大型望远镜四通形位误差检测方法研究

发布时间：2018-07-15 12:14

【摘要】：随着国内大型光学望远镜的口径的不断增大,望远镜上的四通组件的尺寸也成倍加大。大型光学望远镜作为精密光机设备,要求具有相当高的跟踪精度,这就需要望远镜俯仰轴系在旋转过程中有较高的回转精度,在影响俯仰轴系回转精度的诸多因素中,四通组件的形位误差是一个不可忽略的误差来源。现在2m及以上口径望远镜的四通件,由于没有有效的检测手段来准确测量其的形位误差,则不能准确的指导四通两端的配合面的后续修磨,所以现在的大型四通件的精度只能依靠机床自身的加工精度来保证。这就对四通组件形位误差的检测方法的研究提出了迫切的要求,但由于四通件尺寸大、两圆柱端面跨距大、精度要求高等特点,对于4米级的大口径望远镜其四通件的两圆柱用于定位的端面距离可以达到6米左右,使其形位误差的检测难度大大提高。本论文主要研究内容包括:研究了激光跟踪仪的结构组成以及工作原理,分析了影响激光跟踪仪测距和测角精度的主要因素。根据四通结构件单站测量只能测得四通一端端面的坐标的特点,提出了转站测量的方法,并通过实验确定了激光跟踪仪的转站精度,完成了激光跟踪仪对四通的测量实验,并与三坐标测量机的测量结果进行了对比分析。根据四通形位误差的测量要求,提出并搭建了一套更方便快捷的光学测量系统,对测量系统进行了误差分析。最后通过实验验证了该测量系统对四通垂直度、平行度等形位误差测量的可行性。建立了形位误差的数学模型,用MATLAB对测量结果进行了数据处理,并采用GUM评定方法和蒙特卡洛法对测量结果的不确定度进行了评定,得到了不同类型形位误差的不确定度。本文所提出测量方法不仅可以满足2m口径望远镜四通形位误差的检测需求,对4m及更大口径的望远镜四通件的形位误差的检测与激光跟踪仪相比具有明显的优势,并且对大型轴孔类结构件的形位光差检测具有一定的借鉴意义。
[Abstract]:With the increasing aperture of large optical telescopes in China, the size of the four-way components on the telescope has multiplied. As a precision optical equipment, large optical telescopes are required to have high tracking accuracy. Therefore, it is necessary for the telescope pitching shafts to have high rotation accuracy in the course of rotation, and among the many factors that affect the rotation accuracy of pitching shafts, The configuration error of the four-way assembly is a source of error which can not be ignored. Now, because there is no effective means to measure the shape and position error of the four-way telescope with 2m or higher caliber, it is impossible to guide the subsequent grinding of the matching surface between the two ends of the four-way. Therefore, the accuracy of large-scale four-way parts can only be guaranteed by the machining accuracy of machine tool itself. This puts forward an urgent requirement for the research on the detection method of the shape and position error of the four-way component. However, due to the large size of the four-way component, the large span between the two cylindrical ends, and the high precision requirement, etc. For the large aperture telescope of 4 meters, the distance of the two cylinders of the four-way part used for positioning can reach about 6 meters, which makes it more difficult to detect the error of shape and position. The main contents of this thesis are as follows: the structure and working principle of laser tracker are studied, and the main factors influencing the ranging and angle measuring accuracy of laser tracker are analyzed. According to the characteristic that the coordinate of the end face of one end of the four-way structure can only be measured by single station measurement of four-way structure, this paper puts forward the measuring method of the transposing station, and determines the precision of the laser tracker by experiment, and completes the measurement experiment of the laser tracker to the four-way. The results are compared with those of CMM. According to the measurement requirements of the four-way position error, a more convenient and fast optical measurement system is put forward and built, and the error analysis of the measurement system is carried out. Finally, the feasibility of the system is verified by experiments. The mathematical model of the shape and position error is established, and the data of the measurement results are processed by MATLAB. The uncertainty of the measurement results is evaluated by using the GUM evaluation method and the Monte Carlo method, and the uncertainty of different types of shape and position errors is obtained. The measurement method presented in this paper can not only meet the needs of measuring the four-way position error of the 2-M telescope, but also has obvious advantages over the laser tracker in the detection of the four-way error of the 4m or larger aperture telescope. And it has certain reference significance for the shape and position light difference detection of the large axial hole type structure parts.
【学位授予单位】：中国科学院研究生院(长春光学精密机械与物理研究所)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH743

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