Program for identifying desirable moment of inertia for flywheel of ship, and system for realizing ship having flywheel with desirable moment of inertia

Abstract

A terminal device 16: acquires, by a set parameter acquisition unit 1611 and as the value of a set parameter, a set value of a rotation speed of a propeller shaft 12 of a ship which is sailing a real sea area; and acquires, by a realized parameter acquisition unit 1612 and as the values of realized parameters, the values of a wave direction, a wave period, a wave height, a tidal direction, a tidal speed, a wind direction, a wind speed, draft, and a travelling direction of the ship which is sailing the real sea area. The terminal device 16 identifies, by a moment-of-inertia identification unit 1616 and through using a machine learning model L, the value of an inertia parameter of a flywheel according to the combination of the acquired values of the parameters. The value of the inertia parameter is for reducing the energy consumption rate of the ship. The terminal device 16 outputs, to a flywheel system comprising a function for changing the moment of inertia of the flywheel, moment-of-inertia data indicating the value of the moment-of-inertia identified by the moment of inertia identification unit 1616.

Description

Program for identifying a desired moment of inertia for a ship's flywheel, and system for realizing a ship equipped with a flywheel having the desired moment of inertia

[0001] The present invention relates to a technique for reducing energy consumption associated with the navigation of a ship.

[0002] The propeller of a ship underway is subjected to fluctuating loads from the surrounding fluid, such as waves. Even if the propulsion engine is set to output a constant power output, the actual power output of the ship's propeller fluctuates due to these loads. As a result, the propeller's rotation speed per unit time (rpm, hereafter referred to as "propeller speed") fluctuates, resulting in an increase in the energy consumption rate (energy consumption per unit distance traveled) compared to when sailing on calm waters.

[0003] To alleviate the above problems, a technology has been proposed that involves installing a load called a flywheel that rotates in conjunction with the rotation of the ship's propeller shaft, and smoothing the propeller rotation speed by adjusting the moment of inertia of the propeller shaft in response to changes in the load on the propeller.

[0004] For example, Patent Document 1 proposes a mechanism for smoothing the rotational speed of the propeller by using a variable speed mechanism to reduce the gear ratio between the flywheel and the propeller shaft when the load torque applied to the propeller shaft increases, and applying the inertial force of the flywheel to the propeller shaft, and by using a variable speed mechanism to increase the gear ratio between the flywheel and the propeller shaft when the load torque applied to the propeller shaft decreases, and applying the inertial force of the propeller shaft to the flywheel.

[0005] Japanese Utility Model Application Laid-Open Publication No. 4-56248

[0006] The greater the moment of inertia of the flywheel that rotates in conjunction with the propeller shaft of the ship, the smoother the rotation speed of the propeller.

[0007] When large ships travel long distances, they often travel at a constant speed for long periods of time to reduce the rate of energy consumption associated with navigation. In such cases, the amount of energy required to increase the rotational speed of the flywheel when the ship begins to navigate is generally significantly smaller than the amount of energy saved by the flywheel smoothing the rotational speed of the propeller during subsequent navigation.

[0008] Therefore, in large ships that sail long distances, the larger the moment of inertia of the flywheels installed, the more the energy consumption rate associated with sailing can be reduced.

[0009] However, in a ship, there are restrictions on the size and shape of the engine room that houses the main propulsion engine and its peripheral devices such as the flywheel, etc. Therefore, the maximum value of the moment of inertia of the flywheel that can be installed on a ship is naturally determined by the size and shape of the engine room.

[0010] The inventors of the present application have realized that maximizing the moment of inertia of the flywheel in a ship to the extent permitted by the size and shape of the engine room does not necessarily result in minimizing the energy consumption rate associated with the navigation of the ship.

[0011] For example, if the torque applied to the propeller shaft fluctuates periodically, the propeller rotation speed also fluctuates periodically in response to that fluctuation, but a phase difference occurs between these fluctuations. This phase difference affects the energy consumption rate. This phase difference, in turn, varies depending on the magnitude of the flywheel's moment of inertia. Therefore, adjusting the flywheel's moment of inertia may potentially reduce the energy consumption rate during ship navigation.

[0012] The phase difference between torque and propeller rotation speed is one example of why the magnitude of the flywheel's moment of inertia affects the energy consumption rate during ship navigation. In situations where the load on the propeller shaft varies depending on the ship's navigation conditions, the magnitude of the flywheel's moment of inertia may also affect the energy consumption rate during ship navigation for other unknown reasons.

[0013] In view of the above circumstances, the present invention provides a means for reducing the energy consumption rate associated with the navigation of a ship by adjusting the moment of inertia of a flywheel that rotates in conjunction with the rotation of the propeller shaft of the ship.

[0014] In order to solve the above-mentioned problems, the present invention provides a program for causing a computer to execute a process for identifying the value of the moment of inertia of a flywheel that rotates in conjunction with the rotation of a propeller shaft of a ship, based on a combination of the value of a setting parameter, which is a parameter related to a value that is set so that the output of the ship's main propulsion engine approaches a specific value or a parameter related to a value for estimating the set value, and the value of an actualization parameter, which is a parameter related to the value of the output realized by the ship's propeller or a parameter related to a value for estimating the value of the output.

[0015] Once the values ​​of the set parameters and realized parameters of the vessel are obtained, the energy consumption rate associated with the navigation of the vessel can be reduced by using a flywheel with a moment of inertia specified by a computer operating according to the program of the present invention.

[0016] 1 is a diagram showing the overall configuration of a system according to an embodiment; FIG. 2 is a diagram showing the hardware configuration of a terminal device according to an embodiment; FIG. 3 is a diagram showing the functional configuration of a terminal device according to an embodiment; FIG. 4 is a diagram showing the configuration of a flywheel system according to an embodiment; FIG. 5 is a diagram showing the data configuration of a log table stored in a terminal device according to an embodiment; FIG. 6 is an example of a graph showing the relationship between the value of the moment of inertia of a flywheel specified by a terminal device according to an embodiment and the energy consumption rate; FIG. 7 is an example of a graph showing the relationship between the value of the moment of inertia of a flywheel specified by a terminal device according to an embodiment and the energy consumption rate; FIG. 8 is a diagram showing the configuration of a flywheel system according to a modified example; FIG. 9 is a diagram showing the configuration of a flywheel according to a modified example; FIG. 10 is a diagram showing the configuration of a flywheel system according to a modified example; FIG. 11 is a diagram showing the hardware configuration of a server device according to a modified example; FIG. 12 is a diagram showing the functional configuration of a server device according to a modified example.

[0017] 1 is a diagram showing the overall configuration of a system 1 according to one embodiment of the present invention. The system 1 includes a main propulsion engine 11, a propeller shaft 12, a propeller 13, a flywheel system 14, a control stand 15, a terminal device 16, a satellite communication unit 17, and a server device 18.

[0018] Of the components of the system 1 described above, all except the server device 18 are installed on the ship 9, and the server device 18 is located on land.

[0019] The main propulsion engine 11 is a device that generates propulsive force for the navigation of the ship 9, and may be, for example, an internal combustion engine such as a diesel engine, or an electrically powered motor. The main propulsion engine 11 has a rotating main shaft, and drives and rotates the main shaft when in operation.

[0020] The propeller shaft 12 is connected to the main shaft of the main propulsion engine 11 and is a shaft that rotates as the main propulsion engine 11 operates. The torque that the main propulsion engine 11 applies to the propeller shaft via the main shaft is the output torque of the main propulsion engine 11.

[0021] The propeller 13 is attached to the stern end of the propeller shaft 12, has a plurality of blade-shaped members, and rotates with the rotation of the propeller shaft 12 to move the ship 9 forward.

[0022] The flywheel system 14 is a system for smoothing the propeller rotation speed of the propeller 13, and will be described in detail later.

[0023] The control console 15 is a device that is placed on the bridge or in the control room and allows the crew to perform operations such as steering and adjusting the ship's speed.

[0024] The terminal device 16 is a device that constitutes a data processing system that instructs the flywheel system 14 to change the moment of inertia of the flywheel (described later) so as to reduce the rate of energy consumption associated with the navigation of the ship 9.

[0025] The satellite communication unit 17 is connected to the terminal device 16 and is a device that relays data communication between the terminal device 16 and the server device 18 via the satellite communication system.

[0026] The server device 18 is a server device that receives training data (described later) transmitted from the ship 9 and each of the ships of the same or similar type as the ship 9, updates the machine learning model (described later) using the received training data, and transmits the updated machine learning model or machine learning model data indicating its parameter values ​​to each of those ships.

[0027] 2 is a diagram showing the hardware configuration of the terminal device 16. The hardware of the terminal device 16 is a computer for the terminal device. That is, the terminal device 16 includes a processor 1601 that performs various data processing according to a program, a memory 1602 that stores various data including the program executed by the processor 1601, a display 1603 that displays characters, images, etc. to the user, an input device 1604 such as a keyboard that accepts data input by the user, and an input / output interface 1605 that inputs and outputs data to and from external devices.

[0028] The input / output interface 1605 is connected to the flywheel system 14, the control platform 15, and the satellite communication unit 17.

[0029] The memory 1602 stores data persistently, and includes volatile memory that stores data persistently only while power is being supplied, and nonvolatile memory that stores data persistently even when power is cut off. For example, programs executed by the processor 1601 are stored in the nonvolatile memory of the memory 1602. Furthermore, for example, data that is temporarily generated when the processor 1601 performs various data processing according to the programs is stored in the volatile memory of the memory 1602.

[0030] In addition, in the configuration shown in Figure 2, some of the components (e.g., display 1603, input device 1604, etc.) that are built into the computer that is the hardware of the terminal device 16 may be external devices connected to the input / output interface 1605.

[0031] Fig. 3 is a diagram showing the functional configuration of the terminal device 16. That is, a processor 1601 of a computer (see Fig. 2), which is the hardware of the terminal device 16, executes various data processes in accordance with a program for the terminal device 16 according to this embodiment, thereby realizing a data processing system having the components shown in Fig. 3. The functional configuration of the terminal device 16 shown in Fig. 3 will be described below.

[0032] The storage unit 1610 stores various types of data.

[0033] The setting parameter acquisition unit 1611 acquires setting parameter data indicating the value of a setting parameter. The setting parameter is a parameter related to a value that is set so that the output of the main propulsion engine 11 of the ship 9 approaches a specific value, or a parameter related to a value for estimating the set value. In the present embodiment, the setting parameter is, for example, the rotation speed (unit: rpm) of the propeller 13 that is set for the governor by the crew from the control console 15.

[0034] The setting parameter acquisition unit 1611 acquires setting parameter data indicating the value of the rotation speed set by the crew from the control stand 15.

[0035] The realization parameter acquisition unit 1612 acquires realization parameter data indicating the values ​​of the realization parameters. The realization parameters are parameters related to the value of the output achieved by the propeller 13 of the ship 9, or parameters related to values ​​for estimating the value of the output. In this embodiment, the realization parameters are parameters related to the weather or sea conditions that the ship 9 experiences while sailing, and specifically, are wind speed (unit: m / s), wind direction (unit: azimuth), wave height (unit: m), wave direction (unit: azimuth), wave period (unit: s), tidal speed (unit: knot), and tidal direction (unit: azimuth). However, the influence of the values ​​of these weather or sea condition parameters on the output achieved by the propeller 13 varies depending on the draft and direction of travel of the ship 9. Therefore, in this embodiment, the realization parameters also include the draft (unit: cm) and direction of travel (unit: azimuth).

[0036] The realized parameter acquisition unit 1612 acquires realized parameter data indicating the values ​​of the realized parameters from a measuring device (not shown in FIG. 1 etc.) mounted on the ship 9. Furthermore, the realized parameter acquisition unit 1612 acquires realized parameter data indicating the value of the draft, among the realized parameters, from the input device 1604 operated by the crew. Furthermore, the realized parameter acquisition unit 1612 acquires realized parameter data indicating the value of the heading, among the realized parameters, from the pilot stand 15. Note that if measuring devices that measure the draft and heading are mounted on the ship 9, the realized parameter acquisition unit 1612 may acquire realized parameter data indicating these values ​​from the measuring device.

[0037] The position acquisition unit 1613 acquires position data indicating the position (latitude and longitude) of the ship 9 on the Earth from a measuring device (not shown in FIG. 1 etc.) mounted on the ship 9 .

[0038] The energy consumption acquisition unit 1614 acquires energy consumption data indicating the amount of energy consumed by the ship 9 while sailing from a measuring device (not shown in FIG. 1 etc.) mounted on the ship 9.

[0039] The energy consumption rate calculation unit 1615 calculates the energy consumption rate from the location indicated by the location data continuously acquired by the location acquisition unit 1613 and the energy consumption indicated by the energy consumption data continuously acquired by the energy consumption acquisition unit 1614.

[0040] The moment of inertia specifying unit 1616 (an example of a specifying means) specifies the value of the moment of inertia of the flywheel according to the combination of the set parameter values ​​and the realized parameter values. In this embodiment, the moment of inertia specifying unit 1616 uses a machine learning model L to specify a reference moment of inertia (hereinafter referred to as a "reference moment of inertia M").

[0041] The machine learning model L is a machine learning model trained by machine learning using training data whose explanatory variables include the values ​​of the setting parameters and the values ​​of the realization parameters, and whose objective variable includes the value of the moment of inertia of the flywheel that reduces the energy consumption rate.

[0042] The machine learning model L is first generated using training data identified by simulations such as CFD (Computational Fluid Dynamics), and then continuously updated using training data generated using information collected while the ship 9, or ships of the same or similar type as the ship 9, are sailing in actual sea areas.

[0043] Furthermore, the moment of inertia identification unit 1616 identifies a plurality of candidate moments of inertia for adjusting the moment of inertia of the flywheel 141 based on the reference moment of inertia M identified by the machine learning model L. The process for adjusting the moment of inertia of the flywheel 141 will be described later.

[0044] The moment of inertia output unit 1617 outputs moment of inertia data indicating the moment of inertia identified by the moment of inertia identifying unit 1616 to the flywheel system 14 .

[0045] 4 is a diagram showing the configuration of the flywheel system 14. The flywheel system 14 includes a flywheel 141, a bearing 142 that rotatably holds the flywheel 141, a shaft 143 that is the rotation axis of the flywheel 141, a bevel gear 144 attached to the head of the shaft 143, a bevel gear 145 that meshes with the bevel gear 144, a shaft 146 to which the bevel gear 145 is attached at its head, a transmission 147 that can change the rotational speed of the shaft 146 relative to the rotational speed of the propeller shaft 12 while transmitting the rotational force of the propeller shaft 12 to the shaft 146, and a controller 148 that changes the gear ratio of the transmission 147 (i.e., the power transmission rate between the flywheel 141 and the propeller shaft 12).

[0046] The flywheel 141 is a disk-shaped member that rotates in conjunction with the rotation of the propeller shaft 12 and increases the moment of inertia of the propeller shaft 12 , thereby smoothing the rotation speed of the propeller shaft 12 .

[0047] In this embodiment, the rotation axis of the flywheel 141 is vertical when the vessel 9 is stationary on the water. When the flywheel 141 rotates around the vertical axis, the gyro effect suppresses rotation around an axis in the fore-and-aft direction of the vessel 9 (rolling) and rotation around an axis in the left-and-right direction of the vessel 9 (pitching), but does not suppress rotation around an axis in the vertical direction (yawing). As a result, the rolling of the vessel 9 is suppressed without impeding steering of the vessel 9.

[0048] The bearing 142 is a bearing having a plurality of rolling elements arranged in a ring shape so as to contact the outer edge of the lower surface of the flywheel 141 .

[0049] The bevel gears 144 and 145 play a role in transmitting power between the shafts 143 and 146 whose rotation axes are in different directions.

[0050] The transmission 147 is preferably a continuously variable transmission, but may be a non-continuously variable transmission.

[0051] The controller 148 stores data indicating the correspondence between the moment of inertia of the flywheel 141, i.e., the moment of inertia of the propeller shaft 12 that rotates in conjunction with the flywheel 141 via the transmission 147, and the gear ratio of the transmission 147. The controller 148 also receives inertia moment data output from the inertia moment output unit 1617 of the terminal device 16. The controller 148 then controls the transmission 147 so that the gear ratio of the transmission 147 corresponds to the value indicated by the inertia moment data received from the terminal device 16.

[0052] The controller 148 and the transmission 147 that operates under the control of the controller 148 constitute an inertia moment changing mechanism that changes the inertia moment of the flywheel 141 .

[0053] 5 is a diagram showing the data configuration of the log table stored in the storage unit 1610 of the terminal device 16. The log table is a data table for recording, in chronological order, the values ​​of the setting parameters continuously acquired by the setting parameter acquisition unit 1611, the values ​​of the realization parameters continuously acquired by the realization parameter acquisition unit 1612, the moment of inertia data continuously output by the moment of inertia identification unit 1616 to the controller 148 of the flywheel system 14, and the energy consumption rate data indicating the energy consumption rate continuously calculated by the energy consumption rate calculation unit 1615 while the ship 9 is sailing.

[0054] The log table first has a "period" field that stores data indicating a period. In this embodiment, the "period" field of the log table stores data such as "December 1, 2023, 0:00 to December 1, 2023, 0:05." In this embodiment, the length of the period indicated by the data stored in the "period" field of each data record included in the log table is assumed to be constant (for example, 5 minutes).

[0055] The log table also has a "setting parameters" field that stores setting parameter data. In this embodiment, the setting parameters include only the rotation speed of the propeller 13, as described above. Therefore, the "setting parameters" field of the log table includes only a "rotation speed" subfield that stores data indicating the rotation speed of the propeller 13.

[0056] The log table also has an "Realized Parameters" field that stores realized parameter data. In this embodiment, the realized parameters include wind speed, wind direction, wave height, wave direction, wave period, tide speed, tide direction, draft, and direction of travel, as described above. Therefore, the "Realized Parameters" field of the log table includes a "Wind Speed" subfield, a "Wind Direction" subfield, a "Wave Height" subfield, a "Wave Direction" subfield, a "Wave Period" subfield, a "Tide Speed" subfield, a "Tide Direction" subfield, a "Draft" subfield, and a "Direction of Travel" subfield that store data indicating these values.

[0057] The log table also has a “moment of inertia” field that stores the moment of inertia data output by the moment of inertia output unit 1617 .

[0058] The log table also has an “energy consumption rate” field that stores energy consumption rate data indicating the energy consumption rate calculated by the moment of inertia identification unit 1616 .

[0059] The timing and time intervals at which the setting parameter acquisition unit 1611 acquires the setting parameter data, the timing and time intervals at which the realization parameter acquisition unit 1612 acquires each piece of realization parameter data, the timing and time intervals at which the moment of inertia output unit 1617 outputs the moment of inertia data, and the timing and time intervals at which the energy consumption rate calculation unit 1615 calculates the energy consumption rate may be different. In this case, the terminal device 16 calculates a representative value (e.g., average value) of the values ​​indicated by the data acquired during the period indicated by the data stored in the "period" field of the log table, for the data corresponding to each field in the log table, and stores data indicating the calculated representative value in the log table.

[0060] Next, an operation for adjusting the moment of inertia of the flywheel 141 performed by the system 1 while the ship 9 is sailing will be described.

[0061] First, when the ship 9 departs from the port where it has been anchored, the terminal device 16 continuously outputs inertia moment data indicating an inertia moment of "0" to the flywheel system 14. In accordance with the inertia moment data received from the terminal device 16, the flywheel system 14 maintains a state in which the propeller shaft 12 and the shaft 146 are disconnected so that the gear ratio of the transmission 147 becomes 0. In this state, the main propulsion engine 11 increases the rotation speed (unit: rpm) of the propeller shaft 12 under the control of the governor until it reaches the set value.

[0062] When the rotation speed of the propeller shaft 12 reaches the set value, the moment of inertia identification unit 1616 of the terminal device 16 inputs explanatory variables including the value indicated by the set parameter data stored in the latest data record of the log table (Figure 5) and the value indicated by the realized parameter data into the machine learning model L, and identifies the value indicated by the moment of inertia data output as the objective variable from the machine learning model L as the reference moment of inertia M.

[0063] Next, the moment of inertia specifying unit 1616 instructs the moment of inertia output unit 1617 to sequentially output moment of inertia data indicating gradually increasing moment of inertia values ​​from 0 to the reference moment of inertia M. In accordance with the instruction of the moment of inertia specifying unit 1616, the moment of inertia output unit 1617 sequentially outputs moment of inertia data indicating gradually increasing moment of inertia values ​​to the flywheel system 14.

[0064] The controller 148 of the flywheel system 14 controls the transmission 147 in accordance with the moment of inertia data received from the terminal device 16 so that the gear ratio of the transmission 147 gradually increases from 0. As a result, the flywheel 141 begins to rotate in conjunction with the rotation of the propeller shaft 12, and the rotation speed (unit: rpm) of the flywheel 141 gradually increases. Then, when the moment of inertia data received by the flywheel system 14 from the terminal device 16 indicates the reference moment of inertia M, the flywheel 141 rotates in conjunction with the rotation of the propeller shaft 12 at a gear ratio corresponding to the reference moment of inertia M, and its rotation speed becomes approximately constant.

[0065] Next, the moment of inertia specifying unit 1616 performs an operation for adjusting the moment of inertia. Specifically, the moment of inertia specifying unit 1616 first instructs the moment of inertia output unit 1617 to continuously output, for a certain period of time, moment of inertia data indicating different moment of inertia values, as shown in the following example.

[0066] First period (5 minutes): Reference moment of inertia M Second period (5 minutes): Candidate moment of inertia (M + 10m) obtained by adding a predetermined amount m x 10 to the reference moment of inertia M Third period (5 minutes): Candidate moment of inertia (M + 20m) obtained by adding a predetermined amount m x 20 to the reference moment of inertia M Fourth period (10 minutes): Candidate moment of inertia (M + 30m) obtained by adding a predetermined amount m x 30 to the reference moment of inertia M Fifth period (5 minutes): Candidate moment of inertia (M + 20m) obtained by adding a predetermined amount m x 20 to the reference moment of inertia M Sixth period (5 minutes): Candidate moment of inertia (M + 10m) obtained by adding a predetermined amount m x 10 to the reference moment of inertia M Seventh period (5 minutes): Reference moment of inertia M Eighth period (5 minutes): Candidate moment of inertia (M - 10m) obtained by subtracting a predetermined amount m x 10 from the reference moment of inertia M Ninth period (5 minutes): Candidate moment of inertia (M-20m) obtained by subtracting a predetermined amount m x 20 from the reference moment of inertia M Tenth period (10 minutes): Candidate moment of inertia (M-30m) obtained by subtracting a predetermined amount m x 30 from the reference moment of inertia M Eleventh period (5 minutes): Candidate moment of inertia (M-20m) obtained by subtracting a predetermined amount m x 20 from the reference moment of inertia M Twelfth period (5 minutes): Candidate moment of inertia (M-10m) obtained by subtracting a predetermined amount m x 10 from the reference moment of inertia M

[0067] Next, the moment of inertia identification unit 1616 reads the data stored in the "energy consumption rate" field of the data record corresponding to the above-mentioned first to twelfth periods in the log table (Figure 5), and identifies the minimum value of the energy consumption rate indicated by that data.

[0068] 6 illustrates a graph showing the relationship between the moment of inertia and the energy consumption rate for each of the first to twelfth periods. In the graph of FIG. 6, the energy consumption rate corresponding to the candidate moment of inertia (M+10m) is at a minimum. The operation of the moment of inertia determination unit 1616 will be described below using the case in which the energy consumption rate corresponding to the candidate moment of inertia (M+10m) is at a minimum, as shown in FIG. 6.

[0069] Next, the moment of inertia specifying unit 1616 instructs the moment of inertia output unit 1617 to continuously output, for a certain period of time, moment of inertia data indicating different moment of inertia values, as exemplified below.

[0070] 13th period (5 minutes): Candidate reference moment of inertia (M + 10m) 14th period (5 minutes): Candidate moment of inertia (M + 13m) obtained by adding a predetermined amount m x 3 to the candidate reference moment of inertia (M + 10m) 15th period (5 minutes): Candidate moment of inertia (M + 16m) obtained by adding a predetermined amount m x 6 to the candidate reference moment of inertia (M + 10m) 16th period (10 minutes): Candidate moment of inertia (M + 19m) obtained by adding a predetermined amount m x 9 to the candidate reference moment of inertia (M + 10m) 17th period (5 minutes): Candidate moment of inertia (M + 16m) obtained by adding a predetermined amount m x 6 to the candidate reference moment of inertia (M + 10m) 18th period (5 minutes): Candidate moment of inertia (M + 13m) obtained by adding a predetermined amount m x 3 to the candidate reference moment of inertia (M + 10m) 19th period (5 minutes): Candidate reference moment of inertia (M + 10m) 20th period (5 minutes): Candidate moment of inertia (M + 7m) obtained by subtracting a predetermined amount m × 3 from the candidate reference moment of inertia (M + 10m) 21st period (5 minutes): Candidate moment of inertia (M + 4m) obtained by subtracting a predetermined amount m × 6 from the candidate reference moment of inertia (M + 10m) 22nd period (10 minutes): Candidate moment of inertia (M + m) obtained by subtracting a predetermined amount m × 9 from the candidate reference moment of inertia (M + 10m) 23rd period (5 minutes): Candidate moment of inertia (M + 4m) obtained by subtracting a predetermined amount m × 6 from the candidate reference moment of inertia (M + 10m) 24th period (5 minutes): Candidate moment of inertia (M + 7m) obtained by subtracting a predetermined amount m × 3 from the candidate reference moment of inertia (M + 10m)

[0071] Next, the moment of inertia identification unit 1616 reads the data stored in the "energy consumption rate" field of the data record corresponding to the above-mentioned 13th to 24th periods in the log table (Figure 5), and identifies the minimum value of the energy consumption rate indicated by that data.

[0072] 7 illustrates a graph showing the relationship between the moment of inertia and the energy consumption rate for each of the 13th to 24th periods. In the graph of FIG. 7, the energy consumption rate corresponding to the candidate moment of inertia (M+4m) is at a minimum value.

[0073] The moment of inertia identifying unit 1616 identifies the candidate moment of inertia corresponding to the minimum energy consumption rate identified as above (in the example of FIG. 7, the candidate moment of inertia is (M+4m)) as the optimal moment of inertia.

[0074] In the above example, the moment of inertia identification unit 1616 identifies the optimal moment of inertia through a two-stage process: a first stage in which a minimum value is identified from among the energy consumption rates corresponding to candidate moments of inertia that vary at 10-meter intervals; and a second stage in which a minimum value is identified from among the energy consumption rates corresponding to candidate moments of inertia that vary at 3-meter intervals. However, the process by which the moment of inertia identification unit 1616 identifies the optimal moment of inertia is not limited to this. For example, the optimal moment of inertia may be identified through only the first stage of processing, or through three or more stages of processing. Furthermore, the range of change of the candidate moment of inertia may be varied in various ways, as long as the range of change is narrower in later stages. Furthermore, the number of candidate moments of inertia used in each stage, the order in which the candidate moments of inertia are output from the moment of inertia output unit 1617, and the like may also be varied in various ways.

[0075] After identifying the optimal moment of inertia as described above, the moment of inertia identifying unit 1616 instructs the moment of inertia output unit 1617 to continuously output moment of inertia data indicating the optimal moment of inertia until a predetermined time has elapsed or until the set parameters or realized parameters show changes that satisfy predetermined conditions. As a result, the flywheel 141 rotates in conjunction with the propeller shaft 12 at a gear ratio corresponding to the optimal moment of inertia.

[0076] After identifying the optimal moment of inertia, the moment of inertia identification unit 1616 repeats the above-described operation for adjusting the moment of inertia when a predetermined time has elapsed or when the setting parameters or realization parameters show changes that satisfy predetermined conditions.

[0077] Each time the moment of inertia identification unit 1616 identifies an optimal moment of inertia, it generates training data that includes, as explanatory variables, the values ​​(e.g., average values) of the setting parameters and the values ​​(e.g., average values) of the realized parameters for the period during which data was collected to identify the optimal moment of inertia (the periods exemplified by the first period to the 24th period described above), and that uses the identified optimal moment of inertia value as the objective variable, and stores this data in the memory unit 1610.

[0078] The terminal device 16 transmits the teacher data stored as described above to the server device 18 via the satellite communication unit 17, for example, every time a predetermined time period has elapsed.

[0079] The server device 18 receives teacher data from the terminal device 16 installed on the ship 9, and also receives teacher data similar to the teacher data received from the terminal device 16 from terminal devices similar to the terminal device 16 installed on each of ships of the same or similar type as the ship 9. The server device 18 updates the machine learning model L using teacher data generated based on information acquired while each of the multiple ships is sailing in the actual sea area, for example, by having a processor process data in accordance with a program persistently stored in memory. The server device 18 transmits the updated machine learning model L or machine learning model data indicating the parameters of the machine learning model L to the terminal device 16 on the ship 9 and the terminal devices of ships of the same or similar type as the ship 9.

[0080] The terminal device 16 updates the stored machine learning model L using machine learning model data transmitted from the server device 18 via the satellite communication unit 17.

[0081] As described above, according to the system 1, the moment of inertia of the flywheel 141 is adjusted so as to reduce the energy consumption rate during the navigation of the vessel 9. As a result, the amount of energy consumption required for the navigation of the vessel 9 is reduced compared to when such adjustment is not made.

[0082] [Modifications] The above-described embodiment can be modified in various ways. Examples of such modifications are shown below. Note that two or more of the above-described embodiment and the following modifications may be combined as appropriate.

[0083] (1) In the above-described embodiment, the number of flywheels 141 is one. However, the flywheel system 14 may include two or more flywheels 141. In this case, the flywheel system 14 may change the power transmission ratio between the flywheel 141 and the propeller shaft 12 for each of the two or more flywheels 141. For example, the flywheel system 14 may include a transmission 147 corresponding to each of the two or more flywheels 141, and each of the two or more transmissions 147 may change its gear ratio under the control of the controller 148. Furthermore, some of the two or more transmissions 147 may separate the propeller shaft 12 from the flywheel 141, and the number of flywheels 141 that rotate in conjunction with the propeller shaft 12 may be changed, thereby changing the power transmission ratio between the entire two or more flywheels 141 and the propeller shaft 12.

[0084] (2) In the above-described embodiment, the inertia moment change mechanism that changes the inertia moment of the flywheel 141 is configured by the controller 148 and the transmission 147 that operates under the control of the controller 148. The transmission 147 changes the power transmission rate between the flywheel 141 and the propeller shaft 12, thereby changing the inertia moment of the flywheel 141.

[0085] The method by which the flywheel system 14 changes the moment of inertia of the flywheel 141 is not limited to the method of changing the power transmission rate between the flywheel 141 and the propeller shaft 12 .

[0086] For example, the mass of the flywheel 141 may be changed to change the moment of inertia of the flywheel 141 .

[0087] Fig. 8 is a diagram showing the configuration of a flywheel system 14 that changes the mass of a flywheel 141. The flywheel 141 of the flywheel system 14 shown in Fig. 8 has an accommodation space inside. The flywheel system 14 shown in Fig. 8 also includes an injection and suction device 149 that injects and suctions a filler into the accommodation space of the flywheel 141 and changes the amount of filler accommodated in the accommodation space of the flywheel 141. The filler may be any of a fluid, powder, granular material, etc., as long as it is a substance with flowability that can be injected and suctioned by the injection and suction device 149.

[0088] The controller 148 controls the injection and suction device 149 to inject or suction the filler so that a filling amount corresponding to the value of the moment of inertia indicated by the moment of inertia data received from the terminal device 16 is accommodated in the flywheel 141.

[0089] Alternatively, the flywheel 141 may have a weight that moves in the radial direction, and the moment of inertia of the flywheel 141 may be changed by changing the position of the weight in the radial direction.

[0090] FIG. 9 is a diagram showing the configuration of a flywheel 141 included in a flywheel system 14 that changes the radial position of a weight carried by the flywheel 141. The flywheel 141 shown in FIG. 9 includes a main body 1411, which is a disk-shaped member, multiple rails 1412 extending radially from a rotation axis (shaft 143) of the main body 1411, and weights 1413 attached to each of the multiple rails 1412 and moving on the rails 1412. For example, the rails 1412 are rods with threads cut into their surfaces. The weights 1413 are blocks with through holes with threaded grooves cut into their inner surfaces, and the rails 1412 are screwed into the through holes. The flywheel 141 includes a motor (not shown) that drives each of the multiple rails 1412 to rotate around its radial axis. The controller 148 then controls the direction and amount of rotation of the motor so that the weight 1413 moves to a position according to the value of the moment of inertia indicated by the moment of inertia data received from the terminal device 16 .

[0091] Fig. 9(A) shows a state in which the weight 1413 is farthest from the rotation axis (shaft 143) of the main body 1411, and Fig. 9(B) shows a state in which the weight 1413 is closest to the rotation axis (shaft 143) of the main body 1411. The flywheel 141 in the state shown in Fig. 9(A) has a larger moment of inertia than the flywheel 141 in the state shown in Fig. 9(B).

[0092] It should be noted that the method for changing the radial position of the weight 1413 is not limited to the above-described method of rotating the threaded rail 1412. For example, the weight 1413 may be configured to move freely on the rail 1412 under the control of the controller 148.

[0093] (3) In the above-described embodiment, the flywheel system 14 includes an inertia moment changing mechanism that changes the inertia moment of the flywheel 141. In a case where the flywheel system 14 does not include such an inertia moment changing mechanism, for example, a system configured by the server device 18 may estimate the inertia moment of the flywheel 141 that reduces energy consumption over the entire use period of the vessel 9. Note that the entire use period of the vessel 9 refers to the period from when the vessel 9 is put into service until it is scrapped.

[0094] Fig. 10 is a diagram showing the configuration of a flywheel system 14 having a flywheel 141 with an optimal moment of inertia estimated by a system according to this modification. In this modification, the moment of inertia of the flywheel 141 is not changed. Therefore, as shown in Fig. 10, the flywheel system 14 according to this modification does not include a shaft 146, a transmission 147, or a controller 148. In addition, the bevel gear 145 included in the flywheel system 14 according to this modification is attached to the propeller shaft 12 rather than to the shaft 146.

[0095] 11 is a diagram showing the hardware configuration of the server device 18. The hardware of the server device 18 is a computer for the server device. That is, the server device 18 includes a processor 1801 that performs various data processing according to a program, a memory 1802 that stores various data including the program executed by the processor 1801, and a communication interface 1803 that performs data communication with external devices.

[0096] The memory 1802 stores data persistently, and includes volatile memory that stores data persistently only while power is being supplied, and nonvolatile memory that stores data persistently even when power is cut off. For example, programs executed by the processor 1801 are stored in the nonvolatile memory of the memory 1802. Furthermore, for example, data that is temporarily generated when the processor 1801 performs various data processing according to the programs is stored in the volatile memory of the memory 1802.

[0097] Fig. 12 is a diagram showing the functional configuration of server device 18. That is, a processor 1801 of a computer (see Fig. 11), which is the hardware of server device 18, executes various data processes in accordance with a program for server device 18 according to this modification, thereby realizing a data processing system including the components shown in Fig. 12. The functional configuration of server device 18 shown in Fig. 12 will be described below.

[0098] The storage unit 1810 stores various types of data.

[0099] The sailing schedule estimation unit 1811 estimates the sailing schedule for the entire service period of the ship 9 that will be manufactured from now on. Here, the sailing schedule of a ship means a combination of the route that the ship will travel (sailing route), the time when the ship will travel along that sailing route (sailing period), and the amount of cargo when the ship travels along that sailing route at that sailing period.

[0100] The sailing schedule estimation unit 1811 estimates the sailing schedule of the ship 9 for the entire period of use based on sailing schedule data showing past sailing schedules for ships of the same type as or similar to the ship 9.

[0101] The setting parameter estimation unit 1812 estimates the values ​​of the setting parameters for the entire use period of the ship 9 based on the sailing schedule of the ship 9 estimated by the sailing schedule estimation unit 1811.

[0102] The realized parameter estimation unit 1813 estimates the values ​​of realized parameters for the entire use period of the ship 9 based on the sailing schedule of the ship 9 estimated by the sailing schedule estimation unit 1811.

[0103] The realized parameter estimation unit 1813 obtains estimated values ​​of realized parameters, for example, wind speed, wind direction, wave height, wave direction, wave period, tide speed, and tide direction, which are meteorological or sea conditions among the realized parameters, that the ship 9 will encounter in the future when navigating the actual sea area according to the navigation schedule, from an external server device that provides estimated information on future meteorological and sea conditions.

[0104] Furthermore, the realized parameter estimation unit 1813 estimates the values ​​of the draft and the direction of travel among the realized parameters from the sailing schedule of the ship 9 .

[0105] The energy consumption estimation unit 1814 estimates a change in energy consumption over the entire usage period of the ship 9 in response to a change in the value of the moment of inertia of the flywheel 141, in accordance with a combination of the values ​​of the setting parameters over the entire usage period of the ship 9 estimated by the setting parameter estimation unit 1812 and the values ​​of the realized parameters over the entire usage period of the ship 9 estimated by the realized parameter estimation unit 1813. Note that the flywheel 141 here is not yet installed on the ship 9 and is still in the design stage.

[0106] The energy consumption estimation unit 1814, for example, uses a machine learning model (hereinafter referred to as the "machine learning model N") to estimate the energy consumption over the entire usage period of the ship 9 according to various combinations of values ​​of the setting parameters, the realization parameters, and the moment of inertia of the flywheel.

[0107] The machine learning model N is a machine learning model trained by machine learning using training data whose explanatory variables include values ​​of setting parameters, values ​​of realization parameters, and a value of the moment of inertia of the flywheel, and whose objective variable includes an energy consumption rate. That is, the machine learning model N is a machine learning model generated using training data whose explanatory variables include values ​​of setting parameters, values ​​of realization parameters, and a value of the moment of inertia of the flywheel, and whose objective variable includes an energy consumption rate when the ship is sailing under conditions in which an output torque corresponding to the values ​​of the setting parameters included in the explanatory variables is applied to the propeller shaft, a load corresponding to the values ​​of the realization parameters included in the explanatory variables is applied to the propeller, and the value of the moment of inertia of the flywheel is the value of the moment of inertia included in the explanatory variables.

[0108] When the server device 18 acquires newly generated teacher data in association with a new navigation of a ship in an actual sea area, the server device 18 uses the teacher data to update the machine learning model N. The server device 18 generates and updates the machine learning model N through data processing performed by the processor 1801 in accordance with the program stored in the memory 1802.

[0109] The energy consumption estimation unit 1814 multiplies the energy consumption rate output as the objective variable from the machine learning model N by the length of time during which a combination of the values ​​of the setting parameters, the values ​​of the realization parameters, and the value of the moment of inertia of the flywheel, which are included in the explanatory variables input to the machine learning model N, continues during the navigation of the ship 9, to calculate the energy consumption of the ship 9 for that period. Then, the server device 18 adds up the energy consumption of the ship 9 over the entire usage period of the ship 9, and estimates the energy consumption of the ship 9 over the entire usage period of the ship 9.

[0110] The energy consumption estimation unit 1814 estimates the energy consumption over the entire period of use of the vessel 9 as described above for various values ​​of the moment of inertia.

[0111] The moment of inertia specifying unit 1815 (an example of a specifying means) specifies the minimum energy consumption among the energy consumptions over the entire usage period of the vessel 9 estimated by the energy consumption estimation unit 1814 for various values ​​of the moment of inertia, and specifies the value of the moment of inertia corresponding to the specified energy consumption as the optimal moment of inertia value of the flywheel 141 to be mounted on the vessel 9. The moment of inertia specifying unit 1815 transmits moment of inertia data indicating the specified optimal moment of inertia value of the flywheel 141 to a terminal device used by a user (e.g., a designer of the vessel 9). Note that if the server device 18 has a built-in display device or if a display device is connected to the server device 18, the server device 18 may display the optimal moment of inertia value of the flywheel 141 specified by the moment of inertia specifying unit 1815 on the display device.

[0112] In the above description, the system according to this modification is configured by the server device 18, but the system according to this modification may be configured by a data processing device other than the server device 18. Furthermore, the system according to this modification may be configured by a collection of multiple data processing devices that operate in conjunction with each other.

[0113] (4) In the above-described embodiment, the setting parameter is the set rotation speed of the propeller shaft (i.e., the propeller) (i.e., the command rotation speed for the main propulsion engine), but the setting parameter may be of any type as long as it is a parameter related to a value that is set so that the output of the main propulsion engine approaches a specific value, or a parameter related to a value for estimating that set value. Examples of setting parameters include the set rotation speed of the propeller shaft (i.e., the number of rotations per unit time of the propeller) (unit: rpm), as well as the following:

[0114] Output torque of the main propulsion engine (unit: kN m) Output horsepower of the main propulsion engine (unit: kW) Ship speed (unit: knot) Amount of energy supplied to the main propulsion engine per unit time (if the main propulsion engine is an internal combustion engine, unit: ton / day, or rack amount indicating the position of the adjuster (rack) for the amount of fuel oil injection) Ship thrust (kN)

[0115] Two or more of these parameters may be used as the setting parameters.

[0116] These setting parameters may also include parameters related to a representative value of a plurality of values ​​of the same parameter measured over a period of time equal to or longer than a certain length of time. For example, instead of the set value of the ship's speed, a representative value such as the average or median value of the ship's side continuously measured may be used as the setting parameter as an estimated value of the ship's speed.

[0117] (5) In the above-described embodiment, the realized parameters are wind speed (unit: m / s), wind direction (unit: azimuth), wave height (unit: m), wave direction (unit: azimuth), wave period (unit: s), tide speed (unit: knot), tide direction (unit: azimuth), draft (unit: cm), and direction of travel (unit: azimuth). However, the realized parameters may be of any type as long as they are parameters relating to the value of the output realized by the ship's propeller or parameters relating to values ​​for estimating the value of that output. Examples of realized parameters include wind speed, wind direction, wave height, wave direction, wave period, tide speed, tide direction, draft, and direction of travel, as well as the following:

[0118] Propeller revolutions per unit time (unit: rpm) Output torque of the main propulsion engine (kN m) Output horsepower of the main propulsion engine (unit: kW) Ship speed (unit: knot) Amount of ship rolling (unit: degree) Amount of ship pitching (unit: degree) Amount of ship yaw (unit: degree) Flow field around the propeller (m / s) Sea margin (increase in horsepower when sailing in actual seas compared to when sailing in calm waters) (unit: kW) Revolution margin (decrease in revolutions when sailing in actual seas compared to when sailing in calm waters) (unit: rpm) Propeller slip (decrease in ship speed when sailing in actual seas compared to when sailing in calm waters) (unit: knot)

[0119] It should be noted that although there are parameters with the same name as both the setting parameter and the realization parameter, such as "propeller revolutions per unit time," they are different. For example, the propeller revolutions per unit time (rpm) used as the setting parameter is the set rpm, while the rpm used as the realization parameter is the rpm that is actually measured.

[0120] Two or more of these parameters may be used as realization parameters.

[0121] These realization parameters may also include parameters related to the amplitude and period of multiple values ​​of the same parameter measured over a certain period of time. For example, the amplitude (unit: rpm) and period (unit: s) of the rotation speed that changes over time may be used as the setting parameters.

[0122] (6) The units shown for the setting parameters and the realization parameters described above are merely examples, and other units of the same type may be used. For example, instead of "knots," "km / h" or the like may be used as the unit of ship speed.

[0123] (7) In the above-described embodiment, the rotation axis of the flywheel 141 is vertical when the vessel 9 is stationary on the water. However, the direction of the rotation axis of the flywheel 141 is not limited to this. For example, the rotation axis of the flywheel 141 may be inclined at a predetermined angle with respect to the vertical direction when the vessel 9 is stationary on the water. Furthermore, the rotation axis of the flywheel 141 may be parallel to the extension direction of the propeller shaft 12. Furthermore, the rotation axis of the flywheel 141 may be the propeller shaft 12.

[0124] However, when the rotation axis of the flywheel 141 is parallel to the extension direction of the propeller shaft 12, the gyroscopic effect caused by the rotation of the flywheel 141 suppresses rotation around an axis in the left-right direction of the ship 9 (pitching) and rotation around an axis in the vertical direction (yawing), but does not suppress rotation around an axis in the fore-aft direction of the ship 9 (rolling). As a result, while steering of the ship 9 is somewhat hindered, rolling of the ship 9 is not suppressed. Therefore, it is generally desirable that the rotation axis of the propeller shaft 12 and the rotation axis of the flywheel 141 are non-parallel.

[0125] (8) In the above-described embodiment, the moment of inertia identification unit 1616 identifies the reference moment of inertia M using a machine learning model L. The method for identifying the reference moment of inertia M is not limited to the method using a machine learning model.

[0126] Furthermore, in the above-described embodiment, the energy consumption estimation unit 1814 estimates the energy consumption over the entire usage period of the vessel 9 according to various combinations of the setting parameters, the realization parameters, and the moment of inertia of the flywheel, using the machine learning model N. The method for estimating the energy consumption over the entire usage period of the vessel 9 is not limited to the method using the machine learning model.

[0127] For example, a statistical method such as multivariate analysis may be used to identify a calculation formula for calculating the moment of inertia that results in the minimum energy consumption rate, using the values ​​of the set parameters and the realized parameters as variables.The moment of inertia identification unit 1616 may then use this calculation formula to identify the reference moment of inertia M, and the energy consumption estimation unit 1814 may use this calculation formula to estimate the energy consumption of the ship 9 over the entire usage period.

[0128] 1...system, 9...ship, 11...main propulsion engine, 12...propeller shaft, 13...propeller, 14...flywheel system, 15...control platform, 16...terminal device, 17...satellite communication unit, 18...server device, 141...flywheel, 142...bearing, 143...shaft, 144...bevel gear, 145...bevel gear, 146...shaft, 147...transmission, 148...controller, 149...injection and suction device, 1411...main body, 1412...rail, 1413...weight, 1601...processor, 1602...memory, 1603...display, 1604...input device, 1605...input / output Force interface, 1610...storage unit, 1611...setting parameter acquisition unit, 1612...realization parameter acquisition unit, 1613...position acquisition unit, 1614...energy consumption acquisition unit, 1615...energy consumption rate calculation unit, 1616...moment of inertia determination unit, 1617...moment of inertia output unit, 1801...processor, 1802...memory, 1803...communication interface, 1810...storage unit, 1811...navigation schedule estimation unit, 1812...setting parameter estimation unit, 1813...realization parameter estimation unit, 1814...energy consumption estimation unit, 1815...moment of inertia determination unit.

Claims

1. A program for causing a computer to execute a process for determining the value of the moment of inertia of a flywheel that rotates in conjunction with the rotation of the propeller shaft of a ship, based on a combination of the value of a setting parameter, which is a parameter related to a value that is set so that the output of the ship's main propulsion engine approaches a specific value or a parameter related to a value for estimating that set value, and the value of a realization parameter, which is a parameter related to the value of the output realized by the ship's propeller or a parameter related to a value for estimating that output value.

2. The program according to claim 1, for causing the computer to execute a process of inputting explanatory variables including the values ​​of the setting parameters and the values ​​of the realization parameters while the ship is sailing into a machine learning model trained by machine learning using training data that includes the values ​​of the setting parameters and the values ​​of the realization parameters as explanatory variables and the value of the moment of inertia that reduces the energy consumption rate during sailing of the ship as a dependent variable in a process of identifying the value of the moment of inertia, and obtaining the value of the moment of inertia output from the machine learning model as a dependent variable as the value of the moment of inertia corresponding to the combination of the values ​​of the setting parameters and the values ​​of the realization parameters.

3. The program according to claim 1, wherein the setting parameters include one or more of the number of revolutions per unit time of the propeller, the output torque of the main propulsion engine, the output horsepower of the main propulsion engine, the vessel speed, the amount of energy supplied per unit time to the main propulsion engine, and the thrust of the vessel.

4. The program according to claim 1, wherein the setting parameters include parameters relating to representative values ​​of a plurality of values ​​of the same parameter measured during a period of time equal to or longer than a certain length of time.

5. The program according to claim 1, wherein the realization parameters include one or more of the rotation speed per unit time of the propeller, the output torque of the main propulsion engine, the output horsepower of the main propulsion engine, the ship speed, the wind speed and direction of the wind that the ship receives, the height, direction and period of waves that the ship receives, the speed and direction of the current that the ship receives, the amount of rolling motion of the ship, the amount of pitching motion of the ship, the amount of yaw motion of the ship, the flow field around the propeller, the sea margin of the ship, the rotation speed margin of the ship, and the propeller slip of the ship.

6. The program according to claim 1, wherein the realized parameters include parameters relating to amplitude and period indicated by multiple values ​​of the same parameter measured during a period of time equal to or longer than a certain length.

7. A system comprising: a flywheel system having a flywheel that rotates with the rotation of a ship's propeller shaft; and an inertia moment changing mechanism that changes the inertia moment of the flywheel; and a data processing system that specifies the value of the inertia moment that the flywheel should take, wherein the data processing system has a specifying means for specifying the value of the inertia moment that the flywheel should take in accordance with a combination of a parameter related to a value that is set so that the output output of the ship's main propulsion engine approaches a specific value or a parameter related to a value for estimating said set value, and a parameter related to a parameter related to a value of the output that the ship's propeller is achieving or a parameter related to a value for estimating said output value, and the inertia moment changing mechanism changes the inertia moment of the flywheel so that the value of the inertia moment of the flywheel approaches the value of the inertia moment specified by the data processing system.

8. The system according to claim 7, wherein the inertia moment changing mechanism changes the power transmission ratio between each of the two or more flywheels and the propeller shaft.

9. The system according to claim 7, wherein the flywheel has an accommodation space, and the inertia moment changing mechanism changes the amount of filler filled in the accommodation space.

10. The system according to claim 7, wherein the rotation axis of the propeller shaft and the rotation axis of the flywheel are non-parallel.

11. The system according to claim 7, wherein the rotation axis of the flywheel is vertical when the vessel is stationary on the water.

12. A ship comprising: a flywheel system having a flywheel that rotates with the rotation of a propeller shaft and an inertia moment changing mechanism that changes the inertia moment of the flywheel; and a data processing system that specifies the value of the inertia moment that the flywheel should take, wherein the data processing system has a specifying means for specifying the value of the inertia moment that the flywheel should take in accordance with a combination of a parameter related to a value that is set so that the output output of the main propulsion engine of the ship approaches a specific value or a parameter related to a value for estimating the set value, and a parameter related to a parameter related to the value of the output that the propeller of the ship is achieving or a parameter related to a value for estimating the value of the output, and the inertia moment changing mechanism changes the inertia moment of the flywheel so that the value of the inertia moment of the flywheel approaches the value of the inertia moment specified by the data processing system.

13. A program for causing a computer to execute a process of generating or updating a machine learning model using training data including, as explanatory variables, the value of a setting parameter, which is a parameter related to a value that is set so that the output of a ship's main propulsion engine approaches a specific value or a parameter related to a value for estimating that set value, and the value of a realization parameter, which is a parameter related to a value for estimating the output value achieved by the ship's propeller or a parameter related to a value for estimating that output, and including, as a target variable, the value of the moment of inertia of a flywheel that rotates in conjunction with the rotation of the ship's propeller shaft, which reduces the energy consumption rate when the ship is sailing.

14. A program for causing a computer to execute the following processes: a process for estimating changes in energy consumption over the entire period of use of the ship according to a combination of a parameter related to a value that is set so that the output produced by the ship's main propulsion engine approaches a specific value when the value of the moment of inertia of a flywheel that rotates in accordance with the rotation of the ship's propeller shaft is changed, or a setting parameter that is a parameter related to a value for estimating the set value, and a parameter related to a value of the output realized by the ship's propeller, or a parameter related to a value for estimating the value of the output; and a process for identifying the value of the moment of inertia of the flywheel that will result in a reduction in energy consumption over the entire period of use of the ship, based on the change in energy consumption estimated in the estimation process.

15. The program described in claim 14, for causing the computer to execute a process of estimating changes in energy consumption, in which a machine learning model trained by machine learning using training data including the value of the set parameter, the value of the realized parameter, and the value of the moment of inertia as explanatory variables and including the energy consumption rate during the navigation of the ship as a dependent variable, is input with respect to each of a plurality of values ​​when the moment of inertia is changed between the plurality of values, the value of the moment of inertia, the value of the set parameter, and the value of the realized parameter as explanatory variables, and the energy consumption rate is output as a dependent variable from the machine learning model.

16. The program according to claim 14, wherein the setting parameters include one or more of the number of revolutions per unit time of the propeller, the output torque of the main propulsion engine, the output horsepower of the main propulsion engine, the vessel speed, the amount of energy supplied per unit time to the main propulsion engine, and the thrust of the vessel.

17. The program according to claim 14, wherein the setting parameters include parameters relating to representative values ​​of a plurality of values ​​of the same parameter measured during a period of time equal to or longer than a certain length of time.

18. The program according to claim 14, wherein the realization parameters include one or more of the number of revolutions per unit time of the propeller, the output torque of the main propulsion engine, the output horsepower of the main propulsion engine, the ship speed, the wind speed and direction of the wind that the ship experiences, the height, direction and period of waves that the ship experiences, the speed and direction of the current that the ship experiences, the amount of rolling motion of the ship, the amount of pitching motion of the ship, the amount of yaw motion of the ship, the flow field around the propeller, the sea margin of the ship, the rotation speed margin of the ship, and the propeller slip of the ship.

19. The program according to claim 14, wherein the realized parameters include parameters relating to amplitude and period indicated by multiple values ​​of the same parameter measured during a period of time equal to or longer than a certain length.

20. A program for causing a computer to execute a process of generating or updating a machine learning model using training data whose explanatory variables include the value of a setting parameter, which is a parameter related to a value that is set so that the output of a ship's main propulsion engine approaches a specific value or a parameter related to a value for estimating said set value, the value of a realization parameter, which is a parameter related to a value of the output realized by the ship's propeller or a parameter related to a value for estimating said output value, and the value of the moment of inertia of a flywheel that rotates in conjunction with the rotation of the ship's propeller shaft, and whose objective variable is the energy consumption rate during the navigation of the ship.

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