Evaluating reachable workspace and user control over prehensor aperture for a body-powered prosthesis

Chadwell, AEA; Kenney, LPJ; Howard, D; Ssekitoleko, RT; Nakandi, BT; Head, JS

Abstract

Using a shoulder harness and control cable, a
person can control the opening and closing of a bodypowered prosthesis prehensor. In many setups the cable
does not pass adjacent to the shoulder joint center allowing
shoulder flexion on the prosthetic side to be used for
prehensor control. However, this makes cable setup a
difficult compromise as prosthesis control is dependent on
arm posture; too short and the space within which a person
can reach may be unduly restricted, too long and the user
may not be able to move their shoulder sufficiently to take
up the inevitable slack at some postures and hence have no
control over prehensor movement. Despite the fundamental
importance of reachable workspace to users, to date there
have been no studies in prosthetics on this aspect. Here, a
methodology is presented to quantify the reduction in the
reachable volume due to the harness, and to record the
range-of-motion of the prehensor at a series of locations
within the reachable workspace. Ten anatomically intact
participants were assessed using a body-powered prosthesis
simulator. Data was collected using a 3D motion capture
system and an electronic goniometer. The harnessed
reachable workspace was 38-85% the size of the
unharnessed volume with participants struggling to reach
across the body and above the head. Across all arm postures
assessed, participants were only able to achieve full
prehensor range-of-motion in 9%. The methodologies
presented could be used to evaluate future designs of both
body-powered and myoelectric prostheses.

Citation

Chadwell, A., Kenney, L., Howard, D., Ssekitoleko, R., Nakandi, B., & Head, J. (2020). Evaluating reachable workspace and user control over prehensor aperture for a body-powered prosthesis. IEEE Transactions on Neural Systems and Rehabilitation Engineering, 28(9), 2005-2014. https://doi.org/10.1109/TNSRE.2020.3010625

• Journal Article Type: Article
• Acceptance Date: Jul 16, 2020
• Online Publication Date: Jul 20, 2020
• Publication Date: Sep 1, 2020
• Deposit Date: Jul 28, 2020
• Publicly Available Date: Jul 28, 2020
• Journal: IEEE Transactions on Neural Systems and Rehabilitation Engineering
• Print ISSN: 1534-4320
• Electronic ISSN: 1558-0210
• Publisher: Institute of Electrical and Electronics Engineers
• Volume: 28
• Issue: 9
• Pages: 2005-2014
• DOI: https://doi.org/10.1109/TNSRE.2020.3010625
• Publisher URL: https://doi.org/10.1109/TNSRE.2020.3010625
• Related Public URLs: http://ieeexplore.ieee.org/xpl/RecentIssue.jsp/?punumber=7333
• Additional Information: Funders : Engineering and Physical Sciences Research Council (EPSRC);National Institute for Health Research (NIHR); Grant Number: EP/R013985/1