6自由度弱耦合并联机构机型设计及其方法

METHODOLOGY FOR TYPE SYNTHE-SIS OF KINEMATIC STRUCTURES OF 6-DOF WEAKLY-COUPLED PARALLEL MECHANISMS

提出了基于混合单开链的6自由度弱耦合并联机器人机构机型设计的一种程式化有效新方法,系统地阐述了动平台可实现三平移及三转动输出的6自由度并联机器人机构机型设计过程。设计出输出构件可实现三平移及三转动的7个新的实用混合单开链,首次给出静平台上6个转动副(或6个移动副)为主动副、具有较低耦合度及某些拓扑结构对称性的27种新的基本机型。通过改变主动副类型、主动副位置或支链的局部结构等又可得到更多的衍生机型。又按照机构拓扑结构对称性、输入—输出运动耦合复杂性、结构简单性及制造装配性能等对基本机型进行了简明分类并推荐了优选机型。

Based on basic structure theory of parallel robotic mechanisms, a novel type synthesis methodology for kinematic structures of 6-DOF weakly-coupled parallel mechanisms is presented, which considerates the hybrid chain as the 'limps' connecting the moving platform with the base. The 27 promis-ing 6-DOF parallel kinematic structures with lower coupling degree between independent loops, actuated by 6 rotation joints (or 6 prismatic joints) amounted at the base, are presented originally , the platform of which can possesses general spatial motions, i.e. three translations and three rotations. The much more alternatives to these kinematic structures also could be obtained by altering the location and the type of the driving joints or by changing some partial sub-structures relevant to the branch loops. The classification of these parallel kinematic structures is identified according to the four structure evaluation criteria suggested here, i.e.(a)structure topological symmetry; (b)coupling degree value between independent loops; (c) struc-ture simplicity (with fewer links and fewer joints); (d ) manu-facturability, from which optimal 6-DOF parallel kinematic structures are recommended in terms of different design re-quirements.