四自由度同步外差干涉测量系统设计

A heterodyne interferometry for simultaneous measurement of four degrees of freedom

针对多自由度测量技术中存在的测量范围有限、精度低和阿贝误差等问题,设计了一种大行程、高精度、可溯源、四自由度同时测量的外差干涉测量系统。采用碘稳频532 nm固体激光器作为测量仪光源,结合光纤耦合技术对双频光进行空间分离。使用差分波前传感技术实现位移、俯仰角和偏转角的同步检测,并采用楔面棱镜测量直线度的变化。该测量系统可以抑制双频光混叠引起的非线性误差,行程范围为6 m,位移分辨率为0.13 nm,俯仰角和偏转角分辨率为0.026μrad,直线度分辨率为14.88 nm,测量结果具有可溯源性。

Aiming at the problems of limited measurement range,low accuracy and Abbe error in multi-degree-of-freedom measurement technology,a large-travel,high-precision,traceable,fourdegree-of-freedom simultaneous measurement of heterodyne interferometry was proposed.The miniaturized 532 nm solid-state laser with iodine frequency stability was used,and the optical fiber coupling technology was used to spatially separate the dual-frequency light.Differential wavefront sensing technology realized the simultaneous detection of displacement,pitch and yaw,and wedge prisms are used to measure the change in straightness.The measuring instrument can suppress the non-linear error caused by dual-frequency optical aliasing,and realize the measurement with a travel range of 6 m,a displacement resolution of 0.13 nm,a pitch and yaw angle resolution of 0.026μrad,and a straightness resolution of 14.88 nm.The measurement results are traceable.