Adaptive Fuzzy Fixed-Time Control for Uncertain Time-Delay Nonlinear Systems With Output Constraints

This paper aims to address two complex issues in the control of a class of high-order time-delay nonlinear systems: i) the adaptive fixed-time tracking control and ii) the differential explosion arising from the iterative derivation of the intermediate control law during the design process. The issue is how to construct a tracking controller to ensure that the tracking error converges to an adjustable region around the origin in a fixed time. This article develops an adaptive fixed-time control strategy by employing fuzzy logic system (FLS) to approximate the unknown function terms and the nonlinear growth assumption often used in unknown systems is eliminated. This strategy combines the dynamic surface technology with the first-order filtered signals in recursive design, and effectively addresses the sticky problem of complexity explosion in controller design. Finally, the effectiveness and feasibility of this control scheme are demonstrated through a single-link manipulator system and a numerical example