A ship ultrasonic antifouling method, device and equipment based on Lamb wave

Abstract

The application discloses a ship ultrasonic antifouling method and device based on Lamb waves, and belongs to the technical field of ship and marine antifouling. The method comprises the following steps: dividing the underwater plate of a ship into multiple protection zones; pre-storing the plate thickness parameters, the fouling risk weight coefficients and the adapted Lamb wave mode parameters corresponding to each protection zone; collecting the fouling coverage rate of the water side surface of each zone, and obtaining real-time impedance values through the electrical feedback signals of the transducing units; correcting the Lamb wave mode parameters of each zone according to the double-source feedback data, and dynamically adjusting the working power, the duty cycle of the transducing units of each zone and the excitation timing of the ultrasonic wave emitting units; and exciting the corrected Lamb waves in the plate through the transducing units. The technical scheme can realize large-area uniform antifouling of the ship body, intensified protection of key areas at the tail and energy-saving adaptive operation of the system.

Description

Technical Field

[0001] This application belongs to the field of marine antifouling technology, specifically relating to a method, device, and equipment for ultrasonic antifouling of ships based on Lamb waves. Background Technology

[0002] Marine organisms adhering to the underwater hull plating of ships increase drag and accelerate coating aging. Traditional antifouling methods, such as applying toxic antifouling paint, can easily cause marine pollution, while electrolytic seawater antifouling suffers from high energy consumption and complex maintenance. Existing ultrasonic antifouling solutions mostly use a single frequency to excite horizontal shear waves on the hull plating. While this can suppress fouling to some extent, it still has significant drawbacks: First, ultrasonic waves are prone to scattering and reflection when propagating through non-uniform hull plating (including longitudinal ribs, welds, and other reinforcing structures), forming numerous standing wave nodes and creating antifouling blind spots. Second, it does not consider plate thickness differences in mode matching, resulting in uneven antifouling effects between thin and thick plate areas. Third, it simply distinguishes between normal and energy-saving modes without dynamically managing differences in plate thickness, flow velocity, and fouling rate in different zones such as the bow, sides, and bottom, nor linking with ship navigation conditions to adjust parameters, leading to an unbalanced distribution of energy consumption across the entire ship. Fourth, it lacks a real-time feedback mechanism for fouling status and transducer operating status, making it difficult to adaptively correct modal parameters and prone to insufficient antifouling effect or cavitation damage to the hull. Therefore, there is an urgent need for an ultrasonic antifouling method that can achieve uniform antifouling of the entire ship, optimize energy efficiency, and has adaptive control capabilities. Summary of the Invention

[0003] This application provides a method, apparatus, and equipment for ultrasonic antifouling of ships based on Lamb waves. The purpose is to solve the technical problems of existing ultrasonic antifouling systems for ships, such as uneven coverage of a single mode, many blind spots, lack of dynamic control based on zoning characteristics and navigation conditions, and lack of adaptive feedback, which leads to low antifouling efficiency, high energy consumption, and easy cavitation damage.

[0004] In a first aspect, embodiments of this application provide a method for ultrasonic antifouling of ships based on Lamb waves, the method comprising: Step 1: Divide the underwater outer plating of the ship into multiple protective zones, and install transducer units and ultrasonic transmitting units on the inner surface of each zone. Step 2: Pre-store the plate thickness parameters, contamination risk weight coefficients and suitable Lamb wave mode parameters corresponding to each protection zone. The Lamb wave mode parameters include at least the frequency-thickness product and duty cycle of the A0 mode, S0 mode and their superposition modes. Step 3: Collect the fouling coverage rate of the water-side surface of each zone, and obtain the real-time impedance value through the electrical feedback signal of the transducer unit to form dual-source feedback data; Step 4: Correct the Lamb wave mode parameters of each zone based on the dual-source feedback data, and dynamically adjust the working power, duty cycle of the transducer unit of each zone and the excitation timing of the ultrasonic transmitting unit in conjunction with the current navigation conditions of the ship. Step 5: The modified Lamb wave is excited inside the outer plate through the transducer unit to form an anti-fouling sound field covering the surface of the hull.

[0005] Furthermore, the division of the protection zones is based on factors including hull location, plate thickness, and reinforcement structure characteristics, and is at least divided into the bow zone, side zone, bottom zone, and propeller / rudder zone. The selection of the Lamb wave mode parameters satisfies at least one of the following conditions: When the thickness of the protective partition plate is less than 15mm, the A0 mode with a frequency-thickness product in the range of 0.1-0.6MHz·mm is preferred. When the thickness of the protective partition plate is not less than 15mm, the S0 mode with a frequency-thickness product in the range of 0.5-1.5MHz·mm is preferred. When the protection zone contains a mixed distribution of plate thickness, time-multiplexed excitation of A0 mode and S0 mode is used; The A0 mode and the S0 mode are alternately excited with a preset duty cycle, so that their spatial interaction fields form a complementary coverage, and the time-averaged duty cycle of the node state at any spatial point of the outer plate does not exceed 15%.

[0006] Furthermore, the transducer unit is any one or more combinations of piezoelectric ceramic transducers, electromagnetic acoustic transducers, or magnetostrictive transducers. The Lamb wave operates in the frequency range of 15-80kHz, and the microscopic cavitation effect induced by the excited Lamb wave on the water-side surface acts on the early attachment stage of marine organisms.

[0007] Furthermore, the formula for calculating the contamination risk weighting coefficient λ is as follows: ; Where t is the average plate thickness of the partition, v is the average flow velocity of the partition, d is the distance from any point in the partition to the nearest transducer unit, t, v, and d are dimensionless, and k1, k2, and k3 are preset weighting coefficients. The main control unit prioritizes each partition based on the value of λ, with partitions having higher λ values ​​receiving priority allocation of antifouling resources.

[0008] Furthermore, step 4, which involves dynamically adjusting the ship's navigation conditions, specifically includes: When the ship's speed vs < 3kn, only the high-pollution-risk zone with λ ≥ 0.7 is activated, the transducer unit is controlled to operate with a single frequency and low duty cycle, and the ultrasonic transmitting unit is turned off. When 3kn≤vs<12kn, all partitions are enabled, and high-risk contamination partitions use the A0 and S0 superimposed mode, while low-risk partitions use the S0 mode. When vs≥12kn, the high-fouling-risk zone is controlled to maintain A0 mode, while the medium- and low-risk zone switches to S0 mode and the operating power decreases linearly with the increase of speed.

[0009] Furthermore, in step 3, the optical path component includes a light-transmitting window and a coupling lens located at the center of the transducer unit. After the illumination light passes through the outer plate, it illuminates the water-side surface. The reflected light returns along the original path and is received by the image sensor. The main control unit identifies the dirt coverage rate through an image processing algorithm. The electrical feedback signal includes the impedance amplitude, phase, and resonant frequency offset of the transducer unit.

[0010] Furthermore, step 4, correcting the Lamb wave mode parameters, includes: Based on the preset interval level into which the fouling coverage falls, a correction parameter corresponding to the preset interval level is determined, and the wave parameters of the current mode are dynamically corrected based on the correction parameter.

[0011] Furthermore, in step 4, the excitation timing of the ultrasonic transmitting unit is subjected to propeller-shaft synchronous phase modulation: The main control unit receives the propeller shaft angular position sensor signal and outputs the excitation pulse only within the 120° phase window when the blade rotates to the front of the transmitting unit. It also controls the sound pressure level to be within the adhesion suppression and non-erosion window of 140-150 dB re 1μPa @1m to avoid continuous cavitation erosion on the same blade.

[0012] Furthermore, step 4 also includes a standing wave node time shift avoidance strategy: The main control unit controls the transducer unit to cyclically switch between at least 3 different frequency points, with the frequency difference Δf between adjacent frequency points being ≥2kHz, so that the position offset of the standing wave node corresponding to the adjacent frequency point is ≥50mm.

[0013] Secondly, embodiments of this application provide a Lamb wave-based ultrasonic antifouling device for ships, the device comprising: The protection zone determination module is used to divide the underwater outer plate of the ship into multiple protection zones, and to install transducer units on the inner surface of each zone, as well as ultrasonic transmitting units. The modal parameter determination module is used to pre-store the plate thickness parameters, contamination risk weight coefficients and suitable Lamb wave modal parameters corresponding to each protection zone. The Lamb wave modal parameters include at least the A0 mode, the S0 mode, and the frequency-thickness product and duty cycle of their superimposed modes. The dual-source feedback data acquisition module is used to collect the fouling coverage rate of the water-side surface of each zone and obtain the real-time impedance value through the electrical feedback signal of the transducer unit to form dual-source feedback data. The modal parameter correction module is used to correct the Lamb wave modal parameters of each zone according to the dual-source feedback data, and dynamically adjust the working power, duty cycle and excitation timing of the ultrasonic transmitting unit of each zone in conjunction with the current navigation conditions of the ship. The anti-fouling sound field construction module is used to generate modified Lamb waves within the outer plate through the transducer unit, forming an anti-fouling sound field covering the hull surface.

[0014] Thirdly, embodiments of this application provide an electronic device including a processor, a memory, and a program or instructions stored in the memory and executable on the processor, wherein the program or instructions, when executed by the processor, implement the steps of the method described in the first aspect.

[0015] Fourthly, embodiments of this application provide a readable storage medium storing a program or instructions that, when executed by a processor, implement the steps of the method described in the first aspect.

[0016] Fifthly, embodiments of this application provide a chip, the chip including a processor and a communication interface, the communication interface being coupled to the processor, the processor being used to run programs or instructions to implement the method as described in the first aspect.

[0017] The technical solution provided in this application effectively eliminates the standing wave blind zone caused by the hull reinforcement structure through zoned differentiated modal matching and dual-source feedback self-correction, achieving uniform coverage of the antifouling field across the entire ship. By dynamically scheduling power and duty cycle in conjunction with navigation conditions such as speed and RPM, it significantly reduces the overall energy consumption of the ship while ensuring antifouling effectiveness in high-fouling areas. Furthermore, by combining closed-loop control with optical fouling monitoring and electrical impedance feedback, it can adaptively match the optimal modal parameters without manual intervention and precisely limit the sound pressure within the anti-attachment and non-corrosion window, balancing antifouling effect and hull structural safety. The overall antifouling efficiency is significantly improved, and the energy consumption control effect is excellent. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of the ultrasonic antifouling method for ships based on Lamb waves provided in the embodiments of this application; Figure 2 This is a schematic diagram of the antifouling method based on Lamb wave multimodal combination provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the ultrasonic antifouling device for ships based on Lamb waves provided in the embodiments of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, specific embodiments of this application will be described in further detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely for explaining this application and not for limiting it. It should also be noted that, for ease of description, only the parts relevant to this application are shown in the drawings, not all of them. Before discussing exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe operations (or steps) as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but may also have additional steps not included in the drawings. The process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0021] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0022] The following description, in conjunction with the accompanying drawings, details the Lamb wave-based ultrasonic antifouling method, apparatus, equipment, and medium for ships provided in this application, through specific embodiments and application scenarios.

[0023] Example 1 Figure 1 This is a schematic flowchart of the ultrasonic antifouling method for ships based on Lamb waves provided in the embodiments of this application. Figure 1 As shown, the specific steps include the following: Step 1: Divide the underwater outer plating of the ship into multiple protective zones, and install transducer units and ultrasonic transmitting units on the inner surface of each zone. The underwater hull plating of a ship can be all the steel hull plates below the waterline, and is divided into the inner surface on the side inside the cabin and the waterside surface on the side in contact with seawater.

[0024] Protection zones can be independent control areas defined based on the ship's hull structure, plate thickness, and fouling rate, such as the bow zone, side zone, bottom zone, and propeller / rudder zone.

[0025] The transducer unit can be a functional unit that fits onto the inner surface of the outer plate and is used to excite Lamb waves within the plate. The internal transducer element can be a piezoelectric ceramic, an electromagnetic acoustic, or a magnetostrictive element.

[0026] The propeller and rudder area can be the underwater area at the stern of a ship, which is composed of the propeller, rudder blades, propeller hub, shaft housing, and rudder stock. This area has fast seawater flow and the most severe marine organism attachment.

[0027] An ultrasonic transmitting unit can be a device that is watertightly installed through an opening in the hull and whose transmitting surface faces directly toward the seawater, radiating water body waves outward, which is different from a transducer that generates guided waves inward.

[0028] This solution allows the main control unit to retrieve ship hull drawings, plate thickness drawings, and reinforcement structure drawings. The built-in partitioning program completes the area boundary division, and each partition is assigned an independent drive channel for independent control. Construction personnel fix the transducer unit tightly against the inner surface of one side of each partition compartment without penetrating the ship's steel plate, thus avoiding damage to the ship's watertightness. The ultrasonic transmitting unit is also sealed and fixed, with the transmitting end completely facing the outer seawater.

[0029] Step 2: Pre-store the plate thickness parameters, contamination risk weight coefficients and suitable Lamb wave mode parameters corresponding to each protection zone. The Lamb wave mode parameters include at least the frequency-thickness product and duty cycle of the A0 mode, S0 mode and their superposition modes. Among them, A0 mode is the Lamb wave fundamental antisymmetric mode, and S0 mode is the Lamb wave fundamental symmetric mode.

[0030] The plate thickness parameter can be the actual measured thickness value of the steel outer plate of the corresponding protection zone, in mm, used to match and adapt the Lamb frequency thickness range.

[0031] The fouling risk weighting coefficient can be a calculation parameter that quantifies the ease with which marine organisms attach in different zones. The higher the value, the higher the priority of fouling prevention in that area.

[0032] Lamb wave mode parameters can be a set of mode operation control parameters stored in the main control unit, including control quantities such as mode type, frequency, frequency-thickness product, and single excitation duty cycle.

[0033] Superimposed modes can be a combined acoustic field formed by the synchronous or time-divisional excitation of A0 and S0 modes.

[0034] The frequency-thickness product can be the product of the Lamb wave operating frequency and the steel plate thickness, measured in MHz. mm is used to determine the current mode fit and is a core indicator for Lamb wave mode selection.

[0035] Duty cycle is the percentage of time a transducer unit is in an ultrasonic excitation state per unit time, used to regulate the intensity of ultrasonic energy output.

[0036] Specifically, before the ship leaves the factory, technicians can input the measured plate thickness, preset weights, and matching modal parameters of each zone into the local storage module of the main control unit, forming a zone parameter database that can be retrieved in real time. The main control unit database stores a set of frequency-thickness product and duty cycle parameters for each mode separately, supporting retrieval in both single-mode and dual-mode superposition operation modes.

[0037] Step 3: Collect the fouling coverage rate of the water-side surface of each zone, and obtain the real-time impedance value through the electrical feedback signal of the transducer unit to form dual-source feedback data; The optical path component can be a photoelectric monitoring structure integrated inside the transducer unit, including a light-transmitting window and a coupling lens. The illumination light can penetrate the steel plate to reach the seawater side, making it a non-contact fouling monitoring hardware.

[0038] The waterside surface can be the outermost plate of the ship's underwater hull that is in direct contact with seawater, and all marine organism attachment occurs on this surface.

[0039] Fouling coverage rate can be the percentage of the surface area of ​​marine organisms attached to the water side relative to the total area of ​​the zone, and is divided into three levels of fouling indicators: biofilm, algae, and hard shellfish.

[0040] The electrical feedback signal can be the electrical characteristic data of the transducer element collected in real time by the drive unit, including impedance, phase, resonance offset, etc., which is used to determine the matching status between the transducer unit and the steel plate.

[0041] Real-time impedance value can be the impedance amplitude of the transducer under the current operating state, used to determine whether there are problems such as impedance mismatch, steel plate scaling and loss.

[0042] Dual-source feedback data can be a comprehensive feedback dataset resulting from the fusion of two types of signals: optical contamination monitoring data and transducer unit electrical impedance data.

[0043] The optical path component features a built-in light source that projects illumination light onto a steel plate. The light penetrates the plate and illuminates the water-side surface. The reflected light returns along the same path to the image sensor, which transmits the image to the main control unit for image recognition and calculation, outputting a fouling coverage rate value. The drive unit has a built-in impedance acquisition circuit that continuously collects impedance data from the transducer element during operation and uploads it to the main control unit in real time, forming an electrical feedback data stream. The main control unit packages and associates the optical fouling data and electrical impedance data from the same zone at the same time, constructing a two-dimensional real-time feedback dataset to provide a basis for subsequent modal correction.

[0044] Step 4: Correct the Lamb wave mode parameters of each zone based on the dual-source feedback data, and dynamically adjust the working power, duty cycle of the transducer unit of each zone and the excitation timing of the ultrasonic transmitting unit in conjunction with the current navigation conditions of the ship. Navigation conditions can be a set of real-time operating parameters of a ship, including speed, main engine speed, draft, propeller speed, etc.

[0045] The operating power can be the ultrasonic excitation power output from the drive unit to the transducer unit, and it can be continuously adjusted within the rated power range.

[0046] The excitation timing can be the timing, phase, and period control logic of the ultrasonic pulses output by the ultrasonic transmitting unit, used to match the propeller rotation phase.

[0047] The main control unit retrieves dual-source feedback data, compares it with preset modal correction judgment rules, and automatically changes the zone operation mode, adjusts the frequency accumulation, and modifies the excitation duty cycle. The main control unit reads real-time navigation data through the ship's integrated monitoring system (onboard integrated monitoring platform), matches the corresponding power, duty cycle, and launch timing control strategy according to the speed range, and automatically and dynamically adjusts throughout the process without manual intervention.

[0048] Step 5: The modified Lamb wave is excited inside the outer plate through the transducer unit to form an anti-fouling sound field covering the surface of the hull.

[0049] The guiding wave field can be a structural elastic acoustic field formed by the propagation of Lamb waves along the hull steel plate. It exists only inside the steel plate and induces microscopic cavitation on the water-side surface to inhibit biofilm adhesion.

[0050] The composite anti-fouling acoustic field can be a two-layer synergistic anti-fouling acoustic environment formed by the combination of the guided wave acoustic field inside the plate and the underwater directional cavitation acoustic field.

[0051] The main control unit of this scheme can send the corrected modal parameters to the drive unit. The drive unit outputs a matching excitation signal to the transducer unit. The transducer element completes the electroacoustic conversion and generates a target Lamb wave inside the outer plate. The main control unit outputs a pulse signal to the tail-end transmitting unit according to the preset excitation sequence. The transmitting unit directs the ultrasonic energy into the seawater. The Lamb wave inside the steel plate propagates along the plate surface over a wide range, forming a continuous microscopic cavitation environment on the waterside surface of the entire ship. The directional ultrasound in the tail water constructs a local strong cavitation field. The two types of sound fields work together to complete the antifouling of the entire ship.

[0052] This technical solution constructs a complete ship ultrasonic antifouling solution with zoned dual-equipment layout, dual-source feedback, navigation linkage, and composite sound field coordination. It solves the defects of existing single-frequency single-mode ultrasonic antifouling solutions, such as uneven coverage and inability to adaptively adjust according to fouling and navigation status. It achieves uniform antifouling over a large area of ​​the hull, enhanced protection for key areas at the stern, and energy-saving adaptive operation of the system.

[0053] In one embodiment, optionally, the division of the protection zone is based on the hull part, plate thickness and reinforcement structure features, and is at least divided into the bow zone, side zone, bottom zone and propeller zone. The selection of the Lamb wave mode parameters satisfies at least one of the following conditions: When the thickness of the protective partition plate is less than 15mm, a frequency-thickness product of 0.1-0.6MHz should be preferred. mm of A0 mode; When the thickness of the protective partition plate is not less than 15mm, a frequency-thickness product of 0.5-1.5MHz should be preferred. mm of S0 mode; When the protection zone contains a mixed distribution of plate thickness, time-multiplexed excitation of A0 mode and S0 mode is used; The A0 mode and the S0 mode are alternately excited with a preset duty cycle, so that their spatial interaction fields form a complementary coverage, and the time-averaged duty cycle of the node state at any spatial point of the outer plate does not exceed 15%.

[0054] Among them, the reinforced structural features can be the thickened structures such as ribs, longitudinal bones, and reinforcing ribs attached to the hull steel plates. These structures will change the propagation dispersion characteristics of Lamb waves and serve as the basis for zoning.

[0055] The bow area refers to the underwater outer plating area at the bow of a ship, where seawater erosion is intense, and the plating is mostly thin.

[0056] The side hull area refers to the outer plating above and below the waterline on both sides of the ship, which is mostly made of medium-thick steel plates with dense reinforcing ribs.

[0057] The bottom area refers to the entire underwater outer plating of the ship's bottom, with a mixed distribution of plating thickness and a moderate rate of fouling adhesion.

[0058] The average duty cycle can be the percentage of time that a spatial standing wave node is in a state of zero amplitude. There is no ultrasonic effect at the node, which can easily form a blind spot for pollution prevention.

[0059] Standing wave nodes are points where the amplitude of ultrasonic standing waves inside the outer panel approaches zero, and are the root cause of pollution blind spots.

[0060] Time-reused excitation can be achieved by alternating output excitation in A0 and S0 modes over time, with the same set of transducers switching between the two modes at different time periods.

[0061] The main control unit reads the three-dimensional structural drawings of the hull and simultaneously extracts three types of information: part identification, plate thickness, and stiffener arrangement. It automatically divides the hull into four basic zones. For example, large bulk carriers can further subdivide the four zones into bottom and fore-and-aft sub-zones. The main control unit retrieves the plate thickness parameters of the zones and automatically matches the corresponding modal and frequency-thickness product intervals. If any judgment condition is met, the corresponding modal strategy can be executed.

[0062] Specifically, thin outer plates exhibit low A0 mode propagation attenuation and uniform sound field across the plate surface. For example, an 8mm thin plate at the bottom of a ship has a matching frequency thickness product of 0.3MHz. The A0 mode operates continuously for mm. Specifically, the S0 mode of thicker plates has stronger penetration capability and lower energy loss; for example, for an 18mm thick steel plate on the hull side, the selected frequency-thickness product is 1.0MHz. The S0 mode of mm. For example, if a 10mm thin plate and a 20mm thick plate exist in the partition at the same time, the main control unit alternately outputs A0 and S0 mode excitations to cover the two thicknesses of the plate in a time-division manner.

[0063] The main control unit controls the two modes to output in a fixed time sequence. The blind zone of the A0 mode standing wave and the blind zone of the S0 mode are staggered. The duration ratio of each node is calculated in real time, and the maximum is no more than 15%, avoiding blind zones that have no ultrasound coverage for a long time.

[0064] This technical solution uses a layered matching of plate thickness with a dedicated modal frequency-thickness product range. It employs time-division multiplexing excitation for mixed plate thicknesses and controls the upper limit of the time-averaged duty cycle of standing wave nodes. This solves the problems of single modes being unable to adapt to steel plates of different thicknesses and the long-standing standing wave blind zone, significantly improving the uniformity of the sound field in various areas of the hull and reducing local adhesion dead zones.

[0065] In one embodiment, the transducer may be any one or a combination of a piezoelectric ceramic transducer, an electromagnetic acoustic transducer, or a magnetostrictive transducer. The Lamb wave operates in the frequency range of 15-80kHz, and the microscopic cavitation effect induced by the excited Lamb wave on the water-side surface acts on the early attachment stage of marine organisms.

[0066] A piezoelectric ceramic transducer is a transducer element that achieves electroacoustic conversion by relying on the piezoelectric effect of piezoelectric ceramic crystals. A small amount of coupling agent is required when bonding it to a steel plate.

[0067] Electromagnetic acoustic transducers can be non-contact transducer structures with electromagnetic acoustic coupling, equipped with a bias magnetic field source and a high-frequency excitation coil. They do not require acoustic coupling agents and are suitable for long-term use in underwater vessels.

[0068] Magnetostrictive transducers are components that utilize the deformation of magnetostrictive materials to achieve electroacoustic conversion, and they are highly adaptable to high-power output scenarios.

[0069] Microscopic cavitation effect can be the physical effect of Lamb waves propagating to the seawater interface, generating and bursting tiny bubbles. The bursting of these bubbles generates micro-impacts that damage the biofilm initially attached to marine organisms.

[0070] The early attachment stage of marine organisms can be the initial stage of marine spores and microorganisms forming biofilms, before they have developed into macroscopic attachment organisms such as algae and shellfish.

[0071] This solution allows for the selection of a single type of transducer unit based on the ship's maintenance needs. For example, electromagnetic acoustic transducers can be used for long-haul ocean-going vessels, piezoelectric ceramic transducers for small inland waterway vessels, and a combination of two types of transducer units can be used for large container ships. The main control unit limits all modal excitation frequencies to the 15kHz to 80kHz range. Lamb waves in this frequency band can continuously generate microcavitation at the interface between the steel plate and seawater, prematurely destroying the substrate for microbial attachment and preventing marine organism colonization at its source.

[0072] This technical solution provides three types of interchangeable and combinable transducer hardware solutions to adapt to different ship operation and maintenance scenarios; it limits the dedicated operating frequency band to 15-80kHz and uses microscopic cavitation to suppress biofilm formation from the source, which significantly reduces the risk of steel plate corrosion compared with high-frequency strong ultrasound, while taking into account both antifouling effect and ship structural safety.

[0073] In one embodiment, optionally, the formula for calculating the contamination risk weighting coefficient λ is: ; Where t is the average plate thickness of the partition, v is the average flow velocity of the partition, d is the distance from any point in the partition to the nearest transducer unit, t, v, and d are dimensionless, and k1, k2, and k3 are preset weighting coefficients. The main control unit can prioritize each zone based on the value of λ, with zones having higher λ values ​​receiving priority allocation of antifouling resources. The fouling risk weighting coefficient λ can be a dimensionless value, taking into account three factors: board thickness, seawater flow velocity, and ultrasonic coverage distance. A higher value indicates a higher risk of marine organism attachment in that area.

[0074] The average plate thickness t of a zone can be the arithmetic mean of the thickness of all steel plates within the zone, in mm. The thinner the plate, the faster the Lamb wave attenuates, and the higher the risk.

[0075] The average flow velocity v of a zone can be the average velocity of seawater flow in the corresponding water area of ​​the zone, in m / s. The higher the flow velocity, the fewer plankton there are, and the lower the risk of attachment.

[0076] The distance d from any point within the partition to the nearest transducer unit can be the straight-line distance from the farthest point within the partition to the nearest transducer unit, in meters. The greater the distance, the greater the attenuation of ultrasonic energy and the weaker the anti-fouling effect.

[0077] The preset weighting coefficients k1, k2, and k3 can be fixed constants calibrated before leaving the factory, and can be adjusted according to the seawater environment of the navigation area. For example, the k2 flow velocity weight can be increased in highly polluted nearshore waters.

[0078] Anti-fouling resources can be system ultrasonic output resources such as drive unit output power, mode continuous excitation duration, and frequency switching frequency.

[0079] The main control unit calculates the λ values ​​of all partitions in real time and sorts them into priority queues from largest to smallest. System power resources are given priority to partitions with high λ values. For example, if the total power of the ship is limited, high-risk partitions will maintain full power operation, while low-risk partitions will reduce their output power.

[0080] This technical solution establishes a multi-dimensional quantitative fouling risk calculation model, eliminating the need for manual experience to prioritize protection. The system automatically allocates limited ultrasonic power resources, obtaining more ultrasonic energy in high-adhesion-risk areas, thus achieving intelligent tilting allocation of anti-fouling resources and improving the overall anti-fouling effect under the same power consumption of the whole machine.

[0081] In one embodiment, optionally, step 4, which involves dynamically adjusting the ship's navigation conditions, specifically includes: When the ship's speed vs < 3kn, only the high-pollution-risk zone with λ ≥ 0.7 is activated, the transducer unit is controlled to operate with a single frequency and low duty cycle, and the ultrasonic transmitting unit is turned off. When 3kn≤vs<12kn, all partitions are enabled, and high-risk contamination partitions use the A0 and S0 superimposed mode, while low-risk partitions use the S0 mode. When vs≥12kn, the high-fouling-risk zone is controlled to maintain A0 mode, while the medium- and low-risk zone switches to S0 mode, and the operating power decreases linearly with the increase of speed.

[0082] Ship speed (vs) can refer to the speed of a ship relative to the seawater, measured in knots (kn), where 1 knot = 1 nautical mile per hour.

[0083] Single-frequency low duty cycle can be a low-power operation mode that outputs only a single fixed frequency Lamb wave and has an excitation time of less than 20% per unit time.

[0084] The propeller rotation cycle, measured in seconds, is the time it takes for the propeller to complete one full rotation. It is used to control the trigger interval of the tail-launch unit.

[0085] During the ship's anchoring and low-speed drifting phases, seawater exchange is slow, and only high-risk zones activate low-power ultrasonic waves. The stern propeller and rudder experience gentle water flow, eliminating the need for directional cavitation, and the transmitting units are completely shut down to reduce energy consumption. During low-speed navigation in and out of port, the entire ship is protected synchronously. In high-risk areas, dual-modal superposition enhances the sound field, triggering stern ultrasonic waves once every half-rotation, balancing anti-fouling and power consumption. During high-speed ocean voyages, water flow naturally inhibits fouling, and low- and medium-risk zones reduce power consumption for energy saving. High-speed water flow exacerbates propeller fouling, so the trigger interval of the transmitting units is shortened, outputting ultrasonic waves once every 1 / 4 rotation.

[0086] This technical solution divides the ship into three differentiated operation strategies based on its speed. The low speed when moored, the medium speed when sailing, and the high speed when sailing at sea are matched with corresponding modes, power and tail launch timing. The higher the sailing speed, the lower the overall power consumption, which greatly reduces the power consumption of the ship during long-term operation and achieves graded energy-saving control.

[0087] In one embodiment, optionally, the optical path component in step 3 includes a light-transmitting window and a coupling lens disposed at the center of the transducer unit. The illumination light passes through the outer plate and illuminates the water-side surface. The reflected light returns along the original path and is received by the image sensor. The main control unit identifies the dirt coverage rate through an image processing algorithm. The electrical feedback signal includes the impedance amplitude, phase, and resonant frequency offset of the transducer unit.

[0088] The light-transmitting window can be a high-transmittance sealed glass structure built into the optical path component, fixed in the center of the transducer unit, sealing and isolating the air and seawater inside the cabin, while ensuring that light can penetrate the steel plate.

[0089] A coupling lens can be a focusing optical lens in the optical path to concentrate the illumination light and improve the image clarity of the water-side surface.

[0090] The illumination light can be visible light emitted by the LED light source built into the component or infrared detection light.

[0091] The image sensor, which can be a CMOS image acquisition chip, receives reflected light from the water side and converts it into a digital image, which is then transmitted to the main control unit.

[0092] The image processing algorithm can be an image grayscale segmentation algorithm built into the main control unit, which can distinguish between clean steel plate areas and areas where marine organisms are attached, and automatically calculate the proportion of the attached area.

[0093] The resonant frequency offset can be the difference between the actual resonant frequency of a component and its nominal resonant frequency at the factory. Scale buildup on the steel plate and mode switching can both cause this offset.

[0094] The LED light source emits illumination light, which passes through the light-transmitting window and steel plate to reach the seawater side. The light reflected by marine life and the steel plate is reflected back along the same path and converges to the image sensor through a coupling lens. The main control unit reads the image and calculates the dirt coverage rate through grayscale threshold segmentation. The drive unit's acquisition circuit simultaneously captures three sets of electrical data: impedance amplitude, current-voltage phase difference, and real-time resonant frequency, which are combined as a complete electrical feedback signal and uploaded to the main control unit.

[0095] This technical solution clarifies the composition of optical monitoring hardware and the imaging detection process, while improving the electrical feedback acquisition indicators. The dual-channel monitoring data is comprehensive and can accurately identify the degree of marine organism attachment and simultaneously determine the resonant matching state of the transducer unit, providing sufficient and reliable raw data support for subsequent modal parameter correction.

[0096] In one embodiment, optionally, step 4 of correcting the Lamb wave mode parameters includes: Based on the preset interval level into which the fouling coverage falls, a correction parameter corresponding to the preset interval level is determined, and the wave parameters of the current mode are dynamically corrected based on the correction parameter.

[0097] This could be a correction of parameters such as wavelength and frequency of the Lamb wave in the current mode.

[0098] In another feasible approach, the S0 mode can be preferred when the contamination coverage is less than 5%. When the contamination coverage is ≥5% and <30%, switch to the superposition mode of A0 and S0, and increase the duty cycle to 30%-50%; When the contamination coverage is ≥30%, switch to A0 mode and briefly increase the power to 120% of the rated power to perform the stripping operation; When the impedance value of the electrical feedback deviates from the nominal value by more than 15%, the current operating frequency is automatically fine-tuned to achieve impedance matching.

[0099] Rated power can be the standard safe output power specified by the manufacturer for the transducer unit. Short-term 120% power is only used for heavy-duty decontamination stripping and the duration shall not exceed 10 minutes.

[0100] The nominal value can be the standard impedance value of the transducer unit under no-load and no-scaling conditions at the factory.

[0101] Impedance matching can be achieved by fine-tuning the excitation frequency to make the output impedance of the drive unit nearly identical to the input impedance of the transducer element, thereby reducing power transmission loss.

[0102] The stripping operation can be carried out using short-term high-power ultrasonic enhanced cavitation effect to strip off algae and shellfish attachments that have already formed on the surface of the steel plate.

[0103] The partition contains only trace amounts of biofilm, and the S0 mode has lower energy consumption, meeting the basic requirements for adhesion inhibition.

[0104] The main control unit compares the measured impedance with the nominal impedance in real time. When the deviation exceeds 15%, it slightly adjusts the excitation frequency to complete dynamic impedance matching and reduce energy loss.

[0105] This technical solution employs a three-level modal control strategy based on the fouling coverage rate. Light, moderate, and heavy fouling are matched with corresponding modes and output intensities, respectively. Simultaneously, the operating frequency is automatically calibrated based on impedance deviation, achieving integrated adaptive fouling control and hardware impedance self-correction, thus balancing the anti-fouling effect with the energy utilization efficiency of the equipment.

[0106] In one embodiment, optionally, the excitation timing of the ultrasonic transmitting unit in step 4 is subjected to propeller-axis synchronous phase modulation: The main control unit receives the propeller shaft angular position sensor signal and outputs the excitation pulse only within the 120° phase window when the blade rotates to the front of the transmitting unit. It also controls the sound pressure level to be within the adhesion suppression and non-erosion window of 140-150 dB re 1μPa @1m to avoid continuous cavitation erosion on the same blade.

[0107] Propeller shaft synchronous phase modulation can be achieved through propeller shaft synchronous control logic, which binds the ultrasonic emission timing to the propeller rotation angle and outputs ultrasonic waves intermittently according to the propeller blade phase window.

[0108] A shaft angle position sensor can be an angle acquisition device installed at the end of a propeller drive shaft, which outputs a rotation angle signal from 0° to 360° in real time.

[0109] The phase window can be the angular range in which the propeller blades are fully exposed to the ultrasonic radiation range of the transmitting unit; this scheme limits it to 120°.

[0110] The excitation pulse can be a high-frequency ultrasonic electrical signal that drives the ultrasonic transmitting unit to output for a short period of time.

[0111] Sound pressure level can be an indicator of the pressure intensity of underwater ultrasound, measured in dB (decibels).

[0112] The adhesion-inhibiting and corrosion-free window can be a safe sound pressure range, which can both inhibit marine organism adhesion and be below the cavitation corrosion threshold of metal blades.

[0113] Continuous cavitation erosion can occur when a single blade is subjected to ultrasonic cavitation impacts over a long period of time, causing pitting corrosion and fatigue damage to the blade surface.

[0114] The main control unit reads the propeller shaft angle signal in real time and only outputs an ultrasonic pulse to the tail-end transmitting unit when the propeller blade rotates into the 120° aligned range; the excitation is cut off in other angle ranges. The drive unit adjusts the output power of the transmitting unit in real time to stably control the underwater cavitation field sound pressure within the range of 140 to 150 decibels, thus protecting the metal substrate of the propeller blade while achieving antifouling.

[0115] This technical solution employs synchronous phase modulation of the propeller shaft angle to emit ultrasound only through the exposed window of the propeller blade, thus avoiding continuous cavitation corrosion of a single blade. It also limits a dedicated safe sound pressure range, balancing the anti-fouling effect of the propeller rudder with the service life of the propeller structure, and solving the defect of continuous radiation from existing tail-end ultrasonic equipment that causes blade corrosion damage.

[0116] In one embodiment, step 4 may optionally include a standing wave node time-shift avoidance strategy: The main control unit controls the transducer unit to cyclically switch between at least 3 different frequency points, with the frequency difference Δf between adjacent frequency points being ≥2kHz, so that the position offset of the standing wave node corresponding to the adjacent frequency point is ≥50mm.

[0117] Standing wave node time shift avoidance strategy can be a frequency rotation optimization scheme, which changes the distribution of standing wave nodes by cyclically switching multiple frequencies, reducing the probability that the nodes are in the blind zone for a long time.

[0118] Among them, the frequency point can be a fixed operating frequency for stable excitation by the Lamb wave, and the same set of transducer units can store multiple independent frequency points.

[0119] The frequency difference Δf can be the numerical interval between two sets of cyclic frequency points, with a minimum of 2kHz.

[0120] The node position offset can be the straight-line distance between two sets of standing wave nodes generated at different frequencies on the steel plate surface, with a minimum offset of 50mm.

[0121] The main control unit stores three or more working frequency points adapted to the current mode and switches the output in a fixed cycle; the frequency point interval is not less than 2kHz, ensuring that the standing wave node generated by each set of frequency points is staggered by at least 50 mm from the previous set, eliminating fixed blind spots.

[0122] This technical solution achieves dynamic displacement of standing wave nodes by rotating multiple frequency points and limiting the minimum frequency difference and node offset distance. This significantly reduces the probability that any point will be in a long-term ultrasonic blind zone. Combined with the weighted 2 node time-averaged duty cycle control, it completely solves the problem of local marine organism attachment caused by the standing wave blind zone of the steel plate, and further improves the antifouling uniformity of the entire plate surface.

[0123] To help technical personnel better understand this solution, a specific implementation method is also provided.

[0124] Figure 2 This is a schematic diagram of the antifouling method based on Lamb wave multimodal combination provided in an embodiment of this application. Figure 2 As shown: S1: Install the transducer unit on the inner surface of the outer panel; S2: Excites Lamb wave (A0+S0 mode combination); The main control unit controls the transducer unit to excite Lamb waves inside the outer plate. The excited waveform contains at least a combination of A0 mode and S0 mode. Figure 2 The criteria for modality selection are clearly given in the key rule box on the right: Board thickness <15mm → A0 preferred (frequency-thickness product 0.1–0.6 MHz·mm); Board thickness ≥ 15mm → S0 preferred (frequency-thickness product 0.5–1.5 MHz·mm); Mixed plate thickness → A0 / S0 time reuse; Alternating excitation with complementary duty cycle coverage; Transducer types: piezoelectric / electromagnetic / magnetostrictive; Switching triggers: speed / fouling / electrical feedback; Coverage radius ≥15m; Operating frequency 15–80kHz.

[0125] S3: Forms an anti-pollution acoustic field (microscopic cavitation); The above-mentioned modal combination creates an acoustic field that is unfavorable to marine organism attachment near the outer plate and waterside surface, and utilizes the microscopic cavitation effect to act on the early attachment stage of marine organisms.

[0126] S4: Dynamically switch modes based on plate thickness, structure, and contamination feedback.

[0127] Based on the plate thickness distribution, reinforcement structure features, or pollution feedback status of the area to be protected, the main control unit automatically makes a decision at the "modal selection" node and switches to one of three outputs: A0 mode, superimposed mode, or S0 mode.

[0128] The switching process can be triggered by real-time navigation status, fouling sensor feedback or transducer unit electrical feedback signal, and by alternately exciting A0 and S0 according to a preset duty cycle, the spatial action field can be complementary and cover each other, and the node time-averaged duty cycle of any spatial point can be controlled within a preset threshold.

[0129] This solution effectively eliminates the standing wave blind zone caused by the hull reinforcement structure through zoned differentiated modal matching and dual-source feedback self-correction, achieving uniform coverage of the antifouling field across the entire ship. By dynamically scheduling power and duty cycle in conjunction with navigation conditions such as speed and RPM, it significantly reduces the overall energy consumption of the ship while ensuring antifouling effectiveness in high-fouling areas. Combined with closed-loop control of optical fouling monitoring and electrical impedance feedback, it can adaptively match the optimal modal parameters without manual intervention and precisely limit the sound pressure within the anti-attachment and non-corrosion window, balancing antifouling effect and hull structural safety. The overall antifouling efficiency is improved by more than 40%, and energy consumption is reduced by more than 30%.

[0130] Example 2 Figure 3 This is a schematic diagram of the structure of the Lamb wave-based ultrasonic antifouling device for ships provided in this application embodiment. Figure 3 As shown, the device includes: The protection zone determination module 301 is used to divide the underwater outer plate of the ship into multiple protection zones, and to install transducer units on the inner surface of each zone, as well as ultrasonic transmitting units. The modal parameter determination module 302 is used to pre-store the plate thickness parameters, contamination risk weight coefficients and suitable Lamb wave modal parameters corresponding to each protection zone. The Lamb wave modal parameters include at least the A0 mode, the S0 mode, and the frequency-thickness product and duty cycle of their superimposed modes. The dual-source feedback data acquisition module 303 is used to collect the fouling coverage rate of the water-side surface of each zone and obtain the real-time impedance value through the electrical feedback signal of the transducer unit to form dual-source feedback data. The modal parameter correction module 304 is used to correct the Lamb wave modal parameters of each zone according to the dual-source feedback data, and dynamically adjust the working power, duty cycle and excitation timing of the ultrasonic transmitting unit of each zone in conjunction with the current navigation conditions of the ship. The anti-fouling sound field construction module 305 is used to generate modified Lamb waves within the outer plate through the transducer unit, forming an anti-fouling sound field covering the hull surface.

[0131] The Lamb wave-based ultrasonic antifouling device for ships provided in this application can realize the various processes of the above embodiments, and will not be repeated here to avoid repetition.

[0132] Example 3 This application also provides an electronic device, including a processor, a memory, and a program or instructions stored in the memory and executable on the processor. When the program or instructions are executed by the processor, they implement the various processes of the above-described embodiments of the Lamb wave-based ship ultrasonic antifouling method and achieve the same technical effect. To avoid repetition, these will not be described again here.

[0133] It should be noted that the electronic devices in the embodiments of this application include mobile electronic devices and non-mobile electronic devices as described above.

[0134] Example 4 This application also provides a readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various processes of the above-described embodiments of the ultrasonic antifouling method for ships based on Lamb waves and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0135] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0136] Example 5 This application also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described embodiments of the ship ultrasonic antifouling method based on Lamb waves, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0137] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0138] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element. Furthermore, it should be noted that the scope of the methods and systems in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0139] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0140] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0141] The above description is merely a preferred embodiment and the technical principles employed in this application. This application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions that can be made by those skilled in the art will not depart from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of this application, the scope of which is determined by the scope of the claims.

Claims

1. A method for ultrasonic antifouling of ships based on Lamb waves, characterized in that, The method includes: Step 1: Divide the underwater outer plating of the ship into multiple protective zones, and install transducer units and ultrasonic transmitting units on the inner surface of each zone. Step 2: Pre-store the plate thickness parameters, contamination risk weight coefficients and suitable Lamb wave mode parameters corresponding to each protection zone. The Lamb wave mode parameters include at least the frequency-thickness product and duty cycle of the A0 mode, S0 mode and their superposition modes. Step 3: Collect the fouling coverage rate of the water-side surface of each zone, and obtain the real-time impedance value through the electrical feedback signal of the transducer unit to form dual-source feedback data; Step 4: Correct the Lamb wave mode parameters of each zone based on the dual-source feedback data, and dynamically adjust the working power, duty cycle of the transducer unit of each zone and the excitation timing of the ultrasonic transmitting unit in conjunction with the current navigation conditions of the ship. Step 5: The modified Lamb wave is excited inside the outer plate through the transducer unit to form an anti-fouling sound field covering the surface of the hull.

2. The method according to claim 1, characterized in that, The division of the protection zones is based on the hull location, plate thickness, and reinforcement structure features, and is at least divided into the bow zone, side zone, bottom zone, and propeller and rudder zone. The selection of the Lamb wave mode parameters satisfies at least one of the following conditions: When the thickness of the protective partition plate is less than 15mm, the A0 mode with a frequency-thickness product in the range of 0.1-0.6MHz·mm is preferred. When the thickness of the protective partition plate is not less than 15mm, the S0 mode with a frequency-thickness product in the range of 0.5-1.5MHz·mm is preferred. When the protection zone contains a mixed distribution of plate thickness, time-multiplexed excitation of A0 mode and S0 mode is used; The A0 mode and the S0 mode are alternately excited with a preset duty cycle, so that their spatial interaction fields form a complementary coverage, and the time-averaged duty cycle of the node state at any spatial point of the outer plate does not exceed 15%.

3. The method according to claim 1, characterized in that, The transducer unit is any one or more combinations of piezoelectric ceramic transducer, electromagnetic acoustic transducer or magnetostrictive transducer. The Lamb wave operates in the frequency range of 15-80kHz, and the microscopic cavitation effect induced by the excited Lamb wave on the water-side surface acts on the early attachment stage of marine organisms.

4. The method according to claim 1, characterized in that, The formula for calculating the contamination risk weighting coefficient λ is as follows: ； Where t is the average plate thickness of the partition, v is the average flow velocity of the partition, d is the distance from any point in the partition to the nearest transducer unit, t, v, and d are dimensionless, and k1, k2, and k3 are preset weighting coefficients. The main control unit prioritizes each partition based on the value of λ, with partitions having higher λ values ​​receiving priority allocation of antifouling resources.

5. The method according to claim 4, characterized in that, The dynamic adjustment of the ship's navigation conditions in step 4 specifically includes: When the ship's speed vs < 3kn, only the high-pollution-risk zone with λ ≥ 0.7 is activated, the transducer unit is controlled to operate with a single frequency and low duty cycle, and the ultrasonic transmitting unit is turned off. When 3kn≤vs<12kn, all partitions are enabled, and high-risk contamination partitions use the A0 and S0 superimposed mode, while low-risk partitions use the S0 mode. When vs≥12kn, the high-fouling-risk zone is controlled to maintain A0 mode, while the medium- and low-risk zone switches to S0 mode and the operating power decreases linearly with the increase of speed.

6. The method according to claim 1, characterized in that, In step 3, the fouling coverage rate of the water-side surface of each zone is collected, including acquiring image data of the water-side surface. The main control unit identifies the fouling coverage rate through image processing algorithms.

7. The method according to claim 6, characterized in that, The step 4 of correcting the Lamb wave mode parameters includes: Based on the preset interval level into which the fouling coverage falls, a correction parameter corresponding to the preset interval level is determined, and the wave parameters of the current mode are dynamically corrected based on the correction parameter.

8. The method according to claim 1, characterized in that, Step 4 also includes a standing wave node time-shift avoidance strategy: The main control unit controls the transducer unit to cyclically switch between at least 3 different frequency points, with the frequency difference Δf between adjacent frequency points being ≥2kHz, so that the position offset of the standing wave node corresponding to the adjacent frequency point is ≥50mm.

9. A marine ultrasonic antifouling device based on Lamb waves, characterized in that, The device includes: The protection zone determination module is used to divide the underwater outer plate of the ship into multiple protection zones, and to install transducer units on the inner surface of each zone, as well as ultrasonic transmitting units. The modal parameter determination module is used to pre-store the plate thickness parameters, contamination risk weight coefficients and suitable Lamb wave modal parameters corresponding to each protection zone. The Lamb wave modal parameters include at least the A0 mode, the S0 mode, and the frequency-thickness product and duty cycle of their superimposed modes. The dual-source feedback data acquisition module is used to collect the fouling coverage rate of the water-side surface of each zone and obtain the real-time impedance value through the electrical feedback signal of the transducer unit to form dual-source feedback data. The modal parameter correction module is used to correct the Lamb wave modal parameters of each zone according to the dual-source feedback data, and dynamically adjust the working power, duty cycle and excitation timing of the ultrasonic transmitting unit of each zone in conjunction with the current navigation conditions of the ship. The anti-fouling sound field construction module is used to generate modified Lamb waves within the outer plate through the transducer unit, forming an anti-fouling sound field covering the hull surface.

10. An electronic device, characterized in that, The electronic device includes a processor, a memory, and a program or instructions stored in the memory and executable on the processor, wherein the program or instructions, when executed by the processor, implement the steps of the method as described in any one of claims 1-8.

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