Practical prescribed-time output tracking control of uncertain nonaffine systems with input saturation based on time base generator

Abstract

To enhance adaptability in practical applications, active disturbance rejection control is extended to uncertain nonaffine systems with input saturation, achieving practical prescribed-time tracking control that drives the error to a sufficiently small neighborhood within a user-defined settling time. Based on a time-varying function called time base generators (TBG), a more general practical prescribed-time (PPT) nonlinear extended state observer (NLESO) is designed to estimate unknown states and total uncertainties while effectively suppressing peaking phenomena. By utilizing the PPT NLESO outputs, a TBG-based saturation control law is constructed to achieve PPT output tracking and address the nonaffine-in-control problem. The local PPT convergence of the closed-loop system under low-level input saturation is proved in a new paradigm. The numerical simulation and semi-physical simulation on the F-16 aircraft demonstrate the efficacy and superiority of the proposed method.