Ship propulsion systems

Abstract

The present invention provides a ship propulsion system that enables smooth transitions between states, particularly when transitioning from a state of hump control to another state. [Solution] The ship's propulsion system comprises a propeller installed on the hull, a trim angle adjustment unit for adjusting the trim angle of the propeller, and a control unit for controlling the trim angle adjustment unit. The control unit is capable of performing hump control, which involves adjusting the trim angle of the propeller using the trim angle adjustment unit, with a preset lower limit of the trim angle, in order to suppress the tilt of the hull in the pitch direction. When stopping the execution of hump control from a state where hump control is being performed, the trim angle adjustment unit adjusts the trim angle of the propeller according to the state of the hull.

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. For example, when the bow is lifted significantly relative to the stern and the pitch angle of the hull relative to the horizontal plane increases, a so-called hump state is reached, which may impair the forward visibility of the marine vessel.

[0003] For example, Patent Document 1 discloses that when the pitch angle of the hull relative to the horizontal plane exceeds a set value, the trim angle of the propulsion unit is reduced to suppress the hump state of the hull.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in marine vessels, not only hump control but also other controls may be executed according to the navigation state of the marine vessel. For example, different controls may be executed when the marine vessel is in a straight traveling state and when it is in a turning state. Further, when the operator performs a manual operation, each unit may be in a state different from the control that was automatically performed. As described above, when shifting from a state in which hump control is being performed to another state, it is desired to smoothly perform the state transition so that the stability and the like of the marine vessel are not impaired and the operator does not feel a sense of discomfort or the like. This invention has been made in view of the above circumstances, and aims to provide a ship propulsion system that can smoothly transition from a state in which hump control is being performed to another state. [Means for solving the problem]

[0006] (1) A propulsion system for a ship 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 a propulsion machine provided on the hull, A trim angle adjustment unit for adjusting the trim angle of the propulsion unit 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 pitch tilt of the hull, a hump control is possible in which the trim angle of the propulsion system is adjusted by the trim angle adjustment unit, using a preset lower limit value for the trim angle. When stopping the execution of the hump control from the state in which the hump control is being performed, the trim angle of the propulsion system is adjusted by the trim angle adjustment unit according to the state of the hull.

[0007] (2) In the propulsion system of a ship relating to the embodiment of (1) above, The control unit, An acceleration trim angle adjustment mode is provided to adjust the trim angle when stopping the execution of the hump control from a state in which the hump control is being performed during the acceleration of the hull, The system may also include a deceleration trim angle adjustment mode for adjusting the trim angle when stopping the execution of the hump control from a state in which the hump control is being performed during the deceleration of the hull.

[0008] (3) In the propulsion system of a ship relating to the embodiment of (2) above, The control unit, In the acceleration trim angle adjustment mode, if the trim angle of the propeller at the time the execution of the hump control is stopped is smaller than the trim angle reference value which is set to be larger than the lower limit of the trim angle and in the direction in which the propeller stands upright in front of the propulsion direction of the hull, the trim angle of the propeller may be adjusted so that the trim angle becomes the trim angle reference value.

[0009] (4) In the propulsion system of a ship relating to the embodiment of (3) above, 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 the hull is accelerating and the execution of the trim support control and the hump control is stopped, the execution of the hump control may be disabled in the acceleration trim angle adjustment mode, which disables the control to reduce the trim angle of the propulsion system by the trim support control.

[0010] (5) In a ship propulsion system relating to any one of the embodiments described in (2) to (4) above, The control unit, In the deceleration trim angle adjustment mode, if the trim angle of the propulsion unit at the time the execution of the hump control is stopped is smaller than the trim angle reference value which is set to be larger than the lower limit of the trim angle and in the direction in which the propulsion unit stands upright in front of the propulsion direction of the hull, the trim angle of the propulsion unit may be adjusted so that the trim angle becomes the trim angle reference value.

[0011] (6) In the propulsion system of a ship relating to the embodiment of (5) above, 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 the hull is decelerating and the execution of the trim support control and the hump control is stopped, the deceleration trim angle adjustment mode may enable the trim support control to reduce the trim angle of the propulsion system.

[0012] (7) In a ship propulsion system relating to any one of the embodiments described in (1) to (6) above, The system further includes a trim angle control unit that operates the trim angle adjustment unit via external input, The control unit, The system includes a manual trim angle adjustment mode that is executed when the execution of the hump control is stopped by receiving an operation input from the trim angle control unit while the hump control is being performed. In the manual operation trim angle adjustment mode, if the trim angle of the propulsion unit at the time the execution of the hump control is stopped is smaller than a trim angle reference value which is set to be larger than the lower limit of the trim angle and in the direction in which the propulsion unit stands upright in front of the propulsion direction of the hull, the trim angle of the propulsion unit may be adjusted so that the trim angle becomes the trim angle reference value. [Effects of the Invention]

[0013] According to the embodiment of (1), when stopping the execution of hump control from a state in which hump control is being performed, the trim angle of the propulsion system is adjusted by the trim angle adjustment unit according to the state of the hull. This makes it possible to smoothly transition from the state in which hump control is being performed to other states.

[0014] According to the embodiment of (2), by having an acceleration trim angle adjustment mode and a deceleration trim angle adjustment mode, it is possible to perform transitions to states appropriate for when the execution of hump control is stopped from a state in which hump control is being performed during hull acceleration, and when the execution of hump control is stopped from a state in which hump control is being performed during hull deceleration.

[0015] According to the aspect (3), in the trim angle adjustment mode during acceleration, when the trim angle of the propulsion unit at the time of stopping the execution of the hump control is smaller than the trim angle reference value, the trim angle of the propulsion unit is adjusted so that the trim angle becomes the trim angle reference value. In this way, when the trim angle of the propulsion unit at the time of stopping the execution of the hump control is smaller than the trim angle reference value, the navigation efficiency can be improved by increasing the trim angle to the trim angle reference value.

[0016] According to the aspect (4), when stopping the execution of the hump control from a state where the trim support control and the hump control are being executed during acceleration of the hull, the control for reducing the trim angle of the propulsion unit by the trim support control is disabled. Thereby, in the subsequent trim support control, the trim angle of the propulsion unit becomes the same angle as when the hump control was being executed, or an angle larger than that. That is, it is possible to suppress the navigation efficiency from decreasing due to the trim angle of the propulsion unit becoming excessively small.

[0017] According to the aspect (5), in the trim angle adjustment mode during deceleration, when the trim angle of the propulsion unit at the time of stopping the execution of the hump control is smaller than the trim angle reference value, the trim angle of the propulsion unit is adjusted so that the trim angle becomes the trim angle reference value. In this way, when the trim angle of the propulsion unit at the time of stopping the execution of the hump control is smaller than the trim angle reference value, the navigation efficiency can be improved by increasing the trim angle to the trim angle reference value.

[0018] According to the aspect (6), when stopping the execution of the hump control from a state where the trim support control and the hump control are being executed during deceleration, the control for reducing the trim angle of the propulsion unit by the trim support control is made executable. During deceleration, the trim angle is smaller than that during acceleration. Therefore, the trim support control can be effectively executed while suppressing the decrease in navigation efficiency.

[0019] According to the embodiment of (7), when an operation input is received from the trim angle control unit while hump control is being performed, if the trim angle of the propeller at the time the execution of hump control is stopped is smaller than the trim angle reference value, the trim angle of the propeller is adjusted so that the trim angle becomes the trim angle reference value. In this way, if the trim angle of the propeller at the time the execution of hump control is stopped is smaller than the trim angle reference value, the efficiency of navigation can be increased by increasing the trim angle to the trim angle reference value. [Brief explanation of the drawing]

[0020] [Figure 1] This is a plan view of a vessel according to this embodiment. [Figure 2] This is a functional block diagram of the propulsion system of the above-mentioned vessel. [Figure 3] This is a side view of the propulsion system's thruster. [Figure 4] This figure shows an example of trim support control, heel control, hump control, and wedge control performed according to the ship's speed in the above-mentioned propulsion system. [Figure 5] This diagram shows the state of trim support control being performed by the above propulsion system. [Figure 6] This figure shows an example of the trim support angle settings for trim support control, heel control, and hump control performed according to the ship speed in the above 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 diagram shows the above vessel performing hump control. [Figure 10] This figure shows examples of ship speed thresholds in hump control. [Figure 11] This flowchart shows how to perform hump control when trim support control is being executed. [Figure 12]This is a flowchart showing the flow of the hump control stop process in the propulsion system. [Figure 13] This is a timing chart illustrating an example of the operation of the above propulsion system. [Figure 14] This timing chart shows another example of the operation of the above propulsion system. [Modes for carrying out the invention]

[0021] 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 of the vessel 1. The center line CL extends in the front-rear direction at the center position in the left-right direction (width direction) of the vessel 1.

[0022] 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).

[0023] (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 the left and right 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.

[0024] 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).

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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 when the lower end of the propulsion unit 3 moves away from the stern 2b, and negative when the lower end of the propulsion unit 3 moves towards the stern 2b. In this embodiment, rotating the propulsion unit 3 in the positive direction is expressed as increasing the trim angle θt, and rotating the propulsion unit 3 in the negative direction is expressed as decreasing the trim angle θt.

[0030] 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 trim angle θt when the thruster 3 is rotated to its most negative position is defined as the lower limit of the trim angle θtd (for example, around θt = -10° in Figure 3). 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).

[0031] (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 72, a trim angle control unit 73, and an operation input unit 74.

[0032] 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.

[0033] 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 propeller 3 or the shift position of the propeller 3. The thrust input unit 72 is configured to be able to move back and forth 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 propeller 3 exerts thrust to move the ship 1 forward. When the thrust input unit 72 is in the reverse position R, the propeller 3 exerts thrust to move the ship 1 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 propeller 3 does not exert thrust to propel the ship 1.

[0034] 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).

[0035] 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, 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.

[0036] (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 64, a trim operation sensor 65, a trim angle sensor 66, and an actual steering angle sensor 67. The position sensor 61 detects the position of the thrust input unit 72. Based on the position of the thrust input unit 72, which is, for example, a throttle lever that indicates the lever opening, the position sensor 61 detects the lever opening of the thruster 3. The position sensor 61 outputs a detection signal based on the position of the thrust input unit 72 to the control unit 8.

[0037] As shown in Figure 2, 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.

[0038] 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.

[0039] 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 also detects the tilt of the hull 2 ​​in the pitch direction, i.e., the pitch angle θp. The inertial sensor 64 outputs detection signals based on the detected tilt of the hull 2 ​​in the roll and pitch directions to the control unit 8.

[0040] The trim operation sensor 65 detects whether or not an 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.

[0041] 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.

[0042] 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.

[0043] (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.

[0044] The control unit 8 includes a storage unit 80, an acquisition unit 81, a determination unit 82, and a drive processing unit 83.

[0045] 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.

[0046] 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 a predetermined condition has 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.

[0047] (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 vessel 1 is moving straight, the drive processing unit 83 can perform trim support control in the areas of heel control, hump control, and wedge control as determined by the determination unit 82, for example, according to the settings of the operator based on input from the trim angle operation unit 73 and the operation input unit 74.

[0048] 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, in the 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 advance. 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).

[0049] 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 sides in the left-right direction to the same value.

[0050] (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 that the preset conditions are 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] (Hump control) Figure 9 shows a ship performing hump control. If the determination unit 82 determines that the preset conditions are met, the drive processing unit 83 executes hump control. If the determination unit 82 determines that the preset conditions are met while trim support control is being executed, the drive processing unit 83 can execute hump control in addition to trim support control. As shown in Figure 9, hump control is performed to suppress excessive lift of the bow 2a when the bow 2a is significantly lifted relative to the stern 2b and the pitch angle θp is large. When performing hump control, the drive unit 83 sets the trim angles θt of the propellers 3a and 3b on both sides in the left and right directions to the same value. When performing hump control, the drive unit 83 rotates the propeller 3 in a negative direction from the state where the trim angle θt = 0°. In hump control, the drive unit 83 adjusts the trim angle θt of the propeller 3 with the lower limit of the trim angle θtd as the lower limit.

[0055] Figure 10 shows examples of ship speed thresholds in hump control. As will be described in detail later, the drive processing unit 83 enables hump control when the ship speed V of the hull 2 ​​is within a preset speed range. Specifically, as shown in Figure 10, the drive processing unit 83 executes hump control when the ship speed V is within a set speed range if it is greater than or equal to a preset first threshold V1 and less than a preset second threshold V2 during the acceleration of the hull 2. The drive processing unit 83 enables hump control when the ship speed V becomes greater than or equal to a preset first threshold V1 during the acceleration of the hull 2. The drive processing unit 83 stops executing hump control when it is executing hump control during the acceleration of the hull 2 ​​and the ship speed V becomes greater than or equal to a second threshold V2 which is greater than the first threshold V1. Furthermore, the drive processing unit 83 enables hump control when the ship speed V is less than the first threshold V1 during acceleration of the hull 2, and the lever opening of the propulsion unit 3 is equal to or greater than a preset reference opening.

[0056] Furthermore, when the hull 2 ​​is decelerating, the drive processing unit 83 determines that the ship speed V is within the set speed range and executes hump control when the ship speed V is higher than a preset fourth threshold V4 and less than or equal to the third threshold V3. The drive processing unit 83 enables hump control when the ship speed V is less than or equal to the third threshold V3, which is less than the second threshold V2, during the deceleration of the hull 2. The drive processing unit 83 stops executing hump control when it is executing hump control during the deceleration of the hull 2 ​​and the ship speed V is less than or equal to the fourth threshold V4, which is less than the first threshold V1. Furthermore, the drive processing unit 83 enables hump control when the ship speed V is less than or equal to the fifth threshold V5, which is less than the second threshold V2 and greater than the third threshold V3, and the pitch angle θp of the ship 2 is greater than or equal to a preset third reference pitch angle, during the deceleration of the hull 2.

[0057] Furthermore, the drive processing unit 83 may be configured to perform hump control when it is determined that the ship speed V is within the set speed range and the hull 2 ​​is turning.

[0058] When the drive unit 83 stops the execution of hump control from a state in which hump control is being performed, it adjusts the trim angle θt of the propulsion unit 3 using the trim angle adjustment unit 45 according to the state of the hull 2. When the drive unit 83 stops the execution of hump control from a state in which hump control is being performed, it can execute the following trim angle adjustment modes: acceleration trim angle adjustment mode, deceleration trim angle adjustment mode, and manual operation trim angle adjustment mode. In each of the acceleration trim angle adjustment mode, deceleration trim angle adjustment mode, and manual operation trim angle adjustment mode, the trim angle θt of the propulsion unit 3 is adjusted by the trim angle adjustment unit 45 according to the state of the hull 2.

[0059] (Trim angle adjustment mode during acceleration) When the hull 2 ​​is accelerating, the drive unit 83 executes the acceleration trim angle adjustment mode if it stops executing the hump control from the state in which hump control is being performed. Specifically, when the hull 2 ​​is accelerating and the ship speed V becomes equal to or greater than the second threshold V2 while hump control is being performed, and the execution of hump control is stopped, the drive unit 83 executes the acceleration trim angle adjustment mode.

[0060] In acceleration trim angle adjustment mode, if the trim angle θt of at least one propulsion unit 3 is smaller than a preset trim angle reference value θts at the time the execution of hump control is stopped, the trim angle adjustment unit 45 adjusts the trim angle θt of all propulsion units 3 so that the trim angle θt of all propulsion units 3 becomes the trim angle reference value θts. Here, the trim angle reference value θts is set in the direction (positive direction) where the propulsion unit 3 stands upright in front of the propulsion direction of the hull 2 ​​and the trim angle θt increases, relative to the trim angle lower limit value θtd. In this embodiment, the trim angle reference value θts is, for example, around θt = -5°. This prevents the state in which the trim angle θt of the propulsion units 3 remains smaller than the trim angle reference value θts after the execution of hump control is stopped during acceleration, thus preventing the strongly suppressed hump state from continuing.

[0061] In acceleration trim angle adjustment mode, if trim support control was being executed at the time the execution of hump control is stopped, the execution of hump control will be stopped from the state in which both trim support control and hump control are being executed. In this case, the drive processing unit 83 will be unable to execute control to reduce the trim angle θt of the thruster 3 in the subsequent trim support control. In other words, after the execution of hump control is stopped, the drive processing unit 83 can control the trim angle θt of the thruster 3 in trim support control to maintain the trim angle θt of the thruster 3 at the trim angle θt at the time the execution of hump control was stopped, or to make the trim angle θt larger in the positive direction than the trim angle θt at the time the execution of hump control was stopped.

[0062] (Trim angle adjustment mode during deceleration) When the hull 2 ​​is decelerating, the drive unit 83 executes the deceleration trim angle adjustment mode when it stops executing hump control from a state in which hump control is being performed. Specifically, when the hull 2 ​​is decelerating, and it stops executing hump control when the ship speed V falls below the fourth threshold V4, the drive unit 83 executes the deceleration trim angle adjustment mode.

[0063] In deceleration trim angle adjustment mode, if the trim angle θt of at least one thruster 3 is smaller than the trim angle reference value θts at the time the hump control is stopped, the trim angle adjustment unit 45 adjusts the trim angle θt of all thrusters 3 so that the trim angle θt of all thrusters 3 becomes the trim angle reference value θts. This prevents the state of strongly suppressing the hump from continuing even during deceleration, after the hump control is stopped, by maintaining a state where the trim angle θt of the thrusters 3 is smaller than the trim angle reference value θts.

[0064] In deceleration trim angle adjustment mode, if trim support control was being executed when hump control is stopped, the execution of hump control will be stopped from the state where both trim support control and hump control are being executed. In this case, the drive processing unit 83 will be able to execute control to reduce the trim angle θt of the thruster 3 in the subsequent trim support control. The hump state during deceleration has a smaller pitch angle θp than the hump state during acceleration. Therefore, even if the trim angle θt of the thruster 3 is reduced in trim support control, it is less likely to cause any discomfort, and thus control to reduce the trim angle θt of the thruster 3 is made possible.

[0065] (Manual operation trim angle adjustment mode) When the drive processing unit 83 receives an operation input from the trim angle operation unit 73 while hump control is being performed, it stops the execution of hump control. In this case, the drive processing unit 83 executes the manual operation trim angle adjustment mode. In the manual operation trim angle adjustment mode, if the trim angle θt of at least one thruster 3 is smaller than the trim angle reference value θts at the time the execution of hump control is stopped, the trim angle adjustment unit 45 adjusts the trim angle θt of the thrusters 3 so that the trim angle θt of all thrusters 3 becomes the trim angle reference value θts. This prevents the state of strongly suppressing the hump from continuing even during manual operation, by keeping the trim angle θt of the thrusters 3 smaller than the trim angle reference value θts after the execution of hump control is stopped.

[0066] (Bogen control) 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 by 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.

[0067] (Control method for the propulsion system) Next, the operation method of 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). Figure 11 is a flowchart showing the flow of the control method for the propulsion system. The flowchart shown in Figure 11 illustrates the processing flow when performing hump control, which is part of the control of the propulsion system 20 executed by the control unit 8. As shown in Figure 11, in step S11, the control unit 8 acquires the ship speed detection result from the ship speed sensor 62 using the acquisition unit 81. In step S11, in order to detect a change in ship speed, the control unit 8 acquires the ship speed detection result multiple times with a predetermined control cycle interval.

[0068] In step S12, the control unit 8 determines, based on the detection result of the ship speed sensor 62, whether the ship speed V of the hull 2 ​​is within a preset speed range. In this case, the control unit 8 determines that the ship speed V is within the set speed range when the ship speed V is greater than or equal to a preset first threshold V1 and less than a preset second threshold V2 during the acceleration of the ship hull 2. When the hull 2 ​​is decelerating, the control unit 8 determines that the ship speed V is within the set speed range if the ship speed V is higher than a preset fourth threshold V4 and less than or equal to the third threshold V3, and executes hump control. Here, the fourth threshold V4 is set, for example, 5 to 10 km / h lower than the first threshold V1. The third threshold V3 is set, for example, 5 to 10 km / h lower than the second threshold V2.

[0069] If the ship speed V is outside the set speed range and the result of the determination in step S12 is "No", proceed to step S13, which will be described later.

[0070] (If the ship speed is determined to be within the set range) If the ship speed V is within the set speed range and the result of the determination in step S12 is "Yes", the system skips to step S15, and the control unit 8 enters a standby state where it can perform hump control. In the following step S16, the control unit 8 determines whether the conditions for executing hump control when the ship speed V is within the set speed range are met.

[0071] Examples of conditions for executing hump control when the ship speed V is within the set speed range include the following conditions a1) and a2). Condition a1) The detected pitch angle θp acquired by the inertial sensor 64 is greater than the preset first reference pitch angle. Condition a2) Based on the actual steering angle detected by the actual steering angle sensor 67, it is determined that the hull 2 ​​is turning. If the ship speed V is within the set speed range, in step S16, the control unit 8 determines that the hump control execution condition is satisfied if at least one of conditions a1) and a2) is satisfied.

[0072] If the result of the determination in step S16 is "No", the process ends, a predetermined control cycle is observed, and the process from step S11 is repeated. If the result of step S16 is "Yes", proceed to step S17.

[0073] (If the ship speed is determined to be outside the set range) If the ship speed V is outside the set speed range and the result of the determination in step S12 is "No", then in step S13, the control unit 8 determines whether or not the acceleration exception condition is satisfied. Examples of exceptions during acceleration include the following conditions b1) to b3). Condition b1) The hull 2 ​​is accelerating. Condition b2) The ship speed V is less than the first threshold V1. Condition b3) The lever opening of the thruster 3, as obtained by the position sensor 61, is greater than a preset reference opening. If the ship speed V is outside the set speed range and all of conditions b1) to b3) are satisfied, the control unit 8 determines in step S13 that the acceleration exception condition is satisfied.

[0074] If the result of step S13 is "Yes", the process skips to step S15, and the control unit 8 enters a standby state where it can perform hump control. In the following step S16, the control unit 8 determines whether the conditions for executing hump control are met when the acceleration exception conditions are satisfied.

[0075] When the ship speed V is outside the set speed range and the acceleration exception condition is satisfied in step S13, the following conditions c1) to c3) are examples of conditions for executing hump control. Condition c1) The lever opening of the thruster 3, as obtained by the position sensor 61, is greater than the preset first lever opening. Condition c2) The detected pitch angle θp acquired by the inertial sensor 64 is greater than the preset reference pitch angle. Condition c3) Based on the actual rudder angle detected by the actual rudder angle sensor 67, it is determined that the hull 2 ​​is turning. Here, the first lever opening may be the same value as the reference opening described above, or it may be a value slightly larger than the reference opening. If the ship speed V is outside the set speed range and the acceleration exception condition is satisfied, in step S16, if at least one of conditions c1) to c3) is satisfied, the control unit 8 determines that the hump control execution condition is satisfied.

[0076] If the result of the determination in step S16 is "No", the process ends, a predetermined control cycle is observed, and the process from step S11 is repeated. If the result of step S16 is "Yes", proceed to step S17.

[0077] (If the ship speed is determined to be outside the set range) If the ship speed V is outside the set speed range and the result of the determination in step S13 is "No", then in step S14, the control unit 8 determines whether or not the deceleration exception condition is satisfied. Examples of exceptions during deceleration include the following conditions d1) and d2). Condition d1) The hull 2 ​​is decelerating. Condition d2) The ship speed V is between the third threshold V3 and the fifth threshold V5. If the ship speed V is outside the set speed range and all conditions d1) and d2) are satisfied, the control unit 8 determines that the deceleration exception condition is satisfied.

[0078] If the result of the judgment in step S14 is "No", the process ends, a predetermined control cycle is observed, and the process from step S11 is repeated. If the result of the determination in step S14 is "Yes", the process proceeds to step S15, and the control unit 8 is put into a standby state where it can perform hump control. In the following step S16, the control unit 8 determines whether the conditions for executing hump control are met when the deceleration exception conditions are satisfied.

[0079] For example, the following condition e1) is an example of a condition for executing hump control when the ship speed V is outside the set speed range and the deceleration exception condition is satisfied. Condition e1) The detected pitch angle θp acquired by the inertial sensor 64 is greater than the preset third reference pitch angle. Here, the third reference pitch angle may be the same value as the first reference pitch angle, or it may be slightly larger than the first reference pitch angle. If the ship speed V is outside the set speed range and the deceleration exception condition is met, in step S16, if condition e1) is met, the control unit 8 determines that the hump control execution condition is met.

[0080] If the result of the determination in step S16 is "No", the process ends, a predetermined control cycle is observed, and the process from step S11 is repeated. If the result of step S16 is "Yes", proceed to step S17.

[0081] (Execution of hump control) In step S17, the control unit 8 performs hump control. In this case, the control unit 8 reduces the trim angle θt of all thrusters 3 to the lower limit of the trim angle.

[0082] After starting the execution of hump control in step S17, the control unit 8 determines in step S18 whether or not predetermined stop conditions for stopping the hump control have been met during the execution of the hump control. In this embodiment, examples of predetermined stop conditions for stopping the hump control include the following conditions g1) to g3). Condition g1) When the ship speed V becomes equal to or greater than the second threshold V2 during acceleration, Condition g2) When decelerating, if the ship speed V becomes less than or equal to the fourth threshold V4, Condition g3) When the operator receives an operational input from the trim angle control unit 73. If at least one of conditions g1) to g3) is satisfied, the control unit 8 determines that the stop condition for stopping the hump control has been satisfied.

[0083] If the result of the determination in step S18 is "No", the process is terminated, a predetermined control cycle is observed, and step S11 is repeated. If the result of the determination in step S18 is "Yes", the process proceeds to step S20, and the execution of the hump control is stopped.

[0084] Figure 12 is a flowchart showing the flow of the hump control stop process in the propulsion system. As shown in Figure 12, in step S20, the execution of hump control is stopped in the following sequence. In step S21, the control unit 8 determines whether or not the stopping condition g1) for hump control during acceleration has been met.

[0085] If the result of step S21 is "No", proceed to step S22. If the result of step S21 is "Yes", proceed to step S24.

[0086] In step S24, the control unit 8 stops the execution of hump control and executes the acceleration trim angle adjustment mode. In acceleration trim angle adjustment mode, if the trim angle θt of at least one thruster 3 is smaller than a preset trim angle reference value θts at the time the hump control is stopped, the trim angle adjustment unit 45 adjusts the trim angle θt of all thrusters 3 so that the trim angle θt of all thrusters 3 becomes the trim angle reference value θts. In acceleration trim angle adjustment mode, if trim support control is being performed at the time the hump control is stopped, the subsequent trim support control will be unable to perform the control to reduce the trim angle θt of the thruster 3.

[0087] In step S22, the control unit 8 determines whether or not the stopping condition g2) for hump control during deceleration has been met.

[0088] If the result of step S22 is "No", proceed to step S23. If the result of step S22 is "Yes", proceed to step S25.

[0089] In step S25, the control unit 8 stops the execution of hump control and executes the deceleration trim angle adjustment mode. In deceleration trim angle adjustment mode, if the trim angle θt of at least one thruster 3 is smaller than the trim angle reference value θts at the time the hump control is stopped, the trim angle adjustment unit 45 adjusts the trim angle θt of all thrusters 3 so that the trim angle θt of all thrusters 3 becomes the trim angle reference value θts. In deceleration trim angle adjustment mode, if trim support control was being performed at the time the hump control is stopped, the subsequent trim support control will enable control to reduce the trim angle θt of the thruster 3.

[0090] In step S23, the control unit 8 determines whether or not the stop condition g3) for the hump control during manual operation has been met.

[0091] If the result of the judgment in step S23 is "No", the process ends, a predetermined control cycle is observed, and the process from step S11 is repeated. If the result of step S23 is "Yes", proceed to step S26.

[0092] In step S26, the control unit 8 stops the execution of hump control and executes the manual trim angle adjustment mode. In manual operation trim angle adjustment mode, if the trim angle θt of at least one thruster 3 is smaller than the trim angle reference value θts at the time the hump control is stopped, the trim angle adjustment unit 45 adjusts the trim angle θt of all thrusters 3 so that the trim angle θt of all thrusters 3 becomes the trim angle reference value θts.

[0093] Figure 13 is a timing chart showing an example of the operation of the propulsion system. In Figure 13, for each of the "Ship Speed ​​Determination Flag," "Hump State Determination Flag," and "Hump 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." As shown in Figure 13, for example, the lever opening increases due to the operation of the thrust input unit 72 by the helmsman, and the ship speed V increases. As the ship speed V increases, when the pitch angle θp exceeds the first reference pitch angle (time t1), the hump state determination flag changes from "0" to "1", and hump control is initiated. At this time, the control unit 8 changes the trim operation determination flag from "0" to "1" and executes the trim operation.

[0094] Subsequently, when the increase in pitch angle θp subsides due to the execution of hump control, and the pitch angle θp decreases, and the pitch angle θp becomes less than or equal to the second reference pitch angle which is smaller than the first reference pitch angle (time t2), the hump determination flag changes from "1" to "0". At this point, the control unit 8 changes the trim operation determination flag from "1" to "0" and stops the execution of hump control.

[0095] Figure 14 is a timing chart showing another example of the propulsion system's operation. As shown in Figure 14, for example, when the lever opening is rapidly increased by the operator's operation of the thrust input unit 72, the above conditions b1) to b3) are met (time t11), and the hump control is initiated, so the hump state determination flag changes from "0" to "1", and the trim operation determination flag changes from "0" to "1".

[0096] Subsequently, when the trim angle θt of thruster 3 decreases to the lower limit of the trim angle due to the execution of hump control (time t12), the trim operation judgment flag changes from "1" to "0" because the trim angle θt cannot be reduced any further for the sake of hump control, and the trim operation stops.

[0097] Subsequently, the hump control process causes the increase in the pitch angle θp to subside, and the pitch angle θp to decrease. When the ship speed V increases further and exceeds the second threshold V2 (time t13), the hump judgment flag changes from "1" to "0", and hump control ends. Then, the control unit 8 changes the trim operation judgment flag from "0" to "1", and the trim operation returns to normal control.

[0098] At this time, since the hump control was stopped during acceleration, the condition of step S21 is met, and the control unit 8 executes the acceleration trim angle adjustment mode and adjusts the trim angle θt of all thrusters 3 so that the trim angle θt of all thrusters 3 becomes the trim angle reference value θts. After that, when the trim angle θt of all thrusters 3 becomes the trim angle reference value θts (time t14), the control unit 8 returns the trim operation determination flag from "1" to "0".

[0099] Thus, in this embodiment, when the propulsion system 20 stops the execution of hump control from a state in which hump control is being performed, the trim angle θt of the propulsion engine 3 is adjusted by the trim angle adjustment unit 45 according to the state of the hull 2. This allows for a smooth transition when moving from a state in which hump control is being performed to another state.

[0100] Furthermore, the propulsion system 20 of this embodiment has an acceleration trim angle adjustment mode and a deceleration trim angle adjustment mode, which allows for transitions to appropriate states when stopping the execution of hump control from a state in which hump control is being performed during acceleration of the hull 2, and when stopping the execution of hump control from a state in which hump control is being performed during deceleration of the hull 2.

[0101] Furthermore, in the acceleration trim angle adjustment mode of this embodiment, if the trim angle θt of the propulsion unit 3 at the time the execution of hump control is stopped is smaller than the trim angle reference value θts, the propulsion system 20 adjusts the trim angle θt of the propulsion unit 3 so that the trim angle θt becomes equal to the trim angle reference value θts. In this way, if the trim angle θt of the propulsion unit 3 at the time the execution of hump control is stopped is smaller than the trim angle reference value θts, the efficiency of navigation can be increased by increasing the trim angle θt to the trim angle reference value θts.

[0102] Furthermore, in this embodiment, when the propulsion system 20 is accelerating the hull 2 ​​and is performing trim support control and hump control, if the execution of hump control is stopped, the control that reduces the trim angle θt of the propulsion engine 3 by trim support control is disabled. As a result, the trim angle θt of the propulsion engine 3 becomes the same angle as when hump control was being performed, or a larger angle. In other words, it is possible to suppress the decrease in navigation efficiency that occurs when the trim angle θt of the propulsion engine 3 becomes smaller.

[0103] Furthermore, in the deceleration trim angle adjustment mode of this embodiment, if the trim angle θt of the propulsion unit 3 at the time the execution of hump control is stopped is smaller than the trim angle reference value θts, the propulsion system 20 adjusts the trim angle θt of the propulsion unit 3 so that the trim angle θt becomes equal to the trim angle reference value θts. In this way, if the trim angle θt of the propulsion unit 3 at the time the execution of hump control is stopped is smaller than the trim angle reference value θts, the efficiency of navigation can be increased by increasing the trim angle θt to the trim angle reference value θts.

[0104] Furthermore, in this embodiment, the propulsion system 20, when decelerating, can perform control to reduce the trim angle θt of the propulsion unit 3 by trim support control when stopping the execution of hump control from a state where trim support control and hump control are being performed. During deceleration, the trim angle θt is smaller compared to during acceleration. Therefore, trim support control can be effectively performed while suppressing a decrease in navigation efficiency.

[0105] Furthermore, in this embodiment, if the propulsion system 20 receives an input from the trim angle control unit 73 while hump control is being performed, it stops the execution of hump control. If the trim angle θt of the propulsion unit 3 at the time the execution of hump control is stopped is smaller than the trim angle reference value θts, the system adjusts the trim angle θt of the propulsion unit 3 so that the trim angle θt becomes equal to the trim angle reference value θts. In this way, if the trim angle θt of the propulsion unit 3 at the time the execution of hump control is stopped is smaller than the trim angle reference value θts, the efficiency of navigation can be increased by increasing the trim angle θt to the trim angle reference value θts.

[0106] 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, various conditions for implementing hump control were illustrated, but these conditions can be changed as appropriate.

[0107] Furthermore, in the above embodiment, trim support control, hump control, etc., are performed based on the ship speed V, but instead of the ship speed V, trim support control, hump control, etc., may be performed based on the rotational speed of the propulsion engine 3.

[0108] Furthermore, in the above embodiment, one thruster 3 is provided on each of the left and right sides, but multiple thrusters may be provided on each of the left and right sides, or one may be provided in the center. 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]

[0109] 1 ship 2 hull 3 Propulsion machine 3a Right propulsion machine (propulsion machine) 3b Left propulsion machine (propulsion machine) 8 Control Unit 20 Propulsion System 32 Power source 34 Promotion Department 45 Trim angle adjustment section 73 Trim angle control section V Ship speed θsp trim support angle θt trim angle θtd Lower limit of trim angle θts Trim angle reference value

Claims

1. A propulsion system provided on the hull has a drive source and a propulsion unit that generates thrust by power transmitted from the drive source, A trim angle adjustment unit for adjusting the trim angle of the propulsion unit 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 pitch tilt of the hull, a hump control is possible in which the trim angle of the propulsion system is adjusted by the trim angle adjustment unit, using a preset lower limit value for the trim angle. When stopping the execution of the hump control from the state in which the hump control is being performed, the trim angle of the propulsion system is adjusted by the trim angle adjustment unit according to the state of the hull. A ship's propulsion system.

2. The control unit, An acceleration trim angle adjustment mode is provided to adjust the trim angle when stopping the execution of the hump control from a state in which the hump control is being performed during the acceleration of the hull, The system includes a deceleration trim angle adjustment mode that adjusts the trim angle when the execution of the hump control is stopped while the hull is decelerating. The propulsion system for a ship according to claim 1.

3. The control unit, In the acceleration trim angle adjustment mode, if the trim angle of the propeller at the time the execution of the hump control is stopped is smaller than the trim angle reference value which is set to be larger than the lower limit of the trim angle and in the direction in which the propeller stands upright in the direction forward of the ship's propulsion, the trim angle of the propeller is adjusted so that the trim angle becomes the trim angle reference value. The propulsion system for a ship according to claim 2.

4. 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 the execution of the hump control is stopped while the trim support control and the hump control are being performed during the acceleration of the hull, the control to reduce the trim angle of the propulsion system by the trim support control is disabled in the acceleration trim angle adjustment mode. The propulsion system for a ship according to claim 3.

5. The control unit, In the deceleration trim angle adjustment mode, if the trim angle of the propeller at the time the execution of the hump control is stopped is smaller than the trim angle reference value which is set to be larger than the lower limit of the trim angle and in the direction in which the propeller stands upright in the direction forward of the ship's propulsion, the trim angle of the propeller is adjusted so that the trim angle becomes the trim angle reference value. The propulsion system for a ship according to claim 2.

6. 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 the hull is decelerating and the execution of the trim support control and the hump control is stopped, the deceleration trim angle adjustment mode allows the trim support control to reduce the trim angle of the propulsion system. The propulsion system for a ship according to claim 5.

7. The system further includes a trim angle control unit that operates the trim angle adjustment unit via external input, The control unit, The system includes a manual trim angle adjustment mode that is executed when the execution of the hump control is stopped by receiving an operation input from the trim angle control unit while the hump control is being performed. In the manual trim angle adjustment mode, if the trim angle of the propeller at the time the execution of the hump control is stopped is smaller than the trim angle reference value which is set to be larger than the lower limit of the trim angle and in the direction in which the propeller stands upright in the direction forward of the ship's propulsion, the trim angle of the propeller is adjusted so that the trim angle becomes the trim angle reference value. A ship propulsion system according to claim 1 or 2.

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