US20240239464A1

US20240239464A1 - Watercraft maneuvering system and watercraft including the watercraft maneuvering system

Info

Publication number: US20240239464A1
Application number: US18/411,093
Authority: US
Inventors: Yuhei SUZUKI; Ryo Nakanishi
Original assignee: Yamaha Motor Co Ltd
Current assignee: Yamaha Motor Co Ltd
Priority date: 2023-01-17
Filing date: 2024-01-12
Publication date: 2024-07-18
Also published as: JP2024101415A

Abstract

A watercraft maneuvering system includes a steering including a steering actuator and operable to change a steering angle to change a course of a watercraft, a steering angle sensor to detect the steering angle, and a steering controller configured or programmed to control the steering actuator according to an output signal of the steering angle sensor. The steering controller includes a calibration mode in which output signal values of the steering angle sensor respectively corresponding to opposite limits of the steering range of the steering are stored, and is configured or programmed to perform an automatic steering control operation to drive the steering actuator to operate the steering to a predetermined steering angle after storing the output signal values of the steering angle sensor respectively corresponding to the opposite limits of the steering range.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese Patent Application No. 2023-005380 filed on Jan. 17, 2023. The entire contents of this application are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to watercraft maneuvering systems, and watercraft including the watercraft maneuvering systems.

2. Description of the Related Art

US 2011/0166724 A1 discloses a watercraft which includes a steering wheel, an outboard motor, and a steering to steer the outboard motor. The steering includes a steering ECU (Electronic Control Unit), a steering actuator, and a steering angle sensor. The steering angle sensor detects the steering angle of the outboard motor. A target steering angle is set according to an operation angle of the steering wheel, and the steering ECU controls the steering actuator according to the target steering angle such that the outboard motor is pivoted leftward and rightward. The steering angle sensor is, for example, a potentiometer.

SUMMARY OF THE INVENTION

The inventors of example embodiments of the present invention described and claimed in the present application conducted an extensive study and research regarding a watercraft maneuvering system, such as the one described above, and in doing so, discovered and first recognized new unique challenges and previously unrecognized possibilities for improvements as described in greater detail below.
Calibration should be performed to preliminarily correlate the output signal of the steering angle sensor with a value of the steering angle in order to accurately detect the steering angle based on the output signal of the steering angle sensor. In US 2011/0166724 A1, there is no description of such calibration.
In US 2011/0166724 A1, calibration for the lateral movement and the bow turning of the watercraft by the operation of a joystick is described, but this is different from the calibration for the output signal of the steering angle sensor.
Example embodiments of the present invention provide watercraft maneuvering systems each including an arrangement to calibrate the output signal of a steering angle sensor, and watercraft including the watercraft maneuvering systems.
In order to overcome the previously unrecognized and unsolved challenges described above, an example embodiment of the present invention provides a watercraft maneuvering system including a steering including a steering actuator and operable to change a steering angle to change a course of a watercraft, a steering angle sensor to detect the steering angle, and a steering controller configured or programmed to control the steering actuator according to an output signal of the steering angle sensor. The steering controller includes a calibration mode in which output signal values of the steering angle sensor respectively corresponding to the opposite limits of the steering range of the steering are stored, and is configured or programmed to perform an automatic steering control operation to drive the steering actuator to operate the steering to a predetermined steering angle after storing the output signal values of the steering angle sensor respectively corresponding to the opposite limits of the steering range.
With this arrangement, the output signal values of the steering angle sensor respectively corresponding to the opposite limits of the steering range are stored such that the steering angle can be determined from the output signal of the steering angle sensor based on the stored output signal values. That is, the calibration can be performed to correlate the output signal of the steering angle sensor with the steering angle.
In addition, the steering is automatically steered to the predetermined steering angle after the output signal values of the steering angle sensor respectively corresponding to the opposite limits of the steering range are stored. Therefore, the steering controller can thereafter smoothly start the steering control operation.
In an example embodiment of the present invention, the watercraft maneuvering system further includes a steering operator to be operated by a user (an operator) to steer the watercraft, and an operation sensor to detect the operation of the steering operator. The steering controller is configured or programmed to adjust the steering angle of the steering to one of the opposite limits of the steering range and then to the other of the opposite limits by driving the steering actuator according to the output signal of the operation sensor during the calibration mode, and to drive the steering actuator irrespective of the output signal of the operation sensor during the automatic steering control operation.
With this arrangement, the user operates the steering operator to drive the steering actuator so as to adjust the steering angle of the steering to the one of the opposite limits and then to the other of the opposite limits of the steering range. Thus, the user can perform the calibration while checking or observing the operation of the steering. After the output signal values of the steering angle sensor respectively corresponding to the one of the opposite limits and the other of the opposite limits of the steering range are stored, the steering controller does not respond to the operation of the steering operator, but controls the steering to the predetermined steering angle by the automatic steering control operation. Therefore, an ordinary control operation can be smoothly started after the calibration.
In an example embodiment of the present invention, the steering controller is configured or programmed to store one of the output signal values of the steering angle sensor when it is detected that the steering angle of the steering reaches the one of the opposite limits of the steering range, and to store another output signal value of the steering angle sensor when it is detected that the steering angle of the steering reaches the other of the opposite limits of the steering range.
With this arrangement, the output signal values of the steering angle sensor are stored when the steering controller determines that the steering angle of the steering reaches the one of the opposite limits and the other of the opposite limits of the steering range. Thus, the output signal of the steering angle sensor can be reliably calibrated.
In an example embodiment of the present invention, the watercraft maneuvering system further includes a notifier to issue a notification when the steering controller determines that the steering angle of the steering reaches the one of the opposite limits of the steering range during the calibration mode and to issue a notification when the steering controller determines that the steering angle of the steering reaches the other of the opposite limits of the steering range during the calibration mode, and an input interface to be operated by the user to input a command in response to each of the notifications. The steering controller is configured or programmed to store the output signal values of the steering angle sensor when the command is inputted via the input interface in response to each of the notifications during the calibration mode.
With this arrangement, the steering controller determines that the steering angle of the steering reaches the one of the opposite limits and the other of the opposite limits of the steering range, and this is notified to the user. When the user operates interacts with the input interface to give the command, the output signal values of the steering angle sensor are stored. Thus, the output signal values of the steering angle sensor are stored after the determination by the steering controller and checking by the user, so that the output signal of the steering angle sensor can be more reliably calibrated.
The output signal values of the steering angle sensor may be stored based on the determination by the steering controller without the notifications to the user or the input of the command by the user.
In an example embodiment of the present invention, the range of a target steering angle (control steering angle range) to be used when the steering controller controls the steering actuator is a steering angle range within the steering range between the one of the opposite limits and the other of the opposite limits.
With this arrangement, the range of the target steering angle, i.e., the control steering angle range, to be set by the steering controller is narrower than the steering range, and is within the steering range. The control steering angle range is thus defined for various reasons. For example, the control steering angle range may be thus set to prevent interference between adjacent propulsion devices.
In an example embodiment of the present invention, the predetermined steering angle is within the range of the target steering angle (control steering angle range).
With this arrangement, the steering is controlled to the steering angle within the control steering angle range by the automatic steering control operation at the end of the calibration. Therefore, the ordinary control operation can be thereafter smoothly started.
In an example embodiment of the present invention, the steering actuator includes a hydraulic actuator including a hydraulic cylinder and an electric pump to supply a hydraulic oil into the hydraulic cylinder.
In an example embodiment of the present invention, the steering steers an outboard motor attached to a hull of the watercraft.
Another example embodiment of the present invention provides a watercraft maneuvering system including a steering including a steering actuator and operable to change a steering angle to change a course of a watercraft, and a steering controller configured or programmed to control the steering actuator according to an output signal of a steering angle sensor. The steering controller is configured or programmed to perform an automatic steering control operation to drive the steering actuator to operate the steering to a predetermined steering angle at the end of a calibration mode to calibrate the output signal of the steering angle sensor.
With this arrangement, the steering is automatically steered to the predetermined steering angle at the end of the calibration. Therefore, the steering controller can thereafter smoothly start the steering control operation.
Another further example embodiment of the present invention provides a watercraft including a hull, and a watercraft maneuvering system provided on the hull and including any of the aforementioned features.
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 plan view showing an exemplary construction of a watercraft mounted with a watercraft maneuvering system according to an example embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a watercraft maneuvering system by way of example.

FIG. 3 is a diagram showing the structure of a steering by way of example.

FIG. 4 is a block diagram showing a configuration of a steering controller by way of example.

FIG. 5 is a diagram for describing a relationship between a steering range of an outboard motor and a control steering angle range.

FIG. 6 is a flowchart for describing a procedure for calibration of steering angle sensors, a process to be performed by steering controllers, and the like.

FIGS. 7A to 7F are schematic plan views for describing a steering operation to be performed for the calibration of the steering angle sensors.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

FIG. 1 is a plan view showing an exemplary construction of a watercraft 1 mounted with a watercraft maneuvering system 100 according to an example embodiment of the present invention. The watercraft 1 includes a hull 2 and outboard motors OM as exemplary propulsion devices. The outboard motors OM are attached to the stern 3 of the hull 2. In the present example embodiment, two outboard motors OM are disposed side by side transversely of the hull 2 and attached to the stern 3. For discrimination between the two outboard motors OM, one of the outboard motors OM disposed rightward relative to the other outboard motor OM is referred to as “starboard-side outboard motor OMs” and the other outboard motor OM disposed leftward relative to the one outboard motor OM is referred to as “port-side outboard motor OMp.” A starboard-side steering STGs and a port-side steering STGp are provided on the stern 3 so as to steer the starboard-side outboard motor OMs and the port-side outboard motor OMp, respectively, leftward and rightward. The starboard-side steering STGs and the port-side steering STGp are generally referred to as “steerings STG.” The steerings STG are devices each operable to change the direction of a propulsive force generated by the corresponding outboard motor OM leftward and rightward. The steerings STG are each operable to pivot (turn) the body of the corresponding outboard motor OM leftward and rightward with respect to the hull 2 such that a steering angle is changed to change the course of the watercraft 1. In the present example embodiment, the steering angle is defined as the angle of the propulsive force of the outboard motor OM with respect to the anteroposterior direction of the hull 2. That is, the steering angle is an angle defined by the direction of the propulsive force of the outboard motor OM with respect to a center line 2 a extending anteroposteriorly of the hull 2 as seen in a plan view. In the present example embodiment, the starboard-side outboard motor OMs is disposed on the right side of the center line 2 a, and the port-side outboard motor OMp is disposed on the left side of the center line 2 a.
A usable space 4 for passengers is provided inside the hull 2. A helm seat 5 is provided in the usable space 4. A steering wheel 6, a remote control lever 7, a joystick 8, a gauge 9 (display panel) and the like are provided in association with the helm seat 5. The steering wheel 6 is an example of the steering operator to be operated by a user (an operator) to change the course of the watercraft 1. The remote control lever 7 is an operator to be operated by the user to change the magnitudes (outputs) and the directions (forward or reverse directions) of the propulsive forces of the respective outboard motors OM, and corresponds to an acceleration operator. In the present example embodiment, the remote control lever 7 includes two remote control levers 7 s, 7 p for the two outboard motors OMs, OMp. The joystick 8 is an operator to be operated instead of the steering wheel 6 and the remote control lever 7 by the user to maneuver the watercraft. The joystick 8 is another example of a steering operator. The gauge 9 is a display device on which information regarding watercraft maneuvering is displayed, and is an example of a notifier.
FIG. 2 is a diagram showing the configuration of the watercraft maneuvering system 100 provided in the watercraft 1 by way of example.
The outboard motors OM may each be an engine outboard motor or an electric outboard motor. In FIG. 2 , the outboard motors OM are each illustrated as an engine outboard motor by way of example. The outboard motors OM each include an outboard motor controller (electronic control unit) 21, an engine 23, a shift mechanism 24, a propeller 20, a power generator 30 and the like. The power generator 30 is driven by the engine 23. The power generator 30 supplies electric power to the electric components of the outboard motor OM, and charges a battery 15 provided on the hull 2 (see FIG. 1 ). Typically, separate batteries 15 are provided for the respective outboard motors OM.
Power generated by the engine 23 is transmitted to the propeller 20 via the shift mechanism 24. The shift mechanism 24 is configured to select a shift position from a forward shift position, a reverse shift position, and a neutral shift position. With the shift position set to the forward shift position, the propeller 20 is rotated in a forward rotation direction by the transmission of the rotation of the engine 23 such that the outboard motor OM is brought into a forward drive state to generate a forward propulsive force. With the shift position set to the reverse shift position, the propeller 20 is rotated in a reverse rotation direction by the transmission of the rotation of the engine 23 such that the outboard motor OM is brought into a reverse drive state to generate a reverse propulsive force. With the shift position set to the neutral shift position, the power transmission between the engine 23 and the propeller 20 is interrupted such that the outboard motor OM is brought into an idling state.
The outboard motors OM each further include a throttle actuator 27 and a shift actuator 28 which are controlled by the outboard motor controller 21. The throttle actuator 27 includes an electric actuator (typically including an electric motor) that actuates a throttle valve (not shown) of the engine 23. The shift actuator 28 is an actuator (typically including an electric motor) that actuates the shift mechanism 24.
The steerings STG each include a steering controller 22 and a steering actuator 25. The steering controller 22 drives the steering actuator 25. The steering actuator 25 is a drive source of the steering STG, and typically includes an electric motor. The steering actuator 25 may include a ball screw mechanism to be driven by the electric motor. Alternatively, the steering actuator 25 may be a hydraulic actuator including a hydraulic cylinder to which a hydraulic oil is supplied by a pump (electric pump) driven by the electric motor.
In the present example embodiment, the steerings STG are each configured as a separate unit from the corresponding outboard motor OM, and attached to the stern 3. Alternatively, the steerings STG may be each unified with the corresponding outboard motor OM, and incorporated in the outboard motor OM. Further, a portion (e.g., the steering controller 22) of the steering STG may be incorporated in the body of the corresponding outboard motor OM. A steering angle sensor 29 to detect the steering angle is incorporated in the steering STG. The steering angle sensor 29 may be a position sensor to detect the position of a movable portion of the steering actuator 25. Alternatively, the steering angle sensor 29 may be a position sensor to detect the position of a movable portion of a link mechanism (not shown) which transmits the drive force of the steering actuator 25 to the outboard motor OM. Thus, the steering angle sensor 29 outputs a signal indicating the steering angle of the outboard motor OM. The position sensor may be a noncontact magnetic sensor including, for example, a Hall device and a magnet.
The steering wheel 6 is configured to be rotatable about its rotation axis. The steering wheel 6 is a steering operator having a limitless rotation operation range with no operation range limits. An operation speed sensor 12 to detect the speed of the rotation operation of the steering wheel 6 (the operation speed of the steering wheel 6) is provided in association with the steering wheel 6. The operation speed sensor 12 is an exemplary operation amount sensor to detect the operation amount of the steering wheel 6. The operation speed sensor 12 detects an operation amount per unit time as the operation speed of the steering wheel 6, and generates a signal indicating the operation speed. The operation speed sensor 12 is an example of the operation sensor to detect the operation of the steering wheel 6. The output signal of the operation speed sensor 12 is inputted to a helm controller 16. In association with the rotation shaft of the steering wheel 6, a brake 13 (typically, an electromagnetic brake) is provided as a rotation restricting device that restricts the rotation of the steering wheel 6. The brake 13 is controlled by the helm controller 16 to restrict the rotation of the rotation shaft of the steering wheel 6 to thus restrict the rotation of the steering wheel 6.
As described above, the steering wheel 6 has the limitless rotation operation range, and is limitlessly rotatable leftward and rightward. On the other hand, the steering ranges of the outboard motors OM each have a mechanical limitation, i.e., each have a right steering limit and a left steering limit. Therefore, when the steering angles of the outboard motors OM each correspond to the right steering limit or the left steering limit, the helm controller 16 actuates the brake 13 to restrict the rotation of the steering wheel 6. Thus, the user who operates the steering wheel 6 can recognize, through tactile feedback from the steering wheel 6, that the steering angles of the outboard motors OM reach either of the steering limits. The right steering limit and the left steering limit of the steering range of each of the outboard motors OM to be steered by the steerings STG are often set inward of the mechanical steering limits of the outboard motor OM (closer to a neutral steering angle position).
The two remote control levers 7 s, 7 p to be operated by the user are provided in a pivotally operable manner in a remote control unit 17. The remote control unit 17 further includes two operation position sensors 19 s, 19 p (hereinafter sometimes referred to generally as “operation position sensors 19”) that respectively detect the operation positions of the remote control levers 7 s, 7 p. The output signals of the operation position sensors 19 are inputted to two remote control ECUs (Electronic Control Units) 51 s, 51 p. The two remote control ECUs 51 s, 51 p (hereinafter sometimes referred to generally as “remote control ECUs 51”) are provided in association with the two outboard motors OMs, OMp, respectively.
The outboard motor controllers 21 of the outboard motors OM and the steering controllers 22 of the steerings STG are connected to an outboard motor control network 56. Further, the helm controller 16 and the remote control ECUs 51 are connected to the outboard motor control network 56. The outboard motor control network 56 includes a communication line 57 that connects together the two steering controllers 22 respectively provided in the two steerings STGs, STGp to define a ring-shaped network as a whole. The outboard motor controllers 21 each monitor the operation state of the corresponding engine 23 and, for example, periodically output information about the operation state to the outboard motor control network 56. The information about the operation state includes at least information indicating whether the engines 23 are operating or out of operation. For example, the outboard motor controllers 21 are each able to determine the operation state of the corresponding engine 23 based on information about the rotation speed of the engine 23.
The helm controller 16 applies the operation speed detected by the operation speed sensor 12 to the steering controllers 22 via the outboard motor control network 56. The steering controllers 22 each control the corresponding steering actuator 25 according to the operation speed applied from the helm controller 16. The steering controllers 22 may each output the steering angle of the corresponding outboard motor OM detected by the corresponding steering angle sensor 29 or a target steering angle (to be described below) to the outboard motor control network 56. The steering controllers 22 may each apply a helm lock command to the helm controller 16 when the steering angle of the corresponding outboard motor OM reaches either of the steering limits (specifically, limits of a control steering angle range to be described below). Upon reception of the helm lock command from the steering controller 22, the helm controller 16 actuates the brake 13 to restrict the rotation of the steering wheel 6.
The steering controllers 22 may each apply the helm lock command to the helm controller 16, for example, when the target steering angle (to be described below) has a value corresponding to either of the steering limits. Further, the steering controllers 22 may each apply the helm lock command to the helm controller 16, when the steering angle (actual steering angle) detected by the corresponding steering angle sensor 29 has the value corresponding to either of the steering limits. The helm lock command is exemplary steering angle information indicating that the steering angle of the outboard motor OM corresponds to either of the steering limits.
Instead of the steering controllers 22 each outputting the helm lock command, the helm controller 16 may actuate the brake 13 according to the target steering angle or the actual steering angle appearing on the outboard motor control network 56. That is, the helm controller 16 may be configured to actuate the brake 13 to restrict the rotation of the steering wheel 6 when the target steering angle or the actual steering angle has a value corresponding to either of the steering limits.
It is noted that, in a calibration mode to be described below, the aforementioned process for the actuation of the brake 13 is not performed. In the calibration mode, the brake 13 is not actuated, but the limitless rotation operation of the steering wheel 6 is permitted.
The remote control ECUs 51 each generate a propulsive force command according to the position of the corresponding remote control lever 7 detected by the corresponding operation position sensor 19, and each supply the propulsive force command to the corresponding outboard motor controller 21 via the outboard motor control network 56. The propulsive force command includes a shift command and an output command. The outboard motor controllers 21 each control the corresponding shift actuator 28 based on the shift command to control the shift position of the corresponding shift mechanism 24. The outboard motor controllers 21 each control the corresponding throttle actuator 27 based on the output command to thus control the output (rotation speed) of the corresponding engine 23.
A main controller 50 is connected to the remote control ECUs 51 via an onboard network 55 (CAN: Control Area Network). A joystick unit 18 is connected to the main controller 50. The joystick unit 18 includes the joystick 8, which can be inclined forward, backward, leftward, and rightward (i.e., in all 360-degree directions) and can be pivoted (twisted) about its axis. Though not shown, the joystick unit 18 includes an inclination sensor to detect the inclination operation direction and the inclination operation amount of the joystick 8, and a pivot sensor to detect the pivot operation direction and the pivot operation amount of the joystick 8. The inclination sensor includes an anteroposterior component sensor to detect the anteroposterior inclination component of the joystick 8, and a lateral component sensor to detect the lateral inclination component of the joystick 8. The detection values of the inclination sensor and the pivot sensor are inputted to the main controller 50.
In this example, the joystick unit 18 further includes a plurality of operation buttons. The operation buttons include a joystick button 180 and holding mode setting buttons 181 to 183. The joystick button 180 is an operator to be operated by the user to select a control mode (watercraft maneuvering mode) using the joystick 8, i.e., a joystick mode. The holding mode setting buttons 181 to 183 are operation buttons to be operated by the user to select position/azimuth holding control modes (exemplary automatic watercraft maneuvering modes). More specifically, the holding mode setting button 181 is operated to select a fixed point holding mode (Stay Point™) in which the position and the bow azimuth (or the stern azimuth) of the watercraft are maintained. The holding mode setting button 182 is operated to select a position holding mode (Fish Point™) in which the position of the watercraft is maintained but the bow azimuth (or the stern azimuth) of the watercraft is not maintained. The holding mode setting button 183 is operated to select an azimuth holding mode (Drift Point™) in which the bow azimuth (or the stern azimuth) of the watercraft is maintained but the position of the watercraft is not maintained.
Further, a GPS (Global Positioning System) receiver 52, an azimuth sensor 53, an application switch panel 60 and the like are connected to the onboard network 55. The GPS receiver 52 is an exemplary position detecting device. The GPS receiver 52 detects the position of the watercraft 1 by receiving radio waves from an artificial satellite orbiting the earth, and outputs position data indicating the position of the watercraft 1 and speed data indicating the moving speed of the watercraft 1. The main controller 50 acquires the position data and the speed data, which are used to control and display the position and/or the azimuth of the watercraft 1. The GPS is a specific example of a GNSS (Global Navigation Satellite System). The azimuth sensor 53 detects the azimuth of the watercraft 1, and generates azimuth data which is used by the main controller 50.
The application switch panel 60 includes a plurality of function switches 61 to be operated to apply predefined function commands. For example, the function switches 61 may include switches for automatic watercraft maneuvering commands. More specifically, a command for a bow holding mode (Heading Hold) in which an automatic steering operation is performed to maintain the bow azimuth during forward sailing may be assigned to one of the function switches 61, and a command for a straight sailing holding mode (Course Hold) in which an automatic steering operation is performed to maintain the bow azimuth and a straight course during forward sailing may be assigned to another of the function switches 61. Further, a command for a checkpoint following mode (Track Point) in which an automatic steering operation is performed to follow a course (route) passing through specified checkpoints may be assigned to further another of the function switches 61, and a command for a pattern sailing mode (Pattern Steer) in which an automatic steering operation is performed to follow a predetermined sailing pattern (zig-zag pattern, spiral pattern or the like) may be assigned to still another of the function switches 61. These modes are exemplary automatic watercraft maneuvering modes.
Further, the gauge 9 is connected to the onboard network 55. The gauge 9 is a display that displays various information for maneuvering the watercraft. The gauge 9 can communicate, for example, with the main controller 50, the remote control ECUs 51 and the like. Thus, the gauge 9 can display the operation states of the outboard motors OM, the position and/or the azimuth of the watercraft 1 and other information. The gauge 9 may include an input device 10 such as a touch panel and buttons. The input device 10 may be operated by the user to set various settings and provide various commands such that operation signals are outputted to the onboard network 55. An additional network other than the onboard network 55 may be provided to transmit display control signals related to the gauge 9.
The main controller 50 includes a processor and a memory (both not shown), and is configured or programmed so that the processor executes a program stored in the memory to perform a plurality of functions. The main controller 50 includes a plurality of control modes. The control modes of the main controller 50 are classified into an ordinary watercraft maneuvering mode, the joystick mode, or the automatic watercraft maneuvering mode in terms of the operation system.
The ordinary watercraft maneuvering mode is a control mode in which a steering control operation is performed according to the operation of the steering wheel 6 and a propulsive force control operation is performed according to the operation of the remote control lever 7. In the present example embodiment, the ordinary watercraft maneuvering mode is a default control mode of the main controller 50. In the steering control operation, specifically, the steering controllers 22 each drive the corresponding steering actuator 25 according to an operation speed signal generated by the operation speed sensor 12 according to the operation of the steering wheel 6 or a steering angle command (specifically, a target steering angle command) generated by the corresponding remote control ECU 51. Thus, the outboard motors OM are steered leftward and rightward to change the directions of the propulsive forces to be applied to the hull 2 leftward and rightward. In the propulsive force control operation, specifically, the outboard motor controllers 21 each drive the corresponding shift actuator 28 and the corresponding throttle actuator 27 according to the propulsive force command (the shift command and the output command) applied thereto by the corresponding remote control ECU 51. Thus, the shift positions of the outboard motors OM are each set to the forward shift position, the reverse shift position, or the neutral shift position, and the engine outputs (specifically, the engine rotation speeds) are changed.
The joystick mode is a control mode in which the steering control operation and the propulsive force control operation are performed according to the operation signal of the joystick 8. In the joystick mode, the steering control operation and the propulsive force control operation are performed according to the operation of the joystick 8. That is, the main controller 50 applies the steering angle command and the propulsive force command to the remote control ECUs 51 according to the operation of the joystick 8. The remote control ECUs 51 each apply the steering angle command to the corresponding steering controller 22, and each apply the propulsive force command to the corresponding outboard motor controller 21.
The automatic watercraft maneuvering mode is a control mode in which the steering control operation and/or the propulsive force control operation are automatically performed by the functions of the main controller 50 and the like without the operation of the steering wheel 6, the remote control lever 7, and the joystick 8. That is, an automatic watercraft maneuvering operation is performed. The automatic watercraft maneuvering operation includes an automatic watercraft maneuvering operation to be performed on a sailing basis during sailing, and an automatic watercraft maneuvering operation to be performed on a position/azimuth holding basis to maintain one or both of the position and the azimuth of the watercraft 1. Examples of the automatic watercraft maneuvering operation on the sailing basis include the automatic steering operations to be selected by operating the function switches 61. Examples of the automatic watercraft maneuvering operation on the position/azimuth holding basis include watercraft maneuvering operations to be performed in the fixed point holding mode, the position holding mode, and the azimuth holding mode which are respectively selected by operating the holding mode setting buttons 181, 182, and 183. In the automatic watercraft maneuvering mode, the main controller 50 generates the steering angle command and the propulsive force command by using the position information generated by the GPS receiver 52 and/or the azimuth information generated by the azimuth sensor 53. In the automatic watercraft maneuvering mode, the main controller 50 applies the steering angle command and the propulsive force command to the remote control ECUs 51, and the remote control ECUs 51 each apply the steering angle command to the corresponding steering controller 22 and apply the propulsive force command to the corresponding outboard motor controller 21 as in the joystick mode.
In the joystick mode and the automatic watercraft maneuvering mode, the helm controller 16 does not need to supply the output of the operation speed sensor 12 to the outboard motor control network 56. Alternatively, the steering controllers 22 may be each configured or programmed so as not to respond to the operation speed signal outputted to the outboard motor control network 56 by the helm controller 16 when the steering angle command is applied from the corresponding remote control ECU 51.
FIG. 3 is a diagram showing the structure of the steering STG by way of example. In this example, the steerings STG are hydraulic steerings. The steerings STG each include a hydraulic pump 45, an electric motor M that drives the hydraulic pump 45, a hydraulic cylinder 40, and a hydraulic circuit 46 that causes a hydraulic oil to flow between the hydraulic pump 45 and the hydraulic cylinder 40. The hydraulic cylinder 40 is a dual action cylinder, and includes a cylinder tube 47, a piston 43 provided in the cylinder tube 47, and a piston rod 44 fixed to the piston 43 and extending to opposite sides of the piston 43.
The cylinder tube 47 and the piston rod 44 each extend laterally. The opposite end portions of the piston rod 44 are connected to the swivel bracket 33 of the corresponding outboard motor OM. The inside space of the cylinder tube 47 is partitioned into a right cylinder chamber 41 and a left cylinder chamber 42 by the piston 43. The cylinder tube 47 is linked to the steering arm 34 of the outboard motor OM. The cylinder tube 47 is guided by the piston rod 44 to be movable leftward and rightward. Thus, the steering arm 34 of the outboard motor OM is moved leftward and rightward to thus pivot (steer) the outboard motor OM about its steering shaft 35 leftward and rightward.
The hydraulic circuit 46 is connected to the right cylinder chamber 41 and the left cylinder chamber 42. The electric motor M is rotatable in normal and reverse rotation directions, and the hydraulic pump 45 pumps the hydraulic oil into one of the two cylinder chambers 41, 42 according to the rotation direction of the electric motor M. Thus, the cylinder tube 47 is moved leftward or rightward so that the one cylinder chamber has a greater volume and the other cylinder chamber has a smaller volume.
The electric motor M and the hydraulic pump 45 define the electric pump. Further, the steering actuator 25 of the steering STG includes a hydraulic actuator defined by the electric motor M, the hydraulic pump 45, the hydraulic circuit 46, and the hydraulic cylinder 40. The steering angle sensor 29 of the steering STG may be operable to detect the lateral position of the cylinder tube 47. Alternatively, the steering angle sensor 29 may be operable to detect the rotational position of the steering arm 34. Thus, the steering angle sensor 29 detects the steering angle of the outboard motor OM.
A bypass oil channel 46 a through which the left and right cylinder chambers 41, 42 communicate with each other, and a relief valve 46 b that opens and closes the bypass oil channel 46 a are preferably provided in the hydraulic circuit 46. By manually opening the relief valve 46 b, the left and right cylinder chambers 41, 42 communicate with each other through the bypass oil channel 46 a. Therefore, the user can manually steer the outboard motor OM leftward and rightward by applying an external force to the outboard motor OM. By manually closing the relief valve 46 b, the user can maintain the outboard motor OM at a desired steering angle. Thus, a manual operation mechanism for an emergency can be provided by the relief valve 46 b and the like.
FIG. 4 is a block diagram showing the configuration of the steering controller 22 by way of example. The steering controller 22 includes a processing unit 65 and a drive circuit 66. The processing unit 65 includes a processor 65 a and a memory 65 b. The processing unit 65 is configured or programmed so that the processor 65 a executes a program stored in the memory 65 b to perform a plurality of functions. Specifically, the processing unit 65 is configured or programmed to function as a feedback control portion 70 and the like.
The feedback control portion 70 feedback-controls the steering actuator 25 (more specifically, the electric motor M) based on the output signal of the steering angle sensor 29 (operation speed signal) so as to achieve the target steering angle.
The feedback control portion 70 functions as a target steering angle computation portion 71, a deviation computation portion 72, a PID (Proportional Integral Differential) control portion 73, and a PWM (Pulse Width Modulation) signal generation portion 74. The target steering angle computation portion 71 computes the target steering angle based on the operation speed signal applied from the helm controller 16. Specifically, the target steering angle computation portion 71 computes the target steering angle by summing operation speed signals. An initial value for the summation is the steering angle detected by the steering angle sensor 29. The deviation computation portion 72 computes the deviation of the steering angle (actual steering angle) detected by the steering angle sensor 29 from the target steering angle. The target steering angle to be used may be the target steering angle computed by the target steering angle computation portion 71, or may be the target steering angle included in the steering angle command applied from the corresponding remote control ECU 51. The PID control portion 73 performs a proportional integral differential operation on the deviation computed by the deviation computation portion 72 to generate a control value to reduce the deviation. The PWM signal generation portion 74 generates a PWM signal having a duty ratio according to the control value. The drive circuit 66 is driven based on the PWM signal generated by the PWM signal generation portion 74.
The drive circuit 66 includes an H-type bridge circuit connected to the battery 15 (also see FIG. 2 ) which is charged by the power generator 30 provided in the corresponding outboard motor OM. Two batteries 15 may be provided as corresponding to the two outboard motors OM. The H-type bridge circuit of the drive circuit 66 includes two series circuits each including an upper arm switching device U1, U2 and a lower arm switching device L1, L2, and the two series circuits are connected in parallel to the battery 15. The switching devices U1, U2, L1, L2 each typically include a semiconductor switch such as a power transistor. Two terminals of the electric motor M are respectively connected to a node N1 located between a pair of switching devices U1 and L1 of a first series circuit and a node N2 located between a pair of switching devices U2 and L2 of a second series circuit. The electric motor M is, for example, a DC motor (direct current motor). The switching devices U1, U2, L1, L2 are switched by the PWM signal generated by the PWM signal generation portion 74 such that a voltage is applied to the electric motor M according to the duty ratio of the PWM signal.
When the electric motor M is driven in the forward rotation direction, for example, the lower arm switching device L1 of the first series circuit and the upper arm switching device U2 of the second series circuit are maintained in an OFF state. Then, the upper arm switching device U1 of the first series circuit and the lower arm switching device L2 of the second series circuit are turned on and off by the PWM signal. When the electric motor M is driven in the reverse rotation direction, the upper arm switching device U1 of the first series circuit and the lower arm switching device L2 of the second series circuit are maintained in an OFF state. Then, the lower arm switching device L1 of the first series circuit and the upper arm switching device U2 of the second series circuit are turned on and off by the PWM signal.
Thus, the drive circuit 66 is driven by the PWM signal having the duty ratio according to the deviation (steering angle deviation) of the actual steering angle from the target steering angle such that the voltage is applied to the electric motor M to reduce the steering angle deviation. Thus, the steering angle of the outboard motor OM is adjusted to the target steering angle. That is, the steering actuator 25 is feedback-controlled so that the actual steering angle detected by the steering angle sensor 29 approaches the target steering angle.
An electric current sensor 68 (electric current detection circuit) detects electric current (motor current) supplied from the drive circuit 66 to the electric motor M. The output signal of the electric current sensor 68 is inputted to the processing unit 65. The processing unit 65 can determine the motor current based on the output signal of the electric current sensor 68. The processing unit 65 may monitor the motor current and, as required, limit the duty ratio of the PWM signal to limit the voltage to be applied to the electric motor M.
FIG. 5 is a diagram for describing a relationship between the steering range of the outboard motor OM and the control steering angle range (the range of the target steering angle). The steering range of the outboard motor OM is a steering angle range in which the outboard motor OM can be mechanically steered. That is, the steering of the outboard motor OM is mechanically restricted between steering angles at the opposite limits of the steering range of the outboard motor OM. The control steering angle range in which the target steering angle is set can be defined within the steering range of the outboard motor OM. Typically, the control steering angle range is narrower than the steering range of the outboard motor OM. The rightward limit of the control steering angle range is located inward (leftward) of the rightward limit of the steering range of the outboard motor OM, and the leftward limit of the control steering angle range is located inward (rightward) of the steering range of the outboard motor OM. Where two or more outboard motors OM are disposed side by side, for example, the control steering angle range is set narrower than the steering range in order to prevent the interference between the outboard motors OM.
For example, it is herein assumed that, with the steering angle defined as zero at the neutral steering angle position, the steering angle is positive when the rear end of the outboard motor OM is located rightward with respect to the neutral steering angle position, and the steering angle is negative when the rear end of the outboard motor OM is located leftward with respect to the neutral steering angle position.
In this case, the steering range is such that the steering angle θ is −α≤θ≤α (α>0, e.g., α is about 38 degrees), and the control steering angle range is such that the steering angle θ is −β≤θ≤B (α>β>0, e.g., β is about 30 degrees).
FIG. 6 is a flowchart for describing a procedure to perform calibration of the steering angle sensors 29, a process to be performed by the steering controllers 22, and the like. The control mode of the steering controllers 22 includes, in addition to an ordinary control mode, a calibration mode in which output signal values of each of the steering angle sensors 29 of the steerings STG respectively corresponding to the rightward limit and the leftward limit of the steering range of the corresponding outboard motor OM are stored in the memory 65 b (see FIG. 4 ). By thus storing the output signal values of the steering angle sensor 29 respectively corresponding to the opposite limits of the steering range for the calibration, the steering controller 22 can compute the steering angle of the outboard motor OM based on the output signal of the steering angle sensor 29. In the calibration mode, the calibration is performed to calibrate the output signals of the steering angle sensors 29. The calibration is typically performed by a boat builder or a boat dealer when the watercraft 1 is assembled or is subjected to a maintenance operation.
The steering controllers 22 can be switched into the calibration mode, for example, by inputting a predetermined calibration start command from the input device 10 of the gauge 9. In the calibration mode, the steering controllers 22 do not perform the feedback control, but perform a feedforward control to drive the steering actuators 25 according to the output signal of the operation speed sensor 12. Before completion of the calibration, it is impossible to compute the steering angles based on the output signals of the steering angle sensors 29. Therefore, the steering controllers 22 neither compute the target steering angles nor output the steering angle information to the outboard motor control network 56. Therefore, the brake 13 is not actuated, so that the rotation of the steering wheel 6 is not restricted.
After the calibration mode is started, an instruction indicating that the steering wheel 6 should be operated to steer the outboard motors OM to one of the opposite limits of the steering range is displayed on the gauge 9 (Step S1). Following this instruction, the user rotates the steering wheel 6 in one of leftward and rightward directions (e.g., rightward). Then, one of the steering actuators 25 for one of the outboard motors OM located on a side corresponding to the operation direction of the steering wheel 6 is actuated such that the one outboard motor OM is steered to the one limit of the steering range by the corresponding steering STG (Step S2).
For example, as shown in FIG. 7A, it is herein assumed that the port-side and starboard-side outboard motors OM are each located at the neutral steering angle position at the start of the calibration mode. When the steering wheel 6 is rotated rightward after the start of the calibration mode, the starboard-side outboard motor OMs is steered to the rightward limit of the steering range. When the steering angle of the outboard motor OMs reaches the rightward limit of the steering range, as shown in FIG. 7B, the steering of the outboard motor OMs is mechanically restricted and, therefore, the output signal value of the corresponding steering angle sensor 29 does not change. Further, the load of the electric motor M of the outboard motor OMs is increased, thus correspondingly increasing the motor current. Based on this, the corresponding steering controller 22 determines that the steering angle of the outboard motor OMs reaches the one limit (here, the rightward limit) of the steering range (Step S3), and stores the output signal value of the steering angle sensor 29 outputted at this time as an output signal value corresponding to the one limit (rightward limit) of the steering range of the outboard motor OMs in the memory 65 b (Step S6). In the present example embodiment, when the steering angle of the outboard motor OMs reaches the one limit (rightward limit) of the steering range, this information (notification) is displayed on the gauge 9 to be received by the user (Step S4). The user who receives this information (notification) operates the input device 10 to input a command (Step S5). Upon reception of the command, the steering controller 22 stores the output signal value of the steering angle sensor 29 in the memory 65 b (Step S6). In this case, the gauge 9 functions as the notifier, and the input device 10 defines and functions as the input interface.
The steering controllers 22 of the steerings STG for the respective outboard motors OM cooperatively determine whether or not any other outboard motor OM is uncalibrated (Step S7). When the other outboard motor OM is uncalibrated (YES in Step S7), a process sequence from Step S1 is repeated.
That is, an instruction indicating that the steering wheel 6 should be operated to steer the next outboard motor OM, i.e., the second outboard motor from the right side (outboard motor OMp), to the one limit (here, the rightward limit) of the steering range is displayed on the gauge 9 (Step S1). Therefore, the user rotates the steering wheel 6 in the same direction (here, rightward). Then, the steering controller 22 of the steering STGp for the second outboard motor OMp from the side (right side) corresponding to the operation direction actuates the corresponding steering actuator 25 (Step S2). Thus, as shown in FIG. 7C, the outboard motor OMp is steered to the one limit (here, the rightward limit) of the steering range. The output signal value of the steering angle sensor 29 outputted when the steering angle of the outboard motor OMp reaches the one limit (rightward limit) of the steering range is stored as an output signal value corresponding to the one limit (rightward limit) of the steering range of the outboard motor OMp in the memory 65 b (Steps S3, S6). The gauge 9 provides the information (notification) in the same manner as described above when the steering angle of the outboard motor OMp reaches the one limit (rightward limit) of the steering range (Step S4), and the user inputs the command from the input device 10 in the same manner as described above (Step S5).
This process sequence is repeated until the output signal value of the steering angle sensor 29 corresponding to the one limit (e.g., the rightward limit) of the steering range is stored in the memory 65 b for each of the outboard motors OM (Step S7). Thus, the calibration for the one limit (rightward limit) of the steering range ends (NO in Step S7).
Then, an instruction indicating that the steering wheel 6 should be operated to steer the outboard motor OMp located on the other side (here, the left side) to the other limit (here, the leftward limit) of the steering range is displayed on the gauge 9 (Step S8). Following this instruction, the user rotates the steering wheel 6 in the other direction (here, leftward). Then, the steering actuator 25 of the steering STGp for the outboard motor OMp located on a side (here, the left side) corresponding to the operation direction of the steering wheel 6 is actuated such that the outboard motor OMp is steered to the other limit (leftward limit) of the steering range by the corresponding steering STGp (Step S9, see FIG. 7D). When the steering angle of the outboard motor OMp reaches the other limit (leftward limit) of the steering range, the steering of the outboard motor OMp is mechanically restricted and, therefore, the output signal value of the corresponding steering angle sensor 29 does not change. Further, the load of the electric motor M of the outboard motor OMp is increased, thus correspondingly increasing the motor current. Based on this, the corresponding steering controller 22 determines that the steering angle of the outboard motor OMp reaches the other limit (leftward limit) of the steering range (Step S10), and stores the output signal value of the steering angle sensor 29 outputted at this time as an output signal value corresponding to the other limit (leftward limit) of the steering range of the outboard motor OMp in the memory 65 b (Step S13). In the present example embodiment, when the steering angle of the outboard motor OMp reaches the other limit (leftward limit) of the steering range, this information (notification) is displayed on the gauge 9 to be received by the user (Step S11). The user who receives this information (notification) operates the input device 10 to input a command (Step S12). Upon reception of the command, the steering controller 22 stores the output signal value of the steering angle sensor 29 in the memory 65 b (Step S13).
The steering controllers 22 of the steerings STG for the respective outboard motors OM cooperatively determine whether or not any other outboard motor OM is uncalibrated (Step S14). When the other outboard motor OM is uncalibrated (YES in Step S14), a process sequence from Step S8 is repeated.
That is, an instruction indicating that the steering wheel 6 should be operated to steer the next outboard motor OM, i.e., the second outboard motor from the left side (outboard motor OMs), to the other limit (here, the leftward limit) of the steering range is displayed on the gauge 9 (Step S8). Therefore, the user rotates the steering wheel 6 in the same direction (here, leftward). Then, the steering controller 22 of the steering STGs for the second outboard motor OMs from the side (left side) corresponding to the operation direction actuates the steering STGs (Step S9). Thus, as shown in FIG. 7E, the outboard motor OMs is steered to the other limit (leftward limit) of the steering range (Step S10). The output signal value of the steering angle sensor 29 outputted when the steering angle of the outboard motor OMs reaches the other limit (leftward limit) of the steering range is stored as an output signal value corresponding to the other limit (leftward limit) of the steering range of the outboard motor OMs in the memory 65 b (Step S13). The gauge 9 gives the information (notification) in the same manner as described above when the steering angle of the outboard motor OMs reaches the other limit (leftward limit) of the steering range (Step S11), and the user inputs the command from the input device 10 in the same manner as described above (Step S12).
This process sequence is repeated until the output signal value of the steering angle sensor 29 corresponding to the other limit (leftward limit) of the steering range is stored in the memory 65 b for each of the outboard motors OM. Thus, the calibration for the other limit (leftward limit) of the steering range ends.
After the output signal values respectively corresponding to the rightward limit and the leftward limit of the steering range for each of the outboard motors OM are thus stored, the steering controllers 22 perform an automatic steering control operation to cause the steerings STG to steer the corresponding outboard motors OM to a predetermined steering angle (e.g., to the neutral steering angle position) (Step S15, see FIG. 7F). All the outboard motors OM may be simultaneously automatically steered, or the outboard motors OM may be sequentially automatically steered. Where the outboard motors OM are sequentially automatically steered, the automatic steering to the predetermined steering angle position (e.g., the neutral steering angle position) is started with the outboard motor OM steered last for the calibration. That is, at the start of the automatic steering operation, all the outboard motors OM are steered to the other limit (e.g., the leftward limit) of the steering range and, therefore, the outboard motor OM located on a side (e.g., the right side) corresponding to the one limit of the steering range is automatically steered first. This makes it possible to steer each of the outboard motors OM to the predetermined steering angle position (e.g., the neutral steering angle position) while preventing the interference between the adjacent outboard motors OM. Where all the outboard motors OM are simultaneously automatically steered, the outboard motors OM are steered at substantially the same speed to thus prevent the interference therebetween.
The automatic steering operation is performed after the completion of the calibration of the steering angle sensors 29. Therefore, the steering controllers 22 of the steerings STG can each steer the corresponding outboard motor OM to the predetermined steering angle with reference to the output signal of the corresponding steering angle sensor 29. During the automatic steering operation, the steering speed is preferably properly limited so that the outboard motors OM can be automatically slowly steered. The predetermined steering angle is preferably a steering angle within the control steering angle range (e.g., the neutral steering angle). Thus, the steering controllers 22 can be smoothly switched to the feedback control to be performed based on the target steering angle.
During the automatic steering operation, the steering controllers 22 do not respond to the operation speed signal. That is, the outboard motors OM are each automatically steered to the predetermined steering angle irrespective of the operation of the steering wheel 6.
In the present example embodiment, as described above, the output signal values of each of the steering angle sensors 29 respectively corresponding to the one limit and the other limit of the steering range are stored such that the steering controllers 22 can each determine the steering angle from the output signal of the corresponding steering angle sensor 29 based on the stored output signal values. That is, the calibration is performed to correlate the steering angle with the output signal of the steering angle sensor 29. In addition, the outboard motors OM are each automatically steered to the predetermined steering angle (e.g., the neutral steering angle position) after the output signal values of each of the steering angle sensors 29 respectively corresponding to the one limit and the other limit of the steering range are stored. Therefore, the steering controllers 22 can thereafter smoothly start the ordinary steering control operation.
In the present example embodiment, the steering controllers 22 each drive the corresponding steering actuator 25 according to the output signal of the operation speed sensor 12 in the calibration mode such that the steering angles of the steerings STG are each adjusted sequentially to the one limit and the other limit of the steering range. Thus, the user can perform the calibration while checking the operation of the steerings STG. During the automatic steering control operation, the steering actuators 25 are each driven irrespective of the output signal of the operation speed sensor 12 to adjust the steering angle to the predetermined steering angle. That is, after the output signals of each of the steering angle sensors 29 respectively corresponding to the one limit and the other limit of the steering range are stored, the steering controllers 22 do not respond to the operation of the steering wheel 6, but the outboard motors OM are each steered to the predetermined steering angle by the automatic steering control operation. Therefore, the ordinary control operation can be smoothly started after the calibration.
Further, the steering controllers 22 each determine that the steering angle of the corresponding steering STG reaches the one limit of the steering range, and store the output signal value of the corresponding steering angle sensor 29. Then, the steering controllers 22 each determine that the steering angle of the corresponding steering STG reaches the other limit of the steering range, and store the output signal value of the corresponding steering angle sensor 29. Therefore, the output signals of the respective steering angle sensors 29 can be reliably calibrated.
In the present example embodiment, the steering controllers 22 each determine that the steering angle of the corresponding steering STG reaches the one limit and the other limit of the steering range, and display this information (notification) on the gauge 9 to give the information to the user. Then, the user operates the input device 10 to give the command such that the output signal values of the corresponding steering angle sensor 29 are stored. Since the output signal values of the steering angle sensor 29 are stored after being determined by the steering controller 22 and then checked by the user, the output signal of the steering angle sensor 29 can be more reliably calibrated.
The information (notification) output to the user (Step S4, S11) and the command input by the user (Step S5, S12) may be omitted, and the output signal values of the steering angle sensor 29 may be stored (Step S6, S13) based on the determination by the steering controller 22 (Step S3, S10).
In the present example embodiment, the range of the target steering angle (control steering angle range) to be used when the steering controllers 22 control the steering actuators 25 is within the steering range between the one limit and the other limit. This makes it possible to perform the steering control operation while preventing interference between the adjacent outboard motors OM. Thus, the steering angle is adjusted within the control steering angle range by the automatic steering operation at the end of the calibration. Therefore, the ordinary control operation can be thereafter smoothly started.
While example embodiments of the present invention have thus been described, the present invention may be embodied in some other ways as will be described below by way of example.
In the example embodiments described above, the watercraft 1 includes the two outboard motors OM attached to the hull 2 by way of example. The example embodiments described above may be applied to a watercraft including one outboard motor or three or more outboard motors attached to the hull 2.
Propulsion devices other than the outboard motors may be used. Specifically, the example embodiments described above may be applied to a watercraft including inboard motors, inboard/outboard motors, waterjet propulsion devices or other form of propulsion devices.
The prime movers for the propulsion devices are not necessarily required to be the engines, but may be electric motors.
The steering angles are not necessarily required to be the steering angles of the outboard motors, but may be the angles of rudder plates.
The joystick may be used instead of the steering wheel as the steering operator.
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

What is claimed is:

1. A watercraft maneuvering system comprising:

a steering including a steering actuator and operable to change a steering angle to change a course of a watercraft;

a steering angle sensor to detect the steering angle; and

a steering controller configured or programmed to control the steering actuator according to an output signal of the steering angle sensor; wherein

the steering controller includes a calibration mode in which output signal values of the steering angle sensor respectively corresponding to opposite limits of a steering range of the steering are stored, and is configured or programmed to perform an automatic steering control operation to drive the steering actuator to operate the steering to a predetermined steering angle after storing the output signal values of the steering angle sensor respectively corresponding to the opposite limits of the steering range.

2. The watercraft maneuvering system according to claim 1, further comprising:

a steering operator to be operated by a user to steer the watercraft; and

an operation sensor to detect an operation of the steering operator; wherein

the steering controller is configured or programmed to adjust a steering angle of the steering to one of the opposite limits of the steering range and then to the other of the opposite limits by driving the steering actuator according to an output signal of the operation sensor during the calibration mode, and to drive the steering actuator irrespective of the output signal of the operation sensor during the automatic steering control operation.

3. The watercraft maneuvering system according to claim 1, wherein the steering controller is configured or programmed to store one of the output signal values of the steering angle sensor when it is detected that the steering angle of the steering reaches one of the opposite limits of the steering range, and to store another output signal value of the steering angle sensor when it is detected that the steering angle of the steering reaches the other of the opposite limits of the steering range.

4. The watercraft maneuvering system according to claim 3, further comprising:

a notifier to issue a notification when the steering controller has determined that the steering angle of the steering reaches the one of the opposite limits of the steering range during the calibration mode and to issue a notification when the steering controller has determined that the steering angle of the steering reaches the other of the opposite limits of the steering range during the calibration mode; and

an input interface to be operated by a user to input a command in response to each of the notifications; wherein

the steering controller is configured or programmed to store the output signal values of the steering angle sensor when the command is inputted via the input interface in response to each of the notifications during the calibration mode.

5. The watercraft maneuvering system according to claim 1, wherein a range of a target steering angle to be used when the steering controller controls the steering actuator is a steering angle range within the steering range between the one of the opposite limits and the other of the opposite limits.

6. The watercraft maneuvering system according to claim 5, wherein the predetermined steering angle is within the range of the target steering angle.

7. The watercraft maneuvering system according to claim 1, wherein the steering actuator includes a hydraulic actuator including a hydraulic cylinder and an electric pump to supply a hydraulic oil into the hydraulic cylinder.

8. The watercraft maneuvering system according to claim 1, wherein the steering is operable to steer an outboard motor attached to a hull of the watercraft.

9. A watercraft maneuvering system comprising:

a steering including a steering actuator and operable to change a steering angle to change a course of a watercraft; and

a steering controller configured or programmed to control the steering actuator according to an output signal of a steering angle sensor; wherein

the steering controller is configured or programmed to perform an automatic steering control operation to drive the steering actuator to operate the steering to a predetermined steering angle at an end of a calibration mode that calibrates the output signal of the steering angle sensor.

10. A watercraft comprising:

a hull; and

the watercraft maneuvering system according to claim 1 provided on the hull.

11. A watercraft comprising:

a hull; and

the watercraft maneuvering system according to claim 9 provided on the hull.