Self-reconfiguration unmanned surface vehicle docking method

Abstract

The invention discloses a docking method for a self-reconfiguration unmanned surface vehicle, and aims to solve the problem that the docking success rate is low due to the fact that the existing unmanned surface vehicle adopts a self-reconfiguration sub-module static docking mode and cannot ensure the stability of docking positions and postures when encountering wind, waves and flow. According to the position of a target boat receiving a docking instruction and various data of the target boat and a tracking boat, a steering elliptical region, a deceleration elliptical region and a docking circle region are obtained; in each area, a virtual target point is selected by using a selection strategy according to the relative position of the target boat and the tracking boat, an expected path is generated according to the virtual target point and the real-time position of the target boat, the tracking boat sails along the expected path, and butt joint of the target boat and the tracking boat can be achieved when sailing is finished. The invention belongs to the technical field of unmanned ship autonomous docking control.

Description

Technical Field

[0001] The present invention relates to the technical field of autonomous docking control of unmanned surface vessels, and particularly to a docking method for a self-reconfigurable unmanned surface vessel. Background Art

[0002] As a new type of marine equipment in recent years, Unmanned Surface Vehicles (USV) have broad application prospects and important research value due to their high speed, intelligence, and unmanned characteristics. However, a single unmanned surface vessel has limitations when performing complex tasks. Therefore, the concept of a self-reconfigurable unmanned surface vessel has been proposed. By connecting the bows and sterns of multiple unmanned surface vessels together to form a longer parallel middle body, the wave-making resistance can be reduced and the endurance can be increased. The autonomous docking control technology is one of the core technologies to achieve this concept.

[0003] In the prior art, the docking process of a self-reconfigurable unmanned vessel adopts a static docking method for self-reconfigurable sub-modules, that is, the target vessel needs to maintain a static state. This method has a very high docking success rate in still water. However, when encountering wind, waves, and currents, the sub-modules cannot ensure the stability of the docking position and attitude, resulting in a low docking success rate. Therefore, a new docking planning method is needed, which can achieve the dynamic docking of a self-reconfigurable unmanned vessel, dynamically adjust the docking path according to the sailing speed of the unmanned surface vessel, and during the docking process, the target vessel can always maintain a moving state. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that when the existing unmanned surface vessel adopts the static docking method for self-reconfigurable sub-modules, it cannot ensure the stability of the docking position and attitude when encountering wind, waves, and currents, resulting in a low docking success rate, and a docking method for a self-reconfigurable unmanned surface vessel is proposed.

[0005] The technical solution adopted by the present invention is as follows:

[0006] It includes the following steps:

[0007] S1. Set the position of the target vessel when it receives the docking instruction as the center of the ellipse. According to the center of the ellipse and various data of the target vessel and the tracking vessel, obtain the steering ellipse area, deceleration ellipse area, and docking circle area;

[0008] S2. In each area obtained in S1, according to the relative position of the target vessel and the tracking vessel, select a virtual target point using a selection strategy, generate a desired path based on the virtual target point and the real-time position of the target vessel, and the tracking vessel sails according to the desired path. When the sailing ends, the docking of the target vessel and the tracking vessel is achieved.

[0009] Further, the various data of the target boat and the tracking boat in S1 include the navigation speed of the tracking boat, the length of the target boat, and the angle between the navigation path of the tracking boat and the horizontal line.

[0010] Further, the expression of the steering ellipse region in S1 is:

[0011]

[0012] where k1 is a parameter, k1 is 0.5 - 0.75, L is the length of the target boat, v3 is the real-time navigation speed of the tracking boat in the steering ellipse region, a3 is the major axis of the steering ellipse region, b3 is the minor axis of the steering ellipse region, θ3 is the angle between the navigation path of the tracking boat in the steering ellipse region and the major axis direction of the steering ellipse, and kn is a knot, which is a speed unit.

[0013] Further, the expression of the deceleration ellipse region in S1 is:

[0014]

[0015] where v2 is the real-time navigation speed of the tracking boat in the deceleration ellipse region, a2 is the major axis of the deceleration ellipse region, b2 is the minor axis of the deceleration ellipse region, and θ2 is the angle between the navigation path of the tracking boat in the deceleration ellipse region and the major axis direction of the deceleration ellipse.

[0016] Further, the expression of the docking circle region in S1 is:

[0017]

[0018] where R1 is the radius of the docking circle region, v1 is the navigation speed of the tracking boat in the docking circle region, and θ1 is the angle between the navigation path of the tracking boat in the docking circle region and the direction of the target boat's length.

[0019] Further, in each region obtained in S1 in S2, according to the relative positions of the target boat and the tracking boat, a virtual target point is selected using a selection strategy, and an expected path is generated based on the virtual target point and the real-time position of the target boat. The tracking boat sails according to the expected path, and when the sailing ends, the docking of the target boat and the tracking boat is achieved. The specific process is as follows:

[0020] In the steering ellipse region, the angle between the line connecting the target boat and the tracking boat and the major axis direction of the steering ellipse is obtained according to the relative positions of the target boat and the tracking boat, and it is determined whether the angle between the line connecting the target boat and the tracking boat and the major axis direction of the steering ellipse is greater than θ3. If it is greater than θ3, a point on the steering ellipse whose angle between the line connecting it and the real-time position of the target boat and the major axis direction of the steering ellipse is θ3 is selected as the virtual target point 1. Otherwise, the intersection point of the line connecting the target boat and the tracking boat and the steering ellipse is selected as the virtual target point 1. After determining the virtual target point 1, the tracking boat is linearly connected to the virtual target point 1 to obtain the desired path 1, and the tracking boat sails according to the desired path 1;

[0021] After the tracking boat reaches the virtual target point 1, it is determined whether the angle between the line connecting the virtual target point 1 and the target boat and the major axis direction of the deceleration ellipse is greater than θ2. If it is greater than θ2, a point on the deceleration ellipse whose angle between the line connecting it and the real-time position of the target boat and the major axis direction of the deceleration ellipse is θ2 is selected as the virtual target point 2. Otherwise, the intersection point of the line connecting the target boat and the tracking boat and the deceleration ellipse is selected as the virtual target point 2. After determining the virtual target point 2, the tracking boat is linearly connected to the virtual target point 2 to obtain the desired path 2, and the tracking boat sails according to the desired path 2;

[0022] After the tracking boat reaches the virtual target point 2, it is determined whether the angle between the line connecting the virtual target point 2 and the target boat and the direction of the target boat's length is greater than θ1. If it is greater than θ1, a point on the docking circle whose angle between the line connecting it and the real-time position of the target boat and the direction of the target boat's length is θ1 is selected as the virtual target point 3. Otherwise, the intersection point of the line connecting the target boat and the tracking boat and the docking circle is selected as the virtual target point 3. After determining the virtual target point 3, the tracking boat is linearly connected to the virtual target point 3 to obtain the desired path 3, and the tracking boat sails according to the desired path 3. When the sailing ends, the docking of the target boat and the tracking boat is achieved.

[0023] Furthermore, the speed change of the tracking boat on the desired path 2 and the deceleration process before approaching are constrained, and the expression is:

[0024]

[0025] where V max is the sailing speed of the tracking boat when it reaches the virtual target point 2, d is the real-time distance from the tracking boat to the docking position, and α is a constant coefficient.

[0026] Furthermore, when the tracking boat enters the deceleration ellipse region, its sailing speed is maintained between 4 knots and 6 knots.

[0027] The beneficial effects of the present invention are:

[0028] In the present invention, the traditional concentric circle docking planning method is improved to a dynamically adaptive elliptical path based on speed. According to various data of the target boat and the tracking boat, a heading adjustment elliptical area, a deceleration elliptical area, and a docking circle area are constructed. The present invention fully considers the speed change of the tracking boat during navigation and the navigation direction of the target boat. The major axis size of each elliptical area is dynamically adjusted in real time according to the speed change of the tracking boat during navigation to determine the real-time heading adjustment ellipse, deceleration ellipse, and docking circle. The tracking boat adjusts its heading within the heading adjustment ellipse to ensure that its heading is close to the navigation direction of the target boat, laying a foundation for subsequent deceleration and docking. The tracking boat needs to complete the deceleration task before docking within the deceleration ellipse to control its speed approaching the target boat, which can effectively prevent the docking failure or even damage to the device caused by untimely deceleration and excessive collision of the docking device. The tracking boat needs to perform the final approach operation within the docking circle area to ensure that it can accurately dock onto the target boat. The tracking boat in the present invention realizes docking with the target boat through autonomous heading adjustment and gradual deceleration. This method improves the efficiency and success rate of autonomous docking between surface unmanned boats in the actual marine environment. Moreover, during the docking process, the target boat can always be in a moving state, realizing more efficient and accurate path planning and docking control.

[0029] Meanwhile, the present invention significantly improves the flexibility, adaptability, and docking success rate of path planning. In addition, when planning the docking path of the tracking boat, after finding the virtual target points of each elliptical area through a selection strategy, the expected path of the tracking boat is obtained. The tracking boat is set to sail along the expected path and approach the target boat sailing in a straight line, making the driving path smoother. When approaching the target boat, the speeds of the two are relatively stationary, ensuring the successful docking of the tracking boat and the docking boat and improving the docking success rate of the unmanned boat.

[0030] The present invention takes into account high efficiency, safety, and robustness, and can adapt to scenarios such as variable-speed navigation of the target boat and multi-boat cooperation in complex sea conditions, providing a better solution for autonomous docking of unmanned boats. Description of the Drawings

[0031] Figure 1 It is a schematic diagram of the target boat, the heading adjustment elliptical area, the deceleration elliptical area, and the docking circle area;

[0032] Figure 2 It is a schematic diagram of the expected path generation area;

[0033] Figure 3 It is a flow chart for selecting virtual target points;

[0034] Figure 4 It is a simulation diagram of the docking process of the unmanned boat;

[0035] Figure 5 It is a schematic diagram of the docking device on the target boat;

[0036] Figure 6 It is a schematic diagram of the docking device on the pursuit boat;

[0037] Figure 7 It is a simulation diagram of the target boat equipped with the docking device;

[0038] Figure 8 It is a simulation diagram of the pursuit boat equipped with the docking device; Specific implementation manner

[0039] Specific implementation manner 1: As Figure 1-8 shown, a self-reconfiguring surface unmanned boat docking method in this implementation manner, the specific process is as follows:

[0040] S1: Set the position of the target boat when it receives the docking instruction as the center of the ellipse. According to the center of the ellipse and various data of the target boat and the pursuit boat, obtain the steering ellipse area, deceleration ellipse area, and docking circle area. The specific process is as follows:

[0041] The various data include the navigation speed of the pursuit boat, the length of the target boat, and the angle between the navigation path of the pursuit boat and the horizontal line. The various data are provided by the self-reconfiguring unmanned boat sub-module. The sub-module refers to a minimum task calculation unit with a pair of target boats and pursuit boats. Therefore, when it comes to the docking tasks of multiple unmanned boats, the overall task distribution reconstruction and calculation arrangement are carried out with this minimum task calculation unit.

[0042] In this implementation plan, combined with Figure 1 for illustration, within each ellipse area, the pursuit boat needs to complete the steering, deceleration, and approaching processes in sequence to achieve the preparatory work before the pursuit boat docks with the target boat.

[0043] (1) Steering ellipse area

[0044] The setting of the steering ellipse area aims to maintain a good docking angle between the pursuit boat and the target boat, enabling the pursuit boat to freely adjust its bow direction within this area to ensure that the heading of the pursuit boat is consistent with the navigation direction of the target boat, laying the foundation for subsequent deceleration and docking. At the same time, the steering ellipse area leaves room for the pursuit boat to handle unexpected situations, facilitating subsequent adjustment or cancellation of the current docking task. Even if the pursuit boat cannot adjust the bow angle to the target range here, there will be sufficient space for re-adjustment or cancellation of the current docking task and returning to the original position to start over. Therefore, starting from the above two aspects and combining how to improve the docking success rate, the present invention proposes to adjust the major axis size of the steering ellipse in real time according to the navigation speed of the pursuit boat, so that the pursuit boat has more space to turn. To ensure the smooth progress of the docking process, the constraint settings of the steering ellipse area need to be adjusted according to the actual approach experience of the pursuit boat, and these constraint settings help to optimize the docking path.

[0045] The expression for the steering ellipse region is as follows:

[0046]

[0047] Among them, k1 is a parameter used to restrict the major axis of the ellipse from being too long. Generally, k1 ranges from 0.5 to 0.75. L is the length of the target boat, v3 is the real-time navigation speed of the tracking boat in the steering ellipse region, a3 is the major axis of the steering ellipse region, b3 is the minor axis of the steering ellipse region, θ3 is the angle between the navigation path of the tracking boat in the steering ellipse region and the direction of the major axis of the steering ellipse, and kn is a knot, which is a speed unit. The above constraint on θ3 enables the tracking boat to maintain a good angle before docking, ensuring that the angle difference between the tracking boat and the target boat is not large, and only a small adjustment is required to successfully complete the docking after approaching.

[0048] (2) Deceleration ellipse region

[0049] The tracking boat enters the deceleration ellipse region to complete the deceleration task before docking, so as to control its speed approaching the target boat and avoid excessive collision of the docking device due to too high a speed, thereby avoiding docking failure or equipment damage. Therefore, the main control objective in the deceleration ellipse region of the present invention is set to reduce the navigation speed of the tracking boat and complete a small-angle steering process.

[0050] The expression for the deceleration ellipse region is as follows:

[0051]

[0052] Among them, v2 is the real-time navigation speed of the tracking boat in the deceleration ellipse region, a2 is the major axis of the deceleration ellipse region, b2 is the minor axis of the deceleration ellipse region, and θ2 is the angle between the navigation path of the tracking boat in the deceleration ellipse region and the direction of the major axis of the deceleration ellipse.

[0053] For small unmanned boats, it usually takes about 30 meters to reduce the speed from the maximum speed of 6 kn to 0. However, considering that the unmanned boat needs a certain residual speed during the docking process and its speed cannot be completely zero, therefore, the present invention sets a constraint range for the major axis of the deceleration ellipse. While ensuring that the shape of the deceleration ellipse is adjusted in real time according to the navigation speed of the tracking boat, it prevents the size of the deceleration ellipse from being larger than that of the steering ellipse, thus ensuring the stability and effectiveness of the docking process. Such a setting not only optimizes the deceleration path of the unmanned boat but also provides a guarantee for successful docking. In addition, setting the central angle range for the tracking boat to enter the deceleration ellipse region is to further constrain the heading direction after roughly adjusting the heading direction within the steering ellipse, so as to ensure that the tracking boat has a better navigation angle, making the angle between the tracking boat and the docking device of the target boat not much different during docking, thereby controlling the tracking boat to complete the docking under low relative speed conditions. The low relative speed means that both the tracking boat and the target boat are at a relatively low navigation speed and the relative speed between them is close to 0.

[0054] (3) Docking circle area

[0055] The tracking boat performs the final approach operation within the docking circle area to ensure that it can accurately dock onto the target boat. During this process, the tracking boat needs to make fine adjustments to ensure that its position and attitude match those of the target boat. After the heading adjustment and deceleration adjustment, the tracking boat needs to reduce its relative speed to 0 m / s as much as possible before finally reaching the docking position. At the same time, control the bow of the tracking boat to be close to the docking device. The docking device of the target boat is generally set at the center (bow tip) or slightly upper position at the stern, which is convenient for the tracking boat to dock from the rear. The docking device of the tracking boat is located at the bow and is arranged in the area directly in front of the bow using a telescopic arm or a guiding device. To ensure the feasibility and flexibility of the docking operation, the radius of the circular operation area required during the docking process in the present invention is set to the length of the target boat. When the tracking center point is within the docking circle area, start to control the tracking boat to decelerate. At the same time, by further reducing the heading and speed of the tracking boat, gradually reduce the absolute value of the heading angle, which improves the docking success rate of the unmanned surface boat.

[0056] The expression of the docking circle area is:

[0057]

[0058] Among them, R1 is the radius of the docking circle area, v1 is the navigation speed of the tracking boat in the docking circle area, and θ1 is the included angle between the navigation path of the tracking boat in the docking circle area and the longitudinal direction of the target boat's length.

[0059] The present invention respectively restricts the above three areas to ensure that the sizes of the steering ellipse area and the deceleration ellipse area are adjusted in real time according to the navigation speed of the tracking boat, and restricts the navigation speed and navigation range of the tracking boat in the three areas, which improves the accuracy and safety when the target boat and the tracking boat dock, thereby enhancing the autonomous docking ability of the tracking boat in a complex navigation environment.

[0060] S2: In each area obtained in S1, according to the relative positions of the target boat and the tracking boat, a virtual target point is dynamically selected using a selection strategy. An expected path is generated based on the virtual target point and the real-time position of the target boat. The tracking boat sails according to the expected path, and when the sailing ends, the docking of the target boat and the tracking boat is achieved. The specific process is as follows:

[0061] In the steering ellipse region, based on the relative positions of the target boat and the tracking boat, the angle between the line connecting the target boat and the tracking boat and the major axis direction of the steering ellipse is obtained, and it is determined whether the angle between the line connecting the target boat and the tracking boat and the major axis direction of the steering ellipse is greater than θ3. If it is greater than θ3, a point on the steering ellipse whose angle between the line connecting it and the real-time position of the target boat and the major axis direction of the steering ellipse is θ3 is selected as the virtual target point 1. Otherwise, the intersection point of the line connecting the target boat and the tracking boat and the steering ellipse is selected as the virtual target point 1. After determining the virtual target point 1, the tracking boat is linearly connected to the virtual target point 1 to obtain the desired path 1, and the tracking boat sails according to the desired path 1.

[0062] After the tracking boat reaches the virtual target point 1, it is determined whether the angle between the line connecting the virtual target point 1 and the target boat and the major axis direction of the deceleration ellipse is greater than θ2. If it is greater than θ2, a point on the deceleration ellipse whose angle between the line connecting it and the real-time position of the target boat and the major axis direction of the deceleration ellipse is θ2 is selected as the virtual target point 2. Otherwise, the intersection point of the line connecting the target boat and the tracking boat and the deceleration ellipse is selected as the virtual target point 2. After determining the virtual target point 2, the tracking boat is linearly connected to the virtual target point 2 to obtain the desired path 2, and the tracking boat sails according to the desired path 2.

[0063] After the tracking boat reaches the virtual target point 2, it is determined whether the angle between the line connecting the virtual target point 2 and the target boat and the direction of the target boat's length is greater than θ1. If it is greater than θ1, a point on the docking circle whose angle between the line connecting it and the real-time position of the target boat and the direction of the target boat's length is θ1 is selected as the virtual target point 3. Otherwise, the intersection point of the line connecting the target boat and the tracking boat and the docking circle is selected as the virtual target point 3. After determining the virtual target point 3, the tracking boat is linearly connected to the virtual target point 3 to obtain the desired path 3, and the tracking boat sails according to the desired path 3. When the sailing ends, the docking of the target boat and the tracking boat is achieved.

[0064] In this implementation scheme, it is described in combination with Figure 2 and Figure 3 . After obtaining the real-time positions of the tracking boat and the target boat in each ellipse region, a desired path generation region is generated around the target boat, and virtual target points are generated within the desired path generation region. The desired path generation region is the region above the red line in Figure 2 . By setting different angles θ in different regions in the present invention i , the boundary points TL and TR of the sailing region of the tracking boat in the steering ellipse region, the boundary points JL and JR of the sailing region of the tracking boat in the deceleration ellipse region, and the boundary points DL and DR of the sailing region of the tracking boat in the docking circle region are determined, ensuring that while the tracking boat sails along the desired path in each ellipse region, the angle between its sailing route and the target boat remains relatively small. The desired path is based on being within this region, ensuring that the tracking boat can sail relatively stably to near the target boat to complete the docking.

[0065] Since the steering ellipse area is only used to adjust the navigation angle of the tracking boat, the docking circle area is only used for docking, and the deceleration ellipse area is used for deceleration to achieve the final docking, the speed of the tracking boat in the deceleration ellipse area is particularly important. Therefore, the present invention sets the desired speed on the desired path 2 within the deceleration ellipse area. According to the speed of the tracking boat at the virtual target point 2, the real-time major axis size of the deceleration ellipse, and the real-time distance from the tracking boat to the target boat, the speed change of the tracking boat and the deceleration process before approaching are constrained, so that the tracking boat can quickly reduce its speed to a very low level within the deceleration ellipse area, ensuring that the tracking boat decelerates to slightly higher than the speed of the target boat to meet the speed requirements of the docking circle area.

[0066] The expression for constraining the speed change of the tracking boat and the deceleration process before approaching on the desired path 2 is:

[0067]

[0068] Among them, V max is the speed of the tracking boat when it reaches the virtual target point 2, d is the real-time distance from the tracking boat to the docking position, and α is a constant coefficient.

[0069] In the present invention, it is required that the speed of the tracking boat when entering the deceleration ellipse area be maintained between 4 knots and 6 knots, and maintain a very low relative speed and slow down slowly when reaching within the docking ellipse.

[0070] In this implementation scheme, it is described in combination with Figure 4 For illustration, Figure 4 In it, Usv2a represents the initial position of the tracking boat, Usv2b represents the process of the tracking boat adjusting the bow angle in the steering ellipse, Usv2c represents the deceleration process of the tracking boat in the deceleration ellipse and slightly adjusts the bow direction, Usv2s represents the docking position of the tracking boat, Usv1a represents the initial position of the target boat, and Usv1s represents the docking position of the target boat. The present invention ensures that the tracking boat accurately approaches the target boat along the steering ellipse area, deceleration ellipse area, and docking circle area in sequence by optimizing the speed and bow direction of the tracking boat in real time, and completes the docking. In the environmental simulation, this method can better control the unmanned boat to complete the path planning task, and can also quickly and stably execute the task after turning at each virtual target point. At the same time, the tracking boat can successfully sail along the desired path and approach the target boat sailing in a straight line, providing the correct position environment for the docking device to work and achieving successful and efficient docking.

Claims

1. A docking method for a self - reconstructing unmanned surface vehicle, characterized in that: It includes the following steps: S1. Set the position of the target boat when it receives the docking instruction as the center of the ellipse. According to the center of the ellipse and various data of the target boat and the tracking boat, obtain the steering ellipse area, deceleration ellipse area, and docking circle area; S2. In each area obtained in S1, according to the relative positions of the target boat and the tracking boat, use a selection strategy to select a virtual target point. Generate an expected path based on the virtual target point and the real-time position of the target boat. The tracking boat sails according to the expected path, and the docking of the target boat and the tracking boat is achieved when the sailing ends.

2. The self-reconfiguring surface unmanned boat docking method according to claim 1, characterized in that: The various data of the target boat and the tracking boat in S1 include the sailing speed of the tracking boat, the length of the target boat, and the angle between the sailing path of the tracking boat and the horizontal line.

3. The self-reconfiguring surface unmanned boat docking method according to claim 1, wherein: The expression of the steering ellipse area in S1 is: where k1 is a parameter, k1 ranges from 0.5 to 0.75, L is the length of the target boat, v3 is the real-time sailing speed of the tracking boat in the steering ellipse area, a3 is the major axis of the steering ellipse area, b3 is the minor axis of the steering ellipse area, θ3 is the angle between the sailing path of the tracking boat in the steering ellipse area and the major axis direction of the steering ellipse, and kn is a knot, which is a speed unit.

4. The self-reconfiguring surface unmanned boat docking method according to claim 1, characterized in that: The expression of the deceleration ellipse area in S1 is: where v2 is the real-time sailing speed of the tracking boat in the deceleration ellipse area, a2 is the major axis of the deceleration ellipse area, b2 is the minor axis of the deceleration ellipse area, and θ2 is the angle between the sailing path of the tracking boat in the deceleration ellipse area and the major axis direction of the deceleration ellipse.

5. A self-reconfiguring unmanned surface vehicle docking method according to claim 1, characterized in that: The expression of the docking circle area in S1 is: where R1 is the radius of the docking circle area, v1 is the sailing speed of the tracking boat in the docking circle area, and θ1 is the angle between the sailing path of the tracking boat in the docking circle area and the direction of the length of the target boat.

6. A self-reconfiguring unmanned surface vehicle docking method according to claim 1, characterized in that: In S2, in each area obtained in S1, according to the relative positions of the target boat and the tracking boat, use a selection strategy to select a virtual target point. Generate an expected path based on the virtual target point and the real-time position of the target boat. The tracking boat sails according to the expected path, and the docking of the target boat and the tracking boat is achieved when the sailing ends. The specific process is as follows: In the steering ellipse area, obtain the angle between the line connecting the target boat and the tracking boat and the major axis direction of the steering ellipse according to the relative positions of the target boat and the tracking boat. Determine whether the angle between the line connecting the target boat and the tracking boat and the major axis direction of the steering ellipse is greater than θ3. If it is greater than, select the point on the steering ellipse whose angle between the line connecting it and the real-time position of the target boat and the major axis direction of the steering ellipse is θ3 as the virtual target point 1. Otherwise, select the intersection point of the line connecting the target boat and the tracking boat and the steering ellipse as the virtual target point 1. After determining the virtual target point 1, connect the tracking boat and the virtual target point 1 linearly to obtain the expected path 1. The tracking boat sails according to the expected path 1; After the tracking boat reaches the virtual target point 1, it determines whether the angle between the line connecting the virtual target point 1 and the target boat and the major axis direction of the deceleration ellipse is greater than θ2. If it is greater than θ2, a point on the deceleration ellipse where the angle between the line connecting the real-time position of the target boat and the major axis direction of the deceleration ellipse is θ2 is selected as the virtual target point 2. Otherwise, the intersection point of the line connecting the target boat and the tracking boat and the deceleration ellipse is selected as the virtual target point 2. After determining the virtual target point 2, the tracking boat is linearly connected to the virtual target point 2 to obtain the desired path 2, and the tracking boat sails according to the desired path 2; After the tracking boat reaches the virtual target point 2, it determines whether the angle between the line connecting the virtual target point 2 and the target boat and the direction of the target boat's length is greater than θ1. If it is greater than θ1, a point on the docking circle where the angle between the line connecting the real-time position of the target boat and the direction of the target boat's length is θ1 is selected as the virtual target point 3. Otherwise, the intersection point of the line connecting the target boat and the tracking boat and the docking circle is selected as the virtual target point 3. After determining the virtual target point 3, the tracking boat is linearly connected to the virtual target point 3 to obtain the desired path 3, and the tracking boat sails according to the desired path 3. When the sailing ends, the docking of the target boat and the tracking boat is achieved.

7. A self-reconfiguring surface unmanned boat docking method according to claim 6, characterized in that: Constraints are imposed on the speed change of the tracking boat on the desired path 2 and the deceleration process before approaching, and the expression is: Among them, V max is the speed of the tracking boat when it reaches the virtual target point 2, d is the real-time distance from the tracking boat to the docking position, and α is a constant coefficient.

8. A self-reconfiguring unmanned surface vehicle docking method according to claim 7, characterized in that: The speed of the tracking boat when entering the deceleration ellipse area remains between 4 knots and 6 knots.

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