Observer-based fuzzy adaptive control for stochastic nonlinear time-varying delay systems with unknown control directions

This paper discussed the problem of adaptive fuzzy output-feedback tracking control for a class of stochastic nonlinear systems with time-varying delay. With the help of a state observer and an appropriate stochastic Lyapunov-Krasovskii functional, an adaptive fuzzy tracking controller is developed, which ensures the boundedness of all the closed-loop signals and the convergence of the tracking error to a small neighborhood of the origin. A simulation example is given to illustrate the effectiveness of the proposed approach.