KINEMATIC DESIGN OF 5-DOF HYBRID ROBOT WITH LARGE

WORKSPACE/LIMB-STROKE RATIO

LIU Haitao¹  HUANG Tian¹  CHETWYND D G ²  LI Meng³  HU S J ³

(1．School of Mechanical Engineering, Tianjin University, Tianjin 300072;
2．School of Engineering, University of Warwick, Coventry CV47AL, UK;
3．Department of Mechanical Engineering, University of Michigan, Ann Arbor MI48109, USA )

Abstract: The conceptual design and dimensional synthesis of a novel 5-DOF reconfigurable hybrid robot module are presented. The module is composed of a 2-DOF parallel spherical mechanism which is serially connected with a 3-DOF open loop kinematic chain by a prismatic joint. The merit of this design is that a relatively large workspace/limb-stroke ratio can be achieved due to the decomposition of the fixed point rotation and the relative translation. The proposed 5-DOF hybrid robot can be employed as a plug-and-play module to configure different machines for the circumstances where high-speed yet light payload is required. The singularity and isotropy of the 2-DOF spherical parallel mechanism are analyzed based on the velocity mapping function. The dimensional synthesis of the 2-DOF spherical parallel mechanism is carried out with a goal to maximize the mean value of the minimum singular value of the Jacobian matrix in the workspace subject to a set of appropriate mechanical constraints. The results of the optimal kinematic design are given via examples.

Key words: Parallel robot Reconfigurability Conceptual design Dimensional synthesis

CLC No: TG156

国家自然科学基金(50375106, 50328506, 50510488, 50535010)和天津市科技攻关(043103711)资助项目. Received 20061122, received in revised form 20070209