The Effects of Obstructions on Arm Movement Time during Reach and Positioning Movements of a Simulated Maintenance Task

Abstract

The purpose of this study was to investigate the fundamental issue of how an obstruction affects movement time during reach and positioning components of a simulated maintenance task. Eight obstruction locations for two target locations provided the experimental manipulation for the study, while movement time was measured as the dependent variable. Data for all the trials were obtained using a three-dimensional magnetic sensing device placed on the back of the subject's hand as he/she moved in space from the starting point to the target in a wooden mockup replicating the work space of a maintainer in an aircraft horizontal stabilizer. Results indicated that movement times increased when the vertical position of the obstruction was within roughly 5.72 cm of the target. Subjects' perceived difficulty in those conditions with longer movement times was attributable more to the inability to see the target during the end of the motion than the lack of positioning space around the target. These findings emphasize the role visual feedback played in a task of this type, and its effect on maintenance procedure times in general.

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