实心车轴的超声相控阵探伤

针对机车车轴的缺陷存在区域及其分布特点,分析利用超声相控阵技术进行机车车轴探伤的方法,提出一种新的机车车轴的相控阵超声检测方案,仅采用一个相控阵探头即可完成整个车轴的缺陷探测,且定位准确.结果表明,该系统可一次性完成对样板轴的全扫查,得出各缺陷所在位置及深度等定位信息,根据车轴缺陷检测数据结果可快速在车轴上找到缺陷,检测效率和检测精度较高,满足车轴检测工艺要求.     

表面撞击坑对高铁车辆空心车轴运行安全性评估的影响

基于断裂力学理论对含表面撞击坑高铁车辆空心车轴进行疲劳断裂安全性分析.考虑车轮与车轴、齿轮与车轴的过盈配合效应,在压装部引入残余压应力,根据车轴实物撞击坑形貌和尺寸建立仿真模型;采用385 km/h高铁车轴实测动应力,经变换获得一维七级载荷谱.分析结果表明：对于深度为300 μm的撞击抗,缺陷最深处的应力强度因子约为0.75 MPa·m1/2,远小于BS 7910 2005标准规定值,据此认为带有单个深度为300 μm撞击坑的空心车轴在正常服役期内不会发生裂纹萌生和扩展.研究结果可为我国高速列车检修规程和无损检测周期的制定提供参考.     

铁路货车轮对压装过程中影响压装力的因素及改进措施

本文分析了铁路货车车辆轮对在压装过程中影响压装力的诸多因素,分别从过盈量的合理选择、车轴轮座和车轮轮毂孔的加工表面粗糙度,压装时轮座表面和轮毂孔表面润滑油的合理使用,轮对压装设备自身精度、车轴和车轮在压装机上的安装位置精度、车轴轮座前端的引锥,以及车轮轮毂孔前端的退让引导圆弧、环境温度和湿度变化等方面系统分析了轮对压装力的影响,并提出了相应的解决办法和改进措施。     

PLC在车轴超声自动探伤系统中的应用

对车轴超声自动探伤作业的流程控制进行了研究,提出了工控机与PLC相结合的设计方案;采用“指令”与“报告”形式的应用层协议便捷的实现了二者问通讯;通过PLC的高速脉冲串功能（PTO）驱动步进电机实现了探头精确定位;基于模块化思想的软硬件设计,使得系统更易于调试和维护。     

AVR单片机的全方位雷达辅助行车系统设计

针对4探头倒车雷达常存在视觉盲区造成停车困难的问题,本文研究一种包含8探头的全方位雷达辅助行车系统.8个探头分别布置在车头和车尾,在车辆前进和倒车状态下分别启用不同位置的雷达,通过AVR单片机控制电路模块、超声波测距模块、液晶显示模块、蜂鸣器报警模块等实现多路障碍物的探测、距离显示和声音报警功能,以帮助驾驶员判断车辆距离障碍物的远近,全面了解车辆周围情况.     

基于超声波的车辆检测器设计

分析了国内外车辆检测的现状和存在的问题,针对车辆检测环境设计了超声波车辆检测器,该系统由超声波探头、主机以及通讯三部分构成,超声波探头以STC12C5412AD为微处理器,利用LM1812超声波收发器检测车辆信息,主机采用STC12C32S2为微处理器,对来自探头的数据进行分析、处理和存储,并把数据发回中央处理机;经过对样机大量的数据测试表明,该检测器检测车流量准确率可达99%,平均车速检测准确率可达90%,车型(三种)分类的精度可达94%,实际运行表明,该检测器工作可靠,可用于检测行驶中机动车的车高、车长、车速等参数。     

基于双秤台汽车衡的车辆动态称重算法

针对双秤台汽车衡的车辆动态称重进行了算法研究,提出了先使用小波变换对称重信号滤波预处理,使用专家系统识别车辆轴型,用车轴的速度计算加速度,最后依据双秤台传感器称重信号、速度信号、加速度信号、以及车辆轴型组建BP网络模型,利用BP网络算法良好的自我学习能力,对大量实测数据进行训练,达到了一定的动态称重测量精度,取得了较好的效果。     

基于AFV 技术的变结构体参数化设计方法研究

传统参数化方法难以适应变结构体设计,提出基于AFV(Abstract-Fuse-Verification) 技术的变结构体参数化设计方法。AFV 技术通过Abstract 将零件不同部位抽象形成模板库;Fuse 支持部位模板的设计和任意组合,提高了对变结构体设计的适应能力;Verification 按相关标准 校核结构尺寸以防止非法拓扑变异。而且,AFV 技术内部的类结构支持插件在不同CAD 平台 间切换。基于AFV 技术开发铁道车辆车轴参数化设计插件,实现了车轴的高效快速设计,验证 了AFV 技术的可行性。     

基于协同转向的铰接车辆轨迹跟随控制研究

针对铰接车辆后轴主动转向实现跟踪首轴轨迹的问题,本文提出一种基于多轴协同转向的补偿模糊PID控制方案.首先,根据各车轴具有同一转动中心的假设,利用扩展阿克曼转向原理确定了车轴的前馈控制转角;其次,依据首轴中心行驶轨迹,计算后轴的跟随偏差及变化率,并利用模糊PID控制理论,确定后轴的补偿控制转角,提高车辆的轨迹跟随控制性能;最后,在典型道路工况上,通过设置不同速度、道路附着系数及控制方案检验补偿模糊PID控制方案的轨迹跟随性能及鲁棒性.结果表明：在相同速度及道路附着系数下,相比于扩展阿克曼转向前馈控制及模糊PID控制方案,本文设计的补偿模糊PID控制进一步降低了轨迹跟随时各车体的横向偏差,并减小了车辆之间的横向铰接力;与PID控制相比,在不同速度及道路附着系数下,验证了补偿模糊PID控制具有一定的自适应性能.     

齿轮箱吊杆节点刚度对轴箱内置式高速列车驱动系统动态特性影响研究

为探明齿轮箱吊杆节点刚度对驱动系统悬挂节点力和驱动系统振动加速度的影响规律,以某型轴箱内置式高速动车为研究对象,基于多体动力学理论,建立了考虑驱动系统和齿轮啮合的车辆系统动力学模型,研究了齿轮箱吊杆节点刚度对齿轮箱吊杆节点力、电机吊点力、齿轮箱车轴铰接力、车辆平稳性和驱动系统振动加速度的影响.研究结果表明：由于1、2位驱动系统的齿轮啮合力方向不同,1位驱动系统悬挂节点的垂向力比2位驱动系统悬挂节点的垂向力大.齿轮箱吊杆节点刚度在1～30 MN/m增大时,1位齿轮箱吊杆节点力增大,1位电机吊点力减小,1位齿轮箱车轴铰接纵向力增大、横向力减小;2位齿轮箱吊杆节点力增大,2位电机吊点垂向力增大,纵向力和横向力减小,2位齿轮箱车轴铰接纵向力减小,横向力增大.齿轮箱吊杆节点刚度在30～100MN/m增大时,各悬挂节点力变化不明显.此外,车体的平稳性指标、电机和齿轮箱的振动加速度受齿轮箱吊杆节点刚度变化的影响较小.     

地铁列车制动力再分配优化控制研究

针对现有地铁列车在电-空制动力分配控制策略中没有充分考虑各轴应施加制动力存在差异的问题,对制动力再分配优化控制算法进行了研究。在对电制动优先的电-空制动力协调分配算法进行分析的基础上,以北京某地铁列车中2动1拖基本制动单元为研究对象,基于轴重转移原则,提出了根据各轮对所承受压力的大小按比例再分配空气制动力的优化控制算法,并通过Matlab/Simulink软件对地铁列车处于不同制动工况下制动力的再分配情况进行了仿真和分析。仿真结果表明,基于轴重转移的各轴空气制动力再分配优化控制策略有助于改善列车防滑性能、提高列车平稳制动的效果,达到了预期目标。     

四轴转向汽车起重机转向机构的CAD系统开发

本文讨论了四轴转向汽车起重机转向机构ＣＡＤ系统开发的必要性；介绍了在微型计算机上针对ＬＴ１０８０汽车起重机转向机构自行开发的ＣＡＤ系统。     

基于SERCOS总线的两足步行机器人分布式运动控制系统

本文介绍两足步行机器人运动控制系统结构的新发展,并介绍一种适于多轴运动控制 的通信系统——SERCOS总线,它的通信速率高,实时性和确定性好,很适合机器人各关节的 协调运动控制,便于构成分布式的机器人控制系统结构．文中讨论了基于SERCOS总线的两足 步行机器人控制系统结构设计,并分析了其优点．     

Practical active traction control for independent-wheel-drive electric vehicle based on slip-ratio threshold determination

The traditional traction control system (TCS) based on hydraulic braking only works when the wheels are slipping, which will cause the problem of slow response to extreme slip. In addition, the TCS of four-wheel-independent-drive electric vehicle (4WIDEV) is often based on road adhesion characteristics identification or optimal slip ratio identification to implement active control, which is difficult to achieve in engineering. Aiming at this problem, a practical active TCS is proposed in this paper. Firstly, according to the wheel slip state of the front and rear axles, the dynamic transfer of torque between axles is realized to maintain the vehicle propulsion power. Second, the adhesion conditions between road and tire are classified, and two sets of target slip ratio thresholds are formulated for high and low adhesion pavement, respectively. Then the current road adhesion coefficient is estimated by using the advantage that the in-wheel motor torque can be obtained in real-time. Thirdly, the overall framework of the control strategy is established, the logic threshold control algorithm is adopted for tracking the wheel target slip ratio. Finally, the simulation results show that the proposed active TCS can improve the vehicle power and avoid excessive wheel slipping.     

基于深度学习的智能治超场景下货车车型识别

针对智能治超场景下超载车辆自动化检测的需求,在YOLOv5s的基础上从数据、模型和算法三个方面提出了一种改进的货车车型识别算法。在数据层面,使用的数据增强模拟了现实中面对恶劣天气、图像噪声和数据损坏等复杂场景,丰富了训练数据的多样性,提高了模型在复杂场景下的鲁棒性。在模型方面,提出了一种新的注意力机制来综合考虑不同通道的重要性和编码特征的位置信息,提高了模型的识别准确性。在算法层面,针对现有算法的不足,提出了一种更通用的标准来判断货车与轮轴的隶属关系,以适用更复杂的场景。实验结果表明,提出的改进模型对货车和轮轴的识别精度分别达到99.34%和99.22%,对货车车型识别的准确率为98.71%。与经典的YOLOv5s网络相比,货车和轮轴的平均识别精度提高了2.39%,货车车型的识别准确率提高了2.22%。综上,所提出的方法实现了对货车车型自动和准确的识别,可以为智能治超场景下的货车车型识别提供理论支撑。     

多探测器的铁路轴温探测技术研究

对铁路红外轴温探测是目前判断列车安全与否的主要方法.由于现阶段对轴温探测多为单点式红外采集系统,使得问题车轴的判定具有较高的不可靠性.因此研究了四点线阵式红外探测器的铁路轴温探测系统,通过将数据融合思想和模式识别技术结合起来的方法,对问题车轴进行识别.此方法可有效解决以前的探测系统对单一红外探测器的不稳定性,能高效查找问题车轴,使高速列车的安全性在很大程度上得以提高.     

Hyperion project follows sun

Describes the field testing of the Hyperion robotics project which uses the concept of sun-synchronous navigation. Hyperion is made of aluminum tubing and has four, wheels on two axles. Each wheel has a motor, and the front axle has a passive joint that can roll and yaw relative to the back end. Hyperion steers by driving the wheels at different speeds, and the passive front-axle joint turns the robot in arcs. The 1.5 meter-high front axle gives the robot's digital cameras and laser scanner a view of surrounding terrain; the latter helps it detect close-range obstacles. A third panoramic camera offers remote observers a view of its surroundings. All other robot components are housed in the body, which is mounted between the axles. Hyperion uses a pair of global positioning system receivers and an odometric system to determine its position and orientation and wheel-based odometric:sensing to estimate motion. Odometry also enables positioning and orientation on other planets, where the robot could use things such as a star, sun, or terrain landmark in place of GPS. Multiple onboard sensors act as Hyperion's health-monitoring and fault-detection system, checking everything from computer processes and laser scanners to a sensor suite that monitors the rate at which the system receives GPS information. The planner combines a priori knowledge of terrain, planetary rotation, sun location, solar flux predictions, and predictions of rover capability.     

Coordinated Kinematic Control of Compliantly Coupled Multirobot Systems in an Array Format

This paper presents coordinated kinematic control of compliantly coupled multirobot systems for payload transportation. In the robot, unicycle-type axles are connected to a moving platform in an array format using compliant frames. A coordinate system is attached to an ideal center point on the platform to establish robot kinematics. In order to drive the system along a reference trajectory, we coordinate axle velocity commands, while considering frame compliance, nonholonomic constraints, and rigid body kinematics, respectively. These commands are further coordinated to consider configuration stability and physical limitations. Simulation and experimental results evaluate the coordination algorithms for various trajectories.      

Bridge roughness index as an indicator of bridge dynamic amplification

The concept of a road roughness index for bridge dynamics is developed. The international roughness index (IRI) is shown to be very poorly correlated with bridge dynamic amplification as it takes no account of the location of individual road surface irregularities. It is shown in this paper that a bridge roughness index (BRI) is possible for a given bridge span which is a function only of the road surface profile and truck fleet statistical characteristics. The index is a simple linear combination of the changes in road surface profile; the coefficients are specific to the load effect and span of interest. The BRI is well correlated with bridge dynamic amplification for bending moment due to 2-axle truck crossing events. A similar process can be used to develop a BRI for trucks with other numbers of axles or combinations of trucks meeting on a bridge.     

Kinematics of mobile manipulators and implications for design

A systematic, unified kinematic analysis for manipulator arms mounted to mobile platforms is presented. The differential kinematics for the composite system is used, along with an extended definition of manipulability, to generate a design tool for this class of systems. An example is presented in which a 3 DOF anthropomorphic manipulator is mounted on a platform powered by two independent drive wheels. Scaled manipulability ellipses are used to visualize the effect of manipulator mounting position on the overall mobility of the system. Given information about the intended tasks of the mobile manipulator, conclusions may be drawn as to the most appropriate mounting site. For the tasks which motivated this research, automated highway construction and maintenance, it was concluded that the manipulator base should be near the axles of the drive wheels and far from the centerline of the platform. © 2000 John Wiley & Sons, Inc.