目的 为了提高工作效率，减少劳动力，提出一种3-URPR并联机构，用于包装生产线上对灌装瓶子的压盖工序。方法 首先利用SolidWorks画出3-URPR并联机构的三维模型，然后对该并联机构建立坐标系，基于螺旋理论求解该并联机构的自由度，最后采用空间封闭矢量法求解3-URPR并联机构的位置逆解，利用Matlab编程求解出3-URPR机构的可达工作空间，并且对该机构在灌装机上对已经灌装好的瓶子进行压盖工序了实例分析。结果 求解得到3-URPR并联机构具有3个自由度(沿x轴和y轴的转动，沿z轴的移动)，且该机构的工作空间内部是连续的，没有出现空洞的情况，给出了瓶子压盖工序的实例。结论 该机构工作性能良好，可以应用于生产线上对已灌装完毕的瓶子进行压盖工序，既可以实现对没有倾角的瓶口进行压盖，也可以实现对有倾角的瓶口进行压盖。

The work aims to propose a 3-URPR parallel mechanism for the capping process of filling bottles on the production line improve work efficiency and reduce labor force. SolidWorks was firstly used to draw a three-dimensional model of 3-URPR parallel mechanism, and then a coordinate system was established for the parallel mechanism. Based on the screw theory, the freedom degree of the parallel mechanism was solved. And finally, the closed space vector method was used to solve the position inverse solution of 3-URPR parallel mechanism. The Matlab programming was used to solve the reachable workspace of 3-URPR mechanism. Example analysis was conducted on the capping process of this mechanism on the filling machine. The solution showed that the 3-URPR parallel mechanism had 3 degrees of freedom (rotation along the x-axis and y-axis, and movement along the z-axis). The interior working space of the mechanism was continuous and free from cavity. An example of capping on the bottle was given. The mechanism has good performance. It can be used in the production line for the bottle-capping process after filling. It can be used for the bottle-capping process with and without inclination.