CN113212681A - Ship rolling period monitoring method - Google Patents
Ship rolling period monitoring method Download PDFInfo
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- CN113212681A CN113212681A CN202110467580.5A CN202110467580A CN113212681A CN 113212681 A CN113212681 A CN 113212681A CN 202110467580 A CN202110467580 A CN 202110467580A CN 113212681 A CN113212681 A CN 113212681A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B39/00—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude
- B63B39/14—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude for indicating inclination or duration of roll
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C15/00—Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
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- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Length Measuring Devices With Unspecified Measuring Means (AREA)
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Abstract
The invention relates to the technical field of ship detection, in particular to a ship rolling period monitoring method, which comprises the following steps: s1, collecting the ship rolling angle; s2, performing coarse difference removal processing on the rolling angle sequence; s3, if the length of the collected effective data sequence is more than 20, performing attenuation cosine curve fitting on the processed roll angle sequence; s4, continuously performing new fitting along with the increase of the collected data; s5, taking the effective data sequence to participate in fitting by adopting a sliding window method; and S6, calculating a measurement result according to the fitting result.
Description
Technical Field
The invention relates to the technical field of ship detection, in particular to a ship rolling period monitoring method.
Background
With the globalization of economy and the increasingly developed international trade, a large container ship is used as a main transport tool of a port, the navigation safety is particularly important, the floating state and the stability of the ship are important parameters for evaluating the safety of the ship, the stability of the ship is timely controlled, and serious accidents such as container ship overturning, channel blockage and the like can be effectively avoided.
As the stability of the ship mainly depends on the rationality of the stowage scheme, the method for controlling the stability of the ship at the present stage mainly comprises the following steps: the method comprises a loader loading method and a rolling period test method, wherein the loader loading method causes larger stability calculation errors due to box weight measurement errors, gravity height estimation, loading scheme deviation and the like; and the rolling period test method requires personnel excitation, so that the meter is clamped and the meter is counted, and the implementation difficulty is high.
Disclosure of Invention
In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a method for monitoring a ship rolling period, which measures a ship rolling angle by using a sensor installed on a dock or a ship, calculates the ship rolling period, and realizes rapid measurement of the ship rolling period.
The technical purpose of the invention is realized by the following technical scheme:
a ship rolling period monitoring method comprises the following steps:
s1, collecting the ship rolling angle, wherein the collection frequency cf is 10 Hz-50 Hz;
s2, coarse difference removing processing is carried out on the rolling angle sequence obtained in the step 1, the rolling angle data with overlarge deviation value are removed, and the data in the position is marked to be null, namely the position is marked to be null
S3, if the length of the collected effective data sequence is more than 20, performing attenuation cosine curve fitting on the processed roll angle sequence, wherein the fitting equation is as follows:
wherein phi is the roll inclination angle at any moment, N is the damping coefficient, omega is the roll angular velocity of the ship, A is the amplitude of the roll inclination angle,
the steady-state inclination angle of the rolling of the ship is t, and t is a time sequence t (i) of collected data, i is 0 … n;
since the vessel roll damping is linearly related in the case of small amplitude roll, the vessel roll damping is
d＝N*ω (2)
The resulting sets Φ ultimately represent the collected roll angle series (i), i being 0 … n.
S4, because the rolling period of the ship is generally 5-20 seconds, the set acquisition time t0 seconds and t0 can be adjusted and set according to the specific ship type, and when the time of the acquired data is less than t0 seconds, namely the acquired data volume is less than t0Cf, the number n of the data sequences subjected to fitting in the step 3 is continuously increased along with the acquisition time, in order to improve the operation efficiency, new fitting is performed once every 10 n data sequences are increased, and the fitting time j is 1 … k; the results for the jth fit are: a (j), N (j), ω (j),
s5, when the time length of data collection is longer than t0 seconds, namely the number of the collected data is larger than t0 cfc, effective data sequences are obtained by a sliding window method to participate in fitting, t0 cfc effective data sequences are entered into a queue, namely when the number of newly added effective data of the collected roll inclination angle is larger than 10, the earliest 10 effective data in the queue are moved out of the queue, each data in the sequence at the back is moved forward by 10 positions, the currently collected effective data are pressed into the queue to serve as the tail of the queue, then the new data sequences in the queue are fitted, and the queue is continuously updated by the method to be fitted subsequently;
s6, taking the fitting result of the previous step as the standard each time, calculating the real-time rolling period T of the ship to be 2 pi/omega, the rolling damping coefficient N of the ship, and the steady-state inclination angle of the ship
Further, in S4, t0 is adjusted according to the specific ship type so that 10S can be set for a small ship, 20S for a medium and large ship, and 40S for an ultra large passenger ship.
In conclusion, the invention has the following beneficial effects:
the method does not need a complex information system, and performs coarse difference removal processing by simply continuously acquiring the rolling angle sequence, improves the operation efficiency by a sliding window method, calculates the rolling period of the ship in real time by an attenuation cosine curve fitting method, provides a new method for quickly and efficiently measuring the stability of the ship, and is suitable for wide popularization.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, and are not to be considered limiting of the invention, in which:
FIG. 1 is a schematic view of the roll angle of a vessel according to the present invention;
FIG. 2 is a graph of roll angle attenuation of a vessel according to the present invention;
FIG. 3 is a schematic diagram of a data queue sliding window method for curve fitting according to the present invention.
Detailed Description
The foregoing and other technical matters, features and effects of the present invention will be apparent from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings of fig. 1 to 3. The structural contents mentioned in the following embodiments are all referred to the attached drawings of the specification.
Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.
Example 1: as shown in fig. 1 to 3, for the rolling and pitching of the ship, the amplitude and angle of the rolling and pitching are different at different positions of the ship, but the rolling and pitching periods are consistent, because in still water or irregular wave water areas, the rolling and pitching of the ship after being excited is damping motion, the rolling and pitching motion meets the damping cosine function, and for the small-amplitude rolling, the rolling and pitching damping of the ship is in a linear relation with the angular velocity.
Therefore, a ship rolling period monitoring method is provided, which comprises the following steps:
s1, collecting the ship rolling angle, wherein the collection frequency cf is 10 Hz-50 Hz;
s2, coarse difference removing processing is carried out on the rolling angle sequence obtained in the step 1, the rolling angle data with overlarge deviation value are removed, and the data in the position is marked to be null, namely the position is marked to be null
S3, if the length of the collected effective data sequence is more than 20, performing attenuation cosine curve fitting on the processed roll angle sequence, wherein the fitting equation is as follows:
wherein phi is the roll inclination angle at any moment, N is the damping coefficient, omega is the roll angular velocity of the ship, A is the amplitude of the roll inclination angle,
the steady-state inclination angle of the rolling of the ship is t, and t is a time sequence t (i) of collected data, i is 0 … n;
since the vessel roll damping is linearly related in the case of small amplitude roll, the vessel roll damping is
d＝N*ω (2)
The obtained multiple groups phi finally represent the collected roll inclination angle sequence
i＝0…n。
S4, since the rolling period of the ship is generally 5 to 20 seconds, the acquisition time t0 seconds is set, and t0 can be adjusted according to the specific ship type, for example, if the ship is a small ship, 10S can be set, and for a general large and medium ship, 20S can be set, 40S can be set for an ultra-large passenger ship, when the time for acquiring data is less than t0 seconds, that is, the amount of acquired data is less than t0 cf, the number n of data sequences to be fitted in step 3 increases with the acquisition time, in order to improve the operation efficiency, a new fitting is performed every time n increases by 10, and the number j of fitting times is 1 … k; the results for the jth fit are: a (j), N (j), ω (j),
s5, when the time length of data collection is longer than t0 seconds, namely the number of the collected data is larger than t0 cfc, effective data sequences are obtained by a sliding window method to participate in fitting, t0 cfc effective data sequences are entered into a queue, namely when the number of newly added effective data of the collected roll inclination angle is larger than 10, the earliest 10 effective data in the queue are moved out of the queue, each data in the sequence at the back is moved forward by 10 positions, the currently collected effective data are pressed into the queue to serve as the tail of the queue, then the new data sequences in the queue are fitted, and the queue is continuously updated by the method to be fitted subsequently;
s6, taking the fitting result of the previous step as the standard each time, calculating the real-time rolling period T of the ship to be 2 pi/omega, the rolling damping coefficient N of the ship, and the steady-state inclination angle of the ship
While the invention has been described in further detail with reference to specific embodiments thereof, it is not intended that the invention be limited to the specific embodiments thereof; for those skilled in the art to which the present invention pertains and related technologies, the extension, operation method and data replacement should fall within the protection scope of the present invention based on the technical solution of the present invention.
Claims (3)
1. A ship rolling period monitoring method is characterized by comprising the following steps:
s1, collecting the ship rolling angle, wherein the collection frequency cf is 10 Hz-50 Hz;
s2, coarse difference removing processing is carried out on the rolling angle sequence obtained in the step 1, the rolling angle data with overlarge deviation value are removed, and the data in the position is marked to be null, namely the position is marked to be null
S3, if the length of the collected effective data sequence is more than 20, performing attenuation cosine curve fitting on the processed roll angle sequence, wherein the fitting equation is as follows:
wherein phi is the roll inclination angle at any moment, N is the damping coefficient, omega is the roll angular velocity of the ship, A is the amplitude of the roll inclination angle,
the steady-state inclination angle of the rolling of the ship is t, and t is a time sequence t (i) of collected data, i is 0 … n;
since the vessel roll damping is linearly related in the case of small amplitude roll, the vessel roll damping is d ═ N × ω (2)
The obtained multiple groups phi finally represent the collected roll inclination angle sequence
S4, setting the acquisition time t0 seconds and t0 according to the specific ship type because the ship rolling period is generally 5-20 seconds, and when the acquisition time is less than t0 seconds, namely the acquired data amount is less than t0 cfs, the number n of the data sequences to be fitted in the step 3 is continuously increased along with the acquisition time, and in order to improve the operation efficiency, new fitting is performed once when n is increased by 10, and the fitting time j is 1 … k; the results for the jth fit are: a (j), N (j), ω (j),
s5, when the time length of data collection is longer than t0 seconds, namely the number of the collected data is larger than t0 cfc, effective data sequences are obtained by a sliding window method to participate in fitting, t0 cfc effective data sequences are entered into a queue, namely when the number of newly added effective data of the collected roll inclination angle is larger than 10, the earliest 10 effective data in the queue are moved out of the queue, each data in the sequence at the back is moved forward by 10 positions, the currently collected effective data are pressed into the queue to serve as the tail of the queue, then the new data sequences in the queue are fitted, and the queue is continuously updated by the method to be fitted subsequently;
s6, taking the fitting result of the previous step as the standard each time, calculating the real-time rolling period T of the ship to be 2 pi/omega, the rolling damping coefficient N of the ship, and the steady-state inclination angle of the ship
3. The method for monitoring the rolling period of the ship as claimed in claim 1, wherein in the step S4, the method for adjusting the setting of t0 according to the specific ship type is as follows: the set time is 10S for small ships, 20S for medium and large ships, and 40S for ultra-large passenger ships.
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| CN202110467580.5A CN113212681B (en) | 2021-04-28 | 2021-04-28 | Ship rolling period monitoring method |
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Citations (6)
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| US4918628A (en) * | 1985-12-18 | 1990-04-17 | University Of Southampton | Stability meter for floating objects |
| WO2004002815A1 (en) * | 2002-06-27 | 2004-01-08 | Kranskan Limited | Method and apparatus for monitoring the safety of a marine vessel |
| US20140316620A1 (en) * | 2011-09-16 | 2014-10-23 | Q-Tagg R&D Ab | Method and device for averting and damping rolling of a ship |
| CN105292397A (en) * | 2015-10-14 | 2016-02-03 | 武汉理工大学 | Method, system and device for monitoring and pre-warning inland ship stability in real time |
| CN107140110A (en) * | 2017-03-21 | 2017-09-08 | 山东省科学院海洋仪器仪表研究所 | A kind of ship large-amplitude roll kinematic nonlinearities damped coefficient recognition methods |
| CN111639390A (en) * | 2020-05-15 | 2020-09-08 | 上海理工大学 | Ship rolling motion parameter identification method based on vibration test |
-
2021
- 2021-04-28 CN CN202110467580.5A patent/CN113212681B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4918628A (en) * | 1985-12-18 | 1990-04-17 | University Of Southampton | Stability meter for floating objects |
| WO2004002815A1 (en) * | 2002-06-27 | 2004-01-08 | Kranskan Limited | Method and apparatus for monitoring the safety of a marine vessel |
| US20140316620A1 (en) * | 2011-09-16 | 2014-10-23 | Q-Tagg R&D Ab | Method and device for averting and damping rolling of a ship |
| CN105292397A (en) * | 2015-10-14 | 2016-02-03 | 武汉理工大学 | Method, system and device for monitoring and pre-warning inland ship stability in real time |
| CN107140110A (en) * | 2017-03-21 | 2017-09-08 | 山东省科学院海洋仪器仪表研究所 | A kind of ship large-amplitude roll kinematic nonlinearities damped coefficient recognition methods |
| CN111639390A (en) * | 2020-05-15 | 2020-09-08 | 上海理工大学 | Ship rolling motion parameter identification method based on vibration test |
Non-Patent Citations (1)
| Title |
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| 李海霞;: "波浪影响下船舶横摇运动的时间序列预测数学建模研究", 舰船科学技术 * |
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