Marine train extension structure for unmanned surface vehicle and control method

Abstract

The present application belongs to the field of machinery, control and ship technology, and discloses a sea train expansion structure and control method for unmanned ships. The structure comprises: a docking male head arranged at the bow of the unmanned ship and a docking female head arranged at the stern of the unmanned ship; the docking male head comprises an arc-shaped rod and multiple straight rods arranged along the arc-shaped rod, each straight rod extending outward along the same side of the arc-shaped rod; the docking female head comprises at least one impact type self-locking structure; when the front and rear unmanned ships are longitudinally docked head to tail, the arc-shaped rod collides with the locking tongue arranged on the front unmanned ship to make the locking tongue retract into the locking body, so that the arc-shaped rod enters the locking body along the radial direction thereof, and then the locking tongue is automatically closed under the action of gravity or elastic force; after all the unmanned ships are docked, they are moved to the target position along the arc-shaped rod under the action of tension to realize the sea train; and the expansion plate body arranged on the hull of the unmanned ship is further included. The present application can improve the flexibility of sea train expansion, avoid excessive stress concentration, and improve the single docking success rate.

Description

Technical Field

[0001] This invention belongs to the fields of mechanical, control and marine technology, and more specifically, relates to a marine train extension structure and control method for unmanned surface vessels. Background Technology

[0002] To achieve physical connections between unmanned surface vessels (USVs) or between USVs and fixed platforms (such as shore-based or offshore base stations) to perform tasks such as towing, formation, charging, data transmission, or constructing floating platforms, autonomous docking and self-locking technologies for USVs are crucial. However, continuous disturbances in the aquatic environment (such as waves and currents) pose significant challenges to the reliability, success rate, and post-connection stability of docking mechanisms. Several docking self-locking schemes exist in existing technologies, but each has its limitations.

[0003] The paper "Design of a Self-Correctable Docking Mechanism in Disturbed WaterSurface Environment" (IEEE Robotics and Automation Letters, Vol. 9, No. 11, November 2024) discloses a self-correcting docking mechanism based on the Reuleaux tetrahedron. This mechanism consists of a male and a female connector, allowing for a large initial docking angle deviation and possessing self-correcting capabilities during docking. Its docking is passive, requiring no additional sensors to detect the docking completion status, and there is no relative displacement or rotation between the male and female connectors after docking, facilitating stable charging or data transmission. However, the docking termination angle is limited to three fixed discrete values. While this provides determinism for specific scenarios, its flexibility is limited in "sea train" scenarios requiring flexible and continuous adjustment of the connection angle to cope with complex sea conditions or different mission configurations. Furthermore, once the connection is established, it is rigidly fixed, exhibiting weak adaptability to overall structural deformation and stress concentration caused by waves after multiple vessels are connected.

[0004] The "Autonomous Latching System for Robobic Boats" (2019 International Conference on Robotics and Automation) disclosed an autonomous locking system based on ball and socket joints. This system allows two docked boats to rotate and move relative to each other in swell and roll directions, thus adapting to surface disturbances and reducing stress on the structure and hull. However, because the ball and socket joint has a small acceptable docking error range, vision guidance is required for high-precision docking. However, in real-world maritime environments, under the combined influence of wind, waves, and currents, underactuated unmanned boats experience continuous attitude and position changes and maneuvering delays. Even with a vision-based approach, precise alignment and docking are often not achieved on the first attempt, requiring multiple adjustments and retrying. This iterative process is not only time-consuming but also significantly extends the overall formation connection time when building extended structures of multiple unmanned boats, such as a "sea train," reducing mission efficiency. Meanwhile, the repeated starting and stopping of the propellers and the maneuvering of the hull during multiple attempts will generate additional, irregular induced waves in the waters near the formation, interfering with the stability of nearby connected or to-be-connected hulls, further increasing the difficulty and uncertainty of subsequent docking.

[0005] In summary, existing technologies for autonomous docking on disturbed water surfaces present a trade-off between docking robustness and post-connection structural characteristics. While self-correcting mechanisms improve initial docking success rates, their discrete and fixed connection states and angles limit the flexible reconfiguration required for the "sea train" during missions and lack the ability to handle overall structural deformation and stress concentration. Docking schemes relying on high-precision vision guidance often fail to achieve success on the first attempt when faced with continuous disturbances and maneuvering delays from underactuated unmanned surface vessels in real-world sea conditions, requiring multiple attempts. This significantly reduces the efficiency of multi-vessel extended connections, and the induced waves generated by repeated maneuvers exacerbate formation instability, creating a vicious cycle. Currently, there is a lack of a dedicated connection scheme for efficiently constructing "sea train"-style scalable structures. This scheme must effectively overcome the adverse effects of continuous surface disturbances on docking accuracy, significantly improving the single-dock success rate; after connection, it should possess a certain degree of flexible reconfiguration capability, and its structure should allow the extended body to adapt to overall wave loads within a certain range, avoiding excessive stress concentration. Summary of the Invention

[0006] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a marine train extension structure and control method for unmanned surface vessels, which aims to improve the flexibility of marine train extension, avoid excessive stress concentration, and improve the success rate of single docking.

[0007] To achieve the above objectives, the present invention provides a marine train extension structure for unmanned surface vessels (USVs), comprising: a male docking head disposed at the bow of the USV and a female docking head disposed at the stern of the USV; The male connector includes an arc-shaped bar as the main body and multiple straight bars arranged along the arc-shaped bar, and the multiple straight bars all extend outward along the same side of the arc-shaped bar; the female connector includes at least one impact-type self-locking structure, the impact-type self-locking structure includes a lock body and a built-in lock tongue. During longitudinal docking of the unmanned surface vessels (USVs), the arc-shaped bar in the male docking head of the latter USV collides with the locking tongue in the female docking head of the former USV, causing the locking tongue to retract into the lock body. This allows the arc-shaped bar to enter the lock body radially. Subsequently, the locking tongue automatically closes under its own gravity or elastic force, achieving impact-type self-locking. After all USVs have docked, they move and slide along the guide of the arc-shaped bar under the action of tension to slide towards the target position, realizing a sea train. The guide sliding distance is the length of the arc segment between two adjacent straight bars on the arc-shaped bar.

[0008] Furthermore, it includes: the multiple straight bars are three straight bars, namely the two ends of the arc-shaped bar and the midpoint of the arc-shaped bar.

[0009] Furthermore, the guide profile of the arc-shaped rod is determined using a cubic spline curve based on the planar coordinates of the connection points between the three straight rods and the arc-shaped rod.

[0010] Furthermore, it also includes an extension plate body installed on the hull of the unmanned surface vessel (USV), and the ends of the multiple straight bars are provided with connectors, which are connected to the extension plate body on the USV hull. The extension plate body is also provided with a groove array adapted to the width of the lock body, and the lock bodies of each impact-type self-locking structure are respectively welded to the groove array on the USV hull.

[0011] Furthermore, the extension plate body is a cuboid shell that completely covers the hull of the unmanned surface vessel and is disposed on the top of the hull of the unmanned surface vessel.

[0012] Furthermore, the male connector and the female connector are made of stainless steel; the extension plate body is made of PE material with a strength exceeding a preset threshold.

[0013] Furthermore, the male docking head, the female docking head, and the extension plate body are all rigidly connected to the unmanned surface vessel.

[0014] Furthermore, the impact-type self-locking structure is a cage-type impact safety lock structure, and the collision surface between the arc-shaped bar and the lock tongue is an arc surface.

[0015] The present invention also provides an unmanned surface vessel docking control method based on a marine train extension structure, wherein the marine train extension structure is any one of the marine train extension structures described above, and the unmanned surface vessel docking control method includes: During the independent navigation phase, all unmanned surface vessels (USVs) are controlled to proceed in parallel to their respective initial target points; wherein the initial target points are on a straight line and the target heading angles of all USVs point to the same straight line direction. During the heading angle fine-tuning phase, when the distance between the unmanned surface vessel and the initial target point is less than a preset distance, a fine-tuning algorithm is used to detect the current heading angle deviation. Based on the current heading angle deviation, an adaptive PID controller with anti-integral saturation is used to output differential thrust to fine-tune the current heading angle so that the current heading angle tends to the target heading angle. When the unmanned surface vessel reaches a certain number of stable discriminations, it is determined that the unmanned surface vessel has reached the initial target point. During the target docking phase, the unmanned vessels are docked longitudinally end to end in sequence. After all the unmanned vessels are docked, they move and slide along the arc-shaped guide bar under the pull force to slide towards the target position, thus realizing the sea train.

[0016] Furthermore, during the independent navigation phase, based on the starting point, current path point, and initial target point of each unmanned surface vessel, A... The algorithm outputs a planned path to guide the unmanned surface vessel (USV) to the initial target point; and adjusts A based on the deviation between the current path point and the initial target point, as well as the current heading angle deviation. The algorithm outputs the planned path.

[0017] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects: (1) This invention designs a new marine train extension structure, which achieves longitudinal bow-to-stern docking of unmanned surface vessels by combining an arc-shaped rod structure with an impact-type self-locking structure. Compared with existing self-correcting mechanisms, since straight bars are set on the arc-shaped rod, the tolerance error range of the arc-shaped rod entering the lock body radially and the distance of the lock body (hull) sliding along the arc-shaped rod after docking are both the length of the arc segment between two adjacent straight bars (continuous value). As long as it is within the tolerance error range, docking can be achieved without being limited by fixed discrete angles, thus improving the flexibility of the marine train in missions. Furthermore, after docking, the hull (lock body) can slide along the arc-shaped rod without stress concentration, avoiding overall structural deformation. Compared with existing docking schemes that rely on high-precision visual guidance, this invention has a larger tolerance error range during docking, which is the length of the arc segment between two adjacent straight bars on the arc-shaped rod. The docking tolerance error range is also larger, and the docking tolerance error can be adjusted through structural design (theoretically, the larger the distance between two adjacent straight bars, the larger the docking tolerance error), significantly improving the robustness of single docking success under disturbed water surfaces.

[0018] (2) As a preferred option, since the tolerance error of the butt joint is the length of the arc segment between two adjacent straight bars on the arc bar, the straight bars are designed to have three points: the two ends of the arc bar plus the midpoint. This not only ensures the bending resistance of the arc bar, but also ensures that the tolerance error of the butt joint is large enough.

[0019] (3) As a preferred option, the shape of the arc rod is designed according to the spline curve, which can ensure the smoothness of the hull sliding process in the connected state.

[0020] (4) Furthermore, an array of grooves adapted to the width of the lock body is provided on the extension plate body, which facilitates the adjustment of the target position after the final hull docking (the lock body slides in different arc segments, affecting the target position after the final hull docking) during actual design or use, and also facilitates the positioning of the female head welding.

[0021] (5) Preferably, the extension plate body is set on the top of the unmanned vessel body. The extension plate body is a cuboid shell that can completely cover the hull of the unmanned vessel. On the one hand, it can reduce its own weight and material consumption, and on the other hand, it can reserve additional expansion space for the unmanned vessel, where batteries, cameras and other expansion modules can be stored. Furthermore, after all the unmanned vessels are docked, the platform structure formed by splicing the extension plates of each unmanned vessel can also serve as a sea platform.

[0022] (6) Preferably, the male head bar-shaped structure and the female head impact-type self-locking structure are made of stainless steel to ensure their bending resistance and corrosion resistance. The extension plate body is made of high-strength PE material to ensure its impact resistance and to prevent the mass from being too large and affecting the hull performance.

[0023] (7) Preferably, the male docking head, the female docking head, and the extension plate body are all rigidly connected to the hull, so there is no need to consider the displacement between the extension structure or the male and female docking heads and the hull caused by swaying, heaving, etc.

[0024] (8) Preferably, the collision surface of the arc-shaped bar and the locking tongue is designed to be arc-shaped, which can ensure a larger tolerance range for docking error in the direction perpendicular to the impact.

[0025] (9) Furthermore, the unmanned surface vessel docking control method of the present invention adopts a three-stage hierarchical state machine control strategy, which controls the independent navigation stage, the heading angle fine-tuning stage and the target docking stage respectively, greatly reducing the dependence on the terminal control accuracy of the unmanned surface vessel and significantly improving the robustness of a single docking success under disturbed water surface.

[0026] In summary, this invention overcomes the shortcomings of existing technologies, such as the high success rate of autonomous docking of unmanned surface vessels being greatly affected by sea state disturbances, the difficulty in balancing robustness and structural characteristics after docking, and the low efficiency of multi-vessel tandem expansion. It can achieve highly robust single docking and efficient and flexible multi-vessel swarm expansion capabilities. Attached Figure Description

[0027] Figure 1 A schematic diagram of the docking male structure provided in the bow of an unmanned surface vessel according to an embodiment of the present invention; Figure 2 A schematic diagram of the docking head in the closed state provided in an embodiment of the present invention, located at the stern of an unmanned surface vessel; Figure 3 A schematic diagram of the docking head in the open state provided in an embodiment of the present invention, located at the stern of an unmanned surface vessel; Figure 4 This is a schematic diagram of the structure of the expansion board body provided in an embodiment of the present invention; Figure 5 A schematic diagram showing the overall structural state of the extended plate connection after longitudinal bow-to-stern docking of the unmanned surface vessel provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure after the docking female head of the preceding unmanned surface vessel and the docking male head of the following unmanned surface vessel are docked, as provided in an embodiment of the present invention. Figure 7 The flowchart illustrates the control logic of multiple USVs transitioning from a discrete state to a connected state, thus realizing a maritime train, as provided in this embodiment of the invention.

[0028] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-Matching male head, 2-Matching female head, 3-Extension plate body, 11-Arc-shaped bar, 12-Straight bar, 21-Lock body, 22-Lock tongue, 23-Lock body groove, 24-Collision surface, 31-Groove array. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0030] Example 1 This invention provides a marine train extension structure for an unmanned surface vessel (USV). The structure includes a male docking head 1 located at the bow of the USV, a female docking head 2 located at the stern of the USV, and an extension plate body 3 mounted on the USV body. The male docking head 1 is located at the bow of the USV and is used to dock with the female docking head 2 located at the stern of the preceding USV. The male docking head 1 includes an arc-shaped rod 11 as its main body and multiple straight rods 12. The multiple straight rods 12 are arranged along the guiding direction of the arc-shaped rod 11 (the extension direction of the smooth arc of the arc-shaped rod itself, from one end point of the arc-shaped rod to the other end point), and all the multiple straight rods 12 extend outward along the same side of the arc-shaped rod 11. The multiple straight rods support the arc-shaped rod and also limit the docking tolerance range. Each straight rod has a connector at its end for connecting to the extension plate body on its own USV.

[0031] The docking female head includes at least one impact-type self-locking structure, which is connected to the extension plate body on its own unmanned surface vessel (USV) by welding. The impact-type self-locking structure includes a lock body 21 and a locking tongue 22 with an internal lock body. When the two USVs are docked longitudinally bow to stern, the arc-shaped bar 11 located in the docking male head 1 at the bow of the latter USV collides with the locking tongue 22. At this time, the locking tongue 22 automatically retracts into the lock body 21 along the collision surface 24 to open the lock, allowing the arc-shaped bar 11 to enter the lock body groove 23 radially. Afterward, the locking tongue 22 automatically closes due to gravity or elastic force, achieving the impact-type self-locking effect. After all USVs are docked, a maritime train is realized.

[0032] This invention designs a novel marine train extension structure, achieving longitudinal bow-to-stern docking of unmanned surface vessels (USVs) through the cooperation of an arc-shaped rod structure and an impact-type self-locking structure. Compared to existing self-correcting mechanisms, this invention, with straight bars on the arc-shaped rod, allows for a tolerance range where the arc-shaped rod enters the locking body groove radially, and the distance the locking body (hull) slides along the arc-shaped rod after entering the groove is the length of the arc segment between two adjacent straight bars. As long as the tolerance range is within the acceptable range, docking can be achieved without being limited by fixed discrete angles, thus improving the flexibility of the marine train in missions. Furthermore, after docking, the hull (lock) can slide along the arc-shaped rod without stress concentration, preventing overall structural deformation. Compared to existing docking schemes that rely on high-precision vision guidance, this invention has a larger tolerance range during docking—the length of the arc segment between two adjacent straight bars on the arc-shaped rod—and this tolerance range can be adjusted through structural design (theoretically, the larger the distance between two adjacent straight bars, the larger the tolerance range), significantly improving the robustness of successful single docking in turbulent water.

[0033] Preferably, since the presence of the straight bars will hinder the sliding of the female connector (lock body) on the curved bar, the docking tolerance error is the length of the curved segment between two adjacent straight bars on the curved bar. Therefore, the straight bars are designed to be provided at three positions: both ends and the midpoint of the curved bar. This design not only ensures the bending resistance of the curved bar, but also ensures that the docking tolerance error (the acceptable range of docking error) is sufficiently large, and the hull will slide along the curved steel bar to a fixed position after each docking. Figure 1 shows the structure of the docking male connector arranged at the bow of the unmanned boat. The main body of the docking male connector is a curved rod-shaped structure, and three straight bars are connected to the curved bar for support.

[0034] Preferably, the shape of the curved bar used for the male connector can be designed according to a spline curve, which can ensure the smoothness of the hull sliding process in the connected state. In the embodiment of the present invention, the shape of the curved bar is designed as a cubic spline curve according to the three points where the straight bars are located, and the cubic spline curve expression is: ; where S(x) represents the function of the shape of the curved bar, the plane coordinates of the connection points between the three straight bars and the curved bar are respectively P0(x0,y0), P1(x1,y1), P2(x2,y2), and x0<x1<x2. The guiding contour of the curved bar is defined on the interval [x0,x2], wherein the wider the boat, the larger [x0,x2] is. The coefficients a1, b1, c1, d1, a2, b2, c2, d2 are uniquely determined by the following system of equations: Interpolation conditions: ; First derivative continuity condition: ; Second derivative continuity condition: ; Natural boundary conditions: .

[0035] Figure 2 and Figure 3 respectively show the structures of the docking female connector arranged at the stern of the unmanned boat in the closed and open states. The docking female connector adopts an impact self-locking structure. The embodiment of the present invention uses a cage-type impact safety lock structure, which is connected to the expansion plate body by welding. The structure is divided into two parts: a lock body and a lock tongue. The lock tongue is located in the lock body, made of stainless steel, with small thickness, high strength and low corrosion tendency. The collision surface between the curved bar and the lock tongue is designed as a curved surface, which can ensure a larger acceptable error range in the vertical direction (the direction perpendicular to the impact direction). When the curved bar contacts the lock tongue, the curved bar of the male connector slides to the end of the lock tongue through force decomposition so as to open the lock. When the curved bar fully enters the groove of the lock body, the lock tongue is automatically closed under the action of gravity or the spring force to achieve the self-locking effect, so as to resist the vertical docking position deviation caused by waves.

[0036] Preferably, the extension plate body 3 is set on the top of the unmanned surface vessel body. The extension plate body is a cuboid shell that can completely cover the hull of the unmanned surface vessel, and has connection points with the male bow, female bow and hull of the unmanned surface vessel itself. Figure 4 The structure of the expansion plate body is shown. In this embodiment of the invention, the connection point with the male end is a screw hole; the connection point with the female end is a groove array 31 designed according to the size of the cage-type impact safety lock structure (the width of the lock body), which facilitates adjustment of the final sliding position after docking of the hull during actual design or use, and also facilitates the positioning for welding the female end; the connection point with the hull is four cylinders located at the four corners, which can be connected by drilling holes in the hull, but care must be taken to ensure that the connection is tightly sealed after connection to prevent water from entering the hull. The shell-shaped structure of the expansion plate body is designed to reduce its own weight and material consumption, and to reserve additional expansion space for the unmanned surface vessel (USV), where batteries, cameras, and other expansion modules can be stored; furthermore, after all USVs are docked, the expansion plate bodies of each USV are spliced ​​together to form a platform structure, which can also serve as a marine platform.

[0037] Preferably, the male head rod-shaped structure and the female head impact-type self-locking structure are made of stainless steel to ensure their bending resistance and corrosion resistance. The extension plate body is made of high-strength PE material (such as HDPE, UHMWPE, UHMW-PE, etc.) to ensure its impact resistance strength and to prevent its mass from being too large to affect the hull performance.

[0038] In this embodiment of the invention, the male docking head, the female docking head, and the extension plate body are all rigidly connected to the hull. Therefore, there is no need to consider the displacement between the extension structure or the male / female docking head and the hull caused by swaying, heaving, or other conditions.

[0039] Figure 5 The overall connection status of the expansion board is displayed. Figure 6 The diagram shows the structure after the docking female head of the preceding unmanned surface vessel (USV) docks with the docking male head of the following USV.

[0040] Example 2 This invention provides a docking control method for an unmanned surface vessel (USV) using the marine train extension structure described in Embodiment 1. This control method employs a three-stage hierarchical state machine, including: During the independent navigation phase, all USVs proceed in parallel to their respective initial target points, which are all aligned on a straight line, and the target heading angle of each USV is also in the direction indicated by the line. Each vessel operates independently, using A... The algorithm outputs the planned path; and adjusts A based on the deviation between the current path point and the initial target point, and the deviation between the current heading angle and the target heading angle. The algorithm outputs the planned path. The current heading angle is determined by the USV's real-time position obtained from the positioning device, the USV's velocity obtained from the pose sensor, and the angular velocity.

[0041] During the heading angle fine-tuning phase, when the USV is less than the preset distance from its initial target point, the USV triggers fine-tuning, relaxes the position tolerance, and prioritizes ensuring that the hull is aligned with the target with a more accurate heading angle. The fine-tuning algorithm can automatically detect the error trend of the angle (heading angle). Based on the heading angle deviation at this time, an adaptive PID controller with anti-integral saturation is used to output differential thrust, so as to achieve slow forward movement while fine-tuning the heading angle, so that the USV is facing the target heading angle direction. In addition, through the stability judgment mechanism, it is determined that the USV has reached the initial target point only after a certain number of stable judgments are reached.

[0042] In the static target docking phase, once all USVs reach the initial target point and are all facing the target heading angle, their current poses are recorded. The unmanned surface vessels then sequentially dock longitudinally end-to-end. After docking, the USVs move, and the hulls (lock bodies) slide along the arc-shaped guide bar under tension, eventually all USVs sliding towards the target position, thus forming a complete "sea train" formation. In this embodiment of the invention, docking begins with the last USV, proceeding sequentially to achieve docking. After docking is complete, forward movement is triggered sequentially starting with the first USV, until all USVs finally slide towards the target position.

[0043] In this embodiment of the invention, A The path cost evaluation function of the algorithm is: f(n) = g(n) + h(n); Where n represents the path node currently being evaluated, f(n) is the estimated total cost from the starting node to the target node via node n, g(n) is the actual cost incurred from the starting node to node n, and h(n) is the heuristic estimated cost from node n to the target node.

[0044] An adaptive PID controller that resists integral saturation is: ; Where the discrete control period is k, the controller output is u(k) (referring to differential thrust), e(k) is the system error of the current control period (referring to heading angle deviation), T is the control period time, and K is the differential thrust. p K i K d These are the proportional, integral, and differential gain coefficients for the current cycle, respectively. sat (k) is the effective integral term after anti-integral saturation treatment, and its update law is defined as: ; Among them, anti-saturation activator Determined by the following formula: ; Among them, [u min ,u max [ ] represents the effective output range of the thruster.

[0045] The adaptive adjustment of the gain coefficient can be based on the absolute value of the error e(k), for example, using the following piecewise function relationship: ; Among them, K p,base K i,base K d,base β is the preset base gain value. p β i β d It is an adjustable adaptive intensity coefficient.

[0046] The present invention relates to a marine train extension structure and control scheme for unmanned surface vessels (USVs). Through a self-locking structure of "arc-bar-impact safety lock" and a three-stage hierarchical state machine control strategy, it significantly reduces the dependence on the terminal control precision of the USV and substantially improves the robustness of successful single docking under disturbed water conditions. The relaxed design at the connection point (the tolerance error during docking is the length of the arc segment between two adjacent straight bars on the arc-bar, which is a continuous value, and the lock body can slide between the arc-bar and the arc-bar) allows the extended "marine train" to both resist external loads as a whole and effectively buffer and disperse internal stresses caused by waves, avoiding structural damage. This structure supports modular tandem docking, enabling the efficient and flexible construction of large-scale marine mobile platforms adapted to different mission requirements.

[0047] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A marine train extension structure for unmanned surface vessels, characterized in that, include: The male docking head (1) is located at the bow of the unmanned surface vessel (USV) and the female docking head (2) is located at the stern of the USV. The male connector (1) includes an arc-shaped rod (11) as the main body and multiple straight rods (12) arranged along the arc-shaped rod (11), and the multiple straight rods (12) all extend outward along the same side of the arc-shaped rod (11); the female connector (2) includes at least one impact-type self-locking structure, the impact-type self-locking structure includes a lock body (21) and a built-in lock tongue (22). When the unmanned surface vessels (USVs) are docked longitudinally, the arc-shaped bar (11) in the male docking head (1) of the latter USV collides with the locking tongue (22) in the female docking head (2) of the former USV, causing the locking tongue (22) to retract into the lock body (21), so that the arc-shaped bar (11) enters the lock body (21) radially. Then, the locking tongue (22) automatically closes under its own gravity or elastic force, realizing impact-type self-locking. After all USVs are docked, they move and slide along the guide of the arc-shaped bar (11) under the action of tension to slide to the target position, realizing the sea train. The guide sliding distance is the length of the arc segment between two adjacent straight bars (12) on the arc-shaped bar (11).

2. The marine train extension structure for unmanned surface vessels according to claim 1, characterized in that, include: The multi-segment straight rod (12) consists of three segments (12), which are the two ends of the arc-shaped rod (11) and the midpoint of the arc-shaped rod (11).

3. The marine train extension structure for unmanned surface vessels according to claim 2, characterized in that, The guide profile of the arc-shaped rod (11) is determined by using a cubic spline curve based on the planar coordinates of the connection point between the three straight rods (12) and the arc-shaped rod (11).

4. The marine train extension structure for unmanned surface vessels according to any one of claims 1-3, characterized in that, It also includes an extension plate body (3) set on the hull of the unmanned vessel, and the ends of the multiple straight bars (12) are also provided with connectors, which are connected to the extension plate body (3) on the hull of the unmanned vessel; the extension plate body (3) is also provided with a groove array (31) adapted to the width of the lock body (21), and the lock bodies (21) of each impact-type self-locking structure are respectively welded to the groove array (31) on the hull of the unmanned vessel.

5. The marine train extension structure for unmanned surface vessels according to claim 4, characterized in that, The extension plate body (3) is a cuboid shell that completely covers the hull of the unmanned vessel and is located on the top of the hull of the unmanned vessel.

6. The marine train extension structure for unmanned surface vessels according to claim 4, characterized in that, The male connector (1) and the female connector (2) are made of stainless steel; the extension plate body (3) is made of PE material with a strength exceeding a preset threshold.

7. The marine train extension structure for unmanned surface vessels according to claim 4, characterized in that, The male docking head (1), the female docking head (2), and the expansion plate body (3) are all rigidly connected to the unmanned surface vessel.

8. The marine train extension structure according to any one of claims 1-3, characterized in that, The impact-type self-locking structure is a cage impact-type safety lock structure, and the collision surface between the arc-shaped bar (11) and the lock tongue (22) is an arc surface.

9. A docking control method for unmanned surface vessels based on a marine train extended structure, characterized in that, The marine train extension structure is the marine train extension structure according to any one of claims 1-8, and the unmanned surface vessel docking control method includes: During the independent navigation phase, all unmanned surface vessels (USVs) are controlled to proceed in parallel to their respective initial target points; wherein the initial target points are on a straight line and the target heading angles of all USVs point to the same straight line direction. During the heading angle fine-tuning phase, when the distance between the unmanned surface vessel and the initial target point is less than a preset distance, a fine-tuning algorithm is used to detect the current heading angle deviation. Based on the current heading angle deviation, an adaptive PID controller with anti-integral saturation is used to output differential thrust to fine-tune the current heading angle so that the current heading angle tends to the target heading angle. When the unmanned surface vessel reaches a certain number of stable discriminations, it is determined that the unmanned surface vessel has reached the initial target point. During the target docking phase, the unmanned vessels are docked longitudinally end to end in sequence. After all the unmanned vessels are docked, they move and slide along the arc-shaped guide bar under the pull force to slide towards the target position, thus realizing the sea train.

10. The unmanned surface vessel docking control method according to claim 9, characterized in that, During the independent navigation phase, based on the starting point, current path point, and initial target point of each unmanned surface vessel, A... The algorithm outputs a planned path so that the unmanned surface vessel can travel along the planned path to the initial target point; And adjust A based on the deviation between the current path point and the initial target point, and the current heading angle deviation. The algorithm outputs the planned path.

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