【作者】 吴开塔；

【导师】 连琏；

【作者基本信息】 上海交通大学 ， 船舶与海洋结构物设计制造， 2011， 硕士

【摘要】 随着海洋活动的进一步开展、海洋资源的深入开采以及近年来国内外海底观测网技术的大力发展,无人遥控潜水器(ROV)被越来越广泛地得到应用。但是,母船在波浪作用下产生横摇、纵摇和升沉运动,这种运动特别是升沉运动通过主脐带传递到吊放的ROV等水下设备,将导致设备无法正常工作或对连接的缆索或脐带系统造成破坏。因此,有必要研制一套升沉补偿系统,以减小升沉耦合运动传导、吸收加速度动力、减少脐带松弛,以改善ROV运动控制条件、防止脐带缆破坏、提高系统作业安全性。本文源自国家863重点项目——“4500m深海作业系统”,其目标是研制一套实用化的强作业型深海遥控潜水器(ROV)及其作业工具系统(水下升降装置、升沉补偿器、水下作业与救援工具等),以实现海底探测和取样、深海海底观测网布放和维修等作业功能。本文采用理论分析、计算机仿真和模型实验相结合的方法,对ROV系统的被动式升沉补偿器进行了研究。首先,论文在深入分析国内外现有的各种升沉补偿技术及各自优缺点的基础上,确定以串联被动式升沉补偿器作为4500m ROV系统的升沉补偿方案。同时根据4500m ROV的本体结构特征和吊放使用的脐带缆参数以及海况特征,提出了补偿器的性能指标,并对其进行了参数设计。其次,由于所设计的被动式升沉补偿器是非线性弹性系统,本文对串联被动补偿器的带缆式ROV系统建立了完整的动力学模型,推导并计算出系统在不同深度下的弹性刚度、自然周期等特性,并采用经典四阶龙格库塔法解微分方程、使用MATLAB仿真的方法,计算了系统在三种典型海况下的动力响应,进而分析补偿器的补偿性能,还对脐带缆弹性的影响进行了分析。此外,针对补偿器系统在长周期海况下,特别是大深度作业时,补偿效率低,甚至可能产生共振的问题,本文提出了在补偿器设置流量调节阀调节系统阻尼来提高补偿效率的解决方案,并对该方案通过数值仿真计算进行了验证。最后,本文对被动式补偿器进行了缩尺比为1:4的模型试验研究,通过模拟补偿器在不同海况和ROV不同作业深度下的补偿效果,来验证和提高设计及计算分析的可靠性,并为实际系统提供经验。更多还原

【Abstract】 With the expansion of marine activities and the deep-going exploitation of marine resources, as well as the rapid development of Seafloor Observatory Network in recent years, Remotely Operated Vehicle (ROV) is becoming more and more widely used in these areas. However, the roll, pitch and especially the heave motion of the mother ship might transmit through the umbilical tether to the Vehicle body, which might futhur cause operational failure to the vehicle or result in damage to the tether. Therefore, a heave compensation system is needed to reduce the induced vehicle motion, alleviate the dynamic tension and avoid slack of the tether which is a precause of snap load, so as to improve the vehicle control condition and prevent cable destruction, with an aim to enhance the operational safety.This paper is part of the National High Technology Research and Development Program project: 4500m Deep Ocean System, which is designed to develop a strong work class ROV and its operating tool system, including the Underwater Elevator, the Heave Compensator, the Operating and Rescuing Tools, as to complete such underwater tasks as seabed surveying and sampling, seafloor observatory network deploying, installing and repairing. This paper conducts the research of passive heave compensator for tethered ROV system through theoretical analysis, computer simulation and model experiment.Firstly, after studying the existing compensation technologies at home and abroad, and analyzing their pros and cons, the paper selects the flying sheave heave compensator as the compensation scheme for 4500m ROV system. At the same time, it figures out the compensator performance objective based on the designed ROV vehicle body and the umbilical tether parameters, thus designs the compensator parameters.Secondly, as the passive compensator is a nonlinear system, this paper builds the overall dynamic model of the whole in-line flying sheave heave compensation tethered ROV system, deduces and calculates the system characteristics like, the spring stiffness and natural period. Numerical simulations of system response in three typical kinds of sea state conditions, solved by the classic fourth-order Runge-Kutta scheme were done, so as to verify the compensator performance. Besides, it analyses the impact of tether’s elasticity. To the question of low compensation efficiency and even the resonance situation in long seas, especially in deep water, the paper proposes a novel idea of adding a valve to regulate the system damping to solve that problem, and verifys this idea through numerical simulation later.Finally, this paper carries out the reduced scale model experimental research, simulates compensator response in different sea states and in various operating depths, to verify and improve the reliability of calculation analysis, while providing experiences for the real system.更多还原