Assessing joint angles in human hand via optical tracking device and calibrating instrumented glove

Abstract

The aim of this paper is to present a method for assessing joint angles in a human hand: a method suitable for the calibration of an instrumented glove. The method is based on an optical tracking device and an inverse-kinematic model of the human hand. It requires only one reflective marker to be attached to each finger and three on the dorsal aspect of the hand in order to assess angles in finger joints. A further three markers are needed to calculate angles in thumb joints. Joint angles assessed through inverse kinematics and with the calibrated glove were validated against reference angles calculated from the centers of rotation of the joints while measuring the finger movements with multiple markers. In fingers, the mean difference between the reference angles and the angles assessed by the glove did not exceed ±7° when the proposed model-based method was used to calibrate the glove. For the thumb the mean error did not exceed ±5° when the reference method was used to calibrate the glove.