Acoustic superstructure dynamic regulation and control device and method based on variable structure

Abstract

The invention relates to the technical field of underwater acoustic superstructures and acoustic camouflage, in particular to an acoustic superstructure dynamic regulation and control device and method based on a variable structure, and is suitable for deep sea equipment. The superstructure is of a hexagonal honeycomb structure, and each unit comprises a metal framework, a rubber layer, a push rod mechanism and a water cavity. The metal framework comprises a bottom plate, a side wall and six independent sectional type top plates, each top plate is connected with the side wall through a hinge, and a through hole is formed in the center of each top plate to form a Helmholtz resonant cavity neck; the rubber layer is attached to the inner surfaces of the bottom plate and the side wall; the push rod mechanism comprises a hydraulic push rod and a driving device. The hydraulic push rod is embedded in the rubber layer and hinged to the top plate. The top plate is closed in the silent mode to form an efficient sound absorption structure so as to reduce target acoustic characteristics, the intensity and spatial distribution of a reflected sound field are actively regulated and controlled by adjusting opening and closing of the top plate in the camouflage mode, and switching from acoustic stealth to dynamic camouflage is achieved. The method is suitable for acoustic stealth and acoustic camouflage tasks of deep sea equipment in a complex acoustic environment.

Description

Technical Field

[0001] This invention relates to the field of underwater acoustic superstructure and acoustic camouflage technology, specifically to a dynamic control device and method for acoustic superstructure based on deformation. Background Technology

[0002] The core requirement for deep-sea equipment is to minimize the intensity of acoustic targets in a silent state to avoid active sonar detection, and to actively change acoustic characteristics during maneuvering, thereby interfering with or deceiving active sonar detection systems by adjusting the parameters of the reflected sound field to achieve dynamic camouflage.

[0003] Currently, underwater acoustic control is mainly divided into two categories. One category is stealth technology based on sound absorption principles, which primarily employs rubber-based composite materials, porous sound-absorbing materials, or traditional Helmholtz resonant cavity structures. By absorbing the energy of incident sound waves, it reduces the intensity of its reflected signal, thereby achieving acoustic stealth. The other category is camouflage technology based on active jamming principles. This involves releasing jamming 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, these two types of technologies are usually designed and deployed independently, making it difficult to meet the full-condition requirements of deep-sea equipment and presenting significant limitations: (1) The sound-absorbing structure is usually fixed, such as the traditional Helmholtz resonator. Its structural parameters, such as cavity volume and neck size, are fixed after manufacturing, resulting in a fixed optimal sound-absorbing frequency band. It cannot be dynamically adjusted according to the changes in the active sonar detection frequency band, making it difficult to adapt to different working conditions or different detection frequencies.

[0005] (2) Based on active sound camouflage technology, although it can interfere with active sonar detection, it is designed and deployed separately from passive sound absorption technology, making it difficult to achieve rapid switching between the two functions. Moreover, active sound is easily identified by electronic countermeasures. Summary of the Invention

[0006] The purpose of this invention is to overcome the functional separation and lack of dynamic adaptive capability of existing underwater acoustic control technologies, and to provide a dynamic control method based on a variable-structure acoustic superstructure. This method integrates efficient sound absorption in silent mode and dynamic camouflage in maneuvering mode on the same physical structure. The proposed variable-structure acoustic superstructure dynamic control method achieves rapid switching between efficient sound absorption and dynamic sound field control through mechanical deformation, significantly improving the acoustic adaptive capability and flexibility of deep-sea equipment, thereby realizing acoustic advantages under all operating conditions.

[0007] To achieve the above objectives, this invention provides a dynamic control method for acoustic superstructures based on structural modification. The superstructure unit is a hexagonal honeycomb structure unit, comprising a metal skeleton, a rubber layer, a pusher mechanism, and a water cavity. The metal skeleton includes a segmented top plate, side walls, and a bottom plate. The segmented top plate is composed of six independent plates that can open at any angle, with a perforation in the middle forming the neck of the Helmholtz resonant cavity. The six segmented top plates are connected to the top of the side walls via hinges. The rubber layer is applied to the inner surfaces of the side walls and the bottom plate to achieve acoustic impedance matching, enhance sound absorption performance, and ensure structural sealing. The pusher mechanism includes six hydraulic pushers and a driving device. The top ends of the pushers are hinged to the lower surface of the segmented top plates, and the bottom ends pass through a sealing perforation in the bottom plate and connect to the driving device. The driving device is used to independently control each hydraulic pusher to perform linear reciprocating motion along the side wall direction to change the opening state of the top plate and achieve dynamic control of the external sound field.

[0008] Optionally, the perforation size on the base plate matches the outer diameter of the hydraulic push rod, and a dynamic seal is achieved through a rubber layer to ensure the isolation of the bottom of the superstructure unit from the water environment.

[0009] Optionally, the drive device is an electric hydraulic control system that can receive external commands and independently and precisely control the displacement of each hydraulic push rod.

[0010] The key design method of this invention lies in the regulation of the working mode of the above-mentioned acoustic superstructure, specifically including the following two modes.

[0011] Silent Stealth Mode: The submersible's central controller controls the drive unit based on external sound field signals, bringing all hydraulic push rods to their initial positions and completely closing the six segmented top plates. At this time, the top surface of the unit is nearly sealed, with perforations serving as the primary sound wave inlet. The unit as a whole constitutes a highly efficient Helmholtz resonant sound-absorbing cavity. When sound waves are incident, the water cavity entering the cavity through the perforations vibrates strongly. Sound energy is efficiently converted into heat energy through viscous dissipation and thermal transmission effects, exhibiting extremely strong absorption capabilities for specific low-frequency sound waves. This significantly reduces the acoustic target intensity of the submersible, making it difficult to detect with active sonar.

[0012] The core of the dynamic camouflage mode is based on real-time acoustic environment feedback, precisely controlling the number and angle of opening and closing of the segmented top panel, thereby achieving dynamic regulation of the reflected sound field. The specific implementation process is as follows: Step S1: Distribute multiple underwater acoustic sensors evenly in an array on the surface of the deep-sea equipment to collect incident sound wave signals from the surrounding environment in real time. The incident sound wave signals include acoustic characteristic parameters such as sound wave frequency, sound pressure level, and incident direction.

[0013] Step S2: The analog signal collected by the sensor is converted into a numerical signal by the data acquisition card and transmitted to the central sensor. The central sensor preprocesses the digital signal. First, it uses a finite impulse response filter for filtering. Then, it uses Fourier transform to convert the time domain signal into a frequency domain signal to extract the characteristic parameters of the sound wave. Finally, it normalizes the characteristic parameters and converts the data into a standardized format of the system scale.

[0014] Step S3: Based on the preprocessed acoustic signal feature parameters, the BP neural network model is used to calculate the number of opening and closing of the top plate and the opening and closing angle. First, the database corresponding to the opening and closing angle and the number of opening and closing is calculated by simulation. The neural network model is then optimized by discrete training. Then, based on reverse design, the corresponding opening and closing angle and the number of opening and closing are predicted in reverse according to the preprocessed acoustic signal.

[0015] Step S4: The drive unit receives instructions from the central controller to independently control the movement of the corresponding water pressure push rod, pushing the segmented top plate to rotate around the hinge axis to the target angle.

[0016] Through the above control process, the reflected sound field can be precisely controlled. By differentiating the opening and closing angles of the top plate and the combination of opening and closing, the scattered sound field can present different distribution forms such as uniform scattering, directional scattering, and multi-peak scattering. When it is necessary to simulate the scattering characteristics of marine environmental noise, the top plate is controlled to open and close randomly to change the spatial distribution of the scattered sound field. When it is necessary to form false acoustic targets, the unit top plates in specific areas are controlled to open and close synchronously to form scattering peaks with concentrated intensity, so that the target imaging of the active sonar deviates from the actual size.

[0017] The beneficial effects of this invention are as follows: (1) The integration and rapid switching of two acoustic functions, efficient sound absorption and dynamic sound field control, are realized on the same physical structure, which greatly improves the acoustic adaptability and flexibility of deep-sea equipment.

[0018] (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 manipulated, providing a physical basis for realizing acoustic deception, simulating environmental noise or avoiding detection in a specific direction.

[0019] (3) The acoustic characteristics are changed by mechanical modification. Compared with active electronic interference, the structure is simple, energy consumption is low, and reliability is high. Moreover, its acoustic response is derived from the change of physical structure, which is difficult to be identified and interfered with by electronic countermeasures.

[0020] (4) The hexagonal honeycomb structure unit is compact and easy to array to form a large area acoustic coverage layer. Each unit can be controlled independently, and through spatial synergistic configuration, a more macroscopic acoustic control effect can be achieved. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the acoustic superstructure unit in the example of the present invention, with the top plate closed.

[0022] Figure 2 This is a schematic diagram illustrating the dynamic control of the acoustic superstructure unit in an example of the present invention.

[0023] Figure 3 This is a schematic diagram of the top plate opening of the acoustic superstructure unit in the example of this invention, with a 15° opening.

[0024] Figure 4 The images show the scattered sound pressure cloud maps of the segmented top plate at 0° and 15° in the example of the present invention, where (a) is the scattered sound pressure cloud map of the segmented top plate at 0° and (b) is the scattered sound pressure cloud map of the segmented top plate at 15°.

[0025] Figure 5 This is a schematic diagram of a multi-unit sound-absorbing panel in an example of the present invention.

[0026] The attached diagram is labeled as follows: 1. Water cavity; 2. Segmented top plate; 3. Hydraulic push rod; 4. Side wall; 5. Rubber layer; 6. Drive device; 7. Base plate. Detailed Implementation

[0027] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0028] Example 1 like Figure 1 As shown, this embodiment provides an underwater acoustic superstructure unit based on dynamic deformation.

[0029] The metal frame is made of stainless steel, with a base plate 7, side walls 4 and six segmented top plates 2. The side walls 4 and the base plate 7 are integrally welded to ensure structural airtightness. The six segmented top plates 2 are installed on the top edge of the side walls 4 by micro waterproof hinges. A circular perforation is opened in the center of each segmented top plate 2 to form the neck of the Helmholtz resonant cavity.

[0030] The rubber layer 5 is made of butyl rubber, cast by a mold, and tightly adheres to the inner surfaces of the side wall 4 and the bottom plate 7. Its uniform thickness ensures acoustic impedance matching and sealing performance. The cavity formed by the segmented top plate 2 and the rubber layer serves as the water cavity 1.

[0031] In the push rod mechanism, six hydraulic push rods 3 are evenly embedded in the rubber layer 5. The piston rod tip of each hydraulic push rod 3 is connected to the lower surface of the corresponding segmented top plate 2 via a ball joint. The bottom of the hydraulic push rod 3 passes through a hole of corresponding size on the bottom plate 7, and the cylinder ends of all hydraulic push rods 3 are connected to a miniature electric hydraulic drive device 6 integrated in the center of the bottom of the unit. The drive device 6 has a built-in control chip that can receive external commands and independently control the extension and retraction stroke of each hydraulic push rod 3.

[0032] When deep-sea equipment is on standby, it needs to minimize the intensity of its acoustic targets. At this time, the acoustic superstructure is in a silent stealth mode with efficient sound absorption.

[0033] Drive unit 6 receives a command to bring all six hydraulic push rods 3 to their initial state, such as... Figure 1 As shown. Under the tension of the water pressure push rod 3 and the preload of the hinge, the six segmented top plates 2 are tightly closed, with minimal gaps between adjacent plates. The top of the unit forms a nearly closed surface, communicating with the external water body only through perforations on the six top plates. In this state, the acoustic superstructure unit constitutes a classic Helmholtz resonant cavity. The structural parameters such as 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 sound waves of this frequency are incident, the water column entering the cavity through the perforations generates strong vibrations, and the acoustic energy is efficiently converted into heat energy through viscous dissipation and thermal conduction effects. At the same time, the acoustic impedance of the rubber layer 5 matches that of the water, and as a viscoelastic material, the rubber can convert acoustic energy into heat energy dissipation through internal friction, and the damping dissipation effect effectively widens the sound absorption bottom width. When a deep-sea equipment acoustic covering layer composed of multiple acoustic superstructure units has a strong noise reduction capability for active sonar detection waves in a specific frequency band, it significantly reduces the acoustic target intensity of the deep-sea equipment, making it difficult to distinguish on the sonar screen and achieving deep concealment.

[0034] When deep-sea equipment needs to maneuver, pass through specific waters, or perform missions, it needs to change its original acoustic characteristics to cope with active sonar detection. At this time, the acoustic metastructure needs to switch to dynamic camouflage mode.

[0035] Underwater acoustic sensors deployed on the surface of deep-sea equipment collect incident sound wave signals from the surrounding environment in real time. The sensors convert analog signals into digital signals and extract key feature parameters through finite impulse response filters, Fourier transforms, and normalization preprocessing. These parameters are then input into a BP neural network model to calculate the opening and closing angle and number of openings and closings of the top plate. The drive device 6 receives the relevant instructions and drives the corresponding hydraulic push rod 3 to move the top plate. The opening and closing of the top plate and the entire structural transformation process are completed in a very short time.

[0036] like Figure 2 and Figure 3As shown, after the six top plates are opened, the effective acoustic opening area at the top of the unit increases. The Helmholtz resonance effect weakens, and the sound absorption coefficient of the acoustic superstructure unit at a specific frequency decreases. The acoustic superstructure unit transforms from a highly efficient sound absorber into a composite acoustic interface that partially absorbs and partially reflects sound. The overall reflected sound intensity is significantly enhanced compared to the silent mode. Simultaneously, by independently controlling the opening and closing states and angles of the top plates in different orientations, the morphology of the acoustic interface at the top of the unit and the local acoustic impedance can be altered, thereby changing the direction of sound scattering and causing the reflected sound wave direction to deviate from the specular reflection direction. This adaptive control of the reflected sound wave causes the echo signal intensity of the active SANA detection to continuously change and become azimuthally ambiguous, increasing the difficulty of target identification and tracking. Furthermore, the change in the direction of the reflected sound wave generates false acoustic images that do not conform to the actual geometry of the submersible, misleading the opponent's judgment of the target's size, attitude, or number.

[0037] Furthermore, to verify the influence of the number and angle of opening / closing on acoustic characteristics, acoustic superstructure unit models were established in two states: the top plate is completely closed and all six top plates are opened to 15°. Finite element simulations were performed on the acoustic superstructure units in both states using pressure acoustics, thermoviscous acoustics, and solid mechanics modules. In pressure acoustics, a perfectly matched layer was used to simulate a non-reflective boundary, and plane wave incidence was set. The acoustic characteristics of the water cavity were also simulated using the pressure acoustics module. The mechanical properties of the metal skeleton and rubber layer were simulated using solid mechanics. The metal skeleton used built-in structural steel, and the rubber layer used butyl rubber. The slits between the perforations and the plates were simulated using the thermoviscous acoustics module to consider the influence of fluid viscosity and thermal conduction on sound wave propagation. The coupling boundary conditions between the various physical fields are set as follows: the water-steel interface is set as an acoustic-solid coupling boundary to characterize the interaction between sound pressure and structural vibration; the pressure acoustic module and the thermoviscous acoustic module use an acoustic-thermoviscous acoustic boundary; the slit and perforation interfaces with water are set as thermoviscous acoustic-structural boundaries. Free tetrahedral elements are used to discretize the model, ensuring that the minimum mesh size is less than one-sixth of the wavelength to guarantee model accuracy. The final result is as follows: Figure 4The acoustic superstructure unit shown in (a) and (b) exhibits scattered sound pressure cloud maps in two states. At the same frequency point, the external scattered sound field sound pressure cloud maps of the acoustic superstructure in the two states show significant differences. When the top plate is completely closed, the overall sound field is basically symmetrical about the central axis. This cloud map indicates that in silent mode, the superstructure unit effectively confines and dissipates the incident sound wave energy in the internal resonant cavity. When the six top plates are opened by 15°, the strong reflection area of ​​the scattered sound field is not uniformly distributed, its wavefront shape is distorted, and the symmetry of the energy diffusion sound field distribution to the side is broken, resulting in waves pointing in a specific direction. These characteristics prove that in camouflage mode, the opening of the top plate destroys the original resonant sound absorption mechanism, and the unit transforms into an acoustic interface dominated by reflection. At the same time, the opened top plate introduces an asymmetric acoustic impedance distribution, causing the main direction of the scattered sound field to deviate from the geometric mirror reflection direction and to excite multi-directional scattering. This provides direct physical field evidence for the aforementioned generation of false acoustic echoes and interference with active sonar judgment.

[0038] like Figure 5 As shown, multiple acoustic units described in this invention can be arranged in a hexagonal tessellation pattern on a two-dimensional plane and connected by a common support frame to form a large-area rigid acoustic superstructure panel. The drive device 6 behind each unit can be controlled by a central controller. According to the global acoustic camouflage strategy, the central controller sends control commands to each unit, coordinating the opening and closing states of multiple segmented top plates on the entire panel, thereby achieving sound field control on a macroscopic level, realizing an acoustic camouflage effect or dynamic control to adapt to different marine acoustic environments.

[0039] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this 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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