Abstract
This paper develops a novel robotic joint mechanism having a pair of polyurethane round-belts, which are placed on both sides around the joint. This mechanism is based on antagonistic configuration by the round-belts activated by twisting motion by means of individual DC motors. This novel mechanism enables the robotic joint to move around its axis due to contraction forces induced by twisting both the round-belts. Next, this paper proposes a contraction force model by comparing with experimental force measurement, in which we estimated Young's modulus satisfying linearly decreasing manner with respect to twist rotation. In addition, we measure contact forces exerted on the tip of a single link robot, and compare with theoretical values obtained from the contraction force model formulated in this paper. Finally, we show validity of the proposed model, and conclude that estimated contact force is worth enough to be employed on force feedback system even in force sensorless configurations.
