Estimation of Three Finger Joint Angle based on Relative Slide of Strings

Abstract

This paper presents the method for estimating three finger joints angle at the same time using four strings and three flexible layered belts. The method applied the difference of slide displacement of strings during finger flexion. The belt keeps the relative distance from the rotational center, and the relative displacement of strings is in proportion to the joints angle. Moreover, fixing the strings and belts step by step on the finger joint enables to estimate each joints angle simultaneously. The developed device realized the measurement of finger motion, although most of the similar devices require the calibration to identify the individual finger shape. We experimented on the device with the finger model to evaluate the accuracy of the estimation of finger movement. We validated that this system estimates each finger joints angle by about 5 degree on root-mean-square error (RMSE).