To establish the dynamic model of machine tool structure is an important means to assess the performance of the machine tool structure during the cutting process. It is necessary to study the dynamics of the machine tools in different configurations for the sake of analyzing the dynamic behavior of the machine tools in the entire workspace. In this paper, a robust approach is presented to build an efficient and reliable dynamic model to evaluate the position-dependent dynamics of the twin ball screw (TBS) feed system. First, the TBS feed system is divided into several components, and a finite element (FE) model is built for each component. Second, the Craig-Bampton method is proposed to reduce the order of the substructures. Third, a multipoint constraints (MPCs) method was introduced to model the mechanical joint substructures of the TBS system, and the spring-damper element (SDE) is employed to connect the condensation nodes. Finally, a series experimental tests and full-order FE analysis are conducted on the self-designed TBS worktable in the four positions to validate the effectiveness of the proposed dynamic model. The results show that the proposed approach evaluates accurately the position-dependent behavior of the TBS system.

建立机床结构动力学模型是评价机床结构在切削过程中性能的重要手段。为了分析机床在整个工作空间中的动态行为，有必要研究不同配置下机床的动力学。在本文中，提出了一种稳健的方法来构建有效且可靠的动态模型，以评估双滚珠丝杠 (TBS) 进给系统的位置相关动态。首先，将TBS给料系统分为几个组件，并为每个组件建立一个有限元（FE）模型。其次，提出了Craig-Bampton方法来减少子结构的阶数。第三，引入了多点约束（MPCs）方法来模拟 TBS 系统的机械接头子结构，并且使用弹簧阻尼元件（SDE）连接冷凝节点。最后，在自行设计的TBS工作台的四个位置上进行了一系列的实验测试和全阶有限元分析，以验证所提出的动力学模型的有效性。结果表明，所提出的方法准确地评估了 TBS 系统的位置相关行为。