Design and Optimization of Cable-driven Servo-manipulator for Motion Decoupling

In this report, we investigated kinematic motion coupling problems where the length or tension of a cable is changed due to another link's motions and we also analyzed the conventional joint decoupling configurations for cable-driven manipulators. To maintain the cable length constant regardless of the rotation of the arm, we present a structural decoupling mechanism for a cable-driven manipulator. In case of an elbow joint design, we used a novel joint decoupling mechanism where a moving pulley which actively compensates for a motion interference. For a wrist joint design, we optimized the geometrical parameters of the cable-pulley configurations. As for a shoulder joint, we adopted motion decoupled structures where an upper arm a roll and forearm pitch motion are performed in a differential driving manner. Designed motion decoupled cable driven mechanism prevents an unintended malfunction of the manipulator, and it also increases the durability of the power transmission elements of the manipulator