Design and Control of a Seven Degrees of Freedom Manipulator Actuated by a Coupled Tendon-Drive System

A seven degrees of freedom manipulator actuated by a tendon-drive system has been developed. In order to reduce the weight and volume of the manipulator, each actuator was installed on the base frame, and the actuator torque was transmitted to each joint through a tendon pulley system. The tendon-drive mechanism, which uses a coupled drive, actuates the manipulator by controlling the tension of each tendon. In the developed system, eight direct-drive motors and tendon pulleys were used for a seven degrees of freedom manipulator. In this paper, the structure of the manipulator developed is first explained. Then, the tendon-tension-based control method for the coupled drive manipulator is formulated. Finally, through simple experiments using the manipulator in which the control system was installed, the effectiveness of the proposed structure and the control method is demonstrated.