多轴数控机床刀具端动态特性测试评估及其软件开发

发布时间：2018-01-01 03:04

本文关键词：多轴数控机床刀具端动态特性测试评估及其软件开发　出处：《华中科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：机床的动态特性影响其加工稳定性,从而影响加工效率、工件质量、刀具寿命等关键指标,通过稳定性叶瓣图来获知机床的加工稳定性,其必要前提是得到机床刀具端的频响函数。为避免重复实验,采用三分量响应耦合子结构分析法,建立机床刀具端频响函数的预测模型,将机床系统划分为主轴-刀柄上段子结构、刀柄下段子结构和刀具子结构,通过耦合各子结构频响函数获得整体频响函数。采用复刚度矩阵方法辨识柔性结合部,用一个2×2的对称复刚度矩阵代表柔性结合部,通过逆响应耦合法求解矩阵中三个未知矩阵元素,可预测不同刀具刀柄组合的刀尖点频响函数。对比复刚度矩阵计算方法和遗传算法辨识刀柄刀具之间柔性结合部频响特性的效率和精度,结果显示复刚度矩阵计算方法模型更精确,计算效率更高,而对实验误差较敏感。选取静刚度、固有频率、最小动刚度、界宽、过柔度等5个动态特性评价参数,给出通过频响函数来计算这些评价参数的计算过程。基于以上理论,整合MATLAB的计算工作和ANSYS的仿真工作,开发相应的机床动态特性预测与评估软件。按照树状节点管理结构搭建了软件的整体框架,将RCSA方法和评价参数提取方法的应用简化为软件中的指定输入和输出的操作,输入所需的实验数据和刀柄模型,输出预测的频响函数等。该软件可用于预测和评估不同工作位姿下不同刀柄、刀具组合的机床刀具端动态特性。基于以上的理论方法,在多轴数控机床动态特性预测与评估软件平台上,分别对重型五轴联动机床和车铣复合加工中心在不同工作位姿情况下的动态特性进行测试、预测和评估,给出了机床动态特性的定量评估,并在此基础上对机床进行加工稳定性分析。
[Abstract]:The dynamic characteristics of the machine tool affect the machining stability, thus affecting the machining efficiency, workpiece quality, tool life and other key indicators. The stability of the machine tool can be obtained by the stable blade diagram. The necessary premise is to obtain the frequency response function of the tool end of the machine tool. In order to avoid repeated experiments, the prediction model of the frequency response function of the tool end of the machine tool is established by using the three-component response coupling substructure analysis method. The machine tool system is divided into the spindle and the upper segment structure of the tool handle, the substructure of the lower section of the tool handle and the tool substructure. The global frequency response function is obtained by coupling the frequency response function of each substructure. The flexible joint is identified by the complex stiffness matrix method, and a 2 脳 2 symmetric complex stiffness matrix is used to represent the flexible joint. The inverse response coupling method is used to solve the three unknown matrix elements in the matrix. The frequency response function of different tool shanks can be predicted, and the efficiency and precision of identifying the frequency response characteristics of flexible joint between tools with different tool-shanks can be compared with the calculation method of complex stiffness matrix and genetic algorithm. The results show that the calculation method of complex stiffness matrix is more accurate, more efficient and more sensitive to experimental errors. The static stiffness, natural frequency, minimum dynamic stiffness and boundary width are selected. The calculation process of these parameters is given by frequency response function. Based on the above theory, the calculation work of MATLAB and the simulation work of ANSYS are integrated. The software for predicting and evaluating the dynamic characteristics of machine tools is developed, and the whole framework of the software is built according to the tree node management structure. The application of RCSA method and evaluation parameter extraction method is simplified as the operation of specified input and output in software, the input of required experimental data and cutter handle model. The software can be used to predict and evaluate the dynamic characteristics of tool ends with different tool-shanks and tool combinations under different working position and posture. Based on the above theory and method, the software can be used to predict the frequency response function of the output prediction. The dynamic characteristics of heavy five-axis machine tool and turn-milling composite machining center were tested, predicted and evaluated on the platform of multi-axis NC machine tool dynamic prediction and evaluation software. The quantitative evaluation of the dynamic characteristics of the machine tool is given, and on the basis of this, the machining stability of the machine tool is analyzed.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG659

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