适用于真空管道交通的高温超导磁悬浮车低温液氮容器

真空管道运输系统的建成以及在全球的普及与应用,将是继火车、汽车、飞机和IT之后人类的又一大福祉。将使今天面临的交通困境从根本上得以解决,也将给全球经济与社会生活方式带来全新的变化。磁悬浮车是真空管道交通系统的运行主体,在各种不同模式的磁悬浮车中,高温超导磁悬浮车非常适合于真空管道交通。然而,由于真空管道中是低压环境,用于常压环境的高温超导磁悬浮车低温液氮容器不适合直接用于真空管道交通系统。提出在真空管道交通中,采用带压力阀的高温超导磁悬浮车低温液氮容器。这是一种压力容器,器壁要承受压差,当前常用的矩形高温超导磁悬浮车低温液氮容器则不适合,进一步提出能承受较高压力的圆柱形低温液氮容器的设计构想。还对真空管道交通中真空环境对提高液氮容器保温效果的意义进行了讨论。     

非金属低温杜瓦装置的研制

报道了一种非金属杜瓦装置的研制,以满足高温超导磁悬浮车系统对液氮低温容器的要求。这种长方体低温容器采用无磁非金属材料制备,从而可以避免由涡流导致的阻力和热损耗,以及由磁性导致的吸引力等不利于高温超导磁悬浮车系统的影响。容器的液氮损耗率为0.55L/h。综合性能测试表明,该非金属杜瓦可以作为高温超导磁浮车低温容器的理想选择之一。     

基于超导块材磁刚度特性的永磁轨道优化设计

目前高温超导磁悬浮实验车使用的是单极永磁轨道(PMG).为了提高磁悬浮车的运行稳定性,人们做出了大量的研究.磁悬浮刚度是设计优化高温超导磁悬浮车的一项很重要的参数.文中研究了七块YBCO块材阵列在两种结构不同的永磁轨道上方的竖直方向刚度和横向力刚度的特性.通过比较测试结果,得出七块YBCO阵列与双极型永磁轨道组成的磁悬...     

车载高温超导磁悬浮系统的设计

介绍车载高温超导磁悬浮系统的设计问题。为了完成系统的设计 ,首先进行了单块和多块YBCO高温超导体块材的悬浮力的研究 ,同时考虑了 YBCO高温超导体块材的选取问题。设计的目标是稳定悬浮 350 kg,采用 8个车载液氮低温容器 ,这种容器是底壁仅 3mm厚的长方体形的。     

应用场结构对YBCO块材悬浮性能的影响

永磁轨道是高温超导磁悬浮车的重要组成部分之一,对YBCO块材在两种应用场:单峰永磁轨道和双峰永磁轨道上的磁悬浮性能进行了数值和实验研究。通过对比两种轨道上方的切向和法向分量的磁场分布,对实验结果进行了分析。实验发现YBCO块材在双峰轨道上方,悬浮力和导向力均大于单峰轨道,双峰轨道在磁利用率方面高于单峰轨道。     

基于单边强磁场效应的无轨磁悬浮小车

利用永磁磁轮产生的感应磁场与原来的磁场方向相反的排斥力来实现磁悬浮。永磁轮磁体按照海尔贝克阵列排列。利用AnsoftMaxwell 16.0软件对永磁轮磁场进行了模拟,对感应磁场进行仿真分析,进一步制作了无轨磁悬浮小车模型,实现了无磁质轨道悬浮,并且研究了气隙高度、以及电机工作电压与悬浮力的关系。     

低温容器中超导块材悬浮与导向性能研究

本文主要研究超导磁悬浮系统中超导块材与永磁导轨之间的相互作用力,通过浸于低温容器中的超导块材与三磁峰轨道之间不同排布方式的实验,测试不同悬浮间距的悬浮力,以及在一定场冷距离下超导块材在三磁峰轨道上方不同水平位移段的导向力。结果表明,悬浮间隙越大,超导块材中心与三磁峰轨道中心水平偏移越小,悬浮力越大;在一定悬浮间距下,超导块材与三磁峰轨道之间水平位移越大,导向力越大。     

TSPMP法制备的单畴GdBaCuO块材的磁悬浮力和捕获磁通的特性研究

本文对φ20mm,φ30mm的GdBaCuO超导块材在液氮温区的磁悬浮特性及捕获磁通进行了研究,77K零场冷条件下,GdBaCuO超导块材磁悬浮力密度在2～10N/cm2.对不同Gd211含量的GdBaCuO超导块材的磁悬浮力和捕获磁通性能进行了对比,发现对φ30mm的样品,40%molGd211(Gd1.8)的GdBaCuO超导块材捕获磁通性能最高.同时对比了GdBaCuO和YBCO超导块材的磁悬浮力和捕获磁通性能,结果表明GdBaCuO与YBCO超导块材在相同的磁悬浮力性能下,捕获磁通性能大于YBCO超导块材.     

高温超导高速磁浮交通系统悬浮导向与牵引方案研究

本文提出了一种全高温超导高速磁悬浮交通技术模式, 该技术模式采用高温超导钉扎悬浮导向和高温超导直线电机牵引, 具有高速运行、 静态悬浮和动态自稳定悬浮导向三大特征. 根据5 编组时速500 公里磁悬浮列车的运行要求和工况, 本文对高温超导钉扎悬浮导向系统和高温超导直线牵引系统进行了方案设计, 并通过有限元仿真对所提方案进行了可行性分析和验证. 结果证明了全高温超导磁悬浮系统的高速运行、 静态悬浮和动态自稳定悬浮导向技术优势和设计方案的可行性.     

HTS磁悬浮电磁发射系统中直线电机起动性能研究

在高温超导(HTS)磁悬浮电磁发射系统中,采用长初级双边直线感应电机进行驱动.同单边直线电机相比,双边直线感应电机由于对称的初级结构,次级结构所受的垂直力为零,这大大提高了直线电机的驱动性能和稳定性.利用旋转电机的经典分析方法,分析了长初级双边直线感应电机不同绕组分布时的绕组因数.结果表明,当采用分布式短距绕组时,可以有效的抑制合成气隙磁场中的谐波分量,改善气隙磁动势波形,进而提高电机的性能和效率.通过Ansoft Maxwell软件仿真求解了6种不同绕组分布时的电机气隙磁场分布,分别求解了整距和分布式短距绕组的电机起动推力,验证了理论分析的正确性.最后,设计制作了分布短距实验样机,并对起动推力进行了测试.结果表明电机起动推力平稳,为复合HTS磁悬浮电磁发射系统设计提供参考.     

ANALYSES OF DYNAMIC RESPONSE OF VEHICLE AND TRACK COUPLING SYSTEM WITH RANDOM IRREGULARITY OF TRACK VERTICAL PROFILE

A dynamic computational model for the vehicle and track coupling system is developed by means of finite element method in this paper. In numerical implementation, the vehicle and track coupling system is divided into two parts; lower structure and upper structure. The vehicle as the upper structure in the coupling system is a whole locomotive or rolling stock with two layers of spring and damping system in which vertical and rolling motion for vehicle and bogie are involved. The lower structure in the coupling system is a railway track where rails are considered as beams with finite length rested on a double layer continuous elastic foundation. The two parts are solved independently with an iterative scheme. Coupling the vehicle system and railway track is realized through interaction forces between the wheels and the rail, where the irregularity of the track vertical profile considered as stationary ergodic Gaussian random processes and simulated by trigonometry series is included. The amplitudes of vibrations, their velocities and the accelerations generated in the vehicle and rail and the interaction forces between the vehicle and the rail due to the random irregularity of the track vertical profile and different line grades and train speeds have been analyzed numerically by this model. Analyses of system responses are performed in time and frequency domains.     

智能车转向系统的研究及设计

智能车的底层控制主要包括油门、刹车和转向三部分。转向部分主要以电子式助力转向系统(EPS)为基础进行设计。电子控制式电动助力转向系统具有较好的操纵性、安全性、轻便性以及节能性等优点。然而,传统汽车上应用的助力转向系统仅起到辅助作用,对于无人驾驶的智能车来说功率过小,无法实现智能车在静止或者低速行驶时的转向控制,并且智能车的转向控制策略也有所不同。通过选择合理的转向电机、合适的传感器,设计了一套适合智能车的转向系统。通过反复试验,该转向系统可以很好的实现智能车转向控制。     

Reducing slab track vibration into bridge using elastic materials in high speed railway

In this paper, the problem of vibration transmission from slab track structures into bridge is studied by theoretical analysis. A vehicle-track-bridge coupling system dynamics model is established based on a multibody dynamics theory and a finite element method. The system model consists of vehicle model, track-bridge model and wheel/rail interaction model. The vehicle model is established based on the multibody dynamics theory, and the tack-bridge model is established by the finite element method. The vehicle model and track-bridge model are coupled through wheel/rail interaction model, and the track irregularities are included. The system dynamic responses are calculated, and the effectiveness of elastic materials in vibration reducing is discussed. The results demonstrate that elastic materials like slab mat layer inserted between slab track and bridge can reduce vibration transmitted from track into the bridge. Some suggestions for the design and application of slab mat are provided in the end of the paper.     

基于补偿控制的无人地面车辆轨迹跟踪方法

针对无人地面车辆轨迹跟踪精度不高,鲁棒性差的问题,提出了一种基于补偿控制的算法。该算法分为运动学和动力学两部分：基于方向角调整策略的运动学控制律能确保无人地面车辆有效跟踪参考轨迹;基于PD与模型参考模糊滑模自适应控制相结合控制的动力学控制律能有效补偿建模不精确和外界扰动带来的影响。仿真结果表明：该算法能够有效跟踪参考轨迹,控制量分配合理且鲁棒性较好。     

Symplectic random vibration analysis of a vehicle moving on an infinitely long periodic track

Based on the pseudo-excitation method (PEM), symplectic mathematical scheme and Schur decomposition, the random responses of coupled vehicle-track systems are analyzed. The vehicle is modeled as a spring-mass-damper system and the track is regarded as an infinitely long substructural chain consisting of three layers, i.e. the rails, sleepers and ballast. The vehicle and track are coupled via linear springs and the “moving-vehicle model” is adopted. The latter assumes that the vehicle moves along a static track for which the rail irregularity is further assumed to be a zero-mean valued stationary Gaussian random process. The problem is then solved efficiently as follows. Initially, PEM is used to transform the rail random excitations into deterministic harmonic excitations. The symplectic mathematical scheme is then applied to establish a low degree of freedom equation of motion with periodic coefficients. In turn these are transformed into a linear equation set whose upper triangular coefficient matrix is established using the Schur decomposition scheme. Finally, the frequency-dependent terms are separated from the load vector to avoid repeated computations for different frequencies associated with the pseudo-excitations. The proposed method is subsequently justified by comparison with a Monte-Carlo simulation; the fixed-vehicle model and the moving-vehicle model are compared and the influences of vehicle velocity and class of track on system responses are also discussed.     

A dynamic model for an asymmetrical vehicle/track system

A finite element model to simulate an asymmetrical vehicle/track dynamic system is proposed in this paper. This model consists of a 10-degree-of-freedom (d.o.f.) vehicle model, a track model with two rails, and an adaptive wheel/rail contact model. The surface defects of wheels and rails can be simulated with their geometry and an endless track model is adopted in the model. All time histories of forces, displacements, velocities and accelerations of all components of the vehicle and track can be obtained simultaneously. By using this model, one can study the effect that wheel/rail interaction from one side of the model has on the other. This can be done for many asymmetrical cases that are common in railway practice such as a wheel flat, wheel shelling, out-of-round wheel, fatigued rail, corrugated rail, head-crushed rail, rail joints, wheel/rail roughness, etc. Only two solutions are reported in this paper: steady state interaction and a wheel flat.     

Noise control for rapid transit cars on elevated structures

Noise control treatments for the propulsion motor noise of rapid transit cars on concrete elevated structures and the noise reduction from barrier walls were investigated by using acoustical scale models and supplemented by field measurements of noise from trains operated by the Port Authority Transportation Corporation (PATCO) in New Jersey. The results show that vehicle skirts and undercar sound absorption can provide substantial cost-effective reductions in propulsion noise at the wayside of transit systems with concrete elevated guideways. The acoustical scale model noise reductions applied to PATCO vehicles on concrete elevated structures show reductions in the A-weighted noise levels of 5 dB for undercar sound absorption, 5 dB for vehicle skirts, and 10 dB for combined undercar absorption and vehicle skirts. Acoustical scale model results for sound barrier walls lined with absorptive treatment showed reductions from 7 dB to 12 dB of noise from vehicles in the far track, depending on the height of the wall, and reductions from 12 dB to 20 dB of noise from vehicles on the near track. Transit vehicles at high speeds where propulsion system noise dominates are 7 dB(A) noisier at 50 ft on concrete elevated structures than on at-grade on tie and ballast. Of this amount, 3 dB is due to loss of ground effect, and 4 dB is due to the absence of undercar absorption provided by ballast.     

超导磁悬浮的物理演示

论述一台高临界温度超本磁悬浮列车物理课堂演示装置，该装置为一个盛放高监界温度超导体的列车模型，在具有磁束缚的封闭磁轨道上方悬浮；或在磁轨道下方倒挂“悬浮”，并可在直线电机加速装置或旋转磁场加速装置作用下，沿这一长度约为１．７ｍ的封闭磁轨道，以悬浮或倒挂“悬浮”状态无摩擦地连续运转。     

A NEW SLIDING MODE CONTROL FOR A CLASS OF UNCERTAIN TIME-DELAY CHAOTIC SYSTEMS

We propose a new sliding mode control scheme for a class of uncertain time-delay chaotic systems. It is shown that a linear time invariant system with the desired system dynamics is used as a reference model for the output of a time-delay chaotic system to track. A sliding mode controller is then designed to drive the output of the time-delay chaotic system to track the desired linear system. On the sliding mode, the output of the controlled time-delay chaotic system can behave like the desired linear system. A simulation example is given in support of the proposed control scheme.     

机动车协商模型与分岔特性研究

在环行交叉路口交通流中, 由于行驶目的的不同存在三种类型冲突. 为了真实模拟人类的自治性和智能性, 先将机动车建立为一个含有驾驶员模型的智能体, 再耦合环行交叉口的元胞自动机模型组成多智能体系统. 在总结每种类型交通冲突特点和规律的基础上, 提出通过优先级策略和动态协商机制消解机动车智能体相互之间的冲突问题. 以某中小城市城的典型环行交叉路口交通流量为样本数据, 对比验证模型的正确性, 并且进一步研究了交通流的分岔特性, 发现一定条件下流量的周期分岔和混沌现象. 数值模拟结果表明, 所建模型符合实际情况, 并且内环发生冲突越严重车流量越低, 随着机动车属性参数k和p的变化, 系统从稳定走向分岔再到混沌. 关键词： 多智能体 元胞自动机 协商 分岔