Abstract:

This paper addressed the static stiffness of a new heavy hybrid machine tool XNZH2430,which was developed in Tsinghua University based on a 2-DOF translational parallel mechanism.In analysis process, the structure of the machine tool can be represented by a number of nodes and elements.The holistic stiffness matrix of the machine tool was built based on the theory of element stiffness matrix.The stiffness distribution of the machine tool within a certain work space was analyzed.The analysis result indicates that the machine tool has better stiffness performance when the moving platform is close to the symmetric position.When the platform is away from the symmetric position,stiffnesses along the y and z directions are turning worse dramatically.Therefore,the moving platform should stay close to the symmetric position during working process.

Key words: hybrid machine tool, static stiffness, stiffness matrix, node

摘要：

根据单元刚度矩阵的理论，将型号为XNZH2430的新型混联机床简化为若干节点和单元组成的结构，建立了该机床的整体刚度矩阵,以此为基础，分析了该机床在一定工作空间内的静刚度分布情况。分析结果表明:当动平台处于对称位置附近的区域时，该机床静刚度相对较好；当动平台偏离对称位置时，整机y、z方向的静刚度急剧减小。因此，在实际铣削加工中应尽量让动平台处于对称位置附近区域。

关键词: 混联机床, 静刚度, 刚度矩阵, 节点