A laser non-contact object vibration detection and monitoring method

Abstract

The present application relates to a kind of laser non-contact object vibration detection and monitoring method.Utilize grating diffraction and single point array surface photoelectric sensor to obtain the displacement information of vibration image light spot, to establish mathematical model according to trigonometric function relationship and deduce the relationship of amplitude and image light spot displacement information, then judge vibration frequency in combination with oscilloscope waveform diagram, realize vibration detection.In addition, by monitoring the characteristic wave peak corresponding to the first-order diffraction fringe beam formed by the reflected light of detection object received by single point array surface photoelectric sensor in oscilloscope, the change of its period, amplitude and other relative to the waveform diagram of normal vibration state of object, the vibration of object can be monitored.The method introduces grating for measurement, uses single point array photoelectric sensor, solves the problem of high cost caused by using linear array photoelectric sensor for measurement in trigonometry and the problem of harsh use scene.

Description

Technical Field

[0001] This invention relates to the field of object vibration detection technology, and in particular to a laser non-contact object vibration detection and monitoring method. Background Technology

[0002] Currently, non-contact optical vibration measurement methods are widely used, but many problems still exist, such as:

[0003] (i) Some laser non-contact vibration measurement methods have high requirements for the test environment, requiring darkroom photography to obtain images carrying vibration information, which is not convenient for measuring the vibration of objects in general working environments; for example: holography, speckle method, moiré interferometry.

[0004] (ii) Another type of laser non-contact vibration measurement method has a working distance of only a few millimeters to tens of millimeters between the light source and the object being measured, which greatly limits the installation distance of the measuring device. In addition, multi-optical measurement devices have problems such as high cost, complex optical path and difficult operation, and small measurement range; for example: defocusing method and heterodyne interferometry method.

[0005] (III) The traditional laser triangulation method measures the position of the image point reflected after the incident beam shines on the object being tested. It analyzes the changes in the electrical signal of the photodetector caused by the displacement of the image point on the photosensitive surface of the photodetector due to the vibration of the object, and then analyzes the real-time changes in the signal to obtain the vibration of the object. However, detecting the displacement of the image point requires the use of a photodetector array, which is costly and has extremely high requirements for the consistency of the sensitivity of the optical probe, making it suitable for demanding applications. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a laser-based non-contact method for detecting and monitoring object vibration. Based on traditional laser triangulation, it utilizes grating diffraction and a single-array photoelectric sensor to acquire displacement information of the vibrating image point. A mathematical model is established based on trigonometric relationships to derive the relationship between amplitude and the displacement of the vibrating image point, thereby obtaining the vibration information of the detected object and enabling the detection and monitoring of object vibration. Specifically, the objective of this invention is achieved as follows:

[0007] A laser-based non-contact method for detecting and monitoring object vibration includes the following steps:

[0008] S1. Arrange the optical path by placing the line laser, grating, single-point array photoelectric sensor, and object to be detected on the same plane. The reflected light from the line laser illuminating the surface of the object passes through the grating and reaches the single-point array photoelectric sensor. Adjust the angles of each component so that the zeroth-order diffraction fringes generated by the reflected light from the stationary object after passing through the grating enter the single-point array photoelectric sensor perpendicularly.

[0009] S2, Data Acquisition: Connect the signal from the single-point array photoelectric sensor to an oscilloscope. Acquire the distance X between the zeroth-order diffraction fringe and the first-order diffraction fringe of the reflected light passing through the grating when the object is stationary, illuminating the plane of the single-point array photoelectric sensor. The object vibrates around a fixed point O. When the object is stationary, the reflected light point is A, and the distance between A and O is measured as h. When the object is stationary, the zeroth-order diffraction fringe of the reflected light passing through the grating reaches the receiving point of the single-point array photoelectric sensor as F, and the distance from point A to point F is measured as L. Then, vibrate the object and adjust the distance between the grating and the single-point array photoelectric sensor until the first-order diffraction fringe of the reflected light passing through the grating just enters the single-point array photoelectric sensor when the object vibrates. Record the distance D between the grating and the single-point array photoelectric sensor at this moment.

[0010] S3, vibration calculation, including vibration angle calculation and vibration frequency calculation. The vibration angle generated by the detected object relative to the stationary state when it vibrates is calculated using the collected data D, h, L, and X. The vibration frequency of the detected object is obtained by the real-time signal received when the reflected light from the detected object passes through the first-order diffraction fringes of the grating and swings into or out of the single-point array photoelectric sensor under vibration.

[0011] Furthermore, in step S1, when the object being detected is stationary, the angle difference between the line laser, grating, single-point array photoelectric sensor, and the object being detected is adjusted to ensure that the angle between the incident beam and the beam reflected by the object in the optical path is 90°; the vibration angle calculation in step S3 is divided into the following steps.

[0012] S3.1, Calculate the diffraction angle. Given the incident laser wavelength λ and the grating pitch d, use the diffraction formula... Calculate the diffraction angle θ between the first-order and zero-order diffraction fringes produced by the reflected light passing through the grating when the object is stationary;

[0013] S3.2, the trigonometric function relationship between the distances X and D and the diffraction angle θ is as follows: ;

[0014] S3.3, the vibration angle generated by the detected object relative to its stationary state is denoted as α. The vibration angle α is calculated using the following formula based on trigonometric functions and trigonometric relationships:

[0015] .

[0016] Furthermore, the vibration frequency in step S3 is calculated by using the vibration frequency f = 1 / t to obtain the vibration frequency of the object being tested, based on the time interval t of the periodic waveform of the vibration measurement signal from the oscilloscope.

[0017] Furthermore, the grating is placed on a high-precision displacement platform; a mirror reflection accessory is set on the surface of the object being detected to enhance the reflection of the incident light.

[0018] Further, in step S2, when the object being detected vibrates but the distance between the grating and the single-point array photoelectric sensor has not yet been adjusted, only the zeroth-order diffraction fringe moves on the single-point array photoelectric sensor. Therefore, the oscilloscope waveform only shows the periodic characteristic peak U0 corresponding to the zeroth-order diffraction fringe generated when the reflected light passes through the grating during the object's vibration. When the grating is adjusted until the first-order diffraction fringe generated after the reflected light passes through the grating during the object's vibration just enters the single-point array photoelectric sensor, in addition to the characteristic peak U0 corresponding to the zeroth-order diffraction fringe, the signal characteristic peak V0 corresponding to the first-order diffraction fringe also appears on the oscilloscope. The characteristic peak V0 displayed on the oscilloscope by the photoelectric signal received by the single-point array photoelectric sensor determines whether the first-order diffraction fringe generated after the reflected light passes through the grating just enters the single-point array photoelectric sensor. Then, by observing U0 and V0, it is determined whether the object is in an abnormal vibration state.

[0019] Furthermore, the abnormal vibration state includes abnormal vibration amplitude and abnormal vibration frequency of the detected object.

[0020] Furthermore, using the peak value P of the characteristic peak V0 during normal vibration of the object as a standard, when P changes by a value Δ... P ≥0.1P or Δ P When ≤-0.1P or P=0, the object being tested is in an abnormal state of vibration amplitude.

[0021] Furthermore, the time interval between the two characteristic peaks U0 is T, and when T changes by Δ... T ≥0.01T or

[0022] Δ T When the value is ≤-0.01T, the object being tested is in an abnormal vibration frequency state.

[0023] The working principle of this invention is as follows:

[0024] This scheme only considers the zeroth and first-order diffraction fringes of the grating. For example... Figure 3 As shown, when the object being detected is stationary, the beam emitted from the line laser, i.e., the incident light, is reflected after passing through point A on the vibration source. The reflected light enters the grating at point D and then diffracts. DF is the zeroth-order diffraction fringe beam when the object is stationary, and DK and DG are the first-order diffraction fringe beams when the object is stationary. The zeroth-order diffraction fringe beam DF directly enters the single-point array photoelectric sensor, which is connected to the oscilloscope.

[0025] like Figure 4As shown, the object is in a vibrating state, and at this point, the object undergoes an angle change of ∠AOB=α relative to its stationary state. Note that the optical path of the object in its stationary state is represented by dashed lines. In the stationary state, the measurement optical path requires a 90° angle between the incident and emitted beams. By positioning the object in its stationary state so that the incident and reflected beams are at 90°, it is easier to solve for the amplitude-related ∠AOB=α angle change by establishing a trigonometric similarity relationship. The laser beam emitted from the laser is reflected at point B on the object, and the reflected light is diffracted at grating E. EG represents the zeroth-order diffraction fringe beam in the vibrating state of the object, while EJ and EF represent the first-order diffraction fringe beams in the vibrating state. The intersection point between the reflected light from the stationary state and the reflected light from the vibrating state is C.

[0026] After the incident light passes through the grating, the zeroth and first order diffraction fringes have a fixed diffraction angle θ between them, according to the diffraction formula. The diffraction angle θ can be calculated, where λ is the wavelength of the incident laser and d is the grating pitch. ∠GDF and ∠KDF are the diffraction angles between the zeroth and first-order diffraction fringes of the object in its stationary state, and ∠FEG and ∠JEG are the diffraction angles between the zeroth and first-order diffraction fringes of the object in its vibrating state. These angles are derived from the diffraction formula. It can be seen that the values ​​of the four diffraction angles above are all θ, θ=∠GDF=∠KDF=∠FEG=∠JEG.

[0027] The distance X between the zeroth-order diffraction fringe DK and the first-order diffraction fringe DF on the plane of the single-point array photodetector when the object is at rest can be obtained by using the formula: (D = D - DF) = (D - DF) between the single-point array photodetector and the grating, and (D = D - DF) = (D - DF) / (D ... The solution is as follows: By adjusting the distance DF=D between the grating and the single-point array photodetector, the distance X between the zeroth-order diffraction fringe DF and the first-order diffraction fringe beam DK in the static state on the plane of the single-point array photodetector can be changed. When the distance between the grating and the single-point array photodetector is adjusted to a suitable value, the first-order diffraction fringe beam EF in the vibrating state just enters the single-point array photodetector, which is the original position of the zeroth-order diffraction fringe DF in the static state. In the vibrating state, the first-order diffraction fringe EF shifts to the left relative to the static first-order diffraction fringe beam DK; this shift on the plane of the single-point array photodetector is represented by FK. At this moment, when the distance DF=D between the grating and the single-point array photodetector is at a suitable value, the distance X between the first-order diffraction fringe DK and the zeroth-order diffraction fringe DF in the static state is equal to the shift FK of the first-order diffraction fringe EF in the vibrating state relative to the static first-order diffraction fringe beam DK. Therefore, when the distance DF=D between the grating and the single-point array photodetector is appropriate, the distance X between the zeroth-order diffraction fringe DF and the first-order diffraction fringe DK of the object in its static state on the plane of the single-point array photodetector can equivalently replace the displacement FK of the first-order diffraction fringe EF of the reflected beam in the vibrating state relative to its static first-order diffraction fringe DK on the surface of the single-point array photodetector, i.e., X=Dtanθ=Dtan∠KDF=FK. The displacement of the photoelectric point of the vibrating reflected image of the object on the plane of the single-point array photodetector obtained in the above manner is related to the change in angle ∠AOB=α between the vibrating object and its static state. The angle change between the vibrating state and the static state of the object can be solved using the laser triangulation method.

[0028] At this point, the distance AF=L between the reflected light spot of the object and the single-point array photoelectric sensor in the static state is measured. When the object vibrates around point O, the distance AO=h between the reflected light spot of the vibration source and point O is measured. In the vibrating state, the first-order diffraction fringe beam EF just enters the single-point array photoelectric sensor, and the distance DF=D between the photodetector and the grating is measured.

[0029] The amplitude of the object is represented by the change in angle ∠BOA=α. Based on the measured distances AF=L, AO=h, DF=D, and the diffraction angle θ between the first and zeroth order diffraction fringes obtained from the grating pitch and laser wavelength, the amplitude is... Figure 4 Using trigonometric functions and trigonometric similarity relationships, we obtain the following relationship for the vibration-related angle ∠BOA = α. Solving this relationship yields the angle α of the periodic vibration of the detected object:

[0030] .

[0031] The vibration frequency f of the object being detected is obtained by receiving real-time signals from the light source after the image light source is reflected and oscillated into or out of the light probe sensor. Based on the time interval t of the periodic waveform of the vibration measurement signal from the oscilloscope, the vibration frequency of the object being detected can be obtained by f=1 / t.

[0032] The method for determining whether the beam EF of the first-order diffraction fringe just enters the single-point array photoelectric sensor:

[0033] like Figure 5 , Figure 6 As shown, the single-point array sensor receives photoelectric signals, which are displayed on an oscilloscope, allowing the determination of whether the first-order diffraction fringe beam just enters the single-point array photoelectric sensor. When detecting object vibration, if the distance DF=D between the grating and the single-point array photoelectric sensor is not adjusted to an appropriate value, only the zeroth-order diffraction fringe moves on the single-point array photoelectric sensor. Therefore, the oscilloscope waveform only shows the periodic characteristic peak U0 corresponding to the zeroth-order diffraction fringe swinging in and out. When detecting object vibration, if the distance DF=D between the grating and the single-point array photoelectric sensor is adjusted to an appropriate value, in addition to the zeroth-order diffraction fringe moving on the single-point array photoelectric sensor, the first-order diffraction fringe also swings into the single-point array photoelectric sensor. Therefore, the oscilloscope waveform not only shows the periodic characteristic peak U0 corresponding to the zeroth-order diffraction fringe swinging in and out, but also shows the periodic characteristic peak V0 corresponding to the first-order diffraction fringe swinging in and out. Since the light intensity of the zeroth-order diffraction fringe is stronger than that of the first-order diffraction fringe, it can be seen from the waveform characteristic peak that U0>V0. Therefore, by adjusting the distance DF=D between the grating and the single-point array photoelectric sensor, when the first-order diffraction fringe swings in and out of the oscilloscope and the corresponding characteristic peak V0 appears, this is the moment when the first-order diffraction fringe beam EF just enters the single-point array photoelectric sensor, which also indicates that the distance between the grating and the single-point array photoelectric sensor has been adjusted to a suitable position.

[0034] The beneficial effects of this invention are as follows:

[0035] (i) The measurement is performed by introducing a grating. The distance between the zeroth and first order diffraction fringes formed by the reflected light passing through the grating when the object is at rest is used to illuminate the single-point array photoelectric sensor. This distance is used to replace the displacement of the image light point on the sensor array in the laser triangulation method. Instead, a single-point array photoelectric sensor is used, which solves the problems of high cost and harsh application scenarios when the triangulation method uses a linear array photoelectric sensor.

[0036] (ii) Linear light source measurement simplifies the optical path and makes it easy to adjust, allowing for use in various environments. The device features a large working distance, high resolution, a wide range of measurable vibration displacement, and a broad range of measurable frequencies.

[0037] (iii) The distance between the grating and the photodetector is adjusted by using a high-precision displacement platform to ensure the accuracy of the equivalent replacement image point displacement. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the stationary state of the object to be detected according to an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the vibration state of the object being detected according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram illustrating the principle of detecting the object in a static state according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram illustrating the principle of detecting the vibration state of the object according to an embodiment of the present invention;

[0042] Figure 5 The first light generated by the reflected light passing through the grating under the vibration state of the detected object, as described in the embodiments of the present invention.

[0043] A schematic diagram of the oscilloscope waveform when the diffraction stripe beam EF does not enter the single-point array photoelectric sensor;

[0044] Figure 6 This is a schematic diagram of the oscilloscope waveform when the first-order diffraction fringe beam EF generated by the reflected light passing through the grating in the vibration state of the object being detected enters the single-point array photoelectric sensor, as described in an embodiment of the present invention. Detailed Implementation

[0045] To make the technical means, creative features, and objectives of this invention easier to understand, the technical solution of this invention will be further explained below with reference to one embodiment and specific implementation of a laser non-contact object vibration detection and monitoring method.

[0046] like Figure 1-6 As shown, specific embodiments of the present invention are as follows:

[0047] A line laser, grating, and single-point array photodetector are mounted on an optical support, ensuring all three are at the same height. The grating is placed on a high-precision displacement platform to finely adjust its distance from the single-point array photodetector. The object to be detected is a ticker timer. With the ticker timer stationary, the angle difference between the three devices is adjusted to ensure a 90° angle between the incident beam and the beam reflected from the object in the optical path, meeting the measurement requirement. The distance AF=L between the reflected light A from the vibration source and the photodetector sensor in the stationary state is recorded using a ruler. The ticker timer spring vibrates around the O-axis, and the distance AO=h between the reflected light A from the ticker timer and the O-axis is recorded. A mirror sticker is applied to the surface of the ticker timer spring to increase the reflection of the incident light and ensure that the zeroth-order diffraction fringe DF reflected from the object directly enters the single-point array photodetector.

[0048] The ticker timer starts vibrating, and the output signal of the single-point array photodetector is connected to the oscilloscope to monitor the vibration signal of the ticker timer in real time. When the object being detected vibrates, but the distance between the grating and the single-point array photodetector has not yet been adjusted, only the zeroth-order diffraction fringe moves on the single-point array photodetector. Therefore, the oscilloscope waveform only shows the periodic characteristic peak U0 corresponding to the zeroth-order diffraction fringe swinging in and out of the grating when the reflected light from the object vibrates. The distance between the grating and the single-point array photodetector is adjusted by a high-precision displacement platform. When the first-order diffraction grating EF reflected by the ticker timer just enters the single-point array photodetector, the signal shows the characteristic peak V0 corresponding to the first-order diffraction fringe received by the detector. The adjustment of the displacement platform is then stopped, and the distance D between the grating and the photodetector at this time is recorded as a known condition.

[0049] pass The diffraction angle θ between the zeroth and first order diffraction fringes of the grating is calculated as a known condition. According to the principle, the distance between the single-point array photodetector and the grating is appropriate at this distance. At this distance, the distance X = D * tanθ between the zeroth order diffraction fringe DF and the first order diffraction fringe DK of the ticker timer in its stationary state on the plane of the single-point array photodetector can equivalently replace the displacement FK of the first order diffraction fringe EF of the reflected beam in the vibrating state relative to its stationary first order diffraction fringe DK on the surface of the single-point array photodetector. Using laser triangulation, all known conditions are substituted into the following formula to solve for the angle ∠BOA = α related to the vibration of the object:

[0050] .

[0051] The vibration frequency f of the ticker timer is obtained by receiving real-time signals from the single-dot array photoelectric sensor after the image light source reflected by the ticker timer is oscillated into or out of the sensor. The vibration frequency of the ticker timer can be obtained by f=1 / t based on the time interval t of the periodic waveform of the vibration measurement signal from the oscilloscope.

[0052] This technical solution enables real-time measurement of the vibration parameters of a ticker timer. Based on the steps described above, parameters indicating the periodic vibration of the ticker timer can be obtained: frequency f and the angle parameter α related to the vibration displacement. The vibration frequency f reflects the speed of the object's vibration cycle per second, and the angle α related to the vibration displacement reflects the magnitude of the object's swing displacement.

[0053] This technical solution can also sensitively monitor the real-time vibration status of periodically vibrating objects with known vibration parameters under normal operation, and can be used for real-time prevention and alarm of sudden changes in normal vibration. Besides comparing the vibration frequency and vibration displacement angle obtained through this technical solution with normal values, under the premise of ensuring the placement of the detection object, grating, and single-point array photoelectric sensor, the vibration angle can be more intuitively judged by the real-time waveform change of the characteristic peak V0 corresponding to the first-order diffraction fringe reflected by the ticker timer on the oscilloscope. When the vibration parameters of the ticker timer change, given the limited area of ​​the single-point array photoelectric sensor, the amount of light transmitted into the single-point array photoelectric sensor by the first-order diffraction fringe beam reflected by the ticker timer will increase or decrease compared to when the vibration parameters remain unchanged. Therefore, the change in the peak value P of the characteristic peak V0 corresponding to the first-order diffraction fringe is specifically analyzed. When the value P of the characteristic peak V0 changes by Δ... P A value ≥0.1P or the disappearance of the characteristic peak after an increase (P=0) indicates that the ticker timer is in an abnormal vibration state when the angle corresponding to the vibration displacement of the ticker timer increases (the amplitude of the object increases); when the characteristic peak V0 value changes by ΔP... P If the value is ≤-0.1P or the characteristic peak value disappears after decreasing (P=0), it indicates that the ticker timer is in an abnormal vibration state when the angle corresponding to the vibration displacement of the ticker timer decreases (the amplitude of the object decreases).

[0054] The frequency f and the angle parameter α related to the vibration displacement are independent of each other. The vibration frequency is measured by the time interval T between two periods of the vibration signal U0. When the time interval T of the periodic waveform changes by Δ... T When the value ≥0.01T or the interval between periodic waveforms increases, it indicates that the vibration frequency of the ticker timer has slowed down and is in an abnormal vibration state; when the time interval T of the periodic waveform changes by Δ... T A value ≤-0.01T or a decrease in the periodic waveform spacing indicates that the vibration frequency of the ticker timer has increased, indicating an abnormal vibration state. This method allows for the monitoring of whether the working condition of the object being tested, with known vibration parameters, is abnormal.

[0055] The vibration data of the ticker timer under different power supply voltages in this embodiment are as follows:

[0056] Table 1: Measurement data related to vibration displacement of the ticker timer under different voltages (∠BOA=α)

[0057]

[0058] Table 2: Measurement data of vibration frequency (frequency f) of the ticker timer under different voltages

[0059]

[0060] This scheme specifically measures the vibration-related angle ∠BOA=α and vibration frequency f of a ticker timer under different voltage power supplies ranging from 5V to 10V. The data shows that the vibration-related angle ∠BOA=α increases significantly with increasing voltage, while the vibration frequency remains relatively stable at 50Hz. Measuring the vibration parameters of the tested object under each power supply voltage yields a stable frequency f and the vibration-related angle ∠BOA=α. Furthermore, this device can be used for ticker timers whose vibration parameters are related to the power supply state. By measuring and detecting the object's vibration parameters (angle and frequency), the stability of the ticker timer's voltage can be monitored.

[0061] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A laser-based non-contact method for detecting and monitoring object vibration, characterized in that, Includes the following steps: S1. Arrange the optical path by placing the line laser, grating, single-point array photoelectric sensor, and object to be detected on the same plane. The reflected light from the line laser striking the surface of the object passes through the grating and reaches the single-point array photoelectric sensor. Adjust the angles of each component so that the zeroth-order diffraction fringes generated by the reflected light from the stationary object after passing through the grating enter the single-point array photoelectric sensor perpendicularly. S2, Data Acquisition: Connect the signal from the single-point array photoelectric sensor to an oscilloscope. Acquire the distance X between the zeroth-order diffraction fringe and the first-order diffraction fringe of the reflected light passing through the grating when the object is stationary, illuminating the plane of the single-point array photoelectric sensor. The object vibrates around a fixed point O. When the object is stationary, the reflected light point is A, and the distance between A and O is measured as h. When the object is stationary, the zeroth-order diffraction fringe of the reflected light passing through the grating reaches the receiving point of the single-point array photoelectric sensor as F, and the distance from point A to point F is measured as L. Then, vibrate the object and adjust the distance between the grating and the single-point array photoelectric sensor until the first-order diffraction fringe of the reflected light passing through the grating just enters the single-point array photoelectric sensor when the object vibrates. Record the distance D between the grating and the single-point array photoelectric sensor at this moment. S3, vibration calculation, including vibration angle calculation and vibration frequency calculation. The vibration angle generated by the detected object relative to the stationary state when it vibrates is calculated using the collected data D, h, L, and X. The vibration frequency of the detected object is obtained by the real-time signal received when the reflected light from the detected object passes through the first-order diffraction fringes of the grating and swings into or out of the single-point array photoelectric sensor under vibration.

2. The laser non-contact object vibration detection and monitoring method as described in claim 1, characterized in that: In step S1, with the object being detected stationary, the angle difference between the line laser, grating, single-point array photoelectric sensor, and the object being detected is adjusted to ensure that the angle between the incident beam and the beam reflected by the object in the optical path is 90°. The vibration angle calculation in step S3 is divided into the following steps. S3.1, Calculate the diffraction angle. Given the incident laser wavelength λ and the grating pitch d, use the diffraction formula... Calculate the diffraction angle θ between the first-order and zero-order diffraction fringes produced by the reflected light passing through the grating when the object is stationary; S3.2, the trigonometric function relationship between the distances X and D and the diffraction angle θ is as follows: ; S3.3, the vibration angle generated by the detected object relative to its stationary state is denoted as α. The vibration angle α is calculated using the following formula based on trigonometric functions and trigonometric relationships: 。 3. The laser non-contact object vibration detection and monitoring method as described in claim 1, characterized in that: The vibration frequency in step S3 is calculated by using the vibration frequency f = 1 / t to obtain the vibration frequency of the object being tested, based on the time interval t of the periodic waveform of the vibration measurement signal from the oscilloscope.

4. The laser non-contact object vibration detection and monitoring method as described in claim 1, characterized in that: The grating is placed on a high-precision displacement platform; a mirror reflection accessory is set on the surface of the object being detected to enhance the reflection of the incident light.

5. The laser non-contact object vibration detection and monitoring method as described in claim 1, characterized in that: In step S2, when the object being detected vibrates but the distance between the grating and the single-point array photoelectric sensor has not yet been adjusted, only the zeroth-order diffraction fringe moves on the single-point array photoelectric sensor. Therefore, the oscilloscope waveform only shows the periodic characteristic peak U0 corresponding to the zeroth-order diffraction fringe generated when the reflected light passes through the grating during the object's vibration. When the grating is adjusted until the first-order diffraction fringe generated after the reflected light passes through the grating during the object's vibration just enters the single-point array photoelectric sensor, the oscilloscope displays not only the characteristic peak U0 corresponding to the zeroth-order diffraction fringe but also the signal characteristic peak V0 corresponding to the first-order diffraction fringe. The characteristic peak V0 displayed on the oscilloscope by the photoelectric signal received by the single-point array photoelectric sensor determines whether the first-order diffraction fringe generated after the reflected light passes through the grating just enters the single-point array photoelectric sensor. Then, by observing U0 and V0, it is determined whether the object is in an abnormal vibration state.

6. The laser non-contact object vibration detection and monitoring method as described in claim 5, characterized in that: The abnormal vibration state includes abnormal vibration amplitude and abnormal vibration frequency of the detected object.

7. The laser non-contact object vibration detection and monitoring method as described in claim 6, characterized in that: Using the peak value P of the characteristic peak V0 during normal vibration of the tested object as the standard, when P changes by Δ... P ≥0.1P or Δ P When ≤-0.1P or P=0, the object being tested is in an abnormal state of vibration amplitude.

8. The laser non-contact object vibration detection and monitoring method as described in claim 6, characterized in that: The time interval between the two characteristic peaks U0 is T. When T changes by Δ T ≥0.01T or Δ T When the value is ≤-0.01T, the object being tested is in an abnormal vibration frequency state.

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