Measuring Anthopometric Fit for Exoskeletons: Methodologies and Preliminary Assessment

Abstract

Exoskeletons are becoming more common for industrial applications to relieve workers from physically demanding tasks. Even if researchers and ruling entities started to propose standard methodologies to test the exoskeleton's efficacy, this did not happen to test the physical match between users and exoskeletons that plays a central role in safety, efficiency and acceptance. This work presents methodologies (tools, metrics and testing protocols) to quantitatively measure static and dynamic fit of exoskeletons: measuring equipment ease (as a gap between device and body) and influence on biological joints' motion. In the end, the methodology is used on XoTrunk, a lower back occupational exoskeleton suited for Manual Material Handling activities, a laboratory test setup resemble relevant activities with voluntary subjects. Preliminary analysis in descriptive statistics suggests that the exoskeleton's attachments are not always adherent to users' body (4 cm maximum gap), are well aligned to body landmarks to comfortably unload assistance but move rubbing the sacrum area (6 cm drifts), thus lowering comfort and, ultimately, device acceptance. In the end, the proposed methodology succeed to measure all relevant data to evaluate static and dynamic fit. However, further metrics could be added when moving to a more realistic scenario, to improve the dynamic fit evaluation.