A Wollaston Prism and Corner Cube Reflector Cooperative Sensing Heterodyne Interferometer for Simultaneous Measurement of Straightness Errors and Displacement

Abstract

In this study, a novel Wollaston prism (WP) and retroreflector (RR) cooperative sensing heterodyne interferometer (CSHI) for simultaneous measurement of straightness errors and displacement is proposed. In this CSHI, a WP, a corner cube reflector (CCR), and a beam splitter are assembled together to act as the sensor for straightness errors and displacement measurements. Thanks to this ingenious design, the return direction of the straightness and displacement measurement beams does not change with the rotation of the measured object, thereby increasing the linear measurement range from a few hundred millimeters to several meters. Therefore, the proposed CSHI can not only achieve the simultaneous measurement of the straightness errors and displacement but also make the straightness error measurement unaffected by the rotation error of the measured object. In addition, the influence of horizontal straightness error on displacement measurement is analyzed and validated. The optical configuration of the proposed CSHI is described in detail. An experimental setup was constructed and a series of experiments were carried out to verify the feasibility and effectiveness of the CSHI. The experimental results showed that within a range of 4 m, the standard deviations (SDs) of the vertical straightness error and displacement measurement results between the proposed CSHI and a commercial interferometer achieved 0.12 and $0.11~\mu $ m/m, respectively. Thus, the proposed CSHI has a great potential in industrial applications such as the ultraprecision machine-tool control, precision motion stage testing, and displacement sensor calibration.