Development of Upper-Limb Power Assist Machine Using Linkage Mechanism – Drive Mechanism and its Applications –

This paper proposes an upper-limb power assist machine driven by a single actuator to reduce the weight and cost. This assist machine is used to support the shoulder and elbow movements for viticulture operations, and upper-limb holding for load transport tasks. This assist machine consists of an arm part and a mounting part. The arm part is composed of a parallel link mechanism, which is driven by an actuator and a trapezoidal feed screw. To realize a natural upper-limb motion, the length of the arm part was designed based on the human upper-limb motion. The assist machine is controlled based on the user’s intention by applying bend sensors attached to the input device. By measuring the electromyography signal of five muscles, the effectiveness of the proposed upper-limb power assist machine was verified experimentally.