Gross Motion and Classification of Manipulators with Closed-Loop, Four-Bar Chains

Abstract

This article presents an extensive study on the gross motion of 2-DOF manipulators with closed-loop, four-bar chains. The investigation is focused on (1) classification, (2) work space and sub-work space, (3) existence of singular circles, (4) number of postures and service angles, and (5) the effects of the orientation of the wrist on the floating link. One may find that closed-loop manipulators are not only lightweight, they can also provide better kinematic properties in view of work space, singularity, postures, and service angles.