To improve EMS high-speed maglev vehicle adaptability to diverse terrains, curve negotiation performance on sharp-radius tracks requires thorough investigation. Previous research has not adequately characterized the dynamic performance of these vehicles under such conditions. This study first conducts dynamic testing at discrete speed levels on Tongji University's maglev test line to identify guidance performance characteristics on a sharp curve. Experimental data subsequently validate the reliability of the co-simulation model. Then, the comprehensive responses of the full-vehicle are analyzed. Finally, a parametric study is performed, and the optimal parameter combination is selected. Key findings demonstrate that guidance offset exhibits speed invariance on a sharp curve. However, the outermost control current of the end guidance electromagnet increases proportionally with vehicle speed at approximately 3.5% per 10 km/h increment. Additionally, proportional feedback in the guidance control system exerts greater influence on curve negotiation performance than other examined parameters. It is also noted that excessive secondary bumpstop clearance significantly degrades ride quality during negotiation of sharp curves.

Electro-magnetic Suspension (EMS) high-speed maglev is currently the fastest ground transportation system, and its dynamic issues remain a research hotspot, though experimental studies are scarce. Focusing on the EMS highspeed maglev vehicle developed in China, vehicle-track-guideway coupled vibration tests were conducted. Dynamic data from the vehicle, levitation/guidance systems, track, and guideway under variable-speed conditions were collected, followed by data processing and dynamic performance evaluation. The research results indicate: the vibration acceleration of the vehicle's multi-body system decays progressively, and the car-body Sperling index reaches an excellent level; the dynamics response of the vehicle after entering the R400 m curve from the straight line increase significantly, with the fluctuation range of the levitation gap exceeds +/- 4 mm during curve negotiation, and the guidance gap shifts by 5-8 mm; the maximum dynamic deflections at mid-span of the guideway, along with the vertical/lateral vibration accelerations of the track and guideway, are all within safe limits, and the vibration frequencies correspond to their modal frequencies.

The 600 km/h high-speed maglev transportation system represents the fastest existing ground transportation technology. As the electromagnetic suspension (EMS) type high-speed maglev system currently lacks the conditions for full-speed testing, this study conducted low-speed dynamic experiments to investigate the vibration transmission characteristics within the vehicle system. First, time-domain track irregularity data were derived from the low-speed experimental data. Subsequently, time-frequency analysis was performed on the dynamic responses at different vehicle locations, and the coherence between track irregularities and these responses was investigated. Finally, the vibration transmission characteristics were analyzed using the vibration acceleration level difference method. The results indicate that the energy of the measured track irregularities is concentrated within the low-frequency range below 15 Hz. Within the 0 similar to 13.67 Hz low-frequency range, track irregularities constitute the primary influencing factor on the vehicle's dynamic responses. The vibration reduction performance of the primary suspension is relatively weak. In contrast, the flexible levitation frame and air spring exhibit frequency-dependent vibration reduction effectiveness across different bands, while the bolster, hanger rod, and auxiliary floor demonstrate effective vibration isolation and reduction performance across the entire frequency range. These findings provide support for the optimization of suspension systems in high-speed maglev vehicles.

Maglev vehicles operate via non-contact levitation generated by electromagnetic forces, wherein track irregularities constitute a critical factor inducing variations in suspension system stability and vehicle vibration. Currently, dedicated field measurement methodologies and instrumentation for maglev track irregularities remain scarce; consequently, dynamic analyses frequently rely on equivalent treatments using spectra derived from other track types. Addressing this gap, this study proposes a novel track irregularity measurement method tailored to maglev track characteristics and grounded in the chord measurement principle. Furthermore, an automated inspection trolley capable of autonomous operation and data acquisition was developed. Field measurements were conducted on the Qingyuan maglev line in China using this apparatus. Through processes including filtering and reconstruction of the acquired data, authentic track irregularities were restored. Modal decomposition based on CEEMDAN revealed that the wavelength distribution of irregularities correlates closely with structural characteristic lengths, such as those of sleepers and track panels. Specifically, the dominant wavelength range for vertical profile irregularities was identified as 1.23–30.62 m, while that for alignment irregularities ranged from 1.31–25.66 m. To address the paucity of power spectral density (PSD) functions for maglev tracks, the quantile spectral characteristics of the measured data were comparatively analyzed. The 50% percentile spectrum was selected for PSD function fitting, yielding a goodness-of-fit approaching unity. This result indicates that the constructed PSD function effectively characterizes the actual state of track irregularities.

The traction device serves as the mechanical structure responsible for transmitting longitudinal loads between the car-body and the running gear. However, during collision impacts in maglev vehicles, the structural integrity of this device is compromised, with bolts pull-out failure occurred during the engineering practice. To enhance the connection reliability, this study analyzed its stress states under various longitudinal impact scenarios. A finite element model of the maglev vehicle was established to compute transient dynamic responses during collisions, with a specific focus on the failure mechanisms of the traction device, particularly the connection bolts. Furthermore, an innovative structure featuring bidirectional buffering capabilities was proposed to protect the bolts. Simulation-based results indicate that the inclination angle of the traction rod generates a vertical component force under longitudinal impact, which exerts a tensile load on the connecting bolts; this mechanism is identified as the critical factor leading to pull-out failures. The bolt connection failure process comprises four distinct stages: stability, loading, front-end damage, and rear-end damage, and bolt pull-out occurred across all four traction devices during collision events. Extending the length of the traction rod reduces the inclination angle, thereby improving the stress distribution, while the bidirectional buffering structure further absorbs a portion of the longitudinal impact energy. Under the comparative calculation conditions and within the limited mileage tracking inspection in the project, no connection failure issues have occurred again.

Maglev vehicles operate through non-contact levitation via electromagnetic forces, with track irregularities serving as a critical factor affecting levitation stability and vehicle vibration. Currently, field measurements of maglev track irregularities remain scarce, often necessitating the use of alternative track spectrum as equivalents for dynamic analysis. This work proposes an automated track inspection methodology capable of real-time data acquisition, which was implemented on the Qingyuan Maglev Line in China. Through data processing, filtering, and signal reconstruction, the true track irregularities were recovered. Mode decomposition based on CEEMDAN revealed that the wavelength components of irregularities align closely with structural periodicities such as sleepers and track panels. Specifically, the primary wavelength range for height irregularity spans 1.23–30.62 m, while for alignment irregularity it is 1.31–25.66 m. Furthermore, power spectral density (PSD) analysis of the reconstructed spatial irregularities was performed, and percentile-based spectral characteristics were extracted and compared. The 50% percentile spectrum was selected for PSD fitting, with a coefficient of determination (R2) approached 1, indicating that the constructed PSD function effectively represents the characteristics of the actual maglev track irregularities.

This paper investigates the influence of bridge type on vehicle-bridge coupled vibration in medium- and low-speed maglev systems (up to 160 km/h). Firstly, a multi-body dynamical model of the vehicle-incorporating active levitation and passive guidance—was established and a carbody modal analysis was conducted; finite element models were then developed and modal analyses were conducted for three bridge types: 25 m simply supported beam, 2×25 m continuous, and 3×25 m continuous beams. Next, a vehicle-bridge coupled dynamical model was developed in UM, which integrates the vehicle, suspension control, guideway, and bridge subsystems. Using measured track irregularities as excitation inputs, simulations were conducted for a three-car formation passing over bridges of the given types at speeds ranging from 20 to 160 km/h. Simulation results show that all dynamic responses indicators for the subsystems meet the relevant specification requirements across the entire speed range. Specifically, suspension modes are identified as the dominant factor governing carbody vibration, indicating a minor effect from bridge types on vehicle response. However, vehicle dynamic responses in the multi-span continuous beams scenario are better compared with the single-span simply supported beams scenario. Bridge responses vary significantly across bridge types: some dynamic response indicators are more pronounced in the 25 m simply supported beam scenario than in the multi-span continuous beams scenario. As vehicle speed increases, response amplitudes rise. Low-frequency bridge vibration is susceptible to periodic resonance excitation when the vehicle operates at 100 km/h and 140 km/h, and both higher speeds and larger track irregularities intensify the coupled vibration. Vehicle dynamic performance is better in the multi-span continuous beams scenario, with the maximum carbody vertical acceleration observed at 0.49 m/s², the maximum Sperling index at 1.81, levitation gap fluctuations not exceeding 4 mm, and the maximum mid-span vertical deflection of L/11211 for the bridge, all of which satisfy the relevant specification requirements.

To minimize the construction cost of track beam and enhance the dynamic performance of the magnetic suspension system, a simplified coupled vibration model of the electromagnet-track beam-vehicle body was established. Initially, by defining a Lyapunov function to represent the quadratic performance index of the maglev system under parameter perturbation, the controller design problem for the closed-loop system was transformed into an existence problem of linear matrix inequality (LMI) solutions. Consequently, a state-feedback cost-preserving robust controller for a flexible track beam was designed. Subsequently, the impact of the suspension controller on the dynamic characteristics of the flexible track beam, both with and without considering parameter perturbation, was compared and analyzed. Furthermore, the robustness, high-frequency suppression, and low-frequency following characteristics of the LMI-based controller were evaluated. Finally, the influence of two distinct state feedback controllers on the dynamic characteristics of the flexible track beam across different frequency bands was analyzed. Correlation analysis revealed that accounting for parameter perturbation can improve the suspension and dynamic characteristics of the suspension controller. When the system experiences parameter perturbation, the LMI-based suspension controller can achieve stable suspension on the flexible track beam while demonstrating strong robustness, high-frequency suppression, and low-frequency following capabilities. On the flexible beam, controllers with different state feedback exhibit varying dynamic characteristics in different vibration frequency segments of the track beam. Specifically, reducing the feedback state variables in the low-frequency band and increasing them in the high-frequency band can appropriately improve the system’s dynamic characteristics.

The non-contact support form of maglev trains provides them with excellent vibration isolation capabilities. However, the method of maintaining stable levitation through active feedback makes maglev trains prone to self-excited vibrations and even levitation failure on lightweight track beams. Most current studies on levitation self-excitation are conducted using multibody dynamics modeling and simulation. Although this approach offers good explanatory power for specific issues related to particular train models, its conclusions are difficult to generalize. Moreover, due to the inclusion of algebraic constraints and partial differential equations in the models, qualitative analysis of the mathematical models becomes challenging, which is disadvantageous for studying the conditions of self-excited vibrations. This study proposes a compact modeling method coupling multiphysics. By making reasonable assumptions and simplifications, we tightly integrate the mechanical, electromagnetic, control systems involved in the maglev train levitation system with the beam system. The resulting model, which can explain the causes of self-excited vibrations of maglev trains on lightweight track beams, is represented by a finite-dimensional set of ordinary differential equations that do not include algebraic constraints and partial differential equations. This characteristic enables the applicability of classical stability analysis techniques. Finally, a numerical example is provided to illustrate the use of the model and to explain why maglev trains can maintain stable levitation over mainline beams but fail to sustain stable static levitation over turnout tracks.

The Electro magnetic suspension (EMS) maglev train uses active control to achieve levitation stability, and the eddy current effect of the levitation electromagnet can make it difficult to adjust the control parameters of EMS maglev train, even affecting the levitation stability of EMS maglev train. Aiming at the control parameters of EMS maglev train under eddy current effect, an analytical expression of the levitation force considering eddy current effect was derived, and a single electromagnet levitation model was established. The influence of eddy current effect in the stability of open-loop levitation system was compared and analyzed. A fitting levitation control parameter was determined through a single levitation frame bench test, and the Simulink model of a single levitation frame was established. The different levitation control parameters effects considering eddy current effects at 200 km/h was studied comparatively, and a BP-PID adaptive controller was designed to adjust the controller parameters of EMS maglev train. The research results showed that the proposed BP-PID controller can effectively adjust control parameters to achieve effective compensation and optimization of the balance working point of the air gap caused by eddy current effect.

To study the lateral stability of the electromagnet in a passive-guided maglev system, a non-autonomous nonlinear differential equation that retains the lateral motion characteristics of the electromagnet was derived from reasonable assumptions. The stability at the equilibrium point of the equation can be determined by whether the eigenvalues of the coefficient matrix of the Poincaré map of the linearized equation are within the unit circle centered at the origin. This process yields the linear stability boundaries regarding the parameters of the electromagnet's lateral motion equation. It was discovered through the positions where the eigenvalues cross the unit circle at the time of linear instability that the Poincaré map of the equation may undergo flip or pitchfork bifurcation when crossing from different linear stability boundaries, which results in vibration orbits with varying symmetries during lateral instability. An experiment on the influence of vertical excitation on lateral stability was conducted using a levitation frame vibration experimental bench. The experiment demonstrated that the theoretical analysis on stability and orbit symmetry is reliable.

The stability of the suspension is a key challenge for the application and promotion of electromagnetic suspension technology, especially when it operates in conjunction with a flexible structure, which significantly increases the system's complexity. This paper abstracts the characteristics of the coupling conditions between an electromagnetic suspension system and a flexible structure and designs and constructs an experimental apparatus that includes an electromagnet and a simulated flexible structure with adjustable stiffness and inertia. Based on the Lyapunov method, the central manifold theorem, and the Poincaré method, the stability of the electromagnetic suspension system and the conditions for Hopf bifurcations are derived. Finally, through reasonable experimental design and data analysis, the correctness of the theoretical analysis conclusions is validated, providing references for the engineering applications of electromagnetic suspension systems.

Track irregularities are the main factors causing changes in suspension stability and vibrations in EMS (Electro-magnetic Suspension) maglev trains. Due to the scarcity of actual measurement data on EMS maglev track irregularities, this paper utilizes the principles of the mid-chord offset method to develop a track irregularity detector with a 1-m test chord length. Tests were conducted on the maglev line in Qingyuan, Guangdong. Based on the "using small to predict large" algorithm, data simulating a 3-m test chord length were output. The experimental data were processed to remove trend items and outliers, and an inverse filter was designed to counteract the amplitude gain error of the mid-chord offset method, obtaining accurate data on vertical and lateral track irregularities. The results show that the amplitude and power spectral density (PSD) fluctuations of track irregularities on the left and right rails of the measured line section are similar, with height irregularities of 2.5-3 mm and alignment irregularities of 1-1.5 mm. Periodic wavelength components related to the longitudinal spacing of sleepers, rail length, and beam span, such as 1.2 m, 6.5 m, 12.5 m, and 25 m, are evident, highlighting the need for enhanced inspection and maintenance of these structural components in engineering projects.

A comparative study was conducted on Levitation Frame with Mid-set Air Spring (LFMAS) and Levitation Frame with End-set Air Spring (LFEAS). First of all, the work done by air spring force and by track excitation on two levitation frames were analysed, respectively, and the mechanism of the low dynamic interaction of LFMAS with guideway was explained theoretically; then, dynamics simulation and coupled vibration test on LFEAS and LFMAS were carried out using coupled vibration test bench of single levitation frame. Theoretical equations show that both the work done by the air spring forces and by track excitation on LFMAS are less than those on LFEAS under the same vibration condition, demonstrating that LFMAS has better levitation stability than LFEAS. Simulation and test results show that the fluctuation of levitation gap as well as the vibration acceleration of track beam platform, levitation frame and car-body of LFMAS are all smaller than those of LFEAS; with the increase of sine excitation frequency or vehicle speed, the superiority of LFMAS in dynamics performance is more obvious.

The medium–low speed maglev train was simplified as moving loads models, based on the theoretical solution for vibrations of the simply supported beam under moving loads, resonance and cancellation conditions were derived. A medium–low speed maglev train of 3-railcars formation passing through a 25 m simply supported beam was taken as an example, with its vibration resonance and cancellation phenomena analyzed when the moving loads with different characteristic lengths pass through the beam. Research results show that: different characteristic lengths correspond to different resonance and cancellation speeds; when resonance occurs, the dynamic responses of the moving loads acting successively on the beam are same in phase, and the free vibrations of the beam are amplified after superimposed; when cancellation occurs, the dynamic responses of the moving loads acting on the beam are opposite in phase; thus, the free vibrations of the beam cancel to null.

The EMS (Electromagnetic Suspension) high-speed maglev train employs electromagnetic force as the primary means for both levitation and guidance The safety and comfort when the train transitions from a straight line to a small radius curve need in-depth research. Taking a small radius curve of 400 m as an example, this paper first theoretically calculates the curve and transition curve lengths, cross slope angles, and the safe passing speed of the train. Considering the intricate active suspension and guidance control system, a precise dynamic model of the EMS high-speed maglev train is constructed, calibrated with theoretical line condition parameters for enhanced academic rigor. The kinematic posture and vibrational responses of the car-body, secondary suspension, suspension frame, and associated components are comprehensively simulated and analyzed, with a critical evaluation of the train's curve traversal performance. The results show that, according to the theoretical calculation of R400 m small radius curve parameters, when the train passes at the speed of 88.64 km/h, the roll angels of the car-body and suspension frame are within the safe range, the fluctuation of levitation gap is not exceed 4 mm, and the fluctuation of guidance gap is close to 6 mm.

Suspension frame components of medium and low speed maglev train are mainly connected by bolts. When suspension of train fails to fall, bolts at connection positions between parking brake skid and corbel are subject to larger shear action, and there is a structural safety risk. Here, the finite element model of suspension frame was established by using the software HyperMesh considering bolt connection and contact relations at parking brake skid position. Dropping processes of suspension frame under different speeds were simulated based on ANSYS/LS-DYNA. Contact force fluctuations of various contact pairs were calculated. Stress changes and distribution laws of connection bolts, skid keys, skid mounting base and corbel were analyzed. The results showed that contact forces of various contact pairs reach peak values at the moment of drop impact, and then decreases in process of small fluctuation; when suspension frame in motion state falls, various contact forces are much larger than those under the working condition of static vehicle from suspension to dropping, stresses of connection bolts increase significantly, and maximum equivalent stresses of skid key, skid, and skid mounting base exceed yield limit of material to have structural safety risks, and require timely inspection in project.

EMS（Electro-magnetic Suspension）型中低速磁浮列车依靠主动控制的电磁力悬浮，并利用短定子直线感应电机牵引，悬浮架是承载列车运行的关键子系统。围绕国内外EMS型中低速磁浮列车应用案例，介绍了（悬挂）端置式悬浮架、（悬挂）中置式悬浮架的技术方案和特征，总结了主要技术指标。结合悬浮架技术研究、发展现状，讨论了磁-轨作用关系、运动解耦能力、动力学性能、结构强度以及悬浮冗余设计五大研究方向，通过对研究内容梳理和总结，归纳了现有前沿科学问题和工程技术挑战：一是轨距亟需统一；二是动态磁轨关系研究欠缺；三是悬浮架横向动力学有待研究；四是悬浮架疲劳强度分析及试验不足；五是悬浮架机械结构冗余设计方案较少。

为抑制EMS型磁浮车辆-轨道梁耦合振动,建立了车辆-悬浮控制系统-轨道梁-动力吸振器垂向耦合动力学模型.以考虑轨道梁1阶振动模态和2阶振动模态为算例,分别设计了单动力吸振器和多重动力吸振器,并基于扩展定点理论与频率传递函数分析了2种动力吸振器方案的最佳参数,进而对不同质量比的动力吸振器进行了动力学仿真对比.通过研究可以得出以下结论:当激扰力频率接近轨道梁固有频率时,轨道梁因共振而达到最大动态响应,此时动力吸振器的振动加速度抑制效果最好,接近60％;质量比过大时容易产生负控制,而过小的质量比会使得动力吸振器的制振效果不明显;多重动力吸振器质量分布均匀,制振效果优于单动力吸振器,并且负控制小于单动力吸振器.

煤炭、矿石等散装物料普遍存在最后"十公里"的运输问题.本文提出了一种由永磁同步直线电机驱动的磁动力物料运输列车方案,介绍了永磁同步直线电机的理论模型,基于电机推力要求进行了电机参数设计,利用有限元软件校核了Halbach永磁阵列磁场强度.基于SIMPACK多体动力学软件建立了磁动力物料运输列车的动力学模型,分析了列车直线安全性和曲线安全性等动力学指标.研究结果表明:磁动力物料运输列车设计方案合理可行,动力学性能满足使用要求,能够为散装物料的短距离运输提供一种解决思路.