Ship navigation performance optimization method and system considering uncertainty variables

Abstract

The invention provides a ship navigation performance optimization method and system considering uncertain variables, and the method comprises the steps: calculating ship oil consumption and ship energy efficiency operation indexes based on obtained ship operation parameters and port parameters, calculating an actual navigation speed value interval through employing a 3sigma criterion, taking the actual navigation speed value interval as a constraint condition, and carrying out the optimization of the ship navigation performance. Establishing a target function based on a preset weight coefficient, the ship oil consumption and the ship energy efficiency operation index; the method comprises the following steps: setting navigation intervals and weather intervals based on a time dimension, further calculating a weather array corresponding to each navigation interval by adopting a specific calculation method, and then setting an initial actual navigation speed of a certain navigation interval in an actual navigation speed value interval; and taking the initial actual navigational speed and the weather array corresponding to the navigation interval as the initial solution of the simulated annealing algorithm, and finally calculating the optimal navigational speed of each navigation interval by adopting the simulated annealing algorithm, thereby realizing the optimization of the ship navigation performance and effectively improving the ship navigation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of ship performance optimization, and in particular to a method and system for optimizing ship navigation performance taking into account uncertain variables. Background Art

[0002] In the overall design of a ship, its optimization design is the most critical part. At present, most of the research on the overall structural design of ships at home and abroad is based on a simple external environment, and regards important parameters such as the speed of the ship as fixed and known. However, in the actual navigation process of the ship, many factors are uncertain. If they are still analyzed as a fixed value, it is bound to cause a large error. Therefore, ignoring the influence of various uncertain factors will bring huge potential risks to the navigation of the ship.

[0003] In recent years, many scholars at home and abroad have conducted a lot of research on the uncertainty design of ships. However, the main problem in the uncertainty optimization design of ships is the establishment of uncertainty models, and research in this area is still in its infancy. At present, most of the ship optimization designs at home and abroad are designed under ideal conditions by taking variables as determined parameters. Therefore, almost all ship optimization design models are completed under the background of deterministic optimization theory. This type of optimization model does not consider the impact of uncertainty factors in actual navigation on ship performance, and takes uncertainty factors as determined quantities in optimization calculations. However, in the actual navigation process of ships, it is inevitable to encounter very bad sea conditions, and at the same time, it will induce many uncertain factors, such as wind and waves. These uncertain factors will become the reason why the ship design cannot meet the expected target performance requirements or the ship is out of control. Therefore, in order to ensure that the results we obtain through optimization design can adapt to the fluctuations of relevant uncertainty data, we need to fully consider the impact of various uncertain factors in the early stage of the overall design of the ship.

[0004] So far, there are still few methods for ship uncertainty optimization design. First, there is no simple and time-saving method to quantify and analyze the uncertainty in random uncertainty; second, there is a lack of in-depth research on factors related to uncertainty, and there is no necessary classification of the characteristics of uncertainty factors. Due to the lack of methods, data and information related to uncertainty optimization, the modeling and continuous optimization of uncertainty are limited. Summary of the invention

[0005] In order to solve the problems of lack of in-depth research on uncertainty-related factors and limitations of continuous optimization in the current ship uncertainty optimization process, the present invention provides a ship navigation performance optimization method considering uncertainty variables, which takes into account the speed uncertainty caused by the operation scenario, minimizes the fuel consumption of the ship and the ship energy efficiency operation index, and establishes an objective function with the speed value range as a constraint, while considering the weather conditions during the actual navigation of the ship, and designs a customized simulated annealing algorithm to obtain the optimal solution of the objective function, which can effectively improve the navigation performance of the ship. The present invention also relates to a ship navigation performance optimization system considering uncertainty variables.

[0006] The technical solution of the present invention is as follows:

[0007] A method for optimizing ship navigation performance considering uncertain variables, characterized in that it comprises the following steps:

[0008] Parameter acquisition step: acquiring ship operation parameters and port parameters, wherein the ship operation parameters include actual speed, total mileage, ship still water resistance, wave resistance, wind resistance, hull efficiency, propeller open water efficiency, relative rotation efficiency and shafting efficiency, and calculating the total resistance of the ship according to the ship still water resistance, wave resistance and wind resistance; the port parameters include initial departure time and final arrival time;

[0009] Calculation steps for ship fuel consumption and energy efficiency operation index: Calculate the ship fuel consumption based on the total resistance of the ship, total mileage, hull efficiency, propeller open water efficiency, relative rotation efficiency and shafting efficiency; then calculate the ship energy efficiency operation index based on the ship fuel consumption, total mileage and total cargo load;

[0010] Speed ​​range and objective function establishment steps: Based on the preset expected speed and using the 3sigma criterion, the maximum actual speed and the minimum actual speed are calculated respectively, and the actual speed range is constructed according to the actual speed, the maximum actual speed and the minimum actual speed; then, the actual speed range is used as a constraint condition, and the objective function is established based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index;

[0011] The correspondence and calculation steps of the total navigation interval and the total weather array are as follows: the navigation interval and the weather interval are set based on the time dimension, the total weather array is calculated according to the initial departure time, the final arrival time and the set weather interval, and the total number of navigation intervals is calculated according to the initial departure time, the final arrival time and the set navigation interval; and when the navigation interval and the weather interval are different in size, a navigation interval matrix is ​​constructed based on the initial departure time, the navigation interval and the total number of navigation intervals, and the initial departure time and the weather interval are combined with at least one of the navigation interval, the total weather array and the total number of navigation intervals to construct a weather interval matrix, and the weather array corresponding to each navigation interval is calculated according to the navigation interval matrix and the weather interval matrix;

[0012] Parameter initialization step: set the initial actual speed of a navigation interval within the actual speed value range, and use the initial actual speed and the weather array corresponding to the navigation interval as the initial solution of the simulated annealing algorithm, and calculate the initial objective function value of the navigation interval based on the initial solution;

[0013] Simulated annealing calculation steps: According to the initial solution, the candidate solution of the objective function is calculated through the simulated annealing algorithm, and it is determined whether the candidate solution is within the actual speed value range. If so, the current objective function value is calculated according to the candidate solution, and the current objective function value is compared with the initial objective function value. If the current objective function value is less than the initial objective function value, the candidate solution is used to replace the initial solution, and the candidate solution is used as the new initial solution; if the current objective function value is greater than or equal to the initial objective function value, the initial solution remains unchanged and is used as the new initial solution for the next round of iteration;

[0014] Optimal solution selection and ship navigation performance optimization steps: Repeat the simulated annealing calculation steps until the preset number of iterations is reached. The new initial solution when the preset number of iterations is reached is used as the optimal solution of the objective function, and the actual speed corresponding to the optimal solution is used as the optimal speed of the navigation interval, and then the optimal speed of each navigation interval is obtained, and the ship's navigation performance is optimized according to the optimal speed of each navigation interval.

[0015] Preferably, in the step of corresponding and calculating the total navigation interval and the total weather array, combining the initial departure time and the weather interval with at least one of the navigation interval, the total weather array and the total number of navigation intervals to construct the weather interval matrix specifically includes:

[0016] If the navigation interval is equal to the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval and total weather array; if the navigation interval is greater than the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval, navigation interval and total number of navigation intervals; if the navigation interval is less than the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval, navigation interval and total weather array.

[0017] Preferably, the ship operation parameters also include a propeller wake fraction, a thrust deduction fraction, and a propeller thrust coefficient and torque coefficient to be corrected.

[0018] Preferably, the thrust coefficient and the torque coefficient are corrected respectively using the Reynolds number and the roughness to obtain thrust coefficient correction value and torque coefficient correction value respectively; and the actual thrust coefficient and the actual torque coefficient of the propeller are calculated based on the thrust coefficient correction value, the torque coefficient correction value, the propeller thrust coefficient and the torque coefficient to be corrected, and the propeller open water efficiency is calculated based on the actual thrust coefficient and the actual torque coefficient.

[0019] Preferably, the propeller wake fraction is calculated using the Taylor method, and the thrust deduction fraction is calculated using the Heckscher method, and the hull efficiency is calculated based on the propeller wake fraction and the thrust deduction fraction.

[0020] A ship navigation performance optimization system considering uncertain variables is characterized by comprising a parameter acquisition module, a ship fuel consumption and energy efficiency operation index calculation module, a speed value interval and objective function establishment module, a total navigation interval and total weather array correspondence and calculation module, a parameter initialization module, a simulated annealing calculation module, and an optimal solution selection and ship navigation performance optimization module, which are connected in sequence.

[0021] The parameter acquisition module acquires ship operation parameters and port parameters. The ship operation parameters include actual speed, total mileage, ship still water resistance, wave resistance, wind resistance, hull efficiency, propeller open water efficiency, relative rotation efficiency and shafting efficiency. The total resistance of the ship is calculated based on the ship's still water resistance, wave resistance and wind resistance. The port parameters include initial departure time and final arrival time.

[0022] The ship fuel consumption and energy efficiency operation index calculation module calculates the ship fuel consumption according to the total resistance of the ship, the total mileage, the hull efficiency, the propeller open water efficiency, the relative rotation efficiency and the shafting efficiency; and then calculates the ship energy efficiency operation index according to the ship fuel consumption, the total mileage and the total cargo load;

[0023] The speed value interval and objective function establishment module calculates the actual speed maximum value and the actual speed minimum value based on the preset expected speed and the 3sigma criterion, and constructs the actual speed value interval according to the actual speed, the actual speed maximum value and the actual speed minimum value; and then uses the actual speed value interval as a constraint condition to establish the objective function based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index;

[0024] The total navigation interval and total weather array correspondence and calculation module sets the navigation interval and weather interval based on the time dimension, calculates the total weather array according to the initial departure time, the final arrival time and the set weather interval, and calculates the total number of navigation intervals according to the initial departure time, the final arrival time and the set navigation interval; and respectively constructs a navigation interval matrix based on the initial departure time, the navigation interval and the total number of navigation intervals when the navigation interval and the weather interval are different in size, and combines the initial departure time and the weather interval with at least one of the navigation interval, the total weather array and the total number of navigation intervals to construct a weather interval matrix, and calculates the weather array corresponding to each navigation interval according to the navigation interval matrix and the weather interval matrix;

[0025] The parameter initialization module sets an initial actual speed of a navigation interval within the actual speed value range, and uses the initial actual speed and the weather array corresponding to the navigation interval as the initial solution of the simulated annealing algorithm, and calculates the initial objective function value of the navigation interval according to the initial solution;

[0026] The simulated annealing calculation module calculates a candidate solution of the objective function according to the initial solution and through the simulated annealing algorithm, and determines whether the candidate solution is within the actual speed value range. If so, the current objective function value is calculated according to the candidate solution, and the current objective function value is compared with the initial objective function value. If the current objective function value is less than the initial objective function value, the initial solution is replaced by the candidate solution, and the candidate solution is used as the new initial solution; if the current objective function value is greater than or equal to the initial objective function value, the initial solution remains unchanged and is used as the new initial solution for the next round of iteration;

[0027] The optimal solution selection and ship navigation performance optimization module repeats the work of the simulated annealing calculation module until a preset number of iterations is reached, and the new initial solution when the preset number of iterations is reached is used as the optimal solution of the objective function, and the actual speed corresponding to the optimal solution is used as the optimal speed of the navigation interval, thereby obtaining the optimal speed of each navigation interval, and optimizing the ship's navigation performance according to the optimal speed of each navigation interval.

[0028] Preferably, in the total navigation interval and total weather array correspondence and calculation module, combining the initial departure time and weather interval with at least one of the navigation interval, the total weather array and the total navigation interval number to construct the weather interval matrix specifically includes:

[0029] If the navigation interval is equal to the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval and total weather array; if the navigation interval is greater than the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval, navigation interval and total number of navigation intervals; if the navigation interval is less than the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval, navigation interval and total weather array.

[0030] Preferably, the ship operation parameters also include a propeller wake fraction, a thrust deduction fraction, and a propeller thrust coefficient and torque coefficient to be corrected.

[0031] Preferably, the thrust coefficient and the torque coefficient are corrected respectively using the Reynolds number and the roughness to obtain thrust coefficient correction value and torque coefficient correction value respectively; and the actual thrust coefficient and the actual torque coefficient of the propeller are calculated based on the thrust coefficient correction value, the torque coefficient correction value, the propeller thrust coefficient and the torque coefficient to be corrected, and the propeller open water efficiency is calculated based on the actual thrust coefficient and the actual torque coefficient.

[0032] Preferably, the propeller wake fraction is calculated using the Taylor method, and the thrust deduction fraction is calculated using the Heckscher method, and the hull efficiency is calculated based on the propeller wake fraction and the thrust deduction fraction.

[0033] The beneficial effects of the present invention are:

[0034] The present invention provides a method for optimizing ship navigation performance considering uncertain variables. The method comprises the following steps: firstly calculating the ship fuel consumption and the ship energy efficiency operation index based on the acquired ship operation parameters and port parameters, respectively calculating the maximum speed and the minimum speed based on the preset expected speed and adopting the 3sigma criterion, and constructing a speed value interval according to the actual speed, the maximum speed and the minimum speed; then taking the speed value interval as a constraint condition, establishing an objective function based on the preset weight coefficient, the ship fuel consumption and the ship energy efficiency operation index; then setting the navigation interval and the weather interval based on the time dimension, and calculating the weather array corresponding to each navigation interval; then setting the initial actual speed of a certain navigation interval within the speed value interval, and taking the initial actual speed and the weather array corresponding to the navigation interval as the initial solution of the simulated annealing algorithm, and calculating the initial objective function value of the navigation interval according to the initial solution; then calculating the optimal solution through the simulated annealing algorithm, and taking the actual speed corresponding to the optimal solution as the optimal speed of the navigation interval, thereby obtaining the optimal speed of each navigation interval, and optimizing the ship navigation performance according to the optimal speed of each navigation interval.

[0035] The present invention takes into account various factors such as ship operation parameters and port parameters, and quantifies the uncertainty of ship speed with the help of a normal model based on the 3sigma criterion. By optimizing the performance of the ship under the uncertainty variable factor of the ship speed, the fuel consumption of the ship and the ship energy efficiency operation index EEOI are reduced, so that the fleet can achieve efficient operation and improve the overall transportation efficiency, which will bring many benefits, including reducing operating costs, increasing the dry bulk cargo transshipment volume, reducing empty travel and waiting time, and reducing energy consumption and environmental pollution. At the same time, it can also help the fleet achieve efficient operation, maximize benefits and improve transportation efficiency.

[0036] The present invention also relates to a ship navigation performance optimization system considering uncertainty variables. The system corresponds to the above-mentioned ship navigation performance optimization method considering uncertainty variables, and can be understood as a system that implements the above-mentioned ship navigation performance optimization method considering uncertainty variables, including a parameter acquisition module, a ship fuel consumption and energy efficiency operation index calculation module, a speed value range and objective function establishment module, a total navigation range and total weather array correspondence and calculation module, a parameter initialization module, a simulated annealing calculation module, and an optimal solution selection and ship navigation performance optimization module, which are connected in sequence. The modules work together to consider the uncertainty variable of speed caused by the operation scenario, with the goal of minimizing the ship's fuel consumption and ship energy efficiency operation index, and establish an objective function with the speed value range as a constraint, while considering the weather conditions during the actual navigation of the ship, and designing a customized simulated annealing algorithm to obtain the optimal solution of the objective function, which can effectively improve the navigation performance of the ship. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a flow chart of the method for optimizing the navigation performance of a ship taking into account uncertain variables of the present invention.

[0038] Figure 2 It is a schematic diagram of the normal distribution solution of the 3sigma criterion of the present invention.

[0039] Figure 3 It is a flow chart of the simulated annealing algorithm of the present invention. DETAILED DESCRIPTION

[0040] The present invention will be described below in conjunction with the accompanying drawings.

[0041] The present invention relates to a method for optimizing ship navigation performance considering uncertain variables. The flow chart of the method is as follows: Figure 1 As shown, the following steps are included in sequence:

[0042] 1. Parameter acquisition step: Obtain ship operation parameters and port parameters. Ship operation parameters include actual speed, total mileage, ship still water resistance, wave resistance, wind resistance, hull efficiency, propeller open water efficiency, relative rotation efficiency and shafting efficiency. The total ship resistance is calculated based on the ship's still water resistance, wave resistance and wind resistance. Port parameters include initial departure time and final arrival time. Preferably, ship operation parameters also include propeller wake fraction, thrust reduction fraction, and propeller thrust coefficient and torque coefficient to be corrected.

[0043] Specifically, the total resistance of the ship is calculated based on the ship's still water resistance, wave resistance and wind resistance. The total resistance of the ship is defined as:

[0044] R T =R Calm +R AW +R Wind (1)

[0045] In the above formula, R Calm ,R AW ,R Wind They represent still water resistance, wave resistance (i.e. the additional resistance caused by waves) and wind resistance (i.e. the additional resistance caused by wind) respectively.

[0046] Among them, the hydrostatic resistance of a ship is divided into the following parts:

[0047] R Calm =R F (1+k1)+R APP +R W +R B +R TR +R A (2)

[0048] In the above formula, R F is the friction resistance, (1+k1) is the ratio describing the viscous resistance of the hull and R F The shape factor of the relationship, R APP is the attached resistance, R W is the wave breaking resistance, R B R is the resistance increase of the bulbous bow near the water surface. TR is the added resistance of the square stern immersed part, R A is the relevant resistance of the ship model.

[0049] 1) Friction resistance R F :

[0050]

[0051] In the above formula, C f is the friction coefficient, ΔC fis the roughness compensation coefficient, ρ is the seawater density, V1 is the still water speed, and S is the wet surface area of ​​the ship.

[0052] 2) Attachment resistance R APP :

[0053]

[0054] In the above formula, S APP is the wetted area of ​​the appendage, the appendage resistance coefficient 1+k2 and the ship friction resistance coefficient C f .

[0055] 3) Wave breaking resistance R W :

[0056]

[0057] In the above formula, coefficient c2 is used to represent the partial resistance reduced by the bulbous bow, c5 represents the effect of the square stern on the wave breaking resistance, g is the acceleration of gravity, F n is the Froude number based on the waterline length, and c3 is the coefficient of the effect of the bulbous bow on the wave-breaking resistance.

[0058] 4) Increased resistance of bulbous bow near water surface R B :

[0059]

[0060] In the above formula, P R Used to measure the bow effect, F ni is the Froude number when the bow is immersed.

[0061] 5) Square stern immersion part resistance increase R TR :

[0062]

[0063] In the above formula, A T The cross-sectional area of ​​the submerged part of the stern at rest, m 2 , coefficient c6 and Froude number F when the stern is immersed nT related:

[0064]

[0065] Among them, C WP is the design waterplane coefficient, g is the acceleration of gravity, and B is the ship width.

[0066] 6) Ship model related resistance R A

[0067]

[0068] In the above formula, C A is the correlation coefficient.

[0069] Wind resistance is defined as:

[0070]

[0071] In the above formula, R wind is wind resistance, C wind Represents the air resistance coefficient, which is experimental data, ρ air Represents the air density, which can be 1.226kg / m 3 ; A T Represents the frontal area, m 2 ; V wind Represents relative wind speed, m / s.

[0072]

[0073] In the above formula, V is the actual speed, u w is the wind speed, which can be found through the Beaufort wind scale; is the wind speed u w The angle between the actual speed V and the ship's speed.

[0074] Wave resistance is defined as:

[0075]

[0076] In the above formula, F r is the Froude number (the ratio of the inertial force in the fluid to the gravity), h is the height of the wave, ρ is the density of water, L WL represents the waterline length, S refers to the wetted area of ​​the ship, and V represents the actual speed.

[0077] The Wageningen B-screw (also known as the B-series propeller) is used to evaluate propeller performance. This series includes open fixed pitch propellers with blade area ratios of 0.30-1.05, pitch ratios of 0.5-1.4, and 2-7 blades. The thrust and torque coefficients of the B-series propellers are calculated using the following regression formula:

[0078]

[0079] In the above formula, P is the pitch, J is the speed coefficient, A E is the extended area of ​​the spiral blade, A O is the disk area, Z is the number of blades, and the polynomial regression coefficients of thrust coefficient and torque coefficient are and The power exponents s, t, u, and v of the polynomial regression are obtained based on the data in the Oosterveld article.

[0080] However, it is also necessary to correct the thrust coefficient and torque coefficient of the B series propeller according to the Reynolds number and roughness to obtain the thrust coefficient correction value and torque coefficient correction value; and calculate the actual thrust coefficient K of the propeller according to the thrust coefficient correction value, torque coefficient correction value, and the propeller thrust coefficient and torque coefficient to be corrected. T and the actual torque coefficient K Q , calculated according to the following formula:

[0081]

[0082] Where, ΔC D is the drag coefficient difference of the section. 0.75 is the chord length at 75% of the propeller radius. ΔK T-B and ΔK Q-B They are the correction values ​​of thrust coefficient and torque coefficient of B series propellers respectively.

[0083] The open water efficiency η0 is:

[0084]

[0085] Hull efficiency η H for:

[0086]

[0087] Among them, t m is the thrust reduction fraction, w is the propeller wake fraction, which can be calculated using the Taylor method:

[0088] w=0.5C B -0.05 (18)

[0089] Among them, C B is the square coefficient.

[0090] Relative rotation efficiency η R for:

[0091]

[0092] Among them, A E is the extended area of ​​the spiral blade, A O is the disk area, C P is the diamond coefficient, Lcb is the longitudinal distance of the center of buoyancy.

[0093] The speed coefficient J is expressed as:

[0094]

[0095] Where: D p is the propeller diameter and n is the propeller speed.

[0096] Since the above empirical formula is based on the test data of multiple types of ships and is not targeted at specific ships, the calculation accuracy for specific ships is slightly insufficient and cannot meet the higher calculation accuracy requirements in ship speed optimization. In order to ensure the high accuracy of propeller propulsion performance calculation, the propeller wake fraction and thrust reduction fraction of a specific ship based on ship test data can be used. In the absence of ship test data, the Heckscher method can be used to calculate the thrust reduction fraction:

[0097] t m =0.5C P -0.12 (21)

[0098] Among them, C P is the rhombus coefficient.

[0099] 2. Calculation steps for ship fuel consumption and energy efficiency operation index: Calculate the ship fuel consumption FC based on the total resistance of the ship, total mileage, hull efficiency, propeller open water efficiency, relative rotation efficiency and shafting efficiency, and calculate according to the following formula:

[0100]

[0101] In the above formula, R T is the total resistance of the ship, SFOC is the specific fuel consumption rate of the main engine, D is the total mileage, η H is the hull efficiency, η0 is the open water efficiency, η S is the shafting efficiency, η R is the relative rotation efficiency.

[0102] The ship energy efficiency operation index (EEOI) is calculated based on the ship's fuel consumption (FC), total voyage mileage and total cargo load, and is calculated according to the following formula:

[0103]

[0104] Among them, FC is the ship fuel consumption (i.e. the total amount of fuel consumed by the ship), C F is the carbon dioxide emission factor, m cargo It refers to the cargo (people) load, and D is the total mileage.

[0105] 3. Speed ​​range and objective function establishment steps: Based on the preset expected speed and using the 3sigma criterion, calculate the maximum actual speed and the minimum actual speed respectively, and construct the actual speed range according to the actual speed, the maximum actual speed and the minimum actual speed; then use the actual speed range as a constraint condition, and establish the objective function based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index.

[0106] Specifically, based on the preset expected speed and using the 3sigma criterion, the maximum actual speed and the minimum actual speed are calculated respectively, and the calculation is performed according to the following formula:

[0107] V min =μ V -3σ i (twenty four)

[0108] V max =μ V +3σ i (25)

[0109] Uncertainty constraints are imposed on the actual speed V:

[0110] V min ≤V≤V max (26)

[0111] Among them, V min 、V max The value of is obtained through distribution, μ V is the expected speed, σ i is the standard deviation of the design speed.

[0112] The current design point is randomly disturbed, and a set of sample points are generated near its average value. Then, the reliability and σ level of the output objective function at each design point are statistically analyzed. Reliability refers to the probability of satisfying the design constraints in the design scheme, and the σ level is a quantitative representation of reliability. The speed is defined by the 3sigma criterion, such as Figure 2 As shown. The present invention quantifies the uncertainty of ship speed with the help of a normal model, that is, the uncertainty of ship speed is expressed by a normal model and added to the compiled 3sigma optimization program. The objective function is the target to be optimized. The objective function is divided into the ship energy efficiency operation index EEOI and the ship fuel consumption FC. Therefore, it is a multi-objective optimization. In order to reduce the gap between the values ​​of each objective function, the product form is selected as follows:

[0113] minf(X)=α1EEOU+α2FC (27)

[0114] Among them: α1, α2 are the weights of each target, α1+α2=1.

[0115] 4. The correspondence and calculation steps between the total navigation interval and the total weather array: the navigation interval and weather interval are set based on the time dimension, the total weather array is calculated according to the initial departure time, the final arrival time and the set weather interval, and the total number of navigation intervals is calculated according to the initial departure time, the final arrival time and the set navigation interval; and when the navigation interval and the weather interval are of different sizes, a navigation interval matrix is ​​constructed based on the initial departure time, the navigation interval and the total number of navigation intervals, and the initial departure time and weather interval are combined with at least one of the navigation interval, the total weather array and the total number of navigation intervals to construct a weather interval matrix, and the weather array corresponding to each navigation interval is calculated according to the navigation interval matrix and the weather interval matrix.

[0116] Specifically, we first set the navigation interval and weather interval based on the time dimension, that is, define Dt v ,Dt w The total weather array N is calculated based on the initial departure time, final arrival time and the set weather interval. w , used to store forecast weather data, which is calculated as follows:

[0117]

[0118] Among them, t f is the final arrival time, and t0 is the initial departure time.

[0119] Then calculate the total number of navigation intervals based on the initial departure time, final arrival time and the set navigation interval. The total number of navigation intervals N v Satisfies:

[0120]

[0121] If the entire voyage is divided into i navigation intervals, each navigation interval is defined as:

[0122] [t0+(i-1)Dt v ,t0+iDt v ] i=1,2,…N v , (30)

[0123] Its matrix form is:

[0124]

[0125] Then, when the sizes of the navigation interval and the weather interval are different, a navigation interval matrix is ​​constructed based on the initial departure time, the navigation interval and the total number of navigation intervals, and the initial departure time and weather interval are combined with at least one of the navigation interval, the total weather array and the total number of navigation intervals to construct a weather interval matrix, and the weather array corresponding to each navigation interval is calculated according to the navigation interval matrix and the weather interval matrix.

[0126] Case 1: Flight interval Dt v With weather interval Dt w Equal, k=i=1,2,..,N w (N v ), the navigation interval matrix and weather interval matrix corresponding to the total voyage are as follows:

[0127] WSI i =WSI k =WSI k (v wind ,ψ wind ,H s ,θ waves ) (32)

[0128]

[0129] Case 2: Navigation interval Dt v Weather interval Dt w If large, then i=1,i≤N v <N w ,i++, the weather interval matrix corresponding to each navigation interval is as follows:

[0130]

[0131] Case 3: Navigation interval Dt v Weather interval Dt w Small, k=1, k≤N w <N v ,k++The weather interval matrix corresponding to each navigation interval is as follows:

[0132]

[0133] 5. Parameter initialization step: Set the initial actual speed V of a certain navigation interval within the actual speed value range i , that is, the initialization design variable sequence is:

[0134]

[0135] Then the initial actual speed V iThe weather array corresponding to the navigation interval is used as the initial solution of the simulated annealing algorithm, and the initial objective function value of the navigation interval is calculated according to the initial solution.

[0136] 6. Simulated annealing calculation steps: It is based on the simulated annealing algorithm to optimize the speed V of the flight segment.

[0137] Simulated Annealing (SA) is a random optimization algorithm based on the Monte Carlo iterative solution strategy. Based on the Metropolis criterion, the probability that particles will reach equilibrium during the temperature process is generally e-ΔE / (kT). At this time, E, T, ΔE, and k represent internal energy, temperature, change, and Boltzmann constant, respectively. In the process of simulating combinatorial optimization problems, solid annealing is the main basis. At this time, the objective function value f and the control parameter t correspond to the internal energy E and temperature T. The algorithm obtained in this way can solve combinatorial optimization problems: the first step is to start from the initial value t of the control parameter and the initial solution i. On the basis of this algorithm, the process of "generating a new solution → calculating the objective function difference → accepting or discarding" is not counted. At the same time, the t value is continuously reduced to finally find the optimal solution. This process is actually a random search, which mainly comes from the Monte Carlo iterative solution method.

[0138] like Figure 3 As shown in FIG. 1 , firstly, the candidate solution of the objective function is calculated based on the initial solution and the simulated annealing algorithm is used (i.e., the candidate solution is generated), and it is determined whether the candidate solution is within the actual speed value range (i.e., whether the candidate solution is feasible). If not, the initial actual speed V is reset. i To generate a new candidate solution. If so, the current objective function value is calculated based on the candidate solution, and the current objective function value is compared with the initial objective function value. If the current objective function value is less than the initial objective function value, the candidate solution is used to replace the initial solution, and the candidate solution is used as the new initial solution; if the current objective function value is greater than or equal to the initial objective function value, the initial solution remains unchanged and is used as the new initial solution for the next round of iteration.

[0139] 7. Optimal solution selection and ship navigation performance optimization steps: Repeat the above simulated annealing calculation steps until the preset number of iterations is reached. The new initial solution when the preset number of iterations is reached is used as the optimal solution of the objective function, and the actual speed corresponding to the optimal solution is used as the optimal speed of the navigation interval (that is, the optimal or approximately optimal solution is obtained), and then the optimal speed of each navigation interval is obtained, and the ship's navigation performance is optimized according to the optimal speed of each navigation interval.

[0140] The present invention optimizes the performance of the ship under the uncertainty of the speed factor, reduces the fuel consumption of the ship and the ship energy efficiency operation index EEOI. The uncertainty factors hidden in the ship speed can be found from a large amount of real ship navigation data provided in the database, and the uncertainty of the ship speed can be quantified with the help of the normal model of the 3sigma criterion, and the required navigation performance mathematical model is established, and the navigation performance uncertainty optimization model is established. The uncertainty in the ship operation can be statistically classified first, and the importance of the ship energy efficiency operation index EEOI to it can be verified through the understanding of the ship's navigation performance, and it is used as one of the optimization goals of this project. Among them, a mathematical model of the navigation performance of a real ship is established, in which the still water resistance model uses the classic model of HM (Formula 2), and the Kwon model is used to calculate the speed loss caused by waves, thereby indirectly reflecting the increased resistance of the ship caused by waves (Formula 11), while the wind resistance model adopts the method recommended by ISO15016 (Formula 9). In the fuel consumption model, the propulsion system model of HM is first used, and the thrust coefficient and torque coefficient of the B series propeller are corrected. Finally, the applicability of various fuel consumption models was compared, and it was decided to adopt a fuel consumption model based on the main engine fuel consumption rate, total resistance and sailing distance (Formula 22). Then, the above models were programmed to ensure that the operation results were correct. The uncertainty of speed for design constraints is better, and the speed uncertainty is expressed by a normal model and added to the programmed 3sigma optimization program. A reasonable segment division method was studied, and the overall optimization target was obtained using the segmented sub-intervals. Furthermore, the two optimization algorithms, simulated annealing algorithm and taboo search algorithm, can be combined to obtain the optimal speed that meets the optimization target.

[0141] The present invention also relates to a ship navigation performance optimization system considering uncertain variables, which corresponds to the above-mentioned ship navigation performance optimization method considering uncertain variables, and can be understood as a system for implementing the above-mentioned method. The system includes a parameter acquisition module, a ship fuel consumption and energy efficiency operation index calculation module, a speed value interval and objective function establishment module, a total navigation interval and total weather array correspondence and calculation module, a parameter initialization module, a simulated annealing calculation module, and an optimal solution selection and ship navigation performance optimization module, which are connected in sequence. Specifically,

[0142] The parameter acquisition module acquires ship operation parameters and port parameters. The ship operation parameters include actual speed, total mileage, ship still water resistance, wave resistance, wind resistance, hull efficiency, propeller open water efficiency, relative rotation efficiency and shafting efficiency. The total resistance of the ship is calculated based on the ship's still water resistance, wave resistance and wind resistance. The port parameters include initial departure time and final arrival time.

[0143] The ship fuel consumption and energy efficiency operation index calculation module calculates the ship fuel consumption according to the total resistance of the ship, the total mileage, the hull efficiency, the propeller open water efficiency, the relative rotation efficiency and the shafting efficiency; and then calculates the ship energy efficiency operation index according to the ship fuel consumption, the total mileage and the total cargo load;

[0144] The speed value interval and objective function establishment module calculates the actual speed maximum value and the actual speed minimum value based on the preset expected speed and the 3sigma criterion, and constructs the actual speed value interval according to the actual speed, the actual speed maximum value and the actual speed minimum value; and then uses the actual speed value interval as a constraint condition to establish the objective function based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index;

[0145] The total navigation interval and total weather array correspondence and calculation module sets the navigation interval and weather interval based on the time dimension, calculates the total weather array according to the initial departure time, the final arrival time and the set weather interval, and calculates the total number of navigation intervals according to the initial departure time, the final arrival time and the set navigation interval; and respectively constructs a navigation interval matrix based on the initial departure time, the navigation interval and the total number of navigation intervals when the navigation interval and the weather interval are different in size, and combines the initial departure time and the weather interval with at least one of the navigation interval, the total weather array and the total number of navigation intervals to construct a weather interval matrix, and calculates the weather array corresponding to each navigation interval according to the navigation interval matrix and the weather interval matrix;

[0146] The parameter initialization module sets an initial actual speed of a navigation interval within the actual speed value range, and uses the initial actual speed and the weather array corresponding to the navigation interval as the initial solution of the simulated annealing algorithm, and calculates the initial objective function value of the navigation interval according to the initial solution;

[0147] The simulated annealing calculation module calculates a candidate solution of the objective function according to the initial solution and through the simulated annealing algorithm, and determines whether the candidate solution is within the actual speed value range. If so, the current objective function value is calculated according to the candidate solution, and the current objective function value is compared with the initial objective function value. If the current objective function value is less than the initial objective function value, the initial solution is replaced by the candidate solution, and the candidate solution is used as the new initial solution; if the current objective function value is greater than or equal to the initial objective function value, the initial solution remains unchanged and is used as the new initial solution for the next round of iteration;

[0148] The optimal solution selection and ship navigation performance optimization module repeats the work of the simulated annealing calculation module until a preset number of iterations is reached, and the new initial solution when the preset number of iterations is reached is used as the optimal solution of the objective function, and the actual speed corresponding to the optimal solution is used as the optimal speed of the navigation interval, thereby obtaining the optimal speed of each navigation interval, and optimizing the ship's navigation performance according to the optimal speed of each navigation interval.

[0149] Preferably, in the total navigation interval and total weather array correspondence and calculation module, the initial departure time and weather interval are combined with at least one of the navigation interval, the total weather array and the total navigation interval number to construct the weather interval matrix, specifically including:

[0150] If the navigation interval is equal to the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval and total weather array; if the navigation interval is greater than the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval, navigation interval and total number of navigation intervals; if the navigation interval is less than the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval, navigation interval and total weather array.

[0151] Preferably, the ship operation parameters also include a propeller wake fraction, a thrust deduction fraction, and a propeller thrust coefficient and torque coefficient to be corrected.

[0152] Preferably, the thrust coefficient and the torque coefficient are corrected respectively using the Reynolds number and the roughness to obtain thrust coefficient correction value and torque coefficient correction value respectively; and the actual thrust coefficient and the actual torque coefficient of the propeller are calculated based on the thrust coefficient correction value, the torque coefficient correction value, the propeller thrust coefficient and the torque coefficient to be corrected, and the propeller open water efficiency is calculated based on the actual thrust coefficient and the actual torque coefficient.

[0153] Preferably, the propeller wake fraction is calculated using the Taylor method, and the thrust deduction fraction is calculated using the Heckscher method, and the hull efficiency is calculated based on the propeller wake fraction and the thrust deduction fraction.

[0154] The present invention provides an objective and scientific method and system for optimizing the navigation performance of a ship taking uncertainty variables into consideration. By taking into account the uncertainty of navigation speed caused by operating scenarios, the ship's fuel consumption and the ship's energy efficiency operating index are minimized, and an objective function is established with the navigation speed range as a constraint. At the same time, the weather conditions during the actual navigation of the ship are taken into consideration, and a customized simulated annealing algorithm is designed to obtain the optimal solution of the objective function, which can effectively improve the navigation performance of the ship and reduce costs.

[0155] It should be noted that the above-described specific implementations can enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way. Therefore, although this specification has described the invention in detail with reference to the drawings and embodiments, those skilled in the art should understand that the invention can still be modified or replaced by equivalents. In short, all technical solutions and improvements that do not deviate from the spirit and scope of the invention should be included in the protection scope of the patent for the invention.

Claims

1. A method for optimizing ship navigation performance considering uncertain variables, characterized in that: The following steps are involved: Parameter acquisition step: acquiring ship operation parameters and port parameters, wherein the ship operation parameters include actual speed, total mileage, ship still water resistance, wave resistance, wind resistance, hull efficiency, propeller open water efficiency, relative rotation efficiency and shafting efficiency, and calculating the total resistance of the ship according to the ship still water resistance, wave resistance and wind resistance; the port parameters include initial departure time and final arrival time; Calculation steps for ship fuel consumption and energy efficiency operation index: Calculate the ship fuel consumption based on the total resistance of the ship, total mileage, hull efficiency, propeller open water efficiency, relative rotation efficiency and shafting efficiency; then calculate the ship energy efficiency operation index based on the ship fuel consumption, total mileage and total cargo load; Speed ​​value interval and objective function establishment steps: Based on the preset expected speed and using the 3sigma criterion, the actual speed maximum value and the actual speed minimum value are calculated respectively, and the actual speed value interval is constructed according to the actual speed, the actual speed maximum value and the actual speed minimum value; Then, taking the actual speed range as the constraint condition, the objective function is established based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index; The correspondence and calculation steps of the total navigation interval and the total weather array are as follows: the navigation interval and the weather interval are set based on the time dimension, the total weather array is calculated according to the initial departure time, the final arrival time and the set weather interval, and the total number of navigation intervals is calculated according to the initial departure time, the final arrival time and the set navigation interval; and when the navigation interval and the weather interval are different in size, a navigation interval matrix is ​​constructed based on the initial departure time, the navigation interval and the total number of navigation intervals, and the initial departure time and the weather interval are combined with at least one of the navigation interval, the total weather array and the total number of navigation intervals to construct a weather interval matrix, and the weather array corresponding to each navigation interval is calculated according to the navigation interval matrix and the weather interval matrix; Parameter initialization step: set the initial actual speed of a navigation interval within the actual speed value range, and use the initial actual speed and the weather array corresponding to the navigation interval as the initial solution of the simulated annealing algorithm, and calculate the initial objective function value of the navigation interval based on the initial solution; Simulated annealing calculation steps: According to the initial solution, the candidate solution of the objective function is calculated through the simulated annealing algorithm, and it is determined whether the candidate solution is within the actual speed value range. If so, the current objective function value is calculated according to the candidate solution, and the current objective function value is compared with the initial objective function value. If the current objective function value is less than the initial objective function value, the candidate solution is used to replace the initial solution, and the candidate solution is used as the new initial solution; if the current objective function value is greater than or equal to the initial objective function value, the initial solution remains unchanged and is used as the new initial solution for the next round of iteration; Optimal solution selection and ship navigation performance optimization steps: Repeat the simulated annealing calculation steps until the preset number of iterations is reached. The new initial solution when the preset number of iterations is reached is used as the optimal solution of the objective function, and the actual speed corresponding to the optimal solution is used as the optimal speed of the navigation interval, and then the optimal speed of each navigation interval is obtained, and the ship's navigation performance is optimized according to the optimal speed of each navigation interval.

2. The method for optimizing ship navigation performance considering uncertain variables according to claim 1, characterized in that: In the step of corresponding and calculating the total navigation interval and the total weather array, the initial departure time and the weather interval are combined with at least one of the navigation interval, the total weather array and the total number of navigation intervals to construct a weather interval matrix, which specifically includes: If the navigation interval is equal to the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval and total weather array; if the navigation interval is greater than the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval, navigation interval and total number of navigation intervals; if the navigation interval is less than the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval, navigation interval and total weather array.

3. The method for optimizing ship navigation performance considering uncertain variables according to claim 1, characterized in that: The ship operation parameters also include a propeller wake fraction, a thrust reduction fraction, and a propeller thrust coefficient and a torque coefficient to be corrected.

4. The method for optimizing ship navigation performance considering uncertain variables according to claim 3, characterized in that: The thrust coefficient and torque coefficient are corrected by Reynolds number and roughness respectively, and the thrust coefficient correction value and torque coefficient correction value are obtained respectively; and the actual thrust coefficient and actual torque coefficient of the propeller are calculated according to the thrust coefficient correction value, the torque coefficient correction value, the propeller thrust coefficient and torque coefficient to be corrected, and the propeller open water efficiency is calculated according to the actual thrust coefficient and the actual torque coefficient.

5. The method for optimizing ship navigation performance considering uncertain variables according to claim 3, characterized in that: The propeller wake fraction is calculated by Taylor method, and the thrust reduction fraction is calculated by Heckscher method. The hull efficiency is calculated based on the propeller wake fraction and the thrust reduction fraction.

6. A ship navigation performance optimization system considering uncertain variables, characterized in that: It includes a parameter acquisition module, a ship fuel consumption and energy efficiency operation index calculation module, a speed value range and objective function establishment module, a total navigation range and total weather array correspondence and calculation module, a parameter initialization module, a simulated annealing calculation module, and an optimal solution selection and ship navigation performance optimization module. The parameter acquisition module acquires ship operation parameters and port parameters. The ship operation parameters include actual speed, total mileage, ship still water resistance, wave resistance, wind resistance, hull efficiency, propeller open water efficiency, relative rotation efficiency and shafting efficiency. The total resistance of the ship is calculated based on the ship's still water resistance, wave resistance and wind resistance. The port parameters include initial departure time and final arrival time. The ship fuel consumption and energy efficiency operation index calculation module calculates the ship fuel consumption according to the total resistance of the ship, the total mileage, the hull efficiency, the propeller open water efficiency, the relative rotation efficiency and the shafting efficiency; and then calculates the ship energy efficiency operation index according to the ship fuel consumption, the total mileage and the total cargo load; The speed value interval and objective function establishment module calculates the actual speed maximum value and the actual speed minimum value based on the preset expected speed and adopts the 3sigma criterion, and constructs the actual speed value interval according to the actual speed, the actual speed maximum value and the actual speed minimum value; Then, taking the actual speed range as the constraint condition, the objective function is established based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index; The total navigation interval and total weather array correspondence and calculation module sets the navigation interval and weather interval based on the time dimension, calculates the total weather array according to the initial departure time, the final arrival time and the set weather interval, and calculates the total number of navigation intervals according to the initial departure time, the final arrival time and the set navigation interval; and respectively constructs a navigation interval matrix based on the initial departure time, the navigation interval and the total number of navigation intervals when the navigation interval and the weather interval are different in size, and combines the initial departure time and the weather interval with at least one of the navigation interval, the total weather array and the total number of navigation intervals to construct a weather interval matrix, and calculates the weather array corresponding to each navigation interval according to the navigation interval matrix and the weather interval matrix; The parameter initialization module sets an initial actual speed of a navigation interval within the actual speed value range, and uses the initial actual speed and the weather array corresponding to the navigation interval as the initial solution of the simulated annealing algorithm, and calculates the initial objective function value of the navigation interval according to the initial solution; The simulated annealing calculation module calculates a candidate solution of the objective function according to the initial solution and through the simulated annealing algorithm, and determines whether the candidate solution is within the actual speed value range. If so, the current objective function value is calculated according to the candidate solution, and the current objective function value is compared with the initial objective function value. If the current objective function value is less than the initial objective function value, the initial solution is replaced by the candidate solution, and the candidate solution is used as the new initial solution; if the current objective function value is greater than or equal to the initial objective function value, the initial solution remains unchanged and is used as the new initial solution for the next round of iteration; The optimal solution selection and ship navigation performance optimization module repeats the work of the simulated annealing calculation module until a preset number of iterations is reached, and the new initial solution when the preset number of iterations is reached is used as the optimal solution of the objective function, and the actual speed corresponding to the optimal solution is used as the optimal speed of the navigation interval, thereby obtaining the optimal speed of each navigation interval, and optimizing the ship's navigation performance according to the optimal speed of each navigation interval.

7. The ship navigation performance optimization system considering uncertain variables according to claim 6, characterized in that: In the total navigation interval and total weather array correspondence and calculation module, the initial departure time and weather interval are combined with at least one of the navigation interval, the total weather array and the total navigation interval number to construct the weather interval matrix, specifically including: If the navigation interval is equal to the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval and total weather array; if the navigation interval is greater than the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval, navigation interval and total number of navigation intervals; if the navigation interval is less than the weather interval, the weather interval matrix is ​​constructed based on the initial departure time, weather interval, navigation interval and total weather array.

8. The ship navigation performance optimization system considering uncertain variables according to claim 6, characterized in that: The ship operation parameters also include a propeller wake fraction, a thrust reduction fraction, and a propeller thrust coefficient and a torque coefficient to be corrected.

9. The ship navigation performance optimization system considering uncertain variables according to claim 8, characterized in that: The thrust coefficient and torque coefficient are corrected by Reynolds number and roughness respectively, and the thrust coefficient correction value and torque coefficient correction value are obtained respectively; and the actual thrust coefficient and actual torque coefficient of the propeller are calculated according to the thrust coefficient correction value, the torque coefficient correction value, the propeller thrust coefficient and torque coefficient to be corrected, and the propeller open water efficiency is calculated according to the actual thrust coefficient and the actual torque coefficient.

10. The ship navigation performance optimization system considering uncertain variables according to claim 8, characterized in that: The propeller wake fraction is calculated by Taylor method, and the thrust reduction fraction is calculated by Heckscher method. The hull efficiency is calculated based on the propeller wake fraction and the thrust reduction fraction.

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