Branching tendon routing: A new tendon methodology for compact transmission

In this paper, we propose a new tendon routing method using branching tendon for driving a revolute joint. Unlike conventional tendon (or wire) widely used in the tendon transmission, the branching tendon splits into sub-tendons, and the end points of the sub-tendons are located on the same link but different positions. Thus, without using any complicated and bulky mechanism, the branching tendon can transmit the tendon force through the alternative path depending on the rotating angle of the joint. Based on this concept, the design of the branching tendon with two sub-tendons is proposed. Also, an analysis of the tension transmission path of this branching tendon is performed to increase force transmitting efficiency. By applying this branching tendon, a finger joint with a compact tendon routing path was constructed. And we have verified that the branching tendon can be used to develop robotic fingers or hand prosthetics.