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Research on Visual Simulation of Large Ship’s Direct Sailing Motion and Prediction of Motion Attitude

Author: LiMing
Tutor: JiMing
School: Harbin Engineering University
Course: Control Theory and Control Engineering
Keywords: Ship motion attitude Numerical simulation Visual simulation Prediction
CLC: U661
Type: Master's thesis
Year: 2012
Downloads: 48
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Abstract

Ship sailing in the ocean will produce tossing movement under wave loading. Ship’stossing movement will threat the safety of the taking off and landing of carrier plane.Therefore, ship’s seekeeping is a very important issue that designers should emphaticallyconsider.The study of simulation method on ship motion attitude in wave is helpful toevaluate the seakeeping of ships that designed by people. At the same time, the extremelyshort-time prediction of ship motion attitude can help crews make timely response to thenegative impact caused by ship’s tossing movement. That will reduce the occurrenceprobability of security incidents. Besides，the prediction of ship motion attitude can helppeople study the new control methods of stabilization devices. This paper studies thesimulation and prediction of large ship’s movement in direct sailing in wave. Therefore,the research on simulation of large ship’s direct sailing motion and prediction of motionattitude is carried out.Firstly, ship motion equations and disturbing force and moment equations is given. Themodel of disturbing force and moment of shipping produced by regular wave is establishedbased on Froude-Krylov assumption, so as to establish the model of disturbing force andmoment of shipping produced by long-crested wave. The slice theory is adopted to calculatethe hydrodynamic parameter and interference wave force coefficient of ship motion equations,so as to establish mathematical model which is suitable for simulating ship’s motion in directsailing. The thesis simulates the motion of one certain large containership sailing in directway in wave is carried out, and analyzes the simulation results and the motion rules aresummarized.Secondly, a visual simulation of ship’s motion attitude in direct sailing system is carriedout. Based on the different functions of system components, the system is divided into fourparts. That is ship3D model, numerical simulation module, virtual display of ship motionattitude model, and human-computer interaction module. Ship3D model is established byMultiGen Creator which is professional modeling software. The program used to solve theship motion equation is written by C++language, so as to complete the design of numericalsimulation module; Vega is used to establish the virtual ocean scene and realize the3-ddisplay of ship motion attitude; a human-computer interaction based on MFC is designed.Communication strategy between modules and program process control solution is designedin Visual C++6.0programming environment, so as to compile program for visual simulation system. Then ship’s motion attitude in direct sailing is simulated by the visual simulation, andthe simulation result shows that the system has good real-time performance and stronginteraction. The system can accurately predict the numerical simulation result of ship’smotion attitude in direct sailing and realistically represent ship motion attitude in virtualsence.Finally, Based on autoregressive model a prediction method for ship motion attitude isgiven. The recursive least square method with a Definite Memory is applied to the parameterestimation for prediction model, in order to solve the data redundancy problem that comesfrom the parameter estimation process through the method of ordinary recursive least squaremethod. The method to judge the order of prediction model is given, and a recursivepredicting model method is designed to predict the ship motion attitude. The ship motionattitude is predicted through the method, and the prediction result of the ship motion attitudeis satisfactory.

Research on Visual Simulation of Large Ship’s Direct Sailing Motion and Prediction of Motion Attitude

Abstract

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