【摘要】 设计了一种可实现整周回转运动且便于模块化装配的3T1R并联机构。首先,提出一种仅含转动副的二维移动放缩单元,模块化组合与扩展后,构造得到一种平面二维移动放缩机构,将平面二维移动放缩机构作为支链,设计得到一种新型3T1R并联机构;其次,对该3T1R机构进行拓扑结构分析,在保证机构基本功能(方位特征集和自由度)不变的情况下对其进行降耦设计,得到耦合度为1的机构;最后,基于序单开链法对降耦机构进行位置分析,同时,基于导出的机构位置反解公式,分析机构的工作空间和转动能力,并绘制转动能力图谱,根据转动能力图谱筛选出机构可实现整周回转运动的工作空间范围,为该型机构的设计和实际工程应用提供理论依据。更多还原

【Abstract】 There is a wide range of industrial application for the 4-DOF parallel mechanism( PM) which can achieve SCARA type output motion( i. e.,three translations and one rotation). However,due to the constraints of kinematic chains,most of them have small rotational capacity and cannot meet the actual demand sometimes. A type of 3T1R PM which can realize full cycle rotary motion was proposed. Firstly,a two-dimensional moving unit which consisted of revolute joint only was constructed. According to the mechanisms and machine theory,modular principle of the pantograph mechanism for scaling twodimensional planar graph was explained as the mechanism can be divided into three types of modules which were all derived from the two-dimensional moving unit. And then a 3T1R PM with four legs was designed by taking the obtained pantograph mechanisms as sub-chains. Secondly,the structure couplingreducing optimization design for this PM was performed,whose POC and DOF were unchanged with lower coupling degree( k = 1). Finally,the modeling method and the numerical solutions for forward and inverse position equations of the PM were established based on ordered single-open-chain( SOC) units.The working space and the rotational ability of this parallel mechanism were obtained and the rotational capacity map was drawn by using the inverse position equations. According to the map,the range of workspace that can realize the full rotational capability was selected which can be treated as a theoretical basis for the design and applications for this mechanism.更多还原