A modular ship dynamics model building method

Abstract

This invention is applicable to the fields of ship dynamics modeling and intelligent ships, and provides a modular method for establishing ship dynamics models, including: S1, establishing a three-degree-of-freedom motion model of the ship; S2, selecting a single or dual-propeller model according to the number of propellers, and calculating the propeller sway force; S3, selecting an integrated azimuth or rudder-propeller separated model according to the type of the ship's rudder system, and calculating the rudder sway force, roll force, and yaw moment; S4, substituting the results of S2 and S3 into the control motion equations of S1 to complete the establishment of the ship dynamics model; In this invention, the modular architecture solves the problem of ship type adaptation; physical measurement + empirical formulas reduce the difficulty of parameter identification; and refined models improve prediction accuracy.

Description

Technical Field

[0001] This invention belongs to the field of ship dynamics modeling and intelligent ships, and particularly relates to a method for establishing a modular ship dynamics model. Background Technology

[0002] The diversity of ship types makes modeling and adaptation difficult: Inland waterway vessels include cargo ships (up to 110m in length), passenger ships (about 85m in length), and engineering vessels (about 60m in length), with significant differences in structural layout, power configuration (diesel / electric / hybrid power), and rudder system (integrated full-rotation / rudder-propeller separation). Traditional single dynamic models require reconstructing equations for each ship type, and simplified models ignore key factors such as propeller interference and rudder surface water flow changes, which cannot cover multiple ship types, resulting in low adaptation efficiency and difficulty in supporting motion controller design and trajectory estimation for different ship types.

[0003] Model parameter identification is costly and time-consuming: ship dynamics models require additional mass on the hull ( ), Propulsion system wake fraction ( ), Rudder system rudder force amplification coefficient ( Parameters such as these require traditional methods to obtain through towing tank experiments on a 1:20 scale model. This results in high costs per experiment, a cycle of up to one month, and the experimental results need to be recalculated to be adapted to the actual ship, leading to low efficiency in parameter acquisition.

[0004] Traditional models cannot meet the accuracy requirements of operating conditions: existing dual-propeller models do not consider the water flow interference between the left and right propellers, resulting in a yaw moment prediction error >8%; rudder-propeller separated models ignore the effective inflow angle of the rudder ( The dynamic changes and the error in the rudder torque response time under the turning condition are >0.5s; the torque error of the full-turn engineering vessel is >8% when operating in complex waters, which cannot meet the requirements of high maneuverability of passenger ships (turning radius error must be <5%) and precise control of engineering vessels (torque error must be <4%). Therefore, a modular method for establishing ship dynamics models is needed to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for establishing a modular ship dynamics model to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for establishing a modular ship dynamics model includes the following steps: S1. Establish a three-degree-of-freedom motion model for the ship, based on the Earth-fixed coordinate system ( - - The origin is the starting point of the maneuvering motion) and the ship coordinate system ( - - (with the origin set at the center of the hull), construct the equations of maneuvering motion; S2. Select either the single or dual-propeller model based on the number of ship propellers, and calculate the propeller sway force. (Single thruster) or (Dual thrusters); S3. Select an integrated azimuth or rudder-propeller separated model based on the type of ship's rudder system, and calculate the rudder's pitching force. sway force and yaw moment ; S4, the result of S2 and S3 , and Substitute the maneuvering equations into S1 to complete the establishment of the ship dynamics model.

[0007] A further technical solution, in S1, is that the equation of motion for manipulation is: ; ; ; In the formula, , and Forces and moments in the directions of sway, roll, and yaw, respectively, with subscripts. , and These refer to the hull, rudder, and propeller, respectively. It is the quality of the ship. ( (for the captain) This is the longitudinal distance between the ship's centers of gravity. , and These are the added mass of the sway and the added moment of inertia of the yaw, respectively. Based on the Earth-fixed coordinate system The axis is the initial heading, and the origin is the starting point of maneuvering) and the ship's coordinate system ( The axis points longitudinally towards the bow along the hull. (The axis points laterally to the starboard side). The three-degree-of-freedom maneuvering motion equations are derived using Newton's second law, clarifying the force and torque coupling relationship between the hull, propeller, and rudder. Sub-models are selected based on the number of propellers and the type of rudder system, and the outputs are integrated and substituted into the equations to complete the modeling. Enhanced effects: Breaking the limitation of "one ship, one model", sub-models can be replaced to adapt to different ship types without reconstructing equations, improving modeling efficiency by more than 40% and solving the problem of difficult adaptation of traditional models.

[0008] A further technical solution, in S2, is the single-propeller model. The calculation formula is: ; In the formula, =-0.27 (propeller thrust deduction factor). For the density of water, For propeller speed and diameter, - The thrust coefficient is obtained by fitting a quadratic polynomial to the characteristics of open water. Let x be the velocity in the ship's coordinate system. ( For ship block coefficient, single propeller ), ( for (Directional velocity, i.e., drift angle). The dimensionless distance from the propeller to the longitudinal centerline of the hull. Yaw angular velocity; This formula corrects for the propeller's geometric inflow angle and relates it to ship motion parameters ( , , ) and thruster physical parameters ( , ),accomplish Precise calculations.

[0009] For single-propeller vessels (such as cargo ships), the propeller geometric inflow angle is introduced ( Correction of the associated flow fraction The thrust coefficient was fitted using a quadratic polynomial. - Combined with physical measurements , Calculated with empirical formulas and It obtains oscillation force; Without relying on towing tank experiments, the cost of parameter acquisition is reduced by 60%, and the thrust prediction error of single-propeller cargo ships is reduced from the traditional 8% to 3.8% (RMSE=1.2kN), solving the problems of high cost and insufficient accuracy of parameter identification.

[0010] A further technical solution, in S2, involves the left and right thruster sway forces of the dual-propeller model. The calculation formula is: ; In the formula, the subscript , Refers to the left and right thrusters. This is the deduction factor for the left and right thrust. The rotational speed and diameter of the left and right propellers. The diameter of the left and right propellers. This is the dimensionless distance from the position of the port and starboard propellers to the longitudinal centerline of the hull. This represents the offset of the propeller relative to the longitudinal centerline of the hull. This represents the effective wake fraction at the positions of the left and right propellers when the ship is moving in a straight line. = (Dual thrusters) When the propeller models are the same and the speed difference is ≤5%, = , = , = This formula introduces an inflow velocity correction term. Quantify the influence of water flow interference on the left and right thrusters, and correlate the thruster installation position parameters ( ) and ship motion parameters to achieve , Collaborative computing; For ships with two propellers (such as passenger ships), considering the symmetrical installation characteristics of the left and right propellers, an inflow velocity correction term is introduced. To quantify the impact of water flow interference, simplified parameter calculations were performed when the propeller models were identical and the speed difference was ≤5%, resulting in the following: and ; The accuracy of yaw moment prediction is improved by 12%-15% compared with traditional models, and the yaw moment error of dual-propeller passenger ships is reduced to This meets the high maneuverability requirements of passenger ships.

[0011] Further technical solutions, in S3, include single and dual thruster sub-models in the integrated full-rotation system model: With a single thruster, , ; With dual thrusters, , ; In the formula, , , This is the thruster steering angle (counterclockwise is positive). The offset of the two thrusters relative to the longitudinal centerline ( ), The distance from the propeller to the longitudinal centerline of the hull; this model uses the propeller steering angle ( , , The thrust of the thruster obtained from S2 is related to ( , , ) and rudder force and torque, combined with propeller installation parameters ( , This enables dynamic calculation of forces and moments in an integrated system. By the thruster steering angle ( , , Associated thruster thrust ( , , In the dual-thrust scenario, the offset y is introduced in relation to the rudder force / torque. p Correcting yaw moment to reflect thrust vector control characteristics in real time; The lateral force error of the fully azimuth-rotating engineering vessel is as low as 2.7% (RMSE=0.8kN), and the steering response delay is <0.5s, solving the problem of large torque error in complex waters.

[0012] A further technical solution in S3 is that the propeller-decoupled system model includes single and dual propeller sub-models: With a single thruster, , ; With dual thrusters, , ; In the formula, =-0.629 ²+0.605 +0.129 (steering resistance deduction factor). =3.349 ²-3.293 +1.059 (rudder force amplification factor); For the longitudinal coordinate of the rudder, and These are the lateral coordinates of the left and right rudders, respectively; this model is achieved through... and (related) ) and rudder installation parameters ( , , ), combined with the normal force of the rudder This involves coupling the rudder system with the parameters of the hull and propulsion system to achieve force and torque calculations for the separate system. Calculation based on empirical formulas and (related) ), combined with the ship's rudder physical parameters ( , ) and installation parameters ( , , ), through the normal force of the rudder Calculate the rudder force / torque to avoid neglecting the dynamics of the rudder flow; The rudder torque response time error of the rudder propeller-separated cargo ship is reduced to 0.3s, and the maximum error ratio is ≤5.1%, which meets the requirements of cargo ships sailing under varying loads.

[0013] Further technical solutions, rudder normal force and The calculation formula is: , Corresponding to the normal forces of the left and right rudders; In the formula, This represents the cross-sectional area of ​​the movable part of the rudder. (Water flow velocity at the rudder, and (Representing the longitudinal and lateral inflow velocities of the rudder, respectively). (Rudder lift gradient coefficient, (for the rudder aspect ratio). (Effective inflow angle of the rudder), with dual thrusters This formula uses rudder physical parameters ( , ), water flow parameters ( ) and ship motion parameters ( , Correcting the effective inflow angle of the rudder Quantifying the effects of water flow changes The influence of this provides accurate input for the calculation of rudder force and torque in S3; Introducing rudder aspect ratio Corrected rudder lift gradient coefficient Through the water flow velocity at the rudder (related) and Corrected rudder effective inflow angle With dual thrusters, the influence of lateral inflow velocity is further corrected to obtain precise... ; The accuracy of rudder force calculation is improved by 10%, which can adapt to the modeling needs of variable load and variable working conditions and solve the problem of traditional models ignoring water flow changes.

[0014] Further technical solutions, in S1, and Calculated using empirical formulas: , ; In the formula, The average draft of the ship. For the width of the boat, For the ship's length; this empirical formula is directly related to the ship's basic parameters ( , , , , With added mass and moment of inertia, key coefficients for the maneuvering equations of S1 can be provided without experimentation, enabling rapid quantification of hull dynamics. Based on ship basic parameters ( , , , , ), calculated directly using empirical formulas , and It can provide key coefficients for three-degree-of-freedom equations without the need for experiments; The parameter calculation cycle has been shortened from 1 month to 1 hour, and the error between the calculated value and the experimental value is less than 5%, which greatly reduces the parameter identification cycle and cost.

[0015] Further technical solutions include model integration and accuracy control steps: based on the three-degree-of-freedom motion equations of S1, receiving the output of S2... , and S3 output , and The output of claim 8 , and and the results of calculation Substitute the values ​​into the equations to complete the model assembly; the model error must meet the following requirements: thrust RMSE ≤ 1.2kN, yaw moment Lateral force RMSE ≤ 0.8kN, rudder torque response time error ≤ 0.3s, maximum error percentage ≤ 5.1%; this step forms a complete modeling closed loop by connecting the outputs of each sub-model with the core equation, while limiting the error threshold to ensure that the model accuracy meets the needs of practical applications. This forms a complete modeling closed loop, which can be integrated into intelligent ship control systems and supports real-time model correction (such as GPS speed measurement calibration). It meets the standards for motion controller design (error <10%) and trajectory estimation (error <8%).

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention solves the ship type adaptation problem with a modular architecture: by splitting the ship into a "three-degree-of-freedom hull model + propeller model + rudder model", the sub-model can be flexibly selected according to the number of propellers (single and dual) and the type of rudder system (integrated and separate). The same method can adapt to 110m single-propeller cargo ships, 85m dual-propeller passenger ships, and 60m azimuth engineering ships without repeated modeling. The efficiency of multi-ship type adaptation is improved by 40%, solving the adaptation problem of "one ship, one model" in traditional models. This invention reduces the difficulty of parameter identification through physical measurement and empirical formulas: thruster , rudder and These parameters can be directly measured physically. , , Difficult-to-measure parameters are obtained through empirical formulas (such as...) =0.5 The calculation of -0.05) eliminates the need for dragging a water tank experiment; the cost of parameter acquisition is reduced by 60%, and the cycle is shortened from 1 month to 1 hour, solving the problems of high cost and long cycle of traditional parameter identification; This invention improves prediction accuracy through a refined model: the single-thruster model considers inflow angle correction, the dual-thruster model considers water flow interference, the rudder model considers the dynamic changes in the effective inflow angle, and the ship system considers multi-parameter coupling, with an overall model error ≤5.1%; among which, the yaw moment accuracy of dual-thrusters is improved by 12%-15%, and the moment error of engineering vessels in complex waters is <4%, meeting the working conditions requirements of high maneuverability of passenger ships and precise control of engineering vessels, and solving the problem of insufficient accuracy of traditional models.

[0017] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process of the present invention; Figure 2 This is a diagram showing the coordinate system and parameter definition for the three-degree-of-freedom motion of a ship according to the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0021] Example 1: Modeling of a cargo ship with a single propeller and separate rudder propeller system; like Figures 1-2As shown, this embodiment of the invention provides a method for establishing a modular ship dynamics model. Ship parameters: length L = 110m, beam B = 16m, average draft d = 5m, displacement 8000t (ship mass m = 8 × 10⁻⁶). 6 kg), block coefficient =0.72 (compliant with single thruster) (Requirement ∈ [0.56, 0.87]), the rudder system is a single-propeller, separate rudder-propeller type, with a propeller diameter of... =3.2m, propeller speed =800r / min, cross-sectional area of ​​movable part of the rudder =8m², rudder aspect ratio Λ=1.2.

[0022] Sub-model and parameter calculation: Thruster model: A single thruster model is selected. =-0.27, =0.5×0.72-0.05=0.31, thrust coefficient =0.2, k1=-0.1, =0.02, substituting into the formula of claim 3, we get ; Ship rudder model: A separate rudder and propeller model is selected. =-0.629×0.72²+0.605×0.72+0.129≈0.35, =3.349×0.72²-3.293×0.72+1.059≈0.82, =6.13×1.2 / (1.2+2.25)≈2.15, combining with the formula in claim 7, we get Substituting this into the formula of claim 6, we get... , and ; Ship system number: Substitute into the formula of claim 8, =0.05×8×10 6 =4×10 5 kg, =8×10 6 ×(0.882-0.54×0.72×(1-1.6×5 / 16)-0.156×(1-0.673×0.72)×110 / 16)≈4.08×10 6 kg, ≈1.2×10 11 , =8×10 6 ×(0.25×110) 2 =6.05×109 ; Model integration and testing: , , and Substituting the ship's system parameters into the three-degree-of-freedom equations of motion, tests were conducted on still water straight-line navigation and turning (rudder angle). =10°-30°), variable load (full load / no load) working conditions.

[0023] In this embodiment, the comparison between the thrust predicted by the model and the actual ship measurement data shows that the thrust error under full load condition is only 2.1% (RMSE=0.9kN), and the error under no-load condition is 3.5% (RMSE=1.2kN), both lower than the 8% error threshold of the traditional model; the rudder torque response time error is 0.2s, with a maximum error ratio of 4.5%, meeting the actual requirements of cargo ship variable load navigation (error must be <5%) and port turning (response time error must be <0.3s); this model can be directly used for the debugging of cargo ship heading control without repeated actual ship trials, reducing the cost of actual ship trials by 30%.

[0024] Example 2: Modeling of a passenger ship with dual thrusters and an integrated azimuth system; The difference between this embodiment and Embodiment 1 is as follows: Ship parameters: Length L=85m, Beam B=18m, Average draft d=3.5m, Displacement 5000t (Ship mass m=5×10 6 kg), block coefficient =0.51 (compliant with dual thrusters) (Requirement ∈ [0.42, 0.62]), the rudder system is a dual-thrust integrated full-rotation system, with left and right thruster diameters... = =2.8m, rotational speed = =1000r / min, thruster offset relative to longitudinal centerline = =3.5m, distance from the propeller to the longitudinal centerline of the hull =8m, maximum steering angle ±90°.

[0025] Sub-model and parameter calculation: Thruster model: A dual-thruster model is selected. = =-0.27, = =0.5×0.51-0.05=0.205, substituting into the formula of claim 4, we get ; Ship rudder model: An integrated full-rotation model is selected, based on the steering angle. , (Test range 0°-90°), substituting into the formula of claim 5, we get... , and ; Ship system number: Substitute into the formula of claim 8, =0.05×5×10 6 =2.5×10 5 kg, =5×10 6 ×(0.882-0.54×0.51×(1-1.6×3.5 / 18)-0.156×(1-0.673×0.51)×85 / 18)≈2.2×10 6 kg, ≈8.5×10 10 ; Model integration and testing: , , and Substituting the system number into the three-degree-of-freedom motion equation, the tests were conducted under the following conditions: straight-line navigation, turning (δ=0°-90°), and berthing (ship speed u=2m / s).

[0026] In this embodiment, at a steering angle of 30°, the model-predicted yaw moment has an error of 3.8% compared to the actual ship data. At a steering angle of 90° (full azimuth operation), the yaw moment error is 4.2%. Compared to the traditional model with an error of >8%, the error is significantly reduced; the turning radius prediction error is <4.5%, and the sway force response delay is <0.4s, which fully meets the design requirements of passenger ships for high maneuverability (turning radius error must be <5%) and safe berthing (response delay must be <0.5s); this model can directly support the development and debugging of passenger ship automatic berthing systems, improving berthing efficiency and safety.

[0027] Example 3: Modeling of a Dual-Thruster + Separate Rudder-Propeller System Engineering Vessel The difference between this embodiment and Embodiment 2 is as follows: Ship parameters: Length L=60m, Beam B=20m, Average draft d=4m, Displacement 3000t (Ship mass m=3×10 6 kg), block coefficient =0.58, the rudder system is a dual-propeller, separate rudder and propeller type, the diameter of the left and right propellers is... = =2.5m, rotation speed = =900r / min, thruster offset = =4m, cross-sectional area of ​​port and starboard rudders = =6m 2 rudder aspect ratio =1.2, longitudinal coordinate of the rudder || ||=5m, horizontal coordinate =-3m、 =3m.

[0028] Sub-model and parameter calculation: Thruster model: Using a dual-thruster model, substituting into the formula of claim 4 yields... , ; Ship rudder model: A separate rudder and propeller model is selected. =-22.2×(0.58×20 / 60)²+0.02×(0.58×20 / 60)+0.68≈0.65, combining with the formula in claim 7, we get and Substituting this into the formula of claim 6, we get... , and ; Ship system number: Substitute into the formula of claim 8, =3×10 6 ×(0.882-0.54×0.58×(1-1.6×4 / 20)-0.156×(1-0.673×0.58)×60 / 20)≈0.42×3×10 6 kg; Model integration and testing: , , and The ship system parameters were substituted into the three-degree-of-freedom motion equations to test complex water conditions such as bridge turning and near-shore operations.

[0029] In this embodiment, the torque prediction error in complex waters (such as turbulent areas near bridges) is <4%, significantly better than the >8% error of traditional models; the lateral force response time error is 0.3s, meeting the stringent requirements for precise positioning of engineering vessels (torque error <5%) and turning in bridge areas (response time error <0.4s); the application of this model can reduce the collision risk of engineering vessels in narrow waters by 25%, providing strong support for operational safety in complex scenarios such as bridge areas and near shore. Working principle and usage process of this invention: A four-step closed-loop process—parameter acquisition, sub-model calculation, model integration, and accuracy verification—is used to accurately establish a modular ship dynamics model. The specific process is as follows: Determining Ship Parameters and Modeling Requirements: First, collect the basic parameters of the target ship, including ship size parameters (length L, beam B, average draft d), mass parameters (ship mass m, displacement), and power configuration parameters (number of propellers, propeller type, etc.). , ), Rudder system parameters (rudder system type, rudder) Λ, Installation location , ), hull characteristic parameters (block coefficient) Longitudinal center of gravity distance At the same time, the modeling requirements are clearly defined, such as cargo ships needing to be adaptable to variable load conditions, passenger ships needing to meet high maneuverability requirements, and engineering vessels needing to be adaptable to complex waters, providing a basis for the selection of subsequent sub-models.

[0030] Sub-model selection and parameter co-computation: Thruster sub-model calculation: Select single / dual thruster model based on the number of thrusters (claims 3 / 4); physical measurement , , , Parameters, through empirical formulas ( =0.5 -0.05、 =-0.27) Calculate the difficult-to-measure parameters; combine the ship's real-time motion parameters (u, v, r) and substitute them into the corresponding formulas to calculate. (Single thruster) or (Dual thrusters); During the calculation process, if there are dual thrusters and the speed difference is ≤5%, parameter simplification is automatically enabled (t). p l=t p (e.g., r) to reduce computational load.

[0031] Ship rudder model calculation: Select an integrated azimuth / rudder-propeller separate model based on the rudder system type (claims 5 / 6); physical measurement , , , , , , Parameters, through empirical formulas ( , Related )calculate , Based on ship motion parameters ( Substituting into the formula of claim 7, the calculation is performed. , , Substituting this into the rudder model formula, we get... , , Automatic correction in dual-thruster scenarios To quantify the impact of lateral water flow.

[0032] Ship system number calculation: This involves calculating the ship's basic parameters ( d Substituting m into the empirical formula of claim 8, calculate , and ;pass =m(0.25 )² Calculate the hull's moment of inertia; during the calculation, simultaneously receive the output parameters of the propulsion / rudder system to ensure that the hull parameters are synchronized with the power and rudder system parameters (e.g., Simultaneously used for and , calculate).

[0033] Multi-module integration and model building: Using the three-degree-of-freedom maneuvering equations of S1 as the core framework, the output of the thruster sub-model... , , "Thrust force" on the right side of the access equation "Item, the output of the ship's rudder model" , , Access to "rudder force" , "Rudder torque" "Item, calculation of ship system numbers" , , and Substitute the "additional mass / moment of inertia" term on the left side of the equation; simultaneously consider the ship's own forces and moments. , , (Obtained from a ship hydrodynamic database), forming complete dynamic equations and completing model assembly.

[0034] Accuracy Verification and Iterative Optimization: Typical operating conditions (straight-line navigation in calm water, turning, variable speed / variable load) are selected for actual ship testing, and data such as thrust, torque, and response time are collected. The model predictions are compared with the actual ship data, and the RMSE (thrust / yaw moment / lateral force), response time error, and maximum error percentage are calculated. If the error is ≤5.1% (meeting the threshold of claim 9), the modeling is complete. If the error exceeds the standard, GPS speed measurement is used for calibration. (Correct the wake fraction), perform actual ship turning test calibration δ (correct rudder angle deviation), re-substitute into the sub-model calculation, iterate and optimize until the error meets the standard, and ensure that the model accuracy meets the actual application requirements.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for establishing a modular ship dynamics model, characterized in that, Includes the following steps: S1. Establish a three-degree-of-freedom motion model for the ship, based on the Earth-fixed coordinate system ( - - The origin is the starting point of the maneuvering motion) and the ship coordinate system ( - - (with the origin set at the center of the hull), construct the equations of maneuvering motion; S2. Select either the single or dual-propeller model based on the number of ship propellers, and calculate the propeller sway force. (Single thruster) or (Dual thrusters); S3. Select an integrated azimuth or rudder-propeller separated model based on the type of ship's rudder system, and calculate the rudder's pitching force. sway force and yaw moment ; S4, the result of S2 and S3 , and Substitute the maneuvering equations into S1 to complete the establishment of the ship dynamics model.

2. The modular ship dynamics model establishment method according to claim 1, characterized in that, In S1, the equation of motion for manipulation is: ； ； ； In the formula, , and Forces and moments in the directions of sway, roll, and yaw, respectively, with subscripts. , and These refer to the hull, rudder, and propeller, respectively. It is the quality of the ship. ( (for the captain) This is the longitudinal distance between the ship's centers of gravity. , and These are the added mass of the sway, the added mass of the yaw, and the added moment of inertia of the yaw.

3. The modular ship dynamics model establishment method according to claim 1, characterized in that, In S2, the single-thruster propeller model The calculation formula is: ； In the formula, =-0.27 (propeller thrust deduction factor). For the density of water, For propeller speed and diameter, and The thrust coefficient is obtained by fitting a quadratic polynomial to the characteristics of open water. Let x be the velocity in the ship's coordinate system. ( For ship block coefficient, single propeller ), ( for (Directional velocity, i.e., drift angle). The dimensionless distance from the propeller to the longitudinal centerline of the hull. Yaw angular velocity; This formula corrects for the propeller's geometric inflow angle and relates it to ship motion parameters ( , , ) and thruster physical parameters ( , ),accomplish Precise calculations.

4. The method for establishing a modular ship dynamics model according to claim 1, characterized in that, In S2, the sway force of the left and right thrusters of the dual-thruster propeller model. The calculation formula is: ; In the formula, the subscript , Refers to the left and right thrusters. This is the deduction factor for the left and right thrust. The rotational speed and diameter of the left and right propellers. The diameter of the left and right propellers. This is the dimensionless distance from the position of the port and starboard propellers to the longitudinal centerline of the hull. This represents the offset of the propeller relative to the longitudinal centerline of the hull. This represents the effective wake fraction at the positions of the left and right propellers when the ship is moving in a straight line. = (Dual thrusters) When the propeller models are the same and the speed difference is ≤5%, = , = , = This formula introduces an inflow velocity correction term ( Quantify the influence of water flow interference on the left and right thrusters, and correlate the thruster installation position parameters ( ) and ship motion parameters to achieve , Collaborative computing.

5. The modular ship dynamics model establishment method according to claim 1, characterized in that, In S3, the integrated full-rotation system model includes single and dual-thrust sub-models: With a single thruster, , ; With dual thrusters, , ; In the formula, , , This is the thruster steering angle (counterclockwise is positive). The offset of the two thrusters relative to the longitudinal centerline ( ), The distance from the propeller to the longitudinal centerline of the hull; this model uses the propeller steering angle ( , , The thrust of the thruster obtained from S2 is related to ( , , ) and rudder force and torque, combined with propeller installation parameters ( , This enables dynamic calculation of forces and torques in an integrated system.

6. The method for establishing a modular ship dynamics model according to claim 1, characterized in that, In S3, the propeller-decoupled system model includes single and dual propeller sub-models: With a single thruster, , ; With dual thrusters, , ; In the formula, =-0.629 ²+0.605 +0.129 (steering resistance deduction factor). =3.349 ²-3.293 +1.059 (rudder force amplification factor); For the longitudinal coordinate of the rudder, and These are the lateral coordinates of the left and right rudders, respectively; this model is achieved through... and (related) ) and rudder installation parameters ( , , ), combined with the normal force of the rudder The rudder system is coupled with the parameters of the hull and propulsion system to realize the calculation of forces and torques of the separate system.

7. The method for establishing a modular ship dynamics model according to claim 6, characterized in that, Rudder normal force and The calculation formula is: , Corresponding to the normal forces of the left and right rudders; In the formula, This represents the cross-sectional area of ​​the movable part of the rudder. (Water flow velocity at the rudder, and (Representing the longitudinal and lateral inflow velocities of the rudder, respectively). (Rudder lift gradient coefficient, (for the rudder aspect ratio). (Effective inflow angle of the rudder), with dual thrusters This formula uses rudder physical parameters ( , ), water flow parameters ( ) and ship motion parameters ( , Correcting the effective inflow angle of the rudder Quantifying the effects of water flow changes The influence of this provides accurate input for the calculation of rudder force and torque in S3.

8. The method for establishing a modular ship dynamics model according to claim 1, characterized in that, In S1, and Calculated using empirical formulas: , ; In the formula, The average draft of the ship. For the width of the boat, For the ship's length; this empirical formula is directly related to the ship's basic parameters ( , , , , With added mass and moment of inertia, key coefficients for the maneuvering equations of S1 can be provided without experimentation, enabling rapid quantification of hull dynamics.

9. The method for establishing a modular ship dynamics model according to claim 1, characterized in that, It also includes model integration and accuracy control steps: based on the three-degree-of-freedom motion equations of S1, receiving the output of S2. , and S3 output , and The output of claim 8 , and and the results of calculation Substitute the values ​​into the equations to complete the model assembly; the model error must meet the following requirements: thrust RMSE ≤ 1.2kN, yaw moment The lateral force RMSE is ≤0.8kN, the rudder torque response time error is ≤0.3s, and the maximum error percentage is ≤5.1%. This step forms a complete modeling closed loop by connecting the outputs of each sub-model with the core equation, while limiting the error threshold to ensure that the model accuracy meets the requirements of practical applications.

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