Control device, control method of control device, control program of control device

Abstract

A control device, a control method of a control device, and a control program of a control device. One of the objects of the present invention is to provide a technology of a control device capable of appropriately exerting an air lubrication effect of reducing frictional resistance. A control device (10) of a certain aspect includes a bubble control section (20) that controls an ejection mechanism (80) for ejecting bubbles toward water from an air outlet (84) provided in a hull (90) of a ship (1), and a propulsion control section (30) that controls a propulsion force of a propulsion mechanism (70) for propelling the hull (90). One of the propulsion control section (30) and the bubble control section (20) is controlled in accordance with control by the other.

Description

TECHNICAL FIELD

[0001] The present application relates to a control device, a control method of a control device, and a control program of a control device. BACKGROUND

[0002] A ship having an air lubrication mechanism that provides an air layer on a bottom of a hull is known. For example, a ship having an air lubrication mechanism that blows air from a bottom of a hull is described in Patent Literature 1. The ship has an air blowing device that blows air from the bottom of the hull and a suppression unit that suppresses a relative decrease in thickness of an air layer that covers a prescribed region of the bottom of the hull. The air blowing device is provided with air blowing ports in a central region, a port side region, and a starboard side region of the bottom of the hull.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2012-056328 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The present inventors have arrived at the following recognition with respect to an air lubrication mechanism that supplies air to a bottom of a hull. The air lubrication mechanism exerts an effect (hereinafter referred to as "air lubrication effect") of reducing frictional resistance (hereinafter, simply referred to as "frictional resistance") between water and a hull by spouting air bubbles to the bottom of the hull. By this air lubrication effect, it is possible to reduce the consumed energy of a propulsion mechanism (hereinafter, simply referred to as "propulsion mechanism") that propels the hull. However, the air lubrication mechanism consumes energy in order to spout air while operating, and thus if the air lubrication mechanism is continuously operated, there is a case where the consumed energy of the air lubrication mechanism exceeds the reduced energy in the propulsion mechanism. Therefore, in consideration of the balance between the consumed energy of the air lubrication mechanism and the energy reduced by the air lubrication effect, it is desirable to cause the air lubrication mechanism to act in a case where the air lubrication effect is properly exerted.

[0008] For example, it is considered to cause the air lubrication mechanism to start / stop by the judgment of an operator. However, in this case, it is not easy to perform because the judgment is complicated, and thus it is not necessarily possible to properly exert the air lubrication effect.

[0009] In addition, from the viewpoint of properly exerting the air lubrication effect, the ship described in Patent Literature 1 does not take sufficient countermeasures.

[0010] The present application was made in view of such problems, and one of the objects thereof is to provide a technology of a control device that can properly exert the air lubrication effect of reducing frictional resistance.

[0011] SOLUTION TO PROBLEM

[0012] To solve the above problem, a control device according to an aspect of the present application includes a bubble control section that controls an air bubble jetting mechanism for jetting air bubbles toward water from an air outlet provided in a hull of a ship, and a propulsion control section that controls a propulsion force of a propulsion mechanism for propelling the hull. One of the propulsion control section and the bubble control section is controlled in accordance with control of the other.

[0013] According to this aspect, the air bubble jetting mechanism and the propulsion mechanism can be controlled in a cooperative manner.

[0014] Another aspect of the present application is a control method of a control device. The method includes a step of controlling, by a control device that controls an air bubble jetting mechanism and a propulsion mechanism, one of the air bubble jetting mechanism and the propulsion mechanism in accordance with control of the other, wherein the air bubble jetting mechanism is for jetting air bubbles toward water from an air outlet provided in a hull of a ship, and the propulsion mechanism is for propelling the hull.

[0015] According to this aspect, the air bubble jetting mechanism and the propulsion mechanism can be controlled in a cooperative manner.

[0016] Still another aspect of the present application is a control program of a control device. The program causes a computer to execute a step of controlling, by a control device that controls an air bubble jetting mechanism and a propulsion mechanism, one of the air bubble jetting mechanism and the propulsion mechanism in accordance with control of the other, wherein the air bubble jetting mechanism is for jetting air bubbles toward water from an air outlet provided in a hull of a ship, and the propulsion mechanism is for propelling the hull.

[0017] According to this aspect, the air bubble jetting mechanism and the propulsion mechanism can be controlled in a cooperative manner.

[0018] Furthermore, any combination of the above, or a mode obtained by mutually replacing the constituent elements or aspects of the present application between a method, a device, a program, a transitory or non-transitory storage medium in which the program is recorded, and a system, and the like, is also effective as a mode of the present application.

[0019] Effects of the Invention

[0020] According to the present application, it is possible to provide a control device that can appropriately exert an air lubrication effect of reducing frictional resistance. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a diagram schematically showing a ship to which a control device according to the present application is applied.

[0022] Figure 2 is a block diagram schematically showing a control device according to a first embodiment of the present application.

[0023] Figure 3 It is shown Figure 2 A flowchart illustrating an example of the operation of a control device.

[0024] Figure 4 This is a block diagram that schematically illustrates the control device according to the second embodiment of the present invention.

[0025] Figure 5 It is shown Figure 4 A flowchart illustrating an example of the operation of a control device.

[0026] Figure 6 This is a block diagram that schematically illustrates the control device according to the third embodiment of the present invention.

[0027] Figure 7 It is shown Figure 6 A flowchart illustrating an example of the operation of a control device.

[0028] Figure 8 This is a block diagram that schematically illustrates the control device according to the fourth embodiment of the present invention.

[0029] Figure 9 It is shown Figure 8 A flowchart illustrating an example of the operation of a control device.

[0030] Figure 10 This is a block diagram that schematically illustrates the control device according to the fifth embodiment of the present invention.

[0031] Figure 11 It is shown Figure 10 A flowchart illustrating an example of the operation of a control device.

[0032] Figure 12 This is a block diagram that schematically illustrates the control device according to the sixth embodiment of the present invention.

[0033] Figure 13 It is shown Figure 12 A diagram showing an example of the control device's handle position and target speed.

[0034] Figure 14 It is shown Figure 12 A flowchart illustrating an example of the operation of a control device. Detailed Implementation

[0035] The present invention will now be described with reference to the accompanying drawings, based on preferred embodiments. In the embodiments and modifications, the same or equivalent constituent elements and components are labeled with the same reference numerals, and repeated descriptions are omitted where appropriate. Furthermore, for ease of understanding, the dimensions of the components in the drawings are shown in appropriate enlargements or reductions. Additionally, in the drawings, parts of components that are not important in describing the embodiments are omitted.

[0036] In addition, for each of the constituent elements having commonalities, "first, second, and the like" are added to the beginning of the name to distinguish them, and they are omitted when collectively referred to. In addition, the language including ordinal numbers such as first, second, and the like is used for the purpose of explaining a plurality of constituent elements, but the language is used only for the purpose of distinguishing one constituent element from other constituent elements, and the constituent element is not limited by the language.

[0037] In the present specification, a case where energy reduced by air lubrication exceeds energy required for air lubrication is referred to as "good" or "positive" in energy balance, and a case where energy required for air lubrication exceeds energy reduced by air lubrication is referred to as "poor" or "negative" in energy balance. In addition, in the case of good energy balance, it is expressed that the air lubrication effect is appropriately exerted. In addition, a case where energy balance is improved is expressed as "improved".

[0038] In the present specification, a ship speed of a hull with respect to water is simply referred to as "ship speed", and a current draft of the hull is simply referred to as "draft".

[0039] In the embodiments disclosed in the present specification, as for an object composed of a plurality of objects, the plurality of objects can be integrated, and conversely, an object composed of one object can be divided into a plurality of objects. Whether or not integrated, as long as it is configured to be able to achieve the object of the present invention.

[0040] In the embodiments disclosed in the present specification, as for a function in which a plurality of functions are dispersedly provided, a part or all of the plurality of functions can be centrally provided, and conversely, a function in which a plurality of functions are centrally provided can be provided so that a part or all of the plurality of functions are dispersed. Whether or not the function is centralized or dispersed, as long as it is configured to be able to achieve the object of the present invention.

[0041] [First Embodiment]

[0042] Next, a control device 10 according to a first embodiment of the present invention will be described with reference to the drawings. Figure 1 is a view schematically showing a ship 1 to which the control device 10 according to the present invention is applied. In the present embodiment, the ship 1 is provided with a hull 90, the control device 10, a propulsion mechanism 70, and an ejection mechanism 80. The propulsion mechanism 70 is a mechanism for generating a propulsive force for propelling the hull 90. The ejection mechanism 80 constitutes an air lubrication mechanism that generates an air lubrication effect of reducing a frictional resistance by ejecting air bubbles B from, for example, an air outlet 84 provided at a bottom 92 of the hull 90. Hereinafter, the ejection mechanism 80 when ejecting air is sometimes referred to as "ejection time", and the ejection mechanism 80 when not ejecting air is sometimes referred to as "non-ejection time".

[0043] Figure 2Fig. 1 is a block diagram schematically showing a control device 10 of the present embodiment. Figure 2 Each block shown in the block diagram and the like described later can be realized in hardware by elements such as a processor, a CPU, a memory of a computer, an electronic circuit, a mechanical device, and in software by a computer program and the like, but the functional blocks realized by cooperation of them are depicted here. Thus, it is understood by those skilled in the art that the functional blocks can be realized in various forms by a combination of hardware and software.

[0044] The control device 10 is provided with a bubble control section 20, a propulsion control section 30, an instruction receiving section 36, an overload prediction section 32, and a storage section 47. The bubble control section 20 controls an ejection mechanism 80 for ejecting bubbles B from an air outlet 84 provided in a bottom 92 of a hull 90. A propulsion mechanism 70 is used to generate a propulsion force for propelling the hull 90. The instruction receiving section 36 receives an instruction signal for instructing a magnitude of the propulsion force of the propulsion mechanism 70 and an actual signal indicating a magnitude of the current propulsion force. The propulsion control section 30 controls the propulsion force of the propulsion mechanism 70 based on a comparison result of the instruction signal and the actual signal received by the instruction receiving section 36. The storage section 47 stores each input information described later in chronological order, and stores each reference value and each threshold value described later. The overload prediction section 32 is described later.

[0045] In the control device 10, one of the propulsion control section 30 and the bubble control section 20 is controlled in accordance with the control of the other. According to this structure, since the ejection mechanism 80 and the propulsion mechanism 70 are controlled in a manner that they cooperate with each other, it is possible to improve the energy budget of the hull 90. In the present embodiment, the bubble control section 20 controls the ejection mechanism 80 in accordance with the control of the propulsion control section 30. In this case, it is possible to improve the energy budget by controlling the bubble control section 20 in accordance with the condition of the propulsion control section 30.

[0046] (Propulsion mechanism)

[0047] The propulsion mechanism 70 is only required to be able to propel the hull 90, and in the present embodiment, a diesel engine (hereinafter referred to as "main engine 74") is provided as a prime mover 79, and the main engine 74 is used to rotate a propeller 75 to obtain a propulsion force. The propulsion mechanism 70 consumes an amount of fuel corresponding to the rotation speed and the torque of the main engine 74 in order to operate the main engine 74. The propulsion mechanism 70 is provided with a speed governing device 77 for suppressing variation in the rotation speed of the main engine 74. The speed governing device 77 is also referred to as a speed governor, and adjusts the amount of fuel supply to moderate the variation in the rotation speed of the main engine 74 when the rotation speed of the main engine 74 is varied with respect to the load.

[0048] (Propulsion control section)

[0049] The propulsion control section 30 controls the main engine 74. The propulsion control section 30 of the present embodiment performs control to increase or decrease the rotation speed of the main engine 74, stop the main engine 74, and the like, based on an operation input of a manipulation device (hereinafter referred to as "remote controller 50") for remotely manipulating the main engine 74 provided at a bridge or the like of the ship 1. The remote controller 50 has an operation handle 51 as an operation section for instructing the magnitude of the propulsive force of the propulsion mechanism 70. The remote controller 50 transmits an instruction signal C1 for instructing the magnitude of the propulsive force to the control device 10 according to the position (hereinafter referred to as "handle position P") of the operation handle 51. The handle position P exemplifies the operation state of the operation section.

[0050] The operation handle 51 is not limited in its mode as long as the operator can input an operation to the manipulation device. For example, the operation handle 51 can have a movable operation section, or can not have a movable operation section. For example, the operation handle 51 can detect an instruction according to the touch position of a touch panel.

[0051] The control device 10 of the present embodiment has an instruction receiving section 36 that receives the instruction signal C1. The propulsion control section 30 changes the propulsive force of the propulsion mechanism 70 based on the instruction signal C1 received by the instruction receiving section 36. The operator can change the propulsive force of the propulsion mechanism 70 within a prescribed range including zero, forward, and reverse, by changing the position of the operation handle 51 of the remote controller 50.

[0052] (Ejection mechanism)

[0053] The ejection mechanism 80 is a mechanism that ejects bubbles B into water from an air outlet 84 provided at the bottom 92 during sailing. Since a portion of the bottom 92 is covered with an air layer formed by the bubbles B ejected from the air outlet 84, the frictional resistance of the hull 90 is reduced. The ejection mechanism 80 of the present embodiment has an engine 81 for driving a generator 82 and a compressor 83 driven by the electric power generated by the generator 82.

[0054] (Bubble control section)

[0055] The bubble control section 20 controls the ejection mechanism 80 to a state in which the engine 81, the generator 82, and the compressor 83 are operated to eject bubbles B and a state in which the engine 81 is stopped to not eject bubbles B. The ejection mechanism 80 consumes a prescribed amount of fuel in order to operate the engine 81 at the time of ejection.

[0056] It is desirable to smoothly accelerate and decelerate the hull. Therefore, the bubble control section 20 of the present embodiment increases the amount of emission of the bubbles B when the command signal Cl indicates acceleration. In the present specification, the case where the amount of emission of the bubbles B is increased includes the case where the emission of the bubbles B is started. In this case, by the increase in the bubbles B or the start of the emission of the bubbles B, the air lubrication effect is enhanced, so that the acceleration can be smoothly performed and the time to reach the target speed can be shortened. In addition, the bubble control section 20 decreases the amount of emission of the bubbles B when the command signal Cl indicates deceleration. In the present specification, the case where the amount of emission of the bubbles B is decreased includes the case where the emission of the bubbles B is stopped. In this case, by the decrease in the bubbles B or the stop of the emission of the bubbles B, the air lubrication effect is weakened, so that the time to reach the target speed can be shortened.

[0057] In the present embodiment, the propulsion mechanism 70 has the main engine 74 that rotates the propeller 75. The structure of the propeller 75 is not limited, and for example, it can be a fixed-pitch propeller or a variable-pitch propeller. The propeller 75 of the example is a variable-pitch propeller 72 that changes the blade angle W of the propeller blade 73 according to a blade angle command from the propulsion control section 30. The variable-pitch propeller 72 has a blade angle setting section 71 that changes the blade angle W according to the control of the propulsion control section 30. The blade angle setting section 71 detects the current actual blade angle (hereinafter referred to as "actual blade angle W2"), performs feedback control using the actual blade angle W2, and achieves the blade angle W according to a blade angle command (hereinafter referred to as "target blade angle Wl").

[0058] In the case of the variable-pitch propeller 72, the propulsion force of the propulsion mechanism 70 is changed by changing the blade angle W while causing the main engine 74 to operate at a fixed rotation speed. If the main engine 74 is operated at a rotation speed at which the fuel consumption is small, the fuel consumption amount of the main engine 74 can be saved.

[0059] In the propulsion control section 30 of the example, the relationship between the rotation speed command (hereinafter referred to as "target rotation speed Nl") of the main engine 74 corresponding to the handle position P of the operation handle 51 of the remote controller 50 and the blade angle command of the propeller blade 73 is set as a combinator curve in advance. Regarding the combinator curve, as an example, the relationship between each handle position P of the operation handle 51 and the target rotation speed Nl and the target blade angle Wl is defined in such a manner that the target rotation speed Nl = 80 rpm and the target blade angle Wl = 0 deg in the case where the handle position P is STOP, and the target rotation speed Nl = 120 rpm and the target blade angle Wl = 25 deg in the case where the handle position P is N / FMAX.

[0060] Further, the propulsion control section 30 is also provided with a control that causes the target blade angle Wl to be varied at a predetermined speed (hereinafter referred to as "CPP blade angle variation speed") even if the handle is operated sharply, to moderate the influence caused by a sharp change in the blade angle.

[0061] The propulsion mechanism 70 is provided with a limiter 60 that performs a limit control to protect the main engine 74. The limiter 60 can be provided with a limit mechanism based on various principles. In the present embodiment, the limiter 60 is provided with an ALC limiter 69 that performs a limit control to protect the main engine 74 from an overload. In a case where the current actual load (hereinafter referred to as "actual load") of the main engine 74 exceeds a predetermined target load, the ALC limiter 69 reduces the blade angle of the propeller blade 73.

[0062] The ALC limiter 69 of the present embodiment compares the target load and the actual load of the main engine 74, and in a case where the actual load is higher than the target load (hereinafter referred to as "overload state"), performs a control for reducing the blade angle of the propeller blade 73 (hereinafter referred to as "ALC (Automatic Load Control) control). The blade angle is reduced by the ALC control, thereby preventing the main engine 74 from being overloaded.

[0063] The overload prediction section 32 predicts whether the main engine 74 exceeds a prescribed load. In this example, the command signal is a signal for instructing the target rotation speed Nl of the main engine 74, and the actual signal is the actual rotation speed N2 as the current rotation speed (hereinafter referred to as "actual rotation speed N2") of the main engine 74. In the present embodiment, the overload prediction section 32 monitors the load of the main engine 74 in a load state before the ALC limiter 69 operates. In particular, the overload prediction section 32 predicts whether the main engine 74 exceeds a prescribed load, based on the target rotation speed Nl of the main engine 74, the actual rotation speed N2 of the main engine 74, and the current fuel input amount (hereinafter referred to as "fuel input amount S2") of the main engine 74.

[0064] In the present embodiment, the bubble control section 20 performs a control as follows based on the prediction result of the overload prediction section 32. In a case where it is predicted that a prescribed load is exceeded, the bubble control section 20 increases the ejection amount of the bubble B. That is, the overload prediction section 32 and the bubble control section 20 enhance the air lubrication effect in a load state before the ALC limiter 69 operates. In this case, it is possible to prevent the load of the main engine 74 from exceeding a prescribed load. Further, in a case where it is predicted that a prescribed load is not exceeded, the bubble control section 20 maintains the ejection state of the bubble B.

[0065] Next, an example in which the command signal is a target blade angle Wl of the variable pitch propeller 72 and the actual signal is an actual blade angle W2 of the variable pitch propeller 72 will be described. The overload prediction section 32 of the present embodiment also predicts whether the main engine 74 exceeds the prescribed load based on the target blade angle Wl and the actual blade angle W2 of the variable pitch propeller 72. In this case, it is possible to prevent the load of the main engine 74 from exceeding the prescribed load in a ship having the variable pitch propeller 72. For example, the overload prediction section 32 can predict the load condition of the main engine 74 from the combined curve. As a result, it is possible to reduce the case where the blade angle is decreased and the ship speed is reduced due to the ALC control of the ALC limiter 69.

[0066] It is desirable to have high prediction accuracy. Therefore, the overload prediction section 32 of the present embodiment can also predict whether the main engine 74 exceeds the prescribed load based on at least one of a target value of the speed at which the blade angle is changed and a target value of the speed at which the rotation speed of the main engine 74 is changed, which are set in advance. When the target value of the speed at which the blade angle is changed and the target value of the speed at which the rotation speed of the main engine 74 is changed are collectively referred to, it is sometimes called "change speed setting". In this case, it is possible to more accurately predict the case where the load of the main engine 74 exceeds the prescribed load.

[0067] For example, a target value of the speed at which the CPP blade angle is changed is set in advance, and the blade angle setting section 71 outputs the blade angle command in accordance with the target value. The overload prediction section 32 predicts whether the prescribed load of the main engine 74 is exceeded based on the target blade angle, the actual blade angle, and the target value of the speed at which the CPP blade angle is changed. As a result, it is possible to suppress the decrease in the blade angle and the reduction in the ship speed due to the ALC control of the ALC limiter 69. In another example, a target value of the speed at which the rotation speed of the main engine 74 is changed is set in advance, and the propulsion control section 30 outputs the rotation speed command in accordance with the target value. The overload prediction section 32 predicts whether the prescribed load of the main engine 74 is exceeded based on the target rotation speed Nl, the actual rotation speed N2, and the target value of the speed at which the rotation speed of the main engine 74 is changed.

[0068] By having the overload prediction section 32, it is possible to increase the amount of the bubble B to be emitted at an optimum timing, and it is possible to avoid the overload of the main engine 74 and thus smoothly increase the ship speed.

[0069] The operation S110 of the control device 10 of the present embodiment configured as described above will be described. Figure 3 is a flowchart showing the operation S110 of the control device 10.

[0070] When the operator operates the handle position P of the operation handle 51 of the remote controller 50 to the speed increase side, the propulsion control section 30 increases the target rotation speed Nl of the main engine 74 or increases the target blade angle Wl of the variable pitch propeller 72 in accordance with the combined curve. Thereby, the propulsion force of the propulsion mechanism 70 is increased, and the load of the main engine 74 is increased.

[0071] Here, when the operation S110 is started, the overload prediction section 32 predicts the load condition of the main engine 74 based on the combined curve (step Slll). In this step, the overload prediction section 32 predicts the load condition of the main engine 74 in accordance with the speed of change of the load caused by the CPP blade angle variable speed setting in addition to based on the combined curve.

[0072] The bubble control section 20 judges whether or not the load of the main engine 74 exceeds the prescribed load based on the prediction result of the overload prediction section 32 (step S112). In the case where it is judged that the load of the main engine 74 does not exceed the prescribed load (NO of step S112), the control device 10 ends the operation S110.

[0073] In the case where it is judged that the load of the main engine 74 exceeds the prescribed load (YES of step S112), the bubble control section 20 starts the emission of the bubbles B by the emission mechanism 80, and in the case where the emission mechanism 80 is already started, increases the emission amount of the bubbles B (step S113). As a result, by the action of the bubbles B, the air lubrication effect is increased, and the hull 90 is smoothly accelerated.

[0074] After step S113 is executed, S110 is ended. The above-described steps are only an example, and various modifications can be made.

[0075] The features of the control device 10 of the present embodiment are described. The control device 10 is provided with: a bubble control section 20 that controls an emission mechanism 80 for emitting bubbles toward water from an air outlet 84 provided to a hull 90 of a ship 1; and a propulsion control section 30 that controls a propulsion force of a propulsion mechanism 70 for propelling the hull 90. One of the propulsion control section 30 and the bubble control section 20 is controlled in accordance with the control of the other.

[0076] According to this structure, the emission mechanism 80 and the propulsion mechanism 70 are controlled in a manner that they cooperate, and thus the air lubrication effect can be appropriately exerted.

[0077] In the present embodiment, the bubble control section 20 controls the emission mechanism 80 in accordance with the control of the propulsion control section 30. In this case, the air lubrication effect can be exerted at an appropriate time in accordance with the control of the propulsion control section 30.

[0078] This embodiment includes a command receiving unit 36 ​​that receives a command signal and a real-time signal. The command signal indicates the magnitude of the propulsion force of the propulsion mechanism 70, and the real-time signal indicates the current magnitude of the propulsion force. In this embodiment, the propulsion control unit 30 controls the propulsion force of the propulsion mechanism 70 based on a comparison between the command signal and the real-time signal. The bubble control unit 20 increases the amount of bubbles ejected when the command signal indicates acceleration, and decreases the amount of bubbles ejected when the command signal indicates deceleration. In this case, the time to reach the target speed can be shortened.

[0079] In this embodiment, the propulsion mechanism 70 includes a main unit 74 that rotates the propeller 75. The command signal is a signal indicating the target rotational speed N1 of the main unit, and the actual signal is the actual rotational speed N2, which is the current rotational speed of the main unit. This embodiment includes an overload prediction unit 32, which predicts whether the load on the main unit 74 exceeds a predetermined load based on the target rotational speed of the main unit 74, the actual rotational speed of the main unit 74, and the current fuel input of the main unit 74. If the overload prediction unit 32 predicts that the load exceeds the predetermined load, the bubble control unit 20 increases the amount of bubbles ejected. In this case, the load on the main unit 74 can be suppressed to below the predetermined load.

[0080] In this embodiment, the propeller 75 is a variable-pitch propeller 72 capable of changing the blade angle of the propeller blades 73. The command signal is the target blade angle W1 of the variable-pitch propeller 72, and the actual signal is the actual blade angle W2, which is the current blade angle of the variable-pitch propeller 72. Furthermore, the overload prediction unit 32 predicts whether the load on the main engine 74 exceeds a predetermined load based on the target blade angle and the actual blade angle of the variable-pitch propeller 72. As a result, with the variable-pitch propeller 72, the load on the main engine 74 can be suppressed to below a predetermined load.

[0081] In this embodiment, the overload prediction unit 32 further predicts whether the load on the main unit 74 exceeds a predetermined load based on at least one of the target value of the speed at which the blade angle changes from the actual blade angle to the target blade angle and the target value of the speed at which the main unit's rotational speed changes from the actual rotational speed to the target rotational speed. In this case, the prediction accuracy of the load on the main unit 74 can be improved.

[0082] The above is a description of the first embodiment.

[0083] The second to eighth embodiments of the present invention will now be described. In the accompanying drawings and descriptions of the second to eighth embodiments, the same reference numerals are used to denote the same or equivalent constituent elements and components as in the first embodiment. Descriptions that are repeated in the first embodiment are omitted where appropriate, and the focus is on describing structures that differ from the first embodiment.

[0084] [Second Embodiment]

[0085] Referring to Figure 4 , Figure 5 a control device 10 according to a second embodiment of the present application will be described. Figure 4 is a block diagram schematically showing the control device 10 of the present embodiment. The control device 10 of the present embodiment is provided with a bubble control section 20, a propulsion control section 30, an instruction receiving section 36, a shift judgment section 35, and a storage section 47. The present embodiment differs from the first embodiment in that the shift judgment section 35 is provided, and thus the shift judgment section 35 will be mainly described.

[0086] A torsional vibration stress is applied to the propulsion shaft 78 that transmits the rotation of the prime mover 79 (in this example, the main engine 74) to the propeller 75. The torsional stress generated on the propulsion shaft 78 varies in synchronization with the rotation of the main engine 74, and the propulsion shaft 78 has an inherent vibration frequency in each vibration mode. Therefore, if the rotation of the main engine 74 coincides with the inherent vibration frequency of the propulsion shaft 78, the torsional stress increases, and thus it is possible to exceed the allowable range of the propulsion shaft 78. Therefore, in the present embodiment, a rotation speed range of the main engine 74 in which the torsional stress of the propulsion shaft 78 increases (hereinafter, referred to as "barred range") is set in advance, and the control device 10 performs control so as to shorten the barred range passing time at acceleration. In particular, when accelerating from low speed and being below the barred range, the control device 10 causes the ejection mechanism 80 to be activated and the ejection amount of the bubble B to be increased by the bubble control section 20. As a result, the air lubrication effect is improved and the hull 90 is smoothly accelerated, and thus it is possible to shorten the barred range passing time.

[0087] When the current actual rotation speed N2 of the main engine 74 is outside the barred range, the shift judgment section 35 judges whether a shift instruction (hereinafter, referred to as "shift instruction") into the barred range is received. In particular, the shift instruction is an instruction for shifting from the actual rotation speed N2 to a target rotation speed N1 different from the actual rotation speed N2 by passing the barred range. In a case where the shift judgment section 35 judges that the shift instruction is received, the bubble control section 20 increases the ejection amount of the bubble B. In this case, it is possible to shorten the passing time of the barred range. In the present embodiment, the shift judgment section 35 judges whether the shift instruction is received based on the handle position P of the remote controller 50. In this case, it is possible to perform the shift judgment more in advance.

[0088] The operation S120 of the control device 10 of the present embodiment configured as described above will be described. Figure 5 is a flowchart showing the operation S120 of the control device 10.

[0089] When the operation S120 is started, the shift judging section 35 acquires the current actual rotation speed N2, and judges whether the actual rotation speed N2 is outside the forbidden zone (step S121). In the case where the actual rotation speed N2 is not outside the forbidden zone (NO in step S121), the control device 10 ends the operation S120.

[0090] In the case where the actual rotation speed N2 is outside the forbidden zone (YES in step S121), the control device 10 acquires the handle position P via the command receiving section 36 (step S122). After step S122 is executed, the shift judging section 35 determines the target rotation speed Nl based on the acquired handle position P, and judges whether a shift command into the forbidden zone is received (step S123). In the case where the shift command is not received (NO in step S123), the control device 10 ends the operation S120.

[0091] In the case where it is judged that the shift command is received (YES in step S123), the bubble control section 20 increases the ejection amount of the bubbles B (step S124). In this step, the ejection mechanism 80 is started to eject the bubbles B when the ejection mechanism 80 is not started, and the ejection amount of the bubbles B is increased when the ejection mechanism 80 is already started.

[0092] After step S124 is executed, the operation S120 ends. The above-described steps are only an example, and various modifications can be made.

[0093] When the ship 1 is decelerated, the deceleration takes time in a state where the frictional resistance is low in a state where the bubbles B are ejected, and thus the forbidden zone passing time becomes long. Therefore, the control device 10 of the present embodiment controls to decrease the ejection amount of the bubbles B in the case where the current actual rotation speed N2 of the main engine 74 is above the forbidden zone and a deceleration command is received which targets a lower speed than the forbidden zone. In this case, by decreasing the ejection amount of the bubbles B, the frictional resistance can be increased to decelerate smoothly, and thus the forbidden zone passing time can be shortened.

[0094] The features of the control device 10 of the present embodiment will be described. In the present embodiment, the propulsion mechanism 70 has a prime mover 79 which rotates the propeller 75. In addition, the present embodiment is provided with a shift judging section 35 which judges whether a shift command into the forbidden zone is received when the current actual rotation speed of the prime mover 79 is outside a pre-set rotation speed range (forbidden zone). In the case where the shift judging section 35 judges that the shift command into the forbidden zone is received, the bubble control section 20 increases the ejection amount of the bubbles. In this case, the passing time of the forbidden zone can be shortened.

[0095] In the present embodiment, the shift determination section 35 determines whether or not a shift instruction to enter the forbidden zone is received, based on an operation state of the operation section of the remote manipulation prime mover 79. In this case, the shift determination can be performed more in advance.

[0096] The above is a description of the second embodiment.

[0097] [Third Embodiment]

[0098] A control device 10 according to a third embodiment of the present application will be described with reference to Figure 6 Figure 7 The control device 10 according to the third embodiment of the present application will be described with reference to Figure 6 is a block diagram schematically showing the control device 10 according to the present embodiment. The control device 10 according to the present embodiment is provided with a bubble control section 20, a propulsion control section 30, an instruction reception section 36, a position determination section 33, an acceleration / deceleration determination section 34, and a storage section 47. The present embodiment differs from the first embodiment in that the position determination section 33 and the acceleration / deceleration determination section 34 are provided. Therefore, the position determination section 33 and the acceleration / deceleration determination section 34 will be mainly described.

[0099] The acceleration / deceleration determination section 34 determines whether or not the ship body 90 is accelerated or decelerated, based on at least one of the fuel injection amount injected into the main engine 74 and the actual rotation speed. The bubble control section 20 performs at least one of a first action of increasing the ejection amount of the bubble B when the acceleration / deceleration determination section 34 determines acceleration and a second action of decreasing the ejection amount of the bubble B when the acceleration / deceleration determination section 34 determines deceleration. In this case, the time to reach the target speed can be shortened.

[0100] In a harbor, the ship 1 is mostly navigated at low speed. In navigation at low speed, the air lubrication effect becomes small, and thus the air lubrication effect of the ejection mechanism 80 with respect to the fuel consumption amount becomes small, and the efficiency is not high. Therefore, the control device 10 according to the present embodiment controls so as to decrease the ejection amount of the bubble B when the ship 1 is located in the harbor.

[0101] In the present embodiment, the position determination section 33 determines whether or not the ship 1 is located in the harbor, based on a position signal indicating the position of the ship 1. When the position determination section 33 determines that the ship 1 is located outside the harbor (not in the harbor), the bubble control section 20 increases the ejection amount of the bubble B. In this case, smooth acceleration can be performed outside the harbor. In addition, when the position determination section 33 determines that the ship 1 is located in the harbor, the bubble control section 20 decreases the ejection amount of the bubble B. In this case, the use of the air lubrication with low effect in the harbor can be avoided, and the energy efficiency can be improved.

[0102] ​The position determining section 33 can determine whether or not the ship 1 is located within the harbor based on the handle position P of the remote controller 50. For example, when the handle position P is a position of an operation toward outside of the harbor area (hereinafter, referred to as "sea area"), the position determining section 33 can determine that the ship 1 is located within the harbor. In addition, the position determining section 33 can acquire the position of the ship 1 by a publicly known positioning system. As such a positioning system, there are a satellite positioning system such as a GPS (Global Positioning System), a positioning system using a gyro sensor, and the like.

[0103] The operation S130 of the control device 10 of the present embodiment configured as above will be described. Figure 7 is a flowchart showing the operation S130 of the control device 10.

[0104] When the operation S130 is started, the position determining section 33 determines whether or not the ship 1 is located within the harbor based on a position signal indicating the position of the ship 1 (step S131). In a case where it is determined that the ship 1 is located within the harbor (YES in step S131), the control device 10 reduces the amount of emission of the bubble B (step S136). After step S136 is executed, the operation S130 ends.

[0105] In a case where it is determined that the ship 1 is not located within the harbor (is located outside the harbor) (NO in step S131), the acceleration / deceleration determining section 34 determines whether or not to accelerate the ship body 90 based on information J1 of at least one of the fuel input amount S2 input to the main engine 74 and the actual rotation speed N2 (step S132).

[0106] In a case where the acceleration / deceleration determining section 34 determines to accelerate the ship body 90 (YES in step S132), the bubble controlling section 20 increases the amount of emission of the bubble B (step S133). In this step, when the emission mechanism 80 is not activated, the emission mechanism 80 is activated to emit the bubble B, and when the emission mechanism 80 is already activated, the amount of emission of the bubble B is increased. After step S133 is executed, S130 ends.

[0107] In a case where the acceleration / deceleration determining section 34 determines not to accelerate the ship body 90 (NO in step S132), the acceleration / deceleration determining section 34 determines whether or not to decelerate the ship body 90 based on the information J1 (step S134). In a case where the acceleration / deceleration determining section 34 determines not to decelerate the ship body 90 (NO in step S134), the operation S130 ends.

[0108] In a case where the acceleration / deceleration judging section 34 judges to decelerate the hull 90 (YES in step S134), the control device 10 reduces the amount of ejection of the bubbles B (step S135). After step S135 is executed, the operation S130 ends. The above-described steps are only an example, and various modifications can be made.

[0109] The features of the control device 10 of the present embodiment will be described. In the present embodiment, the propulsion mechanism 70 has a main engine 74 that rotates the propeller 75. In addition, the present embodiment is provided with an acceleration / deceleration judging section 34 that judges whether to accelerate or decelerate the hull 90 based on at least one of the fuel injection amount injected into the main engine 74 and the actual rotation speed. The bubble control section 20 executes at least one of a first operation of increasing the amount of ejection of the bubbles in a case where the acceleration / deceleration judging section 34 judges to accelerate and a second operation of reducing the amount of ejection of the bubbles in a case where the acceleration / deceleration judging section 34 judges to decelerate. In this case, it is possible to shorten the time to reach the target speed.

[0110] The present embodiment is provided with a position judging section 33 that acquires a position signal indicating the position of the ship 1 and judges whether the ship 1 is located inside a harbor based on the position signal. In a case where the position judging section 33 judges that the ship 1 is located inside the harbor, the bubble control section 20 reduces the amount of ejection of the bubbles. In this case, it is possible to avoid using the air lubrication with low effectiveness inside the harbor and to improve the energy efficiency.

[0111] The above is a description of the third embodiment.

[0112] [Fourth Embodiment]

[0113] Reference Figure 8 , Figure 9 The control device 10 according to the fourth embodiment of the present application will be described. Figure 8 is a block diagram that schematically shows the control device 10 of the present embodiment. The control device 10 of the present embodiment is provided with a bubble control section 20, a propulsion control section 30, an instruction receiving section 36, a load prediction section 37, and a storage section 47. The present embodiment differs from the first embodiment in that the load prediction section 37 is provided, and thus the load prediction section 37 will be mainly described.

[0114] If the load of the main engine 74 becomes large and exceeds the load (hereinafter referred to as "predetermined load Fl") set in advance to the main engine 74 during the voyage (hereinafter referred to as "high load state") for a long time, the fuel consumption and the fuel cost during the voyage increase, and the energy saving becomes poor. In other words, it is also related to the reduction of the fuel cost during the voyage and the extension of the life of the main engine 74 to suppress the high load state of the main engine 74 during the voyage for a short period. The deterioration state of the main engine 74, the fuel consumption, and the like can be set as parameters, and the predetermined load Fl in this case can be set by a voyage experiment or the like.

[0115] The high load state of the main engine 74 when unintended acceleration occurs based on the acceleration command from the remote controller 50 or the like depending on the condition of the sea and the state of the main engine 74. In addition, if the load of the main engine 74 exceeds the predetermined load Fl, the fuel input amount of the main engine 74 sometimes increases sharply.

[0116] It is possible to cause the ejection mechanism 80 to act to reduce the load of the main engine 74 after the high load state occurs. However, the ejection mechanism 80 starts the engine 81, the generator 82, and the compressor 83 upon receiving the start command, and it takes a fixed time (hereinafter referred to as "start-up time") until the bubble B covers the bottom 92 of the ship in a predetermined state. Therefore, it is desirable to perform the load state determination of the main engine 74 before the above-mentioned high load state occurs, and to send a signal of start preparation to the ejection mechanism 80 to perform the bubble generation preparation action. Therefore, the present embodiment monitors the load of the main engine 74 by the load prediction section 37, and sends a start preparation command before the main engine 74 exceeds the predetermined load Fl, to cause the ejection mechanism 80 to perform the bubble generation preparation action.

[0117] By performing the generation preparation action, it is possible to promptly discharge the bubble B from the ejection mechanism 80 after the acceleration command, and to suppress the high load state at the time of acceleration by the air lubrication effect. As the generation preparation action, there are, for example, the operation confirmation of each element of the engine 81, the generator 82, the compressor 83, the idle operation of each element, the pressure confirmation of the air for bubble injection, the driving of the compressor to supplement the compressed air to the tank in the case where the pressure is less than a threshold value, and the like.

[0118] In the present embodiment, the load prediction section 37 predicts whether the main engine 74 exceeds the predetermined load Fl based on the fuel input amount S2 currently input to the main engine 74 and the actual rotation speed N2 of the main engine 74. For example, the fuel input amount S2 can be acquired from the governor 77. The governor 77 of this example is provided with a rack gear (not shown), and is configured to supply the main engine 74 with the amount of fuel corresponding to the rack position, so that the fuel input amount S2 can be determined based on the rack position.

[0119] For example, the load prediction section 37 can compare the acquired fuel injection amount S2 and the actual rotational speed N2 with reference values set in advance for them, and predict whether the load of the main engine 74 exceeds the prescribed load Fl based on the comparison result. Specifically, reference values of the fuel injection amount corresponding to each rotational speed from the low-speed side rotational speed to the high-speed side rotational speed in the use range are set for the main engine 74, and the reference values are stored in the storage section 47. The load prediction section 37 acquires the reference value of the fuel injection amount corresponding to the actual rotational speed N2 from the storage information of the storage section 47, and predicts that the main engine 74 exceeds the prescribed load Fl in a case where the deviation of the fuel injection amount S2 from the acquired reference value exceeds a threshold value.

[0120] The above-described reference values of the fuel injection amount for each rotational speed can be set in advance, or can be reference values obtained using a machine learning model generated through learning. As an example, the machine learning model can be generated by performing machine learning (supervised learning) in which information related to the actual rotational speed N2 of the main engine 74, the rack position of the speed adjusting device 77, and the handle position P of the remote controller 50 is input, and the variation of the load of the main engine 74 is output, in a sea trial or a voyage of the ship.

[0121] In addition, the machine learning model can also be generated by applying parameters at the time of operation of the main engine 74 in a calculation formula of the output of the main engine 74 and the load of the main engine 74. In this case, it is possible to make reference values that more reflect the characteristics of the main engine 74, and it is possible to improve the prediction accuracy of the load prediction section 37.

[0122] In addition, the load prediction section 37 can also predict whether the main engine 74 exceeds the prescribed load Fl by performing table processing on the acquired fuel injection amount S2 and the actual rotational speed N2 using a table made in advance.

[0123] In a case where the load prediction section 37 predicts that the load of the main engine 74 exceeds the prescribed load Fl, the bubble control section 20 causes the ejection mechanism 80 to perform the generation preparation operation of the bubble B. In this case, it is possible to suppress a sharp increase in the fuel injection amount in a case where the prescribed load Fl is exceeded.

[0124] The prediction accuracy of the load prediction section 37 can decrease depending on the state of an interference (hereinafter, simply referred to as "interference") that is a prescribed factor that affects at least one of the propulsion speed and the propulsion direction of the ship 1. For example, as the interference to the ship body 90, there are a tidal current (hereinafter, simply referred to as "tidal current") at the water area in which the ship 1 is sailing, a wind, a predetermined route (hereinafter, simply referred to as "route") in which the ship 1 is sailing, a draft of the ship body, the target rotation speed Nl, the target fuel input amount S l, and the like. Therefore, the load prediction section 37 of the present embodiment predicts whether the engine 74 exceeds the prescribed load Fl based on at least one of the tidal current, the wind, the route, the draft of the ship body, the target rotation speed Nl, and the target fuel input amount S l. In this case, the prediction accuracy of whether the engine 74 exceeds the prescribed load Fl can be improved. The state of these interferences is visually determined by the operator and input to the control device 10.

[0125] The operation S140 of the control device 10 of the present embodiment configured as described above will be described. Figure 9 is a flowchart showing the operation S140 of the control device 10.

[0126] When the operation S140 is started, the load prediction section 37 acquires the fuel input amount S2 and the actual rotation speed N2 (step S141). The load prediction section 37 predicts whether the engine 74 exceeds the prescribed load Fl based on the acquired fuel input amount S2 and actual rotation speed N2 (step S142). In this step, the load prediction section 37 also predicts whether the engine 74 exceeds the prescribed load Fl based on at least one of the tidal current, the wind, the route, the draft of the ship body, the target rotation speed Nl, and the target fuel input amount S l.

[0127] In a case where the load prediction section 37 predicts that the engine 74 does not exceed the prescribed load Fl (NO of step S142), the control device 10 ends the operation S140. In a case where the load prediction section 37 predicts that the engine 74 exceeds the prescribed load Fl (YES of step S142), the bubble control section 20 performs a generation preparation operation of the bubble B (step S143). After step S143 is performed, S140 ends. Each of the above steps is merely an example, and various modifications can be made.

[0128] The features of the control device 10 of the present embodiment will be described. In the present embodiment, the propulsion mechanism 70 has a main engine 74 that rotates a propeller 75. In addition, the present embodiment is provided with a load prediction section 37 that predicts whether the load of the main engine 74 exceeds a prescribed load based on the amount of fuel currently being fed to the main engine 74 and the actual rotation speed of the main engine 74. In the case where the load prediction section 37 predicts that the load of the main engine 74 exceeds the prescribed load, the bubble control section 20 causes the ejection mechanism 80 to perform a bubble generation preparation operation. In this case, it is possible to suppress a sharp increase in the amount of fuel being fed in the case where the prescribed load is exceeded.

[0129] The load prediction section 37 also predicts whether the load of the main engine 74 exceeds the prescribed load based on at least one of the tidal current, the wind, the predetermined route on which the ship 1 is traveling, the draft of the ship body, the target rotation speed, and the target amount of fuel being fed at the water area in which the ship 1 is traveling. In this case, it is possible to improve the prediction accuracy of whether the prescribed load is exceeded.

[0130] The above is a description of the fourth embodiment.

[0131] [Fifth Embodiment]

[0132] Reference Figure 10 , Figure 11 The control device 10 of the fifth embodiment of the present invention will be described. Figure 10 is a block diagram that schematically shows the control device 10 of the present embodiment. The control device 10 of the present embodiment is provided with a bubble control section 20, a propulsion control section 30, an instruction reception section 36, a restriction signal reception section 38, a release signal reception section 39, a period determination section 31, and a storage section 47. The present embodiment differs from the first embodiment in that it is provided with the restriction signal reception section 38, the release signal reception section 39, and the period determination section 31. Thus, the restriction signal reception section 38, the release signal reception section 39, and the period determination section 31 will be mainly described.

[0133] As described above, the propulsion mechanism 70 is provided with the limiter 60 to prevent an overload state of the main engine 74. However, depending on the state of the ship body 90 or the state of the disturbance, there are cases where it should be avoided for the limiter 60 to operate and fuel should be fed after the threshold of the limiter 60 is exceeded. Thus, the present embodiment, in the case where the load of the main engine 74 exceeds the prescribed load, increases the amount of ejection of the bubble B to avoid or mitigate the operation of the limiter 60 by the air lubrication effect.

[0134] In the present embodiment, the limiter 60 includes a torque limiter 67, a scavenge pressure limiter 68, and an ALC limiter 69. The torque limiter 67 detects the torque of the main engine 74, and in a case where the detection result thereof exceeds a threshold value Tl of the torque set in advance, limits the fuel injection amount to the main engine 74 to suppress the rise of the load of the main engine 74. The scavenge pressure limiter 68 detects the scavenge pressure of the main engine 74, and in a case where the detection result thereof exceeds a threshold value T2 of the scavenge pressure set in advance, limits the fuel injection amount to suppress the rise of the load of the main engine 74. The ALC limiter 69 compares the target load of the main engine 74 with the actual load, and in a case of an overload state in which the actual load is higher than the target load, reduces the blade angle of the propeller blade 73 to suppress the rise of the load of the main engine 74.

[0135] In the present embodiment, the torque limiter 67 generates a first limit signal Ll and supplies it to the control device 10 in a case where the torque of the main engine 74 exceeds the threshold value Tl, and generates a first limit release signal Ql and supplies it to the control device 10 in a case where the torque of the main engine 74 is equal to or lower than the threshold value Tl. In addition, the scavenge pressure limiter 68 generates a second limit signal L2 and supplies it to the control device 10 in a case where the scavenge pressure of the main engine 74 exceeds the threshold value T2, and generates a second limit release signal Q2 and supplies it to the control device 10 in a case where the scavenge pressure of the main engine 74 is equal to or lower than the threshold value T2. In addition, the ALC limiter 69 generates a third limit signal L3 and supplies it to the control device 10 in a case where the actual load is higher than the target load, and generates a third limit release signal Q3 and supplies it to the control device 10 in a case where the actual load is equal to or lower than the target load.

[0136] In a case of collectively referring to the first limit signal Ll, the second limit signal L2, and the third limit signal L3, they are simply referred to as "limit signals", and in a case of collectively referring to the first limit release signal Ql, the second limit release signal Q2, and the third limit release signal Q3, they are simply referred to as "limit release signals".

[0137] The limit signal receiving section 38 is configured to receive a limit signal indicating that the load of the main engine 74 exceeds a prescribed load. In a case where the limit signal is received, the bubble control section 20 increases the ejection amount of the bubble B. In this case, it is possible to smoothly achieve the speed-up or maintain the speed at the time of disturbance. In particular, in a case where the limit signal receiving section 38 receives at least one of the first limit signal Ll, the second limit signal L2, and the third limit signal L3, the bubble control section 20 increases the ejection amount of the bubble B.

[0138] The release signal receiving section 39 receives a restriction release signal. The bubble control section 20 reduces the amount of ejection of the bubble B in a case where the release signal is received. In the present embodiment, the amount of ejection of the bubble B is reduced in a case where a prescribed release condition including that the release signal receiving section 39 receives the restriction release signal is satisfied. In this case, by reducing the amount of ejection of the bubble B, the fuel consumption amount of the ejection mechanism 80 can be reduced. In particular, in a case where the first restriction release signal Q1, the second restriction release signal Q2, and the third restriction release signal Q3 are received by the release signal receiving section 39, the bubble control section 20 reduces the amount of ejection of the bubble B.

[0139] The prescribed release condition is not particularly limited as long as it is a condition related to the state of the disturbance and the load state of the main engine 74. In the present embodiment, the prescribed release condition includes that the actual rotation speed N2 of the main engine 74 reaches the target rotation speed N1. If the actual rotation speed N2 reaches the target rotation speed N1, the ship speed can be maintained, and thus the amount of ejection of the bubble B can be reduced to reduce the fuel consumption amount of the ejection mechanism 80.

[0140] If the period (hereinafter referred to as "ON / OFF period") between ON and OFF of the ejection mechanism 80 is short, deterioration can be caused. Therefore, the bubble control section 20 of the present embodiment reduces the amount of ejection of the bubble B after a prescribed standby period elapses from when the restriction release signal is received. In this case, the ON / OFF period of the ejection mechanism 80 can be extended.

[0141] As described above, sometimes a disturbance as a prescribed factor that causes an influence on at least one of the propulsion speed and the propulsion direction of the ship 1 is received. In the present embodiment, in a case where the magnitude of the disturbance at the point of time when the restriction release signal is received (hereinafter referred to as "second disturbance data G2") is larger than the magnitude of the disturbance at the point of time when the restriction signal is received (hereinafter referred to as "first disturbance data G1"), it is desirable to extend the standby period. Conversely, in a case where the second disturbance data G2 at the point of time when the restriction release signal is received is smaller than the first disturbance data G1 at the point of time when the restriction signal is received, the standby period can be shortened. Therefore, the control device 10 of the present embodiment further has a period determining section 31 that determines the standby period based on the first disturbance data G1 at the point of time when the restriction signal is received and the second disturbance data G2 at the point of time when the restriction release signal is received. The standby period can be set through experiments. When the first disturbance data G1 and the second disturbance data G2 are collectively referred to, the disturbance data is simply referred to.

[0142] Not limited to this interference, as an example, there are listed tidal current, wind, shipping route, draft, and the like as the interference. The first interference data G1 and the second interference data G2 in the present embodiment are visually determined by the operator and input to the control device 10. The period decision section 31 stores the first interference data G1 at the time point at which the restriction signal is received and the second interference data G2 at the time point at which the restriction cancellation signal is received in the storage section 47 on the basis of the input interference data. The period decision section 31 decides the standby period on the basis of the stored first interference data G1 and second interference data G2.

[0143] From the viewpoint of extending the ON / OFF period of the spouting mechanism 80, the bubble control section 20 of the present embodiment increases the spouting amount of the bubble B after a prescribed waiting start period elapses from the reception of the restriction signal. The waiting start period can be set through experiments.

[0144] As described above, the restriction signal of the present embodiment includes the first restriction signal L1 or the second restriction signal L2.

[0145] As described above, the control device 10 of the present embodiment controls the propulsion mechanism 70 having the variable pitch propeller 72. Therefore, the restriction signal of the present embodiment also includes the third restriction signal L3. Further, in the case where the control device controls the propulsion mechanism not having the variable pitch propeller, the restriction signal does not include the third restriction signal L3.

[0146] The operation S150 of the control device 10 of the present embodiment configured as above will be described. Figure 11 is a flowchart showing the operation S150 of the control device 10.

[0147] When the operation S150 is started, the control device 10 judges whether or not the restriction signal reception section 38 receives the restriction signal (step S151). In the case where the restriction signal is not received (NO of step S151), the control device 10 ends the operation S150.

[0148] In the case where the restriction signal is received (YES of step S151), the control device 10 acquires the first interference data G1 from the interference sensor 53 (step S152). In this step, the control device 10 stores the first interference data G1.

[0149] After step S152 is executed, the bubble control section 20 increases the spouting amount of the bubble B (step S153).

[0150] After step S153 is executed, the control device 10 determines whether the release signal receiving section 39 receives the restriction release signal (step S154). In a case where the restriction release signal is not received (NO in step S154), the control device 10 returns the process to the beginning of step S154, and repeats step S154.

[0151] In a case where the restriction release signal is received (YES in step S154), the control device 10 acquires the second disturbance data G2 from the disturbance sensor 53 (step S155). In this step, the control device 10 stores the second disturbance data G2 in the storage section 47.

[0152] After step S155 is executed, the period determining section 31 determines the standby period based on the first disturbance data G1 and the second disturbance data G2 (step S156).

[0153] After step S156 is executed, the control device 10 determines whether the standby period has elapsed (step S157). In a case where the standby period has not elapsed (NO in step S157), the control device 10 returns the process to the beginning of step S157, and repeats step S157.

[0154] In a case where the standby period has elapsed (YES in step S157), the bubble control section 20 reduces the ejection amount of the bubble B (step S158). After step S158 is executed, S150 ends. The above-described steps are merely examples, and various modifications can be made.

[0155] The features of the control device 10 of the present embodiment will be described. In the present embodiment, the propulsion mechanism 70 has the main engine 74 that rotates the propeller 75. In addition, the present embodiment is provided with the restriction signal receiving section 38 for receiving the restriction signal indicating that the load of the main engine 74 exceeds the prescribed load. In a case where the restriction signal receiving section 38 receives the restriction signal, the bubble control section 20 increases the ejection amount of the bubble. In this case, it is possible to avoid or mitigate the action of the limiter, and thus smoothly achieve the speed-up or maintain the speed at the time of disturbance.

[0156] In the present embodiment, the release signal receiving section 39 for receiving the restriction release signal indicating that the load of the main engine 74 is the prescribed load or less is provided, and in a case where the release condition including the reception of the restriction release signal by the release signal receiving section 39 is satisfied, the bubble control section 20 reduces the ejection amount of the bubble. In this case, it is possible to reduce the energy consumption amount (fuel consumption amount) of the ejection mechanism 80.

[0157] In the present embodiment, the prescribed cancellation condition includes the actual rotation speed of the main engine 74 reaching the target rotation speed. In this case, it is possible to reduce the energy consumption amount of the ejection mechanism 80 in the case where the target rotation speed is reached.

[0158] In the present embodiment, the prescribed cancellation condition includes a prescribed standby period elapsing from when the restriction signal is received. In this case, it is possible to avoid the ON / OFF period from being excessively shortened.

[0159] In the present embodiment, there is also a period determining section 31 that determines the standby period based on first disturbance data that is disturbance data of the point in time when the restriction signal is received and second disturbance data that is disturbance data of the point in time when the restriction cancellation signal is received, where the disturbance data is the magnitude of disturbance that is a prescribed factor that has an influence on at least one of the propulsion speed and the propulsion direction of the ship 1. In this case, it is possible to shorten the standby period to reduce the energy consumption amount of the ejection mechanism 80 in the case where the disturbance is small.

[0160] In the present embodiment, the restriction signal includes a restriction signal generated by the torque limiter in the case where the torque of the main engine 74 exceeds a threshold value and a restriction signal generated by the scavenge pressure limiter in the case where the scavenge pressure of the main engine 74 exceeds a threshold value. In this case, it is also possible to smoothly achieve the speed increase or maintain the speed at the time of disturbance in the case where the torque limiter and the scavenge pressure limiter are operating.

[0161] In the present embodiment, the propeller 75 is a variable pitch propeller 72 that is capable of changing the pitch angle of the propeller blades 73, the propulsion mechanism 70 has an ALC limiter that reduces the output of the main engine 74 in the case where the actual load is higher than the target load, and the restriction signal includes a restriction signal generated by the ALC limiter in the case where the actual load is higher than the target load. In this case, it is also possible to smoothly achieve the speed increase or maintain the speed at the time of disturbance in the case where the ALC limiter is operating.

[0162] The above is a description of the fifth embodiment.

[0163] [Sixth Embodiment]

[0164] Reference Figure 12 , Figure 13 , Figure 14 A control device 10 according to a sixth embodiment of the present invention will be described. Figure 12is a block diagram schematically showing the control device 10 of the present embodiment. The control device 10 of the present embodiment is provided with the bubble control section 20, the propulsion control section 30, and the storage section 47. In particular, the propulsion control section 30 differs from the first embodiment in that the propulsion mechanism 70 is controlled in accordance with the control of the bubble control section 20. That is, the propulsion control section 30 controls the propulsion force of the propulsion mechanism 70 in accordance with the ejection state of the bubble B of the ejection mechanism 80.

[0165] In addition, in the present embodiment, the propulsion control section 30 differs from the first embodiment in that the propulsion control section 30 is provided with the position acquisition section 41, the propulsion force decision section 42, and the mechanism control section 48. In addition, in the present embodiment, the bubble control section 20 acquires the operation result from the operation section 58, and controls the operation of the ejection mechanism 80 on the basis of the operation result. Therefore, the position acquisition section 41, the propulsion force decision section 42, the mechanism control section 48, and the operation section 58 will be mainly described.

[0166] The operation section 58 is provided at the bridge or the like of the ship 1 so as to be operated by an operator. When the operator performs an operation for starting the operation of the ejection mechanism 80 using the operation section 58, the operation section 58 provides the control device 10 with operation start information (hereinafter, referred to as "ON information"). In addition, when the operator performs an operation for stopping the operation of the ejection mechanism 80 using the operation section 58, the operation section 58 provides the control device 10 with operation stop information (hereinafter, referred to as "OFF information"). When the ON information and the OFF information are collectively referred to, it is referred to as "ON / OFF information". The ON / OFF information is provided to the bubble control section 20 and the propulsion control section 30 in the control device 10. The bubble control section 20 controls the ejection mechanism 80 so as to eject air on the basis of the ON information, and controls the ejection mechanism 80 so as not to eject air on the basis of the OFF information. The propulsion control section 30 controls the propulsion mechanism 70 on the basis of the ON / OFF information. That is, the propulsion control section 30 controls the target propulsion force of the propulsion mechanism 70 in accordance with the control of the bubble control section 20 as to whether or not to eject air.

[0167] The position acquisition section 41 acquires the handle position P of the operation handle 51 of the remote controller 50. The position acquisition section 41 exemplifies an operation state acquisition section. The remote controller 50 transmits a signal corresponding to the handle position P of the operation handle 51 to the position acquisition section 41. The position acquisition section 41 acquires the handle position P on the basis of the reception result of the signal from the remote controller 50.

[0168] The propulsion force determining section 42 determines a target propulsion force E1 of the propulsion mechanism 70 based on the acquired handle position P. The mechanism control section 48 controls the propulsion force by changing at least one of the rotation speed of the main engine 74 and the blade angle W in accordance with the determined target propulsion force E1. For example, in the case where the target propulsion force E1 is increased, the mechanism control section 48 increases the rotation speed of the main engine 74 or increases the blade angle W to increase the propulsion force. In the case where the target propulsion force E1 is decreased, the mechanism control section 48 decreases the rotation speed of the main engine 74 or decreases the blade angle W to decrease the propulsion force.

[0169] For example, in a state where the propulsion force is maintained to be constant, if the bubble control section 20 ejects air, an air lubrication effect is generated, so that the ship speed becomes faster than that in the non-ejection. In order to suppress the variation of the ship speed, it is effective to make the propulsion force in the ejection smaller than that in the non-ejection. Therefore, in the present embodiment, the propulsion force determining section 42 determines based on the control of the bubble control section 20 so that the target propulsion force E1-A in the case where the ejection mechanism 80 is ejecting air (in the ejection) is smaller than the target propulsion force E1-B in the case where the air is not being ejected (in the non-ejection). In this case, it is possible to suppress the variation of the ship speed due to the air lubrication effect.

[0170] The target propulsion force E1 is not particularly limited as long as it is an arbitrary element indicating the propulsion force. In the present embodiment, the target propulsion force E1 is the target rotation speed N1 of the main engine 74. By decreasing the target rotation speed N1 as the target propulsion force E1, it is possible to easily suppress the variation of the ship speed due to the decrease of the frictional resistance, and it is possible to save the fuel consumption of the main engine 74. As another example, the target propulsion force E1 can also be the target blade angle W1 of the propeller blade 73. By decreasing the target blade angle W1 as the target propulsion force E1, it is possible to easily suppress the variation of the ship speed due to the decrease of the frictional resistance, and it is possible to decrease the load of the main engine 74 to save the fuel consumption.

[0171] The example in which the target propulsion force E1 is the target rotation speed N1 will be specifically described. Figure 13 is a graph showing a table TBL1 regarding the target propulsion force E1-B (second target rotation speed N1-B) in the non-ejection, the target propulsion force E1-A (first target rotation speed N1-A) in the ejection, and the target ship speed corresponding to the handle position P of the operation handle 51. The unit of the rotation speed is [rpm], and the unit of the ship speed is [knot]. When the operation handle 51 is in the upper limit position, the handle position P is indicated as 100%, when the operation handle 51 is in the neutral position, the handle position P is indicated as 0%, and when the operation handle 51 is in the lower limit position, the handle position P is indicated as -100%.

[0172] The propulsion force determination unit 42 determines one of the first target rotation speed N1-A corresponding to the handle position P and the ON information and the second target rotation speed N1-B corresponding to the handle position P and the OFF information as the target rotation speed N1 using the table TBL1.

[0173] For example, in the non-air-blowing state, in the case where the boat is sailing at the handle position P = 55% and the second target rotation speed N1-B = 60 rpm, if there is no disturbance in the still water, the boat speed is 14 knots (target boat speed). In this state, if the air-blowing mechanism 80 blows air while maintaining the second target rotation speed N1-B, the boat speed becomes faster due to the air lubrication effect. Here, by switching the target rotation speed to the first target rotation speed N1-A = 58 rpm, the boat speed becomes 14 knots, and thus the boat speed variation can be suppressed. That is, by switching the target rotation speed N1 between the non-air-blowing state and the air-blowing state for the same handle position P, the boat speed variation can be suppressed.

[0174] Next, the reduction amount DWE of the target propulsion force E1-A in the air-blowing state with respect to the target propulsion force E1-B in the non-air-blowing state will be described. The reduction amount DWE is obtained by subtracting the target propulsion force E1-A from the target propulsion force E1-B. Here, the reduction amount DWN of the first target rotation speed N1-A in the air-blowing state with respect to the second target rotation speed N1-B in the non-air-blowing state will be described as an example. The reduction amount DWN is obtained by subtracting the first target rotation speed N1-A from the second target rotation speed N1-B.

[0175] The air lubrication effect varies due to various variation factors. As an example of the variation factors that vary the air lubrication effect, the boat speed, the actual rotation speed, the draft, and the like are given. For example, in the case where the boat speed is fast, the actual rotation speed N2 of the main engine 74 is large, or the draft is deep, the air lubrication effect is relatively improved. In the case where the air lubrication effect is improved, if the reduction amount DWE of the propulsion force is fixed, the suppression of the boat speed variation in the air-blowing state and the non-air-blowing state becomes insufficient. Therefore, in the present embodiment, the propulsion force determination unit 42 varies the reduction amount DWE of the propulsion force in accordance with the variation factors of the air lubrication effect.

[0176] In the present embodiment, the propulsion force determination unit 42 determines the target propulsion force E1 in such a manner that the reduction amount DWE of the propulsion force increases as the boat speed increases. In this example, the propulsion force determination unit 42 determines the target rotation speed N1 in such a manner that the reduction amount DWN of the rotation speed increases as the boat speed increases.

[0177] The reduction width DWE, the reduction width DWN can be continuously increased or decreased with respect to the ship speed, or can be increased or decreased in steps with respect to the ship speed. The propulsion force determination unit 42 has a plurality of tables TBL1 corresponding to a plurality of ship speeds, and determines using a table TBL1 selected from the plurality of tables TBL1 according to the actual ship speed. For example, the propulsion force determination unit 42 can acquire the ship speed from a ship speed sensor capable of detecting the ship speed.

[0178] In addition, in the present embodiment, the propulsion force determination unit 42 determines the target propulsion force E1 in such a manner that the reduction width DWE of the propulsion force increases as the actual rotation speed N2 increases. In this example, the propulsion force determination unit 42 determines the target rotation speed N1 in such a manner that the reduction width DWN of the rotation speed increases as the actual rotation speed N2 increases.

[0179] The reduction width DWE, the reduction width DWN can be continuously increased or decreased with respect to the actual rotation speed N2, or can be increased or decreased in steps with respect to the actual rotation speed N2. The propulsion force determination unit 42 has a plurality of tables TBL1 corresponding to a plurality of actual rotation speeds N2, and determines using a table TBL1 selected from the plurality of tables TBL1 according to the actual rotation speed N2. For example, the propulsion force determination unit 42 can acquire the actual rotation speed N2 from a sensor (not shown) capable of detecting the actual rotation speed N2.

[0180] In addition, in the present embodiment, the propulsion force determination unit 42 determines the target propulsion force E1 in such a manner that the reduction width DWE of the propulsion force increases as the draft increases. In this example, the propulsion force determination unit 42 determines the target rotation speed N1 in such a manner that the reduction width DWN of the rotation speed increases as the draft increases.

[0181] The reduction width DWE, the reduction width DWN can be continuously increased or decreased with respect to the draft, or can be increased or decreased in steps with respect to the draft. The propulsion force determination unit 42 has a plurality of tables TBL1 corresponding to a plurality of drafts, and determines using a table TBL1 selected from the plurality of tables TBL1 according to the actual draft. For example, the propulsion force determination unit 42 can acquire the draft from a sensor (not shown) capable of detecting the draft.

[0182] As described above, by changing the reduction width DWE, the reduction width DWN according to any one or more of the ship speed, the actual rotation speed, and the draft, it is possible to further suppress the variation in the ship speed.

[0183] The operation S160 of the control device 10 of the present embodiment configured as described above will be described. Figure 14 is a flowchart showing the operation S160 of the control device 10.

[0184] When the process S160 is started, the position acquisition part 41 acquires the handle position P of the operation handle 51 from the remote controller 50 (step S161).

[0185] After the step S161 is executed, the propulsion force decision part 42 acquires the ship speed, the actual rotation speed, the draft, and the like, which are the fluctuation elements (step S162). After the fluctuation elements are acquired, the propulsion force decision part 42 selects the table TBL1 according to the fluctuation elements (step S163). In this step, the propulsion force decision part 42 selects the table TBL1 to which the reduction width DWE, the reduction width DWN corresponding to the fluctuation elements are applied.

[0186] After the step S163 is executed, the propulsion force decision part 42 determines whether it is the spouting time based on the ON / OFF information (step S164). In the case where it is not the spouting time (NO in step S164), the propulsion force decision part 42 supplies the second target rotation speed N1-B at the non-spouting time to the mechanism control part 48, and the mechanism control part 48 controls the propulsion mechanism 70 at the second target rotation speed N1-B at the non-spouting time (step S165). After the step S165 is executed, the S160 is ended.

[0187] In the case where it is the spouting time (YES in step S164), the propulsion force decision part 42 supplies the first target rotation speed N1-A at the spouting time to the mechanism control part 48, and the mechanism control part 48 controls the propulsion mechanism 70 at the first target rotation speed N1-A at the spouting time (step S166). After the step S166 is executed, the S160 is ended. The above-described steps are only an example, and various modifications can be made.

[0188] The features of the control device 10 of the present embodiment are described. In the present embodiment, the propulsion control part 30 controls the propulsion mechanism 70 according to the control of the bubble control part 20. In this case, it is possible to reduce the energy consumption amount (fuel consumption amount) of the propulsion mechanism 70 according to the control of the bubble control part 20.

[0189] In the present embodiment, the propulsion mechanism 70 has the main engine 74 that rotates the propeller 75. In addition, the propulsion control part 30 controls the propulsion mechanism 70 so that the target propulsion force at the spouting time when the bubble control part 20 spouts air is smaller than the target propulsion force at the non-spouting time when air is not spouted. In this case, it is possible to suppress the ship speed fluctuation at the non-spouting time and the spouting time.

[0190] In the present embodiment, the propulsion control part 30 increases the reduction width of the target propulsion force at the spouting time with respect to the target propulsion force at the non-spouting time as the ship speed of the ship 1 or the actual rotation speed of the main engine 74 increases. In this case, it is possible to further suppress the ship speed fluctuation at the non-spouting time and the spouting time.

[0191] In the present embodiment, the target propulsive force is a target rotation speed of the main engine 74. In this case, the variation in the ship speed at the time of non-bubbling and at the time of bubbling can be suppressed.

[0192] In the present embodiment, the propeller 75 is a variable pitch propeller 72 capable of changing the pitch angle of the propeller blade 73, and the target propulsive force is a target pitch angle of the propeller blade 73. In this case, the variation in the ship speed at the time of non-bubbling and at the time of bubbling can be suppressed.

[0193] The above is the explanation of the sixth embodiment. The table TBL1 of the present embodiment can be set based on theoretical values obtained by simulation or prescribed calculation. The table TBL1 can be set based on data at the time of sea trial operation, and can be updated based on data at the time of sea trial operation or data in operation. The table TBL1 can include data of the actual rotation speed and the ship speed, can include data of the actual rotation speed and the load (shaft horsepower) of the main engine 74, and can include data of the actual rotation speed and the fuel consumption of the main engine 74.

[0194] [Seventh Embodiment]

[0195] The seventh embodiment of the present application is a control method of the control device 10. The control method includes the step of controlling, by the control device 10 that controls the bubbling mechanism 80 for bubbling the air bubbles B toward the water from the air outlet 84 provided to the hull 90 of the ship 1 and the propulsive mechanism 70 for propelling the hull 90, one of the bubbling mechanism 80 and the propulsive mechanism 70 in accordance with the control of the other.

[0196] According to the present embodiment, the same effects and advantages as those of the first embodiment are exerted.

[0197] [Eighth Embodiment]

[0198] The eighth embodiment of the present application is a control program 100 (computer program) of the control device 10. The control program 100 is for causing a computer to execute the step of controlling, by the control device 10 that controls the bubbling mechanism 80 for bubbling the air bubbles B toward the water from the air outlet 84 provided to the hull 90 of the ship 1 and the propulsive mechanism 70 for propelling the hull 90, one of the bubbling mechanism 80 and the propulsive mechanism 70 in accordance with the control of the other.

[0199] These functions of the control program 100 can also be installed in the storage means (for example, the storage 47) of the control device 10 as an application program in which a plurality of modules corresponding to the functional blocks of the control device 10 are installed. The control program 100 can also be read out from the main memory of the processor (for example, the CPU) of the computer incorporated in the control device 10 to be executed.

[0200] According to the present embodiment, the same effects as those of the first embodiment are exerted.

[0201] The above describes examples of the embodiments of the present application in detail. The above-described embodiments are merely examples for illustrating specific examples when the present application is implemented. The contents of the embodiments are not intended to limit the technical scope of the present application, and various design changes such as changes, additions, deletions, and the like of the constituent elements can be made within the scope of the idea of the present application defined by the claims. In the above-described embodiments, the contents that can be subjected to such design changes are described with the expressions such as "embodiment" and "in the embodiment", but the design changes are not excluded from the contents that do not have such expressions.

[0202] [Modified Example]

[0203] Next, a modified example will be described. In the drawings and description of the modified example, the same reference numerals are attached to the constituent elements and members that are the same as or equivalent to those of the embodiments. The description that is repeated from the embodiments is appropriately omitted, and the structure that is different from the embodiments is mainly described.

[0204] In the description of the embodiments, an example in which the propulsion mechanism 70 obtains the propulsive force by rotating the propeller 75 by the prime mover 79 is shown, but is not limited thereto. The propulsion mechanism can be a mechanism that is capable of propelling the hull, and for example, can be a mechanism that ejects gas or the like and obtains the propulsive force by the reaction force thereof.

[0205] In the description of the embodiments, an example in which the prime mover 79 is a diesel engine is shown, but is not limited thereto. The prime mover can be, for example, an internal combustion engine other than the diesel engine, an external combustion engine, an electric motor, or the like.

[0206] In the description of the embodiments, an example in which the operator inputs the disturbance data to the control device 10 is shown, but is not limited thereto. For example, a structure can be adopted in which a sensor that is capable of detecting the disturbance data is provided, and the control device acquires the detection result of the sensor.

[0207] The above-described modified example exerts the same effects as those of each of the embodiments.

[0208] Any combination of the above-described embodiments and modified examples is also useful as an embodiment of the present application. The new embodiment that is generated by the combination has the effects of each of the embodiments and modified examples that are combined.

[0209] Explanation of Reference Numerals

[0210] 1: ship; 10: control device; 20: bubble control section; 30: propulsion control section; 31: period decision section; 32: overload prediction section; 33: position determination section; 34: acceleration / deceleration determination section; 35: gear shift determination section; 36: command reception section; 37: load prediction section; 38: limit signal reception section; 39: release signal reception section; 41: position acquisition section; 42: propulsion force decision section; 47: storage section; 50: remote controller; 51: operation handle; 58: operation section; 67: torque limiter; 68: scavenging pressure limiter; 69: ALC limiter; 70: propulsion mechanism; 72: variable pitch propeller; 73: propeller blade; 74: main engine; 75: propeller; 78: propulsion shaft; 79: prime mover; 80: ejection mechanism; 84: air outlet; 90: hull; 92: bottom.

Claims

1. A control device comprising: a bubble control section that controls an ejection mechanism for ejecting bubbles toward water from an air outlet provided in a hull of a ship; and a propulsion control section that controls a propulsion force of a propulsion mechanism for propelling the hull, one of the propulsion control section and the bubble control section being controlled in accordance with control of the other, the bubble control section controlling the ejection mechanism in accordance with control of the propulsion control section, the control device further comprising a command reception section that receives a command signal for indicating a magnitude of the propulsion force of the propulsion mechanism and an actual signal representing a magnitude of a current propulsion force, the propulsion control section controlling the propulsion force of the propulsion mechanism on the basis of a comparison result of the command signal and the actual signal, the bubble control section increasing an ejection amount of bubbles in a case where the command signal indicates an increase in speed or decreasing the ejection amount of bubbles in a case where the command signal indicates a decrease in speed, the propulsion mechanism having a main engine that rotates a propeller, the command signal being a signal for indicating a target rotation speed of the main engine, the actual signal being an actual rotation speed that is a current rotation speed of the main engine, the control device further comprising an overload prediction section that predicts whether a load of the main engine exceeds a prescribed load on the basis of the target rotation speed, the actual rotation speed, and a current fuel input amount of the main engine, the bubble control section increasing the ejection amount of bubbles in a case where it is predicted by the overload prediction section that the prescribed load is exceeded.

2. The control device according to claim 1, wherein the propeller is a variable-pitch propeller that can change a pitch angle of a propeller blade, the command signal is a target pitch angle of the variable-pitch propeller, the actual signal is an actual pitch angle that is a current pitch angle of the variable-pitch propeller, and the overload prediction section predicts whether the load of the main engine exceeds the prescribed load on the basis of the target pitch angle and the actual pitch angle.

3. The control device according to claim 2, wherein the overload prediction section further predicts whether the load of the main engine exceeds the prescribed load on the basis of at least one of a target value of a speed at which the pitch angle is changed from the actual pitch angle to the target pitch angle and a target value of a speed at which the rotation speed of the main engine is changed from the actual rotation speed to the target rotation speed. wherein 4. The control device according to claim 1, wherein the control device comprises an acceleration and deceleration determination section that determines whether the hull is accelerated or decelerated on the basis of at least one of a fuel input amount input to the main engine and the actual rotation speed, and the bubble control section performs at least one of a first action of increasing the ejection amount of bubbles in a case where it is determined by the acceleration and deceleration determination section that the hull is accelerated and a second action of decreasing the ejection amount of bubbles in a case where it is determined by the acceleration and deceleration determination section that the hull is decelerated.

5. The control device according to claim 1, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ has a position judging section that acquires a position signal indicating a position of the ship, judges whether the ship is located within a harbor based on the position signal, the bubble control section reduces the amount of bubbles to be ejected in a case where the position judging section judges that the ship is located within the harbor.

6. The control device according to claim 1, wherein the propulsion control section controls the propulsion mechanism in accordance with the control of the bubble control section.

7. The control device according to claim 6, wherein the propulsion control section controls the propulsion mechanism so that a target propulsion force at a time of ejection of air by the bubble control section is smaller than a target propulsion force at a time of non-ejection of air.

8. The control device according to claim 7, wherein the propulsion control section increases a reduction amount of the target propulsion force at the time of ejection relative to the target propulsion force at the time of non-ejection as a ship speed or an actual rotation speed of the main engine increases.

9. The control device according to claim 7 or 8, wherein the target propulsion force is a target rotation speed of the main engine.

10. The control device according to claim 7 or 8, wherein the propeller is a variable pitch propeller capable of changing a blade angle of a propeller blade, the target propulsion force is a target blade angle of the propeller blade.

11. A control device comprising: a bubble control section that controls an ejection mechanism for ejecting bubbles toward water from an air outlet provided to a hull of a ship; and a propulsion control section that controls a propulsion force of a propulsion mechanism for propelling the hull, wherein one of the propulsion control section and the bubble control section is controlled in accordance with the control of the other, the bubble control section controls the ejection mechanism in accordance with the control of the propulsion control section, the control device further comprises an instruction receiving section that receives an instruction signal for instructing a magnitude of the propulsion force of the propulsion mechanism and an actual signal indicating a magnitude of a current propulsion force, the propulsion control section controls the propulsion force of the propulsion mechanism based on a comparison result of the instruction signal and the actual signal, the bubble control section increases the amount of bubbles to be ejected in a case where the instruction signal indicates an increase in speed, or reduces the amount of bubbles to be ejected in a case where the instruction signal indicates a decrease in speed, the propulsion mechanism has a prime mover that rotates a propeller, the control device comprises a shift judging section that judges whether a shift instruction to enter a rotation speed range is received in a case where a current actual rotation speed of the prime mover is outside the rotation speed range set in advance, the bubble control section increases the amount of bubbles to be ejected in a case where the shift judging section judges that the shift instruction to enter the rotation speed range is received.

12. The control device according to claim 11, wherein the shift judging section judges whether the shift instruction to enter the rotation speed range is received based on an operation state of an operation section that remotely operates the prime mover.

13. A control device comprising: a bubble control section that controls an ejection mechanism for ejecting bubbles toward water from an air outlet provided to a hull of a ship, a propulsion control section that controls a propulsion force of a propulsion mechanism for propelling the hull, wherein, one of the propulsion control section and the bubble control section is controlled in accordance with control by the other, the bubble control section controls the ejection mechanism in accordance with control by the propulsion control section, the propulsion mechanism has a main engine that rotates a propeller, the control device includes a load prediction section that predicts whether a load of the main engine exceeds a prescribed load, based on a fuel input amount currently input to the main engine and an actual rotation speed of the main engine, in a case where it is predicted by the load prediction section that the load of the main engine exceeds the prescribed load, the bubble control section causes the ejection mechanism to perform a bubble generation preparation operation.

14. The control device according to claim 13, wherein the load prediction section further predicts whether the load of the main engine exceeds the prescribed load, based on at least one of a tidal current at a water area in which the ship sails, a wind, a predetermined route in which the ship sails, a draft of the hull, a target rotation speed, and a target fuel input amount.

15. A control device including: a bubble control section that controls an ejection mechanism for ejecting bubbles toward water from an air outlet provided to a hull of a ship, a propulsion control section that controls a propulsion force of a propulsion mechanism for propelling the hull, wherein one of the propulsion control section and the bubble control section is controlled in accordance with control by the other, the bubble control section controls the ejection mechanism in accordance with control by the propulsion control section, the propulsion mechanism has a main engine that rotates a propeller, the control device includes a limit signal receiving section that receives a limit signal indicating that a load of the main engine exceeds a prescribed load, in a case where the limit signal receiving section receives the limit signal, the bubble control section increases an ejection amount of bubbles.

16. The control device according to claim 15, wherein a cancel signal receiving section that receives a limit cancel signal indicating that the load of the main engine is equal to or less than the prescribed load, in a case where a prescribed cancel condition including that the cancel signal receiving section receives the limit cancel signal is satisfied, the bubble control section decreases the ejection amount of bubbles.

17. The control device according to claim 16, wherein the prescribed cancel condition includes that an actual rotation speed of the main engine reaches a target rotation speed.

18. The control device according to claim 16 or 17, wherein the prescribed cancel condition includes that a prescribed standby period elapses from when the limit signal is received.

19. The control device according to claim 18, wherein Further provided is a period determining unit that determines the standby period based on first interference data that is interference data of a point in time at which the restriction signal is received and second interference data that is interference data of a point in time at which the restriction release signal is received, wherein the interference data is a magnitude of interference that is a prescribed factor that affects at least one of a propulsion speed and a propulsion direction of the ship.

20. The control device according to any one of claims 15 to 17, wherein the restriction signal includes a restriction signal generated by a torque limiter in a case where a torque of the main engine exceeds a threshold value and a restriction signal generated by a scavenge pressure limiter in a case where a scavenge pressure of the main engine exceeds a threshold value.

21. The control device according to any one of claims 15 to 17, wherein the propeller is a variable pitch propeller that can change a pitch angle of a propeller blade, the propulsion mechanism has an automatic load control limiter (ALC limiter) that reduces an output of the main engine in a case where an actual load is higher than a target load, the restriction signal includes a restriction signal generated by the ALC limiter in a case where the actual load is higher than the target load.

22. A control method of a control device, comprising the steps of: controlling one of an air blowing mechanism and a propulsion mechanism by a control device that controls the air blowing mechanism and the propulsion mechanism, wherein the air blowing mechanism blows air bubbles toward water from an air outlet provided in a hull of a ship, and the propulsion mechanism propels the hull, the propulsion mechanism having a main engine that rotates a propeller; controlling the air blowing mechanism based on control of the propulsion mechanism; receiving an instruction signal that indicates a magnitude of a propulsion force of the propulsion mechanism and an actual signal that indicates a magnitude of a current propulsion force; controlling the propulsion force of the propulsion mechanism based on a comparison result of the instruction signal and the actual signal; and increasing an air bubble blowing amount in a case where the instruction signal indicates an increase in speed or decreasing the air bubble blowing amount in a case where the instruction signal indicates a decrease in speed, wherein the instruction signal is a signal that indicates a target rotation speed of the main engine, the actual signal is an actual rotation speed that is a current rotation speed of the main engine, the control method further includes the step of predicting whether a load of the main engine exceeds a prescribed load based on the target rotation speed, the actual rotation speed, and a current fuel input amount of the main engine, increasing the air bubble blowing amount in a case where the prediction is that the prescribed load is exceeded.

23. A control method of a control device, comprising the steps of: controlling one of an air blowing mechanism and a propulsion mechanism by a control device that controls the air blowing mechanism and the propulsion mechanism, wherein the air blowing mechanism blows air bubbles toward water from an air outlet provided in a hull of a ship, and the propulsion mechanism propels the hull, the propulsion mechanism having a prime mover that rotates a propeller; controlling the propelling mechanism in accordance with the control of the propelling mechanism; receiving an instruction signal indicating a magnitude of a propelling force of the propelling mechanism and an actual signal representing a current magnitude of the propelling force; controlling the propelling force of the propelling mechanism based on a comparison result of the instruction signal and the actual signal; increasing the amount of the bubbles to be ejected in a case where the instruction signal indicates an increase in the speed, or decreasing the amount of the bubbles to be ejected in a case where the instruction signal indicates a decrease in the speed; determining whether a shift instruction to shift into the range of the rotational speed is received in a case where the current actual rotational speed of the prime mover is outside the range of the rotational speed set in advance; and increasing the amount of the bubbles to be ejected in a case where it is determined that the shift instruction to shift into the range of the rotational speed is received.

24. A control method of a control device, comprising the steps of: controlling one of an ejecting mechanism and a propelling mechanism by a control device that controls the ejecting mechanism and the propelling mechanism, wherein the ejecting mechanism ejects bubbles toward water from an air outlet provided to a hull of a ship, and the propelling mechanism propels the hull, the propelling mechanism having a main engine that rotates a propeller; controlling the ejecting mechanism in accordance with the control of the propelling mechanism; predicting whether a load of the main engine exceeds a prescribed load based on a current amount of fuel input to the main engine and an actual rotational speed of the main engine; and causing the ejecting mechanism to perform a generation preparation operation of the bubbles in a case where it is predicted that the load of the main engine exceeds the prescribed load.

25. A control method of a control device, comprising the steps of: controlling one of an ejecting mechanism and a propelling mechanism by a control device that controls the ejecting mechanism and the propelling mechanism, wherein the ejecting mechanism ejects bubbles toward water from an air outlet provided to a hull of a ship, and the propelling mechanism propels the hull, the propelling mechanism having a main engine that rotates a propeller; controlling the ejecting mechanism in accordance with the control of the propelling mechanism; receiving a limit signal indicating that a load of the main engine exceeds a prescribed load; and increasing the amount of the bubbles to be ejected in a case where the limit signal is received.

26. A computer program product including a control program of a control device, the control program causing a computer to execute the steps of: The control device controls one of the ejection mechanism and the propulsion mechanism in accordance with the control of the other of the ejection mechanism and the propulsion mechanism, wherein the ejecting mechanism ejects bubbles toward water from an air outlet provided to a hull of a ship, and the propelling mechanism propels the hull, the propelling mechanism having a main engine that rotates a propeller; controlling the ejecting mechanism in accordance with the control of the propelling mechanism; receiving an instruction signal indicating a magnitude of a propelling force of the propelling mechanism and an actual signal representing a current magnitude of the propelling force; controlling the propelling force of the propelling mechanism based on a comparison result of the instruction signal and the actual signal; and increasing the amount of the bubbles to be ejected in a case where the instruction signal indicates an increase in the speed, or decreasing the amount of the bubbles to be ejected in a case where the instruction signal indicates a decrease in the speed, wherein the instruction signal is a signal indicating a target rotational speed of the main engine, the actual signal is an actual rotation speed that is a current rotation speed of the main engine, the control program further causes the computer to execute a step of predicting whether the load of the main engine exceeds a prescribed load, based on the target rotation speed, the actual rotation speed, and a current fuel input amount to the main engine, in a case where the prediction is that the prescribed load is exceeded, increasing the amount of bubble emission.

27. A computer program product including a control program that controls an apparatus, the control program causing a computer to execute the steps of: The control device controls one of the ejection mechanism and the propulsion mechanism in accordance with the control of the other of the ejection mechanism and the propulsion mechanism, wherein the emission mechanism is for emitting bubbles toward water from an air outlet provided to a hull of a ship, the propulsion mechanism is for propelling the hull, and the propulsion mechanism has a prime mover that rotates a propeller; controlling the emission mechanism in accordance with control of the propulsion mechanism; receiving an instruction signal that indicates a magnitude of a propulsion force of the propulsion mechanism and an actual signal that represents a current magnitude of the propulsion force; controlling the propulsion force of the propulsion mechanism based on a comparison result of the instruction signal and the actual signal; in a case where the instruction signal indicates an increase in speed, increasing the amount of bubble emission, or in a case where the instruction signal indicates a decrease in speed, decreasing the amount of bubble emission; in a case where the current actual rotation speed of the prime mover is outside a preset rotation speed range, determining whether a shift instruction into the rotation speed range is received; and in a case where it is determined that the shift instruction into the rotation speed range is received, increasing the amount of bubble emission.

28. A computer program product including a control program that controls an apparatus, the control program causing a computer to execute the steps of: The control device controls one of the ejection mechanism and the propulsion mechanism in accordance with the control of the other of the ejection mechanism and the propulsion mechanism, wherein the emission mechanism is for emitting bubbles toward water from an air outlet provided to a hull of a ship, the propulsion mechanism is for propelling the hull, and the propulsion mechanism has a main engine that rotates a propeller; controlling the emission mechanism in accordance with control of the propulsion mechanism; predicting whether a load of the main engine exceeds a prescribed load, based on a current fuel input amount to the main engine and an actual rotation speed of the main engine; and in a case where the prediction is that the load of the main engine exceeds the prescribed load, causing the emission mechanism to perform a bubble generation preparation action.

29. A computer program product including a control program that controls an apparatus, the control program causing a computer to execute the steps of: The control device controls one of the ejection mechanism and the propulsion mechanism in accordance with the control of the other of the ejection mechanism and the propulsion mechanism, wherein the emission mechanism is for emitting bubbles toward water from an air outlet provided to a hull of a ship, the propulsion mechanism is for propelling the hull, and the propulsion mechanism has a main engine that rotates a propeller; controlling the emission mechanism in accordance with control of the propulsion mechanism; receiving a limit signal that indicates that a load of the main engine exceeds a prescribed load; and in a case where the limit signal is received, increasing the amount of bubble emission. ​

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