螺旋桨驱动UUV推进系统研究

为了实现水下机器人(UUV,Unmanned Underwater Vehicle)的高精度控制,深入研究了螺旋桨驱动UUV推进系统各个环节运行机理,并建立了它们各自的数学模型,包括PWM模块、直流永磁电机、螺旋桨、舵的数学模型。多功能仿真试验和湖试试验的系统响应曲线基本吻合,一方面表明本文建立的推进系统模型的正确性,另一方面体现了在多功能仿真平台上调试的控制策略和控制器参数具有很大的可信度。

基于时延Petri网的多UUV系统的任务分配策略

针对多水下机器人(unmanned underwater vehicle,UUV)系统动态任务分配问题展开研究,在对系统的体系结构和任务分配机制进行分析的基础上,利用时延 Petri 网理论对系统的任务分配进行建模,提出了一种新的任务分配策略:群体协调层采用集中式任务分配策略,由主 UUV 将任务实时下达给各从 UUV;监控规划层采用基于适应度的分布式任务分配方式,充分发挥各异构 UUV 自身的智能。仿真结果验证了模型的合理性和任务分配策略的有效性。

基于跟随领航者法的多UUV队形控制方法研究

本文主要研究基于跟随领航者法的多 UUV(unmanned underwater vehicle)队形控制。在 UUV 载体坐标系下建立系统的运动学模型,该模型是对笛卡尔坐标系下的运动学模型的改进,避免了极坐标系下奇异点的出现。该模型经过输入输出反馈线性化,获得稳定的队形控制器。同时,为了缩小队形控制律中的控制参数的调整范围,本文提出了辅助算法,在此基础上分析参数的有效范围。将队形控制律在多 UUV 数字仿真平台上验证,证实了改进的运动学模型和控制律的有效性。

面向多目标搜索的多UUV协作机制及实现方法研究

由不同功能UUV组成的异构系统能够实现对水下多个目标的探测和识别，多台UUV的协作机制已经成为当前水下机器人领域的一个热点课题。论文的研究工作依托国家863计划“基于弱通信的多机器人协调控制关键技术研究”等多项课题，面向水下多目标搜索应用背景，针对水下声学通信以及探测、导航传感器的局限性，研究弱通信条件下异构多UUV系统协作机制及实现方法，具体研究内容包括如下几个方面： (1) 构建了异构多UUV系统的体系结构：提出了基于多智能体角色联盟的UUV群体体系结构，使其能够适应多重的使命需求，具有开放性。设计了基于智能体思维结构的UUV个体体系结构，将UUV智能体的思维状态分为个体心智和社会心智两个层次分别实现，更加符合人类社会思维模式。基于面向对象Petri网理论对角色联盟进行建模，能够对角色内部控制逻辑和角色之间协作逻辑进行描述。 (2) 设计了多UUV系统的编队搜索策略：面向多目标搜索应用设计了编队搜索策略，保证搜索区域的连续性，采用基于大地坐标系的队形结构，更易于转弯时的队形控制。提出了基于思维层规划的队形控制方法，将跟随领航者法集成到队形控制任务的规划中，方便在不同任务间的切换，具有通用性。此外，设计了多UUV系统的队形重规划策略。 (3) 研究了多UUV系统的任务分配方法：针对同步搜索中的分布式任务分配问题，提出了动态熟人网方法，该方法对传统熟人网方法进行了改进和扩充，能够满足弱通信条件下任务分配的响应时间、执行时间、可靠性和负载均衡等性能要求，将动态熟人网方法应用于目标识别任务分配问题，仿真结果表明动态熟人网相比传统熟人网具有更好的性能。针对异步搜索中的多目标优化任务分配问题，提出了多蚁群系统（MACS）算法，该算法针对多个目标的不可公度性，对现有蚁群系统（ACS）算法进行了扩展，将MACS方法应用于多目标优化任务分配问题，仿真结果显示MACS算法相比加权法ACS具有更好的性能。 (4) 研究了多UUV系统低成本自主导航方法：提出了基于移动双信标的协作导航方法，采用两台携带高精度导航传感器的主UUV，为数量不限的携带低精度导航传感器的从UUV提供导航信息。设计了基于扩展卡尔曼滤波器的从UUV位置估计算法，该方法能够有效提高从UUV的导航精度，并且适应弱通信条件。 多UUV仿真平台的实验结果验证了本文提出的协作机制及实现方法是正确有效的，能够满足弱通信条件下多目标搜索的实际需求。

基于水声通信的多UUV系统网络协议研究

随着海洋作业需求的不断复杂化和多样化，单台水下机器人的功能逐渐显示出一定的局限性。于是由多台水下机器人组成的协作系统逐渐成为研究热点。多水下机器人系统具有稳定性和可靠性高、探测范围广、功能丰富、工作效率高等特点、在海洋水文数据取样、水下目标搜索、海洋资源勘探等许多方面有着广阔的应用前景。多水下机器人系统能够进行协同作业的基本前提是在水下机器人之间的存在可靠而高效的水声通信网络。为了克服多水下机器人网络中存在的低信道带宽、长传播延时、低信道稳定性、节点能量受限等诸多困难，设计适用于多水下机器人网络的通信协议成为多水下机器人领域的重要的基础性的课题，具有重要的理论和现实意义。 本文首先研究了多水下机器人水声通信网络技术的发展历史和概况。然后从水下机器人和水声通信网络两方面研究了多水下机器人水声通信网络的特点、难点。在水声通信网方面，分析了网络拓扑、物理层和数据链路层的现有解决方案，并结合了多水下机器人水声通信网络的特点，选择了合适的网络拓扑，物理层水声通信机、数据链路层媒介访问控制协议作为研究工作的起点。 然后，本文根据多水下机器人水声通信网络的特点，研究了多水下机器人水声通信网络协议设计的基本思想，并依据该思想设计并实现了多水下机器人水声通信网络协议。该网络协议在退避算法、能量控制、媒介访问控制、序号机制、捎带机制、网络地图等方面做了一定的改进。 接着，为了方便调试、评估该网络协议，本文首先建立了水声通信的经验模型，并在此基础上设计并实现了一个基于局域网的多水下机器人水声网络协议仿真系统。在该仿真系统上，本文对协议进行了仿真和分析，仿真结果表明本文所设计的协议要优于原型协议。 最后，本文对多水下机器人水声通信网络的几个问题进行了探讨，并作了总结与展望。

“探索者”号无缆水下机器人水下回收系统的设计与应用

本文详细介绍了"探索者"号无缆水下机器人水下回收系统的设计思想及电控系统的实现方法.本系统分为水上水下两部分.ROV式潜水平台型回收器,可在水下灵活运动,并可定向、定深.依靠电视跟踪技术和声纳定位技术实现回收器与水下机器人的对接.

一种测速多卜勒声纳的实现方法

本文介绍了多卜勒测速原理和测高原理并着重介绍了一种多卜勒测速声纳的实现方法及8098单片机在多卜勒测速声纳的应用。

微功耗海底地震仪的研制

Our motherland has large area of maritime space. Searching and developing ocean becomes more and more important. So Ocean Bottom Seismometer (OBS) as an absolutely necessary equipment can be used in many oceanic fields. OBS not only is an important instrument for discovering structure of lithosphere of ocean bottom, but also plays a main role of oceanic geophysical exploration. The paper introduces my relational work. The MCI micro-power broad frequency seismometer was developed independently. Its power dissipation is less than 300mW. It has some merits including miniature volumeN light mass and cheap price. It is an ideal device not only for the collection high-resolution natural seismic data, but also for the fields of seismic sounding and engineering seismology. Many new high technique were applied to develop this instrument including over-sampling A/D converter, high performance 32bit Micro Process Unit and Flash memory with smart-media interface. Base on the achievement, I have accomplished the showpiece of OBS, which is applied to the deepwater oil and gas geophysical exploration. Because of micro-power dissipation, the seismograph and the sonar releaser can be integrated into a sphere cabin. By this means, the instrument's frequency of resonance and frequency of couple are improved obviously. The data acquisition system of OBS is improved from MCI seismometer. The capacity of flash memory is enlarge from 1G bytes to 8G bytes. The advance MPU in data acquisition system is used to integrate other function modules such as sonar, GPS, compass and digital transmitter.

Redundant Sensors for Mobile Robot Navigation

Redundant sensors are needed on a mobile robot so that the accuracy with which it perceives its surroundings can be increased. Sonar and infrared sensors are used here in tandem, each compensating for deficiencies in the other. The robot combines the data from both sensors to build a representation which is more accurate than if either sensor were used alone. Another representation, the curvature primal sketch, is extracted from this perceived workspace and is used as the input to two path planning programs: one based on configuration space and one based on a generalized cone formulation of free space.

EXPERIMENTAL INVESTIGATION OF LINEAR BUBBLE DYNAMICS IN A VISCOELASTIC XANTHAN GEL

Oceanic bubble plumes caused by ship wakes or breaking waves disrupt sonar communi- cation because of the dramatic change in sound speed and attenuation in the bubbly fluid. Experiments in bubbly fluids have suffered from the inability to quantitatively characterize the fluid because of continuous air bubble motion. Conversely, single bubble experiments, where the bubble is trapped by a pressure field or stabilizing object, are limited in usable frequency range, apparatus complexity, or the invasive nature of the stabilizing object (wire, plate, etc.). Suspension of a bubble in a viscoelastic Xanthan gel allows acoustically forced oscilla- tions with negligible translation over a broad frequency band. Assuming only linear, radial motion, laser scattering from a bubble oscillating below, through, and above its resonance is measured. As the bubble dissolves in the gel, different bubble sizes are measured in the range 240 – 470 μm radius, corresponding to the frequency range 6 – 14 kHz. Equalization of the cell response in the raw data isolates the frequency response of the bubble. Compari- son to theory for a bubble in water shows good agreement between the predicted resonance frequency and damping, such that the bubble behaves as if it were oscillating in water.

Repeated mapping of reefs constructed by Sabellaria spinulosa Leuckart 1849 at an offshore wind farm site

Sabellaria spinulosa reefs are considered to be sensitive and of high conservation status. This article evaluates the feasibility of using remote sensing technology to delineate S. spinulosa reefs. S. spinulosa reef habitats associated with the Thanet Offshore Windfarm site were mapped using high resolution sidescan sonar (410 kHz) and multibeam echo sounder (<1 m2) data in 2005 (baseline), 2007 (pre-construction baseline) and 2012 (post-construction). The S. spinulosa reefs were identified in the acoustic data as areas of distinct irregular texturing. Maps created using acoustic data were validated using quantitative measures of reef quality, namely tube density (as a proxy for the density of live S. spinulosa), percentage cover of S. spinulosa structures (both living and dead) and associated macrofauna derived from seabed images taken across the development site. Statistically significant differences were observed in all physical measures of S. spinulosa as well the number (S) and diversity (H׳) of associated species, derived from seabed images classified according to the presence or absence of reef, validating the use of high resolution sidescan sonar to map these important biogenic habitats. High precision mapping in the early stages allowed for the micro-siting of wind turbines in a way that caused minimal damage to S. spinulosa reefs during construction. These habitats have since recovered and expanded in extent. The surveys undertaken at the Thanet Offshore Windfarm site demonstrate the importance of repeat mapping for this emerging industry, allowing habitat enhancement to be attributed to the development whilst preventing background habitat degradation from being wrongly attributed to the development.

Multidimensional DSP Core Synthesis for FPGA

This paper, chosen as a best paper from the 2004 SAMOS Workshop on Computer Systems: describes a novel, efficient methodology for automatically creating embedded DSP computer systems. The novelty arises since now embedded electronic signal processing systems, such as radar or sonar, can be designed by anyone from the algorithm level, i.e. no low level system design experience is required, whilst still achieving low controllable implementation overheads and high real time performance. In the chosen design example, a bank of Normalised Lattice Filter (NLF) components is created which a four-fold reduction in the required processing resource with no performance decrease.

Rapid Implementation and Optimisation of DSP Systems on FPGA-Centric Hetrogeneous Platforms

This paper, chosen as a best paper from the 2005 SAMOS Workshop on Computer Systems: describes the for the first time the major Abhainn project for automated system level design of embedded signal processing systems. In particular, this describes four key novelties: novel algorithm modelling techniques for DSP systems, automated implementation realisation, algorithm transformation for system optimisation and automated inter-processor communication. This is applied to two complex systems: a radar and sonar system. In both cases technology which allows non-experts to automatically create low-overhead, high performance embedded signal processing systems is exhibited.

Assessing the Impact of Shipping Vessel Noise on Humpback Whales

The ocean is a hub of noise. Bioacoustic noise, noise from precipitation and wind, and noise from oceanic shelf slides and other geologic processes have occurred consistently as marine species have evolved over time. However, with the discovery of oceanic oil and gas reserves, submarine systems, ship propulsion and the emergence of global trade, anthropogenic sources of sound have added significant quantities of sound to the oceanic system. Shipping has been found to be the largest input of low-frequency anthropogenic noise and Humpback Whales (Megaptera novaengliae), known to be the most vocal marine species, have an auditory sensitivity that falls within the range of frequencies emitted by shipping vessels. As Humpback Whales are heavily dependent on vocalizations, for reasons relatively unconfirmed, a better understanding of why they sing and how their communication is being impacted by vessel noise is critical. Evaluating existing literature both on Humpback behavior and communication, the mechanics of their communication, sound emissions from modern ships, oceanic sound transmission, and studies regarding Humpback's exposure to other sources of low-frequency anthropogenic noise, it is clear that more research is needed to draw any causational conclusions between vessel noise and detrimental impacts on Humpback Whales. With a projected increase in global consumption and vessel traffic, there is an urgent need for further research exploring shipping noise impacts and behavioural alterations of Humpbacks. Existing research has shown changes in Humpback communication when exposed to low-frequency sonar noise, however few studies have been conducted on their communication when in close proximity to shipping vessels. In order for the impacts to be properly assessed, preliminary understanding of humpback communication, their auditory thresholds and more studies between vessel noise exposure and Humpback Whale behavior must be conducted.