精密平动轴的热误差分析与误差建模

发布时间：2018-11-01 20:28

【摘要】：精密和超精密加工技术己经成为现代机械制造中重要的组成部分和发展方向,为了满足零件曲面的复杂性和表面精度,对精密机床的加工精度要求已越来越高。平动轴作为机床的关键部件,它的精度直接影响加工精度。由光栅尺定位、直线导轨导向、直线电机驱动提高了平动轴的精度,但内部热源与环境温度的变化会造成平动轴热变形,产生的热误差对平动轴精度造成很大影响。因此有必要对其精度进行分析,对热误差产生原因和变化规律进行研究,并建立精度较高的数学模型,为误差补偿提供准确的数据。本文以光栅尺定位、直线导轨导向、直线电机驱动的平动轴为研究对象,主要从以下几方面内容进行了研究：1)对平动轴误差元素进行分析,分析产生热误差的原因,利用齐次变换矩阵对误差的运动学关系进行解析,建立包含三项热漂移误差的误差传递矩阵,通过对热漂移误差的分离,建立了只包含热漂移误差的空间误差模型,找到热漂移误差影响平动轴精度的机理。2)利用有限元方法分别对直线导轨和光栅尺进行热特性分析,通过仿真结果分析得到两者热变形引起热漂移误差的大小及变化规律,并得到光栅尺对于温度的变化极为敏感,热变形产生的热漂移误差会极大的改变平动轴的定位误差。3)通过检测平动轴不同状态下的直线度误差与定位误差得到热漂移误差,来验证仿真结果。通过热漂误差大小的比较,得到由光栅尺热变形引起的热漂移误差是热误差的主要部分。4)结合光栅尺热膨胀对定位误差影响的机理,通过实验数据完成平动轴定位误差中几何误差与热漂误差的分离,并建立热漂移误差模型,验证得到模型精度较高,此模型可以作为误差补偿的基础。
[Abstract]:Precision and ultra-precision machining technology has become an important part and development direction in modern mechanical manufacturing. In order to meet the complexity and surface accuracy of parts surface, the precision of precision machine tools has been more and more demanding. As the key component of machine tool, the accuracy of the translational shaft directly affects the machining accuracy. The accuracy of the translational shaft is improved by the orientation of the grating ruler, the guide of the linear guideway and the driving of the linear motor. However, the change of the internal heat source and the ambient temperature will cause the thermal deformation of the translational shaft, and the thermal error will have a great influence on the accuracy of the translational shaft. Therefore, it is necessary to analyze its accuracy, to study the cause and variation of thermal error, and to establish a mathematical model with high accuracy to provide accurate data for error compensation. In this paper, the position of grating ruler, the guide of linear guideway and the translational shaft driven by linear motor are taken as the research object. The main contents are as follows: 1) the error elements of the translational shaft are analyzed, and the causes of thermal error are analyzed. The kinematics relation of the error is analyzed by using the homogeneous transformation matrix, and the error transfer matrix containing three thermal drift errors is established. By separating the thermal drift error, a spatial error model containing only the thermal drift error is established. The mechanism that the thermal drift error affects the accuracy of the translational shaft is found. 2) the thermal characteristics of the linear guideway and the grating ruler are analyzed by the finite element method, and the magnitude and variation of the thermal drift error caused by the thermal deformation are obtained by the simulation results. It is also obtained that the grating ruler is very sensitive to the change of temperature, and the thermal drift error caused by thermal deformation will greatly change the positioning error of the translational shaft. 3) the thermal drift error is obtained by detecting the straightness error and the positioning error of the translational axis in different states. To verify the simulation results. By comparing the magnitude of the thermal drift error, the thermal drift error caused by the thermal deformation of the grating ruler is the main part of the thermal error. 4) the mechanism of the influence of the thermal expansion of the grating ruler on the positioning error is obtained. The separation of the geometric error and the thermal drift error in the positioning error of the translational axis is completed by the experimental data, and the thermal drift error model is established to verify that the accuracy of the model is high. This model can be used as the basis for error compensation.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG502.3

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