Automatic guidance method for ships, automatic guidance program for ships, automatic guidance system for ships, and ships

Abstract

To provide an automatic guidance method for a vessel, an automatic guidance program for a vessel, an automatic guidance system for a vessel, and a vessel, capable of controlling deviation from a planned route to a certain deviation or less even if disturbance occurs without the necessity of a large amount of calculation.SOLUTION: An automatic guidance method for a vessel using an automatic steering device at least carrying out automatic steering of a traveling vessel includes: a planned route generation step S1 for acquiring a planned route or carrying out calculation for the planned route; a vessel information acquirement step S3 for acquiring a position of the vessel and bow orientation; a pure pursuit calculation step S4 for calculating a target point fulfilling a prescribed condition on a planned route in the proceeding direction of the vessel or calculating orientation of the target point based on the position and the bow orientation; an automatic steering calculation step S5 for calculating the steering angle of the vessel based on the target point or the orientation, and the position or the bow orientation; and a control step S6 for controlling the automatic steering device based on the calculated steering angle.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an automatic ship guidance method using an automatic ship steering device that automatically steers at least a sailing ship, an automatic ship guidance program, an automatic ship guidance system, and a ship. [Background technology]

[0002] Berthing is one of the most demanding ship maneuvers for crew members, and requires advanced maneuvering skills even at low speeds. Normally, when a ship is traveling at low speeds, maneuverability deteriorates due to a decrease in rudder pressure, and the ship is more susceptible to disturbances such as wind and currents, so berthing generally requires high skill. Meanwhile, in recent years, coastal shipping has been facing serious problems such as a shortage of experienced crew members and an aging crew.

[0003] Here, Patent Document 1 discloses an automatic steering device that includes a route calculation unit that calculates a turning route for the ship based on the positions of each of a plurality of target points, an indirect target point calculation unit that calculates an indirect target point ahead of the ship, a command rudder angle calculation unit that calculates a command rudder angle based on the positional relationship between the turning route and the indirect target point, and a steering control unit that controls the steering mechanism of the ship based on the command rudder angle. Patent Document 2 also discloses an automatic steering method for turning from the current route at a constant turn rate and changing course (varying course) to a new route, in which a way-changing point is determined on the current route from the turn rate and ship speed, a way-changing line that passes through this way-changing point and is parallel to the new route is determined, and once the ship passes this way-changing line, a course change based on the turn rate is initiated, and when it is determined that a more accurate course change can be achieved by switching to course-keeping control, which corrects the course heading based on the amount of course deviation from the route, rather than by changing course based on the turn rate, the method switches from course change based on the turn rate to course-keeping control. Furthermore, Patent Document 3 discloses a ship steering system that records in advance in a controller a route based on predetermined position information, as well as ship steering operations related to changes in engine speed and rudder direction on the route, and automatically navigates a ship based on the recorded route and ship steering operations. Furthermore, Patent Document 4 discloses an automatic steering device for a ship in which, when the ship operator switches to automatic steering using the display unit of the automatic steering device, the control unit of the automatic steering device takes in the ship's bow direction and position at that time, calculates a set course and set heading, and thereafter takes in the ship's bow direction and position at each time as needed, calculates the heading deviation between the set course and set heading, and based on this, calculates a command rudder angle to control the rudder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-196103 [Patent Document 2] Japanese Patent Application Publication No. 7-242199 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-184846 [Patent Document 4] Japanese Patent Application Laid-Open No. 2011-16384 Summary of the Invention [Problem to be solved by the invention]

[0005] There has been much research into the automation of berthing maneuvers, including those using optimal control theory, neural networks and PD controllers, and evolutionary computation. However, to resolve various issues such as the difficulty of system design, the real-time performance of control calculations, cost, and safety, there is a need to develop a simpler controller that can be applied to general ships consisting of a rudder and propeller. Here, in Patent Document 1, it is necessary to calculate the arc-shaped turning course that the ship will take when changing course, and to calculate the command rudder angle based on the positional relationship with the indirect target point, which makes the calculations complicated. Furthermore, Patent Document 2 aims to improve the accuracy when changing course from the current course to the new course, but does not aim to make the current course or the new course follow the planned course with high accuracy. Furthermore, Patent Document 3 describes that while the ship is automatically navigating based on a set route, the navigational status of the ship is detected using a rudder angle sensor, a throttle sensor, a GPS device, and a heading sensor, and feedback control is performed, but does not describe in detail how feedback control is performed based on the detected navigational status. Furthermore, Patent Document 4 automatically controls the ship to navigate along a set route based on the deviation between the heading and position of the ship and the set heading and route, which results in complex calculations. Therefore, the present invention aims to provide an automatic guidance method for a ship, an automatic guidance program for a ship, an automatic guidance system for a ship, and a ship that can suppress deviation from a planned route to a certain level even in the presence of disturbances without requiring a large amount of calculation. [Means for solving the problem]

[0006] The automatic guidance method for a ship according to claim 1 is an automatic guidance method for a ship using an automatic ship steering device that automatically steers at least the sailing ship. , total a planned route generation process for calculating a planned route; Ship position 、 heading , and the speed of said vessel A vessel information acquisition process for acquiring the above information; Ship Position, heading , and the speed A pure pursuit calculation process for calculating a target point or a direction of the target point that satisfies a predetermined condition on the planned route in the traveling direction of the ship based on the target point or the direction of the target point, Ship an automatic ship maneuvering calculation process for calculating a steering angle of the ship based on the position or the heading; at least and a control process for controlling the automatic ship-steering device based on the calculated steering angle. In the planned route generation process, the planned route is divided into a first route segment controlled in a route following mode, a second route segment controlled in a neutral navigation mode, a third route segment controlled in a heading mode, and a fourth route segment controlled in a stop mode, using the input docking position coordinates that are the arrival position of the ship and the docking azimuth angle that is the arrival orientation, and the position, heading, and speed of the ship acquired in the ship information acquisition process, and the third route segment is generated so that the approach angle of the ship to the arrival position becomes a predetermined angle when the distance between the position of the ship and the arrival position reaches a predetermined distance, and the fourth route segment is generated so as to include an approximately straight line for performing speed control so that the speed of the ship becomes zero when the distance between the position of the ship and the arrival position reaches a position shorter than the predetermined distance. It is characterized by: According to the present invention as set forth in claim 1, by combining control based on pure pursuit calculations (pure pursuit control) with an automatic ship steering device and performing automatic guidance to follow a planned route, control can be performed without requiring a large amount of calculation, and deviation from the planned route can be suppressed to a certain level even in the presence of disturbances. In particular, pure pursuit control makes it easy to follow a planned route that has curved sections when combined with an automatic ship steering device such as an autopilot.

[0007] The present invention as defined in claim 2 is In the control process, the straight-line distance D from the ship to the arrival position berth is a first distance D which is a straight-line distance from the arrival position to a boundary position between the first segment route and the second segment route. 1 a first distance determination step of determining whether the straight-line distance D to the arrival position is greater than berth is the first distance D 1 If it is determined that the distance is less than or equal to the straight-line distance D berth is a second distance D, which is a straight-line distance to a boundary position between the second segment route and the third segment route. 2 a second distance determination step of determining whether the straight-line distance D berth is the second distance D 2 If it is determined that the distance is less than or equal to the straight-line distance D berth is a third distance D, which is a straight-line distance to a boundary position between the third segment route and the fourth segment route. 3 and a third distance determination step for determining whether the straight-line distance D to the arrival position is greater than berth is the first distance D 1 If it is determined that the distance is greater than the predetermined distance, the control is performed in the path following mode, and in the second distance determination process, the straight-line distance D berth is the second distance D 2 If it is determined that the distance is greater than the neutral navigation mode, the third distance determination process determines that the distance is greater than the neutral navigation mode. berth is the third distance D 3 If it is determined that the speed is greater than the turning speed, the control is performed in the turning mode. It is characterized by: According to the present invention as set forth in claim 2, the ship can be made to follow the planned route with higher accuracy depending on the speed.

[0008] Claim 3 The present invention is characterized in that, in the process of generating a planned route, sea area information is acquired and information on unnavigable sea areas is taken into account in calculating the planned route. Claim 3 According to the present invention described above, the safety of the automatic guidance method for ships can be improved and the sea areas in which the automatic guidance method for ships can be applied can be expanded. Here, "unnavigable sea area information" refers to information about sea areas where navigation is not possible due to the presence of moving objects such as ships, obstacles such as floating objects, or shallow waters.

[0009] Claim 4The present invention described is characterized in that the speed at which the ship will navigate the planned route is calculated during the automatic ship steering calculation process, and in the control process, a speed control means including a clutch of the automatic ship steering device is controlled based on the calculated speed. Claim 4 According to the present invention described above, by adjusting the speed with a speed control means such as a clutch, it is possible to easily guide the ship to a destination point, including a berthing point, for example.

[0010] Claim 5 The present invention is characterized in that meteorological and oceanographic information around the ship is acquired during the ship information acquisition process, and the steering angle and speed are corrected during the automatic ship maneuvering calculation process by taking into account external forces on the ship based on the meteorological and oceanographic information. Claim 5 According to the present invention described above, the ship can be made to follow the planned route with higher accuracy by correcting the steering angle and speed by taking external forces into account.

[0011] Claim 6 The present invention described is characterized by determining the external forces on a ship due to wind direction and wind speed obtained as meteorological and oceanographic information, predicting the ship's motion due to the external forces, and deriving a steering angle or speed that will cancel out the ship's motion due to the external forces, thereby controlling an automatic ship steering device to compensate for wind disturbances. Claim 6 According to the present invention described above, deviation from the planned route can be suppressed to a certain level even during strong winds.

[0012] Claim 7 The automatic guidance program for a ship corresponding to the description is an automatic guidance program for a ship that uses an automatic ship steering device that automatically controls at least the steering of a sailing ship, and is characterized in that it causes a computer to execute a planned route generation process in accordance with input conditions, a ship information acquisition process, a pure pursuit calculation process, an automatic ship steering calculation process, and a control process in an automatic guidance method for a ship. Claim 7According to the present invention described above, by combining control based on pure pursuit calculations (pure pursuit control) with an automatic ship steering device and performing automatic guidance to follow a planned route, it is possible to provide a program that performs control without performing a large amount of calculations and suppresses deviation from the planned route to a certain level even in the presence of external disturbances.

[0013] Claim 8 In the automatic guidance system for ships corresponding to the description, it is an automatic guidance system for ships using an automatic ship steering device that automatically controls at least the steering of a sailing ship. , total a planned route generation means for calculating a planned route, and a position of the ship 、 heading , and the speed of said vessel and a vessel information acquisition means for acquiring the vessel position, the vessel heading, , and the speed a pure pursuit calculation means for calculating a target point or a direction of the target point that satisfies a predetermined condition on the planned route in the traveling direction of the ship based on the target point or the direction of the target point; Ship an automatic ship steering calculation means for calculating a steering angle of the ship based on the position or the heading; at least a control means for controlling the automatic ship steering device based on the steering angle of the ship; The planned route generation means generates the planned route divided into a first segmented route controlled in a route following mode, a second segmented route controlled in a neutral navigation mode, a third segmented route controlled in a heading mode, and a fourth segmented route controlled in a stop mode, using the input docking position coordinates, which are the arrival position of the ship, and the docking azimuth, which is the arrival orientation, of the ship, and the position, heading, and speed of the ship acquired by the ship information acquisition means, and generates the third segmented route so that the approach angle of the ship to the arrival position becomes a predetermined angle when the distance between the position of the ship and the arrival position reaches a predetermined distance, and generates the fourth segmented route so as to include an approximately straight line for performing speed control so that the speed of the ship becomes zero when the distance between the position of the ship and the arrival position reaches a position shorter than the predetermined distance. It is characterized by: Claim 8 According to the present invention described above, by combining control based on pure pursuit calculations (pure pursuit control) with an automatic ship steering device and performing automatic guidance to follow the planned route, control can be performed without requiring a large amount of calculation, and deviation from the planned route can be suppressed to a certain level even in the presence of external disturbances.

[0014] Claim 9 The present invention as described is The control means calculates the linear distance D from the ship to the arrival position. berth is a first distance D which is a straight-line distance from the arrival position to a boundary position between the first segment route and the second segment route. 1 a first distance determination means for determining whether the straight-line distance D to the arrival position is greater than berth is the first distance D 1 If it is determined that the distance is less than or equal to the straight-line distance D berth is a second distance D, which is a straight-line distance to a boundary position between the second segment route and the third segment route. 2 a second distance determination means for determining whether the straight-line distance D to the arrival position is greater than berth is the second distance D 2 If it is determined that the distance is less than or equal to the straight-line distance D berth is a third distance D, which is a straight-line distance to a boundary position between the third segment route and the fourth segment route. 3 and a third distance determining means for determining whether the straight-line distance D to the arrival position is greater thanberth is the first distance D 1 If it is determined that the distance is greater than the predetermined distance, the control is performed in the path following mode, and the second distance determination means determines that the distance is greater than the predetermined distance. berth is the second distance D 2 If it is determined that the distance is greater than the neutral navigation mode, the third distance determination means determines that the distance is greater than the neutral navigation mode. berth is the third distance D 3 If it is determined that the speed is greater than the turning speed, the control is performed in the turning mode. It is characterized by: Claim 9 According to the present invention described above, it is possible to make the ship follow the planned route more accurately depending on the speed.

[0015] Claim 10 The present invention is characterized in that the planned route generation means acquires sea area information and calculates the planned route taking into account information on unnavigable sea areas. Claim 10 According to the present invention described above, the safety of automatic guidance systems for ships can be improved and the sea areas in which automatic guidance systems for ships can be applied can be expanded.

[0016] Claim 11 The present invention is characterized in that an automatic ship steering calculation means calculates the speed at which the ship will navigate the planned route, and a control means controls a speed control means including a clutch of the automatic ship steering device so as to obtain the calculated speed. Claim 11 According to the present invention described above, by adjusting the speed with a speed control means such as a clutch, it is possible to easily guide the ship to a destination point, including a berthing point, for example.

[0017] Claim 12 The present invention is characterized in that the ship information acquisition means acquires weather and sea condition information around the ship, and the automatic ship maneuvering calculation means corrects the steering angle and speed by taking into account external forces on the ship based on the weather and sea condition information. Claim 12 According to the present invention described above, the ship can be made to follow the planned route with higher accuracy by correcting the steering angle and speed by taking external forces into account.

[0018] Claim 13The present invention described is characterized by determining the external forces on a ship due to wind direction and wind speed obtained as meteorological and oceanographic information, predicting the ship's motion due to the external forces, and deriving a steering angle or speed that will cancel out the ship's motion due to the external forces, thereby controlling an automatic ship steering device to compensate for wind disturbances. Claim 13 According to the present invention described above, deviation from the planned route can be suppressed to a certain level even during strong winds.

[0019] Claim 14 The present invention is characterized by comprising a display means for displaying at least one of the planned route, the position of the ship, the heading, the target point, or the direction of the target point. Claim 14 According to the present invention described above, crew members can check the planned route and monitor the operating status of the automatic guidance system.

[0020] Claim 15 A ship corresponding to the description is characterized by being equipped with an automatic ship guidance system. Claim 15 According to the present invention described above, it is possible to provide a ship equipped with an automatic guidance system that combines pure pursuit control and an automatic ship steering device, and that can accurately follow a planned route even in the presence of external disturbances. [Effects of the Invention]

[0021] According to the automatic guidance method for a ship of the present invention, by combining control based on pure pursuit calculations (pure pursuit control) with an automatic ship steering device, automatic guidance that follows a planned route can be performed without requiring a large amount of calculation, and deviation from the planned route can be suppressed to a certain level even in the event of disturbance. In particular, pure pursuit control makes it easy to follow a planned route that has curved sections when combined with an automatic ship steering device such as an autopilot.

[0022] In addition, if the ship's speed is obtained in the ship information acquisition process and calculations are performed using the speed in the pure pursuit calculation process and the automatic maneuvering calculation process, the ship can be made to follow the planned route more accurately depending on the speed.

[0023] In addition, in the planned route generation process, if the arrival position and arrival direction of the input ship's arrival point are obtained, and the position, heading, and speed obtained in the ship information acquisition process are used to calculate a planned route that can reach the arrival position and ensure the arrival direction, it is possible to generate a planned route that draws a smooth curve that connects to the arrival position in the direction (angle) of the arrival direction.

[0024] Furthermore, if sea area information is acquired during the planned route generation process and the planned route is calculated taking into account information on unnavigable sea areas, the safety of the automatic ship guidance method can be improved and the sea areas to which the automatic ship guidance method can be applied can be expanded.

[0025] Furthermore, the planned route generation process further includes a control point adjustment process for adjusting the control points that have been set to change the curved planned route. When the planned route is generated based on the adjusted control points, it is possible to flexibly adjust and generate a planned route that reflects, for example, the avoidance of obstacles and the adjustment of the approach angle upon arrival.

[0026] Furthermore, in the process of generating the planned route, if the planned route is divided into multiple segment routes that are intended to switch control modes, a control mode corresponding to the segment route is used, and control can be performed by switching modes according to the segment route, particularly for the planned route leading to the destination point including docking, allowing the ship to be accurately followed to the destination point.

[0027] In addition, if the speed at which the ship will sail along the planned route is calculated during the automatic ship steering calculation process, and the speed control means including the clutch of the automatic ship steering device is controlled based on the calculated speed during the control process, adjusting the speed with the speed control means such as the clutch makes it easier to guide the ship to a destination point, including berthing, for example.

[0028] Furthermore, in the planned route generation process, if a planned route is generated that includes a segmented route in which, when the preset ship speed at the arrival position is zero, the ship's approach angle to the arrival position will be a predetermined angle when the distance between the ship and the arrival position reaches a predetermined distance, a segmented route can be generated in which the ship turns toward the arrival position when the distance to the arrival position reaches the specified distance, and approaches the arrival position at an appropriate approach angle, thereby ensuring the arrival direction.

[0029] Furthermore, in the planned route generation process, when the predetermined vessel speed at the arrival position is zero and the vessel's direction of travel is at a predetermined approach angle to the arrival position, if a planned route is generated that includes an approximately straight segment route for performing speed control so that the vessel's speed becomes zero when the vessel reaches a position where the distance between the vessel and the arrival position is shorter than the predetermined distance, a segment route can be generated that performs speed control and can guide the vessel to the arrival position more reliably and safely.

[0030] In addition, if weather and sea condition information around the ship is obtained during the ship information acquisition process, and the steering angle and speed are corrected during the automatic maneuvering calculation process by taking into account external forces on the ship based on the weather and sea condition information, the ship can be made to follow the planned route more accurately using the corrected steering angle and speed that take into account the external forces.

[0031] Furthermore, if the external forces on the ship due to wind direction and wind speed obtained from meteorological and oceanographic information are calculated, the ship's hull motion due to the external forces is predicted, and a steering angle or speed is derived that will cancel out the ship's hull motion due to the external forces, and the automatic ship steering device is controlled to compensate for wind disturbances, deviation from the planned route can be kept below a certain level even in strong winds.

[0032] Furthermore, according to the automatic guidance program for a ship of the present invention, by combining control based on pure pursuit calculations (pure pursuit control) with an automatic ship steering device and performing automatic guidance that follows a planned route, it is possible to provide a program that performs control without performing a large amount of calculations and suppresses deviation from the planned route to a certain level even in the presence of external disturbances.

[0033] Furthermore, the automatic guidance system for ships of the present invention combines control based on pure pursuit calculations (pure pursuit control) with an automatic ship steering device to perform automatic guidance that follows the planned route, thereby enabling control without the need for large amounts of calculation, and making it possible to suppress deviation from the planned route to a certain level even in the presence of external disturbances.

[0034] In addition, if the ship's speed is acquired by the ship information acquisition means and the pure pursuit calculation means and automatic ship maneuvering calculation means perform calculations using the speed, the ship can be made to follow the planned route more accurately depending on the speed.

[0035] In addition, when the planned route generation means acquires the arrival position and arrival direction of the input ship's arrival point, and calculates a planned route that can reach the arrival position and ensure the arrival direction using the position, heading direction, and speed acquired by the ship information acquisition means, it is possible to generate a planned route that draws a smooth curve that connects to the arrival position in the direction (angle) of the arrival direction.

[0036] Furthermore, if the planned route generation means acquires sea area information and calculates the planned route by taking into account information on unnavigable sea areas, the safety of the ship's automatic guidance system can be improved and the sea areas to which the ship's automatic guidance system can be applied can be expanded.

[0037] In addition, the planned route generation means has a control point adjustment section in which the crew checks and changes the set control points for changing the curved planned route, or an automatic control point adjustment section that automatically adjusts the control points based on the ship information obtained by the ship information acquisition means, and when generating a planned route based on the adjusted control points, the planned route can be flexibly adjusted to reflect, for example, the avoidance of obstacles or adjustment of the approach angle upon arrival, and can be generated manually or automatically.

[0038] Furthermore, when the planned route generation means divides the planned route into multiple segment routes that switch control modes, the control mode is performed according to the segment route, and the mode is switched according to the segment route, particularly for the planned route leading to the arrival point including docking, so that the ship can be accurately followed to the arrival point.

[0039] In addition, if the automatic ship steering calculation means calculates the speed at which the ship will sail along the planned route and the control means controls the speed control means including the clutch of the automatic ship steering device to obtain the calculated speed, adjusting the speed with the speed control means such as the clutch makes it easier to guide the ship to a destination point, including berthing, for example.

[0040] Furthermore, in the planned route generation means, when the preset ship speed at the arrival position is zero, if a planned route is generated that includes a segmented route in which the ship's approach angle to the arrival position will be a predetermined angle when the distance between the ship and the arrival position reaches a predetermined distance, a segmented route can be generated in which the ship turns toward the arrival position when the distance to the arrival position reaches the specified distance, and approaches the arrival position at an appropriate approach angle, thereby ensuring the arrival orientation.

[0041] Furthermore, when the planned route generation means generates a planned route that includes an approximately straight segment route for controlling the speed of the vessel so that it becomes zero when it reaches a position where the distance between the vessel and the arrival position is shorter than the predetermined distance when the vessel's preset speed at the arrival position is zero and the vessel's direction of travel is at an approach angle to the arrival position that is predetermined, it is possible to generate a segment route that performs speed control and can guide the vessel to the arrival position more reliably and safely.

[0042] In addition, if the ship information acquisition means acquires weather and sea condition information around the ship, and the automatic ship steering calculation means corrects the steering angle and speed by taking into account external forces on the ship based on the weather and sea condition information, the ship can be made to follow the planned route more accurately using the corrected steering angle and speed by taking into account the external forces.

[0043] Furthermore, if the external forces on the ship due to wind direction and wind speed obtained from meteorological and oceanographic information are calculated, the ship's hull motion due to the external forces is predicted, and a steering angle or speed is derived that will cancel out the ship's hull motion due to the external forces, and the automatic ship steering device is controlled to compensate for wind disturbances, deviation from the planned route can be kept below a certain level even in strong winds.

[0044] In addition, if the vessel is equipped with a display means for displaying at least one of the planned route, the vessel's position, the vessel's heading, the target point, or the target point's heading, crew members can check the planned route and monitor the operation status of the automatic guidance system.

[0045] Furthermore, the ship of the present invention can provide a ship equipped with an automatic guidance system that combines pure pursuit control and an automatic ship-steering device, and that can accurately follow a planned route even in the presence of external disturbances. [Brief explanation of the drawings]

[0046] [Figure 1] 1 is a schematic diagram of an automatic guidance system for a ship according to a first embodiment of the present invention; [Figure 2] Flowchart of the automatic guidance method using the ship's automatic guidance system [Figure 3] A diagram showing the Pure Shoot algorithm [Figure 4] Conceptual diagram of tracking performance for the planned route [Figure 5] A diagram showing the tracking performance of the automatic ship steering system when combined with pure pursuit control, evaluated by tracing the ship's wake. [Figure 6] Flowchart of automatic berthing maneuvering using the automatic guidance system [Figure 7] Figure 10 shows an example of the generated docking path and control mode. [Figure 8] Diagram showing the coordinate system for berthing maneuvers [Figure 9] Schematic diagram of the docking path using the same Bezier curve [Figure 10]A flowchart showing the details of the control process for automatic berthing maneuvering [Figure 11] Diagram showing the coordinate system for the vessel's motion [Figure 12] A comparison diagram of the Hybrid-state A* search method according to the second embodiment of the present invention with the classical A* algorithm. [Figure 13] FIG. 10 is a diagram showing path tracking control using a pure pursuit algorithm in a third embodiment of the present invention. [Figure 14] A diagram showing disruption of path-following control due to wind [Figure 15] Figure showing the analysis results [Figure 16] FIG. 10 is a diagram showing the wind pressure coefficient of the experimental ship in Example 1. [Figure 17] FIG. 1 is a configuration diagram of a hull control system according to a first embodiment of the present invention. [Figure 18] Figure showing a comparison of the measured results of the same turning test with the adjustment / simulation results [Figure 19] Figure showing the experimental results of automatic berthing maneuvering at the virtual pier [Figure 20] FIG. 10 shows the measurement values ​​acquired by the vessel information acquisition means in the experiment on automatic berthing maneuvering at the virtual pier. [Figure 21] Figure showing the results of the automatic berthing experiment at the actual pier [Figure 22] Figure 10 shows the measurement values ​​acquired by the vessel information acquisition means in the experiment on automatic berthing maneuvering at the actual pier. [Figure 23] Figure showing the experimental results of automatic berthing maneuvering at a virtual pier under strong winds [Figure 24] Figure 1 shows the measurement values ​​acquired by the vessel information acquisition means in the experiment on automatic berthing maneuvering at the virtual pier under strong winds. [Figure 25] FIG. 10 is a diagram showing a planned route to berthing generated using Hybrid-state A* according to a second embodiment of the present invention. [Figure 26] A diagram showing an example of calculating the docking path using the point cloud measured by the LiDAR. [Figure 27] A diagram showing an example of calculating a route by intentionally changing the ship's position from the position measured by the LiDAR. [Figure 28] FIG. 10 shows the results of an actual ship test of pure pursuit with feedback control and berthing control by HCS according to the third embodiment of the present invention. [Figure 29] 29 shows the actual measurement values ​​of the state shown in FIG. 28. [Figure 30] Figure showing the results of actual ship tests of pure pursuit with feedback control and berthing control by HCS under the same strong winds. [Figure 31] 30 shows the actual measurement values ​​of the state shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0047] An automatic ship guidance method, an automatic ship guidance program, an automatic ship guidance system, and a ship according to a first embodiment of the present invention will be described below.

[0048] Figure 1 is a schematic diagram of an automatic guidance system for ships. The automatic guidance system for a ship comprises a planned route generation means 10 that acquires or calculates a planned route, a ship information acquisition means 20 that acquires the position and heading of the ship, a pure pursuit calculation means 30 that calculates a target point that satisfies specified conditions on the planned route in the ship's direction of travel based on the position and heading of the ship, or calculates the heading of the target point, an automatic ship steering calculation means 40 that calculates the ship's steering angle based on the target point or the heading of the target point, a control means 50 that controls an automatic ship steering device 60 based on the ship's steering angle, a speed control means 61 for the clutch etc. of the automatic ship steering device 60, and a display means 70 such as a screen. The automatic ship steering device 60 can include actuators such as a rudder for steering and a clutch for controlling speed, or it can include only control function parts such as a rudder and a clutch, or it can include only the function of issuing command values ​​for controlling the rudder and clutch, or it can use these in combination with a rudder, a clutch, etc.

[0049] FIG. 2 is a flowchart of an automatic guidance method using an automatic guidance system for ships, and FIG. 3 is a diagram showing the Pure Chute algorithm. First, the planned route generation means 10 generates a planned route for the ship (planned route generation process S1). The generated planned route is input to the pure pursuit calculation means 30 and the automatic ship maneuvering calculation means 40. The planned route generation means 10 can generate a planned route automatically, or can generate a planned route by receiving input of a preset planned route. The generation of the planned route will be described in detail later. After the planned route generation process S1, the control means 50 starts maneuvering the ship based on the acquired planned route (maneuvering start process S2). The vessel information acquisition means 20 is, for example, a position sensor or an azimuth angle sensor, and acquires the position and heading of the vessel (vessel information acquisition step S3).

[0050] The pure pursuit calculation means 30 calculates a target point that satisfies predetermined conditions on the planned route in the direction of travel of the ship, or calculates the direction of the target point, based on the position and heading of the ship (pure pursuit calculation process S4). Pure pursuit is a path-following control algorithm that is widely used in fields such as robotics and autonomous driving. Pure pursuit performs turning control to reach a target point on a pre-set directed path, as shown in Figure 3, a point on the path a certain distance ahead from the installation position of a position sensor such as a GNSS sensor mounted on a ship. The distance to this target point is called the look ahead distance. When determining the target point (look-ahead distance), find the maximum radius of curvature of the expected route curve when following the route, prepare a circular route with this radius of curvature, and set the look-ahead distance so that the circular route can be followed. Note that it is also possible to check whether or not the route can be followed by conducting an actual ship test, and if maneuverability indexes such as KT are known, it can also be determined from a simple simulation. In the pure pursuit calculation process S4, the pure pursuit calculation means 30 calculates a target point, for example, at a predetermined distance on the planned route in the direction of travel, based on the planned route generated by the planned route generation means 10 in the planned route generation process S1, or calculates the orientation of the target point, and sends, for example, the calculated orientation to the automatic ship maneuvering calculation means 40. In addition, the pure pursuit calculation means 30 successively updates the orientation of the target point (updates the set value) as the ship navigates.

[0051] The automatic ship-steering calculation means 40 calculates the steering angle of the ship based on the target point or the direction of the target point and the position or heading of the ship (automatic ship-steering calculation step S5). The control means 50 controls the automatic ship-steering device 60, which automatically controls the steering, based on the steering angle of the ship calculated by the automatic ship-steering calculation means 40 (control step S6). As a result, a ship track along the planned route is obtained. The automatic ship steering device 60 is linked to a gyro or the like, and when a set value for heading or the like is set, it controls the steering device by PID control or adaptive control so that the set heading or the like is obtained. After the control step S6, the control means 50 determines whether or not a control end signal has been received (control end determination step S7). The control end signal is input automatically or manually by a crew member, for example, when the ship approaches the destination within a predetermined distance. If the control means 50 determines in the control end determination process S7 that it has received a control end signal, it ends control of the automatic ship steering device 60. On the other hand, if it determines in the control end determination process S7 that it has not received a control end signal, it returns to the ship information acquisition process S3 and continues control.

[0052] Figure 4 is a conceptual diagram of tracking performance for a planned route, with Figure 4(a) showing tracking performance when only automatic steering by the automatic steering system is used, and Figure 4(b) showing tracking performance when control is performed that combines automatic steering by the automatic steering system and pure pursuit (simple pursuit). Figure 5 is a diagram evaluating tracking performance when control is performed that combines automatic steering by the automatic steering system and pure pursuit, using track tracing. Figure 5(a) shows the results of tracking a planned route using control that combines automatic steering by the automatic steering system and pure pursuit, and Figure 5(b) shows the results of tracking a planned route with a constant rudder angle (+15°). As shown in Figure 4(a), existing automatic steering (autopilot) using a heading gyroscope only controls the ship's heading, so it will deviate from its course when affected by wind or currents. On the other hand, as shown in Figures 4(b) and 5(a), by combining control based on pure pursuit calculations (pure pursuit control) with automatic steering to perform automatic guidance that follows a planned route, control can be performed without requiring a large amount of calculation as in model predictive control, and even if there is a disturbance, deviation from the planned route can be suppressed to a certain level or less, and automatic control can be performed along the route. In particular, pure pursuit control makes it easy to follow a planned route that has curved sections when combined with an automatic ship steering device 60 such as an autopilot. In this way, control combining pure pursuit and automatic steering includes control that compensates for disturbances compared to automatic steering alone, making it possible to suppress deviation from the path to a certain level. Furthermore, the computational load is light because it only calculates the steering amount relative to a target point on the path. Furthermore, the only parameter required for control is essentially a single parameter: the look-ahead distance. Furthermore, as long as the path curvature is small and there is a certain level of forward speed, the stability of the system can be discussed in terms of the stability of the automatic steering. In other words, classical stability analysis can be used to design stable control parameters, and basic stability can be guaranteed based on the control stability of the automatic steering.

[0053] Next, an automatic guidance method for guiding a ship to a destination point will be described. In this embodiment, the destination point is a pier. Figure 6 is a flowchart of automatic berthing maneuvering using an automatic guidance system. When the automatic docking control is started, the vessel information acquisition means 20 acquires the position (latitude and longitude) of the vessel, the heading direction, and the vessel speed (first vessel information acquisition step S11). After the first ship information acquisition process S11, the crew or the like inputs the docking position coordinates and the azimuth angle at docking into the automatic guidance system (docking information input process S12). After the docking information input process S12, the control means 50 starts maneuvering the ship (maneuvering start process S13).

[0054] After the ship maneuvering start process S13, the planned route generation means 10 acquires the input arrival position (docking position coordinates) and arrival orientation (docking orientation angle) of the ship's arrival point, and uses the ship's position, heading, and speed acquired in the first ship information acquisition process S11 to calculate a curve connecting to the arrival point taking into account the arrival position and arrival orientation as the planned route, thereby generating a planned route that can reach the arrival position and ensure the ship's arrival orientation (planned route generation process S14).This makes it possible to generate a planned route (docking route) that draws a smooth curve connecting to the arrival position in the direction (angle) of the arrival orientation. Here, FIG. 7 is a diagram showing an example of the generated docking path and control mode, and FIG. 8 is a diagram showing a coordinate system for docking maneuvering. Assuming that the control mode of the control means 50 will be switched on the planned route up to docking, the planned route generation means 10 divides the planned route into a plurality of segmented routes. In this embodiment, as shown in FIG. 7 , the planned route generation means 10 divides the docking route indicated by the dashed line into four route segments: a first route segment 1A controlled in the route-following mode, a second route segment 1B controlled in the neutral navigation mode, a third route segment 1C controlled in the heading mode, and a fourth route segment 1D controlled in the stop mode. The control means 50 switches the control mode for each route segment. This switching is based, for example, on the procedure used by the ship operator when maneuvering the ship to dock. Furthermore, in this embodiment, to reduce excessive load on the main engine, deceleration by propeller reversal is not performed except in the final stop mode, and deceleration is performed in neutral. For this reason, the control mode switching positions are determined for each ship, taking into account the navigation distance required for sufficient deceleration in each section, and are set at positions, for example, 10, 70, and 100 m along the route from the docking position to ensure the distance required for deceleration. In order to facilitate the handling of position information, the latitude and longitude information obtained from the ship information acquisition means 20 is calculated by dividing the docking position by the origin O. berth The coordinate system is an XY plane with the unit of length converted to meters. In this case, the X axis is positive in the north and the Y axis is positive in the east. Furthermore, to clarify the positional relationship with Pier 2, the XY coordinate system is rotated to match the direction of Pier 2, and the x berth -y berth Use a coordinate system (the origin is the same as O berth ) Figure 8 shows the relationship between these two coordinate systems. In Figure 8, α berth corresponds to the azimuth angle of Pier 2.

[0055] Figure 9 is a schematic diagram of the docking path using Bezier curves. From actual examples of ship maneuvering, it is considered that the docking path for a port and starboard ship should be a smooth curve that extends from the ship's position at the start of maneuvering in the direction of the bow and connects to the docking position at an angle parallel to pier 2. This shape can be expressed by a cubic Bezier curve. In general, an N-1 degree Bezier curve is formed by N control points B0...B N-1 It is an N-1 degree curve defined by using t as a parameter and is expressed as the following equations (1) and (2).

number

number

[0056] If the arrival point is Pier 2, the speed of the vessel at the arrival position is preset as zero. In the planned route generation step S14, the planned route generation means 10 generates a planned route including a segmented route in which the approach angle of the ship to the arrival position is a predetermined angle when the distance from the ship to the arrival position reaches a predetermined distance. This makes it possible to generate a segmented route in which the ship turns toward the arrival position when the distance to the arrival position reaches the predetermined distance, and approaches the arrival position at an appropriate approach angle to ensure the arrival orientation. In this embodiment, this corresponds to the third segmented route 1C controlled in the turning mode. Furthermore, the planned route generation means 10 generates a planned route including a substantially straight segmented route for controlling the speed of the vessel so that it becomes zero when the vessel reaches a position where the distance between the vessel and the arrival position is shorter than a predetermined distance when the vessel's preset speed at the arrival position is zero and the vessel's traveling direction is at a predetermined approach angle to the arrival position. This allows for the generation of a segmented route that can perform speed control and guide the vessel to the arrival position more reliably and safely. In this embodiment, this corresponds to the fourth segmented route 1D controlled in stop mode. Note that the "predetermined distance" in the case of docking is, for example, the distance that allows for the exchange of mooring ropes. The "predetermined approach angle to the arrival position" may have a certain degree of flexibility.

[0057] The planned route generation means 10 may also be provided with at least one of a control point adjustment unit in which the crew member checks and changes the control points set for the planned route, or an automatic control point adjustment unit that automatically adjusts the control points based on the ship information obtained by the ship information acquisition means 20. In this case, the planned route generation process S14 further includes a control point adjustment process in which the set control points B1 to B4 are adjusted to change the curved planned route, and the planned route is generated based on the adjusted control points. This allows for the generation of a planned route that reflects, for example, avoidance of obstacles such as other ships and shallow waters, and adjustment of approach angles upon arrival, and can be flexibly adjusted manually or automatically. When a crew member makes a change, the crew member adjusts the control point by giving instructions to the control point adjustment unit while looking at the screen using a touch panel or trackball. When the automatic control point adjustment unit makes a change, it automatically adjusts the planned route based on nautical chart information and sensor information such as LiDAR (light detection and ranging). For example, if two-dimensional information about an obstacle is obtained from a nautical chart or sensor information and the planned route overlaps the obstacle, the length between control points B1 and B2 or B3 and B4 is changed in 0.1-meter increments to find a route where the planned route does not overlap the obstacle. The calculation can be performed by brute force, or a solution can be found efficiently using dynamic programming. If a solution cannot be found, a warning is issued by display or audio, prompting the crew to make changes using the control point adjustment unit. The control points may be manually or automatically adjusted when the planned route is first generated, or after the generated planned route has been confirmed, the control points may be corrected and adjusted, and the route may be generated again.

[0058] Returning to FIG. 6, after the planned route generation process S14, the vessel information acquisition means 20 acquires the position, heading, and speed of the vessel (second vessel information acquisition process S15). The control means 50 controls the automatic ship steering device 60 based on the position, heading, and speed of the ship acquired in the second ship information acquisition process S15 (control process S16). After the control step S16, the control means 50 determines whether or not the ship has reached the docking position (docking determination step S17). If the control means 50 determines "NO" in the docking determination process S17, i.e., that the ship is not docked, it returns to the second ship information acquisition process S15 and continues control. On the other hand, if the control means 50 determines "YES" in the docking determination process S17, i.e., that the ship is docked, it ends the automatic docking control.

[0059] Figure 10 is a flowchart showing the details of the control process S16 in automatic berthing maneuvering, and Figure 11 is a diagram showing the coordinate system for ship motion. In Figure 11, in the space-fixed coordinate system o0-x0y0z0, x0 is set to north and y0 is set to east. Furthermore, the origin o of the ship-fixed coordinate system is set at the midship position of the ship. The pure pursuit calculation means 30 calculates a target point that satisfies specified conditions on the planned route in the direction of travel of the ship, or calculates the direction of the target point, based on the position, heading, and speed of the ship acquired by the ship information acquisition means 20 in the second ship information acquisition process S15 (pure pursuit calculation process S21). When Pure Pursuit is applied to a ship, it is necessary to follow the target azimuth angle by steering, so a Heading Control System (HCS) with PD control for the target azimuth angle is combined. In this case, if the relative azimuth angle from the ship (own ship) to the target point is α, the command rudder angle by the HCS with PD control for the bow azimuth angle can be calculated as shown in equation (3) below, with a maximum of ±45°.

number

[0060] After the pure pursuit calculation step S21, the automatic ship-steering calculation means 40 calculates the steering angle of the ship based on the target point or the direction of the target point, the position or heading of the ship, and the speed (automatic ship-steering calculation step S22). In this way, by acquiring the ship's speed in the second ship information acquisition process S15 and performing calculations using the speed in the pure pursuit calculation process S21 and the automatic maneuvering calculation process S22, the ship can be made to follow the planned route with high accuracy according to the speed. The control means 50 controls and steers the automatic ship steering device 60 based on the ship's steering angle (commanded rudder angle) calculated by the automatic ship steering calculation means 40. Steering includes operations to control the ship's heading, such as operating the bow thruster. By combining pure pursuit and automatic steering and having the control means 50 control the ship's position, the ship can accurately follow the docking path.

[0061] The control means 50 controls the speed control means 61 including the clutch so as to obtain the speed (ship speed) set as a target value for each control section by calculation by the automatic ship-maneuvering calculation means 40 in the four control sections 1A to 1D shown in FIG. 7. The speed control means 61 includes a clutch and propeller speed control based on engine telegraph operation (main engine load). In this embodiment, however, in consideration of the mechanical load on the main engine and the safety of the ship, the main engine speed is fixed at idling speed during berthing maneuvering. The bow thruster is also not operated. Therefore, speed control is possible only by switching the clutch. The clutch can be in three states: forward, neutral, and astern.

[0062] Based on the information acquired by the ship information acquisition means 20, the control means 50 calculates the linear distance D from the position sensor of the ship information acquisition means 20 mounted on the ship to the docking position (pier 2). berth is greater than a first distance D1, which is the straight-line distance from the docking position to the boundary position (control mode switching position) between the first segmented route 1A and the second segmented route 1B (first distance determination step S24). The control means 50 determines "YES" in the first distance determination step S24, i.e., the distance D berth If it is determined that the first distance D1 is greater than the first distance D2, the control is performed in the path following mode. In the path following mode, the clutch is always set to forward.

[0063] On the other hand, the control means 50 determines "NO" in the first distance determination step S24, i.e., the distance D berth If it is determined that the distance is equal to or less than the first distance D1, the distance to the berthing position D berth is greater than a second distance D2, which is the straight-line distance to the boundary position (control mode switching position) between the second segment route 1B and the third segment route 1C (second distance determination step S25). The control means 50 determines "YES" in the second distance determination step S25, i.e., the distance D berth If it is determined that the longitudinal speed u is greater than the second distance D2, the control means 50 performs control in the neutral navigation mode. In the neutral navigation mode, the control means 50 determines whether the longitudinal speed u is greater than a predetermined speed u1 (first speed determination step S26). The predetermined speed u1 is set to, for example, 1.0 [m / s]. If the control means 50 determines "YES" in the first speed determination process S26, i.e., that the longitudinal speed u is greater than the predetermined speed u1, the control means 50 puts the clutch in neutral. On the other hand, if the control means 50 determines "NO" in the first speed determination process S26, i.e., that the longitudinal speed u is equal to or less than the predetermined speed u1, the control means 50 puts the clutch in forward motion. In this way, the state of the clutch in the neutral navigation mode is basically neutral, and when the longitudinal speed u drops below a predetermined speed u1 due to a strong headwind or the like, the clutch is switched to forward.

[0064] The control means 50 determines "NO" in the second distance determination step S25, i.e., the distance D berth If it is determined that the distance is equal to or less than the second distance D2, the distance to the berthing position D berth is greater than a third distance D3, which is the straight-line distance to the boundary position (control mode switching position) between the third segment route 1C and the fourth segment route 1D (third distance determination step S27). The control means 50 determines "YES" in the third distance determination step S27, i.e., the distance D berth If it is determined that the third distance D3 is greater than the third distance D4, the control is performed in the stem turning mode. In the stem turning mode, the control means 50 determines whether the longitudinal velocity u is greater than a predetermined velocity u2 (second velocity determination step S28). The predetermined velocity u2 is set to, for example, 1.0 [m / s]. If the control means 50 determines "YES" in the second speed determination process S28, that is, that the longitudinal speed u is greater than the predetermined speed u2, the control means 50 puts the clutch in neutral. On the other hand, if the control means 50 determines "NO" in the second speed determination process S28, that is, that the longitudinal speed u is equal to or less than the predetermined speed u2, the control means 50 determines whether or not the target azimuth angle α is α-ψ<0[deg] when attached to starboard, and whether or not the target azimuth angle α is α-ψ<0[deg] when attached to port (target azimuth angle determination process S29). If the control means 50 determines "YES" in the target azimuth angle determination process S29, that is, if it determines that α-ψ<0 [deg] (when attached to the starboard side) or α-ψ<0 [deg] (when attached to the port side) with respect to the target azimuth angle α, the clutch is moved forward. On the other hand, when the control means 50 judges "NO" in the target azimuth angle judgment step S29, that is, when it judges that the target azimuth angle α is not α-ψ<0 [deg] (when attached to the starboard side) or α-ψ<0 [deg] (when attached to the port side), the control means 50 judges that the distance D to the berthing position is not berth is the specified distance D F It is determined whether or not the distance is greater than the predetermined distance (for example, 50 m) and whether or not |α-ψ|>5 [deg] (distance and angle determination step S30). The control means 50 determines whether the distance and angle determination step S30 is "YES," i.e., whether the distance D berth is the specified distance D F If it is determined that the angle is greater than |α-ψ| and |α-ψ|>5[deg], the clutch is moved forward. On the other hand, if the result of the distance / angle determination step S30 is "NO", that is, if the distance D berth is the specified distance D F If it is determined that the longitudinal velocity u is equal to or less than 5 degrees, or if it is determined that |α-ψ| is not greater than 5 degrees, it is determined whether the longitudinal velocity u is smaller than a predetermined velocity u3 (third velocity determination step S31). The predetermined velocity u3 is set to, for example, 0.3 m / s. If the control means 50 determines "YES" in the third speed determination process S31, i.e., that the longitudinal speed u is smaller than the predetermined speed u3, the control means 50 puts the clutch in forward motion. On the other hand, if the control means 50 determines "NO" in the third speed determination process S31, i.e., that the longitudinal speed u is equal to or greater than the predetermined speed u3, the control means 50 puts the clutch in neutral. In this way, the clutch state in the turning mode is basically neutral, and is switched to forward when a predetermined condition is met. If a stop mode is scheduled to follow the turning mode, it is preferable to reduce the speed to a predetermined speed during the turning mode.

[0065] The control means 50 determines "NO" in the third distance determination step S27, i.e., the distance D berth When it is determined that the distance x to the docking position is equal to or less than the third distance D3, the control unit 50 controls the boat in the stop mode. berthis greater than a predetermined distance x1 and the longitudinal speed u is greater than a predetermined speed (for example, 0.5 [m / s]) (first distance / speed determination step S32). The control means 50 determines "YES" in the first distance / speed determination step S32, i.e., the distance x berth is greater than the predetermined distance x1 and the forward / rearward speed u is greater than the predetermined speed, the clutch is put into reverse. On the other hand, the control means 50 determines "NO" in the first distance / speed determination step S32, i.e., the distance x berth is smaller than the predetermined distance x1, or if it is determined that the longitudinal speed u is equal to or less than the predetermined speed, the distance x to the berthing position berth is greater than a predetermined distance x2 and the longitudinal speed u is greater than a predetermined speed (for example, 0.1 [m / s]) (second distance / speed determination step S33). The control means 50 determines "YES" in the second distance / speed determination step S33, i.e., the distance x berth is greater than the predetermined distance x2 and the forward / rearward speed u is greater than the predetermined speed, the clutch is put into reverse. On the other hand, the control means 50 determines "NO" in the second distance / speed determination step S33, i.e., the distance x berth If it is determined that the distance x2 is less than the predetermined distance, or the longitudinal speed u is less than the predetermined speed, the distance x to the berthing position is berth It is determined whether or not is smaller than 0 and whether or not the longitudinal velocity u is smaller than 0 [m / s] (third distance / velocity determination step S34). The control means 50 determines "YES" in the third distance / speed determination step S34, i.e., the distance x berth If it is determined that is smaller than 0 and the forward / rearward velocity u is smaller than 0 [m / s], the clutch is set to forward. On the other hand, the control means 50 determines "NO" in the third distance / speed determination step S34, i.e., the distance x berth If it is determined that is 0 or greater, or the longitudinal speed u is 0 [m / s] or greater, the clutch is put into neutral. In this way, in the final stop mode, the clutch is gradually put in reverse until the forward / reverse direction speed u becomes, for example, 0.1 [m / s] or less. berth If u<-0.0[m] and u<0[m / s], put the clutch in forward. If these conditions are not met, put the clutch in neutral.

[0066] By using a control mode that corresponds to the segmented route in this way, it is possible to switch the mode and control the ship according to the segmented route, particularly for a planned route leading to a destination point including docking, and to accurately follow the ship to the destination point. Furthermore, by calculating the speed at which the ship will navigate the planned route in the automatic ship-steering calculation process S22 and controlling the speed control means 61 including the clutch of the automatic ship-steering device 60 based on the calculated speed, the speed can be adjusted by the speed control means 61 such as a clutch, making it possible to easily guide the ship to a destination point, including berthing, for example. In particular, except for the stop mode of the fourth route segment 1D, it is preferable to limit astern operation of the clutch to prevent excessive load on the main engine and to basically decelerate through neutral navigation, and in the heading mode of the third route segment 1C, it is preferable not to make a sharp turn by applying the propeller wake to the rudder unless the ship speed is sufficiently small, even if the difference between the target azimuth angle and the bow azimuth angle becomes large. Furthermore, the ship's automatic guidance system separates ship speed and position control during berthing maneuvers, and sets and follows a route to the berthing position. By performing berthing maneuvers using this path tracking, crew members can confirm the planned route (berthing route) in advance, and by checking deviations from the route, can confirm whether the automatic control is working properly. The berthing route and deviations from the route are displayed on the display means 70. The display means 70 also displays the ship's position, bow direction, target point, target point direction, ship speed, meteorological and sea condition information, calculated external forces, etc. In addition, by using path-following control that can set the angle when approaching pier 2 depending on the path, the design can separate the issues of path planning and control stability.

[0067] Furthermore, the ship information acquisition means 20 can acquire information on meteorological and oceanographic conditions around the ship in the second ship information acquisition process S15, and the automatic ship maneuvering calculation means 40 can correct the steering angle and speed by taking into account external forces on the ship based on the meteorological and oceanographic information in the automatic ship maneuvering calculation process S22. The steering angle and speed corrected by taking into account external forces can cause the ship to follow the planned route with greater accuracy. When measuring external forces, it is difficult to make precise measurements when the ship is changing course, accelerating, decelerating, etc., so it is preferable to measure while the ship is traveling straight at a constant speed, such as in neutral navigation mode, and use the results to correct the steering angle and speed.

[0068] In this way, automatic guidance that follows a planned route by combining pure pursuit with the automatic ship steering device 60 is particularly effective when performing fine control along a curved planned route, such as when docking. While the above mainly describes a method and system for automatic guidance of a ship, the present invention can also be an automatic guidance program for a ship that uses an automatic ship steering device 60 that automatically controls at least the steering of a sailing ship, and that causes a computer to execute planned route generation processes S1, S14 in accordance with input conditions, ship information acquisition processes S3, S11, S15, pure pursuit calculation processes S4, S21, automatic ship maneuvering calculation processes S5, S22, and control processes S6, S16. In this way, by combining pure pursuit and the automatic ship steering device 60 and performing automatic guidance that follows the planned route, it is possible to provide a program that suppresses deviation from the planned route to a certain level even in the presence of disturbances, without requiring a large amount of calculation as with model predictive control.

[0069] Next, a second embodiment of the present invention will be described, which relates to a method for automatically guiding a ship, a program for automatically guiding a ship, a system for automatically guiding a ship, and a ship. The same functional components as those in the above-described embodiment will be designated by the same reference numerals, and their description will be omitted. In the first embodiment described above, the planned route (docking route) was generated using a route planning algorithm that uses Bezier curves. However, this algorithm geometrically calculates the route from the ship position and the docking target point without taking into account the navigation environment, such as the surrounding topography or shallow waters around the pier 2, so depending on the initial position of the ship, it is possible that the route generated will be difficult to navigate in actual practice. Therefore, in this embodiment, sea area information is acquired in the planned route generation steps S1 and S14, and the planned route is calculated by the planned route generation means 10 taking into account information about unnavigable sea areas. "Information about unnavigable sea areas" refers to information about sea areas that are unnavigable due to the presence of obstacles such as moving objects or floating objects, or shallow waters, such as ships. This improves the safety of automatic guidance of ships and also expands the sea areas to which automatic guidance of ships can be applied. The acquired sea area information comes from electronic nautical charts that can be used offline, and from information detected in the actual sea area while sailing using sensors such as LiDAR. The sea area information detected in the actual sea area while sailing is new information known on the spot, and the planned route generation means 10 can recalculate the planned route based on this new information.

[0070] In this embodiment, a planned route appropriate for berthing control that takes into account the navigation environment is generated using the Hybrid-state A* algorithm, which is one of the route search algorithms. The Hybrid-state A* algorithm (also known as Hybrid A*) is a path-finding algorithm based on the classic algorithm known as A*. A* first divides the search area into a grid and searches for a path to the goal. A* is classified as a graph search algorithm, and begins with a start node representing the initial position, then sequentially examines the nodes corresponding to the neighboring grids (not occupied by obstacles) until it finally finds a path to the goal node. During the search, the cost of each node is calculated. When searching for the shortest path from the start to the goal, the cost of each node corresponds to the distance traveled to that node and the value of a heuristic function that is defined separately. A common heuristic function is a simple one that returns the distance to the goal. The A* algorithm finds the desired path to the goal by searching for nodes in the direction that minimizes this cost.

[0071] Hybrid-state A* has three innovative features. The first innovation is the use of a four-dimensional search space (x, y, θ, r) for the search. Here, x and y are the original position coordinates, θ is the direction of the moving object (corresponding to the bow direction in the case of a ship), and r is the direction of movement relative to the path, expressed as a binary value of 0 (forward) or 1 (reverse). By shifting the search from the original two-dimensional plane to a four-dimensional space, Hybrid-state A*'s search can continuously search the two-dimensional space, and the resulting trajectory is represented as a continuous curve rather than the broken line connecting the grid centers obtained with A*. Figure 12 compares the search method of Hybrid-state A* with the classical A* algorithm. Figure 12(a) shows the discrete states of the classical A* algorithm, and Figure 12(b) shows the continuous states of the Hybrid-state A* algorithm. The second innovation is to use a cost map using dynamic programming as a heuristic function to reduce the calculation time that increases with the number of dimensions to be searched and to perform searches more efficiently. This makes it possible to efficiently search for a path to the goal even on complex terrain. Furthermore, even when searching in four-dimensional space, the search for each node is carried out in a discretized action space, so it is impossible to reach the goal posture defined in the actual continuous space as is. Therefore, the third innovation is to introduce a method called Analytic Expansion. Analytic Expansion solves the terminal state problem by expanding the path obtained by searching for nodes so that it connects the intermediate path to the goal with a curve. This path expansion usually uses a path generation algorithm called the Reeds-Shepp path. The Reeds-Shepp path is an algorithm that generates the shortest path consisting of arcs and straight lines with a defined direction of travel, given the positions and orientations of two given points. The candidate routes obtained through the steps up to this point are subjected to collision detection to determine whether they are valid routes. If they are within the area, a calculation is made to determine whether an obstacle point is included in the rectangular area that represents the shape of the moving object, and a collision is determined. This process is repeated until a valid route without collisions is found, and the process ends.

[0072] In the first embodiment described above, as shown in Figure 9, the positions of four control points B1, B2, B3, and B4 are designed with reference to the wake of a ship when maneuvering it to dock. Particularly important in generating this route is the curvature of the route up to a distance of approximately 50 m from the pier. In this section, the ship's approach angle with respect to the pier 2 must be kept at around 20 degrees while avoiding nearby shallow waters. Furthermore, the curvature is also limited to a certain extent, taking into account the ship's turning performance and the characteristics of the path-following control. Furthermore, as the distance to the pier 2 becomes closer, the propeller speed must be reduced, and azimuth angle control is required in a situation where steering effectiveness is reduced. For this reason, when applying searches using the Hybrid-state A* algorithm to berthing maneuvers, it is necessary to limit the curvature of the path, just as with Bezier curve paths, and create a berthing path with an appropriate approach angle. When planning a path using Hybrid-state A*, the path near Pier 2 generally has fewer obstacles, so there is a high possibility that the path will be extended using a Reeds-Shepp path. Therefore, by limiting the curvature of the Reeds-Shepp, it is possible to generate a path with an appropriate approach angle. While it is possible to expand this path using a path planning algorithm based on Bézier curves, the Reeds-Shepp algorithm, which is composed of arcs and straight lines, offers an advantage in terms of subsequent path-following control. A Bézier curve path generally has a continuously changing, non-constant curvature. In contrast, a Reeds-Shepp path, composed of arcs and straight lines, has a constant curvature for each section. A constant path curvature ensures a constant target heading (straight line) or a constant difference in heading (arc) in path-following control, including pure pursuit. In the case of a ship, considering the use of an autopilot to control the heading, a constant target value is desirable from a control perspective. If the target value moves, delays in target-following control accumulate, potentially degrading control accuracy. Furthermore, pure pursuit was originally designed with the assumption that the path curvature would be constant. Therefore, a Reeds-Shepp path generated with an appropriate curvature is advantageous for tracking control. On the other hand, the Reeds-Shepp path also defines the direction of travel of the route, which means that a route that needs to be followed in reverse may be generated.If it is necessary to generate a route that does not require reversing when docking, it is possible to suppress the generation of a reverse route by replacing it with a Dubins path consisting of routes in the forward direction only, or by imposing a larger cost on the reverse-forward route compared to other costs, such as a cost map, when calculating the Reeds-Shepp path.

[0073] Next, a third embodiment of the present invention will be described, in which the same functional components as those in the above-described embodiment are designated by the same reference numerals and will not be described again. The path tracking control that combines Pure Pursuit and a Heading Control System (HCS) described in the first embodiment can reduce path deviation at wind speeds of less than about 3 m / s. However, as wind speeds increase, the influence of wind disturbances becomes greater and it may become impossible to reduce the path deviation. In order to expand the operational design domain (ODD) of automatic guidance for ships, a control system that can compensate for path deviation even in situations where the wind speed is high is required. Furthermore, considering application to general ships, it is preferable to minimize the number of parameters required to design a control system. Therefore, the automatic ship guidance system of this embodiment calculates the external force (wind pressure) on the ship due to wind direction and wind speed acquired as meteorological and oceanographic information by the ship information acquisition means 20, predicts the ship motion due to the external force, and controls the automatic ship steering device 60 to derive a steering angle or speed that will cancel out the ship motion due to the external force and compensate for the disturbance caused by the wind. This makes it possible to keep deviation from the planned course below a certain level even in strong winds. It should be noted that the "steering angle or speed that cancels out the hull motion due to an external force" refers to a steering angle or speed that prevents the predicted hull motion from occurring before that motion actually occurs.

[0074] Figure 13 shows the path tracking control using the pure pursuit algorithm. As shown in Figure 13, pure pursuit performs tracking control by controlling the heading so that the ship aims for a target point a little further down the path. The heading control is handled by the HCS (Heading Control System) using PD control. The advantage of this control is that there are few control parameters, and especially with pure pursuit, the distance L from the ship's position to the target point is T The design can be achieved by simply adjusting the following. The boat speed is controlled by switching the clutch. In this embodiment, the ship speed control is further adjusted to improve docking performance in strong winds. In the stem turning mode, the ship is basically in neutral, and the clutch is switched to forward only when the following conditions are met: A) When α-ψ<0[deg]<0 and the longitudinal velocity u is 1.0[m / s] or less, relative to the target azimuth angle α. B) When α-ψ<0[deg]<0 for the target azimuth angle α and the distance along the route to the docking point is 25[m] or more. C) When the forward / backward velocity u is 0.3 [m / s]. This improves steering effectiveness in the turning mode, which requires high control accuracy, and stabilizes heading control.

[0075] Figure 14 shows how wind disturbances affect path-following control. Figure 14 shows how wind disturbances affect path-following control, resulting in deviations from the planned path. When the ship is hit by wind from the side, the deviation from the planned path increases. Unlike automobiles, which have wheels that touch the ground, ships that float on water are particularly susceptible to problems such as lateral sliding and deviation of the ship's heading due to crosswinds. Reducing the path deviation caused by wind can improve the accuracy of path following control.

[0076] In many pure pursuit systems for automobiles, changes in resistance due to headwinds and tailwinds are taken into consideration. In contrast, in the case of a ship, the ship is continuously subjected to external forces from crosswinds, resulting in a control system with a slow response time that gradually changes the ship's path, making feedforward control effective. Therefore, in this embodiment, a method is used in which a feedforward control mechanism is incorporated into the path tracking control to cancel the external force (wind pressure) and the lateral component of the hull of the steering force generated by steering. In using this method, a mathematical model of maneuvering motion constructed from data from actual ship tests in Example 1, described below, was analyzed for the lateral forces acting on the hull due to steering. The objects of analysis are the motions corresponding to the forward, neutral, and reverse states shown in Table 1 below. u, v, and r are the longitudinal speed, lateral speed, and turning angular velocity at the center of the hull, respectively, and nP is the propeller speed. For forward and neutral, the motion state when the ship is traveling straight ahead at the main engine idling speed is used as the reference. For reverse, the analysis was performed using a state where the ship speed is zero as the reference, because the clutch only engages reverse in stop mode. [Table 1]

[0077] Figure 15 shows the analysis results. Dy is the rudder force acting in the lateral direction of the hull when the rudder is turned. F dy The coefficient is determined so as to satisfy the linear relational expression (4) below, and δ is the steering angle.

number

[0078] Wind pressure can be calculated using the methods described in, for example, the literature "Kitamura F. et al.: Estimation of above water structural parameters and wind loads on ships, Ships and offshore structures, 12-8, 2017," and the literature "Kitamura Fumitoshi, Ueno Michio, Fujiwara Toshifumi: A simple ship wind pressure estimation program, Report of the National Maritime Research Institute, Vol. 9, No. 3, pp. 207-213, 2009." FIG. 16 is a diagram showing the wind pressure coefficient of the experimental ship in Example 1. The wind pressure Y acting in the hull lateral direction is A is the wind pressure coefficient C AY It is calculated using the following formula (5).

number

[0079] The steering amount to cancel the lateral wind pressure is calculated from equations (4) and (5) as Y A =F dy By turning the rudder based on the calculated rudder angle, the lateral component of the wind pressure on the hull can be canceled out, but this is only an estimated value, and there is a possibility that errors may occur in the sensor values ​​or other disturbances such as wind pressure moment in the turning direction and tidal currents. Errors caused by these factors are compensated for together by Pure Pursuit and HCS, which have a feedback mechanism. Therefore, the steering amount δR calculated by the feedforward control unit for wind pressure compensation ff and the steering amount δR calculated from the feedback control unit of the Pure Pursuit and HCS. fb Sum of δR ff +δR fb is the actual steering amount. [Example]

[0080] In order to demonstrate automatic docking using an automatic ship guidance system that employs Pure Pursuit and HCS-based path tracking control in the first embodiment, an actual ship experiment was conducted in the waters around Innoshima Island (Innoshima Marina) in Onomichi City, Hiroshima Prefecture. In the sea area where the experiment was conducted, there was a shallow area near the floating pier, so it was necessary to draw a route for docking that would avoid this. In this experiment, the ship docked with its starboard side to the floating pier and the virtual pier.

[0081] When conducting automatic berthing maneuvering on an actual ship, development was carried out on small vessels that are expected to be more susceptible to external disturbances at low speeds. Furthermore, the target vessel specifications were assumed to be a typical single-propeller, single-rudder vessel, and the experimental vessel "Kanmine" managed by the National Maritime Research Institute was used as the test vessel as it met these conditions. The main specifications of the Kanmine used in the experiment are shown in Table 2 below. [Table 2]

[0082] The test vessel is equipped with a Centimeter-Level Augmentation Service (CLAS) receiver compatible with the Quasi-Zenith Satellite System (QZSS) "Michibiki" for position information, and a satellite compass for azimuth angle sensor, as vessel information acquisition means used for automatic vessel guidance. Other vessel information acquisition means can monitor various data in real time, such as propeller rotation speed, engine rotation speed, estimated main engine load, and wind direction and speed.

[0083] Figure 17 is a configuration diagram of the hull control system. The test vessel is equipped with a PC (control personal computer) and a PLC (Programmable Logic Controller) as control means, and a control system centered on a highly reliable and expandable PLC has been constructed to enable control of the experimental vessel from the PC, allowing the hydraulic steering system and main engine remote control system to be monitored and operated from the PC. The PC can receive information acquired by the ship information acquisition means via the PLC and can operate all of the rudder, main engine governor (corresponding to engine telegraph indications), clutch, and thrusters used in normal berthing maneuvers. The information acquired by the vessel information acquisition means can also be monitored from the display means (touch panel) connected to the PLC. The display means also has a function to output audio information such as the distance from the pier, wind conditions, and current control status from a speaker connected to the display means. Furthermore, during automatic control by PC, the operator can cut off communication from the PC at any time and switch to manual operation, and the system also has an emergency stop mechanism that can be activated from the touch panel as a safety measure.

[0084] When developing a system, if it were possible to check the operation of the actual program on land without connecting it to the actual machine during development, from a safety perspective, it would be possible to verify the presence or absence of defects and performance of the entire control program, including the communication parts other than the algorithm, in advance. Therefore, we created a PLC communication emulator with the function of simulating ship motion. This communication emulator has the function of simulating wind conditions and the function of predicting motion based on a mathematical model of maneuvering motion, and can communicate and control using the same protocol as the serial communication between the PLC and PC used on the actual machine. The wind conditions can be simulated according to normal and Weibull distributions based on wind direction and speed, which are set as average values. Waves and tidal currents were not considered in this study, as their impact on berthing operations is minimal within the bay.

[0085] In designing the algorithm, a mathematical model of maneuvering motion based on the MMG model shown below (6) was used to evaluate the response during low-speed navigation and the influence of disturbances, especially wind.

number

number

[0086] To calculate the hydrodynamic forces on the hull, we used the model in equation (8) below, which requires few coefficients and can express the hydrodynamic forces in the lateral and turning directions when the ship is moving at a large angle at low speed, with reference to the literature, "Y. Yoshimura et al.: UNIFIED MATHEMATICAL MODEL FOR OCEAN AND HARBOUR MANOEUVRING, Proceedings of MARSIM 2009, 2009."

number

[0087] The added mass was determined using the multiple regression equation of the Genryo chart, and the resistance coefficients for forward and reverse movements were determined from the results of speed tests of an actual ship idling and from past tank tests. K used to calculate propeller thrust T The -J curve was obtained based on an approximate formula for estimating the performance of the MAU propeller and a database for estimating the characteristics of the B-Series propeller in the second to fourth quadrants. Regarding the propeller rotation speed, it was assumed that it would be controlled by switching the clutch while the main engine was idling near the docking position, and based on measurements on an actual ship, it was determined that this corresponded to 3.1, 0, and -3.1 [rps] for the clutch in forward, neutral, and reverse positions, respectively, and the time delay for clutch switching was ignored. Furthermore, a model was introduced for calculations when the propeller is reversed, which can handle the unbalanced fluid forces that occur and can take into account the fluid forces of the rudder when the propeller is reversed. In addition, when calculating the thrust with the clutch set to neutral, the propeller rotation speed becomes zero, so the calculation of the forward constant J is omitted and the propeller thrust is calculated as T = X. P / (1-t P ) is zero, and the longitudinal effective inflow velocity to the rudder u R Based on the definition of u R =(1-w R )u. The change in rudder angle δ is the command rudder angle δ * The wind pressure coefficient was determined using a method that can be estimated with a small number of input parameters.

[0088] Figure 18 shows a comparison of the measurement results of the turning test and the adjustment / simulation results. In order to identify the fluid force derivatives, etc., measurements were conducted on the actual ship, with the propeller speed at idle at 3.1 rps, including turning tests at rudder angles of 20 and 40 degrees, and Z tests at ±10 and ±20 degrees. Next, a simulation was performed using equation (6) while referencing various estimation formulas and databases, and the coefficients were adjusted by comparing them with the measured values ​​from the actual ship experiment. The results of the identification using this procedure are shown in Figure 18 and Table 3 below. In Figure 18, the rudder angle is 45 degrees, the average true wind speed is 2.08 [m / s], and the average true wind direction is 348.4 [deg]. There are differences in the wake because the effects of tidal currents, which could not be measured during the adjustment work, were excluded, but it can be seen that the velocity components u, v, and r are able to generally reproduce the motion of the actual ship. [Table 3]

[0089] Using the constructed mathematical model of maneuvering motion, an algorithm was developed and applied to an experimental vessel. The verification of automatic docking by the automatic guidance system using an experimental vessel was carried out under two settings: a "virtual pier" in which the origin of the position coordinates is a point about 30 m away from the floating pier, and a "real pier" in which the actual floating pier is the target. There is no difference in the docking maneuvers under these two conditions other than the target docking point.

[0090] FIG. 19 is a diagram showing the results of an experiment on automatic berthing maneuvering at a virtual pier, and FIG. 20 is a diagram showing each measurement value acquired by the ship information acquisition means in the experiment on automatic berthing maneuvering at a virtual pier. In Figure 19, the actual track, ship position, and true wind direction and speed at that time are plotted at 10-second intervals on the left, and the state of the clutch corresponding to the track is indicated by color on the right. Here, Distance in Figure 20 represents the straight-line distance between the target docking position and the ship's own ship's Quasi-Zenith Satellite System position (this also applies to Figures 22 and 24 described below). Looking at the wake, the deviation from the course decreases as the distance to the pier approaches. On the other hand, it can be seen that during the turning mode, the clutch is intermittently put forward to adjust the ship's heading angle.

[0091] FIG. 21 is a diagram showing the results of an experiment on automatic berthing maneuvering at an actual pier, and FIG. 22 is a diagram showing each measurement value acquired by the ship information acquisition means in the experiment on automatic berthing maneuvering at an actual pier. Unlike the experiment on the virtual pier, the wind direction is roughly opposite, but the path tracking remains good.

[0092] Figure 23 shows the experimental results of automatic berthing maneuvering at a virtual pier under strong winds, and Figure 24 shows the measurement values ​​acquired by the ship information acquisition means in the experiment of automatic berthing maneuvering at a virtual pier under strong winds. To examine wind tracking performance, an experiment was conducted on docking maneuvers at a virtual pier in strong winds. The average true wind speed was 5.34 m / s, with occasions exceeding 8.0 m / s. In this situation, deviation from course increased, but the deviation did not increase even after entering neutral navigation mode, and the ship was able to dock. This is thought to be because the amount of course deviation was compensated for by increasing the amount of steering. [Example]

[0093] To verify the generation of a docking route using Hybrid-state A* in the second embodiment, calculations were performed using the sea area around Innoshima as the experimental sea area. Figure 25 shows a planned route to docking generated using Hybrid-state A*. In this example, a route that avoids obstacles made up of points is shown by lines. In this calculation example, points are placed to surround the land and shallow waters near the pier as obstacles. The map superimposed on the map shows the cost map calculated using dynamic programming, with the numbers at the bottom ranging from 0 to 800, and the darker the color, the higher the cost. The closer to Pier 2 the lower the cost, but on the other hand, at locations where there is an obstacle between them, even if the straight-line distance to Pier 2 is short, it is necessary to go around the obstacle to get to Pier 2, so the overall cost tends to be higher. As for the crucial planned route, it is shown that it connects to Pier 2 from the initial position by going around an area with a breakwater and shallow water, and the desired docking route has been obtained. Looking more closely at the obtained docking route, the route from the starting position to the north side of the shallow water is obtained by Hybrid-state A* node search, and the route from there to Pier 2, consisting of arcs and straight lines, is a Reeds-Shepp path. The total number of nodes expanded by Hybrid-state A* search was 874.

[0094] The experimental vessel "Kamimine," which was also used in Example 1, is equipped with several sensors for monitoring the surrounding environment. Among these, LiDAR can detect obstacles from a distance of 200 to 300 meters or more, depending on the product. A LiDAR (VLP-32C manufactured by Velodyne Lidar) is installed on the deck of the Kamimine, and measurement data during the experiment is recorded. This measurement data was used to generate a path for berthing control. The data used in this experiment was one frame of data taken by LiDAR during the Kamimine's berthing maneuver, and points within 20 meters of the sensor and LiDAR intensity values ​​of 25 or less for each point cloud were excluded as noise. The weather during the measurements was clear. Figure 26 is a diagram showing an example of a docking route calculated using a point cloud measured by LiDAR. The example shown in Figure 26 is a route calculated from the position at the time of measurement. In this sea area, there are no obstacles that would block the course as the ship approaches Pier 2, so the calculated route is composed only of the Reeds-Shepp path, but depending on more complex conditions or the reflection intensity of obstacles, the results may differ. When detecting obstacles using LiDAR, there are cases where a point cloud cannot be obtained at a certain time, and in the example shown in Figure 26, the tip of the breakwater to the left of the center of the image is not detected. In reality, the possibility of detecting such missed areas increases if the measurement distance is reduced, but a preferable solution is to use LiDAR with a higher number of channels, or to use data from several frames in the past to complement the data for areas that were temporarily missed in the measurement, thereby improving the detection probability and accuracy.

[0095] Figure 27 shows an example of calculating a route to a pier while avoiding collisions with obstacles based on LiDAR sensor data, where the ship's position is intentionally changed from the position measured by LiDAR. Note that the LiDAR measurement position and the initial position of the ship are different, and a different point cloud may actually be obtained. As shown in Figure 27, the result was that the ship's bow was heading towards the quay north of Pier 2, then it turned its bow slightly, then it moved backward along the path shown by the line, turned its bow towards Pier 2, and then moved forward to follow the line and reach Pier 2. The total number of nodes searched at this time was 121. In this way, by using LiDAR sensor data, it is possible to calculate a route that avoids obstacles even in situations where obstacle data is not provided in advance. However, since general LiDAR does not provide information on water depth, a separate navigable area must be prepared. Also, since the position of the point cloud in LiDAR data matches the position of obstacles, in order to calculate a route with ample space from the perspective of collision avoidance, it is preferable to take measures such as expanding the rectangular area representing the ship used for collision detection. Additionally, while in this case we calculated a route for one frame of data, there are two ways to actually generate a planned route: global path planning, which first determines a global route, and local path planning, which generates a route on the spot for local obstacle data, as in this case. When using it as local path planning, you can also set a frequency for updating the planned route, or allow some leeway for the path following control to keep up when the planned route changes before and after an update. [Example]

[0096] To demonstrate the effectiveness of the path tracking control incorporating feedforward control for wind disturbance compensation in the third embodiment, an actual ship test was conducted using the experimental ship "Kamimine." This example was conducted in the waters around Innoshima Island (Innoshima Marina) in Onomichi City, Hiroshima Prefecture, as in Example 1. As in Example 1, a path was automatically generated to avoid the shallow waters around Pier 2, and this path was followed. In this experiment, the ship was docked at a floating pier with its starboard side berthed. Figures 28 and 29 show the test results of the wind disturbance compensation path following control of the present invention. Figure 28 shows the test results of an actual ship for pure pursuit with feedback control and berthing control using HCS, and Figure 29 shows the measured values ​​for the state shown in Figure 28. As shown in Figure 29, this experiment was conducted under conditions where the average true wind speed was 6.38 m / s, but the deviation that occurred initially was gradually reduced, and by the time the ship was 50 m away from Pier 2, in other words, before the turning mode, which requires high control precision, the deviation had almost disappeared. The effect of the speed control of this embodiment can be seen when compared with Example 1 (Figs. 23 and 24) which does not have wind disturbance compensation. In this embodiment, clutch switching has been improved and it can be seen that changes in propeller speed are minimized. Furthermore, in this embodiment, the final heading is also sufficiently close to the heading of pier 2 (104 degrees). Considering the subsequent mooring work, it is important to bring the stern close to pier 2, so in that sense too, the improvement in speed control has an effect on the control accuracy of the terminal state.

[0097] Furthermore, to verify the performance of wind disturbance compensation in the third embodiment, an experiment was conducted in windier conditions. The results are shown in Figures 30 and 31. Figure 30 shows the results of an actual ship test of pure pursuit with feedback control and berthing control by HCS in strong winds, and Figure 31 shows the actual measured values ​​for the condition shown in Figure 30. This experiment involved docking control in extremely strong winds with an average true wind speed of 8.86 m / s. Immediately after control began, when the true wind speed reached a maximum of approximately 12 m / s, the ship was initially blown eastward, but quickly made a large turn, eliminating course deviation at a very early stage. The improved clutch control in turning mode also performed ideally with minimal switching. [Industrial Applicability]

[0098] The present invention enables a ship to accurately follow a planned route even under disturbances, thereby supporting and automating ship maneuvering operations that require advanced techniques, such as berthing. Furthermore, even outside the port, other than when berthing, the system can smoothly navigate along a curved planned route. This technology is particularly effective for small ships, which are expected to be more susceptible to disturbances at low speeds, but is also useful for medium to large ships. [Explanation of symbols]

[0099] 10 Route planning means 20 Vessel information acquisition means 30 Pure Pursuit Calculation Method 40 Automatic ship steering calculation means 50 Control Means 60 Automatic Steering Device 61 Speed ​​control means 70 Display means S1, S14 Route planning process S3, S11, S15 Ship information acquisition process S4, S21 Pure pursuit calculation process S5, S22 Automatic ship maneuvering calculation process S6, S16 control process

Claims

1. An automatic guidance method for a ship using an automatic ship steering device that automatically steers at least a sailing ship, comprising: a vessel information acquisition process for acquiring the position, heading, and speed of the vessel; a pure pursuit calculation process for calculating a target point that satisfies predetermined conditions on the planned route in the direction of travel of the vessel based on the position, heading, and speed of the vessel, or for calculating the direction of the target point; an automatic vessel steering calculation process for calculating a steering angle of the vessel based on the target point or the direction and the position or heading of the vessel; and a control process for controlling the automatic vessel steering device based on at least the calculated steering angle, In the planned route generation process, the planned route is divided into a first segmented route controlled in a route following mode, a second segmented route controlled in a neutral navigation mode, a third segmented route controlled in a heading mode, and a fourth segmented route controlled in a stop mode, using the input docking position coordinates, which are the arrival position of the ship, and the docking azimuth, which is the arrival orientation, and the position, heading, and speed of the ship acquired in the ship information acquisition process; generating the third segmented route so that an approach angle of the vessel to the arrival position becomes a predetermined angle when a distance between the position of the vessel and the arrival position reaches a predetermined distance; An automatic guidance method for a ship, characterized in that the fourth segmented route is generated to include an approximately straight line for performing speed control so that the speed of the ship becomes zero when the ship reaches a position where the distance between the position of the ship and the arrival position is shorter than a predetermined distance.

2. In the control process, a first distance determination step of determining whether a straight-line distance D berth from the vessel to the arrival position is greater than a first distance D 1 which is a straight-line distance from the arrival position to a boundary position between the first segmented route and the second segmented route; a second distance determination step of determining whether the straight-line distance Dberth to the arrival position is greater than a second distance D2, which is a straight-line distance to a boundary position between the second segmented route and the third segmented route, when the first distance determination step determines that the straight-line distance Dberth to the arrival position is equal to or less than the first distance D1; a third distance determination step of determining whether or not the straight-line distance D berth to the arrival position is greater than a third distance D 3 that is a straight-line distance to a boundary position between the third segmented route and the fourth segmented route, when the second distance determination step determines that the straight-line distance D berth to the arrival position is equal to or less than the second distance D 2 ; and When it is determined in the first distance determination step that the straight-line distance D berth to the arrival position is greater than the first distance D 1 , control is performed in the path following mode; In the second distance determination step, if it is determined that the straight-line distance D berth to the arrival position is greater than the second distance D 2 , control is performed in the neutral navigation mode; The automatic guidance method for a vessel according to claim 1, characterized in that, when it is determined in the third distance determination process that the straight-line distance D berth to the arrival position is greater than the third distance D 3 , control is performed in the heading mode.

3. 3. The method for automatic guidance of a ship according to claim 1, wherein in the planned route generation process, sea area information is acquired and the planned route is calculated taking into account information on impassable sea areas.

4. A method for automatically guiding a ship according to any one of claims 1 to 3, characterized in that the speed at which the ship will navigate the planned route is calculated during the automatic maneuvering calculation process, and in the control process, a speed control means including a clutch of the automatic maneuvering device is controlled based on the calculated speed.

5. 5. A method for automatic guidance of a ship according to claim 1, wherein meteorological and oceanographic information around the ship is acquired during the ship information acquisition process, and the steering angle and the speed are corrected during the automatic ship maneuvering calculation process by taking into account external forces on the ship based on the meteorological and oceanographic information.

6. The automatic guidance method for a ship described in claim 5, characterized in that the external force on the ship due to wind direction and wind speed obtained as the meteorological and oceanographic information is determined, the hull motion due to the external force is predicted, and the automatic steering device is controlled to derive the steering angle or the speed that will cancel out the hull motion due to the external force, thereby compensating for disturbances caused by wind.

7. An automatic guidance program for a ship using an automatic ship steering device that automatically controls at least the steering of a sailing ship, On the computer, 7. An automatic ship guidance program, comprising: a ship automatic guidance method according to any one of claims 1 to 6; and a program for executing the planned route generation process, the ship information acquisition process, the pure pursuit calculation process, the automatic ship maneuvering calculation process, and the control process in accordance with input of conditions.

8. An automatic guidance system for a ship using an automatic ship steering device that automatically controls at least the steering of a sailing ship, a planned route generation means for calculating a planned route; a vessel information acquisition means for acquiring the position, heading, and speed of the vessel; a pure pursuit calculation means for calculating a target point on the planned route in the direction of travel of the vessel that satisfies predetermined conditions or for calculating the direction of the target point based on the position, heading, and speed of the vessel; an automatic vessel steering calculation means for calculating a steering angle of the vessel based on the target point or the direction and the position or heading of the vessel; and a control means for controlling the automatic vessel steering device based on at least the steering angle of the vessel, The planned route generation means generates the planned route divided into a first segmented route controlled in a route following mode, a second segmented route controlled in a neutral navigation mode, a third segmented route controlled in a heading mode, and a fourth segmented route controlled in a stop mode, using the input docking position coordinates, which are the arrival position of the ship, and the docking azimuth, which is the arrival orientation, and the position, heading, and speed of the ship acquired by the ship information acquisition means, generating the third segmented route so that an approach angle of the vessel to the arrival position becomes a predetermined angle when a distance between the position of the vessel and the arrival position reaches a predetermined distance; An automatic guidance system for a ship, characterized in that the fourth segmented route is generated to include an approximately straight line for performing speed control so that the speed of the ship becomes zero when the ship reaches a position where the distance between the ship's position and the arrival position is shorter than a predetermined distance.

9. In the control means, a first distance determination means for determining whether a straight-line distance Dberth from the vessel to the arrival position is greater than a first distance D1 which is a straight-line distance from the arrival position to a boundary position between the first route segment and the second route segment; a second distance determination means for determining whether the straight-line distance Dberth to the arrival position is greater than a second distance D2, which is a straight-line distance to a boundary position between the second route segment and the third route segment, when the first distance determination means determines that the straight-line distance Dberth to the arrival position is equal to or less than the first distance D1; a third distance determination means for determining whether or not the straight-line distance Dberth to the arrival position is greater than a third distance D3, which is a straight-line distance to a boundary position between the third route segment and the fourth route segment, when the second distance determination means determines that the straight-line distance Dberth to the arrival position is equal to or less than the second distance D2; and When the first distance determination means determines that the straight-line distance D berth to the arrival position is greater than the first distance D 1 , control is performed in the path following mode; when the second distance determination means determines that the straight-line distance D berth to the arrival position is greater than the second distance D 2 , control in the neutral navigation mode; 9. The automatic guidance system for a ship according to claim 8, wherein when the third distance determination means determines that the straight-line distance D berth to the arrival position is greater than the third distance D 3 , the system is controlled in the heading mode.

10. 10. An automatic guidance system for ships according to claim 8 or claim 9, characterized in that the planned route generation means acquires sea area information and calculates the planned route taking into account information on unnavigable sea areas.

11. An automatic guidance system for a ship as described in any one of claims 8 to 10, characterized in that the automatic maneuvering calculation means calculates the speed at which the ship will navigate the planned route, and the control means controls a speed control means including a clutch of the automatic maneuvering device so as to obtain the calculated speed.

12. An automatic guidance system for a ship as described in any one of claims 8 to 11, characterized in that the ship information acquisition means acquires meteorological and oceanographic information around the ship, and the automatic ship maneuvering calculation means corrects the steering angle and the speed by taking into account external forces on the ship based on the meteorological and oceanographic information.

13. The automatic guidance system for a ship described in claim 12, characterized in that the external force on the ship due to wind direction and wind speed obtained as the meteorological and oceanographic information is calculated, the hull motion due to the external force is predicted, and the automatic steering device is controlled to derive the steering angle or the speed that will cancel out the hull motion due to the external force, thereby compensating for disturbances caused by wind.

14. An automatic guidance system for a ship as described in any one of claims 8 to 13, characterized in that it is provided with a display means for displaying at least one of the planned route, the position of the ship, the bow direction, the target point, or the direction of the target point.

15. A ship characterized by being equipped with an automatic guidance system for a ship described in any one of claims 8 to 14.

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