A nine-degree-of-freedom multijoint manipulator called the CT ARM-I has been developed. The CT ATM-I is based on the concept of coupled drive and the connected differential mechanism, and thus the force for lifting a payload does not concentrate on one actuator but is distributed among all actuators. This manipulator has a specific tendon traction force transmission mechanism in which a pair of tendons for driving a joint are pulled from base actuators via pulleys mounted on the base-side joints. The mechanism uses the coupled drive function of the tendon traction forces and thus enables the lightweight manipulator to exhibit high payload capability. Through the experimental study, it was demonstrated that the CT ARM-I has an active compliance arm and offers payload capability far superior to conventional designs.>

A coupled tendon-driven manipulator, CT arm, is presented. In its tendon traction force transmission mechanism, the pair of tendons driving a joint is pulled by base actuators via pulleys mounted on the base-side joints. The mechanism uses coupled drive function of the tendon traction forces and thus exhibits a large payload capability for such a light-weight manipulator arm. CT arm has a solid structure and can be manufactured inexpensively because of its mechanical simplicity. Through experimental simulation, it is known that CT arm has the structure of a variable compliance arm and has an unusually large payload capacity.>