蠕动爬行攻泥机构转向工作特性的有限元分析

针对用于沉船打捞的水下攻泥机器人蠕动爬行攻泥机构的结构与工作机理，建立了适当的有限元计算模型，进而通过弹塑性有限元计算，模拟了攻泥机构处于土中不同深度的工作情况，建立了攻泥机构前进位移V和转向角θ之间关系的通用公式。通过它可以实现对攻泥机构前进路线的规划与自动控制。     

Noncontact power supply for seafloor geodetic observing robot system

A new and effective seafloor geodetic observing robot network system, which consists of several submarine stations situated in regions susceptible to interplate earthquakes, has been proposed and is under construction in Japan. Each station, equipped with an autonomous underwater vehicle (AUV) dock, is connected to a land facility by cables providing power and communication. Near the AUV dock, three or four seafloor reference stations will be set up for geodetic observations. In this system, a noncontact power supply is required for a battery-driven AUV to conduct observations for extended durations. A small, intelligent, efficient, high-power noncontact feed system of 400 W capacity with an inverting efficiency of 77% in salt water has been developed. It has been shown to be effective in a water tank experiment in which the noncontact power supply automatically fed power to an AUV for 3 days.     

Methodology for kinematic cycle characterization of vehicles with fixed routes in urban areas

This paper analyses the driving cycles of a fleet of vehicles with predetermined urban itineraries. Most driving cycles developed for such type of vehicles do not properly address variability among itineraries. Here we develop a polygonal driving cycle that assesses each group of related routes, based on microscopic parameters. It measures the kinematic cycles of the routes traveled by the vehicle fleet, segments cycles into micro-cycles, and characterizes their properties, groups them into clusters with homogeneous kinematic characteristics within their specific micro-cycles, and constructs a standard cycle for each cluster. The process is used to study public bus operations in Madrid.     

Emergency steering control of autonomous vehicle for collision avoidance and stabilisation

ABSTRACT

Collision avoidance and stabilisation are two of the most crucial concerns when an autonomous vehicle finds itself in emergency situations, which usually occur in a short time horizon and require large actuator inputs, together with highly nonlinear tyre cornering response. In order to avoid collision while stabilising autonomous vehicle under dynamic driving situations at handling limits, this paper proposes a novel emergency steering control strategy based on hierarchical control architecture consisting of decision-making layer and motion control layer. In decision-making layer, a dynamic threat assessment model continuously evaluates the risk associated with collision and destabilisation, and a path planner based on kinematics and dynamics of vehicle system determines a collision-free path when it suddenly encounters emergency scenarios. In motion control layer, a lateral motion controller considering nonlinearity of tyre cornering response and unknown external disturbance is designed using tyre lateral force estimation-based backstepping sliding-mode control to track a collision-free path, and to ensure the robustness and stability of the closed-loop system. Both simulation and experiment results show that the proposed control scheme can effectively perform an emergency collision avoidance manoeuvre while maintaining the stability of autonomous vehicle in different running conditions.     

古代木质沉船整体打捞技术

首次提出了一种适用于古代木质沉船的整体打捞方案,并且通过"南海1号"古沉船整体打捞模型试验对此方案进行了验证。     

Dynamic response of a surface ship structure subjected to an underwater explosion bubble

Bubble load in a noncontact underwater explosion can cause the ship hull global response and local response. In current literature, the ship hull is usually simplified as a hull girder to analyze its global response. However, literature dealt with the local response of a 3-D surface ship hull subjected to an underwater bubble were limited. This investigation develops a procedure which couples the finite element method with doubly asymptotic approximation (DAA) method to study the problem of transient responses of a ship hull structure subjected to an underwater explosion bubble. Using a 3-D ship model as examples, the global and local responses of the ship model in vertical, transverse and longitudinal directions are performed in detail. The acceleration, velocity and displacement time histories are presented. The characteristics of both the global and local responses of the ship model are discussed. The numerical results show that besides global whipping response, the ship hull also sustains severe local responses in different directions subjected to underwater explosion bubble jetting, which should be taken into consideration.     

西气东输中卫黄河隧道设计与施工

西气东输中卫黄河隧道是国家能源战略西北通道的咽喉工程,是西气东输备用通道和西气东输二线管道的主要通道,隧道内管道最大输气能力为470亿m3/年。文章介绍了西气东输中卫黄河隧道的工程地质、水文地质概况,以及设计原则和施工方法,总结出了油气管道水下隧道工程的设计和施工特点。     

四元数在水下航行体运动建模中的应用

针对一类以控制力矩陀螺（CMG）为姿态控制执行机构的水下航行体,考虑到其大角度机动时姿态描述矩阵可能会出现奇异的问题,建立了与其相适应的运动模型.首先,通过引入四元数来建立运动学方程,并给出四元数与欧拉角之间的关系.随后,在建立动力学方程时,将水下航行体视为由水下航行体和CMG组成的多刚体系统,并使用四元数来代替动力学方程中的欧拉角项.最后,使用龙格库塔法对所建立的模型进行仿真.仿真结果表明,所建立的模型能有效避免使用欧拉角方法建立模型时所产生的奇异问题.     

水下隧道修复方案及安全性分析

文章基于某水下盾构隧道因涌砂招致破坏后进行修复并继续使用的工程实例,详细阐述了套管法修复施工方案的工艺流程,并通过三维有限元模型对套管法修复施工过程进行了安全性分析。结果表明:采用液压振动锤施作外套管时其冲击力对下方既有隧道的影响不大,但需要对该施工过程进行计算校核;隧道变形和应力最大值基本发生在隧道顶部开口处,需要注意加强结构受力分析和止水措施。     

移动式水下观测网络试验节点研制

研制了一种低成本的试验节点作为移动式水下观测网络(MUSN)的有效技术验证平台。以一种现有的可在水面航行的小型运载器为基础,引入深度控制系统,得到了一种可以在浅水域完成可控运动的移动试验节点。针对MUSN节点间距较小的特点,提出了可抵偿偏差的移动定位算法,利用水声MODEM的测距信息实现节点在水下移动时较精确的定位。露天水域试验验证了该节点路径跟踪的性能,精度满足应用需要。该节点具备自主航行和节点间通信能力,可以用于MUSN协调控制技术的验证研究。