Steering control device that makes control of a steering mode of marine vessel, method thereof, and marine vessel

1 . A steering control device for a marine vessel including a steering wheel having a rotatable angle in a left rotation direction limited to a first angle position, and a rotatable angle in a right rotation direction limited to a second angle position, the marine vessel including steering modes including a normal steering mode and an automatic steering mode, the steering control device comprising:

at least one memory to store a set of instructions; and at least one processor configured or programmed to execute the set of instructions to:

acquire a rotation angle position of the steering wheel;

acquire a start instruction of the automatic steering mode to allow the marine vessel to be automatically steered without depending on a rotation operation of the steering wheel and automatically steered without depending on input by a vessel user; and

perform a control operation to shift the steering mode to the automatic steering mode in response to acquisition of the start instruction in the normal steering mode, and to shift the steering mode to the normal steering mode in response to a change in the rotation angle position of the steering wheel beyond a threshold angle in the automatic steering mode; wherein

during the control operation, in the normal steering mode, the at least one processor is configured or programmed to not shift the steering mode to the automatic steering mode even when the start instruction is acquired in a case where a difference between the acquired rotation angle position of the steering wheel and the first angle position is smaller than a first predetermined angle amount, or in a case where a difference between the acquired rotation angle position of the steering wheel and the second angle position is smaller than a second predetermined angle amount.

2 . The steering control device according to claim 1 , wherein the at least one processor is further configured or programmed to execute the set of instructions to:

in a case where the start instruction is acquired and the steering mode is not shifted to the automatic steering mode, provide notification that the steering mode is not shifted to the automatic steering mode.

3 . The steering control device according to claim 2 , wherein the at least one processor is further configured or programmed to execute the set of instructions to:

when providing notification that the steering mode is not shifted to the automatic steering mode, issue a notification to return the steering wheel to a neutral position between the first angle position and the second angle position.

4 . The steering control device according to claim 3 , wherein the at least one processor is further configured or programmed to execute the set of instructions to:

shift the steering mode to the automatic steering mode in a case in which the difference between the acquired rotation angle position of the steering wheel and the first angle position is equal to or greater than the first predetermined angle amount and the difference between the acquired rotation angle position of the steering wheel and the second angle position is equal to or greater than the second predetermined angle amount within a predetermined period of time after issuing the notification to return the steering wheel to the neutral position.

5 . The steering control device according to claim 1 , wherein the at least one processor is further configured or programmed to execute the set of instructions to:

determine the first predetermined angle amount and the second predetermined angle amount based on at least one of a vessel speed and a rotation speed of a drive source in a propulsion device to propel the marine vessel.

6 . The steering control device according to claim 1 , wherein the at least one processor is further configured or programmed to execute the set of instructions to:

in a case where the steering mode is shifted to the automatic steering mode, provide notification that the steering mode is shifted to the automatic steering mode.

7 . The steering control device according to claim 6 , wherein the at least one processor is further configured or programmed to executes the set of instructions to:

when notifying that the steering mode is shifted to the automatic steering mode, issue a notification to return the steering wheel to a neutral position between the first angle position and the second angle position.

8 . The steering control device according to claim 1 , further comprising:

a load generator to generate a load acting on the steering wheel performing the rotation operation thereof; wherein

the at least one processor is further configured or programmed to execute the set of instructions to:

after the steering mode is shifted to the automatic steering mode, in a case where the steering wheel is located in a predetermined range having a neutral position as a reference position, which is located between the first angle position and the second angle position, control the load generator so that a load acting on the steering wheel performing the rotation operation thereof becomes larger than that in a case where the steering wheel is not located in the predetermined range.

9 . The steering control device according to claim 1 , further comprising:

a load generator to generate a load acting on the steering wheel performing the rotation operation thereof; wherein

the at least one processor is further configured or programmed to execute the set of instructions to:

after the steering mode is shifted to the automatic steering mode, in a case where the steering wheel is rotationally operated in a direction away from a predetermined range having a neutral position as a reference position, which is located between the first angle position and the second angle position, control the load generator so that a load to be generated becomes larger than that in a case where the steering wheel is rotationally operated in a direction approaching the predetermined range.

10 . The steering control device according to claim 1 , wherein the rotatable angle in the left rotation direction plus the rotatable angle in the right rotation direction is less than 360°.

11 . A marine vessel comprising:

a steering control device;

a steering wheel having a rotatable angle in a left rotation direction limited to a first angle position, and a rotatable angle in a right rotation direction limited to a second angle position, and including steering modes including a normal steering mode and an automatic steering mode;

at least one memory to store a set of instructions; and

at least one processor configured or programmed to execute the set of instructions to:

acquire a rotation angle position of the steering wheel;

acquire a start instruction of the automatic steering mode to allow the marine vessel to be automatically steered without depending on a rotation operation of the steering wheel and automatically steered without depending on input by a vessel user; and

perform a control operation to shift the steering mode to the automatic steering mode in response to acquisition of the start instruction in the normal steering mode, and to shift the steering mode to the normal steering mode in response to a change in the rotation angle position of the steering wheel beyond a threshold angle in the automatic steering mode; wherein

during the control operation, in the normal steering mode, the at least one processor is configured or programmed to not shift the steering mode to the automatic steering mode even when the start instruction is acquired in a case where a difference between the acquired rotation angle position of the steering wheel and the first angle position is smaller than a first predetermined angle amount, or in a case where a difference between the acquired rotation angle position of the steering wheel and the second angle position is smaller than a second predetermined angle amount.

12 . The marine vessel according to claim 11 , wherein the rotatable angle in the left rotation direction plus the rotatable angle in the right rotation direction is less than 360°.

13 . A steering control method for a marine vessel including a steering wheel having a rotatable angle in a left rotation direction limited to a first angle position, and a rotatable angle in a right rotation direction limited to a second angle position, the marine vessel including steering modes including a normal steering mode and an automatic steering mode, the steering control method comprising:

acquiring a rotation angle position of the steering wheel;

acquiring a start instruction of the automatic steering mode to allow the marine vessel to be automatically steered without depending on a rotation operation of the steering wheel and automatically steered without depending on input by a vessel user; and

performing a control operation to shift the steering mode to the automatic steering mode in response to acquisition of the start instruction in the normal steering mode, and to shift the steering mode to the normal steering mode in response to a change in the rotation angle position of the steering wheel beyond a threshold angle in the automatic steering mode; wherein

during the control operation, in the normal steering mode, controlling so as not to shift the steering mode to the automatic steering mode even when the start instruction is acquired in a case where a difference between the acquired rotation angle position of the steering wheel and the first angle position is smaller than a first predetermined angle amount, or in a case where a difference between the acquired rotation angle position of the steering wheel and the second angle position is smaller than a second predetermined angle amount.

14 . The steering control method according to claim 13 , wherein the rotatable angle in the left rotation direction plus the rotatable angle in the right rotation direction is less than 360°.