铸造复合化技术与铸铁接合技术的动向

介绍了铸造复合化技术的发展新动向,着重阐述了压力浇注法、离心铸造法等新技术、新工艺;同时还叙述了铸铁接合技术的新进展;指出铸造复合化技术将对多功能铸件和复合化铸件的推广应用作出贡献。     

GPS在移动机器人导航定位系统中的应用

为了获得移动机器人定位数据的真实性，减少各种随机误差对定位精度的影响，通过运动载体当前统计模型，取位置作为观测量建立移动机器人动态定位模型，同时针对传统卡尔曼滤波的不足进行了分析，提出自适应卡尔曼滤波算法，该算法始终保持噪声模型接近于真实模型，从而较好地解决了GPS动态定位中状态噪声与观测噪声建模不准确和时变问题，在此基础上，通过模拟噪声和轨迹曲线，进行了仿真，结果显示效果显著。     

连山大桥泥石流沟灾害特征分析

2013年7月10日和7月12日在强降雨的作用下,连山大桥泥石流沟连续两次发生泥石流,造成都汶高速公路和G213线200 m长度范围内堆积泥石流约8万m3,汶川至都江堰的交通中断。以连山大桥泥石流沟为研究对象,分别从流域因素、物源和水源这三个方面分析泥石流的形成原因,并分析泥石流的成灾过程机制,以及计算泥石流的运动参数和泥石流发展趋势及影响范围,提出防治工程措施。     

Robust hierarchical controller with conditional integrator based on small gain theorem for reference trajectory tracking of autonomous vehicles

ABSTRACT

A robust trajectory tracking controller is designed for autonomous vehicles based on a hierarchical architecture to make the autonomous vehicle track a given reference trajectory. The controller consists of two sub controllers: kinematic controller and dynamic controller. Based on the kinematics of tracking reference trajectory, a desired yaw rate is calculated by kinematic controller to make the lateral deviation global asymptotic stable. Then, steering wheel angle is calculated by a vehicle dynamic controller to make the vehicle yaw rate converge to the desired value and make the vehicle dynamic stable. Conditional integration method is used in the sub controllers. This method guarantees global asymptotic stability of tracking reference values and considers the uncertainty of parameters and constraints of desired yaw rate and actuators. Then based on small-gain theorem, the condition of the finite-gain L stability is given to the hierarchical controller to ensure the interconnected sub systems stable and prevent the amplification of system disturbance. Finally, the effectiveness and robustness of the controller are validated by real vehicle experiments.     

剪叉式升降台液压缸布置的运动学及动力学分析

利用速度瞬心法和虚位移原理分别对3种液压缸布置型式的剪叉式升降台进行运动学及动力学分析,得出液压缸活塞运动速度与升降台升降速度的关系式以及液压缸推(拉)力与升降载荷的关系式,并利用Matlab结合升降台实例对3种液压缸布置型式下的升降台升降速度及恒定载荷下的液压缸推(拉)力随升降高度的变化规律进行对比分析,为液压缸的选型及布置优化提供一定的理论依据。     

客车侧翻的运动学分析

从运动学的角度出发,进行了影响客车侧翻因素的实例分析,得到了影响因素与客车侧翻稳定性的定量关联,从而获得了提高客车侧翻稳定性的措施.概括了客车侧翻的原因,论述了造成客车侧翻极其恶劣结果的原因,提出了影响客车侧翻的3方面因素.从3方面影响因素对侧翻稳定性的运动学进行了分析,并以滨保高速事故中的客车为实例,对分析结果进行了验证.在此基础上,提出了提高客车侧翻稳定性的措施.     

柴油发动机缸盖气门座高频感应淬火技术及其工艺质量控制

介绍了缸盖阀座高频淬火技术的工艺实现、装备实现和影响淬火质量的主要因素,从而提出理想的工艺参数和装备条件的搭配,对该技术的应用推广具有指导意义。     

Spillback congestion in dynamic traffic assignment: A macroscopic flow model with time-varying bottlenecks

In this paper, we propose a new model for the within-day Dynamic Traffic Assignment (DTA) on road networks where the simulation of queue spillovers is explicitly addressed, and a user equilibrium is expressed as a fixed-point problem in terms of arc flow temporal profiles, i.e., in the infinite dimension space of time’s functions. The model integrates spillback congestion into an existing formulation of the DTA based on continuous-time variables and implicit path enumeration, which is capable of explicitly representing the formation and dispersion of vehicle queues on road links, but allows them to exceed the arc length. The propagation of congestion among adjacent arcs will be achieved through the introduction of time-varying exit and entry capacities that limit the inflow on downstream arcs in such a way that their storage capacities are never exceeded. Determining the temporal profile of these capacity constraints requires solving a system of spatially non-separable macroscopic flow models on the supply side of the DTA based on the theory of kinematic waves, which describe the dynamic of the spillback phenomenon and yield consistent network performances for given arc flows. We also devise a numerical solution algorithm of the proposed continuous-time formulation allowing for “long time intervals” of several minutes, and give an empirical evidence of its convergence. Finally, we carry out a thorough experimentation in order to estimate the relevance of spillback modeling in the context of the DTA, compare the proposed model in terms of effectiveness with the Cell Transmission Model, and assess the efficiency of the proposed algorithm and its applicability to real instances with large networks.     

高速公路作业区交通流的运动学波分析

首先回顾了运动学波理论的研究进展,根据高速公路作业区汇合交通流特性,利用运动学波理论建立了高速公路作业区交通流模型。进而对高速公路作业区的交通波动做了理论上的分析,根据瓶颈处上下游的交通需求和供给的不同关系归纳了4种不同情形,以一种最为复杂的情形为例从理论上分析了作业区内激波的动态变化过程,绘出了交通流基本图和车辆轨迹图中的各种激波的示意图。最后以实际算例的形式详细计算了理论分析的结果,并针对结果对高速公路作业区的交通控制策略提出了建议,为高速公路作业区的交通控制奠定了理论基础。     

GPS RTK技术在高等级公路中线定测中的应用

目前,实时动态测量（Real Time Kinematic,RTK）技术日臻成熟,并逐步在高等级公路中线定测中得到应用。基于RTK技术的基本原理及系统组成,通过生产实例验证RTK施工放样的精度和可靠性,结果表明：RTK测量可以较好地满足公路设计和施工中的定线测量的要求。