Double-diffractive-grating heterodyning interference roll angle measuring device and method

Abstract

The invention discloses a double-diffractive-grating heterodyning interference roll angle measuring device and method. The measuring device comprises a laser source, a double-diffractive-grating unit, an interference unit and a retroreflection unit, and the interference unit divides a laser beam into first polarized light and second polarized light; the first polarized light enters a first grating along a first optical path, enters the retroreflection unit along a second optical path through diffraction of the first grating, and is reflected through the retroreflection unit to reflect back the first polarized light to the interference unit along a third optical path and a fourth optical path parallel to the first optical path and the second optical path to serve as a first measuring light beam; the second polarized light enters a second grating along a fifth optical path parallel to the first optical path, enters the retroreflection unit along a sixth optical path through diffraction of the second grating, is reflected through the retroreflection unit, and is reflected back to the interference unit along a seventh optical path and an eighth optical path parallel to the fifth optical path and the sixth optical path to serve as a second measuring light beam, and therefore a roll angle is measured.

Description

technical field [0001] The invention belongs to the technical field of laser precision measurement, and relates to a grating interferometer device and method for measuring the roll angle (deviation) of a linear motion or displacement direction. Background technique [0002] The precision guide rail kinematic pair is the key common moving part of modern precision engineering, and is widely used in high-tech fields such as CNC machine tools, aerospace military industry, and synchrotron radiation. All guide rail kinematic pairs have three degrees of freedom of rotation angle errors, namely pitch angle, yaw angle and roll angle. Roll angle measurement is the premise and basis for error compensation and accuracy improvement, and it is also one of the key technologies for precision reference measurement and geometric measurement. Compared with the former two, the existing roll angle measurement methods or instruments are difficult to meet the high-precision measurement requiremen...

AI Technical Summary

Problems solved by technology

The Chinese patent publication number of Yin Chunyong et al. is CN1335483A "Roll Angle Measuring Method and Roll Angle Measuring Apparatus" discloses based on the transverse Zeeman laser, makes the orthogonally polarized light slightly ellipsoidized with 1 / 4 wave plate, and then uses 1 The / 2 wave is used as the sensing element to detect the phase change caused by the 1 / 2 wave plate in the nonlinear sensitive area, and the roll angle value is obtained by measuring the phase difference between the phase meter and the reference signal. Although this method has high sensitivity, it is not The linear region needs to be calibrated, which affects the measurement accuracy; and the Chinese patent publication number of Wang Zhao et al. is CN102654392A "a roll angle measurement device and method based on array multiple reflections" and the publication number is CN102818541A ​​"a high-resolution roll angle Rotary Angle Measuring Device and Measuring Method" proposes a phase method based on multiple reflections to achieve the purpose of improving resolution, and discloses the measurement optical paths and principles of two types of multiple reflectors based on arrays and lenses.

This method can achieve high resolution, but the nonlinear response curve needs to be calibrated, which reduces its accuracy and lacks stability

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