BOAT CONTROL SYSTEM AND BOAT

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2024-006626 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 sets the steering angle to a predetermined default angle, starts the boat movement, detects an error between the desired movement and the actual movement of the boat, and corrects the steering angle by determining a correction angle to reduce the error (see JP 2022-091207 A).

SUMMARY OF THE INVENTION

In the conventional technology described above, the control system tends to be complex, and there is room for improvement in terms of simplification.

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

The technologies disclosed herein can be implemented, e.g., in the following example embodiments.

A boat control system for controlling a boat including a boat body includes a plurality of boat propulsion devices each being steerable by 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, an operator to accept an operation request to move the boat body and output an operation signal to the controller, and a sensor to detect a turning of the boat body and output a detection signal to the controller, wherein the controller is configured or programmed to perform, when the sensor detects a turning of the boat body in a status where the operator is not accepting an operation request to turn the boat body, a steering angle change process to change the steering angle of at least one of the plurality of boat propulsion devices to cancel the turning of the boat body.

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.

The technologies disclosed herein facilitate the steering of boats as intended by the steering person with a simple configuration.

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 of the first example embodiment of the present invention.

FIG. 5 is a schematic view illustrating a control of outboard motors 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 steering of the outboard motors by a steering angle adjustment process at the start of the joystick mode according to the first example embodiment of the present invention.

FIG. 8 is a schematic view of steering of the outboard motors by the steering angle adjustment process at the start of the joystick mode according to the first example embodiment of the present invention.

FIG. 9 is a flowchart illustrating the flow of the outboard motor control when the boat is controlled in a stay point mode according to the first example embodiment of the present invention.

FIG. 10 is a schematic view illustrating steering of outboard motors by the steering angle adjustment process when the boat is controlled in the stay point mode according to the first example embodiment of the present invention.

FIG. 11 is a schematic view of steering of the outboard motors by the steering angle adjustment process when the boat is controlled in the stay point mode according to the first example embodiment of the present invention.

FIG. 12 is a block diagram illustrating a configuration of the steering system according to a second example embodiment of the present invention.

FIG. 13 is a schematic view illustrating steering of the outboard motors by the steering angle adjustment process at the start of the joystick mode according to the second example embodiment of the present invention.

FIG. 14 is a schematic view of steering of the outboard motors by the steering angle adjustment process at the start of the joystick mode according to the second example embodiment of the present invention.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

A first example embodiment will be described with reference to FIGS. 1 to 11. As shown in FIGS. 1 and 4, the boat 1A of the first example embodiment 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 an operator) that accepts an operation request 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 (an example of a sensor) to detect the turning of the boat body 10. The outboard motors 100P, 100S, the steering device 200, the controller 300, the position sensor 260, and the azimuth sensor 270 are elements of the boat control system 400A.

FIG. 1 and other figures to follow 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 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 thrust 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 elements or parts 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 the rotation axis Ad of the drive shaft 124, which is described below, extends in the upper-lower direction and the 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 throttle opening changes the flow rate of air supplied to the inside of the cylinder block, thus changing the output of the engine 120 (rotational 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 a read only memory (ROM) and a random access memory (RAN). 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 thrust by rotating. The propeller shaft 142 is a rod-shaped member and is arranged in a attitude 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 to linearly move the rack 163, e.g., the steering actuator 164P includes 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 operation requests 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 operation requests by the steering person to instruct the 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 operation requests by the steering person to instruct switching of the 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 operation requests 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 transition to the set point mode described below.

The joystick base 234 further includes 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 includes, e.g., an inertial measurement unit (IMU). The azimuth sensor 270 detects the azimuth of the boat body 10 and outputs the azimuth signal (an example of a detection signal) indicating the azimuth of the boat body 10.

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 operation requests 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 for executing the steering angle change 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. Based on these signals, the controller 300 outputs command signals to the ECUs 190P, 190S. 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 this 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. Based on these signals, 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.

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. Based on the received command signal, 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. 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. Based on the received command signal, 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. 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 request 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 joystick mode. The joystick mode start operation may be, e.g., a short press of the joystick button 240 by the steering person. When the joystick device 230 receives an operation request 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 joystick mode to the normal steering mode. The joystick mode deactivation operation may be, 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. Based on these signals, 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.

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 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 the joystick 232 is twisted. Based on the output command signals, the magnitude of thrust, the shift state, and the steering angle of the outboard motors 100P, 100S are controlled.

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 (an example of the holding control) 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 (an example of the holding control) 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.

Examples of procedures of controlling the outboard motors 100P, 100S by the boat control system 400A when the joystick mode start operation is executed will be described.

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 described above, when the joystick device 230 accepts the joystick mode start operation, the controller 300 switches the steering mode from the normal steering mode to the joystick mode.

Once steering in the joystick mode is started, the controller 300 determines whether the joystick 232 is in the default position (S110). This determination is based on the joystick signal received from the joystick sensor 250.

If the controller 300 determines that the joystick 232 is not in the default position, it proceeds to step S200. In step S200, 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 or twist amount of the joystick 232 in a direction in which the joystick 232 is tilted or twisted. Based on the output command signals, the magnitude of thrust, the shift state, and the steering angle of the outboard motors 100P, 100S are controlled. After completion of step S200, the controller 300 returns to step S110 and repeats the process.

If the controller 300 determines that the joystick 232 is in the default position, it will steer the outboard motors 100P, 100S to the default steering angle (S120). The default steering angle is the steering angle at which the lower units 130 of the outboard motors 100P, 100S are in a position facing each other. In other words, the steering angle of the first outboard motor 100P is +90° and that of the second outboard motor 100S is −90° (see the left figure in FIG. 7). At this time, the outboard motors 100P, 100S are idling and the engines 120 of both outboard motors 100P, 100S are rotating at such a low speed that the boat 1A will not start to move. With the steering angle set to the default steering angle as described above, the thrust generated by the two outboard motors 100P, 100S cancels each other out and the boat body 10 stays in place.

After step S120 is completed, the controller 300 receives the azimuth signal from the azimuth sensor 270 and calculates the turning speed of the boat body 10 (S130). In this specification, the turning of the boat body 10 to the starboard side, that is, rightward (clockwise) when viewed from above, is referred to as the turning in the positive direction, and the turning speed is expressed as a positive value. The turning of the boat body 10 to the port side, that is, leftward (counterclockwise) when viewed from above, is referred to as the turning in the negative direction, and the turning speed is expressed as a negative value (see FIG. 5).

After step S130 is completed, the controller 300 determines whether the joystick 232 is in the default position (S140). If the controller 300 determines that the joystick 232 is not in the default position, it controls the magnitude and direction of the thrust of the two outboard motors 100P, 100S so that the boat body 10 advances at a speed corresponding to the operation direction and operation amount of the joystick 232, as in step S200 (S210). After completion of step S210, the controller 300 returns to step S130 to repeat the process.

If the controller 300 determines that the joystick 232 is in the default position, it determines whether the turning speed calculated in step S130 is greater than or equal to a reference value RV1 (S150). The reference value RV1 being a positive value and the turning speed being greater than or equal to the reference value RV1 means that the boat body 10 is turning at a certain speed or more in the positive (clockwise) direction (see the left figure in FIG. 7).

If the turning speed is determined to be less than the reference value RV1 in step S150, the controller 300 determines whether the turning speed obtained in step S130 is less than a reference value RV2 (S220). The reference value RV2 being a negative value and the turning speed being less than or equal to the reference value RV2 means that the boat body 10 is turning at a certain speed or more in the negative (counterclockwise) direction (see the left figure in FIG. 8).

As mentioned above, when the joystick 232 is in the default position, the steering angles of the two outboard motors 100P, 100S are set to the default steering angle so that the thrust generated by the two outboard motors 100P, 100S cancels each other out. However, there are cases in which the boat body 10 turns unintentionally even though the joystick device 230 does not accept the operation request to turn the boat body 10 due to the mounting position of the outboard motors 100P, 100S, the shape of the boat body 10, or the effect of external disturbances such as wind or tide.

If it is determined in step S220 that the turning speed exceeds the reference value RV2, the controller 300 returns to step S130 and repeats the process. Here, since the boat body 10 is affected by disturbances such as wind and tide, it is rare for the boat body 10 to reach a completely stopped status. Therefore, if the turning speed value exceeds the reference value RV2 and is less than the reference value RV1, that is, if the turning speed is small enough to cause no problems in steering, the boat body 10 is considered not to be turning substantially and no special control is performed to correct the movement of the boat body 10. This avoids unnecessary control of the boat body 10 and makes steering more efficient.

If it is determined in step S150 that the turning speed is greater than or equal to the reference value RV1, the controller 300 proceeds to step S160. In step S160, the controller 300 steers the two outboard motors 100P, 100S in the positive (clockwise) direction, respectively (steering angle change process: see the right figure in FIG. 7). In other words, the steering angle of the first outboard motor 100P becomes slightly larger than +90°, and the steering angle of the second outboard motor 100S becomes slightly smaller than −90°. In this case, the thrust of the first outboard motor 100P can be decomposed into backward and rightward component forces, and the thrust of the second outboard motor 100S can be decomposed into forward and leftward component forces. Since the rightward component force of the first outboard motor 100P and the leftward component force of the second outboard motor 100S cancel each other out, a backward thrust is applied to the port side of the boat body 10 and a forward thrust is applied to the starboard side of the boat body 10 so that a force is applied to the boat body 10 to turn it in the negative (counterclockwise) direction. This cancels out the turning in the positive (clockwise) direction and stops the turning.

If it is determined in step S220 that the turning speed is less than or equal to the reference value RV2, the controller 300 proceeds to step S230. In step S230, the controller 300 steers the two outboard motors 100P, 100S in the negative (counterclockwise) direction, respectively (steering angle change process: see the right figure in FIG. 8). In other words, the steering angle of the first outboard motor 100P becomes slightly smaller than +90, and the steering angle of the second outboard motor 100S becomes slightly larger than −90°. In this case, the thrust of the first outboard motor 100P can be decomposed into forward and rightward component forces, and the thrust of the second outboard motor 100S can be decomposed into backward and leftward component forces. Since the rightward component force of the first outboard motor 100P and the leftward component force of the second outboard motor 100S cancel each other out, a forward thrust is applied to the port side of the boat body 10 and a backward thrust is applied to the starboard side of the boat body 10 so that a force is applied to the boat body 10 to turn it in the positive (clockwise) direction. This cancels out the turning in the negative (counterclockwise) direction and stops the turning.

During the steering angle change process of steps S160 and S230, the controller 300 controls the magnitude of the thrust generated by the two outboard motors 100P, 100S to remain constant. More specifically, the controller 300 keeps the throttle opening of each of the two outboard motors 100P, 100S constant, thus keeping the rotation speed of the engine 120 (rotation speed of the crankshaft 122) provided for each of the two outboard motors 100P, 100S constant. The magnitude of thrust of the two outboard motors 100P, 100S should be kept at the magnitude for idling. This can reduce or prevent the unintended movement of the boat body 10. In this steering angle change process, the controller 300 controls the change amount of the steering angle of each of the two outboard motors 100P, 100S so that it does not exceed a predetermined maximum value. This allows a quick transition to the next steering operation after the steering angle change process is completed.

After completion of step S160 or S230, the controller 300 receives the azimuth signal from the azimuth sensor 270 and calculates the turning speed of the boat body 10 (S170).

After calculating the turning speed, the controller 300 determines whether the boat body 10 has stopped turning (S180). For example, if the turning speed calculated in step S170 is greater than the reference value RV1 or less than the reference value RV2, the controller 300 determines that the boat body 10 has not stopped turning and returns to step S150 to repeat the process. If the turning speed exceeds the reference value RV2 and is less than the reference value RV1, the controller 300 considers that the boat body 10 has substantially stopped turning and terminates the steering angle change process. After completion of the steering angle change process, the controller 300 proceeds to step S190.

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 request is received, the controller 300 determines that the joystick mode has not been deactivated and returns to step S130 to repeat the process.

Examples of procedures of controlling the outboard motors 100P, 100S by the boat control system 400A when the boat 1A is controlled in the stay point mode will be described.

The procedure of controlling the outboard motors 100P, 100S by the boat control system 400A when the stay point mode start operation is performed when the boat 1A described above is controlled in the joystick mode will be described with reference to FIGS. 9 to 11. As described above, when the joystick device 230 accepts the stay point mode start operation, the controller 300 switches the steering mode to the stay point mode.

Once steering in the stay point mode is started, the controller 300 proceeds to step S310. In step S310, the controller 300 receives from the position sensor 260 a position signal corresponding to the position of the boat body 10 at the start of steering in the stay point mode and stores it as the target position. The controller 300 also receives from the azimuth sensor 270 an azimuth signal corresponding to the azimuth of the boat body 10 at the start of steering in the stay point mode and stores it as the target azimuth θ0 (an example of the initial azimuth). In this specification, the azimuth of the boat body 10 is expressed as the clockwise angle of the centerline C of the boat body 10 at the time of measurement relative to the reference direction DO. The reference direction DO is shown as a dashed line in FIGS. 10 and 11. The centerline CO of the boat body 10 at the time of measurement of the target azimuth θ0 is shown as a double-dashed line.

After completion of step S310, the controller 300 steers the steering angles of the outboard motors 100P, 100S to the default steering angle (S320).

After step S320 is completed, the controller 300 obtains the position and azimuth of the boat body 10 (S330). The controller 300 receives the position signal from the position sensor 260 and stores it as the current position. The controller 300 also receives the azimuth signal from the azimuth sensor 270 and stores it as the current azimuth θ.

After step S330 is completed, the controller 300 determines whether there is a deviation between the current azimuth θ obtained in step S330 and the target azimuth θ0 (S340).

If the controller 300 determines that there is no deviation between the current azimuth θ and the target azimuth θ0 in step S340, it then determines whether there is a deviation between the current position and the target position (S400). If the controller 300 determines in step S400 that there is no deviation between the current position and the target position, it returns to S330 and repeats the process.

If the controller 300 determines in step S400 that there is a deviation between the current position and the target position, the controller 300 outputs command signals to the throttle actuators 128P, 128S, the shift actuators 152P, 152S, and the steering actuators 164P, 164S to correct the deviation. Based on the output command signals, the magnitude of thrust, the shift state, and the steering angle of the outboard motors 100P, 100S are controlled so as to correct the position of the boat body 10 (S410). After completion of step S410, the controller 300 returns to step S330 to repeat the process.

If the controller 300 determines in step S340 that there is a deviation between the current azimuth θ and the target azimuth θ0, the controller 300 determines whether the value of (current azimuth θ−target azimuth θ0) is positive or not (S350). If the value of (current azimuth θ−target azimuth θ0) is positive, the boat body 10 is turning in the positive (clockwise) direction from the start of steering in the stay point mode (see the left figure in FIG. 10). If the value of (current azimuth θ−target azimuth θ0) is negative, the boat body 10 is turning in the negative (counterclockwise) direction from the start of steering in the stay point mode (see the left figure in FIG. 11).

If the value of (current azimuth θ−target azimuth θ0) is determined to be positive in step S350, the controller 300 proceeds to step S360. In step S360, the controller 300 steers the two outboard motors 100P, 100S in the positive (clockwise) direction, respectively (steering angle change process: see FIG. 10). As in step S160 above, this results in a backward thrust on the left side of the boat body 10 and a forward thrust on the right side. This force overcomes the force to turn the boat body 10 in the positive (clockwise) direction, and the boat body 10 turns in the negative (counterclockwise) direction and returns to the target azimuth θ0.

If it is determined in step S350 that the value of (current azimuth θ−target azimuth θ0) is negative, the controller 300 proceeds to step S420. In step S420, the controller 300 steers the two outboard motors 100P, 100S in the negative (counterclockwise) direction, respectively (steering angle change process: see FIG. 11). As in step S230 above, this results in a backward thrust on the left side of the boat body 10 and a forward thrust on the right side. This force overcomes the force to turn the boat body 10 in the negative (counterclockwise) direction, and the boat body 10 turns in the positive (clockwise) direction and returns to the target azimuth θ0.

As in steps S160 and S230 above, the controller 300 controls the output of the two outboard motors 100P, 100S (rotation speed of the crankshaft 122) to remain constant during the steering angle change process of steps S360 and S420. The controller 300 also controls the change amount of the steering angle of each of the two outboard motors 100P, 100S so that it does not exceed a predetermined maximum value.

After completion of step S360 or S420, the controller 300 again receives the azimuth signal from the azimuth sensor 270 and stores it as the current azimuth θ (S370). Next, the controller 300 determines whether the current azimuth θ obtained in step S370 matches the target azimuth θ0 (S380).

If it is determined in step S380 that the current azimuth θ does not match the target azimuth θ0, the controller 300 returns to step S350 and repeats the process. If it is determined in step S380 that the current azimuth θ becomes equal to the target azimuth θ0, the controller 300 proceeds to step S390. Even if the current azimuth θ and the target azimuth θ0 do not completely match, the controller 300 may be set to determine that the current azimuth θ substantially matches the target azimuth θ0 and proceed to the next step if the difference is slight enough to not affect steering.

In step S390, the controller 300 determines whether the stay point mode has been deactivated. If the controller 300 receives an operation signal from the joystick sensor 250 associated with the stay point mode deactivation operation conducted by the steering person, the controller 300 determines that the stay point mode has been deactivated and switches the steering mode to the joystick steering mode. If the operation signal associated with the stay point mode deactivation operation request is not received, the controller 300 determines that the stay point mode has not been deactivated and returns to step S330 to repeat the process.

As described above, the boat 1A in this 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 configured to be steered 180 degrees or more about a steering axis, the controller 300 configured or programmed to control the thrust and steering angle of the first outboard motor 100P and the second outboard motor 100S, the steering device 200 to accept the operation request to move the boat body 10 and output the operation signal to the controller 300, and the azimuth sensor 270 to detect a turning of the boat body 10 and output an azimuth signal to the controller 300, wherein the controller 300 is configured or programmed to perform, when the azimuth sensor 270 detects a turning of the boat body 10 in a status where the steering device 200 is not accepting an operation request to turn the boat body 10, a steering angle change process to change the steering angle of the first outboard motor 100P and second outboard motor 100S to cancel the turning of the boat body 10.

According to the above configuration, when the boat body 10 starts to turn in a way that is not intended by the steering person, the movement of the boat body 10 can be automatically corrected, making it easier to steer the boat as intended by the steering person.

In addition, the steering device 200 includes the joystick 232 and the joystick base 234 that accepts operation requests to switch on/off the joystick mode in which the joystick 232 is able to accept operation requests to move the boat body 10, and the controller 300 configured or programmed to perform the steering angle change process when the joystick base 234 accepts an operation request to switch the joystick mode from off to on.

When the joystick mode is switched from off to on, there may be cases where the boat body 10 turns in a way that is not intended by the steering person. The above configuration can be suitably applied to such cases.

The controller 300 terminates the steering angle change process when the azimuth sensor 270 detects that the boat body 10 has stopped turning.

This configuration makes it easy to set the timing for terminating the steering angle change process.

The steering angle change process is executed when the controller 300 is controlling the boat body 10 in the stay point mode to hold the boat body 10 in a specific orientation.

When a control is being performed in the stay point mode to hold the boat body 10 in a specific orientation, there may be cases where the boat body 10 turns in a way that is not intended by the steering person. The above configuration can be suitably applied to such cases.

The controller 300 stores the target azimuth θ0, which is the orientation of the boat body 10 when control in the stay point mode is started, and terminates the steering angle change process when the azimuth sensor 270 detects that the boat body 10 has returned to the target azimuth θ0 after the steering angle change process has started.

This configuration makes it easy to set the timing for terminating the steering angle change process.

Also, the controller 300 controls the magnitude of the thrust of the outboard motors 100P, 100S to remain constant during the steering angle change process.

This configuration can reduce or prevent the unintended movement of the boat body 10.

In the steering angle change process, the controller 300 changes the steering angle so that the steering angle does not exceed a predetermined maximum change amount of the steering angle.

This configuration allows the steering person to quickly proceed to the next steering operation after the steering angle change process has been completed.

A second example embodiment of the present invention will be described with reference to FIGS. 12 to 14. The boat 1B of the second example embodiment further includes a third outboard motor 100C (an example of 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. 13). 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, and an ECU 190C, as shown in FIG. 12. 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.

As in the first example embodiment, if it is determined in step S150 that the turning speed is greater than or equal to the reference value RV1, that is, if the boat body 10 is turning in the positive (clockwise) direction, the controller 300 proceeds to step S160. In step S160, the controller 300 steers the two outboard motors 100P, 100S in the negative direction, respectively (steering angle change process: see FIG. 13), as in the first example embodiment. At this time, the third outboard motor 100C is steered in the direction in which the boat body 10 is turning, i.e., in the positive (clockwise) direction. When the boat body 10 is turning in the positive (clockwise) direction, the water flow acts counterclockwise 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.

As in the first example embodiment, if the turning speed is determined to be less than the reference value RV2 in step S220, that is, if the boat body 10 is turning in the negative (counterclockwise) direction, the controller 300 proceeds to step S230. In step S230, the controller 300 steers the two outboard motors 100P, 100S in the positive direction, respectively, as in the first example embodiment (steering angle change process: see FIG. 14). At this time, the third outboard motor 100C is steered in the direction in which the boat body 10 is turning, i.e., in the negative (counterclockwise) direction. When the boat body 10 is turning in the negative (counterclockwise) direction, the water flow acts clockwise 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.

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

According to the example embodiment described above, the boat 1B includes the first outboard motor 100P, the second outboard motor 100S, and the third outboard motor 100C disposed between the first outboard motor 100P and the second outboard motor 100S, and the steering angle change process changes the steering angle of at least one of the first outboard motor 100P and the second outboard motor 100S.

In this way, when the boat 1B includes three outboard motors 100P, 100S, 100C, using the two outboard motors 100P, 100S on the outside in the steering angle change process can balance the positions of the two outboard motors 100P, 100S used in the steering angle change process, thus efficiently correcting the movement of the boat body 10.

In the steering angle change process, the controller 300 steers the third outboard motor 100C in the direction in which the boat body 10 is turning.

With this configuration, the third outboard motor 100C can act as resistance to the water flow acting against the boat body 10 when the boat body 10 is turning, thus quickly correcting the 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 steering angle change process is executed when a control is performed in the stay point mode as a holding control, but for example, the steering angle change process may be executed when a control is performed in the drift point mode as a holding control.

In the second example embodiment, the boat 1B includes 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 for the steering angle change process, e.g., the two outboard motors at both ends may be the first and second outboard motors used for the steering angle change process, or the two inner outboard motors may be the first and second outboard motors used for the steering angle change process. The two outboard motors located in a line symmetrical position with respect to the centerline of the boat body as the target axis may be 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 having three or more outboard motors.

In the second example embodiment, an example is shown in which the third outboard motor 100C is steered in the steering angle change process when a control is being performed in the joystick mode, but the third outboard motor may be steered in the steering angle change process during a holding control, such as a control in the stay point mode.

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.

BOAT CONTROL SYSTEM AND BOAT

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CPC

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