A Cable-Driven Parallel Robot With An Embedded Tilt-Roll Wrist

Abstract

This paper addresses the optimum design, configuration, and workspace analysis of a cable-driven parallel robot (CDPR) with an embedded tilt-roll wrist. The manipulator consists in a tilt-roll wrist mounted on the moving platform of a suspended CDPR. The embedded wrist provides large amplitudes of tilt and roll rotations and a large translational workspace obtained by the CDPR. This manipulator is suitable for tasks requiring large rotation and translation workspaces such as tomography scanning, camera-orienting devices, and visual surveillance. The moving-platform is an eight-degree-of-freedom articulated mechanism with large translational and rotational workspaces, and it is suspended from a fixed frame by six cables. The manipulator employs two bi-actuated cables, i.e., cable-loops to transmit the power from motors fixed on the ground to the tilt-roll wrist. Therefore, the manipulator achieves better dynamic performances due to a lower inertia of its moving-platform.

A Cable-Driven Parallel Robot With Full-Circle End-Effector Rotations

“…From Eqs. (17) to (19), the omni-wheel torque vector τ is expressed as a function of the cable tensions as follows:…”

“…1: CDPR with full-circle end-effector rotations loop for remote actuation of an embedded hoist mechanism on the moving platform. In [19], a moving-platform embedding a two-DOF differential gear set mechanism is presented allowing the two-DOF unlimited rotational motions of the end-effector. Thanks to cable-loops (bi-actuated cables), the embedded mechanisms are actuated by transmitting power through cables from motors, which are fixed on the ground, to the moving platform [20].…”

“…Thanks to cable-loops (bi-actuated cables), the embedded mechanisms are actuated by transmitting power through cables from motors, which are fixed on the ground, to the moving platform [20]. Therefore, by remote actuation through cable-loops, the tethering of the power cable to the moving platform is eliminated [21]. Moreover, a lower mass and a lower inertia of the moving platform are obtained due to the remote actuators.…”

A Cable-Driven Parallel Robot With Full-Circle End-Effector Rotations

“…In [10] a hybrid CDPR uses a cable-loop for remote actuation of an embedded hoist mechanism on the moving platform. In [11] a moving platform embedding a two-DOFs differential gear set mechanism is presented allowing the two-DOFs unlimited rotational motions of the end-effector. Thanks to cable-loops (bi-actuated cables), the embedded mechanisms are actuated by transmitting power through cables from motors, which are fixed on the ground, to the moving platform.…”

“…Thanks to cable-loops (bi-actuated cables), the embedded mechanisms are actuated by transmitting power through cables from motors, which are fixed on the ground, to the moving platform. Therefore, by remote actuation through cable-loops, the tethering of the power cable to the moving platform is eliminated [12]. Moreover, a lower mass and a lower inertia of the moving platform are obtained due to the remote actuators.…”