【作者】 王海波；

【导师】 王庆丰；

【作者基本信息】 浙江大学 ， 机械电子工程， 2009， 博士

【摘要】 水下拖曳系统在海洋学研究、海底资源开发、海洋打捞救助以及水下目标探测等方面具有广泛的应用,一般由拖体、拖缆和收放拖曳装置组成。系统在海洋中拖曳作业时,拖船在海面的升沉运动引起拖体深度和拖缆张力的变化,并随着海况的恶化而加剧。较高海况下拖船的剧烈运动不仅影响拖体中传感器的正常工作,而且给拖体和拖缆的安全造成很大威胁。为保证水下拖曳系统在恶劣海况下能够正常进行拖曳作业,其必须具备升沉补偿功能。当前国内对拖曳升沉补偿的研究基本处于空白,因此论文对其进行的研究工作具有重要意义。针对以上问题,论文以一种重型拖曳系统作为研究对象,补偿拖船升沉运动对拖体深度的影响作为研究目标,通过理论分析、建模仿真和试验研究,掌握拖曳升沉补偿系统被控对象的基本特性,研究适合于拖曳升沉系统的液压系统和控制策略,为具有拖曳升沉补偿的水下拖曳系统的设计开发提供设计依据,具有重要的学术价值和工程应用前景。论文各章内容分述如下:第一章概述了水下拖曳系统,介绍了拖曳升沉补偿系统的工作原理和分类,回顾和综述了拖曳升沉补偿及其相关领域的研究现状,最后,提出了本论文的研究意义和主要研究内容。第二章设计了拖曳升沉补偿系统收放装置的液压系统,分别采用比例方向阀和电磁换向阀控制收放架的水平运动和变幅运动,开式容积调速回路控制拖缆绞车转动实现拖体的收放操作,提出了基于前馈补偿的恒张力同步收放控制策略。陆上和海上试验研究表明,设计的收放装置液压系统和提出的同步控制策略性能优异,取得了满意的效果。第三章分别提出了被动拖曳升沉补偿液压系统回路,基于进油、回油节流切换控制的单马达驱动主动拖曳升沉补偿液压系统回路和集成被动补偿、主动补偿的双马达驱动半主动拖曳升沉补偿液压系统回路,并结合拖缆、拖体的简化模型建立了液压系统数学模型,建立了主动拖曳升沉补偿液压系统的试验装置并进行了试验。建模分析表明,被动系统补偿能力有限;主动系统设计灵活,具有更好的补偿性能;半主动系统不仅设计灵活,补偿性能好,而且动力消耗小,安全可靠;试验研究表明,主动系统响应快,调速性能好。第四章建立了垂直面内拖曳升沉补偿系统被控对象——拖缆和拖体的水动力数学模型及其初始、边界条件,其中拖缆动力学模型基于Ablow&schechter模型,拖体采用水下运载体六自由度方程的简化形式模拟;应用摄动理论求解了数学模型在其平衡位置附近的近似解析解,运用有限差分法离散数学模型偏微分方程组,采用牛顿迭代法计算了拖缆上各计算节点的张力和拖体深度的变化;最后,利用数值计算结果对系统被控对象的输入输出参数化数学模型进行了分析。近似解析解分析和数值计算结果表明,拖曳升沉补偿系统较短的拖缆释放长度使拖缆张力变化不会与拖船升沉运动干扰信号产生共振,变化范围有限;输入输出参数化数学模型分析表明,拖体深度与拖船升沉运动位移、拖缆绞车收放运动位移之间的关系是一个随着拖船航速变化的时变非线性函数。第五章提出了拖曳升沉补偿控制系统总体方案,它具有内层位置伺服控制子系统和外层深度升沉补偿控制子系统双层结构,其中,内层子系统在时变拖缆张力扭矩干扰下实现对目标位移的快速、无静差跟踪;外层子系统确定拖缆绞车运动目标位移以补偿拖体深度变化。分别设计了采用内模控制策略的内层子系统控制器和基于紧格式线性化非参数模型自适应控制理论的外层子系统控制器,并分别对内层子系统、外层子系统和拖曳升沉补偿控制系统进行了仿真。仿真表明,内层位置伺服控制器抗干扰能力强,鲁棒性好,对系统模型要求低和参数整定方便;外层升沉补偿控制器设计简单,对具有时变非线性特性的控制对象具有较高的补偿精度;拖曳升沉补偿控制系统在各航速下都能够有效抑制拖船升沉运动对拖体深度的影响。第六章概述了论文的主要研究工作和成果,并对今后的研究工作和方向进行了展望。更多还原

【Abstract】 An underwater towed system generally consists of towed body, cable, retraction and towing device. It is used extensively for ocean exploration. Examples include oceanography, ocean resource development, ocean salvage, underwater target detection and so on. When it is working in the ocean, heave motion of the towed ship on the rough sea leads to change of the towed body depth and the cable tension. Obviously, the situation will become more severe with higher sea state. Violent motion of the towed ship may not only disturb the ability of sensors installed in the towed body to perform a task, but also present a great threat to the safety of the towed body and the cable. In order to ensure that the underwater towed system is able to work in the bad sea condition, it must have heave compensation function. At present there is almost no study on this key technology of the underwater towed system in China, therefore the research on towed heave compensation is very significant.Under the background of the above-mentioned, a heavy underwater towed system is selected as the object of study and compensating the influence of heave motion of the towed ship to the towed body depth is the research objective. Through theoretical analysis, modeling, simulation and experiments, the fundamental feature of the controlled object of the towed heave compensation system is understood and the hydraulic system and control strategies which are suitable for the towed heave compensation system are studied. All these works provide some design basis for developing the underwater towed system possessing heave compensation function. They have important academic value and a bright future for engineering application.The main contents of each chapter are summarized as following.In chapter 1, a general view of the underwater towed system is given at the beginning. Then the work principle and classification of the towed heave compensation system are introduced. Present study state of the towed heave compensation system as well as its related fields is overviewed. The research significance and main study contents of this dissertation are put forward at the end.In chapter 2, launch and recovery hydraulic system in which the crane is driven by proportional directional valve and electromagnetic directional valve to carry out horizontal and variable-amplitude motion respectively, and the winch is driven to implement retrieval and release of the towed body by open volumetric speed control is designed. Constant tension synchronous control strategy based on feed forward compensation is proposed. The results of land and sea experiments demonstrate that the designed hydraulic system and proposed synchronous control strategy both have good performance and achieve a satisfied effect.In chapter 3, a passive towed heave compensation hydraulic system, an active towed heave compensation hydraulic system driven by single motor and based on meter-in, meter-out switch control principle, and a semi-active towed heave compensation hydraulic system driven by double motors and having passive and active compensation units are designed. The mathematical models of these hydraulic systems are built with simplified model of the towed body and the cable. In addition, the experiment equipment of the active towed heave compensation hydraulic system is established. The mathematical model analysis shows that the passive system has limited capability, and the active system and the semi-active system are both flexible in design and has higher compensation performance. But compared with the active system, the semi-active version has lower power assumption, higher safety and reliability. Experiments of the active system show that it has good speed regulation performance and quick response.In chapter 4, dynamic model, boundary conditions and initial conditions of the towed heave compensation system are established in normal plane. The equations of the towed cable motion are based on Ablow and Schechter model and the simplified version of six degree-freedom ordinary differential equations are used in motion analysis of the towed body. By perturbation theory, dynamic model of the towed heave compensation system is solved approximately about equilibrium positions. The partial differential equations of the dynamic model are discreted by finite difference method and the transient values of each node in the cable are computed by Newton Iteration. At the end, the input and output parametric model of the towed heave compensation system is analyzed by using numerical calculation results. The analysis of the dynamic model shows that short length of the cable in the towed heave compensation results in that there is none sympathetic vibration between tension in the cable and heave motion of the towed ship, and tension change in the cable is small. The analysis of the input and output parametric model of the compensation system shows that the interrelationship of depth of the towed body, heave motion of the towed ship and retraction of the winch is a time-variable nonlinear function with speed change of the towed ship.In chapter 5, the general control scheme for the towed heave compensation system which is composed of an external depth heave compensation control subsystem and an inner position servo-control subsystem is proposed. The inner subsystem rapidly tracks the reference displacement without steady-state error under time-variable tension torque disturbance, while the external subsystem determines reference displacement of the winch to compensate depth change of the towed body. The inner controller designed by internal model control principle and the external controller designed by the nonparametric model adaptive control approach based on a dynamic linearization of tight format are introduced. Finally, the inner subsystem, the external subsystem and the towed heave compensation control system are respectively simulated. Simulation shows that the inner controller has strong robustness and good ability to resist disturbance, its demands for modeling precision are low, its parameter setting is convenient, and the external controller is simple in design and has high accuracy in case that the control object has time-variable nonlinear feature, and the towed heave compensation control system is able to effectively inhibit influence of heave motion of the towed ship on depth of the towed body at every speed of the towed ship.All achievements of the dissertation are summarized and the further research work is put forward in chapter 6.更多还原