Eddy current detection system and method

Abstract

The present application discloses a vortex detection system and method, the system includes: a sound wave generating end; a sound wave receiving end; a control device coupled to the sound wave receiving end. The present invention transmits an initial sound wave signal to the area to be measured through the sound wave generating end, and the initial sound wave signal received by the sound wave receiving end is a plurality of measured sound pressure signals generated after passing through the area to be measured. The control device determines whether there is an eddy current in the area to be measured according to the phase difference between the plurality of measured sound pressure signals and the preset sound pressure signal phase difference. Since the navigation of underwater vehicles will inevitably generate eddy currents, and the eddy currents can exist for a long time, therefore, the detection and analysis of eddy currents by the present technical solution not only innovates the detection method of underwater vehicles and reduces the dependence on traditional sonar systems, but also because the eddy currents exist for a long time, the stability of detection is improved, and the accuracy of underwater vehicle track detection results is high.

Description

Technical Field

[0001] The present invention relates to the field of eddy current detection, and in particular to an eddy current detection system and method. Background Art

[0002] In recent years, sonar has been mainly used to detect underwater vehicles, thereby realizing the identification of underwater targets.

[0003] However, the maneuverability and concealment of underwater targets are developing rapidly. By laying sound-absorbing and sound-isolating acoustic covering layers on the surface and selecting low-noise equipment and high-performance vibration isolation components inside, the noise level of underwater vehicles has become lower and lower, resulting in continuous restrictions on sonar detection. The detection process is time-consuming, costly, inefficient, and has considerable uncertainty.

[0004] Therefore, it is necessary to provide a new detection and identification angle based on the unique properties of underwater vehicle navigation. Underwater vehicles generally use propellers as propulsion. During the navigation process, large-scale vortices and internal waves and other eddy flow phenomena will inevitably be formed, leaving corresponding physical field information, collectively referred to as hydrodynamic wakes. Hydrodynamic wakes last for a long time in the ocean and are widely distributed in space. Their vortex flow characteristics have become one of the foundations of target detection and tracking. Based on the above characteristics, using eddy currents as reference parameters for detecting underwater moving target tracks not only reduces dependence on sonar systems, but also improves the stability of detection and the accuracy of detection results. Summary of the invention

[0005] In view of this, it is necessary to provide an eddy current detection system and method, which can detect the track of underwater vehicles by detecting and analyzing eddy currents.

[0006] In order to achieve the above objectives, the present invention provides an eddy current detection system and method, the system comprising:

[0007] The sound wave generating end is used to transmit the initial sound wave signal to the area to be tested;

[0008] The sound wave receiving end is used to receive a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be measured;

[0009] The control device is coupled to the sound wave receiving end and is used to determine whether there is an eddy current in the area to be measured according to the phase difference of the multiple measured sound pressure signals and the preset sound pressure signal phase difference.

[0010] In order to solve the above problems, the present invention also provides an eddy current detection method based on the eddy current detection system described above, comprising:

[0011] The sound wave generating end transmits the initial sound wave signal to the area to be tested;

[0012] The sound wave receiving end receives a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be measured;

[0013] The control device determines whether there is an eddy current in the area to be measured according to the phase difference of the multiple measured sound pressure signals and the preset sound pressure signal phase difference.

[0014] Preferably, the sound wave generating end includes a generating end signal generator, a power amplifier and an underwater acoustic transducer; the sound wave generating end transmits an initial sound wave signal to the area to be measured, including:

[0015] The generating end signal generator generates an electrical signal;

[0016] The power amplifier amplifies the power of the electrical signal to obtain an amplified electrical signal;

[0017] The hydroacoustic transducer converts the amplified electrical signal into an initial sound wave signal and transmits it to the area to be tested.

[0018] Preferably, the sound wave receiving end includes a data acquisition instrument and a plurality of receiving end hydrophones distributed in an array; the sound wave receiving end receives a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be measured, including:

[0019] The multiple receiving-end hydrophones distributed in the array successively receive the multiple measurement sound pressure signals generated after the initial sound wave signal passes through the area to be measured;

[0020] The data acquisition device collects a plurality of measured sound pressure signals and transmits them to the control device.

[0021] Preferably, the control device includes a coherent analyzer; the control device determines whether there is an eddy current in the measured area according to the phase difference of the multiple measured sound pressure signals and the preset sound pressure signal phase difference, including:

[0022] The coherence analyzer determines a plurality of phase differences of the plurality of measured sound pressure signals based on the plurality of measured sound pressure signals;

[0023] The multiple phase differences are compared with the preset sound pressure signal phase difference to determine whether there is an eddy current in the test area.

[0024] Preferably, the coherent analyzer determines a plurality of phase differences of the plurality of measured sound pressure signals according to the plurality of measured sound pressure signals, including:

[0025] The coherent analyzer obtains a plurality of time delays corresponding to the plurality of measured sound pressure signals according to the plurality of measured sound pressure signals;

[0026] According to the multiple time delays, multiple phase differences are determined by utilizing the relationship between the time delay, the phase difference and the underwater sound speed.

[0027] Preferably, determining a preset sound pressure signal phase difference includes:

[0028] The sound wave generating end transmits preset sound wave signals to the eddy flow field without eddy current and the eddy flow field with eddy current respectively;

[0029] The sound wave receiving end receives two groups of measured sound pressure signals generated after the preset sound wave signal passes through the eddy flow field without eddy current and the eddy flow field with eddy current respectively;

[0030] The control device determines a preset sound pressure signal phase difference according to the two groups of measured sound pressure signals.

[0031] Preferably, determining a preset sound pressure signal phase difference according to two sets of measured sound pressure signals includes:

[0032] According to the two groups of measured sound pressure signals, the peak value of each group of measured sound pressure signals and the corresponding time point are obtained;

[0033] According to each group of time points, two groups of time delays are obtained by making corresponding differences;

[0034] According to the two groups of time delays, a preset sound pressure signal phase difference is determined.

[0035] Preferably, the sound wave generating end further includes a plurality of generating end hydrophones distributed in an array, and the sound wave receiving end further includes a plurality of receiving end sound wave generators distributed in an array; and the eddy current detection method further includes:

[0036] A plurality of receiving-end sound wave generators distributed in an array transmit a test sound wave signal to the area to be tested;

[0037] A plurality of hydrophones distributed in an array receive a plurality of test sound pressure signals generated after the test sound wave signal passes through the test area;

[0038] The control device determines whether there is an eddy current in the area to be tested according to the phase difference of the multiple test sound pressure signals and the preset sound pressure signal phase difference.

[0039] Preferably, the parameters of the verification sound wave signal and the initial sound wave signal are the same.

[0040] The beneficial effect of adopting the above technical solution is: the present invention provides an eddy current detection system and method, the system includes: a sound wave generating end; a sound wave receiving end; a control device coupled to the sound wave receiving end. The present invention transmits an initial sound wave signal to the area to be measured through the sound wave generating end, and the sound wave receiving end receives a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be measured. The control device determines whether there is an eddy current in the area to be measured according to the phase difference between the plurality of measured sound pressure signals and the preset sound pressure signal phase difference. Since the navigation of underwater vehicles will inevitably generate eddy currents, and eddy currents can exist for a long time, therefore, by detecting and analyzing eddy currents through the present technical solution, not only the detection method of underwater vehicles is innovated, and the dependence on the sonar system is reduced, but also due to the high stability of eddy currents, the stability of detection is improved, and the accuracy of underwater vehicle track detection results is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic structural diagram of an eddy current detection system according to an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of a flow chart of an embodiment of an eddy current detection method provided by the present invention;

[0043] Figure 3 A schematic diagram of a flow chart of an embodiment of transmitting an initial sound wave signal from a sound wave generating end provided by the present invention;

[0044] Figure 4 A schematic diagram of a flow chart of an embodiment of the present invention for determining whether an eddy current exists in a region to be tested;

[0045] Figure 5 A schematic diagram of a flow chart of an embodiment of obtaining a preset sound pressure signal phase difference provided by the present invention;

[0046] Figure 6 A schematic diagram of the process flow of an embodiment of reverse eddy current detection provided by the present invention. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0048] At present, the detection of underwater vehicle tracks mainly relies on the sonar system. However, in view of the characteristics of sonar, the underwater vehicle has a sound-absorbing and sound-isolating acoustic covering layer laid on the surface, and low-noise equipment and high-performance vibration isolation components are selected inside, making the noise level of the underwater vehicle lower and lower, resulting in continuous restrictions on sonar detection.

[0049] In order to detect the trace of underwater vehicles, this technical solution detects and analyzes the eddy currents that are bound to be generated during the movement of underwater vehicles, thereby realizing the detection of the trace of underwater vehicles. When the sound waves emitted by the detection pass through an eddy current whose characteristic size is much larger than the wavelength, an acoustic scattering phenomenon of the eddy current field will occur, causing the wavefront distortion of the arriving sound wave, that is, the coherence phenomenon, wherein the phase information contained in the coherent wave is closely related to the characteristics of the eddy current. After acquiring and analyzing the characteristics of the acoustic scattering field, the eddy current structure and its dynamic characteristics in the wake can be determined, including the vortex ring radius, distribution, characteristic scale and vorticity, etc., so as to achieve the purpose of detection and identification based on these characteristic values. The present invention provides an eddy current detection system and method, which are described in detail below.

[0050] like Figure 1 As shown, Figure 1This is a schematic diagram of the structure of an eddy current detection system according to an embodiment of the present invention. The eddy current detection system 100 includes:

[0051] The sound wave generating end 101 is used to transmit an initial sound wave signal to the area to be tested;

[0052] The sound wave receiving end 102 is used to receive a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be measured;

[0053] The control device 103 is coupled to the sound wave receiving end 102 and is used to determine whether there is an eddy current in the area to be measured according to the phase difference of the multiple measured sound pressure signals and the preset sound pressure signal phase difference.

[0054] The present invention transmits an initial sound wave signal to the area to be tested through the sound wave generating end 101, and the sound wave receiving end 102 receives a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be tested, and the control device 103 determines whether there is an eddy current in the area to be tested according to the phase difference between the plurality of measured sound pressure signals and the preset sound pressure signal phase difference. Since the navigation of an underwater vehicle will inevitably generate an eddy current, and the eddy current can exist for a long time, after obtaining a plurality of measured sound pressure signals through the technical solution, the eddy current information is inverted, and the eddy current is detected and analyzed to realize the trace detection of the underwater vehicle, which not only innovates the detection method of the underwater vehicle and reduces the dependence on the sonar system, but also realizes the improvement of the detection stability due to the high stability of the eddy current, and the accuracy of the trace detection result of the underwater vehicle is high.

[0055] In order to solve the above problems, the present invention also provides an eddy current detection method based on the eddy current detection system described above, such as Figure 2 As shown, Figure 2 A schematic flow chart of an embodiment of an eddy current detection method provided by the present invention includes:

[0056] Step S11: the sound wave generating end transmits an initial sound wave signal to the area to be tested.

[0057] Step S12: the sound wave receiving end receives a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be measured.

[0058] Step S13: The control device determines whether there is an eddy current in the measured area according to the phase difference of the multiple measured sound pressure signals and the preset sound pressure signal phase difference.

[0059] In the embodiment of the present invention, since the navigation of the underwater vehicle will inevitably generate eddies, and the eddies can exist for a long time, an initial sound wave signal is emitted to the area to be measured through the sound wave generating end; the sound wave receiving end receives a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be measured; the control device obtains the phase difference of the plurality of measured sound pressure signals by analyzing and calculating the plurality of measured sound pressure signals, and compares and determines whether the phase difference of the plurality of measured sound pressure signals is consistent with the preset sound pressure signal phase difference, thereby determining whether there is an eddy current in the area to be measured.

[0060] As a preferred embodiment, in step S11, the sound wave generating end includes a generating end signal generator, a power amplifier and an underwater acoustic transducer. In order to clearly illustrate the process of the sound wave generating end transmitting the initial sound wave signal, as shown in FIG. Figure 3 As shown, Figure 3 The present invention provides a flow chart of an embodiment of a sound wave generating end transmitting an initial sound wave signal. The sound wave generating end transmitting an initial sound wave signal includes:

[0061] Step S111: the generating end signal generator generates an electrical signal.

[0062] Step S112: The power amplifier amplifies the power of the electrical signal to obtain an amplified electrical signal.

[0063] Step S113: The underwater acoustic transducer converts the amplified electrical signal into an initial sound wave signal and transmits it to the area to be tested.

[0064] It can be understood that after the sound wave generating end obtains the instruction to emit the initial sound wave signal, the signal generator at the generating end will generate an electrical signal for emitting the sound wave; in order to increase the power of the electrical signal transmission, the power of the electrical signal is amplified by a power amplifier to ensure that the electrical signal can be accurately transmitted to the underwater acoustic transducer; the underwater acoustic transducer converts the amplified electrical signal into an initial sound wave signal and emits it to the area to be tested.

[0065] In step S112, the electrical signal generated by the generating end signal generator is amplified by a power amplifier, ensuring that the underwater acoustic transducer can receive accurate electrical signals, and when the underwater acoustic transducer converts the electrical signal into an initial sound wave signal, it can ensure that the power of the initial sound wave signal meets the usage requirements.

[0066] In a specific embodiment, the types of power amplifiers include but are not limited to Class A, Class B, Class AB, Class D and Class T.

[0067] In step S113, the initial sound wave signal includes but is not limited to a triangular wave, a sawtooth wave, and a rectangular wave. A waveform with specific waveform parameters may also be set, that is, a waveform with specific waveform parameters is obtained by designing parameters such as the amplitude, leading edge and rise time, trailing edge and fall time, width, interval, period and frequency of the initial sound wave signal; so as to more accurately capture, analyze and judge the underwater signal.

[0068] In step S113, the initial sound wave signal can be set to a fixed frequency mode or a sweep frequency mode, with a lower limit of not less than 1kHz and an upper limit of not more than 10kHz. When the frequency is too low, the wavelength of the sound wave is long, which will bypass the eddy current field and cause missed judgment; when the frequency is too high, the wavelength of the sound wave is short, and the error in phase analysis is large; the upper limit of the frequency is also related to the attenuation of the sound wave in the water. The lower the frequency, the smaller the absorption and attenuation of the seawater to the sound wave, so the frequency of the sound wave signal should not be too high.

[0069] As a preferred embodiment, in step S12, the sound wave receiving end includes a data acquisition instrument and a plurality of receiving end hydrophones distributed in an array.

[0070] Among them, after the initial sound wave signal passes through the area to be measured, since multiple receiving-end hydrophones are distributed in an array, the multiple measured sound pressure signals obtained are distributed according to certain characteristics, which is convenient for subsequent data analysis; the data acquisition instrument transmits the collected multiple measured sound pressure signals to the control device.

[0071] Furthermore, in order to ensure a certain target intensity and a sufficient sound wave propagation distance, the distance between the signal generator at the generating end and the hydrophone at the receiving end can also be adjusted to change the signal receiving time interval. That is, when the distance between the signal generator at the generating end and the hydrophone at the receiving end is reduced, the signal receiving time interval is shortened, and the characteristics of the time domain signal occupied by the time delay caused by the eddy current field are obvious.

[0072] In a specific embodiment, both the underwater acoustic transducer and the sound wave receiving end are selected to be transducers with high sensitivity, strong anti-interference and anti-signal crosstalk capabilities, and low-frequency vectors with a large dynamic range.

[0073] In a specific embodiment, in order to ensure the accuracy of the multiple measured sound pressure signals, the error of synchronous sampling of the multiple receiving-end hydrophones is no more than 100 ns.

[0074] As a preferred embodiment, in step S13, the control device includes a coherent analyzer. In order to clearly explain the process of determining whether there is an eddy current in the test area according to multiple measured sound pressure signals, as shown in FIG. Figure 4 As shown, Figure 4 A schematic diagram of a flow chart of an embodiment of determining whether an eddy current exists in a region to be tested provided by the present invention, wherein determining whether an eddy current exists in a region to be tested includes:

[0075] Step S131: The coherent analyzer obtains a plurality of time delays corresponding to the plurality of measured sound pressure signals according to the plurality of measured sound pressure signals.

[0076] Step S132: Determine multiple phase differences based on multiple time delays using the relationship between time delay, phase difference and underwater sound speed.

[0077] Step S133: compare the multiple phase differences with the preset sound pressure signal phase difference to determine whether there is an eddy current in the test area.

[0078] It can be understood that after the coherent analyzer obtains multiple measured sound pressure signals, since the positions of the hydrophones at each receiving end are different, multiple measured sound pressure signals can be compared with each other to obtain multiple time delays; further, since the product of the time delay and the underwater sound speed is equal to the phase difference, that is, the phase difference between the multiple measured sound pressure signals can be determined by obtaining multiple time delays; finally, there is a certain quantitative relationship between the phase differences of the sound wave signals caused by the influence of eddy currents, therefore, by comparing the multiple obtained phase differences with the preset sound pressure signal phase difference, it can be determined whether there are eddy currents in the test area.

[0079] That is to say, in this embodiment, multiple time delays are obtained by comparing multiple measured sound pressure signals, and then phase differences of multiple measured sound pressure signals are obtained based on the multiple time delays. Finally, by comparing the multiple phase differences with the preset sound pressure signal phase difference, it is determined whether there is an eddy current in the measured area.

[0080] As a preferred embodiment, in step S13, after obtaining the phase differences of multiple measured sound pressure signals, it is also necessary to obtain the preset sound pressure signal phase difference before making a judgment. In order to clearly explain the process of obtaining the preset sound pressure signal phase difference, as shown in FIG. Figure 5 As shown, Figure 5 The present invention provides a flow chart of an embodiment of obtaining a preset sound pressure signal phase difference. The process of obtaining the preset sound pressure signal phase difference includes:

[0081] Step S21: the sound wave generating end transmits initial sound wave signals to the vortex-free flow field and the vortex-containing flow field respectively.

[0082] Step S22: the sound wave receiving end receives two groups of measured sound pressure signals generated after the initial sound wave signal passes through the eddy flow field without eddy current and the eddy flow field with eddy current respectively.

[0083] Step S23: the control device determines a preset sound pressure signal phase difference according to the two groups of measured sound pressure signals.

[0084] It can be understood that when an initial sound wave signal is emitted to an eddy flow field known to have vortices, the multiple sound pressure signals with vortices received by the sound wave receiving end must have time delays, and by calculating each time delay, multiple phase differences with vortices corresponding to the multiple sound pressure signals with vortices are obtained; further, in order to avoid the influence of other external factors such as the environment, in this embodiment, an initial sound wave signal is emitted to an eddy flow field known to have no vortices, and the sound wave receiving end receives multiple sound pressure signals without vortices, and then analyzes and determines whether the multiple sound pressure signals without vortices have no vortex delays. If so, multiple phase differences without vortex are calculated, and the values ​​of the multiple phase differences with vortex are subtracted from the multiple phase differences without vortex, so as to determine the preset sound pressure signal phase difference; if not, the multiple phase differences with vortex are the preset sound pressure signal phase difference.

[0085] Furthermore, the coherent analysis system in the control device calculates eddy current acoustic scattering based on the eddy current model, and the eddy current velocity distribution is as follows:

[0086]

[0087] Among them, r represents the distance from a certain point in space to the center of the vortex core, a is the radius of the vortex core, Γ=2.8πacMa represents the vortex circulation, c is the speed of sound in water, the speed of sound in water and the speed of sound profile vary with different underwater environments, and Ma is the Mach number.

[0088] According to the axisymmetric phase calculation algorithm, the vortex flow field is between the acoustic signal transmitting end and the receiving end of the underwater acoustic transducer, and there are vortices with a certain vortex ring volume and radius. The steady-state vortex field can be regarded as a stable axisymmetric motion medium, and the vortex field is divided into n radial ranges with a radius of r. i (i∈[1,n]) of small concentric rings. The first ring r1 is defined as being located at the edge of the eddy current field. Because it is a stable eddy current, the eddy current field velocity in each ring can be approximately considered to be a constant u i .

[0089] The coherent analysis system has a built-in eddy current field calculation database with and without eddy currents, and saves the propagation time t of the acoustic signal under various eddy current parameters. 0 The acoustic signal propagation time t is measured in the presence of an eddy current field. The difference in acoustic signals from different hydrophones in the array is the time delay δt, and the product of the time delay and the speed of sound is the phase difference.

[0090] The phase difference generated by the sound wave after passing through the eddy current field can be defined as:

[0091]

[0092] Among them, ω is the rotation circle frequency, the upper limit of the integral represents the transmitting end, the lower limit of the integral represents the receiving end, c is the speed of sound in water, u is the tangential velocity of the eddy field, and n is the number of small concentric rings.

[0093] Expand the above formula in series and ignore the high-order small quantities to get:

[0094]

[0095] In the first ring r1, the tangential velocity of the eddy current field is u1, and the velocity component on the y-axis is u1cosθ. The phase difference of the acoustic signal passing through the first ring of the eddy current is:

[0096]

[0097] Similarly, in the second ring r2, the tangential velocity of the eddy current field is u2, the velocity component on the y-axis is u2cosθ, and the phase difference of the acoustic signal passing through the ring r2 is:

[0098]

[0099] Here, the sound signal passes through the two rings r1 and r2, and the total phase difference of the received sound signal is:

[0100]

[0101] The phase difference of the sound wave passing through each ring is independent of each other, so the above steps can be repeated until the sound signal passes through the central ring of the vortex core r n , the general expression of phase difference can be summarized as:

[0102]

[0103] Δφ i =E ij u j .

[0104] In a specific embodiment, the data of the preset sound pressure signal phase difference is obtained based on the parameter changes of the propeller blade geometry, different propeller operating conditions, and underwater environment. In order to improve the accuracy and speed of phase difference matching, it is necessary to regularly update the database of the preset sound pressure signal phase difference.

[0105] Further, in order to improve the accuracy of the eddy current detection result, the sound wave generating end further includes a plurality of array-distributed generating end hydrophones, the sound wave receiving end further includes a plurality of array-distributed receiving end sound wave generators, and the eddy current detection method further includes reverse detection of eddy currents, such as Figure 6 As shown, Figure 6 The present invention provides a schematic flow diagram of an embodiment of a reverse eddy current detection method, wherein the reverse eddy current detection method includes:

[0106] Step S31: multiple receiving-end sound wave generators distributed in an array transmit inspection sound wave signals to the area to be tested.

[0107] Step S32: multiple hydrophones distributed in an array receive multiple test sound pressure signals generated after the test sound wave signal passes through the test area.

[0108] Step S33: The control device determines whether there is an eddy current in the test area according to the phase difference of the multiple test sound pressure signals and the preset sound pressure signal phase difference.

[0109] It can be understood that this method adds an eddy current detection on the basis of the eddy current detection method described above. By exchanging the positions of the sound wave generating end and the sound wave receiving end, the phase difference of multiple test sound pressure signals is obtained, and then the phase difference of the multiple test sound pressure signals is compared with the preset sound pressure signal phase difference. The judgment method and judgment criteria are the same as above and will not be repeated here.

[0110] Through the above method, the accuracy of eddy current field recognition and judgment is improved. Assuming that the probability of successful detection is P, similarly, because the same detection device and method are used, the probability of successful reverse detection is P. The probability of success after detection and direction detection conforms to the generalized addition formula, that is, the probability of success after reverse detection is 2P+P 2 , and because the probability of successful detection is always greater than 0 and less than 1, the reverse detection process can greatly increase the probability of successful detection.

[0111] Furthermore, the control device also includes an alarm, which issues an alarm prompt after detecting the eddy current.

[0112] In the above manner, after obtaining multiple measured sound pressure signals generated by the initial sound wave signal passing through the test area, the coherence analysis method is used to calculate multiple phase differences corresponding to the multiple measured sound pressure signals, and compared with the preset sound pressure signal phase difference to determine whether there is an eddy current. Furthermore, in order to improve the accuracy of eddy current detection, a reverse detection method is also proposed.

[0113] The eddy current is detected by the technical solution provided in this application, so as to determine whether there is a trace of an underwater vehicle. Since the eddy current is an inevitable product of the movement of underwater vehicles and exists for a long time, the dependence on the sonar system is reduced in the field of underwater vehicle trace detection.

[0114] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An eddy current detection method, characterized in that: include: The sound wave generating end transmits the initial sound wave signal to the area to be tested; The sound wave receiving end receives a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be measured; The control device determines whether there is an eddy current in the test area according to the phase difference of the multiple measured sound pressure signals and the preset sound pressure signal phase difference; The control device includes a coherent analyzer; The control device determines whether there is an eddy current in the test area according to the phase difference of the multiple measured sound pressure signals and the preset sound pressure signal phase difference, including: The coherence analyzer determines a plurality of phase differences of the plurality of measured sound pressure signals based on the plurality of measured sound pressure signals; Comparing the multiple phase differences with the preset sound pressure signal phase difference to determine whether an eddy current exists in the test area; The coherent analyzer determines a plurality of phase differences of the plurality of measured sound pressure signals according to the plurality of measured sound pressure signals, including: The coherent analyzer obtains a plurality of time delays corresponding to the plurality of measured sound pressure signals according to the plurality of measured sound pressure signals; Determine the multiple phase differences according to the multiple time delays and using the relationship between the time delay, the phase difference and the underwater sound speed; Determining the preset sound pressure signal phase difference includes: The sound wave generating end transmits preset sound wave signals to the eddy flow field without eddy current and the eddy flow field with eddy current respectively; The sound wave receiving end respectively receives two groups of measurement sound pressure signals generated after the preset sound wave signal passes through the eddy flow field without eddy current and the eddy flow field with eddy current; The control device determines the preset sound pressure signal phase difference according to the two groups of measured sound pressure signals; Determining the preset sound pressure signal phase difference according to the two groups of measured sound pressure signals includes: According to the two groups of measured sound pressure signals, the peak value of each group of measured sound pressure signals and the corresponding time point are obtained; According to each group of time points, two groups of time delays are obtained by correspondingly making differences; The preset sound pressure signal phase difference is determined according to the two groups of time delays.

2. The eddy current detection method according to claim 1, characterized in that: The sound wave generating end includes a generating end signal generator, a power amplifier and an underwater acoustic transducer; the sound wave generating end transmits an initial sound wave signal to the area to be measured, including: The generating end signal generator generates an electrical signal; The power amplifier performs power amplification on the electrical signal to obtain an amplified electrical signal; The hydroacoustic transducer converts the amplified electrical signal into the initial sound wave signal and transmits it to the area to be tested.

3. The eddy current detection method according to claim 1, characterized in that: The acoustic wave receiving end includes a data acquisition instrument and a plurality of receiving end hydrophones distributed in an array; The sound wave receiving end receives a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be measured, including: The multiple receiving-end hydrophones distributed in the array successively receive multiple measurement sound pressure signals generated after the initial sound wave signal passes through the area to be measured; The data acquisition instrument acquires the plurality of measured sound pressure signals and transmits them to the control device.

4. The eddy current detection method according to claim 1, characterized in that: The sound wave generating end further includes a plurality of generating end hydrophones distributed in an array, and the sound wave receiving end further includes a plurality of receiving end sound wave generators distributed in an array; the eddy current detection method further includes: The plurality of receiving-end sound wave generators distributed in the array transmit inspection sound wave signals to the area to be tested; The plurality of generating end hydrophones distributed in the array receive a plurality of inspection sound pressure signals generated after the inspection sound wave signal passes through the area to be tested; The control device determines whether there is an eddy current in the test area according to the phase difference between the multiple inspection sound pressure signals and the preset sound pressure signal phase difference.

5. The eddy current detection method according to claim 4, characterized in that: The parameters of the inspection sound wave signal and the initial sound wave signal are the same.

6. An eddy current detection system, characterized in that: Used to perform the eddy current detection method according to any one of claims 1 to 5, the system comprises: The sound wave generating end is used to transmit the initial sound wave signal to the area to be tested; A sound wave receiving end, used for receiving a plurality of measured sound pressure signals generated after the initial sound wave signal passes through the area to be measured; The control device is coupled to the sound wave receiving end and is used to determine whether there is an eddy current in the area to be measured according to the phase difference of the multiple measured sound pressure signals and the preset sound pressure signal phase difference.

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