Patent Description:
Some marine vessels have an automatic steering mode in which a course is automatically controlled without a steering operation. In a marine vessel including a steering wheel having a regulated rotatable angle, there is a concept of a neutral position at a rotation angle position of the steering wheel, wherein a turning angle of a propulsion device corresponds to the rotation angle position of the steering wheel.

In such marine vessel, when an automatic steering mode is cancelled and a steering mode is shifted to a normal steering mode, a current rotation angle position of the steering wheel and a current actual turning angle of the propulsion device may deviate from each other. In a state where the deviation remains, an uncomfortable feeling is sensed when a steering operation is performed.

Therefore, <CIT> discloses a technique of gradually reducing deviation by correcting a change amount of a turning angle of a propulsion device with respect to a steering operation depending on a difference between a rotation direction of a steering wheel and a direction of a current actual turning angle of the propulsion device.

However, with the technique disclosed in <CIT>, the deviation is not reduced while rotation of the steering wheel is stopped. For example, in a case where the steering operation is not performed after a cancellation instruction is given by a button operation or the like in a state in which the deviation occurs, the deviation remains maintained. Therefore, there is room for improvement from a viewpoint of suppressing an uncomfortable feeling in the steering operation while taking into account a case in which the steering operation is not performed when a steering mode is shifted from an automatic steering mode to a normal steering mode.

The present invention provides a steering control device, and a control method, which are capable of suppressing an uncomfortable feeling in a steering operation occurring after cancellation of an automatic steering mode even when the steering operation is not performed in the marine vessel, and a marine vessel comprising the steering control device.

According to a preferred embodiment of the present invention, a steering control device of a marine vessel, wherein the marine vessel includes a hull, a propulsion device that propels the hull, a steering wheel having a regulated rotatable angle, and a turning driver that changes a turning angle of the propulsion device, the steering control device comprising at least one memory that stores a set of instructions, and at least one processor that executes the instructions to: control a steering mode of the marine vessel, the steering mode including a normal steering mode which allows the marine vessel to be steered by a rotation operation of the steering wheel, and an automatic steering mode which allows the marine vessel to be automatically steered without depending on the rotation operation of the steering wheel; acquire a rotation angle position of the steering wheel; acquire an actual turning angle of the propulsion device; determine, based on the acquired rotation angle position, whether or not rotation of the steering wheel is stopped; and when performing the control of the steering mode, during return control to shift the steering mode from the automatic steering mode to the normal steering mode, execute first control to control the turning driver so as to reduce deviation between a turning angle corresponding to the acquired rotation angle position and the acquired actual turning angle in a case where it is determined that the rotation of the steering wheel is stopped.

According to this configuration, a steering wheel has a regulated rotatable angle. A turning driver changes a turning angle of a propulsion device for propelling a hull. A steering mode is controlled, the steering mode including a normal steering mode in which a marine vessel is steered by a rotation operation of the steering wheel and an automatic steering mode in which the marine vessel is automatically steered without depending on the rotation operation of the steering wheel. It is determined whether ore not rotation of the steering wheel is stopped, based on an acquired rotation angle position. In return control executed to shift the steering mode from the automatic steering mode to the normal steering mode, in a case where it is determined that the rotation of the steering wheel is stopped, first control is executed to control the turning driver so that deviation between a turning angle corresponding to the acquired rotation angle position and an acquired actual turning angle is reduced.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<FIG> is a top view of a marine vessel <NUM> to which a steering control device according to a preferred embodiment of the present invention is applied. A marine vessel <NUM> includes a hull <NUM> and a plurality of (for example, a pair of) outboard motors <NUM> (15A and 15B) each serving as a propulsion device that propels the hull <NUM>. A central unit <NUM>, a steering wheel <NUM>, and a remote control unit <NUM> are provided in the vicinity of a steering seat of the hull <NUM>.

In the following description, "forward", "rearward", "left", "right", "upward", and "downward" directions respectively indicate forward, rearward, left, right, upward, and downward directions of the hull <NUM>. For example, as illustrated in <FIG>, a center line C1 extending in the forward-and-rearward direction of the hull <NUM> passes through the center of gravity G of the marine vessel <NUM>. The forward-and-rearward direction is a direction parallel to the center line C1. The front side ("forward") is a direction oriented upwards along the center line C1, in the drawing of <FIG>. The rear side ("rearward") is a direction oriented downwards along the center line C1, in the drawing of <FIG>. The "left"-and- "right" direction is defined by left-and-right of a case in which the hull <NUM> is viewed from the rear side. The "upward"- and-"downward" direction is a direction perpendicular to the forward-and-rearward direction and to the left-and-right direction.

The two outboard motors <NUM> are mounted side by side at the stern of the hull <NUM>. When the two outboard motors <NUM> are distinguished from each other, the one disposed on the port side is referred to as an "outboard motor 15A", and the other one disposed on the starboard side is referred to as an "outboard motor 15B". Each of the outboard motors 15A and 15B is attached to the hull <NUM> via an attachment unit <NUM> (14A and 14B). Each of the outboard motors 15A and 15B includes an engine <NUM> (16A, 16B) serving as a drive source.

Each outboard motor <NUM> obtains propulsive force by a propeller (not illustrated) rotated by drive force of the engine <NUM> corresponding thereto. The attachment units <NUM>, the engines <NUM>, and the like are also referred to as the attachment units 14A and 14B and the engines 16A and 16B, respectively, corresponding to the outboard motors 15A and 15B when distinguished from each other.

The remote control unit <NUM> includes two throttle levers, and is operated to adjust outputs of the engines 16A and 16B and to perform switching between a forward movement and a rearward movement of the marine vessel. Each throttle lever can be operated in the forward direction and the rearward direction from the zero operation position.

Since the configurations of the outboard motors 15A and 15B are common to each other, one outboard motor <NUM> will be described. The outboard motor <NUM> includes the attachment unit <NUM> adopted to attach an outboard motor main body to the hull <NUM>, and a steering shaft (not illustrated). The steering shaft is provided in the outboard motor main body and is supported by the attachment unit <NUM>. The outboard motor main body is configured to be steerable to the left and right about the steering shaft. The outboard motor main body is attached to the rear portion of the hull <NUM> via the steering shaft and the attachment unit <NUM>. When the steering wheel <NUM> is operated, the outboard motor main body turns left and right (R1 direction) about a pivot center C2. As a result, the marine vessel <NUM> is steered. Further, the outboard motor main body is rotatable about a tilt shaft (not illustrated) via the attachment unit <NUM>.

<FIG> is a block diagram of a steering system in the marine vessel <NUM>. The steering system includes the steering control device of the present preferred embodiment.

The steering system includes a controller <NUM>, the engines 16A and 16B, a rotation angle sensor <NUM>, turning angle sensors <NUM>, various sensors <NUM>, various operators <NUM>, a load generation unit <NUM>, a display unit <NUM>, and a turning actuator <NUM>.

The controller <NUM> includes a CPU <NUM>, a ROM <NUM>, a RAM <NUM>, and a timer (not illustrated). The ROM <NUM> stores a control program. The CPU <NUM> implements various types of control processing by loading the control program stored in the ROM <NUM> in the RAM <NUM> and executing the control program. The RAM <NUM> provides a work area used when the CPU <NUM> executes the control program.

The turning actuator <NUM> is provided correspondingly to each of the outboard motors 15A and 15B. The turning actuator <NUM> rotates the corresponding outboard motor <NUM> with respect to the hull <NUM> about the pivot center C2 (in <FIG>). Therefore, the turning actuator <NUM> serving as a turning driver changes the turning angle of the corresponding outboard motor <NUM>. A direction in which propulsive force acts can be changed with respect to the center line C1 of the hull <NUM>, by each of the outboard motors 15A and 15B being rotated about the pivot center C2.

The turning angle sensor <NUM> is provided correspondingly to each of the outboard motors 15A and 15B and detects an actual turning angle of the corresponding outboard motor 15A and an actual turning angle of the corresponding outboard motor 15B. It is noted that the controller <NUM> may acquire the actual turning angle from a steering instruction value output to the turning actuator <NUM>.

The rotation angle sensor <NUM> detects a rotation angle position of the steering wheel <NUM>. The various sensors <NUM> include a throttle opening sensor, a throttle sensor, an engine rotation speed sensor, a hull speed sensor, a hull acceleration sensor, an azimuth sensor, a distance sensor, a posture sensor, a position sensor, a GPS sensor, and the like. Detection signals from the rotation angle sensor <NUM> and the various sensors <NUM> are supplied to the controller <NUM>. The throttle opening sensor and the engine rotation speed sensor are provided in the corresponding outboard motor <NUM>. The hull speed sensor, the hull acceleration sensor, the azimuth sensor, the distance sensor, the posture sensor, and the position sensor are, for example, included in the central unit <NUM> or disposed in the vicinity of the central unit <NUM>.

The engine rotation speed sensor detects a rotation speed, which is revolution per unit period of time, of the corresponding engine <NUM>. The throttle opening sensor detects an opening of a throttle valve (not illustrated). The hull speed sensor detects a navigation speed (vessel speed) of the marine vessel <NUM> (hull <NUM>). The hull acceleration sensor detects acceleration of the marine vessel <NUM> (hull <NUM>). The posture sensor includes, for example, a gyro sensor, a magnetic azimuth sensor, and the like. It is noted that the vessel speed and the hull acceleration may be acquired from a GPS signal received by the GPS sensor.

The various operators <NUM> include an operator for performing an operation related to steering, a setting operator for performing various settings, and an input operator for inputting various instructions. The various operators <NUM> are included in the central unit <NUM> or disposed in the vicinity of the central unit <NUM>. Some of the various operators <NUM> may be disposed on the steering wheel <NUM>. The various operators <NUM> are operated by a vessel operator, and operation signals thereof are supplied to the controller <NUM>.

It is noted that the controller <NUM> may establish predetermined communication with the rotation angle sensor <NUM>, the turning angle sensor <NUM>, the various sensors <NUM>, the various operators <NUM>, and the like to exchange information. The display unit <NUM> displays various types of information.

The load generation unit <NUM> is, for example, an electromagnetic brake that generates a load in response to a rotation operation of the steering wheel <NUM>. For example, when the electromagnetic brake is in the non-energized state, a rotational load is very small or zero compared to rotational torque of the steering wheel <NUM>, whereas when the electromagnetic brake is in the energized state, the rotational load is large, and a large rotational load acts on the rotation operation of the steering wheel <NUM> performing. It is noted that the load generation unit <NUM> may have any configuration as long as the configuration generates a load acting on the rotation operation of the steering wheel <NUM>, and another configuration other than the electromagnetic brake may be adopted for the load generation unit <NUM>.

It is noted that the steering system may further include a power trim and tilt mechanism (PTT mechanism) that rotates the outboard motor <NUM> about a tilt axis, a trim tab actuator that drives a tab body, and/or the like.

It is noted that the controller <NUM> may control each engine <NUM> via an outboard motor ECU (not illustrated) provided in each outboard motor <NUM>. It is noted that it is not essential to include all the sensors described above.

<FIG> is a diagram illustrating the steering wheel <NUM> substantially viewed from the front. The steering wheel <NUM> includes a central portion <NUM>, an annular wheel portion <NUM>, and three spoke portions (a first spoke portion <NUM>, a second spoke portion <NUM>, and a third spoke portion <NUM>). The steering wheel <NUM> is supported by the hull <NUM> so as to be rotatable about a rotation fulcrum C0 which is an axial line of a steering shaft <NUM>.

As viewed in the axial direction of the rotation fulcrum C0, a virtual straight line passing through the center position of the third spoke portion <NUM> in the width direction and the rotation fulcrum C0 is referred to as a "virtual straight line L0". A rotatable angle of the steering wheel <NUM> is finite, and a concept of a "neutral position" exists in a rotation range. In <FIG>, the steering wheel <NUM> is located at the neutral position. When the steering wheel <NUM> is located at the neutral position, a point P0 on the virtual straight line L0 in the wheel portion <NUM> is located immediately above the rotation fulcrum C0 when viewed from the front. The neutral position is a rotational position of the steering wheel <NUM> when causing the hull <NUM> to moved forwards (to go straight).

The steering wheel <NUM> is rotatable by an angle θ11 to the left and an angle θ12 to the right, from the neutral position thereof. The angles θ11 and θ12 are both <NUM>°. That is, with the neutral position as a reference, a rotatable angle θ10 of the steering wheel <NUM> is regulated by a first angle position θL, which is a rotation end position in the left rotation direction, and is regulated by a second angle position θR, which is a rotation end position in the right rotation direction. As an example, on the assumption that the rotation angle position of the steering wheel <NUM> located at the neutral position is zero, the first angle position θL is -<NUM>°, and the second angle position θR is +<NUM>°.

The significances of a "shift prohibition range" and a "shiftable range" will be described later (in <FIG> and subsequent drawings). A range from the first angle position θL to an angle position rotated from the first angle position θL by a first predetermined angle amount in the right rotation direction is defined as a shift prohibition range θ13. A range from the second angle position θR to an angle position rotated from the second angle position θR by a second predetermined angle amount in the left rotation direction is defined as a shift prohibition range θ15. As an example, it is assumed that the first predetermined angle amount and the second predetermined angle amount are both <NUM>°. Therefore, both the shift prohibition ranges θ13 and θ15 are in a range of <NUM>° in the neutral direction from the end position of the rotatable angle θ10. The range of an angle θ14 and an angle θ16 in <FIG> are the shiftable range. The angle θ14 and the angle θ16 are both <NUM>°, and thus the shiftable range is <NUM>°.

It is noted that the values of θ10 to θ16 are not limited to the exemplified values. In addition, the value of θ11 and the value of θ12, the value of θ13 and the value of θ15, and the value of θ14 and the value of θ16, may be different from each other.

The steering wheel <NUM> includes a plurality of switches. For example, a changeover switch <NUM>, a left switch <NUM>, and a right switch <NUM> are disposed on the surface of the steering wheel <NUM>. These switches are included in the various operators <NUM> (in <FIG>).

The steering mode will be described. The steering mode is roughly classified into a "normal steering mode" and an "automatic steering mode". Hereinafter, the automatic steering mode is referred to as an "AP mode". The steering mode is switched every time the changeover switch <NUM> is pressed.

The normal steering mode is a mode in which steering is performed according to the rotation operation of the steering wheel <NUM> or the like. For example, in the normal steering mode, the controller <NUM> controls the rotation speeds and/or the rotation directions of the engines <NUM> and 16R and the turning angle by the turning actuator <NUM>, in accordance with the operation amount and/or the operation direction of the throttle lever in the remote control unit <NUM> and the rotation angle position of the steering wheel <NUM>.

The AP mode is a mode in which steering is automatically performed without depending on the rotation operation of the steering wheel <NUM>. For example, the AP mode includes a plurality of types of modes such as lateral movement, oblique movement, and in-situ turning, in addition to "course holding travel" for holding a certain course and "azimuth holding travel" for holding a certain azimuth. The type of the AP mode is designated according to an operation of a setting operator and/or an input operator in the various operators <NUM>. The controller <NUM> implements a designated type of the AP mode by controlling turning angles, shift positions, engine rotation speeds, and the like of the two outboard motors <NUM>.

It is noted that a predetermined operation may be executed when a predetermined operator of the various operators <NUM> is operated in the AP mode. For example, the controller <NUM> may control the hull <NUM> to temporarily move laterally to the left or right, when the left switch <NUM> or the right switch <NUM> is operated.

<FIG> is a timing chart illustrating the transition of the steering mode. A horizontal axis represents a time. A vertical axis represents a rotation angle position of the steering wheel <NUM> (hereinafter, also referred to as a "steering angle") and actual turning angles of the outboard motors 15A and 15B. It is noted that, here, since it is assumed that the vessel goes straight in the instructed direction, the actual turning angles (solid lines) of the outboard motors 15A and 15B are common to each other. The steering angle is indicated by a dotted line.

The controller <NUM> switches the steering mode to the AP mode in response to acquisition of a start instruction of the AP mode by the operation on the changeover switch <NUM> or the like in the normal steering mode. It is noted that the "normal steering mode" is indicated as a "normal mode" in the drawing. In the AP mode, the controller <NUM> starts normal steering mode return processing (return control) in response to a cancellation instruction of the AP mode. There are one or more manners of canceling the AP mode, and a typical manner thereof is to change the steering angle beyond a threshold angle TH (for example, ±<NUM>°) so as to cancel the AP mode. This is because when the steering angle is changed beyond the threshold angle TH, it is considered that the vessel operator has an intention of resuming manual steering.

Here, the start of the AP mode in the normal steering mode will be described. The controller <NUM> switches the steering mode to the AP mode in a case where the steering angle is changed so as to fall within the shiftable range (the angle θ14 or the angle θ16) and does not switch the steering mode to the AP mode in a case where the steering angle is changed so as to fall within the shift prohibition ranges θ13 or θ15.

It is assumed that even when the steering angle is within the shift prohibition ranges θ13 or θ15, the steering mode was switched to the AP mode. In this case, there is a possibility that the steering angle cannot be changed beyond the threshold angle TH even if the vessel operator intends to resume manual steering in a state in which the steering angle remains the same when the steering mode is switched to the AP mode. For example, when the steering angle is in the vicinity of the left rotation end position, there is little room to further rotate the steering wheel <NUM> in the left direction. In order to avoid such a case, the shift prohibition ranges θ13 and θ15 are provided.

Referring to <FIG>, at a time point T0, the normal steering mode is started by starting a system. In response to the start instruction of the AP mode at a time point T1, the start of the AP mode is attempted. In a case where a shift condition to the AP mode is satisfied, such as a case in which the steering angle falls within the shiftable range, the mode is switched to the AP mode. It is noted that details of the processing related to the start of the AP mode including determination of the shift condition to the AP mode will be mainly described later with reference to <FIG>.

Processing in the AP mode will be mainly described later with reference to <FIG>. In the AP mode, when the hull <NUM> comes straight ahead in the instructed direction, the actual turning angle converges to <NUM>. In the AP mode, a notification is given to return the steering wheel <NUM> to the neutral position. When the vessel operator returns the steering wheel <NUM> to the neutral position in response to the notification, the steering angle ideally coincides with the actual turning angle (a time point T2).

At a time point T3, cancellation of the AP mode is instructed. At this time point, the steering angle may not coincide with the actual turning angle, that is, there may be deviation between the steering angle and the actual turning angle, for some reason. The controller <NUM> determines that there is deviation in a case where there is a predetermined difference or more between the steering angle and the actual turning angle. In a case where there is the deviation, the controller <NUM> reduces the deviation (time points T3 to T6) and then starts the normal steering mode. The control processing during this period (between the time points T3 to T6) is "return processing" to the normal steering mode (described later mainly with reference to <FIG>).

In the return processing, when the steering wheel <NUM> is in the rotationally stopped state (that is, in a case where the steering angle has not been changed beyond the predetermined angle from the time of the previous steering angle acquisition), the controller <NUM> executes "control during stop (first control)".

The outline will be described. In the control during stop, the controller <NUM> controls the turning actuator <NUM> so that the deviation between "the turning angle corresponding to the steering angle" and the actual turning angle becomes small. Here, the "turning angle corresponding to the steering angle" is a turning angle on the instruction determined by the current rotation angle position of the steering wheel <NUM> when it is assumed that the normal steering mode is set. The deviation between the steering angle and the actual turning angle at the start of the normal steering mode is reduced, and therefore it is possible to suppress an uncomfortable feeling in the steering operation. For example, the control during stop is applied in the time period between the time points T5 and T6, and the deviation is eliminated at a time point T6. As a result, the uncomfortable feeling in the steering operation at the start of the normal steering mode is suppressed without necessity of the rotation operation for reducing the deviation in the AP mode.

On the other hand, in the return processing, when the steering wheel <NUM> is rotating (that is, in a case where the steering angle has changed beyond the predetermined angle from the time of the previous steering angle acquisition), the controller <NUM> executes "control during rotation (second control)".

In the control during rotation, a change amount of the actual turning angle corresponding to a rotation amount of the steering wheel <NUM> is corrected using a relationship between the rotation direction of the steering wheel <NUM> and the actual turning angle. For example, in a case where "the steering wheel <NUM> is rotating in a direction in which the turning angle corresponding to the steering angle approaches the actual turning angle", the controller <NUM> changes the actual turning angle by "a value obtained by correcting the turning angle corresponding to the rotation amount of the steering wheel <NUM> to a smaller value". This control is applied in the time period between the time point T4 and the time point T5, and a change in the actual turning angle is smaller than a change in the turning angle corresponding to the steering angle. The direction of change between the two is common.

On the other hand, in the control during rotation, in a case where "the steering wheel <NUM> is rotating in a direction in which the turning angle corresponding to the steering angle is away from the actual turning angle", the controller <NUM> changes the actual turning angle by "a value obtained by correcting the turning angle corresponding to the rotation amount of the steering wheel <NUM> to a larger value". This control is applied in the time period between the time point T3 and the time point T4, and a change in the actual turning angle is larger than a change in the turning angle corresponding to the steering angle. The direction of change between the two is common.

As described above, with the control during rotation, even if the rotation operation on the steering wheel <NUM> is performed in the AP mode, deviation decreases, which makes it possible to suppress an uncomfortable feeling in the steering operation at the start of the normal steering mode.

<FIG> is a diagram illustrating a first functional block for implementing control in the normal steering mode. <FIG> is a diagram illustrating a second functional block for implementing return processing of returning the steering mode from the AP mode to the normal steering mode. It is noted that it is not essential to provide both the functional blocks illustrated in <FIG>, and the first functional block and/or the second functional block may be provided depending on control to be implemented.

The first functional block (in <FIG>) includes, as functional units, a first acquisition unit <NUM>, a second acquisition unit <NUM>, and a controller <NUM>. The second functional block (in <FIG>) includes, as functional units, a first acquisition unit <NUM>, a second acquisition unit <NUM>, a determination unit <NUM>, and a controller <NUM>. The functional units of the first functional block and the second functional block are implemented mainly by cooperation among the components <NUM> to <NUM>, the engine <NUM>, and the controller <NUM>.

First, the first functional block (in <FIG>) will be described. The function of the first acquisition unit <NUM> is implemented mainly by the rotation angle sensor <NUM> and the controller <NUM>. The first acquisition unit <NUM> acquires the rotation angle position of the steering wheel <NUM> (steering angle) from the rotation angle sensor <NUM>.

The function of the second acquisition unit <NUM> is implemented mainly by the changeover switch <NUM> and the controller <NUM>. The second acquisition unit <NUM> acquires the start instruction of the AP mode from an operation signal of the changeover switch <NUM>.

The function of the controller <NUM> is mainly implemented by the controller <NUM>. The controller <NUM> performs control to shift the steering mode to the AP mode in response to acquisition of the start instruction of the AP mode in the normal steering mode. In addition, the controller <NUM> performs control to shift the steering mode to the normal steering mode in response to a change in the steering angle beyond the threshold angle TH in the AP mode. Further, the controller <NUM> does not switch the steering mode to the AP mode when the steering angle falls within the shift prohibition range θ13 or θ15 in a state in which the steering mode is in the normal steering mode. That is, in a case where a difference between the acquired steering angle and the first angle position θL is smaller than a first predetermined angle amount or in a case where a difference between the acquired steering angle and the second angle position θR is smaller than a second predetermined angle amount, the controller <NUM> does not switch the steering mode to the AP mode even if the start instruction of the AP mode is issued.

Next, the second functional block (in <FIG>) will be described. The function of the first acquisition unit <NUM> is similar to the function of the first acquisition unit <NUM>. The function of the second acquisition unit <NUM> is similar to the function of the second acquisition unit <NUM>.

The function of the determination unit <NUM> is implemented mainly by the controller <NUM>. The determination unit <NUM> determines whether the rotation of the steering wheel <NUM> is stopped, based on the rotation angle position of the steering wheel <NUM> (steering angle) acquired by the first acquisition unit <NUM>.

The function of the controller <NUM> is implemented mainly by the controller <NUM>. In the returning processing described above, the controller <NUM> executes the above-described control during stop or the above-described control during rotation, based on determination of whether or not rotation of the steering wheel <NUM> is stopped and a relationship between the rotation direction of the steering wheel <NUM> and the actual turning angle.

<FIG> is a flowchart of mode switching processing. The mode switching processing is implemented by the CPU <NUM> loading the program stored in the ROM <NUM> in the RAM <NUM> and executing the program. This processing is started, for example, when the steering system is started.

<FIG> is a flowchart of processing in the AP mode to be executed in step S107 of <FIG>. <FIG> is a flowchart of the normal steering mode return processing to be executed in step S207 of <FIG>. The mode switching processing will be described with reference to <FIG> as well.

Immediately after the mode switching processing in <FIG> is started, initialization is executed, and the steering mode is set to the normal steering mode (the time point T0 in <FIG>). In addition, communication with sensors and operators is established to enable acquisition of information and output of an instruction.

In step S101, the controller <NUM> executes "other processing". In the "other processing", the controller <NUM> executes processing such as starting clocking by a timer, establishing communication when communication is interrupted, and the like. In addition, when a forced termination instruction is input, the controller <NUM> may terminate the mode switching processing in <FIG>.

In step S102, the controller <NUM> determines whether or not a current state is "a state in which communication is restored after interruption of communication continues for less than a first predetermined period of time (for example, one second)". For example, in the following case, the controller <NUM> determines "YES" in step S102: a case in which a current state enters a state in which "a detection result of (steering angle) the rotation angle position of the steering wheel <NUM> by the rotation angle sensor <NUM> cannot be acquired" or enters a state in which "the actual turning angle cannot be acquired from the turning angle sensor <NUM>", and then the state returns to a state in which these pieces of information (the detection result and the actual turning angle, respectively) can be acquired before the first predetermined period of time (for example, one second) has elapsed. In such a situation in which YES is determined in step S102, there is a possibility that deviation occurs between the steering angle and the actual turning angle. Therefore, in order to execute the return processing, the controller <NUM> advances the processing to step S207 in <FIG> (normal steering mode return processing in <FIG>) (the time point T3). It is noted that, when the state in which the actual turning angle and/or the steering angle cannot be acquired continues for the first predetermined period of time or longer due to continuation of interruption of communication or the like, the controller <NUM> may issue a notification of an error and stop the vessel.

On the other hand, in a case where "the state in which communication is restored after interruption of communication continues for less than the first predetermined period of time" is not satisfied, the controller <NUM> advances the processing to step S103. In step S103, the controller <NUM> determines whether or not the start instruction of the AP mode has been acquired by receiving an operation signal from the changeover switch <NUM> or the like. In a case where the start instruction of the AP mode has not been acquired, the controller <NUM> returns the processing to step S101. In a case where the start instruction of the AP mode has been acquired, the controller <NUM> advances the processing to step S104.

In step S104, the controller <NUM> determines the shift prohibition ranges θ13 and θ15. As an example, the controller <NUM> determines the first predetermined angle amount and the second predetermined angle amount, based on at least one of the vessel speed detected by the hull speed sensor among the various sensors <NUM> and the engine rotation speed detected by the engine rotation speed sensor among the various sensors <NUM>. As a result, the shift prohibition range θ13, which is a range between the first angle position θL and a portion reached by rotating the first angle position θL in the right rotation direction by the first predetermined angle amount, is determined. In addition, the shift prohibition range θ15, which is a range between the second angle position θR and a portion reached by rotating the second angle position θR in the left rotation direction by the second predetermined angle amount, is determined. For example, the shift prohibition ranges θ13 and θ15 are wider as the vessel speed is higher, and the shift prohibition ranges θ13 and θ15 are wider as the engine rotation speed is higher.

It is noted that, in the present preferred embodiment, the shift prohibition ranges θ13 and θ15 are dynamically changed; however, the shift prohibition ranges θ13 and θ15 may be fixed values. In this case, the processing of step S104 may be omitted.

In step S105, the controller <NUM> determines whether or not the shift condition to the AP mode is satisfied. For example, the shift condition to the AP mode means that the current steering angle does not belong to the shift prohibition range θ13 or θ15 and belongs to the shiftable range. That is, in a case where a difference between the acquired steering angle and the first angle position θL is greater than or equal to the first predetermined angle amount, and a difference between the acquired steering angle and the second angle position θR is greater than or equal to the second predetermined angle amount, the steering angle belongs to the shiftable range and, as such, the shift condition to the AP mode is satisfied. It is noted that, in addition thereto, the shift condition may be that a yaw rate acquired by detection signals from the posture sensor of the various sensors <NUM> falls within a predetermined value.

In a case where the shift condition to the AP mode is not satisfied, the controller <NUM> advances the processing to step S108 and executes notification processing. This notification processing may be executed, for example, by at least one of display of a message using the display unit <NUM>, lighting indication using an LED not illustrated, and a voice message using a sound generator not illustrated (which can be similarly applied to notification processing to be described below). In this notification processing, for example, the controller <NUM> issues a notification that the steering mode cannot be shifted to the AP mode. Further, the controller <NUM> may issue a notification to return the steering wheel <NUM> to the neutral position. When the vessel operator rotationally operates the steering wheel <NUM> toward the neutral position in response to a notification issued to prompt to return the steering wheel <NUM> to the neutral position, there is a possibility that the steering angle deviates from the shift prohibition range θ13, θ15 and belongs to the shiftable range.

In step S109, the controller <NUM> determines whether or not a predetermined period of time (second predetermined period of time) has elapsed from the start of the notification processing in the first step S108. In a case where the second predetermined period of time has not elapsed, the controller <NUM> returns the processing to step S105, and in a case where the second predetermined period of time has elapsed, the controller <NUM> advances the processing to step S110.

In step S110, since the shift condition to the AP mode is not satisfied even after the second predetermined period of time has elapsed, the controller <NUM> executes notification processing and then returns the processing to step S101. In the notification processing in step S110, the controller <NUM> issues a notification that the steering mode could not be shifted to the AP mode. Further, the controller <NUM> may issue a notification to return the steering wheel <NUM> to the neutral position. When the vessel operator rotationally operates the steering wheel <NUM> toward the neutral position in response to a notification issued to prompt to return the steering wheel <NUM> to the neutral position, there is a possibility that the steering angle deviates from the shift prohibition range θ13, θ15 and belongs to the shiftable range. In this case, there is a possibility that the steering mode can be shifted to the AP mode when the vessel operator instructs the start of the AP mode again in the processing after the resumed (second and subsequent) step S101.

In a case where the controller <NUM> determines, in step S105, that the shift condition to the AP mode is satisfied, the processing proceeds to step S106. In a case where the shift condition to the AP mode is satisfied during the loop of steps S105, S108, and S109, the controller <NUM> advances the processing from step S105 to step S106. For example, when the vessel operator rotationally operates the steering wheel <NUM> toward the neutral position and the steering angle belongs to the shiftable range, the processing can proceed to step S106. In this case, the vessel operator can shift the steering mode to the AP mode without instructing the start of the AP mode again. It is noted that it is not essential to provide steps S108 and S109.

In step S106, the controller <NUM> starts the AP mode (the time point T1). In step S107, the controller <NUM> executes the processing in the AP mode (in <FIG>) (the time point T1 to the time point T3). After step S107, the controller <NUM> returns the processing to step S101.

In step S201 of <FIG>, the controller <NUM> starts notification processing. In this notification processing, for example, the controller <NUM> issues a notification that the steering mode has shifted to the AP mode. Further, the controller <NUM> may issue a notification to return the steering wheel <NUM> to the neutral position.

In step S202, the controller <NUM> executes "other processing". In the "other processing" here, the controller <NUM> acquires various detection values such as a steering angle, and starts clocking by a timer, and the like. The controller <NUM> sets/updates the steering angle acquired this time as a reference position. In the "other processing", the controller <NUM> further executes processing such as establishing communication in a case where communication is interrupted. It is noted that, when the communication interruption state continues for the first predetermined period of time or longer, the controller <NUM> may issue a notification of an error and stop the vessel. In addition, when a forced termination instruction is input, the controller <NUM> may terminate the mode switching processing (in <FIG>).

In step S203, the controller <NUM> determines whether or not an AP mode cancellation condition is satisfied. As described above, one of the AP mode cancellation conditions includes that the steering angle has been changed beyond the threshold angle TH. In addition, one of the AP mode cancellation conditions includes that the changeover switch <NUM> is operated (pressed again in the AP mode). Therefore, the AP mode cancellation condition is satisfied when the steering angle is changed from the reference position set in step S202 beyond the threshold angle TH or when the changeover switch <NUM> is pressed. This is because, in such a case, it is considered that an intention of performing manual steering is presented. In addition, operations of other operators, such as the left switch <NUM> and the right switch <NUM>, may also be included in one of the AP mode cancellation conditions.

In a case where the AP mode cancellation condition is satisfied, the controller <NUM> advances the processing to step S207 (the time point T3), executes normal steering mode return processing (in <FIG>), and then terminates the processing in the AP mode (in <FIG>). On the other hand, in a case where the AP mode cancellation condition is not satisfied, the controller <NUM> advances the processing to step S204.

As described above, when the vessel operator returns the steering wheel <NUM> to the neutral position before the AP mode cancellation condition is satisfied, it is expected that deviation between the steering angle and the actual turning angle at the time when the steering mode returns to the normal steering mode becomes small. As a result, it is possible to prevent a sudden change in the turning angle at the time of returning to the normal steering mode and to suppress an uncomfortable feeling in the steering operation. Furthermore, since when the steering wheel <NUM> is located at the neutral position, the current position of the operators on the steering wheel <NUM> can be easily properly understood and, as such, the switches and the like can be easily operated in the AP mode. For example, since the left switch <NUM> and the right switch <NUM> are respectively located on the left and right positions which are positions at which the left switch <NUM> and the right switch <NUM> should be originally located, an operation is easily performed for the vessel operator.

In step S204, the controller <NUM> determines whether or not the steering angle acquired last belongs to a neutral range (a predetermined range). Here, the neutral range is a range of a predetermined angle from the neutral position (for example, ±<NUM>°) and is determined and acquired in advance. In a case where the steering angle acquired last belongs to the neutral range, the controller <NUM> advances the processing to step S205, and stops the notification processing which started in step S201 and has been continued. This is because when the steering angle is located in the neutral range, the deviation between the steering angle and the actual turning angle at the time of returning to the normal steering mode is considered to be small.

In step S206, the controller <NUM> turns on a bidirectional load. Specifically, the controller <NUM> drives the load generation unit <NUM> to generate a load (friction) on a rotation operation of the steering wheel <NUM>, regardless of a rotation direction. As a result, since a load acts on the steering wheel <NUM> performing the rotation operation thereof when the steering wheel <NUM> within the neutral range is rotated in either the right or left direction, there is an effect of urging the vessel operator tactilely to keep the steering wheel <NUM> in the neutral range. It is noted that, when the processing exits from the AP mode processing, the bidirectional load is cancelled. After step S206, the controller <NUM> returns the processing to step S202.

It is noted that, in step S206, the load may be controlled to be larger than a load to be applied when the steering angle does not belong to the neutral range. Therefore, the load to be applied when the steering angle does not belong to the neutral range may be greater than zero.

In step S204, in a case where it is determined that the steering angle acquired last does not belong to the neutral range, the controller <NUM> advances the processing to step S208. In step S208, the controller <NUM> determines whether or not there is a rotation operation of the steering wheel <NUM> (steering rotation operation) in a direction away from the neutral range. This determination is performed by comparing a value of the steering angle acquired last time with a value of the steering angle acquired this time. Then, in a case where the controller <NUM> determines that the steering rotation operation is performed in the direction away from the neutral range, the controller <NUM> advances the processing to step S209. In a case where the controller <NUM> determines that the steering rotation operation in the direction away from the neutral range has not been performed, the controller <NUM> advances the processing to step S210.

In step S209, the controller <NUM> turns on the load. Specifically, the controller <NUM> drives the load generation unit <NUM> to generate the load acting on the steering wheel <NUM> performing the rotation operation thereof in the direction away from the neutral range. On the other hand, in step S210, the controller <NUM> turns off the load. Therefore, the controller <NUM> does not generate the load acting on the steering wheel <NUM> performing the rotation operation thereof. Such processing of so-called "unidirectional braking" has an effect of tactilely urging the vessel operator to keep the steering wheel <NUM> in the neutral range.

It is noted that, in step S209, when the steering rotation operation is performed in the direction away from the neutral range, the load may be controlled to be larger than that to be applied when the steering rotation operation is performed in a direction approaching the neutral range. Therefore, the load to be applied when the steering rotation operation is performed in the direction approaching the neutral range may be greater than zero.

After step S209 or S210, the controller <NUM> returns the processing to step S202.

In step S301 of <FIG>, the controller <NUM> executes "other processing". In this "other processing" here, the controller <NUM> acquires various detection values such as the actual turning angle, and starts clocking by a timer, and the like. In addition, the controller <NUM> waits for a certain period of time in order to secure a steering angle acquisition period used to determine whether the steering wheel <NUM> is in the rotationally stopped state (step S304 described later). In addition, the controller <NUM> further executes processing such as establishing communication in a case where communication is interrupted. It is noted that, when the communication interruption state continues for the first predetermined period of time or longer, the controller <NUM> may issue a notification of an error and stop the vessel. In addition, when a forced termination instruction is input, the controller <NUM> may terminate the mode switching processing (in <FIG>).

In step S302, the controller <NUM> acquires the steering angle. In step S303, the controller <NUM> determines whether or not there is deviation (a predetermined difference or more) between the acquired steering angle and the actual turning angle. Then, in a case where there is the deviation, the controller <NUM> advances the processing to step S304.

In step S304, the controller <NUM> determines whether or not the steering wheel <NUM> is in the rotationally stopped state. This determination is performed by comparing a previous value of the steering angle with a current value of the steering angle, wherein it is determined that the rotation is stopped (in the rotationally stopped state) in a case where a difference between the previous value of the steering angle and the current value of the steering angle is less than a predetermined angle difference. Then, the controller <NUM> advances the processing to step S305 in a case where the steering wheel <NUM> is in the rotationally stopped state, and advances the processing to step S306 in a case where the steering wheel <NUM> is not stopped (is not in the rotationally stopped state).

In step S305, as described above, the controller <NUM> executes the control during stop (first control) (the time points T5 to T6). Two methods described below are conceivable for the control during stop, and any one of the two methods is adopted. It is noted that which method to be adopted may be determined by the vessel operator.

First, in the first method of the control during stop, the controller <NUM> determines, based on an amount of deviation, a change amount Δ per unit period of time of the turning angle of the outboard motor <NUM>, wherein the change amount Δ is used when the turning actuator <NUM> is controlled so as to reduce deviation. For example, the larger the amount of deviation between the steering angle and the actual turning angle, the faster the controller <NUM> changes the turning angle of the outboard motor <NUM>. At that time, the controller <NUM> may determine the change amount Δ so that deviation is eliminated within a target period of time (for example, within <NUM> seconds). By determining the change amount Δ in this manner, it is possible to eliminate an uncomfortable feeling in the steering operation at an appropriate speed and within the target period of time.

In a second method of the control during stop, the controller <NUM> determines the change amount Δ based on at least one of the vessel speed and the engine rotation speed. For example, the controller <NUM> sets the change amount Δ to a smaller value as the vessel speed or the like is faster. As a result, it is possible to prevent a sudden change in the turning angle at the time of returning to the normal steering mode without requiring a rotation operation, which makes it possible to smoothly perform the shift to the normal steering mode.

It is noted that the controller <NUM> may determine the change amount Δ based on at least one of the amount of deviation, the vessel speed, and the engine rotation speed, without determining the target period of time.

In step S306, as described above, the controller <NUM> executes the control during rotation (second control) (the time points T3 to T5). When the steering wheel <NUM> rotates in a direction in which the turning angle corresponding to the steering angle moves away from the actual turning angle, the controller <NUM> changes the actual turning angle by a value obtained by correcting the turning angle corresponding to the rotation amount of the steering wheel <NUM> to a larger value. When the steering wheel <NUM> rotates in a direction in which the turning angle corresponding to the steering angle approaches the actual turning angle, the controller <NUM> changes the actual turning angle by a value obtained by correcting the turning angle corresponding to the rotation amount of the steering wheel <NUM> to a smaller value.

It is noted that a correction ratio for correcting the turning angle corresponding to the rotation amount of the steering wheel <NUM> may be a fixed value. Alternatively, the correction ratio may be determined based on at least one of the amount of deviation, the vessel speed, and the engine rotation speed. As a result, even when the steering wheel <NUM> is rotationally operated, the deviation decreases, thereby making it possible to prevent a sudden change in the turning angle at the time of returning to the normal steering mode, and to smoothly perform the shift to the normal steering mode.

After step S305 or S306, the controller <NUM> returns the processing to step S301.

In a case where the controller <NUM> determines, in step S303, that there is no deviation between the acquired steering angle and the actual turning angle, the processing proceeds to step S307. In step S307, the controller <NUM> starts the normal steering mode (the time point T6). Therefore, a case in which the processing proceeds to step S307 after step S304 is a case in which the normal steering mode is started after the deviation is eliminated by the control for reducing the deviation. Therefore, it is possible to suppress an uncomfortable feeling in the steering operation at the start of the normal steering mode.

When the controller <NUM> starts the normal steering mode, the controller <NUM> issues, in step S308, a notification of that normal steering mode is started. As a result, the vessel operator can be notified of the return to the normal steering mode. After step S308, the controller <NUM> ends the normal steering mode return processing (in <FIG>).

It is noted that, according to the normal steering mode return processing, in a case where after the control during stop is started, the steering wheel <NUM> starts rotating before the deviation is eliminated, the control during stop is terminated and the control during rotation is executed (S305 → S304 of the next loop → S306). On the other hand, in a case where after the control during rotation is started, the steering wheel <NUM> stops the rotation thereof before the deviation is eliminated, the control during rotation is terminated and the control during stop is executed (S306 → S304 of the next loop → S305). Therefore, even when the steering wheel <NUM> are repeatedly rotated and stopped rotating, it is possible to suppress an uncomfortable feeling in the steering operation at the start of the normal steering mode by eliminating the deviation.

According to the present preferred embodiment, for the steering wheel <NUM>, a rotatable angle in the left rotation direction is regulated to the first angle position θL, and a rotatable angle in the right rotation direction is regulated to the second angle position θR. The controller <NUM> performs control to shift the steering mode to the normal steering mode in response to a change in the steering angle beyond the threshold angle TH in the AP mode (S203 → S207). In the normal steering mode, the controller <NUM> switches the steering mode to the AP mode when the steering angle is within the shiftable range (the angle θ14 and the angle θ16) and does not switch the steering mode to the AP mode when the steering angle falls within the shift prohibition ranges θ13 and θ15 (S105). As a result, in the AP mode, a state in which the rotation operation beyond the threshold angle TH is possible is secured anytime. Therefore, in the AP mode, the vessel operator can anytime cancel the AP mode by performing rotation operation on the steering wheel <NUM>.

In addition, in a case where the start instruction of the AP mode is acquired, and the AP shift condition is not satisfied and the steering mode is not shifted to the AP mode, the controller <NUM> issues a notification of that matter (S108 and S110), so that the vessel operator can be notified of that the steering mode cannot be shifted to the AP mode. At this time, the controller <NUM> issues a notification to urge the vessel operator to return the steering wheel <NUM> to the neutral position, and thereafter, when the AP shift condition is satisfied within the second predetermined period of time, the steering mode is shifted to the AP mode. Therefore, when the steering wheel <NUM> is positioned in the shiftable range within the second predetermined period of time, the controller <NUM> can shift the steering mode to the AP mode even if there is no start instruction again (S109 → S105 → S106).

In addition, since the shift prohibition range is determined based on at least one of the vessel speed and the engine rotation speed (S104), the shift to the AP mode can be smoothly performed.

In addition, when the vessel operator is notified of that the steering mode has been shifted to the AP mode, the operator is notified to return the steering wheel <NUM> to the neutral position (S201), thereby making it possible to reduce deviation between the turning angle corresponding to the steering angle and the actual turning angle of the outboard motor <NUM>. Therefore, it is possible to suppress an uncomfortable feeling in the steering operation at the time of returning to the normal steering mode. Moreover, the operators disposed on the steering wheel <NUM> can be easily operated in the AP mode.

Further, in the AP mode, when the steering wheel <NUM> is located in the neutral range, a load to be applied on the steering wheel <NUM> performing the rotation operation thereof is controlled to be larger than a load to be applied when the steering wheel is not located in the neutral range (S206), so that the steering wheel <NUM> is easily maintained in the neutral range.

Additionally, in the AP mode, when the steering wheel <NUM> is rotationally operated in the direction away from the neutral range, the generated load is increased as compared with a case in which the steering wheel is rotationally operated in the direction approaching the neutral range (S209 and S210). Accordingly, it is possible to tactilely urge the vessel operator to return the steering wheel <NUM> to the neutral range.

According to the present preferred embodiment, in the return processing for shifting the steering mode from the AP mode to the normal steering mode, the controller <NUM> controls the turning actuator <NUM> so as to reduce the deviation between the turning angle corresponding to the steering angle and the actual turning angle of the outboard motor <NUM> when the steering wheel <NUM> is in the rotationally stopped state (control during stop (first control); S305).

As a result, even if the steering operation is not performed, the deviation becomes small by the time of returning to the normal steering mode, and therefore it possible to suppress an uncomfortable feeling in the steering operation after the AP mode is cancelled.

In addition, in the control during stop (S305), the change amount Δ per unit period of time of the turning angle of the outboard motor <NUM> is determined based on the amount of deviation, which makes it possible to eliminate an uncomfortable feeling in the steering operation at an appropriate speed. In addition, the change amount Δ is determined so as to eliminate the deviation within the target period of time, which makes it possible to eliminate the uncomfortable feeling in the steering operation within the target period of time.

Alternatively, in the control during stop (S305), the change amount Δ is determined based on at least one of the vessel speed and the engine rotation speed, which makes it possible to smoothly perform the shift to the normal steering mode.

Further, after the normal steering mode return processing (in <FIG>) is started, the normal steering mode is started while the normal steering mode return processing is terminated, when the deviation is eliminated (S307), which makes it possible to suppress the uncomfortable feeling in the steering operation at the start of the normal steering mode.

Additionally, when the normal steering mode is started, that matter is notified (S308), the vessel operator can be notified of the return to the normal steering mode.

Further, when the steering wheel <NUM> is not in the rotationally stopped state, the controller <NUM> performs the control during rotation (second control; S306). In the control during rotation, when the steering wheel <NUM> rotates in a direction in which the turning angle corresponding to the steering angle is away from/approaches the actual turning angle, the controller <NUM> changes the actual turning angle by a value obtained by correcting the turning angle corresponding to the rotation amount of the steering wheel <NUM> to a larger/smaller value. As a result, the shift to the normal steering mode can be smoothly performed.

Further, in the normal steering mode return processing even when the steering wheel <NUM> are repeatedly rotated and stopped rotating, the controller <NUM> switches the control between the control during stop and the control during rotation, thereby appropriately eliminating the deviation (S304 to S306). As a result, it is possible to suppress an uncomfortable feeling in the steering operation at the start of the normal steering mode.

In addition, the normal steering mode return processing (in <FIG>) is started in response to a cancellation instruction of the AP mode by operation on the changeover switch <NUM> or in response to a change in the steering angle beyond the threshold angle TH (S203 → S207). Therefore, in a situation where the vessel operator has an intention to perform manual steering and there is a possibility that deviation occurs, it is possible to start the return processing and reduce the deviation.

In addition, the normal steering mode return processing (<FIG>) is started in response to the return to a state in which both the steering angle and the actual turning angle can be acquired before the lapse of the first predetermined period of time after a state where the steering angle and/or the actual turning angle cannot be acquired occurred in the normal steering mode (S102 → S207). As a result, it is possible to start the return processing in a situation where there is a possibility that deviation occurs and to reduce the deviation.

Although the present invention has been described in detail based on the preferred embodiments thereof, the present invention is not limited to these specific preferred embodiments.

The present invention can also be implemented by performing processing in which a program adopted to implement one or more functions of the above-described preferred embodiments is supplied to a system or a device via a network or a non-transitory storage medium, and one or more processors of a computer of the system or the device read and execute the program. The above program and the storage medium storing the above program constitute the present invention. Further, the present invention can also be implemented by a circuit (for example, ASIC) adopted to implement one or more functions.

It is noted that the propulsion device is not limited to one having an engine as power, and an electric motor as power may be used for the propulsion device.

It is noted that the marine vessel to which the present invention is applied may be a marine vessel equipped with an inboard motor or an inboard/outboard motor, or a jet boat.

Claim 1:
A steering control device of a marine vessel (<NUM>), wherein the marine vessel includes a hull, a propulsion device that propels the hull, a steering wheel (<NUM>) having a regulated rotatable angle, and a turning driver (<NUM>) that changes a turning angle of the propulsion device (15A, 15B) the steering control device comprising:
at least one memory that stores a set of instructions; and
at least one processor that executes the instructions to:
control a steering mode of the marine vessel, the steering mode including a normal steering mode which allows the marine vessel to be steered by a rotation operation of the steering wheel, and an automatic steering mode which allows the marine vessel to be automatically steered without depending on the rotation operation of the steering wheel;
acquire a rotation angle position of the steering wheel;
acquire an actual turning angle of the propulsion device;
characterized in that, said at least one processor further executes the instructions to:
determine, based on the acquired rotation angle position, whether or not rotation of the steering wheel is stopped; and
when performing the control of the steering mode, during return control to shift the steering mode from the automatic steering mode to the normal steering mode, execute first control to control the turning driver so as to reduce deviation between a turning angle corresponding to the acquired rotation angle position and the acquired actual turning angle in a case where it is determined that the rotation of the steering wheel is stopped.