On the full-spin dexterous orientation workspace of spherical parallel robots of 3-RRR-type

Abstract

This paper highlights the use of graphical techniques for workspace characterisation of spherical parallel robotic manipulators (SPRMs). Kinematic analysis of this type of mechanism is revisited through a 3D representation of the orientation operational space in a spherical coordinate system in which the radial coordinate corresponds to the last rotation of the Z-Y-X Euler angles sequence. The full-spin orientation workspace (FSOW) is defined as the region attainable for any spin rotation, third rotation around X, of the mobile platform (MPF). This new type of workspace can be considered as a dexterous workspace for SPRMs. A geometric approach, enabling efficient and rapid determination and representation of the FSOW, is introduced. Several examples are given to illustrate the implementation of the proposed method in a CAD environment.