基于ITS技术的汽车驾驶安全辅助系统

基于ITS技术的汽车驾驶安全辅助系统是提高道路交通安全的有效手段,本文介绍了清华大学汽车安全与节能国家重点实验室在此领域的研究与开发工作。在研究行驶环境感知和信息融合、驾驶员特性和安全距离模型、车辆运动控制及系统集成等关键技术的基础上,研制了汽车驾驶安全辅助系统试验平台和试验样车,实现了行车前撞预警、安全车距保持、智能车道保持等功能,并完成了相关试验分析与评价,为进一步开展基于ITS的汽车主动安全辅助技术的研究以及汽车驾驶辅助系统的产业化奠定了基础。     

汽车驱动桥的疲劳检测分析

通过对汽车驱动桥的疲劳寿命基本原理的分析，提出了基于高程块和惯性飞轮的疲劳寿命试验方法，并对该方法的实现进行了探索，开发了HCQ3．0试验系统。     

Which factors lead to driving errors? A structural equation model analysis through a driving simulator experiment

As driving error is a main contributory factor of road accidents, its causes and consequences are of great interest in the road safety decision making process. This paper investigates several factors (including driver distraction, driver characteristics and road environment) that affect overall driving error behaviour and estimates a new unobserved variable which underlines driving errors. This estimation is performed with data obtained from a driving simulation experiment in which 95 participants covering all ages were asked to drive under different types of distraction (no distraction, conversation with passenger, cell phone use) in rural and urban road environment, as well as in both low and high traffic conditions. Driving error was then modeled as a latent variable based on several individual driving simulator parameters. Subsequently, the impact of several risk factors such as distraction, driver characteristics as well as road environment on driving error were estimated directly. The results of this complex model reveal that the impact of driver characteristics and area type are the only statistically significant factors affecting the probability of driving errors. Interestingly, neither conversing with a passenger nor talking on the cell phone have a statistically significant impact on driving error behaviour which highlights the importance of the present analysis and more specifically the development of a measure that represents overall driving error behaviour instead of individual driving errors variables.     

电动汽车维护周期现状及确定方法探究

本文分别分析了6个电动乘用车车型和商用车车型的维护周期,得到纯电动乘用车(小客车)的平均维护周期间隔为1.2万公里或8个月,纯电动商用车平均维护里程区间为6000~51000km;分析了5种国内动力电池品牌的维护周期设置,动力电池企业给出的维护周期多数按照三级间隔划分,其平均间隔为1个月、4个月和10个月。总结了现行维护周期制定优化方法,并结合传统燃油汽车维护周期优化数学模型,探索性提出了适用于电动汽车维护周期的优化改进路径。研究结论对指导道路运输经营者科学制定维护周期、开展车辆维护工作具有参考意义。     

Construction Techniques for the Small-radius Curved Shield Tunnels in Water-rich Fractured Stratum with High Pressure北大核心CSCD

A variety of construction problems, such as bad cutting effects of cutters, unreasonable boring parame- ters and blowout, are often encountered during shield tunnelling under unfavorable geological conditions. Aimed at these construction difficulties of high pressure, abundant underground water, fractured rock stratum, long distance and small-radius curves of Fuzhou metro, the mechanical behaviors of cutting tools were analyzed through theoreti- cal calculations of cutter cutting force, then the reasonable cutter configuration, tunneling parameters and the proper time for cutter replacement were presented. Some measures, such as screw conveyor renovation, mucking control and lowering of groundwater, were adopted for controlling blowout based on practice. The stability of excavation face was analyzed by numerical simulation, and the measures for shield boring and posture control in the long distance and small radius curved tunnels were summarized. The conclusions are as follows: 1) when shield machine is driven in fractured stratum, the effect of lateral impact force produced by spalling rock on cutter will be very large and rein- forcement is needed for cutter; 2) cutter replacement should be taken at proper time based on muck samples in con- ditions of increasing of total shield thrust by 4 000-7 000 kN, cutter torque by 1 000-1 500 kN•m and driving speed smaller than 10 mm/min; 3) adopting screw conveyor device with innovative anti-blowout devices and control measures for ground precipitation and mucking, it controls blowout effectively; 4) the maximum axis offset and the height offset of segment meet the requirements of shield construction specifications during shield construction of long distance small-radius curved tunnel. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

基于车联网的用户汽车使用测量与应用

用户实际用车数据是汽车产品设计的重要基础,同时也是制定汽车系统、零部件设计标准,产品验证规范开发和评价指标的基础.汽车在联网环境中的大量信息,对于挖掘和分析汽车用户驾驶的特征,具有不可替换的意义和价值.通过对车辆加减速、油耗等行驶数据的挖掘,有助于分析用户的驾驶风格、行为和车辆工作情况,为整车厂设计和研发提供了客观用户...     

驾驶分心检测方法综述

道路交通事故已经成为世界人民非自然死亡的主要原因,有学者认为90％的交通事故与驾驶员自身因素关联,而其中又有超过50％与驾驶分心相关.为了对驾驶员分心进行识别以及为下一步的分心预警干预提供结果判断,文章介绍了常见的驾驶分心检测与识别方法,包括人脸识别方法,眼睛瞳孔位置识别以及基于驾驶员生理信号(EEG)的分心监测方法....     

Creating models of road sections and their use in driving dynamics simulations

The paper describes a system for measuring road section parameters in a way that the results can be used in driving dynamics simulations. The system consists of sensorics and a data acquisition subsystem supported by software for generating 3D road section geometrical models. These models are then used as driving surfaces in dynamics simulation packages to investigate and analyse different aspects of road design and its role in traffic accident analysis, reconstruction and prevention. The paper presents examples of measurements, road section modelling and simulation results, obtained by means of different software simulation tools. It discusses possibilities of further development and improvement of the system.     

Life cycle strategies of epipelagic copepods in the Southern Ocean

Twelve epipelagic copepod species were reviewed to compare their adaptations to the short primary production season and low temperatures which characterise the Southern Ocean. The species show a spectrum of adaptations, but three broad life cycle strategies were defined: (1) herbivorous in summer, a short reproductive period and winter diapause at depth (Calanoides acutus and possibly Ctenocalanus citer); (2) predominantly omnivorous/detritivorous diet, an extended period of feeding, growth and reproduction and less reliance on diapause at depth (Metridia gerlachei, Calanus propinquus, Calanus simillimus, Oithona similis, Microcalanus pygmaeus, and possibly Oncaea curvata and Oithona frigida); (3) overwintering and feeding within sea ice as early nauplii or copepodids (Stephos longipes and Paralabidocera antarctica). The large species Rhincalanus gigas appears to be intermediate between strategies (1) and (2). Contrasting species from groups (1) and (2), namely C. acutus and O. similis, were selected for more detailed comparison. For C. acutus, maximum (probably food saturated) feeding and egg production rates are well below equivalent values for Calanus spp. at lower latitudes. Likewise, summer growth and moulting rates are slower, and the growth season of this herbivore is only 2–4 months. Therefore, both the low summer temperatures and short primary production season seem to dictate a long (1 year) life cycle for C. acutus. A collation of data on O. similis revealed that its abundance increases about tenfold from the Antarctic shelf northwards to the Polar Frontal Zone, where abundances are similar to those in temperate and tropical shelf seas. In contrast to C. acutus, O. similis appears to remain in the epipelagic and reproduce there year-round, although the food sources which sustain this are still uncertain.