Tension Control Method Utilizing Antagonistic Tension to Enlarge the Workspace of Coupled Tendon-Driven Articulated Manipulator

The exploration and inspection of narrow spaces in industrial plants require the use of long-reach redundant manipulators with large three-dimensional (3D) workspaces. To this end, in a previous work, a coupled tendon-driven articulated manipulator with a total length of 10 m and yaw joints for 3D motion was developed. This study focuses on employing the antagonistic tension in a yaw joint to support a tendon that drives a pitch joint with high gravitational loading. Herein, a tension control method that employs the antagonistic tension to reduces the amount of tension required to support the weight of an arm is proposed. The effectiveness of the proposed method is evaluated based on the workspace volume of the previously developed Super Dragon, and the results demonstrate that the proposed method expands the workspace by up to 45%.