Experimental investigation on vibration characteristics of the medium-low-speed maglev vehicle-turnout coupled system

The steel turnout is one of the key components in the medium–low-speed maglev line system.However,the vehicle under active control is prone to vehicle–turnout coupled vibration,and thus,it is necessary to identify the vibration characteristics of this coupled system through field tests.To this end,dynamic performance tests were conducted on a vehicle–turnout coupled system in a medium–low-speed maglev test line.Firstly,the dynamic response data of the coupled system under various operating conditions were obtained.Then,the natural vibration characteristics of the turnout were analysed using the free attenuation method and the finite element method,indicating a good agreement between the simulation results and the measured results;the acceleration response characteristics of the coupled system were analysed in detail,and the ride quality of the vehicle was assessed by Sperling index.Finally,the frequency distribution characteristics of the coupled system were discussed.All these test results could provide references for model validation and optimized design of medium–low-speed maglev transport systems.

μ-Syntheses of Suspension Systems for EMS and EDS Maglev Vehicles

Under model uncertainty and complex disturbance, the robust control strategy should be used in suspension control systems for various Maglev vehicles to obtain ride comfort of passengers. In this paper, the robust controllers are synthesized using μ approach for levitation system of electromagnetic Maglev vehicle and active suspension system of super conducting Maglev vehicle. The numerical simulations for different parameter perturbations and different disturbances are accomplished, and a comparison of μ control and H ∞ control is performed. The simulation results show that, both H ∞ control and μ control for two kinds of Maglev vehicles exhibit good stability robustness to plant model uncertainty, but μ control exhibits better performance robustness than H ∞ control, therefore better ride quality could be obtained by μ control.

Structure analysis of levitation chassis of medium-to-low speed maglev vehicles based on left-right decoupling

Levitation chassis, as an extremely important component of maglev vehicles, provides functions of transmitting levitation force and steering force, and directly affects the safety performance of the vehicle. Based on the vertical dynamics model of the levitation chassis, kinetic equations of the model are established, and a simulation program is designed to analyze the structural decoupling function of the chassis, especially under the influence of elastic constraints between the left and right modules, which are exclusively owned by maglev vehicles. A finite element model of the levitation chassis based on left-right decoupling is constructed. Analysis results of the model show that the mechanical properties of the chassis tailored for the vehicle meet the design requirements, and the stiffness and strength is adequate to bear the weight of the whole vehicle.

Control strategy of maglev vehicles based on particle swarm algorithm

Taking a single magnet levitation system as theobject, a nonlinear numerical model of the vehicle–guidewaycoupling system was established to study the levitationcontrol strategies. According to the similarity in dynamics,the single magnet-guideway coupling system was simplifiedinto a magnet-suspended track system, and the correspondinghardware-in-loop test rig was set up usingdSPACE. A full-state-feedback controller was developedusing the levitation gap signal and the current signal, andcontroller parameters were optimized by particle swarmalgorithm. The results from the simulation and the test rigshow that, the proposed control method can keep the systemstable by calculating the controller output with the fullstateinformation of the coupling system, Step responsesfrom the test rig show that the controller can stabilize thesystem within 0.15 s with a 2 % overshot, and performswell even in the condition of violent external disturbances.Unlike the linear quadratic optimal method, the particleswarm algorithm carries out the optimization with thenonlinear controlled object included, and its optimizedresults make the system responses much better.

Physical modeling of long-term dynamic characteristics of the subgrade for medium-low-speed maglevs

To investigate the dynamic characteristics and long-term dynamic stability of the new subgrade structure of medium-low-speed(MLS)maglevs,cyclic vibration tests were performed under natural and rainfall conditions,and the dynamic response of the subgrade structure was monitored.The dynamic response attenuation characteristics along the depth direction of the subgrade were compared,and the distribution characteristics of the dynamic stress on the surface of the subgrade along the longitudinal direction of the line were analyzed.The critical dynamic stress and cumulative deformation were used as indicators to evaluate the long-term dynamic stability of the subgrade.Results show that water has a certain effect on the dynamic characteristics of the subgrade,and the dynamic stress and acceleration increase with the water content.With the dowel steel structure set between the rail-bearing beams,stress concentration at the end of the loaded beam can be prevented,and the diffusion distance of the dynamic stress along the longitudinal direction increases.The dynamic stress measured in the subgrade bed range is less than 1/5 of the critical dynamic stress.The postconstruction settlement of the subgrade after similarity ratio conversion is 3.94 mm and 7.72 mm under natural and rainfall conditions,respectively,and both values are less than the 30 mm limit,indicating that the MLS maglev subgrade structure has good long-term dynamic stability.

Study on Feasibility of Reusable Rocket Launching Technology by Use of Scramjet and Maglev Technologies

The scramjet and maglev engineering technology development and trends at home and abroad are firstly presented in this paper. A new launch mode of space transportation system is proposed based on scramjet and magnetic suspension technologies, and its key technologies required are given. This paper also makes analysis on using scramjet and magnetic suspension technologies to launch a reusable rocket, and the results show that a normal temperature conductor maglev launch system is feasible.

超导钉扎高速磁浮车-轨耦合动力学建模与仿真

为探究超导钉扎磁浮车辆高速运行动态特性,建立车-轨耦合空间模型,开展不同车速下的动力学仿真。结合有限元方法获得磁轨关系数学模型;基于牛顿-欧拉法建立车辆模型,引入截短梁描述建立永磁轨道模型;以磁轨关系为纽带获得超导钉扎磁浮车-轨空间耦合动力学模型;利用Matlab对模型进行仿真,分析轨道振动、电机法向力和轨道不平顺等对超导钉扎磁浮车辆-轨道系统动态响应的影响。结果表明:磁浮车辆系统的振动受轨道不平顺和车速的影响较大,受轨道振动的影响可忽略不计;在速度为620 km/h时,车体、悬浮架的最大振动加速度分别保持在0.5、8 m/s^(2)以下,具有较好的乘坐舒适性。建立的模型可为超导钉扎磁浮交通线路设计与参数优化等研究提供帮助。

基于等效刚度阻尼系统的中低速磁浮列车与大跨度桥梁耦合振动响应分析

针对中低速磁浮列车与大跨度连续梁桥的耦合动力响应问题,本文基于等效刚度阻尼系统建立多编组磁浮列车模型;基于国内在建磁浮专线连续梁桥(35m+55m+35m),采用ANSYS中实体单元建立全桥模型.并将两个独立系统在SIMPACK进行车桥耦合,设定车重参数分别为空载、定员和超载,且列车按单线和双线工况运行,计算耦合系统的动力响应.结果表明,本文建立的列车模型受到轨道激励时,磁浮间隙在额定范围内浮动,即等效刚度阻尼系统有良好的控制效果;车辆磁浮间隙的变化量、车体竖向加速度与车重成反比,而磁浮力与车重成正比;在计算工况下,桥梁主跨及边跨的竖向位移均满足设计要求的限值,双线列车超载运行桥梁跨中最大位移仅为4.503mm.说明连续梁桥具有较大的刚度,能满足磁浮车辆安全运行的要求;对比列车单双线运行,主跨跨中的竖向位移最大值后者达到前者两倍,而边跨位移的最大值后者仅比前者增大70%,表明双线列车对开运行对桥梁的动力响应存在增大效应.相关研究成果对磁浮线路建设有一定参考意义.

预应力效应对中速磁浮线路简支梁车-桥耦合振动响应的影响

以长沙磁浮线路简支梁桥为研究对象,建立考虑不同预应力效应的磁浮线路简支梁桥车-桥耦合振动模型,分析预应力效应对中速磁浮线路车-桥耦合振动响应的影响。结果表明:预应力效应的变化对桥梁动力响应影响明显,预应力增加显著加剧桥梁竖向振动加速度,预应力由0.67P0(P0为张拉控制应力)增加到1.33P0时,桥梁跨中竖向最大加速度从0.21 m/s^(2)增至0.44 m/s^(2);车速增加会加剧预应力效应的影响,对桥梁竖向振动加速度的影响尤为明显,车速由20 km/h增加到200 km/h时,在1.00P0作用下,桥梁跨中竖向最大加速度从0.15 m/s^(2)增至0.76 m/s^(2);箱壁局部变形对车-桥耦合竖向振动响应有显著影响,预应力导致的箱壁局部变形不可忽略。

中低速磁浮车辆悬浮故障工况动力学分析

为研究中低速磁浮车辆电磁铁失效失去悬浮力时的故障工况对磁浮车辆动力学性能的影响,建立三悬浮架中低速磁浮车辆动力学模型,对直线运行和曲线通过性能的各项动态指标进行仿真分析。结果表明:电磁铁失效故障对平稳性指标和导向间隙影响较小,对悬浮间隙、悬浮模块点头角和通过速度影响较大;发生电磁铁失效故障时,直线路段需要限速60 km/h运行,R100曲线路段需要限速38 km/h运行。

Hierarchical model updating for high-speed maglev vehicle/guideway coupled system based on multiobjective optimization

The high-speed maglev vehicle/guideway coupled model is an essential simulation tool for investigating vehicle dynamics and mitigating coupled vibration.To improve its accuracy efficiently,this study investigated a hierarchical model updating method integrated with field measurements.First,a high-speed maglev vehicle/guideway coupled model,taking into account the real effect of guideway material properties and elastic restraint of bearings,was developed by integrating the finite element method,multi-body dynamics,and electromagnetic levitation control.Subsequently,simultaneous in-site measurements of the vehicle/guideway were conducted on a high-speed maglev test line to analyze the system response and structural modal parameters.During the hierarchical updating,an Elman neural network with the optimal Latin hypercube sampling method was used to substitute the FE guideway model,thus improving the computational efficiency.The multi-objective particle swarm optimization algorithm with the gray relational projection method was applied to hierarchically update the parameters of the guideway layer and magnetic force layer based on the measured modal parameters and the electromagnet vibration,respectively.Finally,the updated coupled model was compared with the field measurements,and the results demonstrated the model’s accuracy in simulating the actual dynamic response,validating the effectiveness of the updating method.

Development of new electromagnetic suspension-based high-speed Maglev vehicles in China:Historical and recent progress in the field of dynamical simulation

High-speed Maglev is a cutting-edge technology brought back into the focus of research by plans of the Chinese government for the development of a new 600 km/h Maglev train.A Chinese‐German cooperation with industrial and academic partners has been established to pursue this ambitious goal and bring together experts from multiple disciplines.This contribution presents the joint work and achievements of CRRC Qingdao Sifang,thyssenkrupp Transrapid,CDFEB,and the ITM of the University of Stuttgart,regarding research and development in the field of high‐speed Maglev systems.Furthermore,an overview is given of the historical development of the Transrapid in Germany,the associated development of dynamical simulation models,and recent developments regarding high-speed Maglev trains in China.

基于磁场非线性的中低速磁悬浮鲁棒自适应控制

为了保障磁悬浮列车的悬浮稳定性,研究了中低速磁悬浮列车在磁场非线性和轨道不平顺激扰下的悬浮控制问题。首先,基于有限元方法分析了动态和静态磁场特性,建立了考虑磁饱和及涡流效应的悬浮力模型,并以该悬浮力模型为基础建立了单个悬浮单元的数学模型;然后,提出了一种鲁棒自适应控制方法,在广义(比例-积分)PI控制框架下,设计了自适应律灵活调节控制参数,并采用李雅普诺夫方法证明了闭环系统内所有信号均是最终一致有界的;最后,在整车动力学模型上进行多种工况的仿真分析,验证了所提出控制方法的有效性。结果表明,在正弦和随机激扰下,鲁棒自适应控制的气隙跟踪误差都降低70%以上;在竖曲线工况下,相较于传统(比例-积分-微分)PID控制,同一个悬浮模块的前后悬浮点最大气隙跟踪误差的差值分别从1.5718 mm和1.2278 mm下降到0.1952 mm和0.3962 mm。

中低速磁浮车辆悬浮控制器可靠性优化设计研究

[目的]悬浮控制器是中低速磁浮车辆的关键部件,其可靠性直接影响中低速磁浮车辆悬浮系统的稳定性及可靠性,需对悬浮控制器的可靠性进行优化。[方法]以单个悬浮电磁铁(内含2个悬浮控制器)为研究对象,分析了悬浮控制器的可靠性,建立了悬浮控制器的可靠性模型,开展了悬浮控制器故障树分析,找出影响悬浮控制器的关键因素。提出了悬浮控制器的优化方案,将单个悬浮电磁铁内含的2个悬浮控制器优化为1个悬浮控制器,并对部分关键部件进行了冗余设计。基于优化后悬浮控制器的电路原理,建立了优化后悬浮控制器的可靠性模型及故障树模型,并对悬浮控制器优化前后的可靠性进行对比分析。[结果及结论]与优化前单个悬浮电磁铁中2个悬浮控制器的总失效率(2.282×10^(-6)h^(-1))相比,优化后单个悬浮电磁铁悬浮控制器的失效率为1.064×10^(-6)h^(-1),失效率降幅为53.37%。优化后悬浮控制器的可靠度明显高于优化前悬浮控制器的可靠度。

磁浮车辆运行平稳性的虚拟激励分析方法

为方便、快速地分析多点输入轨道车辆的平稳性,基于虚拟激励原理,提出了平稳性分析方法。当车辆系统受多点全相关随机激励时,应用此方法将多输入多输出系统的响应功率谱矩阵的计算化简为两个矢量相乘,利用所获得的功率谱和随机振动中的反演技术,分析轨道车辆的平稳性指标。以TR08磁浮车辆为原型,建立了磁浮车辆的垂向动力学模型,运用虚拟激励分析方法计算了磁浮车辆的响应功率谱。在频域中,磁浮车辆车体中心处的Sperling指标为1.653,车辆的平稳性等级为优,通过反演运算获得了响应的幅值谱和时间历程,分析过程简单,计算结果准确。

磁悬浮车辆结构动力学建模与仿真

为了准确获得磁悬浮车辆结构的动力学特性,结合上海磁悬浮示范线车辆,对磁悬浮车辆结构建模和仿真方法展开研究。通过分析整体结构受力载荷工况,给出夹层和车体结构的受力公式。采用参数化和子结构建模技术,利用多体系统软件SIMPACK建立磁悬浮车辆首车动力学模型。为简化整个磁悬浮车辆系统多体模型和提高计算效率,将车辆受到的作用力和部分刚体简化为力元或力矩。仿真结果表明,多体动力学建模可以作为磁悬浮车辆结构设计方案优劣的有效评估工具,有益于磁悬浮结构国产化设计和开发。

低速磁浮车辆动力学建模与导向机构仿真分析

在分析低速磁浮车辆结构及其运动学关系基础上,利用SIMPACK软件,建立了含主动悬浮控制的76个自由度的磁浮车辆虚拟样机模型,开展了基于整车动力学的低速磁浮车辆导向机构仿真分析,研究了T形臂、横向滑台及两者之间的运动学规律。仿真结果表明:在300 m半径曲线和三转向架结构条件下,为了保证磁浮车辆顺利通过曲线,磁浮车辆导向机构前T形臂长度应大于后T形臂长度,两者比值的优化区域在1.50和2.00之间;车辆头尾T形臂相对于车体的转角幅值大小基本相同,方向相反,对应滑台的横向位移曲线形状与幅值基本相同;同一转向架前后滑台的最大横移量之比等于前后T形臂长度之比。

基于SIMPACK的磁悬浮车辆耦合动力学性能仿真模型

为了有效评价磁悬浮车辆动力学性能,引入SIMPACK仿真软件,根据磁悬浮车辆多体系统动力学拓扑关系图,建立了磁悬浮车辆-轨道-控制系统的耦合动力学模型,分析了试验结果和仿真结果。在模型中,磁悬浮车辆被视为多刚体,并具有两系悬挂系统,轨道被视为弹性欧拉梁,并考虑了磁悬浮车辆的控制系统性能。数值分析结果表明:梁的最大变形的计算值为1.5mm,试验值为1.6mm,车体的垂向加速度仿真结果与试验结果基本一致,利用仿真模型能较准确地预测耦合系统的动力学性能。

常导磁浮列车动态磁轨关系研究

研究常导磁浮列车动态磁轨关系,从车辆-轨道耦合动力学思想出发,结合特定悬浮控制规律,建立考虑微小波动时的单磁铁动态悬浮控制数学模型;通过悬浮控制的磁浮车辆-轨道的相互作用研究具有特定悬浮控制系统的车辆在运行过程中的动态磁轨关系。研究结果表明:间隙反馈系数对悬浮系统的初始状态影响很小;当系统受到外界激扰时,间隙反馈系数对悬浮状态影响变大,随着间隙反馈系数的增大,悬浮间隙的动态变化趋于稳定;车辆在桥梁上运行时,悬浮间隙一直处于波动状态,且车辆在进、出桥梁时波动最大,动态悬浮间隙与车速成正比,车辆载重与桥梁振动幅度成正比。当车速超过250km/h后,动态悬浮间隙受车速的影响迅速增大,磁轨关系的线圈电流、电磁悬浮力的变化与悬浮间隙变化基本一致。

磁浮车辆/高架桥垂向耦合动力学研究

磁浮铁路为了实现高速客运 ,大量采用了封闭式高架线路。在德国 Emsland磁浮试验线上 ,采用了混凝土简支梁和钢结构两跨连续梁作为高架线路的主要形式。本文以这两种结构形式为例建立了磁浮铁路车辆 /高架桥垂向耦合模型 ,分别对不同材料和结构形式支承梁以及不同车速时车桥耦合动力响应进行了仿真计算 ,得到两种支承梁结构下系统动力响应特征及车速对耦合系统动力影响规律 ,为磁浮高架线路设计和进一步的系统优化提供了理论依据。文末以我国青城山磁浮线现有的一组基本数据 。