An allosteric-based acoustic superstructure dynamic regulation device and method

Abstract

The present application relates to underwater acoustic superstructure and acoustic camouflage technical field, specifically relates to a kind of acoustic superstructure dynamic regulation and control device and method based on variable structure, it is suitable for deep sea equipment.Superstructure presents hexagonal honeycomb structure, each unit includes metal skeleton, rubber layer, push rod mechanism and water cavity;Metal skeleton includes bottom plate, side wall and six independent sectional top plate, each top plate is connected with side wall by hinge, and central perforation is formed Helmholtz resonance cavity neck part;Rubber layer is attached to the inner surface of bottom plate and side wall;Push rod mechanism includes water pressure push rod and driving device, and water pressure push rod is embedded in rubber layer and is hinged with top plate.The top plate of the present application is closed to form an efficient sound absorption structure to reduce the target acoustic characteristics in the silent mode, and the intensity and spatial distribution of reflected sound field are actively regulated by adjusting the opening and closing of the top plate in the camouflage mode, the switching from acoustic stealth to dynamic camouflage is realized, and it is suitable for acoustic stealth and acoustic camouflage of deep sea equipment in complex acoustic environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of underwater acoustic superstructure and acoustic camouflage technology, and in particular to an acoustic superstructure dynamic regulation device and method based on variable structure. BACKGROUND

[0002] The core requirement of deep-sea equipment is to reduce acoustic target intensity to the maximum extent in a silent state to evade active sonar detection, and to actively change acoustic characteristics when maneuvering to interfere or deceive active sonar detection systems through regulation of reflected sound field parameters to achieve dynamic camouflage.

[0003] Currently, the field of underwater acoustic control is mainly divided into two categories. One is stealth technology based on sound absorption principles, mainly using rubber-based composite materials, porous sound-absorbing materials, or traditional Helmholtz resonator structures to reduce the intensity of reflected signals by absorbing incident sound waves, thereby achieving acoustic stealth. The other is camouflage technology based on active interference principles, which releases interference signals through active sound-emitting devices to interfere with the detection process of the opponent's sonar, achieving the effect of active camouflage.

[0004] However, the above two types of technology are usually designed independently and deployed separately, making it difficult to meet the full working condition requirements of deep-sea equipment, and there are obvious limitations:

[0005] (1) Sound-absorbing structures are usually fixed, such as traditional Helmholtz resonators, whose cavity volume and neck size and other structural parameters are fixed after manufacturing, resulting in a fixed optimal sound absorption frequency band that cannot be dynamically adjusted according to changes in the active sonar detection frequency band, making it difficult to adapt to different working conditions or different detection frequencies.

[0006] (2) Based on active sound-emitting camouflage technology, although it can interfere with active sonar detection, it is designed independently and deployed separately from passive sound-absorbing technology, making it difficult to quickly switch between the two functions, and active sound emission is easily identified by electronic countermeasures. SUMMARY

[0007] The present application aims to overcome the functional separation and lack of dynamic adaptive ability of existing underwater acoustic control technology and provides a dynamic regulation method for acoustic superstructure based on variable structure, which integrates efficient sound absorption in silent mode and dynamic camouflage in maneuvering mode on the same physical structure. The dynamic regulation method for acoustic superstructure based on variable structure proposed in the present application achieves rapid switching between efficient sound absorption and dynamic sound field regulation through mechanical variable structure, significantly improving the acoustic adaptive ability and flexibility of deep-sea equipment, thereby achieving acoustic advantages in all working conditions.

[0008] To achieve the above object, the application provides a dynamic regulation method of acoustic superstructure based on metamorphosis, the superstructure unit is a hexagonal honeycomb structure unit, which comprises a metal framework, a rubber layer, a push rod mechanism and a water cavity. The metal framework comprises a segmented top plate, a side wall and a bottom plate, the segmented top plate is composed of six independent plates with an angle that can be opened and closed arbitrarily, a perforated hole is arranged in the middle to form a neck part of a Helmholtz resonance cavity, and the six segmented top plates are connected with the top of the side wall through hinges. The rubber layer is attached to the inner surfaces of the side wall and the bottom plate, and is used for realizing acoustic impedance matching, enhancing sound absorption performance and ensuring structure sealing. The push rod mechanism comprises six water pressure push rods and a driving device, the top ends of the water pressure push rods are hinged to the lower surfaces of the segmented top plates, the bottom ends of the water pressure push rods pass through the sealing perforated holes in the bottom plate and are connected with the driving device, and the driving device is used for independently controlling each water pressure push rod to make linear reciprocating motion along the direction of the side wall, so as to change the opening state of the top plate and realize dynamic regulation of an external sound field.

[0009] Optionally, the size of the perforated hole in the bottom plate matches the outer diameter of the water pressure push rod, and dynamic sealing is realized through the rubber layer to ensure the isolation of the bottom of the superstructure unit from the water environment.

[0010] Optionally, the driving device is an electric water pressure control system, which can receive external instructions and independently and accurately control the displacement of each water pressure push rod.

[0011] The key design method of the application lies in the regulation of the working mode of the above-mentioned acoustic superstructure, which specifically includes the following two modes.

[0012] The silent stealth mode: the central controller of the underwater vehicle controls the driving device according to the external sound field signal, so that all the water pressure push rods are in the initial position, and the six segmented top plates are completely closed. At this time, the top surface of the unit is approximately closed, the perforated hole serves as the main sound wave inlet, and the unit as a whole constitutes a high-efficiency Helmholtz resonance sound absorption cavity. When sound waves are incident, the water cavity in the cavity produces strong vibration, and the sound energy is efficiently converted into heat energy through viscous dissipation and heat transfer effect, which has a strong absorption capacity for specific low-frequency sound waves, significantly reduces the acoustic target strength of the underwater vehicle, and makes it difficult to be detected by active sonar.

[0013] The core of the dynamic camouflage mode is to accurately control the opening and closing number and angle of the segmented top plate based on real-time acoustic environment feedback, and then realize dynamic regulation of the reflected sound field. The specific implementation process is as follows:

[0014] Step S1: a plurality of underwater acoustic sensors are arranged on the surface of the deep-sea equipment in a uniform array, and incident sound wave signals of the surrounding environment are collected in real time. The acoustic characteristic parameters included in the incident sound wave signals are sound wave frequency, sound pressure level and incident direction.

[0015] Step S2: The analog signal collected by the sensor is converted into a digital signal by the data acquisition card and transmitted to the central sensor, which pre-processes the digital signal, first filters it using a finite impulse response filter, then converts the time-domain signal into a frequency-domain signal through Fourier transform, extracts the characteristic parameters of the sound wave, and finally normalizes the characteristic parameters to convert the data into a standardized format calibrated by the system.

[0016] Step S3: Based on the pre-processed acoustic signal characteristic parameters, the opening and closing number and angle of the top plate are calculated using a BP neural network model, the corresponding database of opening and closing angle and number and acoustic parameters is calculated through simulation, the neural network model is optimized using discrete training, and then based on reverse design, the corresponding opening and closing angle and number are inversely predicted based on the pre-processed acoustic signal.

[0017] Step S4: The instructions of the driving device structure to the central controller independently control the movement of the corresponding water pressure push rod to push the segmented top plate to rotate around the hinge shaft to the target angle.

[0018] Through the above control process, the precision regulation and control of the reflected sound field are realized, and by differentiating the opening and closing of the top plate at different angles and the opening and closing combination mode, the scattered sound field can present different distribution patterns such as uniform scattering, directional scattering and multi-peak scattering, when the scattering characteristics of the ocean environment noise need to be simulated, the top plate is controlled to open and close randomly to change the spatial distribution of the scattered sound field, when a false acoustic target needs to be formed, the unit top plate in a specific area is controlled to open and close synchronously to form a concentrated scattering peak, so that the target imaging of the active sonar deviates from the actual size.

[0019] The beneficial effects of the present application are as follows:

[0020] (1) The integration and rapid switching of two acoustic functions of efficient sound absorption and dynamic sound field regulation are realized on the same physical structure, which greatly improves the acoustic adaptive ability and flexibility of deep sea equipment.

[0021] (2) By controlling the opening and closing state of the segmented top plate, the reflected sound intensity, direction and spatial distribution of the reflected sound field can be flexibly controlled, which provides a physical basis for realizing acoustic deception, simulating environmental noise or evading detection in a specific direction.

[0022] (3) The mechanical conformational change method is used to change the acoustic characteristics, compared with the active electronic interference method, the structure is simple, the energy consumption is low, the reliability is high, and the acoustic response is derived from the physical structure change, which is difficult to be recognized and interfered by electronic countermeasures.

[0023] (4) The hexagonal honeycomb structure unit is compact in structure and easy to arrange in an array to form a large-area acoustic cover layer. Each unit can be independently controlled, and through spatial synergistic reconfiguration, more macroscopic acoustic regulation effects can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The figure is a structure diagram of the acoustic superstructure unit in the example of the application with the top plate closed.

[0025] Figure 2 The figure is a dynamic regulation diagram of the acoustic superstructure unit in the example of the application.

[0026] Figure 3 The figure is a structure diagram of the acoustic superstructure unit in the example of the application with the top plate opened by 15°.

[0027] Figure 4 The figures are scattering sound pressure nephograms of the acoustic superstructure unit in the example of the application with the segmented top plate opened by 0° and 15°, wherein (a) is a scattering sound pressure nephogram of the acoustic superstructure unit with the segmented top plate opened by 0°, and (b) is a scattering sound pressure nephogram of the acoustic superstructure unit with the segmented top plate opened by 15°.

[0028] Figure 5 The figure is a schematic diagram of a multi-unit sound absorption panel in the example of the application.

[0029] In the figure, the reference signs are as follows: 1, water cavity; 2, segmented top plate; 3, water pressure push rod; 4, side wall; 5, rubber layer; 6, driving device; 7, bottom plate. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0031] Example 1

[0032] As shown in the figure, the present embodiment provides an underwater acoustic superstructure unit based on dynamic reconfiguration. Figure 1

[0033] The metal framework is made of stainless steel material to process the bottom plate 7, the side wall 4 and the six segmented top plates 2. The side wall 4 is integrally welded with the bottom plate 7 to ensure the structural sealing property. The six segmented top plates 2 are installed at the top edge of the side wall 4 through micro waterproof hinges. A circular perforation is formed in the center of each segmented top plate 2 to form the neck part of the Helmholtz resonance cavity.

[0034] ​The rubber layer 5 is made of butyl rubber and is formed by mold casting, tightly adhering to the inner surface of the side wall 4 and the bottom plate 7, with uniform thickness, ensuring the sound impedance matching effect and sealing performance. The cavity surrounded by the segmented top plate 2 and the rubber is used as the water cavity 1.

[0035] The six water pressure push rods 3 in the push rod mechanism are evenly embedded in the rubber layer 5. The top end of the piston rod of each water pressure push rod 3 is connected to the lower surface of the corresponding segmented top plate 2 through a spherical hinge. The bottom of the water pressure push rod 3 passes through a hole of corresponding size on the bottom plate 7, and the cylinder end of all water pressure push rods 3 is connected to a miniature electric water pressure driving device 6 integrated in the center of the bottom of the unit. The driving device 6 has a built-in control chip that can receive external instructions and independently control the extension and retraction of each water pressure push rod 3.

[0036] When the deep-sea equipment performs standby tasks, it needs to minimize its acoustic target strength. At this time, the acoustic superstructure is in the silent stealth mode of high-efficiency sound absorption.

[0037] The driving device 6 receives instructions to make all six water pressure push rods 3 in the initial state, as shown in FIG. Figure 1 Under the action of the pulling force of the water pressure push rod 3 and the pre-tightening force of the hinge, the six segmented top plates 2 are tightly closed, with minimal gaps between adjacent plates. The top of the unit forms an approximately closed surface, only communicating with the external water body through the perforations on the six top plates. In this state, the acoustic superstructure unit forms a classic Helmholtz resonant cavity. The water cavity volume, perforation diameter, and rubber thickness are carefully designed so that the resonant frequency of the unit falls within the detection frequency band of the active sonar. When the sound wave of this frequency enters, the water column entering the cavity through the perforation vibrates strongly, and the sound energy is efficiently converted into heat energy through viscous dissipation and heat conduction effects. At the same time, the acoustic impedance of the rubber layer 5 and the water is matched, and the rubber, as a viscoelastic material, can convert sound energy into heat energy through internal friction and dissipate it, effectively widening the sound absorption bottom width. When multiple acoustic superstructure units form an acoustic cover layer of the deep-sea equipment, they have strong sound-absorbing ability for the active sonar detection wave of a specific frequency band, significantly reducing the acoustic target strength of the deep-sea equipment, making it difficult to be distinguished on the sonar screen, and achieving deep concealment.

[0038] When the deep-sea equipment enters a maneuvering state and needs to pass through a specific water area or perform a task, it needs to change the original acoustic characteristics to cope with the detection of the active sonar. At this time, the acoustic superstructure needs to switch to the dynamic camouflage mode.

[0039] The underwater acoustic sensor of the deep-sea equipment surface arrangement collects the incident sound wave signals of the surrounding environment in real time. The sensor converts the analog signals into digital signals, and through finite impulse response filter, Fourier transform and normalization preprocessing, extracts the key feature parameters and inputs them into the BP neural network model to calculate the opening angle and opening number of the top plate. The driving device 6 receives the relevant instructions, drives the corresponding water pressure push rod 3 to push the top plate to move, and the opening and closing of the top plate is completed in a very short time.

[0040] As shown in Figure 2 and Figure 3 , the effective acoustic opening area of the unit top increases after the six top plates are opened. The Helmholtz resonance effect is weakened, the sound absorption coefficient of the acoustic superstructure unit at a specific frequency decreases, and the acoustic superstructure unit changes from a high-efficiency sound absorber to a composite acoustic interface that partially absorbs and partially reflects. The overall reflected sound intensity is significantly enhanced relative to the silent mode. At the same time, by independently controlling the opening and closing state and opening angle of the top plates in different directions, the acoustic interface morphology and local acoustic impedance of the unit top can be changed, and the sound scattering direction can be changed, so that the reflected sound wave deviates from the specular reflection direction. The adaptive regulation of the reflected sound wave makes the echo signal strength of the active sonar detection constantly change and the azimuth ambiguous, increasing the difficulty of target recognition and tracking. Secondly, the change of the reflected sound wave direction produces a false acoustic image that does not match the actual geometric shape of the submarine, misleading the other party's judgment of the target size, posture or number.

[0041] Further, in order to verify the influence of the opening number and opening angle on the acoustic characteristics, acoustic superstructure unit models of two states, i.e., the top plate completely closed and the six top plates all opened to 15°, are established. Finite element simulation is performed on the acoustic superstructure units in the two states by using the pressure acoustic module, the thermal viscous acoustic module and the solid mechanics module. In the pressure acoustic simulation, the perfect matched layer is used to simulate the non-reflective boundary, and the plane wave incidence is set. The acoustic characteristics of the water cavity are also simulated by using the pressure acoustic module. The mechanical properties of the metal skeleton and the rubber layer are simulated by using the solid mechanics. The built-in structural steel material is used for the metal skeleton, and the butyl rubber is used for the rubber layer. The slits between the perforations and the plates are simulated by using the thermal viscous acoustic module to consider the influence of fluid viscosity and heat conduction on sound wave propagation. The coupling boundary conditions between the physical fields are set as follows: the water and steel interface is set as an acoustic-structure coupling boundary to represent the interaction between sound pressure and structure vibration, the pressure acoustic module and the thermal viscous acoustic module are set as an acoustic-thermal viscous acoustic boundary, and the slits and perforations and the water interface are set as a thermal viscous acoustic-structure boundary. Free tetrahedral elements are used for discretization processing of the model to ensure that the minimum grid size is less than one sixth of the wavelength to ensure the accuracy of the model. Finally, the acoustic characteristics of the two states are obtained as shown in Figure 4The scattering sound pressure cloud maps of the acoustic superstructure units shown in (a) and (b) in the two states have significant differences in the external scattering sound field sound pressure cloud maps of the acoustic superstructure at the same frequency point. When the top plate is completely closed, the overall sound field is basically symmetrical about the center axis. The cloud map shows that, in the silent mode, the superstructure unit effectively traps and dissipates the incident sound wave energy in the internal resonance cavity. When the six top plates are opened by 15°, the strong reflection area of the scattering sound field is not uniformly distributed, the wave front shape is distorted, and the symmetry of the energy distribution to the lateral diffusion sound field is broken, and waves pointing to a specific direction appear. These features prove that, in the camouflage mode, the opening of the top plate destroys the original resonant sound absorption mechanism, and the unit is converted into a reflection-based acoustic interface. At the same time, the opened top plate introduces an asymmetric acoustic impedance distribution, causing the main direction of the scattering sound field to deviate from the geometric mirror reflection direction and exciting multi-directional scattering, thereby providing direct physical field evidence for the generation of false acoustic echoes mentioned above to interfere with the judgment of active sonar.

[0042] As shown in Figure 5 A plurality of acoustic units described in the application can be arranged in a hexagonal close-packed manner in a two-dimensional plane, connected by a common support frame, to form a large-area rigid acoustic superstructure panel. The driving device 6 behind each unit can be controlled by a central controller. The central controller sends control instructions to each unit according to the global acoustic camouflage strategy, coordinates the opening and closing states of the multiple segmented top plates on the entire panel, and thus realizes macroscopic sound field control and acoustic stealth clothing effect or dynamic control to adapt to different marine acoustic environments.

[0043] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A dynamic control device for acoustic superstructures based on altered configurations, characterized in that: The superstructure unit is a hexagonal honeycomb structure unit, including a metal skeleton, a rubber layer (5), a push rod mechanism and a water cavity (1); the metal skeleton includes a base plate (7), a side wall (4) and six independent segmented top plates (2), each segmented top plate (2) is connected to the side wall (4) by a hinge, and the segmented top plate (2) has a perforation in the center; the rubber layer (5) is applied to the inner surface of the base plate (7) and the side wall (4); the push rod mechanism includes six hydraulic push rods (3) and a drive device (6), the hydraulic push rods (3) are embedded in the rubber layer (5), their top ends are hinged to the segmented top plates (2), and their bottom ends pass through the base plate (7) and are connected to the drive device (6); the water cavity (1) is a closed cavity formed by the rubber layer (5) and the segmented top plates (2), and its initial state is hexagonal prism.

2. The dynamic control device for acoustic superstructure based on altered structure according to claim 1, characterized in that: The metal frame is made of stainless steel.

3. The dynamic control device for acoustic superstructure based on altered structure according to claim 1, characterized in that: The water pressure push rod (3) and the perforation of the base plate (7) achieve a dynamic seal through the rubber layer (5).

4. The dynamic control device for acoustic superstructure based on altered structure according to claim 1, characterized in that: The drive device (6) is an electric water pressure control system, which can independently control the displacement of each water pressure push rod (3).

5. The dynamic control device for acoustic superstructure based on altered structure according to claim 1, characterized in that: The opening angle of the segmented top plate (2) is continuously adjustable within the range of 0° to 15°, and each segmented top plate (2) is independently controlled.

6. A dynamic control method for acoustic superstructures based on metamorphic deformation, characterized in that: Using the dynamic control device based on a modified acoustic superstructure as described in any one of claims 1-5, including a silent stealth mode and a dynamic camouflage mode, the specific control steps are as follows: Silent Stealth Mode Control: When the deep-sea equipment is in a silent stealth state, the acoustic superstructure on the surface of the deep-sea equipment achieves a full absorption state of sound signals. The central controller controls the drive device (6) to make all the water pressure push rods (3) in the initial position and all the segmented top plates (2) close, so that the superstructure forms a Helmholtz resonant cavity with perforations as the main entrance of sound waves, achieving efficient sound absorption in specific target frequency bands; Dynamic camouflage mode control includes four steps: acoustic signal reception, signal preprocessing, opening / closing parameter calculation, and execution control, as detailed below: Step S1: Deploy underwater acoustic sensors on the surface of the deep-sea equipment to collect incident sound wave signals from the surrounding environment. The incident sound wave signals include acoustic characteristic parameters such as sound wave frequency, incident direction, and sound pressure level. Step S2: Convert the analog signal collected by the sensor into a digital signal, and extract the key feature parameters of the sound wave by passing it through a finite impulse response filter, Fourier transform and normalization. Step S3: Input the preprocessed feature parameters into the trained BP neural network model and output the number of opening and closing of the top plate and the opening and closing angle of each top plate; Step S4: The central controller of the deep-sea equipment controls the drive device (6) according to the model output command, drives the corresponding water pressure push rod (3) to move, and the water pressure push rod (3) pushes the segmented top plate (2) to rotate around the hinge to open, dynamically adjusting the reflection direction and reflection intensity of the unit on the incident sound wave, and realizing acoustic camouflage.

7. The method for dynamic control of acoustic superstructures based on metamorphic deformation as described in claim 6, characterized in that: In the dynamic camouflage mode control, by controlling the opening angle and number of the segmented top plate (2), the reflected sound intensity and sound scattering direction of the unit are changed, so that the reflected sound wave direction deviates from the mirror reflection direction.

8. The method for dynamic control of acoustic superstructures based on metamorphic deformation according to claim 6, characterized in that: Multiple hexagonal honeycomb structure units are arranged to form a large-area array panel. The segmented top plate (2) of different units in the array is coordinated and controlled by the central controller to present different opening and closing state combinations, forming a specific acoustic impedance spatial distribution on a macroscopic level, and realizing complex sound field control.

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