Title: Biomechanical investigation of a passive upper-extremity exoskeleton for manual material handling - a computational parameter study and modelling approach

Authors: Bo Eitel Seiferheld; Jeppe Frost; Mathias Krog; Sebastian Skals; Michael Skipper Andersen

Addresses: Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7D, 9220 Aalborg East, Denmark; Department of Materials and Production, Aalborg University, Fibigerstræde 16, 9220 Aalborg East, Denmark ' Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7D, 9220 Aalborg East, Denmark ' Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7D, 9220 Aalborg East, Denmark ' Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7D, 9220 Aalborg East, Denmark; Musculoskeletal Disorders and Physical Workload, National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen East, Denmark ' Department of Materials and Production, Aalborg University, Fibigerstræde 16, 9220 Aalborg East, Denmark

Abstract: Passive upper-extremity exoskeletons may decrease the risk of developing work-related musculoskeletal disorders. This study examined how shoulder muscle forces and biomechanical loads in the glenohumeral and L4-L5 joint changed as different support torque (1.1 Nm-11.2 Nm) and angle settings (60°-120°) of an exoskeleton were simulated during an overhead manual material handling task. Full-body kinematics of 15 grocery workers, who lifted a bread case (7.9 kg) onto shopping shelves (145.5 cm), were captured on site. The kinematic data were used to drive a detailed human-exoskeleton model based on inverse dynamics. Generally, simulations with maximum torque combined with a peak angle setting between 75°-105° reduced L4-L5 compression and anteroposterior shear forces, glenohumeral contact forces and shoulder flexor muscle forces. The exoskeleton therefore, seemed effective for reducing physical exposure during overhead handling. However, maximum torque with the lowest angle setting, 60°, increased musculoskeletal loading, suggesting that not adjusting the exoskeleton properly could be detrimental.

Keywords: musculoskeletal modelling; musculoskeletal diseases; exoskeleton device; lifting; manual material handling; MMH; computer simulation; biomechanics.

DOI: 10.1504/IJHFMS.2022.124304

International Journal of Human Factors Modelling and Simulation, 2022 Vol.7 No.3/4, pp.275 - 300

Received: 07 May 2021
Accepted: 20 Dec 2021
Published online: 21 Jul 2022 *