A multi-aquatic robot seabed area cooperative search method

Abstract

The application provides a kind of multi-underwater robot seabed area cooperative search method, it is related to seabed target autonomous search technical field.The method comprises: according to communication distance constraint, task area is divided into multiple sub-regions and sets electronic fence;In each sub-region, parallel survey line is generated, and survey line task is allocated to subordinate AUV according to the principle of modulo, to realize equal load division of labor;Each subordinate AUV executes task and transmits target information to master control platform;Master control platform assesses the progress state of each sub-region based on target information, dynamically schedules subordinate AUV cooperative work;When target confidence reaches the standard, insert review evidence task;For communication anomaly, border crossing or low energy, etc.Abnormal, emergency strategy is executed and unified re-planning after anomaly recovery.The application realizes the balance of complete coverage, continuous operation and target accurate search in large range of sea area through the cooperative work framework under the communication constraint, improves the operation efficiency and reliability.

Description

Technical Field

[0001] This application relates to the field of autonomous search technology for seabed targets, and in particular to a method for collaborative search of seabed areas by multiple underwater robots. Background Technology

[0002] Autonomous search for seabed targets is a crucial link in deep-sea space development, safety protection, and infrastructure operation and maintenance. A typical mission chain includes wide-area search and pre-verification confirmation. Target types include both seabed pipelines such as cables and lines, as well as point objects such as wrecked debris and lost targets. The operating areas are often large-scale, with complex terrain and variable environments. Unlike air and ground scenarios, underwater operations are often conducted under conditions where GPS (Global Positioning System) is unavailable and acoustic propagation is limited: underwater acoustic links have low bandwidth, high latency, are prone to interruption, and have a stable communication range of only kilometers. This poses significant challenges to information synchronization, collaborative control, and mission replanning among multiple AUVs (Autonomous Underwater Vehicles). At the same time, inertial navigation and DVL (Doppler Velocity Log) systems are prone to drift accumulation or loss of lock-on under long-duration and complex seabed conditions, making it difficult to guarantee coverage paths and target positioning accuracy in the long term.

[0003] Existing technical approaches mainly fall into two categories: one is single-AUV lawnmower-style full-coverage search, which has the advantage of simple implementation but is inefficient in wide-area searches; the other is multi-AUV parallel operation, but often treats multiple machines as independent single-machine repetitions, lacking systematic management of communication reachability, positioning errors, and operation organization, which easily leads to problems such as coverage redundancy and blind spots, unquantifiable progress, and insignificant collaborative benefits. Some studies have introduced centralized global planning or distributed consistency control, but the former relies on stable high-frequency links, making it difficult to adapt to weak communication scenarios; the latter, under low bandwidth and asynchronous packet loss conditions, makes it difficult to guarantee collaborative stability and task convergence speed in engineering.

[0004] At the task management level, existing solutions generally lack region division based on communication constraints and initial task allocation mechanisms with low communication load. There is a lack of unified progress metrics and interpretable collaboration strategies among multiple AUVs. When events such as partial completion, sudden target verification, individual disconnection, or power alarm occur, the system's dynamic scheduling and emergency takeover mechanisms are inadequate, making it difficult to quickly recover without interrupting the main task. Furthermore, target discovery and path generation are often decoupled, lacking confidence-based verification insertion and job priority adjustment. Regarding status monitoring, inconsistent data fields and insufficient heartbeat and health monitoring affect the reliability of coverage assessment, trajectory reproduction, and task review.

[0005] In summary, the engineering realities of weak underwater communication and positioning errors make traditional single-machine coverage or loosely coupled parallel methods insufficient to meet the dual requirements of wide-area efficient search and real-time verification. Therefore, this technical problem urgently needs to be solved. Summary of the Invention

[0006] In view of the above problems, this application is proposed to provide a method for cooperative search of seabed areas by multiple underwater robots to overcome or at least partially solve the above problems. The technical solution is as follows: Firstly, a method for collaborative seabed area search by multiple underwater robots is provided, the method comprising: Based on the reachable distance of communication Divide the task region S into multiple sub-regions to generate a set of sub-regions. and traversal sequence Set up electronic fences for each sub-area ; Based on the preset survey line spacing Generate a set of parallel survey lines for each sub-region Based on the total number of parallel survey lines in each sub-region The number of subordinate AUVs and the assignment of survey line task sequences to each subordinate AUV based on the modulus principle; Each subordinate AUV performs the assigned survey line task and transmits target information to the main control platform according to the preset protocol; The main control platform evaluates the execution status of each sub-region based on the target information transmitted by each slave AUV; the execution status includes in progress, partially completed, and completed. When there is a first sub-region where the execution status is partially completed, an assistant is selected from all subordinate AUVs in the first sub-region that are in an idle state based on a preset cost function, and the assistant is assigned an unexecuted survey line task. If a second sub-region exists with a completed execution state, a third sub-region is selected from all sub-regions with non-complete execution states based on the nearest boundary principle. And in the third sub-region Select the optimal entry point on the boundary based on the nearest point principle. Generate the path from the end point of the second sub-region to the optimal entry point. The connection path; wherein, the connection path should be within the communication reach distance. and electronic fence Within the range; All subordinate AUVs in the second sub-region are scheduled to move along the connecting path to the third sub-region. The third sub-region Unexecuted survey line tasks in the parallel survey line set are remapped to the third sub-region according to the modulus rules. Currently, all subordinate AUVs are performing a remapped survey line task. When the target confidence level in the target state transmitted by the first subordinate AUV is greater than or equal to a preset threshold, the first subordinate AUV is scheduled to perform target verification or evidence collection actions. After the actions are completed, the first subordinate AUV continues to perform the line measurement task. There are issues with the second subordinate AUV communication, equipment malfunction, and location outside the electronic fence. If the energy level falls below the safety threshold, an emergency strategy is triggered; once the second slave AUV returns to normal, the main control platform will re-plan the task.

[0007] In one possible implementation, the survey line spacing is preset. satisfy: (1) In equation (1), This refers to the effective field of view of the sensor mounted on the AUV. As a preset redundancy coefficient, and ; Total number of survey lines satisfy: (2) In equation (2), is the geometric scale of the sub-region.

[0008] In one possible implementation, it is based on the total number of survey lines in the set of parallel survey lines within each sub-region. The number of subordinate AUVs is determined, and a survey line task sequence is assigned to each subordinate AUV according to the modulus principle, including: Get the total number of subordinate AUVs in the fourth sub-region ; Assign a sequential number to each subordinate AUV in the fourth sub-region; For the sequential number is Subordinate AUVs, survey line mission sequence satisfy: (3) In equation (3), Greater than or equal to 1 and less than or equal to .

[0009] In one possible implementation, the target information includes the subordinate AUV identifier AUV_ID, timestamp Time, sub-region identifier Region_ID, subordinate AUV status Stateflag, task progress process, position, error message err, remaining energy Restpower, heartbeat information Heartbeat and target status Target_State. For the i-th subordinate AUV, satisfy: (4) In equation (4), Let be the total measurement line length of the i-th subordinate AUV. Let be the total length of the survey line completed by the i-th subordinate AUV.

[0010] In one possible implementation, the master control platform obtains the time of the third subordinate AUV's most recent heartbeat report. If the current time t and The difference is greater than the preset heartbeat timeout threshold. If so, the main control platform determines that the third subordinate AUV communication is abnormal.

[0011] In one possible implementation, the master control platform evaluates the execution status of each sub-region based on the target information transmitted by each slave AUV, including: The main control platform calculates the completion status of all survey line tasks within the same sub-region based on the target information reported by all subordinate AUVs. If all subordinate AUVs within the same sub-region are performing surveying tasks, then the execution status of the sub-region is determined to be "in execution". If within the same sub-region there are both subordinate AUVs performing survey tasks and subordinate AUVs that have completed survey tasks and are idle, then the execution status of the sub-region is determined to be partially completed. If all subordinate AUVs within the same sub-region have completed their survey tasks and are in an idle state, then the execution status of the sub-region is determined to be completed.

[0012] In one possible implementation, an assistant is selected from all idle subordinate AUVs in the first sub-region based on a preset cost function, including: The main control platform identifies all idle subordinate AUVs within the first sub-region, forming a candidate assisting AUV set; For each slave in the candidate assist AUV set Calculate the assistance cost : (5) In equation (5), for The distance to the unmeasured line segment for Remaining energy For the weighting factor; Main control platform selects assistance cost smallest subordinate As an facilitator.

[0013] In one possible implementation, a third sub-region is selected from all sub-regions whose execution state is not yet complete, based on the nearest boundary principle. And in the third sub-region Select the optimal entry point on the boundary based on the nearest point principle. ,include: The main control platform groups all sub-regions whose execution status is not yet complete into a set of incomplete sub-regions. ; satisfy: (6) In equation (6), For system reference pose; Optimal entry point satisfy: (7) In equation (7), For the third sub-region The set of boundary points.

[0014] In one possible implementation, the first subordinate AUV is scheduled to perform target review or forensic actions, including: The main control platform determines the target type in the target status reported by the first subordinate AUV; If the target type is a subsea pipeline, a first verification path is generated along the local tangent of the target, and the first subordinate AUV is controlled to navigate along the first verification path, while constraining the navigation depth and height above the bottom. If the target type is a point object, a second core path is generated around the target or distributed in a star shape, and the first subordinate AUV is controlled to navigate along the second core path; After the review is completed, the target dictionary D is updated; the target dictionary D includes target type, target location, target scale, and updated target confidence level.

[0015] By employing the above technical solution, the multi-submarine robot seabed area collaborative search method provided in this application includes: dividing the task area into multiple sub-regions and setting up electronic fences based on communication distance constraints; generating parallel survey lines in each sub-region and assigning survey line tasks to subordinate AUVs according to the modulus principle to achieve equal workload division; each subordinate AUV executing tasks and transmitting target information to the main control platform; the main control platform evaluating the progress status of each sub-region based on the target information and dynamically scheduling the collaborative work of subordinate AUVs; inserting verification and evidence collection tasks when the target confidence level meets the standard; and implementing emergency strategies for anomalies such as communication interruption, boundary crossing, or low energy, and uniformly replanning after the anomaly is recovered. This application, through a collaborative operation framework under communication constraints, achieves a balance between complete coverage, continuous operation, and accurate target search in a large sea area, improving operational efficiency and reliability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below.

[0017] Figure 1 A flowchart of the multi-underwater robot cooperative search method for seabed areas provided in an embodiment of this application is shown; Figure 2 A flowchart of a multi-underwater robot cooperative search method for seabed areas provided in a specific embodiment of this application is shown; Figure 3 The timing link diagram of the multi-underwater robot seabed area cooperative search method provided in a specific embodiment of this application is shown; Figure 4 This illustration shows a wide-area region partitioning strategy for a multi-underwater robot seabed collaborative search method provided in a specific embodiment of this application; Figure 5 This illustration shows a schematic diagram of the comb-shaped survey line layout for the multi-underwater robot seabed area cooperative search method provided in a specific embodiment of this application; Figure 6 This illustration shows a survey line allocation diagram of the multi-underwater robot seabed area cooperative search method provided in a specific embodiment of this application; Figure 7 This illustration shows a schematic diagram of the execution of a subordinate AUV task in the multi-underwater robot seabed area cooperative search method provided in a specific embodiment of this application; Figure 8 This illustration shows a schematic diagram of the same-area cooperative search scheduling of the multi-underwater robot seabed area cooperative search method provided in a specific embodiment of this application; Figure 9 This illustration shows a cross-regional collaborative search scheduling diagram of the multi-underwater robot seabed area collaborative search method provided in a specific embodiment of this application. Detailed Implementation

[0018] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0019] It should be noted that the terms "first," "second," etc., in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the term "comprising" and its variations should be interpreted as open-ended terms meaning "including but not limited to."

[0020] Analysis revealed that underwater operations face core constraints, including GPS unavailability, limited underwater acoustic communication, and susceptibility to positioning errors. Furthermore, the operational areas are large-scale and the environment is complex. Existing seabed target search technologies suffer from insufficient efficiency with single-AUV operations and a lack of systematic management of communication, positioning, and operational organization for multi-AUV parallel operations. Additionally, issues such as unquantifiable progress, inadequate collaborative scheduling, and insufficient emergency fault tolerance exist. These problems are key reasons for the low efficiency, poor coverage, and insufficient mission continuity in seabed target search operations, and also point the way for technological optimization in collaborative seabed target search.

[0021] To address the aforementioned technical problems, this application provides a method for collaborative seabed area search using multiple underwater robots, such as... Figure 1 As shown, the multi-underwater robot cooperative search method for seabed areas may include the following steps S101 to S109: Step S101, based on the communication reach distance Divide the task region S into multiple sub-regions to generate a set of sub-regions. and traversal sequence Set up electronic fences for each sub-area .

[0022] In this step, the communication reach distance This refers to the maximum distance threshold that enables stable and reliable underwater acoustic communication between the master control platform and the subordinate AUVs, and is a fundamental constraint on the division of the entire mission area; the mission area S refers to the entire continuous geographical area within which seabed target searches need to be performed; the traversal sequence Π refers to a pre-planned global access order for all sub-regions, usually represented as an ordered set of boundary points (e.g., ...). (), used to guide subordinate AUVs to efficiently and orderly move from one sub-region to the next; electronic fence It is a secure geographical boundary set within the mission area S, satisfying... This is to prevent subordinate AUVs from getting lost or entering dangerous areas.

[0023] The specific method for dividing the region into multiple sub-regions is as follows: based on communication reachability distance. As the core constraint, the entire task region S is divided into a series of sub-regions, forming a set of sub-regions. For any sub-region obtained after segmentation, the shortest underwater acoustic path length between any point x within it and the main control platform or a designated relay node. All must meet This ensures that all subordinate AUVs maintain a reliable communication connection with the main control platform while operating within each sub-region. The specific scale and geometry of the sub-regions are determined by... The derived upper bound is used for control. In practice, a regular grid partitioning method is preferred, or other equivalent decomposition methods that can ensure "full coverage of communication reachability" are adopted, such as polygon splicing that considers terrain and no-fly zone constraints. While completing the area partitioning, the system will determine the set of boundary points for each sub-region and generate the aforementioned global traversal sequence Π, and set the electronic fence for each sub-region. .

[0024] Step S102, according to the preset measuring line spacing Generate a set of parallel survey lines for each sub-region Based on the total number of parallel survey lines in each sub-region The number of subordinate AUVs and the assignment of survey line task sequences to each subordinate AUV based on the modulus principle.

[0025] In this step, the direction of travel is generated simultaneously with the set of parallel survey lines. direction of travel This refers to the unified forward orientation set for a set of parallel survey lines generated within a sub-region, such as a north-south or east-west direction. The selection of this direction is a crucial parameter in path planning, optimizing coverage efficiency and reducing the number of turns and ineffective navigation by subordinate AUVs. The survey line morphology can be selected according to mission requirements and sea conditions. Typical morphologies include: the highly efficient and easy-to-execute "comb" shape, the "zigzag" shape adaptable to complex boundaries, and the "loop" shape for refined searching in local areas. The length of the survey line is determined by the specific geometric scale of the sub-region it occupies. The decision is that each survey line needs to cover the width of its corresponding sub-region.

[0026] In step S103, each slave AUV executes its assigned survey line task and transmits target information to the main control platform according to a preset protocol.

[0027] In this step, the preset protocol can be a task protocol packet {AUV_ID, num, Region_ID, Region_Point, Spacing} issued by the master control platform to the subordinate AUVs. AUV_ID represents the unique identifier of the subordinate AUV, num represents the total number of subordinate AUVs participating in the current sub-region collaborative operation, Region_ID represents the identifier of the current sub-region, and Region_Point represents the set of boundary coordinate points defining the scope of the current sub-region. The transmission of target information can be time-slotted reporting or event-triggered incremental updates, and the transmission process can be encrypted. This embodiment does not limit the data structure and transmission method of the preset protocol.

[0028] Step S104: The main control platform evaluates the execution status of each sub-region based on the target information transmitted by each slave AUV; wherein the execution status includes in progress, partially completed, and completed.

[0029] In this step, after receiving the target information transmitted by each subordinate AUV, the master control platform can also perform data integrity verification on the target information. On the one hand, the master control platform evaluates the execution status of each sub-region based on this information; on the other hand, the master control platform also constructs and maintains a coverage progress map based on the received target information. Target confidence heatmap In conjunction with electronic fence boundary crossing detection, it identifies various abnormal situations in real time and records these abnormal situations in a dynamic abnormal event set. Coverage progress map A target confidence heatmap is used to clearly reflect the areas covered and uncovered by the search within the task area and its sub-regions. Used to indicate the probability of a real target existing in different geographical locations.

[0030] In step S105, when there is a first sub-region whose execution status is partially completed, an assistant is selected from all subordinate AUVs in the first sub-region that are in an idle state based on a preset cost function, and an unexecuted survey line task is assigned to the assistant and the assistant is scheduled to execute.

[0031] In this step, the scheduling strategy can be centralized, hierarchical, or intermittent distributed scheduling, and this embodiment does not impose any restrictions on it.

[0032] Step S106: If there is a second sub-region whose execution state is completed, select a third sub-region from all sub-regions whose execution state is not completed based on the nearest boundary principle. And in the third sub-region Select the optimal entry point on the boundary based on the nearest point principle. Generate the path from the end point of the second sub-region to the optimal entry point. The connection path; wherein, the connection path should be within the communication reach distance. and electronic fence Within the range.

[0033] Step S107: Schedule all subordinate AUVs in the second sub-region to move along the connecting path to the third sub-region. The third sub-region Unexecuted survey line tasks in the parallel survey line set are remapped to the third sub-region according to the modulus rules. Currently, all subordinate AUVs perform a remapping survey line task.

[0034] In this step, the scheduling strategy can be centralized, hierarchical, or intermittent distributed scheduling, and this embodiment does not impose any restrictions on it.

[0035] Step S108: When the target confidence level in the target state transmitted by the first slave AUV is greater than or equal to a preset threshold, the first slave AUV is scheduled to perform target verification or evidence collection actions. After the actions are completed, the first slave AUV continues to perform the line surveying task.

[0036] Step S109: There is a communication anomaly in the second subordinate AUV, equipment failure, or the location exceeds the electronic fence. If the energy level falls below the preset safety threshold, an emergency strategy is triggered; once the second slave AUV returns to normal, the main control platform will re-plan the task.

[0037] This embodiment divides the task area into multiple sub-regions and sets up electronic fences based on communication distance constraints. Parallel survey lines are generated within each sub-region, and survey line tasks are assigned to subordinate AUVs according to the modulus principle, achieving equal workload division. Each subordinate AUV executes its task and transmits target information to the main control platform. The main control platform evaluates the progress status of each sub-region based on the target information and dynamically schedules subordinate AUVs to work collaboratively. When the target confidence level meets the standard, a verification and evidence collection task is inserted. For anomalies such as communication interruptions, boundary crossings, or low energy, emergency strategies are implemented, and unified replanning is performed after the anomaly is resolved. This application, through a collaborative operation framework under communication constraints, achieves a balance between complete coverage, continuous operation, and accurate target search in a large sea area, improving operational efficiency and reliability.

[0038] This application embodiment provides a possible implementation method, in which the preset survey line spacing is mentioned in step S102 above. satisfy: (1) In equation (1), This refers to the effective field of view of the sensor mounted on the AUV. As a preset redundancy coefficient, and ; Total number of survey lines satisfy: (2) In equation (2), is the geometric scale of the sub-region.

[0039] This embodiment determines the spacing between measuring lines. The upper limit allows for adjustment of the scan overlap rate based on task requirements, while ensuring coverage continuity; subsequently, based on this spacing and the geometric scale of the sub-region... The total number of survey lines required to cover the entire sub-region width was determined by calculation and rounding, thus providing an accurate input of the workload for subsequent equal-load task allocation.

[0040] This application embodiment provides a possible implementation method, in which the total number of survey lines in step S102 above is based on the set of parallel survey lines in each sub-region. The number of subordinate AUVs is determined, and a survey line task sequence is assigned to each subordinate AUV according to the modulus principle, including: Get the total number of subordinate AUVs in the fourth sub-region ; Assign a sequential number to each subordinate AUV in the fourth sub-region; For the sequential number is Subordinate AUVs, survey line mission sequence satisfy: (3) In equation (3), Greater than or equal to 1 and less than or equal to .

[0041] This embodiment generates the survey line task sequence for each subordinate AUV by using the modulo principle, which ensures that the total survey line task is evenly distributed among all subordinate AUVs, achieving load balancing. At the same time, it makes the survey lines assigned to each subordinate AUV spatially staggered, which is beneficial to improving collaborative coverage efficiency and data diversity.

[0042] This application provides a possible implementation method. In step S103 above, the target information includes the subordinate AUV identifier AUV_ID, timestamp Time, sub-region identifier Region_ID, subordinate AUV status Stateflag, task progress process, position position, error information err, remaining energy Restpower, heartbeat information Heartbeat and target status Target_State. For the i-th subordinate AUV, satisfy: (4) In equation (4), Let be the total measurement line length of the i-th subordinate AUV. Let be the total length of the survey line completed by the i-th subordinate AUV.

[0043] This embodiment defines a unified data structure for the target information reported by subordinate AUVs, thereby forming a comprehensive status report. The mission progress is not directly transmitted in raw mileage, but is converted into a standardized percentage indicator through a formula. The specific mileage is abstracted into a unified progress percentage, providing a direct and comparable data basis for the main control platform to quantitatively evaluate individual contributions and the overall regional completion status.

[0044] This application provides a possible implementation method in which the main control platform obtains the time of the most recent heartbeat information reported by the third subordinate AUV. If the current time t and The difference is greater than the preset heartbeat timeout threshold. If so, the main control platform determines that the third subordinate AUV communication is abnormal.

[0045] This embodiment records the time of the most recent heartbeat report from each slave AUV and continuously compares it with the current time to determine the communication status of the slave AUV. It transforms discrete, periodic heartbeat signals into a continuous and reliable monitoring capability of communication link connectivity, providing crucial early warning for the system to trigger emergency strategies in a timely manner.

[0046] This application embodiment provides a possible implementation method, in which the master control platform evaluates the execution status of each sub-region based on the target information transmitted by each slave AUV in step S104 above, including: The main control platform calculates the completion status of all survey line tasks within the same sub-region based on the target information reported by all subordinate AUVs. If all subordinate AUVs within the same sub-region are performing surveying tasks, then the execution status of the sub-region is determined to be "in execution". If within the same sub-region there are both subordinate AUVs performing survey tasks and subordinate AUVs that have completed survey tasks and are idle, then the execution status of the sub-region is determined to be partially completed. If all subordinate AUVs within the same sub-region have completed their survey tasks and are in an idle state, then the execution status of the sub-region is determined to be completed.

[0047] This embodiment aggregates and analyzes the task progress reported by all subordinate AUVs within the same sub-region, summarizing the individual work status into the overall execution status at the regional level. This achieves quantitative determination from discrete individual statuses to a unified regional operation stage, providing a clear basis for subsequent dynamic scheduling decisions.

[0048] This application embodiment provides a possible implementation method, in which step S105 above selects an assistant from all subordinate AUVs in an idle state in the first sub-region based on a preset cost function, including: The main control platform identifies all idle subordinate AUVs within the first sub-region, forming a candidate assisting AUV set; For each slave in the candidate assist AUV set Calculate the cost of assistance : (5) In equation (5), for The distance to the unmeasured line segment for Remaining energy For the weighting factor; Main control platform selects assistance cost smallest subordinate As an facilitator.

[0049] This embodiment selects candidates from idle subordinate AUVs and comprehensively calculates their maneuvering distance to unfinished mission points and their remaining energy status. Using a quantified cost function as the decision-making basis, it transforms the two key resource states of subordinate AUVs—spatial location and endurance—into a comparable optimization index, thereby selecting the assistance unit with the lowest overall cost and achieving dynamic optimal allocation of mission resources in a partially completed state.

[0050] This application embodiment provides a possible implementation method in which, in step S106 above, a third sub-region is selected from all sub-regions whose execution state is not completed based on the nearest boundary principle. And in the third sub-region Select the optimal entry point on the boundary based on the nearest point principle. ,include: The main control platform groups all sub-regions whose execution status is not yet complete into a set of incomplete sub-regions. ; satisfy: (6) In equation (6), For system reference pose; Optimal entry point satisfy: (7) In equation (7), For the third sub-region The set of boundary points.

[0051] This embodiment transforms the problem of region selection and path connection into a sequential decision-making problem with the goal of minimizing the overall transfer distance, thereby providing a highly efficient and low-cost cross-regional operation guidance strategy for subordinate AUVs.

[0052] This application embodiment provides a possible implementation method in which the first subordinate AUV is scheduled to perform target review or evidence collection actions in step S108 above, including: The main control platform determines the target type in the target status reported by the first subordinate AUV; If the target type is a subsea pipeline, a first verification path is generated along the local tangent of the target, and the first subordinate AUV is controlled to navigate along the first verification path, while constraining the navigation depth and height above the bottom. If the target type is a point object, a second core path is generated around the target or distributed in a star shape, and the first subordinate AUV is controlled to navigate along the second core path; After the review is completed, the target dictionary D is updated; the target dictionary D includes target type, target location, target scale, and updated target confidence level.

[0053] This embodiment generates specific and executable verification navigation paths and control commands based on the type attributes of the target state, realizing a closed-loop operation from target identification to refined evidence collection and information archiving.

[0054] This application embodiment provides a possible implementation method where, in step S109 above, there are issues such as second subordinate AUV communication abnormality, equipment failure, or location exceeding the electronic fence. Or, if the energy level falls below a preset safety threshold, an emergency strategy is triggered, including: When the second slave AUV experiences a communication anomaly or equipment failure, the proximity relay strategy is triggered, and the main control platform dispatches a nearby slave AUV to relay in order to rebuild the communication connection. When the location of the second subordinate AUV is outside the electronic fence When the time comes, the return-to-base replanning strategy is triggered, controlling the second slave AUV to execute the automatic return-to-base or emergency ascent and recovery procedure. At the same time, the main control platform reallocates the survey line tasks that the second slave AUV has not completed. When the energy of the second slave AUV is lower than the preset safety threshold, a local degradation strategy is triggered, switching to a low-power or standby operating mode.

[0055] In this embodiment, the preset safety threshold is determined comprehensively based on the endurance of the slave AUV, the distance of the mission area from the base, and the ocean current conditions. For example, the preset safety threshold is set to 20% of the total battery power of the slave AUV. By mapping different types of slave AUV failures to hierarchical and differentiated emergency operations, abnormal event signals are transformed into a series of targeted and executable recovery actions and mission adjustments, so that the continuity and safety of the overall operation can be maintained to the maximum extent even when some slave AUVs fail.

[0056] The above introduces Figure 1 The embodiments shown have various implementation methods for each step. The following will further explain the multi-underwater robot seabed area cooperative search method of this application through specific embodiments.

[0057] This specific embodiment mainly addresses the shortcomings of existing seabed target search technologies, such as insufficient efficiency of single AUV operations and lack of systematic management of communication, positioning, and operation organization for multi-AUV parallel operations. It also suffers from problems such as unquantifiable progress, insufficient collaborative scheduling, and inadequate emergency fault tolerance.

[0058] like Figure 2 As shown, the process of this specific embodiment is as follows: First, for the wide-area search area, the task area is gridded with communication distance as a constraint, dividing it into sub-area sets and setting up electronic fences for each sub-area; the main AUV (i.e. the main control platform) first completes task initialization and parameter initialization, generates a set of parallel survey lines for each sub-area through survey line allocation, and then the task allocation and scheduling module, in combination with the number of subordinate AUVs, allocates survey line tasks to each subordinate AUV according to the rules and updates the task list synchronously. Subordinate AUVs perform surveying and auxiliary surveying operations according to the task list, while transmitting their own task progress, target information, position and communication status data back to the main AUV. The main AUV receives this information through the status monitoring module, performs status assessment in combination with system constraints (such as AUV speed, survey line spacing, etc.), obtains sub-task progress, platform status and target status, and then feeds the assessment results back to the decision support module. When a sub-region task is partially completed or the target confidence level is met, the decision support module drives the task allocation and scheduling module to perform survey line reassignment, sub-region planning, or emergency handling. If the subordinate AUV is in an idle state, it will be scheduled to perform tasks such as evidence collection. If an anomaly is encountered, an emergency response will be triggered. After the state is restored, the survey line task will continue to be executed, thereby realizing the collaborative search of multiple AUVs.

[0059] like Figure 3 As shown, the timing chain of this specific embodiment is as follows: 1. The master AUV (i.e., the master control platform) sends an initialization task command to the slave AUV (i.e., the subordinate AUV); 2. After receiving instructions from the AUV, begin executing the assigned task; 3. During the operation, the AUV will periodically transmit the task progress, its own platform status, and the target information detected back to the main AUV; 4. The main AUV periodically calibrates the position of the slave AUVs to ensure the accuracy of their operational positioning; 5. The main AUV completes the system evaluation based on the returned information, updates the task list of the secondary AUVs according to the evaluation results, and issues the tasks. 6. After receiving the update instruction from the AUV, update its own task list synchronously and continue to advance the operation.

[0060] The following is a detailed description of some steps in this specific embodiment: (1) Regional division stage like Figure 4 As shown, this process uses a stable communication distance threshold. To constrain the work area S Divided into multiple sub-regions that satisfy communication reachability , Figure 4 Each sub-region is 5 km× 5 km The regular grid; the traversal sequence Π of the sub-region is generated using a "comb + column-first" strategy, such as Figure 4 The direction of area traversal indicated by the middle arrow: Starting from the task's starting area (sub-area number 1), the comb traversal is completed sequentially from bottom to top, i.e., sub-areas 1→2→3→4 in column 1, sub-areas 5→6→7→8 in column 2, and then the traversal continues to the next column. This method reduces the number of reversals and empty driving distance when working across sub-areas.

[0061] (2) Generation of survey line set like Figure 5 As shown, within a single sub-region, a set of parallel survey lines is automatically generated according to the preset survey line spacing (Spacing). First, based on the effective field of view of the sensor... The redundancy coefficient is Determine that the spacing between the survey lines meets the requirements. .

[0062] In this specific embodiment, the survey line spacing is 200m; combined with the geometric scale of the sub-region... 5km, the total number of survey lines is calculated using the formula, i.e. 5000 / 200 +1 = 25 entries, corresponding to Figure 5 Parallel survey lines from L1 to L25 are established, and the direction of travel of the survey lines is determined. The survey lines are arranged longitudinally along the sub-region, ultimately forming a set of parallel survey lines covering the entire sub-region.

[0063] (3) Assignment of surveying tasks In the set of parallel survey lines in the sub-region, first determine the number of subordinate AUVs participating in the operation, and then assign a corresponding survey line index sequence to each subordinate AUV through calculation. like Figure 6 As shown, assuming there are 5 execution platforms, the measurement line index sequence corresponding to the first subordinate AUV is to select measurement lines with a 5-line interval, starting from the first measurement line. Figure 6 In this way, each slave AUV will obtain a non-overlapping survey line index sequence, thereby achieving a uniform distribution of survey line tasks among multiple slave AUVs.

[0064] (4) Execution of survey line tasks like Figure 7 As shown, the five subordinate AUVs proceeded with their assigned measurement tasks according to their respective sequence: As can be seen, different subordinate AUVs correspond to different survey lines within the sub-region. Each subordinate AUV travels independently along the survey lines within its own sequence and carries out detection operations synchronously, thereby achieving parallel coverage of survey line tasks within the sub-region and improving overall search efficiency. When the main control platform detects a target and its confidence level reaches a preset threshold, the system will insert a target verification or evidence collection sub-task in the current sub-region: if the target is a subsea pipeline, the subordinate AUV will generate a following path along the local tangent of the target and constrain the navigation depth and the height above the seabed; if it is a point object, a circular or star-shaped path will be generated to complete the measurement from multiple perspectives. After the review is completed, the subordinate AUV will write the target type, location, scale, confidence level and other information into the target dictionary, and update the target confidence heat map at the same time. The main control platform will adjust the job priority accordingly, and then roll back the process to the original coverage task.

[0065] (5) Task collaboration like Figure 8 As shown, within a sub-region, multiple subordinate AUVs perform their respective tasks and simultaneously send back unified format data containing information such as identification, time, task progress, and remaining energy to the main control platform. The main control platform quantifies the operational progress of each subordinate AUV based on this data and determines the communication status through heartbeat information, while simultaneously maintaining a coverage progress map, a target confidence heatmap, and abnormal event records.

[0066] The main control platform determines the sub-area operation status based on the transmitted information. If it is in a partially completed state (some subordinate AUVs have completed their tasks and entered idle mode), it calculates parameters such as the distance from the idle subordinate AUV to the uncompleted survey segment and the remaining energy, selects the idle subordinate AUV with the lowest cost, and assigns it an assistance task. Figure 8 Task redistribution in the middle; If the execution status of the sub-region is completed, such as Figure 9 As shown, the cross-region continuation process is initiated by first selecting the sub-region closest to the current system reference pose from the set of unfinished sub-regions. Figure 9 Subregion 2 is defined, and the nearest entry point in this subregion to the current position is determined, which is the search starting point of subregion 2.

[0067] Subsequently, a connection path is generated from the work endpoint of sub-area 1 to the entry point of the area, ensuring that the connection path meets the communication distance and electronic fence safety constraints throughout. After the subordinate AUV moves across sub-areas to sub-area 2 along the connection path, the survey line task of the area is reassigned according to the modeling rules. If necessary, the first survey line of each subordinate AUV is selected according to the principle of the shortest first segment to reduce the empty driving distance and start the operation quickly.

[0068] Once subregion 2 completes its task, the system will select subregion 3 using the same logic and complete the cross-region continuation, thereby achieving continuous and efficient search connections between multiple subregions.

[0069] This specific embodiment constructs a method system that can form a closed loop in communication reach, regional organization, task allocation, status monitoring, dynamic scheduling and emergency fault tolerance. It can ensure communication consistency and quantifiable progress at the sub-regional scale, and achieve equal load coordination and recoverable operation with low communication load at the whole region scale, thereby improving coverage efficiency, target recapture rate and task continuity.

[0070] It should be noted that the sequence numbers of the steps in the above embodiments do not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. In practical applications, all the above possible implementation methods can be arbitrarily combined in a combined manner to form possible embodiments of this application, which will not be described in detail here.

[0071] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that within the spirit and principles of this application, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the corresponding technical solutions to leave the protection scope of this application.

Claims

1. A method for cooperative search of seabed areas using multiple underwater robots, characterized in that, The method includes: Based on the reachable distance of communication Divide the task region S into multiple sub-regions to generate a set of sub-regions. and traversal sequence Set up electronic fences for each sub-area ; Based on the preset survey line spacing Generate a set of parallel survey lines for each sub-region Based on the total number of parallel survey lines in each sub-region The number of subordinate AUVs and the assignment of survey line task sequences to each subordinate AUV based on the modulus principle; Each subordinate AUV performs the assigned survey line task and transmits target information to the main control platform according to the preset protocol; The main control platform evaluates the execution status of each sub-region based on the target information transmitted by each slave AUV; the execution status includes in progress, partially completed, and completed. When there is a first sub-region where the execution status is partially completed, an assistant is selected from all subordinate AUVs in the first sub-region that are in an idle state based on a preset cost function, and the assistant is assigned an unexecuted survey line task and scheduled to execute the task. If a second sub-region exists with a completed execution state, a third sub-region is selected from all sub-regions with non-complete execution states based on the nearest boundary principle. And in the third sub-region Select the optimal entry point on the boundary based on the nearest point principle. Generate the path from the end point of the second sub-region to the optimal entry point. The connection path; wherein, the connection path should be within the communication reach distance. and electronic fence Within the range; All subordinate AUVs in the second sub-region are scheduled to move along the connecting path to the third sub-region. The third sub-region Unexecuted survey line tasks in the parallel survey line set are remapped to the third sub-region according to the modulus rules. Currently, all subordinate AUVs are performing a remapped survey line task. When the target confidence level in the target state transmitted by the first subordinate AUV is greater than or equal to a preset threshold, the first subordinate AUV is scheduled to perform target verification or evidence collection actions. After the actions are completed, the first subordinate AUV continues to perform the line measurement task. There are issues with the second subordinate AUV communication, equipment malfunction, and location outside the electronic fence. If the energy level falls below the preset safety threshold, an emergency strategy is triggered; once the second slave AUV returns to normal, the main control platform will re-plan the task.

2. The method according to claim 1, characterized in that, Preset survey line spacing satisfy: （1） In equation (1), This refers to the effective field of view of the sensor mounted on the AUV. As a preset redundancy coefficient, and ; Total number of survey lines satisfy: （2） In equation (2), is the geometric scale of the sub-region.

3. The method according to claim 1, characterized in that, The total number of survey lines based on the set of parallel survey lines within each sub-region. The number of subordinate AUVs is determined, and a survey line task sequence is assigned to each subordinate AUV according to the modulus principle, including: Get the total number of subordinate AUVs in the fourth sub-region ; Assign a sequential number to each subordinate AUV in the fourth sub-region; For the sequential number is Subordinate AUVs, survey line mission sequence satisfy: （3） In equation (3), Greater than or equal to 1 and less than or equal to .

4. The method according to claim 1, characterized in that, The target information includes the subordinate AUV identifier (AUV_ID), timestamp (Time), sub-region identifier (Region_ID), subordinate AUV status (Stateflag), task progress (process), position (position), error message (err), remaining energy (Restpower), heartbeat message (Heartbeat), and target status (Target_State). For the i-th subordinate AUV, satisfy: （4） In equation (4), Let be the total survey line length of the i-th subordinate AUV. Let be the total length of the survey line completed by the i-th subordinate AUV.

5. The method according to claim 4, characterized in that, The method further includes: The master control platform obtains the time of the most recent heartbeat information reported by the third subordinate AUV. If the current time t and The difference is greater than the preset heartbeat timeout threshold. If so, the main control platform determines that the third subordinate AUV communication is abnormal.

6. The method according to claim 1, characterized in that, The master control platform evaluates the execution status of each sub-region based on the target information transmitted by each slave AUV, including: The main control platform calculates the completion status of all survey line tasks within the same sub-region based on the target information reported by all subordinate AUVs. If all subordinate AUVs within the same sub-region are performing surveying tasks, then the execution status of the sub-region is determined to be "in execution". If within the same sub-region there are both subordinate AUVs performing survey tasks and subordinate AUVs that have completed survey tasks and are idle, then the execution status of the sub-region is determined to be partially completed. If all subordinate AUVs within the same sub-region have completed their survey tasks and are in an idle state, then the execution status of the sub-region is determined to be completed.

7. The method according to claim 6, characterized in that, Based on a preset cost function, helpers are selected from all idle subordinate AUVs in the first sub-region, including: The main control platform identifies all idle subordinate AUVs within the first sub-region, forming a candidate assisting AUV set; For each slave in the candidate assist AUV set Calculate the cost of assistance : （5） In equation (5), for The distance to the unmeasured line segment. for Remaining energy For the weighting factor; Main control platform selects assistance cost smallest subordinate As an facilitator.

8. The method according to claim 6 or 7, characterized in that, Based on the nearest boundary principle, the third sub-region is selected from all sub-regions whose execution state is not incomplete. And in the third sub-region Select the optimal entry point on the boundary based on the nearest point principle. ,include: The main control platform groups all sub-regions whose execution status is not yet complete into a set of incomplete sub-regions. ; satisfy: （6） In equation (6), For system reference pose; Optimal entry point satisfy: （7） In equation (7), For the third sub-region The set of boundary points.

9. The method according to claim 1, characterized in that, The primary subordinate AUV is dispatched to perform target verification or evidence collection actions, including: The main control platform determines the target type in the target status reported by the first subordinate AUV; If the target type is a subsea pipeline, a first verification path is generated along the local tangent of the target, and the first subordinate AUV is controlled to navigate along the first verification path, while constraining the navigation depth and height above the bottom. If the target type is a point object, a second core path is generated around the target or distributed in a star shape, and the first subordinate AUV is controlled to navigate along the second core path; After the review is completed, the target dictionary D is updated; the target dictionary D includes target type, target location, target scale, and updated target confidence level.

10. The method according to claim 5, characterized in that, There are issues with the second subordinate AUV communication, equipment malfunction, and location outside the electronic fence. Or, if the energy level falls below a preset safety threshold, an emergency strategy is triggered, including: When the second slave AUV experiences a communication anomaly or equipment failure, the proximity relay strategy is triggered, and the main control platform dispatches a nearby slave AUV to relay in order to rebuild the communication connection. When the location of the second subordinate AUV is outside the electronic fence When the time comes, the return-to-base replanning strategy is triggered, controlling the second slave AUV to execute the automatic return-to-base or emergency ascent and recovery procedure. At the same time, the main control platform reallocates the survey line tasks that the second slave AUV has not completed. When the energy of the second slave AUV is lower than the preset safety threshold, a local degradation strategy is triggered, switching to a low-power or standby operating mode.

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