Super‐Twisting Nonsingular Terminal Sliding Mode‐Based Robust Impedance Control of Robots

Abstract

This paper proposes a super‐twisting terminal sliding mode‐based robust impedance controller to improve the compliance and robustness in robot‐environment interaction. Based on the desired impedance dynamics, an impedance reference trajectory is constructed. Then, based on a super‐twisting terminal sliding‐mode, the robust impedance controller is designed to guarantee the achievement of the desired impedance dynamics in finite‐time through the finite‐time convergence of an impedance error. The main contribution of this paper is that the proposed control improves impedance control robustness by using the super‐twisting nonsingular terminal sliding‐mode without causing the chattering problem. The finite‐time stability of the closed‐loop control system is validated by theoretical analysis based on the Lyapunov theory, and the control effectiveness is illustrated by simulations on a two‐link robot manipulator.