Underwater spherical object detection method and device based on underwater carrier

Abstract

The invention provides an underwater spherical object detection method and device based on an underwater carrier. The method comprises the steps that an underwater carrier carries an electric field emission module and an electrode receiving array to maneuver underwater, the electric field emission module releases extremely low frequency alternating current into water, and a specifically distributed electric field is formed in a target area; the electrode receiving array is used for measuring space electric field signals in real time and acquiring electric signal amplitudes of multiple paths of measuring electrodes relative to the reference electrode; processing the amplitude of the electric signal, calculating the variable quantity of the electric signal relative to the initial state, and judging whether a target exists or not and the relative distance and orientation of the target according to the extreme value change and distribution characteristics of the variable quantity; a control signal is generated based on the judgment result, and the movement direction and speed of the underwater carrier are adjusted to be close to a target; and after approaching the target, carrying out video and image discrimination, if the target is not the target, searching again, and if the target is the target, giving an alarm. According to the invention, the detection efficiency and accuracy can be effectively improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of underwater spherical object positioning, and in particular, to a method and device for detecting underwater spherical objects based on an underwater vehicle. Background Art

[0002] Currently, acoustic detection means and optical detection means are mostly used for detecting underwater spherical objects. However, in the shallow sea area, the effectiveness of traditional detection means will decline, or even completely fail. Due to the complex seabed topography, numerous obstacles, and rapidly changing ocean currents in the shallow sea area, serious reflection, refraction, scattering and other phenomena of acoustic signals occur, and multipath interference is severe, affecting the detection effect of sonar. At the same time, the water quality in the shallow sea is poor, and there are turbid waters with plankton, sediment, impurities, etc., seriously affecting the detection efficiency and accuracy of optical detection means. Therefore, developing a method and device for detecting underwater spherical objects based on an underwater vehicle to effectively overcome the defects in the above related technologies has become an urgent technical problem in the industry. Summary of the Invention

[0003] In view of the above problems existing in the prior art, the embodiments of the present invention provide a method and device for detecting underwater spherical objects based on an underwater vehicle.

[0004] In a first aspect, the embodiments of the present invention provide a method for detecting underwater spherical objects based on an underwater vehicle, including: the underwater vehicle is maneuvered underwater with an electric field emission module and an electrode receiving array. The electric field emission module releases an extremely low-frequency alternating current into the water to form an electric field with a specific distribution in the target area. The electrode receiving array measures the spatial electric field signal in real time to obtain the electrical signal amplitude U of multiple measurement electrodes relative to the reference electrode. The electrical signal amplitude U is processed to calculate its change amount △U relative to the initial state. According to the extreme value change and distribution characteristics of the change amount △U, it is judged whether the target exists, the relative distance and azimuth of the target. Based on the judgment result, a control signal is generated to adjust the movement direction and speed of the underwater vehicle to approach the target. After approaching the target, after video and image discrimination, if it is not the target, re-search is performed, and if it is the target, an alarm is issued.

[0005] Based on the content of the above method embodiment, in the method for detecting underwater spherical objects based on an underwater vehicle provided in the embodiments of the present invention, the frequency of the extremely low-frequency alternating current is 10 Hz to 30 Hz, and the current intensity is set according to the detection environment and target characteristics. The electric field emission module includes a pair of metal electrodes arranged along the longitudinal or transverse axis of the underwater vehicle, and the metal electrodes are platinum metal sheets or titanium plates plated with ruthenium iridium on the outer layer.

[0006] Based on the content of the above method embodiments, the underwater spherical object detection method based on an underwater vehicle provided in the embodiments of the present invention, wherein the electrode receiving array is in an "X" shape, includes: a reference electrode located at the intersection of the "X", and four measuring electrodes symmetrically distributed at the ends of the four arms of the "X". All the reference electrodes and all the measuring electrodes are silver or silver chloride solid electrodes.

[0007] Based on the content of the above method embodiments, the underwater spherical object detection method based on an underwater vehicle provided in the embodiments of the present invention, the processing of the amplitude U of the electrical signal includes: calculating the change amount △U relative to its initial state, setting a threshold △Uthr, and when the change amount △U is greater than the threshold △Uthr and a maximum value △Umax appears, determining the existence of a target; by comparing the change amount △U values of the four measuring electrodes, determining that the target is on the side of the electrode with a larger change amount △U value; and determining the change in the distance between the target and the underwater vehicle according to the change in the magnitude of the maximum value △Umax of the change amount △U.

[0008] Based on the content of the above method embodiments, the underwater spherical object detection method based on an underwater vehicle provided in the embodiments of the present invention, generating a control signal based on the judgment result to adjust the movement direction and speed of the underwater vehicle to approach the target includes: the underwater vehicle maneuvers back and forth along a preset "S" - shaped trajectory to cover the search area, and confirms the existence of the target according to the characteristics of the change amount △U in single - or multiple - cruises; when the change amount △U is greater than the threshold △Uthr and a maximum value △Umax appears, controlling the vehicle to turn, and continuously adjusting the direction through a closed - loop feedback mechanism until approaching the target.

[0009] Based on the content of the above method embodiments, the underwater spherical object detection method based on an underwater vehicle provided in the embodiments of the present invention, all the reference electrodes and all the measuring electrodes are fixed on the underwater vehicle through hollow insulating tubes, and the electrode signal lines are collected into the watertight space of the vehicle through the hollow insulating tubes. The arm lengths and included angles of the "X" - shaped electrode receiving array are adjusted according to the detection requirements to ensure that the electrode plane is parallel to the horizontal plane.

[0010] In a second aspect, an embodiment of the present invention provides an underwater spherical object detection system based on an underwater vehicle, including: an underwater vehicle for carrying a detection device to achieve controllable underwater movement; an electric - field emission module for releasing an extremely - low - frequency alternating current into the water to apply an electric - field signal with a specific distribution in the sea area; an electrode receiving array for measuring the spatial electric - field signal in the underwater environment; and a signal processing and control module for loading a corresponding program to implement the underwater spherical object detection method based on an underwater vehicle as described in any of the foregoing method embodiments.

[0011] In a third aspect, an embodiment of the present invention provides an underwater spherical object detection device based on an underwater vehicle, including: a first main module for enabling the underwater vehicle to carry an electric field emission module and an electrode receiving array to maneuver underwater, where the electric field emission module releases an extremely low frequency alternating current into the water to form an electric field with a specific distribution in the target area; a second main module for enabling the electrode receiving array to measure the spatial electric field signal in real time and obtain the electric signal amplitude U of multiple measurement electrodes relative to the reference electrode; a third main module for processing the electric signal amplitude U, calculating its change amount △U relative to the initial state, and judging the existence of the target, the relative distance and azimuth of the target according to the extreme value change and distribution characteristics of the change amount △U; a fourth main module for generating a control signal based on the judgment result and adjusting the movement direction and speed of the underwater vehicle to approach the target; a fifth main module for, after approaching the target, performing video and image discrimination, and if it is not the target, re-searching, and if it is the target, issuing an alarm.

[0012] In a fourth aspect, an embodiment of the present invention provides an electronic device, including:

[0013] at least one processor, at least one memory, and a communication interface; wherein,

[0014] the processor, the memory, and the communication interface communicate with each other;

[0015] the memory stores program instructions executable by the processor, and the processor calls the program instructions to execute the underwater spherical object detection method based on an underwater vehicle provided by any one of the various implementation manners of the first aspect.

[0016] In a fifth aspect, an embodiment of the present invention provides a non-transitory computer-readable storage medium, and the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions cause the computer to execute the underwater spherical object detection method based on an underwater vehicle provided by any one of the various implementation manners of the first aspect.

[0017] The underwater spherical object detection method and device based on an underwater vehicle provided by the embodiments of the present invention significantly enhance the detection ability of new type of concealed underwater spherical objects by adopting active electric field detection means, and can be used as an effective supplement to sound, light, and magnetic detection technologies; it has strong environmental adaptability, can still stably detect in complex environments such as turbid water quality and no light at night, and the cost of the required electrodes and emission modules is relatively low. By real-time monitoring of the change of the electric signal, it can accurately locate the azimuth and distance of the target, effectively improving the detection efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 Schematic flow chart of the underwater spherical object detection method based on an underwater vehicle provided by an embodiment of the present invention;

[0020] Figure 2 Schematic structural diagram of the underwater spherical object detection device based on an underwater vehicle provided by an embodiment of the present invention;

[0021] Figure 3 Schematic physical structure diagram of the electronic device provided by an embodiment of the present invention;

[0022] Figure 4 Schematic structural diagram of the underwater spherical object detection system based on an underwater vehicle provided by an embodiment of the present invention;

[0023] Figure 5 Schematic diagram of the detection operation effect of the device based on Ansys Maxwell software provided by an embodiment of the present invention;

[0024] Figure 6 Schematic diagram of the △U effect measured by each detection electrode when the target exists provided by an embodiment of the present invention;

[0025] Figure 7 Schematic diagram of the △U effect measured by the detection electrode when the vehicle moves along the E1, E2, and E3 trajectories with the target fixed provided by an embodiment of the present invention;

[0026] Figure 8 Schematic diagram of the target observation index effect provided by an embodiment of the present invention;

[0027] Figure 9 Schematic diagram of the influence of the target lateral distance on the observable range under two different thresholds provided by an embodiment of the present invention;

[0028] Figure 10 Schematic diagram of the influence of the target lateral distance on the earliest warning distance under two different thresholds provided by an embodiment of the present invention;

[0029] Figure 11 Schematic diagram of the influence of the target radius on the maximum detection distance provided by an embodiment of the present invention;

[0030] Figure 12 Schematic diagram of the maximum detectable distance of each current intensity under two thresholds provided by an embodiment of the present invention;

[0031] Figure 13 Schematic diagram of the specific structure of the detection system experimental model provided by the embodiment of the present invention;

[0032] Figure 14 Schematic diagram of the physical object and parameters of the detection system model provided by the embodiment of the present invention;

[0033] Figure 15 Schematic diagram of the experimental layout effect provided by the embodiment of the present invention;

[0034] Figure 16 Schematic diagram of the measurement and simulation results of the measurement electrodes on the experimental model for different target disturbance amounts provided by the embodiment of the present invention;

[0035] Figure 17 Schematic diagram of the measurement and simulation results of the same target disturbance amount under different motion trajectories provided by the embodiment of the present invention. Specific implementation manners

[0036] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. In addition, the technical features in each embodiment or individual embodiment provided by the present invention can be combined with each other arbitrarily to form a feasible technical solution. Such combination is not restricted by the order of steps and / or the mode of structural composition, but must be based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the protection scope required by the present invention. If there are step numbers in the following embodiments, they are only set for the convenience of explanation and illustration, and no limitation is imposed on the order between steps. The execution order of each step in the embodiments can be adjusted adaptively according to the understanding of those skilled in the art.

[0037] Research findings show that when an underwater spherical object enters a space with an electric field distribution, due to its electromagnetic properties of the material, the electric field distribution around it will be distorted, resulting in changes in the electric field signal magnitudes at each field point. These changes in the electric field signal can be detected by electrodes. By analyzing these changes through a pre-set signal processing module, the position, size, shape, and other physical properties of the target can be inferred. Based on this characteristic phenomenon, researchers actively apply an electric field underwater and use detectors to sense the distortion of the electric field to discover and locate the target. This technology is called active electric field detection technology. With the continuous development of this technology, it has been applied and studied in the fields of object imaging, defect detection, positioning, navigation, tracking, environmental detection, biological detection, etc. The structural characteristics of underwater spherical objects will also cause disturbances in the underwater current field. Some researchers have carried out theoretical derivations, simulation calculations, and model experimental studies on its disturbance mechanism and characteristics. These research results provide a reference for the application of the active electric field detection technology for actual underwater spherical objects. And with the continuous development of the underwater active electric field detection technology, its significant advantages are expected to become a useful supplement to traditional detection technology means. Based on this, the embodiments of the present invention provide a method for detecting underwater spherical objects based on an underwater vehicle, see Figure 1 , the method includes: the underwater vehicle carries an electric field emission module and an electrode receiving array to maneuver underwater. The electric field emission module releases an extremely low-frequency alternating current into the water to form an electric field with a specific distribution in the target area; the electrode receiving array measures the spatial electric field signal in real time to obtain the electric signal amplitude U of multiple measurement electrodes relative to the reference electrode; process the electric signal amplitude U, calculate its change amount △U relative to the initial state, and judge whether the target exists, the relative distance and azimuth of the target according to the extreme value change and distribution characteristics of the change amount △U; generate a control signal based on the judgment result to adjust the movement direction and speed of the underwater vehicle to approach the target; after approaching the target, after video and image discrimination, if it is not the target, search again, if it is the target, issue an alarm.

[0038] Specifically, when the equipment enters the preparation stage, the electric field emission module is powered on to work, and an extremely low-frequency alternating current is applied across the metal electrodes. After the current of the electric field emission module stabilizes, the vehicle starts to maneuver according to the search plan, and the electrode receiving array records U1, U2, U3, and U4 after the movement of the device. The signal processing and control module processes the measurement data in real time to obtain the change conditions of △U1, △U2, △U3, and △U4, and sets the thresholds △Uthr to 5mV and 3mV in two levels according to the sea area environment and mission requirements. When △U (specifically any one of △U1, △U2, △U3, and △U4, the same below) is greater than the threshold △Uthr, it is regarded as the appearance of a suspected target, and the vehicle will change the target search strategy and calibrate the position of the suspected target; when △U is less than the threshold △Uthr, it is regarded as no target around, and the vehicle continues to drive according to the planned route. The vehicle approaches the target according to the positioning information. After video and image recognition, if it is not an underwater spherical object, it will search again according to the original plan. If it is an underwater spherical object, an alarm will be issued.

[0039] Based on the content of the above method embodiments, as an alternative embodiment, in the underwater spherical object detection method based on an underwater vehicle provided in the embodiments of the present invention, the frequency of the extremely low-frequency alternating current is 10 Hz to 30 Hz, and the current intensity is set according to the detection environment and target characteristics. The electric field emission module includes a pair of metal electrodes arranged along the longitudinal or transverse axis of the underwater vehicle, and the metal electrodes are platinum sheets or titanium plates with a ruthenium-iridium coating on the outer layer.

[0040] Based on the content of the above method embodiments, as an alternative embodiment, in the underwater spherical object detection method based on an underwater vehicle provided in the embodiments of the present invention, the electrode receiving array is in an "X" shape, including: a reference electrode located at the intersection of the "X", and four measurement electrodes symmetrically distributed at the ends of the four arms of the "X". All the reference electrodes and all the measurement electrodes are silver or silver chloride solid electrodes.

[0041] Specifically, the control feature refers to the position and phase azimuth information of the target obtained through the change amount △U of the amplitude of the 4-way spatial electric field relative to the initial state, including target appearance, target azimuth, and target distance information.

[0042] Based on the content of the above method embodiments, as an alternative embodiment, in the underwater spherical object detection method based on an underwater vehicle provided in the embodiments of the present invention, the processing of the electric signal amplitude U includes: calculating its change amount △U relative to the initial state, setting a threshold △Uthr, and when the change amount △U is greater than the threshold △Uthr and a maximum value △Umax appears, determining the existence of the target; by comparing the change amount △U values of the four measurement electrodes, determining that the target is located on the side of the electrode with a larger change amount △U value; and determining the change in the distance between the target and the underwater vehicle according to the change in the magnitude of the maximum value △Umax of the change amount △U.

[0043] Specifically, the method for judging the relative position of the target according to △U includes: setting a threshold △Uthr. During the movement of the detection device, when △U is greater than △Uthr and a maximum value △Umax appears, it can be judged that the target appears. During the movement of the detection device, if the △U value of the measurement electrode closer to the target side is greater than the △U value of the detection electrode farther from the target side, it can be judged that the target is on the side of the measurement electrode with a larger △U value. During the movement of the detection device, the change in the magnitude of △Umax corresponds to the change in the distance between the target and the detection device. The larger △Umax is, the closer the target is to the detection device.

[0044] Based on the content of the above method embodiment, as an optional embodiment, in the underwater spherical object detection method based on an underwater vehicle provided by the embodiments of the present invention, generating a control signal based on the judgment result and adjusting the movement direction and speed of the underwater vehicle to approach the target includes: the underwater vehicle maneuvers back and forth along a preset "S" - shaped trajectory to cover the search area, and confirms the existence of the target according to the characteristics of the change amount △U in a single or multiple cruises. When the change amount △U is greater than the threshold △Uthr and a maximum value △Umax appears, control the vehicle to turn, and continuously adjust the direction through a closed - loop feedback mechanism until approaching the target.

[0045] Specifically, the "S" - shaped scanning path planning. The underwater vehicle maneuvers back and forth horizontally along a preset "S" - shaped trajectory, and each trip covers a complete search area. When a characteristic signal is detected, an immediate alarm can be triggered, or after the end of a single cruise cycle, all the collected data can be integrated for in - depth analysis and judgment. This process requires multiple iterative searches and data comparison verifications until it is clear that there is a target on the horizontal vertical line of a specific track, then the existence of the target is officially confirmed. On the contrary, if no characteristic signal is obtained during a single round - trip maneuver, the underwater vehicle will enter the next scanning cruise cycle according to the preset program, and so on until the entire search area is thoroughly searched. The "S" - shaped scanning path planning is suitable for searching for targets with a small number and sparse distribution in a vast sea area. When the specific location of the target is unknown and a large area needs to be comprehensively scanned, the horizontal back - and - forth maneuver can provide fast and non - omissive search coverage.

[0046] Navigation homing path planning. During the maneuvering process of an underwater vehicle, if a characteristic signal exceeding the warning threshold and having a maximum change amount appears, the underwater vehicle is comprehensively judged based on the characteristic signal and guided to perform precise steering operations. After the steering action is executed, the relative azimuth between the vehicle and the target changes dynamically, thereby causing the control characteristics to change. When the control characteristics exceed the warning threshold again and the maximum change amount appears, the control algorithm is called again to implement a new round of steering control. The above process constitutes a closed-loop feedback mechanism, and the vehicle will continuously execute this series of actions, steering, detection, and re-steering until the distance between the vehicle and the target converges to a minimum value, thereby achieving precise search and positioning of the target. Navigation homing path planning is applicable to performing detection tasks when the approximate position of the target is known or in an area where the targets are densely distributed, can quickly approach the target, reduce the search time and energy consumption, and is relatively more efficient.

[0047] Based on the content of the above method embodiment, as an optional embodiment, in the underwater spherical object detection method based on an underwater vehicle provided in the embodiment of the present invention, all reference electrodes and all measurement electrodes are fixed on the underwater vehicle through a hollow insulating tube, and the electrode signal lines are gathered into the watertight space of the vehicle through the hollow insulating tube. The arm lengths and included angles of the "X"-shaped electrode receiving array are adjusted according to the detection requirements to ensure that the electrode plane is parallel to the horizontal plane.

[0048] The underwater spherical object detection method based on an underwater vehicle provided in the embodiment of the present invention significantly enhances the detection ability of new and concealed underwater spherical objects by adopting the active electric field detection means, and can be used as an effective supplement to acoustic, optical, and magnetic detection technologies; it has strong environmental adaptability and can still stably detect in complex environments such as turbid water quality and no light at night, and the cost of the required electrodes and emission modules is relatively low. By real-time monitoring the change of the electric signal, it can accurately locate the target azimuth and distance, effectively improving the detection efficiency and accuracy.

[0049] The underwater spherical object detection method based on an underwater vehicle provided in the embodiment of the present invention provides a new idea for the detection of underwater spherical objects and enriches the underwater detection technical means. At the same time, the present invention can also be used in various scenarios such as underwater target salvage, pipeline detection, marine resource exploration, and underwater search and rescue after appropriate modification, and has a wide range of industrial application prospects. Its significant technological progress solves the problem of poor adaptability of traditional detection technologies in complex underwater environments and provides an innovative solution for the detection of underwater spherical objects.

[0050] The underwater spherical object detection method based on an underwater vehicle provided by an embodiment of the present invention starts from the interaction mechanism and disturbance law between an underwater sphere and an active electric field, and realizes the active electric field detection of the underwater sphere by means of the movement of the vehicle. The detection idea adopted is to use control features to control the movement of the vehicle to search for the target. Therefore, the detection device and the supporting method are relatively simple and easy to implement. Moreover, since the underwater extremely low-frequency electric field signal is used, the loss is small, the line spectrum feature is prominent, and the anti-environmental interference ability is strong, making the present invention highly practical.

[0051] For the underwater spherical object detection method based on an underwater vehicle provided by an embodiment of the present invention, the manufacturing costs of core components such as Ag / AgCl electrodes and metal electrode plates are relatively low, significantly reducing the overall device cost. Compared with an underwater acoustic array that requires a large number of transducers or an optical positioning device that requires expensive optical sensors, the present invention realizes target detection and positioning by measuring and analyzing the changes in the underwater extremely low-frequency electric field signal, and has the characteristics of being economical and efficient, and is particularly suitable for large-scale deployment and application.

[0052] An embodiment of the present invention provides an underwater spherical object detection system based on an underwater vehicle. Refer to Figure 4 , the system includes: an underwater vehicle for carrying a detection device to achieve controllable underwater movement; an electric field emission module for releasing an extremely low-frequency alternating current into the water to apply an electric field signal with a specific distribution in the sea area; an electrode receiving array for measuring the spatial electric field signal in the underwater environment; and a signal processing and control module for loading a corresponding program to implement the underwater spherical object detection method based on an underwater vehicle as described in any one of the foregoing method embodiments.

[0053] Specifically, the underwater vehicle is a movable underwater vehicle, such as an underwater unmanned submersible, an unmanned tracked vehicle, etc., which can be selected according to the characteristics of the detection object and the detection environment. The electric field emission module includes a pair of metal electrodes and an alternating power supply. The metal electrodes are made of materials with corrosion resistance and strong discharge ability, including metal platinum sheets or titanium plates with ruthenium and iridium plating on the outer layer. The electrodes are arranged along the longitudinal or transverse axis of the underwater vehicle, and the alternating power supply applies an extremely low frequency alternating current to the electrode pair. The frequency of the extremely low frequency alternating current applied by the alternating power supply to the metal electrode pair is 10Hz to 30Hz, and the current intensity can be set according to different detection environments and target characteristics. The size and spacing of the metal electrodes can be determined according to different detection requirements. The alternating power supply is placed in the watertight space of the underwater vehicle. The electrode receiving array includes 5 electric field detection electrodes, one of which is used as a reference (hereinafter referred to as a reference electrode), and the other 4 are used for measurement (hereinafter referred to as measurement electrodes). The five electrodes are coplanar, forming an "X" array, and the reference electrode is located at the intersection of the "X" array. The electrical signal amplitude of the measuring electrode relative to the reference electrode is the spatial electric field signal (hereinafter represented by U). The electric field detection electrode is a high-precision Ag / AgCl solid-state electrode. The Ag / AgCl solid-state electrode is symmetrically mounted on the "X" base, and the "X" base is fixed on the underwater vehicle to keep the detection electrode plane parallel to the horizontal plane. The four arms of the "X" base are hollow insulating tubes, and the signal lines of the Ag / AgCl solid-state electrodes are connected to the watertight space of the underwater vehicle through the hollow insulating tubes. The arm length and angle of the "X" base can be adjusted according to actual application requirements. The signal processing and control module completes the processing of the electric field measurement signal, the extraction of the control features and the output of the feedback control signal, thereby realizing the dynamic adjustment of the vehicle motion path. The processing of the electric field measurement signal includes amplifying, filtering, and noise reduction of the four-way spatial electric field signal U obtained in real time during the movement of the vehicle, obtaining the change of the electric field signal relative to the initial state (represented by △U below), thereby extracting the control features, and on this basis, judging whether the target exists, whether the relative distance and direction have changed, and then generating and outputting the feedback control signal according to the control strategy, so as to realize the controllable movement of the vehicle.

[0054] Figure 4 The yellow triangle in the middle marks the metal electrode of the electric field emission module; the red box marks the installation position of the Ag / AgCl reference electrode, and the green circle marks the Ag or AgCl detection electrode. The tracked vehicle (i.e., underwater vehicle) has a roof length of 3m, a bottom length of 4m, a wheelbase of 2m, and a vehicle height of 1.2m. There are two electric field emission electrode sheets, which are installed on the longitudinal axis of the vehicle and are 0.5m above the ground. The extremely low frequency alternating current frequency is 17Hz and the amplitude is 20A.

[0055] The "X" base is fixed on the roof, with an arm length of 2.8m and an angle of 90 0, Four solid-state Ag / AgCl detection electrodes are located at one end of the arm, and the reference electrode is located at the intersection of X. The computer system with the signal processing and control module and the power supply for the whole set of devices are placed in the watertight cavity of the tracked vehicle. After the device provided by the present invention enters the water, the electric field emission module starts to work, applying an extremely low-frequency alternating current to the water area to form a specific spatial distribution of the electric field. The 4 measurement electrodes on the electrode receiving array measure the electric field signals U1, U2, U3, and U4 in the space in real time. The signal processing and control module amplifies and filters the real-time collected electric field signals, and compares the measured electric field signals with the initial state to obtain the change amounts △U1, △U2, △U3, and △U4 of the electric field signals at each electrode. The tracked vehicle drives the measuring device to move. During a period of movement, the electric field distortion also changes continuously, and the corresponding △U1, △U2, △U3, and △U4 at each electrode also change continuously. In this embodiment, after constructing the △U data series based on the test data, the feature points are extracted through the tabu search algorithm, and then with the help of the feedback control algorithm, the traveling direction and speed of the vehicle are dynamically adjusted to efficiently achieve the purpose of target search.

[0056] The implementation basis of each embodiment of the present invention is achieved through programmed processing by a device with a processor function. Therefore, in engineering practice, the technical solutions and functions of each embodiment of the present invention can be encapsulated into various modules. Based on this actual situation, on the basis of the above embodiments, an embodiment of the present invention provides an underwater spherical object detection device based on an underwater vehicle, which is used to execute the underwater spherical object detection method based on an underwater vehicle in the above method embodiment. See Figure 2 , The device includes: a first main module for realizing the underwater maneuver of the underwater vehicle carrying the electric field emission module and the electrode receiving array, and the electric field emission module releases an extremely low-frequency alternating current into the water to form an electric field with a specific distribution in the target area; a second main module for realizing the real-time measurement of the spatial electric field signal by the electrode receiving array and obtaining the electric signal amplitude U of multiple measurement electrodes relative to the reference electrode; a third main module for realizing the processing of the electric signal amplitude U, calculating its change amount △U relative to the initial state, and judging the existence of the target, the relative distance and azimuth of the target according to the extreme value change and distribution characteristics of the change amount △U; a fourth main module for realizing generating a control signal based on the judgment result and adjusting the movement direction and speed of the underwater vehicle to approach the target; a fifth main module for realizing that after approaching the target, after video and image discrimination, if it is not the target, search again, and if it is the target, issue an alarm.

[0057] The underwater spherical object detection device based on an underwater vehicle provided by the embodiment of the present invention adopts Figure 2Some modules in it significantly enhance the detection ability of new concealed underwater spherical objects by adopting active electric field detection means, and can be used as an effective supplement to acoustic, optical, and magnetic detection technologies. It has strong environmental adaptability and can still stably detect in complex environments such as turbid water quality and no light at night. Moreover, the cost of the required electrodes and emission modules is relatively low. By real-time monitoring the change of electric signals, it can accurately locate the target's azimuth and distance, effectively improving the detection efficiency and accuracy.

[0058] It should be noted that the device in the device embodiment provided by the present invention can be used not only to implement the method in the above method embodiment, but also to implement the methods in other method embodiments provided by the present invention. The difference is only in setting the corresponding functional modules. Its principle is basically the same as that of the above device embodiment provided by the present invention. As long as those skilled in the art, on the basis of the above device embodiment, refer to the specific technical solutions in other method embodiments, obtain the corresponding technical means by combining technical features, and the technical solutions composed of these technical means, and ensure the practicability of the technical solutions, they can improve the device in the above device embodiment, so as to obtain the corresponding device type embodiment for implementing the methods in other method type embodiments. For example:

[0059] Based on the content of the above device embodiment, as an optional embodiment, the underwater spherical object detection device based on an underwater vehicle provided in the embodiment of the present invention further includes: a first sub-module for realizing that the frequency of the extremely low frequency alternating current is 10 Hz to 30 Hz, and the current intensity is set according to the detection environment and target characteristics. The electric field emission module includes a pair of metal electrodes arranged along the longitudinal or transverse axis of the underwater vehicle, and the metal electrodes are platinum sheets or titanium plates plated with ruthenium iridium on the outer layer.

[0060] Based on the content of the above device embodiment, as an optional embodiment, the underwater spherical object detection device based on an underwater vehicle provided in the embodiment of the present invention further includes: a second sub-module for realizing that the electrode receiving array is in an "X" shape, including: a reference electrode located at the intersection of the "X", and four measuring electrodes symmetrically distributed at the ends of the four arms of the "X". All the reference electrodes and all the measuring electrodes are silver or silver chloride solid electrodes.

[0061] Based on the content of the above device embodiments, as an alternative embodiment, the underwater spherical object detection device based on an underwater vehicle provided in the embodiments of the present invention further includes: a third sub-module for processing the amplitude U of the electrical signal, including: calculating the change amount ΔU relative to its initial state, setting a threshold ΔUthr, and when the change amount ΔU is greater than the threshold ΔUthr and a maximum value ΔUmax appears, determining the presence of a target; determining that the target is on the side of the electrode with a larger change amount ΔU value by comparing the change amount ΔU values of the four measurement electrodes; and determining the distance change between the target and the underwater vehicle according to the magnitude change of the maximum value ΔUmax of the change amount ΔU.

[0062] Based on the content of the above device embodiments, as an alternative embodiment, the underwater spherical object detection device based on an underwater vehicle provided in the embodiments of the present invention further includes: a fourth sub-module for generating a control signal based on the judgment result and adjusting the movement direction and speed of the underwater vehicle to approach the target, including: the underwater vehicle maneuvers back and forth along a preset "S" - shaped trajectory to cover the search area and confirm the presence of the target by feature; when the change amount ΔU is greater than the threshold ΔUthr and a maximum value ΔUmax appears, controlling the vehicle to turn and continuously adjusting the direction through a closed - loop feedback mechanism until approaching the target.

[0063] Based on the content of the above device embodiments, as an alternative embodiment, the underwater spherical object detection device based on an underwater vehicle provided in the embodiments of the present invention further includes: a fifth sub-module for fixing all reference electrodes and all measurement electrodes to the underwater vehicle through a hollow insulating tube, collecting the electrode signal lines to the watertight space of the vehicle through the hollow insulating tube, and adjusting the arm length and included angle of the "X" - shaped electrode receiving array according to the detection requirements to ensure that the electrode plane is parallel to the horizontal plane.

[0064] To verify the feasibility of the underwater spherical object detection method based on an underwater vehicle provided in the embodiments of the present invention, it is determined through simulation calculations. Among them Figure 5 It is a simulation of the vehicle, target, and environment under Ansys Maxwell software, denoted as Simulation 1. A three - dimensional coordinate system is established, a model calculation domain and a calculation model are constructed, physical and material information parameters are added to it, boundary conditions are clearly set, grid division is designed, and a suitable solver and solver parameters are set according to the calculation requirements. According to the simulation method of the control variable method, by gradually changing some simulation parameters (see Table 1), the influence of each parameter in the active electric field detection is shown.

[0065] Table 1

[0066]

[0067]

[0068] Figure 6 It shows the relationship between the change of △U measured by 4 detection electrodes and the moving position of the vehicle and the x coordinate when the vehicle moves along the E1 trajectory. The potential measured by the No. 1 electrode is U1, the amplitude of the electrical signal measured by the No. 2 electrode is U2, the amplitude of the electrical signal measured by the No. 3 electrode is U3, and the amplitude of the electrical signal measured by the No. 4 electrode is U4. It can be seen from the figure that for the detection electrodes (No. 1 and No. 2 electrodes) close to the target, the change of △U is large, and the change amplitude is about 24 mV to 27 mV; for the detection electrodes (No. 3 and No. 4 electrodes) far from the target, the change of △U is small, and the change amplitude is about 7 mV to 10 mV. This is the first characteristic; when the vehicle approaches the target, △U increases, and when it moves away from the target, △U decreases. When it is closest to the target, △U will be the maximum value. This is the second characteristic; for the part where △U is greater than the threshold, the vehicle travels about 10 m and a maximum value appears. This is the third characteristic.

[0069] Figure 7 It is △U detected by the No. 1 and No. 2 electrodes when the vehicle moves along the three trajectories of E1, E2, and E3. It can be obtained from the figure that on the same plane, as the lateral distance between the detection device and the target increases, the change amplitude of the disturbance quantity △U decreases, and vice versa, the disturbance quantity △U increases. This is the fourth characteristic; under the condition that the lateral distance remains unchanged, as the vertical position of the sensor changes, the disturbance quantity △U has a slight change but the effect is not significant, indicating that under the above conditions, the layout depth of the sensor has little influence on the detection performance. Appropriately relax the height limit of the electrode receiving array to improve the obstacle-crossing ability of the device.

[0070] The performance indicators of the detection method of this device consist of three parts: the maximum detection distance, the maximum detection range, and the earliest warning distance. As Figure 8 shown, two thresholds of 5 mV and 3 mV are set for △U. When △U is equal to the threshold, the vertical projection distance between the vehicle and the target on the path is recorded as the earliest warning distance, the interval where △U is greater than the threshold is recorded as the maximum detection range, and the lateral distance of the target when the maximum value of △U is equal to the threshold is recorded as the maximum detection distance. From Figure 9 、 Figure 10 it can be seen that when the characteristic parameters of the device and the target remain unchanged, the closer the lateral distance of the target distance search path is, the greater the earliest warning distance and the maximum detection range are. When the 5 mV threshold is set, the performance indicators of the device are lower than those when the 3 mV threshold is set, and the gap increases as the lateral distance of the target decreases.

[0071] According to Figure 11 、 Figure 12It can be seen that the maximum detection distance of the device is related to the target radius and the current of the electric field emission module. When the current of the electric field emission module remains unchanged at 20 A, as the target radius increases, the detectable range increases non-linearly. When the target radius is 0.4 m, the detection distance of the device is about 4 m; when the target radius is 0.6 m, the detection distance of the device at a 5 mV threshold is 22 m, and the detection distance at a 3 mV threshold is 26 m. According to the analysis of the target perturbation characteristics, this phenomenon occurs because under the same electric field and position parameter conditions, the peak value of the perturbation will show a cubic power non-linear change with the change of the target size. According to this characteristic, by adjusting the magnitude of the current and analyzing the change law of its △U, the size is discriminated, which is characteristic five. When the target radius remains unchanged at a radius of 0.5 m, the maximum detection distance increases exponentially with the increase of the current. When the current of the electric field emission module is 20 A, the detection distance of the device is about 9 m; when the current of the electric field emission module is less than 40 A, the detection distance of the device is less than 27 m. Therefore, the detection and search efficiency of the vehicle is improved by increasing the current.

[0072] To sum up, it can be determined whether the change of △U is caused by the target according to characteristic three of the device, the azimuth relationship between the target and the vehicle can be discriminated according to characteristics one and two of the change of △U, the distance between the target and the vehicle can be judged according to characteristic four, and the target size can be discriminated according to characteristic five of the change law of △U under different currents.

[0073] (1) Structure of the experimental model of the detection device:

[0074] Since the laboratory conducts experimental tests to verify the detection method and the correctness of the design of the detection device based on finite element simulation, the experiment does not have to be based on a mobile vehicle platform. The mobile vehicle platform can be replaced by connecting a mobile guide rail and using a telescopic insulating bracket in the middle. The specific structure and parameters are as Figure 13 、 Figure 14 shown.

[0075] Figure 13 Shows the specific structure of the experimental model of the detection device, where:

[0076] 1) The mobile guide rail adapts to the pod 1 for mounting the detection device;

[0077] 2) The first extended support rod 2 and the second extended support rod 3 are designed with threads for dynamically adjusting the depth;

[0078] 3) The sensor array fixing bracket 4;

[0079] 4) The first electrode fixing head 51, the second electrode fixing head 52, the third electrode fixing head 53, and the fourth electrode fixing head 54 are four electrode fixing heads;

[0080] 5) The first field source platinum sheet fixing head 61 and the second field source platinum sheet fixing head 62 are two field source platinum sheet fixing heads;

[0081] 6) The field source and reference electrode fixing bracket 7 fixes the reference electrode in the middle of the positive and negative electrodes;

[0082] 7) After the physical assembly of the detection device is completed, according to the laboratory size, target size and analysis of the performance of the detection device, adjust the specific device parameters as Figure 14 shown.

[0083] Assembly of the experimental model of the detection device

[0084] 1) Figure 14 In the figure, the fixing heads and their support structures equipped with each installation electrode and field source platinum sheet adopt a hollow design method, and the wires are smoothly passed out from the inside. While not affecting the movement of the detection device and the electric field distribution, a stable connection with the signal acquisition system and the excitation emission device is achieved;

[0085] 2) The field source platinum sheet is stably fixed to the wire through a precision welding process. Subsequently, a high-performance silicon-based waterproof sealant is used to comprehensively seal the welding interface between the wire and the back of the platinum sheet, as well as the connection point between the wire and the fixing rod, so as to effectively isolate the saline water environment and avoid weakening the field source discharge efficiency due to the wire participating in the electrolysis reaction under the energized state, and even affecting the distribution of the entire electric field;

[0086] 3) After determining the appropriate distance between the field source and the electrode, the length and installation angle of each threaded connection part need to be adjusted to ensure that the layout of the field source and the sensor approaches the ideal symmetric state to the greatest extent. After preliminary calibration, fine-tuning still needs to be carried out according to the feedback of the measured data to optimize the system configuration and ensure that the overall performance reaches the best state.

[0087] (3) Position calibration and establishment of coordinate system:

[0088] 1) Debug the movement trajectory of the device to ensure that it moves on the central axis of symmetry in the pool, ensure the symmetry of the experimental measurement, and firmly fix both ends of the debugged guide rail, and mark this state as the standard center line position of the system, as Figure 15 shown.

[0089] 2) Subsequently, take the geometric center of the bottom plane of the water tank as the coordinate origin to construct a rectangular coordinate system, where the z-axis is perpendicular to the origin and points vertically upward, and the x-axis is horizontal and points to the right.

[0090] 3) Determine the coordinate relationship of the platinum sheet electrode and each detection electrode.

[0091] (4) Experimental design

[0092] On the basis of the above work, an alternating current with an amplitude of 0.375 A and a frequency of 17 Hz is applied to the platinum sheet electrode, and the detection of targets at different positions is completed on different movement trajectories to comparatively analyze the detection performance of the established experiment. Each group of experiments is measured back and forth twice, and the average value of the alternating signal envelope is processed symmetrically to improve the data accuracy. For the illustration of the experimental layout of each group of experiments, see Figure 15 .

[0093] In the experiment, the targets are respectively set at three positions: T1(0, -0.15, 0.155) m, T2(0, -0.20, 0.155) m, and T3(0, -0.25, 0.155) m. The movement trajectory of the experimental model is identified by the movement trajectory of the intersection point of the diagonals of the four detection electrodes, which are respectively set as M1, M2, and M3. Among them, M1: x ∈ (-0.8, 0.8) m, y = 0 m, z = 0.215 m, M2: x ∈ (-0.8, 0.8) m, y = 0 m, z = 0.2295 m, M3: x ∈ (-0.8, 0.8) m, y = 0 m, z = 0.244 m.

[0094] (5) Experimental results and simulation analysis

[0095] Figure 16 , 17 shows the measurement results of the spherical targets at different positions when the experimental model moves along each trajectory. In the figure, (M1, T1) means moving along M1 and detecting the T1 target, and the rest are understood similarly. The measurement results of the disturbance quantity ΔU of the alternating field by the four detection electrodes in the model are also given in the figure. For convenient comparative analysis, the finite element simulation results under the experimental parameter conditions are synchronously given, and this simulation model is denoted as Simulation Two.

[0096] From Figure 16 , 17 it can be seen that: by changing the target position and the device trajectory path, the experimental results and the simulation results can be in good agreement. Analyzing from the distribution characteristics of ΔU measured by its 4 detection electrodes, the influence of the target position distance on the detection search in the experiment is the same as the simulation conclusion of Simulation One, indicating the effectiveness of the finite element simulation model in simulating and analyzing the target detection problem in such detection scenarios and the feasibility of this detection device to achieve target detection directionally.

[0097] The method of the embodiment of the present invention is implemented relying on an electronic device, so it is necessary to introduce the relevant electronic device. For this purpose, an embodiment of the present invention provides an electronic device, such as Figure 3As shown, the electronic device includes: at least one processor, a communications interface, at least one memory, and a communication bus. Among them, the at least one processor, the communications interface, and the at least one memory communicate with each other via the communication bus. The at least one processor can invoke the logic instructions in the at least one memory to execute all or part of the steps of the methods provided in the foregoing various method embodiments.

[0098] In addition, when the logic instructions in the above-mentioned at least one memory can be implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various method embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

[0099] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without creative effort.

[0100] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the technical solution, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disc, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0101] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. With this understanding, each block in the flowchart or block diagram may represent a module, a segment of a program, or a portion of code that contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions noted in the blocks may occur in a different order than noted in the accompanying drawings. For example, two consecutive blocks may in fact be executed substantially in parallel, or sometimes in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or by a combination of dedicated hardware and computer instructions.

[0102] It should be noted that the term "comprising", "including", or any other variation thereof is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, the elements defined by the statement "comprising..." do not preclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the said elements. For any "predetermined threshold", "preset threshold" or similar expressions, if no specific numerical value is indicated, those of ordinary skill in the art can determine their specific numerical values through simple experiments or corresponding debugging.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An underwater spherical object detection method based on an underwater vehicle, characterized in that, include: The underwater vehicle is equipped with an electric field transmitting module and an electrode receiving array and maneuvers underwater. The electric field transmitting module releases an extremely low frequency alternating current into the water to form an electric field with a specific distribution in the target area. The electrode receiving array measures the spatial electric field signal in real time, and obtains the electric signal amplitude U of the multi-channel measuring electrodes relative to the reference electrode; the electric signal amplitude U is processed, and its change △U relative to the initial state is calculated, and according to the extreme value change and distribution characteristics of the change △U, it is judged whether the target exists, the relative distance and direction of the target; based on the judgment result, a control signal is generated to adjust the movement direction and speed of the underwater vehicle to approach the target; after approaching the target, after video and image identification, if it is not the target, it will search again, and if it is the target, an alarm will be issued.

2. The underwater spherical object detection method based on an underwater vehicle according to claim 1, characterized in that The frequency of the extremely low frequency alternating current is 10 Hz to 30 Hz, and the current intensity is set according to the detection environment and target characteristics. The electric field emission module includes a pair of metal electrodes arranged along the longitudinal or transverse axis of the underwater vehicle, and the metal electrodes are metal platinum sheets or titanium plates with ruthenium and iridium plated on the outer layer.

3. The underwater spherical object detection method based on an underwater vehicle according to claim 2, wherein, The electrode receiving array is in the shape of "X", including: a reference electrode located at the intersection of "X", four measuring electrodes symmetrically distributed at the ends of the four arms of "X", and all reference electrodes and all measuring electrodes are silver or silver chloride solid electrodes.

4. The underwater spherical object detection method based on an underwater vehicle according to claim 3, wherein The processing of the electrical signal amplitude U includes: calculating the change △U relative to the initial state, setting a threshold △Uthr, and determining that the target exists when the change △U is greater than the threshold △Uthr and a maximum value △Umax appears; determining that the target is located on the side of the electrode with a larger change △U value by comparing the change △U values ​​of the four measuring electrodes; and determining the change in the distance between the target and the underwater vehicle according to the change in the size of the maximum value △Umax of the change △U.

5. The method for detecting an underwater spherical object based on an underwater vehicle according to claim 4, wherein The control signal is generated based on the judgment result to adjust the movement direction and speed of the underwater vehicle to approach the target, including: the underwater vehicle maneuvers back and forth along a preset "S"-shaped trajectory to cover the search area, and confirms the existence of the target according to the characteristics of the change amount △U in a single or multiple cruises; when the change amount △U is greater than a threshold value △Uthr and a maximum value △Umax appears, the vehicle is controlled to turn, and the direction is continuously adjusted through a closed-loop feedback mechanism until it approaches the target.

6. The underwater spherical object detection method based on an underwater vehicle according to claim 5, characterized in that, All reference electrodes and all measuring electrodes are fixed on the underwater vehicle through hollow insulating tubes. The electrode signal lines are connected to the watertight space of the vehicle through hollow insulating tubes. The arm length and angle of the "X"-shaped electrode receiving array are adjusted according to detection requirements to ensure that the electrode plane is parallel to the horizontal plane.

7. An underwater spherical object detection system based on an underwater vehicle, characterized in that, include: An underwater vehicle for carrying a detection device to achieve controllable underwater movement; an electric field transmitting module for releasing an extremely low frequency alternating current into the water to apply a specific distributed electric field signal in the sea area; an electrode receiving array for measuring the spatial electric field signal in the underwater environment; a signal processing and control module for loading a corresponding program to implement the underwater spherical object detection method based on an underwater vehicle as described in any one of claims 1 to 6.

8. An underwater spherical object detection device based on an underwater vehicle, characterized in that, include: The first main module is used to realize the underwater maneuver of the underwater vehicle carrying the electric field emission module and the electrode receiving array. The electric field emission module releases extremely low-frequency alternating current into the water to form an electric field with a specific distribution in the target area. The second main module is used to realize the real-time measurement of the spatial electric field signal by the electrode receiving array and obtain the electric signal amplitude U of multiple measurement electrodes relative to the reference electrode. The third main module is used to process the electric signal amplitude U, calculate the change amount △U relative to its initial state, and judge the existence of the target, the relative distance and azimuth of the target according to the extreme value change and distribution characteristics of the change amount △U. The fourth main module is used to generate a control signal based on the judgment result and adjust the movement direction and speed of the underwater vehicle to approach the target. The fifth main module is used to realize that after approaching the target, after video and image discrimination, if it is not the target, search again, and if it is the target, issue an alarm.

9. An electronic device, characterized in that, Comprising: At least one processor, at least one memory and a communication interface; wherein, The processor, the memory and the communication interface communicate with each other; The memory stores program instructions executable by the processor, and the processor calls the program instructions to execute the method according to any one of claims 1 to 6.

10. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions, and the computer instructions cause the computer to execute the method according to any one of claims 1 to 6.

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