Elephant-inspired tapered cable-driven hyper-redundant manipulator: design and performance analysis

The cable-driven hyper-redundant manipulator (CDHM), distinguished by its high flexibility and adjustable stiffness, is extensively utilized in confined and obstacle-rich environments such as aerospace and nuclear facilities. This paper introduces a novel CDHM inspired by the trunk of elephants, which changes the arm structure from cylindrical to conical. This alteration diminishes the arm's self-weight, reduces the moment arm of gravity, decreases the volume of the end joint, narrows the stroke of the driving cables, and boosts the maximum joint speed of the manipulator. Additionally, this study examines the impact of the manipulator's taper on its overall performance from both dynamic and kinematic perspectives. Finally, three prototype manipulators with varying tapers are confirmed, and tests are conducted on each manipulator's motion performance and cable tension. By comparing experimental data, the accuracy of the theoretical analysis and the rationality of the conical structure are confirmed. The results suggest that the proposed new configuration offers certain advantages in terms of cable stroke, joint speed and maximum driving force.