Research On Simulation Platform Of Intelligent Ship Driven By Hydrodynamic Model

Under the guidance of the strategy of transportation power and maritime power,China is accelerating the research and development of intelligent ship.Compared with general merchant ship,intelligent ship can not navigate independently or remotely without the support of shorebased center and competent shorebased operators.This paper focuses on the industry’s demand for intelligent ship shorebased center and simulation training system to solve two key problems.First,there is a lack of high-precision mathematic model of ship maneuvering motion in the process of off-line dynamic evolution of intelligent ship.Second,there is a lack of friendly ship data presentation and interactive carrier in the shorebased center of intelligent ship.The research is carried out on the numerical simulation of ship handling equipment,numerical simulation of ship maneuvering motion and digital twin intelligent ship simulation platform.The main research work is as follows:1)The CFD theory and marine dynamic simulation technology are summarized and discussed.The RNG k-ε model,SST k-ω model and RSM model used in numerical simulation are summarized.The finite volume method and the SIMPLE algorithm for solving the discrete algebraic equations are introduced.The latest uncertainty analysis procedures recommended by ITTC for ship numerical simulation are given.The 3D virtual scene modeling,3D scene and geometric transformation and collision detection algorithm of virtual objects involved in intelligent ship simulation platform are discussed.2)A series of numerical simulations are carried out on the hydrodynamic performance of propeller and semi-suspended rudder.The KP458 propeller of standard ship model KVLCC2 is used as the research object.The propeller characteristic coefficient and the surrounding flow field under different advance coefficient and turbulence model are simulated.The propeller thrust,torque and efficiency under different advance coefficient and turbulence model are analyzed.Based on the distribution of surface pressure,wake and vortex strength of propeller,the variation of propeller thrust coefficient is analyzed,and the generation region and variation of tip vortex and hub vortex are analyzed.The semi-suspended rudder of KVLCC2 ship model is used as the research object.The hydrodynamic performance and the surrounding flow field of the semi-suspended rudder at different angles of attack are simulated.The lift and resistance acting on the rudder horn and rudder blade are analyzed,and the surface pressure of the semi-suspended rudder and the flow vector distribution of the surrounding flow field are analyzed.The verification and validation on the numerical simulation results of propeller and semi suspended rudder are performed according to the latest ITTC uncertainty analysis procedures.Based on the numerical simulation of hydrodynamic performance of propeller and semi-suspended rudder,the interaction between propeller and semi-suspended rudder is simulated.The thrust coefficient and torque coefficient of propeller under interaction and open water are compared,and the influence of propeller-rudder distance on propeller hydrodynamic performance is analyzed.3)The flow field and hydrodynamic force of ship maneuvering motion are numerically simulated.The standard ship model KVLCC2 is used as the research object,and the oblique motion under different drift angles is simulated by CFD method.The resistance coefficient,transverse force coefficient and turning moment coefficient of the ship under the oblique motion are calculated.The numerical simulation results are compared with the experimental results of NMRI.The numerical simulation results are generally in good agreement with the tank experiment results.The pressure distribution,vorticity distribution and flow characteristics of ship hull surface under different turbulence models are analyzed.It is found that the turbulence model of SST k-ω is better for representing the pressure and vorticity distribution of the flow field around the ship.The verification and validation on the numerical simulation results of the ship are performed according to the latest ITTC uncertainty analysis procedures.Four kinds of motion conditions,such as oblique motion,towing motion under different rudder angles,sway motion and yaw motion,are simulated.The dimensionless hydrodynamic position derivative,control derivative,linear acceleration derivative,angular velocity derivative and angular acceleration derivative are calculated.4)The system architecture and key technologies in the development of intelligent ship simulation platform are studied.The online and offline system architecture of the intelligent ship simulation platform is established.The eleven main functions of the online mode as the virtual shorebased center and thirteen main functions of offline mode as the virtual training system are determined.Five interaction modes are designed,including keyboard mouse interaction,touch interaction,voice interaction,VR helmet interaction,and action recognition interaction.Based on numerical simulation method of benchmark KVLCC2,a mathematical model of manoeuvring motion of 57 000 DWT Panama bulk carrier "CHANG SHAN HAI" is established.The simulation experiments of 35° hard port and 10°/10° zigzag are carried out for the model.By way of the hierarchical structure of the three-dimension model,the whole three-dimension model with high reality and real-time performance is established.Based on the three-dimension model,the three-dimension interactive simulation of intelligent ship,such as scene roaming,fast navigation and moving and interactive behavior,are realized.The digital twin bridge of intelligent ship is established,and the typical navigation instrument simulators based on IEC61162 maritime standard data format are developed.The smooth data connection between navigation instrument simulators and real instrument is realized.Based on the above research results,an intelligent ship simulation platform with online and offline modes is developed.Through the numerical simulation and result verification of the international standard ship model KVLCC2,a high-precision mathematical model for the off-line dynamic evolution of the intelligent ship simulation platform is established.Through the research on the architecture and key technologies of intelligent ship simulation platform,the digital twin bridge of intelligent ship is developed,which solves the data presentation and interaction problems of intelligent ship virtual shore based center.The intelligent ship online simulation platform can be used as the virtual shorebased center of intelligent ship,which can receive and display the real ship data in real time.The intelligent ship offline simulation platform can be used as the virtual training system to provide high immersion simulation training for shorebased operators and crew.