Development of Upper-Limb Power-Assist Machine Using Linkage Mechanism – Mechanism and its Fundamental Motion –

This paper proposes an upper-limb power-assist machine that is driven by a single actuator to reduce its weight and cost. The assist machine is intended for supporting shoulder and elbow movements during work in the field of viticulture. It consists of an arm part, a mounting part, and a drive part, the last of which contains an actuator and a worm gear. The arm part is equipped with a parallel link mechanism. In order to realize natural upper-limb motion, the length of the arm part is designed on the basis of human upper-limb motion. The assist machine is controlled by user intention through the use of bending sensors attached to the input device. The assistance effectiveness of the proposed assist machine is verified experimentally by measuring the EMG signals of the deltoid, biceps brachii, and triceps brachii muscles.