Planar receiving array with wide-frequency-band working range and underwater acoustic transducer

Abstract

The invention provides a planar receiving array with a wide-frequency-band working range. The planar receiving array comprises a sound absorption baffle, a receiving hydrophone element and a metal bottom plate, the sound absorption baffle is mounted on the metal bottom plate, and a plurality of receiving hydrophone elements arranged in an array are further mounted on the metal bottom plate; the array spacing of the plurality of receiving hydrophone elements is the half-wavelength of the working frequency of the planar receiving array; the receiving hydrophone elements arranged along the width direction of the metal bottom plate are connected in series; and the receiving hydrophone elements arranged along the length direction of the metal bottom plate are connected in parallel. The receiving hydrophone element comprising the spherical transducer is matched with the orthogonally arranged zigzag wedges, so that the working frequency band of the planar receiving array is widened, and the universality of the planar receiving array is improved.

Description

Technical Field

[0001] The present invention relates to the field of underwater acoustic transducers and arrays, and in particular, to a planar receiving array and an underwater acoustic transducer with a wide frequency band working range, and in particular, to a receiving transducer array capable of achieving a large directivity opening angle. Background Art

[0002] Hydroacoustic transducers are basic components that convert electrical energy into acoustic energy to achieve underwater target detection and communication. With the continuous application of new technologies and new materials, the technology of hydroacoustic transducers continues to develop rapidly. Multi-beam bathymetric systems are widely used in the fields of seabed surveying and mapping due to their high precision, high efficiency and full coverage.

[0003] Multi-beam detection is a highly integrated technology of hydroacoustic technology, computer technology, navigation and positioning technology, digital sensor technology, etc. Its main working principle is to transmit and receive sound waves in a wide-angle directional manner through transmitting and receiving transducers, and calculate the spatial position of each beam measurement point through various sensors, so as to obtain strip-type water depth data perpendicular to the heading, which greatly improves the surveying efficiency. In order to achieve full-range scanning of the exploration area, the current mainstream multi-beam bathymetric equipment uses a receiving transducer array with a certain directional beam width. The wide directivity of the receiving transducer array can also reduce the sensitivity reduction caused by the main beam offset during the reception of the beam.

[0004] In the underwater extension of the sonar system, the working principle of the sound-absorbing baffle is to absorb and attenuate the sound waves propagating toward the baffle. Combining the sound-absorbing baffle with the receiving transducer can enhance useful signals (such as improving the sensitivity of the array element), shield harmful signals (such as isolating the radiation noise of the hull) and improve the directivity of the elements on the array.

[0005] At present, most of the planar receiving arrays need to redesign the parameters and structure of the receiving arrays for different working frequency bands, and do not have the versatility within a wide working frequency band. Therefore, how to provide a planar receiving array that can work in a wide working frequency band is an urgent problem to be solved.

[0006] Patent document CNCN200920114824.6 discloses a planar receiving array capable of realizing large-angle beam scanning, which mainly includes an anti-sound baffle, on which are mounted a plurality of groups of hydrophone strips, wherein the hydrophone strips are formed by connecting a plurality of point-element hydrophones, and the anti-sound baffle is composed of an upper and lower cover plate and an intermediate layer. However, since the scheme adopts the scheme of setting an air channel on the baffle, the applicable frequency band is relatively narrow and does not have the versatility within a wide working frequency band. Summary of the invention

[0007] In view of the defects in the prior art, the object of the present invention is to provide a planar receiving array and an underwater acoustic transducer with a wide frequency band operating range.

[0008] According to the present invention, a planar receiving array with a wide frequency band working range includes a sound absorbing baffle, a receiving hydrophone element, and a metal bottom plate;

[0009] The sound absorbing baffle is mounted on a metal bottom plate, and a plurality of receiving hydrophone primitives arranged in an array are also mounted on the metal bottom plate; the array spacing of the plurality of receiving hydrophone primitives is half the wavelength of the working frequency of the plane receiving array;

[0010] The receiving hydrophone elements arranged along the width direction of the metal bottom plate are connected in series with each other;

[0011] The receiving hydrophone elements arranged along the length direction of the metal bottom plate are connected in parallel with each other.

[0012] Preferably, the sound absorbing baffle and the metal bottom plate are both provided with a plurality of openings arranged in an array, and the array spacing of the plurality of openings is half the wavelength of the working frequency of the planar receiving array;

[0013] One end of the receiving hydrophone element passes through the opening in the sound-absorbing baffle, extends to the opening on the metal bottom plate, is connected to the metal bottom plate through the opening on the metal bottom plate, and the other end of the receiving hydrophone element extends to the outside of the sound-absorbing baffle.

[0014] Preferably, the sound absorbing baffle comprises a plurality of sawtooth wedges arranged orthogonally in sequence, each sawtooth wedge comprises a plurality of wedge structures arranged in parallel, and the number of wedge structures in different sawtooth wedges is the same or different.

[0015] Preferably, the receiving hydrophone element comprises a spherical transducer and a connecting rod;

[0016] One end of the connecting rod is mounted on the metal base plate, and the other end is connected to the spherical transducer through a decoupling material.

[0017] Preferably, the spherical transducer comprises a first ceramic hemisphere with a hole in the center and a second ceramic hemisphere of the same size; the first ceramic hemisphere and the second ceramic hemisphere are bonded together, and the centers of the two ceramic hemispheres coincide with each other;

[0018] The decoupling material is connected to the spherical transducer through a small hole on the spherical transducer.

[0019] Preferably, the wide frequency band is 20k-30kHz.

[0020] Preferably, it further comprises a cable, wherein the end of the wire in the cable passes through the connecting rod along the axial direction of the connecting rod and is connected to the spherical transducer.

[0021] Preferably, the length L of the wedge structure meets the following requirements:

[0022] c = λf;

[0023] L = λ / 4 = c / (4f)

[0024] Where c is the speed of sound in the medium, f is the lower limit of the cutoff frequency, and λ is the wavelength.

[0025] Preferably, it also includes a first encapsulation layer and a second encapsulation layer;

[0026] The first potting layer is located above the sound absorbing baffle, and the thickness of the first potting layer just does not exceed the connecting rod and does not touch the spherical transducer;

[0027] The second potting layer is located above the first potting layer and completely covers the spherical transducer.

[0028] According to an underwater acoustic transducer provided by the present invention, the planar receiving array with a wide frequency band working range is adopted, and the number of the planar receiving array with a wide frequency band working range is multiple, and the multiple planar receiving arrays with a wide frequency band working range are arranged in an array.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention adopts a receiving hydrophone element including a spherical transducer in combination with orthogonally arranged sawtooth wedges, so that the working frequency band of the planar receiving array is widened, thereby improving the versatility of the planar receiving array.

[0031] 2. The wedge of the present invention can be formed by mold glue injection, which is convenient for repeated use and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0033] Figure 1 It is a structural schematic diagram of the present invention;

[0034] Figure 2 is a schematic diagram of the structure of the sound absorbing baffle;

[0035] Figure 3 This is a schematic diagram of the structure of the first potting of the present invention;

[0036] Figure 4 is a schematic diagram of the structure of a hydrophone primitive;

[0037] Figure 5 This is a schematic diagram of the structure of the second potting of the present invention;

[0038] Figure 6 This is the relevant test data of the present invention.

[0039] The figure shows:

[0040] DETAILED DESCRIPTION

[0041] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0042] Embodiment 1: Embodiment 1 is the basic embodiment of the present invention.

[0043] like Figure 1-5 As shown, the present invention provides a planar receiving array with a wide frequency band working range, including an acoustic baffle 1, a receiving hydrophone element 2, and a metal base plate 3; the acoustic baffle 1 is mounted on the metal base plate 3. In a preferred embodiment, the metal base plate 3 is an aluminum plate, and the metal base plate 3 is bonded to the acoustic baffle 1. A plurality of receiving hydrophone elements 2 arranged in an array are also mounted on the metal base plate 3; the array spacing of the plurality of receiving hydrophone elements 2 is half the wavelength of the working frequency of the planar receiving array; the receiving hydrophone elements 2 arranged along the width direction of the metal base plate 3 are connected in series with each other; the receiving hydrophone elements 2 arranged along the length direction of the metal base plate 3 are connected in parallel with each other;

[0044] The sound absorbing baffle 1 and the metal base plate 3 are both provided with a plurality of array-arranged openings 11, and the array spacing of the plurality of openings is half the wavelength of the working frequency of the planar receiving array; specifically, one end of the receiving hydrophone element 2 passes through the opening in the sound absorbing baffle 1, extends to the opening on the metal base plate 3, is connected to the metal base plate 3 through the opening on the metal base plate 3, and the other end of the receiving hydrophone element 2 extends to the outside of the sound absorbing baffle 1.

[0045] The sound absorbing baffle 1 is a sound absorbing wedge-type baffle; the sound absorbing baffle 1 comprises a plurality of sawtooth wedges 12 arranged orthogonally in sequence, each sawtooth wedge 12 comprises a plurality of parallel arranged wedge structures 13, and the number of wedge structures 13 in different sawtooth wedges 12 is the same or different. The wedge structures 13 are filled with porous sound absorbing materials, and the wedge structures 13 gradually increase from the top to the bottom, so that a large sound absorbing contact area is met while achieving impedance matching, and the sound absorbing baffle designed with sound absorbing wedges can effectively absorb sound.

[0046] The receiving hydrophone element 2 is a spherical hydrophone. Specifically, the receiving hydrophone element 2 includes a spherical transducer 21 and a connecting rod 22. One end of the connecting rod 22 is mounted on the metal base plate 3, and the other end is connected to the spherical transducer 21 through a decoupling material.

[0047] The spherical transducer 21 includes a first ceramic hemisphere with a hole in the center and a second ceramic hemisphere of the same size; the first ceramic hemisphere and the second ceramic hemisphere are bonded together, and the centers of the two ceramic hemispheres coincide; the connecting rod 22 is connected to the spherical transducer 21 through a small hole on the spherical transducer 21; in order to ensure decoupling and insulation, the decoupling material is plastic. The length of the connecting rod 22 determines the distance from the spherical transducer 21 to the sound absorption baffle 1. The sound absorption baffle has different effects on the directional beam width of the transducer at different distances, and can be optimized according to actual conditions.

[0048] In a preferred embodiment, Figure 1 As shown, the planar receiving array with a wide frequency band working range further includes a support column 4 and a cable 5. The support column 4 is mounted at the bottom end of the metal bottom plate 3 and is threadedly connected to the metal bottom plate 3. The end of the wire in the cable is connected to the spherical transducer 21 along the axial direction of the connecting rod 22, passing through the connecting rod 22. The other end of the wire is connected to an external transmitter.

[0049] In order to ensure the sound absorption effect, the sound-absorbing wedge needs to meet two conditions: the characteristic impedance matches the characteristic impedance of the propagation medium, so that the sound waves can propagate into the material without reflection; the material has a large sound attenuation performance, so that most of the incident sound waves are absorbed. Therefore, the sound-absorbing wedge (wedge structure 13) adopts a structure that gradually increases from top to bottom to increase the contact area between the sound-absorbing wedge and the propagation medium. It is generally believed that when the sound-absorbing material appears at the peak position of the sound wave, that is, 1 / 4 wavelength, the maximum absorption rate will appear. The acoustic characteristics of the sound-absorbing wedge are usually expressed by the sound pressure reflection coefficient. When the reflection coefficient is less than or equal to 0.01, the sound absorption coefficient is ≥0.99, and the corresponding lowest frequency is called the cutoff frequency. The sound absorption characteristics of the sound-absorbing wedge (i.e., the wedge structure 13) are mainly determined by the length and shape of the wedge. The length L of the wedge determines the cutoff frequency. Usually, the wedge length is not less than 1 / 4 wavelength of the corresponding cutoff frequency. The length L of the wedge structure 13 meets the following requirements: c=λf; L=λ / 4=c / (4f), where c is the sound speed in the medium, f is the lower limit of the cutoff frequency, and λ is the wavelength.

[0050] like Figure 3 and Figure 5As shown, the planar receiving array with a wide frequency band working range also includes a first potting layer 6 and a second potting layer 7; the first potting layer 6 is located above the sound absorbing baffle 1, and the thickness of the first potting layer 6 just does not exceed the connecting rod 22 and does not touch the spherical transducer 21; the second potting layer 7 is located above the first potting layer 6, and completely covers the spherical transducer 21. The purpose and manufacturing process of the first potting layer 6 and the second potting layer 7 are as follows: In order to ensure the decoupling and insulation between the array elements and the acoustic performance of the transducer, the transducer array needs to be potted multiple times. First, the transducer array is loaded into a potting mold, and a preferred rubber material is used to pot and form a first potting layer 6, so that the thickness of the first potting layer 6 just does not exceed the connecting rod 22 and does not touch the spherical transducer 21; after the first potting layer 6 is completely cured, the transducer is loaded into a new potting mold again, and the second potting layer 7 is formed by potting with epoxy rubber. Multiple potting can not only ensure the insulation performance of the transducer array and enhance the decoupling between the vibrators, but also reduce the bubbles in the potting layer and improve the performance of the transducer. Finally, polyurethane rubber is used to pot the entire transducer.

[0051] Embodiment 2: Embodiment 2 is a specific embodiment of the present invention.

[0052] This embodiment is a module of the receiving transducer array of the full-sea-depth multi-beam bathymetric system, and its operating frequency band is 20kHz to 30kHz. Figure 1 As shown, in this embodiment, the number of sawtooth wedges 12 is 3, and each sawtooth wedge 12 includes 5 parallel arranged wedge structures 13. 16 receiving hydrophone elements 2 are arranged at equal intervals in the length direction of the sound absorbing baffle 1, and 6 receiving hydrophone elements 2 are arranged at equal intervals in the width direction; the array spacing of the receiving hydrophone elements 2 is arranged according to the half wavelength of the working frequency; the 6 receiving hydrophone elements 2 in the width direction of the sound absorbing baffle 1 are connected in series with each other, and the receiving hydrophone elements 2 in the length direction are connected in parallel with the receiving hydrophone elements 2 in the width direction; the entire array is supported by support columns 4, and the support columns 4 are distributed at the four corners of the array; the connection between the support columns and the metal base plate 3 is through threaded connection; the cable 5 is connected to the receiving hydrophone element 2 through the small hole at the bottom of the metal base plate 3. The support column 4 plays a supporting and positioning role in the transducer potting process, and there are threaded holes in the support column 4 for testing and installing the transducer after potting is completed. Figure 3 and Figure 5 Cable 5 should also be included, but it is omitted in the schematic diagram to highlight the key points.

[0053] The sound absorbing baffle 1 is made of appropriate sound absorbing material, and the metal base plate 3 is also provided with corresponding installation and threading holes. In order to ensure the sound absorbing performance of the sound absorbing wedge, the reliability of the bonding between the sound absorbing baffle and the metal base plate needs to be ensured.

[0054] like Figure 6The following are some test data of the present invention. During the test, the directivity of the transducer was measured at 20, 22, 24, 25, 26, 28, and 30kHz in the 20k-30kHz frequency band, where dark green is 20k, blue is 22k, dark blue is 24k, red is 25k, green is 26k, purple is 28k, and black is 30k. One circle of the coordinate axis treats the transducer as a point source, and the normal of the transducer radiation surface is 0 degrees around it in the 360-degree direction. The negative coordinate axis is the normalized logarithm of the sound pressure value received by the transducer, reflecting the transducer's ability to receive sound pressure in different directions. The negative numbers on the coordinate axis are all decibels. It can be seen that the transducer array can achieve a horizontal directivity beam width greater than 140 degrees in the 20k-30kHz frequency band, which is higher than 130 degrees in the prior art literature, which reflects that the present invention also has the characteristics of large directivity flat angles. At the same time, Figure 6 It is also proved that the working frequency band of the present invention is 20k-30kHz, that is, it has a wider working frequency band.

[0055] The present invention provides a receiving transducer array with a wider frequency band designed by using a sound-absorbing baffle, so as to meet the use of receiving transducer arrays in different frequency bands; by using the present invention, the directional beam width of the transducer can be made wider through the sound-absorbing baffle, so as to better meet the requirements of large-angle beam scanning of the planar array;

[0056] The cutoff frequency of the wedge-type sound-absorbing structure of the present invention is determined by the length of the wedge. Above the cutoff frequency, the sound-absorbing wedge can absorb sound well. Therefore, after the wedge is designed, it can be used in a wide frequency band above the cutoff frequency. The size parameters of the receiving hydrophone base source in the present invention can also be further designed according to needs in combination with the length of the wedge. By replacing the receiving hydrophone, a smaller base array volume can be controlled. The wedge can also be formed by mold injection for easy reuse, saving costs.

[0057] The present invention is composed of a plurality of high-sensitivity spherical hydrophone point sources, and can also utilize an external transmitter to realize circuit combination and phase control between point sources, improve the consistency between array elements, and make the directivity of the transducer array have a wider beam width within a wide frequency range.

[0058] The present invention also provides an underwater acoustic transducer, which adopts the planar receiving array with a wide-band working range, and the number of the planar receiving arrays with a wide-band working range is multiple, and the multiple planar receiving arrays with a wide-band working range are arranged in an array. That is, the planar receiving array with a wide-band working range can be used as a module, and the number of modules can be controlled or changed according to needs. The present invention can also change the directional beam width of the base array and reduce the sidelobe level through a combination of different parameter modules, while achieving a large directional opening angle within a wide frequency. In summary, the present invention adopts a modular design, which can be combined according to actual needs to form different beam widths and have a wide directional beam width within a broadband.

[0059] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0060] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A planar receiving array with a wide frequency band operating range, characterized in that: It comprises a sound absorbing baffle (1), a receiving hydrophone element (2), and a metal bottom plate (3); The sound absorbing baffle (1) is mounted on a metal base plate (3), and a plurality of receiving hydrophone elements (2) arranged in an array are also mounted on the metal base plate (3); the array spacing of the plurality of receiving hydrophone elements (2) is half the wavelength of the operating frequency of the plane receiving array; The receiving hydrophone elements (2) arranged along the width direction of the metal bottom plate (3) are connected in series with each other; The receiving hydrophone elements (2) arranged along the length direction of the metal bottom plate (3) are connected in parallel with each other.

2. The planar receiving array with a wide frequency band operating range according to claim 1, characterized in that: The sound absorbing baffle (1) and the metal bottom plate (3) are both provided with a plurality of openings (11) arranged in an array, and the array spacing of the plurality of openings is half the wavelength of the operating frequency of the planar receiving array; One end of the receiving hydrophone element (2) passes through the opening in the sound absorbing baffle (1) and extends to the opening (11) on the metal base plate (3), and is connected to the metal base plate (3) through the opening (11) on the metal base plate (3), and the other end of the receiving hydrophone element (2) extends to the outside of the sound absorbing baffle (1).

3. The planar receiving array with a wide frequency band operating range according to claim 1, characterized in that: The sound absorbing baffle (1) comprises a plurality of sawtooth wedges (12) arranged orthogonally in sequence, each sawtooth wedge (12) comprises a plurality of wedge structures (13) arranged in parallel, and the number of wedge structures (13) in different sawtooth wedges (12) is the same or different.

4. The planar receiving array with a wide frequency band operating range according to claim 1, characterized in that: The receiving hydrophone element (2) comprises a spherical transducer (21) and a connecting rod (22); One end of the connecting rod (22) is mounted on the metal base plate (3), and the other end is connected to the spherical transducer (21) via a decoupling material.

5. The planar receiving array with a wide frequency band operating range according to claim 1, characterized in that: The spherical transducer (21) comprises a first ceramic hemisphere with a hole in the center and a second ceramic hemisphere of the same size; the first ceramic hemisphere and the second ceramic hemisphere are bonded together, and the centers of the two ceramic hemispheres coincide.

6. The planar receiving array with a wide frequency band operating range according to claim 1, characterized in that: The wide frequency band is 20k-30kHz.

7. The planar receiving array with a wide frequency band operating range according to claim 4, characterized in that: It also comprises a cable (5), wherein the end of the conductor in the cable is connected to the spherical transducer (21) along the axial direction of the connecting rod (22), passes through the connecting rod (22).

8. The planar receiving array with a wide frequency band operating range according to claim 1, characterized in that: The length L of the wedge structure (13) meets the following requirements: c = λf; L = λ / 4 = c / (4f) Where c is the speed of sound in the medium, f is the lower limit of the cutoff frequency, and λ is the wavelength.

9. The planar receiving array with a wide frequency band operating range according to claim 1, characterized in that: It also includes a first encapsulation layer (6) and a second encapsulation layer (7); The first potting layer (6) is located above the sound absorbing baffle (1), and the thickness of the first potting layer (6) just does not exceed the connecting rod (22) and does not touch the spherical transducer (21); The second potting layer (7) is located above the first potting layer (6) and completely covers the spherical transducer (21).

10. An underwater acoustic transducer, characterized in that: A planar receiving array with a wide frequency band working range according to any one of claims 1 to 9 is used, wherein the number of the planar receiving arrays with a wide frequency band working range is multiple, and the multiple planar receiving arrays with a wide frequency band working range are arranged in an array.

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