BOAT CONTROL SYSTEM AND BOAT

Abstract

A boat control system includes a plurality of boat propulsion devices, a controller, a manual operator, and a sensor. When the manual operator accepts an operation to request a steering mode, based on detection results of the sensor with respect to at least two of the plurality of boat propulsion devices, the controller is configured or programmed to change a steering angle of at least one of the at least two boat propulsion devices to achieve a target angle relationship such that a degree to which thrusts cancel each other out is greater than before the steering mode is requested, and when the steering angles of the at least two boat propulsion systems come to be the target angle relationship, to change the thrusts of the at least two boat propulsion devices to thrusts corresponding to the steering mode.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2024-006628 filed on Jan. 19, 2024. The entire contents of this application are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The technologies disclosed herein relate to boat control systems and boats.

2. Description of the Related Art

A system for controlling the movement of a boat is known and includes a plurality of boat propulsion devices and a controller that controls the thrust and steering angle of each of the plurality of boat propulsion devices. For example, a system has been proposed that controls the steering angle and shift state of each of two boat propulsion devices so that the steering angle and shift state correspond to the selected steering mode (see JP 2010-195388 A and JP 2018-079742 A).

The above-mentioned conventional technology is configured to change the thrust (shift state) of the boat propulsion device before the steering angles of the two boat propulsion devices come to be in an angle relationship corresponding to the selected steering mode. As a result, there is a possibility that the boat body will move or turn in an unintended direction once or temporarily immediately after the steering mode is initiated.

SUMMARY OF THE INVENTION

Example embodiments of the present invention disclose technologies that can solve one or more of the above-mentioned problems.

A boat control system according to an example embodiment of the present invention includes a plurality of boat propulsion devices able to be steered 180 degrees or more about a steering axis, a controller configured or programmed to control a thrust and a steering angle of each of the plurality of boat propulsion devices, a manual operator to accept operations, and an angle sensor to detect the steering angle of each of the plurality of boat propulsion devices. The controller is configured or programmed to, when the manual operator accepts an operation to request a steering mode, perform a steering angle change process for at least two of the plurality boat propulsion devices to, based on detection results of the angle sensor, change a steering angle of at least one of the at least two boat propulsion devices to achieve a target angle relationship such that a degree to which the thrusts cancel each other out is greater than before the steering mode is requested, and when the steering angles of the at least two boat propulsion systems come to be in the target angle relationship, perform a thrust change process to change the thrusts of the at least two boat propulsion devices to thrusts corresponding to the steering mode. The boat control system is able to reduce or prevent the boat body from moving or turning in an unintended direction immediately after the steering mode is initiated, as compared to, e.g., a configuration in which the thrusts of the boat propulsion devices are changed before the steering angles of at least two boat propulsion devices come to be in a target angle relationship.

The technologies disclosed herein can be implemented in various example embodiments, e.g., boats, control devices provided on boats, control methods for boats, computer programs for implementing functions of those devices or methods, and non-transitory recording media including the computer programs.

According to the technologies disclosed herein, it is possible to reduce or prevent the movement or turning of boat bodies in an unintended direction immediately after the steering mode is initiated.

The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically illustrating a configuration of a boat according to a first example embodiment of the present invention.

FIG. 2 is a side view schematically illustrating a configuration of a first outboard motor according to the first example embodiment of the present invention.

FIG. 3 is a front view illustrating a configuration of a joystick device according to the first example embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a boat control system according to the first example embodiment of the present invention.

FIG. 5 is a schematic view illustrating a control of the outboard motor by a joystick according to the first example embodiment of the present invention.

FIG. 6 is a flowchart illustrating a flow of an outboard motor control at a start of a joystick mode according to the first example embodiment of the present invention.

FIG. 7 is a schematic view illustrating a steering of an outboard motor by a mode transition process in a comparative example.

FIG. 8 is a schematic view illustrating a steering of the outboard motor by a mode transition process according to the first example embodiment of the present invention.

FIG. 9 is a block diagram illustrating a configuration of a boat control system according to a second example embodiment of the present invention.

FIG. 10 is a schematic view illustrating a steering of an outboard motors by a mode transition process according to the second example embodiment of the present invention.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

The first example embodiment of the present invention will be described with reference to FIGS. 1 to 8. As shown in FIGS. 1 and 4, the boat 1A includes a boat body 10, a first outboard motor 100P (a boat propulsion device, an example of a first boat propulsion device), a second outboard motor 100S (a boat propulsion device, an example of a second boat propulsion device), a steering device 200 (an example of a manual operator) that accepts operations to steer the boat 1A, a controller 300 configured or programmed to control a thrust and a steering angle of the outboard motors 100P, 100S, a position sensor 260 to detect a position of the boat body 10, and an azimuth sensor 270 to detect a turning of the boat body 10. The outboard motors 100P, 100S, the steering device 200, the controller 300, the position sensor 260, the azimuth sensor 270, and the steering angle sensor 280 are elements of the boat control system 400A.

FIG. 1 and the other figures described below show arrows representing each direction with respect to the position of the boat 1A. More specifically, each figure shows arrows representing the front direction (FRONT), rear direction (REAR), left direction (LEFT), right direction (RIGHT), upper direction (UPPER), and lower direction (LOWER), respectively, as appropriate. The front-rear direction, left-right direction, and upper-lower (vertical) direction are orthogonal to each other.

The boat body 10 of the boat 1A is for the occupants to ride. As shown in FIG. 1, the boat body 10 includes a pilot seat 12.

The outboard motors 100P, 100S are attached to the stern of the boat body 10 to generate thrusts to propel the boat body 10. As shown in FIG. 1, the first outboard motor 100P is located on the port side of the boat body 10, and the second outboard motor 100S is located on the starboard side of the boat body 10. The configuration of the first outboard motor 100P will be described in detail below. Since the second outboard motor 100S has the same structure as the first outboard motor 100P, identical parts or elements are marked with identical symbols, and descriptions thereof are omitted. When the elements provided in the first outboard motor 100P and those provided in the second outboard motor 100S are described separately, “P” is added to the end of the sign of the elements provided in the first outboard motor 100P, and “S” is added to the end of the sign of the elements provided in the second outboard motor 100S.

The first outboard motor 100P is attached to the stern of the boat body 10 via a bracket 180. The outboard motor 100P is supported by the bracket 180 in a displaceable range from a tilt-down state in which the propeller 140, which is described below, is positioned underwater to a tilt-up state in which the propeller 140 is positioned above the water surface. In the following, the outboard motor 100P in the reference attitude (attitude shown in FIG. 2) will be described unless otherwise noted. The reference attitude is one in which a rotation axis Ad of the drive shaft 124, which is described below, extends in the upper-lower direction and a rotation axis Ap of the propeller shaft 142 extends in the front-rear direction.

As shown in FIG. 2, the outboard motor 100P includes an upper unit 110 attached to the boat body 10 via the bracket 180, a lower unit 130 arranged below the upper unit 110, and a steering mechanism 160P interposed between the upper unit 110 and the lower unit 130.

The upper unit 110 includes a cowl 112, an upper case 114, an engine 120, a drive shaft 124, and an electronic control unit (ECU) 190P, as shown in FIG. 2.

The cowl 112 is a housing located on top of the outboard motor 100P. The upper case 114 is a housing arranged below the cowl 112 and is attached to the boat body 10 via the bracket 180.

The engine 120 is a prime mover to generate power to drive the outboard motor 100P and is located inside the cowl 112. The engine 120 includes an engine body 121 and an intake device 125. The engine body 121 has a known configuration including a cylinder block (not shown) provided with a plurality of cylinders (not shown), a piston (not shown) disposed inside each cylinder and reciprocating as a mixture of fuel and air is burned, and a crankshaft 122 rotating as the piston reciprocates. The crankshaft 122 is arranged in an attitude extending in the upper-lower direction as shown in FIG. 2. The intake device 125 has a known configuration including an intake channel 126 that supplies air to the inside of the cylinder block, a throttle valve 127P provided in the intake channel 126, and a throttle actuator 128P that controls the opening (throttle opening) of the throttle valve 127P. The throttle actuator 128P includes, e.g., an electric motor. The throttle actuator 128P operates the throttle valve 127P to change the throttle opening. The change in the throttle opening changes the flow rate of air supplied to the inside of the cylinder block, thus changing the output of the engine 120 (rotation speed of the crankshaft 122). The throttle actuator 128P is communicatively connected to the ECU 190P.

The drive shaft 124 is a rod-shaped member, connected to the lower end of the crankshaft 122, and positioned in an attitude in which its rotation axis Ad extends in the upper-lower direction. The drive shaft 124 rotates along with the rotation of the crankshaft 122. Most of the drive shaft 124 is located inside the cowl 112 and the upper case 114. The lower end of the drive shaft 124 protrudes downward from the upper case 114 and extends into the inside of the lower unit 130.

The ECU 190P is located inside the cowl 112. The ECU 190P includes a processor such as a central processing unit (CPU) and a storage device such as read only memory (ROM) and random access memory (RAM). The storage device stores various programs and data to control the outboard motor 100P.

The lower unit 130 includes a lower case 132, a propeller 140, a propeller shaft 142, and a shift mechanism 150P, as shown in FIG. 2.

The lower case 132 is a housing arranged below the upper case 114.

The propeller 140 is a rotating member including a plurality of blades and generates a thrust by rotating. The propeller shaft 142 is a rod-shaped member and is arranged in a position extending in a front-rear direction. The rear end of the propeller shaft 142 protrudes outside the lower case 132, and the remaining portion is housed within the lower case 132. The propeller 140 is attached to the rear end of the propeller shaft 142. As the propeller shaft 142 rotates about the rotation axis Ap, the propeller 140 also rotates.

The shift mechanism 150P is connected to the lower end of the drive shaft 124 and to the front end of the propeller shaft 142. The shift mechanism 150P has a known configuration including, e.g., a forward gear, a backward gear, and a clutch. By switching the engagement of the clutch with the two gears, the direction of rotation transmitted from the drive shaft 124 to the propeller shaft 142 is switched.

The lower unit 130 further includes a shift actuator 152P that switches the shift state of the outboard motor 100P. The shift actuator 152P includes, e.g., an electric motor. The shift actuator 152P is connected to a clutch provided in the shift mechanism 150P and is configured to actuate the clutch to switch the shift state of the outboard motor 100P among the forward movement, backward movement, and neutral states by switching engagement with the forward and the backward gear. The forward movement state is a state in which the clutch engages the forward gear, the rotation of the drive shaft 124 is transmitted to the propeller shaft 142 as forward rotation, and the propeller 140, which rotates in the forward direction with the propeller shaft 142, generates thrust in the forward direction. The backward movement state is a state in which the clutch engages the backward gear, the rotation of the drive shaft 124 is transmitted to the propeller shaft 142 as reverse rotation, and the propeller 140, which rotates in the reverse direction with the propeller shaft 142, generates thrust in the backward direction. The neutral state is a state in which the clutch is not engaged with either the forward gear or the backward gear so that the rotation of the drive shaft 124 is not transmitted to the propeller shaft 142 and the propeller 140 does not generate thrust. The shift actuator 152P is communicatively connected to the ECU 190P.

The steering mechanism 160P changes the direction of the thrust generated by the outboard motor 100P and is configured to rotate the lower unit 130 relative to the upper unit 110. As shown in FIG. 2, for example, the steering mechanism 160P has a known configuration including a pinion 161 that rotates along with the lower unit 130, a steering shaft 162 that is attached to the pinion 161 and through which the drive shaft 124 can be inserted, and a rack 163 that engages the pinion 161 and moves linearly. The steering mechanism 160P is driven by a steering actuator 164P (see also FIG. 4). The steering actuator 164P is a drive device to linearly move the rack 163 and includes, e.g., an electric motor. When the rack 163 is moved linearly by the driving force of the steering actuator 164P, the pinion 161 rotates. This rotation causes the lower unit 130 to rotate around the rotation axis Ad of the drive shaft 124 as the steering shaft. In conjunction with this rotation, the propeller shaft 142 rotates about the rotation axis Ad. The steering actuator 164P is communicatively connected to the ECU 190P.

In this specification, the steering angle is defined as follows. As shown in FIG. 5, the steering angle is 0° when the orientation of the lower unit 130 is such that the rotation axis Ap of the propeller shaft 142 is parallel to the centerline C of the boat body 10 and the propeller 140 is directed rearward. Then, the clockwise rotation of the lower unit 130, viewed from above, is referred to as the turning in the positive direction, and the counterclockwise rotation is referred to as the turning in the negative direction. The rotation angle of the propeller shaft 142 from the 0° steering angle position is referred to as the turning angle. The lower unit 130 can be turned ±180° from the 0° steering angle position, or 180° clockwise and counterclockwise, respectively. In other words, the lower unit 130 can be turned from a steering angle of +180°, back to a steering angle of +0°, and then to a steering angle of −180°, and from a steering angle of −180°, back to a steering angle of +0°, and then to a steering angle of +180°. That is, the maximum range (total steering angle) over which the lower unit 130 can be turned is 360°.

The steering device 200 is located near the pilot seat 12 and accepts operations by the steering person to control the movement of the boat body 10. The steering device 200 includes a steering wheel 210, shift/throttle levers 220P, 220S, and a joystick device 230, as shown in FIGS. 1 and 4.

The steering wheel 210 accepts operations by the steering person to request a turning direction of the boat body 10 and is configured to be rotatable. As shown in FIG. 4, a steering sensor 212 is connected to the steering wheel 210. The steering sensor 212 outputs a steering signal indicating the direction and angle of rotation of the steering wheel 210.

The shift/throttle levers 220P, 220S accept operations by the steering person to request a magnitude of thrust and the shift state of the two outboard motors 100P, 100S, respectively. The shift/throttle levers 220P, 220S can be moved forward and backward from the neutral position. As shown in FIG. 4, throttle sensors 222P, 222S are connected to the shift/throttle levers 220P, 220S, respectively. The throttle sensors 222P, 222S output throttle signals indicating the operation direction and operation amount of the shift/throttle levers 220P, 220S, respectively.

The joystick device 230 includes a rod-shaped joystick 232 that accepts operations by the steering person to control the movement of the boat body 10 and a joystick base 234 that supports the joystick 232 in a tiltable and twistable manner, as shown in FIG. 3 (an example of a mode switch). The joystick 232 is urged by a spring or other force source to automatically return to the default position (where the joystick 232 is upright) when no operating force is applied. The joystick 232 can be tilted forward, backward, leftward, rightward, and diagonally from the default position, and can be operated by twisting clockwise and counterclockwise, and can be tilted while twisting.

The joystick base 234 includes a joystick button 240, a stay point button 241, a drift point button 242, and a fish point button 243. The joystick button 240 is used to switch the steering mode between the normal steering mode, in which the steering wheel 210 and the shift/throttle levers 220P, 220S are used to control the boat, and the joystick mode, in which the joystick device 230 is used to control the boat. The stay point button 241, the drift point button 242, and the fish point button 243 are buttons to operate the transition to the set point mode described below.

The joystick base 234 is further provided with a joystick sensor 250 connected to the joystick 232 (see FIG. 4). The joystick sensor 250 outputs joystick signals indicating the tilt direction and tilt amount (e.g., tilt angle) and the twist direction and twist amount (e.g., twist angle) of the joystick 232. The joystick sensor 250 further outputs an operation signal indicating that any of the buttons 240, 241, 242, 243 was pushed.

The position sensor 260 detects the position of the boat body 10. The position sensor 260 may be a Global Navigation Satellite System (GNSS) receiver, such as the Global Positioning System (GPS). The position sensor 260 detects the position of the boat body 10 and outputs a position signal indicating the position of the boat body 10.

The azimuth sensor 270 detects the azimuth of the boat body 10. The azimuth sensor 270 may be, e.g., an inertial measurement unit (IMU). The azimuth sensor 270 detects the azimuth of the boat body 10 and outputs the azimuth signal indicating the azimuth of the boat body 10.

The steering angle sensor 280 (an example of an angle sensor) individually detects the steering angle of the first outboard motor 100P and the steering angle of the second outboard motor 100S. The steering angle sensor 280 detects the steering angle of each outboard motor 100P, 100S and outputs a steering angle signal indicating the steering angle of each outboard motor 100P, 100S.

The controller 300 includes, e.g., a CPU, a multi-core CPU, and a programmable device (e.g., field programmable gate array (FPGA), programmable logic device (PLD)). The controller 300 controls the operation of the boat body 10. In other words, the controller 300 controls the magnitude and direction of the thrust of the outboard motors 100P, 100S, respectively, according to the operations accepted by the steering device 200.

The controller 300 includes a storage device. The storage device includes, e.g., ROM, RAM, hard disk drive (HDD), and solid-state drive (SDD). The storage device stores various programs and data and is used as a work area or data storage area when executing various processes. For example, a computer program to execute the mode transition process described below is stored in the storage device. This computer program is provided, e.g., in a computer-readable recording medium such as a CD-ROM, DVD-ROM, or USB memory (not shown), or it can be obtained from an external device (e.g., a server in the cloud) via a communication interface (not shown) and stored in a storage device in a manner that can be executed on the boat control system 400A.

The controller 300 is communicatively connected to the ECUs 190P, 190S, the position sensor 260, the azimuth sensor 270, the steering sensor 212, the throttle sensors 222P, 222S, and the joystick sensor 250.

The controller 300 obtains the position and speed of the boat body 10 by receiving position signals from the position sensor 260. The controller 300 obtains the azimuth of the boat body 10 by receiving azimuth signals from the azimuth sensor 270.

The controller 300 receives steering signals from the steering sensor 212, throttle signals from the throttle sensors 222P, 222S, and joystick signals and operation signals from the joystick sensor 250. The controller 300 outputs command signals to the ECUs 190P, 190S based on these signals. The ECU 190P outputs command signals to the throttle actuator 128P, the shift actuator 152P, and the steering actuator 164P according to the command signals from the controller 300. The ECU 190S outputs command signals to the throttle actuator 128S, the shift actuator 152S, and the steering actuator 164S according to the command signal from the controller 300.

In the present example embodiment, the controller 300 sets the steering mode to the normal steering mode by default. The normal steering mode is a mode in which the boat is primarily operated using the steering wheel 210 and the shift/throttle levers 220P, 220S.

In the normal steering mode, the controller 300 receives steering signals from the steering sensor 212 and throttle signals from the throttle sensors 222P, 222S. The controller 300 outputs command signals to the throttle actuators 128P, 128S, the shift actuators 152P, 152S, and the steering actuators 164P, 164S via the ECUs 190P, 190S based on these signals.

For example, the controller 300 outputs a command signal corresponding to the operating direction of the shift/throttle lever 220P to the shift actuator 152P. The shift actuator 152P activates the clutch of the shift mechanism 150P to switch the engagement of the clutch with respect to the forward gear and the backward gear based on the received command signal. As a result, the shift state of the first outboard motor 100P is switched among the forward movement state, the backward movement state, and the neutral state. Similarly, the controller 300 outputs a command signal corresponding to the operating direction of the shift/throttle lever 220S to the shift actuator 152S. The shift actuator 152S activates the clutch of the shift mechanism 150S to switch the engagement of the clutch with respect to the forward gear and the backward gear based on the received command signal. As a result, the shift state of the second outboard motor 100S is switched among the forward movement state, the backward movement state, and the neutral state.

The controller 300 also outputs a command signal corresponding to the operating amount of the shift/throttle lever 220P to the throttle actuator 128P. The throttle actuator 128P changes the opening of the throttle valve 127P based on the received command signal. This changes the rotation speed of the crankshaft 122, which in turn changes the rotation speed of the propeller shaft 142 and the propeller 140, thus changing the magnitude of the thrust generated by the first outboard motor 100P. Similarly, the controller 300 outputs a command signal corresponding to the operating amount of the shift/throttle lever 220S to the throttle actuator 128S. The throttle actuator 128S changes the opening of the throttle valve 127S based on the received command signal. This changes the magnitude of the thrust generated by the second outboard motor 100S.

The controller 300 outputs command signals corresponding to the direction and amount of rotation of the steering wheel 210 to the steering actuators 164P, 164S via the ECUs 190P, 190S. The steering actuator 164P controls the steering mechanism 160P based on the received command signals to change the direction of the lower unit 130, i.e., the steering angle of the first outboard motor 100P. This changes the direction of the thrust of the first outboard motor 100P. Similarly, the steering actuator 164S controls the steering mechanism 160S based on the received command signal to change the direction of the lower unit 130, i.e., the steering angle of the second outboard motor 100S. This changes the direction of the thrust of the second outboard motor 100S. In this way, the azimuth of the boat body 10 is controlled.

For example, when the steering wheel 210 is turned to the left from the neutral position, the controller 300 outputs a command signal to the steering actuators 164P, 164S to steer the lower units 130 of the two outboard motors 100P, 100S clockwise from the 0° turning angle position. This causes the boat body 10 to turn to the left. When the steering wheel 210 is turned to the right from the neutral position, the controller 300 outputs a command signal to the steering actuators 164P, 164S to steer the lower units 130 of the two outboard motors 100P, 100S counterclockwise from the 0° turning angle position. This causes the boat body 10 to turn to the right.

When the joystick device 230 receives an operation to switch the joystick mode from off to on (joystick mode start operation), the controller 300 receives the operation signal from the joystick sensor 250 and switches the steering mode from the normal steering mode to the joystick mode. The joystick mode start operation is, e.g., a short press of the joystick button 240 by the steering person. When the joystick device 230 receives an operation to switch the joystick mode from on to off (joystick mode deactivation operation), the controller 300 receives the operation signal from the joystick sensor 250 and switches the steering mode from the joystick mode to the normal steering mode. The joystick mode deactivation operation is, e.g., a long press of the joystick button 240 by the steering person.

When the boat 1A is controlled in the joystick mode, the controller 300 receives joystick signals from the joystick sensor 250. The controller 300 outputs command signals to the throttle actuators 128P, 128S, the shift actuators 152P, 152S and the steering actuators 164P, 164S via the ECUs 190P, 190S based on these signals.

For example, when the joystick 232 is tilted, the controller 300 outputs command signals to the throttle actuators 128P, 128S, the shift actuators 152P, 152S, and the steering actuators 164P, 164S to move the boat body 10 in the direction in which the joystick 232 is tilted at a speed corresponding to the amount by which the joystick 232 is tilted. When the joystick 232 is twisted (rotated), the controller 300 outputs command signals to the throttle actuators 128P, 128S, the shift actuators 152P, 152S, and the steering actuators 164P, 164S to turn the boat body 10 in the direction in which the joystick 232 is twisted at an angular speed corresponding to the amount by which the joystick 232 is twisted. The magnitude of thrust, the shift state, and the steering angle of the outboard motors 100P, 100S are controlled based on the output command signals.

In this example embodiment, the set point mode is selected as the steering mode. The set point mode includes stay point mode, drift point mode, and fish point mode. The stay point mode holds the position and azimuth of the boat body 10, the fish point mode holds the position of the boat body 10, and the drift point mode holds the azimuth of the boat body 10.

When the boat 1A is controlled in the joystick mode, if the joystick device 230 accepts a press of the stay point button 241 by the steering person, the controller 300 receives the operation signal from the joystick sensor 250 and switches the steering mode to the stay point mode. When the boat 1A is controlled in the stay point mode, if the joystick device 230 accepts a press of the stay point button 241 by the steering person, the controller 300 receives the operation signal from the joystick sensor 250 and deactivates the stay point mode. The same applies to the fish point mode and the drift point mode.

For example, when the boat 1A is controlled in the stay point mode, the controller 300 receives signals from the azimuth sensor 270 and the position sensor 260 to obtain the current position and azimuth of the boat body 10, and outputs command signals to the throttle actuators 128P, 128S, the shift actuators 152P, 152S, and the steering actuators 164P, 164S to hold the boat body 10 in that position and azimuth. When the boat 1A is controlled in the fish point mode, the controller 300 receives signals from the position sensor 260 to obtain the current position of the boat body 10 and outputs command signals to the throttle actuators 128P, 128S, the shift actuators 152P, 152S, and the steering actuators 164P, 164S to hold the boat body 10 in that position. When boat 1A is controlled in the drift point mode, the controller 300 receives signals from the azimuth sensor 270 to obtain the current azimuth of the boat body 10 and outputs command signals to the throttle actuators 128P, 128S, the shift actuators 152P, 152S, and the steering actuators 164P, 164S to hold the boat body 10 in that azimuth. The magnitude of thrust, the shift state, and the steering angle of the outboard motors 100P, 100S are controlled based on the output command signals.

The procedure of controlling the outboard motors 100P, 100S by the boat control system 400A when the joystick mode start operation is executed while the boat 1A is travelling will be described with reference to FIGS. 6 to 8.

As shown in FIG. 6, the controller 300 determines whether there is a joystick mode start operation (S110). As described above, the determination in step S110 is made based on whether there is an operation signal from the joystick sensor 250. If the controller 300 determines that there is no joystick mode start operation (S110: N), it waits as is and, for example, continues the currently executing mode. If the controller 300 determines that there is a joystick mode start operation (S110: Y), it determines whether the shift state of the outboard motor 100P is in the neutral state (shift-out state) (S120). The determination in step S120 is made based on the shift position of the shift/throttle lever 220P, for example.

If the controller 300 determines that the shift state of the outboard motor 100P is not in the neutral state (S120: N), it returns to step S110 without shifting to the joystick mode. If the controller 300 determines that the shift state of the outboard motor 100P is in the neutral state (S120: Y), it allows the transition to the joystick mode (S130).

The controller 300 begins to change the steering angle of the first outboard motor 100P and the steering angle of the second outboard motor 100S based on the steering angle signal from the steering angle sensor 280 so that the steering angle of the first outboard motor 100P and the steering angle of the second outboard motor 100S come to be in a target angle relationship (S140: example of the steering angle change process). The target angle relationship is an angle relationship in which, with respect to the first outboard motor 100P and the second outboard motor 100S, the degree to which the thrusts cancel each other out is greater than before the joystick mode is requested. In the present example embodiment, the target angle relationship is the default angle. The default steering angle is the steering angle at which the lower units 130 of the outboard motors 100P, 100S face each other. In other words, the steering angle of the first outboard motor 100P is +90°, and the steering angle of the second outboard motor 100S is −90° (see the right figure in FIG. 7). As described above, at the default steering angle, the thrusts generated by the two outboard motors 100P, 100S cancel each other out so that the boat body 10 remains in place.

If the controller 300 determines that, after starting the steering angle change process of step S140, the steering angles of the outboard motors 100P, 100S are not in the target angle relationship (S150: N), it continues to change the steering angles of the outboard motors 100P, 100S (S140). If the controller 300 determines that the steering angles of the outboard motors 100P, 100S have become a target angle relationship (S150: Y), it stops changing the steering angles (S160) and switches the outboard motors 100P, 100S from the shift-out state to the shift-in state (S170: an example of the thrust change process). In other words, in the present example embodiment, the outboard motors 100P, 100S are switched from the shift-out state to the shift-in state when the steering angles of the first outboard motor 100P and the second outboard motor 100S come to be the default steering angles.

Next, the controller 300 controls the magnitude of thrust, the shift state, and the steering angle of the outboard motors 100P, 100S according to the position of the joystick 232 (S180). For example, the controller 300 outputs command signals to the throttle actuators 128P, 128S, the shift actuators 152P, 152S, and the steering actuators 164P, 164S so that the boat body 10 advances at a speed corresponding to the tilt amount or twist amount in the direction in which the joystick 232 is tilted or twisted. The magnitude of thrust, the shift state, and the steering angle of the outboard motors 100P, 100S are controlled based on the output command signals.

In step S190, the controller 300 determines whether the joystick mode has been deactivated. If the controller 300 receives an operation signal from the joystick sensor 250 associated with the joystick mode deactivation operation conducted by the steering person, the controller 300 determines that the joystick mode has been deactivated and switches the steering mode to the normal steering mode. If no operation signal associated with the joystick mode deactivation operation is received, the controller 300 determines that the joystick mode has not been deactivated and returns to step S180 to repeat the process.

As described above, the boat 1A in the present example embodiment includes the boat body 10 and the boat control system 400A. The boat control system 400A includes the first outboard motor 100P and the second outboard motor 100S able to be steered 180 degrees or more about a steering axis, the controller 300 that controls the thrust and steering angle of the first outboard motor 100P and the second outboard motor 100S, the steering device 200 that accepts the operation to move the boat body 10 and outputs the operation signal to the controller 300, and the steering angle sensor 280 that detects the steering angle of each outboard motor 100P, 100S and outputs a steering angle signal indicating the steering angle of each outboard motor 100P, 100S.

When the steering device 200 accepts a joystick mode start operation, the controller 300 starts changing the steering angles of the first outboard motor 100P and the second outboard motor 100S so that the steering angle of the first outboard motor 100P and the steering angle of the second outboard motor 100S come to be in the target angle relationship. At this time, both outboard motors 100P, 100S are in the shift-out state, and the outboard motors 100P, 100S are switched from the shift-out state to the shift-in state when the steering angle of the first outboard motor 100P and the steering angle of the second outboard motor 100S come to be in the target angle relationship.

Here, FIG. 7 is a schematic view illustrating the steering of the outboard motor by the mode transition process in a comparative example, and FIG. 8 is a schematic view illustrating the steering of the outboard motor by the mode transition process according to the first example embodiment. The left side of FIGS. 7 and 8 shows the status where the steering angles of the first outboard motor 100P and the second outboard motor 100S are both at the start position (see left figure) of 0° when the steering device 200 accepts the joystick mode start operation, the right side of FIGS. 7 and 8 shows the status where the steering angles of the first outboard motor 100P and the second outboard motor 100S are in the default position, and the center of FIGS. 7 and 8 shows the status in the middle of steering from the starting position to the default position.

In the comparative example, the outboard motors 100P, 100S are switched from the shift-out state to the shift-in state before the steering angles of the first outboard motor 100P and the second outboard motor 100S come to be in the default positions. Therefore, thrust is generated from each of the outboard motors 100P, 100S (see the center figure in FIG. 7), and when the steering angles of the first outboard motor 100P and the second outboard motor 100S come to be in the default positions, the boat body 10 has moved forward unintentionally (see the right figure in FIG. 7). In contrast, in the example embodiments described above, the shift-out state of the outboard motors 100P, 100S is maintained until the steering angles of the first outboard motor 100P and the second outboard motor 100S come to be in the default positions (see the center figure in FIG. 8). Therefore, when the steering angles of the first outboard motor 100P and the second outboard motor 100S come to be the default positions, the boat body 10 maintains the position it was in when the steering device 200 accepted the joystick mode start operation without moving forward or turning.

The second example embodiment will now be described with reference to FIGS. 9 and 10. The boat 1B of the second example embodiment is further provided with a third outboard motor 100C (an example of a boat propulsion device, a third boat propulsion device). The third outboard motor 100C is disposed between the first outboard motor 100P and the second outboard motor 100S at the stern of the boat body 10 (see FIG. 10). More specifically, the third outboard motor 100C is located on the centerline C of the boat body 10. The third outboard motor 100C includes a steering mechanism 160C, a steering actuator 164C, an ECU 190C, as shown in FIG. 9. The configuration of the third outboard motor 100C is similar to that of the first outboard motor 100P, so the same elements are marked with the same symbols and detailed descriptions are omitted. When the elements provided in the third outboard motor 100C are described separately from those provided in the first outboard motor 100P, a “C” is added to the end of the sign of the elements provided in the third outboard motor 100C.

As with the first outboard motor 100P, the third outboard motor 100C is configured to change the steering angle by rotating the lower unit 130 with respect to the upper unit 110. The controller 300 outputs command signals to the steering actuator 164C via the ECU 190C. The steering actuator 164C controls the steering mechanism 160C based on the received command signal to change the orientation of the lower unit 130, i.e., the steering angle of the outboard motor 100C. The outboard motors 100P, 100S, 100C, the steering device 200, the controller 300, the position sensor 260, and the azimuth sensor 270 are elements of the boat control system 400B.

The procedure of controlling the outboard motors 100P, 100S, 100C by the boat control system 400B when the joystick mode start operation is executed while the boat 1B is travelling will be described. In the following description, only the procedures that differ from those of the first example embodiment will be described, and descriptions of identical procedures will be omitted.

Here, FIG. 10 is a schematic view illustrating the steering of the outboard motors by a mode transition process according to the second example embodiment. The left side of FIG. 10 shows the status where the steering angles of the first outboard motor 100P and the second outboard motor 100S are both at the start position of 0° when the steering device 200 accepts the joystick mode start operation, the right side of FIG. 10 shows the status where the steering angles of the first outboard motor 100P and the second outboard motor 100S are in the default position, and the center of FIG. 10, the status in the middle of steering from the starting position to the default position.

As in the first example embodiment, when the steering device 200 accepts the joystick mode start operation (see the left diagram in FIG. 10), the controller 300 changes the steering angle of the first outboard motor 100P and the steering angle of the second outboard motor 100S so that the steering angles of the first outboard motor 100P and the second outboard motor 100S come to be in the target angle relationship (see the center figure in FIG. 10). At this time, both outboard motors 100P, 100S are in the shift-out state, and the outboard motors 100P, 100S are switched from the shift-out state to the shift-in state in the condition in which the steering angle of the first outboard motor 100P and the steering angle of the second outboard motor 100S come to be in the target angle relationship (see the right figure of FIG. 10).

If the controller 300 determines that the boat body 10 is turning in the positive (clockwise) direction, it steers the third outboard motor 100C in the direction in which the boat body 10 is turning, that is, in the positive (clockwise) direction (see FIG. 10). When the boat body 10 is turning in the positive (clockwise) direction, a counterclockwise water flow is generated relative to the boat body 10. The third outboard motor 100C, which is steered in the positive (clockwise) direction, acts as resistance to this water flow, thus quickly stopping the turning. In addition, if the controller 300 determines that the boat body 10 is turning in the negative (counterclockwise) direction, it steers the third outboard motor 100C in the direction in which the boat body 10 is turning, that is, in the negative (counterclockwise) direction. When the boat body 10 is turning in the negative (counterclockwise) direction, a clockwise water flow is generated relative to the boat body 10. The third outboard motor 100C, which is steered in the negative (counterclockwise) direction, acts as resistance to this water flow, thus quickly stopping the turning.

During the steering angle change process, the shift state of the third outboard motor 100C should be set to neutral with no thrust being generated. This can reduce or prevent the unintended movement of the boat body 10.

The technologies disclosed herein are not limited to the above-described example embodiments and may be modified in various ways without departing from the gist of the present invention, including the following modifications.

In the above example embodiments, the outboard motors 100P, 100S, 100C are outboard motors driven by an engine, but the outboard motors can also be electric outboard motors driven by a motor.

In the above example embodiments, both the first outboard motor 100P and the second outboard motor 100S are turned in the steering angle change process, but only one of the first and second outboard motors may be used in the steering angle change process.

In the first example embodiment, an example is shown in which the controller 300 executes the steering angle change process and the thrust change process when the joystick mode start operation is performed (see FIG. 6), but the process is not limited to this. For example, the controller 300 may execute the steering angle change process and the thrust change process when the stay point mode start operation is performed. For example, when the stay point mode start operation is performed while the controller 300 is controlling the outboard motors 100P, 100S according to the position of the joystick 232 at step S180 in FIG. 6, the processes from step S120 to step S170 in FIG. 6 may be executed.

In each of the example embodiments, the target angle relationship is not limited to the default angle, and may be an angle relationship that cancels each other out by taking into account the effects of factors such as the installation position of the outboard motors 100P, 100S, the shape of the boat body 10, and external disturbances such as wind and tide. In addition, the target angle relationship does not have to be a position relationship that completely cancels out the thrust, but can be a position relationship where the degree to which the thrusts cancel each other out is greater than before the joystick mode shift request. In addition, the operation accepted by the manual operator to request the steering mode does not have to be a joystick mode that switches from shift-out state to shift-in state, but can be an operation to request a different steering mode with different thrusts.

In the second example embodiment, the boat 1B is provided with three outboard motors 100P, 100S, 100C, but the boat may be provided with four or more outboard motors. In that case, any of the outboard motors may be used in the steering angle change process, but it is preferable to use the two outboard motors at the ends as the first and second outboard motors used in the steering angle change process. In the second example embodiment, the third outboard motor 100C is steered in addition to the first outboard motor 100P and the second outboard motor 100S, but the third outboard motor does not have to be steered in the steering angle change process for a boat including three or more outboard motors.

In the above example embodiments, the boat propulsion devices are outboard motors 100P, 100S, 100C, but the boat propulsion devices can be inboard motors, inboard/outboard motors, or jet propellers.

While example embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

Claims

1. A boat control system for controlling a boat including a boat body, the boat control system comprising: a plurality of boat propulsion devices able to be steered 180 degrees or more about a steering axis;a controller configured or programmed to control a thrust and a steering angle of each of the plurality of boat propulsion devices;a manual operator to accept operations; andan angle sensor to detect the steering angle of each of the plurality of boat propulsion devices; whereinthe controller is configured or programmed to: when the manual operator accepts an operation to request a steering mode, perform a steering angle change process for at least two of the plurality of boat propulsion devices to, based on detection results of the angle sensor, change a steering angle of at least one of the at least two boat propulsion devices to achieve a target angle relationship such that a degree to which thrusts of the plurality of boat propulsion devices cancel each other out is greater than before the steering mode is requested; andwhen the at least two boat propulsion systems come to be in the target angle relationship, perform a thrust change process to change the thrusts of the at least two boat propulsion devices to thrusts corresponding to the steering mode.

2. The boat control system according to claim 1, wherein in the thrust change process, the controller is configured or programmed to change the at least two boat propulsion devices from a shift-out state to a shift-in state.

3. The boat control system according to claim 1, wherein the manual operator includes a joystick; andthe steering mode is a joystick mode to control the boat based on the operation of the joystick.

4. The boat control system according to claim 2, wherein the manual operator includes a joystick; andthe steering mode is a joystick mode to control the boat based on the operation of the joystick.

5. The boat control system according to claim 1, wherein the target angle relationship is a relationship of steering angles in which the thrusts of the at least two boat propulsion devices cancel each other out.

6. The boat control system according to claim 2, wherein the target angle relationship is a relationship of steering angles in which the thrusts of the at least two boat propulsion devices cancel each other out.

7. The boat control system according to claim 1, wherein the plurality of boat propulsion devices include: a first boat propulsion device;a second boat propulsion device; anda third boat propulsion device between the first boat propulsion device and the second boat propulsion device; andthe controller is configured or programmed to change the steering angle of at least one of the first boat propulsion device or the second boat propulsion device in the steering angle change process.

8. The boat control system according to claim 2, wherein the plurality of boat propulsion devices include:a first boat propulsion device;a second boat propulsion device; anda third boat propulsion device disposed between the first boat propulsion device and the second boat propulsion device, whereinthe controller is configured or programmed to change the steering angle of at least one of the first boat propulsion device and the second boat propulsion device in the steering angle change process.

9. The boat control system according to claim 7, wherein in the steering angle change process, the controller is configured or programmed to steer the third boat propulsion device in a direction in which the boat body is turning.

10. The boat control system according to claim 8, wherein in the steering angle change process, the controller is configured or programmed to steer the third boat propulsion device in a direction in which the boat body is turning.

11. A boat control system for controlling a boat including with a boat body, the boat control system comprising: a plurality of boat propulsion devices able to be steered about a steering axis;a controller configured or programmed to control a thrust and a steering angle of each of the plurality of boat propulsion devices;a manual operator to accept operations; andan angle sensor to detect the steering angle of each of the plurality of boat propulsion device; whereinthe controller is configured or programmed to: when the manual operator accepts an operation to request a steering mode, perform a steering angle change process for at least two of the plurality of boat propulsion devices to, based on detection results of the angle sensor, change the steering angle of at least one of the at least two boat propulsion devices to achieve a target angle relationship corresponding to the steering mode; andwhen the steering angles of the at least two boat propulsion systems come to be in the target angle relationship, perform a thrust change process to change the thrusts of the at least two boat propulsion devices to thrusts corresponding to the steering mode.

12. The boat control system according to claim 1, wherein each of the at least two boat propulsion devices include: an upper unit fixed to the boat body; anda lower unit, including a propeller, below the upper unit and pivotable around the steering axis relative to the upper unit.

13. The boat control system according to claim 2, wherein each of the at least two boat propulsion devices include: an upper unit fixed to the boat body; anda lower unit, including a propeller, below the upper unit and pivotable around the steering axis relative to the upper unit.

14. The boat control system according to claim 11, wherein each of the at least two boat propulsion devices include: an upper unit fixed to the boat body; anda lower unit, including a propeller, below the upper unit and pivotable around the steering axis relative to the upper unit.

15. A boat comprising: a boat body; andthe boat control system according to claim 1.

16. A boat comprising: a boat body; andthe boat control system according to claim 2.

17. A boat comprising: a boat body; andthe boat control system according to claim 11.