一种基于改进蚁群算法的载人潜水器全局路径规划

当前关于使用蚁群算法解决载人潜水器路径规划问题的研究,往往只注重路径的长度和算法收敛速度,容易忽略路径点与障碍物之间的距离和路径的平滑度等要素。载人潜水器过于靠近障碍物航行时容易产生碰撞;按照不平滑路径行驶时,频繁地转向会降低航行效率。为解决这些问题,受人工势场法启发,文中在蚁群算法的概率选择环节引入障碍物惩罚因子φ和转向惩罚因子ψ,对路径点的选择加以限制。仿真测试表明,相比于传统蚁群算法和Dijkstra算法,该算法规划的路径与障碍物之间保持安全距离且转向次数更少,因此载人潜水器按照此路径航行时,安全性和航行效率更高。     

不同方式的纳潮量计算比较——以胶州湾2006年秋季小潮为例

以胶州湾为例,分别通过纳潮量常用算法和走航ADCP直接测流资料计算了2006年秋季小湖期间3个不同潮对段的纳湖量.结果表明,根据纳潮量常用算法得到的纳潮量变化范围大干采用测流资料计算得到的纳潮量范围.在平均意义上,两种算法的平均值分别为6.303×108m3和6.480×108m3,仅相差O.177×108m3.这既验证了通过海流计算纳潮量的精确性,也体现了通过纳潮量算法计算纳潮量在平均意义上的有效性.     

浮山湾帆船赛场水动力条件数值模拟

潮流数值计算是研究海域现状潮流场及预测潮流场分布的一个重要方法.根据帆船比赛的要求,结合青岛浮山湾及邻近海域的地理信息,应用分步杂交方法建立浮山湾变边界潮流数值模型进行模拟计算,分析浮山湾帆船赛场的水动力条件,从潮波、海水流速等方面证明选址的合理性.结果表明,浮山湾及附近海域的水动力和气候务件等均能够满足帆船比赛的要求.     

全姿态水下移动平台模式切换姿态控制研究

为了适应复杂海洋环境中多样性的观探测任务需求,本文提出了一种融合Argo浮标、水下滑翔机（Glider）和自治式水下机器人（Autonomous Underwater Vehicle,AUV） 3种工作模式的全姿态水下移动平台（All-attitude Multimode Underwater Vehicle,AMUV）。首先,基于3种水下移动平台的工作原理,建立了AMUV的六自由度动力学模型;然后,针对动力学模型中的非线性耦合特性及模式切换过程中的驱动位形变化等问题,基于比例、积分、微分控制器（Proportional Integral Derivative,PID）与模糊控制概念,设计了不依赖于数学模型的自适应模糊PID姿态控制器,实现了AMUV多模式切换过程中的姿态控制;最后,开展多模式切换控制仿真实验,将自适应模糊PID控制器与传统PID控制器仿真结果进行对比,并设计了全模式任务工况,仿真结果表明,本文提出的控制器能够精确和稳定地控制AMUV进行多种工作模式的相互切换。     

河海、陆海分界的科学、法律依据

从科学和法律的观点,讨论了河海、陆海的分界问题.从自然科学的角度考虑,河、海间的过渡段是河口,陆、海间的过渡段是滩涂.否定这两个过渡段的客观存在及其自然属性是不现实的和不明智的.河口是河流与海洋相互作用的地段,潮流与径流是河口物质、能量输移的两个主要动力因素;而海洋的主要动力除潮流外,还有波浪、密度流、各类海洋环流,径流已微不足道.滩涂是随高、低潮位变化而时淹时露的一片陆地,而海洋则主要是指低潮位以下的水体,两者自然属性有明显的差异.但河口与海洋、滩涂与海洋在学术研究中难免存在交叉,相比之下,自然科学、法律条文对上述一些用语的定义、内涵则更加严格.目前法律上对海域论述最权威的应是1994年通过的、我国也签约的<联合国海洋法公约>.该法对海岸基线、内水、河口、海域、海湾均有科学、严格的定义,将名词的科学性与法律的严肃性、可操作性完美地结合在一起.全国人大于1996年5月批准执行此法,它应是我国海洋法系统的法律基础,其它的法律文件(包括名词定义与基本精神)不能与之相冲突.引用了国内外海洋法的条文、权威的学术专著及相关论文,从科学及法律条文上明确的定义看,领海基线即低潮位线是陆-海及河-海的分界线,也是量算领海距离、划分内水与海域的基准线,内水是领海基线向陆一侧的水域,包括河流、河口、海湾及滩涂的水体等.因此内水不限于海域,而2001年我国人大通过的<海域法>未明确河口及滩涂的法律地位,而且正是该法将内水表述为海域的组成部分,与<联合国海洋法公约>将内水不包括在海域之内相矛盾,故执行中常发生争议.     

青岛浮山湾数值化海区建立的研究——浮山湾潮流模型的数值计算

应用二维潮流数学模型(在近岸海域采用不规则三角形网格有限差分方法)对青岛浮山湾的潮流场进行了数值模拟计算,并预测了工程建成后海区流场的变化。数值模拟结果表明,帆船比赛基地港池及附近水域计算区域内验证点的模拟流速与原型观测值一致,较好地再现了浮山湾的流场变化情况,为2008年北京奥运青岛帆船赛场的规划和建设提供了科学依据。     

Implementation of High Resolution Tidal Current Fields in Electronic Navigational Chart Systems

A system for displaying tidal currents in an electronic chart display and information system (ECDIS) has been developed and implemented in compliance with the standards of the International Hydrographic Organization (IHO). The tidal current fields can be displayed in real time on the electronic navigational chart and several options and functions for updating and zooming have been designed. The current fields are calculated from a data base with the harmonic constants for the four major tidal constituents. The harmonic constants are obtained from a high resolution numerical model with horizontal grid resolution of 100 m. The model is validated by comparing with sea level and current measurements. The depth matrix for the central part of the model domain was calculated from data from multibeam bathymetric surveys. An application example of the implementation is given for Trondheimsleia, a part of the main sailing route along the western coast of Norway.     

Adaptive fuzzy controller design for dynamic positioning system of vessels

This paper develops an adaptive fuzzy controller for the dynamic positioning (DP) system of vessels with unknown dynamic model parameters and unknown time-varying environmental disturbances. The controller is designed by combining the adaptive fuzzy system with the vectorial backstepping method. An adaptive fuzzy system is employed to approximate the uncertain term induced by unknown dynamic model parameters and unknown time-varying environmental disturbances. It is theoretically proved that the proposed adaptive fuzzy DP controller can make the vessel be maintained at the desired values of its position and heading with arbitrary accuracy, while guaranteeing the uniform ultimate boundedness of all signals in the closed-loop DP control system of vessels. Simulation studies with comparisons on a supply vessel are carried out, and the results illustrate the effectiveness of the proposed control scheme.     

钱塘江涌潮对地形变化的响应研究

钱塘江涌潮以汹涌磅礴闻名中外,并对沿江防灾减灾带来巨大挑战,研究涌潮规律具有重要的学术价值和现实意义。采用涌潮数学模型研究钱塘江涌潮在地形变化下潮汐和涌潮特征的变化。结果表明,地形变化对潮汐和涌潮影响显著;随着地形的降低,钱塘江沿程低潮位下降,高潮位总体呈下降趋势,潮差增大,涨潮历时增加;涌潮高度和涌潮最大流速随相对Froude数呈先增后减规律,起潮点上移,涌潮传播速度增大;当地形降低到临界值后,相对Froude数小于1,涌潮消失。研究结论解释了钱塘江丰水地形涌潮大、枯水地形涌潮小的现象。为保护涌潮资源,维持适当的江道容积是必要的。     

Robust optimal output tracking control of a midwater trawl system based on T-S fuzzy nonlinear model

A robust optimal output tracking control method for a midwater trawl system is investigated based on T-S fuzzy nonlinear model.A simplified nonlinear mathematical model is first employed to represent a midwater trawl system,and then a T-S fuzzy model is adopted to approximate the nonlinear system.Since the strong nonlinearities and the external disturbance of the trawling system,a mixed H 2 /H ∞ fuzzy output tracking control strategy via T-S fuzzy system is proposed to regulate the trawl depth to follow a desired trajectory.The trawl depth can be regulated by adjusting the winch velocity automatically and the tracking error can be minimized according to the robust optimal criterion.In order to validate the proposed control method,a computer simulation is conducted.The simulation results indicate that the proposed fuzzy robust optimal controller make the trawl net rapidly follow the desired trajectory under the model uncertainties and the external disturbance caused by wave and current.     

On the track keeping and roll reduction of the ship in random waves using different sliding mode controllers

In the paper, an autopilot system composed of sliding mode controller and line-of-sight guidance technique are adopted to navigate the ship in random waves by altering the rudder deflection. Two kinds of sliding mode controller are considered; one is the separate system including sway–yaw control and roll control, the other is the compact system considering sway–roll–yaw control altogether. Both track keeping and roll reduction are accomplished by rudder control and the design parameters of controller are optimized by genetic algorithm. The present simulation results show both the separate controller and the compact controller work quite well, either for track keeping or roll reduction while the ship is sailing in random waves. However, the separate controller is recommended due to its simplicity.     

Maneuvering control and trajectory tracking of very large crude carrier

This paper presents a complex control system of the ship motions in confined waters. The general structure of this system is based on the two different controllers connected in parallel. They are dedicated to the different tasks and operate in different conditions. One of them is based on the robust control technology while another is based on the fuzzy logic technique. To decide which controller to use depends on the velocity of the vessel. The control system was implemented at the first stage on a nonlinear multi-variable simulation model and at the second stage on a real-time object—floating, autonomous model of the very large crude carrier (VLCC tanker). The whole system was developed in the MATLAB/Simulink platform.     

基于蚁群算法的水下传感网网络生存期延长策略研究

随着海洋强国战略的推进和实施,水下传感器网络广泛应用于海洋资源探测、污染监测、辅助导航和水下军事侦察等领域,具有十分重要的意义。由于水下传感器所携电池充电或更换困难,如何减小传输能耗、在传感器能量受限的情况下提升网络生存期是亟须解决的关键问题之一。据此,提出了一种动态蚁群路由算法,考虑了每次传输后的节点剩余能量,作为路径优化的条件之一,基于蚁群算法在每次传输中选择最优路径,并在每次传输完成后更新路由表,让更多的节点参与信息传输,以提高节点的利用率。仿真结果表明：动态蚁群路由算法同时兼顾了能耗平衡和最小传输能耗,大大提高了网络生存期。分析结果对水下传感器网络的路由协议设计有一定的参考意义。     

Tidal and river discharge forcing upon water and sediment circulation at a rock-bound estuary (Guadiana estuary,Portugal)

The relative impacts of tidal (neap, spring) and river discharge (including a flood event) forcing upon water and sediment circulation have been examined at the rock-bound Guadiana estuary. Near-bed and vertical profiles of current, salinity, turbidity, plus surface suspended sediment concentrations (SSC, at some stations only), were collected at the lower and central/upper estuary during tidal and fortnightly cycles. In addition, vertical salinity and turbidity profiles were collected around high and low water along the estuary. Tidal asymmetry produced faster currents on the ebb than on the flood, especially at the mouth. This pattern of seaward current dominance was enhanced with increasing river flow, due to horizontal advection that was confined within the narrow estuarine channel. The freshwater inputs and, at a degree less, the tidal range controlled the vertical mixing and stratification importance. Well-mixed (spring) and partially stratified (neap) conditions alternated during periods of low river flows, with significant intratidal variations induced by tidal straining (especially at the partially stratified estuary). Highly stratified conditions developed with increasing river discharge. Intratidal variability in the pycnocline depth and thickness resulted from current shear during the ebb. A salt wedge with tidal motion was observed at the lower estuary during the flood event. Depending on the intensity of turbulent mixing, the residual water circulation was dominantly controlled either by tidal asymmetry or gravitational circulation. The SSC was governed by cyclical local processes (resuspension, deposition, mixing, advection) driven by the neap-spring fluctuations in tidal current velocities. More, intratidal variability in stratification indicated the significance of tidal pumping at the partially and highly stratified estuary. The estuary turbidity maximum (ETM) was enhanced with increasing current velocities, and displaced downstream during periods of high river discharge. During the flood event, the ETM was expelled out of the estuary, and the SSC along the estuary was controlled by the sediment load from the drainage basin. Under these highly variable river flow conditions, our observations suggest that sand is exported to the nearshore over the long-term (>years).     

一个潮流不对称计算方法及其在北仑河口的应用

河口近岸海域潮流不对称对于物质输运、地形地貌变化有重要作用,因此研究河口近岸海域潮流不对称具有重要的意义。从统计学角度出发推导了一种潮流不对称的计算方法,并将该方法应用于全日潮类型的北仑河口。研究认为:从三阶原点矩出发推导的计算方法能够合理的量化潮流不对称;潮流不对称的方向由分潮的相对相位决定,不同分潮对潮流不对称的影响大小由其相对振幅和相对相位共同决定;在正规全日潮海区,三阶原点矩即可满足对潮流不对称的计算。北仑河口潮流表现为落潮流速占主导,潮流不对称空间上表现为口门强于外海,浅滩强于深槽。     

九龙江河口湾泥沙运移特点与沉积动力机制

本文研究了九龙江河口湾的泥沙动物特点与沉积动力机制。结果表明：（１）泥沙主要来地河流输沙和潮流输沙;潮流输沙星明显大于河流输沙星;涨潮输沙星通常大于落潮输沙量;潮流输沙在枯水期尤为显著,而河流输沙则集中在洪水期。（２）底沙推移运动主要发生在水道床面,系局部冲刷所致;推移质输沙表现为沙洲推移,沙嘴延伸或水下沙体游移,研究发现,在涨潮流占优势的鸡屿北水道有反向,推移质输输沙的迹象。（３）自６０年代以来     

Unscented Kalman Filter trained neural networks based rudder roll stabilization system for ship in waves

The large roll motion of ships sailing in the seaway is undesirable because it may lead to the seasickness of crew and unsafety of vessels and cargoes, thus it needs to be reduced. The aim of this study is to design a rudder roll stabilization system based on Radial Basis Function Neural Network (RBFNN) control algorithm for ship advancing in the seaway only through rudder actions. In the proposed stabilization system, the course keeping controller and the roll damping controller were accomplished by utilizing modified Unscented Kalman Filter (UKF) training algorithm, and implemented in parallel to maintain the orientation and reduce roll motion simultaneously. The nonlinear mathematical model, which includes manoeuvring characteristics and wave disturbances, was adopted to analyse ship’s responses. Various sailing states and the external wave disturbances were considered to validate the performance and robustness of the proposed roll stabilizer. The results indicate that the designed control system performs better than the Back Propagation (BP) neural networks based control system and conventional Proportional-Derivative (PD) based control system in terms of reducing roll motion for ship in waves.     

海道测量规范与IHO标准的比较研究

为保障船舶航行安全,国际海道测量组织制定了国际海道测量标准并保持不断更新,我国也根据自身情况制定了海道测量的国家强制标准。从测深、定位、障碍物、潮位、潮流和底质等6个方面对国际海道测量标准和我国海道测量规范进行了分析比较,指出了它们在要求上的不同和差异,旨在供测量人员在实际工作中参考使用并推动国内测量规范与国际测量标准的衔接。     

Robust adaptive control of underactuated ships on a linear course with comfort

This paper addresses an important problem in ship control application—the robust stabilization of underactuated ships on a linear course with comfort. Specifically, we develop a multivariable controller to stabilize ocean surface ships without a sway actuator on a linear course and to reduce roll and pitch simultaneously. The controller adapts to unknown parameters of the ship and constant environmental disturbances induced by wave, ocean current and wind. It is also robust to time-varying environmental disturbances, time-varying change in ship parameters and other motions of the ship such as surge and heave. The roll and pitch can be made arbitrarily small while the heading angle and sway are kept to be in reasonably small bounds. The controller development is based on Lyapunov’s direct method and backstepping technique. A Lipschitz continuous projection algorithm is used to update the estimate of the unknown parameters to avoid the parameters’ drift due to time-varying environmental disturbances. Simulations on a full-scale catamaran illustrate the effectiveness of our proposed controller.     

大深度载人潜水器低速大漂角模糊滑模航向控制研究

通过模型试验测量大深度载人潜水器低速大漂角运动时所受到的非线性水动力。基于一种新的模糊滑模控制策略,为潜水器设计了鲁棒航向控制器。在不同的漂角子区间内分别设计局部镇定的滑模控制器,然后通过Takagi-Sugeno模糊推理系统将它们光滑连接,得到模糊滑模控制。仿真计算结果充分显示了该控制策略的有效性。