A non-contact type device and method for measuring vibration

Abstract

The application relates to a non-contact type vibration measuring device and method, and the measuring device comprises a measuring system, a self-collimation system and a control system. The measuring system is used for generating and receiving a measuring light beam, and the position change amount of the light spot under the influence of vibration is measured at a high speed and in real time. The self-collimation system receives the output light of the measuring system and returns to the measuring system, and is used for obtaining the optical axis jitter amount under the influence of vibration. The control system is used for the overall control of the active device and the detector and data processing, and the measuring result is displayed and updated. The application is a non-contact type vibration measuring device with integrated receiving and transmitting functions, has strong noise robustness, can realize long-time and continuous monitoring at a high sampling frequency, has the advantages of high measuring precision and fast measuring speed, can extract the characteristic frequency and amplitude of vibration, and can be applied to the vibration measurement of a telescope system, aerospace, mechanical manufacturing and the like, and is especially suitable for the vibration measurement of a long-distance and weak reflection system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vibration measurement, in particular to a non-contact receiving and transmitting integrated vibration measurement device and method. BACKGROUND

[0002] The commonly used vibration ground measurement methods mainly include contact measurement method and non-contact laser vibration measurement. The contact measurement method is to paste acceleration sensor, displacement sensor and other detection devices on the target to be measured to collect and analyze data in real time. However, in order to measure the overall influence of micro-vibration on the system, multiple sensors need to be pasted on multiple devices, which makes the structure complex and the data processing tedious. The non-contact laser vibration measurement is to measure by using Doppler effect and interference technology, which has the advantages of high measurement precision and wide application range, but the structure is complex, and the echo signal strength is low when transmitting at a long distance, which affects the measurement precision. In addition, the vibration measurement method based on laser speckle uses the diffuse reflection light on the surface of the target to be measured to calculate the vibration information, which also has the problem that the laser echo is weak and difficult to detect when the measurement distance is far, and the vibration measurement precision is affected by the imaging lens. When the measurement precision requirement is high, the focal length of the imaging lens needs to be long enough, thereby increasing the system complexity. SUMMARY

[0003] In view of the problems in the prior art, the present application discloses a non-contact receiving and transmitting integrated vibration measurement device and method. A reflecting mirror is pasted on the surface of the structure to be measured or a self-collimation system is composed by using the reflecting element of the structure to be measured. The non-contact optical measurement method with receiving and transmitting functions is used to measure the change of the spot position affected by vibration in real time, which has the advantages of strong noise robustness, simple system structure and simple algorithm. The measurement system can also be applied to the field of fluid measurement. The flow rate of the fluid is calculated according to the change of the spot position.

[0004] The technical scheme adopted by the present application is as follows: a non-contact receiving and transmitting integrated vibration measurement device, which comprises a measurement system, a self-collimation system and a control system. The measurement system is composed of three parts, including a light source branch, a capture branch and a measurement branch, which are used to generate and receive a measurement beam, and measure the change of the spot position under the influence of vibration in high speed and real time. The self-collimation system receives the output light of the measurement system and returns it to the measurement system, which is used to obtain the optical axis jitter under the influence of vibration. The control system is used for the overall control and data processing of the active device and the detector, and displays and updates the measurement results. The active device is a device that changes the initial state by electric drive, such as a tilting mirror, a fast mirror, a deformable mirror, an electric translation stage, an electric rotation stage and other electrically controlled active devices.

[0005] The self-collimation mirror assembly is a single or multiple plane or curved mirror installed on the structure to be measured or a reflection element provided on the structure to be measured.

[0006] The self-collimation mirror assembly is a single or multiple plane or curved mirror installed on the structure to be measured or a reflection element provided on the structure to be measured.

[0007] The measurement system includes a light source branch, a capture branch, a measurement branch and a mirror surface, the mirror surface is a plane mirror or a corner cube mirror, and is used for adjusting and assembling the light source branch, the capture branch and the measurement branch to ensure the consistency of the optical axes of the branches.

[0008] The light source branch of the measurement system includes a laser, a beam shaping mirror group and a first beam splitter, the laser serves as a light source, the beam shaping mirror group is used for outputting light in a specific form, and the first beam splitter is used for splitting light, guiding part of the light to the self-collimation system and guiding part of the light to the mirror surface.

[0009] The measurement branch of the measurement system is composed of a second beam splitter, a matching mirror group and a detector, in order to ensure the measurement accuracy, the light spot needs to be completely received by the target surface of the detector, the second beam splitter is used for guiding the light to the measurement branch and the capture branch, the matching mirror group is used for enabling the light spot to be completely received by the detector, and the matching mirror group is a transmission type, reflection type or catadioptric type beam shrinking / expanding system or imaging system, the selection of the matching mirror group is determined by the measurement accuracy and the effective target surface of the detector, and the detector is a CCD, CMOS, PSD, four-quadrant detector or other photoelectric conversion device and is used for detecting the light spot.

[0010] The capture branch of the measurement system has a large field of view, is used for initial state detection of the system, assists in system debugging, is used for real-time monitoring, is composed of a mirror, an imaging mirror group and a far-field detector, the mirror is used for guiding the light to the capture branch, the imaging mirror group is a transmission system or a reflection system or a catadioptric system, is used for converging the light and imaging to the far-field detector, and the far-field detector is a CCD or CMOS image detection device and is used for detecting the light spot.

[0011] The control system controls each active device and the detector, calculates the change of the position of the light spot on the detector, and extracts the characteristic frequency and amplitude of the vibration source through Fourier transform.

[0012] The non-contact transmitting and receiving integrated vibration measuring device, when measuring, if the measuring system contains a reflecting mirror, the light emitted by the light source is reflected by the reflecting mirror and received by the detector as reference light, which is a homodyne measurement system; if the reflecting mirror is removed from the measuring system, that is, the measuring system does not contain the reflecting mirror, which is a heterodyne measurement system.

[0013] A non-contact transmitting and receiving integrated vibration measuring method, when measuring vibration by using the measuring device, includes the following steps:

[0014] Step 1): The light emitted by the laser passes through the beam shaping mirror group and is incident to the first beam splitter, a part of the light is transmitted to the reflecting mirror, reflected and then passes through the second beam splitter and the reflecting mirror into the measuring branch and the capturing branch, which is used for the alignment and calibration of the measuring system.

[0015] Step 2): The light emitted by the laser passes through the beam shaping mirror group and is incident to the first beam splitter, a part of the light is reflected and then incident to the guide mirror assembly to enter the autocollimation system, the light beam is coupled into the measuring system again through the guide mirror assembly after being reflected by the autocollimation mirror assembly, and is captured by the detectors of the measuring branch and the capturing branch through the first beam splitter, the second beam splitter and the reflecting mirror, respectively.

[0016] Step 3): The control system calculates the jitter of the optical system under the influence of vibration according to the change amount of the light spot position on the detectors of the measuring branch and the capturing branch, and calculates the characteristic frequency and amplitude through Fourier transform.

[0017] The non-contact transmitting and receiving integrated vibration measuring method, step 1) includes:

[0018] Measuring system alignment: the reflecting mirror of the measuring system is used to align the light source branch, the capturing branch and the measuring branch to ensure the consistency of the optical axes of the branches.

[0019] The non-contact transmitting and receiving integrated vibration measuring method, step 2) includes:

[0020] System overall alignment: after the alignment of the measuring system is completed, the system overall alignment is performed, and the light emitted by the light source branch is returned to the measuring system through adjusting the guide mirror assembly and the autocollimation mirror assembly, and is received by each measuring branch.

[0021] The non-contact transmitting and receiving integrated vibration measuring method, step 3) includes:

[0022] Parameter setting: the related parameters of the detectors in the measuring system are set by the control system, including exposure time, frame frequency, window size and gain.

[0023] Background calibration: turn off the laser, calibrate and measure the probe in the measurement system;

[0024] Measurement, display and data processing: turn on the laser, measure the vibration in real time, calculate the position change of the light spot and the characteristic frequency and amplitude of the system, and display and update the measurement results in real time.

[0025] The device and method for non-contact receiving and transmitting integrated vibration measurement have strong noise robustness, can realize long-time and continuous monitoring at a high sampling frequency, have the advantages of high measurement accuracy and fast measurement speed, can extract the characteristic frequency and amplitude of the vibration, and can be applied to vibration measurement in the fields of telescope systems, aerospace and mechanical manufacturing, and is especially suitable for vibration measurement of long-distance and weak reflection systems.

[0026] The advantages of the present application are:

[0027] (1) The present application effectively improves the light return efficiency through the autocollimation system, and is suitable for vibration measurement of long-distance and weak reflection targets.

[0028] (2) The present application can not only measure the position change of the light spot under the influence of vibration, but also extract the characteristic frequency and amplitude of the vibration source, and is used for guiding the development of vibration suppression scheme.

[0029] (3) The present application is a kind of receiving and transmitting integrated non-contact vibration measurement device and method, which has strong noise robustness, can realize long-time and continuous monitoring at a high sampling frequency, realizes high resolution, fast and real-time vibration measurement.

[0030] In summary, the present application solves the problem of vibration measurement of long-distance transmission and weak reflection targets, provides technical support for analyzing the imaging quality, pointing accuracy and stability of high-resolution telescope systems under the influence of vibration, and can also be applied to vibration measurement in the fields of aerospace and mechanical manufacturing. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a schematic diagram of a non-contact receiving and transmitting integrated vibration measurement device;

[0032] Figure 2 It is an optical system diagram of the first embodiment;

[0033] Figure 3 It is the frequency domain analysis result of the PSD measurement branch of the first embodiment;

[0034] Figure 4 It is the frequency domain analysis result of the high-speed acquisition CMOS measurement branch of the first embodiment.

[0035] 1, collimation mirror assembly; 2, guide mirror assembly; 3, mirror surface; 4, first beam splitter; 5, second beam splitter; 5-1, third beam splitter; 6, mirror. DETAILED DESCRIPTION

[0036] The present application will be described in detail below with reference to the drawings and specific embodiments. The scope of protection of the present application should include the entire content of the claims. The following examples are only used to illustrate the present application, but do not limit the scope of the present application. Similarly, the following examples are only part of the embodiments of the present application, not all embodiments, and all other embodiments without innovative improvements are within the scope of protection of the present application.

[0037] Example one:

[0038] Figure 1 A schematic diagram of a non-contact transceiver integrated vibration measuring device. Referring to Figure 1 A vibration measuring device of example one is designed, which is a large-aperture coaxial four-mirror telescope vibration measuring device. The optical system is as shown in Figure 2 The influence of mirror surface eccentricity on system image quality is much smaller than that of tilt, so only the tilt amount is concerned during measurement. The vibration measuring device includes a measurement system, a collimation system, and a control system. The measurement system consists of three parts, including a light source branch, a capture branch, and a measurement branch, which is used to generate and receive measurement beams, and measure the change in spot position under the influence of vibration in high speed and real time. The collimation system receives the output light of the measurement system and returns to the measurement system, which is used to obtain the optical axis jitter under the influence of vibration. The control system is used for the overall control of the active device and the detector and data processing, and real-time display and update of measurement results. The active device is a device that changes the initial state by electric drive, such as a tilt mirror, a fast mirror, a deformable mirror, an electric translation stage, an electric rotation stage, and other electrically controlled active devices.

[0039] The autocollimation system is composed of an autocollimation mirror assembly 1 and a guide mirror assembly 2. The autocollimation mirror assembly 1 is used to obtain the optical axis jitter under the influence of vibration; the guide mirror assembly 2 reflects the light beam output by the measurement light path into the autocollimation mirror assembly 1, and receives the reflected light from the autocollimation mirror assembly 1 and couples it into the measurement system. In the embodiment, the autocollimation mirror assembly 1 is composed of four plane mirrors M1, M2, M3 and M4 with a diameter of Φ100mm, and the four mirrors are respectively installed on the primary mirror, the secondary mirror, the third mirror and the fourth mirror support structure to simulate the respective mirror surfaces of the actual system. The M1 mirror and the guide mirror assembly 2 are active devices, which are designed as electrically adjustable tilt mirrors. This is because the transmission distance of the light path is very long, the interval between the primary mirror and the secondary mirror is 3676mm, the interval between the secondary mirror and the third mirror is 3352mm, the interval between the third mirror and the fourth mirror is 3413mm, and the interval between the fourth mirror and the guide mirror assembly is 3600mm. In order to ensure that the light path can be incident on the mirror M4 after being introduced by the guide mirror assembly 2, and can be received by the measurement light path after being reflected by the M1 mirror, the M1 mirror and the guide mirror assembly are designed as electrically adjustable tilt mirrors with a maximum tilt angle of ±0.2°.

[0040] The measurement system includes a light source branch, a capture branch, a measurement branch and a mirror surface 3. The mirror surface 3 is a plane mirror or a corner cube mirror, which is used for adjusting and assembling the light source branch, the capture branch and the measurement branch to ensure the consistency of the optical axes of the branches. In the embodiment, the mirror surface 3 is a plane mirror.

[0041] The light source branch includes a laser, a beam shaping mirror group and a first beam splitter 4. The laser serves as a light source, the beam shaping mirror group is used to output light with a specific shape, and the first beam splitter 4 is used for splitting light, guiding part of the light beam to the autocollimation system, and guiding part of the light beam to the mirror surface 3. In the embodiment, in order to ensure the measurement accuracy, the laser has high stability, and the power stability is better than 1%, and the maximum power is 300mw. The beam shaping mirror group is composed of a collimation system and a beam compression system. The collimation system is used to collimate the light beam output by the laser into parallel light, and the beam compression system is used to compress the light beam aperture. The divergence angle of the outgoing light beam is less than 0.5mrad, and the spot diameter is 2mm.

[0042] The measurement branch is composed of a second beam splitter 5, a matching mirror group and a detector. In order to ensure the measurement accuracy, the light spot needs to be completely received by the detector target surface. The second beam splitter 5 is used to guide the light beam into the measurement branch and the capture branch, and the matching mirror group is used to make the light spot be completely received by the detector. The matching mirror group is a transmission type, reflection type or catadioptric type beam compression / expansion system or imaging system, and the selection of the matching mirror group is determined by the measurement accuracy and the effective target surface of the detector. The detector is a CCD, CMOS, PSD, four-quadrant detector and other photoelectric conversion devices, which is used to detect the light spot. Compared with the prior art, the embodiment has the advantages of Figure 1 Figure 2 ​The measurement branch includes two branches, a first measurement branch and a second measurement branch. The first measurement branch is composed of the second beam splitter 5, a matching lens group and a detector, wherein the detector is a PSM2-20 PSD produced by the ONTRAK company, the photosensitive surface of the detector is 20mm*20mm, and the resolution is 0.5μm; in order to ensure that the light spot is completely received by the detector, the matching lens group adopts a first beam-reducing lens group with a beam-reducing ratio of 5. The second measurement branch is composed of the third beam splitter 5-1, a matching lens group and a detector, wherein the detector is a high-speed acquisition camera with a model of Cyclone-2-2000, the pixel size is 10μm, when the resolution is 1920*1080 pixels, the highest frame frequency is 2166fps, and when the resolution is 1280*860 pixels after windowing, the highest acquisition frame frequency is 2886fps; in order to ensure that the light spot is completely received by the detector target surface, the matching lens group adopts a second beam-reducing lens group with a beam-reducing ratio of 10.

[0043] The field of view of the capture branch is large, which is used for initial state detection of the system, auxiliary system debugging and real-time monitoring. The capture branch is composed of a reflecting mirror 6, an imaging lens group and a far-field detector. The reflecting mirror 6 is used for guiding the light beam into the capture branch, the imaging lens group is a transmission system or a reflection system or a catadioptric system, which is used for converging the light beam and imaging to the far-field detector, and the far-field detector is a CCD or CMOS image detection device, which is used for detecting the light spot. In the embodiment, the field of view of the capture branch is Φ0.2°, the imaging lens group adopts a lens with a focal length of 200mm, and the far-field detector adopts a Basler CMOS imaging camera.

[0044] The control system controls each active device and the detector, calculates the change of the position of the light spot on the detector, and extracts the characteristic frequency and amplitude of the vibration source through Fourier transform.

[0045] During measurement, if the system contains the reflecting mirror surface 3, the light emitted by the light source is reflected by the reflecting mirror surface 3 and received by the detector as reference light, which is a homodyne measurement system; if the reflecting mirror surface 3 is removed from the measurement light path, that is, the measurement system does not contain the reflecting mirror surface 3, which is a heterodyne measurement system. In the embodiment, the reflecting mirror surface 3 is removed from the light path by the electric translation stage during vibration measurement, so the measurement system is a heterodyne measurement system.

[0046] According to the embodiment of the present application, a non-contact transceiving integrated vibration measurement method is provided, which comprises the following steps:

[0047] Step 1): the light emitted by the laser passes through the beam shaping mirror group and is incident to the first beam splitter 4, wherein the beam shaping mirror group is composed of a collimating mirror group and a beam-reducing mirror group, a part of the light is transmitted to the mirror surface 3, and after being reflected, it passes through the first beam splitter 4, the second beam splitter 5, the third beam splitter 5-1, and the mirror 6 into the measurement branch and the capture branch, which is used for the adjustment and calibration of the measurement system.

[0048] Step 2): the light emitted by the laser passes through the beam shaping mirror group and is incident to the first beam splitter 4, wherein the beam shaping mirror group is composed of a collimating mirror group and a beam-reducing mirror group, a part of the light is transmitted to the mirror surface 3, and after being reflected, it passes through the first beam splitter 4, the second beam splitter 5, the third beam splitter 5-1, and the mirror 6 into the measurement branch and the capture branch, which is used for the adjustment and calibration of the measurement system.

[0049] Step 3): according to the change of the spot position of the measurement branch and the capture branch, the control system calculates the jitter of the optical system under the influence of vibration, and calculates the characteristic frequency and amplitude by Fourier transform of the change of the spot position.

[0050] In the measurement step 1), the following steps are included:

[0051] Measurement system adjustment: the mirror surface 3 of the measurement system is used to adjust the light source branch, the capture branch, and the measurement branch to ensure the consistency of the optical axes of the branches.

[0052] In the measurement step 2), the following steps are included:

[0053] System overall adjustment: after the measurement system adjustment is completed, the system overall adjustment is performed, and the light emitted by the light source is returned to the measurement system through the adjustment of the guide mirror assembly 2 and the M1 in the autocollimating mirror assembly 1, and is received by each measurement branch.

[0054] In the measurement step 3), the following steps are included:

[0055] Parameter setting: the related parameters of the detector in the measurement system are set by the control system, including exposure time, frame frequency, window size, and gain. In this embodiment, the measurement branch includes the first measurement branch and the second measurement branch, and the frame frequency of the PSD in the first measurement branch is set to 1000 Hz and the window size is set to 20 mm by the control system. 20mm, gain 1, exposure time of image detector CMOS in the second measurement branch is 100us, frame rate is 1000Hz, window size is 1280pixels*860pixels, gain is 1. In addition, the exposure time of the detector in the capture branch is set to 100us, the frame rate is 100Hz, and the window size is 1920pixels 1200pixels, gain 1;

[0056] Background calibration: turn off the laser, calibrate and measure the background of the detector in the measurement system;

[0057] Measurement, display and data processing: turn on the laser, measure the vibration in real time through the control system, calculate the position change of the light spot and the characteristic frequency and amplitude of the system, and display and update the measurement results in real time.

[0058] During vibration measurement, the refrigerator is turned on as a disturbance source, and the characteristic frequency and optical axis jitter of the measurement system are measured. For the first measurement branch, according to the change of the position of the light spot centroid along the x direction and the y direction under the influence of vibration output by the PSD detector, Fourier transform is performed, and the characteristic frequency and the corresponding amplitude are extracted in the frequency domain, as shown in Figure 3 For the second measurement branch, the change of the position of the light spot centroid on the detector is calculated, and Fourier transform is performed to extract the characteristic frequency and the corresponding amplitude, as shown in Figure 4 .

[0059] The device has strong noise robustness, can realize long-time and continuous monitoring at a high sampling frequency, has the advantages of high measurement accuracy and fast measurement speed, can extract the characteristic frequency and amplitude of vibration, and can be applied to vibration measurement in the fields of telescope systems, aerospace, mechanical manufacturing, etc., and is especially suitable for vibration measurement of long-distance and weak reflection systems.

[0060] The above only describes some embodiments of the present application, and does not limit the protection scope of the present application, and any equivalent device or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, are also included in the protection scope of the present application.

Claims

1. A non-contact transceiver integrated device for measuring vibration, characterized in that, The application relates to a vibration measurement system, which comprises a measurement system, a self-collimation system and a control system, the measurement system is composed of three parts, including a light source branch, a capture branch and a measurement branch, is used for generating and receiving a measurement light beam, and is used for measuring a light spot position change under vibration influence at high speed and in real time; the self-collimation system receives output light of the measurement system and returns to the measurement system, and is used for acquiring an optical axis jitter under vibration influence; the control system is used for overall control of active devices and detectors and data processing, and displays and updates measurement results, wherein the active devices are devices which change initial states through electric driving; The measurement system comprises a light source branch, a capture branch, a measurement branch and a mirror surface (3), the mirror surface (3) is a plane mirror or a corner cube mirror, is used for adjusting the light source branch, the capture branch and the measurement branch, and guarantees optical axis consistency of the branches; The capture branch of the measurement system has a large field of view, is used for initial state detection of the system, assists system debugging, is used for real-time monitoring, is composed of a mirror (6), an imaging lens group and a far field detector, wherein the mirror (6) is used for guiding the light beam into the capture branch, the imaging lens group is a transmission system or a reflection system or a catadioptric system, is used for converging the light beam and imaging to the far field detector, and the far field detector is a CCD or CMOS image detection device and is used for detecting the light spot.

2. The non-contact transceiving integrated vibration measuring device according to claim 1, wherein: The self-collimation system is composed of a self-collimation mirror assembly (1) and a guide mirror assembly (2), the self-collimation mirror assembly (1) is used for acquiring optical axis jitter under vibration influence; the guide mirror assembly (2) reflects the light beam output by the measurement system into the self-collimation mirror assembly (1), receives reflected light of the self-collimation mirror assembly (1) and couples the reflected light into the measurement system.

3. The non-contact transceiving integrated vibration measuring device according to claim 2, wherein: The self-collimation mirror assembly (1) is a single or multiple plane or curved mirror installed on a structure to be measured or a reflection element provided on the structure to be measured.

4. The non-contact transceiving integrated vibration measuring device according to claim 3, wherein: The light source branch of the measurement system comprises a laser, a light beam shaping lens group and a first beam splitter (4), the laser is used as a light source, the light beam shaping lens group is used for outputting a light beam with a specific shape, and the first beam splitter (4) is used for splitting light, guiding part of the light beam to the self-collimation system and guiding part of the light beam to the mirror surface (3).

5. The non-contact transceiving integrated vibration measuring device according to claim 4, wherein: The measurement branch of the measurement system is composed of a second beam splitter (5), a matching lens group and a detector, in order to guarantee measurement precision, the light spot needs to be completely received by a target surface of the detector, the second beam splitter (5) is used for guiding the light beam into the measurement branch and the capture branch, the matching lens group is used for making the light spot be completely received by the detector, is a transmission type, reflection type or catadioptric type beam shrinking / expanding system or imaging system, and selection of the matching lens group is determined by measurement precision and an effective target surface of the detector; and the detector is a CCD, CMOS, PSD, four-quadrant detector and other photoelectric conversion devices and is used for detecting the light spot.

6. The non-contact transceiving integrated vibration measuring device according to claim 1, wherein: The control system controls various active devices and detectors, calculates a change of the light spot position on the detector, and extracts characteristic frequencies and amplitudes of vibration sources through Fourier transform.

7. The non-contact transceiving integrated vibration measuring device according to claim 1, wherein: When measuring, if the measuring system contains the reflecting mirror (3), the light emitted by the light source is reflected by the reflecting mirror (3) and received by the detector as reference light, which is a reference measurement system; if the reflecting mirror (3) is removed from the measuring system, that is, the measuring system does not contain the reflecting mirror (3), which is a non-reference measurement system.

8. A method of contactless transceiving and measuring vibration, characterized by, The non-contact transceiving integrated vibration measuring device according to claim 5 is executed, comprising the following steps: Step 1): the light emitted by the laser passes through the beam shaping mirror group and is incident to the first beam splitter (4), a part of the light is transmitted to the reflecting mirror (3), and after being reflected, it enters the measuring branch and the capturing branch in turn through the second beam splitter (5) and the reflecting mirror (6), which is used for the adjustment and calibration of the measuring system; Step 2): the light emitted by the laser passes through the beam shaping mirror group and is incident to the first beam splitter (4), a part of the light is reflected and incident to the guide mirror assembly (2) to enter the autocollimation system, and after being reflected by the autocollimation reflecting mirror assembly (1), the light beam passes through the guide mirror assembly (2) again and is coupled into the measuring system, and is captured by the detectors of the measuring branch and the capturing branch through the first beam splitter (4), the second beam splitter (5) and the reflecting mirror (6) respectively; Step 3): the control system calculates the jitter of the optical system under the influence of vibration according to the change amount of the light spot position on the detectors of the measuring branch and the capturing branch, and calculates the characteristic frequency and amplitude through Fourier transform.

9. The method of claim 8, wherein the method is a non-contact method of measuring vibration. The step 1) comprises: Measuring system adjustment: the reflecting mirror (3) of the measuring system is used to adjust the light source branch, the capturing branch and the measuring branch to ensure the consistency of the optical axes of the branches.

10. The method of claim 8, wherein the method is a non-contact method of measuring vibration. The step 2) comprises: System overall adjustment: after the measuring system adjustment is completed, the system overall adjustment is performed, and the light emitted by the light source branch is returned to the measuring system through adjusting the guide mirror assembly (2) and the autocollimation reflecting mirror assembly (1) and is received by each measuring branch.

11. The method of claim 8, wherein the method is a non-contact method of measuring vibration. The step 3) comprises: Parameter setting: the related parameters of the detectors in the measuring system are set through the control system, including exposure time, frame frequency, window size and gain; Background calibration: the laser is turned off, and the detectors in the measuring system are calibrated and measured in the background; Measurement, display and data processing: the laser is turned on, the vibration is measured in real time, the position change amount of the light spot and the characteristic frequency and amplitude of the system are calculated, the measurement results are displayed and updated in real time.

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