An underwater acoustic receiving device imitating the finless porpoise

Abstract

The present invention discloses an underwater acoustic receiving device imitating the finless porpoise. It includes: a V-shaped skeleton; first flexible members are fixedly arranged on the outer sides of the two bifurcated ends of the V-shaped skeleton; second flexible members are fixedly arranged on the inner sides of the two bifurcated ends of the V-shaped skeleton, and hydrophones are embedded in the second flexible members; the two hydrophones are arranged in parallel with each other. Based on the research idea of bionics, the designed underwater acoustic receiving device imitating the finless porpoise can enhance the reception of broadband sound waves and form a reception directivity in the wide frequency band. Compared with the prior art, the beneficial effects of the present invention are as follows: Based on the working principle of the sound receiving system of the finless porpoise, the present invention constructs an underwater acoustic receiving device imitating the finless porpoise. By combining and designing the bionic structure, the present invention enhances the reception of wide-frequency sound waves. In addition to the characteristics of simple structure and easy implementation, the present invention also has the advantages of enhancing wide-band and directional sound reception.

Description

Technical Field

[0001] The present invention relates to the technical field of bionic underwater acoustic listening, and in particular to an underwater acoustic receiving device imitating the finless porpoise. Background Art

[0002] Compared with any other form of energy, sound waves have greater propagation advantages in water. Therefore, sound waves are an ideal carrier for long-distance underwater detection and communication. In underwater acoustic applications, the reception of sound waves is a very important link. An excellent underwater acoustic receiver can effectively improve the distance and reliability of underwater acoustic detection and communication. Generally speaking, the bandwidth of a receiver determines the amount of spectral information it can receive. Therefore, many underwater acoustic applications require the underwater acoustic receiver to have as wide a working frequency band as possible. Although the resonant mode of a sound receiver can provide high reception sensitivity, the resonant response is usually narrowband. In order to obtain a flat broadband response, traditional underwater acoustic receivers usually need to operate in a range below their resonant frequency. However, the sensitivity in the non-resonant frequency range is much lower than that near the resonant frequency, which is not conducive to the detection of weak signals. Therefore, new design ideas for underwater acoustic receivers are needed to solve this problem. Summary of the Invention

[0003] In order to cope with the complex and changeable underwater environment, finless porpoises have evolved an excellent biological sonar system, which includes an excellent underwater acoustic receiving system. The underwater acoustic receiving system of the finless porpoise can be regarded as a broadband acoustic impedance matcher, which can not only effectively promote the transmission of acoustic energy, but also enhance the reception of broadband sound waves. In view of this, the purpose of the present invention is to propose an underwater acoustic receiving device imitating the finless porpoise. Referring to the organizational structure characteristics of the finless porpoise's acoustic receiving system, bionic combination design is carried out to enhance the transmission and reception of broadband sound waves. In addition to the characteristics of simple structure and easy implementation, the present invention also has the advantages of enhancing broadband and directional acoustic reception.

[0004] According to one aspect of the present invention, there is provided an underwater acoustic receiving device imitating the finless porpoise, comprising: a V-shaped skeleton; a first flexible member is fixedly provided on the outer sides of the two bifurcated ends of the V-shaped skeleton; a second flexible member is fixedly provided on the inner sides of the two bifurcated ends of the V-shaped skeleton, and a hydrophone is embedded in the second flexible member; the two hydrophones are arranged in parallel with each other.

[0005] In the above technical solution, the overall structure is symmetrically distributed on the left and right, forming a "V" shape. The V-shaped skeleton imitates the jaw of the finless porpoise, that is, the V-shaped skeleton. The first flexible part is located on the outside of the V-shaped skeleton and adheres to the outer structure. The second flexible part is located on the inside of the V-shaped skeleton. The hydrophone is embedded in the rear end of the V-shaped skeleton and is used to convert the acoustic signal into an electrical signal. Since the flexible part has the characteristic of low sound speed, when the acoustic signal enters the flexible part, it will be gathered in it and propagate backward; at this time, the two flexible parts together constitute a channel for enhancing broadband sound wave transmission, and transmit the sound waves to the hydrophone. The above technical solution is based on the working principle of the sound receiving system of the finless porpoise to enhance the transmission and reception of sound waves, and has the advantages of wide-band and directional sound reception.

[0006] In some embodiments, a first socket is provided at the forked end, and a first connecting arm is formed on the outside of the first socket and a second connecting arm is formed on the inside; the second flexible member is provided with a second socket, and a third connecting arm is formed on one side of the second socket; the second connecting arm is embedded in the second socket; and the third connecting arm is embedded in the first socket.

[0007] In the above technical solution, the embedded design constructs a sound transmission channel: the sound waves incident from the front will penetrate the first connecting arm and enter the third connecting arm, and then propagate backward along the third connecting arm to the hydrophone; such a transmission channel can directionally transmit sound energy to the hydrophone, thereby enhancing the effect of sound reception.

[0008] In some embodiments, a first flexible member is fixedly disposed on the outside of the first connecting arm, and the first flexible member is wrapped around the outside of the second connecting arm with the closed end of the first socket as the starting point and the end point of the first connecting arm as the end point.

[0009] In the above technical solution, the first flexible member plays a role in guiding the sound waves, guiding the sound waves to penetrate the first connecting arm and enter the sound transmission channel, thereby enhancing the reception of the sound waves.

[0010] In some embodiments, the first socket has a width of 3.0-5.0 mm.

[0011] In the above technical solution, the first socket allows the third connecting arm to be embedded therein to form an acoustic waveguide, thereby promoting the directional transmission of sound waves.

[0012] In some embodiments, the thickness of the first connecting arm is 2.5-3.0 mm; the thickness of the second connecting arm is 2.0-3.0 mm.

[0013] In the above technical solution, the first connecting arm is configured to be thin enough to allow sound waves to penetrate effectively. This penetration effect is angle-dependent, and sound waves incident at different angles have different receiving responses, thereby forming receiving directivity.

[0014] In some embodiments, the angle of the V-shaped skeleton is 30-50°.

[0015] In the above technical solution, the V-shaped skeleton helps to form a forward sound reception directivity.

[0016] In some embodiments, the propagation speed of sound waves in the first flexible member and the second flexible member is lower than the propagation speed of sound waves in water.

[0017] In the above technical solution, according to the ray acoustics theory, it is known that the sound ray, that is, the propagation direction of sound energy, always bends towards the low sound speed region. Therefore, in order to better converge sound waves, through the above technical solution, the sound waves can be converged therein after entering the flexible member and propagate backward. The two flexible members together form a channel for enhancing broadband sound wave transmission, and conduct the sound waves to the hydrophone. This technical solution helps to improve the sensitivity of sound wave reception.

[0018] In some embodiments, the materials of the first flexible member and the second flexible member are silicone.

[0019] In the above technical solution, silicone is a flexible material, which can achieve good contact with the surface of the hydrophone and helps to improve the sound wave reception efficiency of the hydrophone.

[0020] In some embodiments, the first flexible member and the second flexible member are adhered to the V-shaped skeleton by silicone glue.

[0021] In the above technical solution, silicone glue has the advantages of high strength and strong flexibility. And although silicone glue will harden to a certain extent, its acoustic properties are still in good compatibility with silicone after hardening, so the impact on the performance of the device is small. Compared with other adhesion methods, silicone glue is the best solution.

[0022] In some embodiments, the V-shaped skeleton is made of aluminum.

[0023] In the above technical solution, in addition to the characteristic of light weight, the aluminum material has a sufficiently large acoustic impedance, which can allow the sound waves in the front to pass through while blocking the sound waves on the side, providing sound reception directivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic perspective view of an embodiment of an underwater sound reception device imitating a finless porpoise of the present invention;

[0026] Figure 2 This is a schematic top - view structure diagram of an embodiment of a dolphin - imitating underwater acoustic receiving device of the present invention;

[0027] Figure 3 This is a test result graph of the receiving gain of an embodiment of the present invention;

[0028] Figure 4 This is a test result graph of the receiving directivity at 32 kHz of Embodiment 3 of the present invention. Specific Embodiments

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be specifically noted that the following embodiments are only used to illustrate the present invention, but do not limit the scope of the present invention. Similarly, the following embodiments are only partial embodiments of the present invention rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0030] In order to cope with the complex and changeable underwater environment, the finless porpoise has evolved an excellent biological sonar system, which includes an outstanding underwater acoustic receiving system. The underwater acoustic receiving system of the finless porpoise can be regarded as a broadband acoustic impedance matcher, which promotes the effective transmission of acoustic energy and helps in the reception of broadband sound waves. In view of this, the purpose of the present invention is to propose an underwater acoustic receiving device imitating the finless porpoise. By referring to the organizational structure characteristics of the finless porpoise's acoustic receiving system, bionic combination design is carried out to enhance the transmission and reception of broadband sound waves. In addition to the characteristics of simple structure and easy implementation, the present invention also has advantages such as broadband and directional acoustic reception.

[0031] Please refer to Figure 1 、 Figure 2 , the device includes a V - shaped framework 1, a first flexible member 2, a second flexible member 3 and a hydrophone 4. The overall structure of the embodiment of the present invention is symmetrically distributed left and right, in a "V" shape. The included angle of the V - shaped framework is 30 - 50°. It should be noted that adjusting the size of the included angle will affect the acoustic receiving directivity of the device. The V - shaped framework imitates the lower jawbone of the finless porpoise, and its tip parts are separated, but combining them will not have a great impact on the performance of the device, so this will not be further elaborated in this case. As a preferred solution, the angle is preferably 42°, and the advantage is to form a forward acoustic receiving directivity.

[0032] In this embodiment, the V-shaped framework is made of aluminum. In order to further improve the directivity of sound reception, the V-shaped framework 1 in this embodiment is made of aluminum material. It should be noted that the function of the V-shaped framework is to provide sound reception directivity, that is, to allow the sound waves in the front to pass through while blocking the sound waves on the side. Compared with resin and polymer materials, the sound impedance of metal is greater and it can play a better role. In addition, considering weight reduction, aluminum material is preferred. First flexible members 2 are fixedly provided on the outer sides of the two bifurcated ends of the V-shaped framework; second flexible members 3 are fixedly provided on the inner sides of the two bifurcated ends of the V-shaped framework 1, and hydrophones are embedded in the second flexible members 3; the two hydrophones 4 are arranged parallel to each other. The advantage of parallel arrangement is that the two hydrophones can form a symmetric reception directivity, which is helpful for target orientation.

[0033] The bifurcated end is provided with a first socket, and the width of the first socket is 3.0–5.0 mm. As a preferred solution, the width is set to 3.5 mm, allowing the third connecting arm to be embedded therein to form a sound waveguide, which has the advantage of enhancing the directional transmission of sound waves. It should be noted that the second flexible member is mainly embedded in the first socket to construct a sound transmission channel; when the sound waves propagate from the front to the device, they will first penetrate the first connecting arm (similar to a thin-wall structure) and enter the third connecting arm, and then propagate backward along the third connecting arm to the hydrophone; such a transmission channel can conduct sound energy to the hydrophone directionally, achieving the effect of enhancing sound reception.

[0034] A first connecting arm 1a is formed on the outer side of the first socket, and a second connecting arm 1b is formed on the inner side; the second flexible member 3 is provided with a second socket, and a third connecting arm 3a is formed on one side of the second socket; the third connecting arm 3a is embedded in the first socket; the second connecting arm 1b is embedded in the second socket. The first flexible member 2 is fixedly provided on the outer side of the first connecting arm 1a, and the second flexible member 3 wraps around the outer side of the second connecting arm 1a with the closed end of the first socket as the starting point and the end of the first connecting arm 1a as the ending point. Specifically, a bifurcated structure is formed in the middle of the V-shaped framework 1, and two thin-wall structures are formed at the rear end, namely the first connecting arm 1a and the second connecting arm 1b.

[0035] Both the first flexible member 2 and the second flexible member 3 are made of silicone material, and its material characteristics are low sound attenuation rate and sound speed lower than that of water (about 1050 m / s). It should be noted that in this case, silicone is a relatively preferred solution, and in addition to silicone, other materials with a sound wave propagation speed lower than 1200 m / s can be selected, such as doped hydrogel, doped polyurethane, etc., which will not be further described in this case. The first flexible member 2 is located on the outer side of the V-shaped framework 1 and adheres to the first connecting arm 1a.

[0036] The second flexible member 3 is located inside the V-shaped framework 1, filled between the first connecting arm 1a and the second connecting arm 1b, and extends backward. The hydrophone 4 is embedded at the rear end of the second flexible member 3 and is used to convert acoustic signals into electrical signals. The thickness of the first connecting arm 1a is 2.5–3.0 mm; the thickness of the second connecting arm 1b is 2.0 - 3.0 mm. As a preferred solution, the thickness of the first connecting arm 1a is 2.7 mm and the thickness of the second connecting arm 1b is 2.5 mm, which has the advantage of enhancing the receiving directivity. It should be noted that since sound waves bend towards the medium with a lower sound speed, the first flexible member with a lower sound speed can guide the sound waves into it; and since sound waves can more easily penetrate the first connecting arm, as long as the first flexible member is wrapped outside the first connecting arm, the sound waves incident into it can further penetrate the first connecting arm and enter the sound transmission channel mentioned above. The second connecting arm (inner thin wall) can, to a certain extent, prevent the sound waves that enter the sound transmission channel from escaping from the transmission channel again and plays a role in blocking the sound waves. At the same time, in terms of acoustic principles, the overall size of the device and the operating frequency are generally negatively correlated, that is, the larger the overall size of the device (under the premise that the proportion remains unchanged), the lower the operating frequency band. In view of this, the above size parameters are obtained based on the acoustic principles in this case.

[0037] In this embodiment, the propagation speed of sound waves in the first flexible member 3 and the second flexible member 2 is lower than the propagation speed of sound waves in water. According to the ray acoustics theory, the sound ray, that is, the propagation direction of sound energy, always bends towards the region with a lower sound speed. Therefore, in order to better converge the sound waves, through the above technical solution, the sound waves will be converged in it after entering the flexible member and propagate backward. The two flexible members together form a channel for enhancing the broadband sound wave transmission and conduct the sound waves to the hydrophone. This technical solution helps to improve the sensitivity of sound wave reception. As a preferred solution, the materials of the first flexible member 3 and the second flexible member 2 are silicone. Silicone is a flexible material and can achieve good contact with the surface of the hydrophone. Its advantage is to improve the receiving efficiency of the hydrophone for sound waves.

[0038] The working principle of the present invention is: According to the ray acoustics theory, the sound ray, that is, the propagation direction of sound energy, always bends towards the region with a lower sound speed. Since both the second flexible member 2 and the first flexible member 3 have the characteristic of a lower sound speed, the sound rays will be converged in the bionic flexible material after entering and propagate backward. At this time, the second flexible member 2 and the first flexible member 3 together form a channel for enhancing the broadband sound wave transmission and conduct the sound waves to the hydrophone 4. In addition, the thin wall structure at the middle and rear ends of the V-shaped framework 1 is thin enough for the sound waves to effectively penetrate, but this penetration effect has an angular dependence, which means that the sound waves incident at different angles have different receiving responses, thus forming a sound receiving directivity.

[0039] The relative sensitivity test results of the embodiments of the present invention are as Figure 3As shown. The embodiment of the present invention has flat and high receiving sensitivity in the frequency range of 15 kHz - 90 kHz, and the fluctuation within the frequency band is less than 5 dB.

[0040] The test result of the receiving directivity of Embodiment 3 of the present invention at 32 kHz is as Figure 4 shown. At the operating frequency of 32 kHz, the hydrophones 4 on both the left and right sides of the embodiment of the present invention both form acoustic receiving directivities, and the peak values of the receiving responses are located at -6° and 7° respectively, and the -3dB angular widths are 30° and 32° respectively.

[0041] In summary, based on the research idea of bionics, the designed porpoise-like acoustic receiving device of the present invention can enhance the transmission and reception of broadband sound waves and form an acoustic receiving directivity in a wide frequency band. Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention constructs a porpoise-like underwater acoustic receiving device based on the working principle of the acoustic receiving system of porpoise animals. The present invention enhances the transmission and reception of wide-frequency sound waves by combining and designing the bionic structure. In addition to the characteristics of simple structure and easy implementation, the present invention also has the advantages of wide frequency band, directional acoustic reception, etc.

[0042] The above are only partial embodiments of the present invention, and thus do not limit the protection scope of the present invention. Any equivalent device or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. An underwater acoustic receiving device imitating the finless porpoise, characterized in that, Comprising: A V-shaped framework; first flexible members are fixedly provided on the outer sides of the two bifurcated ends of the V-shaped framework; second flexible members are fixedly provided on the inner sides of the two bifurcated ends of the V-shaped framework, and hydrophones are embedded in the second flexible members; the two hydrophones are arranged in parallel with each other; A first socket is provided at the bifurcated end, a first connecting arm is formed on the outer side of the first socket, and a second connecting arm is formed on the inner side; a second socket is provided on the second flexible member, and a third connecting arm is formed on one side of the second socket; the second connecting arm is embedded in the second socket; the third connecting arm is embedded in the first socket; A first flexible member is fixedly provided on the outer side of the first connecting arm, and the first flexible member wraps around the outer side of the second connecting arm with the closed end of the first socket as the starting point and the end of the first connecting arm as the ending point; The materials of the first flexible member and the second flexible member are silicone; The V-shaped framework is made of aluminum alloy.

2. The underwater acoustic receiving device imitating a finless porpoise according to claim 1, wherein The width of the first socket is 3.0 - 5.0 mm.

3. The underwater acoustic receiving device imitating a finless porpoise according to claim 1, wherein The thickness of the first connecting arm is 2.5 - 3.0 mm; the thickness of the second connecting arm is 2.0 - 3.0 mm.

4. The underwater acoustic receiving device imitating a finless porpoise according to claim 1, wherein The included angle of the V-shaped framework is 30 - 50°.

5. The underwater acoustic receiving device imitating a finless porpoise according to claim 1, wherein The propagation speed of sound waves in the first flexible member and the second flexible member is lower than the propagation speed of sound waves in water.

6. The underwater acoustic receiving device imitating a finless porpoise according to claim 1, wherein The first flexible member and the second flexible member are adhered to the V-shaped framework by silicone glue.

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