Systematic usability evaluation on two harnesses for a wearable chairless exoskeleton

Abstract

Harnesses are used in wearable robots in safety, sports, medical, and industrial environments. Wearable robot harnesses for lower extremities should be designed to prevent musculoskeletal disorders caused by excessive strain on the spine and lower extremities when users wear these robots for prolonged periods. Therefore, this study compares and analyzes the usability of the two harnesses—the former (old design) and the latter (new design)—for the Hyundai chairless exoskeleton (CEX). In total, 27 participants took part in this study. The wearability, stability, and overall wearing satisfaction of the former and the latter harnesses were compared. We conducted an experiment where the participants wore the former and the latter harnesses while completing a series of tasks that resembled the ones performed by the workers on a front-end module assembling line of an automobile factory. After the experiment, the participants took part in a survey and semi-structured interviews. The data was analyses by t-test, correlation, and regression analyses. The survey results demonstrated that for the latter harness the cushioning sensation (thigh r = 0.539; calf r = 0.516) had the strongest effect on the overall wearing satisfaction. In addition, the latter harness scored higher in overall wear satisfaction than the previous harness. This study was able to verify the difference between the new and old designs according to the usability evaluation of the harness. The results of this study are considered to be helpful in design to improve the usability of the harness in the future.