Kinematic design of a six-DOF parallel-kinematics Machine with decoupled-motion architecture

• Published in: IEEE transactions on robotics Vol. 20; no. 5; pp. 876 - 887
• Main Authors: Guilin Yang, I-Ming Chen, Chen, W., Wei Lin
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2004; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Architecture; Assembly; Computer science; control theory; systems; Control theory. Systems; Design engineering; Drives; Exact sciences and technology; Horizontal; Kinematics; Kinetics; Leg; Legged locomotion; Legs; Linkage mechanisms, cams; Machining; Manipulators; Manufacturing; Mechanical engineering. Machine design; Mechatronics; Planes; Platforms; Prototypes; Robotics; Robots; Translations; Freedom degree; Linkage mechanism; Machining; Parallel mechanism; Rotation axis; Robotics; Workspace; Manipulator
• ISSN: 1552-3098; 1941-0468
• DOI: 10.1109/TRO.2004.829485

The design of a new six-degree-of-freedom (6-DOF) parallel-kinematics machine (PKM) has been proposed. Different from the conventional Stewart-Gough platform which has six extensible legs, the new PKM employs three identical RPRS legs to support the moving platform. Since all joint axes, excluding the three spherical joints at the leg ends, are parallel to each other and perpendicular to the base plane, this 6-DOF PKM presents a promising platform structure with decoupled-motion architecture (DMA) such that translation in a horizontal plane and rotation about a vertical axis are driven by the three active revolute joints, while translation in the vertical direction and rotation about horizontal axes are driven by the three active prismatic joints. As a result, this 6-DOF 3RPRS PKM with DMA has simple kinematics, large cylindrical reachable workspace, and high stiffness in the vertical direction. These features make it appropriate for light machining and heavy parts assembly tasks. Because of the DMA, a projection technique is employed for its kinematics analysis. By projecting the manipulator onto horizontal directions and vertical planes, the kinematics issues such as the displacement, singularity, and workspace analysis are significantly simplified.