Systematic evaluation of a knee exoskeleton misalignment compensation mechanism using a robotic dummy leg

“© 20XX IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”
The objective and quantitative assessment of physical human-exoskeletons interaction (pHEI) represents a pressing necessity in the wearable robots field. This process remains of difficult execution, especially for early stage devices, in which the inclusion of human testing could pose ethical and safety concerns. This manuscript proposes a methodology for pHEI assessment based on an active dummy leg named Leg Replica, which is able to sense interaction forces while wearing an exoskeleton. We tested this methodology on a wearable active knee exoskeleton prototype, with the goal to evaluate the effects of a misalignment compensation mechanism. Through this methodology, it was possible to show how the misalignment compensation mechanism was able to reduce the interaction forces during passive exoskeleton motion. Such reduction was less evident when the exoskeleton was active. The tests allowed to identify specific points of improvements for the exoskeleton, enabling a more specific upgrade of the device based on these experimental results. This study demonstrates the ability of the proposed methodology to objectively benchmark different aspects of pHEI, and to accelerate the iterative development of new devices prior to human testing.
This work was supported by the project EXOSAFE, awarded by the COVR European Project under grant agreement No. 779966. The exoskeleton prototype used in this work was developed with funding received from the European Union’s Horizon2020 research and innovation programme under Marie Skłodowska-Curie grant agreement No. 801342(Tecniospring INDUSTRY) and the Government of Catalonia’s Agency for Business Competitiveness (ACCIÓ).
Peer Reviewed
Postprint (author's final draft)