Predefined-time adaptive fuzzy control for nonlinear systems with input saturation and deferred restriction

This paper concentrates upon the predefined-time adaptive fuzzy tracking control issue of strict-feedback nonlinear systems subject to input saturation and deferred restriction. On account of intrinsic physical constraints and performance demands, input saturation and deferred restriction are common problems in engineering systems. To tackle 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-error-dependence function is created to work out the issue of deferred restriction. Combining backstepping technology with predefined-time stability theorem, a 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.