中文摘要：

新型四自由度2PUS－2PRS并联机构适用于搭建大型结构件的高速铣削装备。工作空间分析是其参数设计的基础。在分析该机构拓扑特性的基础上，首先运用矢量法构建了其位置逆解的解析表达式；并采用几何包络面理论，导出该并联机构工作空间受限的约束集合；进而通过数值求解，得到其定姿态工作空间截面面积与姿态角的变化规律。

英文摘要：

The novel 4 -DOF parallel mecha-nism of 2PRS - 2PUS can be applied to build up high-speed milling equipment for large structure component. The workspace analysis is the basic task for parameters design. First of all, based on the topology analysis, the inverse kinematics of this mechanism is set up. In addition, the border＇ of workspace is derived by using the theory geometric enveloping. Furthermore, the variations between the area of the fixed - orientation workspace and the orientational are solved by using the numerical method and provide the guidance for further research of the design of parallel mechanism.