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基于海况的船舶运动仿真关键技术研究
Key Technologies of Ship Motion Simulation Base on Sea State
【作者】 颜瓅;
【作者基本信息】 上海交通大学 , 机械工程, 2009, 硕士
【摘要】 本文的主要工作是建立了基于海况的船舶运动仿真,并将其结合到一个具有剧本流程和潜水器、机器人、潜水员等多个实体互动的援潜救生作业仿真系统中,提高了仿真系统的真实性。在船体运动方面,本文选择了基于频域的切片法作为运动模型。首先介绍了相关理论,包括如何获取船在不同频率下的水动力系数,如何计算船在波浪中的受力和力矩,最后建立船的运动微分方程组。本文的工作是,在仿真程序中通过龙格库塔法实时求解该方程组,计算各个时刻船的升沉和纵摇的数据。在海面运动方面,本文选择了基于海浪谱和Gerstner模型来构建海面。相关的理论包括,海浪谱的原理及如何用海浪谱计算海面上波的参数,如何使用Gerstner模型计算海面上水质点的位移,以及风级与海况等级的相关知识。本文从海况等级出发,近似地选择对应的三一波高,计算了各海况下波浪主要频率的上下限;然后设计了适当的网格,计算各个时刻水质点的运动,渲染生成一个动态的海面。在对船舶运动和海况研究结果的基础上,对两套算法的数据进行匹配,并设计了计算的流程并编写了相关代码,实现了基于海况的船舶运动;分析了一个现有的援潜救生作业的仿真系统的程序结构,确定合适的位置,将基于海况的船舶运动仿真作为一个模块结合进去,实现了增加新的功能后仿真程序仍能正常运行;优化了仿真系统的代码与模型,实现了在加入更多计算后程序的运行速度基本不变。运行仿真程序后,本文通过观察援潜救生船在海面上执行作业的情况,确认在4级海况下,波浪对援潜救生作业的安全性影响不大,作业过程是安全的。本文的创新在于,首次将海况与船体运动直接关联起来建立仿真,首次将船体在海浪中运动的仿真结合到一个具有作业剧本流程和多个实体互动的仿真系统中,提高了后者的真实性。本文的研究成果,还可以用于其它类型船舶的仿真,在应用前景方面具有明显的战略意义和实用价值。
【Abstract】 The main work of his paper is establish the ship motion simulation base on sea state, and combine with an existing simulation system for submarine supporting and lifesaving operation, improve the authenticity of this simulate system.In the aspect of ship hull motion, this paper chooses strip method based on frequency domain as motion model. First, introduce the related theory, including how to obtain ship hydrodynamic coefficients at different frequency, how to calculate ship force and moment in waves, how to build the ship motion differential equations at last. This paper’s work is real-time solve the equations with Runge-Kutta metho in simulation program, calculate ship’s heaving and pitching data at any moment.In the aspect of sea surface motion, this paper chooses the sea spectrum model and Gerstner model to build sea surface. Related theories including, the principle of sea spectrum and how to calculate wave parameters on sea surface with sea spectrum, how to calculate water parcel displacement on sea surface with Gerstner model, and the related knowledge on wind scale and sea state level. This paper correspond sea state to three-one average wave height approximately, determines upper limit and lower limit of the main wave frequency at different sea state; Then designs proper net, calculate water parcel motion, and renders a dynamic sea surface.Base the research of ship motion and sea state, this paper matches the data of two algorithms, designs calculate program, writes codes, realizes ship motion simulation base on sea state; Analyzes the program construct of the existing simulation system for marine rescue operation, determines the proper position, and combined with ship hull motion simulation base on sea state as a module, makes the simulation running normally after the new function has been inserted; Optimums the codes and models of simulation system, makes the running speed almost invariant after more function has been added.After running simulation program, this paper confirm that wave has limited influence for the safety of submarine supporting and lifesaving operation at sea state 4 by observing the situation of rescue ship executes operation on sea surface, the process of operation is safe.The innovations of this paper are, first directly associate sea state and ship hull motion to build simulation, first combine the simulation of ship hull motion in sea wave with a simulation system with work flow and multiple entities, improves latter’s authenticity. The research result of this paper could be used in simulation of other ship types, and has obvious strategic significance and practical value at application prospect.
【Key words】 pitching; heaving; ship motion simulation; sea state; wave spectrum; ocean wave simulation;