SYSTEM AND METHOD FOR MONITORING SAFETY STATUS OF SHIP USING ROLL MOTION DATA

Abstract

Proposed are a system and a method for monitoring a safety status of a ship using roll motion data. The system and the method may be configured as follows. Rolling period data, average list angle data, and significant rolling angle data may be received from a rolling period computation part, an average list angle computation part, and a significant rolling angle computation part. It may be determined whether the rolling period data is equal to or less than a maximum unique rolling period. On the basis of the maximum unique rolling period, a controller may determine whether a rolling period is in a normal, caution, or danger state.

Claims

1. A system for monitoring a safety status of a ship using roll motion data, the system comprising: a rolling period computation processor configured to compute rolling period data by performing fast Fourier transform (FFT) analysis on rolling angle data over time shown by an electronic inclinometer; an average list angle computation processor configured to compute average list angle data by performing FFT analysis on the rolling angle data; a significant rolling angle computation processor configured to compute significant rolling angle data by performing FFT analysis on the rolling angle data; a controller configured to: receive the computed rolling period data, the computed average list angle data, and the computed significant rolling angle data, perform comparative analysis on the rolling period data with a maximum unique rolling period and the maximum unique rolling period+40% of the maximum unique rolling period to determine a normal, caution, or danger state of a rolling period, perform comparative analysis on the average list angle data with 50% of a grade criterion and the grade criterion to determine a normal, caution, or danger state of an average list angle, perform comparative analysis on the significant rolling angle data with 50% of the grade criterion and the grade criterion to determine a normal, caution, or danger state of an average significant rolling angle, and output a display control signal corresponding to each of the determined states; and a display configured to receive the display control signal from the controller and display the display control signal.

2. The system of claim 1, wherein as the grade criterion, the lesser of a limit inclination angle of the ship and 10 [deg] is selected.

3. A method for monitoring a safety status of a ship by using a system for monitoring the safety status of the ship using roll motion data, the method comprising: receiving, by a controller, rolling period data, average list angle data, and significant rolling angle data from a rolling period computation processor, an average list angle computation processor, and a significant rolling angle computation processor; determining, by the controller, whether the rolling period data is equal to or less than a maximum unique rolling period; determining, by the controller, that a rolling period is in a normal state and displaying a rolling period normal state through a display in response to the rolling period data being equal to or less than the maximum unique rolling period; determining, by the controller, that the rolling period is in a caution state and displaying a rolling period caution state through the display in response to the rolling period data is greater than the maximum unique rolling period and is equal to or less than the maximum unique rolling period+40% of the maximum unique rolling period; and determining, by the controller, that the rolling period is in a danger state and displaying a rolling period danger state through the display when the rolling period data is greater than the maximum unique rolling period+40% of the maximum unique rolling period.

4. The method of claim 3, after the receiving, further comprising: determining, by the controller, whether the average list angle data is equal to or less than 50% of a grade criterion; determining, by the controller, that an average list angle is in a normal state and displaying a list angle normal state through the display in response to the average list angle data being equal to or less than 50% of the grade criterion; determining, by the controller, that the average list angle is in a caution state and displaying an average list angle caution state through the display in response to the average list angle data being greater than 50% of the grade criterion and being equal to or less than the grade criterion; and determining, by the controller, that the average list angle is in a danger state and displaying an average list angle danger state through the display in response to the average list angle data being greater than the grade criterion.

5. The method of claim 3, after the receiving, further comprising: determining, by the controller, whether the significant rolling angle data is equal to or less than 50% of a grade criterion; determining, by the controller, that a significant rolling angle is in a normal state and displaying a significant rolling angle normal state through the display when the significant rolling angle data is equal to or less than 50% of the grade criterion; determining, by the controller, that the significant rolling angle is in a caution state and displaying a significant rolling angle caution state through the display in response to the significant rolling angle data being greater than 50% of the grade criterion and being equal to or less than the grade criterion; and determining, by the controller, that the significant rolling angle is in a danger state and displaying a significant rolling angle danger state through the display in response to the significant rolling angle data being greater than the grade criterion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other objectives, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings.

[0016] FIG. 1 is a block diagram illustrating a system for monitoring a safety status of a ship using roll motion data, according to an embodiment of the present disclosure.

[0017] FIG. 2 is a flowchart illustrating a method for monitoring a safety status of a ship using roll motion data, according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0018] In describing embodiments of the present disclosure, if it is decided that a detailed description of the known art related to the present disclosure makes the subject matter of the present disclosure unclear, the detailed description will be omitted. Further, the terms described below are defined in consideration of the functions in the present disclosure, and may be changed depending on the intention of a user, an operator, or a usual practice. Therefore, the definition should be based on the contents throughout this specification. The terms used below are merely for describing the embodiments of the present disclosure, and should not be restrictively interpreted. Unless clearly used otherwise, a singular expression includes a plural meaning. In the description, the expression include or have is for indicating any features, numbers, steps, operations, elements, or a part or combination thereof, and should not be interpreted as excluding presence or possibility of one or more other features, numbers, steps, operations, elements, or a part or combination thereof other than the above.

[0019] In each system shown in the drawings, elements in some cases may have same or different reference numerals to suggest that the elements could be different or similar. However, elements may have different implementations and work with some or all of the systems shown or described in the specification. The various elements shown in the drawings may be the same or different. It is random which one is referred to as a first element and which one is referred to as a second element.

[0020] In the specification, when one element transmits, transfers, or provides data or a signal to another element, it means that the element transmits the data or signal directly to the other element or the element transmits the data or signal to the other element via at least one another element.

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0022] FIG. 1 is a block diagram illustrating a system for monitoring a safety status of a ship using roll motion data, according to an embodiment of the present disclosure.

[0023] The system for monitoring the safety status of a ship using roll motion data according to the embodiment of the present disclosure is provided in the ship and is executed by receiving measured data from an electronic inclinometer 100. A rolling period computation part (or a rolling period computation processor) 200, an average list angle computation part (or an average list angle computation processor) 210, a significant rolling angle computation part (or a significant rolling angle computation processor) 220, a controller 300, and a display 400 are in an on-board form.

[0024] The rolling period computation part 200 computes rolling period data by performing fast Fourier transform (FFT) analysis on rolling angle data over time shown by the electronic inclinometer 100. A rolling period refers to the time that it takes for a ship to tilt from its maximum inclination on one side to the opposite side and return to its original position. In other words, the rolling period refers to the time required to heel from the starboard rolling angle to the port rolling angle and back to the starboard rolling angle, and the unit is [sec].

[0025] The average list angle computation part 210 computes average list angle data by performing FFT analysis on rolling angle data over time shown by the electronic inclinometer 100. A list angle refers to the angle of a ship when the ship is tilted laterally and remains in a parallel state in still water. The list angle is an indicator that there is a possibility that a ship may tilt to one side when the ship is damaged and flooded. Small fishing boats, for example, may be observed to be at anchor or to sail while tilted rather than upright during anchoring or sailing due to a lopsided load when fishing gear is loaded onto the boats. This indicates that the list angle is not upright. In particular, since it is difficult to intuitively compute the list angle of a ship at sea, the average list angle is a main safety factor that can be used to determine whether the ship is upright through an average value of rolling angles for the port and the starboard by using the electronic inclinometer 100 in order to quantitatively observe the upright state of the ship for the safety of the ship. The average list angle is shown by computing an average value of port and starboard rolling angles for each FFT analysis and averaging the average values for the total number (n) of trials.

[0026] The significant rolling angle computation part 220 computes significant rolling angle data by performing FFT analysis on rolling angle data over time shown by the electronic inclinometer 100. A rolling angle refers to the maximum angle at which a ship is tilted due to the roll of the ship. A list angle refers to a static angle, while the rolling angle refers to a dynamic angle caused by the roll of a ship. The rolling angle is a factor that may occur independently depending on the sea and sailing conditions regardless of damage or flooding of the ship. The electronic inclinometer 100 expresses the port rolling angle as a negative number () and the starboard rolling angle as a positive number (+). An average value of top of rolling angles (for the port and the starboard each) of a ship is defined as a significant rolling angle. The significant rolling angle may be used as a main indicator to know a significant value of an inclination angle due to roll. In order to compute the significant rolling angle, the maximum rolling angle for the port and the starboard each is derived for each FFT analysis and a significant value is computed so that the significant rolling angle is computed when a unique rolling period is computed. Since it is a significant value, the average value of of the data is computed, and the computed significant rolling angles are averaged for the total number (n) of trials.

[0027] The controller 300 is a microcomputer that controls all elements. The controller 300 receives rolling period data, average list angle data, and significant rolling angle data computed by the rolling period computation part 200, the average list angle computation part 210, and significant rolling angle computation part 220, and performs comparative analysis to determine a normal, caution, or danger state of the rolling period, the average list angle, and the significant rolling angle, and outputs and displays a display control signal corresponding to each determined state to the display 400. The controller 300 performs comparative analysis on the input rolling period data with the maximum unique rolling period and the maximum unique rolling period+40% of the maximum unique rolling period to determine the normal, caution, or danger state of the rolling period. The controller 300 performs comparative analysis of average list angle data with 50% of a grade criterion and the grade criterion to determine the normal, caution, or danger state of the average list angle. The controller 300 performs comparative analysis of significant rolling angle data with 50% of the grade criterion and the grade criterion to determine the normal, caution, or danger state of an average significant rolling angle. The lesser of the limit inclination angle of the ship and 10 [deg] may be selected as the grade criterion.

[0028] The same grade criterion may be applied to the average list angle and the significant rolling angle for grade classification. In the meantime, in addition to applying 50% of the grade criterion in the caution grade, an experience point of a crew member based on long experience may be manually received and applied.

[0029] Based on [Table 1] and [Table 2] below, the characteristics of each element will be described as follows.

[0030] Referring to the rolling period, there is a clear distinction between caution and danger using the top of a unique rolling period range of each ship as a criterion and 40% of the value as a criterion. In particular, considering that ship H and ship I, which are ships for passengers and cars, have flat surfaces and are much less sensitive to changes in the marine environment than training ships or passenger ships, the fact that the rolling periods of the ships exceed 7 seconds directly indicates that the marine environment is very unstable. From the same perspective, for the average list angle and the significant rolling angle, even if the ships for passengers and cars have a slightly larger change in the inclination angles than other ships, this indicates that the ships for passengers and cars are in a very dangerous condition. That is, it is well demonstrated that ship G having an inclination angle of about 5 degrees is in a normal range while ship I having an inclination angle of 5 degrees is in a very dangerous condition. Most training ships and passenger ships ensure safety even when the extent of the limit inclination angle exceeds 10 degrees, so there is no problem in applying a criterion of 10 degrees to secure sufficient universality for the risk.

TABLE-US-00001 TABLE 1 Unique Limit rolling inclination period angle extent Types LBP Breadth range and designation of ships [m] [m] [sec] [deg] A Training ships 120.0 19.4 9.6-11.7 11.6-16.0/10 B 104.0 25.0 10.1-13.7 11.6-16.0/10 C Passenger ships 148.0 24.8 10.6-13.0 11.3-16.0/10 D 175.0 27.0 11.6-18.9 10.8-13.9/10 E 171.0 27.0 14.3-17.1 11.4-12.4/10 F 102.0 17.8 10.4-14.6 10.8-13.2/10 G 147.0 25.0 11.0-19.1 11.3-16.0/10 H Ships for passengers 47.0 12.0 4.6-5.1 5.9-8.9/5.9 I and cars 55.0 13.0 4.9-5.2 4.4-8.1/4.4

TABLE-US-00002 TABLE 2 Average list angle/significant Rolling rolling angle Classification Determination period [sec] [deg]. Ship A Normal 11.7 5.0 Caution 16.4 10.0 Danger >16.4 >10.0 Ship B Normal 13.7 5.0 Caution 19.2 10.0 Danger >19.2 >10.0 Ship C Normal 13.0 5.0 Caution 18.2 10.0 Danger >18.2 >10.0 Ship D Normal 18.9 5.0 Caution 26.5 10.0 Danger >26.5 >10.0 Ship E Normal 17.1 5.0 Caution 23.9 10.0 Danger >23.9 >10.0 Ship F Normal 14.6 5.0 Caution 20.4 10.0 Danger >20.4 >10.0 Ship G Normal 19.1 5.0 Caution 26.7 10.0 Danger >26.7 >10.0 Ship H Normal 5.1 3.0 Caution 7.1 5.9 Danger >7.1 >5.9 Ship I Normal 5.2 2.2 Caution 7.3 4.4 Danger >7.3 >4.4

[0031] The display 400 receives a display control signal from the controller 300 and displays the normal, caution, or danger state for the rolling period, the average list angle, and the significant rolling angle of the ship. As the display 400, an output device, such as a PDP, LCD, LED, or OLED display, may be used.

[0032] A method for monitoring a safety status of a ship by using the system for monitoring the safety status of the ship using roll motion data according to the embodiment of the present disclosure configured as described above will be described.

[0033] FIG. 2 is a flowchart illustrating a method for monitoring a safety status of a ship using roll motion data, according to an embodiment of the present disclosure. Herein, S denotes a step.

[0034] First, the controller 300 receives rolling period data, average list angle data, and significant rolling angle data from the rolling period computation part 200, the average list angle computation part 210, and the significant rolling angle computation part 220 in step S100.

[0035] Next, the controller 300 determines whether the rolling period data is equal to or less than the maximum unique rolling period in step S200.

[0036] When the rolling period data is equal to or less than the maximum unique rolling period in step S200 (Y), the controller 300 determines that the rolling period is in the normal state and displays a rolling period normal state through the display 400 in step S230.

[0037] When the rolling period data is greater than the maximum unique rolling period in step S200 (N), the controller 300 determines whether the rolling period data is equal to or less than the maximum unique rolling period+40% of the maximum unique rolling period in step S210.

[0038] When the rolling period data is equal to or less than the maximum unique rolling period+40% of the maximum unique rolling period in step S210 (Y), the controller 300 determines that the rolling period is in the caution state and displays a rolling period caution state through the display 400 in step S240.

[0039] When the rolling period data is greater than the maximum unique rolling period+40% of the maximum unique rolling period in step S210, the controller 300 determines that the rolling period is in the danger state and displays a rolling period danger state through the display 400 in step S220.

[0040] In the meantime, after step S100, the controller 300 determines whether the average list angle data is equal to or less than 50% of the grade criterion in step S300.

[0041] When the average list angle data is equal to or less than 50% of the grade criterion in step S300, the controller 300 determines that the average list angle is in the normal state and displays a list angle normal state through the display 400 in step S330.

[0042] When the average list angle data is greater than 50% of the grade criterion in step S300 (N), the controller 300 determines whether the average list angle data is equal to or less than the grade criterion in step S310.

[0043] When the average list angle data is equal to or less than the grade criterion in step S310 (Y), the controller 300 determines that the average list angle is in the caution state and displays an average list angle caution state through the display 400 in step S340.

[0044] In the meantime, when the average list angle data is greater than the grade criterion in step S310 (N), the controller 300 determines that the average list angle is in the danger state and displays an average list angle danger state through the display 400 in step S320.

[0045] In the meantime, after step S100, the controller 300 determines whether the significant rolling angle data is equal to or less than 50% of the grade criterion in step S400.

[0046] When the significant rolling angle data is equal to or less than 50% of the grade criterion in step S400 (Y), the controller 300 determines that the significant rolling angle is in the normal state and displays a significant rolling angle normal state through the display 400 in step S430.

[0047] When the significant rolling angle data is greater than 50% of the grade criterion in step S400 (N), the controller 300 determines whether the significant rolling angle data is equal to or less than the grade criterion in step S410.

[0048] When the significant rolling angle data is equal to or less than the grade criterion in step S410 (Y), the controller 300 determines that the significant rolling angle is in the caution state and displays a significant rolling angle caution state through the display 400 in step S440.

[0049] When the significant rolling angle data is greater than the grade criterion in step S410 (N), the controller 300 determines that the significant rolling angle is in the danger state and displays a significant rolling angle danger state through the display 400 in step S420.

[0050] According to the system and the method for monitoring a safety status of a ship using roll motion data according to the embodiments of the present disclosure, the rolling period data, the average list angle data, and the significant rolling angle data are received from the rolling period computation part, the average list angle computation part, and the significant rolling angle computation part, and it is determined whether the rolling period data is equal to or less than the maximum unique rolling period. When the rolling period data is equal to or less than the maximum unique rolling period, it is determined that the rolling period is in the normal state and the rolling period normal state is displayed through the display. When the rolling period data is greater than the maximum unique rolling period and is equal to or less than the maximum unique rolling period+40% of the maximum unique rolling period, the controller determines that the rolling period is in the caution state and displays the rolling period caution state through the display. When the rolling period data is greater than the maximum unique rolling period+40% of the maximum unique rolling period, it is determined that the rolling period is in the danger state and the rolling period danger state is displayed through the display. Accordingly, the criteria and configuration for generating an alarm signal that displays the safety status of the ship on the basis of the roll motion data of the ship obtained from the electronic inclinometer can be specifically provided.

[0051] The optimum exemplary embodiments have been disclosed and the specific terms are used in the drawings and the specification, but the exemplary embodiments and the terms are used just for the purpose of describing the exemplary embodiments of the present disclosure, but not used to limit meanings or restrict the scope of the present disclosure disclosed in the claims. Therefore, those skilled in the art will understand that various modifications of the exemplary embodiment and any other exemplary embodiments equivalent thereto are available. Accordingly, the true technical protection scope of the present disclosure should be determined by the technical idea of the appended claims.