基于边界元法的混联数控机床整机结构动态特性解析

基于边界元法研究混联数控机床整机结构动态特性的解析和建模方法。首先采用粱单元、集中质量单元、弹簧单元及结合部单元建立混联机床整机结构动力学模型，基于边界元方法建立各单元的动力学方程式，通过单元合成方法推导出混联数控机床整机结构动力学方程，用频率扫描法得到整机结构的固有频率。基于所建立混联机床结构动态特性解析方法，开发相应的整机动态特性解析软件，实验证明，所建立混联机床整机动态特性解析方法及开发的软件是可靠的，不仅可以为混联数控机床加工过程中回避薄弱位姿状态提供依据，而且可以为混联数控机床的结构设计提供理论依据，对提高混联数控机床的设计水平具有重要意义。

DYNAMIC ANALYSIS OF A SERIES-PARALLEL NC MACHINE TOOL STRUCTURE BASED ON THE BOUNDARY ELEMENT METHOD

The dynamic modeling and analysis of a series-parallel type numerical control (NC) machine tool structure is established based on the boundary element method (BEM). First the elements such as beams, lumped-masses, springs and joints are used to set up the dynamic model of the whole structure of series-parallel NC machine tool. Then the dynamic equations of elements are established by the BEM. And the dynamic equation of the whole structure of series-parallel NC machine tool is constructed by synthesis of the elements. From the dynamic equation of the who1e machine structure, the natural frequencies of the whole machine structure can be obtained by the frequency scanning method. The software for analysis the dynamic behaviors of the whole machine structure is developed based on the proposed dynamic analysis method. Finally the dynamic experiment for a new series-parallel type NC machine tool 6PM2 showed that the proposed dynamic analysis method and the developed software could be used to analyze the dynamic behaviours of the whole structure of a series-parallel NC machine tool, and can provide the theoretical bases for avoiding the weak pose of the parallel mechanism during machining processes and for the design of a series-parallel NC machine tool. It can improve the design level of a series-parallel type numerical control machine tool structure.