【作者】 陈诚；

【导师】 裘祖荣； 李醒飞；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2010， 博士

【摘要】 坐标测量机作为一种高效率的精密测量系统,是现代工业检测、质量控制和制造技术中不可缺少的重要测量设备。其技术水平是现代测量技术和制造技术水平高低的一个重要标志。随着坐标测量机精度和速度要求的不断提高,基于准刚体结构模型和低速状态下的坐标测量机误差模型,不能很好地描述测量机的各种非准刚体特性以及动态特性引起的附加误差。另外,较高的运行速度,使得基于滚珠丝杠和滚动直线导轨副结构的驱动系统产生较大的温升,引起不能忽略的热误差。本文基于某θFXZ型坐标测量系统,对该测量机非准刚体结构变形、动态特性和热特性以及该测量机驱动系统热误差模型等方面进行了深入的分析和研究。主要研究工作包括:1.本文针对特定结构形式的测量系统,基于测量机准刚体模型,引入附加变形误差项,建立该结构测量机非准刚体数学模型,确定了非准刚体误差的表达形式,并提出了特定结构形式测量系统的非准刚体结构误差分析方法。利用该方法,设计实验,通过激光干涉仪系统对该误差进行检定,并将检定结果做误差补偿,有效地提高了测量机精度。2.针对滚珠丝杠传动的驱动系统,建立柱坐标系下丝杠导热微分方程,根据边值条件对该方程求解。分析丝杠对不同热源作用下,温度响应的可叠加性。并通过对单热源条件下丝杠温度场分析,结合理论模型与丝杠实际温升情况,提出分段建模的思想,建立丝杠温度场分段模型。该模型在不同单热源及双热源实验条件下,都能得到较好的丝杠温度场预测。3.根据测量机不同运行条件及其驱动系统温升引起的空间定位误差,深入分析测量机的动态及温度特性。分析不同运行条件和驱动系统温度变化对测量机定位精度的影响关系,为空间定位误差补偿技术的研究提供了重要依据。4.通过分析在不同运行条件下所得测量机关键点温度值和驱动系统热误差,发现不同运行条件下实验可导致相近的热误差,但测量机关键点温度具有较大的差异。基于此现象,提出在热误差建模过程中,综合考虑测量机关键部件温度和运行条件因素的影响,采用人工神经网络建模,并与只考虑温度的建模结果进行比较。实验结果表明,依据该建模思想所建立的热误差模型具有更好的预测精度。更多还原

【Abstract】 Coordinate measuring machines (CMMs) are dispensable and important measuring equipments in modern industrial inspection, quality control and manufacture. which are high efficiency precision measuring systems. The technology of CMMs represents the level of both modern measuring and manufacture technology. CMMs are expected to complete measuring assignment more precisely and quickly. Because of the improvement of CMMs’precision and speed, the CMMs error model, which is based on the rigid body model and low-speed operation state, can’t commendably describe the additional error induced by the CMMs’non-rigid body and dynamic characteristic. The high operating speed results in a large temperature rise of drive system which consists of ball-screw and linear rolling guide, and brings on thermal error which can’t be ignored.This paper presents the analysis and study of non-rigid body structure deformation, dynamic and thermal characteristic, and drive system thermal error modeling based on the CMMs withθFXZ structure. The main research works include:1. Basing on the non-rigid body model of CMMs, an additional deformation error item was introduced for measuring system with special structure. Non-rigid body model, the error expression form and the error analysis method of the specific CMMs were defined. According to the study above, experiment was designed to calibrate the error by laser interferometer. Finally, the error compensation was carried out to improve the CMMs’precision.2. In term of the ball screw drive system, the heat transfer differential equation of screw was established and solved according to boundary value in cylinder coordinate. The temperature response superposition was analyzed in different heat sources. Analyzing the screw temperature distribution of single heat source, theory model and actual temperature rise of screw was combined. The subsection modeling idea was proposed and a screw temperature field subsection model was built. The model got an expected result in screw temperature field prediction of single heat source and double heat sources.3. The CMMs’dynamic characteristic and temperature characteristic were deeply analyzed according to location error induced by different operating conditions and temperature rise of drive system. The influence on CMMs’location error of different operating conditions and drive system temperature variation were analyzed to provide important references for research of spatial location error compensation.4. The key parts temperature and drive system thermal error were analyzed in different operating conditions. It was found that the thermal error values are close while the temperature values of CMMs’key parts in different experiments make a large difference. In term of the phenomenon, the key parts temperature and operating condition are both considered during the thermal error modeling process. The model was built by artificial neural network and compared with the model built only considering the temperature. The result showed that the thermal error model built based on the modeling idea achieved a higher predicting precision.更多还原