The reachable 3-D workspace volume is a measure of payload and body-mass-index: A quasi-static kinetic assessment

• Published in: Applied ergonomics Vol. 75; pp. 108 - 119
• Main Authors: Castro, Miguel Nobre, Rasmussen, John, Bai, Shaoping, Andersen, Michael Skipper
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2019
• Subjects: Adult; Body Mass Index; Elbow Joint; Ergonomics - methods; Hand - physiology; Humans; Interior Design and Furnishings - methods; Kinetics; Male; Movement; Range of Motion, Articular; Reachable workspace; Shoulder Joint - physiology; Statistical modelling; Strength measurements; Torso - physiology; Upper extremity kinematics; Workload - statistics & numerical data; Strength measurements; Reachable workspace; Upper extremity kinematics; Statistical modelling
• DOI: 10.1016/j.apergo.2018.09.010
• ISSN: 0003-6870; 1872-9126

An experimental protocol with five tasks is proposed for a low-cost empirical assessment of the reachable 3-D workspace (RWS), including both close-to-torso and far-from-torso regions. Ten participants repeated the protocol for four distinct hand payloads. The RWS expressed as a point cloud and its non-convex alpha-shape were obtained for each case. Moreover, individual strength surrogates for glenohumeral flexion and abduction, and elbow flexion were collected using a dynamometer. The RWS volume was statistically modelled using payload, body-mass-index and the strength surrogates as predictors. For increasing payload, a significant (r = −0.736,p < 0.001) decrease in RWS volume was found for distinct payload cases across all subjects. The only significant predictors found for the RWS volume were normalized payload (F = 73.740,p < 0.001) and body-mass-index (F = 11.008,p = 0.003). No significant interactions were found. The consequent regression model (F(2,27) = 41.11, p < 0.001, Radj2 = 0.7345) explained around 73% of the variation in the data. The RWS volume is a function of payload and body-mass-index. [Display omitted] •A new experimental protocol is proposed for assessing the reachable 3-D workspace.•Alpha-shapes enable retrieval of the non-convex shape of all reachable envelopes.•The reachable 3-D workspace volume inversely correlates to payload.•Payload and body-mass-index predicted 73% of the variation in the RWS volume.