Skill Acquisition in Multi-Dimensional Manipulator Control

Abstract

Movements of a three-jointed electrically-powered manipulator were controlled by vertical movements of the second, third and fourth fingers of the subject's hand. Both two-dimensional and three-dimensional movement problems were examined. In the two-dimensional case, subjects were shown a silhouette of the manipulator with a lit endpoint or the manipulator endpoint alone. The manipulator was always fully visible in the three-dimensional case. Recordings were made of time-to-target, maximum deviation from a straight line path, and the percent of time that various numbers of controls were activated simultaneously. The results indicated that with practice the subjects tended to approach targets on a straight line course in both situations. They also increased the percentage of time that several controls were activated together. Being able to see the manipulator improved control coordination and decreased movement time in the two-dimensional case, but did not affect movement accuracy.