Design of Power Assist Manipulator for Exoskeleton Robot using Scissor-hinge Structure

Abstract

The handwork systems that have traditionally been used in many fields have been replaced with industrial and special purpose robots. However, the use of these robots is restricted for use in work places in which workers perform simple, repetitive tasks. Therefore, a great deal of research has been conducted on the advantages HRI in complex industrial fields. Exoskeleton robots that can be worn incorporate human movements and the mechanical power of robots. In particular, lower limb exoskeleton robots move intuitively and are ideal to assist the muscles. This paper presents the design of a lower limb attachable manipulator that supports movements in the upper limbs. First, convertible mechanism was designed using a scissor-hinge structure. This mechanism folded and unfolded easily when in use. Second, the design of the links connecting a convertible mechanism to a hand lift mechanism was optimized. Finally, a 4-bar link hand lift was created. After the entire system was produced, the efficiency of the system was verified through an experiment in which muscle activity was measured using EMG sensors when lifting 5 kg. The results confirmed that the power assist manipulator alleviates muscle fatigue. The manipulator designed in this study rectified common issues with exoskeleton robots, such as their large size and substantial weight.