A Robust Model Free Terminal Sliding Mode with Gravity Compensation Control of a 2 DoF Exoskeleton-Upper Limb System

[摘要] This paper presents a new robust model free terminal sliding mode (MFTSM) with gravity compensation approach used to control an exoskeleton-upper limb system. The considered system is a 2 DoF robot in interaction with an upper limb. It is used for rehabilitation to control the flexion/extension movement of the shoulder and the elbow joints in the presence of disturbances. In the first part, we present the exoskeleton-upper limb system modeling. Then, we controlled the considered system by the model free terminal sliding mode with and without gravity compensation. A stability study is realized. To prove the controllers performance, a robustness analysis was needed. The simulation results demonstrate that the MFTSMC over performs the terminal sliding mode and the model free controllers in terms of performance, robustness and disturbance rejection and that the gravity compensation improved the efficiency of the system when tracking the desired trajectories.

[学科分类] 自动化工程

[关键词] Exoskeleton-upper limb system;Model free terminal sliding mode;Gravity compensation;Robustness analysis;Monte Carlo simulation;Unmatched uncertainties