基于螺旋理论求解移动并联机构在单个分支驱动下的分支传递力螺旋和机构输出运动螺旋，给出机构分支在不同位姿下传递功率恒定及其实现最大功率传递的条件。通过分析移动并联3-CPU机构的运动/力传递性能，给出分支将输入功率全部转化为动平台输出功率，即运动/力传递性最大时的主动副配置方式。在此基础上，对移动并联3-PRPU机构进行运动/力传递性能分析，总结其结构参数对分支传递功率的影响规律，得到了其传递性最大时的参数设置。所做工作为分析与综合具有高传递能力的并联机构提供了理论参考。

：A method solving the output twist screw and the transmission wrench under the motion of a single limb is proposed based on the screw theory. Some conditions that a mechanism requires to realize the constant power transmission and reach the best motion/force transmissibility in different poses are presented. By taking the 3-CPU translational parallel mechanism as an example,the motion/force transmissibility performance of the mechanism is analyzed. In the meanwhile,the allocation pattern of the actuated joint when a limb can transmit all its input power to the moving platform is presented. The motion/force transmissibility performance of the 3-PRPU translational parallel mechanism is analyzed,and some effects of configurations to the transmission power of a single limb are summarized. The work can make a contribution to analyzing and synthesizing parallel mechanism with good motion/force transmissibility.