Berthing System

Abstract

To provide a docking system which can reduce processing load.SOLUTION: The docking system lets a ship 1 dock along a way line W as a navigation route for the ship 1 to dock. The docking system includes: an acquisition unit for acquiring information on the way line W input by a user; and a line trace control unit for controlling a line trace to cause the ship 1 to navigate from the point of start Ps to the point of end Pe of the way line W along the way line W.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a berthing system. [Background technology]

[0002] When docking a ship, the operator must safely and quickly berth the ship at the pier. However, because there is a risk of the ship colliding with other anchored ships, obstacles, the pier, etc., advanced techniques are required for docking.

[0003] Patent Document 1 describes a ship docking support system, which formulates a planned route to a docking position based on the ship state, constraint conditions, and disturbance conditions, and provides ship maneuvering information for sailing along the planned route. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-76537 Summary of the Invention [Problem to be solved by the invention]

[0005] In the docking support system of Patent Document 1, in order to formulate a planned route, a computer sets multiple waypoints to the docking position based on the ship state and constraint conditions, and formulates the planned route by simulating the ship maneuvering motion based on the ship state, constraint conditions, and disturbance conditions, which may increase the processing load on the computer.

[0006] The present disclosure describes a docking system that can reduce processing load. [Means for solving the problem]

[0007] A docking system according to one aspect of the present disclosure is a system for docking a ship along a wayline, which is a route for the ship to dock on. The docking system includes an acquisition unit that acquires information about the wayline input by a user, and a line tracing control unit that performs line tracing control to navigate the ship along the wayline from a start point to an end point of the wayline. [Effects of the Invention]

[0008] According to the present disclosure, the processing load can be reduced. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a functional block diagram of the berthing system. [Figure 2] FIG. 2 is a diagram showing an example of the hardware configuration of a computer that constitutes the docking system. [Figure 3] FIG. 3 is a flowchart showing a series of processes in the docking method performed by the docking system. [Figure 4] FIG. 4 is a diagram for explaining the setting of waylines. [Figure 5] FIG. 5 is a diagram for explaining line tracing control along a line segment connecting the initial position and the start point of the way line. [Figure 6] FIG. 6 is a diagram showing the navigation of a ship near the start point of a wayline. [Figure 7] FIG. 7 is a diagram for explaining line tracing control along a way line. [Figure 8] FIG. 8 is a diagram showing the navigation of a ship near the end of a wayline. [Figure 9] FIG. 9 is a diagram for explaining the azimuth control. [Figure 10] FIG. 10 is a diagram for explaining line tracing control using MPC (Model Predictive Control). DETAILED DESCRIPTION OF THE INVENTION

[0010] [1] Overview of the embodiment A docking system according to one aspect of the present disclosure is a system for docking a ship along a wayline, which is a route for the ship to dock on. The docking system includes an acquisition unit that acquires information about the wayline input by a user, and a line tracing control unit that performs line tracing control to navigate the ship along the wayline from a start point to an end point of the wayline.

[0011] In this docking system, a ship navigates from the start point of a wayline input by a user to the end point of the wayline. Because the wayline is input by the user, the docking system does not need to perform complex processing to determine the wayline. Therefore, it is possible to reduce the processing load of the docking system.

[0012] The docking system may further include a deceleration control unit that performs deceleration control to reduce the forward speed of the vessel when the distance from the vessel's position to the end point becomes equal to or less than a first threshold value due to line tracing control. In this case, when the vessel approaches the end point of the wayline, the forward speed of the vessel is reduced. Therefore, the vessel can be stopped at the end point of the wayline.

[0013] The first threshold value may be determined based on the forward speed of the vessel on the wayline. When the forward speed of the vessel is high, the sailing distance required to stop the vessel is longer than when the forward speed is low. In the above configuration, the first threshold value is determined taking the forward speed into consideration, and therefore the timing to start deceleration control is determined according to the forward speed. Therefore, it is possible to more reliably stop the vessel at the end point of the wayline.

[0014] The docking system may further include an azimuth control unit that turns the vessel so that the vessel is oriented at a predetermined azimuth angle when the forward speed of the vessel becomes equal to or less than the second threshold value due to the deceleration control. In this case, the vessel can be oriented at the predetermined azimuth angle at the end point of the wayline.

[0015] The docking system may further include a display control unit that causes a display device to display a screen that allows a user to input a wayline. The acquisition unit may acquire information about the wayline input on the screen. In this case, the user can directly input the wayline to the docking system.

[0016] If the vessel is located at a position different from the wayline, the line tracing control unit may cause the vessel to navigate from that position toward the starting point. In this case, there is no need to set a wayline from the vessel's current position. This relaxes the constraints for setting a wayline, allowing the user to set a wayline suitable for docking.

[0017] [2] Example of embodiment Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated description will be omitted.

[0018] A docking system according to one embodiment will be described with reference to Figures 1 and 2. Figure 1 is a functional block diagram of the docking system. Figure 2 is a diagram showing an example of the hardware configuration of a computer constituting the docking system. The docking system 10 shown in Figure 1 is a system for docking a ship along a wayline. The wayline is a route along which the ship docks. An example of the ship is an autonomous ship. The docking system 10 may be configured by one computer 100 (see Figure 2). The docking system 10 may be configured by multiple computers 100.

[0019] As shown in FIG. 2, the computer 100 constituting the docking system 10 includes a processor 101, a main memory device 102, an auxiliary memory device 103, an input device 104, a display device 105, and a communication device 106.

[0020] An example of the processor 101 is a CPU (Central Processing Unit). The main memory device 102 temporarily stores programs read from the auxiliary memory device 103 and calculation results by the processor 101. The main memory device 102 is composed of, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory). The auxiliary memory device 103 stores programs for configuring each functional component of the berthing system 10. The auxiliary memory device 103 is composed of, for example, a hard disk device or a flash memory, and generally has a capacity capable of storing a larger amount of data than the main memory device 102.

[0021] The input device 104 inputs information to hardware included in the computer 100. The input device 104 is composed of, for example, a keyboard, a mouse, a touch panel, and operation buttons. The display device 105 displays information output from hardware included in the computer 100. The display device 105 is composed of, for example, a display. The input device 104 and the display device 105 may be integrated, such as a touch panel. The communication device 106 performs data communication with other devices via a communication network in accordance with instructions from the processor 101. The communication device 106 is composed of, for example, a network interface card (NIC) or a wireless communication module.

[0022] Each functional component of the docking system 10 shown in FIG. 1 is realized by loading a predetermined computer program into hardware such as the main memory device 102, causing each piece of hardware to operate under the control of the processor 101, and reading and writing data from and to the main memory device 102 and the auxiliary memory device 103.

[0023] The docking system 10 includes, as functional components, a display control unit 11, an acquisition unit 12, an acquisition unit 13, a switching unit 14, a line tracing control unit 15, a deceleration control unit 16, and a direction control unit 17.

[0024] The display control unit 11 is a functional component that displays various information on the display device 105. The display control unit 11 outputs display information to the display device 105 for displaying a predetermined display screen, and the display device 105 displays the predetermined display screen based on the display information. The display control unit 11, for example, causes the display device 105 to display a screen for allowing the user to input setting information. The setting information is information about docking and includes information about waylines and an azimuth angle. The information about waylines includes position coordinates of the start point of the wayline and the end point of the wayline. The azimuth angle represents the direction of the ship (direction of the bow) when docking of the ship is complete. The azimuth angle is, for example, the angle between the north direction and the direction of the ship. The azimuth angle has a positive value clockwise, with north being 0 degrees. The setting information may further include a target speed.

[0025] The acquisition unit 12 is a functional component that acquires various information input by a user. The acquisition unit 12 acquires, for example, setting information. The acquisition unit 12 may also acquire a docking start instruction.

[0026] The acquisition unit 13 is a functional component that acquires state quantities of the ship. The state quantities of the ship are state quantities that indicate the sailing state of the ship. Examples of the state quantities include the ship's position information, direction of travel (heading), forward speed, lateral speed, and angular velocity. The acquisition unit 13 may further acquire disturbance information. The disturbance information is environmental information that affects the sailing of the ship. Examples of disturbance information include information about wind and tides.

[0027] The switching unit 14 is a functional component that switches the sailing mode of the vessel. The switching unit 14 switches the sailing mode by starting or stopping the line tracing control unit 15, the deceleration control unit 16, and the direction control unit 17 under predetermined conditions. The switching unit 14 outputs a signal that the vessel 1 has completed docking under predetermined conditions.

[0028] The line tracing control unit 15 is a functional component that performs line tracing control to navigate the vessel along a predetermined line. The predetermined line includes a wayline. The line tracing control unit 15 performs line tracing control using, for example, pure pursuit.

[0029] The deceleration control unit 16 is a functional component that performs deceleration control to reduce the forward speed of the vessel. The deceleration control unit 16 brings the forward speed of the vessel closer to zero. The deceleration control unit 16 performs deceleration control, for example, by rotating the propeller shaft in the reverse direction. The number of rotations for reverse rotation may be a constant value. An appropriate number of rotations is set depending on the vessel. The deceleration control unit 16 may also perform deceleration control by astern (astern) the vessel using a bucket. Note that the deceleration control unit 16 may bring not only the forward speed but also the lateral speed and azimuth speed closer to zero.

[0030] The heading control unit 17 is a functional component that controls the heading of the ship. The heading control unit 17 turns the ship so that the direction of the ship is the azimuth angle included in the setting information. Turning the ship means changing the direction of the bow on the spot. The heading control unit 17 turns the ship, for example, by rotating the ship around an axis of rotation perpendicular to the water surface.

[0031] Next, a docking method for a ship performed by the docking system 10 will be described with reference to Figs. 3 to 9. Fig. 3 is a flowchart showing a series of processes in the docking method performed by the docking system. Fig. 4 is a diagram for explaining the setting of a wayline. Fig. 5 is a diagram for explaining line tracing control along a line segment connecting an initial position and the start point of the wayline. Fig. 6 is a diagram showing navigation of a ship near the start point of the wayline. Fig. 7 is a diagram for explaining line tracing control along the wayline. Fig. 8 is a diagram showing navigation of a ship near the end point of the wayline. Fig. 9 is a diagram for explaining heading control.

[0032] A series of processes of the docking method shown in FIG. 3 is started, for example, when a user performs an operation to dock the ship 1. First, the display control unit 11 causes the display device 105 to display a setting screen (step S1). The setting screen is a screen for setting (inputting) setting information. For example, as shown in FIG. 4, the setting screen displays a map including the position of the ship 1 at the time of starting docking (initial position Po) and a docking location such as a pier. The display control unit 11 may determine the map to be included in the setting screen based on position information of the ship 1 acquired by, for example, a GPS (Global Positioning System). The position information of the ship 1 included in the state quantity acquired by the acquisition unit 13 may be used as the position information of the ship 1. On the setting screen, no-entry zones and obstacles may be displayed superimposed on the map.

[0033] Next, the acquisition unit 12 acquires setting information (step S2). The acquisition unit 12 acquires information about the wayline W set by the user on the setting screen and the azimuth angle θ as setting information. For example, the user sets the wayline W by specifying the start point Ps and end point Pe of the wayline W on the setting screen. The user may set the wayline W by drawing the wayline W on the setting screen. For example, the user sets the azimuth angle θ by specifying the attitude of the ship 1 at the time of docking using a ship icon on the setting screen. The user may also set the azimuth angle θ directly. The user may further set a target speed on the setting screen, and the acquisition unit 12 may further acquire the target speed as setting information. Then, the acquisition unit 12 outputs the setting information to the switching unit 14, the line tracing control unit 15, and the azimuth control unit 17.

[0034] Next, the acquisition unit 12 determines whether or not a docking start instruction has been acquired (step S3). For example, the acquisition unit 12 acquires the docking start instruction when the user performs an operation to start docking on the setting screen. If the acquisition unit 12 determines that the docking start instruction has not been acquired (step S3; NO), it repeats step S3 until the docking start instruction is acquired. On the other hand, if the acquisition unit 12 determines that the docking start instruction has been acquired (step S3; YES), it outputs the docking start instruction to the switching unit 14.

[0035] Next, the acquisition unit 13 acquires the state quantities and disturbance information of the ship 1 (step S4). While the series of processes of the docking method shown in FIG. 3 are being performed, the acquisition unit 13 periodically acquires the state quantities and disturbance information of the ship 1, but this is not shown in FIG. 3. The acquisition cycle of the state quantities and the acquisition cycle of the disturbance information may be the same or different. Alternatively, the acquisition unit 13 may acquire various types of information at the timing when that information is needed. Then, the acquisition unit 13 outputs the state quantities and disturbance information of the ship 1 to the switching unit 14, the line tracing control unit 15, the deceleration control unit 16, and the direction control unit 17.

[0036] Next, when the switching unit 14 receives the docking start command and the state quantity, it determines whether or not the initial position Po of the ship 1 is on the way line W (step S5). For example, the switching unit 14 determines that the initial position Po is on the way line W when the distance between the initial position Po and the way line W is smaller than the distance between the initial position Po and the start point Ps.

[0037] In step S5, if the switching unit 14 determines that the initial position Po is not on the way line W (step S5; NO), it outputs an instruction (execution instruction) to the line trace control unit 15 to perform line trace control along the line segment R. The line segment R is a line segment connecting the initial position Po and the start point Ps. Then, upon receiving the execution instruction, the line trace control unit 15 performs line trace control along the line segment R (step S6). Specifically, as shown in FIG. 5, the line trace control unit 15 navigates the vessel 1 from the initial position Po toward the start point Ps along the line segment R. In this embodiment, the target forward speed is set to forward speed v1. In other words, the line trace control unit 15 navigates the vessel 1 from the initial position Po toward the start point Ps while maintaining the forward speed v1. The line trace control unit 15 executes line trace control using, for example, pure pursuit.

[0038] When pure pursuit is used, the ship 1 is steered by the line trace control unit 15 as follows: t If it exists, the line trace control unit 15 calculates the position x t Position x slightly forward on line segment R t+1 The line tracing control unit 15 causes the ship 1 to navigate from the initial position Po toward the starting point Ps so that the ship 1 follows the line segment R by repeating the same maneuver. In pure pursuit, the ship 1 is controlled to return to the line segment R even if it deviates from the line segment R, so the line tracing control unit 15 may cause the ship 1 to navigate without using disturbance information.

[0039] Then, while line tracing control is being performed along the line segment R, the switching unit 14 compares the distance between the vessel 1 and the start point Ps with a threshold value Dth1 and determines whether the distance has become less than or equal to the threshold value Dth1. The switching unit 14 calculates the distance between the vessel 1 and the start point Ps based on the position information of the vessel 1 included in the state quantity of the vessel 1 and the position information of the start point Ps included in the setting information. The threshold value Dth1 is a threshold value used to determine the timing (position) at which the line used for line tracing control is switched from the line segment R to the way line W. The threshold value Dth1 is determined based on the forward speed v1.

[0040] For example, the turning radius of the vessel 1 may vary depending on the forward speed v1, the size of the vessel 1, and the like. Therefore, a relational expression between the forward speed v1 of the vessel 1 and the turning radius may be determined in advance and stored in a memory (not shown). In this case, the switching unit 14 calculates the turning radius of the vessel 1 from the forward speed v1 using the relational expression, and dynamically determines the threshold value Dth1 by adding a predetermined value to the turning radius. A predetermined fixed forward speed may be used as the forward speed v1. The fixed forward speed may be a forward speed used by a person when performing a docking operation. In this case, a threshold value Dth1 predetermined according to the forward speed v1 is stored in a memory (not shown), and the switching unit 14 uses the threshold value Dth1 stored in the memory.

[0041] Then, as shown in Fig. 6, when the distance between the vessel 1 and the start point Ps becomes equal to or less than the threshold value Dth1, the switching unit 14 outputs an instruction (switching instruction) to the line tracing control unit 15 to switch the line used for line tracing control from the line segment R to the way line W. Then, upon receiving the switching instruction, the line tracing control unit 15 performs line tracing control along the way line W (step S7). As a result, the vessel 1 turns from the line segment R toward the way line W. Thereafter, when the vessel 1 is positioned on the way line W, as shown in Fig. 7, the vessel 1 navigates along the way line W from the start point Ps toward the end point Pe.

[0042] In this embodiment, the target forward speed in the line tracing control along the wayline W is set to a forward speed v2. In other words, the line tracing control unit 15 navigates the vessel 1 from the start point Ps to the end point Pe while maintaining the forward speed v2. The forward speed v2 may be smaller or larger than the forward speed v1. The forward speed v2 may be the same as the forward speed v1.

[0043] In addition, if the initial position Po is on an extension of the wayline W, that is, if the initial position Po, starting point Ps, and ending point Pe are lined up in that order along the wayline W, the vessel 1 will navigate along each line in the order of line segment R and wayline W without turning.

[0044] In step S5, if the switching unit 14 determines that the initial position Po is on the way line W (step S5; YES), it outputs an instruction (implementation instruction) to the line tracing control unit 15 to perform line tracing control along the way line W. Then, upon receiving the implementation instruction, the line tracing control unit 15 performs line tracing control along the way line W (step S7). In other words, the line tracing control unit 15 navigates the vessel 1 from the initial position Po toward the end point Pe along the way line W.

[0045] While line tracing control is being performed along the wayline W, the switching unit 14 compares the distance between the vessel 1 and the end point Pe with a threshold value Dth2 (first threshold value) and determines whether the distance has become less than or equal to the threshold value Dth2. The switching unit 14 calculates the distance between the vessel 1 and the end point Pe based on the position information of the vessel 1 included in the state quantity of the vessel 1 and the position information of the end point Pe included in the setting information. The threshold value Dth2 is a threshold value used to determine the timing (position) for starting deceleration control. The threshold value Dth2 is determined based on the forward speed v2. As an example, the threshold value Dth2 is set to be equal to or greater than the sum of the distance (braking distance) that the vessel 1 moves forward in the deceleration control in step S8 described below, the distance that the vessel 1 moves forward in the heading control in step S9 described below, and the length from the axis of rotation used to turn the vessel 1 to the bow.

[0046] The forward distance in steps S8 and S9 may vary depending on the forward speed v2, the weight of the vessel 1, and the like. Therefore, a relational expression between the forward speed v2 of the vessel 1 and the sum of the forward distances in steps S8 and S9 may be determined in advance and stored in a memory (not shown). In this case, the switching unit 14 calculates the sum from the forward speed v2 using the relational expression, and dynamically determines the threshold value Dth2 by adding the length from the rotation axis to the bow and a predetermined value to the sum. A predetermined fixed forward speed may be used as the forward speed v2. The fixed forward speed may be a forward speed used by a person when performing a docking operation. In this case, a threshold value Dth2 predetermined according to the forward speed v2 is stored in a memory (not shown), and the switching unit 14 uses the threshold value Dth2 stored in the memory.

[0047] Then, as shown in FIG. 8, when the distance between the vessel 1 and the end point Pe becomes equal to or less than the threshold value Dth2, the switching unit 14 outputs an instruction to stop the line tracing control (stop instruction) to the line tracing control unit 15 and outputs an instruction to perform deceleration control (execution instruction) to the deceleration control unit 16. Then, upon receiving the stop instruction, the line tracing control unit 15 stops the line tracing control. Upon receiving the execution instruction, the deceleration control unit 16 performs deceleration control (step S8). In step S8, the deceleration control unit 16 reduces the forward speed v2 of the vessel 1 to bring the forward speed v2 closer to zero. At this time, since the vessel 1 may have a lateral velocity component and an azimuth angular velocity component, the deceleration control unit 16 reduces not only the forward speed v2 but also the lateral velocity and the azimuth angular velocity to bring these velocity components closer to zero. Note that when external disturbances are taken into consideration, the deceleration control unit 16 corrects the target rotation speed when rotating the engine in reverse, for example, to cancel the direction in which the external disturbance acts on the vessel 1.

[0048] While deceleration control is being performed, the switching unit 14 compares the forward speed v2 of the vessel 1, which is included in the state quantity of the vessel 1, with a threshold value vth (second threshold value), and determines whether the forward speed v2 has become equal to or less than the threshold value vth. The threshold value vth is a threshold value used to determine the timing to start azimuth control. The threshold value vth is determined in advance and stored in a memory (not shown). As an example, the threshold value vth is set to a value that will not affect (damage) the vessel 1 even if the vessel 1 collides with a pier or a wharf when docking.

[0049] Then, in response to the forward speed v2 of the vessel 1 becoming equal to or less than the threshold value vth, the switching unit 14 outputs an instruction to stop the deceleration control (stop instruction) to the deceleration control unit 16, and outputs an instruction to perform the azimuth control (execution instruction) to the azimuth control unit 17. Then, upon receiving the stop instruction, the deceleration control unit 16 stops the deceleration control. Upon receiving the execution instruction, the azimuth control unit 17 performs the azimuth control (step S9). In step S9, the azimuth control unit 17 turns the vessel 1 so that the orientation of the vessel 1 becomes the azimuth angle θ included in the setting information.

[0050] While the azimuth control is being performed, the switching unit 14 compares the difference between the direction (azimuth angle) of the vessel 1 included in the state quantity of the vessel 1 and the azimuth angle θ with a threshold value θth, and determines whether the difference is equal to or smaller than the threshold value θth. The threshold value θth is determined in advance and stored in a memory (not shown). As an example, the threshold value θth is an angle that allows a rope for mooring the vessel 1 to be handed over to a pier or the like.

[0051] 9, when the difference between the heading of the ship 1 and the azimuth angle θ becomes equal to or less than the threshold value θth, the switching unit 14 outputs an instruction to stop the azimuth control (stop instruction) to the azimuth control unit 17, and outputs information indicating the completion of docking to the display control unit 11. Then, upon receiving the stop instruction, the azimuth control unit 17 stops the azimuth control. Upon receiving the information indicating the completion of docking, the display control unit 11 displays on the display device 105 that the docking of the ship 1 has been completed, and notifies the user of the completion of docking (step S10). This completes the series of processes of the docking method.

[0052] As described above, in the docking system 10, the ship 1 navigates from the start point Ps of the wayline W to the end point Pe along the wayline W input by the user. A setting screen for allowing the user to input the wayline W is displayed on the display device 105, and the wayline W is set by the user on the setting screen. For example, no-entry areas may be set around the docking location, or obstacles may exist. The user can check the no-entry areas and obstacles on the setting screen and set the wayline W to avoid these. In this way, since the user directly inputs the wayline W to the docking system 10, the docking system 10 does not need to perform complex processing to determine the wayline W. This makes it possible to reduce the processing load on the docking system 10.

[0053] For example, if there is a no-entry zone or the like between the initial position Po of the ship 1 and the docking location, it is not possible to set the wayline W from the initial position Po. In contrast, in the docking system 10, if the initial position Po is located at a position different from the wayline W, the line tracing control unit 15 causes the ship 1 to navigate from the initial position Po toward the start point Ps of the wayline W. Therefore, there is no need to set the wayline W from the initial position Po of the ship 1. Therefore, the constraints for setting the wayline W are relaxed, allowing the user to set a wayline W that is suitable for docking.

[0054] The deceleration control unit 16 performs deceleration control in response to the fact that the distance from the position of the vessel 1 to the end point Pe becomes equal to or less than the threshold value Dth2 due to the line tracing control. Therefore, when the vessel 1 approaches the end point Pe of the way line W, the vessel 1 is decelerated. Therefore, the vessel 1 can be stopped at the end point Pe of the way line W.

[0055] When the forward speed v2 of the vessel 1 is high, the navigating distance required to stop the vessel 1 becomes longer compared to when the forward speed v2 is low. In the above embodiment, the threshold value Dth2 is determined taking the forward speed v2 into consideration, and therefore the timing to start deceleration control is determined in accordance with the forward speed v2. This makes it possible to more reliably stop the vessel 1 at the end point.

[0056] When the forward speed v2 becomes equal to or less than the threshold value vth due to the deceleration control, the azimuth control unit 17 turns the vessel 1 so that the vessel 1 is oriented at the azimuth angle θ. Therefore, it is possible to align the vessel 1 with the azimuth angle θ at the end point Pe of the wayline W.

[0057] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments.

[0058] In the above embodiment, the forward speed v1 and the forward speed v2 are each a constant speed, but may be changed as the vessel 1 sails. For example, the forward speed v1 may be set to a high speed at the start of the line tracing control along the line segment R, and may be reduced as the vessel 1 moves forward (approaching the start point Ps). Similarly, the forward speed v2 may be set to a high speed at the start of the line tracing control along the wayline W, and may be reduced as the vessel 1 moves forward (approaching the end point Pe). This configuration makes it possible to shorten the time required for docking.

[0059] The docking system 10 does not need to be equipped with the deceleration control unit 16. The user may set the wayline W and the target speed so that the ship 1 docks by inertia from the end point Pe of the wayline W. In this configuration, the docking system 10 does not need to perform deceleration control, which can further reduce the processing load.

[0060] The docking system 10 does not need to be equipped with the azimuth control unit 17. In this case, the user does not need to input the azimuth angle θ on the setting screen. In this configuration, the docking system 10 does not need to perform azimuth control, which can further reduce the processing load.

[0061] The line tracing control unit 15 may correct the target speed and the target angle so as to cancel the direction in which the disturbance acts on the vessel 1. An example of a method for correcting the target angle will be described below.

[0062] The line tracing control unit 15 corrects the target angle depending on whether the position of the vessel 1 is within a predetermined range relative to the target position (here, line segment R) or outside that range. Specifically, when the position of the vessel 1 is outside the range, the line tracing control unit 15 calculates the deviation ΔP of the current position of the vessel 1 from line segment R in the lateral direction (the direction perpendicular to line segment R) and the lateral velocity v of the vessel 1. Then, the line tracing control unit 15 calculates the correction angle Δφ using equation (1). Note that constants A and B are predetermined. In order to avoid a sudden change in the target angle, the upper limit of the correction angle Δφ is set to 5 degrees, and the lower limit is set to -5 degrees.

number

[0063] Then, when a predetermined execution condition is satisfied, the line trace control unit 15 calculates the target angle φ(t+1) at time t+1 by adding the correction angle Δφ to the target angle φ(t) at time t.

[0064] On the other hand, when the position of the vessel 1 is within the above range, the line tracing control unit 15 calculates the lateral force and moment that the vessel 1 receives from the wind and tidal current. For example, the line tracing control unit 15 calculates the lateral force and moment that the vessel 1 receives from the wind speed, wind direction, and the heading of the bow of the vessel 1. Similarly, the line tracing control unit 15 calculates the lateral force and moment that the vessel 1 receives from the tidal current speed, tidal current direction, and the heading of the bow of the vessel 1. Then, the line tracing control unit 15 calculates the lateral force that occurs when controlling the heading under the wind and tidal current by dividing the sum of the wind moment and the tidal current moment by the distance from the center of gravity of the vessel 1 to the rudder stock. Then, the line tracing control unit 15 calculates the target heading as the heading at which the sum of the lateral forces calculated from the wind lateral force, tidal current lateral force, and moment becomes zero (is canceled out).

[0065] The line tracing control unit 15 may execute line tracing control using MPC (Model Predictive Control) instead of pure pursuit. MPC is a method for controlling the navigation of the ship 1 while predicting the trajectory of the ship 1 based on a motion model of the ship 1. MPC will be described with reference to FIG. 10. FIG. 10 is a diagram for explaining line tracing control using MPC. In the example shown in FIG. 10, the ship 1 moves to a position x that is different from the line segment R at time t. t exists in.

[0066] First, the line tracing control unit 15 uses a motion model of the ship 1 to calculate the control input u t+k (k is 0 to 4) is input. t+k The rudder angle, engine speed, etc. are used as the yaw rate. Specifically, the motion model of the ship 1 includes the position x of the ship 1 at time t. t and control input u t By inputting the above, the position x of ship 1 at time t+1 can be calculated. t+1 Similarly, the position x of ship 1 at times t+2 to t+5 is calculated. t+2 ~x t+5 is calculated. As a result, the predicted trajectory L1 is obtained.

[0067] Then, the line trace control unit 15 evaluates whether the predicted trajectory L1 is an optimal trajectory using an evaluation function and a constraint function. As the constraint function, for example, a constraint function for avoiding obstacles and a constraint function for defining the usable range of the hardware (engine output, rudder angle, etc.) of the ship 1 are used. If the predicted trajectory L1 is not optimal, the line trace control unit 15 adjusts the control input u t+k is slightly changed to obtain the new control input u t+k The trajectory of Ship 1 is predicted again when

[0068] By repeating the above process, an optimal predicted trajectory L2 is obtained. Then, the line trace control unit 15 calculates the control input u used to obtain the predicted trajectory L2. t+kis the control input used for the actual control of the vessel 1.

[0069] By using MPC, the ship 1 can be navigated so as to satisfy constraint conditions. For example, when a constraint function for avoiding an obstacle is used, line tracing control can be performed while avoiding the obstacle. Furthermore, by using a disturbance model, line tracing control can be performed taking disturbances into consideration. [Explanation of symbols]

[0070] 1 ship 10 Berthing System 11 Display control unit 12 Acquisition Department 15 Line tracing control section 16 Deceleration control section 17 Direction control unit 105 Display device Pe end point Ps starting point W Wayline θ Azimuth

Claims

1. A berthing system for berthing a ship along a wayline, which is a route for the ship to berth, an acquisition unit that acquires information about the wayline input by a user, the information including the position coordinates of the start point of the wayline; a line tracing control unit that performs line tracing control to cause the vessel to navigate along the wayline from the start point to the end point of the wayline; A berthing system comprising:

2. 2. The docking system according to claim 1, further comprising a deceleration control unit that performs deceleration control to reduce the forward speed of the vessel in response to the distance from the position of the vessel to the end point becoming equal to or less than a first threshold value due to the line tracing control.

3. The docking system according to claim 2 , wherein the first threshold value is determined based on the forward speed on the wayline.

4. 4. The docking system according to claim 2, further comprising an azimuth control unit that turns the vessel so that the orientation of the vessel becomes a predetermined azimuth angle in response to the forward speed becoming equal to or less than a second threshold value due to the deceleration control.

5. a display control unit that displays a screen on a display device that allows the user to input the wayline; 5. The docking system according to claim 1, wherein the acquisition unit acquires information about the wayline input on the screen.

6. The docking system according to any one of claims 1 to 5, wherein the line tracing control unit, when the vessel is at a position different from the wayline, causes the vessel to navigate from the position toward the starting point.

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