Abstract: A novel 3T1R parallel manipulator 2RRPaR+2RSS synthesized was proposed based on the topological structure design theory and method of POC equation. The structural analysis was described, the DOF and the POC set of the mechanisms were calculated, and proving that the coupling degree is equal to 2. According to the structural characteristics of the mechanisms and the constraint conditions of the bar, the forward kinematics was established by two-dimensional search method, the inverse kinematics was derived, and the correctness of them was verified. Then, based on the inverse kinematics, the 3D model of the workspace of the mechanisms was calculated by MATLAB programming, and a group of section shapes of different sections in Z direction were obtained. Meanwhile, the rotation ability was analyzed at the section where Z=1000 mm. Finally, the singularities of the mechanisms were analyzed based on Jacobian matrix. The results show that when the main dimensional parameters are the same, the working performances of the proposed 2RRPaR+2RSS parallel manipulator are superior than that of H4 mechanism. Compared with H4 mechanism, the workspace and rotation capability of the proposed parallel manipulator are increased by 27.87% and 4.35% respectively.

Key words: parallel manipulator, position and orientation characteristic(POC) set, kinematics, three-translation and one-rotation(3T1R), numerical solution method

摘要： 基于方位特征（POC）方程的并联机构拓扑结构设计理论与方法，提出了一种能实现三平移一转动（3T1R）的2RRPaR+2RSS并联操作手机构。对该机构进行了结构特性分析，计算了其自由度及POC集，并得出其耦合度为2；依据该机构的结构特性及几何约束条件，采用二维搜索法对该机构的位置正解进行了求解，推导出了其位置逆解，并验证了位置正逆解的正确性；基于该机构的逆解公式，计算出其三维工作空间，并得到了一组Z向不同截面的切片形状，同时对Z=1000 mm截面处的转动能力进行了分析；最后，基于雅可比矩阵对机构奇异位形进行了分析。研究结果表明：所提2RRPaR+2RSS机构在与H4机构主要尺寸参数相同的情况下，其工作性能总体优于H4机构。与H4机构相比，所提机构的工作空间增加了27.87%，其转动能力提高了4.35%。

关键词: 并联操作手, 方位特征集, 运动学, 三平移一转动, 数值法