中文摘要：

1T2R三自由度并联机构具有1个移动自由度和2个转动自由度,应用十分广泛。如何从大量的1T2R三自由度并联机构构型中遴选出具有工程应用价值的机型,具有重要的实际意义。运用基于螺旋理论的运动/力传递性能指标对3-PRRU、2-PRU-PRRU和2-PRS-PRRU三种1T2R并联机构进行构型优选,这里P表示移动副,R表示转动副,U表示万向铰。根据三种机构的运动学反解建立输入运动螺旋、输出运动螺旋和分支力传递螺旋的解析式,计算出整个工作空间上的运动/力传递性能指标并绘制图谱。性能图谱显示三种1T2R并联机构都具有较好的运动/力传递特性,并且奇异边界相似,其中3-PRRU并联机构优质工作空间最大。

英文摘要：

A 3-DOF （degrees of freedom） 1T2R parallel mechanism has one translational （T） DOF and two rotational （R） DOFs and can be used in many applications. It is very important to select optimal architectures that have practical potentials from the large available number of 1T2R parallel mechanisms. Force/motion transmission index based on screw theory is used to perform optimal selection from three 1T2R parallel mechanism, namely, 3-PRRU, 2-PRU-PRRU and 2-PRS-PRRU, where P denotes a prismatic pair, R indicates a revolute pair and U is a universal joint. Analytical equations of input twist, output twist and transmission wrench are established based on inverse kinematics. Instantaneous force/motion transmission performance index is obtained over the whole space and atlases are drawn. Based on the atlases, it is shown that the three parallel mechanisms have good force/motion transformation characteristics with similar border of singularities. The 3-PRRU parallel mechanism has the biggest good-working space.