Investigation of the stresses exerted by an exosuit of a human arm - Archive ouverte HAL Access content directly
Book Sections Year : 2020

Investigation of the stresses exerted by an exosuit of a human arm

Abstract

If a wheelchair could be considered as a better solution than an exoskeleton for the mobility of people suffering from neuromuscular diseases, there is a relevance to use a soft wearable exoskeleton (or exosuit) to assist the upper limbs in order to perform daily tasks such as having a drink, a pencil. It is imperative to limit the stresses generated by the exosuit on human. Numerical tests are proposed to investigate the possible technology choices to design the exoskeleton to limit these stresses. These numerical tests are based on the study of the inverse dynamic model of the human arm and its exosuit. A trajectory of the hand is defined and we deduce the cable tension to track this trajectory. Two decoupled planes are considered for the numerical tests, the sagittal plane where a flexion of the forearm with respect to the upper arm, and the frontal plane where abduction and adduction movements are possible. We assume that the human arm cannot provide any effort. The results show that the position of the anchor points at the shoulder and the orientation of the cable for the abduction movement have an influence to limit the stresses. However, these stresses are important on the shoulder. Nomenclature • m i (kg) (i = 1, 2): masses of the upper arm and forearm. • I i (kg.m 2) (i = 1, 2): inertia moments of the upper arm and forearm. • ℓ i (m) (i = 1, 2): lengths of the upper arm and forearm. • s u (m): position of the center of mass of the upper arm with respect the shoulder joint. • s f (m): position of the center of mass of the forearm with respect the shoulder joint. • s i (m) (i = 1, 2, 3): distances between the revolute joint and anchors and attachement point, respectively for the arm and forearm. • d 1 (m) is the height of the anchor and attachement points on the arm. • d 2 (m) is the height of the anchor and attachement points on the shoulder. • t i (N) (i = 1, 2, 3): cable tension. • g = 9.81 m.s −2 : Gravity constant.
Fichier principal
Vignette du fichier
YAITR2019.pdf (1.44 Mo) Télécharger le fichier
Origin Files produced by the author(s)
Loading...

Dates and versions

hal-02365461 , version 1 (15-11-2019)

Identifiers

  • HAL Id : hal-02365461 , version 1

Cite

Morgan Langard, Yannick Aoustin, Vigen Arakelian, Damien Chablat. Investigation of the stresses exerted by an exosuit of a human arm. Advanced Technologies in Robotics and Intelligent Systems, Mechanisms and Machine Science 80., 2020. ⟨hal-02365461⟩
105 View
242 Download

Share

Gmail Mastodon Facebook X LinkedIn More