Coupled Cartesian Manipulators

Abstract

A new family of parallel mechanisms is synthesized and analyzed. The mechanisms couple identical Cartesian manipulator limbs together to a common moving-platform through two orthogonal revolute RR joints. Mechanisms with two limbs have hybrid serial-parallel topology, with up to five degrees-of-freedom (5-DOF) consisting of three translations and two rotations (3T2R). Mechanisms with four limbs are fully parallel with a single active prismatic joint per limb and 4-DOF 2T2R motion-type. An active moving base, connected in parallel, extends the motion to 5-DOF 3T2R motion-type. The topology of the parallel mechanism family allows a) positioning and orientating a moving-platform over a large workspace and b) readily implementing practical mechanisms using commercially available mechanical components. Background of comparable parallel Cartesian mechanisms provides context for the reported mechanism family. Schematics, solid model drawings and digital simulations illustrate the mechanisms’ topologies and motion. Derived kinematic equations provide the mathematical framework to analyze the properties of the mechanisms in terms of isotropy, decoupling, singularity, workspace and parasitic motion. The paper reports a) the new family of mechanisms, b) the topological methods to construct and analyze them and c) examples that illustrate the application prospects of the mechanism family in practical engineering.