Delay-estimation-based adaptive fuzzy memory control for a class of uncertain nonlinear time-delay systems

This paper is concerned with the problem of adaptive fuzzy memory control for a class of uncertain nonlinear systems with unknown time delays. Compared with the existing results, the restrictions on the time-delayed functions are overcome, and the unknown delay parameters are estimated by establishing the piecewise adaptive laws. Based on the delay estimations and the backstepping technique, a novel adaptive fuzzy memory output feedback controller is designed. For the analysis of stability, the cubic Lyapunov functions with absolute value are constructed. It is proved that the proposed control scheme can guarantee that all the signals in the closed-loop system are bounded and the tracking error converges to a small neighborhood of the origin. Two practical simulation examples are given to demonstrate the effectiveness of the proposed control scheme.