KINEMATIC PERFORMANCE ANALYSIS OF 3-DOF PARALLEL MECHANISM WITH LARGE

POSITIONAL WORKSPACE

LI Jianfeng  FEI Renyuan  FAN Jinhong  WU Guangzhong

(College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing 100022 )

Abstract: A 3-DOF parallel mechanism with large positional workspace is proposed, which is a varietal type of the Tricept mechanism. The structural characteristic of the presented mechanism is that the passive sub-chain of Tricept mechanism is integrated into one of its three active sub-chains, and the three axes of active joints are perpendicular to each other and intersect one point. The positional workspace, kinematic dexterity and stiffness property of the mechanism are analyzed, The graphic descriptions of the relationships between performance changes of mechanism versus the varieties of its dimensional parameters are presented. The analysis shows that for mechanisms with different dimensional parameter combinations and smaller limitative angles of universal and spherical joints, the movable platforms can obtain large positional workspaces. In addition, the mid-regions hold larger proportion of volume values of the positional workspaces, and the movable platforms have better dexterity and stiffness in mid-regions. The graphic descriptions acquired illuminate the relationships between kinematic performance and mechanism’s dimensional parameters fully and can be applied to further characteristic analysis and kinematic design of mechanisms.

Key words: 2PUS-PU parallel mechanism Large positional workspace Dexterity Stiffness

CLC No: TH112.1

国家自然科学基金(60275031)和北京市先进制造技术重点实验室开放基金(KP0100200201)资助项目. Received 20060817, received in revised form 20070422