强倾弱弯梁桥设计准则研究

多起梁桥倾覆事故显示，主梁发生横向倾覆而未发生强度破坏，说明独柱墩梁桥的抗倾覆承载力和抗弯承载力不匹配。为避免超载作用下梁桥发生非延性的倾覆破坏，提出了强倾弱弯设计准则，并推导了强倾弱弯的计算公式。以跨径分布、箱梁线重度和支座分布等为参数，给出了三跨连续梁超载系数的快速计算公式。进一步以江苏无锡312高架桥、哈尔滨三环路鸿福路段高架桥和湖州104高架桥为例，进行强倾弱弯设计准则分析和初步验证。结果表明：①车道荷载横向偏载、纵向满布是连续梁桥抗倾覆最不利的活载布置方案；②传统独柱墩梁桥难以满足强倾弱弯设计准则，无法保证强度破坏发生在倾覆破坏之前；③忽略支座尺寸、大转动效应以及桥梁实际抗弯承载力与设计抗弯承载力的差异，抗倾覆稳定系数应大于2.88才能实现强倾弱弯，而不是2018版《公路钢筋混凝土及预应力混凝土桥涵设计规范》中规定的2.5。     

低碳经济背景下我国新能源汽车产业发展的对策研究

近年来,在经济发展政策不断调整的背景下,"绿色发展"、"可持续发展"战略被深化到了社会各个产业中。并且从整个世界经济发展的角度来看,节能、环保已经成为了时代的主题。在汽车产业发展过程中,由于碳排放量比较多,所以对经济和环境产生了较大压力。为此,在今后工作中,相关工作人员应该充分认识到低碳经济背景所产生的影响。结合时代发展战略规划进行相应调整,从而更好地推动整个产业的快速发展。由此可见:研究低碳经济背景下我国新能源汽车产业发展的对策具有积极的社会意义。     

跨界互联:海南新能源汽车赋能低碳旅游产业

本文主要介绍了海南新能源汽车的发展现状,阐述了低碳旅游产业的内涵特征,从理论角度分析交通碳足迹对低碳旅游产业的影响因素,通过总结海南新能源汽车赋能低碳旅游产业的模式,引出产业融合的可持续性发展重要意义。     

北京机场线直线电机车辆基地设计创新与应用

研究目的：北京市轨道交通首都机场线是北京第一条采用直线电机车辆运营的轨道交通线，该工程需要设置北京市第一座全自动车辆维修基地。在用地面积狭小及没有以往实际经验可参考的情况下，需要充分研究车辆特点进行设计。研究结果：通过分析直线电机车辆特点及本线特点，进行建筑单体整合，充分发挥直线车辆的特性，多次论证、比选、研究并汲取了国外先进维修设计理念，提出了较合理的总体布局方案，节省了用地。大胆地采用了新技术和新的理念，制定了切实可行的检修模式，为全自动无人驾驶直线电机车辆在北京地区的广泛使用奠定了基础，积累了经验，节省了工程投资。     

城市发展与智能交通——城市让人们生活更美好,更有尊严

城市快速发展凸显了交通问题,结合北京交通发展现状,对产生交通拥堵的原因进行了解析,提出智能交通的思想,展望了智能交通的发展趋势,有关经验可供相关专业人员参考.     

Gyroscopic stabilisers for powered two-wheeled vehicles

ABSTRACT

This paper illustrates the potential of a gyroscopic stabiliser for the stabilisation of single-track vehicles, at low and high speed as well as during braking. Alternative systems are considered, including single and twin counter-rotating gyroscopes, spinning and precessing with respect to different axes, either freely (passive stabilisers) or in a controlled way (active stabilisers). A suitable mathematical model has been developed and stability has been investigated both by eigenvalue calculation and time domain simulations. It has been found that the most effective configuration is one where the gyroscope(s) spin with respect to an axis parallel to the wheels' spin axis and swing with respect to the vehicle yaw axis. Passive systems may effectively stabilise both weave and wobble at medium and high speed, but cannot stabilise the vehicle at low and zero speed. On the contrary, actively controlled gyroscopes are capable of stabilising the vehicle in its whole range of operating speed, as well as during braking. The alteration of the original vehicle handling characteristics is negligible when active counter-rotating gyroscopes are used, and still acceptable if a single gyroscope is adopted instead.     

Evaluation of automotive forward collision warning and collision avoidance algorithms

Collision warning/collision avoidance (CW/CA) systems target a major crash type and their development is a major thrust of the Intelligent Vehicle Initiative. They are a natural extension of adaptive cruise control systems already available on many car models. Many CW/CA algorithms have recently been proposed but the existing literature mainly focuses on algorithm development. Evaluations of these algorithms have been usually based on subjective ratings. The main contribution of this paper is the utilization of a naturalistic driving data set for the evaluation of CW/CA algorithms. We first collect manual driving data from the ICCFOT project, then process the data by Kalman smoothing, and finally identify ‘threatening’ and ‘safe’ data sets according to vehicle brake inputs and vehicle range behavior. Five CW/CA algorithms published in the literature are evaluated against the identified data sets. The performance of these algorithms is determined through a performance metric commonly used in signal detection and information retrieval under unbalanced data population.     

Modelling generalisation and power dissipation of flexible-wheel suspension concept for planetary surface vehicles

Flexible-wheel (FW) suspension concept has been regarded to be one of the novel technologies for future planetary surface vehicles (PSVs). This study develops generalised models for fundamental stiffness and damping properties and power consumption characteristics of the FW suspension with and without considering wheel-hub dimensions. Compliance rolling resistance (CRR) coefficient is also defined and derived for the FW suspension. Based on the generalised models and two dimensionless measures, suspension properties are analysed for two FW suspension configurations. The sensitivity analysis is performed to investigate the effects of the design parameters and operating conditions on the CRR and power consumption characteristic of the FW suspension. The modelling generalisation permits analyses of fundamental properties and power consumption characteristics of different FW suspension designs in a uniform and very convenient manner, which would serve as a theoretical foundation for the design of FW suspensions for future PSVs.     

基于车联网的汽车自动换道方法研究

为弥补现有汽车自动换道时未考虑周围车辆运动状态变化以及舒适性差和通行效率低等方面的不足,同时提出了在车联网条件下的汽车自动换道方法,主要包括动态轨迹的规划、前馈与反馈相结合的PQ跟踪控制策略两部分,开展Carsim和simulink联合仿真以及实车验证结果表明,与传统非动态自动换道方法相比,该方法能有效解决在换道过程中周围车辆车速变化及车辆突然闯入等情况的难题,明显提高了换道过程中的安全性,由数据分析可知在保证车辆舒适性、稳定性的同时,换道时间缩短了20%,有效提高了车辆换道效率。