High-temperature superconducting (HTS) pinning maglev systems offer numerous advantages, including simple structure, passive stability, inherent absence of magnetic resistance in the forward direction, low noise, and high energy efficiency, making them highly promising for future applications in the field of rail transportation. Presently, most HTS maglev pinning systems utilize linear motors as their driving systems. While suitable for high-speed environments, this driving method is costly and space-consuming. Therefore, our group proposes a low-cost and structurally simple driving method for low-speed environments by integrating permanent magnet electrodynamic wheels (PMEDW) with HTS pinning maglev systems and investigating its dynamic performance. The dynamic performance of this system is studied using electromechanical coupling simulation. A finite element simulation model of the PMEDW is developed in the Maxwell 3D module of ANSYS Electronics to solve for electromagnetic forces. Based on this, a dynamic model using the multibody dynamics software Universal Mechanism (UM) is established to analyze the dynamic performance of a small-scale HTS maglev vehicle during the driving phase due to misalignment of the PMEDW on both sides and asynchronous rotation speeds. The results indicate that controlling the speed difference between the two PMEDWs and the installation error within the allowable range enables good dynamic performance of the small-scale HTS maglev vehicle, achieving safe and stable operation during the driving phase. This study provides technical references for the engineering application of PMEDW driving systems in HTS maglev systems.

Driven by the growing demand for clean and high-velocity transportation, maglev car systems have emerged as promising solutions. Precise velocity control is crucial for the safe and stable operation of maglev cars. However, strong nonlinearities and underdamped dynamics of these systems make accurate modeling difficult, which limits the performance of traditional model-based controllers. Therefore, research in this area remains limited. While Model-Free Adaptive Control (MFAC) offers a potential solution, standard algorithms with fixed parameters that struggle to balance response velocity and stability. To overcome these limitations, this paper proposes an MFAC framework integrated with error gain scheduling (EGS). The EGS dynamically adjusts the controller's parameters based on real-time tracking error regions, thereby mitigating the trade-off between transient response rate and overshoot. The MFAC-EGS scheme preserves low computational complexity and real-time adaptability, requiring neither a precise model nor extensive offline training. The primary contributions of this work include: 1) A velocity control scheme for maglev cars is developed to ensure stable velocity regulation under complex conditions, which is essential for operational safety and stability; 2) A data-driven MFAC-EGS paradigm is established, which enhances MFAC robustness against disturbances without increasing structural complexity; 3) Experimental results demonstrate that the maglev car velocity control function is achieved under various controllers, among which MFAC-EGS shows the superior control performance. Specifically, the proposed method reduces the root mean square error (RMSE) by 20.9% in steady-state tracking and 22.9% under disturbed conditions. It also achieves reductions of 50.5% and 21.5% for triangular and square-wave signals, respectively, alongside faster response and lower overshoot. This work offers valuable insights into the future high-speed operation of maglev cars. Note to Practitioners-This work addresses the engineering challenge of achieving precise and robust velocity control in magnetic levitation (maglev) vehicles, which are characterized by severe nonlinearities and underdamped dynamics. Traditional model-based controllers often struggle in such scenarios due to the difficulty and cost of obtaining accurate system models. The primary application of this paper is on high-velocity maglev systems, where operational safety, ride comfort, and energy efficiency are critical. This paper proposes a data-driven model-free adaptive control strategy with error-gain scheduling (MFAC-EGS). The primary advantage of this approach is that it circumvents the need for analytical modeling and offline training, significantly reducing implementation overhead. By dynamically scheduling control parameters based on real-time error zones, the algorithm significantly mitigates the inherent trade-off between fast transient response and overshoot suppression. Experimental results on a maglev platform demonstrate that MFAC-EGS significantly minimizes tracking errors and enhances disturbance rejection. This suggests a deployable, low-complexity solution for high-precision motion control. A limitation of this study is that it is currently validated on a scaled experimental platform. Therefore, future research will focus on extending this framework to full-scale, high-speed prototypes to further assess its scalability under varying communication and environmental conditions. The proposed method is broadly applicable to other industrial systems with distinct operational stages, such as autonomous aerial vehicles and intelligent vehicles control.

High-temperature superconducting (HTS) magnetic levitation (maglev) offers a promising solution for urban and high-speed transport due to its self-stabilizing levitation and negligible magnetic drag. This paper introduces a novel V-shaped permanent magnet guideway (PMG) that achieves stronger magnetic-flux concentration than conventional flat PMGs, enabling reduced rare-earth magnet usage while enhancing both lift and lateral guidance performance. A validated finite element model is used to characterize the electromagnetic forces, which are then incorporated into a dynamic model of an HTS maglev vehicle, including a carbody, five bogies, ten air springs, and sixty cryostat-mounted HTS bulk modules. Dynamic simulations across speeds of 60-160 km/h show enhanced levitation efficiency, improved lateral stability, and acceptable ride comfort and vibration. These results demonstrate the feasibility of the V-shaped PMG concept and provide both theoretical guidance and engineering evidence for its application in future HTS pinning maglev transportation systems.

To investigate the blocking effects and acoustic reflections in tunnels on the unsteady flow field and aerodynamic noise sources of rapid metro trains, this study employs a hybrid improved delayed detached eddy simulation and acoustic perturbation equations method to simulate the near-field noise of a 1/20 scale model metro train within a tunnel. The numerical approach is validated against wind tunnel experiments conducted with a high-speed train scale model. Results show that the blocking effect significantly increases the overall flow speed and elevates the train surface's total turbulent pressure and power levels, with the highest value reaching 132.67 dB at the head car. Additionally, three cases are studied: a tunnel with fully reflective walls, a tunnel with fully absorptive walls, and open-air conditions. Results demonstrate that the blocking effect primarily raises the overall total sound pressure level, while acoustic reflection further amplifies the sound and causes the sources to concentrate toward the middle of the train. The majority of the difference in sound power level between the tunnel and open air is attributed to the blocking effect, which accounts for up to 68.28%. Frequency spectra of sound pressure analysis reveal five peaks in the tunnel with fully reflective walls-260, 500, 850, 2490, and 3430 Hz-where Bogies 3 and 5 exhibit the highest power spectral density values of 124.55 and 124.91 dB/Hz, respectively. These findings provide valuable insights for future noise control strategies on rapid metro trains.

In practical research of high-temperature superconducting (HTS) maglev, a compulsory centering alignment operation between the superconducting levitator and permanent magnet guideway (PMG) is completed before field cooling (FC) process. However, errors in installation, positioning, and machining may lead to an eccentric state between the superconducting levitator and PMG before the FC process, which essentially means the geometric center of the internal HTS bulks is eccentric from that of the PMG. Therefore, this study investigates the effects of eccentric field cooling (EFC) on the levitation and guidance performance of HTS maglev. Specifically, a Halbach-type PMG is employed, and the eccentric displacement (ED) of bulks is set before FC process. Then during the levitation process, lateral displacement (LD) between bulks and PMG is applied to generate the guidance force. Results show that the EFC can adversely affect the levitation force, and this detrimental effect intensifies with increasing ED. During the LD process, when LD and ED are in the same direction, the reduction in levitation force increases with higher LD; conversely, when LD and ED are in opposite directions, the reduction decreases with increasing LD. Regarding the guidance force, at the initial of LD, appropriate EFC can enhance it, but excessive ED or LD values will negatively impact guidance force. These findings suggest that, in applications requiring high levitation performance, strict centering alignment operation before FC is essential. In contrast, for systems prioritizing guidance performance, appropriate applied EFC may be an effective optimization strategy.

High-temperature superconducting (HTS) maglev systems, as promising transportation solutions, have garnered growing attention in maglev transportation due to their inherent passive self-stability. To leverage this advantage, this paper pro-poses a compact propulsion system featuring a contactless power-train with a permanent magnet electrodynamic in-wheel motor (PMEIM). First, analytical modelling is employed to characterize the external magnetic field of the PMEIM, and its characteristics under multiple operating conditions are derived via coordinate transformation. Subsequently, the eddy current model of the secondary conductor plate is established, and its reflected mag-netic field is solved. Based on this, the electromagnetic force model of the PMEIM powertrain is developed in accordance with the magnetic charge theory, and the corresponding mechanical characteristics are determined. Next, the PMEIM design is con-ducted, with its load characteristics and transient response eval-uated by electromagnetic analysis and co-simulation. Finally, a small-scale prototype is fabricated and tested. Results indicate that theoretical predictions are in close agreement with the ex-perimental measurements, with the measured propulsion and guidance forces being 12.70 N and 41.14 N, respectively, under rated operating conditions. The integrated PMEIM configuration enables contactless force and torque transmission, demonstrating potential as a compact, flexible, and cost-effective propulsion solution for HTS maglev systems.

High-temperature superconducting (HTS) pinning maglev trains exhibit a reduction in levitation force when excited by high-frequency magnetic fields. The representative solution is to introduce an electromagnetic compensation subsystem (EMCS). Under time-varying disturbances, the lateral-vertical coupled vibration of the HTS-EMCS hybrid system demonstrates strong nonlinearity. Upon excitation at sensitive frequencies, primary resonance and other resonant responses are induced, thereby jeopardizing the train’s operational safety. Accordingly, this study employs a multi-scale method to investigate the mechanism underlying the nonlinear lateral-vertical coupled resonance behavior of the HTS-EMCS system. Firstly, the dynamic model is established based on experimental data. Subsequently, second-order analytical solutions for the nonlinear lateral and vertical free vibrations are derived, and the dynamic characteristics are examined using phase trajectory analysis. Furthermore, the dynamic behavior of primary and non-primary resonances under forced excitation is investigated. Finally, the conclusion is verified through experiments. Results indicate that EMCS can effectively enhance the lateral damping of systems. This is a significant improvement over existing weak damping systems, effectively suppressing multi-modal resonance and reducing the quasi-periodic torus. In addition, EMCS can soften the lateral-vertical coupling degree. This study provides a reference for improving the safety and engineering application of the HTS maglev train.

High-temperature superconducting (HTS) maglev systems are highly promising for next-generation transportation; however, the design optimization of the permanent magnet guideway (PMG) is severely bottlenecked by the computationally time-consuming finite element method (FEM) required to resolve the strongly flux-pinning hysteresis. To bridge this gap, this paper proposes a Long Short-Term Memory (LSTM)-based surrogate framework that replaces FEM in the optimization loop for rapid multi-objective PMG design under hysteretic constraints. Built upon an experimentally validated H-formulation FEM model, a Maximin Latin Hypercube dataset is generated over a 6-dimensional geometric-operational design space. To address hysteretic multi-valuedness, physics-aware preprocessing encodes the motion phase and direction. By capturing path-dependent sequential patterns, the LSTM surrogate achieves high accuracy (R2 > 0.999 for levitation force) and outperforms XGBoost (R2 > 0.96), GRU, and Transformer baselines. Furthermore, coupling this surrogate with NSGA-II, which balances Pareto ranking and diversity preservation, enables constrained PMG design optimization. The optimized full-scale design identifies a feasible 2.1% reduction in PMG cross-sectional area while satisfying both levitation and guidance force requirements. A scaled prototype experiment further validates the cost-optimized design logic. This work provides a practical data-driven framework for efficiently optimizing complex engineering systems with strong hysteresis effects.

This paper investigates the nonlinear dynamics of the High-Temperature Superconducting (HTS) pinning magnetic levitation (MAGLEV) transit system under development at the University of L'Aquila. Due to its inherently weak damping characteristics, the MAGLEV system is particularly susceptible to external disturbances, such as mechanical or magnetic irregularities along the guideway. To analytically characterize its complex nonlinear dynamics, a simplified nonlinear single-degree-of-freedom model is developed, and the Multiple Scales Method (MSM) is employed as a solution technique. This approach enables the evaluation of how key design parameters influence the system's dynamic response. The analysis highlights the emergence of both primary and secondary resonances, which arise depending on system parameters and the nonlinear nature of the levitation force, potentially impacting not only performance but also stability. Finally, the analytical findings are validated against benchmark solutions obtained through direct numerical integration of the system's nonlinear equation of motion.

Robust control of active magnetic bearing (AMB) systems has attracted significant attention due to its ability to effectively address modeling uncertainties and enhance system robustness. However, the design of robust controllers is often time-consuming, non-intuitive, and typically dependent on trial-and-error tuning. To overcome this limitation, this paper proposes a new optimization-based framework for robust controller design. By introducing disk margin (DM) as a robustness objective together with dynamic performance objectives, the weight-function design process is transformed into an intuitive procedure for balancing the trade-off between robustness and performance. The nominal model is obtained via frequency-domain system identification method. The structures of the three weighting functions in the robust control framework are determined. Seven weighting-function parameters are then selected as optimization variables, and the necessary constraints are imposed according to the requirements of robust control and the AMB system. The robust controller is synthesized by directly selecting the weighting-function parameters from the Pareto-optimal solution set and is further validated experimentally. The results show that the designed robust controller stabilizes the system well and reduces the vibration amplitude at the first flexible mode by approximately 70% compared with the benchmark controller, thus demonstrating the effectiveness of the proposed methodology.

High-temperature superconducting (HTS) maglev trains utilize the unique flux pinning effect of HTS bulks to achieve levitation and guidance, the core of which lies in the magnetic-force-thermal properties of the HTS bulks. In this paper, based on a 5 T superconducting magnet, we build an experimental platform for mixed external magnetic fields, as well as a magnetic-force-thermal coupling test system. The system is equipped with an additional horizontal coil (AHC), which enables independent adjustment of the vertical and horizontal magnetic field components under a high background magnetic field. The effects of magnetic field characteristics on the levitation force (LF) of HTS bulks under high background field are investigated, and the relationship between the horizontal magnetic field fluctuation ΔBx and the AC loss characteristics of HTS bulks is also explored. It is found that after the saturation of the vertical magnetic field variation ΔBz, increasing the Bx can bring up to more than 50% enhancement of LF. Moreover, LF attenuation and temperature rise in the HTS bulk become increasingly significant with a larger ΔBx amplitude, a frequency near 200 Hz, or a square wave excitation. In this process, the temperature rise due to AC losses is significantly larger in the bulk growth section region (GSR) than at the growth section boundary (GSB). The results of this study fill the gap of the magnetic-force-thermal test of HTS bulks under mixed external magnetic field of superconducting magnet, point out the direction of optimization of the LF from the aspect of magnetic field structure, and further clarify the external factors affecting the magnetic-thermal stability of HTS bulks.

Superconducting Pinning Maglev (SPM) and Permanent Magnet Maglev (PMM) systems generate levitation force using permanent magnet tracks, offering advantages such as simple structure and low energy consumption. However, accurate measurement of key state parameters-namely the levitation gap and lateral deviation-remains challenging due to strong magnetic fields, non-magnetic protective layers, and environmental disturbances near the track surface. To address this issue, this paper proposes a non-contact measurement method based on magnetic-field inversion for real-time estimation of levitation gap and lateral deviation. A magnetic field-displacement conversion model is established using a surface-current approach, and a multi-point Hall sensor array is employed to acquire magnetic field signals above a Halbach-type permanent magnet track. An error-minimization inversion algorithm is then used to infer the corresponding displacement parameters. Static calibration experiments demonstrate that, under the tested conditions, the proposed method achieves a maximum measurement error of 0.11 mm, with an average error of approximately 0.04 mm, satisfying typical engineering accuracy requirements. Dynamic running tests conducted at speeds ranging from 10 km/h to 25 km/ h further verify that the method can stably track levitation gap and lateral deviation variations in real time within the validated speed range. The results indicate that the proposed approach provides an effective and practical solution for non-contact state monitoring of maglev systems employing permanent magnet tracks.

High-temperature superconducting (HTS) pinning maglev technology is considered promising for high-speed transportation due to its self-stabilizing characteristics, and it has been widely studied worldwide. In high-speed engineering applications, safety is a primary concern, largely dependent on the reliable flux-pinning capability of the onboard superconductors. This article proposes a noncontact, nondestructive, and easy-to-implement real-time monitoring method for assessing the flux-pinning state of HTS bulks onboard maglev vehicles, based on the antisymmetric property of null-flux coils. The configuration, working principle, and mathematical model of the method are established, along with a coil geometry optimization strategy and a tailored low-frequency, narrowband filtering circuit. An experimental setup is then built based on the optimized parameters, and a series of tests are performed to the method's feasibility. Furthermore, the effectiveness of the resonance-frequency-based filtering circuit in enhancing signal extraction is analyzed, and theoretical predictions of the relationship between the voltage signal and factors such as displacement, working height (WH), and degradation level are validated experimentally. This study provides a comprehensive investigation from concept to validation and demonstrates strong potential for real-time safety monitoring in HTS maglev systems. It can also offer useful insights for other superconducting or maglev monitoring applications.

For high-speed operation of the high-temperature superconducting pinning (HTSP) maglev, adopting a coreless permanent magnet linear synchronous motor as the propulsion system ensures sufficient thrust while maintaining low normal force, thereby reducing the additional load imposed on the levitation system. In this study, based on the linear motor adopted in the HTSP maglev high-speed engineering prototype vehicle and test line, a three-dimensional finite element (FE) model is established to analyze the characteristics of the air-gap magnetic field distribution. The electromagnetic force of coreless and iron-core designs is compared. Subsequently, a two-dimensional analytical model is developed and further refined by incorporating the lateral end effect. Based on the three-dimensional magnetic field distribution obtained from the FE analysis, the analytical model is extended to a quasi-three-dimensional model. By comparing the analytical and FE models, the validity of the proposed analytical model is verified. On this basis, the influence of the air-gap length and the amplitude of the stator current on the electromagnetic force is investigated. The proposed analytical model is highly efficient in electromagnetic force calculation, providing a foundation for electromechanical coupling dynamics simulation of the levitation and propulsion systems in HTSP maglev.

Abstract Superconductivity was discovered more than a century ago, and it has achieved full commercialization for MRI and NMR applications. Superconducting technology has got on spotlight recent years for transportation, power network, and fusion energy, due to the significant advantages offered against its counterpart technologies, including lighter weight, compacter size, lower losses, higher efficiency, and higher power density. Therefore, many superconducting applications are moving towards higher technology readiness levels, with a fast pace. The accelerated research around superconducting applications for modern transportation is due to unique features of this technology towards decarbonisation via electrified systems. Meeting the Net Zero targets to decelerate global warming issue is the main driver of implementing the superconducting technology for aerospace, marine, and railway transport. However, many challenges still remain to be addressed for superconducting devices and applications, which will in turn pave the way for the commercialization of superconducting technology. In this article, a roadmap on electrification of transportation systems for aerospace, marine, and railway application is presented, covering challenges and solutions in design analysis, modelling, monitoring, and operation. A series of short articles are presented to outline the potential applications and solutions. These potential futuristic routes and their materials/technologies are considered/suggested for a 10-20 years time-frame.

Permanent magnet electrodynamic suspension (PMEDS) spares the competitive merits over others in structure simplicity and cost, but its inherent lateral instability remains a major obstacle for implementation. This work proposes the passive self-centering perforated guideway featuring periodic symmetric rectangular apertures that reshape eddy currents into an electromagnetic potential well, and it produces the lateral restoring force without auxiliary magnets or coils. Corresponding 3D theoretical model is derived and validated through the periodic lateral–longitudinal simulation model. In addition, the multi-objective optimization of the proposed guideway is carried out, and its dynamic electrodynamic characteristics are analyzed through theoretical calculation and simulation. Moreover, the lateral-vertical dynamic analysis is conducted to examine its self-centering guidance performance. Finally, a physical guideway is fabricated, and equivalent tests are performed. The results unveil that the proposed guidance mechanism can overcome the inherent lateral instability of the conventional complete guideway and achieve self-centering guidance. This work can share a simple and low-cost guidance solution for PMEDS system.

High-temperature superconducting (HTS) maglev technology shows significant potential for tourist rail transportation due to its self-stabilization, environmental benefits, and low noise. Existing researches on HTS maglev vehicles focuses more on high-speed design, while as sightseeing vehicles, they will face more complex routes, especially smaller curve radius, which puts higher demands on the curve passing performance. Therefore, additional analysis should be conducted on the working conditions during small-radius curve negotiation. As one of the main components of maglev vehicles, the rationality of the structural design of the levitation bogie is the key to the safety and stability of the vehicle, and it also directly affects the vehicle's curve passing performance. This paper first conducted a geometric analysis of the lateral displacement of the levitation bogie when passing through the curve, and designed a radial mechanism (RM). Then, a prototype of the HTS maglev bogie experiment considering the RM was constructed, and the vibration response of the levitation bogie under different conditions was tested using the HTS ring test line platform. Finally, a dynamic model of the HTS maglev sightseeing vehicle with the RM was established, and the curve passing performance and dynamic response were analyzed. The results confirm that under the action of RMs, the lateral displacement of HTS levitators is significantly reduced, which can effectively improve the curve passing performance of HTS maglev system, providing theoretical basis and reference suggestions for the engineering application of HTS maglev bogie in small curve radius passing scenarios.

A new type of transportation vehicle, the maglev car, is gaining attention in the automotive and maglev industries due to its potential to meet personalized urban mobility and future travel needs. To optimize the chassis layout of maglev cars, this paper proposes a compact powertrain integrating electrodynamic suspension with in-wheel motor technology, in which a permanent magnet electrodynamic in-wheel motor (PMEIM) enables integrated propulsion and levitation. First, the PMEIM external magnetic field distribution is characterized by analytical and finite element (FEM) approaches, revealing the magnetic field distortion of the contactless powertrain. Subsequently, the steady-state electromagnetic force is modeled and the operating states of the PMEIM powertrain are calculated and determined. Next, the PMEIM electromagnetic design is conducted, and its electromagnetic structure rationality is verified through magnetic circuit and parametric analysis. Finally, an equivalent prototype is constructed, and the non-contact electromagnetic forces of the PMEIM are measured in bench testing. Results indicate that the PMEIM powertrain performs propulsion and levitation functions, demonstrating 14.2 N propulsion force and 45.8 N levitation force under the rated condition, with a levitation-weight ratio of 2.52, which hold promise as a compact and flexible drivetrain solution for maglev cars.

The application of YBa2Cu3O7-x high-temperature superconducting (HTS) bulks in magnetic levitation trains with Nd-FeB magnet arrays guideway still faces the problem of attenuation of the levitation force. Therefore, the electromagnetic compensation subsystem has been proposed for this train to enhance its levitation force. However, the introduction of electromagnetic subsystems has affected the self-stabilized environment of the original system. To clarify the boundary conditions for this influence, four levitation modes of the hybrid levitation system have been proposed. Research has shown that under levitation conditions, there is only one equilibrium solution for the hybrid system, and an upper boundary condition exists. Meanwhile, singularities will attract each other and degenerate into single singularities with changes in electromagnetic force, and the stable region will be further squeezed and eventually disappear. The oscillation between the saddle point and the stable point exists in the critical state of the hybrid system. According to the central manifold theorem, hybrid systems will have saddle-node bifurcations, but they are limited by the current intensity. These boundary conditions, combined with existing experiments, can stimulate the application of electromagnetic devices in conjunction with HTS bulks.