Ship steering system

Abstract

[Problem] To control translational movement of a hull with a simple operation performed by operating a pair of azimuth thrusters (thrusters) with a single maneuvering device. [Solution] In a translational movement mode of the ship maneuvering system comprising a pair of thrusters 10, 10 provided symmetrically with respect to the center line of a hull 7, a maneuvering device 9 that outputs a first maneuvering quantity η instructing the direction of travel of the hull 7 and a second maneuvering quantity H instructing a change in the speed of the ship, and a control device 8, a target thrust of the hull is determined according to the first maneuvering quantity and the second maneuvering quantity, and a combination of thruster orientations α, β and thruster thrusts Tl, Tr of the pair of thrusters that produces the target thrust is calculated and selected.

Description

Technical Field

[0001] The present invention relates to a ship steering system that controls a pair of azimuth thrusters provided on a hull by operating an operating device, and more particularly to a ship steering system having a parallel movement mode for controlling the pair of azimuth thrusters so that the hull moves parallel.

[0002] In the present application, the azimuth thruster (hereinafter also referred to as "thruster") is a propulsion device of a ship using a propeller driven by an output shaft of an engine or an electric motor, and the propeller can rotate 360 degrees in all directions around a vertical axis perpendicular to the propeller shaft, and is provided with a mechanism capable of setting the driving force by the propeller in any direction of all directions.

Background Art

[0003] Patent Document 1 discloses an invention of a ship propulsion control device aimed at easily changing a ship operation pattern and realizing a hull behavior desired by a user. The ship propulsion control device 5 according to this invention has a control unit 10 and an input device 11. The control unit 10 includes a storage unit that stores a plurality of ship operation patterns set corresponding to a plurality of combinations of three propulsion devices 3A, 3B, 3C and three operation devices 4A, 4B, 4C, and specifies and reads out one ship operation pattern from these plurality of ship operation patterns based on selection information, and based on the read ship operation pattern, outputs command signals to the propulsion devices 3A, 3B, 3C according to the operation signals of the operation devices 4A, 4B, 4C.

[0004] Patent Document 2 discloses an invention of a steering system for a ship equipped with two propulsion systems at the stern, namely a portside propulsion system consisting of a portside thruster and a portside rudder, and a starboard side propulsion system consisting of a starboard side thruster and a starboard side rudder, which is steered by operating a joystick and a dial. According to this invention, the forward or backward thrust of the ship is obtained by the difference in the forward and backward thrusts of the portside and starboard side propulsion systems of the portside thruster and the starboard side thruster, and the first turning moment of the ship generated by these thrusts is canceled by the second turning moment of the ship generated by taking the rudder of the propulsion system on one side, so that while avoiding the rotation of the ship, it is possible to perform control to make the ship move parallel to the other side. According to this invention, it is said that high maneuverability can be exhibited in the operation of the ship.

[0005] Patent Document 3 discloses an invention of a steering device for a ship that controls a pair of azimuth thrusters. The steering device according to this invention includes a pair of forward and backward handles 6 and 7 on the left and right, a turning handle 1, and a pair of prime mover control knobs 31 and 32 provided on the pair of forward and backward handles 6 and 7. By operating this steering device, it is possible to perform accurate and rapid ship handling by combining the operation of turning the ship, the operation of moving the ship forward and backward, and the operation of individually controlling the thrusts of the pair of azimuth thrusters.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] Workboats such as tagboards generally have a plurality of propulsion devices, and by individually controlling the operation of each propulsion device, the hull can be moved arbitrarily. Although the inventions disclosed in Patent Documents 1 to 3 described above all control the movement of the hull by controlling a plurality of propulsion devices, as will be described below, if the number of propulsion devices to be controlled and the number of control devices are large, the number of combinations of the operations of the propulsion devices for realizing one hull behavior increases, and there is a common problem that the operation becomes complicated.

[0008] The invention disclosed in Patent Document 1 is supposed to simplify the operation by arbitrarily selecting a maneuvering pattern, but it requires a complicated operation of preparing a plurality of maneuvering patterns in advance and also requires a thorough understanding of the contents of the plurality of maneuvering patterns before the operation. That is, the system is complicated, and there is a problem that it is not always easy to select the optimal maneuvering pattern from among the plurality of maneuvering patterns in actual ship operation.

[0009] The invention disclosed in Patent Document 2 is supposed to control the operations of a pair of propulsion devices and a rudder by operating a joystick and a dial, and to exhibit high maneuverability with simple operation. However, there is a need for the operation of two types of control devices, that is, the traveling direction is operated by the joystick and the turning (heading or course change) is operated by the dial, and the operation is not necessarily simple. In addition, there is a problem that it is necessary to set the operations of the propulsion devices and the rudder in the control device for each operation of the hull.

[0010] The invention disclosed in Patent Document 3 requires the operation of a pair of forward and backward handles on the left and right and a turning handle to operate a pair of azimuth thrusters, and there is a problem that the operation is complicated.

[0011] The present invention is made to solve the problems in the above-described conventional technology, and aims to provide a ship steering system capable of easily controlling the parallel movement of a hull by controlling a pair of azimuth thrusters provided on the hull with a single steering device and switching the steering mode.

Means for Solving the Problems

[0012] The ship steering system according to claim 1 includes a pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, a control device that controls the azimuth thruster by operating the steering device, and is a ship steering system comprising the control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel, in the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device, and calculates and selects a combination of a thruster azimuth α and a thruster azimuth β of the pair of azimuth thrusters and a thruster thrust Tl and a thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust. and in the parallel movement mode, the control device combines the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull with the lateral component Fx and the fore-and-aft component Fy of the target thrust and the angle θ from the straight line connecting the center of gravity of the hull and the turning center of the thruster of the azimuth thruster to the center line of the hull and calculates according to (Relationship Formula 1) Fxcos α - Fxsin(α - θ) / (tan βcos θ + sin θ) = Fysin α - Fysin(α - θ) / (cos θ + sin θ / tan β) 。

[0013] The ship steering system according to claim 2 a pair of azimuth thrusters provided on the hull so as to be symmetrical about the center line of the hull a steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull a control device that controls the azimuth thruster by operating the steering device A ship steering system comprising the control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel in the parallel movement mode, the control device determines the target thrust of the hull according to the first operation amount and the second operation amount of the steering device calculates and selects a combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust in the parallel movement mode, the control device selects, from among the combinations of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull a combination such that the larger one of the value of the thruster azimuth difference |α2 - α1|, which is the difference between the current value α1 of the thruster azimuth when operating the steering device and the thruster azimuth α2 after operating the steering device, and the value of the thruster azimuth difference |β2 - β1|, which is the difference between the current value β1 of the thruster azimuth when operating the steering device and the thruster azimuth β2 after operating the steering device, is minimized 。

[0014] The ship steering system according to claim 3 is, a pair of azimuth thrusters provided on the hull so as to be symmetrical about the center line of the hull a steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull A control device that controls the azimuth thruster by operating the control device; A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel; In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the control device; Calculate and select a combination of the thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust; In the parallel movement mode, the control device From the combination of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull, The value of the thruster azimuth difference |α2 - α1|, which is the difference between the current value α1 of the thruster azimuth when operating the control device and the thruster azimuth α2 after operating the control device, The value of the thruster azimuth difference |β2 - β1|, which is the difference between the current value β1 of the thruster azimuth when operating the control device and the thruster azimuth β2 after operating the control device, The value of the thruster thrust difference |Tl2 - Tl1|, which is the difference between the current value Tl1 of the thruster thrust when operating the control device and the thruster thrust Tl2 after operating the control device, Among the values of the thruster thrust difference |Tr2 - Tr1|, which is the difference between the current value Tr1 of the thruster thrust when operating the control device and the thruster thrust Tr2 after operating the control device, Select a combination such that the maximum value is minimized 。

[0015] The ship steering system according to claim 4 is, A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull; A control device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull; A control device that controls the azimuth thruster by operating the control device; A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel; In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the control device; Calculate and select the combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters, and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust. In the parallel movement mode, the control device From the combination of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull The estimated arrival time required to change from the thruster azimuth α1 when operating the steering device to the thruster azimuth α2 after operating the steering device, The estimated arrival time required to change from the thruster azimuth β1 when operating the steering device to the thruster azimuth β2 after operating the steering device, The estimated arrival time required to change from the thruster thrust Tl1 when operating the steering device to the thruster thrust Tl2 after operating the steering device, Among the estimated arrival times required to change from the thruster thrust Tr1 when operating the steering device to the thruster thrust Tr2 after operating the steering device Select a combination such that the maximum value is minimized 。

[0016] The ship steering system according to claim 5 is A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, A steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, A control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel. In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device. Calculate and select the combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters, and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust. In the parallel movement mode, the control device From the combination of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull Select a combination such that the larger of the value of the thruster azimuth difference |α2 - α1|, which is the difference between the current value α1 of the thruster azimuth when operating the steering device and the thruster azimuth α2 after operating the steering device, and the value of the thruster azimuth difference |β2 - β1|, which is the difference between the current value β1 of the thruster azimuth when operating the steering device and the thruster azimuth β2 after operating the steering device, is minimized within a selectable range considering other factors excluding the time required for the azimuth thruster to turn. 。

[0017] The ship steering system according to claim 6 is A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, A steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsive force of the hull, A control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel, In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device, Calculates and selects a combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust, In the parallel movement mode, the control device By increasing or decreasing the fore-and-aft component of the thruster azimuth and the thruster thrust in accordance with an increase or decrease in the second operation amount by the same control as when the hull moves forward or backward, as reference values of left-right symmetry of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters, the thruster azimuth α0 and the thruster thrust Tl0 of the azimuth thruster on the port side of the hull and the thruster azimuth β0 and the thruster thrust Tr0 of the azimuth thruster on the starboard side of the hull are calculated, From among the combinations of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull in the parallel movement mode Of the values of the thruster azimuth difference |α2 - α0|, which is the difference between the thruster azimuth α0 and the thruster azimuth α2 after operating the steering device, the value of the thruster azimuth difference |β2 - β0|, which is the difference between the thruster azimuth β0 and the thruster azimuth β2 after operating the steering device, the value of the thruster thrust difference |Tl2 - Tl0|, which is the difference between the thruster thrust Tl0 and the thruster thrust Tl2 after operating the steering device, and the value of the thruster thrust difference |Tr2 - Tr0|, which is the difference between the thruster thrust Tr0 and the thruster thrust Tr2 after operating the steering device, select a combination such that the maximum value is minimized 。

[0018] The ship steering system according to claim 7 is the ship steering system described in claim to 1 In In the parallel translation mode, the control device modifies the magnitude of the target thrust according to the value of the first operation amount, calculates and selects a combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the modified target thrust, 。

[0019] The ship steering system according to claim 8 is a pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, a control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: The control device includes a parallel translation mode for controlling the azimuth thruster so that the hull moves in parallel, In the parallel translation mode, the control device determines the target thrust of the hull according to the first operation amount and the second operation amount of the steering device, calculates and selects a combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust, In the parallel translation mode, the control device when the state in which the same first operation amount and second operation amount are output from the steering device exceeds a predetermined period, Among the combinations of the thruster azimuth α, the thruster azimuth β, the thruster thrust Tl, and the thruster thrust Tr that generate the target thrust, select another combination in which the sum of the thruster thrust Tl and the thruster thrust Tr is smaller, and change from the current combination to the other combination 。

[0020] The ship steering system according to claim 9 is the ship steering system according to claim to 1 described, in which The steering device can output a third operation amount for instructing turning of the hull or a change in the hull azimuth, In the parallel movement mode, the control device changes at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters according to the third operation amount output from the steering device 。

[0021] The ship steering system according to claim 10 is a pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a steering device that outputs a first operation amount for instructing the traveling direction of the hull and a second operation amount for instructing the propulsion force of the hull, a control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel, In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device, The combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β is calculated and selected so as to obtain the target thrust, The steering device can output a third operation amount for instructing the turning of the hull or the change of the hull azimuth, In the parallel movement mode, the control device changes at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters according to the third operation amount output from the steering device and and the change is the combination of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull, the lateral component Fx and the fore-and-aft component Fy of the target thrust, the angle θ from the straight line connecting the center of gravity of the hull and the turning center of the thruster of the azimuth thruster to the center line of the hull, the target turning component M of the hull determined according to the third operation amount output from the steering device, (Relational expression 2) By calculating by {-Fy(tanβcos θ+sin θ) +M} / {sin(α-θ) -cos α(tanβcos θ+sin θ)}={-Fx(cosθ+sin θ / tanβ) +M} / { sin( α-θ) - sinα(cosθ+sin θ / tanβ)} 。

[0022] The ship steering system according to claim 11 is a pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a steering device that outputs a first operation amount for instructing the traveling direction of the hull and a second operation amount for instructing the propulsion force of the hull, a control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: The control device includes a translational movement mode for controlling the azimuth thruster so that the hull moves translationally. In the translational movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device. The control device calculates and selects a combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust. The steering device can output a third operation amount for instructing a turning of the hull or a change in the hull azimuth. In the translational movement mode, the control device changes at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters according to the third operation amount output from the steering device. And the change is a combination of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull. is a transverse component Fx' and a fore-and-aft component Fy' of a target thrust obtained by reducing the target thrust of the hull determined according to the first operation amount and the second operation amount. is an angle θ from a straight line connecting the center of gravity of the hull and the turning center of the thruster of the azimuth thruster to the center line of the hull. is a target turning component M of the hull determined according to the third operation amount output from the steering device. By calculating according to the relational expression 2 {-Fy'(tanβcos θ + sin θ) + M} / {sin(α - θ) - cos α(tanβcos θ + sin θ)} = {-Fx'(cosθ + sin θ / tanβ) + M} / {sin(α - θ) - sinα(cosθ + sin θ / tanβ)}. 。

[0023] The ship steering system according to claim 12 is the ship steering system according to claim 9 wherein In the translational movement mode, the control device changes the thruster azimuth of the pair of azimuth thrusters to an angle at which the turning component becomes larger. changes the thruster thrust of the pair of azimuth thrusters according to the magnitude of the target turning component. 。

[0024] The ship steering system according to claim 13 is the ship steering system according to claim 9 wherein is provided with a measuring device for measuring the hull azimuth. In the translational movement mode, the control device determines the turning component so that the difference between the hull azimuth measured by the measuring device and the target hull azimuth becomes zero. 。

[0025] The ship steering system according to claim 14 is a pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull. a steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull. A control device that controls the azimuth thruster by operating the control device; A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel. In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the control device. The thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters, and the combination of the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β are calculated and selected so as to obtain the target thrust. The control device can output a third operation amount for instructing turning of the hull or a change in the hull azimuth. In the parallel movement mode, the control device changes at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters according to the third operation amount output from the control device. The ship steering system further includes equipped with a measuring instrument for measuring the hull orientation, in the parallel movement mode, the control device makes the difference between the hull orientation measured by the measuring instrument and the target hull orientation zero, to the eye defines the yaw component, 、 and, in the parallel movement mode, the control device calculates the difference between the hull azimuth measured by the measuring instrument and the target hull azimuth. The target turning component is a value obtained by multiplying the difference by a coefficient and adding a value obtained by multiplying the time derivative of the difference by a coefficient. .

[0026] The ship steering system according to claim 15 is, A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull; A control device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull; A control device that controls the azimuth thruster by operating the control device; A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel. In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the control device. The thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters, and the combination of the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β are calculated and selected so as to obtain the target thrust. The control device can output a third operation amount for instructing turning of the hull or a change in the hull azimuth. In the parallel movement mode, the control device The at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters is changed by the third operation amount output from the steering device. The ship steering system further includes a measuring device that measures the hull azimuth. In the parallel movement mode, the control device determines a target turning component so as to make zero the difference between the hull azimuth measured by the measuring device and the target hull azimuth. Also, in the parallel movement mode, the control device calculates the difference between the hull azimuth measured by the measuring device and the target hull azimuth. The target turning component is a value obtained by multiplying a value obtained by subtracting the turning angular velocity from the value obtained by multiplying the difference by a coefficient by a coefficient. .

[0027] The ship steering system according to claim 16 is, A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, a control device that controls the azimuth thrusters by operating the steering device, A ship steering system comprising: The control device includes a parallel movement mode in which the azimuth thrusters are controlled so that the hull moves in parallel. In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device. A combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β is calculated and selected so as to obtain the target thrust. The steering device can output a third operation amount indicating turning of the hull or a change in the hull azimuth. In the parallel movement mode, the control device changes at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters by the third operation amount output from the steering device. The ship steering system further includes a measuring device that measures the hull azimuth. In the parallel movement mode, the control device determines a target turning component so as to make zero the difference between the hull azimuth measured by the measuring device and the target hull azimuth. Also, in the parallel movement mode, the control device When the third operation amount is output, determines the target turning component of the hull according to the third operation amount. When the third operation amount is not output, performs control to determine the target turning component so as to make zero the difference between the hull azimuth measured by the measuring device and the target hull azimuth. 。

[0028] The ship steering system according to claim 17 is the ship steering system according to claim 13 in the ship steering system described therein, In the parallel movement mode, the control device sets the hull orientation at at least one of the time point when switching to the parallel movement mode or the time point when the third operation amount becomes zero as the target hull orientation 。

[0029] The ship steering system according to claim 18 is a pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, a control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: The control device includes a parallel movement mode in which the azimuth thruster is controlled so that the hull moves in parallel, In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device, calculates and selects a combination of a thruster azimuth α and a thruster azimuth β of the pair of azimuth thrusters and a thruster thrust Tl and a thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust, The steering device includes a cruising mode in which the azimuth thruster is controlled so that the hull moves forward or backward. In the cruising mode, the reference values of the thruster azimuths of the pair of azimuth thrusters are symmetric with respect to the left and right, increases and decreases the forward and backward components of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters according to the increase and decrease of the second operation amount, by further increasing and decreasing the thruster azimuth set according to the second operation amount according to the increase and decrease of the first operation amount, the hull moves forward and backward, moves straight and turns, turns backward, and stops neutrally 。

[0030] The ship steering system according to claim 19 is the ship steering system according to claim 8 in the ship steering system described therein, The steering device can output a third operation amount for instructing a turning of the hull or a change in the hull orientation, In the cruising mode, the control device increases or decreases the thruster azimuth set according to the second operation amount according to the increase and decrease of the third operation amount instead of the first operation amount, or increases or decreases the thruster azimuth set according to the second operation amount according to the increase and decrease of the first operation amount, and then further increases or decreases according to the third operation amount。

[0031] The ship steering system according to claim 20 is the ship steering system according to claim 1 in the ship steering system described in At least one of the first operation amount and the second operation amount is remotely provided to the control device. 。

[0032] The ship steering system according to claim 21 is the ship steering system according to claim 20 in the ship steering system described in The hull is provided with a receiver of the remote control device, The transmitter of the remote control device is provided on the ship that the hull moves. 。

Advantages of the Invention

[0034] According to the invention of claim 1 to 21 For a ship equipped with a pair of azimuth thrusters provided symmetrically with respect to the center line of the hull, by using a single steering device that outputs at least a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, such as a joystick, etc., a simple operation can be performed, and the hull can be steered with high maneuverability, such as moving the hull in a parallel movement mode. As the operation of the azimuth thruster to be controlled, there are four types of operations: the thruster azimuth and the thruster thrust of a pair of azimuth thrusters provided on the hull, and there are many combinations of the four types of operations to realize one hull behavior. Therefore, the target thrust generated on the hull is determined by the first operation amount and the second operation amount output according to the operation of the steering device. Then, by calculating the combination of the four types of operations of the azimuth thruster that generates the target thrust and selecting an appropriate combination from them, the optimal operation of the pair of azimuth thrusters can be automatically selected and implemented for each operation of the steering device. Therefore, for example, in the case of a workboat such as a tag boat, the approach and departure from the shore and the positioning can be surely performed with a simple operation by the parallel movement of the hull in the parallel movement mode.

[0035] Claim 1According to the invention, given the angle θ which is a fixed value determined by the structure and equipment of the ship, and the transverse component Fx and the fore-and-aft component Fy of the target thrust determined by the first operation amount and the second operation amount output by the operation of the steering device, since the relationship between the azimuth α of the thruster on the port side and the azimuth β of the thruster on the starboard side is represented by relational expression 1, the combination of the thruster azimuth α and the thruster azimuth β can be calculated.

[0036] Claim 2 According to the invention, when the steering device is operated, the combination of the four types of operations of the azimuth thruster that generates the target thrust changes from the current state to the state after the operation. The greater the difference in the thruster azimuth due to this change, the more time and power are required to change the course or speed of the hull. Therefore, by selecting the combination of thruster azimuths such that the larger of the values of the thruster azimuth differences |α2 - α1| and |β2 - β1| between the current state and after the operation of the steering device is minimized, smooth and efficient steering can be performed.

[0037] The above-mentioned claim 2 The selection method of the invention only judges from the thruster azimuth. However, depending on the operation of the steering device, although the change in the thruster azimuth is small, the change in the thruster thrust may be large, and a lot of time and power may be required to change the course or speed of the hull. According to the invention of claim 3 not only the thruster azimuth differences |α2 - α1| and |β2 - β1| between the current state and after the operation of the steering device, but also the thruster thrust differences |Tl2 - Tl1| and |Tr2 - Tr1| between the current state and after the operation of the steering device are targeted, and by selecting the combination of thruster azimuths such that the largest value among these is minimized as a ratio, smooth and efficient steering can be performed.

[0038] The above-mentioned claim 3 The selection method of the invention is a method of selecting a combination that minimizes the changes in the thruster azimuth and the thruster thrust. However, since the time required to reach the thruster azimuth and the thruster thrust after the operation depends on the acceleration and deceleration ability of the propeller rotation speed and the nozzle turning ability, it is not a method that minimizes the time required for the change. Therefore, claim Item 4The invention can perform smooth maneuvering by selecting a combination of thruster orientations such that the thruster orientation and thruster thrust after the operation of the maneuvering device from the current state, i.e., the estimated time to reach until the target is minimized.

[0039] In the selection method of the invention described above in the claims 2 a combination of thruster orientations that minimizes the thruster orientation difference will be selected. However, just because the change in the thruster orientation α or β becomes smaller, for example, if a combination is selected such that a pair of azimuth thrusters face inward (the direction in which the propellers face each other), there is a possibility that the azimuth thrusters may malfunction due to the collision of the two water flows, and there is also a possibility that the hull vibrates and damages the hull. Also, since the thrusts of the azimuth thrusters cancel each other out, the efficiency is poor. Furthermore, claims also include combinations that are not realistic or technically impossible, such as combinations where the thruster thrust is extremely large or the thruster thrust becomes negative. 5 According to the invention, by selecting a combination with a smaller change in the thruster orientations α and β from the range limited to realistically selectable combinations excluding such cases to be avoided, smooth maneuvering can be performed without causing adverse situations in terms of mechanical effects and efficiency.

[0040] In the selection method of the invention described above in the claims 3 a combination of thruster orientations is selected based on the values of the thruster orientation differences |α2 - α1| and |β2 - β1| between the current state and after the operation of the maneuvering device, and the thruster thrust differences |Tl2 - Tl1| and |Tr2 - Tr1|. However, as another way of thinking, in the selection method of the invention of the claims 6 reference values are set for the thruster orientation and thruster thrust, and a combination of thruster orientations is selected based on the reference values. Specifically, it will be described later CruiseTaking α0 and β0, which are combinations of thruster azimuths that are symmetric left and right when moving forward and backward in the mode, and the corresponding thruster thrusts Tl0 and Tr0 as reference values, select a combination such that the largest value as a ratio is minimized for the thruster azimuth differences |α2 - α0|, |β2 - β0|, the thruster thrust differences |Tl2 - Tl0|, |Tr2 - Tr0|. As a result, the selection of the combination of thruster azimuths α, β, thruster thrusts Tl, Tr becomes independent of the progress of ship operation, reproducibility occurs in the selection, and the operation of the ship steering system becomes stable. Note that as a similar concept, in the invention of claim 2 , select a combination such that the largest value is minimized only for the thruster azimuth differences |α2 - α0|, |β2 - β0| without considering the thruster thrust difference, as in the invention of claim 4 , select a combination such that the largest of the estimated arrival times is minimized, as in the invention of claim 5 , it is also possible to select a combination within the selectable range when considering other elements, as in the invention of claim

[0041] Claim 7 According to the invention of claim, depending on the thruster azimuth η, the thruster thrusts Tl, Tr can be generated up to near their upper limits. Even in the parallel movement mode, the thruster thrusts Tl, Tr can be generated up to near the upper limit at the tipping azimuth angle η close to the forward or backward direction, enabling navigation up to near the maximum speed.

[0042] Claim 8According to the invention, by reselecting the combination of thruster azimuth and thruster thrust, it is possible to minimize the total thruster thrust while maintaining the target thrust. For example, in the case of a workboat such as a tagboat, it is assumed that the same operation is performed and the vessel sails in a translational mode for a certain period or more in order to move within the bay. As described above, when the control device selects a combination that minimizes the thruster azimuth difference before and after the operation, the total thruster thrust of that combination does not necessarily become the minimum, and if that state is maintained, it may be disadvantageous in terms of efficiency. Therefore, when the state in which the same first operation amount and second operation amount are output exceeds a predetermined period, another combination with a smaller total thruster thrust is selected, and the pair of azimuth thrusters is controlled so as to gradually change from the current combination to another combination, whereby the fuel consumption can be suppressed to a lower level while maintaining the target thrust. Although it is also possible to immediately change from the current combination to another combination, by gradually changing, it is possible to smoothly shift to a combination in which the thrust is minimized.

[0043] The hull orientation may change due to disturbances such as hydrodynamic forces acting on the hull and wind. According to the invention of claim 9, by operating the steering device, a third operation amount for instructing the turning of the hull or the change in hull orientation is output from the steering device to the control device, and by changing the azimuth or thrust of the thruster of one or both of the azimuth thrusters, the hull orientation changed due to disturbances such as hydrodynamic forces and wind can be corrected.

[0044] The combination of thruster azimuth α and thruster azimuth β that generates the target thrust can be calculated from relational expression 1, but the hull orientation may change due to disturbances such as hydrodynamic forces acting on the hull and wind. Claim 10According to the invention, by determining the target turning component M generated in the hull by the third operation amount, and giving the target turning component, the angle θ which is a fixed value determined from the structure and equipment of the ship, and the transverse component Fx and the fore-and-aft component Fy of the target thrust determined by the first operation amount and the second operation amount output by the operation of the steering device, the relationship between the azimuth α of the thruster on the port side and the azimuth β of the thruster on the starboard side is represented by relational expression 2. By using relational expression 2 including the target turning component M for calculating the combination of the thruster azimuth α and the thruster azimuth β, it is possible to calculate the combination of the thruster azimuth α and the thruster azimuth β taking into account the correction of the hull azimuth.

[0045] The above-mentioned claim 9 and 10 In the invention, the correction of the hull azimuth is performed by causing a part of the thrust of the hull to act on the turning of the hull. Therefore, when a large fluid force or disturbance such as wind acts on the hull, the turning component required for correction also becomes large, and there may be a case where it exceeds the maximum thrust that the azimuth thruster can output. Claim 11 According to the invention, by reducing the target thrust of the hull determined according to the first operation amount and the second operation amount, and distributing the reduced amount of the target thrust to the turning component to obtain a turning component of a magnitude required for correction, it is possible to calculate the combination of the thruster azimuth and the thruster thrust in which the thruster thrust is below the maximum thrust.

[0046] The above-mentioned claim 11 is a method of distributing a part of the thrust that should originally be used for translation to the turning component while performing translation. However, even when the thrust used for translation is made as close to zero as possible, there may be a case where the hull azimuth cannot be corrected completely. Claim 12 According to the invention, by setting the thruster azimuth to an angle at which the turning component becomes larger (for example, an angle perpendicular to the angle θ from the straight line connecting the center of gravity of the hull and the turning center of the azimuth thruster to the center line of the hull), and changing the thruster thrust, it is possible to efficiently correct the hull azimuth.

[0047] The above-mentioned claim 9 to 12In the correction of the hull orientation of the invention, since it is necessary for the operator to visually check the hull orientation and operate the control device, a time delay occurs. Claim 13 According to the invention, the control device obtains the actual hull orientation from the navigation instruments installed on the hull, and determines the target turning component M so as to make the difference from the target hull orientation (hereinafter referred to as the azimuth angle deviation) zero, thereby realizing the correction of the hull orientation. In addition, since it does not pass through the operator, the occurrence of time delay can also be suppressed. This control is hereinafter referred to as azimuth angle control.

[0048] Claim 14 According to the invention, by performing azimuth angle PD control in which the target turning component is a value obtained by multiplying the azimuth angle deviation by a coefficient and further adding a value obtained by time-differentiating the azimuth angle deviation, the hull orientation can be corrected. Azimuth angle PD control is a control that combines the azimuth angle control (P control) with the turning angular velocity (D control) which is the differential component of the hull orientation, can predict the azimuth angle change, and can hold the azimuth quickly. Although the turning angular velocity of the hull orientation is calculated from the azimuth angle deviation, a measuring instrument for measuring the turning angular acceleration may be provided and used for control.

[0049] Claim 15 According to the invention, by the cascade control of the azimuth angle control and the turning angular velocity feedback, while approaching the hull orientation to the target hull orientation, the change in the hull orientation can be suppressed. Regarding the turning speed, a measuring instrument for measuring this may be provided, and when there is no measuring instrument for measuring the turning angular velocity, the azimuth angle deviation may be differentiated and used for control.

[0050] Claim 16 According to the invention, Claims 10 and Claim 11 such manual correction by the operator, and the azimuth angle control of Claim 13 or the azimuth angle PD control of Claim 14 or the cascade control of Claim 15 are combined, so that it is possible to automatically correct the hull orientation while manually correcting the hull orientation arbitrarily by the operator, and it is possible to shorten the time delay until correction while making a conscious azimuth correction.

[0051] In order to automatically correct the hull orientation, special operations such as the operator manually inputting the target value of the hull azimuth angle or setting the current hull azimuth as the target value by button operation are required. However, according to the claim 17 of the invention, when the operator looks at the hull orientation and the hull is facing the direction in which it wants to proceed, by setting the third operation amount to zero, the special operations as described above become unnecessary.

[0052] According to the claim 18 of the invention, the control device is provided with a cruising mode in which the hull can be arbitrarily maneuvered during medium and long-distance movement in addition to the parallel movement mode. Therefore, during medium and long-distance movement, the cruising mode is selected, and during approach and departure from the shore and positioning, the parallel movement mode is selected, so that navigation can be performed by fully utilizing the basic performance and functions of the ship according to the purpose of navigation or movement. Note that regardless of the operation mode, by setting the steering device to the neutral position (the first operation amount and the second operation amount are zero), the thruster azimuths of the pair of azimuth thrusters are set to the inward true beam, and the hull is kept in a stopped state with the thrust vectors of the pair of azimuth thrusters canceling each other while the thrusters are generating thrust, so that changes in the position and orientation of the hull due to external disturbances such as wind can be suppressed. Also, when the ship speed is a certain value, by setting it to this state, a braking force can be applied to the hull, and deceleration to a stop can be performed quickly.

[0053] According to the claim 19 of the invention, in the cruising mode, the ship can be steered by the third operation amount (the operation of turning the head of the handle) instead of the first operation amount (the operation of tilting the handle to a desired azimuth angle). Also, as an operation for changing the azimuth of the azimuth thruster by the first operation amount and the third operation amount, for example, while tilting the handle to indicate a turn (the first operation amount), if the hull azimuth deviates from the operator's intention, it can be corrected by turning the head of the handle (the third operation amount).

[0054] According to the claim 20According to the invention, since the first operation amount or the second operation amount can be remotely given to the control device, it is not necessary for the crew to board the hull and operate the control device to operate the ship. Even if the crew operating the control device is not on board the hull, the hull can be remotely and accurately maneuvered. Further, if desired, the third operation amount may be remotely given.

[0055] Claim 21 According to the invention, for example, by providing a receiver of the remote control device on a tugboat or an auxiliary ship such as a tagboard, and providing a transmitter of the remote control device on a large ship that cannot operate finely in a narrow place such as a tanker, the tugboat or the auxiliary ship can be remotely controlled from the large ship.

Brief Description of the Drawings

[0056]

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Figure 4C

Figure 5A

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Figure 5C

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Figure 16A

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Embodiments for Carrying Out the Invention

[0057] Embodiments of the ship steering system according to the present invention will be described with reference to FIGS. 1 to 18 (hereinafter, as necessary, for drawings with figure numbers including English characters, it is assumed that all drawings with the figure numbers including the English characters can be shown only by the numbers obtained by omitting the English characters). (I) Configuration of the Ship Steering System First, the configuration of the ship steering system 1 will be described with reference to FIGS. 1, 2A, 2B, and 2C. As shown in Fig. 1, the ship steering system 1 includes a pair of azimuth thrusters 10, 10 as a propulsion device having the function of a steering gear. The azimuth thruster 10 has a power transmission device and the above-described propeller turning device. The output shafts 6, 6 of the engines 5, 5 are respectively interlocked and connected to the power transmission device of the azimuth thruster 10 by clutches (not shown), and the driving force of the engine 5 is transmitted from the output shaft 6 to the propeller shaft 2 so that the propeller 3 can be driven. Note that the propeller 3 may be driven by an electric motor. The turning device of the azimuth thruster 10 is configured with a motor 4 as a drive source, and the driving force of the motor 4 is transmitted to the propeller 3 so that it can turn by a desired angle in a desired direction. Therefore, by controlling the engine 5, the desired propulsion force applied to the propeller 3 can be increased or decreased, and by controlling the motor 4, the propeller 3 can be turned around the vertical axis in all directions of 360 degrees.

[0058] As shown in Fig. 1, the pair of azimuth thrusters 10, 10 of the ship steering system 1 described above are provided at the rear of the hull 7 so as to be symmetric with respect to the center line CL of the hull 7 as shown in Figs. 2B and 2C.

[0059] As shown in Fig. 1, the ship steering system 1 includes a control device 8. The control device 8 can arbitrarily set the thrust (thruster thrust) of each azimuth thruster 10, 10 by controlling the engine 5 via the engine control unit 5a according to a command from the steering device 9, and can also arbitrarily set the azimuth angle (thruster azimuth) of the thruster thrust by controlling the motor 4 for turning the azimuth thruster 10. The control device 8 has two ship operation modes called a cruising mode and a parallel movement mode, and can control the azimuth thruster 10 by switching to the necessary mode. The details of these two ship operation modes will be described later. The cruising mode is a ship operation mode for facilitating operation when sailing a medium to long distance, etc., and the parallel movement mode is a ship operation mode that provides high maneuverability with a simple operation when approaching or leaving the shore and positioning, etc.

[0060] The steering device 9 provided in the ship steering system 1 shown in Fig. 1 is a joystick type device as shown in Fig. 2A. The rod-shaped handle 11 can tilt in any direction for 360 degrees in all directions. It is possible to output to the control device 8 a first operation amount that is a steering signal corresponding to the angle indicating the tilted direction of the handle 11 (the tilt azimuth angle η described later in the description regarding Fig. 11A) and that indicates the traveling direction of the hull, and also a second operation amount that is a steering signal corresponding to the tilt amount of the handle 11 in that direction (the tilt amount H described later in the description regarding Fig. 11A) and that indicates the propulsion force of the hull. Further, the grip portion 12 at the upper end of the handle 11 can rotate within a plane orthogonal to the longitudinal direction of the handle 11, and it is possible to output to the control device 8 a third operation amount that is a steering signal corresponding to the rotation angle (the twist angle Z of the handle 11 described later in the description regarding Fig. 15) and that indicates the turning of the hull or the change in the hull azimuth. In the embodiment, it is assumed that the first to third operation amounts can be output by a single steering device 9. However, the joystick may sense the tilt amount in the X-axis direction and the tilt amount in the Y-axis direction of the XY coordinate system shown in Fig. 2B described later by a potentiometer or the like provided respectively, and output the first and second operation amounts. Also, at least the first and second operation amounts may be output only by operating the stick-shaped handle by a joystick type steering device without the grip portion 12. In addition to this steering device, a second steering device using a dial operation type or two buttons for instructing left rotation and right rotation may be provided to output the third operation amount, or the grip portion 12 may be integrated with the handle 11, and the third operation amount may be output by twisting (rotating) the entire handle. Also, as long as it is a steering device that can output the first to third operation amounts, it may not be of the joystick type. Also, the steering device may be one that returns to the zero point and sets the operation amount to zero when the crew member (operator) releases the hand from the steering device, or one that maintains the previous operation amount without returning to the zero point.

[0061] In the embodiment, it is assumed that the first to third operation amounts can be output by a single steering device 9. However, the joystick may sense the tilt amount in the X-axis direction and the tilt amount in the Y-axis direction of the XY coordinate system shown in Fig. 2B described later by a potentiometer or the like provided respectively, and output the first and second operation amounts. Also, at least the first and second operation amounts may be output only by operating the stick-shaped handle by a joystick type steering device without the grip portion 12. In addition to this steering device, a second steering device using a dial operation type or two buttons for instructing left rotation and right rotation may be provided to output the third operation amount, or the grip portion 12 may be integrated with the handle 11, and the third operation amount may be output by twisting (rotating) the entire handle. Also, as long as it is a steering device that can output the first to third operation amounts, it may not be of the joystick type. Also, the steering device may be one that returns to the zero point and sets the operation amount to zero when the crew member (operator) releases the hand from the steering device, or one that maintains the previous operation amount without returning to the zero point.

[0062] The control device 9 of the ship steering system 1 shown in FIG. 1 is mounted on the hull 7 shown in FIG. 2B and is a device manually operated (steered) by the crew (operator) of the ship. However, as shown in FIG. 1, in addition to this manual control device 9, a receiver 16 of the remote control device 15 may be mounted on the hull 7. In this case, a transmitter 17 of the remote control device 15 is provided outside the hull 7, and a steering signal (the first to third operation amounts described above and other necessary signals) is given to the control device 8 by means of communication such as radio waves via the receiver 16 from outside the hull 7. The location where the transmitter 17 is provided may be another ship or any fixed or moving steering base provided in the sea, on the ground, in the air, or in outer space. Also, although not shown, measuring instruments, sensors, cameras, radars, sonars, etc., which monitor the speed of the hull 7, the hull orientation, the speed at which the hull orientation of the hull 7 changes (hereinafter referred to as the turning angular velocity), and the situation around the hull 7, etc., may be provided on the hull 7 as information acquisition means. When automatically correcting the hull orientation (details will be described later) or steering the hull 7 by the remote control device 15 using this information acquisition means, the information acquired by the information acquisition means may be remotely transmitted to another ship or a steering base where the transmitter 17 outside the hull 7 is installed. Note that the control device 9 and the remote control device 15 can be used by arbitrarily switching between them.

[0063] (II) Cruising mode and parallel movement mode Next, the ship handling function of the control device 8 in the ship steering system 1 will be described. The ship steering system 1 of the embodiment has a cruising mode and a parallel movement mode as the steering modes of the hull 7 as described above.

[0064] The cruising mode is a ship handling mode in which the forward movement (straight ahead, right turn, left turn), neutral stop, and backward movement (straight ahead, right turn, left turn) of the hull 7 are performed by operating the handle 11 and the grip portion 12 of the control device 9, and is mainly for the purpose of moving the ship over a medium to long distance.

[0065] The parallel movement mode is a ship operation mode in which the forward movement (straight ahead), backward movement (straight back), neutral stop of the hull 7, the lateral movement (left and right) that moves the hull 7 parallel in the left - right direction, and the diagonal movement that moves the hull 7 parallel in the diagonal direction are performed by operating the handle 11 of the steering device 9, mainly for the purpose of docking and positioning of the ship. In the parallel movement mode, when the orientation of the hull 7 changes during parallel movement, the orientation correction of the hull 7 can also be performed by operating the grip portion 12 of the handle 11 of the steering device 9.

[0066] In the following description, as the coordinate system indicating the thruster orientation of the azimuth thruster 10 and the traveling direction of the hull 7, the XY coordinate system shown in FIGS. 2B and 2C is used. Although this coordinate system is shown only in FIGS. 2B and 2C, the same coordinate system will be used for explanation in other figures. In this XY coordinate system, the straight - ahead direction of the hull 7 is the positive direction of the Y - axis, the starboard beam direction of the hull 7 is the positive direction of the X - axis, and the axis of rotation when the hull 7 turns or maneuvers is the Z - axis. The turning of the hull 7 around the Z - axis is represented with the positive direction of the Y - axis as 0 degrees, 0° to 180° clockwise, and 0° to - 180° counterclockwise. The origin of each coordinate axis is the center of gravity G of the hull 7.

[0067] (III) Explanation of the cruising mode The cruising mode will be described with reference to FIGS. 2 to 8. FIG. 2 is a diagram for explaining the forward movement in the cruising mode. When advancing the hull 7, the operator tilts the handle 11 of the steering device 9 forward as indicated by the arrow in FIG. 2A. The steering device 9 outputs a first operation amount and a second operation amount, which are steering signals corresponding to the tilt azimuth angle η and tilt amount H of the handle. The control device 8 changes the thruster orientation and thruster thrust according to the output signal of the steering device 9. For example, when the handle 11 is tilted forward to the maximum, that is, to the limit, the control device 8 sets the thruster orientation of the azimuth thrusters 10 on both sides to 0 degrees as shown in FIG. 2B, and the thruster thrust (or propeller rotation speed and engine output) on both sides is the same and maximum. Thereby, the hull can be advanced. When the steering wheel 11 is not tilted forward to the maximum extent, as shown in Fig. 2C, the control device 8 changes the thruster azimuth and thruster thrust of the azimuth thrusters 10 on both sides according to the tilt amount H. Specifically, the larger the tilt amount H, the smaller the thruster azimuth and the larger the thruster thrust. Here, reducing the thruster azimuth means approaching the thruster azimuth to 0 degrees. Therefore, the more the steering wheel 11 is tilted forward, the closer the thruster azimuth is to 0 degrees. Hereinafter, making the thruster azimuth of the pair of azimuth thrusters approach 0 degrees and generating a larger thrust in the forward direction is expressed as increasing the forward component of the thruster azimuth. Also, the smaller the tilt amount H, the larger the thruster azimuth and the smaller the thruster thrust are changed. Here, increasing the thruster azimuth means approaching the thruster azimuth to 90 degrees or -90 degrees. Therefore, the more the steering wheel 11 is raised, the closer the thruster azimuth is to 90 degrees or -90 degrees. When the tilt amount H of the steering wheel 11 is 0, the thruster azimuths are thruster azimuth α = 90 degrees and thruster azimuth β = -90 degrees, which are the initial values that are symmetric about the hull and in the lateral direction. By controlling the thruster azimuth and thruster thrust as described above, when the steering wheel 11 is changed from forward to reverse, the traveling direction of the hull can be changed quickly and smoothly.

[0068] Fig. 3 is a diagram for explaining straight-ahead turning during forward movement in the cruising mode. When it is desired to turn the hull 7 during forward navigation, the operator performs an operation of rotating the grip portion 12 of the steering wheel 11 of the control device 9 in a desired direction as indicated by the arrow in Fig. 3A, or an operation of tilting the steering wheel 11 of the control device 9 in a desired direction as indicated by the arrow in Fig. 3B. In Fig. 3A, the grip portion 12 is rotated to the left, and in Fig. 3B, the steering wheel 11 is tilted to the left. When the operation in Fig. 3A is performed, the second operation amount and the third operation amount are output from the control device 9, and when the operation in Fig. 3B is performed, the second operation amount and the first operation amount are output from the control device 9. In the cruising mode, both the first operation amount and the third operation amount can be handled interchangeably as operation amounts for instructing the hull to turn. The control device 8 calculates the thruster azimuths α and β in response to the output of the steering device 9. First, without using the received first operation amount or third operation amount, that is, with the tilt azimuth angle η or the handle torsion angle (rotation angle of the grip portion 12) Z set to zero, the forward components of the thruster azimuth and the thruster thrust are increased or decreased according to the tilt amount H in the same manner as when moving forward described above. Let the thruster azimuths obtained from only the tilt amount H be α' and β' respectively. From these α' and β', the control device 8 subtracts the values obtained by multiplying the received tilt azimuth angle η and torsion angle Z by coefficients A and B (0 ≤ A, B ≤ 1) respectively, as shown by the following equations, to calculate the thruster azimuths α and β. By changing to this thruster azimuth, the hull can be made to move straight and turn in an arbitrary direction by the operator. α = α’ - A·η - B·Z β = β’ - A·η - B·Z Note that by setting the coefficients by the control device 8 as follows, the operation method of the handle 11 can be made effective in either or both of FIGS. 3A and 3B. A = 1, B = 0: Only the tilt azimuth angle η is effective A = 0, B = 1: Only the torsion angle Z is effective A = 1, B = 1: Both the tilt azimuth angle η and the torsion angle Z are effective Also, the coefficients can be set to numerical values with decimal places. For example, A = 1, B = 0.1 By setting it like this, The operation of tilting the handle 11 in a desired direction: Basic turning operation The operation of rotating the grip portion 12 of the handle 11 in a desired direction: Fine adjustment And combined use is also possible. This is the same for the reverse turning described later.

[0069] For example, when the operation of FIG. 3B is performed, the control device 8 increases the forward component of the thruster azimuth and the thruster thrust according to the received tilt azimuth angle η and tilt amount H. The more the handle 11 is tilted, the closer the thruster azimuth approaches 0 degrees, and the more the handle 11 is raised, the closer the thruster azimuth approaches 90 degrees or -90 degrees. The tilt azimuth angle η is subtracted from the thruster azimuth α′, β′ as shown in the following formula to calculate the thruster azimuth. When the handle 11 is tilted forward diagonally by 10 degrees to the maximum, the thruster azimuth α′, β′ becomes 0 degrees and the tilt azimuth angle η becomes 10 degrees, so the thruster azimuth α, β becomes -10 degrees. α =α´-η β =β´-η Then, as shown in FIG. 3C, the thruster azimuth and thruster thrust on both sides are changed to generate a turning component as indicated by the arrow around the center of gravity G of the hull 7. Thereby, the hull can be turned in an arbitrary direction.

[0070] FIG. 4 is a diagram for explaining the reverse movement in the cruising mode. When the hull 7 is moved backward, the operator tilts the handle 11 of the control device 9 forward as indicated by the arrow in FIG. 4A. The control device 9 outputs a first operation amount and a second operation amount, which are control signals corresponding to the tilt azimuth angle η and tilt amount H of the handle, and the control device 8 changes the thruster azimuth and thruster thrust according to the output signal of the control device 9. For example, when the handle 11 is tilted forward to the maximum, the control device 8 sets the thruster azimuth of the azimuth thrusters 10, 10 on both sides to 180 degrees or -180 degrees as shown in FIG. 4B, and the thruster thrust on both sides is the same and maximum. Thereby, the hull can be moved backward. When the steering wheel 11 is not tilted backward to the maximum extent, the control device 8 receives a signal from the steering device 9 and, as shown in FIG. 4C, changes the thruster azimuths of the azimuth thrusters 10 on both sides according to the tilt amount H. Specifically, the larger the tilt amount H, the closer the thruster azimuth is to 180 degrees or -180 degrees, and the greater the thruster thrust. That is, the more the steering wheel 11 is tilted backward, the closer the thruster azimuth is to 180 degrees or -180 degrees. Hereinafter, the operation of bringing the thruster azimuths of the pair of azimuth thrusters closer to 180 degrees or -180 degrees to generate a greater thrust in the reverse direction is referred to as increasing the reverse component of the thruster azimuth. Also, the above-described forward component and reverse component are collectively referred to as the forward and reverse component. Further, the smaller the tilt amount H, the greater the thruster azimuth and the smaller the thruster thrust are changed. Here, increasing the thruster azimuth means bringing the thruster azimuth closer to 90 degrees or -90 degrees. Therefore, the more the steering wheel 11 is raised, the closer the thruster azimuth is to 90 degrees or -90 degrees. By controlling the thruster azimuth and thruster thrust as described above, when the steering wheel 11 is changed from reverse to forward, the traveling direction of the hull can be changed quickly and smoothly.

[0071] FIG. 5 is a diagram for explaining a reverse turn in the cruising mode. When it is desired to turn the hull 7 during reverse navigation, the operator performs an operation of rotating the grip portion 12 of the handle 11 of the steering device 9 in a desired direction as indicated by the arrow in FIG. 5A, or performs an operation of tilting the handle 11 of the steering device 9 in a desired direction as indicated by the arrow in FIG. 5B. In FIG. 5A, the grip portion 12 is rotated leftward, and in FIG. 5B, the handle 11 is tilted rightward. When the operation of FIG. 5A is performed, a second operation amount and a third operation amount are output from the steering device 9, and when the operation of FIG. 5B is performed, a second operation amount and a first operation amount are output from the steering device 9. The control device 8 calculates the thruster azimuths α and β in response to the output of the steering device 9. First, without using the received first operation amount or third operation amount, that is, with the tilt azimuth angle η or the twist angle Z being zero, the thruster azimuths α and β are obtained according to the tilt amount H in the same manner as in the above-described forward movement, and are denoted as α' and β', respectively. Next, values obtained by multiplying the received tilt azimuth angle η and twist angle Z by coefficients A and B (0 ≦ A, B ≦ 1), respectively, are added to α' and β' as shown by the following equations, and the thruster azimuths α and β are calculated. By changing to this thruster azimuth, the hull can be reversely turned in an arbitrary direction by the operator. α = α'+A·η + B·Z β = β'+A·η + B·Z

[0072] FIG. 6 is a diagram for explaining neutral stop in the cruising mode. In the initial stop state or when stopping the hull 7 after movement, the operator positions the handle 11 of the steering device 9 at the center as shown in FIG. 6A. The control device 8 that has received the first operation amount and the second operation amount output from the steering device 9 in this state sets the thruster azimuths of the thrusters 10, 10 on both sides to be inwardly broadside as shown in FIG. 6B, and makes the thruster thrusts on the left and right sides the same. As a result, the thrust vectors of the two azimuth thrusters 10, 10 cancel each other out, and the hull 7 maintains the stop state without accelerating or decelerating.

[0073] FIG. 7 is a diagram for explaining the relationship between the operation of the handle during forward movement in the cruising mode and the thruster thrust of a pair of azimuth thrusters in the ship steering system of the embodiment. In the cruising mode, the increase or decrease of the ship speed is output as a second operation amount according to the operation of the handle 11 of the steering device 9. The control device 8 that receives this output increases or decreases the thruster thrusts of the azimuth thrusters 10 on both sides equally. That is, the thruster thrust on the port side and the thruster thrust on the starboard side in the cruising mode are always the same. When the handle 11 is tilted forward as shown in Fig. 7A, if the azimuth of the port thruster is α, the thruster thrust of the port thruster is Tl, the azimuth of the starboard thruster is β, and the thruster thrust of the starboard thruster is Tr as shown in Fig. 7B, the resultant thrust T of the thruster thrusts of the two azimuth thrusters 10, 10, which is shown by the white arrow acting on the center of gravity G of the hull 7, has the lateral thrusts canceling each other out and only the longitudinal component remains. T = Tlcos α + Trcos β However, since the thrust vectors on both sides are symmetric about the left - right axis, Tl = Tr β = -α holds. The maximum value Tmax of the thruster thrust corresponding to the tilt amount H of the handle 11 is usually the rated rotational speed of the propeller of the azimuth thruster, and the minimum value Tmin of the thrust is the thrust at the propeller rotational speed in the neutral stop state described later. These values can be changed by the parameters of the control device 8 or switches such as knobs attached to the hull 7. This is to prevent excessive vibration from being applied to the hull 7 when the thrust is too large during an emergency stop or the like, so that it can be adjusted according to the operator's intention. The increase amounts of the thruster thrust and the thruster azimuth according to the operation of the handle 11 can be changed by the control device 8. Let the coefficient of the increase amount of the thruster thrust set by the control device 8 be C, and the coefficient of the increase amount of the thruster azimuth be D. Then, Tl = C*H + Tmin cos α = D*H However, C = (Tmax - Tmin) / Hmax holds. As shown in Fig. 6A, it is minimum when the tilt amount H of the handle 11 is at the neutral position and increases in proportion to the increase of the tilt amount H. Also, the resultant thrust T is, T = Tl cos α + Trcos β = Tl cos α + Tl cos (-α) = 2 Tl cos α = 2 (CH+Tmin)DH = 2 CDH 2 - 2TminDH As a result, as shown in Fig. 7C, the combined thrust T is minimized when the tilt amount H of the handle 11 is at the neutral position, and increases in proportion to the square of the tilt amount H. It should be noted that the amount of increase in thruster thrust and thruster azimuth with respect to the operation can be changed by the setting of the control device 8, which is the same in the case of the translational mode described later.

[0074] Fig. 8 is a diagram for explaining the position of the handle 11 and the thrust vector of the thruster in the cruising mode when the above-described coefficients A, C, and D are 1 and B is zero. In Fig. 8, the upper half represents the straight-ahead and left / right turning regions for forward movement, and the lower half represents the straight-ahead and left / right turning regions for backward movement. As described above, the first 、 The thruster azimuth is changed according to the first and third operation amounts, and the thruster thrust is changed according to the second operation amount. Therefore, the thruster thrusts on the same circumference in Fig. 8 are the same. Fig. 8 includes 31 examples including forward movement with a tilt azimuth angle η of 0°, but the tilt azimuth angle η of the handle 11 can be continuously set or adjusted including these. However, when the tilt azimuth angle η enters the vicinity of ±90° from the turning operation region, the operation of the azimuth thruster and the operation of the hull become discontinuous and unnatural. Therefore, when the handle 11 is tilted in the directly lateral direction indicated by "left" or "right" in Fig. 7A, the current (immediately previous) operation is maintained. Note that a certain width is provided in the vicinity of ±90° to recognize the directly lateral direction. Also, the magnitude of the tilt amount H of the handle 11 corresponds to the distance from the center in Fig. 8.

[0075] (IV) Explanation of the translational mode The translational mode will be described with reference to Figs. 9 to 17. FIG. 9 is a diagram illustrating the tilting azimuth angle η of the handle 11 which is the first operation amount of the steering device 9 operated in the translational mode. Although it includes 9 examples including the central figure where the tilting azimuth angle η is 0°, the tilting azimuth angle η of the handle 11 is not limited to these 9 examples and can be continuously set or adjusted including these. Similar to the cruising mode, the steering device 9 outputs the tilting azimuth angle as this first operation amount to the control device 8.

[0076] Also, although not shown in FIG. 9, the steering device 9 outputs the tilting amount H of the handle 11 which is the second operation amount to the control device 8 by adjusting the degree of tilting the handle 11 at a specific tilting azimuth angle. Further, although not shown in FIG. 9, the steering device 9 outputs the torsion angle Z of the handle 11 which is the third operation amount to the control device 8 as shown in FIG. 15 by rotating the grip portion 12.

[0077] FIG. 10 is a diagram for explaining the neutral stop in the translational mode. In the initial stop state or when stopping the hull 7 after movement, the operator positions the handle 11 of the steering device 9 at the central position as shown in FIG. 10A. The control device 8 which has received the first operation amount and the second operation amount output from the steering device 9 in this state sets the thruster azimuths of the thrusters 10, 10 on both sides to be inwardly broadside as shown in FIG. 10B and makes the thruster thrusts on the left and right sides the same. Thereby, the thrust vectors of the two azimuth thrusters 10, 10 cancel each other out and the hull 7 maintains the stop state without accelerating or decelerating.

[0078] FIG. 11 is a diagram for explaining the translational movement (forward / backward movement, lateral movement, diagonal movement) of the hull in the translational mode. Since forward / backward movement and lateral movement can be treated as part of diagonal movement, the relational expression 1 of the thruster azimuths α, β and the thruster thrusts Tr, Tl of the pair of azimuth thrusters 10, 10 when the hull 7 moves diagonally is obtained.

[0079] The lateral component and the forward / backward component of the target thrust (vector) acting on the hull 7 are determined from the tilting azimuth angle η and the tilting amount H of the handle 11 of the steering device 9 shown in FIG. 11A. Fx = H sinη ···························· Equation 1 Fy = H cosη ···························· Equation 2 It is given by

[0080] Also, as shown in Fig. 11B, if the thruster azimuths of the azimuth thrusters 10, 10 on both the left and right sides are α and β respectively, and the magnitudes of the thruster thrusts are Tl and Tr, then since the combined thrust of the X and Y components of the thruster thrusts Tl and Tr becomes Fx and Fy, Fy = Tl cos α + Tr cos β ··················· Equation 3 Fx = Tl sin α + Tr sin β ··················· Equation 4 It can be expressed as

[0081] On the other hand, during translational movement, since the turning components M (the resultant force of the turning components Mr and Ml of the thruster thrusts on both sides) shown in Fig. 11B cancel each other out, Tl sin(α - θ) + Tr sin(β + θ) = 0 ··············· Equation 5 Here, θ represents the angle formed by the straight line L connecting the turning centers of the pair of azimuth thrusters 10, 10 and the center of gravity G of the hull 7 with respect to the center line CL of the hull 7. As described above, when one thruster azimuth is directed towards the center of gravity G and the other thruster azimuth is in the opposite direction to the center of gravity G, the hull moves sideways. Actually, while simultaneously changing the thruster azimuths on both sides of the hull to which the present invention is applied, find the direction in which the hull moves sideways as shown in Fig. 11, and L the angle θ formed by the line connecting each thruster position and the center of gravity G and the hull backward movement direction can be obtained.

[0082] From Equation 3, Tr = (Fy - Tl cos α) / cos β Substituting this into Equation 5 gives Tl sin(α - θ) + ((Fy - Tl cos α) / cos β) * sin(β + θ) = 0 ⇒Tlsin(α - θ) = ((Tlcos α - Fy) / cos β)*sin(β + θ) Right side = ((Tlcos α - Fy) / cos β)*(sinβcos θ + cosβsin θ) = (Tlcos α - Fy)*(tanβcos θ + sin θ) ⇒ sin(α - θ) / (cos α - Fy / Tl) = tan βcos θ + sin θ ··· Equation 6 is obtained.

[0083] From Equation 4,[[]] Tr = (Fx - Tlsin α) / sin β Substituting this into Equation 5,[[]] Tl sin(α - θ) + ((Fx - Tlsin α) / sin β)*sin(β + θ) = 0 ⇒Tl sin(α - θ) = ((Tlsin α - Fx) / sin β)*sin(β + θ) Right side = ((Tlsin α - Fx) / sinβ)*(sin βcos θ + cos βsin θ) = (Tlsin α - Fx)*(cos θ + sin θ / tan β) ⇒ sin(α - θ) / (sinα - Fx / Tl) = cos θ + sin θ / tan β ⇒ sin(α - θ) / (cos θ + sin θ / tan β) = sinα - Fx / Tl ⇒Fx / Tl = sin α - sin(α - θ) / (cos θ + sin θ / tan β) ⇒Tl = Fx / ((sinα - sin(α - θ) / (cos θ + sin θ / tan β)) ··· Equation 7

[0084] Also, from Equation 6,[[]] cos α - Fy / Tl = sin(α - θ) / (tan βcos θ + sin θ) ⇒Fy / Tl = cos α - sin(α - θ) / (tan βcos θ + sin θ) ⇒Tl = Fy / ((cos α - sin(α - θ) / (tanβcos θ + sin θ)) ······ Equation 8 It becomes as follows.

[0085] Eliminating Tl from Equations 7 and 8, Fx / ((sin α - sin(α - θ) / (cos θ + sin θ / tan β)) = Fy / ((cos α - sin(α - θ) / (tanβcos θ + sin θ)) ⇒Fx(cosα - sin(α - θ) / (tan βcos θ + sin θ)) = Fy(sinα - sin(α - θ) / (cos θ + sin θ / tan β)) ⇒Fxcos α - Fxsin(α - θ) / (tan βcos θ + sin θ) = Fysin α - Fysin(α - θ) / (cos θ + sin θ / tan β) ················· Relationship 1

[0086] Furthermore, dividing both sides of Relationship 1 by sin(α - θ), Fxcos α / sin(α - θ) - Fx / (tanβcos θ + sin θ) = Fysin α / sin(α - θ) - Fy / (cosθ + sin θ / tan β) ⇒ (Fxcos α - Fysin α) / sin(α - θ) = Fx / (tan βcos θ + sin θ) - Fy / (cos θ + sin θ / tan β) = Fx / (tan βcos θ + sin θ) - Fytan β / (tanβcos θ + sin θ) =(Fx - Fytan β) / (tanβcos θ + sin θ) Cross - multiplying the numerator and denominator, (Fxcos α - Fysin α)(tan βcos θ + sin θ) = Fxsin(α - θ) - Fytan βsin(α - θ) ⇒ (Fxcos α - Fysin α)tanβcos θ+(Fxcos α - Fysin α)sinθ = Fxsin(α - θ) - Fytan βsin(α - θ) ⇒ ((Fx cos α - Fy sin α)cosθ + Fy sin(α - θ))tan β = Fx sin(α - θ) - (Fx cos α - Fy sin α)sinθ ⇒ tanβ = (Fx sin(α - θ) - (Fx cos α - Fy sin α)sinθ) / ((Fx cos α - Fy sin α)cosθ + Fy sin(α - θ)) It becomes The numerator of the right side = Fx sin α cos θ - Fx cos α sin θ - Fx cos α sin θ + Fy sin α sin θ = Fx sin α cos θ - 2Fx cos α sin θ + Fy sin α sin θ The denominator of the right side = Fx cos α cos θ - Fy sin α cos θ + Fy sin α cos θ - Fy cos α sin θ = Fx cos α cos θ - Fy cos α sin θ Since it becomes tanβ = (Fx sin α cos θ - 2Fx cos α sin θ + Fy sin α sin θ) / ((Fx cos θ - Fy sin θ)cosα) ························ Equation 9 β = tan -1((Fx sin α cos θ - 2Fx cos α sin θ + Fy sin α sin θ) / ((Fx cos θ - Fy sin θ)cosα))······················· Equation 10 is obtained.

[0087] Relational expression 1, Equation 9 and Equation 10 derived from this show the relationship between the tilting azimuth angle η and tilting amount H of the handle 11 output from the control device 9 by the operation of the operator and the thruster azimuths α and β when the lateral component Fx (refer to the above Equation 1) and the fore-and-aft component Fy (refer to the above Equation 2) of the thrust of the hull 7 are given.

[0088] Also, from Equation 3 and Equation 4, Tl = (Fy - Tr cos β) / cosα Tl = (Fx - Trsinβ) / sinα Canceling out Tl, (Fy - Trcosβ) / cosα = (Fx - Trsinβ) / sinα Cross - multiplying the numerator and denominator, (Fx - Trsinβ)cosα = (Fy - Trcosβ)sinα ⇒ Fxcosα - Trsinβcosα = Fysinα - Trcosβsinα ⇒ Trsinαcosβ - Trcosαsinβ = Fysinα - Fxcosα Therefore, the starboard thruster thrust Tr is, Tr = (Fysinα - Fxcosα) / sin(α - β) ··········· Equation 11 given by this.

[0089] Similarly, from Equation 3 and Equation 4, Tr = (Fy - Tlcosα) / cosβ Tr = (Fx - Tlsinα) / sinβ Canceling out Tr, (Fy - Tlcosα) / cosβ = (Fx - Tlsinα) / sinβ Cross - multiplying the numerator and denominator, (Fy - Tlcosα)sinβ = (Fx - Tlsinα)cosβ ⇒ Fysinβ - Tlcosαsinβ = Fxcosβ - Tlsinαcosβ ⇒ Tlsinαcosβ - Tlcosαsinβ = Fxcosβ - Fysinβ The port thruster thrust Tl is, Tl = (Fxcosβ - Fysinβ) / sin(α - β) ··········· Equation 12 given by this.

[0090] According to the above logic, since θ is known in the hull 7, if the tilting azimuth angle η and the tilting amount H are given by operating the steering device 9, the control device 8 can calculate the relationship between the thruster azimuths α, β of the pair of azimuth thrusters 10, 10 and the thruster thrusts Tr, Tl. Also, substituting Equation 1 and Equation 2 into Equation 9, tan β=( Hsin ηsin αcos θ-2Hsin ηcos αsin θ+Hcos ηsin αsin θ) / {(Hsin ηcos θ-Hcos ηsin θ)cos α} The H in the denominator and numerator is canceled out, tan β=(sin ηsin αcos θ-2sin ηcos αsin θ+cos ηsin αsin θ) / {(sin ηcos θ-cosηsin θ)cosα} This means that the relationship between α and β does not depend on the tilting amount H. Similarly, Equations 11 and 12 are Tr=H(cos ηsin α-sin ηcos α) / sin(α-β) Tl=H(sin ηcos β-cos ηsin β) / sin(α-β) That is, the thruster thrusts Tr and Tl are proportional to the tilting amount H.

[0091] Figure 12 is a graph of the relational expression 1 (or Equation 9 or Equation 10) showing the relationship between the lateral component Fx and the fore-and-aft component Fy of the target thrust given by the tilting azimuth angle η which is the first operation amount output by the steering device 9 and the tilting amount H which is the second operation amount when the hull 7 moves, and the thruster azimuths α and β of the pair of azimuth thrusters 10, 10. When graphing, the angle θ which is a fixed value determined from the ship's structure and equipment is taken as 10 degrees as an example, the tilting amount H which is the second operation amount is taken as 1, and the tilting azimuth angle η which is the first operation amount is taken as 0°, 5°, 15°, 45°, 90°, 135° for graphs 1 to 6. Further, the thruster azimuths α and β given by this graph and the thruster thrusts Tl and Tr of the pair of azimuth thrusters 10, 10 calculated from the above Equations 11 and 12 are superimposed and displayed on the graph.

[0092] FIG. 13 is a graph similar to FIG. 12, where the tilting azimuth angle η, which is the first operation amount, is set to 165°, 175°, 180°, -135°, -90°, and -45° for graphs 7 to 12. Other conditions are the same as those in FIG. 11.

[0093] From Relational Expression 1, the above-described Expressions 11 and 12, and the graphs of FIGS. 12 and 13 visualizing these, if the angle θ indicating the arrangement of the pair of azimuth thrusters 10, 10 which are fixed values of the hull 7, the tilt amount H and the tilt azimuth angle η output when the steering device 9 is operated are given, it can be understood that there are a number of combinations of the thruster azimuths α, β and the thruster thrusts Tl, Tr of the pair of azimuth thrusters 10, 10 that can apply a desired target thrust to the hull 7. For example, the upper left graph in FIG. 12 shows the case where the tilt azimuth angle η = 0°, and the hull is translated in the forward straight-ahead direction. The thruster azimuth α is represented by an upward-right straight line, and the thruster azimuth β is represented by a downward-right straight line. The thruster thrusts Tl, Tr corresponding to these thruster azimuths are represented by broken lines, but at the tilt azimuth angle η = 0°, both coincide and overlap. When the thruster azimuth α is changed from -180° to 180° (horizontal axis), the corresponding thruster azimuth β changes from 180° to -180° (right vertical axis). This means that the left and right thruster azimuths are in symmetric positions. On the graph, the thruster azimuth α is continuously shown from -180° to 180°, but in the vicinity of -90° and 90° of the thruster azimuth α, the magnitudes of the thruster thrusts Tl, Tr (left vertical axis) increase significantly, resulting in inefficiency. Also, in the regions where the thruster azimuth α is α < -90° and 90 < α, the thruster thrusts Tl, Tr are negative. This is a state where the propeller is reversed after setting the thruster azimuth in the reverse direction, and in the case of an azimuth thruster driven by an engine, it is an unreasonable combination. Therefore, in reality, within the range where the thruster azimuth α is approximately from -80° to 80°, a combination of the thruster azimuths α, β and the thruster thrusts Tl, Tr can be selected. Regarding the remaining graphs in FIG. 12, the explanation is omitted here, but the thruster thrusts Tl, Tr are shown by separate broken lines without overlapping. From the above, it can be understood that there are a number of combinations of the thruster azimuths α, β and the thruster thrusts Tl, Tr of the pair of azimuth thrusters 10, 10 that can apply a desired target thrust to the hull 7 within a practically and reasonably selectable range.The control device 8 selects, from among these combinations, the combination of the thruster azimuths α, β and the thruster thrusts Tl, Tr that is optimal for the pair of azimuth thrusters 10, 10 to apply the target thrust to the hull 7 by the first to fourth control methods described below.

[0094] In the translational mode, when the steering wheel 11 is moved to change the course / speed of the hull 7, each azimuth thruster 10, 10 will move from the current state (α1, β1, Tl1, Tr1) to the next state (α2, β2, Tl2, Tr2). In that case, it is considered that the more smoothly and efficiently the ship is maneuvered, the smaller the changes in the thruster azimuths α, β and the thruster thrusts Tl, Tr. That is, it is advisable to select α2, β2, Tl2, Tr2 such that the values of |α2 - α1|, |β2 - β1|, |Tl2 - Tl1|, and |Tr2 - Tr1| are minimized.

[0095] 1) First control method In the ship steering system 1 of the present embodiment, in the stopped state where the steering wheel 11 is not tilted, the pair of azimuth thrusters 10, 10 is in the "neutral stop" state shown in Fig. 10. Therefore, this state is given to the control device 8 as the initial values (α1 = 90°, β1 = -90°, Tl1 = Tr1 = Tmin). Then, the control device 8 calculates the relationship between the thruster azimuths α2, β2 and the thruster thrusts Tl2, Tr2 from the tilt azimuth angle η and the tilt amount H when the steering wheel 11 is first moved, using relational expression 1 and the like. From among the obtained numerous combinations, the control device 8 selects the combination of α2, β2, Tl2, Tr2 such that the larger of the values of |α2 - α1| and |β2 - β1| is minimized. By repeatedly executing this operation each time the steering wheel 11 is moved thereafter, the control device 8 can perform efficient and smooth ship maneuvering.

[0096] However, among the combinations of α2, β2, Tl2, and Tr2, when Tl2 and Tr2 are zero or negative values, or when the combination includes extremely large values, etc., it cannot be said to be a realistic choice. Therefore, a realistic maximum value, that is, a limit value, is set based on the thruster thrust that the azimuth thruster 10 can generate, namely the rated value of the propeller rotation, the rated output of the engine, etc., and the combination is selected within that range. Specifically, the control device 8 is assumed to select a combination such that the thruster thrust is equal to or greater than zero and equal to or less than the maximum thrust of the azimuth thruster 10. The same applies to the second and third control methods described later.

[0097] FIG. 14 is a diagram for explaining a method by which the control device 8 calculates and selects a combination of thruster azimuth and thruster thrust of a pair of azimuth thrusters 10, 10 that generate a target thrust in the translational mode of the ship control system 1 according to the embodiment. FIG. 14A is a diagram in which, in the graph 2 shown in FIG. 12, when the control device 8 selects an appropriate combination of thruster azimuth and thruster thrust of a pair of azimuth thrusters 10, 10, a selectable region where such a combination exists is displayed in the graph with a hatched frame on the condition that the combination is selected such that the thruster thrust is equal to or greater than zero and equal to or less than the maximum thrust of the azimuth thruster 10.

[0098] Further, according to the first control method, in order to select a combination such that the larger of the values of the thruster azimuth differences |α2 - α1| and |β2 - β1| before and after the operation of the steering device 9 becomes the minimum, the time required for the rotation of the azimuth thruster 10 is the shortest. However, when selecting the thruster azimuth, it may be necessary to consider other factors excluding the time required for the thruster to rotate. For example, a combination in which a pair of thrusters face each other inward and the water flows ejected from each other collide with each other is preferably avoided from the viewpoints of mechanical influence and efficiency. By selecting a combination in which the thruster azimuth differences |α2 - α1| and |β2 - β1| before and after the operation of the steering device 9 are smaller within the selectable range excluding such cases, it is possible to suppress failures and fuel consumption of the azimuth thruster 10.

[0099] 2) Second control method α2, β2, Tl2, and Tr2 selected by the first control method are a combination that minimizes the change in thruster orientation, but not a combination that minimizes the change in thruster thrust. Therefore, even if the change in thruster orientation is minimized, it takes time for the change in thruster thrust, and a lot of time and power may be required to change the course or speed of the hull. Thus, in the second control method, the determination is made including not only the current state and the thruster orientation differences |α2 - α1| and |β2 - β1| after the operation of the control device, but also the thruster thrust differences |Tl2 - Tl1| and |Tr2 - Tr1| after the operation of the control device. That is, by selecting a thruster orientation combination such that the largest among |α2 - α1|, |β2 - β1|, |Tl2 - Tl1|, and |Tr2 - Tr1| becomes the smallest, smooth and efficient control can be performed.

[0100] Note that since the units of thruster orientation and thruster thrust are different, it is not possible to determine which of the differences (change amounts) before and after the operation of the four values is the largest by simple comparison. Therefore, the differences before and after the operation of each value are expressed as a ratio (percentage) with respect to the maximum value of each value, and a thruster orientation combination is selected such that the value expressed as the ratio (percentage) becomes the smallest. That is, the minimum value of the thruster thrust is set to 0% and the maximum value is set to 100%, and the amount by which the thruster thrust Tl and the thruster thrust Tr should be changed is calculated in %. For the thruster orientation, which is in the changeable range of 0 to 180°, the angle by which the thruster orientation α or the thruster orientation β should be changed is calculated in % with respect to 180°. Then, the change amounts of the thruster thrust and the thruster orientation are compared in %, and a thruster orientation combination is selected such that the maximum value becomes the smallest.

[0101] 3) The third control method The combination of α and β selected by the second control method is the combination that minimizes the changes in thruster orientation and thruster thrust. However, the time required to reach the thruster orientation and thruster thrust (α2, β2, Tl2, Tr2) after the operation from the current state depends on the acceleration and deceleration capabilities of the propeller rotation speed and the nozzle turning ability. Therefore, the combination of α and β selected by the second control method is not the combination with the shortest arrival time. Thus, in the third control method, from the current state of the control device, among the times required to reach the thruster orientation and thruster thrust after the operation, that is, the estimated arrival time required to reach the target, the combination of thruster orientations is selected such that the largest one becomes the smallest, and smooth operation is performed. These estimated times can be obtained from design data, test data, control parameters, etc. of the engine, azimuth thruster, propeller, etc. For example, assume that combination 1 and combination 2 are selectable for the combination of α and β. If the times required to reach the thruster orientation and thruster thrust (α2, β2, Tl2, Tr2) after the operation are 30 seconds, 45 seconds, 60 seconds, and 20 seconds for combination 1, then the maximum value of the estimated arrival time is 60 seconds for thruster thrust Tl. On the other hand, if they are 20 seconds, 45 seconds, 30 seconds, and 20 seconds for combination 2, then the maximum value is 45 seconds for thruster orientation β. Comparing the maximum values of 60 seconds and 45 seconds, the smaller combination 2 is selected. In the example, two selectable combinations were used, but when the number of combinations increases, the combination including the minimum value is selected.

[0102] 4) Fourth control method The α2, β2, Tl2, and Tr2 selected by the first control method are a combination that minimizes changes in thruster orientation. However, when the hull 7 sails for a period exceeding a predetermined time with the target thrust generated by this combination, considering fuel consumption, it is considered preferable to select a combination that minimizes the sum of the thruster thrusts Tl2 and Tr2. Therefore, the control device 8 of the embodiment performs control by the first control method immediately after the position of the steering wheel 11 is changed. When there is no change in the position of the steering wheel 11 for a period exceeding a predetermined time, the control device 8 can also adopt a fourth control method in which the combination gradually shifts to a combination of thruster orientations α2 and β2 and thruster thrusts Tl2 and Tr2 that minimizes the sum of the thruster thrusts Tl2 and Tr2.

[0103] Figure 14B is a partially enlarged view of a part of the selectable region in Figure 14A, showing a selection point A indicating the values of the thruster thrusts of the pair of azimuth thrusters 10, 10 initially selected, and a selection point B where the sum of the thruster thrusts of the pair of azimuth thrusters 10, 10 is smaller. According to the first control method, the control device 8 selects the selection point A in a combination such that the larger of the thruster orientation differences |α2 - α1| and |β2 - β1| before and after the operation of the steering device 9 is minimized. However, if there is no change in the position of the steering wheel 11 for a predetermined time thereafter, the control device 8 performs control to shift to the selection point B where the sum of the thruster thrusts of the pair of azimuth thrusters 10, 10 is smaller and sail. As a result, the fuel consumption can be suppressed lower than when only the first control method is performed.

[0104] 5) Fifth control method In the second control method, the combination of thruster orientations is selected based on the values of the thruster orientation differences |α2 - α1| and |β2 - β1| and the thruster thrust differences |Tl2 - Tl1| and |Tr2 - Tr1| between the current state and the state after the operation of the steering device. However, in the fifth control method, based on the combination of thruster orientations and thruster thrusts that are symmetric about the left and right when moving forward and backward in the cruising mode described above, the combination of thruster orientations α, β, and thruster thrusts Tl, Tr is selected. When the tilting azimuth angle η which is the first operation amount and the tilting amount H which is the second operation amount are output from the control device 9, as described with reference to FIG. 2, the same control as when the hull performs straight-ahead movement in the cruising mode is performed. With the thruster azimuths α = 90° and β = -90° as initial values, the forward components of the thruster azimuth and the thruster thrust are increased or decreased according to the increase or decrease of the tilting amount H, thereby calculating the left-right symmetric reference values of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters. That is, let the thruster azimuths obtained from this tilting amount H be α0 and β0 respectively as reference values, and let the thruster thrusts be Tl0 and Tr0 respectively as reference values. Next, calculate the value of the thruster azimuth difference |α2 - α0| which is the difference between the reference value α0 and the thruster azimuth α2 after operating the control device, the value of the thruster azimuth difference |β2 - β0| which is the difference between the reference value β0 and the thruster azimuth β2 after operating the control device, the value of the thruster thrust difference |Tl2 - Tl0| which is the difference between the reference value Tl0 and the thruster thrust Tl2 after operating the control device, and the value of the thruster thrust difference |Tr2 - Tr0| which is the difference between the reference value Tr0 and the thruster thrust Tr2 after operating the control device. Then, select a combination of thruster azimuths α and β such that the largest one among these is minimized as a ratio. In this case, the selection of the combination of thruster azimuths α and β is independent of the progress of ship operation, reproducibility occurs in the selection, and the operation of the ship control system becomes stable.

[0105] By substituting α and β selected by the above control method into Equations 11 and 12, Tl and Tr are calculated, and by changing to the combination of the thruster azimuth and the thruster thrust, a target thrust can be generated on the hull 7 to move it in an arbitrary direction. From the selected combination of the thruster azimuth α on the port side and the thruster azimuth β on the starboard side, the thruster thrust Tl on the port side and the thruster thrust Tr on the starboard side are calculated, and by controlling four types of operations of the pair of azimuth thrusters, the change amounts of the thruster azimuth and the thruster thrust can be minimized, and rapid and smooth ship operation can be realized. Here, in the calculation of the above-mentioned α, β, Tl, and Tr in the translational mode, the target thrust to be generated on the hull is made constant in all directions of 360°. That is, when the handle 11 is tilted to the maximum position, regardless of the tilt azimuth angle η being in any azimuth from -180° to 180°, the tilt amount H of the handle is equal at the maximum value (=1), and thereby the target thrust to be generated on the hull also becomes equal in all directions of 360°. In the case of the ship in the embodiment, in the fore-and-aft direction, it is easy to generate thrust on the hull and easy to gain speed, while in the transverse direction, the proportion of the thrust partially canceling each other between the left and right azimuth thrusters is large, making it difficult to generate thrust on the hull and also difficult to gain speed. Since there are upper limits to the thrusts Tl and Tr that the left and right azimuth thrusters can generate, in the control of the above-mentioned translational mode, the maximum value of the target thrust to be generated on the hull is adjusted to a value that can be generated even in the inefficient transverse direction. Since the relationship between the tilt amount H of the handle and the target thrust to be generated on the hull is the same for any direction of 360°, in the transverse direction, the thrusts Tl and Tr generated by the left and right azimuth thrusters reach the upper limit, while in the forward and backward directions, there is a margin in the thrusts Tl and Tr that can be generated. Therefore, as a selective method, the tilt amount H of the handle 11 output from the steering device 9 is converted by the control device 8 into a corrected tilt amount H' according to the following formula according to the tilt azimuth angle η of the handle. H’ = f(η) × H Here, f(η) is an approximate formula for the thrust that can be generated according to the tilt azimuth angle η, and is obtained by approximation through numerical calculation or experiment. The values for directions closer to forward and backward are larger, and the values for the transverse direction are smaller. For example, in an example of the calculation in the case of θ = 10° in the embodiment, when the value of f(η) in the transverse direction (η = 90°) is set to 1, the value of f(η) in the forward direction (η = 0°) is approximately 5. Thereby, also in the translational mode, the thruster thrusts Tl and Tr can be generated near the upper limit at the tilt azimuth angle η near the forward or backward direction, enabling navigation up to near the maximum speed. Also, there is no need to switch from the translational mode to the cruising mode, and a seamless steering feeling can be obtained.

[0106] (V) Parallel translation mode and azimuth correction When navigating in the parallel translation mode, the hull azimuth may change due to disturbances such as hydrodynamic forces and wind, and it may not be possible to move the hull arbitrarily. Therefore, a control method for azimuth correction of the hull 7 in the parallel translation mode will be described with reference to FIGS. 15 and 11. As a control method for azimuth correction, manual correction by operating the operator's handle 11 (hereinafter referred to as manual feedback control) is used. Specifically, as shown by the arrow in FIG. 15, an operation is performed to rotate the grip portion 12 of the handle 11 of the steering device 9 in a desired direction. In the illustrated example, it is rotated to the left. By this operation, a third operation amount indicating the twist angle Z of the handle 11 is output from the steering device 9, and the control device 8 that has received this controls the azimuth thruster 10 as described below to generate a turning component M on the hull 7 and return the hull azimuth in the direction in which the handle 11 is rotated. to The control device 8 that has received this controls the azimuth thruster 10 as described below to generate a turning component M on the hull 7 and return the hull azimuth in the direction in which the handle 11 is rotated.

[0107] Tlsin(α - θ) + Trsin(β + θ) = 0 ················ Equation 5 In the above Equation 5 described with reference to FIG. 11, it is conditioned that two turning components M (Ml and Mr in FIG. 11B) cancel each other out in order to translate the hull 7, and the right side is zero. However, when performing azimuth correction of the hull 7, a turning component M is required, so the right side of Equation 5 is not zero but becomes a turning component M of a predetermined value. That is, Tlsin(α - θ) + Trsin(β + θ) = M ················ Equation 13 becomes.

[0108] As shown in FIG. 11B, when the hull 7 is moving in parallel translation, the two turning components cancel each other out and maintain equilibrium. However, if the azimuth or thrust of either the port or starboard azimuth thruster 10 is changed, the equilibrium is broken and a turning component that rotates the hull 7 is generated. The magnitude of the turning component in that case is Port: Tlsin(α - θ) Starboard: Trsin(β + θ) However, in order to generate a yaw component in the hull 7, it is preferable to select and change any one of the four items of the current thruster azimuth and thruster thrust Tl, Tr, α, and β of the pair of azimuth thrusters 10, 10, which can most effectively change the above yaw component when its value is changed.

[0109] Therefore, the control device 8 of the ship maneuvering system 1 can be configured to use means for selecting the thruster azimuths α and β and the thruster thrusts Tl and Tr on the condition that the yaw component M is taken into account as a means for correcting the hull azimuth in the translational mode.

[0110] When the yaw component M is taken into account, as described above, the right side of Equation 5 is not zero, and becomes a yaw component M of a predetermined value as in Equation 13. From Equation 3, Tr = (Fy - Tlcos α) / cos β Substituting into Equation 13, Tlsin(α - θ) + {(Fy - Tlcos α) / cos β} * sin(β + θ) = M ⇒ Tlsin(α - θ) = {(Tlcos α - Fy) / cos β} * sin(β + θ) + M = {(Tlcos α - Fy) / cos β} * (sinβcos θ + cos βsin θ) + M = (Tlcos α - Fy) * (tanβcos θ + sin θ) + M = Tlcos α(tanβcos θ + sin θ) - Fy(tanβcos θ + sin θ) + M ⇒ Tl{sin(α - θ) - cosα(tanβcos θ + sin θ)} = -Fy(tanβcos θ + sin θ) + M ⇒ Tl = {-Fy(tanβcos θ + sin θ) + M} / {sin(α - θ) - cos α(tanβcos θ + sin θ)} ··· Equation 14 From Equation 4, Tr = (Fx - Tlsin α) / sin β Substituting into Equation 13, Tlsin(α - θ) + {(Fx - Tlsin α) / sin β} * sin(β + θ) = M ⇒ Tlsin(α - θ) = {(Tlsin α - Fx) / sin β} * sin(β + θ) + M = {(Tlsin α - Fx) / sin β} * (sinβcos θ + cosβsin θ) + M = (Tlsin α - Fx) * (cosθ + sinθ / tanβ) + M = Tlsin α(cosθ + sinθ / tanβ) - Fx(cosθ + sinθ / tanβ) + M ⇒ Tl{sin(α - θ) - sinα(cosθ + sinθ / tanβ)} = -Fx(cosθ + sinθ / tan β) + M ⇒ Tl = {-Fx(cosθ + sin θ / tanβ) + M} / {sin(α - θ) - sinα(cosθ + sin θ / tanβ)} ··· Equation 15 From Equations 14 and 15, by eliminating Tl, {-Fy(tanβcos θ + sin θ) + M} / {sin(α - θ) - cosα(tanβcos θ + sin θ)} = {-Fx(cosθ + sin θ / tanβ) + M} / {sin(α - θ) - sinα(cosθ + sin θ / tanβ)} ··· Relationship 2 From the above, Relationship 2 considering the turning component M is obtained. As a control method for selecting the thruster orientation and thruster thrust from Relationship 2, the above-described second control method is used. The control device 8 determines the turning component and can obtain α, β, Tl, and Tr necessary to translate the hull while suppressing the turning component generated by disturbances such as fluid forces and wind by using Relationship 2 and the second control method. Also, when Relationship 2 is transformed with the turning component set to zero, it coincides with Relationship 1. Also, as control methods for selecting the thruster orientation and thruster thrust, the first and third control methods are also applicable.

[0111] According to the above-described means, while the hull is being translated, the hull orientation can be corrected. However, when the external disturbances such as the hydrodynamic forces and wind acting on the hull 7 are large, the required yawing component will also become correspondingly large. If the yawing component is large, the thruster thrust required to achieve both translation and hull correction may exceed the maximum thrust of the azimuth thruster. As a countermeasure 1, the target thrust of the hull determined according to the first operation amount and the second operation amount is decreased, and the thrust distributed to the yawing component is increased. By calculating the combination of thruster azimuth and thruster thrust from relational expression 2 using the decreased target thrust, a combination in which the thruster thrust is below the maximum thrust can be calculated.

[0112] The above-described countermeasure 1 is a method of distributing a part of the thrust that should originally be spent on translation to the yawing component while maintaining the translation direction. However, even if the target thrust is reduced close to zero, the state shown in FIG. 16A is the limit, and there may be a case where the required yawing component cannot be sufficiently generated. Therefore, a countermeasure 2 that temporarily sacrifices translation is taken. For example, as shown in FIG. 16B, the azimuth α of the thruster on the port side is changed to 90° + θ, and the azimuth β of the thruster on the starboard side is changed to -90° - θ, that is, to an angle perpendicular to θ at which the yawing component becomes larger. Next, when correcting the hull orientation to the left, the thruster thrust on the port side is output according to the magnitude of the yawing component, and when correcting the hull orientation to the right, the thruster thrust on the starboard side is output according to the magnitude of the yawing component, and the thruster thrust on the side that does not contribute to the hull correction is set to zero. Since the thrust of one thruster is all used for the yawing component, the hull orientation can be corrected even if large external disturbances such as hydrodynamic forces and wind act on the hull 7. However, when countermeasure 2 is performed, the translation instructed by the operator stops. Therefore, if the thruster thrust calculated by countermeasure 1 is below the maximum thrust, immediately return to countermeasure 1. In addition, if the correction is excessive, since the other azimuth is also set to an angle at which the yawing component in the opposite direction becomes maximum, it is easy to correct by driving this.

[0113] Note that, like the thruster schematically shown in FIG. 1, the propeller 3 is provided inside a cylindrical nozzle (referred to as a " Kort nozzle") whose cross section parallel to the water flow direction is airfoil-shaped, and there are cases where the Kort nozzle generates lift by the water flow to improve the propeller efficiency. In the above countermeasure 2, only one thruster was driven in accordance with the orientation of the hull correction, and the thrust of the other thruster was set to zero. In this way, even when the thrust is zero and the thruster is not generating thrust, if the thruster has the above-described Kort nozzle, the hull may obtain propulsion force from the water flow just by moving and generate thrust on the hull. That is, it is conceivable that the Kort nozzle of the thruster acts like a rudder, and as a result, the hull moves unexpectedly. Therefore, in this countermeasure 2, as one of the purposes of preventing this, instead of leaving the angle of the thruster with zero thrust in an arbitrary state, it is changed to the angle at which the turning component becomes maximum to prevent unexpected movement of the hull.

[0114] (VI) Advanced Method for Azimuth Correction The above-described correction method is a method of correction by operating the steering wheel 11 so as to cancel the change in the hull azimuth visually confirmed by the operator, and is a manual feedback control via the operator. In this control, since the sensing of the current direction and the correction control operation are performed manually, there may be a lack of accuracy and speed. Therefore, as another method, there is azimuth angle control. The hull azimuth information is periodically acquired from the navigation instruments installed on the hull via communication or the like, the hull azimuth at the time when the third operation amount becomes zero is set as the target hull azimuth, the azimuth angle deviation between the actual hull azimuth and the target hull azimuth is calculated, the value of the turning component M is determined so that the azimuth angle deviation becomes zero, and azimuth angle control is performed. Further, the target hull azimuth may be the hull azimuth at the time of switching when switching the steering mode from the cruising mode to the parallel movement mode. Furthermore, the azimuth control may be used in combination with manual feedback control. When combining, the priority of correction is higher for manual feedback control. When a third operation amount is input by the operator, a turning component M for achieving it is generated to correct the hull azimuth. When the third operation amount is not input, the turning component M is generated by azimuth control. Manual correction by manual feedback control can be combined in the same way as other methods described later. By combining the manual correction and automatic correction by the operator, the hull azimuth can be corrected as intended by the operator, and the time until the hull azimuth is corrected can be shortened.

[0115] Even if the thruster azimuth and thruster thrust are controlled to make the azimuth deviation zero, the correction operation may be slow and it may take time to converge. Therefore, as another method, PD control may be used. The azimuth deviation is calculated with the hull azimuth when the third operation amount becomes zero as the target hull azimuth, and the turning component M is set to the value obtained by adding the value obtained by multiplying the azimuth deviation by a coefficient and the value obtained by multiplying the time derivative of the azimuth deviation by a coefficient. This is PD control that takes into account the changing component of the azimuth. Compared with simple azimuth control (P control), by also controlling the turning angular velocity (D control), which is the differential component of the hull azimuth, the change in azimuth can be predicted and rapid azimuth correction can be performed.

[0116] Although azimuth PD control is a method of predicting the change in azimuth because the turning component M increases as the azimuth deviation increases, since the turning component M is not determined to make the azimuth deviation zero, the hull azimuth may not easily reach the target value. Therefore, as another control method, cascade control combining azimuth control and angular velocity feedback with the value obtained by multiplying the azimuth deviation by a coefficient as the target angular velocity may be used. In cascade control, first, the azimuth deviation is calculated with the hull azimuth when the third operation amount becomes zero as the target hull azimuth. The turning angular velocity measured by a measuring instrument is subtracted from the value obtained by multiplying this azimuth deviation by a coefficient. Then, the value obtained by multiplying the difference obtained by this subtraction by a coefficient is defined as the turning component M. That is, the larger the azimuth deviation and the turning angular velocity, the larger the turning component M, and the smaller the azimuth deviation and the turning angular velocity, the smaller the turning component M. Multiplying the deviation by a coefficient in the control is to adjust for the different effects of the azimuth deviation on the turning angular velocity by the hull. By manually correcting with the operator and performing cascade control on the hull azimuth and the turning angular velocity, it is possible to reduce the turning angular velocity while approaching the hull azimuth to the target hull azimuth.

[0117] In the cascade control described above, the turning angular velocity is measured by a measuring instrument and used. However, when the navigation instruments installed on the hull have a function to detect the hull azimuth but do not have a turning angular velocity detection function, it is also possible to time-differentiate the hull azimuth information and use the turning angular velocity information. By using this method, it is possible to perform azimuth PD control or cascade control without obtaining the turning angular velocity information from the instruments.

[0118] As another method, it is possible to use turning angular velocity feedback control that obtains the turning angular velocity information or the turning angular acceleration of the hull from the instruments installed on the hull and determines the value of the turning component M so as to make this zero.

[0119] Also, as another method, when the thruster azimuth is close to 90° + θ or -90° - θ, which are the directions of the two turning components Ml and Mr shown in FIG. 11B, the closer thruster thrust Tl or Tr may be changed, and when it is far, the thruster azimuth α or β may be changed. This determination of "far" or "close" is made by adopting a threshold value obtained empirically or experimentally in advance, and it can be changed by the control device 8.

[0120] When changing the thruster thrust Tl or Tr, the maximum value of the thruster thrust is set to 100%, the amount to be changed for the thruster thrust Tl and Tr is calculated in %, and the thruster thrust with the smaller change amount is adopted. When changing the thruster azimuth α or the thruster azimuth β, the angle to be changed for the thruster azimuth α or the thruster azimuth β is calculated as a % with respect to 180°, which is the possible change range of the thruster azimuth, and the thruster azimuth with the smaller change amount is adopted. Alternatively, both the thruster thrust and the thruster azimuth with the smaller change amount selected as described above may be changed. By changing both the thruster thrust and the thruster azimuth in this way, compared with the case of changing only the thruster azimuth, the correction of the azimuth of the hull 7 can be made more efficient and the correction can be performed more quickly.

[0121] Furthermore, as another method, manual feedback control, azimuth control, and yaw rate feedback control may be combined. The priority order is manual feedback control, yaw angular acceleration feedback control, and azimuth control, and the priority decreases in this order. Normally, the response component M is determined using yaw angular acceleration feedback control, and when there is an output of the third operation amount, manual feedback control is used preferentially. When the deviation of the method with the higher priority converges, the correction method with the lower priority becomes effective. By combining the correction methods in this way, the change in the hull azimuth due to disturbances such as fluid forces and wind can be minimized, and the hull can be translated while maintaining the desired traveling direction with a minimum amount of steering operation.

[0122] (VII) Other operations When approaching and stopping the hull with respect to an object such as in berthing operations, a ship handling technique called "nudging" may be required to decelerate. For example, when berthing at a quay wall on the right side of the hull 7, after aligning the advancing direction of the hull 7 parallel to the quay wall side, it is translated parallel to the right towards the quay wall. When approaching the quay wall, nudging is applied to turn back to the left, and if it is turned back too much, it is turned back to the right again. Such ship handling operations are assumed. Graph 13 in Fig. 17 is when the tilt azimuth angle η = -90 degrees, that is, when advancing in the true right direction, and graph 14 is when the tilt azimuth angle η = +90 degrees, that is, when advancing in the true left direction. When applying nudging, rather than moving back and forth between the lightly shaded areas in both figures, moving back and forth between the darker shaded areas results in less change in the thruster azimuth. The same applies when comparing graph 15 (tilt azimuth angle η = -140 degrees) and graph 16 (tilt azimuth angle η = +40 degrees) in Fig. 17. Therefore, when intending ship handling operations involving nudging such as berthing, it is desirable to select a range where the thruster azimuth α is as close to 90 degrees as possible by operating an input such as a separately provided "berthing" switch. Conversely, in offshore operations etc. where there is little need for nudging or when making a long parallel translation, by operating an input such as a separately provided "offshore" switch, it is fuel-efficient to select an area (near the lightly shaded area) where the sum of the thruster thrusts Tl and Tr is minimized.

[0123] (VIII) Remote control In the ship handling system 1 of the embodiment described above, if a remote control device 15 is used instead of the manual control device 9, the hull 7 can be remotely controlled from a control base provided outside the hull 7.

[0124] Fig. 18 is a diagram for explaining remote ship handling in the parallel translation mode of the ship handling system of the embodiment. As shown in Fig. 18A, assume that the hull 7 described above is, for example, tag boats 21 and 22. The tag boats 21 and 22 are mainly used to guide a large ship 100 such as a tanker that cannot move finely in a narrow place by pushing it at the bow, pulling it with a rope, etc., and to safely leave and approach the shore. In Fig. 18A, a receiver of a remote control device is placed on the tag boats 21 and 22, and a transmitter of the remote control device for the tag boats 21 and 22 is placed on the large ship 100. Fig. 18B is a schematic plan view of the control devices 9a and 9b provided in the transmitter of the remote control device, and the tag boat 21 can be controlled by the control device 9a, and the tag boat 22 can be controlled by the control device 9b. When it is desired to move the large ship 100 directly below in Fig. 18A, a navigator or pilot on board the large ship 100 (who conventionally instructs the operation of the tag boat orally) pulls the handles 11 and 11 of the control devices 9a and 9b provided in the transmitter of the remote control device forward, thereby moving the left and right tag boats 21 and 22 forward and moving the large ship directly below. Also, although the operation of the hull 7 with respect to the handle operation is reversed from the description with reference to Figs. 1 to 17, it is possible to change the operation direction of the hull 7 with respect to the tilt azimuth angle η of the handle 11 by inputting -1 to the coefficient A that can be set by the control device 8. Also, as shown in Fig. 18C, one control device 9 as shown may be provided on the large ship 100, and a navigator of the large ship 100 may operate this control device 9 to control the tag boats 21 and 22 and the large ship 100. By the operation by the control device 9, the control device mounted on the large ship 100 calculates the target thrust to be applied to the large ship, and distributes this target thrust to the thrusts of the two tag boats 21 and 22 and the large ship 100. For example, when the handle 11 is tilted diagonally downward to the right, the target thrust to be generated downward is distributed by the tag boats 21 and 22, and the target thrust to the right is generated by moving the large ship forward, and the large ship can be moved with a steering feeling as if directly controlling the large ship 100 itself.

Explanation of Signs

[0125] 1…Ship steering system 2…Propeller shaft 3…Propeller 4…Motor 5…Engine 6…Output shaft 7…Hull 8…Control device 9…Steering device 10…Azimuth thruster (thruster) 11…Handle of the steering device 12…Grip part of the steering device 15…Remote control device 16…Receiver of the remote control device 17…Transmitter of the remote control device α, β…Thruster azimuth of the azimuth thruster Tl, Tr…Thruster thrust of the azimuth thruster η…Tilt azimuth angle of the handle of the steering device (first operation amount) H…Tilt amount of the handle of the steering device (second operation amount) Z…Twist angle of the handle of the steering device (third operation amount) G…Center of gravity of the hull CL…Center line of the hull

Claims

1. A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a control device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, a control device that controls the azimuth thruster by operating the control device, A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel, In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the control device, The thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters, and the combination of the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β are calculated and selected so as to obtain the target thrust, In the parallel movement mode, the control device The combination of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull, The lateral component Fx and the fore-and-aft component Fy of the target thrust, The angle θ from the straight line connecting the center of gravity of the hull and the turning center of the thruster of the azimuth thruster to the center line of the hull, (Relationship 1) Fxcos α−Fxsin(α−θ) / (tan βcos θ + sin θ) = Fysin α−Fysin(α−θ) / (cos θ + sin θ / tan β), A ship steering system calculated by.

2. A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a control device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, a control device that controls the azimuth thruster by operating the control device, A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel, In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the control device, The thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters, and the combination of the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β are calculated and selected so as to obtain the target thrust, In the parallel movement mode, the control device selects, from combinations of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull, a combination in which the larger of the value of the thruster azimuth difference |α2 - α1|, which is the difference between the current value α1 of the thruster azimuth when the steering device is operated and the thruster azimuth α2 after the steering device is operated, and the value of the thruster azimuth difference |β2 - β1|, which is the difference between the current value β1 of the thruster azimuth when the steering device is operated and the thruster azimuth β2 after the steering device is operated, is minimized. A ship steering system

3. A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, a control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: the control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel, in the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device, calculates and selects a combination of the thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust, in the parallel movement mode, the control device selects, from combinations of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull, the value of the thruster azimuth difference |α2 - α1|, which is the difference between the current value α1 of the thruster azimuth when the steering device is operated and the thruster azimuth α2 after the steering device is operated, the value of the thruster azimuth difference |β2 - β1|, which is the difference between the current value β1 of the thruster azimuth when the steering device is operated and the thruster azimuth β2 after the steering device is operated, the value of the thruster thrust difference |Tl2 - Tl1|, which is the difference between the current value Tl1 of the thruster thrust when the steering device is operated and the thruster thrust Tl2 after the steering device is operated, Among the values of the thruster thrust difference |Tr2 - Tr1|, which is the difference between the current value Tr1 of the thruster thrust when operating the steering device and the thruster thrust Tr2 after operating the steering device, A ship steering system that selects a combination such that the maximum value is minimized.

4. A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, A steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, A control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel, In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device, Calculates and selects a combination of the thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust, In the parallel movement mode, the control device From among the combinations of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull, The estimated arrival time required to change from the thruster azimuth α1 when operating the steering device to the thruster azimuth α2 after operating the steering device, The estimated arrival time required to change from the thruster azimuth β1 when operating the steering device to the thruster azimuth β2 after operating the steering device, The estimated arrival time required to change from the thruster thrust Tl1 when operating the steering device to the thruster thrust Tl2 after operating the steering device, Among the estimated arrival times required to change from the thruster thrust Tr1 when operating the steering device to the thruster thrust Tr2 after operating the steering device, A ship steering system that selects a combination such that the maximum value is minimized.

5. A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, A steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, A control device that controls the azimuth thruster by operating the control device; A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel; In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the control device; The thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters, and the combination of the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β are calculated and selected so as to obtain the target thrust; In the parallel movement mode, the control device Among the combinations of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull, In a selectable range considering other factors excluding the time required for the azimuth thruster to turn, the thruster azimuth difference |α2 - α1|, which is the difference between the current value α1 of the thruster azimuth when operating the control device and the thruster azimuth α2 after operating the control device, and the current value β1 of the thruster azimuth when operating the control device, and the thruster azimuth difference |β2 - β1|, which is the difference between the thruster azimuth β2 after operating the control device, a ship steering system that selects a combination that minimizes the larger of the two values.

6. A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, A control device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, A control device that controls the azimuth thruster by operating the control device; A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel; In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the control device; The thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters, and the combination of the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β are calculated and selected so as to obtain the target thrust; In the parallel movement mode, the control device By performing control similar to when the hull moves forward or backward, the fore-and-aft component of the thruster azimuth and the thruster thrust are increased or decreased according to the increase or decrease of the second operation amount, so that as the reference values of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters that are left-right symmetric, the thruster azimuth α0 and the thruster thrust Tl0 of the azimuth thruster on the port side of the hull and the thruster azimuth β0 and the thruster thrust Tr0 of the azimuth thruster on the starboard side of the hull are calculated. From the combinations of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull in the parallel movement mode, Among the value of the thruster azimuth difference |α2 - α0| which is the difference between the thruster azimuth α0 and the thruster azimuth α2 after operating the steering device, the value of the thruster azimuth difference |β2 - β0| which is the difference between the thruster azimuth β0 and the thruster azimuth β2 after operating the steering device, the value of the thruster thrust difference |Tl2 - Tl0| which is the difference between the thruster thrust Tl0 and the thruster thrust Tl2 after operating the steering device, and the value of the thruster thrust difference |Tr2 - Tr0| which is the difference between the thruster thrust Tr0 and the thruster thrust Tr2 after operating the steering device, A ship steering system that selects a combination such that the maximum value becomes the minimum.

7. In the parallel movement mode, the control device modifies the magnitude of the target thrust according to the value of the first operation amount, The ship steering system according to claim 1, wherein the combinations of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β are calculated and selected so as to obtain the corrected target thrust.

8. A pair of azimuth thrusters provided on the hull so as to be left-right symmetric with respect to the center line of the hull, A steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, A control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel. In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device. The control device calculates and selects a combination of a thruster azimuth α and a thruster azimuth β of the pair of azimuth thrusters and thruster thrusts Tl and Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust. In the parallel movement mode, the control device When a state in which the same first operation amount and the second operation amount are output from the steering device exceeds a predetermined period, Among combinations of the thruster azimuth α, the thruster azimuth β, the thruster thrust Tl, and the thruster thrust Tr that generate the target thrust, selects another combination in which the sum of the thruster thrust Tl and the thruster thrust Tr becomes smaller, A ship steering system that changes from the current combination to the other combination.

9. The steering device can output a third operation amount for instructing turning of the hull or a change in the hull azimuth. In the parallel movement mode, the control device The ship steering system according to claim 1, wherein at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters is changed by the third operation amount output from the steering device.

10. A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a steering device that outputs a first operation amount for instructing the traveling direction of the hull and a second operation amount for instructing the propulsion force of the hull, and a control device that controls the azimuth thruster by operating the steering device. A ship steering system comprising: The control device includes a parallel movement mode in which the azimuth thruster is controlled so that the hull moves in parallel. In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device. The control device calculates and selects a combination of a thruster azimuth α and a thruster azimuth β of the pair of azimuth thrusters and thruster thrusts Tl and Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust. The steering device can output a third operation amount for instructing turning of the hull or a change in the hull azimuth. In the parallel movement mode, the control device The at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters is changed by the third operation amount output from the steering device, and the change is a combination of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull, the lateral component Fx and the fore-and-aft component Fy of the target thrust, the angle θ from the straight line connecting the center of gravity of the hull and the turning center of the thruster of the azimuth thruster to the center line of the hull, the target turning component M of the hull determined according to the third operation amount output from the steering device, A ship steering system calculated by (Relational Expression 2) {−Fy(tan β cos θ + sin θ) + M} / {sin(α − θ) − cos α(tan β cos θ + sin θ)} = {−Fx(cos θ + sin θ / tan β) + M} / {sin(α − θ) − sin α(cos θ + sin θ / tan β)}. **Claim 11**: A pair of azimuth thrusters provided on a hull so as to be symmetric with respect to the center line of the hull, a steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, a control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: the control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel, in the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device, calculates and selects a combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust, the steering device can output a third operation amount indicating turning of the hull or a change in the hull azimuth, in the parallel movement mode, the control device changes at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters by the third operation amount output from the steering device, and the change is a combination of the thruster azimuth α of the azimuth thruster on the port side of the hull and the thruster azimuth β of the azimuth thruster on the starboard side of the hull, The transverse component Fx' and the longitudinal component Fy' of the target thrust obtained by reducing the target thrust of the hull determined according to the first operation amount and the second operation amount, The angle θ from the straight line connecting the center of gravity of the hull and the turning center of the thruster of the azimuth thruster to the center line of the hull, The target turning moment M of the hull determined according to the third operation amount output from the steering device, A ship steering system calculated by (relational expression 2) {−Fy'(tanβcos θ + sin θ) + M} / {sin(α − θ) − cos α(tanβcos θ + sin θ)} = {−Fx'(cosθ + sin θ / tanβ) + M} / {sin(α − θ) − sinα(cosθ + sin θ / tanβ)}.

12. In the parallel movement mode, the control device Changes the thruster azimuth of the pair of azimuth thrusters to an angle at which the turning moment becomes larger, The ship steering system according to claim 9, wherein the thruster thrust of the pair of azimuth thrusters is changed according to the magnitude of the target turning moment.

13. Equipped with a measuring device for measuring the hull azimuth, In the parallel movement mode, the control device The ship steering system according to claim 9, wherein the target turning moment is determined so that the difference between the hull azimuth measured by the measuring device and the target hull azimuth becomes zero.

14. A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, A steering device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, A control device that controls the azimuth thruster by operating the steering device, A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves in parallel, In the parallel movement mode, the control device determines the target thrust of the hull according to the first operation amount and the second operation amount of the steering device, The combination of the thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β is calculated and selected so as to obtain the target thrust, The steering device can output a third operation amount indicating turning of the hull or a change in hull azimuth, In the parallel movement mode, the control device The at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters is changed by the third operation amount output from the control device. The ship steering system further includes a measuring instrument for measuring the hull azimuth. In the parallel movement mode, the control device determines a target turning component so as to make zero the difference between the hull azimuth measured by the measuring instrument and the target hull azimuth. And in the parallel movement mode, the control device calculates the difference between the hull azimuth measured by the measuring instrument and the target hull azimuth. A ship steering system in which the target turning component is a value obtained by multiplying the difference by a coefficient and adding a value obtained by multiplying the time derivative of the difference by a coefficient.

15. A pair of azimuth thrusters provided on the hull so as to be symmetric with respect to the center line of the hull, a control device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, a control device that controls the azimuth thruster by operating the control device, A ship steering system comprising: The control device includes a parallel movement mode in which the azimuth thruster is controlled so that the hull moves in parallel. In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the control device. The combination of the thruster azimuth α and the thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and the thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β is calculated and selected so as to obtain the target thrust. The control device can output a third operation amount for instructing turning of the hull or a change in hull azimuth. In the parallel movement mode, the control device The at least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters is changed by the third operation amount output from the control device. The ship steering system further includes a measuring instrument for measuring the hull azimuth. In the parallel movement mode, the control device determines a target turning component so as to make zero the difference between the hull azimuth measured by the measuring instrument and the target hull azimuth. And in the parallel movement mode, the control device calculates the difference between the hull azimuth measured by the measuring instrument and the target hull azimuth. A ship steering system in which the target turning component is a value obtained by multiplying a value obtained by subtracting the turning angular velocity from a value obtained by multiplying the difference by a coefficient by a coefficient. A pair of azimuth thrusters provided on a hull so as to be symmetrical about the center line of the hull, A control device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, A control device that controls the azimuth thruster by operating the control device, A ship steering system comprising: The control device includes a parallel movement mode for controlling the azimuth thruster so that the hull moves parallel, In the parallel movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the control device, A combination of a thruster azimuth α and a thruster azimuth β of the pair of azimuth thrusters and a thruster thrust Tl and a thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β are calculated and selected so as to obtain the target thrust, The control device can output a third operation amount for instructing turning of the hull or a change in hull azimuth, In the parallel movement mode, the control device At least one of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters is changed by the third operation amount output from the control device, The ship steering system further includes a measuring device for measuring the hull azimuth, In the parallel movement mode, the control device Determines a target turning component so that the difference between the hull azimuth measured by the measuring device and the target hull azimuth becomes zero, And, in the parallel movement mode, the control device When the third operation amount is output, the target turning component of the hull is determined according to the third operation amount, A ship steering system that performs control to determine the target turning component so that the difference between the hull azimuth measured by the measuring device and the target hull azimuth becomes zero when the third operation amount is not output.

17. In the parallel movement mode, the control device The ship steering system according to claim 13, wherein the hull azimuth at at least one of the point at which the parallel movement mode is switched or the point at which the third operation amount becomes zero is set as the target hull azimuth. A pair of azimuth thrusters provided on a hull so as to be symmetrical about the center line of the hull, A control device that outputs a first operation amount indicating the traveling direction of the hull and a second operation amount indicating the propulsion force of the hull, A control device that controls the azimuth thruster by operating the control device, A ship steering system comprising: The control device includes a translational movement mode for controlling the azimuth thruster so that the hull moves translationally. In the translational movement mode, the control device determines a target thrust of the hull according to the first operation amount and the second operation amount of the steering device, and calculates and selects a combination of the thruster azimuth α and thruster azimuth β of the pair of azimuth thrusters and the thruster thrust Tl and thruster thrust Tr of the pair of azimuth thrusters corresponding to the thruster azimuth α and the thruster azimuth β so as to obtain the target thrust. The steering device includes a cruising mode for controlling the azimuth thruster so that the hull moves forward or backward. In the cruising mode, The reference values of the thruster azimuths of the pair of azimuth thrusters are symmetric about the left and right. The forward and backward components of the thruster azimuth and the thruster thrust of the pair of azimuth thrusters are increased or decreased according to the increase or decrease of the second operation amount. By further increasing or decreasing the thruster azimuth set according to the second operation amount according to the increase or decrease of the first operation amount, A ship steering system for performing forward and backward movement, straight-ahead turning, backward turning, and neutral stop of the hull.

19. The steering device can output a third operation amount for instructing turning of the hull or a change in the hull azimuth. In the cruising mode, the control device Either increases or decreases the thruster azimuth set according to the second operation amount according to the increase or decrease of the third operation amount instead of the first operation amount, or The ship steering system according to claim 18, wherein the thruster azimuth set according to the second operation amount is increased or decreased according to the first operation amount and then further increased or decreased according to the third operation amount.

20. The ship steering system according to claim 1, wherein at least one of the first operation amount and the second operation amount is remotely provided to the control device.

21. The hull is provided with a receiver of a remote control device. The ship steering system according to claim 20, wherein the transmitter of the remote control device is provided on the ship that the hull moves.

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