Cooperative mapping method and device for underwater objects, water surface control device and medium

Abstract

The application relates to the technical field of surveying and mapping, and discloses a cooperative surveying and mapping method and device for underwater objects, a water surface control device and a medium. The method comprises the following steps: controlling a ROV to dive to a target depth, constructing a flow field profile based on layered flow data collected by the master-slave ROVs at different depths; selecting a point at a guard distance from the measured object downstream region as the slave ROV anchor point according to the flow direction at the depth of the slave ROV and performing point hovering; determining a three-dimensional safe operation space of the master ROV according to cooperative operation constraint parameters such as cable length, guard distance, working distance and real-time flow conditions; and controlling the master ROV to perform partition detection on the measured object at a working distance within the safe space. The application actively avoids the umbilical cable winding risk through double-ROV layered flow perception and automatic anchor point laying in the downstream, realizes task separation of fine detection and cable global monitoring, and the safe operation space can dynamically adapt to complex hydrological conditions.

Description

Technical Field

[0001] This application relates to the field of surveying and mapping technology, and in particular to a collaborative surveying and mapping method, apparatus, surface control equipment and storage medium for underwater objects. Background Technology

[0002] Structural condition inspection of underwater objects such as underwater pile foundations and subsea pipelines is a crucial step in ensuring the safe operation of marine engineering facilities. Currently, this type of inspection is typically performed using underwater robots equipped with acoustic and optical detection payloads.

[0003] However, water in actual operating environments often exhibits stratified flow characteristics, with significant differences in flow direction and velocity at different depths. This results in complex spatial morphological changes in the cables connecting the robot and the surface unit. Simultaneously, the object being measured itself disturbs the surrounding flow field, creating areas of flow around and turbulence, further increasing the uncertainty of the cable's attitude and raising the risk of the cable becoming entangled or damaged by the object.

[0004] Current methods of using a single robot for detection still face several operational bottlenecks. During detection, operators find it difficult to simultaneously maintain close-up, detailed observation of the object's surface and a comprehensive understanding of the overall position and orientation of the cable. If the planning of the detection coverage area lacks sufficient basis, some areas may be repeatedly detected while others are missed, affecting the completeness of data acquisition and operational efficiency.

[0005] The aforementioned problems are even more prominent under complex hydrological conditions such as dynamic changes in the flow field and limited underwater visibility, which places higher demands on the environmental adaptability and autonomy of underwater object detection schemes. Summary of the Invention

[0006] Based on this, it is necessary to address the technical problems of low surveying efficiency and poor applicability in complex environments when performing surveying operations in existing technologies. Therefore, a collaborative surveying method, device, surface control equipment, and storage medium for underwater objects are proposed.

[0007] In a first aspect, a collaborative mapping method for underwater objects is provided, applied to a surface control device, wherein the surface control device is communicatively connected to a master ROV and a slave ROV, and the master ROV and the slave ROV are connected to the same umbilical cable; the method includes: The ROV is controlled to descend to a preset target depth, and a flow field profile is constructed based on the stratified water flow data collected at different depths by the main ROV and the secondary ROV. Based on the water flow direction at the depth of the ROV in the flow field profile, a point at a monitoring distance from the object being measured is selected as the anchor point of the ROV in the downstream region relative to the object being measured, and the ROV is controlled to hover at the anchor point. Based on the collaborative operation constraint parameters and the real-time water flow conditions, the current three-dimensional safe operating space of the main ROV is determined; wherein, the collaborative operation constraint parameters include at least: the cable length between the main ROV and the slave ROV, the monitoring distance, and the working distance between the main ROV and the object under test; the cable length, monitoring distance, and working distance are preset; the monitoring distance is greater than the working distance; The main ROV is controlled to perform zoned detection of the object under test within the three-dimensional safe working space at the working distance.

[0008] Secondly, a cooperative detection device for underwater objects is provided, the device comprising: The module is used to control the ROV to descend to a preset target depth and to construct a flow field profile based on the stratified water flow data collected at different depths from the main ROV and the secondary ROV. The selection module is used to select a point at a monitoring distance from the object being measured as the anchor point of the ROV in the downstream region relative to the object being measured, based on the water flow direction at the depth of the ROV in the flow field profile, and to control the ROV to hover at the anchor point. The determination module is used to determine the current three-dimensional safe operating space of the main ROV based on collaborative operation constraint parameters and real-time water flow conditions; wherein, the collaborative operation constraint parameters include at least: the cable length between the main ROV and the slave ROV, the monitoring distance, and the working distance between the main ROV and the object under test; the cable length, monitoring distance, and working distance are preset; the monitoring distance is greater than the working distance; The control module is used to control the main ROV to perform zonal detection of the object under test within the three-dimensional safe working space at the working distance.

[0009] Thirdly, a water surface control device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described intelligent question-and-answer processing method.

[0010] Fourthly, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described intelligent question-answering processing method.

[0011] The beneficial effects of this application are: First, this application utilizes dual ROVs to collaboratively collect water flow data at different depths and construct flow field profiles. This enables the surface control device to acquire complete water flow distribution information from the surface to the bottom around the measured object, rather than relying on point-like water flow sensing at a single depth. Based on this, the surface control device selects points downstream of the measured object, at a monitoring distance from the object, as anchor points for the secondary ROV, according to the water flow direction at the depth of the ROV. This anchor point deployment strategy ensures that the umbilical cable connecting the primary and secondary ROVs naturally drifts away from the measured object under the influence of water flow, avoiding the risk of the umbilical cable being attracted to or entangled by turbulent currents from the source. This solves the problems of difficulty in actively controlling cable attitude and susceptibility to the combined effects of stratified water flow and pile disturbance in existing single-robot operations.

[0012] Secondly, this application adopts a master-slave dual ROV architecture and sets the monitoring distance to be greater than the working distance. This allows the slave ROV to form a fixed anchor point in a safe area outside the object being measured, dedicated to the task of global cable situational awareness and environmental perception, while the master ROV performs fine detection at a closer working distance to the object surface. This spatial division of labor resolves the contradiction in existing single-robot solutions where operators cannot simultaneously perform close-range fine observation and global cable monitoring, ensuring both the quality of the detection data acquisition and effective control over the spatial attitude of the cable.

[0013] Third, this application calculates the three-dimensional safe operating space of the main ROV by jointly solving the collaborative operation constraint parameters and real-time water flow conditions, and integrates multiple physical constraints such as cable length, monitoring distance, and working distance with dynamic water flow conditions into the spatial delineation logic. Unlike existing methods that rely on operator experience or preset paths, the safe operating space of this solution is quantitatively calculated based on real-time environmental data and preset constraint parameters. It has repeatability and adaptability, and can autonomously generate suitable safe operating boundaries under different water depths and flow conditions, providing a reliable spatial benchmark for subsequent zonal detection of the main ROV within the safe boundary.

[0014] In summary, this application, through dual ROV layered water flow sensing, automatic deployment of downstream anchor points, and three-dimensional safe operating space calculation based on multi-source constraints, achieves proactive avoidance of umbilical cable entanglement risk, separation of tasks for fine detection and global monitoring, and dynamic adaptive delineation of safe operating space under complex hydrological conditions, thereby improving the overall safety and environmental adaptability of underwater object detection operations. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] in: Figure 1 This is a schematic diagram of a scenario for the underwater observation system improved in the embodiments of this application; Figure 2 A flowchart illustrating the collaborative mapping method for underwater objects provided in this application embodiment; Figure 3 This is a schematic diagram of the loop detection process provided in the embodiments of this application; Figure 4 This is a schematic diagram of the process for constructing a flow field profile provided in an embodiment of this application; Figure 5 This is a flowchart illustrating the process of determining the anchor point position provided in an embodiment of this application; Figure 6 This is a schematic diagram of the anchor point candidate region provided in the embodiments of this application; Figure 7 This is a schematic diagram of the process for constructing a three-dimensional safe working space provided in an embodiment of this application; Figure 8 This is a schematic diagram of the first safe distance provided in the embodiments of this application; Figure 9 This is a schematic diagram of the second safety distance provided in the embodiments of this application; Figure 10 This is a structural block diagram of the cooperative underwater object detection device provided in the embodiments of this application; Figure 11 This is a structural block diagram of the water surface control device provided in the embodiments of this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] See Figure 1As shown, the underwater observation system of this application includes: a surface control device, a surface base station, and at least two underwater robots. The surface control device can communicate with the underwater robots via cables or the surface base station. In some embodiments, the surface control device can also be mounted on the surface base station.

[0019] At least two underwater robots, including a master ROV (Remotely Operated Vehicle) and a slave ROV, are connected by a cable (e.g.: Figure 1 (The umbilical cable shown) and communication. The underwater robots mentioned above include, but are not limited to, tethered remotely operated underwater robots and autonomous / remotely controlled underwater vehicles (ARVs), and may also be underwater detection equipment, underwater submarine equipment or other underwater operation equipment. This application does not limit this.

[0020] The surface control equipment is installed in the aquatic environment to provide underwater robots with navigation paths for observing underwater objects (such as bridge piers, ship hulls, etc.), and to configure the navigation paths to the designated underwater robots. The underwater robots then observe the objects based on the navigation paths to monitor for defects such as cracks and corrosion. The surface control equipment can be a mobile device, tablet computer, or fixed computer, etc., and this application does not impose any restrictions on this.

[0021] Floating base stations can also take the form of ship hulls or other waterborne equipment. They are typically equipped with GNSS (Global Navigation Satellite System) and a USBL (Ultra-Short Baseline) transducer array positioned below the water surface. Floating base stations also serve as communication hubs between surface control equipment and underwater robots, handling task scheduling and ensuring coordinated responses from surface control equipment and underwater robots. In some embodiments, the floating base station also has the capability to supply power to the underwater robot.

[0022] In this embodiment, the underwater robot is equipped with a USBL transponder, which works in conjunction with a USBL transducer array set up at a surface base station for collaborative positioning. The positioning principle is as follows: the surface base station obtains the surface position coordinates based on its GNSS module; the underwater robot uses the USBL transponder to measure the relative position offset between itself and the surface base station; and then calculates its own current position coordinates based on the relative position offset and the position coordinates of the surface base station. In addition, the underwater robot is also equipped with a multi-beam Doppler velocimeter (DVL), which can accurately detect the relative distance to the underwater object in real time, simultaneously performing underwater attitude positioning, speed calculation, and spatial ranging operations. This provides reliable environmental ranging and motion attitude data support for the robot's autonomous underwater navigation, close-range observation, and precise operations.

[0023] The present application will now be described in detail through specific embodiments.

[0024] Please see Figure 2 As shown, Figure 2 A flowchart illustrating the collaborative mapping method for underwater objects provided in this application embodiment includes the following steps: S1. Control the ROV to descend to the preset target depth, and construct the flow field profile based on the stratified water flow data collected at different depths by the main ROV and the slave ROV.

[0025] The surface control equipment controls the ROV's descent to a preset target depth, which is a pre-determined water depth based on the mission requirements. During descent and upon reaching the target depth, the surface control equipment receives flow data collected by both the main and secondary ROVs at different depths. This flow data includes at least information on the flow direction and velocity. Since the main and secondary ROVs are located at different depths vertically, their flow data complement each other in depth coverage. The surface control equipment fuses this flow data from different depth ranges to construct a three-dimensional flow model describing the distribution of flow direction and velocity from the surface to the bottom. This three-dimensional flow model is the flow field profile. The flow field profile represents the spatial distribution of water flow within the current probed area and serves as the environmental basis for subsequent anchor point selection and spatial decisions.

[0026] S2. Based on the direction of water flow at the depth of the ROV in the flow field profile, select a point at a monitoring distance from the object being measured as the anchor point of the ROV in the downstream region relative to the object being measured, and control the ROV to hover at the anchor point.

[0027] The process involves the surface control equipment first extracting the current direction corresponding to the target depth of the ROV from the flow field profile constructed in step S1. Then, using the known spatial location of the object being measured as a reference, the surface control equipment selects a point downstream of this current direction as the anchor point for the ROV. The object being measured refers to the underwater target to be detected in this mission, such as underwater piles or underwater structures. The monitoring distance is the pre-set spatial distance between the anchor point of the ROV and the surface of the object being measured. This distance must ensure that the ROV is within the safe perimeter of the object, neither too far to lose effective monitoring of the cable's position nor too close to cause itself or the cable to become trapped in a turbulence risk zone. After point selection, the surface control equipment sends a hovering command to the ROV, controlling it to maintain its position at that anchor point, thus forming a stable spatial reference.

[0028] S3. Determine the current three-dimensional safe operating space of the main ROV based on the collaborative operation constraint parameters and the real-time water flow conditions.

[0029] Among them, the collaborative operation constraint parameters include at least: the cable length between the master ROV and the slave ROV, the monitoring distance, and the working distance between the master ROV and the object being measured; the cable length, monitoring distance, and working distance are preset; the monitoring distance is greater than the working distance.

[0030] The surface control equipment determines the real-time three-dimensional safe operating space of the main ROV based on collaborative operation constraint parameters and real-time water flow conditions. These water flow conditions include at least flow direction, velocity, and stratified velocity profiles. Collaborative operation constraint parameters are pre-configured physical and geometric parameters that define the activity boundary of the main ROV. These parameters include at least the cable length between the main and slave ROVs, the monitoring distance, and the working distance between the main ROV and the object being measured. The working distance refers to the distance the main ROV should maintain from the surface of the object being measured during detection; this distance is freely set by the imaging requirements of the detection sensors or actual operational needs. The cable length refers to the length of the umbilical cable between the main and slave ROVs. Furthermore, the monitoring distance is greater than the working distance, ensuring that the slave ROV is positioned further away from the object being measured compared to the main ROV. The surface control equipment combines the aforementioned constraint parameters with the real-time water flow conditions at the location of the main ROV. Through spatial geometric calculations, it derives a spatial region where every point satisfies all constraints. Within this region, the main ROV will not face risks such as cable entanglement with the anchor pile or collision with the slave ROV. This spatial region is the three-dimensional safe operating space. For example, the three-dimensional safe operating space is a lower hemisphere with the anchor point of the slave ROV as its center and the cable length L1 as its radius.

[0031] S4. Control the main ROV to perform zoned detection of the object under test at working distance within the three-dimensional safe working space.

[0032] Within the three-dimensional safe operating space, a zoned detection is performed at a working distance close to the surface of the object being measured. Zoned detection refers to the detection and coverage of a localized area on the surface of the object being measured. The surface control equipment plans the main ROV's detection path based on the boundary shape of the three-dimensional safe operating space, ensuring that the main ROV maintains a distance equal to the working distance from the surface of the object being measured while completing data acquisition for the current area. During the detection process, the detection equipment onboard the main ROV, such as a high-definition optical camera or imaging sonar, continuously collects image or acoustic data from the surface of the object being measured. This data is transmitted in real-time from the main ROV to the surface control equipment via a communication link integrated in the umbilical cable. The surface control equipment receives and records the mapping data transmitted back by the main ROV, associating and storing it with the spatial location information of the current zone.

[0033] In one example, with a working distance set to 2 meters, the main ROV scans an area on the north side of the pile being measured within a three-dimensional safe working space. The high-definition camera on the main ROV captures images of the weld seams on the pile surface at a rate of 30 frames per second. Each frame, along with the ROV's attitude data and spatial coordinates at the time of capture, is uploaded in real-time via a fiber optic channel within the umbilical cable. The surface control equipment decodes and stores the image stream at the receiving end and displays it on a monitor in real-time, allowing operators to check for cracks or corrosion defects in the weld seams. When the survey of this section is completed, the surface control equipment has fully acquired all the mapping data for that area and marked it as a surveyed area, providing a basis for subsequent anchor point updates and the next section survey.

[0034] In an optional implementation, see Figure 3 As shown, Figure 3 The flowchart of the cyclic detection provided in the embodiments of this application specifically includes the following steps: S5. In response to the completion of the current zone detection, the ROV will be updated from its anchor point along the circumference of the object being measured to the next position, and the three-dimensional safe working space of the main ROV will be redefined to perform the next zone detection. This process will continue until the full circumferential detection of the object being measured at its current depth is completed.

[0035] After the main ROV completes its zone detection task within the current three-dimensional safe operating space, the surface control equipment immediately initiates the anchor point update process to prepare for the next zone detection. The surface control equipment records the circumferential angle range covered by the area currently detected by the main ROV and, combined with real-time water flow data obtained from the flow field profile, calculates the direction and magnitude of the ROV's anchor point movement. The movement is along the circumference of the object being measured, i.e., rotating clockwise or counterclockwise around the outer contour of the object. Each rotation is a preset fixed angular interval. When calculating the spatial coordinates of the new anchor point, the surface control equipment keeps the anchor point's depth and monitoring distance from the surface of the object unchanged, only changing its azimuth angle relative to the object. After the new anchor point is determined, the surface control equipment uses this new anchor point as a reference to re-execute the three-dimensional safe operating space calculation, i.e., determining the main ROV's safe activity boundary in the next zone based on the collaborative operation constraint parameters and the real-time water flow conditions at the new anchor point. Then, the surface control equipment sends a movement command to the ROV, instructing it to move from its current position to the new anchor point and hover there again. Simultaneously, it sends a command to the main ROV, instructing it to perform the next zone of detection within the newly defined three-dimensional safe operating space. This process is repeated, each cycle covering one angular sector of the circumference of the object being measured, until all sectors are combined to cover the complete 360-degree circumferential range, thus completing the full circumferential detection of the object at that depth.

[0036] In one example, a preset angle interval of 90 degrees can be set, with the initial detection orientation being the north side of the pile being measured. After the main ROV completes the zonal detection within the 0-90 degree sector on the north side, the surface control equipment, based on the current flow field profile data, decides to update the anchor point in a clockwise direction. Maintaining the anchor point depth at 30 meters and the monitoring distance at 10 meters, the surface control equipment adjusts the azimuth of the measured object from north to east, calculating the coordinates of a new anchor point located on the east side of the pile. Then, using the new anchor point as the center, the three-dimensional safe operating space is recalculated, and commands are issued to both the secondary and main ROVs, causing the secondary ROV to move to the new anchor point on the east side and hover, while the main ROV performs detection within the safe space on the east side, covering the 90-180 degree sector. Subsequently, this process continues sequentially, updating to the south anchor point to complete the 180-270 degree sector detection, and updating to the west anchor point to complete the 270-360 degree sector detection. To ensure no measurement is missed between adjacent zones, each defined three-dimensional safe working space overlaps with the previous zone on its circumferential boundary, for example, with an overlap angle of 5 degrees. After multiple iterations of this process, the entire circumferential detection of the pile can be completed.

[0037] S6. After completing the full circumferential detection at the current depth of the object being measured, adjust the target depth from the ROV and re-execute the steps of anchor point selection, three-dimensional safe working space determination, and cyclic detection to achieve detection of different depth sections of the object being measured.

[0038] After completing the full circumferential detection at the current depth of the object being measured, the surface control equipment initiates a depth-oriented detection extension process. Based on a preset depth step, the surface control equipment calculates a new target depth. This new target depth can be shallower or deeper than the current depth, depending on whether the overall detection task is performed from top to bottom, bottom to top, or in segments. Once the new target depth is determined, the surface control equipment sends a dive or surface command to the ROV to reach the new target depth. Upon arrival, the surface control equipment reconstructs a new flow field profile based on the stratified flow data collected by the main ROV and the ROV at the new depth. Then, based on the flow direction at the depth of the ROV in the new flow field profile, a new anchor point is selected at that depth, and the ROV is controlled to hover at that point. Next, based on the collaborative operation constraint parameters and the flow conditions at the new anchor point, the three-dimensional safe operating space of the main ROV at the new depth is redefined. Finally, the circumferential cyclic detection process described in step S5 is repeated to complete the full circumferential detection at the new depth. By advancing layer by layer, comprehensive detection coverage of different depth sections of the object being measured can be achieved.

[0039] In one example, after completing circumferential probing of the anchor point at a depth of 30 meters, the surface control equipment sets the new anchor point depth to 35 meters based on a preset 5-meter depth step. The surface control equipment sends a dive command to the slave ROV, causing it to descend from 30 meters to 35 meters. During the slave ROV's descent, the main ROV can also synchronously adjust to a depth near 35 meters. Upon arrival, both the main and slave ROVs re-collect stratified flow data around the 35-meter depth, and the surface control equipment merges this data to generate a new flow field profile. Assuming the flow direction at 35 meters changes to southeast, the surface control equipment selects a new anchor point on the southeast side of the pile, controls the slave ROV to hover, and calculates the three-dimensional safe operating space for the main ROV at the 35-meter depth. Then, the main ROV cyclically completes the zonal probing around the pile in 90-degree circumferential steps. This process continues until the entire depth of the pile is covered.

[0040] This embodiment combines circumferential cyclic detection with layer-by-layer depth expansion, enabling a master-slave dual ROV collaborative system driven by the surface control equipment to achieve fully automatic three-dimensional detection of the object under test. Throughout the detection process, the dynamic selection of anchor points, real-time calculation of safe operating space, and automatic connection of detection areas are all automatically completed by the surface control equipment based on real-time water flow data and preset constraint parameters. No manual pre-planning of the detection path or manual intervention in anchor point switching is required. Under hydrological conditions involving complex stratified water flow and pile disturbance, this method systematically avoids the risk of umbilical cable entanglement and ensures controllable overlap between adjacent detection areas. Thus, while ensuring equipment safety, it achieves high-precision mapping of underwater objects in all directions and depths without blind spots.

[0041] In one optional implementation, after the main ROV completes its current zone detection task, the surface control equipment begins updating the anchor points along the circumference of the object being measured, preparing for the detection of the next zone. The core requirement of anchor point updating is to rotate the secondary ROV around the object being measured by a preset angle while maintaining the detection depth, thereby allowing the main ROV to obtain a new three-dimensional safe operating space in the new orientation, and thus cover the next circumferential area of ​​the object being measured.

[0042] The surface control equipment follows three invariable principles when updating anchor points. First, the depth remains constant; the depth of the new anchor point is exactly the same as the current anchor point. Second, the monitoring distance remains constant; the distance from the new anchor point to the surface of the object being measured remains at the preset monitoring distance. Third, the rotation direction remains constant; throughout the entire circumferential detection cycle, the anchor point always rotates in the same direction, either clockwise or counterclockwise. The surface control equipment calculates the azimuth angle of the new anchor point based on preset angular intervals, and, combined with the position information of the object being measured and the monitoring distance, calculates the spatial coordinates of the new anchor point.

[0043] While calculating the coordinates of the new anchor point, the surface control equipment also needs to ensure that the three-dimensional safe operating spaces of the main ROV corresponding to two adjacent detection cycles have a preset angle of overlap. This overlap is set to eliminate detection blind spots between adjacent zones. Due to factors such as potential fluctuations in water flow conditions, slight deviations between the actual movement path of the main ROV and the planned path, and changes in the surface curvature of the measured object, if the safe operating spaces of adjacent zones are exactly adjacent at the boundary without overlap, it is very easy to miss detections at the boundary. By actively reserving an overlap angle when selecting new anchor points, the surface control equipment ensures that the newly defined three-dimensional safe operating space partially overlaps with the previous safe operating space on the circumferential boundary. This guarantees that the main ROV repeatedly scans the overlapping area in two detection cycles, ensuring the continuity and integrity of the detection data.

[0044] The preset overlap range is a parameter pre-configured in the water surface control equipment. Its specific value is determined comprehensively based on factors such as the diameter of the object being measured, the working distance, and the field of view of the detection sensor, and is usually set between 5 and 10 degrees. If the overlap angle is too small, it will be difficult to effectively eliminate blind spots, while if it is too large, it will lead to a decrease in detection efficiency.

[0045] See Figure 4 , Figure 4 This is a schematic diagram of the process for constructing a flow field profile provided in an embodiment of this application, specifically including the following steps: S11. Acquire upper-layer flow data collected at the target depth by the Acoustic Doppler Current Profiler (ADCP) mounted on the ROV, and lower and intermediate-layer flow data collected by the ADCP mounted on the main ROV.

[0046] The surface control equipment, after reaching the preset target depth from the ROV, begins receiving and acquiring the basic flow data required to construct the flow field profile. This flow data originates from two different acquisition points. The first is the upper-layer flow data acquired by the Acoustic Doppler Current Profiler (ADCP) mounted on the ROV. This data covers the depth range from the current position of the ROV upwards to the water surface, including flow direction and velocity information for multiple depth layers within this range. The second is the lower and intermediate-layer flow data acquired by the ADCP mounted on the main ROV. This data covers the depth range from the current position of the main ROV downwards to the bottom. Since the main ROV is typically located closer to the object being measured than the ROV during the detection mission, its depth may be slightly deeper than the ROV's or near the same depth. Therefore, the lower and intermediate-layer flow data acquired by the main ROV effectively connects with the upper-layer flow data acquired by the ROV in the depth direction. The surface control equipment receives the two sets of water flow data synchronously through the communication channel integrated in the umbilical cable and caches them in the memory, providing raw data input for subsequent fusion processing.

[0047] In one example, the target depth of the ROV is set to 20 meters. The ADCP (Advanced Diffusion Pump) on the ROV emits acoustic pulses upwards, collecting 20 layers of flow data at 1-meter intervals from the 20-meter depth upwards to the surface. Each layer contains the flow direction angle and velocity value at that depth. Meanwhile, the main ROV operates at a depth of 25 meters, and its ADCP emits acoustic pulses downwards, collecting 15 layers of flow data from the 25-meter depth downwards to 40 meters below the bottom. The surface control equipment simultaneously receives the flow information from these 35 layers and temporarily stores them according to their respective depth labels, completing the acquisition of all the raw data required for constructing the flow field profile.

[0048] S12. The upper, lower and middle layer flow data are fused and processed to construct a three-dimensional flow profile model from the water surface to the bottom bed, which serves as the flow field profile.

[0049] The surface control equipment, after acquiring upper-layer and lower- and intermediate-layer flow data, begins to fuse these two sets of data. The core objective of this fusion process is to integrate discrete flow data from different sources, covering different depth ranges, into a continuous three-dimensional flow profile model covering the entire depth range from the surface to the bottom. The surface control equipment first aligns and stitches the two sets of data along the depth direction. For any narrow depth gaps that may exist between the two sets of data, an interpolation algorithm is used to smoothly fill them, eliminating data discontinuities. Simultaneously, for potential data conflicts in overlapping depth areas, a weighted average or optimal selection method is used for consistency processing. After completing the depth-direction stitching, the surface control equipment maps the flow vector data of each depth layer to a grid according to their horizontal spatial positions, constructing a complete model describing the flow direction and velocity distribution in three-dimensional space. This three-dimensional flow profile model, or flow field profile, can characterize the flow state at any spatial point within the currently probed water area, providing environmental basis for subsequent anchor point selection and safe space calculation.

[0050] Following the example in step S11, the surface control device stitches together the upper-layer flow data from 0 to 20 meters with the lower and intermediate-layer flow data from 25 to 40 meters. For the 5-meter depth gap between 20 and 25 meters, the surface control device uses a linear interpolation method to calculate estimated flow data for each layer at 21, 22, 23, and 24 meters based on the flow direction angle and velocity values ​​of the 20-meter and 25-meter layers. For any minor measurement differences that may exist between the two sets of data, the surface control device uses Kalman filtering for optimal estimation to ensure a smooth transition. Finally, the surface control device generates a flow field profile covering the entire depth range from 0 to 40 meters. The corresponding flow direction and velocity can be queried at any spatial coordinate point in this profile. When anchor point selection is required at a depth of 20 meters, the surface control device directly extracts the flow direction data at the 20-meter depth from this flow field profile for subsequent anchor point location calculations.

[0051] In this embodiment, the surface control device integrates discrete flow data acquired from the main ROV and two platforms at different depths from the ROV into a continuous flow field profile covering the entire water depth. This dual-platform complementary acquisition and fusion construction method overcomes the limitation that the ADCP carried by a single ROV can only cover a partial depth range, enabling the surface control device to acquire complete flow distribution information from the water surface to the bottom, providing an accurate environmental perception basis for subsequent anchor point deployment and safe space decision-making at different depths.

[0052] See Figure 5 , Figure 5 This is a schematic diagram of the process for determining the anchor point position provided in an embodiment of this application, which specifically includes the following steps: S21. Obtain the direction of water flow from the depth of the ROV in the flow field profile, as well as the position information of the object being measured.

[0053] In this process, the surface control equipment, based on the constructed flow field profile, begins the first step of anchor point selection: acquiring the input data required for decision-making. The surface control equipment extracts the water flow direction data corresponding to the target depth currently occupied by the ROV from the flow field profile. This data characterizes the horizontal direction of the water flow at that depth plane. Simultaneously, the surface control equipment retrieves the spatial position information of the object being measured. The position information of the object can be obtained through pre-stored engineering drawing coordinates, underwater positioning system calibration results, or previous survey data, typically existing as a set of three-dimensional coordinates of the object's central axis or outer contour surface. The surface control equipment loads the aforementioned water flow direction data and the object's position information into the same spatial coordinate system, providing a unified spatial reference datum for subsequent candidate area delineation and point selection calculations.

[0054] In one example, the ROV is located at a depth of 20 meters underwater. The surface control equipment queries the flow field profile to determine the horizontal flow direction at the 20-meter depth layer. The query result is a direction of 30 degrees north of east, meaning the water flows from 30 degrees south of west to 30 degrees north of east, with a flow velocity of 0.5 meters per second. Simultaneously, the surface control equipment retrieves the location information of the measured pile from pre-stored data. This location information indicates that the pile is a cylindrical structure, with its central axis projected onto the horizontal plane as the origin of the coordinate system, and the outer surface radius of the pile is 1.5 meters. The surface control equipment places the 30-degree north of east flow direction and the coordinates of the pile's central origin in the same plane coordinate system, completing the basic data preparation.

[0055] S22. Using the object being measured as a reference, the preset angle sector in the downstream direction of the water flow direction is determined as the candidate region.

[0056] After acquiring information about the water flow direction and the location of the object being measured, the surface control equipment begins to delineate the candidate area for anchor points. Using the horizontal projection of the object as a reference, the downstream side of the water flow direction is designated as the spatial orientation of the candidate area. The downstream area is a fan-shaped region extending to both sides of the water flow direction at preset angles. The size of these preset angles is pre-set based on actual hydrological conditions and safety redundancy requirements, typically ranging from 45 to 90 degrees, resulting in a total fan angle range of 90 to 180 degrees. The apex of this fan-shaped region is located at the object being measured, and the radius of the fan extends downstream. Within this fan-shaped region, all points at a distance equal to the monitoring distance from the surface of the object forming an arc segment. Each point on this arc segment is a candidate point, collectively constituting the candidate area for anchor points.

[0057] In one example, see Figure 6 The schematic diagram of the anchor point candidate area shows that the water flow direction is southward, meaning the downstream direction is relative to the south, southeast, or southwest side of the object being measured. The surface control equipment can use the center of the anchor pile as a reference, extending 60 degrees to the left and right along the southward direction as the center line, forming a fan-shaped candidate area covering a total angle of 120 degrees, from 60 degrees east of south, through due south, to 60 degrees west of south. Within this fan-shaped area, points at a distance of 10 meters from the outer surface of the anchor pile constitute an arc. The monitoring distance refers to the pre-set spatial distance that should be maintained from the ROV anchor point to the surface of the object being measured; the value of 10 meters ensures a safe position for the ROV outside the anchor pile's disturbance zone. Multiple candidate points are distributed along this arc, each satisfying the condition of being 10 meters from the surface of the object being measured. This is merely an example; it should be understood that in actual situations, this candidate area is not limited to 120 degrees.

[0058] S23. Within the candidate area, for each candidate point that satisfies the condition that the distance from the object being measured is equal to the monitoring distance, calculate the drift tendency of the umbilical cable away from the object being measured under the action of the water flow direction.

[0059] In this process, after determining the candidate area, the surface control equipment calculates the drift trend for each candidate point within that area. The drift trend quantifies the tendency of the umbilical cable connecting the main and auxiliary ROVs to drift away from the object under the influence of water flow when the ROV is suspended at a candidate point. The surface control equipment uses the candidate point as the spatial location of the auxiliary ROV, combining the water flow direction and velocity at that depth, the known physical characteristics of the umbilical cable, and the shape and position of the object under test to simulate the spatial morphology of the umbilical cable under the influence of water flow. During the calculation, the surface control equipment discretizes the umbilical cable into several micro-segments, applies a water flow drag force to each micro-segment, and considers the tension and gravity within the umbilical cable. It then uses mechanical equilibrium equations to solve for the spatial orientation of the umbilical cable extending from the candidate point towards the surface. Finally, the surface control equipment analyzes the degree of deviation of this spatial orientation relative to the object under test, using the angle or distance deviation between the drift direction projected onto the horizontal plane and the direction pointing towards the object under test as a quantitative indicator of the drift trend. The above calculation is performed on each candidate point within the candidate region to obtain the drift trend value corresponding to each candidate point.

[0060] In one example, there are two typical candidate points on the candidate arc segment, denoted as candidate point A and candidate point B. Candidate point A is located at 30 degrees south of east, and candidate point B is located at 60 degrees south of east. The surface control equipment performs simulation calculations for candidate point A, assuming the ROV is hovering at this point, with the umbilical cable extending upwards in an arc shape under the influence of water flow. The calculation results show that the projection direction of this arc on the horizontal plane is generally biased away from the pile, with a drift trend score of 0.8. The score ranges from 0 to 1, with a higher score indicating a stronger tendency to deviate from the measured object. The same simulation calculation is performed for candidate point B. Because candidate point B is closer to the edge of the candidate fan-shaped area, the flow around the pile causes the umbilical cable to have a slight tendency to swing back towards the pile, with a drift trend score of 0.6. The surface control equipment performs the above calculations for all discrete candidate points on the candidate arc segment one by one to obtain the drift trend score for each point.

[0061] S24. Select the candidate point with the largest drift trend as the anchor point.

[0062] After obtaining the drift trend values ​​of all candidate points within the candidate area, the surface control equipment compares the magnitudes of these drift trend values ​​to determine the final anchor point selection. The equipment sorts the drift trend values ​​of each candidate point from largest to smallest, identifying the candidate point with the largest drift trend value. The spatial location corresponding to this candidate point represents the position where, under the current water flow conditions, the umbilical cable is most likely to move away from the measured object. Deploying the anchor point at this location minimizes the risk of the umbilical cable being pressed towards or entangled by the water flow. The surface control equipment then determines the three-dimensional spatial coordinates of this candidate point as the anchor point coordinates, completing the anchor point selection process.

[0063] In one example, following the calculation results of step S23, candidate point A has a drift trend score of 0.8, candidate point B has a score of 0.6, and the scores of the remaining candidate points on the arc segment are all between 0.5 and 0.7. The score of 0.8 for candidate point A is the maximum among all candidate points. Based on this, the surface control equipment determines candidate point A as the optimal anchor point and records its three-dimensional coordinates as anchor point coordinates. These coordinates are located at a depth of 20 meters, an azimuth angle of 60 degrees east of north relative to the center of the pile, and a distance of 10 meters from the surface of the pile. Subsequently, the surface control equipment will send a hovering command containing these anchor point coordinates to the ROV, controlling the ROV to move to this point and maintain its position.

[0064] It is understandable that the anchor point position determined by the above steps should be the initial anchor point of the ROV at the set depth.

[0065] In this embodiment, the surface control equipment realizes a complete decision-making closed loop, starting from water flow environment data and object position information, through candidate area delineation, drift trend quantification calculation, and optimal anchor point selection. This method transforms the criteria for anchor point selection from manual experience into quantifiable drift trend indicators. By comparing points within the candidate area, it automatically selects the position where the umbilical cable's tendency to deviate from the measured object is strongest as the anchor point. This minimizes the risk of the umbilical cable entanglement with the pile under complex water flow conditions, providing a reliable positioning benchmark for the subsequent safe operation of the main ROV.

[0066] See Figure 7 As shown, Figure 7 This is a flowchart illustrating the process of constructing a three-dimensional safe working space according to an embodiment of this application, specifically including the following steps: S31. Based on the water flow conditions, confirm the safe distance between the main ROV and the slave ROV.

[0067] After the surface control equipment establishes its anchor point from the ROV, it begins by determining the three-dimensional safe operating space for the master ROV. The first step is to confirm the safe distance that should be maintained between the master and slave ROVs. This safe distance is one of the cooperative operation constraint parameters, and its function is to ensure that the master and slave ROVs maintain sufficient space at any time during operation to prevent collisions or umbilical cable entanglement.

[0068] S32. Determine the spatial range with the anchor point as the center of the sphere and the cable length as the radius.

[0069] After confirming the safe distance, the surface control equipment begins to construct the maximum spatial boundary for the main ROV's operations. Using the spatial coordinates of the slave ROV anchor point determined in step S2 as the center and the length of the umbilical cable connecting the main and slave ROVs as the radius, the surface control equipment defines a complete spherical spatial range in three-dimensional space. This spherical spatial range represents the set of all theoretically reachable locations of the main ROV under the physical cable length constraint. The umbilical cable length is a pre-set parameter stored in the surface control equipment, determining the maximum permissible distance between the main and slave ROVs. This spherical spatial range is the fundamental geometry for all subsequent spatial constraints, and the final boundary of the three-dimensional safe operating space will be completely contained within this sphere.

[0070] For example, suppose the ROV anchor point is located at 0 degrees North latitude, 0 degrees East longitude, and a depth of 20 meters, with an umbilical cable length of 50 meters. The surface control equipment generates a virtual sphere with this anchor point as the center and a radius of 50 meters. This sphere encompasses the entire three-dimensional space within a 50-meter radius of the anchor point, and the straight-line distance from any point within the sphere to the anchor point does not exceed 50 meters. The main ROV, limited by the physical connection of the umbilical cable, cannot actually reach locations beyond the outer surface of this sphere.

[0071] S33. Remove the area from the spatial range whose depth distance from the anchor point is less than the safe distance to obtain the remaining space.

[0072] After determining the spherical space range, the surface control equipment begins to progressively constrain this range. The first constraint is to eliminate areas that do not meet the safe distance requirements. Using the ROV anchor point as a reference, the surface control equipment measures the distance along the depth direction (vertical direction). All spatial points within the spherical space whose depth difference from the anchor point is less than the safe distance confirmed in step S31 are marked and eliminated. This elimination operation means excluding these points from the usable space; the main ROV must not enter the eliminated area. After elimination, the spherical space range becomes a remaining space with a hollowed-out strip-shaped area in the depth direction. This constraint ensures that the main ROV and the slave ROV always maintain sufficient vertical spacing, avoiding the risk of collision due to insufficient depth difference or the risk of attitude loss due to excessively short cables.

[0073] For example, following steps S31 and S32, the anchor point depth is 20 meters, and the confirmed safe distance is 5 meters. Within a spherical space with a radius of 50 meters, the surface control equipment marks all points with depths between 15 and 25 meters (i.e., depth differences from the anchor point less than 5 meters) as a rejection zone. This rejection zone is a horizontal slice with a thickness of 10 meters inside the sphere. After rejection, the remaining space on the sphere is divided into upper and lower parts: the upper part is the area with a depth less than 15 meters, and the lower part is the area with a depth greater than 25 meters. The main ROV can only operate in one of these two depth ranges.

[0074] S34. In the remaining space, constrain the spatial distance between the main ROV and the surface of the object being measured to be equal to the working distance, and use the set of spatial points that satisfy the constraint conditions as the three-dimensional safe working space.

[0075] After obtaining the remaining space, the surface control equipment applies a final constraint: the spatial distance between the main ROV and the surface of the object being measured must equal the working distance. Within the remaining space, the surface control equipment searches for all spatial points that satisfy the condition that the closest distance to the object's surface is exactly equal to the working distance. This constraint ensures that the main ROV maintains a constant detection distance from the object during operation, satisfying both the imaging requirements of the detection sensors and preventing collisions between the main ROV and the object. All spatial points satisfying this constraint constitute a set of spatial points, which is the three-dimensional safe operating space. Geometrically, this space typically appears as a portion of an equidistant curved surface parallel to the object's surface, truncated within the boundary of the remaining space. The surface control equipment records this set of spatial points as the boundary of the three-dimensional safe operating space permitted for the main ROV's current operating cycle.

[0076] In one example, the working distance is set to 2 meters. After step S33, in the remaining space below the sphere with a depth greater than 25 meters, the surface control equipment searches for all spatial points exactly 2 meters from the pile surface. These points form an equidistant curved surface surrounding the pile surface at a distance of 2 meters. The intersection of this equidistant curved surface and the remaining space constitutes the final three-dimensional safe working space. This space is limited to a depth of 25 to 50 meters, a circumferential dimension downstream of the current anchor point, and a radial dimension exactly 2 meters from the pile surface. The surface control equipment records the coordinate boundaries of this space, and subsequent detection path commands sent to the main ROV will be strictly limited to this space.

[0077] In this embodiment, the surface control equipment integrates multiple constraints from different sources into a computable geometric solution process. This process progressively compresses the available space, starting from the ROV anchor point as the spatial origin, using the umbilical cable length as the upper radius limit, the adaptive safety distance for water flow as the collision avoidance constraint, and the working distance as the operational accuracy constraint, ultimately obtaining the three-dimensional safe operating space of the main ROV. This layered constraint and step-by-step solution approach transforms the delineation of safe space under complex hydrological conditions from relying on operator experience to automated quantitative calculation based on real-time data and preset parameters. This ensures the accuracy of the main ROV's detection operations and eliminates the safety hazards of cable entanglement and ROV collisions from a fundamental mechanism.

[0078] Furthermore, before determining the three-dimensional safe operating space of the main ROV, the surface control equipment needs to first confirm the applicable safe distance between the main and slave ROVs for this round of operations. The safe distance is not determined using a single fixed value, but rather by adaptively selecting between two modes based on real-time water flow conditions.

[0079] The surface control equipment first acquires the water flow direction at the depth of the ROV anchor point and the water flow direction at the current depth of the main ROV. Both of these water flow direction data are derived from the flow field profile constructed in step S1. The surface control equipment compares these two directions and calculates the angle between them. Simultaneously, the surface control equipment also checks for significant differences in the water flow direction from adjacent depth layers above and below the ROV anchor point, i.e., whether water flow shear exists. Water flow shear can be determined by comparing whether the angle between the water flow directions at a certain distance above and below the anchor point exceeds a preset threshold.

[0080] See Figure 8The diagram illustrates the first safety distance. When the surface control equipment determines that the water flow direction at the depth of the master ROV is consistent with the water flow direction at the depth of the slave ROV anchor point, and there is no significant water flow shear on either side of the ROV, the surface control equipment sets the safety distance to the preset first safety distance D3. D1 represents the working distance, L1 represents the length of the umbilical cable, and D2 represents the monitoring distance. The first safety distance is a fixed parameter pre-stored in the surface control equipment, and its physical meaning is the minimum allowable difference in depth between the master and slave ROVs. In this case, the water flow conditions are relatively simple, and the attitude of the umbilical cable is mainly affected by the dragging effect of the water flow in one direction. The bending degree of the cable in the depth direction is limited, and a smaller safety distance is sufficient to ensure that there is no collision or entanglement between the master and slave ROVs.

[0081] When the surface control equipment determines that the water flow direction at the depths of the main ROV and the slave ROV is inconsistent, or that there is a significant shear in the water flow direction above and below the slave ROV, the water flow conditions become complex. Under these complex water flow conditions, the umbilical cable may be pushed by water flow from different directions at different depths, forming a bent, twisted, or even S-shaped posture. The actual shape of the cable between the main and slave ROVs differs significantly from the catenary shape under simple water flow conditions. If the first safety distance D3 is continued to be used at this time, there is a risk that the cable will become entangled in the slave ROV or that the main ROV will collide with the slave ROV. Therefore, the surface control equipment activates the second safety distance. The second safety distance is calculated in real time by the surface control equipment using a geometric model based on the umbilical cable length, monitoring distance, and working distance, and its value is greater than the first safety distance. The physical meaning of the second safety distance is the minimum straight-line distance required under extreme turbulent water flow conditions to ensure that no part of the cable contacts the surface of the measured object and that there is no collision between the main and slave ROVs. After adopting the second safety distance, the boundary of the three-dimensional safe working space will shrink accordingly, providing a more conservative and safer operating constraint for the main ROV.

[0082] Optional, see Figure 9 The diagram illustrates the second safety distance. Under complex water flow conditions, the surface control equipment needs to calculate the second safety distance D4 to replace the preset first safety distance as the minimum safety distance constraint between the master and slave ROVs. The calculation of D4 is based on a limit safety verification model, which simulates the most unfavorable spatial attitude of the umbilical cable that may be caused by turbulent water flow, and solves the straight-line distance between the master and slave ROVs under this attitude.

[0083] The extreme safety verification model is constructed based on the following assumptions. Under turbulent water flow, the umbilical cable connecting the main ROV and the slave ROV no longer exhibits a smooth catenary shape, but is pushed by water flow in different directions to form a broken line. This broken line consists of two straight segments connected end to end. One end of the first segment connects to the slave ROV, and the other end is the break point. This segment is perpendicular to the surface of the object being measured, and its length is equal to the monitoring distance D2 of the slave ROV. One end of the second segment connects to the main ROV, and the other end is the same break point. This segment is also perpendicular to the surface of the object being measured, and its length is equal to the working distance D1 of the main ROV. The total length of the two broken lines is exactly equal to the length L1 of the umbilical cable between the main and slave ROVs. The break point is located exactly on the surface of the object being measured.

[0084] This geometric arrangement represents the extreme state of umbilical cable entanglement risk. The inflection point is located on the surface of the object being measured, meaning that a segment of the cable has already come into contact with the object. If the cable deviates further, entanglement will occur. The two inflection lines are perpendicular to the surface of the object being measured, meaning that the distances from the ROV and the main ROV to the object being measured are precisely constrained by the monitoring distance and the working distance, respectively. Under this extreme geometric relationship, the straight-line distance between the spatial position of the main ROV and the anchor point position of the ROV is the second safety distance D4, calculated using the following formula: .

[0085] Understandably, in actual underwater operations, the second safety distance D4 should be greater than the first safety distance D3.

[0086] Please see Figure 10 This is a structural block diagram of a cooperative underwater object detection device provided in an embodiment of this application. The cooperative detection device includes: Module 1001 is used to control the ROV to descend to a preset target depth and to construct a flow field profile based on the stratified water flow data collected at different depths from the main ROV and the slave ROV. The selected module 1002 is used to select a point at a monitoring distance from the object being measured as the anchor point of the ROV in the downstream region relative to the object being measured, based on the water flow direction at the depth of the ROV in the flow field profile, and control the ROV to hover at the anchor point. The determination module 1003 is used to determine the current three-dimensional safe operating space of the main ROV based on the collaborative operation constraint parameters and the real-time water flow conditions. The collaborative operation constraint parameters include at least the following: the cable length between the main ROV and the slave ROV, the monitoring distance, and the working distance between the main ROV and the object being measured. The cable length, monitoring distance, and working distance are preset. The monitoring distance is greater than the working distance. The control module 1004 is used to control the main ROV to perform zone detection on the object under test at a working distance within the three-dimensional safe working space.

[0087] For further details regarding the implementation of the above-mentioned technical solutions by each module in the collaborative underwater object detection device, please refer to the description in the collaborative mapping method for underwater objects provided in the above-mentioned embodiments of the invention, which will not be repeated here.

[0088] See Figure 11 This is a structural block diagram of a surface control device provided in an embodiment of this application. The surface control device includes a processor, a memory, a network interface, and a database connected via a system bus. The processor of the surface control device provides computing and control capabilities. The memory of the surface control device includes non-volatile and / or volatile storage media and internal memory. The non-volatile storage media stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface of the surface control device is used for communication with external clients via a network connection. When the computer program is executed by the processor, it implements the functions or steps of a collaborative mapping method for underwater objects.

[0089] In one embodiment, a surface control device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement... Figure 2 The method shown can be referred to for details. Figure 2 As shown, it will not be elaborated further here.

[0090] In one embodiment, a computer-readable storage medium is provided that stores a computer program, which is loaded and executed by a processor as described above. Figure 2 The method steps of the illustrated embodiment can be found in the following documentation for detailed execution. Figure 2 The specific details of the illustrated embodiments will not be elaborated here.

[0091] It should be noted that the functions or steps that the computer-readable storage medium or water surface control device can achieve are described in the relevant descriptions of the server side and client side in the foregoing method embodiments. To avoid repetition, they will not be described one by one here.

[0092] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0093] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0094] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A cooperative detection method for underwater objects, characterized in that, The method is applied to surface control equipment, which is communicatively connected to a master ROV and a slave ROV, and the master ROV and the slave ROV are connected to the same umbilical cable; the method includes: The ROV is controlled to descend to a preset target depth, and a flow field profile is constructed based on the stratified water flow data collected at different depths by the main ROV and the secondary ROV. Based on the water flow direction at the depth of the ROV in the flow field profile, a point at a monitoring distance from the object being measured is selected as the anchor point of the ROV in the downstream region relative to the object being measured, and the ROV is controlled to hover at the anchor point. Based on the collaborative operation constraint parameters and the real-time water flow conditions, the current three-dimensional safe operating space of the main ROV is determined; wherein, the collaborative operation constraint parameters include at least: the cable length between the main ROV and the slave ROV, the monitoring distance, and the working distance between the main ROV and the object under test; the cable length, monitoring distance, and working distance are preset; the monitoring distance is greater than the working distance; The main ROV is controlled to perform zoned detection of the object under test within the three-dimensional safe working space at the working distance.

2. The method according to claim 1, characterized in that, The method further includes: In response to the completion of the current partition detection, the anchor point from the ROV is updated to the next position along the circumference of the object under test, and the three-dimensional safe working space of the main ROV is redefined to perform the next partition detection. This process is repeated until the full circumferential detection of the object under test at the current depth is completed. After completing the full circumferential detection at the current depth of the object under test, the target depth from the ROV is adjusted, and the steps of selecting the anchor point, determining the three-dimensional safe working space, and cyclic detection are re-executed to achieve detection of different depth segments of the object under test.

3. The method according to claim 1, characterized in that, Based on the water flow direction at the depth of the ROV in the flow field profile, selecting a point at a monitoring distance from the measured object as the anchor point of the ROV within the downstream region relative to the measured object includes: Obtain the direction of water flow from the depth of the ROV in the flow field profile, as well as the position information of the object under test; Using the object under test as a reference, the preset angle sector in the downstream direction of the water flow direction is determined as the candidate region; Within the candidate area, for each candidate point that satisfies the condition that the distance from the object being measured is equal to the monitoring distance, the drift tendency of the umbilical cable away from the object being measured under the action of the water flow direction is calculated. The candidate point with the largest drift trend is selected as the anchor point.

4. The method according to claim 1, characterized in that, The collaborative operation constraint parameters also include the safe distance between the master ROV and the slave ROV; The step of determining the current three-dimensional safe operating space of the main ROV based on collaborative operation constraint parameters and real-time water flow conditions includes: Based on the water flow conditions, confirm the safe distance between the main ROV and the slave ROV; The spatial range is determined with the anchor point as the center of the sphere and the cable length as the radius. The remaining space is obtained by removing areas from the space that are less than the safe distance in the depth direction from the anchor point; In the remaining space, the spatial distance between the main ROV and the surface of the object under test is constrained to be equal to the working distance, and the set of spatial points that satisfy the constraint condition is taken as the three-dimensional safe working space.

5. The method according to claim 4, characterized in that, The step of determining the safe distance between the main ROV and the slave ROV based on the water flow conditions includes: Determine the direction of water flow at the depths of the main ROV and the secondary ROV based on the water flow conditions. When the main ROV and the auxiliary ROV are in the same direction of water flow at their respective depths, the safety distance is set to a preset first safety distance; When the water flow direction at the depth of the main ROV is inconsistent with that at the depth of the auxiliary ROV, or when the water flow direction on the upper and lower sides of the auxiliary ROV is inconsistent, a second safety distance is calculated based on the cable length, the monitoring distance, and the working distance; the second safety distance is greater than the first safety distance.

6. The method according to claim 5, characterized in that, When the water flow direction at the depth of the main ROV is inconsistent with that at the depth of the auxiliary ROV, or when the water flow directions on the upper and lower sides of the auxiliary ROV are inconsistent, the formula for calculating the second safety distance is: ； Wherein, D4 is the second safety distance, D2 is the monitoring distance, D1 is the working distance, and L1 is the cable length.

7. The method according to claim 2, characterized in that, In the step of updating the anchor point from the ROV to the next position along the circumference of the object being measured, the depth of the anchor point and the monitoring distance are kept unchanged, and the anchor point is moved at a preset angle interval in a clockwise or counterclockwise direction to form a new anchor point; wherein, the three-dimensional safe working space of the main ROV corresponding to two adjacent detection cycles has a preset angle overlap range in the circumferential angle.

8. A cooperative detection device for underwater objects, characterized in that, The device includes: The module is used to control the ROV to descend to a preset target depth and to construct a flow field profile based on the stratified water flow data collected at different depths from the main ROV and the secondary ROV. The selection module is used to select a point at a monitoring distance from the object being measured as the anchor point of the ROV in the downstream region relative to the object being measured, based on the water flow direction at the depth of the ROV in the flow field profile, and to control the ROV to hover at the anchor point. The determination module is used to determine the current three-dimensional safe operating space of the main ROV based on collaborative operation constraint parameters and real-time water flow conditions; wherein, the collaborative operation constraint parameters include at least: the cable length between the main ROV and the slave ROV, the monitoring distance, and the working distance between the main ROV and the object under test; the cable length, monitoring distance, and working distance are preset; the monitoring distance is greater than the working distance; The control module is used to control the main ROV to perform zonal detection of the object under test within the three-dimensional safe working space at the working distance.

9. A water surface control device, characterized in that, The surface control device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the collaborative mapping method for underwater objects as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that is loaded by a processor and executes the steps of the collaborative mapping method for underwater objects as described in any one of claims 1 to 7.

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