Vibration displacement measurement method and system based on multi-source data fusion

Abstract

The invention discloses a vibration displacement measurement method and system based on multi-source data fusion, and belongs to the technical field of vibration measurement. The vibration displacement measurement method based on multi-source data fusion comprises the following steps: acquiring motion sequence images of an elastic tube and a rigid tube through a high-speed camera, and acquiring a vibration acceleration signal of the elastic tube through an acceleration sensor; displacement tracks, obtained by the high-speed camera, of the elastic tube and the rigid tube are extracted, and a flow-induced vibration displacement time travel curve of the elastic tube is separated; performing frequency domain analysis on the displacement track data, and determining frequency bands of the rigid tube and the elastic tube; carrying out band-pass filtering on signals of the acceleration sensor based on a frequency band of flow-induced vibration, and compensating an error of an integral trend term of the acceleration sensor by utilizing time domain displacement data of the rigid tube; and carrying out secondary integration on the filtered acceleration sensor signal, and outputting corrected displacement information. By adopting the vibration displacement measurement method and measurement system based on multi-source data fusion, the problem that effective unification of measurement precision and engineering applicability cannot be realized by an existing vibration measurement method can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration measurement, and in particular, to a vibration displacement measurement method and measurement system based on multi-source data fusion. Background Art

[0002] In equipment such as steam generators of nuclear power plants, fluid-induced vibration caused by fluid flowing across tube bundles is one of the main inducements leading to the failure of tube bundle structures. To prevent engineering accidents and improve the theoretical system of fluid-induced vibration, it is urgent to develop high-precision vibration displacement measurement technology.

[0003] There are mainly two technical routes for existing vibration displacement measurement:

[0004] (1) Non-contact measurement method based on high-speed photography: The motion trajectory of the object to be measured is captured by a high-speed camera device, and the displacement time history curve is obtained through image processing. Although this method can achieve intuitive measurement, it has significant limitations: First, to achieve effective recognition, it is necessary to equip high-frame-rate, high-resolution camera devices and supporting lighting systems, resulting in high equipment costs; Second, it is sensitive to environmental parameters such as the shooting field of view and lighting conditions, and its applicability is limited in closed spaces or complex working conditions; Third, continuous shooting with high resolution generates a large amount of data, causing storage and processing pressure.

[0005] (2) Integration measurement method based on acceleration sensors: The vibration signal is collected by a piezoelectric acceleration sensor, and the displacement information is obtained through a second-order integration operation. Although this method has engineering advantages such as low cost and easy deployment, there are two key technical bottlenecks in practical applications: First, environmental noise interference causes trend term errors in the integration process, directly affecting the displacement reconstruction accuracy; Second, the selection of the filtering frequency band in the acceleration signal preprocessing link overly relies on empirical parameters and lacks an objective correction mechanism, easily resulting in the loss of effective signals or the residue of noise.

[0006] The current technical dilemma is that although the high-speed photography method can provide reference data, its engineering practicability is insufficient, while the acceleration integration method is easy to implement but has accuracy defects; it is impossible to effectively unify measurement accuracy and engineering applicability. Summary of the Invention

[0007] The purpose of the present invention is to provide a vibration displacement measurement method and measurement system based on multi-source data fusion, so as to solve the problem that the existing vibration measurement methods cannot effectively unify measurement accuracy and engineering applicability.

[0008] To achieve the above purpose, the present invention provides a vibration displacement measurement method based on multi-source data fusion, including the following steps:

[0009] S1. Obtain the motion sequence images of the flexible tube and the rigid tube through a high-speed camera, and simultaneously collect the vibration acceleration signals of the flexible tube through an acceleration sensor;

[0010] S2. Extract the displacement trajectories of the flexible tube and the rigid tube respectively, and separate the time history curve of the fluid-induced vibration displacement of the flexible tube through displacement vector operation;

[0011] S3. Conduct frequency-domain analysis on the displacement trajectory data of the rigid tube and the flexible tube respectively, establish the power spectral density functions of the rigid tube and the flexible tube; determine the frequency bands of the rigid tube and the flexible tube;

[0012] S4. Determine the main frequency of the rigid tube, the main frequency of the flexible tube and the main frequency of the fluid-induced vibration according to the power spectral density functions of the rigid tube and the flexible tube, and judge whether the main frequency of the rigid tube and the main frequency of the fluid-induced vibration meet the frequency decoupling condition;

[0013] S5. Perform band-pass filtering on the acceleration sensor signal based on the frequency band of the fluid-induced vibration, and compensate the error of the integral trend term of the acceleration sensor by using the time-domain displacement data of the rigid tube;

[0014] S6. Integrate the filtered acceleration sensor signal twice and output the corrected displacement information.

[0015] Preferably, the S2 is specifically:

[0016] S21. Perform gray conversion and region cropping processing on the original video frames of the motion sequence images;

[0017] S22. Extract the time-domain displacement trajectory function f1(x, y) of the rigid tube and the time-domain displacement trajectory function f2(x, y) of the flexible tube respectively through motion tracking software;

[0018] S23. Construct a displacement vector operation model to obtain the time-domain displacement trajectory function of the fluid-induced vibration of the flexible tube, and obtain the time history curve of the fluid-induced vibration displacement of the flexible tube;

[0019] The displacement vector operation model is:

[0020] f(x, y) = f1(x, y) - f1(x, y);

[0021] Among them, f(x, y) is the time-domain displacement trajectory function of the fluid-induced vibration of the flexible tube.

[0022] Preferably, the S3 is specifically:

[0023] S31. Establish a frequency-domain decoupling analysis model, perform continuous Fourier transform on the displacements of the rigid tube and the flexible tube respectively to obtain the frequency-domain expressions; the frequency-domain decoupling analysis model is:

[0024]

[0025] Among them, X(ω) is the frequency-domain function, ω is the angular frequency, t is the time variable, j is the imaginary unit, and x(t) is the displacement at time t;

[0026] S32. Calculate the discrete spectrum using the fast Fourier transform algorithm;

[0027]

[0028] Among them, X[k] is the discrete spectrum, N is the sampling capacity, k is the frequency, n is the number of sampling times, x[n] is the discrete time-domain signal, and the frequency resolution Δf = f s / N, f s is the sampling frequency;

[0029] S33. Normalize the amplitude of the discrete spectrum to establish a standardized power spectral density function;

[0030] P(ω) = |X(ω)| 2 / 2πT;

[0031] Among them, T is the signal observation duration.

[0032] Preferably, in the S4, the frequency decoupling condition is that the main frequency of the rigid pipe is greater than or less than the main frequency of the fluid-induced vibration by ±50%.

[0033] Preferably, in the S5, the passband boundary of the band-pass filter is the main frequency of the fluid-induced vibration ±50%.

[0034] Preferably, in the S5, the error of compensating the integral trend term of the acceleration sensor by using the time-domain displacement data of the rigid pipe is specifically:

[0035] Align the integral displacement of the acceleration sensor with the time-domain displacement data of the rigid pipe, and calculate and eliminate the trend term offset of the integral displacement of the acceleration sensor.

[0036] A measurement system for the above vibration displacement measurement method based on multi-source data fusion, comprising:

[0037] A water tank for storing fluid;

[0038] A gas compressor for providing a gas source;

[0039] An experimental pipe for mixing fluid and gas and measuring vibration displacement. The experimental pipe is connected to the water tank through a circulation pipeline, and the gas compressor is connected to the experimental pipe through a connecting pipe; a rigid pipe and an elastic pipe are arranged in the experimental pipe;

[0040] A high-speed camera 5, located on one side of the experimental pipe, for acquiring the motion sequence images of the elastic pipe and the rigid pipe;

[0041] An acceleration displacement sensor is provided at the free end of the elastic tube and is triggered synchronously with the high-speed camera 5;

[0042] A data processor is electrically connected to both the high-speed camera 5 and the acceleration displacement sensor, and performs displacement separation, frequency band analysis processing on the motion sequence images, and integral correction processing on the acceleration displacement data.

[0043] Preferably, both ends of the rigid tube are fixed inside the experimental tube; the elastic tube is a stepped tube, the smaller-diameter section of the elastic tube is fixed inside the experimental tube, and the larger-diameter section of the elastic tube is the free section.

[0044] Preferably, the rigid tube and the elastic tube are made of the same material. The rigid tube is a solid tube, and the elastic tube is a hollow tube.

[0045] Preferably, the optical axis of the high-speed camera 5 is located on the central plane of the rigid tube and the elastic tube.

[0046] The advantages and positive effects of the vibration displacement measurement method and measurement system based on multi-source data fusion according to the present invention are as follows:

[0047] 1. Based on the environmental vibration separation technology of the rigid tube, the present invention effectively eliminates the coupling influence of the equipment foundation vibration on the measurement result, which is beneficial to improving the measurement accuracy.

[0048] 2. By using the fluid-induced vibration displacement data of the elastic tube to optimize the frequency band and compensate the integral error in the acceleration signal processing process, the present invention controls the maximum displacement measurement error within 5%, improving the accuracy of acceleration displacement measurement.

[0049] 3. Breaking through the strict requirements of the traditional high-speed photography method for shooting conditions, the present invention expands the applicable scenarios of the system in the 0 - 250 Hz wide frequency band range while retaining the benchmark calibration function.

[0050] 4. By guiding the filtering process with the frequency band characteristic parameters, the present invention reduces the amount of invalid data calculation, increases the vibration signal processing speed by 15 times, and reduces the storage requirement by 90%.

[0051] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0052] Figure 1 It is a flowchart of the measurement method according to an embodiment of the present invention;

[0053] Figure 2 It is a schematic structural diagram of the measurement system according to an embodiment of the present invention;

[0054] Figure 3 It is a schematic structural diagram of the elastic tube in the measurement system according to an embodiment of the present invention;

[0055] Figure 4 Motion sequence images of the elastic tube and the rigid tube in the embodiments of the present invention;

[0056] Figure 5 An image after grayscale conversion and region cropping processing in the embodiments of the present invention;

[0057] Figure 6 Displacement time history curves of the rigid tube and the elastic tube in the embodiments of the present invention; among them, the measured value is the displacement time history curve of the elastic tube, the environmental interference is the displacement time history curve of the rigid tube, and the corrected value is the displacement time history curve of the fluid-induced vibration of the elastic tube;

[0058] Figure 7 Frequency domain characteristic diagrams of the rigid tube and the elastic tube in the embodiments of the present invention; among them, the measured value is the frequency domain characteristic diagram of the elastic tube, the environmental interference is the frequency domain characteristic diagram of the rigid tube, and the corrected value is the frequency domain characteristic diagram of the fluid-induced vibration of the elastic tube;

[0059] Figure 8 Results of the displacement data of the fluid-induced vibration of the elastic tube calculated by the corrected acceleration sensor and the displacement data of the fluid-induced vibration of the elastic tube obtained by using a high-speed camera in the embodiments of the present invention;

[0060] Figure 9 Displacement data of the fluid-induced vibration of the elastic tube without correction in the present invention.

[0061] Reference numerals

[0062] 1. Base; 2. Water tank; 3. Gas compressor; 4. Experimental tube; 5. High-speed camera; 6. Elastic tube; 7. Acceleration sensor. Detailed implementation manners

[0063] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0064] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. In case of any inconsistency, the meaning stated in this specification or the meaning derived from the content recorded in this specification shall prevail. Additionally, the terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application. For the purpose of accurately describing the technical content in this application and for accurately understanding the present invention, the following explanations or definitions are given to the terms used in this specification before describing the specific embodiments:

[0065] The following will describe in detail the embodiments of the present invention with reference to the accompanying drawings.

[0066] Embodiment

[0067] As Figure 1 shown. A vibration displacement measurement method based on multi-source data fusion includes the following steps:

[0068] S1. Obtain the motion sequence images of the elastic tube 6 and the rigid tube through the high-speed camera 5, as Figure 4 shown. At the same time, collect the vibration acceleration signal of the elastic tube 6 through the acceleration sensor 7.

[0069] Use a Photron FASTCAM type high-speed camera, whose optical axis is strictly coplanar with the central plane of the elastic tube 6 and the rigid tube to eliminate the three-dimensional projection error caused by parallax. Camera parameter calibration: Set the resolution to 2048×2048 pixels, the frame rate to 500fps, and perform non-uniformity correction through the built-in blackbody radiation source. The optical system is adjusted to obtain a clear imaging area with a depth of field of 15mm at an f / 5.6 aperture to ensure that the full-stroke movement of the tube bundle is within the focal plane. Synchronously configure a PCB 3305A type ICP acceleration sensor 7 (sensitivity 50mV / (m·s-2), frequency response 0.5 - 5000Hz±3dB), and perform AD conversion through a DH5922 type dynamic signal analyzer. The sampling frequency is set to 500Hz (meeting the Nyquist-Shannon sampling theorem). The signal synchronous acquisition of the high-speed camera 5 and the acceleration sensor 7 is realized through a DH5922 dynamic data acquisition system, and the synchronous error ≤0.1ms.

[0070] S2. Extract the displacement trajectories of the elastic tube 6 and the rigid tube respectively, and separate the time history curve of the fluid-induced vibration displacement of the elastic tube 6 through displacement vector operation.

[0071] Specifically:

[0072] S21. Perform gray-scale conversion and region cropping processing on the original video frames of the motion sequence images, as Figure 5 shown.

[0073] The original video frames contain a large amount of information, but there may be interference factors such as noise and redundant backgrounds, which are not conducive to the subsequent identification of the movement trajectories of the pipe fittings. Therefore, gray-scale conversion and regional cropping processing are performed on the original video frames. Gray-scale conversion converts the color image into a gray-scale image, reducing the complexity brought by color information while retaining the brightness characteristics of the image, facilitating subsequent processing. Regional cropping selects the area containing the rigid pipe and the elastic pipe 6, removes the irrelevant background parts, optimizes the acquisition of the boundary features of the rigid pipe and the elastic pipe 6, and improves the efficiency and accuracy of subsequent processing.

[0074] S22. Respectively extract the time-domain displacement trajectory function f1(x, y) of the rigid pipe and the time-domain displacement trajectory function f2(x, y) of the elastic pipe 6 through existing motion tracking software.

[0075] Since the rigid pipe is rigidly connected to the test bench and has a high structural stiffness, its movement trajectory only reflects the vibration characteristics of the equipment foundation. The time-domain displacement trajectory function f1(x, y) of the rigid pipe represents the changes in the x and y directions of the equipment foundation vibration over time. The movement response of the elastic pipe 6 is the result of the coupling of fluid-induced vibration and environmental vibration. The extracted time-domain displacement trajectory function f2(x, y) contains the displacement changes in the x and y directions under the combined action of these two factors.

[0076] S23. Construct a displacement vector operation model to obtain the fluid-induced vibration displacement trajectory function of the elastic pipe 6 and obtain the time history curve of the fluid-induced vibration displacement of the elastic pipe 6. As Figure 6 shown.

[0077] The displacement vector operation model is:

[0078] f(x, y) = f2(x, y) - f1(x, y);

[0079] where f(x, y) is the fluid-induced vibration displacement trajectory function of the elastic pipe 6.

[0080] In order to obtain the time history of the vibration displacement of the elastic pipe 6 under the action of fluid-induced vibration, it is necessary to eliminate the influence of environmental vibration. Since f1(x, y) represents the displacement caused by the equipment foundation vibration (i.e., environmental vibration), and f2(x, y) is the displacement of the elastic pipe 6 under the combined action of fluid-induced vibration and environmental vibration, subtracting the two can effectively eliminate the common-mode interference of environmental vibration and obtain the time history f(x, y) of the vibration displacement of the elastic pipe 6 caused only by fluid-induced vibration.

[0081] S3. Respectively perform frequency-domain analysis on the displacement trajectory data of the rigid pipe and the elastic pipe 6, establish the power spectral density functions of the rigid pipe and the elastic pipe 6; determine the frequency bands of the rigid pipe and the elastic pipe 6.

[0082] Specifically:

[0083] S31. To quantify the spectral characteristics of the vibration signals of the rigid pipe and the elastic pipe 6, a frequency-domain decoupling analysis model is established. The displacements of the rigid pipe and the elastic pipe 6 are respectively subjected to continuous Fourier transform to obtain frequency-domain expressions.

[0084] The frequency-domain decoupling analysis model is as follows:

[0085]

[0086] where X(ω) is a frequency-domain function, ω is the angular frequency, t is the time variable, j is the imaginary unit, and x(t) is the displacement at time t.

[0087] Through this transformation, the distribution of the signal in different frequency components can be analyzed, and it can be understood which frequencies the signal contains and the relative intensities of each frequency component.

[0088] S32. Since the actually collected signal is discrete, the time-domain signal needs to be discretized. After discretization, the discrete spectrum is calculated using the fast Fourier transform algorithm. The formula is as follows:

[0089]

[0090] where X[k] is the discrete spectrum, N is the sampling capacity, k is the frequency, n is the sampling number, x[n] is the discrete time-domain signal, and the frequency resolution Δf = f s / N, and f s is the sampling frequency.

[0091] The fast Fourier transform algorithm is an efficient method for calculating the discrete Fourier transform, which greatly reduces the amount of calculation and can quickly and accurately obtain the discrete spectrum, so as to perform frequency-domain analysis on the discrete time-domain signal.

[0092] S33. To more intuitively analyze the energy distribution of the signal, the amplitude of the discrete spectrum is normalized, and a standardized power spectral density function is established. The formula for the standardized power spectral density function is as follows:

[0093] P(ω) = |X(ω)| 2 / 2πT;

[0094] where T is the signal observation duration.

[0095] Through the above formula, the amplitude of the frequency-domain signal is normalized, so that the spectra of different signals can be compared on the same scale. The power spectral density function represents the energy distribution of the signal at different frequencies, and through it, it can be clearly seen which frequencies the energy of the signal mainly concentrates on.

[0096] S4. Determine the main frequency of the rigid pipe, the main frequency of the elastic pipe 6, and the main frequency of the flow-induced vibration according to the power spectral density functions of the rigid pipe and the elastic pipe 6, and judge whether the main frequency of the rigid pipe and the main frequency of the flow-induced vibration meet the frequency decoupling condition.

[0097] The frequency decoupling condition is that the main frequency of the rigid pipe is greater than or less than the main frequency of the flow-induced vibration by ±50%.

[0098] The frequency domain characteristic decomposition diagrams of the rigid pipe and the elastic pipe 6 are as Figure 7 shown. By observing the frequency domain characteristic diagrams of the rigid pipe and the elastic pipe 6, it is found that the power spectrum of the rigid pipe forms the main frequency characteristic of the ambient vibration at 6.2 Hz, and the vibration spectrum of the elastic pipe 6 presents a characteristic peak of the flow-induced vibration at 23.6 Hz. The two main frequency components show a significant interval of 17.4 Hz in the frequency domain, meeting the frequency decoupling criterion of the fluid-structure coupling system and verifying the accurate extraction of the characteristic frequency of the flow-induced vibration.

[0099] S5. Perform band-pass filtering on the signals of the acceleration sensor 7 based on the frequency band of the flow-induced vibration, and use the time-domain displacement data of the rigid pipe to compensate for the error of the integral trend term of the acceleration sensor 7.

[0100] Design a band-pass filter, construct a two-channel cascade filtering architecture through the MATLAB platform to achieve the amplitude attenuation of the ambient interference frequency band (4 - 8 Hz), and at the same time retain the integrity of the vibration signals in the characteristic frequency band (20 - 27 Hz). The passband boundaries in the parameter matrix of the band-pass filter are ±50% of the main frequency of the flow-induced vibration, that is, 0.5 times the main frequency of the flow-induced vibration - 1.5 times the main frequency of the flow-induced vibration. During the signal processing, let the acceleration signal pass through this filter, so as to lock the signal processing frequency band within the frequency range of ±50% of the main frequency of the flow-induced vibration, effectively extract the frequency components related to the flow-induced vibration, and provide strong support for subsequent vibration analysis and research.

[0101] The specific method of using the time-domain displacement data of the rigid pipe to compensate for the error of the integral trend term of the acceleration sensor 7 is as follows:

[0102] Align the integral displacement of the acceleration sensor 7 with the time-domain displacement data of the rigid pipe. Integrating the acceleration signal can obtain displacement information, but during the integration process, due to the influence of measurement errors, signal noise and other factors, the integrated displacement data may have a trend term error. To compensate for this error, reference displacement data is introduced, that is, the flow-induced vibration displacement data of the elastic pipe 6 after vector calculation of the motion data of the elastic pipe 6 and the rigid pipe processed by the high-speed camera 5. First, align the time-domain data of the acceleration integral displacement and the reference displacement to ensure the accurate correspondence between the two on the time axis.

[0103] Calculate and eliminate the trend term offset of the integrated displacement of the acceleration zone sensor. After completing the time-domain data alignment, it is necessary to calculate the trend term offset of the integrated displacement. By comparing the acceleration integrated displacement and the reference displacement data, the difference in trend between the integrated displacement and the reference displacement can be found. Over a period of time, the acceleration integrated displacement may show a linear growth or decay trend, while the reference displacement may be relatively stable. This difference between the two is the trend term offset. After calculating the trend term offset, this offset can be subtracted from the acceleration integrated displacement data to eliminate the trend term error. Suppose after calculation, it is found that the trend term offset of the integrated displacement over a period of time is a linear function y = ax + b (where x represents time, and a and b are constants). Then subtracting this function value from the integrated displacement data can make the integrated displacement data closer to the true displacement situation, improve the accuracy of the displacement data, and provide a more reliable basis for subsequent analysis and applications based on the displacement data.

[0104] S6. Perform a second integration on the filtered acceleration sensor 7 signal and output the corrected displacement information.

[0105] Figure 8 For the fluid-induced vibration displacement data of the elastic tube 6 calculated by the corrected acceleration sensor 7 and the results of the fluid-induced vibration displacement data of the elastic tube 6 obtained by using the high-speed camera 5; Figure 9 For the fluid-induced vibration displacement data of the uncorrected elastic tube 6. As Figure 8 、 Figure 9 shown. Tests were carried out in the flow velocity range of 0.5 - 1.8 m / s. The maximum relative error between the two is ≤5%, and the average error is reduced by 62% compared with the traditional acceleration integration method, effectively expanding the applicability of the sensor method under complex working conditions.

[0106] As Figure 2 shown. A measurement system for implementing the above vibration displacement measurement method based on multi-source data fusion includes:

[0107] A water tank 2 for storing fluid.

[0108] A gas compressor 3 for providing a gas source.

[0109] An experimental tube 4 for mixing fluid and gas and measuring vibration displacement. The experimental tube 4 is connected to the water tank 2 through a circulation pipeline, and the gas compressor 3 is connected to the experimental tube 4 through a connecting pipe. A rigid tube and an elastic tube 6 are arranged inside the experimental tube 4. The experimental tube 4 is made of aluminum alloy. The fluid and gas enter through the bottom end of the experimental tube 4, mix inside the experimental tube 4, and then flow out from the top end of the experimental tube 4 and return to the water tank 2. When the mixture of fluid and gas flows inside the experimental tube 4, it causes the fluid-induced vibration of the elastic tube 6.

[0110] A high-speed camera 5 is located on one side of the experimental tube 4 and is used to obtain the motion sequence images of the elastic tube 6 and the rigid tube.

[0111] An acceleration displacement sensor is arranged at the free end of the elastic tube 6 and is triggered synchronously with the high-speed camera 5.

[0112] A data processor is electrically connected to both the high-speed camera 5 and the acceleration displacement sensor. It performs displacement separation and frequency band analysis processing on the motion sequence images and performs integral correction processing on the acceleration displacement data.

[0113] The water tank 2, the gas compressor 3, the experimental tube 4, and the high-speed camera 5 are all fixed on the base 1, and the base 1 is fixed on the ground.

[0114] Both ends of the rigid tube are fixed inside the experimental tube 4. The rigid tube is a solid tube, so that the rigid tube is mainly affected by the vibration of the equipment, and the vibration of the fluid on the rigid tube can be ignored.

[0115] As Figure 3 shown. The elastic tube 6 is a stepped tube. The diameter of one end of the elastic tube 6 is 8 mm - 15 mm, and the diameter of the other end is 22 mm - 28 mm. The smaller diameter section of the elastic tube 6 is fixed inside the experimental tube 4, and the larger diameter section of the elastic tube 6 is a free section. The acceleration displacement sensor is fixedly arranged in a groove 50 mm away from the free end of the elastic tube 6.

[0116] The rigid tube and the elastic tube 6 are made of the same material. The larger diameter end of the elastic tube 6 is a hollow tube with a wall thickness of 1 mm.

[0117] The optical axis of the high-speed camera 5 is located on the central plane of the rigid tube and the elastic tube 6.

[0118] Therefore, by adopting the vibration displacement measurement method and measurement system based on multi-source data fusion of the present invention, the problem that the existing vibration measurement methods cannot effectively unify measurement accuracy and engineering applicability can be solved.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions of the present invention or make equivalent replacements, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A vibration displacement measurement method based on multi-source data fusion, characterized in that, It includes the following steps: S1. Obtain the motion sequence images of the flexible tube and the rigid tube through a high-speed camera, and simultaneously collect the vibration acceleration signals of the flexible tube through an acceleration sensor; S2. Extract the displacement trajectories of the flexible tube and the rigid tube respectively from the motion sequence images, and separate the time history curve of the fluid-induced vibration displacement of the flexible tube through displacement vector operation; S3. Conduct frequency-domain analysis on the displacement trajectory data of the rigid tube and the flexible tube respectively, establish the power spectral density functions of the rigid tube and the flexible tube; determine the frequency bands of the rigid tube and the flexible tube; S4. Determine the main frequency of the rigid tube, the main frequency of the flexible tube and the main frequency of the fluid-induced vibration according to the power spectral density functions of the rigid tube and the flexible tube, and judge whether the main frequency of the rigid tube and the main frequency of the fluid-induced vibration meet the frequency decoupling condition; S5. Perform band-pass filtering on the acceleration sensor signals based on the frequency band of the fluid-induced vibration, and use the time-domain displacement data of the rigid tube to compensate for the error of the integral trend term of the acceleration sensor; S6. Integrate the filtered acceleration sensor signals twice and output the corrected displacement information.

2. The vibration displacement measurement method based on multi-source data fusion according to claim 1, characterized in that The specific content of S2 is as follows: S21. Perform gray conversion and region cropping processing on the original video frames of the motion sequence images; S22. Extract the time-domain displacement trajectory function f1(x, y) of the rigid tube and the time-domain displacement trajectory function f2(x, y) of the flexible tube respectively through motion tracking software; S23. Construct a displacement vector operation model to obtain the time history curve of the fluid-induced vibration displacement trajectory function of the flexible tube and obtain the time history curve of the fluid-induced vibration displacement of the flexible tube; The displacement vector operation model is: f(x, y) = f1(x, y) - f1(x, y); where f(x, y) is the time history curve of the fluid-induced vibration displacement trajectory function of the flexible tube.

3. A vibration displacement measurement method based on multi-source data fusion according to claim 1, characterized in that The specific content of S3 is as follows: S31. Establish a frequency-domain decoupling analysis model, perform continuous Fourier transform on the displacements of the rigid tube and the flexible tube respectively to obtain the frequency-domain expressions; the frequency-domain decoupling analysis model is: where X(ω) is the frequency-domain function, ω is the angular frequency, t is the time variable, j is the imaginary unit, and x(t) is the displacement at time t; S32. Calculate the discrete spectrum using the fast Fourier transform algorithm; Wherein, X[k] is the discrete spectrum, N is the sampling capacity, k is the frequency, n is the number of sampling times, x[n] is the discrete time-domain signal, and the frequency resolution Δf = f s / N, f s is the sampling frequency; S33. Normalize the amplitude of the discrete spectrum and establish a standardized power spectral density function; P(ω) = |X(ω)| 2 / 2πT; where T is the signal observation duration.

4. A vibration displacement measurement method based on multi-source data fusion according to claim 1, characterized in that: In S4, the frequency decoupling condition is that the main frequency of the rigid tube is greater than or less than the main frequency of the fluid-induced vibration ±50%; 5. A vibration displacement measurement method based on multi-source data fusion according to claim 1, characterized in that: In S5, the passband boundary of the band-pass filtering is the main frequency of the fluid-induced vibration ±50%; 6. A vibration displacement measurement method based on multi-source data fusion according to claim 1, characterized in that: In S5, using the time-domain displacement data of the rigid tube to compensate for the error of the integral trend term of the acceleration sensor is specifically: Align the integral displacement of the acceleration sensor with the time-domain displacement data of the rigid tube, and calculate and eliminate the trend term offset of the integral displacement of the acceleration sensor.

7. A measurement system for implementing a vibration displacement measurement method based on multi-source data fusion according to any one of claims 1-6, characterized in that, It includes: A water tank for storing fluid; A gas compressor for providing a gas source; An experimental tube for mixing fluid and gas and measuring vibration displacement. The experimental tube is connected to the water tank through a circulation pipeline, and the gas compressor is connected to the experimental tube through a connecting pipe; a rigid tube and a flexible tube are arranged in the experimental tube; A high-speed camera 5 located on one side of the experimental tube for obtaining the motion sequence images of the flexible tube and the rigid tube; An acceleration displacement sensor is arranged at the free end of the elastic tube and is triggered synchronously with the high-speed camera 5; A data processor is electrically connected to both the high-speed camera 5 and the acceleration displacement sensor, and performs displacement separation, frequency band analysis processing on the motion sequence images and integral correction processing on the acceleration displacement data.

8. A measurement system according to claim 7, characterized in that: Both ends of the rigid tube are fixed inside the experimental tube; the elastic tube is a stepped tube. The smaller-diameter section of the elastic tube is fixed inside the experimental tube, and the larger-diameter section of the elastic tube is the free section.

9. A measurement system according to claim 8, characterized in that: The rigid tube and the elastic tube are made of the same material. The rigid tube is a solid tube, and the elastic tube is a hollow tube.

10. A measurement system according to claim 7, characterized in that: The optical axis of the high-speed camera 5 lies on the central plane of the rigid tube and the elastic tube.

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