CN-116295103-B - Optical non-contact high-gradient profile measuring device

Abstract

The invention relates to an optical non-contact high-gradient profile measuring device, and belongs to the field of precise measurement. The device mainly comprises a precise motion executing module, a contour surface detecting module and a precise displacement measuring module. The invention uses a spectral dispersion confocal displacement measuring head with a certain installation inclination angle to realize the detection of a high-steepness profile, utilizes a two-dimensional orthogonal linear motion platform carrying measuring head to move according to a specified track, and combines the rotation of a measured part on a precise rotating shaft to realize the three-dimensional profile scanning. The device adopts the multi-axis double-frequency laser interference ranging of optical fiber light guide to carry out high-precision measurement on the displacement of the measuring head and realize the compensation of Abbe error by combining the reference frame technology. The measuring device has a simplified structure, and can realize ultra-precise measurement of high-gradient precise parts.

Inventors

• LI JIE
• YANG WENBO
• CHEN LIN

Assignees

• 中国科学院光电技术研究所

Dates

Publication Date

20260512

Application Date

20230317

Claims (4)

1. 1. An optical non-contact high-steepness profile measuring device is characterized by comprising a precise air floatation rotary table (1), a horizontal linear motion table (2), a vertical linear motion table (3), a spectral dispersion confocal displacement measuring head (4), a laser (5), an optical fiber (6), a beam expander (7), a first spectroscope (8), a second spectroscope (9), a third spectroscope (10), a second turning mirror (11), a first turning mirror (12), a third interference mirror (13), a second interference mirror (14), a first interference mirror (15), a first beam coupler (16), a second beam coupler (17), a third beam coupler (18), a fourth beam coupler (19), a first receiver (20), a second receiver (21), a third receiver (22), a fourth receiver (23), an X-axis displacement measuring reference (24), a Z-axis displacement measuring reference (25), a mechanical platform (26) and a controller (27), The precise air-floatation rotary table (1) is used for fixing a measured part (28) and executing precise rotary motion to realize the surface profile scanning of the measured part, and the rotary axis is defined as the Z axis of the measuring device; the horizontal linear motion table (2) is used for executing the horizontal direction motion and positioning of the spectral dispersion confocal displacement measuring head (4) so that the horizontal linear motion table can scan the outline of the measured part (28) along the radial direction, and the moving direction of the horizontal linear motion table is orthogonal to the Z axis; The vertical linear motion platform (3) is arranged on the horizontal linear motion platform (2) and is used for carrying the spectral dispersion confocal displacement measuring head (4) to move and position along the vertical direction, and the moving direction of the vertical linear motion platform is parallel to the Z axis; the controller (27) drives the horizontal linear motion table (2) and the vertical linear motion table (3) to be linked, and the spectral dispersion confocal displacement measuring head (4) is controlled to scan and measure according to a specified track, so that the profile of the measured part (28) is always in the effective travel range of the spectral dispersion confocal displacement measuring head (4) during scanning; The spectral dispersion confocal displacement measuring head (4) is arranged on the vertical linear motion table (3) and is used for carrying out non-contact detection on the surface profile information of the measured part (28); The laser (5) is used for providing frequency-stabilized double-frequency helium-neon laser, is used for carrying out interference measurement on the two-dimensional space position of the spectral dispersion confocal displacement measuring head (4), and the emergent laser of the laser (5) is conducted to a vertical linear motion table (3) in the device by an optical fiber (6); The beam expander (7) expands the laser beam which is guided by the optical fiber (6), and the laser beam after the beam expansion can be used for constructing an interference ranging light path; The first spectroscope (8) is used for separating laser into a reference beam and a measuring beam, the reference beam is used for suppressing environmental errors and interference in interferometry, and the measuring beam is used for realizing the measurement of Z-axis 1-path and X-axis 2-path displacement; The second beam splitter (9) is used for splitting the laser into 2 beams, one beam is used for Z-axis interference ranging, and the other beam is used for X-axis interference ranging; the third spectroscope (10) is used for dividing the X-axis measuring beam into 2 beams, wherein a 90-degree folded part of the beam is an X-axis measuring beam 1; the second turning mirror (11) is used for carrying out 90-degree turning on the laser beam transmitted by the third spectroscope (10) to form an X-axis measuring beam 2; the first turning mirror (12) is used for turning the laser beam reflected by the second beam splitter (9) by 90 degrees, and the direction of the turned laser beam is parallel to the Z axis of the device; the third interference mirror (13) is used for realizing the interference measurement of the X-axis measuring beam 2; The second interference mirror (14) is used for realizing the interference measurement of the X-axis measuring beam 1; The first interference mirror (15) is used for realizing the interference measurement of Z-axis displacement; The first beam coupler (16), the second beam coupler (17), the third beam coupler (18) and the fourth beam coupler (19) are used for receiving, coupling and transmitting optical signals of the third interference mirror (13), the second interference mirror (14), the first interference mirror (15) and the first spectroscope (8) to the first receiver (20), the second receiver (21), the third receiver (22) and the fourth receiver (23) so as to realize photoelectric conversion of reference signals and measurement signals; The X-axis displacement measurement reference (24) is fixed on a stable mechanical platform (26), and the plane normal direction of the X-axis displacement measurement reference is defined as the X axis of the measurement device and is used as a component part of a double-frequency laser interference ranging light path to realize the measurement of X-direction double-light path displacement; The Z-axis displacement measurement reference (25) is fixed on a stable mechanical platform (26), and the plane normal direction of the Z-axis displacement measurement reference is parallel to the Z axis and is used as a component part of a double-frequency laser interference ranging light path to realize measurement of Z-direction displacement; The controller (27) is used for realizing the programming motion of the precise air-float rotary table (1), the horizontal linear motion table (2) and the vertical linear motion table (3), the precise air-float rotary table (1), the horizontal linear motion table (2), the vertical linear motion table (3), the first receiver (20), the second receiver (21), the third receiver (22) and the fourth receiver (23) and analyzing and evaluating the output signals of the real-time acquisition, the processing and the measurement profiles.
2. 2. The optical non-contact high-steepness profile measuring device according to claim 1, wherein the laser light emitted by the laser (5) is guided into the measuring light path in an optical fiber transmission mode, so that the light path layout and the structural form of the device are simplified.
3. 3. The optical non-contact high-steepness profile measuring device according to claim 1, wherein the dual-frequency laser is divided into four beams, one beam is used as a reference signal for measurement to restrain environmental errors and interference, the other beam is used as a measuring signal of a Z axis to realize measurement of Z-directional displacement of the spectral dispersion confocal displacement measuring head (4), and the other beam is used as a measuring signal of an X-axis dual-light path to realize measurement of X-directional displacement of the spectral dispersion confocal displacement measuring head (4) and effectively compensate abbe errors for measurement.
4. 4. An optical non-contact high steepness profile measuring device according to claim 1, characterized in that the mounting of the spectrally dispersive confocal displacement probe (4) forms an inclination angle with the Z-axis to enlarge the steepness of the measurable profile.

Description

Optical non-contact high-gradient profile measuring device Technical Field The invention belongs to the field of precision measurement, and particularly relates to an optical non-contact high-gradient profile measuring device. Background Along with the wide development of precision engineering, the demands for precision parts are also continuously increased. The geometric outline precision of the part is often a core technical index, the quality and performance of the part are determined, and the key point of obtaining the high-quality outline is to provide reliable and effective precise measurement for guiding manufacturing and evaluating the quality, so that higher requirements are put on the precise outline measurement technology and device. Currently, commercial contour detection devices can be classified into a contact contour scanning method, a three-coordinate measurement method and a non-contact optical scanning method according to implementation methods. The contact profile scanning method uses a mechanical gauge head and a measurement reference standard to scan the profile of an object along a one-dimensional direction. During measurement, the measuring head is in contact with the measured surface, and during linear scanning, the mechanical measuring head is displaced due to the change of the profile height, the displacement can be accurately measured by the sensor, and the profile value can be calculated and obtained by combining the geometric relationship of the measuring head structure. The method has the advantages of simple structure and easy realization, but has the defects of small measurement dimension, complex adjustment, limited rise of the measurable contour, surface damage risk and the like. The three-coordinate measuring method is to touch the surface of the measured part through a mechanical or optical measuring head, move and record the space position of the measuring head by utilizing three linear motion shafts which are mutually perpendicular and are provided with grating rulers, and obtain the coordinates of measuring points so as to obtain the contour value. The three-coordinate measuring machine has strong universality and automation degree, but generally adopts a point-by-point measuring mode, has low measuring efficiency and sampling density, adopts a grating ruler to carry out displacement measurement, has limited precision and does not meet Abbe's principle. The traditional three-coordinate measuring machine is improved by Japanese pine corporation to improve the measuring precision, the three-dimensional displacement measuring precision is improved by adopting a reference frame combined with laser interference ranging, a displacement measuring light path is designed at the equal-height position of a measuring head contact point to reduce the measured Abbe error, and the contour measuring precision within the highest hundred nanometers can be realized. But is limited by a measuring head system structure, the measuring head needs to be replaced and certain precision is lost when the high-gradient profile is measured, meanwhile, the measured part size and the measurable sagittal height are limited to a certain extent by a measuring light path for eliminating Abbe errors, and the measuring efficiency of the instrument is low and the volume is huge due to a three-dimensional orthogonal measuring mode. A typical representative instrument for non-contact optical scanning is the Luphos series profilometer from taylor, usa. The instrument adopts a four-axis structure, and realizes the coverage scanning of the non-contact optical multi-wavelength interference measuring head on the surface of the measured part through two linear motion axes and one rotary axis. Meanwhile, the additionally added measuring head rotating shaft enables the measuring head to always measure along the outline normal direction of the measured part, and requirements on the working angle and the focal point size of the measuring head are reduced. The method has the advantages of compact structure, high measurement precision and high efficiency, meets Abbe's principle, but the additional rotating shaft increases the structural complexity and the implementation difficulty of the instrument. Disclosure of Invention The invention aims to solve the technical problem of providing a contour detection device with simple structure, high precision and large steepness aiming at the high-precision contour detection requirement in the manufacturing of precision parts. The technical scheme adopted for solving the technical problems is that the optical non-contact high-steepness profile measuring device comprises a precise air floatation rotary table 1, a horizontal linear motion table 2, a vertical linear motion table 3, a spectral dispersion confocal displacement measuring head 4, a laser 5, an optical fiber 6, a beam expander 7, a first spectroscope 8, a second spectroscope 9, a third spectroscope 10, a second turning mir