基于机床刚度特性的大型复杂曲面多轴数控加工运动规划

项目名称： 基于机床刚度特性的大型复杂曲面多轴数控加工运动规划

项目编号： No.50805057

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 闫蓉

作者单位： 华中科技大学

项目金额： 20万元

中文摘要： 多轴数控机床的动态特性存在较强的非线性和各向异性，这种特性成为影响多轴数控加工精度、表面质量和效率的主要因素，必须深入研究多轴数控动态特性与运动规划之间的内在关系，建立新的运动规划理论和方法，以满足大型复杂曲面类零件对高速多轴数控加工的迫切需求。 本项目提出了基于机床刚度特性的大型复杂曲面多轴数控加工运动规划方法，采用点传递矩阵方法快速建立机床动刚度模型，以面向加工的刚度性能指标评价任意控制点的多轴机床刚度性能，建立刚度映射图，用于多轴加工运动轨迹规划。 点传递矩阵方法采用了局部柔度矩阵集成总柔度矩阵的叠加形式形成综合柔（刚）度矩阵，较传统的动力学建模方法而言，计算效率高，与有限元法计算精度相当。面向加工的刚度性能指标可定量地评价任意加工位置的多轴机床刚度性能，刚度映射图可直观地反映局部和全部加工区域的刚度性能指标的分布规律，指导加工编程人员进行多轴加工运动轨迹规划。

中文关键词： 多轴数控机床;动刚度;运动规划;复杂曲面

英文摘要： In whole available workspace the dynamic characteristics of the multi-axis NC machine tool represents strong nonlinearity and anisotropy which has a significant effect on machining accuracy, quality and efficiency. In order to meet the urgent requirement of high-speed NC multi-axis machining for the production of large complex surface, it is essential for us to research the relationship between NC multi-axis dynamic characteristics and tool-path planning and establish a new tool-path planning method for NC multi-axis machining. In this paper a new tool-path-planning method based on machine stiffness characteristic for complex surface multi-axis NC machining is proposed. Firstly, point-transformation- matrix method is applied to establish general stiffness model for multi-axis machine tool rapidly. Then machining-oriented stiffness index is used to evaluate machine stiffness performance at any control point which is located at complex surface. At last, stiffness index map is used for multi-axis NC machining and tool-path planning. In the point-transformation-matrix method, general stiffness matrix of the multi-axis machine tool is composed of local compliance matrixes according to their contribution to the final compliance matrix, which is easier to program and more efficient than traditional dynamic modeling method. According to machining requirement, machining-oriented stiffness index is proposed to quantitatively evaluate multi-axis machine tool stiffness performance at any machining position. Thus, stiffness index map is established from stiffness indexes for us to analyze the distribution of stiffness indexes in local or whole workspace and help a part programmer to choice optimum multi-axis-machining tool-path planning.

英文关键词： Multi-axis machine tool; Dynamic Stiffness; Tool-path planning; Complex surface