Ship dynamic navigational speed optimization method and system considering weather change

Abstract

The invention provides a ship dynamic navigational speed optimization method and system considering weather change, and the method comprises the steps: setting a navigation time interval, a weather time updating interval, a navigation interval multiple and a weather credibility multiple based on a time dimension, and calculating a weather credibility window; storing the weather data of all the weather time updating intervals as a weather data set according to the time sequence, and updating the weather time according to the size relationship between the navigation time interval and the weather time updating intervals; dynamically matching weather data in the weather data set to each sailing time interval of each weather credible window according to a time alignment mode with the sailing time interval to obtain a weather array, and further calculating ship oil consumption and ship energy efficiency operating indexes and establishing a target function; and finally, calculating an optimal solution of the target function by adopting a genetic algorithm or a particle swarm algorithm to obtain an optimal navigational speed and an optimal rotating speed of each navigational time interval in each weather credible window so as to realize full-mileage dynamic navigational speed optimization of the ship.

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 the dynamic speed of a ship taking weather changes into consideration. Background Art

[0002] Due to the global economic recession, climate warming and other adverse effects, the shipping industry is now facing rising fuel prices, which has led to a corresponding increase in ship operating costs. Ships also emit a lot of greenhouse gases, which cause serious damage to the environment, climate and human health. There is a close connection between greenhouse gas emissions in the shipping industry and marine fuel consumption. By optimizing the energy efficiency of marine fuel, not only can marine fuel be made more efficient, but marine fuel consumption can also be effectively reduced, thereby achieving the goal of saving marine fuel and reducing marine fuel consumption. The determination of sailing speed mainly depends on the ship schedule. Due to the uncertainty in maritime logistics, such as random port times and weather conditions, different ship routes have different weather conditions. Therefore, the design and optimization of ship routes have always been a matter of great concern at home and abroad.

[0003] Globally, researchers have begun utilizing various emerging technologies and proposing numerous effective methods to explore effective navigation management. For example, the American company AWT has launched the weather-based route planning software BVS, which can significantly save costs and sailing time. Ship engine fuel consumption prediction models and optimization algorithms are the two core elements of ship speed optimization. Current ship speed optimization research typically constructs principle models based on ship propulsion principles to calculate engine fuel consumption. This makes it difficult to accurately account for the effects of wind, waves, and currents, resulting in large errors in fuel consumption calculations. Furthermore, in-depth research on optimal route segmentation and accurate weather loading, which are closely related to speed optimization, is rarely explored, resulting in limited practicality and accuracy of speed optimization algorithms. Furthermore, traditional non-dynamic ship speed optimization methods have the following drawbacks: 1) Weather conditions must be predicted in advance at the start of optimization, and while the predicted weather data is 100% reliable, weather data can vary during actual ship navigation. 2) In a non-dynamic optimization process, the more segmentation intervals, the more design variables there are, leading to computational complexity and algorithmic difficulties.

[0004] In summary, traditional non-dynamic optimization cannot meet the minimum fuel consumption and ship energy efficiency operation index (EEOI). In the face of future challenges, the shipping industry needs to continue to explore and apply new technologies and methods to cope with the ever-changing environment and market demands. Summary of the Invention

[0005] To address the current challenges of ship speed optimization, such as the need to predict weather conditions in advance and the resulting computational complexity, the present invention provides a dynamic ship speed optimization method that accounts for weather changes. By dynamically matching sailing time intervals with weather data, this method more accurately reflects weather changes during actual sailing, significantly reducing fuel consumption and EEOI values. This allows fleets to achieve efficient operations and improve overall transport efficiency. The use of a segmented optimization design reduces computational complexity, improves the algorithm's practicality and real-time performance, and achieves dynamic optimization of ship speed and rotational speed. The present invention also relates to a dynamic ship speed optimization system that accounts for weather changes.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for optimizing ship dynamic speed considering weather changes, characterized by comprising the following steps:

[0008] Parameter acquisition and total voyage time calculation steps: obtaining ship operating parameters and port parameters, wherein the ship operating parameters include actual speed, actual rotation speed, total mileage, ship still water resistance, total cargo load, hull efficiency, relative rotation efficiency, and shafting efficiency; and the port parameters include initial departure time and final arrival time; and calculating the total voyage time based on the initial departure time and final arrival time;

[0009] Calculation steps for the sub-problem to be optimized: set the navigation time interval and weather time update interval based on the time dimension, set the navigation interval multiple for the navigation time interval, and set the weather credibility multiple for the weather time update interval; calculate the weather credibility window based on the navigation time interval and the weather credibility multiple, and calculate the navigation interval based on the navigation time interval and the navigation interval multiple; calculate the total number of weather time update intervals based on the total navigation time and the set weather time update interval, and calculate the total number of navigation intervals based on the total navigation time, navigation interval, navigation interval multiple, and weather credibility multiple, and then treat each navigation interval as a sub-problem to be optimized, resulting in multiple sub-problems to be optimized;

[0010] Dynamic matching steps between flight time intervals and weather data: obtain weather data for each weather time update interval, and store the weather data for all weather time update intervals in chronological order as a weather dataset; then, based on the size relationship between the flight time intervals and the weather time update intervals, dynamically match the weather data in the weather dataset to each flight time interval of each sub-problem to be optimized in a manner that is aligned in time with the flight time interval, thus obtaining a weather array that matches each flight time interval in each sub-problem to be optimized;

[0011] Calculation steps for ship fuel consumption and ship energy efficiency operation index: Initialize the actual speed and actual speed of each sailing time interval in each sub-problem to be optimized to generate a speed sequence and a speed sequence; calculate the wind resistance and wave resistance based on the initialized actual speed and the matching weather array, and calculate the propeller open water efficiency based on the initialized actual speed and actual speed; calculate the total ship resistance based on the ship's still water resistance, wind resistance, and wave resistance; calculate the ship's fuel consumption based on the total ship resistance, total sailing mileage, propeller open water efficiency, hull efficiency, relative rotation efficiency, and shafting efficiency; and then calculate the ship's energy efficiency operation index based on the ship's fuel consumption, total sailing mileage, and total cargo load;

[0012] Objective function establishment steps: constructing an actual speed value interval based on the actual maximum speed value and the actual minimum speed value in the speed sequence, and constructing an actual speed value interval based on the actual speed maximum value and the actual speed minimum value in the speed sequence; under multiple constraint conditions established with the actual speed value interval, the actual speed value interval and the preset target distance limit as constraints, establishing a first objective function for each of the remaining sub-problems to be optimized except the last sub-problem to be optimized based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index; and establishing a second objective function for the last sub-problem to be optimized based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index under multiple constraint conditions established with the actual speed value interval and the actual speed value interval as constraints;

[0013] Optimal solution calculation and dynamic speed optimization steps: Genetic algorithm or particle swarm algorithm is used to calculate the optimal solutions of each first objective function and second objective function respectively, and the optimal speed and optimal rotation speed of each navigation time interval in each sub-problem to be optimized are obtained, thereby minimizing the ship's fuel consumption and the ship's energy efficiency operation index, and realizing dynamic speed optimization of the ship's full mileage.

[0014] Preferably, in the step of dynamically matching the flight time intervals with the weather data, dynamically matching the weather data in the weather dataset to each flight time interval of each sub-problem to be optimized in a manner that is temporally aligned with the flight time interval according to the size relationship between the flight time interval and the weather time update interval specifically includes:

[0015] If the flight time interval is equal to the weather time update interval, the weather data of any weather time update interval in the weather dataset is dynamically matched to the flight time interval that is aligned with the weather time update interval;

[0016] If the flight interval is longer than the weather interval, multiple consecutive weather time update intervals in the weather data set are merged with the same time length as any flight time interval to obtain multiple merged weather time segments, and the weather data of any merged weather time segment is dynamically matched to the flight time interval that is aligned with the weather time segment in time;

[0017] If the navigation interval is smaller than the weather interval, all weather time update intervals in the weather data set are divided equally according to the same time length as any navigation time interval to obtain multiple equally divided weather time segments, and the weather data of any equally divided weather time segment is dynamically matched to the navigation interval that is aligned in time with the weather time segment.

[0018] Preferably, in the parameter acquisition and total sailing time calculation steps, the ship operating parameters also include propeller thrust coefficient and torque coefficient to be corrected, windward area, waterline length, ship's wetted area and propeller diameter.

[0019] Preferably, in the step of calculating the ship fuel consumption and the ship energy efficiency operation index, the Reynolds number and the roughness are used to correct the propeller thrust coefficient and the torque coefficient to be corrected, respectively, to obtain the thrust coefficient correction value and the 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.

[0020] Preferably, in the ship fuel consumption and ship energy efficiency operation index calculation step, respectively calculating the wind resistance and wave resistance based on the initialized actual speed and in combination with the matched weather array specifically includes:

[0021] The relative wind speed is calculated based on the initialized actual speed and the wind speed and wind direction in the weather array, and the wind resistance is calculated based on the relative wind speed and windward area; the wave resistance is calculated based on the initialized actual speed, the wave height, waterline length and wetted area of ​​the ship in the weather array;

[0022] Calculating the propeller open water efficiency based on the initialized actual ship speed and actual rotational speed specifically includes: calculating the advance coefficient based on the initialized actual ship speed, actual rotational speed and propeller diameter, and calculating the propeller open water efficiency based on the actual thrust coefficient, actual torque coefficient and advance coefficient.

[0023] Preferably, in the objective function establishment step, the average speed is also calculated based on the total mileage and the total voyage time, and the multiple constraints include a first constraint established with the actual speed value range as a constraint, a second constraint established with the actual speed value range as a constraint, and a third constraint established with the preset target distance limit as a constraint; the first constraint is constructed based on the actual speed and the actual speed value range, the second constraint is constructed based on the actual speed and the actual speed value range, and the third constraint is constructed based on the initial cumulative voyage distance from the starting point of the first sub-problem to be optimized to the starting point of the current sub-problem to be optimized, the cumulative voyage distance from the starting point of the first sub-problem to be optimized to the end point of the current sub-problem to be optimized, the average speed, the voyage time interval and the weather credibility multiple.

[0024] A ship dynamic speed optimization system considering weather changes is characterized by comprising a parameter acquisition and total sailing time calculation module, a sub-problem calculation module to be optimized, a sailing time interval and weather data dynamic matching module, a ship fuel consumption and ship energy efficiency operation index calculation module, an objective function establishment module, and an optimal solution calculation and dynamic speed optimization module connected in sequence.

[0025] The parameter acquisition and total sailing time calculation module acquires ship operating parameters and port parameters. The ship operating parameters include actual speed, actual rotation speed, total sailing mileage, ship still water resistance, total cargo load, hull efficiency, relative rotation efficiency and shafting efficiency. The port parameters include initial departure time and final arrival time; the total sailing time is calculated based on the initial departure time and final arrival time.

[0026] The sub-problem calculation module to be optimized sets a navigation time interval and a weather time update interval based on the time dimension, sets a navigation interval multiple for the navigation time interval, and sets a weather credibility multiple for the weather time update interval; calculates a weather credibility window based on the navigation time interval and the weather credibility multiple, and calculates the navigation interval based on the navigation time interval and the navigation interval multiple; calculates the total number of weather time update intervals based on the total navigation time and the set weather time update interval, and calculates the total number of navigation intervals based on the total navigation time, the navigation interval, the navigation interval multiple, and the weather credibility multiple, and then treats each navigation interval as a sub-problem to be optimized, thereby obtaining multiple sub-problems to be optimized;

[0027] The module for dynamically matching flight time intervals with weather data obtains weather data for each weather time update interval and stores the weather data for all weather time update intervals in chronological order as a weather data set. The module then dynamically matches the weather data in the weather data set to each flight time interval of each subproblem to be optimized in a manner that aligns the weather data with the flight time interval based on the size relationship between the flight time interval and the weather time update interval, thereby obtaining a weather array that matches each flight time interval in each subproblem to be optimized.

[0028] The ship fuel consumption and ship energy efficiency operation index calculation module initializes the actual speed and actual speed of each sailing time interval in each sub-problem to be optimized, generates a speed sequence and a speed sequence; calculates the wind resistance and wave resistance based on the initialized actual speed and combined with the matching weather array, and calculates the propeller open water efficiency based on the initialized actual speed and actual speed; calculates the total ship resistance based on the ship's still water resistance, wind resistance and wave resistance, and calculates the ship's fuel consumption based on the total ship resistance, total mileage, propeller open water efficiency, hull efficiency, relative rotation efficiency and shafting efficiency; and then calculates the ship's energy efficiency operation index based on the ship's fuel consumption, total mileage and total cargo load;

[0029] The objective function establishment module constructs an actual speed value interval based on the actual speed maximum value and the actual speed minimum value in the speed sequence, and constructs an actual speed value interval based on the actual speed maximum value and the actual speed minimum value in the speed sequence; under multiple constraints established with the actual speed value interval, the actual speed value interval and the preset target distance limit as constraints, a first objective function is established for each of the remaining sub-problems to be optimized except the last sub-problem to be optimized based on a preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index; and under multiple constraints established with the actual speed value interval and the actual speed value interval as constraints, a second objective function is established for the last sub-problem to be optimized based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index;

[0030] The optimal solution calculation and dynamic speed optimization module uses a genetic algorithm or a particle swarm algorithm to calculate the optimal solutions of each first objective function and the second objective function respectively, and obtains the optimal speed and optimal rotation speed for each sailing time interval in each sub-problem to be optimized, thereby minimizing the ship's fuel consumption and the ship's energy efficiency operation index, and realizing dynamic speed optimization of the ship's full mileage.

[0031] Preferably, in the module for dynamically matching flight time intervals with weather data, dynamically matching weather data in the weather data set to each flight time interval of each sub-problem to be optimized in a manner that is aligned in time with the flight time interval according to the size relationship between the flight time interval and the weather time update interval specifically includes:

[0032] If the flight time interval is equal to the weather time update interval, the weather data of any weather time update interval in the weather dataset is dynamically matched to the flight time interval that is aligned with the weather time update interval;

[0033] If the flight interval is longer than the weather interval, multiple consecutive weather time update intervals in the weather data set are merged with the same time length as any flight time interval to obtain multiple merged weather time segments, and the weather data of any merged weather time segment is dynamically matched to the flight time interval that is aligned with the weather time segment in time;

[0034] If the navigation interval is smaller than the weather interval, all weather time update intervals in the weather data set are divided equally according to the same time length as any navigation time interval to obtain multiple equally divided weather time segments, and the weather data of any equally divided weather time segment is dynamically matched to the navigation interval that is aligned in time with the weather time segment.

[0035] Preferably, in the parameter acquisition and total sailing time calculation module, the ship operation parameters further include propeller thrust coefficient and torque coefficient to be corrected, windward area, waterline length, ship's wetted area and propeller diameter;

[0036] In the ship fuel consumption and ship energy efficiency operation index calculation module, the Reynolds number and roughness are used to correct the propeller thrust coefficient and torque coefficient to be corrected, respectively, to obtain a thrust coefficient correction value and a torque coefficient correction value, respectively; and the actual thrust coefficient and actual torque coefficient of the propeller are calculated based on the thrust coefficient correction value, the torque coefficient correction value, and the propeller thrust coefficient and torque coefficient to be corrected.

[0037] Preferably, in the ship fuel consumption and ship energy efficiency operation index calculation module, the wind resistance and wave resistance are calculated based on the initialized actual speed and in combination with the matched weather array, specifically including:

[0038] The relative wind speed is calculated based on the initialized actual speed and the wind speed and wind direction in the weather array, and the wind resistance is calculated based on the relative wind speed and windward area; the wave resistance is calculated based on the initialized actual speed, the wave height, waterline length and wetted area of ​​the ship in the weather array;

[0039] Calculating the propeller open water efficiency based on the initialized actual ship speed and actual rotational speed specifically includes: calculating the advance coefficient based on the initialized actual ship speed, actual rotational speed and propeller diameter, and calculating the propeller open water efficiency based on the actual thrust coefficient, actual torque coefficient and advance coefficient.

[0040] The beneficial effects of the present invention are:

[0041] The present invention provides a method for optimizing the dynamic speed of a ship considering weather changes. The method first obtains ship operating parameters and port parameters, and sets a sailing time interval and a weather time update interval based on the time dimension, sets a sailing interval multiple for the sailing time interval, and sets a weather credibility multiple for the weather time update interval, and then calculates the total number of sailing intervals. Each sailing interval is then taken as a sub-problem to be optimized, and multiple sub-problems to be optimized are obtained. The weather data of each weather time update interval is obtained, and the weather data of all weather time update intervals are stored in chronological order as a weather data set (which can be understood as a global weather array). Then, according to the size relationship between the sailing time interval and the weather time update interval, the weather data is calculated according to the weather data set. The sailing time intervals are aligned in time to dynamically match the weather data in the weather array to the sailing time intervals of each sub-problem to be optimized, and a weather array that matches the sailing time intervals in each sub-problem to be optimized is obtained (which can be understood as a local weather array that matches the sub-problem); by setting reasonable sailing time intervals and weather time update intervals, and adopting specific methods to achieve accurate matching of weather data with the sailing time intervals in each optimization sub-problem, the ship can adopt the most appropriate speed strategy under real-time changing weather conditions, improve energy efficiency, and ensure that the ship always adjusts its speed according to the latest weather information during the entire sailing process to minimize fuel consumption. Then the ship fuel consumption and ship energy efficiency operation index are calculated, and then the actual speed value range, the actual speed value range and the preset target distance limit are used as constraints. Based on the preset weight coefficient, ship fuel consumption and ship energy efficiency operation index, the first objective function is established for each sub-problem to be optimized except the last sub-problem to be optimized. Under multiple constraints established with the actual speed value range and the actual speed value range as constraints, the second objective function for the last sub-problem to be optimized is established based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index. Finally, the genetic algorithm or particle swarm algorithm is used to calculate the first objective function of each sub-problem. The optimal solution of the second objective function is obtained to obtain the optimal speed and optimal rotation speed for each sailing time interval in each sub-problem to be optimized, thereby minimizing the ship's fuel consumption and the ship's energy efficiency operation index, and realizing dynamic speed optimization of the ship's full mileage. By fully considering the fact that the meteorological data of the merchant ship in the last sub-problem to be optimized may be insufficient, a separate optimization is performed for the incomplete terminal interval to avoid the total fuel consumption or EEOI deviation caused by ignoring the remaining voyage. At the same time, the weather data and constraints of the last sub-problem to be optimized are dynamically adjusted to adapt to the uncertainty in actual navigation, ensuring that the ship maintains optimal energy efficiency in the final section before reaching its destination.Through segmented optimization and terminal correction, the overall optimality of the full-process speed strategy in terms of time and energy efficiency is ensured, and the ship is ensured to always operate at the optimal speed and rotation speed throughout the entire voyage, which significantly reduces fuel consumption and greenhouse gas emissions, improves the overall operational efficiency of the ship, and also contributes to environmental protection.

[0042] Furthermore, in the step of dynamically matching the navigation time interval with the weather data, according to the size relationship between the navigation time interval and the weather time update interval, the weather data in the weather data set are dynamically matched to each navigation time interval of each sub-problem to be optimized in a manner that is aligned in time with the navigation time interval. Specifically, if the navigation time interval is equal to the weather time update interval, the weather data of any weather time update interval in the weather data set is dynamically matched to the navigation time interval that is aligned in time with the weather time update interval; if the navigation interval is larger than the weather interval, multiple weather time update intervals that are adjacent in sequence in the weather data set are merged according to the same time length as any navigation time interval to obtain multiple merged weather time intervals. Segments, and dynamically match the weather data of any merged weather time segment to the navigation time interval that is aligned in time with the weather time segment; if the navigation interval is smaller than the weather interval, all weather time update intervals in the weather data set are evenly divided according to the same time length as any navigation time interval to obtain multiple equally divided weather time segments, and dynamically match the weather data of any equally divided weather time segment to the navigation interval that is aligned in time with the weather time segment. The navigation time interval is dynamically matched with the weather data through segmented adjustment, ensuring that the ship always adjusts its speed according to the latest weather information during the entire navigation process, which can more accurately reflect the weather changes in the actual navigation and minimize fuel consumption.

[0043] Furthermore, the Reynolds number and roughness are used to correct the propeller thrust coefficient and torque coefficient to be corrected, respectively, and the thrust coefficient correction value and torque coefficient correction value are obtained respectively. The actual thrust coefficient and 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 torque coefficient to be corrected, which can more accurately reflect the performance of the propeller under actual working conditions, and the corrected thrust coefficient and torque coefficient can better adapt to various complex environments, making the model more universal and robust, which not only improves the accuracy of the theoretical model, but also provides a more reliable basis for the design, operation and maintenance of ships, and has significant technical and economic benefits.

[0044] Furthermore, in the ship fuel consumption and ship energy efficiency operation index calculation step, the wind resistance and wave resistance are calculated based on the initialized actual speed and combined with the matching weather array, specifically including: calculating the relative wind speed based on the initialized actual speed and the wind speed and wind direction in the weather array, calculating the wind resistance based on the relative wind speed and the windward area, quantifying the effect of wind on the resistance of the ship, and avoiding the error of ignoring the wind direction or simplifying the drag coefficient in the traditional method; calculating the wave resistance based on the initialized actual speed, the wave height, waterline length and wetted area of ​​the ship in the weather array, accurately reflecting the fluid dynamic interference of the wave on the hull, and avoiding underestimating the main engine power demand; calculating the propeller open water efficiency based on the initialized actual speed and actual speed, specifically including: calculating the advance coefficient based on the initialized actual speed, actual speed and propeller diameter to identify whether the propeller is in the efficient working range, avoid inefficient working conditions (such as idling or overload), and calculating the propeller open water efficiency based on the actual thrust coefficient, actual torque coefficient and advance coefficient to reduce invalid energy consumption.

[0045] The present invention achieves dynamic optimization of ship speed and rotation speed by dynamically dividing voyage intervals, loading weather data in real time, and combining intelligent optimization algorithms (such as genetic algorithms, dynamic matching optimization strategies, etc.). By dynamically matching voyage time intervals with weather data, it can more accurately reflect weather changes during actual voyages, significantly reducing fuel consumption and EEOI values, while ensuring that ships arrive at their destinations on time, enabling fleets to achieve efficient operations and improve overall transportation efficiency. This will bring many benefits, including reducing operating costs, increasing dry bulk cargo transshipment volume, reducing empty travel and waiting time, and reducing energy consumption and environmental pollution. It can also help fleets achieve efficient operations, maximize profits, and achieve improved transportation efficiency, solving the problem that traditional non-dynamic optimization cannot meet the minimum fuel consumption and ship energy efficiency operation index (EEOI) requirements of ships. In addition, the segmented optimization design reduces computational complexity, improves the practicality and real-time performance of the algorithm, and provides an efficient and feasible solution for energy conservation and emission reduction in the shipping industry.

[0046] The present invention also relates to a dynamic ship speed optimization system that takes weather changes into account. The system corresponds to the above-mentioned dynamic ship speed optimization method that takes weather changes into account, and can be understood as a system that implements the above-mentioned dynamic ship speed optimization method that takes weather changes into account. The system includes a parameter acquisition and total sailing time calculation module, a sub-problem calculation module to be optimized, a sailing time interval and weather data dynamic matching module, a ship fuel consumption and ship energy efficiency operation index calculation module, an objective function establishment module, and an optimal solution calculation and dynamic speed optimization module that are connected in sequence. The modules work together to more accurately reflect weather changes in actual sailing by dynamically matching sailing time intervals with weather data, significantly reducing fuel consumption and EEOI values, while ensuring that ships arrive at their destinations on time, so that the fleet can achieve efficient operation and improve overall transportation efficiency. This will bring many benefits, including reducing operating costs, increasing dry bulk cargo transshipment volume, reducing empty driving and waiting time, and reducing energy consumption and environmental pollution. At the same time, it can also help the fleet achieve efficient operation, maximize profits and achieve improved transportation efficiency. In addition, the segmented optimization design reduces computational complexity, improves the practicality and real-time performance of the algorithm, and provides an efficient and feasible solution for energy conservation and emission reduction in the shipping industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The present invention is a flow chart of a method for optimizing the dynamic speed of a ship taking weather changes into consideration.

[0048] Figure 2 This is a preferred flow chart of the method for optimizing the dynamic speed of a ship taking weather changes into consideration according to the present invention.

[0049] Figure 3 This invention Dt v =Dt w Schematic diagram of meteorological data extraction at this time.

[0050] Figure 4 This invention Dt v >Dt w Schematic diagram of meteorological data extraction at this time.

[0051] Figure 5 This invention Dt v <Dt w Schematic diagram of meteorological data extraction at this time.

[0052] Figure 6 This is a schematic diagram of calculating the ship energy efficiency operation index and ship fuel consumption according to the present invention.

[0053] Figure 7 Schematic diagram of target distance constraint of the present invention.

[0054] Figure 8 This invention max Optimization schematic diagram.

[0055] Figure 9 It is a schematic diagram of the dynamic optimization strategy of the present invention. DETAILED DESCRIPTION

[0056] The present invention will be described below with reference to the accompanying drawings.

[0057] The present invention relates to a method for optimizing ship dynamic speed considering weather changes. The flow chart of the method is as follows: Figure 1 As shown, the following steps are included in sequence:

[0058] 1. Parameter Acquisition and Total Voyage Time Calculation Steps: Obtain vessel operating parameters and port parameters. Vessel operating parameters include actual speed, actual rotational speed, total mileage, vessel's hydrostatic resistance, total cargo load, hull efficiency, relative rotational efficiency, and shafting efficiency. Port parameters include initial departure time and final arrival time. Preferably, vessel operating parameters also include propeller thrust and torque coefficients to be corrected, windward area, waterline length, vessel's wetted area, and propeller diameter.

[0059] 2. Calculation steps for the sub-problems to be optimized: set the navigation time interval and weather time update interval based on the time dimension, set the navigation interval multiple for the navigation time interval, and set the weather credibility multiple for the weather time update interval; calculate the weather credibility window according to the navigation time interval and the weather credibility multiple, and calculate the navigation interval according to the navigation time interval and the navigation interval multiple; calculate the total number of weather time update intervals according to the total navigation time and the set weather time update interval, and calculate the total number of navigation intervals according to the total navigation time, navigation interval, navigation interval multiple and weather credibility multiple, and then treat each navigation interval as a sub-problem to be optimized, and obtain multiple sub-problems to be optimized.

[0060] Specifically, if Figure 2 As shown, firstly, the navigation time interval Dt is set based on the time dimension v And weather time update interval Dt w , that is, define Dt v ,Dt w They are respectively the navigation time interval and the weather time update interval, and the weather credibility multiple n is set for the weather time update interval a , set the navigation interval multiple n for the navigation time interval b ; Based on the initial departure time t0 and the final arrival time t f Calculate the total voyage time, that is, define the total voyage time as T s =t f -t0, and and Take an integer, that is, determine whether mod(T s ,Dtw )=0,mod(T s ,Dt v )=0; Calculate the weather credible window T according to the navigation time interval and the weather credible multiple a , that is, the weather credible interval is defined as T a =n a ×Dt v ; Calculate the navigation interval based on the navigation time interval and the navigation interval multiple, that is, define the navigation interval as T b =n b Dt v ,and and Take an integer, n a ≥n b .

[0061] First determine the total navigation time T s Divide by the weather time update interval Dt w Is the remainder 0, that is, mod(T s , Dt w )=0, to ensure that the time point of weather data update can fully cover the entire voyage and avoid the "half-cut" weather interval. And determine the total voyage time T s Divide by the flight time interval Dt v Is the remainder 0, that is, mod(T s , Dt v )=0, to ensure that the time segment of speed optimization can evenly cover the entire journey and avoid the remaining unoptimized fragmented time at the end. s , Dt w )=0 and mod(T s , Dt v )=0, then redefine Dt v and Dt w ; If mod(T s , Dt w )=0 and mod(T s , Dt v )=0, then update the interval Dt according to the total navigation time and the set weather time w Calculate the weather time update interval Dt w The total number N w , that is, define the number of weather conditions N w for:

[0062]

[0063] And according to the total sailing time and the set sailing time interval Dt v Calculate the flight time interval Dt vThe total number of speed segment intervals N v for:

[0064]

[0065] Then determine the weather credible window T a Divide by the weather time update interval Dt w Is the remainder 0, that is, mod(T a , Dt w )=0, to ensure that the weather is reliable within the window T a The weather data update times are complete (no incomplete interval). And the navigation interval T b Divide by the weather time update interval Dt w Is the remainder 0, that is, mod(T b , Dt w )=0, ensuring that the weather data used in each sub-problem optimization can be aligned with the latest update time. If mod(T a , Dt w )=0 and mod(T b , Dt w )=0, then redefine n a 、n b 、T a and T b , if mod(T a , Dt w )=0 and mod(T b , Dt w )=0, the total number of flight intervals j is calculated based on the total flight time, flight interval, flight interval multiple and weather credibility multiple. max , and then take each navigation interval as a sub-problem to be optimized (that is, the length of each sub-problem to be optimized is n b *Dt v ), we get multiple sub-problems to be optimized, namely, the ship leaves port A (the initial departure time is t0) and arrives at port B (the final arrival time is t f ), the number of single continuous optimization subproblems j can be calculated max for:

[0066]

[0067] In the above formula, ceil represents a function that rounds to the nearest integer value.

[0068] 3. Dynamic matching steps of navigation time intervals and weather data: obtain the weather data of each weather time update interval, and store the weather data of all weather time update intervals as a weather dataset in chronological order; then, according to the size relationship between the navigation time interval and the weather time update interval, dynamically match the weather data in the weather dataset to each navigation time interval of each sub-problem to be optimized in a way that is aligned in time with the navigation time interval, and obtain a weather array that matches each navigation time interval in each sub-problem to be optimized.

[0069] Specifically, first prepare an empty weather array for storing weather data, which is an empty array. The stored weather data includes wind speed v wind 、wind direction ψ wind , wave height H s and wave direction θ waves Then get each weather time update interval Dt w The weather data of all weather time update intervals are stored in chronological order as a weather array. For example, each weather time update interval Dt is stored in chronological order. w (such as Dt w =1 hour) weather data (wind speed v wind 、wind direction ψ wind , wave height H s and wave direction θ waves ) is stored as a weather dataset or global weather array, and each weather time update interval is taken as a time point t w,k , the time point t corresponding to the weather time update interval w,k It can be expressed as:

[0070]

[0071] Therefore, the weather dataset WSO is represented as:

[0072]

[0073] Among them, the weather data of the ship is in the navigation interval t f -t0-n a Dt v If , then the jth sub-problem to be optimized is:

[0074] t f -t0≥n a Dt v +(j m -1)n b Dt v

[0075] t f -t0≤n a Dtv +j m n b Dt v

[0076] Where, j m =j max -1;

[0077] satisfy:

[0078]

[0079] But for the last sub-problem to be optimized j max =j m +1, because the weather data for merchant ships may be insufficient, special consideration is needed. Finally, it can be concluded that:

[0080]

[0081] In addition, the distance that the ship completes in the jth sub-problem to be optimized is defined as S 0,j ; Define the sailing time for the ship to complete j sub-problems at the beginning as t 0,j ; When j = 1, then S 0,1 =0,t 0,1 =t0.

[0082] If j≤j m =j max -1, intercept weather data WSI j for:

[0083]

[0084] Number n w Defined as:

[0085]

[0086] In the interval [t 0,j +(k-1)Dt w ,t 0,j +kDt w ] is represented as:

[0087]

[0088] Then, based on the size relationship between the flight time interval and the weather time update interval, the weather data in the weather data set is dynamically matched to each flight time interval of each sub-problem to be optimized in a manner that is aligned in time with the flight time interval, thereby obtaining a weather array that matches each flight time interval in each sub-problem to be optimized. Preferably, if the flight time interval is equal to the weather time update interval, the weather data in any weather time update interval in the weather data set is dynamically matched to the flight time interval that is aligned in time with the weather time update interval; that is, a one-to-one mapping. For example, if the flight time interval is [8:00, 9:00], the weather data in the weather array is directly matched to the flight time interval that is aligned in time with the weather time update interval. w,r =8:00 weather data; if the flight interval is greater than the weather time update interval, multiple weather time update intervals in the weather data set that are adjacent in sequence are merged according to the same time length as any flight time interval to obtain multiple merged weather time segments, and the weather data of any merged weather time segment is dynamically matched to the flight time interval that is aligned with the weather time segment in time; that is, multiple weather time update interval data are aggregated, for example, if Dt v =4 hours, Dt w = 1 hour, then aggregate 4 weather data (i.e., weather data of 4 weather time update intervals) for matching. If the flight interval is smaller than the weather time update interval, then all weather time update intervals in the weather data set are evenly divided according to the same time length as any flight time interval to obtain multiple evenly divided weather time segments, and dynamically match the weather data of any evenly divided weather time segment to the flight interval that is aligned with the weather time segment in time; that is, split the weather data, for example, if Dt w =4 hours, Dt v = 1 hour, the weather time update interval is split into four 1-hour weather time segments, and the 1-hour weather segments are used for matching.

[0089] Specifically, according to Dt v ,Dt w The relationship mapping weather data, if 1≤j≤j max -1, then the subproblem of navigation j is expressed in terms of i as:

[0090] [t 0,j +(i-1)Dt v ,t 0,j +iDt v ]i=1,2,…n a

[0091] It can be expressed in matrix form as:

[0092]

[0093] 1) If Figure 3 As shown, when Dt v =Dt w When k=i=1,2,..,n a , intercept meteorological data WSI j The formula is:

[0094]

[0095]

[0096] 2) If Figure 4 As shown, when Dt v >Dt w When i=1,i≤n a ,i++, interval = i×Dt v ,but:

[0097]

[0098]

[0099] In form it expands to:

[0100] When i=1:

[0101]

[0102] When i=2:

[0103]

[0104] t 0,j +(k-1)Dt w ,t 0,j +k Dt w ],WSI 2,j =WSI k,j ,

[0105]

[0106]

[0107] When i=3:

[0108]

[0109] …

[0110] When i is the general case:

[0111]

[0112] t 0,j +(k-1)Dt w,t 0,j +k Dt w ],WSI i,j =WSI k,j ,

[0113]

[0114] …

[0115] when i=n a hour:

[0116]

[0117] …

[0118] 3) If Figure 5 As shown, when Dt v <Dt w hour, k++, then:

[0119]

[0120]

[0121] In form it expands to:

[0122] When k=1:

[0123]

[0124] When k=2:

[0125]

[0126] [t 0,j +(i-1)Dt v ,t 0,j +i Dt v ],WSI i,j =WSI 2,j ,

[0127]

[0128] When k=3:

[0129]

[0130] [t 0,j +(i-1)Dt v ,t 0,j +i Dt v ],WSI i,j =WSI 3,j ,

[0131]

[0132] …

[0133] When k is the general case:

[0134]

[0135] [t 0,j +(i-1)Dt v ,t 0,j +i Dt v ],WSI i,j =WSI k,j ,

[0136]

[0137] …

[0138] When k=n r hour:

[0139]

[0140] …

[0141] 4. Calculation steps for ship fuel consumption and ship energy efficiency operation index: Initialize the actual speed and actual rotation speed of each sailing time interval in each sub-problem to be optimized, and generate a speed sequence and a rotation speed sequence; calculate the wind resistance and wave resistance based on the initialized actual speed and combined with the matching weather array, and calculate the propeller open water efficiency based on the initialized actual speed and actual rotation speed; calculate the total resistance of the ship based on the ship's still water resistance, wind resistance and wave resistance, and calculate the ship's fuel consumption based on the total resistance of the ship, total sailing mileage, propeller open water efficiency, hull efficiency, relative rotation efficiency and shafting efficiency; and then calculate the ship's energy efficiency operation index based on the ship's fuel consumption, total sailing mileage and total cargo load.

[0142] Specifically, first initialize the actual speed and actual rotation speed of each navigation time interval in each weather credible window to generate the speed sequence V and rotation speed sequence N, that is, initialize the design speed and rotation speed sequence of sub-problem j:

[0143]

[0144] Satisfy the constraints:

[0145] V min ≤V i,j ≤V max N min ≤N i,j ≤N max

[0146] Then, based on the initialized actual speed and the matching weather array, the wind resistance and wave resistance are calculated respectively. The propeller open water efficiency is calculated based on the initialized actual speed and actual speed. The total resistance of the ship is calculated based on the ship's still water resistance, wind resistance and wave resistance. Among them, the total resistance of the ship is defined as:

[0147] R T =R Calm +R AW +R Wind

[0148] 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.

[0149] Among them, the hydrostatic resistance of a ship is divided into the following parts:

[0150] R Calm =R F (1+k1)+R APP +R W +R B +R TR +R A

[0151] 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 bulbous bow near water surface. TR为 Square stern immersed part resistance increase, R A is the resistance related to the ship model.

[0152] 1) Friction resistance R F :

[0153]

[0154] In the above formula, C f is the friction coefficient, ΔC f is the roughness compensation coefficient, ρ is the seawater density, V1 is the still water speed, and S is the wetted surface area of ​​the ship.

[0155] 2) Attachment resistance R APP :

[0156]

[0157] In the above formula, S APPis the wetted area of ​​the appendage, the appendage resistance coefficient 1+k2 and the ship friction resistance coefficient C f .

[0158] 3) Wave breaking resistance R W :

[0159]

[0160] 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 wave breaking resistance.

[0161] 4) Increased resistance of bulbous bow near water surface R B :

[0162]

[0163] In the above formula, P R Used to measure the bow effect, F ni is the Froude number when the bow is immersed.

[0164] 5) Square stern immersed part resistance increase R TR :

[0165]

[0166] In the above formula, A T Indicates 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:

[0167]

[0168] Among them, C WP is the design waterplane coefficient, g is the acceleration of gravity, and B is the ship width.

[0169] 6) Ship model related resistance R A

[0170]

[0171] In the above formula, C A is the correlation coefficient.

[0172] Wind resistance is defined as:

[0173]

[0174] In the above formula, R wind is wind resistance, C windRepresents 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.

[0175]

[0176] 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 direction (i.e. wind direction) and the actual speed V direction.

[0177] Wave resistance is defined as:

[0178]

[0179] In the above formula, F r is the Froude number (the ratio of the inertial force in the fluid to the gravity), h represents 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.

[0180] 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 ranging from 0.30 to 1.05, pitch ratios ranging from 0.5 to 1.4, and blades ranging from 2 to 7. The thrust and torque coefficients of the B-series propellers are calculated using the following regression formula:

[0181]

[0182] 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 coefficient of thrust coefficient and torque coefficient is and The power exponents s, t, u, and v of the polynomial regression are obtained by fitting the cavitation water cylinder test data of the Netherlands MARIN using the least squares method.

[0183] 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 based on 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 KQ , calculated according to the following formula:

[0184]

[0185]

[0186] Where, ΔC D is the drag coefficient difference of the cross section. 0.75 is the chord length of the propeller at 75% of the propeller radius. T-B and ΔK Q-B These are the correction values ​​of the thrust coefficient and torque coefficient of the B series propellers, respectively.

[0187] The open water efficiency η0 is:

[0188]

[0189] Hull efficiency η H for:

[0190]

[0191] Among them, t m is the thrust deduction fraction, and w is the propeller wake fraction, which can be calculated using the Taylor method:

[0192] w=0.5C B -0.05

[0193] Among them, C B is the square coefficient.

[0194] Relative rotation efficiency η R for:

[0195]

[0196] 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.

[0197] The speed coefficient J is expressed as:

[0198]

[0199] Where: D p is the propeller diameter, and n is the propeller speed.

[0200] 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 high calculation accuracy requirements in ship speed optimization. In order to ensure high accuracy in propeller propulsion performance calculations, the propeller wake fraction and thrust reduction fraction for specific ships 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:

[0201] t m =0.5C P -0.12

[0202] Among them, C P is the rhombus coefficient.

[0203] The ship's fuel consumption Q is then calculated based on the ship's total resistance, total mileage, hull efficiency, propeller open water efficiency, relative rotation efficiency, and shafting efficiency, using the following formula:

[0204]

[0205] 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.

[0206] Among them, such as Figure 6 As shown in the figure, the total ship fuel consumption of each sub-problem to be optimized is the sum of the ship fuel consumption of each sailing time interval in each sub-problem to be optimized, as shown in the following formula:

[0207]

[0208] Finally, the ship energy efficiency operation index (EEOI) is calculated based on the ship's fuel consumption (Q), total voyage mileage, and total cargo load, using the following formula:

[0209]

[0210] In the above formula, Q is the fuel consumption of the ship (i.e. the total amount of fuel consumed by the ship), C F is the carbon dioxide emission coefficient, m cargo It refers to the cargo (person) load, and D is the total mileage.

[0211] Among them, such as Figure 6 As shown in the following formula, the total ship energy efficiency operation index of each sub-problem to be optimized is the sum of the ship energy efficiency operation indexes of each sailing time interval in each sub-problem to be optimized, as shown in the following formula:

[0212]

[0213] 5. Objective function establishment steps: construct an actual speed value range based on the actual maximum speed and the actual minimum speed in the speed sequence, and construct an actual speed value range based on the actual maximum speed and the actual minimum speed in the speed sequence; under multiple constraints established with the actual speed value range, the actual speed value range and the preset target distance limit as constraints, establish an objective function based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index.

[0214] Specifically, first, according to the actual maximum speed V in the speed sequence max and the actual minimum speed V min Construct the actual speed value range, and construct the first constraint condition based on the actual speed and the actual speed value range, that is, the first constraint condition is expressed as V min ≤V i,j ≤V max ; and according to the actual maximum speed N in the speed sequence max and the actual minimum speed N min Construct the actual speed value interval, and then construct the second constraint condition based on the actual speed and the actual speed value interval, that is, the second constraint condition is expressed as N min ≤N i,j ≤N max Then calculate the average speed V based on the total mileage and total voyage time ship,j , as shown below:

[0215]

[0216] like Figure 7 As shown, according to the initial cumulative navigation distance S from the starting point of the first sub-problem to be optimized to the starting point of the current sub-problem to be optimized 0,j , S 0,j That is, the initial cumulative distance at the beginning of the jth sub-problem to be optimized (that is, the total distance sailed by the first j-1 sub-problems), the cumulative sailing distance S from the starting point of the first sub-problem to be optimized to the end point of the current sub-problem to be optimized f,j , S f,j That is, the cumulative sailing distance (from the starting point to the end of the current sub-problem) at the end of the j-th sub-problem to be optimized, the average speed V ship,j , flight time interval Dt v And the weather credibility factor n a Construct the third constraint, that is, starting from the starting point Port A, the target distance S must be met f,j Constraints:

[0217]

[0218] Finally, under multiple constraints established with the actual speed value range, the actual speed value range and the target distance limit as constraints, the first objective function is established for each of the remaining sub-problems to be optimized except the last sub-problem to be optimized based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index, and under multiple constraints established with the actual speed value range and the actual speed value range as constraints, the second objective function is established for the last sub-problem to be optimized based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index.

[0219] Among them, the first objective function is as follows:

[0220]

[0221] The following constraints are met:

[0222] V min ≤V i,j ≤V max

[0223] N min ≤N i,j ≤N max

[0224] Starting from the starting point Port A, the target distance S must be met. f,j Constraints:

[0225]

[0226] Where V ship,j is the average ship speed, and the formula is as follows:

[0227]

[0228] The second objective function is as follows:

[0229]

[0230] The following constraints are met:

[0231] V min ≤V i,jmax ≤V max

[0232] N min ≤N i,jmax ≤N max

[0233] 6. Optimal solution calculation and dynamic speed optimization steps: Genetic algorithm or particle swarm algorithm is used to calculate the optimal solutions of each first objective function and second objective function respectively, and the optimal speed and optimal rotation speed of each navigation time interval in each sub-problem to be optimized are obtained, thereby minimizing the ship's fuel consumption and the ship's energy efficiency operation index, and realizing dynamic speed optimization of the ship's full mileage.

[0234] Specifically, S1: First, the genetic algorithm or particle swarm algorithm is used to calculate the optimal solution of each first objective function, and the optimal speed and optimal rotation speed of each navigation time interval in each sub-problem to be optimized except the last sub-problem to be optimized are obtained, that is, the recommended speed V is output. * and speed N * :

[0235]

[0236] S2, meet the design speed and rotation speed:

[0237]

[0238] And calculate the starting time point t of the remaining voyage 0,j+1 :

[0239] t 0,j+1 =t 0,j +n b ×Dt v

[0240] and the distance S traveled from the start time 0,j+1 :

[0241]

[0242] S3, and update weather data WSI j+1 :

[0243] WSI k,j+1 =WSI k,j+ 1(v wind , ψ wind , H s ,θ waves )k=1,2,..,n w

[0244] In [t 0,j +(k-1)Dt w ,t 0,j +kDt w ]Interval weather data is represented as:

[0245]

[0246] To the next starting point t0,j+1 .

[0247] S4, such as Figure 8 As shown, for the last sub-problem to be optimized, that is, j=j max , by defining the number of weather intervals does not satisfy the subinterval, then it is necessary to define the last set of weather numbers as n in the last optimization interval w,f , the number of intervals in the last group of speed segments n a,f , respectively:

[0248]

[0249] The weather interval is expressed as:

[0250] WSI k,jmax =WSI k,jmax (v wind , ψ wind , H s ,θ waves )k=1,2,..,n w,f

[0251]

[0252] but:

[0253]

[0254] Sailing max The subproblem can be expressed using i as:

[0255] [t 0,j +(i-1)Dt v ,t 0,j +iDt v ] i=1,2,…n a,f

[0256] The expanded form is:

[0257]

[0258] ①When Dt v >Dt w ,i=1,i≤n a ,i++, the interval is i×Dt v , then the weather interval is:

[0259]

[0260]

[0261] ②When Dt v <Dt w , k++, then the weather interval is:

[0262]

[0263]

[0264] ③When Dt v =Dt w ,k=i=1,2,..,n a,f (n w,f ), the weather interval is:

[0265] WSI i,j =WSI k,j =WSI k,j (v wind ,ψ wind ,H s ,θ waves )

[0266]

[0267] S5. In the last sub-problem to be optimized j max When , the initialization range speed and rotation speed sequence is:

[0268]

[0269] satisfy:

[0270] V min ≤V i,jmax ≤V max N min ≤N i,jmax ≤N max

[0271] S6. Calculate the EEOI of the subinterval i,j and Q i,j :

[0272] EEOI i,j =EEOI i,j (V i,j ,N i,j ,WSI i,j )Q i,j =Q i,j (V i,j ,N i,j ,WSI i,j )

[0273] S7. Calculate n a,f *Dt v Total EEOI for the interval j and Q j :

[0274] f j (EEOI,Q fuel )=k1*EEOI j +k2*Q j

[0275]

[0276] S8. Substitute the genetic algorithm or particle swarm optimization algorithm into the above optimizer to calculate the optimal solution of the second objective function, and obtain the optimal speed and optimal rotation speed for each navigation time interval in the last sub-problem to be optimized, thereby minimizing the ship's fuel consumption and the ship's energy efficiency operation index, and achieving dynamic speed optimization for the entire mileage of the ship. That is, the recommended speed and rotation speed are obtained:

[0277]

[0278] The recommended sailing speed array and rotation speed array are formulated as follows:

[0279]

[0280] It should be noted that the dynamic optimization process is as follows Figure 9 As shown, it is necessary to ensure that the ship arrives at the destination port within the scheduled total time. The result obtained by solving the sub-problem is actually obtained by calculating V at each time instance. ship,j Calculate and judge Dt v , Dt w The relationship between the ship's weather conditions and the weather conditions is determined, and a distance constraint is added in the next optimization step to ensure that the ship completes the total voyage distance. As time passes, the ship gets closer to its final destination, and the optimization problem is continuously solved to ensure that the ship arrives at the port on time and the minimum fuel consumption and EEOI value are obtained.

[0281] The present invention also relates to a ship dynamic speed optimization system considering weather changes. The system corresponds to the above-mentioned ship dynamic speed optimization method considering weather changes and can be understood as a system for implementing the above-mentioned method. The system includes a parameter acquisition and total sailing time calculation module, a sub-problem calculation module to be optimized, a sailing time interval and weather data dynamic matching module, a ship fuel consumption and ship energy efficiency operation index calculation module, an objective function establishment module, and an optimal solution calculation and dynamic speed optimization module, which are connected in sequence. Specifically,

[0282] The parameter acquisition and total sailing time calculation module acquires ship operating parameters and port parameters. The ship operating parameters include actual speed, actual rotation speed, total sailing mileage, ship still water resistance, total cargo load, hull efficiency, relative rotation efficiency and shafting efficiency. The port parameters include initial departure time and final arrival time; the total sailing time is calculated based on the initial departure time and final arrival time.

[0283] The sub-problem calculation module to be optimized sets a navigation time interval and a weather time update interval based on the time dimension, sets a navigation interval multiple for the navigation time interval, and sets a weather credibility multiple for the weather time update interval; calculates a weather credibility window based on the navigation time interval and the weather credibility multiple, and calculates the navigation interval based on the navigation time interval and the navigation interval multiple; calculates the total number of weather time update intervals based on the total navigation time and the set weather time update interval, and calculates the total number of navigation intervals based on the total navigation time, the navigation interval, the navigation interval multiple, and the weather credibility multiple, and then treats each navigation interval as a sub-problem to be optimized, thereby obtaining multiple sub-problems to be optimized;

[0284] The module for dynamically matching flight time intervals with weather data obtains weather data for each weather time update interval and stores the weather data for all weather time update intervals in chronological order as a weather data set. The module then dynamically matches the weather data in the weather data set to each flight time interval of each subproblem to be optimized in a manner that aligns the weather data with the flight time interval based on the size relationship between the flight time interval and the weather time update interval, thereby obtaining a weather array that matches each flight time interval in each subproblem to be optimized.

[0285] The ship fuel consumption and ship energy efficiency operation index calculation module initializes the actual speed and actual speed of each sailing time interval in each sub-problem to be optimized, generates a speed sequence and a speed sequence; calculates the wind resistance and wave resistance based on the initialized actual speed and combined with the matching weather array, and calculates the propeller open water efficiency based on the initialized actual speed and actual speed; calculates the total ship resistance based on the ship's still water resistance, wind resistance and wave resistance, and calculates the ship's fuel consumption based on the total ship resistance, total mileage, propeller open water efficiency, hull efficiency, relative rotation efficiency and shafting efficiency; and then calculates the ship's energy efficiency operation index based on the ship's fuel consumption, total mileage and total cargo load;

[0286] The objective function establishment module constructs an actual speed value interval based on the actual speed maximum value and the actual speed minimum value in the speed sequence, and constructs an actual speed value interval based on the actual speed maximum value and the actual speed minimum value in the speed sequence; under multiple constraints established with the actual speed value interval, the actual speed value interval and the preset target distance limit as constraints, a first objective function is established for each of the remaining sub-problems to be optimized except the last sub-problem to be optimized based on a preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index; and under multiple constraints established with the actual speed value interval and the actual speed value interval as constraints, a second objective function is established for the last sub-problem to be optimized based on the preset weight coefficient, the calculated ship fuel consumption and the ship energy efficiency operation index;

[0287] The optimal solution calculation and dynamic speed optimization module uses a genetic algorithm or a particle swarm algorithm to calculate the optimal solutions of each first objective function and the second objective function respectively, and obtains the optimal speed and optimal rotation speed for each sailing time interval in each sub-problem to be optimized, thereby minimizing the ship's fuel consumption and the ship's energy efficiency operation index, and realizing dynamic speed optimization of the ship's full mileage.

[0288] Preferably, in the module for dynamically matching flight time intervals with weather data, dynamically matching weather data in the weather data set to each flight time interval of each sub-problem to be optimized in a manner that is aligned in time with the flight time interval according to the size relationship between the flight time interval and the weather time update interval specifically includes:

[0289] If the flight time interval is equal to the weather time update interval, the weather data of any weather time update interval in the weather dataset is dynamically matched to the flight time interval that is aligned with the weather time update interval;

[0290] If the flight interval is longer than the weather interval, multiple consecutive weather time update intervals in the weather data set are merged with the same time length as any flight time interval to obtain multiple merged weather time segments, and the weather data of any merged weather time segment is dynamically matched to the flight time interval that is aligned with the weather time segment in time;

[0291] If the navigation interval is smaller than the weather interval, all weather time update intervals in the weather data set are divided equally according to the same time length as any navigation time interval to obtain multiple equally divided weather time segments, and the weather data of any equally divided weather time segment is dynamically matched to the navigation interval that is aligned in time with the weather time segment.

[0292] Preferably, in the parameter acquisition and total sailing time calculation module, the ship operation parameters further include propeller thrust coefficient and torque coefficient to be corrected, windward area, waterline length, wetted area of ​​the ship, and propeller diameter;

[0293] In the ship fuel consumption and ship energy efficiency operation index calculation module, the Reynolds number and roughness are used to correct the propeller thrust coefficient and torque coefficient to be corrected, respectively, to obtain a thrust coefficient correction value and a torque coefficient correction value, respectively; and the actual thrust coefficient and actual torque coefficient of the propeller are calculated based on the thrust coefficient correction value, the torque coefficient correction value, and the propeller thrust coefficient and torque coefficient to be corrected.

[0294] Preferably, in the ship fuel consumption and ship energy efficiency operation index calculation module, the wind resistance and wave resistance are calculated based on the initialized actual speed and in combination with the matched weather array, specifically including:

[0295] The relative wind speed is calculated based on the initialized actual speed and the wind speed and wind direction in the weather array, and the wind resistance is calculated based on the relative wind speed and windward area; the wave resistance is calculated based on the initialized actual speed, the wave height, waterline length and wetted area of ​​the ship in the weather array;

[0296] Calculating the propeller open water efficiency based on the initialized actual ship speed and actual rotational speed specifically includes: calculating the advance coefficient based on the initialized actual ship speed, actual rotational speed and propeller diameter, and calculating the propeller open water efficiency based on the actual thrust coefficient, actual torque coefficient and advance coefficient.

[0297] The present invention provides an objective and scientific method and system for dynamic ship speed optimization that takes weather changes into account. By dynamically matching sailing time intervals with weather data, it can more accurately reflect weather changes during actual sailing, significantly reducing fuel consumption and EEOI values, while ensuring that ships arrive at their destinations on time. This allows fleets to achieve efficient operations and improve overall transportation efficiency. This will bring many benefits, including lower operating costs, increased dry bulk cargo transshipment volume, reduced empty travel and waiting time, and reduced energy consumption and environmental pollution. It can also help fleets achieve efficient operations, maximize profits, and achieve improved transportation efficiency. In addition, the segmented optimization design reduces computational complexity, improves the practicality and real-time performance of the algorithm, and provides an efficient and feasible solution for energy conservation and emission reduction in the shipping industry.

Claims

1. A method for optimizing ship dynamic speed considering weather changes, characterized in that: The following steps are involved: Parameter acquisition and total voyage time calculation steps: obtaining ship operating parameters and port parameters, wherein the ship operating parameters include actual speed, actual rotation speed, total voyage mileage, ship still water resistance, total cargo load, hull efficiency, relative rotation efficiency, and shafting efficiency; and the port parameters include initial departure time and final arrival time; Calculate the total sailing time based on the initial departure time and final arrival time; Calculation steps for the sub-problem to be optimized: set the navigation time interval and weather time update interval based on the time dimension, set the navigation interval multiple for the navigation time interval, and set the weather credibility multiple for the weather time update interval; calculate the weather credibility window based on the navigation time interval and the weather credibility multiple, and calculate the navigation interval based on the navigation time interval and the navigation interval multiple; calculate the total number of weather time update intervals based on the total navigation time and the set weather time update interval, and calculate the total number of navigation intervals based on the total navigation time, navigation interval, navigation interval multiple, and weather credibility multiple, and then treat each navigation interval as a sub-problem to be optimized, resulting in multiple sub-problems to be optimized; Dynamic matching steps between flight time intervals and weather data: obtain weather data for each weather time update interval, and store the weather data for all weather time update intervals in chronological order as a weather dataset; then, based on the size relationship between the flight time intervals and the weather time update intervals, dynamically match the weather data in the weather dataset to each flight time interval of each sub-problem to be optimized in a manner that is aligned in time with the flight time interval, thus obtaining a weather array that matches each flight time interval in each sub-problem to be optimized; Calculation steps for ship fuel consumption and ship energy efficiency operation index: Initialize the actual speed and actual speed of each sailing time interval in each sub-problem to be optimized to generate a speed sequence and a speed sequence; calculate the wind resistance and wave resistance based on the initialized actual speed and the matching weather array, and calculate the propeller open water efficiency based on the initialized actual speed and actual speed; calculate the total ship resistance based on the ship's still water resistance, wind resistance, and wave resistance; calculate the ship's fuel consumption based on the total ship resistance, total sailing mileage, propeller open water efficiency, hull efficiency, relative rotation efficiency, and shafting efficiency; and then calculate the ship's energy efficiency operation index based on the ship's fuel consumption, total sailing mileage, and total cargo load; Objective function establishment steps: construct an actual speed value interval based on the actual maximum speed and the actual minimum speed in the speed sequence, and construct an actual speed value interval based on the actual maximum speed and the actual minimum speed in the speed sequence; Under multiple constraints established with the actual speed value range, the actual speed value range, and the preset target distance limit as constraints, a first objective function is established for each of the remaining sub-problems to be optimized except the last sub-problem to be optimized based on the preset weight coefficient, the calculated ship fuel consumption, and the ship energy efficiency operation index; and under multiple constraints established with the actual speed value range and the actual speed value range as constraints, a second objective function is established for the last sub-problem to be optimized based on the preset weight coefficient, the calculated ship fuel consumption, and the ship energy efficiency operation index; Optimal solution calculation and dynamic speed optimization steps: Genetic algorithm or particle swarm algorithm is used to calculate the optimal solutions of each first objective function and second objective function respectively, and the optimal speed and optimal rotation speed of each navigation time interval in each sub-problem to be optimized are obtained, thereby minimizing the ship's fuel consumption and the ship's energy efficiency operation index, and realizing dynamic speed optimization of the ship's full mileage.

2. The method for optimizing ship dynamic speed considering weather changes according to claim 1, characterized in that: In the step of dynamically matching the flight time interval with the weather data, the weather data in the weather data set is dynamically matched to each flight time interval of each sub-problem to be optimized in a manner that is aligned in time with the flight time interval according to the size relationship between the flight time interval and the weather time update interval. Specifically, the steps include: If the flight time interval is equal to the weather time update interval, the weather data of any weather time update interval in the weather dataset is dynamically matched to the flight time interval that is aligned with the weather time update interval; If the flight interval is longer than the weather interval, multiple consecutive weather time update intervals in the weather data set are merged with the same time length as any flight time interval to obtain multiple merged weather time segments, and the weather data of any merged weather time segment is dynamically matched to the flight time interval that is aligned with the weather time segment in time; If the navigation interval is smaller than the weather interval, all weather time update intervals in the weather data set are divided equally according to the same time length as any navigation time interval to obtain multiple equally divided weather time segments, and the weather data of any equally divided weather time segment is dynamically matched to the navigation interval that is aligned in time with the weather time segment.

3. The method for optimizing ship dynamic speed considering weather changes according to claim 1, characterized in that: In the parameter acquisition and total sailing time calculation steps, the ship operation parameters also include propeller thrust coefficient and torque coefficient to be corrected, windward area, waterline length, ship's wetted area and propeller diameter.

4. The method for optimizing ship dynamic speed considering weather changes according to claim 3, characterized in that: In the calculation steps of the ship fuel consumption and the ship energy efficiency operation index, the Reynolds number and the roughness are used to correct the propeller thrust coefficient and the torque coefficient to be corrected, respectively, to obtain the thrust coefficient correction value and the 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.

5. The method for optimizing ship dynamic speed considering weather changes according to claim 4, characterized in that: In the ship fuel consumption and ship energy efficiency operation index calculation step, the wind resistance and wave resistance are calculated based on the initialized actual speed and in combination with the matched weather array, specifically including: The relative wind speed is calculated based on the initialized actual speed and the wind speed and wind direction in the weather array, and the wind resistance is calculated based on the relative wind speed and windward area; the wave resistance is calculated based on the initialized actual speed, the wave height, waterline length and wetted area of ​​the ship in the weather array; Calculating the propeller open water efficiency based on the initialized actual ship speed and actual rotational speed specifically includes: calculating the advance coefficient based on the initialized actual ship speed, actual rotational speed and propeller diameter, and calculating the propeller open water efficiency based on the actual thrust coefficient, actual torque coefficient and advance coefficient.

6. The method for optimizing ship dynamic speed considering weather changes according to any one of claims 1 to 5, characterized in that: In the objective function establishment step, the average speed is also calculated based on the total mileage and the total navigation time. The multiple constraints include a first constraint established with the actual speed value range as a constraint, a second constraint established with the actual speed value range as a constraint, and a third constraint established with the preset target distance limit as a constraint; the first constraint is constructed based on the actual speed and the actual speed value range, the second constraint is constructed based on the actual speed and the actual speed value range, and the third constraint is constructed based on the initial cumulative navigation distance from the starting point of the first sub-problem to be optimized to the starting point of the current sub-problem to be optimized, the cumulative navigation distance from the starting point of the first sub-problem to be optimized to the end point of the current sub-problem to be optimized, the average speed, the navigation time interval and the weather credibility multiple.

7. A ship dynamic speed optimization system considering weather changes, characterized in that: It includes the sequentially connected parameter acquisition and total sailing time calculation module, the sub-problem calculation module to be optimized, the sailing time interval and weather data dynamic matching module, the ship fuel consumption and ship energy efficiency operation index calculation module, the objective function establishment module, and the optimal solution calculation and dynamic speed optimization module. The parameter acquisition and total sailing time calculation module acquires ship operating parameters and port parameters. The ship operating parameters include actual speed, actual rotation speed, total sailing mileage, ship still water resistance, total cargo load, hull efficiency, relative rotation efficiency and shafting efficiency. The port parameters include initial departure time and final arrival time. Calculate the total sailing time based on the initial departure time and final arrival time; The sub-problem calculation module to be optimized sets a navigation time interval and a weather time update interval based on the time dimension, sets a navigation interval multiple for the navigation time interval, and sets a weather credibility multiple for the weather time update interval; calculates a weather credibility window based on the navigation time interval and the weather credibility multiple, and calculates the navigation interval based on the navigation time interval and the navigation interval multiple; calculates the total number of weather time update intervals based on the total navigation time and the set weather time update interval, and calculates the total number of navigation intervals based on the total navigation time, the navigation interval, the navigation interval multiple, and the weather credibility multiple, and then treats each navigation interval as a sub-problem to be optimized, thereby obtaining multiple sub-problems to be optimized; The module for dynamically matching flight time intervals with weather data obtains weather data for each weather time update interval and stores the weather data for all weather time update intervals in chronological order as a weather data set. The module then dynamically matches the weather data in the weather data set to each flight time interval of each subproblem to be optimized in a manner that aligns the weather data with the flight time interval based on the size relationship between the flight time interval and the weather time update interval, thereby obtaining a weather array that matches each flight time interval in each subproblem to be optimized. The ship fuel consumption and ship energy efficiency operation index calculation module initializes the actual speed and actual speed of each sailing time interval in each sub-problem to be optimized, generates a speed sequence and a speed sequence; calculates the wind resistance and wave resistance based on the initialized actual speed and combined with the matching weather array, and calculates the propeller open water efficiency based on the initialized actual speed and actual speed; calculates the total ship resistance based on the ship's still water resistance, wind resistance and wave resistance, and calculates the ship's fuel consumption based on the total ship resistance, total mileage, propeller open water efficiency, hull efficiency, relative rotation efficiency and shafting efficiency; and then calculates the ship's energy efficiency operation index based on the ship's fuel consumption, total mileage and total cargo load; The objective function establishment module constructs an actual speed value interval according to the actual maximum speed and the actual minimum speed in the speed sequence, and constructs an actual speed value interval according to the actual maximum speed and the actual minimum speed in the speed sequence; Under multiple constraints established with the actual speed value range, the actual speed value range, and the preset target distance limit as constraints, a first objective function is established for each of the remaining sub-problems to be optimized except the last sub-problem to be optimized based on the preset weight coefficient, the calculated ship fuel consumption, and the ship energy efficiency operation index; and under multiple constraints established with the actual speed value range and the actual speed value range as constraints, a second objective function is established for the last sub-problem to be optimized based on the preset weight coefficient, the calculated ship fuel consumption, and the ship energy efficiency operation index; The optimal solution calculation and dynamic speed optimization module uses a genetic algorithm or a particle swarm algorithm to calculate the optimal solutions of each first objective function and the second objective function respectively, and obtains the optimal speed and optimal rotation speed for each sailing time interval in each sub-problem to be optimized, thereby minimizing the ship's fuel consumption and the ship's energy efficiency operation index, and realizing dynamic speed optimization of the ship's full mileage.

8. The ship dynamic speed optimization system considering weather changes according to claim 7 is characterized in that: In the module for dynamically matching flight time intervals with weather data, the weather data in the weather data set is dynamically matched to each flight time interval of each sub-problem to be optimized in a manner that is aligned with the flight time interval in time, based on the size relationship between the flight time interval and the weather time update interval. Specifically, the following steps are performed: If the flight time interval is equal to the weather time update interval, the weather data of any weather time update interval in the weather dataset is dynamically matched to the flight time interval that is aligned with the weather time update interval; If the flight interval is longer than the weather interval, multiple consecutive weather time update intervals in the weather data set are merged with the same time length as any flight time interval to obtain multiple merged weather time segments, and the weather data of any merged weather time segment is dynamically matched to the flight time interval that is aligned with the weather time segment in time; If the navigation interval is smaller than the weather interval, all weather time update intervals in the weather data set are divided equally according to the same time length as any navigation time interval to obtain multiple equally divided weather time segments, and the weather data of any equally divided weather time segment is dynamically matched to the navigation interval that is aligned in time with the weather time segment.

9. The ship dynamic speed optimization system considering weather changes according to claim 7, characterized in that: In the parameter acquisition and total sailing time calculation module, the ship operation parameters also include the propeller thrust coefficient and torque coefficient to be corrected, the windward area, the waterline length, the wetted area of ​​the ship, and the propeller diameter; In the ship fuel consumption and ship energy efficiency operation index calculation module, the Reynolds number and roughness are used to correct the propeller thrust coefficient and torque coefficient to be corrected, respectively, to obtain a thrust coefficient correction value and a torque coefficient correction value, respectively; and the actual thrust coefficient and actual torque coefficient of the propeller are calculated based on the thrust coefficient correction value, the torque coefficient correction value, and the propeller thrust coefficient and torque coefficient to be corrected.

10. The ship dynamic speed optimization system considering weather changes according to claim 9, characterized in that: In the ship fuel consumption and ship energy efficiency operation index calculation module, the wind resistance and wave resistance are calculated based on the initialized actual speed and the matched weather array, specifically including: The relative wind speed is calculated based on the initialized actual speed and the wind speed and wind direction in the weather array, and the wind resistance is calculated based on the relative wind speed and windward area; the wave resistance is calculated based on the initialized actual speed, the wave height, waterline length and wetted area of ​​the ship in the weather array; Calculating the propeller open water efficiency based on the initialized actual ship speed and actual rotational speed specifically includes: calculating the advance coefficient based on the initialized actual ship speed, actual rotational speed and propeller diameter, and calculating the propeller open water efficiency based on the actual thrust coefficient, actual torque coefficient and advance coefficient.

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