Dexterity measure of upper limb exoskeleton robot with improved redundancy

Abstract

Exoskeleton manipulators are used for different applications in robotic field. Human motion is highly complicated and flexible; therefore obtain human like motion from exoskeleton manipulator becomes a challenge to researches in this field. This paper presents an improvement of dexterity measure as a result of adding redundancy to upper limb exoskeleton manipulator. Proposed manipulator has four degree of freedom. This takes the effect of DOF at human elbow and wrist of the upper limb. Dexterity of the manipulator is measured using manipulability index and minimum singular value. All measures are based on Jacobian of the manipulator. This four DOF manipulator is then modified by adding two more degrees of freedom to make total of six. Therefore with respect to task defined in operational space; modified exoskeleton manipulator operates as redundant. Manipulability index and minimum singular value are again determined for six degree of freedom modified exoskeleton manipulator. The effect of redundancy in order to improve the manipulation in upper limb exoskeleton robot is investigated in this study.