The effects of target location on temporal coordination of the upper body during 3D seated reaches considering the range of motion

• Published in: International journal of industrial ergonomics Vol. 34; no. 5; pp. 395 - 405
• Main Authors: Lim, Sunghyun, Martin, Bernard J., Chung, Min K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2004
• Subjects: Digital human model; Inter-joint delay; Range of motion; Seated reach behavior; Temporal coordination; Range of motion; Temporal coordination; Inter-joint delay; Seated reach behavior; Digital human model
• ISSN: 0169-8141; 1872-8219
• DOI: 10.1016/j.ergon.2004.05.002

The objective of this study was to investigate the effects of target location on the temporal coordination of the upper body in 3D seated reaches over an extensive range of motion. Sixteen subjects reached to 64 targets distributed in the right hemisphere over four azimuths, with four heights and four radial distances from the right shoulder. The results showed that (1) all the joints did not start to move simultaneously (2) they did not stop their movements in synchrony (3) inter joint delays were significantly influenced by target location (4) tangential velocity profiles of the hand were also affected by target location. The results can be applied to develop a new seated reach prediction model that takes inter joint delays into account and simulate more natural and realistic seated reach motions. Such model can be applied to evaluate and develop products and workplaces more effectively. In order to evaluate products and workplaces more efficiently, digital human models have been an absolute need to reduce development cost and implement pro-active ergonomics. Among the many ergonomic evaluations, reach analysis has been one of the most important applications of digital human models since this activity is present in all industrial tasks requiring human operation. This study deals with seated reach behavior characteristics considering the three-dimensional range of motion.