Research of a fast and accurate measuring method for guide planes of ultra precision machine

为了准确地测量平整度，有必要建立一个平面标准。在本研究中，用汞表面所代表的重力方向作为平整度的标准。本研究提出了一种数据处理方法，称为2点法，可以提高空间波长的分辨能力。研究结果表明：在所研制的光学液位计中，利用LED和光电二极管阵列构成的光学系统来感知液位计的两个方向倾斜。研制的液位计动态范围为30分钟。（弧）和2秒（弧）的分辨能力。其尺寸为30x30x50 （mm）立方长，300克重。如果水平仪的两个支撑腿之间的间距为20mm，则高度分辨率的精度达到0.4微米。采用二点法，采样间隔不受腿的跨度的限制，这是直线度测量中常用的连续链式法的一个难点。在两点法中，采样间隔可以根据必要的空间波长和采样定理的要求来确定。用二维水准仪测量水平面的平整度比用光电自准直仪测量水平面平整度方便、快捷。在测量中，水准仪的三个支腿的三角形被一步一步地放置在被测量平面上网格化的连续三角形上。

In order to measure flathess accurately, it is necessary to establish a standard of flat plane. In this research, gravitational direction which is represented by a mercurial surface is used as a standard of flatness. Resolutional ability in spacial wave length can be improved by a data processing method which has been developed in the research, and named 2-points method. Results obtained by the research are as follows:In the developed optical level meter, the two directional inclination of the level is sensed by an optical system constructed by a LED and a photodiode array. The developed level meter has the dynamic range of 30 min.(arc) and resolutional ability of 2 sec.(arc). And its dimensions are 30x30x50 (mm) in cubic lengthes and 300 g in weight. If a span of 20 mm is given between two supporting legs of the level, the accuracy of resolution in heihgt attains 0.4 micro meter. Using the 2-points method, sampling intervals is not restricted by the span of legs, which has been a difficult point of the succesive chained method usually used in the measurement of the straightness.In the 2-points method the sampling intervals can be determined in correspondent with necessary spacial wave length and requirement of the sampring theorem.Using the two dimensional level meter, the flatness of a horizontal plane can be measured more easily and speedily than by the optoelectoronic autocollimater. In the measurement the triangle of the three supporting legs of the level, is placed step by step on successive triangles which are meshed on the plane to be measured.