Rotation speed determination device, rotation speed determination method, and program

Abstract

This invention provides a rotation speed determination device, rotation speed determination method, and program that enable adherence to the planned route and fuel-efficient operation without requiring the crew to adjust the actual rotation speed of the main propulsion engine according to the weather and sea conditions at the current location. [Solution] The rotation speed determination device includes a target speed calculation unit that calculates the target speed of the ship at a shorter interval than the update cycle of the instructed speed to the ship, based on the path length between the position of the waypoint and the current position of the ship, and the difference between the target arrival time at the waypoint and the current time, and a rotation speed determination unit that determines the instructed rotation speed to the ship's main propulsion engine based on the target speed. If the path length between the position of the next waypoint and the current position is less than a first threshold, the target speed calculation unit may calculate the target speed of the ship based on the path length between the position of a waypoint after the next waypoint and the current position, and the difference between the target arrival time at the selected waypoint and the current time.

Description

Technical Field

[0001] The present invention relates to a rotation speed determination device, a rotation speed determination method, and a program.

Background Art

[0002] An Electronic Chart Display and Information System (ECDIS) that executes Weather Routing may be used so that a ship can comply with a route plan. In Weather Routing, the Electronic Chart Display and Information System determines a route using each waypoint based on a weather and sea state forecast. Further, the Electronic Chart Display and Information System notifies a crew member (navigator) of the arrival target time of each waypoint.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the update cycle for the target arrival time notified to the crew by the electronic chart display information system is long. The electronic chart display information system or the crew calculates the instructed speed to the ship based on the target arrival time with a long update cycle, but this instructed speed also has a long update cycle. If the crew adjusts the actual RPM of the main propulsion engine according to the instructed speed with a long update cycle, there is a possibility that they will not be able to adhere to the route plan and that they will consume more fuel than necessary. Therefore, the crew must frequently adjust the actual RPM of the main propulsion engine according to the weather and sea conditions at their current position, rather than according to the instructed speed with a long update cycle. Thus, if the crew does not adjust the actual RPM of the main propulsion engine according to the weather and sea conditions at their current position, there is a problem in that they cannot adhere to the route plan and operate in a fuel-efficient manner.

[0005] In view of the above circumstances, the present invention aims to provide a rotation speed determination device, a rotation speed determination method, and a program that enable adherence to the planned route and fuel-efficient operation without requiring the crew to adjust the actual rotation speed of the main propulsion engine according to the weather and sea conditions at the current location. [Means for solving the problem]

[0006] One aspect of the present invention is a rotational speed determination device comprising: a target speed calculation unit that calculates the target speed of the ship at a shorter interval than the update cycle of the instructed speed to the ship, based on the path length between the location of a waypoint and the current position of the ship, and the difference between the target arrival time to the waypoint and the current time; and a rotational speed determination unit that determines the instructed rotational speed to the main propulsion engine of the ship based on the target speed.

[0007] The above-mentioned rotational speed determination device enables adherence to the planned route and fuel-efficient operation without requiring the crew to adjust the actual rotational speed of the main propulsion engine according to the weather and sea conditions at the current location.

[0008] In one aspect of the present invention, the target ship speed calculation unit selects a waypoint after the next waypoint if the path length between the position of the next waypoint and the current position is less than a first threshold, and calculates the target ship speed of the ship based on the path length between the position of the selected waypoint and the current position, and the difference between the target arrival time at the selected waypoint and the current time.

[0009] In one aspect of the present invention, the rotation speed determination unit temporarily suspends determining the indicated rotation speed until the ship arrives at the next waypoint if the path length between the position of the next waypoint and the current position is less than a first threshold.

[0010] One aspect of the present invention further comprises a target speed determination unit that determines the target speed from within a predetermined speed range, and the rotation speed determination unit determines the indicated rotation speed based on the determined target speed.

[0011] In one aspect of the present invention, the target ship speed determination unit determines the target ship speed to be the indicated ship speed which has been overwritten by a ship speed within the ship speed range, or the indicated ship speed which has been corrected to be within the ship speed range.

[0012] In one aspect of the present invention, the target ship speed determination unit acquires the indicated ship speed from the electronic chart display information system, and the target ship speed calculation unit acquires the position of the waypoint, the current position, the target arrival time, and the current time from the electronic chart display information system.

[0013] In one aspect of the present invention, the target ship speed calculation unit obtains the position of the waypoint and the target arrival time from an input device, the current position and the current time from a satellite positioning device, and the target ship speed determination unit obtains the indicated ship speed from the input device.

[0014] In one aspect of the present invention, the target ship speed determination unit determines the ship speed range such that, when the path length between the ship's final target position and its current position is less than a second threshold, the ship arrives at the waypoint at the target arrival time, prioritizing this over the fuel consumption of the main propulsion engine.

[0015] One aspect of the present invention is a rotational speed determination method that includes the steps of: calculating a target speed for a ship at a shorter interval than the update cycle for the instructed speed to the ship, based on the path length between the location of a waypoint and the current position of the ship, and the difference between the target time of arrival at the waypoint and the current time; and determining the instructed rotational speed to the ship's main propulsion engine based on the target speed.

[0016] One aspect of the present invention is a program for causing a computer to perform the following steps: calculate the target speed of a ship at a shorter interval than the update cycle of the instructed speed to the ship, based on the path length between the location of a waypoint and the current position of the ship, and the difference between the target time of arrival at the waypoint and the current time; and determine the instructed rotational speed to the ship's main propulsion engine based on the target speed. [Effects of the Invention]

[0017] This invention makes it possible to adhere to the planned route and operate fuel-efficiently without the crew having to adjust the actual rotational speed of the main propulsion engine according to the weather and sea conditions at the current location. [Brief explanation of the drawing]

[0018] [Figure 1] This figure shows an example of the configuration of the rotational speed determination system in the first embodiment. [Figure 2] This figure shows an example of an electronic chart in the first embodiment. [Figure 3] This is a flowchart showing an example of the operation of the rotation speed determination system in the first embodiment. [Figure 4] This figure shows an example of the configuration of the rotational speed determination system in the second embodiment. [Figure 5]It is a diagram showing a configuration example of a rotational speed determination system in the third embodiment.

Embodiments for Carrying Out the Invention

[0019] Embodiments of the present invention will be described in detail with reference to the drawings. (First Embodiment) FIG. 1 is a diagram showing a configuration example of a rotational speed determination system 1 in the first embodiment. The rotational speed determination system 1 is a system that determines the rotational speed of the main propulsion engine of a ship. The rotational speed determination system 1 is mounted on a ship. The rotational speed determination system 1 includes an electronic chart display information system 2, a rotational speed determination device 3, and a main propulsion engine 4. The rotational speed determination device 3 includes a target ship speed calculation unit 31, a target ship speed determination unit 32, and a rotational speed determination unit 33.

[0020] Some or all of the functional units of the rotational speed determination device 3 are realized by a processor (computer) such as a CPU (Central Processing Unit) executing a program stored in a storage unit. The storage unit is preferably a non-volatile recording medium (non-temporary recording medium) such as a flash memory or an HDD (Hard Disk Drive). The storage unit may include a volatile recording medium such as a RAM (Random Access Memory). Some or all of the functional units of the rotational speed determination device 3 may be realized using hardware such as an LSI (Large Scale Integrated circuit) or an ASIC (Application Specific Integrated Circuit).

[0021] The electronic chart display information system 2 includes, for example, a satellite compass. The electronic chart display information system 2 measures the current position of the ship based on, for example, radio waves from artificial satellites and the current time. The current time is expressed in, for example, Coordinated Universal Time.

[0022] The electronic chart display information system 2 updates at least the position (coordinates) of each waypoint and the target time of arrival at each waypoint at a predetermined update cycle, based on the ship's current position and route plan. The update cycle is, for example, one hour. The electronic chart display information system 2 may also perform weather routing. That is, the electronic chart display information system 2 may update the position of each waypoint and the target time of arrival at each waypoint at a predetermined update cycle, based on weather and sea conditions forecasts, the ship's current position, and route plan. The electronic chart display information system 2 outputs the position of each waypoint, the ship's current position, the target time of arrival at each waypoint, and the current time to the rotation speed determination device 3 at a predetermined update cycle. The electronic chart display information system 2 may also output the indicated ship speed for each waypoint and the ship's ship speed over the ground to the rotation speed determination device 3.

[0023] Figure 2 shows an example of an electronic chart in the first embodiment. The electronic chart display information system 2 displays an electronic chart. The electronic chart includes a ship image 101 and one or more waypoint images 201. The position of the ship image 101 indicates the current position of the ship equipped with the rotation speed determination system 1. The current position is expressed, for example, using latitude and route. In the electronic chart, the indicated ship speed may be displayed near the ship image 101. One or more waypoint images 201 are arranged on the electronic chart along the route. Adjacent waypoint images 201 may be connected by arrows along the route. Near the waypoint image 201, the target time of arrival at the waypoint associated with that waypoint image 201 may be displayed.

[0024] Returning to Figure 1, let's continue the explanation of the configuration example of the rotation speed determination system 1. In this embodiment, the rotation speed determination device 3 determines the instruction rotation speed for the main propulsion engine 4 based on the instruction ship speed, the position of each waypoint, the ship's current position, the target arrival time at each waypoint, and the current time. The main propulsion engine 4 drives the shaft equipped with the main propulsion engine 4 so that the actual rotation speed of the shaft equipped with the main propulsion engine 4 is equal to the instruction rotation speed.

[0025] Next, we will explain the details of the rotation speed determination device 3. The target speed calculation unit 31 acquires the position of each waypoint, the target arrival time to each waypoint, the ship's current position, and the current time from the electronic chart display information system 2 at a predetermined update cycle (for example, 1 hour). Based on the path length "y" between the waypoint position and the ship's current position, and the difference "x" between the target arrival time to the waypoint and the current time, the target speed calculation unit 31 calculates the ship's target speed "y / x" at a shorter cycle than the update cycle for the instructed speed to the ship.

[0026] The target ship speed calculation unit 31 may select a waypoint after the next waypoint if the path length between the position of the next waypoint and the current position is less than a first threshold. The target ship speed calculation unit 31 may calculate the ship's target ship speed "y' / x'" based on the path length "y'" between the position of the selected waypoint and the current position, and the difference "x'" between the target arrival time at the selected waypoint and the current time.

[0027] In the example shown in Figure 2, the target ship speed calculation unit 31 may select a waypoint associated with waypoint image 201-2 if the path length between the waypoint associated with waypoint image 201-1 (the next waypoint) and the ship's current position is less than a first threshold. The target ship speed calculation unit 31 may calculate the ship's target ship speed "y' / x'" by performing a division operation based on the path length "y'" between the position of the waypoint associated with waypoint image 201-2 and the current position, and the difference "x'" between the target arrival time at that waypoint and the current time.

[0028] The target speed determination unit 32 acquires the indicated speed from the electronic chart display information system 2 at a predetermined update cycle. The target speed determination unit 32 acquires the target speed "y / x" from the target speed calculation unit 31. The target speed determination unit 32 may also acquire the target speed "y' / x'" from the target speed calculation unit 31.

[0029] If the acquired target speed falls within a predetermined speed range, the target speed determination unit 32 determines the acquired target speed as the target speed. If the acquired target speed does not fall within a predetermined speed range, the target speed determination unit 32 determines the target speed of the ship from within the predetermined speed range.

[0030] The central speed within the speed range may be, for example, the same speed as the indicated speed. The maximum (upper) and minimum (lower) speeds within the speed range are predetermined, for example, based on the fuel efficiency characteristics of the main propulsion engine 4. The maximum (upper) speed within the speed range may be determined, for example, as "Maximum speed = Indicated speed + (Indicated speed × Coefficient [%])". The minimum (lower) speed within the speed range may also be determined, for example, as "Minimum speed = Indicated speed - (Indicated speed × Coefficient [%])". This makes it possible to prevent an abnormal indicated speed from being determined as the target speed.

[0031] The target speed determination unit 32 may also determine the overwritten target speed as the target speed by overwriting the acquired target speed. Alternatively, the target speed determination unit 32 may also determine the corrected target speed as the target speed by correcting the acquired target speed.

[0032] The rotational speed determination unit 33 obtains the target ship speed determined based on the target ship speed "y / x" or "y' / x'" calculated by the target ship speed calculation unit 31 from the target ship speed determination unit 32. The rotational speed determination unit 33 may also obtain the target ship speed "y / x" or "y' / x'" calculated by the target ship speed calculation unit 31 as the determined target ship speed from the target ship speed calculation unit 31.

[0033] The rotational speed determination unit 33 determines the instruction rotational speed to be sent to the ship's main propulsion engine 4 based on the determined target ship speed. Based on the correspondence between the determined target ship speed and the instruction rotational speed, the rotational speed determination unit 33 outputs the instruction rotational speed associated with the determined target ship speed to the main propulsion engine 4. The correspondence between the determined target ship speed and the instruction rotational speed may be stored in advance in the rotational speed determination unit 33, for example, in the form of a lookup table.

[0034] The rotational speed determination unit 33 may also obtain the actual rotational speed of the shaft of the main propulsion engine 4 from a measuring instrument (not shown) provided on the main propulsion engine 4. The rotational speed determination unit 33 may also output the indicated rotational speed to the main propulsion engine 4 if the actual rotational speed and the indicated rotational speed do not match.

[0035] Furthermore, the rotation speed determination unit 33 may acquire the ground speed (actual ship speed) from the electronic chart display information system 2 at a predetermined period. The rotation speed determination unit 33 may also output the indicated rotation speed to the main propulsion engine 4 if the ground speed and the target ship speed do not match.

[0036] Next, we will explain an example of the operation of the rotation speed determination system 1. Figure 3 is a flowchart showing an example of the operation of the rotation speed determination system 1 in the first embodiment. The target ship speed calculation unit 31 calculates the target ship speed of the ship at a shorter cycle than the update cycle of the instructed ship speed to the ship, based on the path length between the position of the waypoint and the current position of the ship, and the difference between the target arrival time at the waypoint and the current time (step S101). The rotation speed determination unit 33 determines the instructed rotation speed to the ship's main propulsion engine 4 based on the target ship speed output from the target ship speed calculation unit 31 or the target ship speed determination unit 32 (step S102).

[0037] As described above, the target speed calculation unit 31 calculates the target speed of the ship at a shorter interval than the update cycle of the instructed speed to the ship, based on the path length between the waypoint location and the ship's current position, and the difference between the target arrival time at the waypoint and the current time. The rotation speed determination unit 33 determines the instructed rotation speed to the ship's main propulsion engine 4 based on the target speed calculated by the target speed calculation unit 31 at a short interval. The rotation speed determination unit 33 may also determine the instructed rotation speed to the ship's main propulsion engine 4 based on the target speed determined by the target speed determination unit 32, which has acquired the target speed calculated at a short interval.

[0038] This allows for adherence to the route plan displayed on the electronic chart display information system 2 and fuel-efficient operation without the crew having to adjust the actual rotation speed of the main propulsion engine 4 according to the weather and sea conditions at the current location.

[0039] Furthermore, if the rotation speed determination unit 33 is less than the first threshold, it may temporarily suspend (skip) determining the indicated rotation speed until the ship arrives at the next waypoint.

[0040] (Second Embodiment) In the second embodiment, the main difference from the first embodiment is that the ship speed range is determined based on the path length between the ship's final target position and the ship's current position. The second embodiment will be explained focusing on the differences from the first embodiment.

[0041] Figure 4 shows an example of the configuration of the rotation speed determination system 1 in the second embodiment. The target ship speed determination unit 32 acquires the instructed ship speed, the final target position, and the current position from the electronic chart display information system 2 at a predetermined update cycle.

[0042] The target speed determination unit 32 may determine a speed range that prioritizes the ship arriving at the waypoint at the target arrival time over the fuel consumption of the main propulsion engine 4, if the path length between the ship's final target position and its current position is less than a second threshold. Furthermore, the route sections in which the rotational speed determination device 3 operates in this time-priority mode may be predetermined in the route plan.

[0043] In the example shown in Figure 2, if the path length between the waypoint (final target position) associated with waypoint image 201-2 and the current position is less than the second threshold, the amount of fuel consumed by the time the ship reaches the final target position is not large. Therefore, the target ship speed determination unit 32 may determine the ship speed range in the target ship speed determination unit 32 so as to prioritize the ship arriving at the waypoint at the target arrival time over the fuel consumption of the main propulsion engine 4. In such a case (time priority mode), the target ship speed determination unit 32 determines the ship's target ship speed from within a ship speed range faster than a predetermined reference ship speed. This reference ship speed is predetermined, for example, based on the fuel consumption characteristics of the main propulsion engine 4.

[0044] In contrast, if fuel consumption is prioritized over the ship arriving at the waypoint at the target arrival time (fuel consumption priority mode), the target ship speed determination unit 32 may determine the ship's target ship speed from within a ship speed range slower than a predetermined reference ship speed.

[0045] As described above, the target speed determination unit 32 may determine the speed range such that, if the path length between the ship's final target position and its current position is less than the second threshold, the ship's arrival at the waypoint at the target arrival time takes precedence over the fuel consumption of the main propulsion engine 4. This makes it possible to adhere to the route plan and operate fuel-efficiently without the crew having to adjust the actual rotational speed of the main propulsion engine 4.

[0046] (Third embodiment) In the third embodiment, the main difference from the second embodiment is that the input device 5 inputs the indicated ship speed to the rotation speed determination device 3 instead of the electronic chart display information system 2. The third embodiment will be explained focusing on the differences from the second embodiment.

[0047] Figure 5 shows an example of the configuration of the rotational speed determination system 1 in the third embodiment. The rotational speed determination system 1 comprises a rotational speed determination device 3, a main propulsion engine 4, an input device 5, and a satellite positioning device 6. The rotational speed determination device 3 comprises a target ship speed calculation unit 31, a target ship speed determination unit 32, and a rotational speed determination unit 33.

[0048] Input device 5 is a device that accepts input operations, such as a keyboard. Input device 5 is operated, for example, by a crew member (navigator). The input operation is to input the position of each waypoint and the target time of arrival at each waypoint to the target ship speed calculation unit 31. The input operation may also be to input the target ship speed and the final target position to the target ship speed determination unit 32. Alternatively, the input operation may be to input the ship speed to the ground to the rotation speed determination unit 33.

[0049] The satellite positioning device 6 measures the ship's current position based on radio waves from satellites and the current time. The satellite positioning device 6 includes, for example, a satellite compass. The satellite positioning device 6 outputs the ship's current position and current time to the target ship speed calculation unit 31. The satellite positioning device 6 outputs the current position to the target ship speed determination unit 32.

[0050] As described above, the target ship speed calculation unit 31 may obtain the waypoint position and target arrival time from the input device 5. The target ship speed calculation unit 31 may obtain the current position and current time from the satellite positioning device 6. The target ship speed determination unit 32 may obtain the target ship speed from the input device 5. This makes it possible to adhere to the route plan and operate fuel-efficiently without the crew having to adjust the actual rotation speed of the main propulsion engine 4 according to the weather and sea conditions at the current position.

[0051] Among the embodiments disclosed herein, those composed of multiple objects may be integrated, and conversely, those composed of a single object may be divided into multiple objects. Whether or not they are integrated, the invention can be constructed in a way that achieves its objective.

[0052] In the embodiments disclosed herein, those in which multiple functions are provided in a distributed manner may have some or all of those multiple functions integrated into a single unit, and conversely, those in which multiple functions are integrated may have some or all of those functions provided in a distributed manner. Whether the functions are integrated or distributed, the configuration should be such that the objective of the invention can be achieved.

[0053] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention. [Explanation of Symbols]

[0054] 1…Rotation speed determination system, 2…Electronic chart display information system, 3…Rotation speed determination device, 4…Main propulsion engine, 5…Input device, 6…Satellite positioning device, 31…Target ship speed calculation unit, 32…Target ship speed determination unit, 33…Rotation speed determination unit, 101…Ship image, 201…Waypoint image

Claims

1. A target speed calculation unit calculates the target speed of the ship at a shorter interval than the update cycle of the instructed speed to the ship, based on the path length between the location of the waypoint and the ship's current position, and the difference between the target arrival time at the waypoint and the current time. A rotation speed determination unit that determines the instructed rotation speed to the ship's main propulsion engine based on the aforementioned target ship speed. A rotational speed determination device equipped with the following features.

2. The rotational speed determination device according to claim 1, wherein the target ship speed calculation unit selects a waypoint after the next waypoint if the path length between the position of the next waypoint and the current position is less than a first threshold, and calculates the target ship speed of the ship based on the path length between the position of the selected waypoint and the current position, and the difference between the target arrival time at the selected waypoint and the current time.

3. The rotation speed determination device according to claim 1, wherein the rotation speed determination unit temporarily suspends determining the indicated rotation speed until the ship arrives at the next waypoint if the path length between the position of the next waypoint and the current position is less than a first threshold.

4. The system further includes a target speed determination unit that determines the target ship speed from within a predetermined ship speed range, The rotation speed determination device according to claim 1, wherein the rotation speed determination unit determines the indicated rotation speed based on the determined target ship speed.

5. The rotational speed determination device according to claim 4, wherein the target ship speed determination unit determines the indicated ship speed, which has been overwritten by a ship speed within the ship speed range, or the indicated ship speed, which has been corrected to be within the ship speed range, as the target ship speed.

6. The aforementioned target ship speed determination unit acquires the indicated ship speed from the electronic chart display information system, The rotational speed determination device according to claim 4, wherein the target ship speed calculation unit obtains the position of the waypoint, the current position, the target arrival time, and the current time from the electronic chart display information system.

7. The target ship speed calculation unit obtains the position of the waypoint and the target arrival time from the input device, and obtains the current position and the current time from the satellite positioning device. The rotational speed determination device according to claim 4, wherein the target ship speed determination unit acquires the instructed ship speed from the input device.

8. The rotational speed determination device according to claim 4, wherein the target ship speed determination unit determines the ship speed range such that, when the path length between the ship's final target position and its current position is less than a second threshold, the ship's arrival at the waypoint at the target arrival time takes precedence over the fuel consumption of the main propulsion engine.

9. A step of calculating the target speed of the ship at a shorter interval than the update cycle of the instructed speed to the ship, based on the path length between the location of the waypoint and the current position of the ship, and the difference between the target time of arrival at the waypoint and the current time. A step of determining the number of rotations to be instructed to the main propulsion engine of the ship based on the target ship speed. A method for determining rotational speed, including the method described above.

10. On the computer, A procedure for calculating the target speed of a ship at a shorter interval than the update cycle for the instructed speed to the ship, based on the path length between the location of a waypoint and the ship's current position, and the difference between the target arrival time at the waypoint and the current time. A procedure for determining the instructed rotational speed to the main propulsion engine of the ship based on the aforementioned target ship speed, and A program to execute.

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