【作者】 李锋；

【导师】 杨建国；

【作者基本信息】 上海交通大学 ， 机械制造及其自动化， 2011， 硕士

【摘要】 提高数控机床加工精度对于现代制造业有着十分重要的意义。本文针对某能源设备工厂主要精加工设备7.5m数控双柱立式车床实际存在的两个影响加工精度的误差来源:滑枕偏摆和工作台抬升,致力于以系统、科学的理论和方法为基础,提出相应的应对方案并加以实践。误差补偿是提高机床加工精度的有效方法。文章首先介绍了误差补偿技术的主要环节,并回顾了误差建模与检测的研究现状,最终确定了机床误差运动学综合建模、误差测量、热误差建模及分析的研究步骤和内容。机床误差运动综合模型对于机床精度分析及误差补偿都非常必要。本文采用多体系统运动学描述了机床主要机构,建立了包含运动误差和热误差的误差运动综合模型,并且结合机床实际情况分析了各类误差元素对加工误差的作用方式和影响程度,阐明对关键角度误差元素建立在线监测系统的必要性。为了实时监测滑枕和工作台的工作状态,提高设备精度检测及维护效率,通过虚拟仪器技术建立了基于涡电流位移传感器和数据采集卡的测量系统。其间,详述了系统开发过程中的方案考虑、硬件组成、抗干扰措施和软件功能等内容,并介绍了在现场试验的情况,验证了该系统的精确性和稳定性。对于工作台而言,同时建立了温度采集系统,来获取与工作台上升位移同步的温度信息,以进行热误差建模和故障诊断分析。最后讨论了回归分析理论在工作台上升分析中的应用。本文叙述了普通最小二乘建模方法、逐步回归分析与岭回归分析,并讨论了变量选择及共线性分析。在此基础上,利用上升位移与温度数据,建立相应的“最优”线性回归模型,并给出各变量之间的相关性及显著性分析,为误差预报和故障诊断提供有效信息。更多还原

【Abstract】 The improvement of machining accuracy of CNC machine tools has a very important significance for the modern manufacturing industry. In this paper, the study focuses on a 7.5m CNC double column vertical lathe. As the mainly finishing equipment in an energy equipment factory, this machine tool exists two error sources: ram deflection and the table lift, which greatly impact the machining accuracy. Based on the systematic and scientific theories, the corresponding solutions and methods are proposed, as well as practiced in field.Error compensation is the effective method to improve machine tool accuracy. The thesis firstly introduces the main parts of error compensation, and makes a review of the status in error modeling and measuring. Finally, the main research procedures and contents are determined as: machine tool error synthesis modeling, error measurement, thermal error modeling and analysis.The error synthesis model is quite necessary to analyze machine tool accuracy and execute error compensation. The paper describes the main kinematical structure of machine tool by multi-body system kinematics theory, and establishes error synthesis model contained the geometric and thermal errors. Considering the actual constructions of machine tool, the different influences to final machining accuracy of all sorts of errors are discussed, and clarify the importance to establish on-line measurement system for the significant angle errors.In order to monitor the status of ram and chuck table, as well as to improve the efficiency of machine tool accuracy measurement and maintenance, an on-line measurement system consisted of eddy current displacement sensor and data acquisition card is established in virtual instrument technology. In section 3, the details of the system development process are discussed: the solution schemes comparison and selection, the hardware construction, the measures to anti-interference and the features of software. In addition, a temperature data acquisition system is established for the chuck table, so the rise displacement and components temperature can be obtained synchronously.At last, the regression analysis is applied in thermal error modeling and the chuck-table fault diagnosis. The paper describes the multivariate regression modeling, stepwise regression analysis, ridge regression analysis, as well as discusses the variable selection and collinearity analysis. On this basis, the“optimal”linear regression model is fitted by the chuck-table rise displacement and temperature data. Then, the relationship between variables and their significance analysis are provided.更多还原