A Light-Weight Cable-Driven Anthropomorphic Manipulator: Decoupling Design, Kinematics Modeling and Stiffness Analysis

Beyond pick-place and quasi-static manipulation, robots are increasingly expected to perform more interactive and dynamic tasks in our daily life. However, it is still very challenging for the traditional manipulator because of its high stiffness and large mass/inertia. To address the above issues, this letter presents a 7 DOF light-weight cable-driven anthropomorphic manipulator (CDAM) with the following characteristics. First, three kinds of cable decoupling mechanisms are designed based on the principle of movable pulley, which enables the actuator distribution of shoulder, elbow joints close to the base and the actuator distribution of wrist joint close to the elbow. Owing to the cable-driven decoupling design, the CDAM has a overall mass (without the fixed base) of only 5.5 kg, a maximum speed of 7.2 m/s, a maximum end acceleration around 31 m/s² and a maximum payload of 4 kg. Furthermore, the kinematics and stiffness model of the CDAM are established, while an efficient analytical solution of inverse kinematics exists owing to the decoupling and compact sphere-revolute-sphere (SRS) configuration design. Several experiments, including decoupling accuracy, positioning accuracy, repeatability, trajectory tracking, payload and speed tests, are carried out to validate the performance of CDAM.