Synthesis of 2-DOF spherical fully parallel mechanisms

Abstract

This paper deals with the synthesis of 2-dof spherical fully parallel mechanisms with legs of type US (U and S are for universal and spherical joints, respectively). First, two analytical methods derived from the literature are used to find the conditions for the legs to fit within the desired spherical relative motion between the base and the movable platform of the mechanism. Then, these conditions are used to devise three families of mechanisms which comprise also over-constrained architectures. Finally, actuation issues and kinematic, workspace and singularity analyses are addressed.