Dual extended Kalman filter for vehicle state and parameter estimation

The article demonstrates the implementation of a model-based vehicle estimator, which can be used for combined estimation of vehicle states and parameters. The estimator is realised using the dual extended Kalman filter (DEKF) technique, which makes use of two Kalman filters running in parallel, thus 'splitting' the state and parameter estimation problems. Note that the two problems cannot be entirely separated due to their inherent interdependencies. This technique provides several advantages, such as the possibility to switch off the parameter estimator, once a sufficiently good set of estimates has been obtained. The estimator is based on a four-wheel vehicle model with four degrees of freedom, which accommodates the dominant modes only, and is designed to make use of several interchangeable tyre models. The paper demonstrates the appropriateness of the DEKF. Results to date indicate that this is an effective approach, which is considered to be of potential benefit to the automotive industry.     

Real-time traffic state estimation in urban corridors from heterogeneous data

In recent years, rapid advances in information technology have led to various data collection systems which are enriching the sources of empirical data for use in transport systems. Currently, traffic data are collected through various sensors including loop detectors, probe vehicles, cell-phones, Bluetooth, video cameras, remote sensing and public transport smart cards. It has been argued that combining the complementary information from multiple sources will generally result in better accuracy, increased robustness and reduced ambiguity. Despite the fact that there have been substantial advances in data assimilation techniques to reconstruct and predict the traffic state from multiple data sources, such methods are generally data-driven and do not fully utilize the power of traffic models. Furthermore, the existing methods are still limited to freeway networks and are not yet applicable in the urban context due to the enhanced complexity of the flow behavior. The main traffic phenomena on urban links are generally caused by the boundary conditions at intersections, un-signalized or signalized, at which the switching of the traffic lights and the turning maneuvers of the road users lead to shock-wave phenomena that propagate upstream of the intersections. This paper develops a new model-based methodology to build up a real-time traffic prediction model for arterial corridors using data from multiple sources, particularly from loop detectors and partial observations from Bluetooth and GPS devices.     

钢网面板加筋土挡墙动力特性试验的变形研究

基于泥质红砂岩粗粒土填料，采用MTS分别模拟地震荷载、交通荷载、加-卸载多循环荷载进行大尺寸模型试验，研究了钢网面板土工格栅加筋土挡墙在上述荷载作用下的动力特性，获得了不同峰值的水平地震激励下模型挡墙不同位置的水平动位移、竖向动位移峰值响应等实测值；采用不同频率、不同幅值的竖向交通荷载正交试验法，获得了该模型挡墙在重复荷载作用下的最大水平变形、最大沉降量及位置等动力特性参数值；通过7种荷载、21组加卸载循环试验，获得了加一卸载多循环荷载作用下的实测沉降值。试验结果表明：该加筋结构具有整体变形的特性，是优良的抗震结构，能承受抗震设防烈度为9度的地震荷载；同时该加筋结构具有良好的稳定性和抗破坏性，重复荷载的幅值和振动次数对结构动力变形特性的影响较大，而振动频率对变形特性的影响不显著；多循环荷载作用下该加筋结构能够明显减小不均匀沉降。过长的筋材并不能明显地改善加筋土挡墙的动力特性。     

基于FMECA故障分析的高速动车组制动系统RAMS研究

高速动车组制动系统RAMS管理能够保证车辆在其全寿命周期内达到其功能要求。文章以CRH2型高速动车组制动系统为对象建立了可靠性模型,利用FMECA方法,系统地分析了制动系统的故障模式影响及危害性,并将其可能的故障模式按严重程度分类,以便采取改进措施。     

格蕴涵代数的超滤

通过超滤构造超积是模型论中构造模型的一种重要方法。文中提出了格蕴涵代数中超滤的概念，研究了它与素滤子及有限交性的关系，并证明了它与极大真滤子的等价性，为进一步研究相应的超积理论打下了基础。     

无碰撞区准同步跳频通信系统多址干扰性能分析

基于跳频通信边缘效应的多址干扰性能分析模型,即四碰撞态Markov过程模型,本文分析了基于新型无碰撞区(NHZ)跳频序列的准同步跳频通信系统用户干扰性能。当准同步跳频系统组网时工作在NHZ跳频序列集的无碰撞区内时,用户的载波频率表现为无碰撞状态;而在无碰撞区边缘的碰撞状态则可视具体情况分为无碰撞或左碰撞或右碰撞状态;对于无碰撞区外的碰撞状态则为无碰撞或左碰撞或右碰撞或左右都碰撞的状态。据此本文分析了无碰撞区准同步跳频通信系统的载波频率碰撞状态序列的特性,并提出适合无碰撞区准同步跳频通信系统的用户干扰性能分析模型。分析和数值结果表明,采用NHZ跳频码的准同步跳频通信系统的多址干扰性能优于采用随机跳频码的异步通信系统。     

CRH3动车组单车隧道压力波特性估算

采用国内研制的高速列车通过隧道时压力波计算程序,模拟了特定隧道条件下CRH3动车组单车隧道压力波的基本特性,给出了隧道内、车头车尾处的压力波分布情况,以及对应车内处3 s内最大压差值等随车速变化的规律。同时,比较了动车组在德国和我国隧道条件下压力波的异同点。     

考虑前后多车的网联自动驾驶车辆混流跟驰模型

随着中国新基建战略的提出及自动驾驶和网联通信技术的不断发展，网联自动驾驶车辆（CAV）、自动驾驶车辆（AV）和常规人驾车辆混行的交通流将在未来长时间存在。建立适用于网联自动驾驶车辆、自动驾驶车辆和常规人驾车辆3种类型车辆的混流跟驰模型，考虑多前后车车头间距、多前车速度差、加速度差、与主体车辆的相对距离等因素，并进行典型场景的数值仿真。刹车和起步过程的3种混流数值仿真结果显示，模型在几种典型混行场景下均具有可行性，车辆的加速度和速度变化更为平缓。不同CAV比例下的数值仿真结果显示，车队中CAV比例越高，车队整体恢复至平稳状态的时间越短，波动幅度越小。CAV均质流数值仿真结果表明，与MHVAD模型相比，该模型不稳定区域减小33.8%，所控制的车队速度波动幅度减小14%。CAV与AV混流的数值仿真结果显示，与PATH实验室模型相比，由该模型控制的车队加速度进入相对稳定状态提前5.5 s。该模型可用于不同车辆均质流及3种车辆混行的队列控制，在目前开展混行实车试验困难的情况下，也可应用该模型进行混行跟驰仿真，从而为混行交通流的道路交通管理及基础设施布设提供理论依据和模型支持。     

Cost-time Minimization in a Transportation Problem with Fuzzy Parameters: A Case Study

In real world applications the supply, the demand and the transportation cost per unit of the quantities in a transportation problem are hardly specified precisely because of the changing economic and environmental conditions. It is also important that the time required for transportation should be minimum. In this paper a method has been proposed for the minimization of transportation cost as well as time of transportation when the demand, supply and transportation cost per unit of the quantities are fuzzy. The problem is modeled as multi objective linear programming problem with imprecise parameters. Fuzzy parametric programming has been used to handle impreciseness and the resulting multi objective problem has been solved by prioritized goal programming approach. A case study has been made using the proposed approach.     

浅水沉管船的锚泊定位系统设计

浅水锚泊系统的设计增加了诸多挑战,恶劣的环境使船舶具有较大的低频漂移运动,同时锚泊系统需要有足够的恢复力特性。文章针对深中通道沉管船,基于三维势流理论,在时域下对安装船和沉管系统进行分析,设计出合适的锚泊系统,并验证了锚泊系统设计的安全性。同时为以后类似系统的设计提供借鉴。