Kinematic Compatible Elbow Exoskeletons with Static Balance

Abstract

The purpose of this paper is to propose a kinematic compatibility of exoskeleton suits for human limbs. The kinematic compatibility can eliminate discomfort caused by exoskeletons and make exoskeletons not only enable the users to perform motions but also does not cause discomfort to them. Discomfort is caused by the axial force and torque applying on the human limbs. To avoid discomfort, the relative motions between attached link of human limbs and exoskeleton has to be eliminated and the weight of human limbs and exoskeleton has to be balanced. By taking attached link of human limbs and exoskeleton as the same link, the relative motion is eliminated. To avoid axial force applying on human limbs, the weights of human limbs and exoskeleton have to respectively achieve static balancing. Human limbs performing its original motions is the set of operating dimensions and the DOF of exoskeletons should cover the human limbs. In this thesis, discussing the situation that the set of operating dimensions of exoskeleton is the same as the human limbs. Based on the above conditions, the number of exoskeleton joints for human limbs is obtained. By applying the kinematic compatibility to human limbs with two coplanar links and an axis perpendicular 1-R joint. For the human limbs, take elbow without carrying angle as application and verified whether the axial force approach to zero during the motions when both human limbs and exoskeleton achieve static balancing. If the axial force approaches to zero, it means the exoskeleton won’t cause discomfort to the users.