Ship berthing hierarchical and cascaded double closed-loop control method and system based on tugboat cooperation

Abstract

The application discloses a ship berthing hierarchical and cascaded double closed-loop control method and system based on tugboat cooperation, and relates to the technical field of ship motion control and multi-agent cooperation. The method comprises the following steps: constructing a hierarchical and cascaded control framework based on the kinematics and dynamics models of a large ship and a tugboat system, wherein a general control layer is used for general berthing position control, and a distributed control layer is used for distributed thrust control; and using a double closed-loop control strategy to cooperatively control the tugboat system according to the hierarchical and cascaded control framework, wherein an outer ring performs task decision and cooperative planning control by comprehensively considering a berthing task sheet, port regulations, an environmental state and a ship condition, and an inner ring accepts the task decision and performs distributed cooperative control and localized execution. The application can decompose a complex berthing cooperative task into multiple levels, the different levels have clear division of labor, and the levels cooperatively work together, thereby improving the safety, smoothness and efficiency of the multi-tugboat cooperative berthing process.

Description

Technical Field

[0001] This invention relates to the field of ship motion control and multi-agent cooperation technology, and in particular to a hierarchical double closed-loop control method and system for ship berthing based on tugboat cooperation. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Tugboat assistance in berthing large vessels is a crucial aspect of port operations, and its safety and efficiency directly impact port operational effectiveness. Traditional tugboat-assisted berthing operations heavily rely on the operational experience of the captain and tugboat operator, as well as VHF radio coordination. This results in low automation, and the process is significantly affected by human skill, communication efficiency, and real-time judgment. In complex port environments and adverse weather conditions, issues such as coordination delays, inconsistent operations, and high safety risks arise.

[0004] With the development of intelligent shipping technology, some research has begun to explore the introduction of automated control methods to improve the reliability and efficiency of berthing operations. Existing research is mostly limited to single control architectures, such as centralized and distributed systems. Centralized control methods typically use a central control unit to uniformly handle global path planning, tugboat thrust distribution, and motion command generation. While this method can theoretically achieve a globally optimal solution, it faces significant challenges in practical applications: firstly, the complexity of the centralized optimization problem increases dramatically with the number of tugboats and constraints, leading to heavy computational burden, poor real-time performance, and difficulty in meeting the rapid response requirements of dynamic berthing processes; secondly, the system is highly dependent on the reliability of the central computing unit and communication links. Once a local communication interruption, a single tugboat's abnormal status, or a sudden environmental disturbance occurs, global replanning is often required, resulting in insufficient system robustness and adaptability. Fully distributed control methods, on the other hand, grant each tugboat greater autonomous decision-making power, achieving coordination through local perception and communication. While such methods possess good local adaptability and fault tolerance, they lack an effective global coordination mechanism, making it difficult to guarantee the overall consistency of the behavior of multiple tugboats and the global optimality of the berthing task. In closely collaborative berthing scenarios, they are prone to conflicts or suboptimal solutions.

[0005] Furthermore, existing research often employs relatively simple control hierarchies, typically using a two-layer planning-execution structure, lacking a complete collaborative link from global coordination to distributed execution. This structure results in a short feedback information transmission chain, coarse adjustment granularity, and limited control precision when the system responds to environmental disturbances, changes in ship status, or tugboat anomalies, making it unable to achieve high-precision collaborative response and adaptive adjustment.

[0006] In summary, existing methods suffer from the contradiction of "centralization leads to rigidity, while distribution leads to disorder" in their control architecture. They lack a collaborative control architecture that can reasonably decompose tasks, distribute computational load, and have the ability to respond quickly to anomalies and reconfigure while ensuring the optimal global task objectives. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a hierarchical dual closed-loop control method and system for ship berthing based on tugboat cooperation. This method can decompose complex berthing cooperation tasks into multiple levels, with clear division of labor among different levels and coordinated cooperation between levels, thereby improving the safety, smoothness, and efficiency of the multi-tugboat cooperative berthing process.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0009] The first aspect of this invention provides a hierarchical dual-closed-loop control method for ship berthing based on tugboat cooperation, comprising the following steps:

[0010] Obtain the motion state of the large ship and tugboat system, and establish the kinematic and dynamic model of the large ship and tugboat system;

[0011] A hierarchical control architecture is constructed based on the kinematic and dynamic model of the large ship and tugboat system. The hierarchical control architecture includes an outer ring overall control layer and an inner ring distributed control layer. The overall control layer is used for overall berthing position control, and the distributed control layer is used for distributed thrust control.

[0012] The tugboat system is controlled collaboratively using a dual-loop control strategy based on a hierarchical control architecture. The outer loop makes task decisions and coordinates planning control by integrating the berthing task description, port regulations, environmental conditions and ship conditions. The inner loop receives task decisions and performs distributed collaborative control and localized execution. The outer and inner loops are coupled through thrust commands and status feedback.

[0013] Furthermore, the specific steps for obtaining the motion states of the large ship and tugboat system and establishing the kinematic and dynamic model of the large ship and tugboat system are as follows:

[0014] Establish a kinematic and dynamic model of the large ship and tugboat system;

[0015] The motion states of multiple tugboats in the tugboat system are obtained based on the ship's coordinate system. The dynamic equations of the tugboat system are established. Based on the kinematic equations and dynamic model of the large ship, the environmental disturbances and energy consumption during the berthing process of the large ship are considered to establish a coupled model of the large ship and tugboat.

[0016] Furthermore, the specific steps for establishing the kinematic and dynamic model of the large ship and tugboat system are as follows:

[0017] The motion state of the large ship in three degrees of freedom in the horizontal plane is obtained. The velocity vector in the ship coordinate system and the position vector in the geodetic coordinate system are defined. The kinematic equations and dynamic equations of the large ship are constructed. At the same time, the dynamic models of each tugboat are established to provide a model basis for the hierarchical cooperative control of the large ship and tugboats.

[0018] Furthermore, the outer ring is the overall control layer, consisting of a task decision module and a collaborative planning module, used for the planning and coordination of global berthing tasks. The inner ring is the distributed control layer, consisting of a dynamic allocation module and a local execution module, used to receive instructions from the upper layer and realize distributed collaboration and localized execution.

[0019] Furthermore, the task decision module receives the upper-level task description, integrates the berthing task book, port regulations, environmental conditions and ship conditions, determines the global objectives and macro constraints, and generates the top-level berthing task description.

[0020] Furthermore, the collaborative planning module calculates the overall control requirements and allocates thrust based on the task description, real-time perceived ship status, tugboat status, and environmental information, generating target thrust commands for each tugboat.

[0021] Furthermore, the dynamic allocation module plans the optimal action pose and generates a local control strategy based on the target thrust command and the local state of each tugboat.

[0022] Furthermore, the local execution module executes specific control commands to drive the tugboat's movement and feeds back the status information to the upper layer, forming a closed-loop control.

[0023] Furthermore, when the system detects environmental disturbances, temporary obstacles, abnormal tugboat status, or deviations in ship motion, an error signal will be generated between the actual motion state and the desired reference trajectory. The error signal is fed back to the corresponding level of the outer loop through the inner loop, driving the controller to continuously adjust the control action until the error converges to the allowable range.

[0024] A second aspect of the present invention provides a hierarchical dual-closed-loop control system for ship berthing based on tugboat cooperation, comprising:

[0025] The data acquisition module is used to acquire the motion state of the large ship and tugboat system and to establish the kinematic and dynamic models of the large ship and tugboat system.

[0026] The control architecture construction module is used to build a hierarchical control architecture based on the kinematic and dynamic model of the large ship and tugboat system. The hierarchical control architecture includes an outer ring overall control layer and an inner ring distributed control layer. The overall control layer is used for overall berthing position control, and the distributed control layer is used for distributed thrust control.

[0027] The double-closed-loop control module is used to perform collaborative control on the tugboat system according to the hierarchical control architecture by using the double-closed-loop control strategy. Among them, the outer loop makes task decisions and collaborative planning control by integrating the berthing task book, port regulations, environmental conditions and ship conditions. The inner loop receives the task decisions and performs distributed collaborative control and local execution. The outer loop and the inner loop are coupled through thrust commands and state feedback.

[0028] The above one or more technical solutions have the following beneficial effects:

[0029] The present invention discloses a hierarchical double-closed-loop control method and system for ship berthing based on tugboat collaboration. Logically, the method constructs a double-closed-loop control architecture, where the outer loop is the overall berthing position control and the inner loop is the distributed thrust control. The two levels of the overall control layer and the distributed control layer together constitute four collaborative modules: the task decision module, the collaborative planning module, the dynamic allocation module and the local execution module. Through the working mechanism of the double-layer and four-module linkage, this architecture realizes the refined collaborative control of each tugboat on the premise of ensuring the overall coordination of global tasks.

[0030] The hierarchical double-closed-loop control method of the present invention decomposes complex berthing tasks into multiple controllable stages through a phased and multi-level collaborative control mechanism, and realizes the efficient collaboration of the four-layer architecture within each stage, significantly improving the automation level, operation safety, control accuracy and overall efficiency of large ship berthing operations. This method is especially suitable for multi-tugboat collaborative operations in complex port environments and has important engineering application value.

[0031] Through the multi-stage hierarchical double-closed-loop control process, the present invention realizes the high-precision collaboration and intelligent response of the multi-tugboat system in a dynamically uncertain environment, significantly improving the automation level, operation safety and overall efficiency of large ship berthing operations.

[0032] The advantages of the additional aspects of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 It is the overall flowchart of the hierarchical double-closed-loop control method for ship berthing based on tugboat collaboration in Embodiment Ⅰ of the present invention;

[0035] Figure 2 This is a schematic diagram of the outer loop feedback control structure in Embodiment 1 of the present invention;

[0036] Figure 3 This is a schematic diagram of the inner loop feedback control structure in Embodiment 1 of the present invention;

[0037] Figure 4 This is a schematic diagram of the dual closed-loop feedback control structure in Embodiment 1 of the present invention;

[0038] Figure 5 This is a schematic diagram of the multi-stage control of the berthing process in Embodiment 1 of the present invention. Detailed Implementation

[0039] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0040] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0041] 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, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0042] Example 1:

[0043] Embodiment 1 of the present invention provides a hierarchical dual closed-loop control method for ship berthing based on tugboat cooperation, such as... Figure 1 As shown, this embodiment adopts a clear hierarchical dual closed-loop structure, dividing the control flow into two major circular feedback control structures: the overall control layer and the distributed control layer. Each layer is further refined into core modules with specific functions, and closed-loop collaborative control is achieved through bidirectional information flow between layers.

[0044] Specifically, the following steps are included:

[0045] S1: Obtain the motion state of the large ship and tugboat system, and establish the kinematic and dynamic model of the large ship and tugboat system.

[0046] In one specific implementation, a kinematic and dynamic model of the large ship and tugboat system is first established. In this embodiment, the motion state of the large ship in three degrees of freedom in the horizontal plane is obtained, the velocity vector in the ship coordinate system and the position vector in the geodetic coordinate system are defined, and the kinematic equations and dynamic equations of the large ship are constructed. At the same time, the dynamic models of each tugboat are established, providing a model basis for the hierarchical cooperative control of the large ship and tugboats.

[0047] Specifically, in the geodetic coordinate system, the position and attitude of the large ship are represented as follows: ,in The coordinates of the ship's center of gravity Let be the bow angle, and the velocity vector in the hull coordinate system be... , These represent longitudinal velocity, lateral velocity, and turning angular velocity, respectively.

[0048] The kinematic equations of a large ship can be described as follows:

[0049] (1).

[0050] in, This represents the rate of change vector of the ship's position and attitude in the geodetic coordinate system. The rotation matrix from the ship's coordinate system to the geodetic coordinate system:

[0051] (2).

[0052] The dynamic model of the large ship is as follows:

[0053] (3).

[0054] in This represents the acceleration vector of the large ship in the ship's coordinate system. The inertia matrix includes the added mass. The Coriolis centripetal force matrix, For hydrodynamic damping matrix, The total control forces and torques acting on the large ship, of which This represents the longitudinal control force, which is provided by the resultant force of the longitudinal components of the tugboat thrust along the longitudinal axis of the hull. This represents the lateral control force, which is provided by the resultant force of the lateral component of the tugboat thrust along the hull's transverse axis. This represents the bow control torque, which is provided by the torque synthesis of the tugboat thrust relative to the ship's center of gravity, about the vertical axis of the hull. Based on the ship's coordinate system, the motion states of multiple tugboats in the tugboat system are obtained, and the dynamic equations of the tugboat system are established. Furthermore, based on the kinematic equations and dynamic model of the large ship, a coupled model of the large ship and tugboats is established, considering environmental disturbances and energy consumption during the large ship's berthing process.

[0055] Specifically, for the first i The motion of a tugboat can be described similarly as follows: and And the dynamic equation is:

[0056] (4).

[0057] In the formula This refers to the thrust and torque output by the tugboat propulsion system.

[0058] During the berthing of large ships, tugboats typically use a pushing mechanism to apply thrust to the hull, transferring the thrust to the ship through contact points. To ensure control redundancy and flexibility, four tugboats are generally symmetrically arranged on both sides of the bow and stern, forming a super-drive system. The tugboats are equipped with azimuth thrusters, possess dynamic positioning capabilities, can generate thrust in any direction, and respond to upper control commands in real time.

[0059] Therefore, we assume that the contact point between the tugboat and the large ship is fixed in the ship's coordinate system, and its position is determined by polar coordinates. Indicates tugboat thrust. With direction angle Acting on a large ship, and considering environmental disturbances (wind, waves, currents, etc.) during the ship's berthing process, what are the resultant forces and resultant moments generated by these forces in the ship's coordinate system? This can be expressed as:

[0060] (5).

[0061] in It is an environmental disturbance force estimation term, which can be obtained from the observer. This is the thrust mapping matrix. n This represents the total number of tugboats.

[0062] (6).

[0063] Furthermore, considering the energy consumption model, the energy consumption of the tugboat propeller should be kept at a low level:

[0064] (7).

[0065] in, Indicates energy consumption. It is the power consumption function of the i-th tugboat propeller, and its form is: ,in This represents the thrust direction angle of the i-th tugboat at the previous moment. For the efficiency of the tugboat propulsion system.

[0066] S2: Based on the kinematic and dynamic model of the large ship and tugboat system, a hierarchical control architecture is constructed. The hierarchical control architecture includes an outer ring overall control layer and an inner ring distributed control layer. The overall control layer is used for overall berthing position control, and the distributed control layer is used for distributed thrust control.

[0067] In one specific implementation, the outer loop feedback control structure is as follows: Figure 2 As shown. The outer ring is the overall control layer, which consists of a task decision module and a collaborative planning module, used for the planning and coordination of the global berthing task.

[0068] Specifically, the task decision module, as the system's top-level decision-making unit, receives the task description from the upper level, integrates the berthing task statement, port regulations, environmental conditions, and vessel conditions, determines the overall objectives and macro-constraints, and outputs phased berthing task instructions. The macro-constraints for this berthing include the target berthing point. Expected final course Safe berthing time window Overall risk tolerance And so on, and generate the top-level berthing task description. As a global objective, it is distributed to the collaborative planning module.

[0069] The collaborative planning module receives the global objective from the task decision module. Based on the ship's real-time attitude and speed status Environmental disturbance force estimation term It calculates the total thrust and torque required to achieve berthing, performs multi-tug thrust distribution optimization, outputs the target thrust command for each tug, and activates the corresponding feedback mechanism when an error signal is detected.

[0070] The thrust distribution problem can be expressed by the following optimization model:

[0071] (8).

[0072] in, This represents the total cost function of the thrust allocation problem, which is used to quantify the merits of the current thrust allocation scheme.

[0073] In formula (8), the optimization objectives are divided into four items: minimizing the thrust magnitude, constraining the smoothness of the thrust direction change, tracking accuracy of the total thrust, and energy consumption optimization. The above design can ensure that the system can minimize energy consumption and maintain smoothness while tracking control commands.

[0074] Satisfy constraints:

[0075] (9).

[0076] in, , and These are the weighting coefficients. The command control force or torque is calculated based on the motion error of the large ship. Indicates the first i The minimum thrust of a tugboat. Indicates the first i The maximum thrust of a tugboat, Indicates the first i The minimum thrust direction angle of a tugboat. Indicates the first i The maximum thrust direction angle of the tugboat, This indicates the maximum permissible change in the direction of thrust. Indicates the first i The thrust value of the tugboat at the previous moment The initial angle indicating the direction of the dangerous thrust. This is to ensure that the direction of thrust avoids restricted areas (such as where there are obstacles).

[0077] In formula (9), this embodiment first considers the constraint of thrust amplitude, because the thrust of each tugboat is physically limited and cannot exceed the maximum output capacity; secondly, it considers the constraint of thrust change rate, because the tugboat propeller has a corresponding dynamic delay and the corresponding change rate has a mechanical inertia limit; thirdly, it considers the thrust synthesis equation to ensure that the thrust synthesis value of the tugboat (plus environmental disturbance compensation) is exactly equal to the total thrust and total torque required for berthing; finally, it considers the constraint of dangerous orientation avoidance, because some thrust directions may cause the tugboat to collide with large ships or surrounding obstacles, or cause the tugboat to be in an unstable pushing state. Therefore, these directions need to be set as no-go zones to ensure operational safety.

[0078] In one specific implementation, the inner-loop feedback control structure is as follows: Figure 3 As shown, the inner ring is a distributed control layer, consisting of a dynamic allocation module and a local execution module, used to receive instructions from the upper layer and realize distributed collaboration and localized execution.

[0079] Specifically, the dynamic allocation module uses the target thrust commands issued by the collaborative planning module to each tugboat. For input, where Indicates the first i The target thrust of the tugboat is specified. Indicates the first i The target thrust direction angle command for the tugboat.

[0080] In this process, the dynamic allocation module takes the target thrust commands for each tugboat issued by the collaborative planning module as its core input, integrates multi-source information, and achieves collaborative planning of tugboat attitude through weighted optimization of multiple targets. Specifically, this module incorporates the following five types of factors into the optimization framework:

[0081] Thrust command mapping: Mapped to the theoretical optimal action position ,Will Mapped to the theoretically optimal heading angle As a baseline target for attitude tracking; relative position feedback: based on the current position of the tugboat. Deviation from desired position Position tracking costs are incurred to drive the tugboats to move towards the target position; inter-tugboat cooperative constraints: an inter-tugboat collision avoidance cost term is introduced. To ensure multiple tugboats maintain a safe distance within a limited working space and achieve group collaboration; environmental obstacle avoidance constraints: introducing a collision avoidance cost term between tugboats and obstacles. By combining real-time perceived local environmental information, it actively avoids fixed or temporary obstacles in the port area; attitude tracking constraints: a bow angle deviation cost term is introduced. This ensures that the tugboat maintains the correct thrust direction while reaching the target position. The above five factors are weighted and summed into the optimization objective function, with weight coefficients... The system dynamically adjusts based on berthing stage and environmental conditions to achieve a dynamic balance between tracking accuracy, collaborative safety, environmental adaptability, and attitude control. The optimization process comprehensively considers the interactions and coupling relationships among various factors. By solving this multi-objective optimization problem, the optimal operating position for each tugboat is generated. with posture This ensures precise execution of upper-level thrust commands while balancing inter-tugboat safety and environmental adaptability. In summary, the specific control objectives are as follows:

[0082] (10).

[0083] And satisfy kinematic constraints:

[0084] (11).

[0085] in, , The collision avoidance weighting coefficients respectively guarantee collision avoidance between tugboats and collision avoidance between tugboats and environmental obstacles. This is the heading tracking weight coefficient; the larger the weight, the higher the heading control accuracy requirement. Indicates the first i The desired velocity vector of a tugboat in the geodetic coordinate system It is a rotation matrix. Indicates the first i The expected heading angle of a tugboat, Indicates the first i The longitudinal speed of the tugboat, Indicates the first i The longitudinal acceleration of the tugboat, Indicates the first i Environmental disturbance term for the tugboat Indicates the first i The thrust control input of the tugboat Indicates the first i The water resistance function of a tugboat. Indicates the first i The mass of the tugboat Indicates the maximum permissible speed of the tugboat. Indicates the first i The maximum permissible acceleration of a tugboat, Indicates the first i The bow angular velocity of the tugboat, Indicates the first i The angular velocity of the tugboat rotating about its vertical axis. Indicates the first i The bow angle acceleration of the tugboat, Indicates the first i The moment of inertia of a tugboat Indicates the first i The maximum permissible bow turning angular velocity of a tugboat; obstalcezones indicate the area of ​​obstacles.

[0086] Specifically, the local execution module is deployed on each tugboat body, and will dynamically allocate the target position output by the module. with posture Converted to a specific rudder angle via the local controller. Rotation speed The actuator commands drive the tugboat to complete precise actions and feed back real-time status information to the upper level.

[0087] The control law takes the following form:

[0088] (12).

[0089] in, , , These represent the bow angle proportional control gain, bow angle differential control gain, and thrust feedback compensation gain, respectively. For thrust coefficient, This is the measured thrust.

[0090] S3: The tugboat system is controlled collaboratively using a dual-closed-loop control strategy based on a hierarchical control architecture.

[0091] In one specific implementation, the outer ring makes task decisions and coordinates planning and control by comprehensively considering the berthing task statement, port regulations, environmental conditions and ship conditions. The inner ring receives the task decisions and performs distributed collaborative control and localized execution. The outer ring and the inner ring are coupled through thrust commands and status feedback.

[0092] The feedback control structure after combining two closed loops is as follows: Figure 4 As shown, in the dual closed-loop control structure, each level is connected through information flow, forming a closed-loop control link from task decision-making to local execution, and then from execution status feedback to planning adjustments. The overall control layer and the distributed control layer achieve coordination and coupling, unifying global objectives with local execution. This ensures that the system can dynamically adapt to environmental changes and respond to abnormal events during multi-stage berthing processes, ultimately achieving the goal of safe, smooth, and efficient berthing operations.

[0093] Specifically, the following steps are included:

[0094] S3.1: First, the system is initialized, and module connections between the double closed-loop multi-level system are established.

[0095] The task decision module receives the upper-level task description, integrates the berthing task statement, port regulations, environmental conditions, and vessel conditions, determines the overall objectives and macro-constraints, and generates the top-level berthing task description. .

[0096] S3.2: Secondly, the collaborative planning module is based on the task description. Real-time sensing of ship status ( ), tugboat status and environmental information Calculate the overall control requirements and allocate thrust, generating target thrust commands for each tugboat. .

[0097] S3.3: Next, the dynamic allocation module plans the optimal action pose and generates a local control strategy based on the target thrust command and the local state of each tugboat.

[0098] S3.4: Finally, the local execution module executes specific control commands to drive the tugboat to move and feeds back the status information to the upper layer, forming a closed-loop control.

[0099] When the system detects environmental disturbances, temporary obstacles, abnormal tugboat status, or deviations in ship motion, an error signal will be generated between the actual motion state and the desired reference trajectory. This error signal is fed back to the corresponding level in the outer loop via the inner loop, driving the controller to continuously adjust its control actions until the error converges to an acceptable range. Specifically, the local execution layer feeds back real-time thrust and attitude deviations to the dynamic allocation module, dynamically adjusting local control commands to reduce instantaneous errors. If the error persists or exceeds the local adjustment capability, the dynamic allocation module will re-optimize the thrust allocation scheme and correct the multi-tugboat cooperative control action. When the error amplitude or duration exceeds a preset threshold, the cooperative planning module adjusts the desired trajectory or control objective, guiding the system to converge back to a new reference trajectory.

[0100] From a macroscopic perspective, the macroscopic representation of the dual closed-loop control process in this invention is as follows:

[0101] Assume the overall transfer function of the two-layer six-module controller is The transfer function of the coupled model of the large ship and tugboat is: The transfer function of the outer loop feedback loop is For the corresponding state monitoring and trajectory deviation feedback, the closed-loop transfer function of the outer loop feedback controller is... The format is as follows:

[0102] (13).

[0103] Assume the overall transfer function of the controller in the distributed control layer is The transfer function of the tugboat dynamics model is The transfer function of the inner loop feedback loop is For the corresponding state monitoring and trajectory deviation feedback, the closed-loop transfer function of the inner-loop feedback controller is... The format is as follows:

[0104] (14).

[0105] The outer and inner loops are coupled through thrust command and state feedback, and the overall system transfer function... for

[0106] (15).

[0107] in, This is the inner and outer loop coupling transfer function, which describes the thrust distribution and state interaction.

[0108] like Figure 5 As shown, this embodiment uses the example of three tugboats working together to assist a large bulk carrier in berthing in a port area with fixed wharves and floating obstacles to illustrate the specific implementation process of the present invention.

[0109] Specifically, the berthing process is divided into several stages carried out sequentially:

[0110] Phase 1: From starting point A to control point B. After system startup, the task decision module of the overall control layer determines the coordinates of the target berthing point based on berth assignment information, weather forecast data, etc. The expected final bow direction Maximum permitted berthing time The system defines the safe zone and generates a global mission description file. When the ship is at starting point A, the system initiates the first control process. The mission decision module generates the stage control objective from point A to point B, and the collaborative planning module calculates the required total system thrust based on this objective. With torque The target thrust command is then distributed to tugboats 1, 2, and 3 using a collaborative optimization algorithm, generating the target thrust command for each tugboat. , , After the task is issued to the distributed control layer, the dynamic allocation module, based on the target thrust command and considering the relative positions of each tugboat and the ship, as well as the local environment, autonomously adjusts each tugboat to its optimal point of action and attitude. The local execution module then executes the specific control commands, driving the tugboats to work collaboratively and smoothly tow the ship to control point B.

[0111] Phase Two: From Control Point B to Control Point C. After the vessel reaches point B, the system initiates the second control process. The overall control module's task decision module updates the control objective and generates phased control instructions from point B to point C. The collaborative planning module recalculates the thrust requirement and optimizes the allocation scheme. The dynamic allocation module adjusts the tugboat's position and thrust direction based on environmental changes (such as wind and current effects). The local execution module executes the updated control instructions. Through multi-level collaborative control, the vessel is precisely guided to control point C.

[0112] Phase Three: From Control Point C to Final Berthing Point D. After the vessel arrives at point C, the system initiates the third control process. The task decision module generates the control objective for the final berthing phase, the collaborative planning module performs refined thrust allocation, the dynamic allocation module optimizes the final position and attitude of each tugboat, and the local execution module executes high-precision control commands, ultimately guiding the vessel safely and smoothly to berth at the target point D.

[0113] Throughout the berthing process, the system continuously monitors the ship's motion and environmental changes. If a sudden crosswind disturbance or temporary obstacle is detected, the system responds rapidly through its inner loop: the collaborative planning module adjusts the tugboat's attitude in real time, the dynamic allocation module optimizes the thrust distribution scheme, and the task decision module monitors the overall status and updates the control strategy. Through multi-stage, multi-level collaborative control, the system achieves high-precision coordination and intelligent response of multi-tugboat systems in dynamic and uncertain environments.

[0114] Example 2:

[0115] Embodiment 2 of the present invention provides a hierarchical dual closed-loop control system for ship berthing based on tugboat cooperation, comprising:

[0116] The data acquisition module is used to acquire the motion state of the large ship and tugboat system and to establish the kinematic and dynamic models of the large ship and tugboat system.

[0117] The control architecture construction module is used to build a hierarchical control architecture based on the kinematic and dynamic model of the large ship and tugboat system. The hierarchical control architecture includes an outer ring overall control layer and an inner ring distributed control layer. The overall control layer is used for overall berthing position control, and the distributed control layer is used for distributed thrust control.

[0118] The dual-loop control module is used to coordinate the control of the tugboat system according to a hierarchical control architecture using a dual-loop control strategy. The outer loop makes task decisions and coordinates the control by integrating the berthing task book, port regulations, environmental conditions and ship conditions. The inner loop receives the task decisions and performs distributed coordinated control and localized execution. The outer loop and the inner loop are coupled through thrust commands and status feedback.

[0119] The steps and methods involved in the above embodiment two correspond to those in embodiment one. For specific implementation details, please refer to the relevant description section of embodiment one.

[0120] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0121] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in or transmitted through a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data processing device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, an optical medium, or a semiconductor medium, etc.

[0122] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A hierarchical dual-closed-loop control method for ship berthing based on tugboat cooperation, characterized in that, Includes the following steps: Obtain the motion state of the large ship and tugboat system, and establish the kinematic and dynamic model of the large ship and tugboat system; A hierarchical control architecture is constructed based on the kinematic and dynamic model of the large ship and tugboat system. The hierarchical control architecture includes an outer ring overall control layer and an inner ring distributed control layer. The overall control layer is used for overall berthing position control, and the distributed control layer is used for distributed thrust control. The outer ring is the overall control layer, consisting of a task decision module and a collaborative planning module, used for the planning and coordination of the global berthing task. The inner ring is the distributed control layer, consisting of a dynamic allocation module and a local execution module, used to receive instructions from the upper layer and realize distributed collaboration and localized execution. The task decision module receives the upper layer task description, integrates the berthing task book, port regulations, environmental conditions, and ship conditions to determine the global objectives and macro constraints, and generates the top-level berthing task description. The collaborative planning module calculates the overall control requirements and allocates thrust based on the task description, real-time perceived ship status, tugboat status, and environmental information, generating target thrust commands for each tugboat. The dynamic allocation module plans the optimal action pose and generates a local control strategy based on the target thrust commands and the local states of each tugboat. The local execution module executes specific control commands, drives the tugboat movement, and feeds back the status information to the upper layer, forming a closed-loop control. The thrust distribution problem can be formulated using the following optimization model: ， in, The total cost function representing the thrust allocation problem has four optimization objectives: minimizing the thrust magnitude, ensuring the smoothness of thrust direction changes, achieving high tracking accuracy of total thrust, and optimizing energy consumption. Satisfy constraints: ， in, , and These are the weighting coefficients. The command control force or torque is calculated based on the motion error of the large ship. Indicates the first i The minimum thrust of a tugboat. Indicates the first i The maximum thrust of a tugboat, Indicates the first i The minimum thrust direction angle of a tugboat. Indicates the first i The maximum thrust direction angle of the tugboat, This indicates the maximum permissible change in the direction of thrust. Indicates the first i The thrust value of the tugboat at the previous moment The initial angle indicating the direction of the dangerous thrust. This is to ensure that the direction of the thrust avoids the restricted area; The tugboat system is controlled collaboratively using a dual-loop control strategy based on a hierarchical control architecture. The outer loop makes task decisions and coordinates planning control by integrating the berthing task description, port regulations, environmental conditions and ship conditions. The inner loop receives task decisions and performs distributed collaborative control and localized execution. The outer and inner loops are coupled through thrust commands and status feedback.

2. The hierarchical dual-closed-loop control method for ship berthing based on tugboat cooperation as described in claim 1, characterized in that, The specific steps for obtaining the motion state of the large ship and tugboat system and establishing the kinematic and dynamic model of the large ship and tugboat system are as follows: Establish a kinematic and dynamic model of the large ship and tugboat system; The motion states of multiple tugboats in the tugboat system are obtained based on the ship's coordinate system. The dynamic equations of the tugboat system are established. Based on the kinematic equations and dynamic model of the large ship, the environmental disturbances and energy consumption during the berthing process of the large ship are considered to establish a coupled model of the large ship and tugboat.

3. The hierarchical dual-closed-loop control method for ship berthing based on tugboat cooperation as described in claim 2, characterized in that, The specific steps for establishing the kinematic and dynamic model of the large ship and tugboat system are as follows: The motion state of the large ship in three degrees of freedom in the horizontal plane is obtained. The velocity vector in the ship coordinate system and the position vector in the geodetic coordinate system are defined. The kinematic equations and dynamic equations of the large ship are constructed. At the same time, the dynamic models of each tugboat are established to provide a model basis for the hierarchical cooperative control of the large ship and tugboats.

4. The hierarchical dual-closed-loop control method for ship berthing based on tugboat cooperation as described in claim 1, characterized in that, When the system detects environmental disturbances, temporary obstacles, abnormal tugboat status, or deviations in ship motion, an error signal will be generated between the actual motion state and the desired reference trajectory. The error signal is fed back to the corresponding level of the outer loop through the inner loop, driving the controller to continuously adjust the control action until the error converges to the allowable range.

5. A control system for the hierarchical dual-closed-loop control method for ship berthing based on tugboat cooperation as described in any one of claims 1-4, characterized in that, include: The data acquisition module is used to acquire the motion state of the large ship and tugboat system and to establish the kinematic and dynamic models of the large ship and tugboat system. The control architecture construction module is used to build a hierarchical control architecture based on the kinematic and dynamic model of the large ship and tugboat system. The hierarchical control architecture includes an outer ring overall control layer and an inner ring distributed control layer. The overall control layer is used for overall berthing position control, and the distributed control layer is used for distributed thrust control. The dual-loop control module is used to coordinate the control of the tugboat system according to a hierarchical control architecture using a dual-loop control strategy. The outer loop makes task decisions and coordinates the control by integrating the berthing task book, port regulations, environmental conditions and ship conditions. The inner loop receives the task decisions and performs distributed coordinated control and localized execution. The outer loop and the inner loop are coupled through thrust commands and status feedback.

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