Finite-Time Disturbance Observer-based New Fast Terminal Sliding Mode Control for Systems with Uncertainties in Dynamics and Disturbances: Application to Three-DOF Hover Quadrotor

Abstract

This paper proposes a Finite-Time Disturbance Observer-based new Fast Terminal Sliding Mode Control (FTDO–FTSMC) for systems under disturbances and parametric uncertainties with input saturation. Our approach begins with the design of a finite-time observer to estimate disturbances, in which we show that the errors in disturbance estimation converge to zero in finite time. Then, a new fast terminal sliding surface is proposed for the fast and finite-time convergence of the tracking errors. The closed-loop system under the proposed control scheme has been proved to be asymptotically stable by using the Lyapunov theory. Finally, the proposed FTDO–FTSMC framework is applied to the attitude control of a three-DOF hover quadrotor under time-varying disturbances and parametric uncertainties. Simulation results show that the proposed control strategy achieves excellent performance in terms of trajectory tracking, disturbance rejection and robustness, even in the presence of external disturbances and model uncertainties, compared with the existing control approaches.