Event-Triggered Fixed-Time Adaptive Fuzzy Control for Nontriangular Nonlinear Systems With Unknown Control Directions

This article focuses on the problem of fixed-time adaptive fuzzy control for a class of nontriangular nonlinear systems with unknown control directions under the event-triggered framework. To tackle the algebraic loop issue arising from the nontriangular structure, the property of the fuzzy logic system is employed. The command filter and the error compensation signals, which have the feature of fixed-time convergence, are constructed to eliminate the 'explosion of complexity' phenomenon and the effect of filtered error, respectively. By integrating the Nussbaum gain technique into the relative threshold-based event-triggered mechanism, a singularity-free fixed-time adaptive fuzzy control scheme is devised to ensure that the closed-loop system is practically fixed-time stable, and the tracking error converges to a small region near the origin in a fixed time. Finally, simulation examples are presented to demonstrate the effectiveness and superiority of the proposed fixed-time control algorithm. © 2020 IEEE.