一种滚转角和直线度同步干涉测量方法的研究

提出一种用于精密线性位移台滚转角和运动直线度同步测量的激光外差干涉系统。该干涉系统由一个Koster棱镜、角隅棱镜、分光镜、1/2波片、直角棱镜、1/4波片以及楔面棱镜和楔面反射镜组成。楔面棱镜作为测量运动直线度和滚转角的传感器固定在线性导轨上,当双频激光器的光射入干涉系统中后,形成空间对称的六光束测量信号。空间结构对称、系统共光路的特点使光学分辨率比普通的迈克尔逊干涉仪高一倍,光程死区达到最小。系统稳定性好,抗环境干扰能力强。光路对称使得增加或减小的光程变化相同,其他自由度引起的光程变化相互抵消,仅有运动直线度和滚转角的变化可以进入光程差,有效地排除其他自由度及阿贝误差的串扰,实现高精密测量。试验证明相互平行且不同频率的两束光在同一反射系统中发生运动直线度偏移和滚转角变化时,通过两束光携带的不同相位信息能直接得到运动直线度和滚转角的变化值。它不需要一条与行程同样长度的大反射镜作参考便能够实现高分辨率测量,简单实用,可直接溯源米定义。

A Research of Roll and Motion Straightness Synchronous Measurement Based on an Interferometer

A laser heterodyne interference system for the simultaneous measurement of the roll angle and motion straightness of a precision linear stage is presented. The interference system consists of a Koster prism, a corner cube, a beam splitter, a 1/2 wave plate, a right angle prism, a quarter wave plate, a wedge prism and a wedge mirror. The wedge prism is fixed on the linear guide as a sensor for measuring the straightness and the roll angle. When the light of the dual-frequency laser is injected into the interference system, a spatially symmetric six-beam measurement signal is formed. The spatial structure is symmetrical, and the system's common optical path makes the optical resolution twice as high as that of the ordinary Michelson interferometer, the optical path dead zone can be minimized. The system has good stability and strong resistance to environmental interference. The optical path symmetry makes the optical path variation of the increasing or decreasing the same. Only the change of the straightness and the roll angle can enter the optical path difference, effectively eliminating the crosstalk of other degrees of freedom and the crosstalk of the Bayer error enables high precision measurements. Experiments show that two beams of light parallel to each other and different frequencies are in the same reflection system. When the straightness shift and the roll angle change, the difference between the straightness and the roll angle can be directly obtained by the different phase information carried by the two beams. It does not require a large mirror of the same length as the reference for high resolution, it is simple, practical and can be directly traced to the meter definition.