Design-validation of a hand exoskeleton using musculoskeletal modeling

Abstract

Exoskeletons are progressively reaching homes and workplaces, allowing interaction with virtual environments, remote control of robots, or assisting human operators in carrying heavy loads. Their design is however still a challenge as these robots, being mechanically linked to the operators who wear them, have to meet ergonomic constraints besides usual robotic requirements in terms of workspace, speed, or efforts. They have in particular to fit the anthropometry and mobility of their users. This traditionally results in numerous prototypes which are progressively fitted to each individual person. In this paper, we propose instead to validate the design of a hand exoskeleton in a fully digital environment, without the need for a physical prototype. The purpose of this study is thus to examine whether finger kinematics are altered when using a given hand exoskeleton. Therefore, user specific musculoskeletal models were created and driven by a motion capture system to evaluate the fingers' joint kinematics when performing two industrial related tasks. The kinematic chain of the exoskeleton was added to the musculoskeletal models and its compliance with the hand movements was evaluated. Our results show that the proposed exoskeleton design does not influence fingers' joints angles, the coefficient of determination between the model with and without exoskeleton being consistently high (R¯=0.93) and the nRMSE consistently low (nRMSE¯ = 5.42°). These results are promising and this approach combining musculoskeletal and robotic modeling driven by motion capture data could be a key factor in the ergonomics validation of the design of orthotic devices and exoskeletons prior to manufacturing.

Design and development of the sEMG-based exoskeleton strength enhancer for the legs

“…The development of exoskeleton size depends on anthropometry [51] i.e., the physical measure of human size. For the proposed design, the leg to body height ratio of 49 % with respect to the average male size of 175 cm is considered.…”

Effects of Joint Assistance on the Muscle Metabolism and Strength in Different States Based on Simulation

“…Physiological simulation has been widely used to supply reference for the design of exoskeleton [28][29][30][31][32]. The joint angle, torque and muscle strength are able to be analyzed with musculoskeletal model [33][34][35].…”

The Effects on Muscle Activity and Discomfort of Varying Load Carriage With and Without an Augmentation Exoskeleton

“…Actual and virtual experiments in assessing the performance of the exoskeletons have already been undertaken [15,16]. In order to investigate the ergonomic performance of the augmentation exoskeleton developed by Southwest Jiaotong University, the effects on subjective discomfort and objective leg muscle activity are studied by a series of actual load carrying tasks.…”