CN116299147B - One-dimensional structure internal sound source positioning method based on acoustic coherence technology - Google Patents
One-dimensional structure internal sound source positioning method based on acoustic coherence technology Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 38
- 238000005316 response function Methods 0.000 claims abstract description 35
- 238000001228 spectrum Methods 0.000 claims description 5
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- 238000004364 calculation method Methods 0.000 claims description 2
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- 238000010606 normalization Methods 0.000 claims description 2
- 238000001514 detection method Methods 0.000 abstract description 6
- 230000005284 excitation Effects 0.000 abstract description 6
- 238000005259 measurement Methods 0.000 abstract description 4
- 230000006872 improvement Effects 0.000 description 13
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
- G01S1/72—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using ultrasonic, sonic or infrasonic waves
- G01S1/76—Systems for determining direction or position line
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/18—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using ultrasonic, sonic, or infrasonic waves
- G01S5/20—Position of source determined by a plurality of spaced direction-finders
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/30—Assessment of water resources
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- General Physics & Mathematics (AREA)
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- Radar, Positioning & Navigation (AREA)
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- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Abstract
The invention relates to the field of acoustic detection, in particular to a one-dimensional structure internal sound source positioning method based on acoustic coherence technology. The method mainly comprises the following steps: step 1) excitation is carried out at one end of a one-dimensional structure, and sensor receiving is arranged at the other end of the one-dimensional structure; step 2) acquiring a full-length frequency response function of the component in the scanned frequency band; step 3) exciting the sound source in the component by using signals with the same frequency band, and keeping the position of the receiving sensor unchanged; step 4) obtaining a frequency response function of the receiving point of the component under the excitation of the step 3); step 5) dividing the frequency response function obtained in the step 4) by the frequency response function obtained in the step 2), and performing Fourier transform on the obtained result to obtain the position of the sound source inside the component. The positioning method provided by the invention does not need to carry out multipoint measurement, does not need complex equipment, is simple to operate, has definite results, and is easy to popularize in actual detection.
Description
Technical Field
The invention relates to the field of acoustic detection, in particular to a one-dimensional structure internal sound source positioning method based on acoustic coherence technology.
Background
Localization of targets or sound sources is a frequently encountered need in acoustic detection, and current localization methods mainly include: exciting by adopting pulse waves, and calculating the target position according to the time of the target reflected echo; measuring the sound field in multiple points (multiple probes), and then positioning the sound source by adopting an array signal processing technology; and acquiring position information by adopting an external device such as a laser vibration meter and a mechanical scanning system, and fusing the position information with a detection signal for positioning. The above methods generally require complex devices or cumbersome measurement procedures.
Disclosure of Invention
The invention aims to solve the problems that the prior art needs multipoint measurement or needs complex instruments and complicated signal processing procedures.
In order to achieve the above purpose, the present invention is realized by the following technical scheme.
The invention provides a one-dimensional structure internal sound source positioning method based on acoustic coherence technology, which comprises the following steps:
acquiring a full-length frequency response function at one end of a one-dimensional structure, and acquiring a partial-length frequency response function from a sound source to be positioned to the end;
and carrying out Fourier transform of a wave number domain on the ratio of the partial length frequency response function to the full length frequency response function to obtain the position of the sound source in the one-dimensional structure.
As one of the improvements of the above technical solutions, the method specifically includes the following steps:
step 1) arranging a receiving sensor at one end of a one-dimensional structure;
step 2) exciting an acoustic signal x (t) at the other end of the one-dimensional structure, obtaining a received signal y (t) by a receiving sensor, and obtaining a full length frequency response function FRF based on x (t) and y (t) 0 (ω)；
Step 3) exciting the one-dimensional structure internal sound source to emit an acoustic signal x '(t) with the same frequency band signal as in step 2), obtaining a received signal y' (t) by a receiving sensor, and obtaining a partial length frequency response function FRF based on x '(t) and y' (t) x (ω)；
Step 4) FRF x (omega) and FRF 0 (omega) division to obtain a frequency response curve
And 5) carrying out Fourier transform on the F (omega) wave number domain to obtain the position of the sound source in the one-dimensional structure.
As one of the improvements of the above technical solutions, x (t) in the step 2) and x' (t) in the step 3) are both sweep frequency signals or single frequency signals.
As one of the improvements of the above technical solution, the frequency range of x (t) in the step 2) and x' (t) in the step 3) is not lower than twice the first-order longitudinal resonance frequency of the one-dimensional structure.
As one of the improvements of the above technical scheme, the first-order longitudinal resonance frequency f 1 The calculation formula of (2) is as follows:
wherein c 0 The sound velocity of longitudinal wave in the one-dimensional structure is L, and the length of the one-dimensional structure is L.
As one of the improvements of the above technical solution, the full length frequency response function FRF obtained in the step 2) is 0 The expression (ω) is:
where Y (ω) is the Fourier transform of the received signal Y (t) and X (ω) is the Fourier transform of the transmitted signal X (t).
As one of the improvements of the above technical solution, the partial length frequency response function FRF obtained in the step 3) x The expression (ω) is:
where Y '(ω) is the fourier transform of the received signal Y' (t), and X '(ω) is the fourier transform of the transmitted signal X' (t).
As an improvement of the foregoing technical solution, the step 5) specifically includes:
step 5-1) Using the abscissa of the F (ω) curve as the speed of sound c 0 Normalization, i.e. conversion to the wavenumber domain, yields an F (k) curve, whichIn which the variable k=ω/c 0 ；
And 5-2) carrying out Fourier transform on the F (k) to obtain a signal spectrum, wherein the abscissa corresponding to the signal spectrum is the position of the sound source in the one-dimensional structure.
Compared with the prior art, the invention has the advantages that:
1. the positioning method based on the acoustic coherence technology does not need complex equipment, single-point measurement is simple to operate;
2. the method can directly obtain the target position information, has definite result and is easy to popularize in actual detection.
Drawings
FIG. 1 is a flow chart of the method of the present invention;
FIG. 2 is a typical one-dimensional structure and its internal sound source, where L has a length of 0.3m;
FIG. 3 shows a one-dimensional full length Frequency Response Function (FRF) 0 (ω), solid line), and internal sound source positions of 0.15m (FRF), respectively L/2 (ω), dashed line) and 0.1m (FRF) L/3 (ω), dot-dash line) the right-hand end surface measurement point frequency response function;
FIG. 4 is FRF L/2 (omega) and FRF L/3 (omega) divided by full length frequency response function FRF 0 (ω) results.
Fig. 5 is a result of fourier transform of the curve obtained in fig. 3, and it can be found that the spectral peaks of the curve are at 0.1m and 0.15m on the abscissa, respectively.
Detailed Description
The technical scheme of the invention is described in detail below with reference to the accompanying drawings and examples.
The applicant finds that, for a structure with a length L, the distance between the internal sound source and the left end face is x, if the wave number of the emitted signal is k, for a common one-dimensional solid structure in air, the sound wave in the structure generates total reflection on the left end face and the right end face due to the fact that the difference of acoustic impedances on two sides of a solid-gas interface is large, and after a sound field is stable, the response of the right surface is as follows:
when x=0, i.e., the sound source is located on the left surface, coskx=1, i.e., the 1/ksinkL term in the above equation is the response of the right surface of the workpiece when the sound source is located on the left surface. The method can be obtained through experimental tests, the coskx can be obtained by processing the formula (4), and then the x, namely the internal sound source position, can be obtained by carrying out Fourier transform of the wave number domain on the obtained signal.
Based on the above research, the invention provides a method for positioning a sound source inside a structure by utilizing the acoustic wave coherence principle, as shown in fig. 1, which is a flow chart of the method. The method comprises the following steps:
step 1) exciting an acoustic signal at one end of a structure, and arranging a sensor for receiving at the other end;
step 2) acquiring a full-length frequency response function FRF of the structure in the scanned frequency band 0 (ω)；
Step 3) exciting an internal sound source of the structure by using signals of the same frequency band, wherein the position of a receiving sensor is unchanged;
step 4) acquiring frequency response function FRF of the structure under excitation in step 3) and receiving points x (ω)；
And 5) dividing the frequency response function obtained in the step 4) by the frequency response function obtained in the step 2), and performing Fourier transform on the obtained result to obtain the position of the sound source inside the structure.
As an improvement of the method, in the step 1), the excitation point and the receiving point are respectively located at two end faces of the one-dimensional structure, the excitation signal is x (t), and the receiving signal is y (t).
As an improvement of the above method, the excitation signals of the step 1) and the step 3) are sweep frequency signals or single frequency signals.
As an improvement of the above method, the frequency band of the scanning signal in the step 2) and the step 3) should be not lower than twice the first-order longitudinal resonance frequency of the structure.
As an improvement of the above method, the first-order longitudinal resonance frequency f 1 ：
Wherein c 0 The sound velocity of longitudinal waves in the structure is L, and the length of the structure is one-dimensional.
As an improvement of the above method, the intermediate frequency function FRF (ω) in the steps 2) and 4) is:
where Y (ω) is the Fourier transform of the received signal Y (t) and X (ω) is the Fourier transform of the transmitted signal X (t).
As an improvement of the above method, the specific step of performing fourier transform on the result of dividing the two frequency response functions in step 5) is:
step 5-1) dividing the frequency response function obtained in step 4) by the frequency response function obtained in step 2):
step 5-2) Sound velocity c for abscissa of the curve obtained in step 5-1) 0 Normalized, i.e. converted to the wavenumber domain, an F (k) curve is obtained, where k=ω/c 0 ；
And 5-3) carrying out Fourier transform on the F (k), wherein the abscissa corresponding to the signal spectrum is the position of the internal sound source.
A typical one-dimensional structure is shown in fig. 2, in this example, the structure length is 0.3m and the internal sound source is x from the left end of the structure. Firstly, exciting a sweep frequency signal at the left end, measuring and obtaining a response function (FRF) of the structure at the frequency band at the right end, wherein the sweep frequency range is 1 kHz-100 kHz 0 (ω), solid line); the distance between the internal sound source and the left end is set to be 0.15m (L/2), the sound source is excited to emit a signal, and the signal is received at the right end face to obtain a response function (FRF) within 1 kHz-100 kHz L/2 (ω), dashed line); setting the distance from the inner sound source to the left end to be 0.1m (L/3), and obtaining a response function (FRF) within 1 kHz-100 kHz L/3 (ω), dot-dash lines) as shown in fig. 3.
FRF L/2 (omega) and FRF L/3 (omega) divided by full length frequency response function FRF 0 As shown in fig. 4, the frequency response functions obtained in the above steps are all obtained by taking the amplitude (absolute value) of the signal, and thus the curve obtained in fig. 4 is a full-wave cosine signal.
Fig. 5 shows the fourier transform result of the wave number domain transform of the signal in fig. 4, considering that the frequency of the full wave cosine signal is twice that of the original cosine signal, the wave number domain transform needs to be reduced, i.e. k=ω×2/c 0 . As can be seen from fig. 5, the method can directly obtain the positions of the sound source of 0.15m and 0.1m respectively.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and are not limiting. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present invention, which is intended to be covered by the appended claims.
Claims (7)
1. A one-dimensional structure internal sound source positioning method based on acoustic coherence technology comprises the following steps:
acquiring a full-length frequency response function at one end of a one-dimensional structure, and acquiring a partial-length frequency response function from a sound source to be positioned to the end;
performing fourier transform of the wave number domain on the ratio F (ω) curve of the partial length frequency response function to the full length frequency response function to obtain the position of the sound source inside the one-dimensional structure, including: the abscissa of the F (omega) curve is used as the sound velocity c 0 Normalization, i.e. conversion to the wavenumber domain, yields an F (k) curve, where the variable k=ω/c 0 ；
And F (k) is subjected to Fourier transform to obtain a signal spectrum, and the abscissa corresponding to the signal spectrum is the position of the sound source in the one-dimensional structure.
2. The method for positioning an internal sound source in a one-dimensional structure based on acoustic coherence technology according to claim 1, characterized in that it comprises the following steps:
step 1) arranging a receiving sensor at one end of a one-dimensional structure;
step 2) exciting an acoustic signal x (t) at the other end of the one-dimensional structure, obtaining a received signal y (t) by a receiving sensor, and obtaining a full length frequency response function FRF based on x (t) and y (t) 0 (ω)；
Step 3) exciting the one-dimensional structure internal sound source to emit an acoustic signal x '(t) with the same frequency band signal as in step 2), obtaining a received signal y' (t) by a receiving sensor, and obtaining a partial length frequency response function FRF based on x '(t) and y' (t) x (ω)；
Step 4) FRF x (omega) and FRF 0 (omega) division to obtain a frequency response curve
And 5) carrying out Fourier transform on the F (omega) wave number domain to obtain the position of the sound source in the one-dimensional structure.
3. The method for positioning the internal sound source in the one-dimensional structure based on the acoustic coherence technique according to claim 2, wherein x (t) in the step 2) and x' (t) in the step 3) are both sweep frequency signals or single frequency signals.
4. The method for positioning an internal sound source in a one-dimensional structure based on acoustic coherence technique according to claim 2, wherein the frequency range of x (t) in step 2) and x' (t) in step 3) is not lower than twice the first-order longitudinal resonance frequency of the one-dimensional structure.
5. The method for one-dimensional structure internal sound source localization based on acoustic coherence technique according to claim 4, wherein the first order longitudinal resonance frequency f 1 The calculation formula of (2) is as follows:
wherein c 0 The sound velocity of longitudinal wave in the one-dimensional structure is L, and the length of the one-dimensional structure is L.
6. The method for positioning the internal sound source of the one-dimensional structure based on the acoustic coherence technique according to claim 2, wherein the full-length frequency response function FRF obtained in the step 2) is 0 The expression (ω) is:
where Y (ω) is the Fourier transform of the received signal Y (t) and X (ω) is the Fourier transform of the transmitted signal X (t).
7. The method for positioning internal sound source in one-dimensional structure based on acoustic coherence technique according to claim 2, wherein the partial length frequency response function FRF obtained in step 3) x The expression (ω) is:
where Y '(ω) is the fourier transform of the received signal Y' (t), and X '(ω) is the fourier transform of the transmitted signal X' (t).
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