Predefined-Time Sliding Mode Control for Manipulators Based on Fully Actuated Systems

A predefined-time control strategy integrating a predefined-time nonlinear disturbance observer (PTNDO) and a predefined-time sliding mode controller (PTSMC) are developed to address model uncertainties and external disturbances in fully actuated systems. First, a PTNDO is designed to estimate the lumped disturbances, and the convergence of the disturbance estimation error is guaranteed within a predefined-time. Then, by exploiting the parametric characteristics of fully actuated systems (FAS), the control system is simplified. A PTSMC is constructed to drive the system states to the desired equilibrium in a predefined-time, independent of initial conditions. Lyapunov-based methods are used to establish to verify the predefined-time stability of the closed-loop system, with simulation results further confirming the theoretical analysis and the effectiveness of the proposed control scheme.