engleski

Estimation of hand preshaping during human grasping by using instrumented glove

This paper deals with the novel method for evaluating hand preshaping during reaching-to-grasp movement. The method makes use of all five fingers in estimation of prehension [1]. The investigation was performed on six healthy subjects grasping three different objects at various positions and orientations. The objects were presented to the subjects by means of a robot, which also induced perturbations in both object position and orientation. Positions of markers attached to the finger-tips and dorsum of the hand were recorded by means of a 3D optical tracking system, Optotrak. In the data analysis the adjacent finger-tips were interconnected, thus obtaining a planar pentagon whose various characteristics were investigated and discussed. New parameters for the evaluation of finger preshaping, such as pentagon surface area, angle between the pentagon and hand normal vectors, and the angle between the pentagon and object normal vectors between were introduced, [1]. We have also investigated the hand orientation during prehensile movements by analysing the angle between the vectors emanating from the palm and object to be grasped [2]. As the next step of improving the applicability of the method is the implementation of the instrumented glove. 3D optical motion tracking system is reliable, but robust and complicate to use, especially in the rehabilitation environment. On the other hand, the instrumented glove is easy to use, and, as we shoved, provides reliable data. We performed simultaneous measurement of prehensile movement by glove and Optotrak. We used biomechanical model of the hand to calculate the positions of the fingertips on the basis of the fingers joint angles measured by the glove. The data calculated from the glove outputs were compared with the markers positions recorded by Optotrak. So obtained data were used to calculate hand opening described by pentagon square area. The proposed pentagon approach is expected to be useful in future work when examining grasping abilities of subjects with neuromuscular disorders.

human grasping; instrumented glove; fingers trajectories

nije evidentirano