Method for controlling the movement of a ship and ship

Abstract

To improve the comfort of ship crews. [Solution] The ship 10 is equipped with at least a starboard outboard motor 13a and a port outboard motor 13b at the stern 12, and performs forward and backward movement control toward the target position and turning control toward the target bearing. When the required thrust is less than the sum of the minimum thrusts of the two outboard motors 13 and greater than or equal to the minimum thrust of one outboard motor 13, thrust is generated only in one outboard motor 13 of the starboard outboard motor 13a and port outboard motor 13b that is capable of generating the thrust F necessary for the ship 10 to approach the target position and the turning moment M necessary for the ship 10's bearing to match the target bearing.

Description

Technical Field

[0001] The present invention relates to a movement control method for a ship provided with at least two propulsors, and to a ship.

Background Art

[0002] When a ship provided with propulsors on the starboard side and the port side of the stern respectively performs so-called fixed-point holding control or berthing control, it may perform both control of longitudinal movement toward a target position and control of turning toward a target azimuth.

[0003] By the way, fixed-point holding control and berthing control do not involve rapid or large movement, so the required thrust (requested thrust) is small. For example, the requested thrust determined by a BCU (Boat Control Unit) may be smaller than the sum of the minimum thrust of the starboard propulsor and the minimum thrust of the port propulsor. In this case, even if the thrust generated by the starboard propulsor and the port propulsor is set to their respective minimum thrusts, the total thrust of the respective propulsors will be larger than the requested thrust, causing the hull to move more than necessary.

[0004] Therefore, conventionally, when the requested thrust is smaller than the sum of the minimum thrust of the starboard propulsor and the minimum thrust of the port propulsor, the shift state of each propulsor is shifted to a neutral state in which the power source of each propulsor and the propeller are disconnected by a clutch, and no thrust is generated from any of the propulsors. However, if no thrust is generated from any of the propulsors, the ship becomes unable to move and cannot counteract disturbances.

[0005] In contrast, when a target engine speed is set that corresponds to an absolute value less than the lower limit speed, a technique is known in which the engine operates at the lower limit speed while the engine's rotation is intermittently transmitted to the propeller with a duty cycle corresponding to the target engine speed (see, for example, Patent Document 1). That is, in the technique of Patent Document 1, by intermittently connecting the power source of each thruster to the propeller, it is possible to generate thrust corresponding to a required thrust that is smaller than the sum of the minimum thrust of the starboard thruster and the minimum thrust of the port thruster. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 4707362 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, when the power source and propeller of each propeller are intermittently connected, the clutch between the power source and the propeller repeatedly engages and disengages, resulting in shift noise during connection and shift shock associated with the clutch engagement and disengagement. Therefore, there is room for improvement from the perspective of the comfort of the ship's crew.

[0008] The present invention aims to improve the comfort of ship crews. [Means for solving the problem]

[0009] A method for controlling the movement of a ship according to one aspect of this invention is a method for controlling the movement of a ship that is equipped with propellers on at least the starboard and port sides of the stern, and performs longitudinal movement control toward a target position and turning control toward a target bearing, wherein when the required thrust is less than the sum of the minimum thrusts of the two propellers and greater than or equal to the minimum thrust of one propeller, thrust is generated only in one of the propellers, the starboard propeller and the port propeller, which is capable of generating the movement force for the ship to approach the target position and the turning moment for the ship's bearing to coincide with the target bearing.

[0010] With this configuration, if the required thrust is less than the sum of the minimum thrusts of the two propellers but greater than or equal to the minimum thrust of one propeller, thrust is generated only by one propeller. This eliminates the need to intermittently connect the power source and propeller of each propeller to generate thrust equivalent to the required thrust. As a result, there is no shift noise when the power source and propeller are connected by clutches, nor is there any shift shock associated with connecting and disconnecting the power source and propeller by clutches. Consequently, the comfort of the ship's crew can be improved. [Effects of the Invention]

[0011] According to the present invention, the comfort of ship crew members can be improved. [Brief explanation of the drawing]

[0012] [Figure 1] This figure schematically shows the configuration of a ship according to an embodiment of the present invention. [Figure 2] This is a block diagram illustrating the configuration of the ship's propulsion system installed on the vessel shown in Figure 1. [Figure 3] This is a diagram illustrating the turning mode as a form of movement for ships. [Figure 4] This figure illustrates an example of movement control to a target line as a method for controlling the movement of a vessel according to this embodiment. [Figure 5]This figure illustrates an example of movement control to a target line as a method for controlling the movement of a vessel according to this embodiment. [Figure 6] This figure illustrates an example of movement control to a target line as a method for controlling the movement of a vessel according to this embodiment. [Figure 7] This figure illustrates an example of movement control to a target line as a method for controlling the movement of a vessel according to this embodiment. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will now be described with reference to the drawings. Figure 1 is a schematic diagram showing the configuration of a vessel according to an embodiment of the present invention, where Figure 1(A) shows the vessel viewed from the side and Figure 1(B) shows the vessel viewed from the rear.

[0014] In Figure 1, the vessel 10 is, for example, a planing boat, and comprises a hull 11 and, for example, at least two outboard motors 13 attached to the stern 12 of the hull 11 as propulsion devices. The hull 11 also has a cabin 14 that also serves as the cockpit. Although the vessel 10 in Figure 1 is assumed to be a planing boat, the vessel 10 is not limited to a planing boat and may be, for example, a relatively small displacement vessel.

[0015] The outboard motor 13 incorporates an internal combustion engine or electric motor (not shown) as a power source. The outboard motor 13 imparts thrust to the vessel 10 by a propeller 15 that is rotated by the driving force generated by the power source. In the outboard motor 13, the power source and the propeller 15 are connected via a clutch (not shown). When the outboard motor 13 is shifted to the neutral position, the clutch disconnects the power source and the propeller 15, so the outboard motor 13 does not generate thrust. On the other hand, when the outboard motor 13 is shifted to the forward or reverse position, the clutch connects the power source and the propeller 15, so the outboard motor 13 generates thrust.

[0016] Further, the outboard motor 13 is provided with a steering mechanism (not shown). The steering mechanism adjusts the acting direction of the thrust generated by the propeller 15 of the outboard motor 13 in the left-right direction by turning the outboard motor 13 relative to the hull 11 in the left-right direction of the hull 11 (hereinafter simply referred to as "left-right direction"). Hereinafter, the outboard motor 13 on the starboard side is referred to as "starboard outboard motor 13a", and the outboard motor 13 on the port side is referred to as "port outboard motor 13b".

[0017] Figure 2 is a block diagram for schematically explaining the configuration of a marine vessel propulsion system mounted on the marine vessel 10 of Figure 1. In Figure 2, the marine vessel propulsion system 16 includes a BCU 17, an MFD (Multi Function Display) 18, a GNSS (Global Navigation Satellite System), for example, a GPS (Global Positioning System) 19, an IMU (Inertial Measurement Unit) 20, a compass 21, a remote control unit 22, a joystick 23, a steering mechanism 24, a ship operation panel 25, a remote control ECU 26, a main operation unit 27, and an SCU 28. Each component of the marine vessel propulsion system 16 is communicably connected to each other.

[0018] The GPS 19 acquires the current position of the marine vessel 10 and transmits the current position of the marine vessel 10 to the BCU 17. The IMU 20 measures the behavior of the hull 11 and transmits the measurement result to the BCU 17. The compass 21 acquires the heading direction of the bow of the marine vessel 10 (hereinafter referred to as "the azimuth of the marine vessel 10") and transmits the azimuth of the marine vessel 10 to the BCU 17.

[0019] The remote control unit 22 has levers 22a respectively corresponding to the starboard outboard motor 13a and the port outboard motor 13b. By operating each lever 22a, the operator switches the acting direction of the thrust generated by each of the starboard outboard motor 13a and the port outboard motor 13b between forward and backward, and adjusts the magnitude of the thrust generated by each of the starboard outboard motor 13a and the port outboard motor 13b to adjust the boat speed. At this time, the remote control unit 22 transmits signals for controlling the starboard outboard motor 13a and the port outboard motor 13b to the BCU 17 and the remote control ECU 26 in accordance with the operation of the lever 22a. The joystick 23 is a control stick for maneuvering the vessel 10, and transmits a signal for moving the vessel 10 in the tilting direction to the BCU 17 and the remote control ECU 26. The steering mechanism 24 is a device for the operator to set the course of the vessel 10, and the operator turns the steering wheel 24a of the steering mechanism 24 left and right to turn the vessel 10 left or right. At this time, the steering mechanism 24 transmits the steering angle corresponding to the rotational operation of the steering wheel 24a to the remote control ECU 26 and the SCU 28.

[0020] The main operation unit 27 has a main switch 27a and a shut-off switch 27b. The main switch 27a is an operator for collectively starting and collectively stopping the power sources of the starboard outboard motor 13a and the port outboard motor 13b, and the shut-off switch 27b is a switch for urgently stopping the power sources of the starboard outboard motor 13a and the port outboard motor 13b. The MFD 18 is, for example, a color LCD display, which functions as a display that displays various types of information and also functions as a touch panel that accepts input from the operator. The ship maneuvering panel 25 has switches (not shown) corresponding to various ship maneuvering modes, and the operator operates the corresponding switch to shift the vessel 10 to a desired ship maneuvering mode, for example, a fixed point holding mode or a berthing mode.

[0021] The SCU28 is provided in accordance with each starboard outboard motor 13a and port outboard motor 13b, and controls the steering mechanism (not shown) to change the direction of thrust for each starboard outboard motor 13a and port outboard motor 13b. The BCU17 grasps the status of the ship 10 based on signals transmitted from each component of the ship propulsion system 16, determines the magnitude of thrust that each starboard outboard motor 13a and port outboard motor 13b should generate and the direction of thrust, and transmits this information to each remote control ECU26.

[0022] Each of the outboard motors 13a and 13b is equipped with a remote control ECU 26, one for each starboard outboard motor 13a and port outboard motor 13b. In response to signals transmitted from the BCU 17, steering mechanism 24, remote control unit 22, joystick 23, etc., the remote control ECU 26 transmits signals to the power source ECU (not shown) and SCU 28 of the starboard outboard motor 13a and port outboard motor 13b to control the power source and steering mechanism of the starboard outboard motor 13a and port outboard motor 13b, adjusting the magnitude and direction of thrust generated by the starboard outboard motor 13a and port outboard motor 13b. The change and adjustment of the direction of each outboard motor 13a and 13b by the steering mechanism will be referred to as "steering" below. Furthermore, since the vessel 10 does not have a bow thruster, changes in course and turns of the vessel 10 are achieved solely by steering the starboard outboard motor 13a and the port outboard motor 13b. However, the vessel 10 may be equipped with a bow thruster.

[0023] The docking mode described above is a maneuvering mode for docking the vessel 10 at a pier. In docking mode, the vessel 10 is moved along the left-right direction (hereinafter referred to as "lateral direction") of the vessel 10 from the docking control start position to the target position on the pier. The fixed-point holding mode includes Stay Point (registered trademark), Drift Point (registered trademark), and Fish Point (registered trademark). At Stay Point, the magnitude and direction of thrust of each outboard motor 13 are controlled so that the vessel 10 is kept at the target position and the bearing of the vessel 10 matches the target bearing. At Drift Point, the magnitude and direction of thrust of each outboard motor 13 are controlled so that the bearing of the vessel 10 matches the target bearing, but the vessel 10 is not kept at a predetermined position and is carried away by the wind and water currents. Furthermore, at Fishpoint, the magnitude and direction of thrust of each outboard motor 13 are controlled to keep the vessel 10 in the target position, but the heading of the vessel 10 changes due to tidal currents and wind patterns.

[0024] In these docking and berthing modes, the operator does not steer the vessel 10, and the BCU 17 determines the magnitude and direction of thrust of each outboard motor 13. In other words, both the berthing mode and the berthing mode are types of automatic operation modes.

[0025] As mentioned above, in the fixed-point holding mode and docking mode, the vessel 10 moves toward a target position relatively close to it, or the vessel 10 turns so that its bearing matches the target bearing. Therefore, in the fixed-point holding mode and docking mode, the vessel 10 does not move significantly or at high speed, and slow movement and turning in the longitudinal direction (hereinafter simply referred to as "longitudinal direction") and the lateral direction of the vessel 10 take priority. At this time, the movement mode of the vessel 10 transitions to the lateral movement mode and turning mode as appropriate.

[0026] In turning mode, the direction of action of the thrust generated by each outboard motor 13 is changed in the longitudinal direction, and the presence or absence of thrust generation is controlled to generate longitudinal thrust and turning moment. However, no lateral thrust is generated in turning mode. In other words, in turning mode, longitudinal movement control toward the target position and turning control toward the target bearing are performed. In longitudinal movement control in turning mode, this corresponds to either adjusting the longitudinal distance from the target position to the vessel 10 or adjusting the longitudinal speed of the vessel 10. In addition, turning control in turning mode corresponds to either adjusting the bearing of the vessel 10 or adjusting the angular velocity of the vessel 10 when turning.

[0027] On the other hand, in lateral movement mode, not only are changes made to the longitudinal direction of the thrust generated by each outboard motor 13, and whether or not thrust is generated, but the steering angle of each outboard motor 13 is also changed. This generates thrust in the lateral direction as well as thrust and turning moment in the longitudinal direction.

[0028] Figure 3 is a diagram illustrating the turning mode as a form of movement for a ship. Figure 3 shows a simplified diagram of the ship 10 in a plan view from above.

[0029] In turning mode, the steering mechanism fixes the orientation of the starboard outboard motor 13a so that the direction of action of the thrust fr generated by the starboard outboard motor 13a is parallel to the centerline CL of the ship 10 in the longitudinal direction. Similarly, the steering mechanism fixes the orientation of the port outboard motor 13b so that the direction of action of the thrust fl generated by the port outboard motor 13b is also parallel to the centerline CL.

[0030] In the following, thrust acting in the forward direction, i.e., thrust that moves the vessel 10 forward, will be referred to as "forward thrust," and thrust acting in the rearward direction, i.e., thrust that moves the vessel 10 rearward, will be referred to as "reverse thrust." Unless otherwise specified, the magnitude of thrust fr and thrust fl are the same.

[0031] For example, as shown in Figure 3(A), when both the starboard outboard motor 13a and the port outboard motor 13b generate forward thrusts fr and fl, a forward thrust F is generated as the resultant of the forward thrusts fr and fl and acts on the vessel 10, causing the vessel 10 to move straight forward.

[0032] As shown in Figure 3(B), when both the starboard outboard motor 13a and the port outboard motor 13b generate reverse thrusts fr and fl, a reverse thrust F is generated as the resultant of the reverse thrusts fr and fl and acts on the vessel 10, causing the vessel 10 to move straight in the rearward direction.

[0033] As shown in Figure 3(C), when only the starboard outboard motor 13a generates forward thrust fr, a turning moment M is generated that causes the ship 10 to turn counterclockwise around the center of gravity G (turning counterclockwise in the figure), and forward thrust F is generated due to the forward thrust fr. Therefore, the ship 10 moves forward while turning counterclockwise.

[0034] As shown in Figure 3(D), when only the port outboard motor 13b generates the reverse thrust fl, a turning moment M is generated that causes the ship 10 to rotate counterclockwise around the center of gravity G, and a reverse thrust F is generated due to the reverse thrust fl. Therefore, the ship 10 moves backward while rotating counterclockwise.

[0035] As shown in Figure 3(E), when the port outboard motor 13b generates a backward thrust fl and the starboard outboard motor 13a generates a forward thrust fr, the resultant force in the longitudinal direction is such that the backward thrust fl cancels out the forward thrust fr. As a result, only a turning moment M is generated that causes the ship 10 to turn counterclockwise around the center of gravity G, and the ship 10 turns counterclockwise around the center of gravity G. Furthermore, the turning moment M generated in the case shown in Figure 3(E) is greater than the turning moment M generated in the cases shown in Figures 3(C) and 3(D). Therefore, in the case shown in Figure 3(E), the ship 10 turns more quickly than in the cases shown in Figures 3(C) and 3(D).

[0036] Furthermore, in the cases shown in Figures 3(C) to 3(E), a turning moment M is generated that causes the vessel 10 to turn counterclockwise. However, by reversing the direction of action of the thrusts fr and fl generated in the cases shown in Figures 3(C) to 3(E) with respect to the longitudinal direction, a turning moment M can be generated that causes the vessel 10 to turn clockwise (clockwise in the figures).

[0037] Although it was explained that in turning mode the direction of action of thrust fr and thrust fl are fixed to be parallel to the centerline CL, the actual direction of action of thrust fr and thrust fl may be slightly tilted with respect to the centerline CL, for example, by about 1°. At this time, when viewed from above, the starboard outboard motor 13a and the port outboard motor 13b are steered to form an inverted V shape.

[0038] Incidentally, when the ship 10's maneuvering mode is in stay-point mode, the ship 10 may drift due to wind or current, causing its heading to deviate from the target heading, and furthermore, its position to deviate from the target position. In this case, the BCU 17 transitions the ship 10's movement mode to turning mode and determines the magnitude and direction of thrust of each outboard motor 13 so that the ship 10's heading matches the target heading and the ship 10 returns to its target position. However, in this case, since the ship 10's position is not far from the target position, the distance the ship 10 travels is very short, and a high ship speed is not required. Therefore, the thrust required to move the vessel 10, as determined by the BCU17 (hereinafter referred to as the "required thrust"), is small. For example, it may be less than the sum of the minimum thrusts of the two outboard motors 13 (starboard outboard motor 13a and port outboard motor 13b), but greater than or equal to the minimum thrust of one outboard motor 13. For example, if the minimum thrust of an outboard motor 13 is 0.4kN, the required thrust may be 0.6kN.

[0039] In this embodiment, in the turning mode, thrust is not generated from both the starboard outboard motor 13a and the port outboard motor 13b. Instead, thrust fr (fl) is generated only from one of the outboard motors 13a and port outboard motors 13b that is capable of generating thrust F (movement force) for the ship 10 to return to (approach) the target position and turning moment M for the ship 10's bearing to match the target bearing.

[0040] Figure 4 is a diagram illustrating an example of movement control to a target line as a movement control method for a vessel according to this embodiment. In the following description, unless otherwise specified, the position of the vessel 10 refers to the position of the center of gravity G, and the required thrust is less than the sum of the minimum thrusts of the two outboard motors 13 (starboard outboard motor 13a and port outboard motor 13b), and greater than or equal to the minimum thrust of one outboard motor 13.

[0041] In the example shown in Figure 4, a linear target line is set as the target position, and the BCU 17 determines the magnitude and direction of thrust of each outboard motor 13 so that the vessel 10 reaches the target line and the bearing of the vessel 10 coincides with the target bearing. In addition, in the example shown in Figure 4, when the vessel 10 reaches the target line, it is sufficient that the position of the vessel 10 coincides with the target line in the longitudinal direction, but the position of the vessel 10 may be either on the target line in the lateral direction. Furthermore, in the example shown in Figure 4, the target bearing and the target line are orthogonal, but they do not have to be orthogonal, and the target bearing can take any angle of intersection with the target line.

[0042] Furthermore, in the examples shown in Figures 5 to 7, which will be described later, when the vessel 10 reaches the target line, the position of the vessel 10 may be either on the target line in the left-right direction, and the target bearing may take any angle of intersection with the target line.

[0043] The example in Figure 4 shows a case where the vessel 10 is positioned forward of the target line, and in a plan view, the bearing of the vessel 10 is shifted counterclockwise from the target bearing (Figure 4(A)). In this case, the BCU 17 generates a reverse thrust fr only in the starboard outboard motor 13a. At this time, the reverse thrust F acts at the center of gravity G as a component of the reverse thrust fr, and a turning moment M is generated that causes the vessel 10 to turn clockwise (clockwise in the figure) due to the reverse thrust fr. The reverse thrust F moves the vessel 10 toward the target line, and the clockwise turning moment M turns the vessel 10 so that its bearing matches the target bearing.

[0044] The starboard outboard motor 13a continues to generate reverse thrust fr until the vessel 10 reaches the target line and the vessel 10's bearing matches the target bearing. Once the vessel 10 reaches the target line and the vessel 10's bearing matches the target bearing, the BCU 17 stops generating reverse thrust fr by the starboard outboard motor 13a (Figure 4(B)).

[0045] However, the vessel 10 does not necessarily reach the target line simultaneously with the alignment of the vessel 10's bearing with the target bearing. For example, if the vessel 10's bearing aligns with the target bearing before the vessel 10 reaches the target line, the BCU 17 generates a reverse thrust fl in the port outboard motor 13b to propel the vessel 10 straight ahead in the rearward direction. Also, if the vessel 10 reaches the target line before the vessel 10's bearing aligns with the target bearing, the BCU 17 generates a forward thrust fl in the port outboard motor 13b to generate only a turning moment M, causing the vessel 10 to turn in place.

[0046] Figure 5 is a diagram illustrating an example of movement control to a target line as a ship movement control method according to this embodiment.

[0047] In the example shown in Figure 5, a linear target line is set as the target position, and the BCU 17 determines the magnitude and direction of thrust of each outboard motor 13 so that the ship 10 reaches the target line and the ship 10's bearing matches the target bearing.

[0048] The example in Figure 5 shows a case where the vessel 10 is positioned forward of the target line, and in a plan view, the bearing of the vessel 10 is shifted clockwise relative to the target bearing (Figure 5(A)). In this case, the BCU 17 generates a reverse thrust fl only in the port outboard motor 13b. At this time, the reverse thrust F acts at the center of gravity G as a component of the reverse thrust fl, and a turning moment M is generated that causes the vessel 10 to turn counterclockwise (turned counter-clockwise in the figure) due to the reverse thrust fl. The reverse thrust F moves the vessel 10 toward the target line, and the counterclockwise turning moment M turns the vessel 10 so that its bearing matches the target bearing.

[0049] Then, the port outboard motor 13b continues to generate reverse thrust fl until the vessel 10 reaches the target line and the vessel 10's bearing matches the target bearing. Once the vessel 10 reaches the target line and the vessel 10's bearing matches the target bearing, the BCU 17 stops generating reverse thrust fl by the port outboard motor 13b (Figure 5(B)).

[0050] However, as in the example in Figure 4, the vessel 10 does not necessarily reach the target line simultaneously with the alignment of the vessel 10's bearing with the target bearing. For example, if the vessel 10's bearing aligns with the target bearing before the vessel 10 reaches the target line, the BCU 17 generates a reverse thrust fr in the starboard outboard motor 13a to propel the vessel 10 straight ahead in the rearward direction. Also, if the vessel 10 reaches the target line before the vessel 10's bearing aligns with the target bearing, the BCU 17 generates a forward thrust fr in the starboard outboard motor 13a to generate only a turning moment M, causing the vessel 10 to turn in place.

[0051] Figure 6 is a diagram illustrating an example of movement control to a target line as a ship movement control method according to this embodiment.

[0052] In the example in Figure 6, a linear target line is set as the target position, and the BCU 17 determines the magnitude and direction of thrust of each outboard motor 13 so that the ship 10 reaches the target line and the bearing of the ship 10 matches the target bearing.

[0053] The example in Figure 6 shows a case where the vessel 10 is positioned aft of the target line, and in a plan view, the bearing of the vessel 10 is shifted counterclockwise from the target bearing (Figure 6(A)). In this case, the BCU 17 generates forward thrust fl only in the port outboard motor 13b. At this time, the forward thrust F acts at the center of gravity G as a component of the forward thrust fl, and a turning moment M is generated that causes the vessel 10 to turn clockwise (clockwise in the figure) due to the forward thrust fl. The forward thrust F moves the vessel 10 toward the target line, and the clockwise turning moment M turns the vessel 10 so that its bearing matches the target bearing.

[0054] The port outboard motor 13b continues to generate forward thrust fl until the vessel 10 reaches the target line and the vessel 10's bearing matches the target bearing. Once the vessel 10 reaches the target line and the vessel 10's bearing matches the target bearing, the BCU 17 stops generating forward thrust fl from the port outboard motor 13b (Figure 6(B)).

[0055] However, as in the example in Figure 4, the vessel 10 does not necessarily reach the target line simultaneously with the alignment of the vessel 10's bearing with the target bearing. For example, if the vessel 10's bearing aligns with the target bearing before the vessel 10 reaches the target line, the BCU 17 generates forward thrust fr in the starboard outboard motor 13a to propel the vessel 10 straight forward. Also, if the vessel 10 reaches the target line before the vessel 10's bearing aligns with the target bearing, the BCU 17 generates reverse thrust fr in the starboard outboard motor 13a to generate only a turning moment M, causing the vessel 10 to turn in place.

[0056] Figure 7 is a diagram illustrating an example of movement control to a target line as a ship movement control method according to this embodiment.

[0057] In the example shown in Figure 7, a linear target line is set as the target position, and the BCU 17 determines the magnitude and direction of thrust of each outboard motor 13 so that the ship 10 reaches the target line and the ship 10's bearing matches the target bearing.

[0058] The example in Figure 7 shows a case where the vessel 10 is positioned aft of the target line, and in a plan view, the bearing of the vessel 10 is shifted clockwise from the target bearing (Figure 7(A)). In this case, the BCU 17 generates forward thrust fr only in the starboard outboard motor 13a. At this time, the forward thrust F acts at the center of gravity G as a component of the forward thrust fr, and a turning moment M is generated that causes the vessel 10 to turn counterclockwise (turned counterclockwise in the figure) due to the forward thrust fr. The forward thrust F moves the vessel 10 toward the target line, and the counterclockwise turning moment M turns the vessel 10 so that its bearing matches the target bearing.

[0059] The starboard outboard motor 13a continues to generate forward thrust fr until the vessel 10 reaches the target line and the vessel 10's bearing matches the target bearing. Once the vessel 10 reaches the target line and the vessel 10's bearing matches the target bearing, the BCU 17 stops generating forward thrust fr from the starboard outboard motor 13a (Figure 6(B)).

[0060] However, as in the example in Figure 4, the vessel 10 does not necessarily reach the target line simultaneously with the alignment of the vessel 10's bearing with the target bearing. For example, if the vessel 10's bearing aligns with the target bearing before the vessel 10 reaches the target line, the BCU 17 generates forward thrust fl in the port outboard motor 13b to propel the vessel 10 straight forward. Also, if the vessel 10 reaches the target line before the vessel 10's bearing aligns with the target bearing, the BCU 17 generates reverse thrust fl in the port outboard motor 13b to create only a turning moment M, causing the vessel 10 to turn in place.

[0061] According to the target line movement control shown in Figures 4 to 7, if the required thrust is less than the sum of the minimum thrusts of the two outboard motors 13 (starboard outboard motor 13a and port outboard motor 13b) and greater than or equal to the minimum thrust of one outboard motor 13, thrust fr(fl) is generated only in one outboard motor 13. Furthermore, after thrust fr(fl) is generated, the outboard motor 13 continues to generate thrust fr(fl) until the vessel 10 reaches the target line and the bearing of the vessel 10 matches the target bearing. Therefore, the power source and propeller of each outboard motor 13 are not intermittently connected by a clutch. As a result, there is no shift noise when the power source and propeller are connected by a clutch, nor is there any shift shock associated with the connection and disconnection of the power source and propeller by a clutch, and as a result, the comfort of the vessel's crew can be improved.

[0062] Furthermore, in the movement control to the target line shown in Figures 4 to 7, as described above, the outboard motor 13 that should generate thrust and the direction of action of the generated thrust differ depending on whether the ship 10 is positioned aft or forward of the target line, and whether the bearing of the ship 10 is shifted clockwise or counterclockwise relative to the target bearing in a plan view.

[0063] Incidentally, in the movement control to the target line shown in Figures 4 to 7 above, if the heading of the ship 10 coincides with the target heading before the ship 10 reaches the target line, or if the ship 10 reaches the target line before the heading of the ship 10 coincides with the target heading, thrust is also generated in the remaining outboard motor 13. However, even in such cases, after thrust fr(fl) is generated in any of the outboard motors 13, thrust fr(fl) continues to be generated until the ship 10 reaches the target line and the heading of the ship 10 coincides with the target heading. In other words, since there is no intermittent connection between the power source and the propeller clutch in any of the outboard motors 13, the comfort of the ship's crew can be improved.

[0064] In the movement control to the target line shown in Figures 4 to 7 above, it is assumed that the required thrust remains constant until the vessel 10 reaches the target line and the bearing of the vessel 10 matches the target bearing. However, the required thrust may change in accordance with the change in the relative position between the vessel 10 and the target line. For example, the required thrust may decrease as the vessel 10 approaches the target line, or as the bearing of the vessel 10 approaches the target bearing.

[0065] In this way, when the required thrust is small, the required thrust may fall below the minimum thrust of one outboard motor 13 before the vessel 10 reaches the target line and the vessel 10's bearing matches the target bearing. In such cases, the BCU 17 shifts the shift state of all outboard motors 13 to the neutral state to stop the generation of thrust fr(fl), and allows the vessel 10 to move by inertia.

[0066] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications and changes are possible within the scope of its gist.

[0067] For example, the movement control to the target line shown in Figures 4 to 7 above assumes that the ship's maneuvering mode has shifted to the stay point mode. However, the maneuvering mode to which the movement control to the target line shown in Figures 4 to 7 can be applied is not limited to the stay point mode. For example, the movement control to the target line shown in Figures 4 to 7 may also be applied to the docking mode.

[0068] In the embodiment described above, the vessel 10 is equipped with two outboard motors 13, but the vessel 10 may be equipped with three or more outboard motors 13. In this case, the outboard motor 13 on the far left and the outboard motor 13 on the far right are used to control movement to the target line shown in Figures 4 to 7. Alternatively, the vessel 10 may be equipped with inboard and outboard motors instead of outboard motors 13. [Explanation of Symbols]

[0069] fr,fl thrust, G center of gravity, 10 vessel, 12 stern, 13a starboard outboard, 13b port outboard, 17 BCU

Claims

1. A method for controlling the movement of a ship, comprising propellers on at least the starboard and port sides of the stern, and performing forward and backward movement control toward a target position and turning control toward a target bearing, A method for controlling the movement of a ship, wherein, when the required thrust is less than the sum of the minimum thrusts of two propellers and greater than or equal to the minimum thrust of one propeller, thrust is generated only in one of the propellers on the starboard side and the port side that is capable of generating the force necessary for the ship to approach the target position and the turning moment necessary for the ship's bearing to match the target bearing.

2. The method for controlling the movement of a vessel according to claim 1, wherein the forward and backward movement control is either adjusting the distance in the forward and backward direction from the target position to the vessel, or adjusting the speed of the vessel in the forward and backward direction.

3. The method for controlling the movement of a ship according to claim 1, wherein the turning control is either adjusting the heading of the ship or adjusting the angular velocity of the ship when it turns.

4. A method for controlling the movement of a ship according to claim 1, wherein when the ship is positioned forward of the target position and the ship's bearing is shifted counterclockwise with respect to the target bearing in a plan view, thrust for rearward movement is generated only in the starboard propeller.

5. A method for controlling the movement of a ship according to claim 1, wherein when the ship is positioned forward of the target position and the ship's bearing is shifted clockwise with respect to the target bearing in a plan view, thrust for rearward movement is generated only in the port-side propeller.

6. A method for controlling the movement of a ship according to claim 1, wherein when the ship is positioned aft of the target position and the ship's bearing is shifted counterclockwise with respect to the target bearing in a plan view, thrust for forward movement is generated only in the port-side propeller.

7. The method for controlling the movement of a ship according to claim 1, wherein when the ship is located aft of the target position and the ship's bearing is shifted clockwise with respect to the target bearing in a plan view, thrust for forward movement is generated only in the starboard propeller.

8. The method for controlling the movement of a ship according to claim 1, wherein, while thrust is being generated in only one of the thrusters on the starboard side and the thrusters on the port side, the connection between the power source and the propeller of the thrust-generating thruster is not disconnected.

9. The method for controlling the movement of a ship according to claim 1, wherein the required thrust changes in accordance with a change in the relative position between the ship and the target position.

10. The method for controlling the movement of a vessel according to claim 9, wherein the required thrust decreases as the vessel approaches the target position.

11. A method for controlling the movement of a ship according to claim 10, wherein if the required thrust falls below the minimum thrust of one propeller, the generation of thrust by all propellers is stopped.

12. A vessel equipped with propellers on at least the starboard and port sides of the stern, and capable of controlling forward and backward movement toward a target position and turning toward a target bearing, A ship that, when the required thrust is less than the sum of the minimum thrusts of two propellers and greater than or equal to the minimum thrust of one propeller, generates thrust in only one of the starboard and port propellers that is capable of generating the force necessary for the ship to approach the target position and the turning moment necessary for the ship's bearing to coincide with the target bearing.

13. A method for controlling the movement of a ship, comprising propellers on at least the starboard and port sides of the stern, and performing forward and backward movement control toward a target position and turning control toward a target bearing, A method for controlling the movement of a ship, wherein, if the required thrust is less than the sum of the minimum thrusts of the two propellers, but greater than or equal to the minimum thrust of one propeller, thrust is generated in only one of the propellers, either the starboard propeller or the port propeller.

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