Ship, ship control device, ship control method and program

Abstract

To achieve smooth shift from automatic navigation control of a ship to fixed point holding control of the ship while suppressing thrust of the ship from being generated in a direction against inertial force of the ship when shifting from the automatic navigation control of the ship to the fixed point holding control of the ship.SOLUTION: A ship comprises: an actuator which has a function of generating propulsive power of a ship and a function of causing the ship to generate moment; and a ship control device which activates the actuator. The ship control device can execute automatic navigation control of the ship and fixed point holding control of the ship. The ship control device includes a fixed point holding target position setting part which sets a fixed point holding target position that is a target position of the ship during execution of the fixed point holding control. When the ship control device executes the automatic navigation control of the ship and then executes the fixed point holding control of the ship, the fixed point holding target position setting part sets, as the fixed point holding target position which is different from an automatic navigation stop position that is a position as of when the ship stops the automatic navigation control.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a ship, a ship control device, a ship control method, and a program. [Background technology]

[0002] Conventionally, ships in which a controller executes auto-cruise control are known (see, for example, Patent Document 1). In the technology described in Patent Document 1, a destination of the ship in auto-cruise control is set. Patent Document 1 also describes that auto-cruise control is stopped and fixed-point maintenance control is executed, and in the technology described in Patent Document 1, a target ship speed is set to zero in fixed-point maintenance control, and a propulsion unit is controlled to keep the ship at the destination. As in the technology described in Patent Document 1, when automatic ship navigation control (auto-cruise control) is executed and then fixed-position maintenance control of the ship is executed, at the time when the fixed-position maintenance control of the ship is started, the inertial force (moving speed) generated by the ship trying to stop while the automatic ship navigation control of the ship is being executed remains. Therefore, while the fixed-position maintenance control of the ship is being executed, there is a risk that the inertial force (moving speed) of the ship will cause the ship to pass its destination (the target position of the automatic ship navigation control and fixed-position maintenance control). In order to prevent the ship from passing the target position of the automatic navigation control and fixed position control due to the ship's inertial force (speed) while the ship's fixed position control is being executed, it has conventionally been necessary to generate a thrust for the ship in a direction that counteracts the inertial force (speed) or to execute complex ship speed control at the end of the ship's automatic navigation control (auto-cruise control), as in the technology described in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-094945 A Summary of the Invention [Problem to be solved by the invention]

[0004] In consideration of the above-mentioned problems, the present invention aims to provide a ship, a ship control device, a ship control method, and a program that can achieve a smooth transition from automatic ship navigation control to fixed ship position keeping control while suppressing the generation of ship thrust in a direction that resists the ship's inertial force (gain) that occurs when transitioning from automatic ship navigation control to fixed ship position keeping control. In detail, the present invention aims to provide a ship, ship control device, ship control method and program that can realize a smooth transition from automatic ship navigation control to fixed ship position keeping control, while suppressing the generation of ship thrust in a direction that opposes the ship's inertial force (gain) that occurs when transitioning from automatic ship navigation control to fixed ship position keeping control, without the need to perform complex ship speed control at the end of the ship's automatic ship navigation control as in the technology described in Patent Document 1. [Means for solving the problem]

[0005] One aspect of the present invention comprises an actuator having a function of generating a propulsive force for a ship and a function of generating a moment on the ship, and a ship control device which operates the actuator, wherein the ship control device is capable of executing automatic sailing control of the ship and fixed position keeping control of the ship, and the ship control device comprises a fixed position keeping target position setting unit which sets a fixed position keeping target position which is a target position of the ship while the fixed position keeping control of the ship is being executed, and when the ship control device executes the automatic sailing control of the ship and then executes the fixed position keeping control of the ship, the fixed position keeping target position setting unit: At a time when it can be estimated that the movement of the vessel due to the speed of the vessel has ended after the automatic navigation control is stopped, A position different from the automatic navigation stop position, which is the position of the ship when the automatic navigation control of the ship is stopped. The position where the movement of the ship due to the speed of the ship can be estimated to have ended is The fixed point holding target position is set as a ship.

[0006] One aspect of the present invention is a ship control device that operates an actuator having a function of generating a propulsive force for a ship and a function of generating a moment on the ship, the ship control device being capable of executing automatic sailing control of the ship and fixed position keeping control of the ship, the ship control device including a fixed position keeping target position setting unit that sets a fixed position keeping target position that is a target position of the ship while the fixed position keeping control of the ship is being executed, and when the ship control device executes the automatic sailing control of the ship and then executes the fixed position keeping control of the ship, the fixed position keeping target position setting unit: At a time when it can be estimated that the movement of the vessel due to the speed of the vessel has ended after the automatic navigation control is stopped, A position different from the automatic navigation stop position, which is the position of the ship when the automatic navigation control of the ship is stopped. The position where the movement of the ship due to the speed of the ship can be estimated to have ended is The vessel control device sets the fixed point as the fixed point holding target position.

[0007] One aspect of the present invention is a ship control method for a ship control device that operates an actuator having a function of generating a propulsive force for a ship and a function of generating a moment on the ship, the method comprising: an automatic sailing control step in which the ship control device executes automatic sailing control of the ship; a fixed point maintenance control step in which the ship control device executes fixed point maintenance control of the ship; and a fixed point maintenance target position setting step in which the ship control device sets a fixed point maintenance target position that is a target position of the ship while the ship control device is executing the fixed point maintenance control of the ship, and when the automatic sailing control step is executed and then the fixed point maintenance control step is executed, in the fixed point maintenance target position setting step: At a time when it can be estimated that the movement of the vessel due to the speed of the vessel has ended after the automatic navigation control is stopped, A position different from the automatic navigation stop position, which is the position of the ship when the automatic navigation control of the ship is stopped. The position where the movement of the ship due to the speed of the ship can be estimated to have ended is The fixed point maintaining target position is set as the fixed point maintaining target position.

[0008] One aspect of the present invention is a program for causing a computer mounted on a vessel control device that operates an actuator having a function of generating a propulsive force for a vessel and a function of generating a moment on the vessel to execute an automatic navigation control step of executing an automatic navigation control of the vessel, a fixed point maintenance control step of executing a fixed point maintenance control of the vessel, and a fixed point maintenance target position setting step of setting a fixed point maintenance target position which is a target position of the vessel during execution of the fixed point maintenance control of the vessel, wherein when the automatic navigation control step is executed and then the fixed point maintenance control step is executed, in the fixed point maintenance target position setting step: At a time when it can be estimated that the movement of the vessel due to the speed of the vessel has ended after the automatic navigation control is stopped, A position different from the automatic navigation stop position, which is the position of the ship when the automatic navigation control of the ship is stopped. The position where the movement of the ship due to the speed of the ship can be estimated to have ended is The fixed point is set as the target position. Effect of the Invention

[0009] According to the present invention, it is possible to provide a ship, ship control device, ship control method and program that can realize a smooth transition from automatic ship navigation control to fixed ship position keeping control while suppressing the generation of ship thrust in a direction that opposes the ship's inertial force (gait) that occurs when transitioning from automatic ship navigation control to fixed ship position keeping control. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing an example of a ship to which a ship control device according to a first embodiment is applied. [Diagram 2] 2A to 2C are diagrams for explaining an example of ship behavior when the ship control device of the first embodiment executes automatic sailing control and then executes fixed position keeping control. [Diagram 3] 5 is a flowchart illustrating an example of a process executed in a ship to which the ship control device of the first embodiment is applied. [Figure 4] 10 is a flowchart illustrating an example of a process executed in a ship to which a ship control device according to a second embodiment is applied. [Diagram 5]FIG. 11 is a diagram for explaining an example of behavior of the ship when the ship control device of the third embodiment executes automatic sailing control and then executes fixed position keeping control. [Figure 6] FIG. 13 is a diagram showing an example of a ship to which a ship control device according to a fifth embodiment is applied. [Figure 7] FIG. 13 is a diagram for explaining an example of behavior of the ship when the ship control device of the fifth embodiment executes automatic sailing control and then executes fixed position keeping control. [Figure 8] 13 is a flowchart illustrating an example of a process executed in a ship or the like to which a ship control device according to a fifth embodiment is applied. [Figure 9] 13 is a flowchart illustrating an example of a process executed in a ship or the like to which a ship control device according to a sixth embodiment is applied. [Figure 10] FIG. 13 is a diagram showing an example of a ship to which a ship control device according to a seventh embodiment is applied. [Figure 11] 13 is a flowchart illustrating an example of a process executed in a ship or the like to which a ship control device according to a seventh embodiment is applied. [Figure 12] 13 is a flowchart illustrating an example of a process executed in a ship or the like to which a ship control device according to an eighth embodiment is applied. [Figure 13] FIG. 13 is a diagram for explaining the behavior of a ship in a comparative example when automatic navigation control is executed and then fixed position maintenance control is executed. [Figure 14] 10 is a flowchart for explaining a process executed in a ship of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Before describing an embodiment of a ship, a ship control device, a ship control method, and a program according to the present invention, a ship control method of a comparative example will be described. Fig. 13 is a diagram for explaining the behavior of the ship R1 of the comparative example when automatic navigation control is executed and then fixed position maintenance control is executed. Fig. 14 is a flowchart for explaining the processing executed in the ship R1 of the comparative example. In the comparative example shown in FIGS. 13 and 14, in step SA in FIG. 14, a target position RTP (see FIG. 13(B)) for the automatic navigation control and fixed position keeping control is set, for example, by the operator of the ship R1. Next, in step SB, the ship R1 receives an automatic navigation start command from, for example, the operator of the ship R1, and the ship R1 starts automatic navigation (i.e., automatic navigation control of the ship R1 is started). As a result, as shown in Fig. 13(A), the ship R1 moves toward the target position RTP of the automatic navigation control and the fixed position keeping control. Next, in step SC, it is determined whether or not to stop automatic navigation. As shown in Fig. 13(A), if the ship R1 has not reached the target position RTP of the automatic navigation control and fixed position keeping control, step SC is repeatedly executed. On the other hand, as shown in Fig. 13(B), if the ship R1 has reached the target position RTP of the automatic navigation control and fixed position keeping control, automatic navigation is stopped (i.e., the propulsive force of the ship R1 is set to zero), and in step SD, fixed position keeping control of the ship R1 is started. In other words, the position of the ship R1 when the automatic navigation control of the ship R1 is stopped is the target position RTP of the automatic navigation control and fixed position keeping control.

[0012] At the time when the fixed position maintenance control of the vessel R1 is started, the inertial force (starting speed) generated by the vessel R1, which was moving when the automatic navigation control of the vessel R1 was being executed, attempting to stop remains. Therefore, during the execution of the fixed position maintenance control of the vessel R1, as shown in Fig. 13(C), the inertial force (starting speed) of the vessel R1 causes the vessel R1 to pass the target position RTP of the automatic navigation control and the fixed position maintenance control. As a result, while the fixed position maintenance control of the vessel R1 is being executed, a propulsive force of the vessel R1 is generated in a direction (downward in FIG. 13) that resists the inertial force (footfall) of the vessel R1, as shown by an arrow in FIG. 13(D). The greater the inertial force (footfall) of the vessel R1 at the time when the fixed position maintenance control of the vessel R1 is started, the greater the propulsive force of the vessel R1 that resists the inertial force (footfall). Therefore, when the propulsive force of the vessel R1 in the direction that resists the inertial force (footfall) is large, passengers of the vessel R1 who did not anticipate the generation of the propulsive force of the vessel R1 in the direction that resists the inertial force (footfall) may feel uneasy.

[0013] Next, in step SE, it is determined whether or not to stop (end) the fixed position keeping control. As shown in Fig. 13(D), if the ship R1 has not yet returned to the target position RTP of the automatic navigation control and the fixed position keeping control, step SE is repeatedly executed. On the other hand, as shown in Fig. 13(E), if the ship R1 has returned to the target position RTP of the automatic navigation control and the fixed position keeping control, in step SF, the generation of the propulsive force of the ship R1 is stopped (i.e., the propulsive force of the ship R1 is set to zero).

[0014] First Embodiment A first embodiment of a ship, a ship control device, a ship control method, and a program according to the present invention will be described below. FIG. 1 is a diagram showing an example of a ship 1 to which a ship control device 1C according to a first embodiment is applied. The ship control device 1C of the first embodiment can be applied to any type of ship 1, such as a personal watercraft (PWC) having functions similar to those of the PWC (jet ski) described in Figure 1 of Japanese Patent No. 5196649, a ship not equipped with a jet propulsion engine (for example, a ship equipped with an outboard motor described in Japanese Patent No. 6198192, Japanese Unexamined Patent Publication No. 2007-22284, etc., a ship equipped with an inboard / outboard motor or an inboard engine, a large ship equipped with a side thruster, etc.). In the example shown in FIG. 1, a ship 1 includes an actuator 1A, an operation unit 1B, a ship control device 1C, a ship position detection unit 1D, a bow direction detection unit 1E, and a ship speed detection unit 1F. The actuator 1A includes a rudder section 1A1 and a thrust generating section 1A2. The rudder section 1A1 has a function of generating a moment in the vessel 1. The thrust generating section 1A2 has a function of generating a propulsive force for the vessel 1. In an example in which the vessel 1 is a PWC, the actuator 1A includes, for example, an engine, a nozzle, a deflector, a trim actuator, a bucket, a bucket actuator, etc., as described in FIG. 1 of JP 2019-171925 A.

[0015] In the example shown in Fig. 1, the operation unit 1B accepts input of operations (e.g., instructions) by the operator of the ship 1. The operation unit 1B includes, for example, a steering unit 1B1, a throttle operation unit 1B2, an automatic navigation target position setting unit 1B3, an automatic navigation start instruction input unit 1B4, an automatic navigation stop instruction input unit 1B5, and a fixed position hold stop instruction input unit 1B6. The steering unit 1B1 accepts input operations by the operator to operate the rudder unit 1A1. The throttle operation unit 1B2 accepts input operations by the operator to operate the thrust generating unit 1A2. In an example in which the vessel 1 is a PWC, the steering unit 1B1 and the throttle operating unit 1B2 are configured in a similar manner to, for example, the steering handle device described in Figure 1 of Patent Gazette No. 5196649, or the steering unit described in Figure 1 of Patent Publication No. 2019-171925.

[0016] 1, the automatic navigation target position setting unit 1B3 accepts the setting of a target position for automatic navigation control of the ship 1, for example, by the operator of the ship 1. The automatic navigation start instruction input unit 1B4 accepts the input of an instruction to start automatic navigation control of the ship 1, for example, by the operator of the ship 1. The automatic navigation stop instruction input unit 1B5 accepts the input of an instruction to stop automatic navigation control of the ship 1, for example, by the operator of the ship 1. The fixed position maintenance stop instruction input unit 1B6 accepts the input of an instruction to stop fixed position maintenance control of the ship 1, for example, by the operator of the ship 1. The ship control device 1C performs control such as operating the actuator 1A based on input operations from the operator of the ship 1 received by the operation unit 1B. The ship control device 1C can execute automatic navigation control of the ship 1 and fixed-point maintenance control of the ship 1. The ship control device 1C includes an actuator control unit 1C1 and a fixed-point maintenance target position setting unit 1C2. The actuator control unit 1C1 controls the actuator 1A. In other words, the actuator control unit 1C1 operates the actuator 1A. The fixed-point maintenance target position setting unit 1C2 sets a fixed-point maintenance target position, which is a target position of the ship 1 while fixed-point maintenance control of the ship 1 is being executed.

[0017] The ship position detection unit 1D detects the position of the ship 1. The ship position detection unit 1D includes, for example, a GPS (Global Positioning System) device. The GPS device calculates the position coordinates of the ship 1 by receiving signals from a plurality of GPS satellites. The bow direction detection unit 1E detects the bow direction of the ship 1. The bow direction detection unit 1E includes, for example, a direction sensor. The direction sensor calculates the bow direction of the ship 1 by using, for example, geomagnetism. In another example, the orientation sensor may be a device (gyrocompass) in which a north-pointing device and a vibration-damping device are added to a rapidly rotating gyroscope so that the orientation sensor always indicates north. In yet another example, the orientation sensor may be a GPS compass that includes multiple GPS antennas and calculates the ship's heading from the relative positions of the multiple GPS antennas.

[0018] 1, the boat speed detection unit 1F detects the speed of the boat 1. The boat speed detection unit 1F may be, for example, a water pressure sensing type that detects the water speed of the boat 1, or a GPS measurement type that detects the ground speed of the boat 1.

[0019] Fig. 2 is a diagram for explaining an example of the behavior of the ship 1 when the ship control device 1C of the first embodiment executes automatic navigation control and then executes fixed position keeping control. Fig. 3 is a flowchart for explaining an example of processing executed in the ship 1 to which the ship control device 1C of the first embodiment is applied. In the example shown in Figures 2 and 3, in step S11 of Figure 3, the automatic navigation target position setting unit 1B3 accepts the setting of an automatic navigation target position TP1 (see Figure 2 (B)), which is a target position for automatic navigation control of the ship 1, for example, by the operator of the ship 1. Next, in step S12, the automatic navigation start instruction input unit 1B4 accepts an input of an instruction to start automatic navigation control of the ship 1, for example, by the operator of the ship 1. As a result, the ship control device 1C starts automatic navigation control of the ship 1 (i.e., the ship 1 starts automatic navigation), and the ship 1 moves toward the automatic navigation target position TP1, as shown in Fig. 2(A). Next, in step S13, the ship control device 1C judges whether or not to stop the automatic navigation control of the ship 1. When the ship control device 1C judges not to stop the automatic navigation control of the ship 1 (in detail, when the position of the ship 1 detected by the ship position detection unit 1D does not approximately match the automatic navigation target position TP1 (i.e., when the ship 1 has not reached the automatic navigation target position TP1) and the automatic navigation stop instruction input unit 1B5 has not received an input of an instruction to stop the automatic navigation control of the ship 1 by the operator of the ship 1 or the like), step S13 is repeatedly executed. On the other hand, when the ship control device 1C judges to stop the automatic navigation control of the ship 1 (in detail, when the position of the ship 1 detected by the ship position detection unit 1D approximately matches the automatic navigation target position TP1 (i.e., when the ship 1 has reached the automatic navigation target position TP1) or when the automatic navigation stop instruction input unit 1B5 has received an input of an instruction to stop the automatic navigation control of the ship 1 by the operator of the ship 1 or the like), the process proceeds to step S14.

[0020] 2(B), the position of the ship 1 detected by the ship position detection unit 1D roughly coincides with the automatic navigation target position TP1 (i.e., the ship 1 has reached the automatic navigation target position TP1), so the automatic navigation of the ship 1 is stopped (i.e., the ship control device 1C stops the automatic navigation control of the ship 1), and the ship control device 1C stops the generation of propulsion force for the ship 1 by the actuator 1A. In other words, the position of the ship 1 when the automatic navigation control of the ship 1 is stopped is the automatic navigation target position TP1. On the other hand, at the time shown in Fig. 2(B), there remains an inertial force (starting speed) caused by the ship 1 trying to stop while moving when the automatic navigation control of the ship 1 is being executed. Therefore, as shown in Fig. 2(C), the ship 1 continues to move due to the inertial force (starting speed) of the ship 1. Therefore, in the example shown in Fig. 2 and Fig. 3, in step S14, the ship control device 1C monitors the speed of the ship 1. More specifically, in step S14, the ship control device 1C determines whether the speed of the ship 1 detected by the ship speed detection unit 1F has decreased to a first threshold value or less. If the speed of the ship 1 has not decreased to a first threshold value or less (i.e., the ship 1 continues to move due to the inertial force (footfall) of the ship 1), step S14 is repeatedly executed. On the other hand, if the speed of the ship 1 has decreased to a first threshold value or less (i.e., it can be estimated that the movement of the ship 1 due to the inertial force (footfall) of the ship 1 has ended), the process proceeds to step S15.

[0021] In step S15, the fixed point keeping target position setting unit 1C2 sets the position of the ship 1 detected by the ship position detection unit 1D as the fixed point keeping target position TP2 (see Figure 2 (C)), which is the target position of the ship 1 while fixed point keeping control of the ship 1 is being executed. Next, in step S16, the vessel control device 1C starts the fixed position keeping control of the vessel 1. Next, in step S17, the ship control device 1C determines whether or not to stop the fixed position holding control of the ship 1. If the ship control device 1C determines not to stop the fixed position holding control of the ship 1 (more specifically, if the fixed position holding stop instruction input unit 1B6 of the operation unit 1B has not received an input of an instruction to stop the fixed position holding control of the ship 1 by the operator of the ship 1 or the like), step S17 is repeatedly executed. On the other hand, if the ship control device 1C determines to stop the fixed position holding control of the ship 1 (more specifically, if the fixed position holding stop instruction input unit 1B6 of the operation unit 1B has received an input of an instruction to stop the fixed position holding control of the ship 1 by the operator of the ship 1 or the like), the process proceeds to step S18. In step S18, the ship control device 1C stops the fixed position holding control of the ship 1 and stops generating the propulsion force of the ship 1 by the actuator 1A (more specifically, the thrust of the ship 1 for holding the ship 1 at the fixed position holding target position TP2 (see Figure 2 (D)) against external disturbances such as wind and currents).

[0022] That is, in the example shown in Figures 1 to 3, when the ship control device 1C performs automatic navigation control of the ship 1 and then performs fixed point maintenance control of the ship 1, the fixed point maintenance target position setting unit 1C2 sets a position different from the position of the ship 1 when the automatic navigation control of the ship 1 is stopped (in the example shown in Figure 2, the automatic navigation target position TP1) as the fixed point maintenance target position TP2 (see Figure 2 (C)). Therefore, in the example shown in Figures 1 to 3, the generation of thrust of the ship 1 in a direction that resists the inertial force (speed) of the ship 1 that occurs when transitioning from the automatic navigation control of the ship 1 to the fixed position keeping control of the ship 1 is suppressed, while there is no need to perform complex ship speed control at the end of the automatic navigation control of the ship 1 as in the technology described in Patent Document 1, and a smooth transition from the automatic navigation control of the ship 1 to the fixed position keeping control of the ship 1 can be realized (in other words, the behavior of the ship 1 can be made seamless and passengers on board the ship 1 can be given a sense of security). In the example shown in Figures 1 to 3, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C stops the generation of propulsion and thrust for the ship 1 by the actuator 1A. However, in other examples, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C may cause the actuator 1A to generate thrust in a direction that resists the inertial force generated by the stopping of the automatic navigation control of the ship 1. Furthermore, in the example shown in Figures 1 to 3, the position of the ship 1 detected by the ship position detection unit 1D when step S15 in Figure 3 is executed is set as the fixed point maintenance target position TP2, but in other examples, the position of the ship 1 where the speed of the ship 1 will be zero may be predicted based on the speed of the ship 1 when step S15 in Figure 3 is executed, and the predicted position may be set as the fixed point maintenance target position TP2.

[0023] <Second embodiment> A second embodiment of the ship, ship control device, ship control method, and program of the present invention will be described below. The boat 1 of the second embodiment is configured similarly to the boat 1 of the above-described first embodiment, except for the points described below. Therefore, the boat 1 of the second embodiment can achieve the same effects as the boat 1 of the above-described first embodiment, except for the points described below.

[0024] The ship 1 to which the ship control device 1C of the second embodiment is applied has the same configuration as the ship 1 to which the ship control device 1C of the first embodiment shown in FIG. 1 is applied.

[0025] FIG. 4 is a flowchart illustrating an example of a process executed in the boat 1 to which the boat control device 1C of the second embodiment is applied. In the example shown in Figure 4, in step S21, the automatic navigation target position setting unit 1B3 accepts the setting of an automatic navigation target position TP1 (see Figure 2 (B)), which is the target position for automatic navigation control of the ship 1, for example, by the operator of the ship 1, similar to step S11 in Figure 3. Next, in step S22, the automatic navigation start instruction input unit 1B4 accepts an input of an instruction to start automatic navigation control of the ship 1, for example, by the operator of the ship 1, similar to step S12 in Fig. 3. As a result, the ship control device 1C starts automatic navigation control of the ship 1 (i.e., the ship 1 starts automatic navigation), and the ship 1 moves toward the automatic navigation target position TP1 as shown in Fig. 2(A). Next, in step S23, the ship controlling device 1C determines whether or not to stop the automatic navigation control of the ship 1, similar to step S13 in Fig. 3. If the ship controlling device 1C determines not to stop the automatic navigation control of the ship 1, step S23 is repeatedly executed. On the other hand, if the ship controlling device 1C determines to stop the automatic navigation control of the ship 1, the process proceeds to step S24.

[0026] 2(B), since the position of the ship 1 detected by the ship position detection unit 1D roughly coincides with the automatic navigation target position TP1, automatic navigation of the ship 1 is stopped and the ship control device 1C stops the generation of propulsion force of the ship 1 by the actuator 1A. In other words, the position of the ship 1 when the automatic navigation control of the ship 1 is stopped is the automatic navigation target position TP1. As described above, at the time point shown in Fig. 2(B), the inertial force (starting speed) generated by the ship 1 attempting to stop while moving during execution of the automatic navigation control of the ship 1 remains. Therefore, as shown in Fig. 2(C), the ship 1 continues to move due to the inertial force (starting speed) of the ship 1. Therefore, in the example shown in Fig. 2 and Fig. 4, in step S24, the ship control device 1C monitors the elapsed time since the automatic navigation control of the ship 1 was stopped. More specifically, in step S24, the ship control device 1C determines whether the elapsed time since the automatic navigation control of the ship 1 was stopped is equal to or greater than a second threshold value. If the elapsed time is not equal to or greater than the second threshold value (i.e., it can be assumed that the ship 1 is continuing to move due to the inertial force (gait) of the ship 1), step S24 is repeatedly executed. On the other hand, if the elapsed time is equal to or greater than the second threshold value (i.e., it can be assumed that the movement of the ship 1 due to the inertial force (gait) of the ship 1 has ended), the process proceeds to step S25.

[0027] In step S25, the fixed point holding target position setting unit 1C2, similar to step S15 in Figure 3, sets the position of the ship 1 detected by the ship position detection unit 1D as the fixed point holding target position TP2 (see Figure 2 (C)), which is the target position of the ship 1 while fixed point holding control of the ship 1 is being executed. Next, in step S26, the vessel controlling device 1C starts fixed position keeping control of the vessel 1, similarly to step S16 in FIG. Next, in step S27, the ship control device 1C determines whether or not to stop the fixed position maintenance control of the ship 1, similar to step S17 in Fig. 3. If the ship control device 1C determines not to stop the fixed position maintenance control of the ship 1, step S27 is repeatedly executed. On the other hand, if the ship control device 1C determines to stop the fixed position maintenance control of the ship 1, the process proceeds to step S28. In step S28, the vessel control device 1C stops the fixed position maintenance control of the vessel 1, and stops the generation of thrust for the vessel 1 by the actuator 1A, similarly to step S18 in FIG.

[0028] That is, in the example shown in Figures 2 and 4, when the ship control device 1C performs automatic navigation control of the ship 1 and then performs fixed point maintenance control of the ship 1, the fixed point maintenance target position setting unit 1C2 sets a position different from the position of the ship 1 when the automatic navigation control of the ship 1 is stopped (in the example shown in Figure 2, the automatic navigation target position TP1) as the fixed point maintenance target position TP2. Therefore, in the example shown in Figures 2 and 4, the generation of thrust of the ship 1 in a direction that resists the inertial force (speed) of the ship 1 that occurs when transitioning from the automatic navigation control of the ship 1 to the fixed position keeping control of the ship 1 is suppressed, while there is no need to perform complex ship speed control at the end of the automatic navigation control of the ship 1 as in the technology described in Patent Document 1, and a smooth transition from the automatic navigation control of the ship 1 to the fixed position keeping control of the ship 1 can be realized (in other words, the behavior of the ship 1 can be made seamless and passengers on board the ship 1 can be given a sense of security). In the example shown in Figures 2 and 4, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C stops the generation of propulsion and thrust for the ship 1 by the actuator 1A, but in other examples, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C may cause the actuator 1A to generate thrust in a direction that resists the inertial force generated by the stopping of the automatic navigation control of the ship 1.

[0029] <Third embodiment> A third embodiment of the ship, the ship control device, the ship control method, and the program of the present invention will be described below. The boat 1 of the third embodiment is configured similarly to the boat 1 of the above-described first embodiment, except for the points described below. Therefore, the boat 1 of the third embodiment can achieve the same effects as the boat 1 of the above-described first embodiment, except for the points described below.

[0030] The ship 1 to which the ship control device 1C of the third embodiment is applied has the same configuration as the ship 1 to which the ship control device 1C of the first embodiment shown in FIG. 1 is applied.

[0031] FIG. 5 is a diagram for explaining an example of behavior of the ship 1 in a case where the ship control device 1C according to the third embodiment executes automatic sailing control and then executes fixed position keeping control. In the boat 1 to which the boat control device 1C of the third embodiment is applied, a process similar to the process shown in FIG. 3 is executed. In the example shown in Figures 3 and 5, in step S11 of Figure 3, the automatic navigation target position setting unit 1B3 accepts the setting of an automatic navigation target position TP1 (see Figure 5 (D)), which is a target position for automatic navigation control of the ship 1, for example, by the operator of the ship 1. Next, in step S12, the automatic navigation start instruction input unit 1B4 accepts an input of an instruction to start automatic navigation control of the ship 1, for example, by the operator of the ship 1. As a result, the ship control device 1C starts automatic navigation control of the ship 1 (i.e., the ship 1 starts automatic navigation), and the ship 1 moves toward the automatic navigation target position TP1, as shown in Fig. 5(A). Next, in step S13, the ship control device 1C judges whether or not to stop the automatic navigation control of the ship 1. When the ship control device 1C judges not to stop the automatic navigation control of the ship 1 (in detail, when the position of the ship 1 detected by the ship position detection unit 1D does not approximately match the automatic navigation target position TP1 (i.e., when the ship 1 has not reached the automatic navigation target position TP1) and the automatic navigation stop instruction input unit 1B5 has not received an input of an instruction to stop the automatic navigation control of the ship 1 by the operator of the ship 1 or the like), step S13 is repeatedly executed. On the other hand, when the ship control device 1C judges to stop the automatic navigation control of the ship 1 (in detail, when the position of the ship 1 detected by the ship position detection unit 1D approximately matches the automatic navigation target position TP1 (i.e., when the ship 1 has reached the automatic navigation target position TP1) or when the automatic navigation stop instruction input unit 1B5 has received an input of an instruction to stop the automatic navigation control of the ship 1 by the operator of the ship 1 or the like), the process proceeds to step S14.

[0032] In the example shown in Figure 5 (B), before the ship 1 reaches the automatic navigation target position TP1, the automatic navigation stop instruction input unit 1B5 receives an input of an instruction to stop automatic navigation control of the ship 1 from the operator of the ship 1 or the like, so that the automatic navigation of the ship 1 is stopped (i.e., the ship control device 1C stops the automatic navigation control of the ship 1), and the ship control device 1C stops the generation of propulsion force for the ship 1 by the actuator 1A. On the other hand, at the time shown in Fig. 5(B), there remains an inertial force (starting speed) caused by the ship 1 trying to stop while moving during execution of the automatic navigation control of the ship 1. Therefore, as shown in Fig. 5(C), the ship 1 continues to move due to the inertial force (starting speed) of the ship 1. Therefore, in the example shown in Fig. 3 and Fig. 5, in step S14, the ship control device 1C monitors the speed of the ship 1. More specifically, in step S14, the ship control device 1C determines whether the speed of the ship 1 detected by the ship speed detection unit 1F has decreased to a first threshold value or less. If the speed of the ship 1 has not decreased to a first threshold value or less (i.e., the ship 1 continues to move due to the inertial force (foot motion) of the ship 1), step S14 is repeatedly executed. On the other hand, if the speed of the ship 1 has decreased to a first threshold value or less (i.e., it can be estimated that the movement of the ship 1 due to the inertial force (foot motion) of the ship 1 has ended), the process proceeds to step S15.

[0033] In step S15, the fixed point keeping target position setting unit 1C2 sets the position of the ship 1 detected by the ship position detection unit 1D as the fixed point keeping target position TP2 (see Figure 5 (C)), which is the target position of the ship 1 while fixed point keeping control of the ship 1 is being executed. Next, in step S16, the vessel control device 1C starts the fixed position keeping control of the vessel 1. Next, in step S17, the ship control device 1C determines whether or not to stop the fixed position holding control of the ship 1. If the ship control device 1C determines not to stop the fixed position holding control of the ship 1 (more specifically, if the fixed position holding stop instruction input unit 1B6 of the operation unit 1B has not received an input of an instruction to stop the fixed position holding control of the ship 1 by the operator of the ship 1 or the like), step S17 is repeatedly executed. On the other hand, if the ship control device 1C determines to stop the fixed position holding control of the ship 1 (more specifically, if the fixed position holding stop instruction input unit 1B6 of the operation unit 1B has received an input of an instruction to stop the fixed position holding control of the ship 1 by the operator of the ship 1 or the like), the process proceeds to step S18. In step S18, the ship control device 1C stops the fixed position holding control of the ship 1 and stops generating the propulsion force of the ship 1 by the actuator 1A (more specifically, the thrust of the ship 1 for holding the ship 1 at the fixed position holding target position TP2 (see Figure 5 (E)) against external disturbances such as wind and currents).

[0034] That is, in the example shown in Figures 3 and 5, when the ship control device 1C executes automatic navigation control of the ship 1 and then executes fixed position maintenance control of the ship 1, the fixed position maintenance target position setting unit 1C2 sets a position different from the position TPX of the ship 1 when the automatic navigation control of the ship 1 is stopped (see Figure 5(B)) as the fixed position maintenance target position TP2 (see Figure 5(C)). In detail, the fixed position maintenance target position setting unit 1C2 sets as the fixed position maintenance target position TP2 a position different from the position TPX of the ship 1 detected by the ship position detection unit 1D at the time when the automatic navigation stop instruction input unit 1B5 accepts input of an instruction to stop the automatic navigation control of the ship 1 by the operator of the ship 1 or the like. Therefore, in the example shown in Figures 3 and 5, the generation of thrust of the ship 1 in a direction that resists the inertial force (speed) of the ship 1 that occurs when transitioning from the automatic navigation control of the ship 1 to the fixed position keeping control of the ship 1 is suppressed, while there is no need to perform complex ship speed control at the end of the automatic navigation control of the ship 1 as in the technology described in Patent Document 1, and a smooth transition from the automatic navigation control of the ship 1 to the fixed position keeping control of the ship 1 can be realized (in other words, the behavior of the ship 1 can be made seamless and passengers on board the ship 1 can be given a sense of security). In the example shown in Figures 3 and 5, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C stops the generation of propulsion and thrust for the ship 1 by the actuator 1A, but in other examples, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C may cause the actuator 1A to generate thrust in a direction that resists the inertial force generated by the stopping of the automatic navigation control of the ship 1.

[0035] <Fourth embodiment> A fourth embodiment of the ship, the ship control device, the ship control method, and the program of the present invention will be described below. The ship 1 of the fourth embodiment is configured similarly to the ships 1 of the first and third embodiments described above, except for the points described below. Therefore, the ship 1 of the fourth embodiment can achieve the same effects as the ships 1 of the first and third embodiments described above, except for the points described below.

[0036] The ship 1 to which the ship control device 1C of the fourth embodiment is applied has the same configuration as the ship 1 to which the ship control device 1C of the first embodiment shown in FIG. 1 is applied. In the boat 1 to which the boat control device 1C of the fourth embodiment is applied, a process similar to the process shown in FIG. 4 is executed.

[0037] In an example of a ship 1 to which the ship control device 1C of the fourth embodiment is applied, in step S21 of Figure 4, the automatic navigation target position setting unit 1B3 accepts the setting of an automatic navigation target position TP1 (see Figure 5 (D)), which is a target position for automatic navigation control of the ship 1, for example, by the operator of the ship 1. Next, in step S22 in Fig. 4, the automatic navigation start instruction input unit 1B4 accepts an input of an instruction to start automatic navigation control of the ship 1, for example, by the operator of the ship 1. As a result, the ship control device 1C starts automatic navigation control of the ship 1 (i.e., the ship 1 starts automatic navigation), and the ship 1 moves toward the automatic navigation target position TP1, as shown in Fig. 5(A). 4, the ship control device 1C determines whether or not to stop the automatic navigation control of the ship 1. If the ship control device 1C determines not to stop the automatic navigation control of the ship 1, step S23 is repeatedly executed. On the other hand, if the ship control device 1C determines to stop the automatic navigation control of the ship 1, the process proceeds to step S24.

[0038] In the example shown in Figure 5 (B), before the ship 1 reaches the automatic navigation target position TP1, the automatic navigation stop instruction input unit 1B5 receives an input of an instruction to stop automatic navigation control of the ship 1 from the operator of the ship 1 or the like, so that the automatic navigation of the ship 1 is stopped (i.e., the ship control device 1C stops the automatic navigation control of the ship 1), and the ship control device 1C stops the generation of propulsion force for the ship 1 by the actuator 1A. On the other hand, at the time shown in Fig. 5(B), there remains an inertial force (starting speed) caused by the ship 1 trying to stop while moving during execution of the automatic navigation control of the ship 1. Therefore, as shown in Fig. 5(C), the ship 1 continues to move due to the inertial force (starting speed) of the ship 1. Therefore, in an example of the ship 1 to which the ship control device 1C of the fourth embodiment is applied, in step S24 of FIG. 4, the ship control device 1C monitors the elapsed time from when the automatic navigation stop instruction input unit 1B5 receives an input of an instruction to stop the automatic navigation control of the ship 1 by the operator of the ship 1 or the like (when the automatic navigation control is stopped). In detail, in step S24 of FIG. 4, the ship control device 1C determines whether the elapsed time from when the automatic navigation stop instruction input unit 1B5 receives an input of an instruction to stop the automatic navigation control of the ship 1 by the operator of the ship 1 or the like is equal to or greater than a second threshold value. If the elapsed time is not equal to or greater than the second threshold value (i.e., if it can be estimated that the ship 1 is continuing to move due to the inertial force (foot) of the ship 1), step S24 of FIG. 4 is repeatedly executed. On the other hand, if the elapsed time is equal to or greater than the second threshold value (i.e., if it can be estimated that the movement of the ship 1 due to the inertial force (foot) of the ship 1 has ended), the process proceeds to step S25 of FIG. 4.

[0039] In step S25 of Figure 4, the fixed point maintenance target position setting unit 1C2 sets the position of the ship 1 detected by the ship position detection unit 1D as the fixed point maintenance target position TP2 (see Figure 5 (C)), which is the target position of the ship 1 while fixed point maintenance control of the ship 1 is being executed. Next, in step S26 of FIG. 4, the vessel controlling device 1C starts fixed position keeping control of the vessel 1. Next, in step S27 of Fig. 4, the ship controlling device 1C determines whether or not to stop the fixed position holding control of the ship 1. If the ship controlling device 1C determines not to stop the fixed position holding control of the ship 1, step S27 of Fig. 4 is repeatedly executed. On the other hand, if the ship controlling device 1C determines to stop the fixed position holding control of the ship 1, the process proceeds to step S28 of Fig. 4. In step S28 of FIG. 4, the vessel control device 1C stops the fixed position holding control of the vessel 1, and stops the generation of thrust for the vessel 1 by the actuator 1A.

[0040] That is, in one example of a ship 1 to which the ship control device 1C of the fourth embodiment is applied, when the ship control device 1C executes automatic navigation control of the ship 1 and then executes fixed position maintenance control of the ship 1, the fixed position maintenance target position setting unit 1C2 sets, as the fixed position maintenance target position TP2 (see FIG. 5(C)), a position different from the position TPX (see FIG. 5(B)) of the ship 1 at the time when the automatic navigation control of the ship 1 is stopped. In detail, the fixed position maintenance target position setting unit 1C2 sets, as the fixed position maintenance target position TP2, a position different from the position TPX of the ship 1 detected by the ship position detection unit 1D at the time when the automatic navigation stop instruction input unit 1B5 accepts input of an instruction to stop the automatic navigation control of the ship 1 by the operator of the ship 1 or the like. Therefore, in an example of a ship 1 to which the ship control device 1C of the fourth embodiment is applied, the generation of thrust of the ship 1 in a direction that resists the inertial force (gain) of the ship 1 that occurs when transitioning from automatic navigation control of the ship 1 to fixed position keeping control of the ship 1 is suppressed, while there is no need to perform complex ship speed control at the end of the automatic navigation control of the ship 1 as in the technology described in Patent Document 1, and a smooth transition from automatic navigation control of the ship 1 to fixed position keeping control of the ship 1 can be realized (in other words, the behavior of the ship 1 can be made seamless and passengers on board the ship 1 can be given a sense of security). In one example of a ship 1 to which the ship control device 1C of the fourth embodiment is applied, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C stops the generation of propulsion and thrust for the ship 1 by the actuator 1A, but in another example, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C may cause the actuator 1A to generate thrust in a direction that resists the inertial force generated by the stopping of the automatic navigation control of the ship 1.

[0041] <Fifth embodiment> A fifth embodiment of a ship, a ship control device, a ship control method, and a program according to the present invention will be described below. The boat 1 of the fifth embodiment is configured similarly to the boat 1 of the above-described first embodiment, except for the points described below. Therefore, the boat 1 of the fifth embodiment can achieve the same effects as the boat 1 of the above-described first embodiment, except for the points described below.

[0042] FIG. 6 is a diagram showing an example of a ship 1 to which a ship control device 1C according to the fifth embodiment is applied. In the example shown in Figure 6, the ship 1 is equipped with an actuator 1A, an operation unit 1B, a ship control device 1C, a ship position detection unit 1D, a bow direction detection unit 1E, a ship speed detection unit 1F, a water fall detection unit 1G, and a communication unit 1H. The actuator 1A is configured similarly to the actuator 1A shown in Figure 1. The operation unit 1B is configured similarly to the operation unit 1B shown in Figure 1. The ship control device 1C is configured similarly to the ship control device 1C shown in Figure 1. The ship position detection unit 1D is configured similarly to the ship position detection unit 1D shown in Figure 1. The bow direction detection unit 1E is configured similarly to the bow direction detection unit 1E shown in Figure 1. The ship speed detection unit 1F is configured similarly to the ship speed detection unit 1F shown in Figure 1.

[0043] The overboard detection unit 1G detects a person on board the vessel 1 (e.g., the operator of the vessel 1) falling overboard. The overboard detection unit 1G is configured in the same manner as the lanyard cord and switch described in, for example, paragraph 0002 of Japanese Patent No. 4205261. Specifically, one end of the lanyard cord is connected to a person to be detected as having fallen overboard (e.g., a person on board the vessel 1, such as the operator of the vessel 1). The other end of the lanyard cord is connected to a switch (not shown) arranged in the vessel 1. When the subject falls overboard from the boat 1, the other end of the lanyard cord comes off the switch, and the switch detects that the subject has fallen overboard. As a result, the boat control device 1C switches from a mode in which the control is performed to operate the actuator 1A based on an input operation by the operator of the boat 1 or the like received by the operation unit 1B to a mode in which the automatic navigation control of the boat 1 is performed.

[0044] The communication unit 1H communicates with the input device 2 carried by a person who is to be detected as having fallen into water by the water-fall detection unit 1G. The input device 2 includes an input device position detection unit 2A, an operation unit 2B, and a communication unit 2C. The input device position detection unit 2A detects the position of the input device 2. The input device position detection unit 2A includes, for example, a GPS device. The GPS device calculates the position coordinates of the input device 2 by receiving signals from a plurality of GPS satellites. The operation unit 2B accepts a request to start automatic navigation control of the ship 1 (more specifically, automatic navigation control of the ship 1 to bring the ship 1 closer to the input device 2) by a detected person who has fallen overboard from the ship 1 while carrying the input device 2, for example. The communication unit 2C transmits information indicating the position of the input device 2 detected by the input device position detection unit 2A to the ship 1. The communication unit 1H of the ship 1 receives the information indicating the position of the input device 2 transmitted by the communication unit 2C. The position of the input device 2 detected by the input device position detection unit 2A is used for automatic navigation control of the ship 1 by the ship control device 1C (more specifically, for setting an automatic navigation target position TP1 (see FIG. 2(B) etc.) by the ship control device 1C). Furthermore, the communication unit 2C transmits a request to start automatic navigation control of the vessel 1 (more specifically, automatic navigation control of the vessel 1 that brings the vessel 1 closer to the input device 2) received by the operation unit 2B to the vessel 1. The communication unit 1H of the vessel 1 receives the request to start automatic navigation control of the vessel 1 transmitted by the communication unit 2C.

[0045] In the example shown in Figure 6, as described above, the distance between the ship 1 and the input device 2 is calculated based on the position of the ship 1 detected by the ship position detection unit 1D and the position of the input device 2 detected by the input device position detection unit 2A, and is used for automatic navigation control of the ship 1 by the ship control device 1C (in detail, setting of the automatic navigation target position TP1 by the ship control device 1C). In another example, the ship 1 may be equipped with a distance detection unit such as a camera or radar, and the distance between the ship 1 and the input device 2 may be detected by the distance detection unit, and this may be used for automatic navigation control of the ship 1 by the ship control device 1C (in detail, for setting the automatic navigation target position TP1 by the ship control device 1C).

[0046] FIG. 7 is a diagram for explaining an example of behavior of the ship 1 in a case where the ship control device 1C according to the fifth embodiment executes automatic sailing control and then executes fixed position keeping control. In the example shown in Fig. 7, a person to be detected as having fallen into the water by the waterfall detection unit 1G (a person to be detected who is carrying the input device 2) falls into the water at position P2 (see Fig. 7(A)) from the ship 1 moving downward in Fig. 7. As a result, the input device position detection unit 2A of the input device 2 detects position P2 as the position of the input device 2. The communication unit 2C of the input device 2 transmits information indicating the position P2 of the input device 2 to the ship 1. Meanwhile, in the ship 1, the overboard detection unit 1G detects the subject falling overboard, and accordingly the mode of the ship 1 is switched to a mode in which the ship control device 1C executes automatic navigation control of the ship 1 (more specifically, automatic navigation control of the ship 1 that brings the ship 1 closer to the input device 2). The ship position detection unit 1D detects position P1 (see FIG. 7(E)) as the position of the ship 1. The ship control device 1C sets (calculates) an automatic navigation target position TP1 (see FIG. 7(C)), which is the target position for the automatic navigation control (auto-return control) of the ship 1, based on information indicating the position P2 of the input device 2 received by the communication unit 1H and the position P1 of the ship 1 detected by the ship position detection unit 1D.

[0047] In addition, in the example shown in Figure 7, the operation unit 2B of the input device 2 receives a request to start automatic navigation control of the ship 1 from a detected person who has fallen overboard from the ship 1, and the communication unit 2C of the input device 2 transmits the request to start automatic navigation control of the ship 1 to the ship 1. As a result, the vessel control device 1C starts automatic navigation control of the vessel 1 (that is, the vessel 1 starts automatic navigation), and the vessel 1 moves toward the automatic navigation target position TP1 as shown in FIG. 7(D). In another example, when the overboard detection unit 1G detects that the subject has fallen overboard, the ship control device 1C may automatically start automatic navigation control of the ship 1, without the operation unit 2B of the input device 2 having to accept a request from the subject who has fallen overboard from the ship 1 to start automatic navigation control of the ship 1.

[0048] Next, in the example shown in Fig. 7, when the ship 1 reaches the automatic navigation target position TP1 (see Fig. 7(C)) (more specifically, when the position of the ship 1 detected by the ship position detection unit 1D roughly coincides with the automatic navigation target position TP1), the ship control device 1C stops the automatic navigation control of the ship 1 (more specifically, stops the generation of propulsive force for the ship 1 by the actuator 1A). In other words, the position of the ship 1 when the automatic navigation control of the ship 1 is stopped is the automatic navigation target position TP1. On the other hand, at the time shown in Fig. 7(C), there remains an inertial force (starting speed) caused by the vessel 1 attempting to stop while moving during execution of the automatic navigation control of the vessel 1. Therefore, as shown in Fig. 7(B), the vessel 1 continues to move due to the inertial force (starting speed) of the vessel 1.

[0049] 7, the ship control device 1C monitors the speed of the ship 1. In detail, when the speed of the ship 1 detected by the ship speed detection unit 1F drops below a first threshold (that is, when it can be assumed that the movement of the ship 1 due to the inertial force (gain) of the ship 1 has ended), the fixed point maintenance target position setting unit 1C2 of the ship control device 1C sets the position of the ship 1 detected by the ship position detection unit 1D as the fixed point maintenance target position TP2 (see FIG. 7(B)), which is the target position of the ship 1 while fixed point maintenance control of the ship 1 is being executed. Furthermore, the ship control device 1C executes fixed point maintenance control of the ship 1.

[0050] FIG. 8 is a flowchart illustrating an example of a process executed in the boat 1 to which the boat control device 1C of the fifth embodiment is applied. In the example shown in Fig. 8, in step S3A, the ship control device 1C determines whether or not the subject person's fall into the water has been detected by the waterfall detection unit 1G. If the ship control device 1C determines that the subject person's fall into the water has been detected by the waterfall detection unit 1G, the process proceeds to step S3B. On the other hand, if the ship control device 1C determines that the subject person's fall into the water has not been detected by the waterfall detection unit 1G, the routine shown in Fig. 8 is terminated. In step S3B, the communication unit 1H receives from the input device 2 information indicating the position P2 of the input device 2 detected by the input device position detection unit 2A of the input device 2 (see FIG. 7(A)). Furthermore, in step S3C, the ship position detection unit 1D detects the position P1 of the ship 1 (see FIG. 7(E)). Next, in step S31, the ship control device 1C sets (calculates) an automatic navigation target position TP1 (see Figure 7 (C)), which is the target position for the automatic navigation control (auto-return control) of the ship 1, based on the information indicating the position P2 of the input device 2 received in step S3B and the position P1 of the ship 1 detected in step S3C.

[0051] Furthermore, in step S3D, the ship control device 1C determines whether the operation unit 2B of the input device 2 has received a request to start automatic navigation control of the ship 1 from the subject who has fallen overboard from the ship 1. In detail, in step S3D, the ship control device 1C determines whether the communication unit 1H has received from the input device 2 a request to start automatic navigation control of the ship 1 from the subject who has fallen overboard from the ship 1. If the operation unit 2B of the input device 2 has received a request to start automatic navigation control of the ship 1 from the subject who has fallen overboard from the ship 1 (in other words, if the communication unit 1H has received from the input device 2 a request to start automatic navigation control of the ship 1 from the subject who has fallen overboard from the ship 1), the process proceeds to step S32. On the other hand, if the operation unit 2B of the input device 2 does not accept a request to start automatic navigation control of the vessel 1 by a detected person who has fallen overboard from the vessel 1 (i.e., if the communication unit 1H has not received a request to start automatic navigation control of the vessel 1 by a detected person who has fallen overboard from the vessel 1 from the input device 2), the routine shown in Figure 8 is terminated. As described above, in another example, when it is determined in step S3A that the person to be detected has fallen overboard by the person-overboard detection unit 1G, the process may proceed to step S32 without the communication unit 1H needing to receive from the input device 2 a request to start automatic navigation control of the ship 1 due to the person to be detected having fallen overboard from the ship 1.

[0052] In the example shown in Figure 8, in step S32, the vessel control device 1C starts automatic navigation control of the vessel 1 (i.e., the vessel 1 starts automatic navigation), and the vessel 1 moves toward the automatic navigation target position TP1, as shown in Figure 7 (D). Next, in step S33, the ship control device 1C determines whether or not to stop the automatic navigation control of the ship 1. If the ship control device 1C determines not to stop the automatic navigation control of the ship 1 (more specifically, if the position of the ship 1 detected by the ship position detection unit 1D does not approximately match the automatic navigation target position TP1 (see FIG. 7(C)) (i.e., the ship 1 has not reached the automatic navigation target position TP1) and the operation unit 2B of the input device 2 has not received an input of an instruction to stop the automatic navigation control of the ship 1 from a detected person who has fallen overboard from the ship 1), step S33 is repeatedly executed. On the other hand, if the ship control device 1C determines that the automatic navigation control of the ship 1 should be stopped (more specifically, if the position of the ship 1 detected by the ship position detection unit 1D roughly coincides with the automatic navigation target position TP1 (i.e., if the ship 1 has reached the automatic navigation target position TP1), or if the operation unit 2B of the input device 2 receives an input of an instruction to stop the automatic navigation control of the ship 1 from a detected person who has fallen overboard from the ship 1), the process proceeds to step S34.

[0053] In step S34, the vessel control device 1C monitors the speed of the vessel 1. More specifically, in step S34, the vessel control device 1C determines whether the speed of the vessel 1 detected by the vessel speed detection unit 1F has decreased to a first threshold value or less. If the speed of the vessel 1 has not decreased to a first threshold value or less (i.e., the vessel 1 continues to move due to the inertial force (gait) of the vessel 1), step S34 is repeatedly executed. On the other hand, if the speed of the vessel 1 has decreased to a first threshold value or less (i.e., it can be estimated that the movement of the vessel 1 due to the inertial force (gait) of the vessel 1 has ended), the process proceeds to step S35.

[0054] In step S35, the fixed point maintenance target position setting unit 1C2 sets the position of the ship 1 detected by the ship position detection unit 1D as the fixed point maintenance target position TP2 (see Figure 7 (B)), which is the target position of the ship 1 while fixed point maintenance control of the ship 1 is being executed. Next, in step S36, the vessel control device 1C starts the fixed position keeping control of the vessel 1. Next, in step S37, the ship control device 1C determines whether or not to stop the fixed position maintenance control of the ship 1. If the ship control device 1C determines not to stop the fixed position maintenance control of the ship 1 (more specifically, if the communication unit 1H has not received from the input device 2 a request to stop the fixed position maintenance control of the ship 1 due to a subject who has fallen overboard from the ship 1), step S37 is repeatedly executed. On the other hand, if the ship control device 1C determines to stop the fixed position maintenance control of the ship 1 (more specifically, if the communication unit 1H has received from the input device 2 a request to stop the fixed position maintenance control of the ship 1 due to a subject who has fallen overboard from the ship 1), the process proceeds to step S38. In step S38, the ship control device 1C stops the fixed position holding control of the ship 1 and stops generating thrust for the ship 1 by the actuator 1A (more specifically, thrust for the ship 1 to hold the ship 1 at the fixed position holding target position TP2 (see Figure 7(B)) against external disturbances such as wind and currents).

[0055] That is, in the example shown in Figures 6 to 8, when the ship control device 1C performs automatic navigation control of the ship 1 and then performs fixed point maintenance control of the ship 1, the fixed point maintenance target position setting unit 1C2 sets a position different from the position of the ship 1 when the automatic navigation control of the ship 1 is stopped (in the example shown in Figure 7, the automatic navigation target position TP1) as the fixed point maintenance target position TP2 (see Figure 7(B)). Therefore, in the example shown in Figures 6 to 8, the generation of thrust of the ship 1 in a direction that resists the inertial force (speed) of the ship 1 that occurs when transitioning from the automatic navigation control of the ship 1 to the fixed position keeping control of the ship 1 is suppressed, while there is no need to perform complex ship speed control at the end of the automatic navigation control of the ship 1 as in the technology described in Patent Document 1, and a smooth transition from the automatic navigation control of the ship 1 to the fixed position keeping control of the ship 1 can be realized (in other words, the behavior of the ship 1 can be made seamless, and a sense of security can be given to a detected person who has fallen overboard from the ship 1). In the example shown in Figures 6 to 8, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C stops the generation of propulsion and thrust for the ship 1 by the actuator 1A. However, in other examples, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C may cause the actuator 1A to generate thrust in a direction that resists the inertial force generated by the stopping of the automatic navigation control of the ship 1.

[0056] Sixth embodiment A sixth embodiment of the ship, the ship control device, the ship control method, and the program of the present invention will be described below. The boat 1 of the sixth embodiment is configured similarly to the boat 1 of the fifth embodiment described above, except for the points described below. Therefore, the boat 1 of the sixth embodiment can achieve the same effects as the boat 1 of the fifth embodiment described above, except for the points described below.

[0057] The ship 1 to which the ship control device 1C of the sixth embodiment is applied has the same configuration as the ship 1 to which the ship control device 1C of the fifth embodiment shown in FIG.

[0058] FIG. 9 is a flowchart illustrating an example of a process executed in the boat 1 to which the boat control device 1C of the sixth embodiment is applied. In the example shown in Fig. 9, in step S4A, the ship control device 1C determines whether or not the subject person's fall into the water has been detected by the waterfall detection unit 1G, similar to step S3A in Fig. 8. If the ship control device 1C determines that the subject person's fall into the water has been detected by the waterfall detection unit 1G, the process proceeds to step S4B. On the other hand, if the ship control device 1C determines that the subject person's fall into the water has not been detected by the waterfall detection unit 1G, the routine shown in Fig. 9 is terminated. In step S4B, the communication unit 1H receives, from the input device 2, information indicating the position P2 (see FIG. 7(A)) of the input device 2 detected by the input device position detection unit 2A of the input device 2, similar to step S3B in FIG. Furthermore, in step S4C, the ship position detection unit 1D detects the position P1 (see FIG. 7(E)) of the ship 1, similarly to step S3C in FIG. Next, in step S41, the ship control device 1C, similar to step S31 in Figure 8, sets (calculates) an automatic navigation target position TP1 (see Figure 7 (C)), which is the target position for the automatic navigation control (auto-return control) of the ship 1, based on the information indicating the position P2 of the input device 2 received in step S4B and the position P1 of the ship 1 detected in step S4C.

[0059] 8, the vessel control device 1C determines whether the operation unit 2B of the input device 2 has received a request to start automatic navigation control of the vessel 1 from the subject who has fallen overboard. If the operation unit 2B of the input device 2 has received a request to start automatic navigation control of the vessel 1 from the subject who has fallen overboard, the process proceeds to step S42. On the other hand, if the operation unit 2B of the input device 2 has not received a request to start automatic navigation control of the vessel 1 from the subject who has fallen overboard, the process ends the routine shown in FIG. As described above, in another example, when it is determined in step S4A that the person to be detected has fallen overboard by the person-overboard detection unit 1G, the process may proceed to step S42 without the communication unit 1H needing to receive from the input device 2 a request to start automatic navigation control of the ship 1 due to the person to be detected having fallen overboard from the ship 1.

[0060] In the example shown in Figure 9, in step S42, the ship control device 1C starts automatic navigation control of the ship 1, similar to step S32 in Figure 8 (i.e., the ship 1 starts automatic navigation), and the ship 1 moves toward the automatic navigation target position TP1, as shown in Figure 7 (D). Next, in step S43, the ship control device 1C determines whether or not to stop the automatic navigation control of the ship 1, similarly to step S33 in Fig. 8. If the ship control device 1C determines not to stop the automatic navigation control of the ship 1 (more specifically, if the position of the ship 1 detected by the ship position detection unit 1D does not approximately match the automatic navigation target position TP1 (see Fig. 7(C)) (i.e., if the ship 1 has not reached the automatic navigation target position TP1) and the operation unit 2B of the input device 2 has not received an input of an instruction to stop the automatic navigation control of the ship 1 from a detected person who has fallen overboard from the ship 1), step S43 is repeatedly executed. On the other hand, if the ship control device 1C determines that the automatic navigation control of the ship 1 should be stopped (more specifically, if the position of the ship 1 detected by the ship position detection unit 1D roughly coincides with the automatic navigation target position TP1 (i.e., if the ship 1 has reached the automatic navigation target position TP1), or if the operation unit 2B of the input device 2 receives an input of an instruction to stop the automatic navigation control of the ship 1 from a detected person who has fallen overboard from the ship 1), the process proceeds to step S44.

[0061] In step S44, the ship control device 1C monitors the elapsed time since the automatic navigation control of the ship 1 was stopped. In detail, in step S44, the ship control device 1C determines whether the elapsed time since the automatic navigation control of the ship 1 was stopped is equal to or greater than a second threshold value. If the elapsed time is not equal to or greater than the second threshold value (i.e., it can be assumed that the ship 1 is continuing to move due to the inertial force (gait) of the ship 1), step S44 is repeatedly executed. On the other hand, if the elapsed time is equal to or greater than the second threshold value (i.e., it can be assumed that the movement of the ship 1 due to the inertial force (gait) of the ship 1 has ended), the process proceeds to step S45.

[0062] In step S45, the fixed point holding target position setting unit 1C2, similar to step S35 in Figure 8, sets the position of the ship 1 detected by the ship position detection unit 1D as the fixed point holding target position TP2 (see Figure 7 (B)), which is the target position of the ship 1 while fixed point holding control of the ship 1 is being executed. Next, in step S46, the vessel controlling device 1C starts fixed position maintenance control of the vessel 1, similarly to step S36 in FIG. Next, in step S47, the ship control device 1C determines whether or not to stop the fixed position maintenance control of the ship 1, similar to step S37 in Fig. 8. If the ship control device 1C determines not to stop the fixed position maintenance control of the ship 1, step S47 is repeatedly executed. On the other hand, if the ship control device 1C determines to stop the fixed position maintenance control of the ship 1, the process proceeds to step S48. In step S48, the ship control device 1C stops the fixed position holding control of the ship 1, similar to step S38 in Figure 8, and stops the generation of thrust for the ship 1 by the actuator 1A (more specifically, thrust for the ship 1 to hold the ship 1 at the fixed position holding target position TP2 (see Figure 7 (B)) against external disturbances such as wind and currents).

[0063] That is, in the examples shown in Figures 6 and 9, when the ship control device 1C performs automatic navigation control of the ship 1 and then performs fixed point maintenance control of the ship 1, the fixed point maintenance target position setting unit 1C2 sets a position different from the position of the ship 1 when the automatic navigation control of the ship 1 is stopped (in the example shown in Figure 7, the automatic navigation target position TP1) as the fixed point maintenance target position TP2 (see Figure 7(B)). Therefore, in the example shown in Figures 6 and 9, the generation of thrust of the ship 1 in a direction that resists the inertial force (speed) of the ship 1 that occurs when transitioning from the automatic navigation control of the ship 1 to the fixed position keeping control of the ship 1 is suppressed, while there is no need to perform complex ship speed control at the end of the automatic navigation control of the ship 1 as in the technology described in Patent Document 1, and a smooth transition from the automatic navigation control of the ship 1 to the fixed position keeping control of the ship 1 can be realized (in other words, the behavior of the ship 1 can be made seamless, and a sense of security can be given to a detected person who has fallen overboard from the ship 1). In the examples shown in Figures 6 and 9, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C stops the generation of propulsion and thrust for the ship 1 by the actuator 1A, but in other examples, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C may cause the actuator 1A to generate thrust in a direction that resists the inertial force generated by the stopping of the automatic navigation control of the ship 1.

[0064] Seventh embodiment A ship, a ship control device, a ship control method, and a program according to a seventh embodiment of the present invention will be described below. The boat 1 of the seventh embodiment is configured similarly to the boat 1 of the above-described first embodiment, except for the points described below. Therefore, the boat 1 of the seventh embodiment can achieve the same effects as the boat 1 of the above-described first embodiment, except for the points described below.

[0065] FIG. 10 is a diagram showing an example of a ship 1 to which a ship control device 1C according to the seventh embodiment is applied. In the example shown in FIG. 10, the ship 1 includes an actuator 1A, an operation unit 1B, a ship control device 1C, a ship position detection unit 1D, a bow direction detection unit 1E, a ship speed detection unit 1F, and a communication unit 1H. The actuator 1A is configured similarly to the actuator 1A shown in Figure 1. The operation unit 1B is configured similarly to the operation unit 1B shown in Figure 1. The ship control device 1C is configured similarly to the ship control device 1C shown in Figure 1. The ship position detection unit 1D is configured similarly to the ship position detection unit 1D shown in Figure 1. The bow direction detection unit 1E is configured similarly to the bow direction detection unit 1E shown in Figure 1. The ship speed detection unit 1F is configured similarly to the ship speed detection unit 1F shown in Figure 1.

[0066] The communication unit 1H communicates with an input device 2 carried by an operator outside the ship 1 (for example, an operator of the ship 1 who is on a pier or the like). The input device 2 includes an input device position detection unit 2A, an operation unit 2B, and a communication unit 2C. The input device position detection unit 2A detects the position of the input device 2. The input device position detection unit 2A includes, for example, a GPS device. The GPS device calculates the position coordinates of the input device 2 by receiving signals from a plurality of GPS satellites. The operation unit 2B accepts, for example, a request to start automatic navigation control of the vessel 1 (more specifically, automatic navigation control of the vessel 1 to bring the vessel 1 closer to the input device 2) by a vessel operator outside the vessel 1 who is carrying the input device 2. The communication unit 2C transmits information indicating the position of the input device 2 detected by the input device position detection unit 2A to the ship 1. The communication unit 1H of the ship 1 receives the information indicating the position of the input device 2 transmitted by the communication unit 2C. The position of the input device 2 detected by the input device position detection unit 2A is used for automatic navigation control of the ship 1 by the ship control device 1C (more specifically, for setting an automatic navigation target position TP1 (see FIG. 2(B) etc.) by the ship control device 1C). Furthermore, the communication unit 2C transmits a request to start automatic navigation control of the vessel 1 (more specifically, automatic navigation control of the vessel 1 that brings the vessel 1 closer to the input device 2) received by the operation unit 2B to the vessel 1. The communication unit 1H of the vessel 1 receives the request to start automatic navigation control of the vessel 1 transmitted by the communication unit 2C.

[0067] In the example shown in Figure 10, the distance between the ship 1 and the input device 2 is calculated based on the position of the ship 1 detected by the ship position detection unit 1D and the position of the input device 2 detected by the input device position detection unit 2A, and is used for automatic navigation control of the ship 1 by the ship control device 1C (in detail, setting of the automatic navigation target position TP1 by the ship control device 1C). In another example, the ship 1 may be equipped with a distance detection unit such as a camera or radar, and the distance between the ship 1 and the input device 2 may be detected by the distance detection unit, and this may be used for automatic navigation control of the ship 1 by the ship control device 1C (in detail, for setting the automatic navigation target position TP1 by the ship control device 1C).

[0068] FIG. 11 is a flowchart illustrating an example of a process executed in the boat 1 to which the boat control device 1C of the seventh embodiment is applied. In the example shown in FIG. 11, in step S5A, the ship control device 1C determines whether the operation unit 2B of the input device 2 has accepted a request to start automatic sailing control of the ship 1 from a ship operator other than the ship 1. If the operation unit 2B of the input device 2 has accepted a request to start automatic sailing control of the ship 1 from a ship operator other than the ship 1 (i.e., if the communication unit 1H has received from the input device 2 a request to start automatic sailing control of the ship 1 from a ship operator other than the ship 1), the process proceeds to step S5B. On the other hand, if the operation unit 2B of the input device 2 has not accepted a request to start automatic sailing control of the ship 1 from a ship operator other than the ship 1 (i.e., if the communication unit 1H has not received from the input device 2 a request to start automatic sailing control of the ship 1 from a ship operator other than the ship 1), the routine shown in FIG. 11 is terminated. In step S5B, the communication unit 1H receives from the input device 2 information indicating the position of the input device 2 detected by the input device position detection unit 2A of the input device 2. In addition, in step S5C, the ship position detection unit 1D detects the position of the ship 1. Next, in step S51, the vessel control device 1C sets (calculates) an automatic navigation target position, which is a target position for automatic navigation control of the vessel 1, based on the information indicating the position of the input device 2 received in step S5B and the position of the vessel 1 detected in step S5C. Then, the process proceeds to step S52.

[0069] In step S52, the vessel control device 1C starts the automatic navigation control of the vessel 1 (that is, the vessel 1 starts automatic navigation), and the vessel 1 moves toward the automatic navigation target position. Next, in step S53, the ship control device 1C judges whether or not to stop the automatic navigation control of the ship 1. When the ship control device 1C judges not to stop the automatic navigation control of the ship 1 (in detail, when the position of the ship 1 detected by the ship position detection unit 1D does not approximately match the automatic navigation target position (i.e., when the ship 1 has not reached the automatic navigation target position) and the operation unit 2B of the input device 2 has not received an input of an instruction to stop the automatic navigation control of the ship 1 from the operator outside the ship 1), step S53 is repeatedly executed. On the other hand, when the ship control device 1C judges to stop the automatic navigation control of the ship 1 (in detail, when the position of the ship 1 detected by the ship position detection unit 1D approximately matches the automatic navigation target position (i.e., when the ship 1 has reached the automatic navigation target position) or when the operation unit 2B of the input device 2 has received an input of an instruction to stop the automatic navigation control of the ship 1 from the operator outside the ship 1), the process proceeds to step S54.

[0070] In step S54, the vessel control device 1C monitors the speed of the vessel 1. More specifically, in step S54, the vessel control device 1C determines whether the speed of the vessel 1 detected by the vessel speed detection unit 1F has decreased to a first threshold value or less. If the speed of the vessel 1 has not decreased to a first threshold value or less (i.e., the vessel 1 continues to move due to the inertial force (gait) of the vessel 1), step S54 is repeatedly executed. On the other hand, if the speed of the vessel 1 has decreased to a first threshold value or less (i.e., it can be estimated that the movement of the vessel 1 due to the inertial force (gait) of the vessel 1 has ended), the process proceeds to step S55.

[0071] In step S55, the fixed position keeping target position setting unit 1C2 sets the position of the ship 1 detected by the ship position detection unit 1D as a fixed position keeping target position, which is the target position of the ship 1 while the fixed position keeping control of the ship 1 is being executed. Next, in step S56, the vessel control device 1C starts the fixed position keeping control of the vessel 1. Next, in step S57, the ship control device 1C determines whether or not to stop the fixed position holding control of the ship 1. If the ship control device 1C determines not to stop the fixed position holding control of the ship 1 (more specifically, if the communication unit 1H has not received from the input device 2 a request from an operator outside the ship 1 to stop the fixed position holding control of the ship 1), step S57 is repeatedly executed. On the other hand, if the ship control device 1C determines to stop the fixed position holding control of the ship 1 (more specifically, if the communication unit 1H has received from the input device 2 a request from an operator outside the ship 1 to stop the fixed position holding control of the ship 1), the process proceeds to step S58. In step S58, the ship control device 1C stops the fixed position holding control of the ship 1 and stops the generation of thrust for the ship 1 by the actuator 1A (more specifically, thrust for the ship 1 to hold the ship 1 at a fixed position holding target position against external disturbances such as wind and currents).

[0072] That is, in the example shown in Figures 10 and 11, when the ship control device 1C performs automatic navigation control of the ship 1 and then performs fixed point maintenance control of the ship 1, the fixed point maintenance target position setting unit 1C2 sets a position different from the position of the ship 1 when the automatic navigation control of the ship 1 is stopped as the fixed point maintenance target position. Therefore, in the example shown in Figures 10 and 11, the generation of thrust of the ship 1 in a direction that resists the inertial force (gain) of the ship 1 that occurs when transitioning from automatic navigation control of the ship 1 to fixed position keeping control of the ship 1 is suppressed, while there is no need to perform complex ship speed control at the end of the automatic navigation control of the ship 1 as in the technology described in Patent Document 1, and a smooth transition from automatic navigation control of the ship 1 to fixed position keeping control of the ship 1 can be realized (in other words, the behavior of the ship 1 can be made seamless). In the example shown in Figures 10 and 11, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C stops the generation of propulsion and thrust for the ship 1 by the actuator 1A, but in other examples, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C may cause the actuator 1A to generate thrust in a direction that resists the inertial force generated by the stopping of the automatic navigation control of the ship 1.

[0073] In another example of the processing executed in the ship 1 or the like to which the ship control device 1C of the seventh embodiment is applied, processing similar to the processing shown in FIG. 3 described above is executed. 3, the operation unit 2B of the input device 2 accepts setting of an automatic navigation target position TP1 (see FIG. 2(B)), which is a target position for automatic navigation control of the ship 1, by an operator outside the ship 1. The communication unit 2C of the input device 2 transmits information indicating the automatic navigation target position TP1 to the ship 1. Next, in step S12, the operation unit 2B of the input device 2 accepts input of an instruction to start automatic navigation control of the ship 1 from an operator outside the ship 1. The communication unit 2C of the input device 2 transmits the instruction to start automatic navigation control of the ship 1 to the ship 1. As a result, the ship control device 1C starts automatic navigation control of the ship 1 (i.e., the ship 1 starts automatic navigation), and the ship 1 moves toward the automatic navigation target position TP1, as shown in FIG. 2(A). Next, in step S13, the ship control device 1C judges whether or not to stop the automatic navigation control of the ship 1. When the ship control device 1C judges not to stop the automatic navigation control of the ship 1 (in detail, when the position of the ship 1 detected by the ship position detection unit 1D does not approximately match the automatic navigation target position TP1 (i.e., when the ship 1 has not reached the automatic navigation target position TP1) and the operation unit 2B of the input device 2 has not received an input of an instruction to stop the automatic navigation control of the ship 1 from the operator outside the ship 1), step S13 is repeatedly executed. On the other hand, when the ship control device 1C judges to stop the automatic navigation control of the ship 1 (in detail, when the position of the ship 1 detected by the ship position detection unit 1D approximately matches the automatic navigation target position TP1 (i.e., when the ship 1 has reached the automatic navigation target position TP1) or when the operation unit 2B of the input device 2 has received an input of an instruction to stop the automatic navigation control of the ship 1 from the operator outside the ship 1), the process proceeds to step S14.

[0074] In step S14, the vessel control device 1C monitors the speed of the vessel 1. More specifically, in step S14, the vessel control device 1C determines whether the speed of the vessel 1 detected by the vessel speed detection unit 1F has decreased to a first threshold value or less. If the speed of the vessel 1 has not decreased to a first threshold value or less (i.e., the vessel 1 continues to move due to the inertial force (gait) of the vessel 1), step S14 is repeatedly executed. On the other hand, if the speed of the vessel 1 has decreased to a first threshold value or less (i.e., it can be estimated that the movement of the vessel 1 due to the inertial force (gait) of the vessel 1 has ended), the process proceeds to step S15.

[0075] In step S15, the fixed point keeping target position setting unit 1C2 sets the position of the ship 1 detected by the ship position detection unit 1D as the fixed point keeping target position TP2 (see Figure 2 (C)), which is the target position of the ship 1 while fixed point keeping control of the ship 1 is being executed. Next, in step S16, the vessel control device 1C starts the fixed position keeping control of the vessel 1. Next, in step S17, the ship control device 1C determines whether or not to stop the fixed position holding control of the ship 1. If the ship control device 1C determines not to stop the fixed position holding control of the ship 1 (more specifically, if the operation unit 2B of the input device 2 has not received an input of an instruction to stop the fixed position holding control of the ship 1 from an operator outside the ship 1), step S17 is repeatedly executed. On the other hand, if the ship control device 1C determines to stop the fixed position holding control of the ship 1 (more specifically, if the operation unit 2B of the input device 2 has received an input of an instruction to stop the fixed position holding control of the ship 1 from an operator outside the ship 1), the process proceeds to step S18. In step S18, the ship control device 1C stops the fixed position holding control of the ship 1 and stops generating the propulsion force of the ship 1 by the actuator 1A (more specifically, the thrust of the ship 1 for holding the ship 1 at the fixed position holding target position TP2 (see Figure 2 (D)) against external disturbances such as wind and currents).

[0076] Eighth embodiment An eighth embodiment of a ship, a ship control device, a ship control method, and a program according to the present invention will now be described. The boat 1 of the eighth embodiment is configured similarly to the boat 1 of the seventh embodiment described above, except for the points described below. Therefore, the boat 1 of the eighth embodiment can achieve the same effects as the boat 1 of the seventh embodiment described above, except for the points described below.

[0077] The ship 1 to which the ship control device 1C of the eighth embodiment is applied has the same configuration as the ship 1 to which the ship control device 1C of the seventh embodiment shown in FIG. 10 is applied.

[0078] FIG. 12 is a flowchart illustrating an example of a process executed in the boat 1 to which the boat control device 1C of the eighth embodiment is applied. In the example shown in FIG. 12, in step S6A, the ship control device 1C determines whether or not the operation unit 2B of the input device 2 has accepted a request to start automatic sailing control of the ship 1 from a ship operator other than the ship 1, similar to step S5A in FIG. 11. If the operation unit 2B of the input device 2 has accepted a request to start automatic sailing control of the ship 1 from a ship operator other than the ship 1 (i.e., if the communication unit 1H has received from the input device 2 a request to start automatic sailing control of the ship 1 from a ship operator other than the ship 1), the process proceeds to step S6B. On the other hand, if the operation unit 2B of the input device 2 has not accepted a request to start automatic sailing control of the ship 1 from a ship operator other than the ship 1 (i.e., if the communication unit 1H has not received from the input device 2 a request to start automatic sailing control of the ship 1 from a ship operator other than the ship 1), the process ends the routine shown in FIG. 12. In step S6B, the communication unit 1H receives, from the input device 2, information indicating the position of the input device 2 detected by the input device position detection unit 2A of the input device 2, similarly to step S5B in FIG. Furthermore, in step S6C, the vessel position detection unit 1D detects the position of the vessel 1 in the same manner as in step S5C of FIG. 11, the vessel control device 1C sets (calculates) an automatic navigation target position, which is a target position for automatic navigation control of the vessel 1, based on the information indicating the position of the input device 2 received in step S6B and the position of the vessel 1 detected in step S6C. Then, the process proceeds to step S62.

[0079] In step S62, similarly to step S52 in FIG. 11, the vessel control device 1C starts the automatic navigation control of the vessel 1 (that is, the vessel 1 starts automatic navigation), and the vessel 1 moves toward the automatic navigation target position. Next, in step S63, the ship control device 1C determines whether or not to stop the automatic navigation control of the ship 1, similarly to step S53 in Fig. 11. When the ship control device 1C determines not to stop the automatic navigation control of the ship 1 (in detail, when the position of the ship 1 detected by the ship position detection unit 1D does not approximately match the automatic navigation target position (i.e., when the ship 1 has not reached the automatic navigation target position) and the operation unit 2B of the input device 2 has not received an input of an instruction to stop the automatic navigation control of the ship 1 by the operator outside the ship 1), step S63 is repeatedly executed. On the other hand, when the ship control device 1C determines to stop the automatic navigation control of the ship 1 (in detail, when the position of the ship 1 detected by the ship position detection unit 1D approximately matches the automatic navigation target position (i.e., when the ship 1 has reached the automatic navigation target position) or when the operation unit 2B of the input device 2 has received an input of an instruction to stop the automatic navigation control of the ship 1 by the operator outside the ship 1), the process proceeds to step S64.

[0080] In step S64, the ship control device 1C monitors the elapsed time since the automatic navigation control of the ship 1 was stopped. More specifically, in step S64, the ship control device 1C determines whether the elapsed time since the automatic navigation control of the ship 1 was stopped is equal to or greater than a second threshold value. If the elapsed time is not equal to or greater than the second threshold value (i.e., it can be assumed that the ship 1 is continuing to move due to the inertial force (gait) of the ship 1), step S64 is repeatedly executed. On the other hand, if the elapsed time is equal to or greater than the second threshold value (i.e., it can be assumed that the movement of the ship 1 due to the inertial force (gait) of the ship 1 has ended), the process proceeds to step S65.

[0081] In step S65, the fixed point maintenance target position setting unit 1C2, similar to step S55 in Figure 11, sets the position of the ship 1 detected by the ship position detection unit 1D as the fixed point maintenance target position, which is the target position of the ship 1 while fixed point maintenance control of the ship 1 is being executed. Next, in step S66, the vessel controlling device 1C starts fixed position maintenance control of the vessel 1, similarly to step S56 in FIG. Next, in step S67, the ship controlling device 1C determines whether or not to stop the fixed position maintenance control of the ship 1, similar to step S57 in Fig. 11. If the ship controlling device 1C determines not to stop the fixed position maintenance control of the ship 1, step S67 is repeatedly executed. On the other hand, if the ship controlling device 1C determines to stop the fixed position maintenance control of the ship 1, the process proceeds to step S68. In step S68, the ship control device 1C stops the fixed position holding control of the ship 1, as in step S58 of Figure 11, and stops the generation of thrust for the ship 1 by the actuator 1A (more specifically, thrust for the ship 1 to hold the ship 1 at a fixed position holding target position against external disturbances such as wind and currents).

[0082] That is, in the example shown in Figures 10 and 12, when the ship control device 1C performs automatic navigation control of the ship 1 and then performs fixed point maintenance control of the ship 1, the fixed point maintenance target position setting unit 1C2 sets a position different from the position of the ship 1 when the automatic navigation control of the ship 1 is stopped as the fixed point maintenance target position. Therefore, in the example shown in Figures 10 and 12, the generation of thrust of the ship 1 in a direction that resists the inertial force (gain) of the ship 1 that occurs when transitioning from automatic navigation control of the ship 1 to fixed position keeping control of the ship 1 is suppressed, while there is no need to perform complex ship speed control at the end of the automatic navigation control of the ship 1 as in the technology described in Patent Document 1, and a smooth transition from automatic navigation control of the ship 1 to fixed position keeping control of the ship 1 can be realized (in other words, the behavior of the ship 1 can be made seamless). In the example shown in Figures 10 and 12, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C stops the generation of propulsion and thrust for the ship 1 by the actuator 1A, but in other examples, when the automatic navigation control of the ship 1 is stopped, the ship control device 1C may cause the actuator 1A to generate thrust in a direction that resists the inertial force generated by the stopping of the automatic navigation control of the ship 1.

[0083] In another example of the processing executed in the ship 1 or the like to which the ship control device 1C of the eighth embodiment is applied, processing similar to the processing shown in FIG. 4 described above is executed. 4, the operation unit 2B of the input device 2 accepts setting of an automatic navigation target position TP1 (see FIG. 2(B)), which is a target position for automatic navigation control of the ship 1, by an operator outside the ship 1. The communication unit 2C of the input device 2 transmits information indicating the automatic navigation target position TP1 to the ship 1. Next, in step S22, the operation unit 2B of the input device 2 accepts input of an instruction to start automatic navigation control of the ship 1 from an operator outside the ship 1. The communication unit 2C of the input device 2 transmits the instruction to start automatic navigation control of the ship 1 to the ship 1. As a result, the ship control device 1C starts automatic navigation control of the ship 1 (i.e., the ship 1 starts automatic navigation), and the ship 1 moves toward the automatic navigation target position TP1 as shown in FIG. 2(A). Next, in step S23, the ship control device 1C determines whether or not to stop the automatic navigation control of the ship 1. If the ship control device 1C determines not to stop the automatic navigation control of the ship 1, step S23 is repeatedly executed. On the other hand, if the ship control device 1C determines to stop the automatic navigation control of the ship 1, the process proceeds to step S24.

[0084] In step S24, the ship control device 1C monitors the elapsed time since the automatic navigation control of the ship 1 was stopped. In detail, in step S24, the ship control device 1C determines whether the elapsed time since the automatic navigation control of the ship 1 was stopped is equal to or greater than a second threshold value. If the elapsed time is not equal to or greater than the second threshold value (i.e., it can be assumed that the ship 1 is continuing to move due to the inertial force (gait) of the ship 1), step S24 is repeatedly executed. On the other hand, if the elapsed time is equal to or greater than the second threshold value (i.e., it can be assumed that the movement of the ship 1 due to the inertial force (gait) of the ship 1 has ended), the process proceeds to step S25.

[0085] In step S25, the fixed point keeping target position setting unit 1C2 sets the position of the ship 1 detected by the ship position detection unit 1D as the fixed point keeping target position TP2 (see Figure 2 (C)), which is the target position of the ship 1 while fixed point keeping control of the ship 1 is being executed. Next, in step S26, the vessel control device 1C starts the fixed position keeping control of the vessel 1. Next, in step S27, the ship control device 1C determines whether or not to stop the fixed position holding control of the ship 1. If the ship control device 1C determines not to stop the fixed position holding control of the ship 1 (more specifically, if the operation unit 2B of the input device 2 has not received an input of an instruction to stop the fixed position holding control of the ship 1 from an operator outside the ship 1), step S27 is repeatedly executed. On the other hand, if the ship control device 1C determines to stop the fixed position holding control of the ship 1 (more specifically, if the operation unit 2B of the input device 2 has received an input of an instruction to stop the fixed position holding control of the ship 1 from an operator outside the ship 1), the process proceeds to step S28. In step S28, the vessel control device 1C stops the fixed position maintenance control of the vessel 1, and stops the generation of thrust for the vessel 1 by the actuator 1A.

[0086] Although the present invention has been described above using the embodiments, the present invention is not limited to these embodiments, and various modifications and substitutions can be made without departing from the scope of the present invention. The configurations described in the above-mentioned embodiments and examples may be combined.

[0087] Note that all or part of the functions of each unit of the boat 1 in the above-described embodiment may be realized by recording a program for realizing these functions on a computer-readable recording medium, and reading and executing the program recorded on the recording medium into a computer system. Note that the term "computer system" here includes hardware such as an OS and peripheral devices. In addition, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage units such as hard disks built into computer systems. Furthermore, the term "computer-readable recording medium" may also include those that dynamically hold a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and those that hold a program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or client in such cases. Furthermore, the above program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system. [Explanation of symbols]

[0088] 1...ship, 1A...actuator, 1A1...rudder section, 1A2...thrust generation section, 1B...operation section, 1B1...steering section, 1B2...throttle operation section, 1B3...automatic navigation target position setting section, 1B4...automatic navigation start instruction input section, 1B5...automatic navigation stop instruction input section, 1C...ship control device, 1C1...actuator control section, 1C2...fixed point holding target position setting section, 1D...ship position detection section, 1E...bow direction detection section, 1F...ship speed detection section, 1G...overboard detection section, 1H...communication section, 2...input device, 2A...input device position detection section, 2B...operation section, 2C...communication section

Claims

1. an actuator having a function of generating a propulsive force for a vessel and a function of generating a moment on the vessel; a vessel control device that operates the actuator, The vessel control device is capable of executing automatic navigation control of the vessel and fixed position keeping control of the vessel, The vessel control device includes a fixed position maintenance target position setting unit that sets a fixed position maintenance target position that is a target position of the vessel during execution of fixed position maintenance control of the vessel, When the ship control device executes automatic navigation control of the ship and then executes fixed position keeping control of the ship, the fixed point maintenance target position setting unit sets, at a time when it can be estimated that the movement of the ship due to the speed of the ship has ended after the automatic navigation control is stopped, a position different from an automatic navigation stop position which is the position of the ship when the automatic navigation control of the ship is stopped, and a position where it can be estimated that the movement of the ship due to the speed of the ship has ended, as the fixed point maintenance target position; ship.

2. A ship position detection unit for detecting the position of the ship; a vessel speed detection unit for detecting a vessel speed, the vessel control device stops generation of a propulsive force for the vessel by the actuator when the automatic vessel navigation control is stopped, or causes the actuator to generate a thrust in a direction against an inertial force generated by the stopping of the automatic vessel navigation control, the fixed point maintenance target position setting unit sets the position of the ship detected by the ship position detection unit as the fixed point maintenance target position when the speed of the ship detected by the ship speed detection unit drops to a first threshold value or less; 2. The watercraft of claim 1.

3. a ship position detection unit for detecting the position of the ship; the vessel control device stops generation of a propulsive force for the vessel by the actuator when the automatic vessel navigation control is stopped, or causes the actuator to generate a thrust in a direction against an inertial force generated by the stopping of the automatic vessel navigation control, the fixed-point maintenance target position setting unit sets the position of the ship detected by the ship position detection unit as the fixed-point maintenance target position when an elapsed time from when the automatic navigation control of the ship was stopped becomes equal to or greater than a second threshold value.

2. The watercraft of claim 1.

4. an automatic navigation stop instruction input unit that receives an input of an instruction to stop automatic navigation of the ship; A ship position detection unit for detecting the position of the ship; a vessel speed detection unit for detecting a vessel speed, When automatic navigation control of the ship is stopped, which is when the automatic navigation stop instruction input unit receives an input of an instruction to stop automatic navigation of the ship, the ship control device stops generation of a propulsive force of the ship by the actuator, or causes the actuator to generate a thrust in a direction against an inertial force generated by the stopping of the automatic navigation control of the ship, the fixed point maintenance target position setting unit sets the position of the ship detected by the ship position detection unit as the fixed point maintenance target position when the speed of the ship detected by the ship speed detection unit drops to a first threshold value or less; 2. The watercraft of claim 1.

5. an automatic navigation stop instruction input unit that receives an input of an instruction to stop automatic navigation of the ship; A ship position detection unit for detecting the position of the ship, When automatic navigation control of the ship is stopped, which is when the automatic navigation stop instruction input unit receives an input of an instruction to stop automatic navigation of the ship, the ship control device stops generation of a propulsive force of the ship by the actuator, or causes the actuator to generate a thrust in a direction against an inertial force generated by the stopping of the automatic navigation control of the ship, the fixed-point maintenance target position setting unit sets the position of the ship detected by the ship position detection unit as the fixed-point maintenance target position when the elapsed time from when the automatic navigation stop instruction input unit accepted the input of an instruction to stop the automatic navigation of the ship becomes equal to or greater than a second threshold value.

2. The watercraft of claim 1.

6. A ship position detection unit for detecting the position of the ship; A vessel speed detection unit for detecting a vessel speed; a water fall detection unit for detecting a water fall of a passenger of the vessel; a communication unit that communicates with an input device carried by a person to be detected as having fallen into water by the water fall detection unit; when the overboard detection unit detects that the subject has fallen overboard, the vessel control device executes automatic vessel navigation control to bring the vessel closer to the input device, and then executes fixed-position maintenance control of the vessel; the vessel control device stops generation of a propulsive force for the vessel by the actuator when the automatic vessel navigation control is stopped, or causes the actuator to generate a thrust in a direction against an inertial force generated by the stopping of the automatic vessel navigation control, the fixed point maintenance target position setting unit sets the position of the ship detected by the ship position detection unit as the fixed point maintenance target position when the speed of the ship detected by the ship speed detection unit drops to a first threshold value or less; 2. The watercraft of claim 1.

7. A ship position detection unit for detecting the position of the ship; a water fall detection unit for detecting a water fall of a passenger of the vessel; a communication unit that communicates with an input device carried by a person to be detected as having fallen into water by the water fall detection unit; when the overboard detection unit detects that the subject has fallen overboard, the vessel control device executes automatic vessel navigation control to bring the vessel closer to the input device, and then executes fixed-position maintenance control of the vessel; the vessel control device stops generation of a propulsive force for the vessel by the actuator when the automatic vessel navigation control is stopped, or causes the actuator to generate a thrust in a direction against an inertial force generated by the stopping of the automatic vessel navigation control, the fixed-point maintenance target position setting unit sets the position of the ship detected by the ship position detection unit as the fixed-point maintenance target position when an elapsed time from when the automatic navigation control of the ship was stopped becomes equal to or greater than a second threshold value.

2. The watercraft of claim 1.

8. A ship position detection unit for detecting the position of the ship; A vessel speed detection unit for detecting a vessel speed; a communication unit for communicating with an input device carried by a vessel operator outside the vessel, When the communication unit receives a request to start automatic navigation control of the ship from the input device, the ship control device executes automatic navigation control of the ship to bring the ship closer to the input device, and then executes fixed position maintenance control of the ship; the vessel control device stops generation of a propulsive force for the vessel by the actuator when the automatic vessel navigation control is stopped, or causes the actuator to generate a thrust in a direction against an inertial force generated by the stopping of the automatic vessel navigation control, the fixed point maintenance target position setting unit sets the position of the ship detected by the ship position detection unit as the fixed point maintenance target position when the speed of the ship detected by the ship speed detection unit drops to a first threshold value or less; 2. The watercraft of claim 1.

9. A ship position detection unit for detecting the position of the ship; a communication unit for communicating with an input device carried by a vessel operator outside the vessel, When the communication unit receives a request to start automatic navigation control of the ship from the input device, the ship control device executes automatic navigation control of the ship to bring the ship closer to the input device, and then executes fixed position maintenance control of the ship; the vessel control device stops generation of a propulsive force for the vessel by the actuator when the automatic vessel navigation control is stopped, or causes the actuator to generate a thrust in a direction against an inertial force generated by the stopping of the automatic vessel navigation control, the fixed-point maintenance target position setting unit sets the position of the ship detected by the ship position detection unit as the fixed-point maintenance target position when an elapsed time from when the automatic navigation control of the ship was stopped becomes equal to or greater than a second threshold value.

2. The watercraft of claim 1.

10. 1. A vessel control device that operates an actuator having a function of generating a propulsive force for a vessel and a function of generating a moment on the vessel, The vessel control device is capable of executing automatic navigation control of the vessel and fixed position keeping control of the vessel, The vessel control device includes a fixed position maintenance target position setting unit that sets a fixed position maintenance target position that is a target position of the vessel during execution of fixed position maintenance control of the vessel, When the ship control device executes automatic navigation control of the ship and then executes fixed position keeping control of the ship, the fixed point maintenance target position setting unit sets, at a time when it can be estimated that the movement of the ship due to the speed of the ship has ended after the automatic navigation control is stopped, a position different from an automatic navigation stop position which is the position of the ship when the automatic navigation control of the ship is stopped, and a position where it can be estimated that the movement of the ship due to the speed of the ship has ended, as the fixed point maintenance target position; Ship control equipment.

11. 1. A ship control method for a ship control device that operates an actuator having a function of generating a propulsive force for a ship and a function of generating a moment on the ship, comprising: an automatic navigation control step in which the ship control device executes automatic navigation control of the ship; a fixed position keeping control step in which the vessel control device executes a fixed position keeping control of the vessel; a fixed position maintenance target position setting step in which the vessel control device sets a fixed position maintenance target position which is a target position of the vessel while the vessel control device is executing a fixed position maintenance control of the vessel, When the automatic navigation control step is executed and then the fixed position maintenance control step is executed, In the fixed point maintenance target position setting step, at a time when it can be estimated that the movement of the ship due to the speed of the ship has ended after the automatic navigation control is stopped, a position different from an automatic navigation stop position which is the position of the ship when the automatic navigation control of the ship is stopped, and a position where it can be estimated that the movement of the ship due to the speed of the ship has ended is set as the fixed point maintenance target position. Ship control method.

12. A computer mounted on a vessel control device that operates an actuator having a function of generating a propulsive force for a vessel and a function of generating a moment on the vessel, an automatic navigation control step of executing automatic navigation control of the ship; a fixed position keeping control step of performing a fixed position keeping control of the ship; a fixed point maintenance target position setting step for setting a fixed point maintenance target position which is a target position of the vessel during execution of fixed point maintenance control of the vessel, When the automatic navigation control step is executed and then the fixed position maintenance control step is executed, In the fixed point maintenance target position setting step, at a time when it can be estimated that the movement of the ship due to the speed of the ship has ended after the automatic navigation control is stopped, a position different from an automatic navigation stop position which is the position of the ship when the automatic navigation control of the ship is stopped, and a position where it can be estimated that the movement of the ship due to the speed of the ship has ended is set as the fixed point maintenance target position. program.

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