An innovative equivalent kinematic model of the human upper limb to improve the trajectory planning of exoskeleton rehabilitation robots

Qiaolian Xie,Qiaoling Meng,Hongliu Yu,Zhijia Shen,Qingxin Zeng

doi:10.5194/ms-12-661-2021

Qiaolian Xie, Qiaoling Meng + Show 3 more

Open Access

https://doi.org/10.5194/ms-12-661-2021

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Abstract

Abstract. Upper limb exoskeleton rehabilitation robots have been attracting significant attention by researchers due to their adaptive training, highly repetitive motion, and ability to enhance the self-care capabilities of patients with disabilities. It is a key problem that the existing upper limb exoskeletons cannot stay in line with the corresponding human arm during exercise. The aim is to evaluate whether the existing upper limb exoskeleton movement is in line with the human movement and to provide a design basis for the future exoskeleton. This paper proposes a new equivalent kinematic model for human upper limb, including the shoulder joint, elbow joint, and wrist joint, according to the human anatomical structure and sports biomechanical characteristics. And this paper analyzes the motion space according to the normal range of motion of joints for building the workspace of the proposed model. Then, the trajectory planning for an upper limb exoskeleton is evaluated and improved based on the proposed model. The evaluation results show that there were obvious differences between the exoskeleton prototype and human arm. The deviation between the human body and the exoskeleton of the improved trajectory is decreased to 41.64 %. In conclusion, the new equivalent kinematics model for the human upper limb proposed in this paper can effectively evaluate the existing upper limb exoskeleton and provide suggestions for structural improvements in line with human motion.

Highlights

Upper limb exoskeleton rehabilitation robots have become more popular because they can provide adaptive training and highly repetitive motion and enhance the self-care capabilities of patients with a loss of motor function (Jarrasse et al, 2010; Côté-Allard et al, 2018; Zhang et al, 2018)
The number of degrees of freedom (DOF), range of motion (ROM) of joints, safety, comfort, low inertia, and adaptability to the human body should be especially considered in the design of these exoskeletons (Meng et al, 2018; Maciejasz et al, 2014)
This paper proposes a new, 13 DOF equivalent kinematic model that can more accurately describe the movement of the human upper limbs

Summary

Introduction

Upper limb exoskeleton rehabilitation robots have become more popular because they can provide adaptive training and highly repetitive motion and enhance the self-care capabilities of patients with a loss of motor function (Jarrasse et al, 2010; Côté-Allard et al, 2018; Zhang et al, 2018). The design of upper limb exoskeletons should be especially considered because they interact directly with the human body (Esmaeili et al, 2011; Gopura et al, 2011). The number of degrees of freedom (DOF), range of motion (ROM) of joints, safety, comfort, low inertia, and adaptability to the human body should be especially considered in the design of these exoskeletons (Meng et al, 2018; Maciejasz et al, 2014). It is necessary that the movement of the exoskeleton should stay in line with the human arm. The design of the upper limb exoskeleton is generally based on the movement of the human arm. The number of DOF is defined according to the shoulder joint, elbow

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