Displacement information acquisition method and device of multi-point displacement meter

Abstract

The invention provides a displacement information acquisition method and device of a multi-point displacement meter, and relates to the technical field of coal mine safety. The method comprises the following steps: transmitting a pulse excitation signal through a waveguide wire of a multi-point displacement meter, and sampling sound wave signals generated during elastic deformation of the waveguide wire on different base points to obtain original sound wave signals; eMD is carried out on the original sound wave signal to obtain N IMF components; filtering the N IMF components, and obtaining a reduced sound wave signal based on the filtered IMF components; performing cross-correlation calculation on the reduced sound wave signal and the pulse excitation signal to obtain a cross-correlation result corresponding to the base point, and determining position information of the base point according to the cross-correlation result corresponding to the base point; and determining the displacement information of the base point according to the position information of the base point determined at least twice. The displacement monitoring accuracy can be improved, the separation condition of the surrounding rock can be accurately monitored, measures can be taken in time, roof caving is avoided, and safety accidents are reduced.

Description

Technical Field

[0001] This application relates to the technical field of coal mine safety, and particularly to a method and device for obtaining displacement information of a multi-point displacement meter. Background Art

[0002] The surrounding rock of a roadway refers to the rock or soil structure surrounding the roadway during the excavation process of an underground roadway. Since underground excavation will damage the surrounding rock, which will in turn lead to the separation of the surrounding rock, and the separation of the surrounding rock is often a precursor to roof caving. In the coal mine underground operation scenario, roof caving may cause safety accidents. Summary of the Invention

[0003] The purpose of this application is to solve at least one of the technical problems in the related art to a certain extent.

[0004] To this end, the first purpose of this application is to propose a method for obtaining displacement information of a multi-point displacement meter, which can monitor the displacement of the surrounding rock, and then determine the separation of the surrounding rock, so as to take timely support measures and effectively avoid the occurrence of roof caving accidents and reduce safety accidents such as miner casualties.

[0005] The second purpose of this application is to propose a device for obtaining displacement information of a multi-point displacement meter.

[0006] The third purpose of this application is to propose an electronic device.

[0007] The fourth purpose of this application is to propose a computer-readable storage medium.

[0008] The fifth purpose of this application is to propose a computer program product.

[0009] To achieve the above object, the first aspect embodiment of this application proposes a method for obtaining displacement information of a multi-point displacement meter, including:

[0010] Propagate a pulse excitation signal through the waveguide wire of the multi-point displacement meter, and sample the acoustic signals generated during the elastic deformation of the waveguide wire at different base points to obtain the original acoustic signals;

[0011] Perform empirical mode decomposition (EMD) on the original acoustic signals to obtain N intrinsic mode function (IMF) components;

[0012] Filter the N IMF components, and obtain the restored acoustic signals based on the filtered IMF components;

[0013] Perform cross-correlation calculation on the restored acoustic signals and the pulse excitation signal to obtain the cross-correlation results corresponding to the base points, and determine the position information of the base points according to the cross-correlation results corresponding to the base points;

[0014] Determine the displacement information of the base point according to the position information of the base point determined at least twice.

[0015] To achieve the above object, an embodiment of the second aspect of the present application provides a displacement information acquisition device for a multi-point displacement meter, including:

[0016] A signal sampling module, configured to transmit a pulse excitation signal through the waveguide wire of the multi-point displacement meter, and sample the acoustic wave signals generated when the waveguide wire elastically deforms at different base points to obtain original acoustic wave signals;

[0017] A modal decomposition module, configured to perform EMD decomposition on the original acoustic wave signals to obtain N IMF components;

[0018] A signal restoration module, configured to filter the N IMF components, and obtain restored acoustic wave signals based on the filtered IMF components;

[0019] A position determination module, configured to perform cross-correlation calculation on the restored acoustic wave signals and the pulse excitation signals to obtain cross-correlation results corresponding to the base points, and determine the position information of the base points according to the cross-correlation results corresponding to the base points;

[0020] A displacement determination module, configured to determine the displacement information of the base point according to the position information of the base point determined at least twice.

[0021] To achieve the above object, an embodiment of the third aspect of the present application provides an electronic device, including: a processor; and a memory communicatively connected to the processor; the memory stores computer execution instructions; the processor executes the computer execution instructions stored in the memory, so that the processor can execute the displacement information acquisition method of the multi-point displacement meter described in the first aspect embodiment above.

[0022] To achieve the above object, an embodiment of the fourth aspect of the present application provides a computer-readable storage medium, on which a computer program is stored, and the computer instructions are used to make the computer execute the displacement information acquisition method of the multi-point displacement meter described in the above embodiment of one aspect.

[0023] To achieve the above object, an embodiment of the fifth aspect of the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, it implements the displacement information acquisition method of the multi-point displacement meter described in the above embodiment of one aspect.

[0024] The method and device for obtaining displacement information of a multi-point displacement meter provided by this application decompose and filter the original acoustic wave signal using the EMD algorithm, and restore the signal based on the filtered IMF components, making the restored acoustic wave signal close to the true original acoustic wave signal. Moreover, it can provide an accurate data source for subsequent cross-correlation calculations, which is beneficial to improving the accuracy of displacement acquisition. Further, the cross-correlation calculation is performed using the pulse excitation signal and the restored acoustic wave signal, and the position information of the base point is determined based on the cross-correlation result, and then the displacement information of the base point is determined, which can effectively reduce the displacement error, improve the monitoring accuracy of the displacement, and can accurately monitor the separation situation of the surrounding rock, so as to take timely support and other measures to effectively avoid the occurrence of roof caving accidents and reduce safety accidents such as miner casualties.

[0025] Additional aspects and advantages of this application will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of this application will become apparent and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0027] Figure 1 is a schematic flow chart of a method for obtaining displacement information of a multi-point displacement meter provided by an embodiment of this application;

[0028] Figure 2 is a schematic diagram of the original acoustic wave signal provided by an embodiment of this application;

[0029] Figure 3 is a schematic flow chart of another method for obtaining displacement information of a multi-point displacement meter provided by an embodiment of this application;

[0030] Figure 4 is a schematic flow chart of a method for obtaining displacement information of a multi-point displacement meter provided by an embodiment of this application;

[0031] Figure 5 is a schematic diagram of the amplitudes of two measurements provided by an embodiment of this application;

[0032] Figure 6 is a schematic diagram of the IMF components provided by an embodiment of this application;

[0033] Figure 7 is a schematic diagram of the cross-correlation result provided by an embodiment of this application;

[0034] Figure 8 is a schematic diagram of the position measurement results of different base points by using the threshold judgment strategy for multiple measurements;

[0035] Figure 9Schematic diagram of the position measurement results of multiple measurements at different base points in the embodiments of the present application;

[0036] Figure 10 Schematic structural diagram of a displacement information acquisition device for a multi-point displacement meter provided in the embodiments of the present application. Detailed implementation manners

[0037] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, but should not be construed as limiting the present application.

[0038] A method and device for acquiring displacement information of a multi-point displacement meter provided in the embodiments of the present application will be explained below in conjunction with the accompanying drawings for the method and device for acquiring displacement information of the multi-point displacement meter.

[0039] Figure 1 Schematic flow diagram of a method for acquiring displacement information based on a multi-point displacement meter provided in the embodiments of the present application. As Figure 1 shown, the method for acquiring displacement information based on the multi-point displacement meter may include but is not limited to the following steps:

[0040] S101, Propagate a pulse excitation signal through the waveguide wire of the multi-point displacement meter, and sample the acoustic signals generated when the waveguide wire elastically deforms at different base points to obtain the original acoustic signals.

[0041] In some embodiments, the multi-point displacement meter emits a pulse excitation signal, which propagates on the waveguide wire. The waveguide wire can pass through different base points of the multi-point displacement meter. A permanent magnet is arranged near each base point. When the pulse excitation signal encounters the axial magnetic field applied by the permanent magnet near the waveguide wire, the changing magnetic field generated by the pulse excitation signal interacts with the constant magnetic field, which will cause the waveguide wire to twist at the position of the axial magnetic field, resulting in the waveguide wire elastically deforming in the form of mechanical pulses. The wave generated by the elastic deformation propagates bidirectionally along the waveguide at the speed of sound and is finally picked up by the sampling chip of the multi-point displacement meter. Optionally, the sampling chip of the multi-point displacement meter can be a pickup coil.

[0042] In some embodiments, the maximum sampling frequency of analog-to-digital (AD) sampling that the sampling chip of the multi-point displacement meter can perform can be determined, and the sampling frequency of the sampling chip can be set based on the maximum sampling frequency. That is to say, the sampling frequency of the sampling chip can be configured to be less than or equal to the maximum sampling frequency.

[0043] In some embodiments, the distance between the farthest base point of the multi-point displacement gauge and the processing chip is determined, and based on the distance and the transmission speed of the acoustic wave signal generated by elastic deformation, the transmission time for the acoustic wave signal generated by elastic deformation at the farthest base point to reach the sampling chip is determined. Further, based on this transmission time, the sampling time interval of the sampling chip is determined. For example, the sampling time interval can be set to 1.05 to 1.1 times this transmission time.

[0044] In some embodiments, the waveguide wire can be excited to undergo elastic deformation by a pulse excitation signal, and acoustic wave signals will be reflected at each base point position of the multi-point displacement gauge. The pulse excitation signal and the acoustic wave signals reflected at each base point position can be collected by the sampling chip of the multi-point displacement gauge.

[0045] Exemplarily, the multi-point displacement gauge can be a multi-point displacement gauge including 20 base points. The original acoustic wave signals collected by the sampling chip of the multi-point displacement gauge at least include the pulse excitation signal and the acoustic wave signals reflected at 20 base point positions. As Figure 2 shown, the original acoustic wave signals at least include the peak of the excitation signal and the peaks of the acoustic wave signals reflected at 20 base points.

[0046] S102. Perform empirical mode decomposition (EMD) on the original acoustic wave signals to obtain N intrinsic mode function (IMF) components.

[0047] In some embodiments, when the multi-point displacement gauge includes 20 base points, the original acoustic wave signals can be expressed by the following formula (1):

[0048] x = [x(1), x(2), x(3), x(4), x(5), …, X(21)] (1)

[0049] In some instances, the following steps 1 to 4 can be used to perform empirical mode decomposition (EMD) on the original acoustic wave signals to obtain N intrinsic mode function (IMF) components.

[0050] Step 1. Search for local maximum points and local minimum points in the original acoustic wave signals, and based on the local maximum points and local minimum points, construct the upper envelope X max (T) and the lower envelope X min (T) of the original acoustic wave signals.

[0051] Step 2. Calculate the mean value of the upper envelope X max (t) and the lower envelope X min (t), and construct the mean envelope of the original acoustic wave signals based on this mean value.

[0052] In some embodiments, the mean envelope can be determined using the following formula (2):

[0053]

[0054] where m1(t) represents the mean envelope.

[0055] Step 3: Subtract the mean envelope from the original acoustic wave signal to obtain the intermediate signal d1(t).

[0056] Step 4: Determine whether the intermediate signal d1(t) meets the screening conditions for IMF components. In response to the intermediate signal d1(t) meeting the screening conditions for IMF components, determine that the intermediate signal d1(t) is an IMF component.

[0057] In response to the intermediate signal d1(t) not meeting the screening conditions for IMF components, use d1(t) as the new original acoustic wave signal and repeat Steps 1 to 4 until the IMF conditions are met.

[0058] In some embodiments, the screening conditions for IMF components include:

[0059] Throughout the entire data range, the number of local extreme points and zero-crossing points must be equal, or the difference in the number is at most 1;

[0060] At any given moment, the average of the envelopes of local maxima (upper envelope) and local minima (lower envelope) must be zero.

[0061] In some embodiments, the sifting threshold (SD) value of the intermediate signal can be calculated. In response to the SD value being less than the set threshold value, determine that the intermediate signal has converged, stop the iteration, and obtain the first-order mode component c1(t), which is the first IMF component. Optionally, the range of the set threshold value can be (0.2 - 0.3).

[0062] In some embodiments, the SD value is determined using the following formula (3):

[0063]

[0064] where d k-1 (t) represents the intermediate signal of the (k - 1)th iteration; d k (t) represents the intermediate signal of the kth iteration; T represents the total length of the original acoustic wave signal.

[0065] In some embodiments, the difference between the original acoustic wave signal x and c1(t) is calculated to obtain the first-order residual signal r1(t). Further, r1(t) is used to replace the original acoustic wave signal x for at least one round of processing in steps 1 to 4 to obtain the second-order modal component c2(t), which is also the second IMF component.

[0066] It can be understood that after repeating n times, the nth-order modal function c n (t) and the final residual signal r n (t) that meet the requirements can be obtained.

[0067] In some embodiments, after the original acoustic wave signal x is processed by EMD decomposition, it can be expressed by the following formula (4):

[0068]

[0069] S103. Filter the N IMF components and obtain the restored acoustic wave signal based on the filtered IMF components.

[0070] In some embodiments, according to the set filtering strategy, the N IMF components can be filtered to obtain the filtered IMF components. Further, the filtered IMF components are superimposed to obtain the restored acoustic wave signal. For example, the IMF components can be filtered based on parameters such as frequency, mean, and variance.

[0071] S104. Calculate the cross-correlation between the restored acoustic wave signal and the pulse excitation signal to obtain the cross-correlation result corresponding to the base point.

[0072] S105. Determine the position information of the base point according to the cross-correlation result corresponding to the base point.

[0073] In some embodiments, the pulse excitation signal u0 used by the multi-point displacement gauge is determined. Further, the cross-correlation between the pulse excitation signal u0 and the restored acoustic wave signal is calculated to obtain the cross-correlation result corresponding to each base point.

[0074] In some embodiments, a sliding window can be set. The width and step size of the sliding window can be set according to the time interval between the peaks of two base points. Based on the sliding window, a band of the restored acoustic wave signal is intercepted. It can be understood that each time the sliding window slides, a band corresponding to a base point can be intercepted.

[0075] Further, the cross-correlation between the band corresponding to the base point and the pulse excitation signal u0 is calculated to obtain the cross-correlation result corresponding to the base point.

[0076] In some embodiments, the maximum amplitude corresponding to the base point is determined from the cross-correlation results corresponding to the base point, and the moment corresponding to the maximum amplitude is determined. Further, based on the moment corresponding to the maximum amplitude and the longitudinal wave velocity of the acoustic wave signal in the waveguide wire, the position information of the base point is determined.

[0077] S106. Determine the displacement information of the base point according to the position information of the base point determined at least twice.

[0078] In some embodiments, for the same base point, the position change amount between the position information of two adjacent times can be calculated, and based on the calculated position change amount, the displacement information of the base point is determined.

[0079] Optionally, the average value of multiple calculated position change amounts is obtained, and the average value is determined as the displacement information of the base point.

[0080] Optionally, the maximum value of multiple calculated position change amounts is obtained, and the maximum value is determined as the displacement information of the base point.

[0081] The method for obtaining the displacement information of the multi-point displacement meter provided by the embodiments of the present application decomposes the collected original acoustic wave signal by using the EMD algorithm, and further restores the signal based on the decomposed IMF components. Since frequency deviation often occurs during the generation and propagation of the acoustic wave of the multi-point displacement meter, the collected original acoustic wave signal is significantly non-linear. By processing the original acoustic wave signal with the EMD algorithm, the frequency characteristics of the acoustic wave signal of the multi-point displacement meter can be combined, so that the restored acoustic wave signal is close to the real original acoustic wave signal, and an accurate data source can be provided for subsequent cross-correlation calculation, which is beneficial to improving the accuracy of displacement acquisition.

[0082] Further, the fixed pulse excitation signal is used to perform cross-correlation calculation with the restored acoustic wave signal, and then the position information of the base point can be determined based on the cross-correlation results, and then the displacement information of the base point can be determined, which can effectively reduce the displacement error, improve the monitoring accuracy of the displacement, and can accurately monitor the separation condition of the surrounding rock, so as to take timely support and other measures, effectively avoid the occurrence of roof caving accidents, and reduce safety accidents such as miner casualties.

[0083] Figure 3 It is a schematic flow chart of a method for obtaining the displacement information of a multi-point displacement meter provided by the embodiments of the present application. As Figure 3 shown, the method for obtaining the displacement information based on the multi-point displacement meter may include but is not limited to the following steps:

[0084] S301. Propagate the pulse excitation signal through the waveguide wire of the multi-point displacement meter, and sample the acoustic wave signals generated when the waveguide wire elastically deforms at different base points to obtain the original acoustic wave signal.

[0085] For a detailed description of step S301, please refer to the possible implementation methods of the relevant steps in each embodiment of the present application, and the steps are not repeated here.

[0086] S302, performing EMD on the original sound wave signal to obtain N IMF components.

[0087] For a detailed description of step S302, please refer to the possible implementation methods of the relevant steps in each embodiment of the present application, and the steps are not repeated here.

[0088] S303: Identify a noise IMF component from the N IMF components.

[0089] In some embodiments, a target residual signal corresponding to an Nth IMF component among N IMF components is determined, and further, a spectrum analysis is performed on the N IMF components and the target residual signal to identify a noise IMF component from the N IMF components.

[0090] In some embodiments, a target residual signal corresponding to the Nth IMF component among the N IMF components is determined. Further, spectrum analysis is performed on the N IMF components and the target residual signal to obtain respective spectrums. Noise identification is performed on the N IMF components according to their respective spectrums and the excitation frequency of the multi-point displacement meter to determine the noise IMF component.

[0091] In some embodiments, for each spectrum, the location of the maximum value is determined from the spectrum, and the frequency corresponding to the location of the maximum value is determined, and the frequency corresponding to the location of the maximum value is compared with the excitation frequency to obtain the frequency offset. In response to the frequency offset being greater than a set frequency offset threshold, it is determined that the IMF component corresponding to the spectrum is a noise IMF component.

[0092] In some embodiments, the amplitude corresponding to the position where the excitation frequency is located is determined from the spectrum, and in response to the amplitude corresponding to the position where the excitation frequency is located being less than a set amplitude threshold, the IMF component corresponding to the spectrum is determined to be a noise IMF component.

[0093] S304, removing the noise IMF component from the N IMF components to obtain the filtered IMF component, and superimposing the filtered IMF component to obtain a restored sound wave signal.

[0094] S305, performing cross-correlation calculation on the restored sound wave signal and the pulse excitation signal to obtain a cross-correlation result corresponding to a base point.

[0095] In some embodiments, the restored sound wave signal can be intercepted to obtain sub-restored sound wave signals corresponding to different base points. For each base point, the sub-restored sound wave signal and the pulse excitation signal are determined to perform cross-correlation calculation to obtain the cross-correlation result corresponding to the base point.

[0096] In some embodiments, the peak of the restored acoustic wave signal can be identified, and the restored acoustic wave signal can be intercepted based on the position where the peak is located, where different peaks correspond to different base points. Optionally, a set time length is intercepted to the left and right with the position where the peak is located as the center, and the sub-restored acoustic wave signal corresponding to the base point is obtained.

[0097] In some embodiments, when the multi-point displacement meter includes 20 base points, the restored acoustic wave signal can be represented by the following formula (5):

[0098] x f =[x f (1), x f (2), x f (3), x f (4), x f (5), …, x f (21)](5)

[0099] where k = 1, 2, 3, ……, 21;

[0100] x f (1) represents the sub-restored acoustic wave signal corresponding to the pulse excitation signal, x f (2) represents the sub-restored acoustic wave signal corresponding to the first base point, x f (3) represents the sub-restored acoustic wave signal corresponding to the second base point, ……, and so on, x f (k) represents the sub-restored acoustic wave signal corresponding to the (k - 1)-th base point.

[0101] Further, the following formula (6) is used to perform cross-correlation calculation on the pulse excitation signal u0 and the sub-restored acoustic wave signal x f (k):

[0102]

[0103] S306. Determine the position information of the base point according to the cross-correlation result corresponding to the base point.

[0104] It can be understood that the cross-correlation result includes amplitudes at different time delays, and the amplitude represents the similarity degree of the two signals at the time delay. The larger the amplitude of the cross-correlation, the higher the matching degree of the two signals at the corresponding time delay.

[0105] In some embodiments, according to the cross-correlation result corresponding to the base point, the maximum amplitude corresponding to the base point and the time delay corresponding to the maximum amplitude are determined. It should be noted that the maximum amplitude in the cross-correlation result represents the optimal matching position when the two signals are aligned, and the time delay corresponding to the maximum amplitude represents the time difference between the pulse excitation signal u0 and x f (k) at the base point.

[0106] Further, according to the time delay corresponding to the maximum amplitude and the longitudinal wave velocity of the acoustic wave signal in the waveguide wire, the position information of the base point is determined. That is, after obtaining the time delay corresponding to each base point, the time delay and the longitudinal wave velocity of the acoustic wave signal in the waveguide wire can be multiplied to obtain the position information of the base point. It can be understood that the pulse excitation signal u0 can be a reference signal, and then the position information of the base point can be determined according to the time delay and the longitudinal wave velocity.

[0107] In some embodiments, different base points are sorted according to the layout positions from near to far to obtain a base point sequence. For the base point i + 1 in the base point sequence, according to the time delay corresponding to the maximum amplitude of the base point i + 1 and the time delay corresponding to the maximum amplitude of the base point i, the time interval between the base point i + 1 and the base point i is determined, where 1 ≤ i ≤ M, and M is the number of base points of the multi-point displacement meter. Further, according to the time interval and the longitudinal wave velocity of the acoustic wave signal in the waveguide wire, the distance between the base point i + 1 and the base point i is obtained.

[0108] Exemplarily, when the multi-point displacement meter includes 20 base points, the time delay corresponding to the maximum amplitude of the base point can be determined according to the cross-correlation result of the base points. Among them, the 21 time delays corresponding to the maximum amplitudes obtained after cross-correlation calculation can be respectively marked as τ1, τ2, τ3, …, τ 21 。

[0109] Further, for the first base point, the time interval τ2 - τ1 between the first base point and the pulse excitation signal emission point can be obtained, and according to the time interval τ2 - τ1 and the longitudinal beam, the distance between the first base point and the pulse excitation signal emission point is determined. Further, starting from the second base point, the time intervals with the previous base point can be calculated, which are τ3 - τ2, τ4 - τ3, …, τ 21 -τ 20 。According to the time interval τ i+1 -τ i and the longitudinal beam, the distance between the base point i + 1 and the base point i is determined.

[0110] S307. Determine the displacement information of the base point according to the position information of the base point determined at least twice.

[0111] For the specific introduction of step S307, reference can be made to the possible implementation manners of the relevant steps in the embodiments of the present application, and the steps are not repeated here.

[0112] In the embodiments of the present application, the EMD algorithm is used to decompose the original acoustic wave signal, and the spectral analysis of the decomposed IMF components is carried out. The spectral characteristics of each modal component are compared with the excitation frequency, and the modes with a large difference in frequency components from the original excitation frequency are removed according to the frequency difference, and the IMF components that can reflect the characteristics of the original acoustic wave signal are retained. Further, the original acoustic wave signal is restored based on the IMF components. Since frequency deviation occurs during the generation and propagation of the acoustic wave of the multi-point displacement meter, the collected acoustic wave signal is significantly non-linear. However, when filtering the IMF components, the frequency characteristics of the acoustic wave signal of the multi-point displacement meter are combined, so that the retained IMF components better meet the restoration requirements.

[0113] Further, the cross-correlation calculation is carried out between the fixed pulse excitation signal and the restored acoustic wave signal, and then the position information of the base point can be determined based on the cross-correlation result, and then the displacement information of the base point can be determined, which can effectively reduce the error of the displacement, improve the monitoring accuracy of the displacement, and can realize the accurate monitoring of the separation condition of the surrounding rock, so as to take timely support and other measures, effectively avoid the occurrence of roof caving accidents, and reduce safety accidents such as miner casualties.

[0114] Figure 4 It is a schematic flow chart of a method for obtaining the monitoring result of a multi-point displacement meter provided by the embodiment of the present application, as Figure 4 shown. The method for obtaining the monitoring result of the multi-point displacement meter may include but is not limited to the following steps:

[0115] S401, Propagate the pulse excitation signal through the waveguide wire of the multi-point displacement meter, and sample the acoustic wave signals generated when the waveguide wire elastically deforms at different base points to obtain the original acoustic wave signal.

[0116] S402, Perform EMD on the original acoustic wave signal to obtain N IMF components.

[0117] S403, Filter the N IMF components, and obtain the restored acoustic wave signal based on the filtered IMF components.

[0118] S404, Perform cross-correlation calculation on the restored acoustic wave signal and the pulse excitation signal to obtain the cross-correlation result corresponding to the base point.

[0119] S405, Determine the position information of the base point according to the cross-correlation result corresponding to the base point.

[0120] S406, Determine the displacement information of the base point according to the position information of the base point determined at least twice.

[0121] For the specific introduction of steps S401 to S406, reference can be made to the possible implementation manners of the embodiments in the present application, and the steps are not repeated here.

[0122] S407. Determine whether there is a risk in the surrounding rock according to the displacement information of the reference point.

[0123] In response to the displacement information of the reference point satisfying the risk condition, it can be determined that there is a risk in the surrounding rock.

[0124] In response to the displacement information of the reference point not satisfying the risk condition, it can be determined that there is no risk in the surrounding rock.

[0125] In some embodiments, a displacement threshold is preset. In response to the displacement information of the reference point being greater than the displacement threshold, it is determined that the displacement information of the reference point satisfies the risk condition; in response to the displacement information of the reference point being less than or equal to the displacement threshold, it is determined that the displacement information of the reference point does not satisfy the risk condition.

[0126] In some embodiments, when it is determined that there is a risk in the surrounding rock, the risk level can be further determined based on the range where the displacement information is located. It can be understood that the greater the displacement, the greater the risk level.

[0127] In some embodiments, when it is determined that there is a risk in the surrounding rock, a warning can be issued. Optionally, corresponding emergency measures can be given in combination with the risk level. For example, support and reinforcement can be carried out, etc.

[0128] The method for obtaining the displacement information of the multi-point displacement meter provided by the embodiment of the present application decomposes the collected original acoustic wave signal by using the EMD algorithm, and further restores the signal based on the decomposed IMF components. Since frequency deviation often occurs during the generation and propagation of the acoustic wave of the multi-point displacement meter, the collected original acoustic wave signal is significantly non-linear. By processing the original acoustic wave signal with the EMD algorithm, the frequency characteristics of the acoustic wave signal of the multi-point displacement meter can be combined, so that the restored acoustic wave signal is close to the real original acoustic wave signal, and it can provide an accurate data source for the subsequent cross-correlation calculation, which is beneficial to improving the accuracy of displacement acquisition.

[0129] Furthermore, the fixed pulse excitation signal is used to perform cross-correlation calculation with the restored acoustic wave signal, and then the position information of the reference point can be determined based on the cross-correlation result, and then the displacement information of the reference point can be determined, which can effectively reduce the displacement error, improve the monitoring accuracy of the displacement, and can accurately monitor the separation condition of the surrounding rock, so as to take timely measures such as support, effectively avoid the occurrence of roof caving accidents, and reduce safety accidents such as miner casualties.

[0130] As Figure 2 shown, the original acoustic wave signal collected by the multi-point displacement meter includes 21 peaks. The first peak is the peak generated by the pulse excitation signal, and the following 20 peaks are the peaks of the acoustic wave signals reflected at 20 reference points measured. By magnifying some of the peaks, it can be found that when measuring A1 and A2 twice, due to the limited sampling frequency, there is a relatively large difference in amplitude, as Figure 5As shown, the amplitude at the same sampling point A1 is 2.06, and the amplitude at A2 is 2.26. When calculating the position of the multi-point displacement gauge, if the threshold judgment strategy is adopted, misjudgment problems will occur. In this application, the acoustic wave signals reflected by each base point are decomposed by EMD, and the IMF components as shown in Figure 6 can be obtained. From top to bottom, they are IMF1 to IMF6 respectively. After removing the components with a large difference in main frequency from the excitation frequency, the original acoustic wave signal can be restored based on the remaining IMF components. By performing cross-correlation calculation on the pulse excitation signal and the restored acoustic wave signal, the cross-correlation result diagram as shown in Figure 7 can be obtained. From Figure 7 , the positions of the peaks extracted according to the cross-correlation results are all 3.72 μs. Figure 8 is a schematic diagram of the position measurement results of 20 base points with 40 measurements using the threshold judgment strategy. Figure 9 are the position measurement results of 20 base points with 40 measurements using the method provided in this application. From Figure 8 and Figure 9 , it can be seen that there are a large number of errors of 1 to 2 pulse periods in the base point positions determined by the threshold judgment strategy, which is very unstable. However, when using the method provided in this application, the base point position measurement results are consistent in 40 measurements, and the stability is greatly improved.

[0131] To implement the above method for obtaining displacement information of the multi-point displacement gauge, the embodiments of the present disclosure also provide a device for obtaining displacement information of the multi-point displacement gauge. As shown in Figure 10 , the device 100 for obtaining displacement information of the multi-point displacement gauge includes: a signal sampling module 11, a modal decomposition module 12, a signal restoration module 13, a position determination module 14, and a displacement determination module 15.

[0132] The signal sampling module 11 is configured to transmit a pulse excitation signal through the waveguide wire of the multi-point displacement gauge and sample the acoustic wave signals generated when the waveguide wire elastically deforms at different base points to obtain the original acoustic wave signal.

[0133] The modal decomposition module 12 is configured to perform EMD decomposition on the original acoustic wave signal to obtain N IMF components.

[0134] The signal restoration module 13 is configured to filter the N IMF components and obtain a restored acoustic wave signal based on the filtered IMF components.

[0135] The position determination module 14 is configured to perform cross-correlation calculation on the restored acoustic wave signal and the pulse excitation signal to obtain the cross-correlation result corresponding to the base point, and determine the position information of the base point according to the cross-correlation result corresponding to the base point.

[0136] The displacement determination module 15 is configured to determine the displacement information of the base point according to the position information of the base point determined at least twice.

[0137] In some embodiments, the signal restoration module 13 is further configured to:

[0138] Identify the noise IMF components from the N IMF components;

[0139] Remove the noise IMF components from the N IMF components to obtain the filtered IMF components;

[0140] Superimpose the filtered IMF components to obtain the restored acoustic wave signal.

[0141] In some embodiments, the mode decomposition module 12 is further configured to:

[0142] Determine the target residual signal corresponding to the Nth IMF component among the N IMF components;

[0143] Perform spectrum analysis on the N IMF components and the target residual signal to identify the noise IMF components from the N IMF components.

[0144] In some embodiments, the signal restoration module 13 is further configured to:

[0145] Perform spectrum analysis on the N IMF components and the target residual signal to obtain their respective spectra;

[0146] Determine the excitation frequency of the pulse excitation signal;

[0147] According to their respective spectra and the excitation frequency, perform noise identification on the N IMF components to determine the noise IMF components.

[0148] In some embodiments, the signal restoration module 13 is further configured to:

[0149] For each of the spectra, determine the maximum value from the spectrum;

[0150] Determine the frequency corresponding to the maximum value;

[0151] Compare the frequency corresponding to the maximum value with the excitation frequency to obtain the frequency offset;

[0152] In response to the frequency offset being greater than the set frequency offset threshold, determine that the IMF component to which the spectrum belongs is the noise IMF component.

[0153] In some embodiments, the signal restoration module 13 is further configured to:

[0154] Determine the amplitude corresponding to the excitation frequency in the spectrum;

[0155] In response to the amplitude corresponding to the excitation frequency being less than a set amplitude threshold, determine that the IMF component to which the spectrum belongs is the noise IMF component.

[0156] In some embodiments, the position determination module 14 is further configured to:

[0157] Intercept the restored acoustic wave signal to obtain sub-restored acoustic wave signals corresponding to different base points;

[0158] For each base point, determine the cross-correlation calculation between the sub-restored acoustic wave signal and the pulse excitation signal to obtain the cross-correlation result corresponding to the base point.

[0159] In some embodiments, the position determination module 14 is further configured to:

[0160] Determine the maximum amplitude from the cross-correlation results corresponding to the base points;

[0161] Determine the time delay corresponding to the maximum amplitude;

[0162] According to the time delay corresponding to the maximum amplitude and the longitudinal wave velocity of the acoustic wave signal in the waveguide wire, determine the position information of the base point.

[0163] In some embodiments, the position determination module 14 is further configured to:

[0164] After determining the time delay corresponding to the maximum amplitude, sort the different base points in ascending order of their layout positions to obtain a base point sequence;

[0165] For the base point i + 1 in the base point sequence, determine the time interval between the base point i + 1 and the base point i according to the time delay corresponding to the maximum amplitude of the base point i + 1 and the time delay corresponding to the maximum amplitude of the base point i, where 1 ≤ i ≤ M and M is the number of base points of the multi-point displacement meter;

[0166] According to the time interval and the longitudinal wave velocity, obtain the distance between the base point i + 1 and the base point i.

[0167] Since the device provided in the embodiments of the present disclosure corresponds to the methods provided in the above several embodiments, the implementation manners of the methods are also applicable to the device provided in this embodiment and will not be described in detail in this embodiment.

[0168] In the above embodiments provided by the present application, the methods and devices provided by the embodiments of the present application are introduced. To implement each function in the methods provided by the above embodiments of the present application, an electronic device may include a hardware structure and software modules, and implement the above functions in the form of a hardware structure, software modules, or a combination of a hardware structure and software modules. A certain function among the above functions may be executed in the form of a hardware structure, software modules, or a combination of a hardware structure and software modules.

[0169] To implement the above embodiments, the present application also provides an electronic device, including: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the methods provided in the foregoing embodiments.

[0170] To implement the above embodiments, the present application also provides a computer-readable storage medium storing computer-executable instructions, and the computer-executable instructions are used to implement the methods provided in the foregoing embodiments when executed by a processor.

[0171] To implement the above embodiments, the present application also provides a computer program product including a computer program, and the computer program implements the methods provided in the foregoing embodiments when executed by a processor.

[0172] The collection, storage, use, processing, transmission, provision, and application of the user's personal information involved in the present application all comply with the provisions of relevant laws and regulations and do not violate public order and good customs.

[0173] It should be noted that personal information from users should be collected for legal and reasonable purposes and not shared or sold outside of these legal uses. In addition, such collection / sharing should be carried out after obtaining the informed consent of the user, including but not limited to notifying the user to read the user agreement / user notice and signing an agreement / authorization including authorizing relevant user information before the user uses the function. In addition, any necessary steps should be taken to protect and safeguard access to such personal information data and ensure that others with access to personal information data comply with their privacy policies and procedures.

[0174] The present application anticipates providing embodiments that allow users to selectively block the use or access of personal information data. That is, the present application anticipates providing hardware and / or software to prevent or block access to such personal information data. Once personal information data is no longer needed, the risk can be minimized by restricting data collection and deleting the data. In addition, when applicable, personal identifiers are removed from such personal information to protect the privacy of the user.

[0175] In the descriptions of the foregoing embodiments, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0176] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0177] Any process or method description in a flowchart or described otherwise herein can be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a customized logical function or process, and the scope of the preferred embodiments of the present application includes additional implementations, where the functions may be executed in a substantially simultaneous manner or in a reverse order according to the functions involved, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0178] The logic and / or steps represented in the flowchart or otherwise described herein can, for example, be considered as a definable sequence list of executable instructions for implementing logical functions, which can be embodied specifically in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in conjunction with these instruction execution systems, apparatuses, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection portion (electronic device) having one or more wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or otherwise processing as appropriate, and then stored in a computer memory.

[0179] It should be understood that various parts of the present application can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), and the like.

[0180] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the method of implementing the above embodiments can be completed by a program instructing relevant hardware, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0181] In addition, each functional unit in various embodiments of the present application may be integrated into one processing module, may exist physically alone for each unit, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0182] The above-mentioned storage medium may be a read-only memory, a magnetic disk, an optical disc, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A method for obtaining displacement information of a multi-point displacement meter, characterized in that, The method includes: Propagating a pulse excitation signal through the waveguide wires of a multi-point displacement meter, and sampling the acoustic signals generated during the elastic deformation of the waveguide wires at different base points to obtain the original acoustic signals; Performing empirical mode decomposition (EMD) on the original acoustic signals to obtain N intrinsic mode function (IMF) components; Filtering the N IMF components and obtaining a restored acoustic signal based on the filtered IMF components; Performing cross-correlation calculation on the restored acoustic signal and the pulse excitation signal to obtain the cross-correlation results corresponding to the base points, and determining the position information of the base points according to the cross-correlation results corresponding to the base points; Determining the displacement information of the base points according to the position information of the base points determined at least twice.

2. The method according to claim 1, wherein The filtering the N IMF components and obtaining a restored acoustic signal based on the filtered IMF components includes: Identifying noise IMF components from the N IMF components; Removing the noise IMF components from the N IMF components to obtain filtered IMF components; Superposing the filtered IMF components to obtain the restored acoustic signal.

3. The method according to claim 2, wherein The identifying noise IMF components from the N IMF components includes: Determining a target residual signal corresponding to the Nth IMF component among the N IMF components; Performing spectral analysis on the N IMF components and the target residual signal to identify noise IMF components from the N IMF components.

4. The method according to claim 3, wherein The performing spectral analysis on the N IMF components and the target residual signal to identify noise IMF components from the N IMF components includes: Performing spectral analysis on the N IMF components and the target residual signal to obtain their respective spectra; Determining the excitation frequency of the pulse excitation signal; Performing noise identification on the N IMF components according to their respective spectra and the excitation frequency to determine the noise IMF components.

5. The method according to claim 3, wherein The performing noise identification on the N IMF components according to their respective spectra and the excitation frequency to determine the noise IMF components includes: For each of the spectra, determining the maximum value from the spectrum; Determining the frequency corresponding to the maximum value; Comparing the frequency corresponding to the maximum value with the excitation frequency to obtain a frequency offset; In response to the frequency offset being greater than a set frequency offset threshold, determining the IMF component to which the spectrum belongs as the noise IMF component.

6. The method according to claim 3, characterized in that The performing noise identification on the N IMF components according to their respective spectra and the excitation frequency to determine the noise IMF components includes: Determining the amplitude corresponding to the excitation frequency in the spectrum; In response to the amplitude corresponding to the excitation frequency being less than a set amplitude threshold, determining the IMF component to which the spectrum belongs as the noise IMF component.

7. The method according to any one of claims 1-6, characterized in that, The performing cross-correlation calculation on the restored acoustic signal and the pulse excitation signal to obtain the cross-correlation results corresponding to the base points includes: Intercepting the restored acoustic signal to obtain sub-restored acoustic signals corresponding to different base points; For each base point, determining cross-correlation calculation between the sub-restored acoustic signal and the pulse excitation signal to obtain the cross-correlation results corresponding to the base point.

8. The method according to any one of claims 1-6, characterized in that Determining the displacement information of the base point according to the corresponding cross-correlation result includes: Determining the maximum amplitude from the cross-correlation result corresponding to the base point; Determining the time delay corresponding to the maximum amplitude; Determining the position information of the base point according to the time delay corresponding to the maximum amplitude and the longitudinal wave velocity of the acoustic wave signal in the waveguide wire.

9. The method according to claim 8, wherein After determining the time delay corresponding to the maximum amplitude, it includes: Sorting the different base points from near to far according to the layout position to obtain a base point sequence; For the base point i + 1 in the base point sequence, determining the time interval between the base point i + 1 and the base point i according to the time delay corresponding to the maximum amplitude of the base point i + 1 and the time delay corresponding to the maximum amplitude of the base point i, where 1 ≤ i ≤ M, and M is the number of base points of the multi-point displacement meter; Obtaining the distance between the base point i + 1 and the base point i according to the time interval and the longitudinal wave velocity.

10. A displacement information acquisition device based on a multi-point displacement meter, characterized in that, The method includes: A signal sampling module, configured to transmit a pulse excitation signal through the waveguide wire of the multi-point displacement meter and sample the acoustic wave signals generated when the waveguide wire elastically deforms at different base points to obtain the original acoustic wave signals; A modal decomposition module, configured to perform EMD decomposition on the original acoustic wave signals to obtain N IMF components; A signal restoration module, configured to filter the N IMF components and obtain a restored acoustic wave signal based on the filtered IMF components; A position determination module, configured to perform cross-correlation calculation on the restored acoustic wave signal and the pulse excitation signal to obtain the cross-correlation result corresponding to the base point, and determine the position information of the base point according to the cross-correlation result corresponding to the base point; A displacement determination module, configured to determine the displacement information of the base point according to the position information of the base point determined at least twice.

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