Wrist model for the whole human hand

Abstract

A hand with 25 degrees of freedom (DOF) was proposed with forward and inverse kinematics for all fingers, with a realistic virtual simulation. However, the wrist is not in the model. Today, several authors have proposed in the literature that the wrist has a relative movement between the two rows of bones with eight bones. Some authors discuss a comparison of four joint coordinate systems previously described in the literature. Others propose a helical movement of wrist bones in distal movements. Objective: A new design the hand model of 25 DOF adding a movement of two rows and eight bones of the wrist. Methods: Once we locate a new coordinates system in the end of the radius close to the scaphoid, we apply Denavit-Hartenberg for all joints. Forward and inverse kinematics are applied. We include ten ligaments to apply restrictions in the wrist movement, which affects fingertip position. Results: A new model of a virtual human hand with more accuracy is presented and validated with a Cyberglove™ and Leap Motion. Conclusions: This new model that includes wrist movement yields a more accurate virtual human hand. New DOFs are added to the 25-DOF hand model.