Manipulability Analysis for Cable-Driven Hyper-Redundant Manipulators

Abstract

Cable-driven hyper-redundant manipulators (CDHMs) have been widely applied in aerospace, surgery, or other fields to complete tasks in narrow and multi-obstacles environments. Maneuverability is an important metric for CDHMs and is more difficult to analyze than traditional industrial robots because of their more complicated kinematics. So far, the proposed methods for evaluating the manipulability of cable-driven robots are similar to those of traditional industrial robots in that they focus on the joints and ignore the cables. However, these methods are flawed for cable-driven robots because they can t guarantee the dexterity of the true driving space (i.e., cable space). In this paper, a tailored analysis tool is proposed, which contains two core metrics, namely, cable velocity manipulability ellipsoid (CVME) and cable-driven cost index (CDCI), to evaluate CDHMs manipulability of cables, joints, and the end-effector. Firstly, the Jacobian matrix mapping from the end-effector velocity to the cable velocity is solved based on minimizing the norm of the cable velocity. Then the CVME and CDCI are defined through this Jacobian matrix. Finally, we show how to perform a specific analysis of the manipulability of CDHMs using CVME and CDCI. The simulation results demonstrate that the CVME and CDCI are reasonable and effective.