CN-116484587-B - Method for evaluating ship ride the wave probability based on AIS data in irregular wave

CN116484587BCN 116484587 BCN116484587 BCN 116484587BCN-116484587-B

Abstract

The invention discloses a method for evaluating ship ride the wave probability based on AIS data in irregular waves, which comprises the steps of 1, establishing a probability density function of ship density based on the ship AIS data, 2, selecting a representative route and selecting a plurality of test points equidistantly, obtaining probability of occurrence of specific random sea conditions of a target sea area according to a wave scatter diagram of a sea area near the test points, 3, calculating ride the wave probability of the ship in the random waves, 4, calculating ride the wave probability of specific irregular waves of one test point of the representative route in the random waves, 5, calculating ride the wave probability of the ship under each random sea condition of the test points, and calculating ride the wave probability of the ship of other test points according to the same steps. The method solves the related problem of ride the wave motion of the ship in the irregular wave, can forecast the probability of ride the wave motion of the ship in the irregular wave, can directly obtain the ride the wave motion probability of the ship in the irregular wave according to the calculation result, has high solving precision and high efficiency, and is suitable for various ship types.

Inventors

WANG LIYUAN
CAO DONGXU
GU JIAYANG
Qu Jishun
REN CAILONG
LI RONG
CHEN ZHITONG

Assignees

江苏科技大学
南通中远海运船务工程有限公司
江苏佼燕船舶设备有限公司
江苏科技大学海洋装备研究院

Dates

Publication Date: 20260508
Application Date: 20230327

Claims (7)

1. The method for evaluating the probability of the ship ride the wave based on AIS data in the irregular wave is characterized by selecting ship AIS data of a target sea area in target time, establishing a probability density function of ship density, determining a representative course of the target sea area through the probability density function, and solving the total occurrence probability of the ship ride the wave motion on the representative course based on a ship ride the wave nonlinear dynamics probability analysis method in the irregular wave, and comprises the following steps: Selecting ship AIS data of a target sea area in target time, establishing a probability density function of ship density, and solving the probability density function of the ship density by a non-parameter nuclear density estimation method to obtain a ship density map; selecting a ship critical density threshold value according to a ship density map, defining a region with larger traffic flow, identifying and representing a representative route region, selecting at least two test points at a medium distance in the representative route region, and obtaining the probability of occurrence of irregular waves of a specific sense wave height and characteristic period combination of a target sea area according to a wave scatter diagram of a sea area near the test points, wherein the probability is P 1 ; Step 3, calculating ride the wave probability P 2 of the ship in the target sea area in the irregular wave based on a ship ride the wave nonlinear dynamics probability analysis method in the irregular wave; Calculating the probability P of a ship ride the wave of a specific irregular wave of a test point of a representative route in the irregular wave according to the probability P 1 of the irregular wave of the target sea area and the probability P 2 of the ship in the irregular wave, and calculating the ride the wave probability of the ship under each random sea condition of the test point according to the wave scattering diagram in the coverage area of the representative route to obtain a ride the wave probability diagram of the test point; And 5, repeating the steps 2-4 to calculate the ship ride the wave probabilities in different irregular waves of other test points, obtaining ride the wave probability maps of the test points, and solving the total occurrence probability of the ship ride the wave motion on the representative route.
2. The method of evaluating probability of ship ride the wave based on AIS data in an irregular wave according to claim 1, wherein step 1 specifically comprises the steps of: Step 1.1 assuming x 1 、x 2 …x n is a sample of a random variable x, the probability density function of the random variable x is The probability density function of the ship density is as follows: where x is a random variable, Representing the ship density, x i represents the ith ship density sample, h represents the bandwidth length, n is the sample number; Step 1.2, selecting a Gaussian kernel function as a kernel function in the non-parametric kernel density estimation method, wherein the Gaussian kernel function has the following formula: step 1.3, selecting h as bandwidth; step 1.4, obtaining a ship density map by adopting a probability density function of the ship density obtained by a non-parameter kernel density estimation method, wherein the probability density function is as follows:
3. the method of evaluating probability of ship ride the wave based on AIS data in an irregular wave according to claim 1, wherein in step 2, 5 test points are selected.
4. The method of evaluating probability of ship ride the wave based on AIS data in an irregular wave according to claim 1, wherein step 3 specifically comprises the steps of: step 3.1, establishing a differential equation of the heave motion of the ship in the irregular wave: Wherein ζ' G is the ordinate of the center of gravity of the ship under the geodetic coordinate system, m is the ship displacement, m x is the hull additional mass in the heave direction, u is the instantaneous speed in the heave direction, R (u) is the ship resistance in still water, T (u, n) is the propeller thrust in still water, X ω (ξ G , T) is the wave force in the heave direction, and T is the time; Determining various coefficients in a differential equation of the heave motion, namely the mass m of the ship, the additional mass m x of the ship in the heave direction, the longitudinal resistance R (u) of the ship, the thrust T (u, n) of the propeller in the heave direction and the wave force X ω (ξ G , T applied to the ship in the heave direction; the hull longitudinal resistance R (u) is fitted using a cubic polynomial as follows: R(u)=r 1 u+r 2 u 2 +r 3 u 3 (5) wherein r 1 ,r 2 ,r 3 is obtained by calculation and fitting of ship body resistance test data or fluid mechanics numerical simulation software; the pitch direction propeller thrust T (u, n) is approximated by a polynomial: T(u,n)=(1-t p )ρn 2 D p 4 K T (6) Wherein n represents the rotational speed of the propeller, t p represents the thrust derate, ρ represents the sea water density, D p represents the propeller diameter, and K T represents the thrust coefficient of the propeller, calculated as: K T ＝k 0 +k 1 J P +k 2 J P 2 (7) Wherein J P represents the advance coefficient, K 0 ,k 1 ,k 2 can be obtained by fitting open water test data of the propeller; Step 3.3, under random sea conditions, solving wave force through linear superposition: Wherein ki is the wave number of the ith regular wave, ω i is the frequency of the ith regular wave, φ i is a random phase angle, γ i is a phase shift, a i is the ith regular wave amplitude, RAO (k i ) is the amplitude of the heave wave force generated by the ith regular wave unit amplitude, and N is a positive integer; And 3.4, calculating ride the wave probability P 2 of the ship in the irregular wave by an analytic method or a numerical method.
5. The method for evaluating the probability of a ship ride the wave based on AIS data in an irregular wave according to claim 4, wherein the resolving method in step 3.4 is specifically to solve the probability of a ship ride the wave in an irregular wave by using a Melnikov method, and the specific steps are as follows: Substituting formula (8) into formula (4) and performing dimensionless treatment to let y=kζ G , Considering the change of wave force due to irregular waves on the basis of regular waves, there are: the equation is rewritten as follows, with the undamped Hilmiton system on the left: Wherein: r,q,p 1 ,p 2 ,p 3 ∈R; η is a time-dependent random process, related to the irregular wave, with a spectral density function S η , and for the calculation of the analytical method, the irregular wave force is taken as a random wave force superimposed on the regular wave, η is expressed as follows: wherein omega n is the peak frequency of the wave spectrum, and c 1 (t) is the random phase angle; The Melnikov method is a function that characterizes the distance between a stable manifold and an unstable manifold as follows: the motion ride the wave of the ship in the irregular wave occurs ride the wave, the necessary condition is M (τ 0 ) <0, the excitation generated by the irregular wave is approximately Gaussian random process, melnikov process M (τ 0 ) obtained as linear change is Gaussian process, and the expressions of the mean mu M and the variance sigma z 2 are as follows: wherein H (ω) is a frequency response function calculated as: the probability density function of the normal distribution is: integrating the equation (16) to obtain a probability distribution function of the normal distribution: according to a probability distribution function of normal distribution, the probability of ride the wave occurring in an irregular wave is as follows:
6. The method for estimating the probability of the ship ride the wave based on the AIS data in the irregular wave according to claim 4, wherein the numerical method in step 3.4 is specifically: Substituting the formula (8) into the formula (4), and solving by adopting a Dragon-Gregory tower method to obtain a ship speed time history curve, wherein time is an abscissa, relative displacement and relative speed of the ship are an ordinate, and the instantaneous wave speed of random waves is shown in the following formula: Wherein ω (ζ s , t) is a random wave frequency, and k (ζ s , t) is a random wave number; Drawing an instantaneous wave velocity diagram of random waves according to a formula (19), wherein an upper cross critical value selects an intersection point of the instantaneous wave velocity and the ship velocity, a lower cross critical value selects an intersection point of the instantaneous wave velocity and the ship nominal velocity, a time node of the ship velocity exceeding the instantaneous wave velocity is defined as ride the wave starting time, a time node of the ship velocity lower than the nominal velocity is defined as ride the wave ending time, and the probability of the ship under a certain random working condition is the ratio of the sum t 0 of the intermittent ride the wave time to the numerical simulation duration t 1 ; For the same sea state, calculating the heave motion response under a plurality of random seed numbers, and carrying out statistical analysis on all results to reduce errors and obtain ride the wave probability P 2 ＝t 0 /t 1 of the ship in random waves.
7. The method of evaluating probability of ship ride the wave based on AIS data in irregular waves according to claim 1, wherein in step 4, the probability P of ship ride the wave of specific irregular wave in test point area of representative course in irregular wave is calculated according to probability P 1 of occurrence of irregular wave in target sea area and probability P 2 of ride the wave of ship in random wave, wherein: P=P 1 P 2 (20) And calculating ride the wave probability of the ship under each random sea condition of the test point according to the wave scattering diagram in the coverage area of the representative route, and obtaining a ride the wave probability diagram of the test point.

Description

Method for evaluating ship ride the wave probability based on AIS data in irregular wave Technical Field The invention belongs to the field of ship nonlinear motion analysis, and particularly relates to a method for evaluating ship ride the wave probability based on AIS data in irregular waves. Background Vessel ride the wave/whip motion is one of the failure modes in the second generation of complete stability of the vessel. The nonlinear dynamics of the vessel during ride the wave/whip motions are most pronounced in the mode of vessel destabilization. Mechanically analyzed, ride the wave states are equilibrium states where longitudinal wave forces, thrust forces and drag forces reach dynamic equilibrium when the ship speed is equal to the wave speed. The wavelength at which ride the wave movements of the vessel are typically made is about 1 to 3 times the vessel length, the wave is sufficiently steep and the speed of the vessel is comparable to the wave speed, which is about 75% of the wave speed. Unlike ride the wave motions under regular waves, ride the wave motions of the vessel in irregular waves are manifested as abnormally high motions of the vessel above nominal navigational speeds that occur over a period of time. Internationally, grim first confirms the existence of the abnormal motion phenomenon, performs statistical analysis on the duration of the abnormal motion phenomenon, then Spyrou and the like establish a differential equation of the single-degree-of-freedom heave motion of the ship in the irregular wave, solve the instantaneous speed of the ship, simultaneously solve the instantaneous wave speed in the wave in the time dimension and the space dimension respectively, take the lower value of the instantaneous wave speed and the nominal navigational speed as the critical speed for judging ride the wave occurrence, and define the acceleration ride the wave phenomenon (high run) in the irregular wave. At present, the research work on speed increase ride the wave in China is less, at present, the ride the wave motion research of ships in irregular waves is mainly focused on the optimization of a ride the wave calculation model, the definition of ride the wave motion limits, the theoretical research of correlation analysis of the probability of the occurrence of the transverse swing motion after ride the wave and the correlation, and the like, and the ship ride the wave analysis is not performed by combining the actual sea condition and the route probability, so that the related practical research such as ship route optimization and the like is performed. Disclosure of Invention The invention aims to provide a method for evaluating ship ride the wave probability based on AIS data in irregular waves, a ship density calculation model is established based on AIS data and a standard ship, a probability density function of ship density is evaluated by adopting a non-parameter kernel density method, a ship density map obtained through the probability density function is used for finding a certain sea area representative route, the occurrence probability of ship ride the wave motion on the representative route is researched, and in order to solve the limitation of ship nonlinear ride the wave motion in the irregular waves in a numerical method, the provided nonlinear dynamics probability analysis method for ship ride the wave in the irregular waves is used for analyzing the probability of ship ride the wave occurrence in the irregular waves by adopting a nonlinear dynamics analysis method for ship ride the wave motion, so that an analysis method and a safe navigation basis are provided for safe navigation of the ship. According to the method for evaluating the ship ride the wave probability based on AIS data in the irregular wave, provided by the invention, ship AIS data of a target sea area in target time is selected, a probability density function of ship density is established, a representative route of the target sea area is determined through the probability density function, and the ship ride the wave probability in the representative route irregular wave is determined based on a ship ride the wave nonlinear dynamics probability analysis method in the irregular wave, and the method comprises the following steps: Selecting ship AIS data of a target sea area in target time, establishing a probability density function of ship density, and solving the probability density function of the ship density by a non-parameter nuclear density estimation method to obtain a ship density map; selecting a ship critical density threshold value according to a ship density map, defining a region with larger traffic flow, identifying and representing a representative route region, selecting at least two test points at a medium distance in the representative route region, and obtaining the probability of occurrence of irregular waves of a specific sense wave height and characteristic period combination of a target se