JP6492387B1 - GM calculation system, method and program - Google Patents

Abstract

A system for accurately calculating GM in real time without using a separate sensor and using measurement data of an existing sensor without complicated data processing is provided. In a GM calculation system 1, a hull state quantity detecting means for detecting a hull state quantity in time series using a draft meter provided in the hull, and a hull detected in time series by the hull state quantity detecting means. Based on the state quantity, the rolling period detecting means for continuously detecting the rolling period of the hull, and the representative of the hull in the predetermined period based on the rolling period in the predetermined period detected by the rolling period detecting means Representative roll period identifying means for identifying the roll period, and GM calculating means for calculating a GM value of the hull based on the representative roll period identified by the representative roll period identifying means. [Selection] Figure 3

Description

  The present invention relates to a GM calculation system, method, and program.

  In the marine field (ship operation), for ships navigating on irregularly changing waves, from the viewpoint of safety measures, hull motion data that is data relating to hull motion such as hull acceleration and displacement, and hull It is an important matter to accurately grasp the hull state data, which is data relating to the state of the hull such as drafts and GMs.

  In particular, grasping the GM of the hull in real time and accurately is the most important issue from the viewpoint of protecting the hull from overturning. The GM of the hull is the metacenter M, which is the point where the buoyancy direction with the center of buoyancy acting as the working shop intersects the vertical line passing through the center of gravity in the cross section of the ship, and the center of gravity of the hull. It is defined as the distance from G, and is a value that is displaced momentarily by the inclination of the hull. In the unlikely event that the GM is estimated incorrectly, it is not only safe to navigate, but in the worst case, there is a risk of overturning.

  On the other hand, it is necessary to consider not only the waves from the side but the combined waves of waves coming from various directions that affect the GM. Therefore, in the past, in order to accurately grasp or predict the GM, it is necessary to grasp the direction in which the waves are incident on the hull and to input the incident angle manually. However, it is not realistic to input the angle at which the wave is incident by human hand under the situation where the hull is overturned by a large wave.

  Therefore, in recent years, GM is estimated using an approximate expression or a model. (Patent Document 1).

Republished Patent No. 2015-178410

  According to the invention described in Patent Document 1, GM is calculated using a second-order linear stochastic model or general state space model based on time-series data of roll angles measured by a GPS compass or a gyro sensor. ing. According to such a technique, a separate sensor such as a GPS compass or a gyro sensor is required, and it is difficult to detect an accurate roll angle. In addition, the estimation method uses a plurality of models, and the data processing becomes complicated, and the GM cannot be estimated with high accuracy. For this reason, the actual GM value may be mistaken, and in the worst case, safety may be hindered.

  The present invention has been made in view of the above-mentioned problems, and it is not necessary to install a separate sensor, and the measurement data of an existing sensor is used to accurately perform GM in real time without requiring complicated data processing. The purpose is to provide a system for computing.

  The present invention provides the following solutions.

  The invention according to the first aspect includes a hull state quantity detecting means for detecting a hull state quantity in time series using a draft meter provided in the hull, and a hull detected in time series by the hull state quantity detecting means. Based on the state quantity, the rolling period detecting means for continuously detecting the rolling period of the hull, and based on the rolling period in the predetermined period detected by the rolling period detecting means, GM calculation system comprising: representative roll period identifying means for identifying a representative roll period; and GM calculating means for calculating a GM value of the hull based on the representative roll period identified by the representative roll period identifying means. I will provide a.

  According to the first aspect of the invention, since the GM value can be calculated using the draft meter provided in the hull, there is no need to add a separate sensor and complicated data processing is not performed. Both can provide a system capable of calculating a highly accurate GM value in real time.

  The invention according to the second feature is the invention according to the first feature, wherein the draft meter is provided on a left and right side of the hull, and the right and left sides of the hull detected by the right and left side The rolling cycle of the hull is detected from the hull state quantity.

  According to the invention relating to the second feature, since the roll period of the hull is detected using a draft meter installed on the left and right side of the hull, it is not necessary to know the angle of incidence of waves on the hull, It is possible to provide a system capable of calculating an accurate GM value without inputting a wave incident angle.

  The invention according to the third feature is the invention according to the first or second feature, wherein a quartz-type draft meter is used as the draft meter.

  According to the invention relating to the third feature, since a quartz-type draft meter is used as a draft meter for detecting a hull state quantity, unlike other types of draft meters, digital measurement is possible. It is possible to provide a system capable of calculating a GM value with higher accuracy without causing a conversion error due to D conversion.

  The invention according to a fourth feature is the invention according to the third feature, wherein, in the quartz-type draft meter, the transmission frequency of the crystal resonator is detected in time series as a hull state quantity.

  According to the fourth aspect of the invention, since the transmission frequency of the crystal resonator in the crystal draft meter is adopted as the hull state quantity to be detected, the fluctuation of the transmission frequency is directly and continuously determined as the rolling period. Can be measured. Therefore, it is not necessary to bother to convert to a specific physical quantity, and it is possible to provide a system capable of constructing a highly accurate GM calculation system with a small amount of data processing.

  According to the present invention, there is provided a system for accurately calculating GM in real time without using a separate sensor and using measurement data of an existing sensor without requiring complicated data processing. it can.

FIG. 1 is a block diagram showing a hardware configuration and software functions of a GM calculation system 1 in the present embodiment. FIG. 2 is a diagram illustrating an arrangement example of the draft meter with respect to the hull. FIG. 3 is a flowchart showing the GM calculation method in the present embodiment. FIG. 4 is an example of the hull state quantity database 31.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. This is merely an example, and the technical scope of the present invention is not limited to this.

[Configuration of GM calculation system 1]
FIG. 1 is a block diagram for explaining a hardware configuration and software functions of a GM calculation system 1 in the present embodiment.

  The GM calculation system 1 includes a control unit 10 that controls data, a communication unit 20 that communicates with users and other devices, a storage unit 30 that stores data, and an input unit 40 that receives input of information from the user. The display unit 50 that outputs data and images controlled by the control unit 10 and the measurement unit 60 that measures data are provided.

  The controller 10 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like.

  The communication unit 20 includes a device for enabling communication with other devices, for example, a Wi-Fi (Wireless Fidelity) compatible device compliant with IEEE 802.11.

  The control unit 10 reads a predetermined program and cooperates with the communication unit 20 and / or the measurement unit 60 as necessary, so that the hull state quantity detection module 11, the roll period detection module 12, and the representative roll The period identification module 13 and the GM calculation module 14 are realized.

  The storage unit 30 is a device that stores data and files, and includes a data storage unit such as a hard disk, a semiconductor memory, a recording medium, and a memory card. The storage unit 30 stores a hull state quantity database 31 to be described later.

  The type of the input unit 40 is not particularly limited. Examples of the input unit 40 include a keyboard, a mouse, and a touch panel.

  The type of the display unit 50 is not particularly limited. Examples of the display unit 50 include a monitor and a touch panel.

  In the present embodiment, the measuring unit 60 includes draft meters D1 to D2 provided to measure a draft value defined as a vertical distance from the water surface to the bottom of the hull. As shown in FIG. 2, the draft meter includes a draft meter D1 installed near the center of the hull bow, draft meters D2 and D3 installed one by one on the left and right near the center of the hull, and the vicinity of the stern of the hull. It consists of four units of draft meter D4.

[Configuration of draft meters D1 to D4]
A quartz-type draft meter is used as draft meters D1-D4 which constitute GM calculation system 1 in this embodiment. Hereinafter, the operation principle of the quartz-type draft meter will be described.

  In the quartz-type draft meter, a crystal resonator is used as a detection element. Since the crystal oscillator has the property that the transmission frequency changes in proportion to the applied pressure, in the quartz-type draft meter, the frequency is directly applied to the detection element by measuring with a counter. The water pressure at the position where the detection element is installed is detected and the draft value is calculated.

  A draft meter using a quartz oscillator measures the frequency of crystal transmission directly with a counter, so digital measurement is possible. Like a semiconductor draft meter, the pressure is measured as an analog signal and A / D Unlike conventional draft meters that require conversion, highly accurate draft detection without conversion errors is possible.

  That is, if another type of draft meter such as a semiconductor type is used, the pressure at the position where the draft meter is installed is measured in an analog manner. When data processing such as Fourier analysis is performed on the pressure measured in time series, it is necessary to convert the measured pressure value from an analog signal to a digital signal (A / D conversion). At that time, an error associated with the conversion of the analog signal into the digital signal occurs, so that the measurement error of the semiconductor draft meter is about 10 times the measurement error of the crystal draft meter in the present embodiment. turn into.

  And in this embodiment, the oscillation frequency of a crystal oscillator can be measured as a digital signal with a counter by using a crystal-type draft meter. Therefore, there is no need to digitally convert the measured data, conversion errors associated with A / D conversion can be eliminated, and GM values can be calculated with high accuracy.

[Flowchart showing GM calculation method using GM calculation system 1]
FIG. 3 is a flowchart showing a GM calculation method using the GM calculation system 1. FIG. 4 is a diagram illustrating an example of the hull state quantity database 31. Processing executed by each hardware and software module described above will be described with reference to FIGS. In the present embodiment, the GM value of the hull is repeatedly calculated by repeatedly executing the control logic from step S10 to step S50.

[Step S10: Hull State Quantity Detection]
First, when the system is started, the control unit 10 of the GM calculation system 1 executes the hull state quantity detection module 11 in cooperation with the measurement unit 60, and detects the hull state quantity in time series (step S10). The detection of the hull state quantity in step S10 is performed over a predetermined period at predetermined time intervals by a draft meter installed in the hull. The predetermined time interval can be set as appropriate, such as a 1 second interval or a 1/10 second interval.

  In the present embodiment, the oscillation frequency of the crystal is detected as time series data by the draft meters D2 and D3 installed on the left and right sides.

[Step S20: Detection of the hull roll cycle]
Next, the control unit 10 of the GM calculation system 1 executes the roll period detection module 12 and continuously detects the roll period of the hull, which is defined as the time interval of the maximum roll of the left and right sides (step) S20).

  In the present embodiment, the rolling period of the hull is detected based on the time-series data of the transmission frequency detected by the draft meters D2 and D3 installed on the left and right anchors. Since the detected transmission frequency is a state quantity corresponding to the pressure applied to the crystal resonator, the temporal variation of the transmission frequency represents the temporal variation of the pressure. Since this fluctuation represents the hull of the hull, the period of the waveform representing the time-series data of the transmission frequency in the draft meters D2 and D3 corresponds to the roll of the hull. In this embodiment, the peak at which the transmission frequency takes the maximum value and the minimum value is detected from the waveform representing the time-series data of the transmission frequency, and the rolling period is detected from the time between the peaks.

  In this embodiment, the rolling frequency of the hull is detected using the transmission frequency of the crystal measured using a crystal draft meter. However, the present invention is not limited to this, and the rolling cycle is not limited to this. Any other hull state quantity may be used as long as it can be detected. For example, the rolling cycle may be detected from the temporal fluctuation of the draft value of the left and right side. Alternatively, the roll cycle may be detected from the time variation of the tilt or roll amount.

  Further, in the present embodiment, the peak is detected from the waveform representing the time series data of the hull state quantity, and the rolling period is detected from the time between the peaks. The period may be detected using an existing statistical model representing the time series of fluctuations.

[Step S30: Storage of the hull roll cycle]
When the roll period of the hull is detected in step S20, the detected roll period is stored in the hull state quantity database 31 (step S30). The roll period is detected continuously, and the detected roll period value is accumulated in the hull state quantity database 31 together with the detected time as shown in FIG.

[Step S40: Identification of representative roll cycle]
Subsequently, the control unit 10 executes the representative roll cycle identification module 13 in cooperation with the storage unit 30, extracts the roll cycle of a predetermined period stored in the hull state quantity database 31, and extracts the extracted roll Using the swing period, the representative period of the roll period in the predetermined period is identified (step S40).

  Here, the predetermined period refers to, for example, a period of the past 20 minutes from the current time, and the representative period of the predetermined period in that case refers to a representative value of the rolling period in the 20 minutes. As described above, in step S30, the rolling cycle is stored together with the time. Then, all the rolling periods detected during a time that is a predetermined time (20 minutes here) from the current time are extracted, and the extracted rolling period data is subjected to Fourier analysis. Identify a representative period.

  The identification of the representative period in step S40 is performed every predetermined time, for example, every 2 seconds.

[Step S50: Calculation of GM Value]
Subsequently, the control unit 10 executes the GM calculation module 14 and calculates the GM value using the expression (1) using the representative period of the hull roll period identified in step S40. The calculated GM value is displayed on the display unit 50 in real time.
GM = (0.8B / Tγ ′) ² Equation (1)

  Here, B in the formula (1) is the width (m) of the hull, and Tγ ′ is the representative period (second) of the roll period identified by Fourier analysis in step S40.

  The calculation of the GM value in step S50 is executed at predetermined time intervals, for example, every 2 seconds, and the latest value is displayed on the display unit 50 each time the calculation is executed. The sailor can continue safe navigation by confirming the GM value displayed on the display unit 50 one by one and executing various controls relating to the hull.

In calculating the GM value, when it is desired to calculate more strictly, the equation (2) using the ring radius obtained by the center-of-gravity inspection (tilt test) at the time of new construction can be used.
GM = (2.01K / T) ² Equation (2)

  Here, K in Equation (2) is the hull's ringing radius (m), and T is the natural period (seconds) of the hull that varies with the draft value.

  When the hull's kinematic radius K (m) is available, it is possible to calculate the value of GM using the formula (2). However, even when Equation (1) is used, the value of GM can be calculated with the same accuracy as when Equation (2) is adopted.

  In this way, by using the time series data of the hull state quantity detected by the draft meter provided in the hull, by calculating the GM value using the representative period of the roll period identified by Fourier analysis, GM values can be calculated accurately and in real time without requiring complicated data processing. In addition, since the draft meter for detecting the hull state quantity is already installed in the hull, it is not necessary to install new sensors for calculating the GM value, and a low-cost and high-accuracy GM calculation system is provided. It becomes possible to construct.

  In addition, a special measurement is used to detect the rolling period, which is the time interval of the maximum roll of the left and right side of the hull, using time series data of the hull state quantity detected by the draft meter provided on the left and right side of the hull. It is possible to construct a highly accurate GM calculation system at a low cost by using an already equipped device without requiring a device or a high-performance computing device.

  Further, since a quartz-type draft meter is used as a draft meter for detecting the hull state quantity, unlike the other types of draft meters, the hull state quantity can be measured as a digital signal. Therefore, A / D conversion at the time of data processing becomes unnecessary, and it is possible to construct a highly accurate GM calculation system with no conversion error.

  And since the oscillation frequency of the crystal oscillator in the quartz-type draft meter provided on the left and right of the hull is adopted as the hull state quantity to be detected, the fluctuation of the oscillation frequency is directly and continuously measured as the rolling period. can do. Therefore, it is not necessary to bother to convert to a specific physical quantity, and it is possible to construct a highly accurate GM calculation system with a small amount of data processing.

[Measurement of draft value of hull]
A method of measuring the draft value of the hull using the draft meters D1 to D4 constituting the GM calculation system 1 in the present embodiment will be described.

  In calculating the GM value, the transmission frequency detected by the draft meters D2 and D3 was used. However, in measuring the draft value, the transmission frequency was converted into pressure (water pressure), and a detection element was installed therefrom. The water depth of the position is calculated, and the draft value of the hull is derived using the water depth and the distance from the installation position of the detection element to the ship bottom.

  As shown in FIG. 2, since the draft meter D1 at the bow portion is installed at a position shifted from the bow line, the measured value measured by the draft meter D1 is converted into the bow line position to obtain the bow draft value.

  In addition, since the draft meters D2 and D3 at the left and right sides near the center of the hull are installed at positions shifted from the hull center line, the measurement values measured by the draft meters D2 and D3 are used as the hull center line. The left and right draft values at the center of the hull are converted to

  And since the draft meter D4 of a stern part is installed in the position shifted from the stern line, it is set as a stern draft value by converting the measured value measured by the draft meter D4 into the stern line position.

  For the draft value thus obtained, temperature correction using the water temperature measured by the thermometer attached to each of the draft meters D1 to D4, and hull inclination correction by an automatic calculation function (trim: front and rear inclination, A corrected draft value can be obtained by performing (heel: lateral inclination).

  The specific gravity of seawater at a port differs depending on the general sea area, brackish water area, and fresh water area, so correction of seawater specific gravity at a port is performed by manually entering a measured value. Standard seawater specific gravity will be used in operation.

  The draft value of the hull is measured as described above.

[Identification of the encounter cycle with waves at the bow of the hull]
A method for identifying the encounter cycle of the hull bow using the draft meter D1 or D4 constituting the GM calculation system 1 in the present embodiment will be described.

  First, the pitching cycle of the bow or stern is measured using the draft meter D1 or D4. That is, as in the case of calculating the GM value, the fluctuation of the hull can be detected from the fluctuation of the transmission frequency of the quartz oscillator provided in the draft meter. Can be detected.

  And, from the fluctuation of the transmission frequency in the draft meter D1 or D4 provided at the bow or stern, the time interval of the maximum pitch of the bow or stern is continuously detected, and the detected continuous pitch period Fourier analysis is performed on the data, and the representative period of the pitch period is identified.

[Calculation of hull longitudinal deflection]
A method for calculating the deflection in the front-rear direction of the hull using the draft meters D1 to D4 constituting the GM calculation system 1 in the present embodiment will be described.

  The hull's longitudinal deflection is defined as the difference between the bow draft and stern draft averages and the hull center draft, and the hull is either hogging (convex) or sagging (concave) in the longitudinal direction. It is a value that indicates whether or not there is. In order to calculate this value, a time average of the draft value in a predetermined period such as 150 seconds is taken for each measured value.

  Then, the deflection value is calculated by subtracting the arithmetic average of the hull center draft value from the arithmetic average of the bow draft value and the stern draft value. This value is an important index that determines the magnitude of the hull bending moment and the loaded cargo weight, which are closely related to the hull strength. By accurately grasping this value, a serious accident can be prevented.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment mentioned above. The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

DESCRIPTION OF SYMBOLS 1 GM calculation system 10 Control part 11 Hull state quantity detection module 12 Rolling period detection module 13 Representative rolling period identification module 14 GM calculation module 20 Communication part 30 Storage part 31 Hull state quantity database 40 Input part 50 Display part 60 Measurement part

Claims (5)

A GM calculation system for calculating a GM value of a hull,
A hull state quantity detecting means for detecting the hull state quantity in time series using a flood gauge provided on the hull;
Based on the hull state quantities detected in time series by the hull state quantity detecting means, the roll period detecting means for continuously detecting the roll period of the hull;
Representative roll period identifying means for identifying a representative roll period of the hull in the predetermined period based on the roll period in the predetermined period detected by the roll period detecting means;
GM calculating means for calculating a GM value of the hull based on the representative roll period identified by the representative roll period identifying means ,
The water gauge is provided on the left and right side of the hull,
The rolling cycle detection means detects a peak at which the hull state quantity takes a maximum value and a minimum value from a waveform representing time series data of the hull state quantity detected by the water gauge provided on the left and right side, A GM calculation system that detects the rolling period of a hull from the time between peaks .   The GM calculation system according to claim 1, wherein a quartz water meter is used as the water meter.   3. The GM calculation system according to claim 2, wherein in the quartz water meter, a transmission frequency of the crystal resonator is detected in time series as a hull state quantity. 4. In the GM calculation system that calculates the GM value of the hull,
Detecting the state quantity of the hull in time series using a water gauge provided on the hull;
Continuously detecting the rolling period of the hull based on the hull state quantity detected in the time series;
Identifying a representative roll period of the hull in the predetermined period based on the detected roll period in the predetermined period;
Calculating a GM value of the hull based on the identified representative roll period ,
The water gauge is provided on the left and right side of the hull,
The step of continuously detecting the rolling period includes a maximum value and a minimum value of the hull state quantity from a waveform representing time series data of the hull state quantity detected by the water gauge provided on the left and right sides. A program for detecting peaks and detecting the rolling period of the hull from the time between peaks . A water gauge on the hull,
A hull state quantity detecting means for detecting the hull state quantity in time series using the water gauge;
Based on the hull state quantities detected in time series by the hull state quantity detecting means, the roll period detecting means for continuously detecting the roll period of the hull;
Representative roll period identifying means for identifying a representative roll period of the hull in the predetermined period based on the roll period in the predetermined period detected by the roll period detecting means;
GM calculating means for calculating a GM value of the hull based on the representative roll period identified by the representative roll period identifying means ,
The water gauge is provided on the left and right side of the hull,
The rolling cycle detection means detects a peak at which the hull state quantity takes a maximum value and a minimum value from a waveform representing time series data of the hull state quantity detected by the water gauge provided on the left and right side, A flood gauge used in the GM calculation system that detects the rolling period of the hull from the time between peaks .

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