Practical Predefined-Time Adaptive Fuzzy Control for Nonlinear Systems With Input Saturation and Deferred Restriction

Abstract This paper concentrates upon the practical predefined-time adaptive fuzzy tracking control issue of strict-feedback nonlinear systems subjected to input saturation and deferred restriction. On account of intrinsic physical constraints and performance demands, input saturation and deferred restriction are common problems in practical engineering systems. To solve these issues, a smooth function is utilized to estimate the actuator saturation, and then an improved auxiliary system is introduced to counterbalance the influence of input saturation. Moreover, the Lyapunov function incorporating the deferred-errordependence function is created to work out the issue of deferred restriction. Combining backstepping technology with practical predefined-time stability theorem, a practical predefined-time adaptive fuzzy control algorithm is constructed, under which the boundary of convergence time is capable of being arbitrarily set ahead of schedule by designers, such freedom can be used to improve the finite/fixed-time control results. Two simulation outcomes are offered to validate the usefulness of the control algorithm.