双断级滑行艇纵向运动稳定性的一种校核方法

目前双断级滑行艇纵向运动稳定性的理论计算方法还不成熟,推荐一种校核其纵向运动稳定性的实用方法,即利用模型试验得到纵向运动时而稳定时而不稳定的临界点组合,再运用最小二乘法拟合试验中得到的若干临界点得出双断级滑行艇纵向运动稳定性界限。用通过模型试验得到的纵向运动稳定性界限校核高速双断级滑行艇纵向运动稳定性能够获得比较准确的结果     

大连港成品油码头续建工程设计中一些问题的探讨

大连港成品油码头续建工程是外海开敞式油码头工程研究中的一个很好实例。分析和探讨了设计中的平面布置、码头结构型式及环境问题。     

面向弱势道路使用者的多目标运动轨迹预测方法

针对复杂行驶环境下弱势道路使用者（VRU）多目标轨迹预测方法存在的预测精度不足和预测性能不稳定的问题，提出一种基于历史序列信息的面向VRU的多目标轨迹预测方法（Vulnerable Road User Trajectory Predictor， VRU_TP）。首先，为了解决预测精度不足的难题，该轨迹预测方法框架融合时空的多维运动状态特征和多维外观语义特征因子，同时基于外观特征综合考虑目标的运动意图，提取多线索的轨迹预测因子作为各个VRU目标历史轨迹的编码输入。其次，为了克服现有方法预测性能不稳定的难题，在序列到序列的编解码器方法（Seq2Seq Encoder-decoder）的基础上，从网络结构设计和网络优化策略等方面提出适用于VRU轨迹预测的门循环神经网络（GRU）。该网络融合设计的plelu6激活函数，能基于历史的序列信息映射学习未来的轨迹信息，用来提高编解码器对未来轨迹的解码能力。最后，为了验证时空多元轨迹线索和门循环神经网络优化方法的有效性和实用性，在已公开的MOT16数据库和提出的VRU-Track数据库上，采用在图像空间上通用的归一化平均位置偏移（NADE）、平均重叠率分值（AOS）评价指标以及平均成功率（ASR）和成功率曲线（Success Plot）评价指标，并进行试验验证。研究结果表明：在MOT16划分的验证集中，相比于基准方法，NADE下降了19.4%，ASR提高了22.6%；在VRU-Track数据库测试集中，NADE下降了23.0%，AOS提高了17.1%，ASR提高了16.5%；提出的VRU_TP方法减少了预测值与真值之间的位置偏移，增加了预测值与真值的重叠率，提升了各类VRU目标轨迹预测的性能，而验证了该方法的有效性。     

Glacial ice impacts: Part I: Wave-driven motion and small glacial ice feature impacts

Glacial ice features in the northern and central Barents Sea may threaten ships and offshore structures. Particularly, small glacial ice features, which are difficult to detect and manage by concurrent technologies, are of concern. Additionally, small glacial ice features are more susceptible to wave-driven oscillatory motions, which increases their pre-impact kinetic energy and may damage ships and offshore structures. This paper is part of three related papers. An initial paper (Monteban et al., 2020) studied glacial ice features’ drift, size distribution and encounter frequencies with an offshore structure in the Barents Sea. The following two papers (Paper I and Paper II) further performed glacial ice impact studies, including impact motion analysis (Paper I) and structural damage assessment (Paper II). This paper (Paper I) studies the wave-driven motion of small glacial ice features and their subsequent impact with a given offshore structure. The aim here is to develop a numerical model that is capable of efficiently calculating the relative motion between the ice feature and structure and to sample a sufficient amount of impact events from which statistical information can be obtained. The statistical information entails the distributions of the impact location and associated impact velocities. Given the distributions of the impact velocities at different locations, we can quantify the kinetic energy for related impact scenarios for a further structural damage assessment in Paper II (Yu et al., 2020).In Paper I, a numerical model that separately calculates the wave-driven oscillatory motion and the mean drift motion of small glacial ice features is proposed, implemented and validated. Practical and fit-for-purpose hydrodynamic simplifications are made to simulate and sample sufficient impact events. The numerical model has been favourably validated against existing numerical results and experimental data. A case study is presented where a 10 m wide glacial ice feature is drifting under the influence of surface waves towards an offshore structure. The case study shows that if an impact happens, the overall impact location and impact velocity can be best fitted by the Normal and Weibull distributions, respectively. Additionally, the impact velocity increases with impact height. Moreover, the impact velocity increases and the impact range is more dispersed in a higher sea state. It is also important to notice that the approaches and methods proposed in this paper adhere to and reflect the general requirements stated in ISO19906 (2019) and NORSOK N-003 (2017) for estimating the design kinetic energy for glacial ice impacts.     

六自由度液压运动平台的分析与研究

针对目前舰船上运用广泛的多自由度运动结构设计周期长和成本高的问题,为了能更快更好地设计多自由度液压运动平台,采用虚拟仿真技术进行研究分析。以SolidWorks中建立六自由度液压平台模型为基础,通过SolidWorks与Matlab对该平台展开相应运动学仿真分析,对其负载指标、运动指标、机构运动姿态进行分析和计算,并在此基础上建立虚拟样机,验证该六自由度液压平台综合性能指标的正确性。最后通过对各指标进行误差分析,证明了设计模式的有效性,以此为依据研制出六自由度液压实验平台,为研制高精度运动模拟器打下良好的基础。     

一种新型水下平台的水平面运动控制

新型水下平台用于从水面布放设备至海底,或从海底回收至水面指定位置,其主要运动形式为垂向无动力下潜或上浮。为了克服垂向运动过程中来自水平方向洋流的扰动,需要对平台的水平位置和首向进行控制。针对平台水动力系数等模型参数难以计算,水平洋流未知、且水平推进系统布置特殊的特点,设计了不依赖于模型参数且具有全局稳定性的水平面运动控制系统,并应用Lagrange方法对推力分配进行了优化从而减小运动控制的总功耗。最后通过仿真对控制算法进行了验证。     

Calibration of response amplitude operators based on measurements of vessel motions and directional wave spectra

A vessel's response to waves is dependent on a large number of parameters, some of which are both frequency and direction dependent. To predict vessel response, these parameters are used to construct response amplitude operators (RAOs) that act as transfer functions between the directional wave spectra and the motion spectra of the vessel. In particular situations, however, vessel motions predicted using RAOs calculated with general-purpose radiation-diffraction codes and measured wave spectra are found to deviate from measured vessel responses. To address this problem, a methodology for calibrating RAOs based on measurements of the directional wave spectra and vessel motions is proposed. Use is made of a vector fitting method through which the frequency dependent hydrodynamic properties of the vessel can be approximated by a ratio of two polynomials, thus greatly reducing the number of parameters that need to be calibrated. The reduced set of parameters is subsequently related to previously identified causes of RAO inaccuracy in order to arrive at optimization algorithms for identifying more accurate RAOs from the measurements. It is shown that the RAOs can be improved with accuracy in situations where the discrepancies are caused by imprecise estimates for the vessel's radii of gyration, center of gravity, or viscous damping. When the discrepancies in the RAOs are related to the potential mass, damping and wave forces, however, the problem becomes highly non-convex and it is not possible to find a unique RAO that satisfies the data.     

信号平面布置图参数化设计软件的研究与开发

城市轨道交通正线室外信号平面布置图是编制后续信号系统图纸的基础。为提高信号平面布置图的设计效率和质量,调查分析全国各地城市轨道交通信号工程项目中平面布置图的不同设计要求,研究开发信号平面布置图参数化设计软件。该设计软件为设计人员提供简单易用的图形化交互式操作界面,无需安装AutoCAD环境即可实现DWG文件的创建和读写;通过参数化设计,将信号平面图的不同构成要素抽象定义为各种参数化模板,既可实现对不同的图形符号、设备编码规则等差异化设计要求的兼容,也为设计人员提供了快速设计信号平面布置图的设计构件;此外,其底层数据可支持电缆径路图、工程数量统计等扩展功能的开发。该软件已在多个城市轨道交通信号工程设计项目的应用,可满足不同设计要求,显著加快设计进度,减少人为差错。     

运用MICROSTATION-INROAD软件实现道路设计的方法研究

目前,在计算机辅助设计领域出现了许多公路选线设计软件,并在很多设计院所得到了不同程度的应用,工程设计与规划中基于地形图的三维虚拟技术越来越受到设计人员的重视.本文通过公路设计案例,对如何使用InRoads软件进行公路线路辅助设计进行了说明,其独特的组件设计能力,有效且准确的解决复杂的几何设计难题,可提供广泛的设计、分析...     

DSS—80型镗头回转精度的测试与评定

本文详细地介绍了使用双点法对DSS—80型镗头回转精度的现场测试;讨论了主轴径向误差运动园图象的分析处理和评定方法。测试系统简单,实验操作方便,数据可靠。这对高精度轴系的园度误差和表面粗糙度测试具有现实意