Abstract: According to the theory and method of topological design for parallel mechanisms（PM） based on the position and orientation characteristic（POC） equations， a spatial two-translation and one revolution（2T1R） PM with zero coupling degree and partial motion decoupling was designed， which consisted of fully revolute pairs and a redundant actuated chain（RRR）. And the topological structure of the PM was analyzed. By the kinematics modeling principles based on topological characteristics， the symbolic forward kinematics was given. At the same time， the inverse kinematics was derived to obtain the Jacobian matrix of the moving platform， where the speed and acceleration of each link were derived. Finally， the ordered-single-open chain method was used for the inverse dynamic modeling and analysis of the PM based on the principle of virtual work proposed by the author team. The driving torques of the PM and the action forces of the kinematic pair were solved， which was then verified by ADAMS dynamics simulation. The study provides a technical basis for the design of the parallel pipe benders required for the tube bending machining. 

Key words: topological design, coupling degree, symbolic solution, principle of virtual work, ordered-single-open chain method

摘要： 根据基于方位特征（POC）方程的并联机构拓扑设计理论及方法，设计了一种含一条冗余驱动支链（RRR）、零耦合度且部分运动解耦的全转动副组成的空间两平移一转动（2T1R）并联机构，并对该机构进行了拓扑结构分析；依据基于拓扑特征的运动学建模原理，给出了该机构的符号式位置正解；同时推导出了位置逆解，得到了动平台的雅可比矩阵，由此推导出了机构内各构件的速度、加速度；最后，将笔者团队提出的基于虚功原理的序单开链法用于该空间机构的逆向动力学建模与分析，求解了机构的驱动力矩和若干重要运动副的支反力，并通过ADAMS软件予以动力学仿真验证。研究结果为该机构用作管材弯曲加工所需的并联弯管机设计提供了技术依据。

关键词: 拓扑设计, 耦合度, 符号解, 虚功原理, 序单开链法