CN212082583U

CN212082583U - Micro-vibration measuring device

Info

Publication number: CN212082583U
Application number: CN202021103648.9U
Authority: CN
Inventors: 李浩然; 张钰; 陈瑞林; 王祥文; 尹春阳; 王艺臻; 檀鹏程; 黄仙山
Original assignee: Anhui University of Technology AHUT
Current assignee: Anhui University of Technology AHUT
Priority date: 2020-06-15
Filing date: 2020-06-15
Publication date: 2020-12-04
Anticipated expiration: 2030-06-15

Abstract

The utility model discloses a micro-vibration measuring device belongs to vibrations and detects technical field. In view of the current michelson interferometer of measuring small displacement easily receives external environment and disturbs, the relatively poor problem of stability, the utility model provides a pair of microseism measuring device utilizes Wollaston prism to adjust the light beam, makes the reference light jet out the contained angle with the reverberation for a short time, and two light beams are located the environment the same, and when there is external disturbance, this two bundles of light will receive same interference to reduce the interference of external factor, made equipment more accurate to the measurement of small displacement. Simultaneously, do not receive the long-time effect of reverberation and lead to damaging in order to protect the laser instrument, the utility model discloses be provided with faraday optical rotation ware and polaroid between beam splitter prism and laser instrument, the light that reflects back passes through faraday optical rotation ware angle of adjustment after, is absorbed completely by the polaroid, can not get back to the laser instrument to protect equipment, practiced thrift the cost.

Description

Micro-vibration measuring device

Technical Field

The utility model relates to a vibrations detect technical field, more specifically say, relate to a micro-vibration measuring device.

Background

Vibration is one of the most basic physical phenomena, and is widely used in various fields such as daily life, industrial manufacturing, design and production, and the like. The earthquake caused by the earth crust movement is detected, geology and geological detection are enriched and developed, the earthquake detection and prevention capability of people is improved, and the disaster damage is reduced. The vibration generated by various machine tools in a production workshop during working is detected, a good detection means is provided for mechanical part failure analysis, and the fatigue failure rate of a mechanical device structure is reduced. Through carrying out vibration detection on parts of airplanes, ships and automobiles, the abrasion condition of each contact part of the parts can be judged, damaged parts can be replaced in time, the working precision of the parts can be improved, and accidents can be avoided. Therefore, the method has very important practical significance for measuring the vibration widely existing around the body.

Currently, most of the vibration measurement methods are as follows: conventional mechanical measurements, electrical measurements and optical measurements with laser as a tool. The mechanical measurement is a measurement means for analyzing the deformation of metal under different stresses, and the method has strong anti-interference capability and can effectively avoid the influence of the surrounding electrical environment, temperature and the like on the measurement. But the measuring frequency range of the method is narrow and the precision is low. The electrical measurement is a measurement means for measuring the amplitude by performing voltage-amplitude analysis on some special materials, such as semiconductor materials and mixed ceramic materials, and the method has high sensitivity but is very easy to be interfered by strong electromagnetic fields around. Meanwhile, the electrical measurement needs higher measurement conditions, and the purpose of safe production is difficult to achieve. The optical measurement method mainly uses laser as a tool, and combines interference and diffraction theories proposed by huygens, fresnel, fraunhofer and the like to realize the measurement of vibration, and the optical measurement instrument has the advantages of high precision, high resolution, wide frequency dynamic range, low electrical requirement and no power grid resonance, and becomes an effective detection means in the measurement field.

The michelson interferometer is a measuring tool for measuring micro displacement by using a laser interference method, but the traditional michelson interferometer has the problem of being easily interfered by an external environment, two beams of light which are interfered form an included angle of 90 degrees in space, the difference of the path environment of the two beams of light is large, when the path environment of one beam of light is changed, the optical path is changed, the measuring result is further influenced, and the influence is particularly obvious in some complex environments. Secondly, the measuring beam and the reference beam of the traditional Michelson interferometer can return to the laser in the original path, the laser used in some precise measurement is often very expensive, the light energy reflected back to the laser is high, and the laser can be damaged under the action of a long time.

Through retrieval, the Chinese patent number: ZL201710072946.2, the date of the authorized bulletin: the invention is named as follows on 1 day 2 month 2019: a single-frequency interference straightness error and a device and a method for measuring and compensating the position thereof are provided. After linearly polarized light beams output by the single-frequency laser of the application pass through the half-wave plate, the polarization direction is adjusted to be 45 degrees relative to a paper surface, the linearly polarized light beams after modulation are split by the first depolarizing beam splitter prism, transmitted light beams enter the Wollaston prism type laser single-frequency interferometer, and reflected light beams enter the Michelson type laser single-frequency interferometer. The Wollaston prism type laser single-frequency interferometer is used as a sensing unit, and formed interference signals of circular polarization and linear polarization are processed respectively, so that linearity errors and position measurement of the linearity errors are realized. The error detection and compensation part takes a Michelson type laser single-frequency interferometer as a sensing unit, analyzes the formed equal-thickness interference fringe image, realizes the measurement of the yaw angle and the pitch angle, compensates the measurement result of the linearity error and the position thereof according to the measured pitch angle, and improves the measurement precision of the linearity error and the position thereof. However, the application only uses the Wollaston prism to change the beam angle, does not consider the protection of the laser, and cannot well protect the equipment.

Disclosure of Invention

1. Technical problem to be solved by the utility model

In view of the current michelson interferometer that utilizes laser interferometry to measure small displacement easily receives external environment and disturbs, the relatively poor problem of stability, the utility model provides a pair of microseism measuring device utilizes Wollaston prism to adjust the light beam, makes two light beam environment the same, has reduced external interference, makes equipment more accurate to the measurement of small displacement.

2. Technical scheme

In order to achieve the above purpose, the utility model provides a technical scheme does:

the utility model discloses a micro-vibration measuring device, which comprises a laser, a beam expanding lens, a first reflecting mirror, a second reflecting mirror and a light screen; the beam expander and the laser are arranged at the same height; the first reflector and the second reflector are arranged on one side of the beam expander, which is far away from the laser, and reflect the projected light to the light screen; the optical fiber laser also comprises a beam splitter prism and a Wollaston prism; the beam splitter prism is arranged between the beam expander and the two reflectors and divides the light reflected by the first reflector and the second reflector into two beams; the Wollaston prism is arranged between the beam splitter prism and the two reflectors.

Furthermore, a first polaroid is arranged between the laser and the beam expander; and a second polaroid is arranged between the beam splitter prism and the Wollaston prism.

Furthermore, a Faraday rotator is arranged between the first polarizer and the beam expander.

Furthermore, a CCD camera is arranged beside the light screen and is connected with a computer to transmit signals to the computer.

Furthermore, the second reflector is fixedly arranged, and the first reflector is arranged close to the second reflector; the first reflector is movably arranged.

Furthermore, a vibration source is arranged on the first reflector and connected with a signal generator.

3. Advantageous effects

Adopt the technical scheme provided by the utility model, compare with existing well-known technique, have following beneficial effect:

(1) in view of the current michelson interferometer of measuring small displacement easily receives external environment and disturbs, the relatively poor problem of stability, the utility model provides a pair of microseism measuring device utilizes Wollaston prism to adjust the beam, makes reference light and reverberation jet out the contained angle little, and two light beams are the same in the environment of locating, have reduced external interference, make equipment more accurate to the measurement of small displacement.

(2) The laser instrument can be got back to in view of current michelson interferometer reverberation, and the light energy of reflection back laser instrument is higher, and long-time effect can lead to the fact the injury to the laser instrument, the problem of harm equipment, the utility model discloses be provided with faraday optical rotation ware and polaroid between beam splitter prism and laser instrument, the light that reflects back is absorbed completely by the polaroid after passing through faraday optical rotation ware angle of adjustment to can not get back to the laser instrument to protect equipment, practiced thrift the cost.

(3) The utility model discloses set up the CCD camera in light screen department to be connected CCD camera and computer, utilize the CCD camera to shoot the interference condition on the light screen, and carry out the analysis to the computer, reduced the error of artifical participation calculation, make the calculated result more accurate, reduced the human cost simultaneously, convenient to use.

Drawings

FIG. 1 is a schematic diagram of a conventional Michelson interferometer;

fig. 2 is a schematic structural diagram of the measuring device of the present invention.

The reference numerals in the schematic drawings illustrate:

1. a laser; 2. a first polarizing plate; 3. a Faraday rotator; 4. a beam expander; 5. a beam splitter prism; 6. a second polarizing plate; 7. a Wollaston prism; 8. a first reflector; 9. a second reflector; 10. a vibration source; 11. a semi-permeable and semi-reflective film; 12. A computer; 13. a signal generator; 14. a CCD camera; 15. a light screen.

Detailed Description

For a further understanding of the present invention, reference will be made to the following detailed description taken in conjunction with the accompanying drawings and examples.

Combine fig. 1, traditional michelson interferometer is become the pointolite by laser instrument 1 emission light through beam expander 4, divide into two bundles of light through transflective film 11 and throw respectively on first speculum 8 and second speculum 9, on two bundles of light reflection back projects the light screen 15 through transflective film 11, forms the interference image. The two beams of light L1 and L2 that interfere form an angle of 90 ° in space, and the difference between the path environments of the two beams of light is large. When the path environment of a beam of light changes, the optical path length changes, and the measurement result is affected, and the effect is particularly obvious in some complex environments. Secondly, the measuring beams and the reference beams L1 and L2 of the traditional Michelson interferometer return to the laser 1 in the original path, the laser 1 used in some precise measurement is often very expensive, the light energy reflected back to the laser 1 is high, and the laser 1 is damaged under the action of a long time.

The utility model discloses at first combine far field interference theory, carried out the emulation design and obtained emulation interference fringe image to the interferometer that designs. And secondly, a measurement system is set up by combining a simulation result and laboratory conditions, and each parameter of the optical system is adjusted in time, so that the stripe change is more obvious and the measurement is easy. Finally, the acquired interference fringe signals and the positions and the change conditions of the fringes are processed through MATLAB, so that the vibration condition can be well restored.

Example 1

Referring to fig. 2, the micro-vibration measuring device of the present embodiment includes a laser 1, a first polarizer 2, a faraday rotator 3, a beam expander 4, a beam splitter prism 5, a second polarizer 6, a wollaston prism 7, a first reflector 8, a second reflector 9, and a light screen 15. The beam expander 4 and the laser 1 are arranged at the same height. A first polaroid 2 and a Faraday optical rotator 3 are arranged between the beam expander 4 and the laser 1, the first polaroid 2 is arranged close to the laser 1, and the Faraday optical rotator 3 is arranged close to the beam expander 4. In the embodiment, the faraday optical rotator 3 and the first polarizing film 2 are arranged between the beam splitter prism 5 and the laser 1, and the reflected light is completely absorbed by the first polarizing film 2 after the angle of the reflected light is adjusted by the faraday optical rotator 3 and cannot return to the laser 1, so that the equipment is protected, and the cost is saved. The first reflector 8 and the second reflector 9 are arranged on the side of the beam expander 4 far away from the laser 1. Wherein, the second reflector 9 is fixedly arranged, and the first reflector 8 is arranged close to the second reflector 9; the first reflector 8 is movably arranged.

The beam splitter prism 5 is arranged between the beam expander 4 and the two reflectors and splits the light reflected by the first reflector 8 and the second reflector 9 into two beams. The Wollaston prism 7 is arranged between the beam splitter prism 5 and the two reflectors. It is known from the theory of interference that the interference pattern of the michelson interferometer is determined by the optical path difference between the reference light and the reflected light, and is represented by the equation (L) in fig. 1₂-L₁) Is influenced by (S) in FIG. 2₂-S₁) The influence of (c). In the embodiment, the wollaston prism 7 is added on the basis of the traditional michelson interferometer, at the moment, the optical path difference between the reference light and the reflected light is determined by S1 and S2, the directions of the two beams of light are almost the same, and the traveling paths of the two beams of light are almost the same, so when external interference exists, the two beams of light are subjected to the same interference, the optical paths on the two optical paths are simultaneously increased or reduced, the optical path difference is unchanged, namely the optical path difference of the two beams of light is only determined by an object to be measured, the interference of external factors is reduced, and the measurement of the micro displacement by the device is more accurate.

A second polarizer 6 is also disposed between the beam splitter prism 5 and the wollaston prism 7. The light reflected by the first reflecting mirror 8 and the second reflecting mirror 9 is projected on the light screen 15 via the second polarizing plate 6 and the beam splitter prism 5. A CCD camera 14 is arranged beside the light screen 15, and the CCD camera 14 is connected with the computer 12 and transmits signals to the computer 12. In the embodiment, the CCD camera 14 is used for shooting the interference condition on the optical screen 15 and transmitting the interference condition to the computer 12, the MATLAB is used for extracting information in the image and reversing the change condition of the optical path difference, so that the error of manual calculation is reduced, and the calculation result is more accurate. Meanwhile, the labor cost is reduced, and the use is convenient.

In this embodiment, a vibration source 10 is disposed on the first reflector 8, and the vibration source 10 is connected to a signal generator 13. In this embodiment, the vibration source 10 is a speaker.

Example 2

The micro-vibration measuring device of the present embodiment is the same as that of embodiment 1, and the use process in the micro-vibration measurement is as follows:

after laser light generated by the laser 1 passes through the first polarizer 2, the polarization direction of the light beam is parallel to the paper surface. Then, the polarization direction of the light is rotated clockwise by 45 ° by the faraday rotator 3 and coincides with the optical axis direction of the second polarizing plate 6. Then the light passes through the beam expander 4 and becomes a point light source, and the light source condition required by equal-inclination interference is met. The light continues through the beam splitter prism 5, the second polarizer 6, and reaches the wollaston prism 7, and the wollaston prism 7 splits the polarized light at an angle of 45 ° to the paper into two beams of light with a small included angle (usually around a few degrees), so that the two beams have nearly the same path. The polarization direction of one beam of light is vertical to the paper surface and is projected on a second reflecting mirror 9 (a fixed mirror) as reference light; the polarization direction of one beam of light is parallel to the paper surface, and the beam of light is projected on a first reflecting mirror 8 (movable mirror) to be used as signal light; a vibroseis source 10, in this embodiment a speaker is used as vibroseis source 10, and when a voltage signal is sent to vibroseis source 10 by signal generator 13, vibroseis source 10 generates vibrations to cause first mirror 8 to start moving back and forth along the direction of light ray S1. The light rays S1 and S2 start to return to the original path after being reflected by the two mirror surfaces, and at the moment, the two light beams are different in polarization direction and cannot generate interference phenomenon because the interference condition is not met. After the two beams pass through the second polarizer 6, the second polarizer 6 filters the two beams to make the polarization directions of the two beams the same and form an angle of 45 degrees with the paper surface. Then, two beams of light pass through the beam splitter prism 5, one part of the light is transmitted to the laser 1, and the other part of the light is reflected to the light screen 15; after light propagating towards the laser 1 passes through the faraday rotator 3, the polarization direction of the light beam rotates clockwise by 45 degrees again, the polarization direction at this time is perpendicular to the optical axis direction of the first polarizer 2, and the light is completely absorbed by the first polarizer 2, so that the laser 1 is protected. The light reflected on the light screen 15 starts to interfere, and since the first reflecting mirror 8 is vibrated all the time, the optical path length of the signal light is also changed, and a changed interference image will be seen on the light screen 15. This change is captured by the CCD camera 14 and the captured image is processed by MATLAB to invert the loaded signal content.

Example 3

The measuring device of this embodiment is the same as embodiment 1, and the device can also be used for detecting the flatness of the surface of a transparent uniform object: at S₁Or S₂The object to be detected is added into the light path and slowly moved, if the surface of the object is uneven, the interference fringes will change correspondingly, the interference fringes are collected by the CCD camera 14, and the condition of the surface of the object can be obtained after MATLAB processing.

The present invention and its embodiments have been described above schematically, and the description is not limited thereto, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching of the present invention, without departing from the inventive spirit of the present invention, the person skilled in the art should also design the similar structural modes and embodiments without creativity to the technical solution, and all shall fall within the protection scope of the present invention.

Claims

1. A micro-vibration measuring device comprises a laser (1), a beam expander (4), a first reflector (8), a second reflector (9) and a light screen (15); the beam expander (4) and the laser (1) are arranged at the same height; the first reflector (8) and the second reflector (9) are arranged on one side, away from the laser (1), of the beam expanding lens (4) and reflect the projected light to the light screen (15); the method is characterized in that: the optical fiber spectrometer also comprises a beam splitter prism (5) and a Wollaston prism (7); the beam splitter prism (5) is arranged between the beam expander (4) and the two reflectors and divides the light reflected by the first reflector (8) and the second reflector (9) into two beams; the Wollaston prism (7) is arranged between the beam splitter prism (5) and the two reflectors.

2. A microseismic measurement device according to claim 1 wherein: a first polaroid (2) is arranged between the laser (1) and the beam expander (4); and a second polaroid (6) is arranged between the beam splitter prism (5) and the Wollaston prism (7).

3. A microseismic measurement device according to claim 2 wherein: and a Faraday rotator (3) is arranged between the first polaroid (2) and the beam expander (4).

4. A microseismic measuring device according to any one of claims 1-3 wherein: and a CCD camera (14) is arranged beside the light screen (15), and the CCD camera (14) is connected with the computer (12) and transmits signals to the computer (12).

5. The micro-vibration measuring device of claim 4, wherein: the second reflector (9) is fixedly arranged, and the first reflector (8) is arranged close to the second reflector (9); the first reflector (8) is movably arranged.

6. The micro-vibration measuring device of claim 5, wherein: the first reflector (8) is provided with a vibration source (10), and the vibration source (10) is connected with a signal generator (13).