Ship propulsion systems

Abstract

The present invention provides a ship propulsion system that can minimize the discomfort experienced by the operator while heel control is being performed. [Solution] The ship's propulsion system comprises: a propulsion engine provided on each side of the ship's hull in the left-right direction with respect to the ship's center; a rotation speed sensor for detecting the rotation speed of the propulsion section of the propulsion engine; a trim angle adjustment unit for adjusting the trim angle of each propulsion engine on both sides with respect to the ship's hull; and a control unit for controlling the trim angle adjustment unit. The control unit, while performing heel control, adjusts the rotation speed of the propulsion engines so that the difference in rotation speed between the propulsion engines on both sides decreases if the difference in rotation speed detected by the rotation speed sensor is greater than or equal to a preset reference difference.

Description

TECHNICAL FIELD

[0001] The present invention relates to a marine vessel propulsion system.

BACKGROUND ART

[0002] Conventionally, various techniques for automatically controlling marine vessel propulsion systems have been proposed to improve the stability, acceleration performance, maximum speed, fuel efficiency and the like of a marine vessel during navigation.

[0003] For example, Patent Document 1 discloses a configuration related to heel control for controlling the heel angle of a marine vessel. In this configuration, when it is determined that the marine vessel is not in a turning state according to the steering angle of the steering mechanism of the marine vessel, a difference is generated in the left and right lift forces of the marine vessel, so that the heel angle of the marine vessel is increased in the direction corresponding to the steering angle of the steering mechanism.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0004]

PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

[0005] Incidentally, when performing heel control, the trim angles relative to the hull are made different among a plurality of propulsion units provided on the left and right sides of the hull. At this time, the operating resistance of a propulsion portion such as a propeller provided in each propulsion unit may differ between the left and right propulsion units in accordance with the magnitude of the trim angle. For example, when a propulsion unit is tilted rearward relative to the hull in the propulsion direction of the marine vessel, the thrust generated by the propulsion unit acts obliquely downward toward the rear in the propulsion direction. As a result, the operating resistance of the propulsion unit increases compared to a case where the propulsion unit is not tilted rearward in the propulsion direction of the marine vessel and the thrust is caused to act rearward in the propulsion direction. Furthermore, for example, if the propulsion system is tilted forward relative to the hull in the direction of propulsion, the thrust generated by the propulsion system acts diagonally upward and backward in the direction of propulsion. Compared to the case where the propulsion system is not tilted backward in the direction of propulsion and the thrust acts backward in the direction of propulsion, the operating resistance of the propulsion system is reduced because the distance to the water surface is shorter.

[0006] If the operating resistance experienced by the propulsion system differs between the left and right thrusters, a difference in rotational speed may occur between them. This will result in different operating sounds from the left and right thrusters. Furthermore, a tachometer displaying the rotational speeds of the left and right thrusters will show that the rotational speeds are different. As a result, the operator may notice the difference in rotational speeds between the left and right thrusters and feel something is wrong. This invention has been made in view of the above circumstances, and aims to provide a ship propulsion system that can suppress the discomfort felt by the operator while heel control is being performed. [Means for solving the problem]

[0007] To address the above issues, this disclosure adopts the following characteristics. (1) A ship propulsion system according to one aspect of the present disclosure comprises a drive source and a propulsion unit that generates thrust by power transmitted from the drive source, and includes at least one propulsion unit on each side in the left-right direction with respect to the center of the hull, A rotation speed sensor for detecting the rotation speed of the propulsion unit of the propulsion machine, A trim angle adjustment unit for adjusting the trim angle of each of the propulsion units on both the left and right sides relative to the hull, A ship propulsion system comprising a control unit for controlling the trim angle adjustment unit, The control unit, In order to suppress the tilt of the hull in the roll direction, heel control can be performed by adjusting the trim angle in the trim angle adjustment unit so that the trim angle becomes a heel suppression angle set according to the tilt of the hull in the roll direction. While heel control is being performed, if the difference in rotational speed between the left and right thrusters detected by the rotational speed sensor is greater than or equal to a preset reference difference, the rotational speed of the thrusters is adjusted so that the difference in rotational speed between the left and right thrusters becomes smaller.

[0008] (2) In the propulsion system of a ship according to the embodiment of (1) above, the control unit may reduce the rotational speed of the propulsion unit with the higher rotational speed among the propulsion units on both the left and right sides, and bring it closer to the rotational speed of the other propulsion unit with the lower rotational speed.

[0009] (3) In the propulsion system of a ship according to the embodiment of (1) or (2) above, the control unit may perform an adjustment of the rotational speed between the propulsion units on both the left and right sides when it determines that the rotational speed of the propulsion units on both the left and right sides is in a stable state.

[0010] (4) In the propulsion system of a ship according to the embodiment of (3) above, the control unit is: In each of the propulsion units on both the left and right sides, if the range of rotational speed fluctuation within a predetermined time is less than a preset reference range, it may be determined that the rotational speed of the propulsion units on both the left and right sides is in a stable state.

[0011] (5) A propulsion system for a ship according to any one of the embodiments described in (1) to (4) above, further comprising a throttle operation input unit that adjusts the rotational speed of the propulsion unit by an external input, The control unit, If, while adjusting the rotational speed of the thrusters on both the left and right sides to reduce the difference in rotational speed, an operation input is received from the throttle operation input unit, the rotational speed of the thrusters may be adjusted in accordance with the operation input from the throttle operation input unit while maintaining the difference in rotational speed of the thrusters at the time the operation input was received.

[0012] (6) In a ship propulsion system according to any one of the embodiments described in (1) to (5) above, the control unit may be able to perform heel control when it is determined that the ship is moving in a straight line.

[0013] (7) In the propulsion system for a ship according to the embodiment of (6) above, the system further comprises a heel angle detection unit for detecting the heel angle, which is the inclination of the hull in the roll direction, and the control unit may perform heel control when the heel angle is equal to or greater than a preset heel angle reference value.

[0014] (8) In a ship propulsion system according to any one of the embodiments described in (1) to (7) above, the control unit may stop the execution of the heel control when it is determined that the ship is in a turning state.

[0015] (9) In a ship propulsion system according to any one of the embodiments of (1) to (8) above, the control unit is capable of performing trim support control, which adjusts the trim angle in the trim angle adjustment unit so that the trim support angle is set according to a preset ship speed or propulsion engine rotation speed, and in addition to the trim support control, the control unit may perform heel control when preset conditions are met, and adjust the propulsion engine to the heel suppression angle set in the trim angle adjustment unit with respect to the trim support angle of the propulsion engine. [Effects of the Invention]

[0016] According to the embodiment of (1), when heel control is being performed, if the difference in rotational speed between the left and right propellers is greater than or equal to a preset reference difference, the rotational speed of the propellers is adjusted so that the difference in rotational speed between the left and right propellers becomes smaller. In this way, when heel control is performed, the difference in rotational speed between the left and right propellers becomes large, and the difference in rotational speed can be reduced. Therefore, the discomfort felt by the operator due to the difference in rotational speed between the left and right propellers can be suppressed.

[0017] According to the aspect (2), among the propulsion units on both left and right sides, the rotational speed of one propulsion unit having a higher rotational speed is decreased to approach the rotational speed of the other propulsion unit having a lower rotational speed. As a result, the thrust generated by the one propulsion unit with the higher rotational speed is reduced, so that the influence of heel control on the behavior of the hull is suppressed, and an unintended increase in rotational speed by the operator can be prevented. As a result, the sense of discomfort felt by the operator can be reduced.

[0018] According to the aspect (3), when it is determined that the rotational speeds of the propulsion units on both left and right sides are in a stable state, the adjustment of the rotational speeds of the propulsion units is performed. Thereby, the rotational speeds of the propulsion units can be adjusted while the behavior of the hull is stable, and the sense of discomfort felt by the operator can be reduced.

[0019] According to the aspect (4), in each of the propulsion units on both left and right sides, when the fluctuation range of the rotational speed of the propulsion unit within a predetermined time is less than a preset reference fluctuation range, it is determined that the rotational speed of the propulsion unit is in a stable state. Thereby, it is possible to easily determine whether the rotational speeds of the propulsion units on both left and right sides are in a stable state, and the adjustment of the rotational speeds of the propulsion units can be smoothly performed.

[0020] According to the aspect (5), when an operation input from the throttle operation input unit is received while the rotational speeds of the propulsion units are being adjusted, the rotational speeds of the propulsion units are adjusted in accordance with the operation input from the throttle operation input unit while maintaining the difference in the rotational speeds of the propulsion units at the time when the operation input is received. Thereby, the adjustment state of the rotational speeds of the propulsion units can be continued while responding to the operation input according to the intention of the operator. Therefore, the imbalance in rotational speed between the propulsion units can be favorably adjusted while suppressing the operator from feeling a sense of discomfort.

[0021] According to the aspect (6), heel control is enabled when it is determined that the vessel is traveling straight. Thereby, when the vessel is traveling straight, the heel control is smoothly performed, and stability, acceleration performance, maximum speed, fuel efficiency, and the like can be improved.

[0022] According to the aspect (7), heel control is executed when the heel angle is equal to or greater than a preset heel angle reference value. Thereby, under the preset condition that the vessel is traveling straight and the heel angle is large, the heel angle can be suppressed, and the stability, acceleration performance, maximum speed, fuel efficiency, etc. of the vessel can be improved.

[0023] According to the aspect (8), execution of the heel control is stopped when it is determined that the vessel is in a turning state based on the input value of the steering angle. Thereby, when the vessel is in a turning state, it is possible to prevent the turning performance from being impaired by the heel control.

[0024] According to the aspect (9), when a preset condition is satisfied, heel control is executed in addition to trim support control, and the trim angle adjustment unit adjusts the trim support angle of the propulsion unit to a heel suppression angle set based on the trim support angle. Thereby, when the preset condition is satisfied, by executing the heel control in addition to the trim support control, the heel angle of the vessel can be suppressed while automatically adjusting the trim angle. Therefore, the stability, acceleration performance, maximum speed, fuel efficiency, etc. of the vessel can be improved.

Brief Description of the Drawings

[0025] [Figure 1] It is a plan view of the vessel according to the present embodiment. [Figure 2] It is a functional block diagram of the propulsion system of the above-mentioned vessel. [Figure 3] It is a side view of the propulsion unit of the above-mentioned propulsion system. [Figure 4] It is a diagram showing an example of trim support control, heel control, hump control, and bow control that are executed according to the vessel speed in the above-mentioned propulsion system. [Figure 5] It is a diagram showing a state in which trim support control is being performed by the above-mentioned propulsion system. [Figure 6] It is a diagram showing an example of set values of trim support angles in trim support control, heel control, and hump control that are executed according to the vessel speed in the above-mentioned propulsion system. [Figure 7] This diagram shows the above-mentioned vessel in a state where heel control is being performed while it is listing to port. [Figure 8] This diagram shows the above-mentioned vessel in a state where heel control is being performed while it is listing to starboard. [Figure 9] This flowchart shows how heel control is performed when trim support control is being executed. [Figure 10] This flowchart shows the flow of the thruster rotation speed adjustment control performed during heel control in the above-mentioned propulsion system. [Figure 11] This is a timing chart illustrating an example of the operation of the above propulsion system. [Figure 12] This timing chart shows another example of the operation of the above propulsion system. [Modes for carrying out the invention]

[0026] Embodiments of the present invention will be described below with reference to the drawings. In the following description, the directions of front, back, up, down, left, and right will correspond to the orientation of the vessel 1. In this case, arrow FR in the figure indicates the front of the vessel 1, arrow UP indicates the top of the vessel 1, and arrow LH indicates the left side of the vessel 1. The center line CL indicates the center position of the vessel 1 in the left-right direction (width direction).

[0027] Figure 1 is a plan view of the vessel according to this embodiment. Figure 2 is a functional block diagram of the vessel's propulsion system. As shown in Figure 1, the ship 1 comprises a hull 2 ​​and a propulsion system 20 provided on the hull 2. As shown in Figures 1 and 2, the propulsion system 20 comprises a plurality of thrusters 3, an operating unit 7, a detection unit 6 (see Figure 2), and a control unit 8 (see Figure 2).

[0028] (propulsion machine) As shown in Figure 1, the propulsion system 3 includes a right propulsion system 3a located on the right side of the stern 2b, straddling the centerline CL, and a left propulsion system 3b located on the left side of the stern 2b, straddling the centerline CL. The two propulsion systems 3 (right propulsion system 3a and left propulsion system 3b) are located on both sides of the stern 2b of the hull 2, straddling the centerline CL. In other words, the vessel 1 of this embodiment is a so-called twin-propulsion small vessel. In the following description, unless it is necessary to distinguish between the propulsion systems 3a and 3b, they will be referred to collectively as the propulsion system 3.

[0029] Figure 3 is a side view of the propulsion system's thruster. As shown in Figure 3, the propulsion system 3 is, for example, an outboard motor. The propulsion system 3 comprises a casing 31, a drive source 32, a drive shaft 33, a propulsion unit 34, and a shift switching mechanism 35. The casing 31 is attached to a bracket 22 located at the stern 2b via a rudder shaft 36 (swivel shaft) that extends vertically. The propulsion unit 3 is mounted to the hull 2 ​​so as to be rotatable around the rudder shaft 36 by the operation of a rudder actuator 41 (see Figure 2).

[0030] The drive source 32 is, for example, an internal combustion engine. The drive source 32 is housed in the upper part of the casing 31 with the crankshaft aligned vertically. The power (engine speed) of the drive source 32 is set based on the opening of the throttle valve. The throttle valve is driven by the operation of the throttle actuator 42 (see Figure 2). The drive source 32 may also be an electric motor. The drive shaft 33 transmits power generated by the drive source 32 to the propulsion unit 34 via the shift switching mechanism 35. The drive shaft 33 extends vertically within the casing 31. The upper end of the drive shaft 33 is connected to the drive source 32.

[0031] The propulsion unit 34 comprises a propeller shaft 341 and a propeller 342. The propeller shaft 341 is rotatably mounted at the lower end of the casing 31 around an axis along the longitudinal direction. The front end of the propeller shaft 341 is connected to the shift switching mechanism 35 within the casing 31. The propeller 342 is mounted at the rear end of the propeller shaft 341, protruding outward from the casing 31. The propeller 342 rotates integrally with the propeller shaft 341.

[0032] The shift switching mechanism 35 includes a drive gear 351, a forward gear 352, a reverse gear 353, and a clutch 354. The drive gear 351 is located at the lower end of the drive shaft 33. The drive gear 351 is rotatable integrally with the drive shaft 33. The forward gear 352 and the reverse gear 353 are rotatably mounted on the propeller shaft 341, facing each other in the front-rear direction with the drive gear 351 in between. The forward gear 352 and the reverse gear 353 can mesh with the drive gear 351. The forward gear 352 and the reverse gear 353 rotate in opposite directions as the drive gear 351 rotates.

[0033] The clutch 354 switches the power connection or disconnection between the forward gear 352 or the reverse gear 353 and the propeller shaft 341. The clutch 354 is rotatably mounted integrally with the propeller shaft 341. The clutch 354 is movably mounted along the propeller shaft 341 in the forward and backward directions by the operation of the shift actuator 43. By selectively engaging with the forward gear 352 and the reverse gear 353, the clutch 354 switches the rotation direction of the propeller shaft 341 and the propeller 342, thereby switching the propulsion direction of the ship 1.

[0034] The propulsion unit 3 is supported by a bracket 22 attached to the stern 2b of the hull 2, so as to be rotatable around a support shaft 38 that extends in the left-right direction. This allows the propulsion unit 3 to rotate (oscillate) around the support shaft 38 with respect to a reference plane Fv. Here, the reference plane Fv is a virtual plane that lies along the vertical plane passing through the central axis of the support shaft 38 when the hull 2 ​​is simply floating on the water surface. Here, the trim angle θt is defined as the angle at which the direction in which the steering shaft 36 of the propulsion unit 3 extends is inclined in the longitudinal direction around the support shaft 38 with respect to the reference plane Fv. In this embodiment, the trim angle θt is expressed as positive (forward) when the lower end of the propulsion unit 3 moves away from the stern 2b, and negative (negative) when the lower end of the propulsion unit 3 moves towards the stern 2b.

[0035] The thruster 3 has an adjustable trim angle θt via a trim angle adjustment unit 45. The trim angle adjustment unit 45 uses an actuator (not shown) to rotate the thruster 3 around the support shaft 38 within a preset angular range. The thruster 3 is restricted from rotating in the positive and negative directions by abutting against a stopper (not shown) provided on the bracket 22. In this embodiment, the bracket 22 is attached to the mounting surface 2f formed on the stern 2b via an intermediate member 37. The intermediate member 37 is sandwiched between the bracket 22 and the mounting surface 2f. The intermediate member 37 is formed in a wedge shape, with its thickness gradually decreasing in the front-rear direction from top to bottom. As a result, the bracket 22 is positioned at a greater rearward inclination compared to when it is directly attached to the mounting surface 2f without using the intermediate member 37. This configuration allows the propulsion unit 3 to be set to a larger negative rotation angle (rotation range). In this embodiment, the thruster 3 is rotatable, for example, within a range of approximately 20° in the positive direction and approximately -10° in the negative direction with respect to the reference plane Fv.

[0036] (Operation unit) As shown in Figures 1 and 2, the control unit 7 is provided to allow the operator to input controls for steering the vessel 1. In this embodiment, the control unit 7 includes, for example, a steering angle input unit 71, a thrust input unit (throttle operation input unit) 72, a trim angle operation unit 73 (see Figures 2 and 3), and an operation input unit 74.

[0037] The steering angle input unit 71 is located in the cockpit of the hull 2. The steering angle input unit 71 is, for example, a steering wheel that is rotatable in a reciprocating manner. The steering angle input unit 71 receives external input from the operator when changing the course of the vessel 1 (hull 2). That is, the steering angle input unit 71 receives operation by the operator to change the direction (steering angle) of the propulsion engine 3 around the steering axis 36. The steering angle is the angle of inclination of the propulsion engine 3 with respect to the centerline CL in a plan view. In this embodiment, the steering angle of the propulsion engine 3 when the course of the vessel 1 is in the straight direction is set as the reference value (0°). In addition to the steering wheel, the steering angle input unit 71 may also be a joystick, or it may be mounted as a switch on the operation input unit 74, etc.

[0038] The thrust input unit 72 is located in the cockpit of the hull 2. The thrust input unit 72 is, for example, a throttle lever. The thrust input unit 72 receives external input from the operator when changing the thrust of the propulsion engine 3 or the shift position of the propulsion engine 3. The thrust input unit 72 is configured to be displaceable by rotation or sliding. The thrust input unit 72 can move back and forth within an operating area that has three shift areas: forward position F, neutral position N, and reverse position R. When the thrust input unit 72 is in the forward position F, the propulsion engine 3 exerts thrust to move the ship 1 forward. When the thrust input unit 72 is in the reverse position R, the propulsion engine 3 exerts thrust to move the ship 1 backward. The thrust input unit 72 adjusts the rotational speed of the propulsion unit 34 according to its displacement, thereby allowing adjustment of the thrust generated by the propulsion engine 3 when moving the ship 1 forward or backward. When the thrust input unit 72 is in the neutral position N, the drive gear 351 shown in Figure 3 is disconnected from the forward gear 352 and the reverse gear 353, and the propulsion unit 3 does not exert thrust to propel the ship 1.

[0039] As shown in Figure 1, a trim angle control switch is provided near the thrust input section 72 as a trim angle control section 73. The operator of the ship 1 can change the trim angle θt of the propulsion unit 3 by manually operating the trim angle control switch (trim angle control section 73).

[0040] The operation input unit 74 receives various operations on the vessel 1. The operation input unit 74 is configured to be manually operated by the operator, for example, as an MFD (Multi Function Display). The operation input unit 74 may also be an external device such as a portable terminal connected to the vessel 1 by wire or wireless connection.

[0041] (Detection unit) The detection unit 6 shown in Figure 2 detects the state (navigation state) of the vessel 1. In this embodiment, the detection unit 6 includes a position sensor 61, a ship speed sensor 62, a steering angle sensor 63, an inertia sensor (heel angle detection unit) 64, a trim operation sensor 65, a trim angle sensor 66, an actual steering angle sensor 67, and a rotation speed sensor 68. The position sensor 61 detects the position of the thrust input unit 72. The position sensor 61 outputs a detection signal based on the position of the thrust input unit 72 to the control unit 8.

[0042] The ship speed sensor 62 detects the ship speed V of the vessel 1. The ship speed sensor 62 is, for example, a GPS (Global Positioning System) and calculates the ship speed V based on positioning signals from positioning satellites. The ship speed sensor 62 may also be an acoustic or electromagnetic sensor that detects the ship speed (water speed) V of the vessel 1. The ship speed sensor 62 may also estimate the ship speed V based on the engine speed. The ship speed sensor 62 outputs a signal representing the detected ship speed V to the control unit 8.

[0043] The steering angle sensor 63 detects the amount of operation (steering instruction angle) caused by the rotational operation of the steering angle input unit 71. The steering angle sensor 63 outputs a detection signal based on the steering instruction angle of the steering angle input unit 71 to the control unit 8.

[0044] The inertial sensor 64 detects the tilt of the hull 2 ​​in the roll direction, i.e., the heel angle θh. The inertial sensor 64 can also detect the tilt of the hull 2 ​​in the pitch direction, etc. The inertial sensor 64 outputs detection signals based on the detected tilt of the hull 2 ​​in the roll direction to the control unit 8.

[0045] The trim operation sensor 65 detects whether or not an external operation input has been made to the trim angle operation switch, which is the trim angle operation unit 73. The trim operation sensor 65 outputs a detection signal to the control unit 8 indicating whether or not an operation input has been detected.

[0046] The trim angle sensor 66 is provided in the trim angle adjustment unit 45. The trim angle sensor 66 detects the actual trim angle θt adjusted by the trim angle adjustment unit 45. The trim angle sensor 66 outputs a detection signal indicating the detected trim angle θt to the control unit 8.

[0047] The actual steering angle sensor 67 is provided on the steering actuator 41. The actual steering angle sensor 67 detects the actual steering angle of the thruster 3 and outputs it to the control unit 8.

[0048] The rotation speed sensor 68 detects the rotation speed of the propulsion unit 34 in each of the multiple propulsion units 3. The rotation speed sensor 68 outputs a detection signal indicating the detected rotation speed of the propulsion unit 34 to the control unit 8.

[0049] (Control Unit) The control unit 8 comprehensively controls the operation of the ship 1 (propulsion unit 3). The control unit 8 is one or more electronic control units provided by the ship 1. The control unit 8 is realized, for example, by a hardware processor such as a CPU (Central Processing Unit) executing a program (software) stored in a storage unit 80 such as a ROM (Read Only Memory) or RAM (Random Access Memory). Some or all of these components may be realized by hardware (including circuitry) such as an LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), GPU (Graphics Processing Unit), or SOC (System On Chip), or by the cooperation of software and hardware.

[0050] The control unit 8 includes a storage unit 80, an acquisition unit 81, a determination unit 82, and a drive processing unit 83.

[0051] The memory unit 80 stores programs and various data necessary for the navigation of the ship 1, such as trim support control, heel control, hump control, and wedge control. The acquisition unit 81 acquires the detection results of the various sensors of the detection unit 6. The determination unit 82 determines the state of the ship 1 based on the information obtained by the acquisition unit 81 and the information stored in the storage unit 80.

[0052] The drive processing unit 83 controls the operation of various actuators based on the determination result from the determination unit 82 and the information stored in the storage unit 80 and the acquisition unit 81. In this embodiment, if the determination unit 82 determines that predetermined control execution conditions have been met, the drive processing unit 83 controls the operation of the trim angle adjustment unit 45, the steering actuator 41, etc., to perform trim support control, heel control, hump control, and wedge control. In this embodiment, the drive processing unit 83 performs trim support control, heel control, hump control, and wedge control when the vessel 1 is in a straight-ahead state. In this embodiment, the drive processing unit 83 determines that the vessel 1 does not perform wedge control.

[0053] (Trim support control) Figure 4 shows an example of trim support control, heel control, hump control, and wedge control performed in a propulsion system according to the ship's speed. As shown in Figure 4, when the ship 1 is moving straight, in the areas of heel control, hump control, and wedge control, the drive processing unit 83 performs trim support control according to the settings of the operator, for example, based on input from the trim angle control unit 73 and the operation input unit 74.

[0054] Figure 5 shows an example of trim support angle settings for trim support control, heel control, and hump control performed in the propulsion system according to ship speed. As shown in Figure 5, the trim support control adjusts the trim angle θt in the trim angle adjustment unit 45 so that the trim support angle θsp is set according to a preset ship speed V (or propeller rotation speed). In this embodiment, when performing trim support control, the trim support angle θsp is set according to the ship speed V so that stability, acceleration, maximum speed, fuel consumption, etc., are optimized. The trim support angle θsp may also be set according to the propeller rotation speed. For this reason, the ship speed V (or propeller rotation speed) and the trim support angle θsp that optimizes stability, acceleration, maximum speed, fuel consumption, etc., are stored in the memory unit 80 in association with each other. In the example in Figure 6, the trim support angle θsp is set in steps with respect to the ship speed V (or propeller rotation speed).

[0055] The drive processing unit 83 obtains the trim support angle θsp associated with the ship speed, which is acquired by the acquisition unit 81, from the storage unit 80. The drive processing unit 83 controls the trim angle adjustment unit 45 so that the trim angle θt of the thruster 3 approaches the acquired trim support angle θsp. Figure 6 shows the state in which trim support control is being performed by the propulsion system. As shown in Figure 6, when the drive processing unit 83 performs trim support control, it sets the trim support angles θsp of the thrusters 3a and 3b on both the left and right sides to the same value.

[0056] (Heel control) As shown in Figure 4, if the determination unit 82 determines that the ship 1 is moving straight, the ship speed V is equal to or greater than the second threshold V2, and trim support control is being performed, and the preset first condition (pre-set condition) is met, the drive processing unit 83 performs heel control in addition to trim support control. Specifically, the drive processing unit 83 performs heel control in addition to trim support control, that is, both trim support control and heel control, when the ship 1 is moving straight, trim support control is being performed, and the ship speed is equal to or greater than the second threshold V2. In this case, the drive processing unit 83 executes heel control when the heel angle θh, which is the inclination of the hull 2 ​​in the roll direction detected by the inertial sensor 64, is greater than or equal to a preset heel angle reference value θhs (for example, several degrees). In other words, if the heel angle θh is less than the heel angle reference value θhs, the drive processing unit 83 does not execute heel control and continues trim support control.

[0057] When the drive processing unit 83 performs heel control, it sets a target value for the heel suppression angle θd according to the heel angle θh of the hull 2. Here, the heel suppression angle θd is the trim angle of the propulsion units 3 on both the left and right sides to suppress the tilt of the hull 2 ​​in the roll direction. The drive processing unit 83 calculates a heel suppression angle θd that can effectively suppress the tilt of the hull 2 ​​in the roll direction according to the heel angle θh of the hull 2 ​​using a pre-set calculation formula.

[0058] The drive processing unit 83 sets the heel suppression angle θd based on the trim support angle θsp of the thruster 3 at that time. The drive processing unit 83 sets the heel suppression angle θd of one thruster 3 in the left-right direction to a value greater than the trim support angle θsp, and sets the heel suppression angle θd of the other thruster 3 in the left-right direction to a value smaller than the trim support angle θsp.

[0059] Figure 7 shows the state of heel control when the ship is tilting to port. Figure 8 shows the state of heel control when the ship is tilting to starboard. For example, as shown in Figure 7, when the hull 2 ​​is tilted to the port side, the drive unit 83 sets the heel suppression angle θd2 of the right-side propulsion engine 3a to a value greater than the trim support angle θsp, and the heel suppression angle θd1 of the left-side propulsion engine 3b to a value less than the trim support angle θsp. For example, as shown in Figure 8, when the hull 2 ​​is tilted to the starboard side, the drive unit 83 sets the heel suppression angle θd1 of the left-side propulsion engine 3b to a value greater than the trim support angle θsp, and the heel suppression angle θd2 of the right-side propulsion engine 3a to a value less than the trim support angle θsp.

[0060] The drive processing unit 83 calculates heel suppression angles θd1 and θd2 based on the heel angle θh of the hull 2 ​​at that time, acquired by the acquisition unit 81, using the trim support angle θsp set at that time as a reference. The drive processing unit 83 calculates a trim angle addition value Δθt1 to be added to one of the propulsion units 3 in the left-right direction, and a trim angle subtraction value Δθt2 to be subtracted from the other propulsion unit 3 in the left-right direction, based on a preset calculation formula, with respect to the reference trim support angle θsp. Here, it is preferable that the absolute values ​​of the trim angle addition value Δθt1 and the trim angle subtraction value Δθt2 are the same. Here, the absolute values ​​of the trim angle addition value Δθt1 and the trim angle subtraction value Δθt2 are less than or equal to a preset size. However, the absolute values ​​of the trim angle addition value Δθt1 and the trim angle subtraction value Δθt2 may be different.

[0061] When the hull 2 ​​is tilted to the port side, the drive unit 83 calculates the heel suppression angle θd1 of the left propulsion unit 3b using the following equation (1), and the heel suppression angle θd2 of the right propulsion unit 3a using the following equation (2). θd1 = θsp - Δθt2 (1) θd² = θsp + Δθt¹ (2) When the hull 2 ​​is tilted to the starboard side, the drive unit 83 calculates the heel suppression angle θd1 of the left propulsion unit 3b using the following equation (3), and the heel suppression angle θd2 of the right propulsion unit 3a using the following equation (4). θd1 = θsp + Δθt1 (3) θd² = θsp - Δθt² (4)

[0062] The drive processing unit 83 uses the calculated heel suppression angles θd1 and θd2 as target values ​​and uses the trim angle adjustment unit 45 to adjust the trim angle θt of the thrusters 3 (3a, 3b) so that it approaches the heel suppression angles θd1 and θd2.

[0063] If the determination unit 82 determines that the ship speed V has fallen below a preset third threshold V3 while heel control is being performed, the drive processing unit 83 stops the execution of heel control. Here, the third threshold V3 is set lower than the second threshold V2.

[0064] When heel control is being performed, the control unit 8 adjusts the rotation speed of the thrusters 3 so that the difference in rotation speed between the left and right thrusters 3 becomes smaller if there is a large difference in rotation speed between the left and right thrusters 3 (hereinafter, this may be referred to as thruster 3 rotation speed adjustment control).

[0065] Therefore, when the determination unit 82 receives a detection signal from the rotation speed sensor 68 indicating the rotation speed of the propulsion unit 34 while heel control is being performed, it calculates the absolute value of the difference between the rotation speed of the propulsion unit 34 of the right propulsion machine 3a and the rotation speed of the propulsion unit 34 of the left propulsion machine 3b (hereinafter, this may be simply referred to as the rotation speed difference).

[0066] The determination unit 82 determines whether or not the preset start conditions for the rotation speed adjustment control of the thruster 3 are met. Here, the following conditions A to C can be presented as the start conditions for the rotational speed adjustment control of the thruster 3. Condition A: The calculated rotational speed difference is greater than or equal to a predetermined reference difference. Condition B: The rotational speeds of each thruster 3 on both the left and right sides are in a stable state. Condition C: No change occurs in the trim angle θt of the thrusters 3 on both the left and right sides. The determination unit 82 determines that the conditions for starting the rotation speed adjustment control of the thruster 3 are met if all of the above conditions A to C are satisfied. Note that conditions other than those A to C may be used as the conditions for starting the rotation speed adjustment control of the thruster 3.

[0067] If the drive processing unit 83 determines that the start conditions for adjusting the rotation speed of the thruster 3 have been met, it adjusts the rotation speed of the thruster 3 so that the difference between the rotation speed of the thruster unit 34 of the right thruster 3a and the rotation speed of the thruster unit 34 of the left thruster 3b becomes smaller. In this embodiment, the rotation speed of the thruster 3 with the higher rotation speed among the thruster unit 34 of the right thruster 3a and the thruster unit 34 of the left thruster 3b is reduced to bring it closer to the rotation speed of the other thruster 3 with the lower rotation speed. It is preferable for the control unit 8 to make the rotation speed of the right thruster 3a and the rotation speed of the left thruster 3b the same. For example, if the rotational speed of the right thruster 3a is high, the control unit 8 will reduce the rotational speed of the right thruster 3a to bring it closer to the rotational speed of the left thruster 3b. If the rotational speed of the left thruster 3b is high, the control unit 8 will reduce the rotational speed of the left thruster 3b to bring it closer to the rotational speed of the right thruster 3a.

[0068] As described above, when the control unit 8 receives an input from the thrust input unit 72 by the operator while the rotational speed of the thrusters 3 (thrusters 3a and 3b) on both the left and right sides is being adjusted so that the difference in rotational speed between them is small, the control unit 8 adjusts the rotational speed of the thrusters 3 in accordance with the input from the thrust input unit 72. Specifically, the control unit 8 adjusts the rotational speed of the thruster 3 in response to the operation input from the thrust input unit 72, while maintaining the difference in rotational speed of the thruster 3 at the time the operation input is received.

[0069] Furthermore, when heel control is being performed, if the determination unit 82 receives a steering angle input from the steering angle sensor 63 and the steering angle input unit 71, it determines whether the vessel 1 is in a turning state based on the received steering angle input value. If the drive processing unit 83 determines that the vessel 1 is in a turning state, it stops the execution of trim support control and heel control. Furthermore, if the determination unit 82 determines that it has received an operation input from the trim angle operation unit 73 by the operator while heel control is being performed, the drive processing unit 83 stops the execution of heel control.

[0070] (Hump control) Furthermore, as shown in Figure 4, if the determination unit 82 determines that the predetermined second condition is met when the vessel 1 is moving straight and the ship speed V is equal to or greater than the first threshold V1, the drive processing unit 83 performs hump control. The drive processing unit 83 also performs hump control when the vessel 1 is moving straight and the ship speed V is equal to or greater than the first threshold V1, and the ship speed V is less than the second threshold V2. Hump ​​control is performed to suppress excessive lift of the bow 2a when the bow 2a is significantly raised relative to the stern 2b. When performing hump control, the drive processing unit 83 sets the trim angles θt of the propellers 3a and 3b on both the left and right sides to the same value.

[0071] (Bogen control) Furthermore, the drive processing unit 83 performs wedge control when the ship speed V is less than the first threshold V1. Wedge control steers the multiple propulsion units 3 in the yaw direction in a direction that intersects the longitudinal direction of the hull 2. When the ship 1 is moving straight and the ship speed V is less than the first threshold V1, wedge control rotates the left and right propulsion units 3 around the swivel axis in opposite directions and at the same steering angle. Wedge control reduces the forward thrust acting on the entire hull 2 ​​compared to when the propulsion units 3 are arranged parallel to the longitudinal direction of the hull 2, making it possible to sail the hull 2 ​​at low speed or very low speed. In this embodiment, the specific details of wedge control are not limited in any way.

[0072] (Control method for the propulsion system) Next, the control method for the propulsion system will be explained. The processes described below are executed repeatedly, for example, at a predetermined control cycle (e.g., several tens of milliseconds).

[0073] Here, the trim support control is executed at an appropriate timing according to the setting by the vessel operator. In the trim support control, the control unit 8 sets a trim support angle θsp that optimizes stability, acceleration, maximum speed, fuel efficiency and the like according to the vessel speed V, as a target value. The control unit 8 controls the trim angle adjustment unit 45 such that the trim angles θt of the propulsion units 3 on both left and right sides approach the trim support angle θsp set as the target value.

[0074] FIG. 9 is a flowchart showing an execution method of heel control when the trim support control is executed. When the trim support control is being executed, in step S141, the control unit 8 acquires the detection result of the vessel speed from the vessel speed sensor 62 by the acquisition unit 81 at a predetermined control cycle. In step S142, the control unit 8 determines whether or not the vessel speed V is equal to or greater than a second threshold value V2 based on the detection result of the vessel speed sensor 62.

[0075] When the determination result in step S142 is "No" (V<V2), the process is ended, the processes from step S141 are repeated at every predetermined control cycle, and the trim support control is continued. When the determination result in step S142 is "Yes" (V≧V2), the process proceeds to step S143, and the control unit 8 brings the heel control into an executable state. In other words, the control unit 8 sets the heel control to a standby state.

[0076] Next, in step S144, the acquisition unit 81 acquires the detection result of the heel angle θh of the hull 2 from the inertial sensor 64. In step S145, the control unit 8 determines whether or not the heel angle θh is equal to or greater than a heel angle reference value θhs based on the detection result of the inertial sensor 64.

[0077] When the determination result in step S145 is "No" (θh<θhs), the process returns to step S144, and step S144 is repeatedly executed after a predetermined control cycle elapses. When the determination result in step S145 is "Yes" (θh≧θhs), the process proceeds to step S146.

[0078] In step S146, the control unit 8 performs heel control in addition to trim support control. In step S146, the control unit 8 sets the heel suppression angle θd according to the heel angle θh of the hull 2. The control unit 8 sets the heel suppression angle θd based on the trim support angle θsp of the propulsion engine 3 at that time. Based on the heel angle θh of the hull 2 ​​at that time, acquired by the acquisition unit 81, the drive processing unit 83 calculates a trim angle addition value Δθt1 to be added to one propulsion engine 3 in the left-right direction and a trim angle subtraction value Δθt2 to be subtracted from the other propulsion engine 3 in the left-right direction, based on a preset calculation formula, with the trim support angle θsp as the reference. If the hull 2 ​​is tilted to port, the drive unit 83 calculates the heel suppression angle θd1 of the left propulsion unit 3b using equation (1) above, and the heel suppression angle θd2 of the right propulsion unit 3a using equation (2) above. If the hull 2 ​​is tilted to starboard, the drive unit 83 calculates the heel suppression angle θd1 of the left propulsion unit 3b using equation (3) above, and the heel suppression angle θd2 of the right propulsion unit 3a using equation (4) above. The drive processing unit 83 uses the calculated heel suppression angles θd1 and θd2 as target values ​​and causes the trim angle adjustment unit 45 to adjust the trim angle θt of the thrusters 3 (3a, 3b).

[0079] In step S147, it is determined whether a predetermined stop condition for stopping heel control has been met during the execution of heel control. In this embodiment, the predetermined stop condition for stopping heel control is, for example, Condition 1: When heel control is being performed, if the ship speed V falls below a preset third threshold V3, Condition 2: When the operator receives an input from the trim angle control unit 73, This can be used as an example.

[0080] If the result of step S147 is "No" (neither condition 1 nor 2 is met), proceed to step S149. If the result of the determination in step S147 is "Yes" (at least one of conditions 1 or 2 is met), the process proceeds to step S148, where heel control is stopped and only trim support control continues.

[0081] In step S149, the control unit 8 determines whether or not the vessel 1 is turning. In this case, the control unit 8 uses the steering angle sensor 63 to determine whether or not the vessel 1 is turning based on the steering angle input value from the steering angle input unit 71.

[0082] If the result of the determination in step S149 is "No" (meaning that ship 1 is not turning, i.e., ship 1 is moving in a straight line), the process is terminated, and after a predetermined control cycle has elapsed, the above process is repeated. If the result of step S149 is "Yes" (meaning that vessel 1 is turning), the process proceeds to step S150, and the execution of trim support control and heel control is stopped.

[0083] Figure 10 is a flowchart showing the flow of thruster rotation speed adjustment control performed during heel control in the propulsion system. During the execution of heel control in step S146, the control unit 8 performs rotational speed adjustment control of the thruster, as shown in Figure 10.

[0084] In step S1461, the control unit 8 determines whether or not a change in the trim angle θt has occurred in at least one of the thrusters 3 on both the left and right sides, as one of the conditions for starting the rotation speed adjustment control of the thrusters 3.

[0085] If the result of step S1461 is "Yes" (meaning a change in the trim angle θt has occurred), the process ends and the process from step S1461 is repeated at predetermined control cycles. If the result of the determination in step S1461 is "No" (meaning no change has occurred in the trim angle θt), proceed to step S1462.

[0086] In step S1462, the control unit 8 acquires the rotational speed of the propulsion units 34 of the thrusters 3 (thrusters 3a, 3b) on both the left and right sides, as detected by the rotational speed sensor 68, at a predetermined control cycle.

[0087] In step S1463, the control unit 8 determines whether the rotational speed of each of the thrusters 3 on both sides is in a stable state (condition A) as one of the conditions for starting the rotational speed adjustment control of the thrusters 3. For this reason, the determination unit 82 determines that the rotational speeds of both thrusters 3 are in a stable state if the fluctuation range of the rotational speed of the thrusters 3 within a predetermined time is less than a preset reference fluctuation range. To give a specific example, the determination unit 82 determines that the rotational speeds of both thrusters 3 are in a stable state if the fluctuation range of the rotational speed of both thrusters 3 on the left and right sides is less than 100 rpm in 2 seconds.

[0088] If the result of step S1463 is "No" (indicating that the rotational speed is not stable), the process ends, and the process from step S1461 is repeated at predetermined control cycles. If the result of step S1463 is "Yes" (i.e., the rotation speed is stable), proceed to step S1464.

[0089] In step S1464, the control unit 8 calculates the difference in rotational speed between the propulsion unit 34 of the right-side thruster 3a and the propulsion unit 34 of the left-side thruster 3b.

[0090] In step S1465, the control unit 8 determines whether the calculated rotational speed difference is greater than or equal to a preset reference difference, as one of the conditions for starting rotational speed adjustment control of the thruster 3 (Condition B).

[0091] If the result of step S1465 is "No" (the rotational speed difference is less than the reference difference), the process ends and the process from step S1461 is repeated at predetermined control cycles. If the result of step S1465 is "Yes" (i.e., the rotation speed difference is greater than or equal to the standard difference), proceed to step S1466.

[0092] In step S1466, the control unit 8 adjusts the rotational speed of the thrusters 3 so that the difference in rotational speed between the right thruster 3a and the left thruster 3b becomes smaller. The control unit 8 reduces the rotational speed of the thruster 3 with the higher rotational speed, and brings it closer to the rotational speed of the other thruster 3 with the lower rotational speed.

[0093] In step S1467, while the rotational speed of the thrusters 3 (thrusters 3a and 3b) on both the left and right sides is being adjusted to reduce the difference in rotational speed between them, the control unit 8 determines whether or not it has received an operation input from the thrust input unit 72 via manual operation by the operator.

[0094] If the result of step S1467 is "No" (no operation input has been received and no manual operation has been performed), the process ends and the process from step S1461 is repeated at predetermined control cycles. If the result of step S1467 is "Yes" (meaning that an operation input has been accepted and a manual operation has been performed), proceed to step S1468.

[0095] In step S1468, the control unit 8 adjusts the rotational speed of the thruster 3 in response to the operation input from the thrust input unit 72. The control unit 8 maintains the rotational speed difference of the thruster 3 at the time the operation input is received and adjusts the rotational speed of the thruster 3 in response to the operation input from the thrust input unit 72. After the completion of step S1468, the process returns to step S1467 and is repeated until the operation input from the thrust input unit 72 by the operator's manual operation is completed.

[0096] Figure 11 is a timing chart showing an example of the operation of the propulsion system. In Figure 11, for each of the "Ship Speed ​​Determination Flag," "Straight Track Determination Flag," and "Heel Control Implementation Determination Flag," "0" indicates that the determination result in the control unit 8 is "No," and "1" indicates that the determination result in the control unit 8 is "Yes."

[0097] As shown in Figure 11, for example, when the ship speed V increases due to the operation of the thrust input unit 72 by the helmsman and exceeds the second threshold V2 (time t1), the ship speed determination flag in step S142 of the control unit 8 changes from "0" to "1". In the example in Figure 11, at this time, the straight-ahead determination flag in step S149 is "0" based on the steering angle of the steering angle input unit 71, and it is determined that the ship 1 is not in a straight-ahead state. Therefore, the heel control implementation determination flag in step S150 becomes "0", and heel control (and trim support control) is not performed.

[0098] Subsequently, when the ship speed V decreases due to the operator's operation of the thrust input unit 72 and falls below the third threshold V3 (time t2), the ship speed determination flag in step S142 changes from "1" to "0". At this time, the straight-ahead determination flag is "0" due to the steering angle of the steering angle input unit 71, so the heel control implementation determination flag remains "0", and heel control is not performed.

[0099] Next, when the steering angle input unit 71 is operated by the operator, and the steering angle to the left becomes smaller than a predetermined left steering angle threshold (time t3), the straight-ahead determination flag changes from "0" to "1". Furthermore, when the steering angle is switched from left to right by the operator's steering angle input unit 71, and the steering angle to the right becomes greater than or equal to a predetermined right steering angle threshold (time t4), the straight-ahead determination flag returns from "1" to "0". At this time, since the ship speed V is less than the second threshold V2, the ship speed determination flag remains "0", and the heel control implementation determination flag also remains "0".

[0100] Next, when the steering angle input unit 71 is operated by the operator, and the steering angle to the right becomes smaller than the right steering angle threshold (time t5), the straight-ahead determination flag changes from "0" to "1". Furthermore, when the steering angle input unit 71 is operated by the operator, and the steering angle switches from right to left, and the steering angle to the left becomes greater than or equal to the left steering angle threshold (time t6), the straight-ahead determination flag returns from "1" to "0". At this time, since the ship speed V is less than the second threshold V2, the ship speed determination flag remains "0", and the heel control implementation determination flag also remains "0".

[0101] Subsequently, when the steering angle input unit 71 by the ship's operator causes the steering angle to the left to become smaller than the left steering angle threshold (time t7), the straight-ahead determination flag changes from "0" to "1". Then, when the ship speed V increases due to the operation of the thrust input unit 72 by the operator and exceeds the second threshold V2 (time t8), the ship speed determination flag changes from "0" to "1". As a result, the ship 1 is moving in a straight line and the ship speed V is equal to or greater than the second threshold V2, so the heel control implementation determination flag changes from "0" to "1", and heel control (and trim support control) is implemented.

[0102] Figure 12 is a timing chart showing another example of the propulsion system's operation. In Figure 12, for each of the "operation input judgment flag," "rotation speed stability judgment flag," and "trim angle change judgment flag," "0" indicates that the judgment result in the control unit 8 is "No," and "1" indicates that the judgment result in the control unit 8 is "Yes." In addition, for the "rotation speed matching execution judgment flag," "0" indicates the standby state, "1" indicates the stable state, "2" indicates the change state, and "3" indicates the state in which the instruction lever opening is matched to the actual lever opening.

[0103] As shown in Figure 12, when the opening of the thrust input section 72 increases due to the operator's actions (from time t11 to time t12), the operation input determination flag in the control unit 8, which indicates that an operation input has been made, changes from "0" to "1". Accordingly, the signal value of the instruction lever opening for changing the rotational speed of the propulsion unit 34, which is output from the control unit 8 to each propulsion unit 3, corresponds to the amount of operation performed on the thrust input section 72. Each thruster 3 increases its rotational speed from time t11 to time t12 in response to changes in the signal value of the instruction lever opening. When the rotational speed of the thruster 3 is changing, the rotational speed stability determination flag, which indicates the stable state of the thruster 3's rotational speed, changes from "1" to "0". Also, in the example in Figure 12, while the rotational speed of the thruster 3 is changing from time t11 to time t12, the trim angle θt of the thrusters 3 on both the left and right sides during trim support control is the same. As a result, the rotational speed matching determination flag changes from "1", which indicates that the difference in rotational speed between the thrusters 3 on both the left and right sides is stable and below the reference difference, to "2", which indicates that the rotational speed of the thrusters 3 is changing while maintaining a state where the difference in rotational speed between the thrusters 3 on both the left and right sides is below the reference difference.

[0104] When the operator's operation of the thrust input section 72 ends (time t12), the change in the rotational speed of the thruster 3 stops with a response delay (time t13). Subsequently, if the range of fluctuation in the rotational speed of the thruster 3 remains below the standard fluctuation range for a predetermined time (time t13 to time t14), the rotational speed stability determination flag changes from "0" to "1", and it is determined that the rotational speed of the thruster 3 is in a stable state. Also, the rotational speed matching execution determination flag returns from "2" to "1".

[0105] Subsequently, at time t15, heel control is initiated. If the trim angle θt of the left thruster 3b and the trim angle θt of the right thruster 3a are different, a difference will occur between the rotational speed of the left thruster 3b (solid line in Figure 12) and the rotational speed of the right thruster 3a (dotted line in Figure 12) due to the difference in operating resistance experienced by the thruster 34 in water (times t15 to t16). At time t15, when heel control is initiated, the rotational speed stability determination flag changes from "1" to "0". Also, the rotational speed matching execution determination flag changes from "1" to "3", and the instruction lever opening is adjusted to the actual lever opening. In S1461 above, since a change in the trim angle θt occurs between time t15 and time t16, the trim angle change determination flag changes from "0" to "1". In this case, since a change in the trim angle θt occurs in step S1461, the rotational speed adjustment of the thruster in step S1466 is not performed.

[0106] At time t16, when the change in the trim angle θt of the thrusters 3 on both the left and right sides due to heel control stops, the trim angle change determination flag in S1461 changes from "1" to "0". The rotation speed matching determination flag changes from "3" to "0" because the change in the trim angle θt has stopped, and waits until the rotation speed stabilizes.

[0107] From time t16 onward, if the fluctuation range of the rotational speed of the thruster 3 remains below the reference fluctuation range for a predetermined period of time (time t17), in step S1463, the step rotational speed stability determination flag changes from "0" to "1". As a result, in step S1465, the rotational speed adjustment execution determination flag changes from "0" to "1", and the rotational speed adjustment of the thruster 3 in step S1466 is executed. The control unit 8 outputs signal values ​​for the opening of the instruction levers to change the rotational speeds of the thrusters 3a and 3b on both the left and right sides. Specifically, by maintaining the opening of the instruction lever for the right thruster 3a and decreasing the opening of the instruction lever for the left thruster 3b, the rotational speed of the left thruster 3b is reduced and brought closer to the rotational speed of the right thruster 3a.

[0108] Subsequently, at time t18, when the opening of the thrust input section 72 decreases due to the operator's actions (time t18 → time t19), in step S1467, the operation input determination flag indicating that an operation input has been made changes from "0" to "1". As a result, the control unit 8 changes the rotation speed of each thruster 3 on both the left and right sides in response to the operation input to the thrust input section 72, while maintaining the rotation speed difference between the thrusters 3 on both sides in the left and right directions at that time.

[0109] As described above, in this embodiment, when heel control is being performed, if the difference in rotational speed between the left and right thrusters 3 exceeds a preset reference difference, the propulsion system 20 adjusts the rotational speed of the thrusters 3 so that the difference in rotational speed between the left and right thrusters 3 becomes smaller. This makes it possible to reduce the difference in rotational speed when heel control causes a large difference in rotational speed between the left and right thrusters 3. Therefore, it is possible to reduce the feeling of discomfort that the operator may experience due to the difference in rotational speed between the left and right thrusters 3.

[0110] Furthermore, the propulsion system 20 of this embodiment reduces the rotational speed of the thruster 3 with the higher rotational speed among the thrusters 3 on both the left and right sides, bringing it closer to the rotational speed of the other thruster 3 with the lower rotational speed. As a result, the thrust generated by the thruster 3 with the higher rotational speed is reduced, which suppresses the influence on the behavior of the hull 2 ​​through heel control and prevents an unintended increase in rotational speed by the operator. Consequently, the sense of unease experienced by the operator can be reduced.

[0111] Furthermore, the propulsion system 20 of this embodiment adjusts the rotation speed of the propulsion engines 3 when it is determined that the rotation speed of the propulsion engines 3 on both the left and right sides is in a stable state. This allows the rotation speed of the propulsion engines 3 to be adjusted while the behavior of the hull 2 ​​is stable, thereby reducing any sense of unnaturalness experienced by the operator.

[0112] Furthermore, the propulsion system 20 of this embodiment determines that the rotational speed of each of the thrusters 3 on both the left and right sides is stable if the fluctuation range of the rotational speed of the thruster 3 within a predetermined time is less than a preset reference fluctuation range. This makes it easy to determine whether the rotational speed of the thrusters 3 on both the left and right sides is stable, and allows for smooth adjustment of the rotational speed of the thrusters 3.

[0113] Furthermore, in this embodiment, when the propulsion system 20 receives an input from the thrust input unit 72 while adjusting the rotational speed of the thrusters 3, it adjusts the rotational speed of the thrusters 3 in response to the input from the thrust input unit 72, while maintaining the difference in rotational speed of the thrusters 3 at the time the input was received. This allows the adjustment of the rotational speed of the thrusters 3 to continue in response to the operator's intentions. Therefore, the imbalance in rotational speed between the thrusters 3 can be adjusted effectively while minimizing any discomfort the operator may feel.

[0114] Furthermore, the propulsion system 20 of this embodiment is capable of performing heel control when it is determined that the vessel 1 is moving in a straight line. This allows for smooth heel control when the vessel 1 is moving in a straight line, resulting in improved stability, acceleration, maximum speed, fuel efficiency, and other performance characteristics.

[0115] Furthermore, the propulsion system 20 of this embodiment performs heel control when the heel angle θh is greater than or equal to a preset heel angle reference value θhs. As a result, under the preset conditions that the vessel 1 is moving in a straight line and the heel angle θh is large, the heel angle θh can be suppressed, thereby improving the stability, acceleration, maximum speed, fuel efficiency, etc., of the vessel 1.

[0116] Furthermore, the propulsion system 20 of this embodiment stops executing heel control when it is determined that the vessel 1 is in a turning state. This prevents the turning ability from being hindered by heel control when the vessel 1 is in a turning state.

[0117] Furthermore, the propulsion system 20 of this embodiment performs heel control in addition to trim support control when preset conditions are met, and adjusts the trim angle adjustment unit 45 to a heel suppression angle θd set based on the trim support angle θsp of the propulsion engine 3. As a result, when preset conditions are met, heel control is performed in addition to trim support control, which allows for automatic adjustment of the trim angle θt while suppressing the heel angle θh of the vessel 1. Therefore, when transitioning from a state in which heel control is being performed to another state, the transition can be made smoothly so as not to impair the stability, acceleration, maximum speed, fuel efficiency, etc. of the vessel 1, or cause the operator to feel any discomfort.

[0118] It should be noted that the present invention is not limited to the embodiments described above with reference to the drawings, and various modifications are conceivable within its technical scope. For example, in the above embodiment, trim support control, heel control, etc., are performed based on the ship speed V, but instead of the ship speed V, trim support control, heel control, etc., may be performed based on the rotational speed of the propulsion engine 3.

[0119] Furthermore, in the above embodiment, examples were given of a case where only trim support control is performed while the vessel 1 is moving straight, and a case where both trim support control and heel control are performed according to the ship speed V. However, it is also possible to perform only heel control while the vessel 1 is moving straight, according to the ship speed V.

[0120] Furthermore, in the above embodiment, one thruster 3 is provided on each side in the left-right direction, but multiple thrusters may be provided on each side in the left-right direction. Furthermore, the control procedures and content executed by the control unit 8 can be modified as appropriate. Furthermore, the configuration in the above embodiment is just one example of the present invention, and various modifications are possible without departing from the spirit of the invention. [Explanation of Symbols]

[0121] 1 ship 2 hull 3 Propulsion machine 3a Right propulsion machine (propulsion machine) 3b Left propulsion machine (propulsion machine) 6. Detection Unit 8 Control Unit 20 Propulsion System 32 Power source 34 Promotion Department 45 Trim angle adjustment section 64. Inertial sensor (heel angle detection unit) 68. Rotation speed sensor 72. Thrust input section (throttle operation input section)

Claims

1. A propulsion unit having a drive source and a propulsion unit that generates thrust by power transmitted from the drive source, and having at least one propulsion unit on each side in the left-right direction with respect to the center of the hull, A rotation speed sensor for detecting the rotation speed of the propulsion unit of the propulsion machine, A trim angle adjustment unit for adjusting the trim angle of each of the propulsion units on both the left and right sides relative to the hull, A ship propulsion system comprising a control unit for controlling the trim angle adjustment unit, The control unit, In order to suppress the tilt of the hull in the roll direction, heel control can be performed by adjusting the trim angle in the trim angle adjustment unit so that the trim angle becomes a heel suppression angle set according to the tilt of the hull in the roll direction. While heel control is being performed, if the difference in rotational speed between the left and right thrusters detected by the rotational speed sensor is greater than or equal to a preset reference difference, the rotational speed of the thrusters is adjusted so that the difference in rotational speed between the left and right thrusters becomes smaller. A ship's propulsion system.

2. The control unit reduces the rotational speed of the thruster with the higher rotational speed among the thrusters on both the left and right sides, bringing it closer to the rotational speed of the other thruster with the lower rotational speed. The propulsion system for a ship according to claim 1.

3. When the control unit determines that the rotational speed of the thrusters on both the left and right sides is stable, it performs an adjustment of the rotational speed of the thrusters on both the left and right sides. A ship propulsion system according to claim 1 or 2.

4. The control unit, In each of the propulsion units on both the left and right sides, if the range of rotational speed fluctuation within a predetermined time is less than a preset reference range, it is determined that the rotational speed of the propulsion units on both the left and right sides is in a stable state. The propulsion system for a ship according to claim 3.

5. The system further includes a throttle control input unit that adjusts the rotational speed of the thruster based on external input, The control unit, When adjusting the rotational speed of the thrusters so that the difference in rotational speed between the left and right thrusters is reduced, and an operation input is received from the throttle operation input unit, the rotational speed of the thrusters will be adjusted in accordance with the operation input from the throttle operation input unit while maintaining the difference in rotational speed of the thrusters at the time the operation input was received. A ship propulsion system according to claim 1 or 2.

6. The control unit, When it is determined that the hull is moving in a straight line, the heel control can be executed. A ship propulsion system according to claim 1 or 2.

7. The system further includes a heel angle detection unit that detects the heel angle, which is the inclination of the hull in the roll direction, The control unit, The heel control is executed when the heel angle is equal to or greater than a preset heel angle reference value. The propulsion system for a ship according to claim 6.

8. The control unit, If, while the heel control is being performed, it is determined that the hull is in a turning state, the execution of the heel control is stopped. A ship propulsion system according to claim 1 or 2.

9. The control unit, It is possible to perform trim support control, which adjusts the trim angle in the trim angle adjustment unit so that the trim support angle is set according to a preset ship speed or propulsion engine rotation speed. When pre-set conditions are met, the heel control is executed in addition to the trim support control, and the thruster is adjusted by the trim angle adjustment unit to the heel suppression angle set based on the trim support angle of the thruster. A ship propulsion system according to claim 1 or 2.

Images