深埋复杂车站智能导航系统研究与实现

深埋复杂车站中的定位导航面临定位信号缺失、人流密度高、车站空间复杂等问题.为实现快速、精准地实时定位与导航,文章以北京—张家口高速铁路某深埋复杂车站的多层空间为对象,搭建智能导航系统,根据导航需求对车站建筑信息模型(BIM,Building Information Modeling)进行格式转换和信息读取,导入至Uni...     

正面全宽碰撞中假人及安全带关系的研究与应用

通过对正面全宽碰撞中假人头部、颈部、胸部、臀部、大腿及安全带数据的分析,指出这些数据曲线间具有一定相关性,并分别建立起曲线x、x′的比对关系。对曲线x、x′比对关系的应用进行分析指出,在只有安全带作用阶段,曲线x、x′吻合,可进行试验数据真实性的校核;在安全气囊或转向盘作用阶段,曲线x、x′具有差异性,可进行安全带、安全气囊等作用效果的分析。     

卫星定位不停车收费中基于决策圈的路径识别方法

首次提出在复杂区域使用决策圈的方法进行地图匹配,并提出一种GPS地图匹配和设置决策圈结合的新的路段识别方法,用于解决高速公路卫星收费系统或车栽导航中复杂路段地图匹配不准确的问题.对常规地图匹配算法GPS由于精度难以匹配的路段区域设定决策圈,对决策圈内路段进行特殊匹配处理.在处理方法上利用预先采集到的路段上的准确点代替电...     

Low cost two dimension navigation using an augmented Kalman filter/Fast Orthogonal Search module for the integration of reduced inertial sensor system and Global Positioning System

Due to their complementary characteristics, Global Positioning System (GPS) is integrated with standalone navigation devices like odometers and inertial measurement units (IMU). Recently, intensive research has focused on utilizing Micro-Electro-Mechanical-System (MEMS) grade inertial sensors in the integration because of their low-cost. In this study, a low cost reduced inertial sensor system (RISS) is considered. It consists of a MEMS-grade gyroscope and the vehicle built-in odometer. The system works together with GPS to provide 2D navigation for land vehicles. With adequate accuracy, Kalman filter (KF) is the commonly used estimation technique to achieve the data fusion of GPS and inertial sensors in case of high-end IMUs. However, due to the inherent error characteristics of MEMS grade devices, MEMS-based RISS suffers from the non-stationary stochastic sensor errors and nonlinear inertial errors, which cannot be handled by KF and its linear error models. To overcome the problem, Fast Orthogonal Search (FOS), a nonlinear system identification technique, is suggested for modeling the higher order RISS errors. As a general-purpose numerical method, FOS algorithm has the ability to figure out the system nonlinearity efficiently with a tolerance of arbitrary stochastic system noise. Even using online short-term training data, this method is still able to build an accurate nonlinear model that predicts the system dynamics. Motivated by the above merits, an augmented KF/FOS module is proposed by cascading FOS algorithm to a traditional KF structure. By estimating and reducing both linear and nonlinear RISS errors, the proposed method is supposed to offer substantial enhancement on the positioning accuracy of MEMS-based RISS during GPS outages. In order to examine the effectiveness of the proposed technique, the KF/FOS module is applied on the low cost RISS together with GPS in a land vehicle for several road test trajectories. The performance of the proposed method is compared to KF-only solution, both assessed with respect to a reference offered by a high-end solution. The experimental results confirm that KF/FOS module outperforms KF-only method. The results also show the applicability of the proposed method for real-time vehicle applications.     

基于蚁群算法的自适应路径导航算法

针对时常发生和不断加剧的交通拥挤、堵塞等情况,研究一种动态的、自适应的导航算法,以达到对车辆进行合理有效的路径导航和路径规划的目的.这一算法是在蚁群算法的基础之上,辅以多因素综合评判的方式,改进蚁群算法的评判标准,构建动态导航模型.以该导航模型为基础,通过仿真实验进行求解,仿真实验中将路径宽度、通行时延等随机因素考虑在内并进行综合权衡,使得动态导航的结果具有现实中的指导意义.数据实例表明,该导航算法是可行的、有效的,具有良好的导航效果,可为实际的导航系统提供有力地决策支持.     

基于有限元的内燃机曲轴疲劳强度分析

内燃机曲轴轴颈的过渡圆角处是应力高度集中部位,是疲劳裂纹的最先形成位置,因此曲轴圆角是曲轴设计时需要重点关注的部位。文章采用NASTRAN软件对某发动机缸体进行模态缩减,利用EXCITE-PU软件进行动力学分析,再通过N-soft软件进行圆角的疲劳安全系数分析。结果表明,通过增加圆角半径的方式可以解决曲轴的断裂问题。     

渔船稳性研究

稳性是保证渔船安全的重要性能，本文讨论了世界主要稳性规范对渔船的要求，并结合对多艘国产渔船稳性校核结果，对渔船的稳性提出了一些看法。同时，用时域分析方法研究了气象衡准。     

利用冗余测量值对船舶导航系统的故障检测与识别

本文在论述了具有冗余测量值时检测量误差的逻辑比较法之后，讨论了具有对称配置的四个单自由度惯性敏感器（陀螺仪或加速度计）构成的冗金系统（简称4S系统）的最优配置和性能管理，利用动态解析余度法解决了4S系统的故障检测和识别，通过理论分析和计算机仿真证明是有效的。     

弯曲河道上桥梁通航净宽的计算方法探讨

在弯曲通航河流上修建桥梁,其通航净宽对船舶安全航行及桥梁结构安全具有重要的影响。利用水槽模型试验成果,结合已有研究结论和有关标准及规范,提出了弯曲通航河道桥区通航净宽的计算方法,供航道和桥梁设计参考。     

开敞水域中斜跨航槽水流的流速计算

通过理论分析,运用试验数据,对开敞水域航槽中心垂线平均流速变化规律进行探讨,同时给出了航槽中心垂线平均流速的计算公式。在表达式中,边坡采用了比以往幂函数更为合理的指数函数形式。最后,用水槽试验数据对所得公式进行必要的验证,计算值与实际值吻合较好。