-to-state stable(SISS)and for the controller design,RBF neural networks are used to cope with the packaged unknown system dynamics and stochastic uncertainties.Besides,the appropriate Lyapunov-Krosovskii functions and parameters are constructed for a class of large-scale high-order stochastic nonlinear strong interconnected systems with inverse dynamics.It has been proved that the actual controller can be designed so as to guarantee that all the signals in the closed-loop systems remain semi-globally uniformly ultimately bounded(SGUUB),and the tracking errors eventually converge in the small neighborhood of origin.Simulation example has been proposed to show the effectiveness of our results.