Flexible long range planning using low cost information

Contemporary transport planning requires a flexible modelling approach which can be used to monitor the implementation of a long term plan checking regularly its short term performance with easily available data; the original model is periodically updated using low cost information and this allows the evaluation of the changes to the plan which may be required. Such an approach requires models suited to regular updating and to the use of data from different sources. Models to update trip matrices from traffic counts have been available for some time; however, the estimation and/or updating of other model stages with low cost data has escaped analytical treatment. The paper discusses this idea and formulates the updating problem for an example involving a joint destination/mode choice model under various assumptions about the nature of the available data. Analytical solutions are proposed as well as some general conclusions.requests for offprints     

Efficient multiple model particle filtering for joint traffic state estimation and incident detection

This article proposes an efficient multiple model particle filter (EMMPF) to solve the problems of traffic state estimation and incident detection, which requires significantly less computation time compared to existing multiple model nonlinear filters. To incorporate the on ramps and off ramps on the highway, junction solvers for a traffic flow model with incident dynamics are developed. The effectiveness of the proposed EMMPF is assessed using a benchmark hybrid state estimation problem, and using synthetic traffic data generated by a micro-simulation software. Then, the traffic estimation framework is implemented using field data collected on Interstate 880 in California. The results show the EMMPF is capable of estimating the traffic state and detecting incidents and requires an order of magnitude less computation time compared to existing algorithms, especially when the hybrid system has a large number of rare models.     

新能源汽车电池管理方法综述

电池管理系统作为电动汽车的重要组成部分,其中准确估测荷电状态(SOC)和电池均衡管理是电池管理系统的核心功能,也是优化系统能量管理,提高动力电池的使用效率,延长电池使用寿命的关键,对电池的储能至关重要。详细介绍主要SOC的估测方法和电池均衡管理方法,并对其优劣性进行分析与阐述,通过文献综述与对比分析为电池组在使用时提出理论依据与维护措施,为未来的研究提供便捷研究方法。     

基于工作电压的动力电池剩余容量动态估算

以单体蓄电池为研究对象，为解决电动汽车动力电池在工作状态下的剩余容量（SOC）进行实时估算的难题，提出了一种新的动力电池剩余容量估算方法。通过外接一个处于工作状态下电池周期性的恒定电流负载，测得一系列的电池工作电压，这些工作电压采用阶段斜率的计算方法求电池该时刻的剩余时间，从而推算出电池的SOC。证明了动态工作点折算到静态工作点的可行性。该方法的相对误差最大不超过7％，通过软件可实施对温度、老化等因素的补偿。误差分析结果表明，该方法误差小，测量精度高。     

A Novel Approach to Vehicle Dynamics using the Theory of a Cosserat Point and its Application to Collision Analyses of Platooning Vehicles

A fully three-dimensional, computationally inexpensive vehicular model is presented. In contrast to traditional rigid body models, the vehicle's sprung mass is modeled as a (nonlinearly) deformable body. The formulation of the equations of motion is based on a continuum theory known as the theory of a Cosserat point. These equations largely preserve the relative simplicity of rigid body dynamics but incorporate deformable features. The ease of computer implementation permits the simultaneous simulation of vehicle and collision dynamics of multiple vehicles and highway objects. In this paper, the theory of a Cosserat point is summarized and its general application to vehicle and collision dynamics is illustrated. A three-dimensional collision algorithm is discussed with emphasis on small closing velocities (negligible residual crush, elastic rebound). The novel model is compared to standard procedures.     

To fully automate or not? Investigating demands and willingness to pay for autonomous vehicles based on automation levels

We review the literature on the motivators of consumers’ purchasing decisions regarding autonomous vehicles (AVs), focusing on environmental awareness, vehicle types, concerns about accidents, and merits. The willingness to buy (WTB) and willingness to pay (WTP) for AVs have been extensively studied. However, it is imperative to broaden the outlook and consolidate the existing knowledge base. Although the WTB and WTP for AVs have been studied, automation-level preferences have been underresearched. Based on more than 150,000 observations, we construct a choice model and calculate the WTP for each level of automation. Our results show that there is a disparity between people's WTB and WTP according to the automation level. In particular, we find that the coefficients regarding FAVs’ benefits and accidents significantly exceed those related to environmental concerns. Such results indicate that practical benefits and concerns influence AV demand and WTP to a greater extent than environmental awareness. Our model results indicate a disparity between WTB and WTP for AVs that mostly derives from the different types of environmental concerns, concerns about accidents, and perceived benefits from these automobiles. Our results urge policies according to which governments and companies closely examine consumers who exhibit WTB-WTP disparities. Issues relating to demand patterns, WTP, and a suitable policy framework are discussed.     

水声网络探测节点的一种运动目标参数估计算法

文章提出了一种水声网络探测节点的运动目标参数估计方法,即基于模型匹配原理的估计算法。给出了算法的原理和仿真分析。     

贺尔海枢纽立交方案比选

对贺尔海枢纽立交的方案比选设计进行了详细的介绍,希望能够为同类立交设计时提供技术借鉴。     

三种基于四元数模型的声矢量阵MUSIC算法

传统的基于长矢量模型的MUSIC算法没有充分利用矢量水听器各分量之间的正交特性,存在多目标分辨能力不足的缺点。针对这一情况,文中引入了四元数的概念,利用四元数能更好地描述矢量水听器各分量的正交结构这一优点,提出了三种基于四元数模型的二维声矢量阵方位估计算法:Q-VV算法、Q-PV算法和Q-PVV算法。与基于长矢量模型的MUSIC算法相比,新算法降低了协方差矩阵的维数,占用更少的内存空间。同时,由于利用了四元数强正交性约束的特点,新算法有好的单目标估计精度和多目标分辨能力。其中:Q-PV算法和Q-PVV算法利用了声压与振速的相干性,抗各向同性干扰的能力优于Q-VV算法。仿真实验证明了算法的有效性。     

拉索非线性振动参数敏感性分析及其频率区间估计

为准确把握拉索的动力学规律并指导工程应用,以拉索非线性振动理论(拉索自振频率的摄动法公式)为基础,以工程中常用的典型拉索为例,对拉索非线性自振频率的边界条件效应、参数敏感性以及区间估计方法进行研究.研究结果表明:拉索的边界条件效应随拉索长度、索力以及频率阶次的不同而不同;索力、线密度、弦长、抗弯刚度4个参数对于拉索各阶自振频率在影响程度、影响方式方面均存在显著差异,总体而言,自振频率偏差与索力和抗弯刚度2个参数的偏差成正比,与线密度和弦长2个参数的偏差成反比;根据拉索参数的概率统计特征能够获得拉索自振频率的区间估计.