电控空气悬架车辆自适应前照灯控制策略研究

为有效提高前照灯夜间照明效果,本文在充分考虑国标GB7258《机动车运行安全技术条件》基础上,根据车身高度、车速等信号变化,提出一种自适应前照灯系统(adaptive front-light system,AFS)的新型前照灯垂向控制策略,以合理调节其夜间照射角度。同时,采用Matlab/Simulink和Stateflow软件,建立前照灯垂向控制策略模型,并对车辆在加速工况和减速工况条件下进行仿真分析。仿真结果表明,在车辆高度变化及车辆加速情况下,所提出的控制策略模型可有效调节前照灯照射角度,提高驾乘安全性;在车辆高度变化及减速条件下,所提出的控制策略模型亦可实时有效地调节前照灯照射角度,改善驾乘人员夜间行驶安全性。该研究可有效提高电控空气悬架系统车辆夜间行车安全性。     

基于CAN总线的汽车智能前照灯系统设计浅析

基于CAN总线的汽车智能前照等系统,可以提高车辆夜间转弯行驶安全性,对比传统前照灯光系统来讲,其具有更高的利用效率,本文对系统设计要点进行了简单分析.     

车辆夜间驾驶辅助系统设计

本文针对车辆夜间驾驶过程中视线盲区或者会车过程中车灯对驾驶者的干扰所造成的安全隐患,提出一种近红外多波长自动切换车辆夜间驾驶辅助系统的设计方法.所设计的系统包括可变波长近红外照明系统、超焦距红外成像光学系统、波长自动转换系统、红外成像及信号处理系统、车辆电子控制单元(ECU)连接系统以及投影或屏幕显示与目标提示系统等.该系统利用辅助近红外光源提高道路的红外照明条件,并通过多个近红外照明和成像波长的自动切换实现近红外清晰成像,避免相对行驶车辆会车时光线的相互干扰,提高车辆驾驶的安全性.针对系统主要要求,设计了中心波长850 nm,峰值透过率高于90%,带宽小于20 nm的带通滤光片;确定了满足180 m照明距离所需要的发光二极管的总功率为30 W.     

车辆随动转向大灯将成为标配

车辆的普通大灯具有固定的照射范围．当汽车在夜间弯道上转弯时．无法调节照明角度．常常会在弯道内侧出现“盲区”。随动转向大灯能够不断对大灯进行动态调节．保持与汽车当前的行驶方向一致．确保驾驶员拥有最佳的可见度。     

驾驶员夜间对过街行人的视认规律

为了给合理确定人行横道处的夜间最高限速值与道路照明指标提供理论依据,保证过街行人夜间出行安全,开展了驾驶员夜间对过街行人的视认距离随行驶车速及路灯平均照度的变化规律研究.针对6处人行横道单个静止并着深色衣服的过街行人,采集了8名驾驶员对其夜间视认距离的数据.采用回归分析的方法,构建了不同照度条件下的驾驶员夜间视认距离与行驶车速关系模型、不同车速等级下的驾驶员夜间视认距离与平均照度关系模型,以及驾驶员夜间视认距离-行驶车速-平均照度关系模型.结果表明,驾驶员夜间对过街行人的视认距离随行驶车速的提高而降低,二者呈负线性相关;随平均照度的提高而增加,二者呈正对数相关.     

基于双功率流差速转向履带车辆关键参数研究

为了适应复杂环境和非结构化地形,提出一种具有平衡摇臂的双功率流差速转向的履带车辆动力底盘。该履带车能够实现调节地隙、自适应路面、障碍物跨越、灵活的姿态调节和稳定的姿态保持以及轮履复合的设计要求。本文确定了具有差速转向机构的履带车辆的总体构型方案,根据驱动力和行驶阻力的平衡建立了行驶模型,根据履带车辆爬坡角度和爬坡速度,建立了爬坡时所需功率模型,以此为基础,确定了移动机器人爬坡时驱动电机最大功率与最大爬坡度和爬坡时的车速之间的关系,分析和计算了履带车辆直线行驶电机、转向行驶电机、摆臂调节电机的功率,推导出了转向时内外侧履带所受的转向阻力矩,并确定了车辆对质心总转向阻力矩。该研究成果能为履带车辆的样机研制和试验提供了理论依据和研究手段。     

城市道路人行横道处照明指标的确定

为了合理确定城市道路人行横道处的照明指标,保证驾驶人对过街行人的有效视认,进行了驾驶人夜间视认距离试验研究。分析了过街行人数量、状态(静止或运动)及衣服颜色对驾驶人夜间识别距离的影响,以及不同车速条件下驾驶人夜间视认距离随平均照度的变化规律,构建了驾驶人夜间视认距离-平均照度-车速关系模型。基于驾驶人夜间视认距离与反应制动距离间的安全行驶判别条件,提出了城市道路人行横道处平均照度的计算方法,并给出了实际案例。研究结果表明:当单个过街行人静止且衣服颜色较深时,驾驶人夜间对其进行视认最为困难;驾驶人夜间视认距离与平均照度呈正对数相关,与行驶速度呈负线性相关。     

冰雪路面公路平曲线路段限速仿真

为了提高冬季北方地区公路的行车安全,减少交通事故,对冰雪路面平曲线路段展开限速研究．应用车辆运动学理论,考虑驾驶员在弯道驾驶车辆的特点,分析车辆在冰雪路面转弯行驶特性,建立车辆在平曲线路段行驶时的运动学模型．选择载货汽车和轿车两种车型,松软雪路面、压实雪路面和冰路面3种路况,分别建立车辆行驶速度与平曲线设计指标的关系模型．选取6％、8％和10％ 3种超高值的平曲线路段,利用Matlab仿真技术对车辆限速模型进行求解,并对车速与圆曲线半径及超高的相关性进行分析．以此为基础,提出车辆在松软雪路面、压实雪路面和冰路面3种路况下,不同圆曲线半径的相应安全行驶速度,为科学合理地确定冰雪路面平曲线路段的车辆限速值提供理论依据．     

履带车辆自动变速系统的智能控制方法

分析了履带车辆复杂多变的行驶工况,针对车辆行驶状态参数、路面状况和驾驶员操纵信息的人-车-路闭环系统,确定了履带车辆智能换挡控制的主要原则.运用智能控制理论,提出了履带车辆自动变速系统实现模糊神经网络控制的总体方案和技术路线,系统可自动适应复杂多变的车内外行驶情况,以提高履带车辆的动力性和越野机动性.     

自适应积分终端滑模的自主车辆路径跟踪控制

为了实现自主车辆在复杂行驶环境下有效的路径跟踪功能,车辆必须配备一个拥有鲁棒性的控制系统,因此提出了一种自适应积分终端滑模控制策略。首先,采用了一个二自由度的车辆动力学模型以及一个简化运动学模型,用来描述车辆行驶时的横向动力学和路径跟踪特性;其次,设计了一种自适应积分终端滑模控制器,并利用李雅普诺夫稳定性判据证明了该控制系统的稳定性;最后,利用Matlab-Carsim联合仿真平台,以不同的车速分别在冰雪路面和干沥青路面上进行仿真测试,验证了所设计控制器的性能。仿真结果表明:当车辆行驶在不同的路面和速度工况下时,相较于传统滑模控制以及非奇异终端滑模控制,自适应积分终端滑模控制不仅拥有更高的控制精度,同时具有更强的鲁棒性能。     

线控四轮独立驱动轮毂电机电动车集成控制

从提高车辆操纵稳定性的角度,基于模型预测控制理论对线控四轮独立驱动轮毂电机电动车进行主动转向(AFS)、直接横摆力矩(DYC)和主动悬架(AS)的集成控制研究。采用分层集成控制结构,设计了模型预测控制器。研究了驱动力矩控制分配规则和AS控制方法,实现了AFS/DYC的水平集成控制和AFS/DYC/AS的全局集成控制,并通过仿真实验对算法进行了验证。仿真结果表明:集成控制算法能够实现车辆有效跟踪期望值,提高车辆极限工况的稳定性和主动安全性。     

Synthesis and Characterization of Lignin Grafting Modification-based Aliphatic Superplasticizer

Lignin as the main component of black liquor is generally employed to modify aliphatic superplasticizer(AFS). However, the modification effect is hard to evaluate correctly due to the uncertain molecular structure of lignin and the disturbance from the complexity of black liquor compositions. In this paper, the purified lignin via acid precipitation from straw black liquor is used to modify AFS. The modified AFS named as LAFS for short presents lower molecular mass than AFS. It is assumed that it is due to the single active site of guaiacol segments in lignin by which lignin graft modifies AFS in virtue of methylolation reaction. In order to verify this assumption, guaiacol and dihydro eugenol as the typical segments of lignin macromolecule were selected, respectively, as the simplified model compounds of lignin to modify AFS, and corresponding products are abbreviated in GAFS and DAFS. Both GAFS and DAFS show the lower molecular mass than unmodified AFS. FTIR and TG-DTG analyses prove that lignin is successfully grafted onto AFS. The graft modification of lignin results in a decrease in electrostatic epulsion, but an enhanced steric hindrance. Therefore, although the replacement rate of lignin in LAFS was about 23.3%, the dispersion performance was only slightly affected.     

Path planning and stability control of collision avoidance system based on active front steering

Vehicle collision avoidance system is a kind of auxiliary driving system based on vehicle active safety,which can assist the driver to take the initiative to avoid obstacles under certain conditions,so as to effectively improve the driving safety of vehicle.This paper presents a collision avoidance system for an autonomous vehicle based on an active front steering,which mainly consists of a path planner and a robust tracking controller.A path planner is designed based on polynomial parameterization optimized by simulated annealing algorithm,which plans an evasive trajectory to bypass the obstacle and avoid crashes.The dynamic models of the AFS system,vehicle as well as the driver model are established,and based on these,a robust tracking controller is proposed,which controls the system to resist external disturbances and work in accordance with the planning trajectory.The proposed collision avoidance system is testified through CarSim and Simulink combined simulation platform.The simulation results show that it can effectively track the planning trajectory,and improve the steering stability and anti-interference performance of the vehicle.     

高速公路长隧道夜间出口照明优化研究

我国现行隧道通风照明标准中,关于高速公路长隧道夜间出口段照明设计存在缺失,而上述问题对于行车安全和节能减排具有重要意义.为使高速公路长隧道出口段照明适合驾驶人需求,选用11名驾驶人进行夜间隧道实际行车试验.以眼动仪记录驾驶人瞳孔面积实时变化参数,照度计测量不同点的环境照度,非接触式五轮仪测量行车速度.运用多元曲面回归分析方法,获得瞳孔面积随照度和适应时间变化的规律,并建立量化模型.研究表明：现有隧道夜间出口段照度过高,与驾驶人实际需求差异大,造成驾驶人严重的暗适应问题;该段的照度值应按驾驶人需求进行优化,逐渐降低洞内照度并在出口外增设照度逐渐降低的照明设施.计算列举了出口段不同位置具体照度值,以减弱暗适应对行车的影响.     

Multi-objective optimization of active steering system with force and displacement coupled control

A novel active steering system with force and displacement coupled control (the novel AFS system) was introduced, which has functions of both the active steering and electric power steering. Based on the model of the novel AFS system and the vehicle three-degree of freedom system, the concept and quantitative formulas of the novel AFS system steering performance were proposed. The steering road feel and steering portability were set as the optimizing targets with the steering stability and steering portability as the constraint conditions. According to the features of constrained optimization of multi-variable function, a multi-variable genetic algorithm for the system parameter optimization was designed. The simulation results show that based on parametric optimization of the multi-objective genetic algorithm, the novel AFS system can improve the steering road feel, steering portability and steering stability, thus the optimization method can provide a theoretical basis for the design and optimization of the novel AFS system.     

A Novel Method to Fabricate Steel-Al Foam Sandwich Panel with Metallic Bonding

Al foam sandwich panel(AFS) with metallic bonding was fabricated by foaming a hotpressed three-layer composite with two steel facesheets and a melt route precursor as core. The melt route precursor was fabricated by dispersing undecomposed blowing agent into molten Al, followed by solidification. Microstructures of the joints during fabrication process were analyzed by scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). Static three-point bending was conducted to evaluate joint quality of the AFS. It was found that a primary bonding was achieved by hot-pressing and significant diffusion layer of Fe-Al intermetallic compounds was sustained between steel and Al foam core by foaming. Damage modes of the AFS under three-point bending were dominated by indentation, plastic hinges, core shear and crack. Delamination between steel and foam was absent, implying that reliable metallic bonding was achieved. This method allows for producing large-scale AFS with steel facesheets.     

对中小城市夜光环境的绿色思维与建议

分析了中、小城市夜光环境目前存在的不足,揭示了产生这种不足的原因,诠释了夜光环境照明的绿色思维理念,阐明了绿色照明的真实意义和具体内容,提出了中、小城市在改进夜光环境照明方面具体的措施和方法。     

基于MSP430F169的环境光自适应LED显示屏设计

本设计主要实现LED显示屏随着环境光改变其亮度,以避免白天显示不清或黑夜因太亮而炫目;并与上位机进行通信.本系统由MSP430F169单片机、16*32共阳极LED点阵显示屏、行驱动电路、列驱动电路、环境光自适应电路、数字开关调压电路、直流稳压源电路等组成.采用按列并行发送数据,按行扫描的方式实现LED点阵屏内容的显示;单片机通过数字开关调压电路实现对LED点阵屏电源电压的自动调节,使屏幕亮度随环境光自动变化.     

石灰土的增强改性研究

对生石灰取代消石灰和在生石灰中加入化学外加剂、活性混合材对石灰土性能的影响进行了研究,在此基础上研制一种AFS细粒土稳定结合料。AFS稳定土和石灰土相比,早期强度有了较大提高,并具有较好的抗裂性。     

液晶显示驱动方法的探讨

本介绍了液晶显示器件常见的驱动方法。主要包括1)静态驱动法2)动态驱动法3)双频驱动法4)非线性元件的应用5)各种射束寻址显示方式，并对此五种方法的优缺点进行了分析。