Robust Control Design Using a Hybrid-Gain Finite-Time Sliding-Mode Controller

TL;DR

This paper introduces a hybrid-gain finite-time sliding-mode controller that ensures rapid, robust, and smooth control for perturbed nonlinear systems, including robotic manipulators, with explicit control effort limitations.

Contribution

It presents a novel hybrid-gain finite-time sliding-mode control strategy combining a boundary layer reaching law with an inner rapid convergence law, applicable to a broad class of systems.

Findings

Achieves finite-time convergence and robustness to disturbances.

Reduces control effort compared to recent finite-time methods.

Validates effectiveness through simulations on robotic systems.

Abstract

This paper proposes a hybrid-gain finite-time sliding-mode control (HG-FTSMC) strategy for a class of perturbed nonlinear systems. The controller combines a finite-time reaching law that drives the sliding variable to a predefined boundary layer with an inner mixed-power or exponential law that guarantees rapid convergence within the layer while maintaining smooth and bounded control action. The resulting control design achieves finite-time convergence and robustness to matched disturbances, while explicitly limits the control effort. The control framework is first analyzed on a perturbed first-order integrator model, and then extended to Euler-Lagrange (EL) systems, representing a broad class of robotic and mechanical systems. Comparative simulations demonstrate that the proposed controller achieves settling times comparable to recent finite-time approaches [1], while substantially reducing the control effort. Finally, trajectory-tracking simulations on a two-link manipulator further validate the robustness and practical feasibility of the proposed HG-FTSMC approach.