Design of a Lockable Spherical Joint for a Reconfigurable 3-URU Parallel Platform

Abstract

This article deals with the functional and preliminary design of a reconfigurable joint for robotic applications. Such mechanism is a key element for a class of lower mobility parallel manipulators, allowing a local reconfiguration of the kinematic chain that enables a change in platform’s mobility. The mechanism can be integrated in the kinematic structure of a 3-URU manipulator, which shall accordingly gain the ability to change mobility from pure translation to pure rotation. As a matter of fact, special kinematics conditions must be met for the accomplishment of this task. Such peculiar requirements are described and properly exploited for the design of an effective reconfigurable mechanism. A detailed description of the joint operational principle is provided, also showing how to design it when is physically located at the fixed base of the manipulator.

A Review of the Literature on the Lower-Mobility Parallel Manipulators of 3-UPU or 3-URU Type

“…Carbonari et al reconfigurable 3-URU [26]: Joint configurations A and B refer to the TPM and PW modes, respectively, the padlock denotes the locked R-pair, the darker R-pair is the actuated pair. Figure downloaded from [36] https://www.mdpi.com/2218-6581/7/3/42 and reproduced with the permission of the authors.…”

Control of a 3-RRR Planar Parallel Robot Using Fractional Order PID Controller

“…Furthermore, parallel manipulators can be utilized for applications that need high speed, accuracy, and stiffness [2] . Finally, a hybrid manipulator [3] can be constructed based on a combination of serial and parallel manipulators or multiple parallel manipulators connected in sequence. Other hybrid configurations can be created based on different industrial requirements.…”