基于精确计时的回转射线簇角坐标建立方法研究

发布时间：2018-08-16 19:16

【摘要】：高端装备制造领域中,对于大尺寸(尤其是内尺寸)零件的高精度、在机自动化测量方法十分匮乏。课题组此前提出了一种基于激光回转射线簇的高精度、在机自动化测量方法,经过测量实验证明可行、有效。经过进一步研究发现,利用激光回转射线簇测量法进行测量时,得到测量值对应的角坐标是提升该方法测量能力的关键。根据对现有测量系统的分析与未来的远景规划,提出了为激光回转射线簇获取角坐标方法的要求。光电编码器是常用的角坐标获取工具,它需要定子、转子间相互转动时才能实现角度坐标获取,现有测量系统难以提供这种提供定子—转子间的相对转动,而且使用光电编码器将要面对安装时的同轴度误差带来的角度误差,因此光电编码器不适合为激光回转射线簇建立角度坐标。其他传统现有角度测量方法也往往因为测量系统复杂等原因不适于为激光回转射线簇建立角度坐标。利用精确计时获取角度坐标的方法有WMPS与时栅法。WMPS是一种需要合作目标的发射——接收互动系统,而时栅法系统结构复杂,仍需要实体器件,因此这两种方法也不适于为激光回转射线簇建立角度坐标本文提出了一种基于精确计时的激光回转射线簇角坐标建立方法。在无实体分度元件、无合作目标情况下,将角位移测量转换为时间测量,由测量信息自整定,通过精密时间间隔测量为每个位移测量值赋予了高精度的角度坐标。依此方法研发了具有自备电源、无线数据传输能力的可安装于机床主轴的测量头。为验证方法的有效性,设计了两个器件作为测量对象:一个为包含两个二面角的工件,另一个为正二十八边形孔。借助立式铣床主轴完成了对二面角对正二十八边形内孔的测量。分析实验结果知道测时模块的准确性与主轴回转的匀速性满足要求,另将二面角测量值与用海克斯康三坐标测量机测得的标准数据对比,二面角角度测量误差在10?左右,相对测量误差为0.028%。将正二十八边形孔的测量值与用影像测量仪对正二十八边形孔测得的标准数据对比,各边长拟合的最大测量误差低于50μm,相邻边夹角的最大测量误差低于3?。实验结果证明了本方法的可行性。
[Abstract]:In the field of high-end equipment manufacturing, there is a lack of automatic measurement methods for large-size parts, especially for internal-size parts. A high precision and automatic measurement method based on laser rotating ray cluster has been put forward by our research group, which has been proved to be feasible and effective by measurement experiments. After further study, it is found that the key to improve the measuring ability of the method is to obtain the angular coordinates corresponding to the measured values when using the laser rotating ray cluster measurement method. Based on the analysis of the existing measurement systems and the future prospect planning, the requirements of the method for obtaining angular coordinates for laser rotating ray clusters are proposed. Photoelectric encoder is a commonly used tool for obtaining angular coordinates. It requires the rotation of stator and rotor to achieve angle coordinate acquisition. It is difficult to provide this kind of relative rotation between stator and rotor by existing measuring system. Moreover, the photoelectric encoder will face the angle error caused by the coaxiality error of the installation, so the photoelectric encoder is not suitable to establish the angle coordinate for the laser rotating ray cluster. Other traditional angle measurement methods are often not suitable for the laser rotation ray cluster because of the complexity of measurement system and other reasons. The accurate timing method for angle coordinates is WMPS and time grating method. WMPS is an interactive transmitting and receiving system which needs cooperation target, but the system structure of time grid method is complex, and it still needs solid devices. Therefore, these two methods are not suitable for the establishment of angular coordinates for laser rotating ray clusters. In this paper, a new method based on precise timing for the establishment of angular coordinates of laser rotating ray clusters is proposed. In the case of no solid indexing element and no cooperative object, the angular displacement measurement is transformed into time measurement, and the measurement information is self-adjusted, and each displacement measurement value is given high precision angular coordinates by precise time interval measurement. According to this method, a measuring head with self-provided power supply and wireless data transmission capability can be installed on the spindle of machine tool. To verify the effectiveness of the method, two devices are designed as measuring objects: one is a workpiece with two dihedral angles, the other is a regular 28 side hole. The dihedral angle is measured with the help of the spindle of vertical milling machine. The experimental results show that the accuracy of the time measurement module and the uniformity of the spindle rotation meet the requirements. In addition, the dihedral angle measurement value is compared with the standard data obtained by the Hexkon CMM. The error of the dihedral angle measurement is 10? The relative measurement error is 0. 028. By comparing the measured value of the normal 28 side hole with the standard data of the 28 side hole measured by the image measuring instrument, the maximum measuring error of each side length fitting is less than 50 渭 m, and the maximum measuring error of the adjacent edge angle is less than 3 渭 m. The experimental results show the feasibility of this method.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH741

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