Search

CN-120521536-B - Angle measurement method and device based on micro-wavelength difference dual-wavelength interference

CN120521536BCN 120521536 BCN120521536 BCN 120521536BCN-120521536-B

Abstract

The invention relates to the technical field of optical precision measurement and discloses an angle measurement method and device based on micro-wavelength difference dual-wavelength interference, comprising the following steps of adopting a dual-wavelength expansion light source with micro-wavelength difference to generate equal-inclination interference fringes through a Michelson interferometer; the tilt angle is measured indirectly by the fringe variation characteristic of the dual-wavelength interference of the small wavelength difference. The interference method and the device for measuring the angle are simple and easy to operate, convenient to install and debug, suitable for high-precision measurement of small angles and angles around 180 degrees, sensitive in response, good in accuracy and suitable for computer automatic analysis and processing by using the blurring or the definition of interference fringes as judgment and positioning basis, and can obtain the order-of-magnitude precision of seconds by using a low-precision linear displacement mechanism to obtain the measurement of the high-precision angles.

Inventors

  • LIU JINGYOU

Assignees

  • 淮阴师范学院

Dates

Publication Date
20260508
Application Date
20250610

Claims (9)

  1. 1. The angle measurement method based on the micro-wavelength difference dual-wavelength interference is characterized by comprising the following steps of: S1, generating equal-inclination interference fringes by a Michelson interferometer by adopting a dual-wavelength extended light source with a small wavelength difference; S2, using a linear moving mechanism capable of adjusting the inclination direction to enable the plane reflecting mirror of the test light beam to move along the inclination direction; S3, indirectly measuring the inclination angle by measuring the moving distance of the plane reflecting mirror when the interference fringes are the most blurred in two successive times in the moving process of the plane reflecting mirror along the inclination direction; S4, selecting different angle calculation formulas according to the inclination angle measured twice and the measurement situation of the inclination angle measured twice, and calculating the measured angle.
  2. 2. The angle measurement method based on the micro-wavelength difference dual-wavelength interference of claim 1, wherein the light emitted by the micro-wavelength difference dual-wavelength light source becomes an extended light source after passing through a frosted glass screen, two coherent light beams are separated by a cube beam splitting prism, the upward reflected light beam is a reference light beam, and the light beam which directly passes through the cube beam splitting prism is a test light beam; The reference beam is reflected by the reference beam reflector and returns along the original path, and then reaches the CCD camera through the cubic beam splitting prism; The test beam is reflected by the test beam reflector and returns along the original path, and then is reflected by the cube beam splitting prism and reaches the CCD camera; The CCD camera focuses to observe the isocratic interference fringes of the extended light source towards infinity, or the naked eyes directly focus to observe the isocratic interference fringes towards infinity.
  3. 3. The method for measuring an angle based on the micro-wavelength difference dual-wavelength interference according to claim 2, wherein the test beam reflecting mirror is moved in an oblique direction of the principal ray by adjusting the test beam reflecting mirror, and a reflecting surface of the test beam reflecting mirror is perpendicular to the principal ray; The inclined moving direction of the test beam reflector and the included angle of the mirror surface are set as Assuming that the displacement of the test beam reflector along the oblique direction is c, the distance of the reflecting surface moving along the direction of the principal ray is b, and the calculation formula is as follows: (3) In the formula, the displacement c in the oblique direction is a displacement amount measured directly, and the displacement b of the mirror surface of the test beam reflector along the direction of the principal ray is a displacement amount measured indirectly.
  4. 4. The method for measuring an angle based on dual wavelength interference of small wavelength difference as set forth in claim 3, wherein the method for measuring an angle based on dual wavelength interference of small wavelength difference is characterized in that when the method is used for indirect measurement by tilting a test beam reflector Is the distance that the test beam mirror moves when the two successive fringes measured in the tilt direction are most blurred, Is the inclination angle of the moving direction, and the two wavelengths of the dual-wavelength light source with small wavelength difference are respectively And The wavelength difference is Considering the small wavelength difference between the two wavelengths, the square of the average wavelength can be approximated Then there is the formula: (4) selecting a suitable dual wavelength of known small wavelength difference And By measuring the inclination angle of the test beam reflector when the continuous two interference fringes are most blurred Distance of movement in the oblique direction of (a) Indirectly measure the inclination angle For this purpose, the formula (4) is converted into: (5) The inclination angle is obtained from the formula (5): (6) the inclination angle measurement error caused by single measurement is obtained by mathematical differential operation in the formula (6): (7)。
  5. 5. the angle measurement method based on micro-wavelength difference dual wavelength interference of claim 4, wherein the inclination angle measurement error caused by single measurement can be obtained by mathematical differentiation operation according to the formula (5): (8) As can be seen from equation (8), the smaller the tilt angle position value, i.e., the closer to the 0 DEG start angle position, the distance moved when the two successive fringes are most blurred The larger the resulting angular position measurement error is, the smaller.
  6. 6. An apparatus for implementing the minute wavelength difference dual wavelength interference-based angle measurement method according to any one of claims 1 to 5, comprising: A dual wavelength extended light source of a small wavelength difference; the Michelson interferometer comprises a ground glass screen, a cube beam prism, a reference beam reflector and a test beam reflector; the CCD camera is used for observing the isocratic interference fringes; The inclined linear moving mechanism is used for adjusting the inclined moving direction of the test beam reflector; And the displacement measuring device is used for measuring the moving distance of the test beam reflector along the inclined direction.
  7. 7. The apparatus of the angle measurement method based on the micro-wavelength difference dual-wavelength interference of claim 6, wherein the inclined linear movement mechanism comprises a rough adjustment translation stage, a first rotary stage, a linear translation stage, a second rotary stage and a plane mirror frame; The tilt movement direction of the test beam reflector is adjusted by the rotation of the first rotating table and the second rotating table, and the tilt direction displacement measurement of the test beam reflector is realized by the movement of the linear translation table.
  8. 8. The device for measuring the angle based on the micro-wavelength difference dual-wavelength interference according to claim 7, wherein the first rotating table and the second rotating table are respectively composed of a stationary table bottom and a rotatable table top, and the table top rotates in a 360-degree range around a central axis of the table bottom; the linear translation stage consists of a stationary stage bottom and a movable stage surface, wherein the stage surface moves in parallel along a central line relative to the stage bottom, and the moving distance or position is read.
  9. 9. The device for measuring the angle based on the micro-wavelength difference dual-wavelength interference of claim 7, wherein the test beam reflector is mounted on a plane reflector holder, the plane reflector holder is fixedly connected to a stand column, the plane reflector holder is used for adjusting the pitching of the mirror surface of the test beam reflector relative to a vertical plane, and the stand column is used for adjusting the height of the test beam reflector.

Description

Angle measurement method and device based on micro-wavelength difference dual-wavelength interference Technical Field The invention relates to the technical field of optical precision measurement, in particular to an angle measurement method and device based on micro-wavelength difference dual-wavelength interference. Background In the engineering practice of optical precision measurement, the angle measurement includes theodolite method (or telescope aiming method), double optical wedge reciprocal rotation method, auto-collimator method, moire fringe method, optical interference method (including equal thickness interference method and equal inclination interference method), laser Doppler frequency shift interference method, optical diffraction method, etc., the first four methods are based on geometrical optics principle, and the last three methods are based on physical optics principle. The angle measurement method based on the geometrical optics principle is generally large in angle measurement range, which can reach more than 10 degrees, but most of the angle measurement methods depend on a mechanical optical rotary table, and the accuracy of the angle measurement method depends on the accuracy of a dividing head, so that the angle measurement accuracy is low, and is generally less than 10 minutes. If the measurement accuracy is to be improved, the electronic digital counting device is to be assisted, which is more complicated. The angle is measured by a method based on a physical optical principle, the angle measurement range is generally smaller and is within 10 degrees, the measurement precision is higher by an interference or diffraction fringe counting method, and the precision can generally reach several seconds. In view of the contradiction between the low coherence angle measurement accuracy and the measurement range, it is necessary to develop an angle measurement method which is low in implementation cost, simple and convenient to operate, large in measurement range and high enough in accuracy. Disclosure of Invention (One) solving the technical problems Aiming at the defects of the prior art, the invention provides an angle measurement method and device based on micro-wavelength difference dual-wavelength interference, which has the advantages of simple and easy implementation, convenient installation and debugging of the device, suitability for high-precision measurement of micro angles and angles nearby 180 degrees, suitability for automatic analysis processing by using an image data analysis method with sensitive response, good accuracy and fuzzy or clear positioning of an interference pattern, capability of obtaining the order-of-magnitude precision of seconds by using a low-precision linear displacement mechanism, capability of solving the problems of larger measurement angle range, lower precision and smaller measurement angle precision by using a method based on a physical optical principle. (II) technical scheme In order to achieve the above purpose, the invention provides the following technical scheme that the angle measurement method based on the micro-wavelength difference dual-wavelength interference comprises the following steps: S1, generating equal-inclination interference fringes by a Michelson interferometer by adopting a dual-wavelength extended light source with a small wavelength difference; S2, using a linear moving mechanism capable of adjusting the inclination direction to enable the plane reflecting mirror of the test light beam to move along the inclination direction; S3, indirectly measuring the inclination angle by measuring the moving distance of the plane reflecting mirror when the interference fringes are the most blurred in two successive times in the moving process of the plane reflecting mirror along the inclination direction; and S4, calculating the measured angle according to the difference of the inclination angles measured twice. Preferably, the light emitted by the micro-wavelength difference dual-wavelength light source becomes an extended light source after passing through the ground glass screen, two coherent light beams are separated by the cube beam splitting prism, the upward reflected light beam is a reference light beam, and the light beam which directly passes through the cube beam splitting prism is a test light beam; The reference beam is reflected by the reference beam reflector and returns along the original path, and then reaches the CCD camera through the cubic beam splitting prism; The test beam is reflected by the test beam reflector and returns along the original path, and then is reflected by the cube beam splitting prism and reaches the CCD camera; The CCD camera focuses to observe the isocratic interference fringes of the extended light source towards infinity, or the naked eyes directly focus to observe the isocratic interference fringes towards infinity. Preferably, the test beam mirror is adjusted to move continuously along the c