波浪环境下潜艇近水面操纵特性仿真分析

为研究波浪环境下潜艇近水面的操纵特性特别是垂直面的深度控制问题,基于海勒莫公式和势流理论分别计算近水面一阶波浪力和二阶波浪力,以模型潜艇为研究对象,将波浪力计算模型融入潜艇垂直面非线性操纵运动方程,进而对波浪环境下潜艇近水面操纵运动特性进行仿真研究,分析潜艇在不同有义波高、航速和初始潜深条件下的垂直面潜浮运动响应规律和...     

潜艇水下破损定深操纵方法仿真研究

分析自动舵垂直面定深控制系统及以均衡为目标的吹除方法,提出针对潜艇不同舱室破损升降舵的操纵方法及压载水舱的吹除方法,通过实例仿真验证提出的操纵方法的有效性。     

Impact of heavy vehicles on surrounding traffic characteristics

This work examines the impact of heavy vehicle movements on measured traffic characteristics in detail. Although the number of heavy vehicles within the traffic stream is only a small percentage, their impact is prominent. Heavy vehicles impose physical and psychological effects on surrounding traffic flow because of their length and size (physical) and acceleration/deceleration (operational) characteristics. The objective of this work is to investigate the differences in traffic characteristics in the vicinity of heavy vehicles and passenger cars. The analysis focuses on heavy traffic conditions (level of service E) using a trajectory data of highway I‐80 in California. The results show that larger front and rear space gaps exist for heavy vehicles compared with passenger cars. This may be because of the limitations in manoeuvrability of heavy vehicles and the safety concerns of the rear vehicle drivers, respectively. In addition, heavy vehicle drivers mainly keep a constant speed and do not change their speed frequently. This work also examines the impact of heavy vehicles on their surrounding traffic in terms of average travel time and number of lane changing manoeuvres using Advanced Interactive Microscopic Simulator for Urban and Non‐Urban Networks (AIMSUN) microscopic traffic simulation package. According to the results, the average travel time increases when proportion of heavy vehicles rises in each lane. To reflect the impact of heavy vehicles on average travel time, a term related to heavy vehicle percentage is introduced into two different travel time equations, Bureau of Public Roads and Akçelik's travel time equations. The results show that using an exclusive term for heavy vehicles can better estimate the travel times for more than 10%. Finally, number of passenger car lane changing manoeuvres per lane will be more frequent when more heavy vehicles exist in that lane. The influence of heavy vehicles on the number of passenger car lane changing is intensified in higher traffic densities and higher percentage of heavy vehicles. Large numbers of lane changing manoeuvres can increase the number of traffic accidents and potentially reduce traffic safety. The results show an increase of 5% in the likelihood of accidents, when percentage of heavy vehicles increases to 30% of total traffic. Copyright © 2014 John Wiley & Sons, Ltd.     

新型实船测试平台的研究

提出一种新型的船舶实船测试平台,对该平台的结构、传感器的选择和系统的集成给出了详细的阐述,并介绍了实船测试平台的用途。实船测试实例表明,该测试平台工作稳定可靠,性能良好。     

Formulation and interpretation of optimal braking and steering patterns towards autonomous safety-critical manoeuvres

ABSTRACT

Stability control of a vehicle in autonomous safety-critical at-the-limit manoeuvres is analysed from the perspective of lane keeping or lane changing, rather than that of yaw control as in traditional ESC systems. An optimal control formulation is developed, where the optimisation criterion is a linear combination of the initial and final velocity of the manoeuvre. Varying the interpolation parameter in this formulation turns out to result in an interesting family of optimal braking and steering patterns in stabilising manoeuvres. The two different strategies of optimal lane-keeping control and optimal yaw control are shown to be embedded in the formulation and result from the boundary values of the parameter. The results provide new insights and have the potential to be used for future safety systems that adapt the level of braking to the situation at hand, which is demonstrated through examples of how to exploit theresults.     

基于模糊PID方法的ROV操纵控制仿真

为应对复杂的作业工况和海洋环境,研究了水下中型作业遥控机器人(ROV)的操纵控制运动.文章分析了作业型ROV的操纵特性,根据其基本的定向、定高和定深的航行能力需求,基于模糊PID方法的控制原理,为其配置了精度高、响应快的控制系统,建立了4自由度操纵控制运动模型,对定向、定高等运动性能的操纵进行仿真研究,通过水池实验验证了该控制方法的有效性.     

山区公路纵坡段驾驶人脚操纵特征及驾驶负荷

为证实山区道路纵坡参数与驾驶人生理指标之间的相关性,明晰纵坡路段参数影响驾驶负荷的内在机制,在3条山区双车道公路上开展了小客车实车驾驶试验,采集道路纵坡参数、真实驾驶习惯条件下的驾驶人心电信号、加速踏板力和制动踏板力。基于实测数据,描述制动和加速踏板力幅值的分布特性,分析坡度值对踏板力的影响;探讨加速踏板力、制动踏板力与心率增长率H之间的关联度,并建立H与踏板力之间的回归模型,最终从体力和精神负担两方面揭示了纵坡路段驾驶负荷的形成机制。研究结果表明：制动踏板力的均值和特征分位值均高于加速踏板力,对应最高使用频率的制动踏板力幅值也高于加速踏板力,即下坡路段踩踏板操作的体力负荷更大;踏板力与H正相关,其中下坡制动踏板力与H之间的相关性更强,表明下坡路段尤其是陡坡路段的踏板操作更容易导致精神负担;当踏板力超过某幅值之后,部分驾驶人的H对踏板力的增加变得敏感;对纵坡单元各被试驾驶人的H和踏板力数据取均值,发现在消除驾驶人的个体差异之后,H踏板力的相关性变得更高。