Study on Dynamic Characteristics of Superconducting Capsule Train

Yoon, Ranhee; You, Won-Hee; Lee, Jinho; Lee, Changyoung; Lee, Kwan-Sup

doi:10.5050/ksnve.2019.29.4.453

Cited by 2 publications

(8 citation statements)

References 6 publications

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“…As shown in Figure 6, the fluctuation in this levitation force is almost sinusoidal, and this component can also be expressed as an approximate equation. From Figure 9, the maximum, average, and minimum values of the levitation stiffness with respect to the vertical positions can be expressed as quadratic functions for Designs A, B, and C, as expressed in Equations ( 7)-( 15) [21,[25][26][27][28][29]. Here, the unit is N/m.…”

Section: Levitation Stiffness With Respect To the Vertical Positionmentioning

confidence: 99%

“…Coefficients of levitation stiffness (average and oscillation). On the other hand, one period of the oscillation component of the levitation stiffness is the time passing through one pitch of the levitation coil, and the levitation stiffness is a function of the position x in the traveling direction and the position z in the vertical direction and can be expressed as Equation ( 18) [21,25,26]. The pitch (τ l ) of the levitation coil for each design is listed in Table 5.…”

Section: Levitation Stiffness With Respect To the Vertical Positionmentioning

confidence: 99%

“…As in the case of the levitation stiffness, the fluctuation in this guidance force is almost sinusoidal, and this component can also be expressed as an approximate equation. From Figure 13, the maximum, average, and minimum values of the guidance stiffness with respect to the lateral position can be expressed as a quadratic function for Designs A, B, and C, as expressed in Equations ( 22)-( 30 From Figure 13, the maximum, average, and minimum values of the guidance stiffness with respect to the lateral position can be expressed as a quadratic function for Designs A, B, and C, as expressed in Equations ( 22)-( 30) [21,[25][26][27][28][29]. Here, the unit is N/m.…”

Section: Guidance Stiffness With Respect To the Lateral Positionmentioning

confidence: 99%

“…In addition, the magnitude of the guidance force is the highest in Design A and the lowest in Design C. The change rate of the guidance force is the lowest in Design B. On the other hand, the levitation and guidance forces depend on the speed of the traveling body, vertical position, and lateral position, and there is a fluctuation component with respect to the levitation coil pitch [22][23][24][25][26]. In addition, in the EDS system, the levitation and guidance forces between the traveling body and the guideway (or levitation coil) can be expressed in the form of an equivalent stiffness, similar to that in the case of the primary suspension of a railway vehicle [21,25,26].…”

mentioning

confidence: 99%

“…On the other hand, the levitation and guidance forces depend on the speed of the traveling body, vertical position, and lateral position, and there is a fluctuation component with respect to the levitation coil pitch [22][23][24][25][26]. In addition, in the EDS system, the levitation and guidance forces between the traveling body and the guideway (or levitation coil) can be expressed in the form of an equivalent stiffness, similar to that in the case of the primary suspension of a railway vehicle [21,25,26]. In other words, the equivalent stiffness due to the levitation force (hereinafter referred to as "levitation stiffness") can be considered the primary vertical spring of the railway vehicle, and the equivalent stiffness (hereinafter referred to as "guidance stiffness") because of the guidance force can be considered Both the levitation and guidance forces include a nonzero constant component and a sinusoidal component.…”

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confidence: 99%

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Capsule Vehicle Dynamics Based on Levitation Coil Design Using Equivalent Model of a Sidewall Electrodynamic Suspension System

et al. 2021

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A levitation system based on sidewall electrodynamic suspension (EDS) is considered for a capsule vehicle, which is a next-generation high-speed transportation system currently being studied. This levitation system does not require controlling of the gap between the guideway and the vehicle on which the superconducting electromagnet is mounted. However, when the vehicle is operated in a levitated state, the ride comfort is worse than that of the levitation system based on electromagnetic suspension (EMS), making it necessary to develop methods that can ensure good riding comfort. In addition, because the EDS system is complex and nonlinear with a combination of electromagnetics and mechanical dynamics, it is complicated to analyze the dynamic characteristics of the capsule vehicle, and the corresponding numerical analysis is time-consuming. Therefore, to easily understand the running dynamics of a capsule vehicle in the sidewall EMS system, the magnetic suspension characteristics corresponding to the primary suspension are simply modeled by considering the levitation stiffness in the vertical direction and the guidance stiffness in the lateral direction, similar to that in the case of the mechanical suspension. In this study, mathematical models of the levitation and guidance stiffnesses with respect to the speed and position of a vehicle body running at high speeds in a levitated state in the sidewall EDS system were derived for three design proposals of the levitation coil. The dynamic behavior of the vehicle based on the three design proposals was investigated by simulating a capsule vehicle model with 15 degrees of freedom.

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Section: Levitation Stiffness With Respect To the Vertical Positionmentioning

confidence: 99%

Section: Levitation Stiffness With Respect To the Vertical Positionmentioning

confidence: 99%

Section: Guidance Stiffness With Respect To the Lateral Positionmentioning

confidence: 99%

mentioning

confidence: 99%

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confidence: 99%

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Capsule Vehicle Dynamics Based on Levitation Coil Design Using Equivalent Model of a Sidewall Electrodynamic Suspension System

et al. 2021

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Bi-exponential model and inverse model of magnetorheological damper for the semi-active suspension of a capsule vehicle

Yoon

Negash

You

et al. 2022

Measurement and Control

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The capsule vehicle is a new transportation system that travels in a sub-vacuum tunnel at a speed of about 1000 km/h, and adopts the electrodynamic suspension type levitation system. Accordingly, although it differs according to the driving speed, the vibration of capsule vehicle is expected to be greater than that of the wheel/rail type high-speed rail vehicles. Therefore, a method of applying a semi-active control technique using an MR damper as a secondary suspension of a capsule vehicle to improve passenger comfort is being studied. When performing semi-active control using an MR damper, the most important thing is to determine the current for the MR damper. However, it is difficult to determine the appropriate current for the MR damper because of the hysteretic characteristics of the MR damper. In this study, a practical model named the Bi-exponential model is presented for the application of semi-active control using MR dampers on a capsule vehicle. This Bi-exponential model well reflects the hysteretic characteristics of the MR damper, which makes it easy to obtain the inverse model for determining the current supplied to the MR damper. The semi-active control performance of the Bi-exponential model was evaluated by simulation and a HILS experiment, taking into account the vertical motion of a 1/4-car capsule vehicle. Also, the Bi-exponential model has been validated against the performance of the most commonly used Bouc-Wen model. As a result, the Bi-exponential model showed better hysteretic characteristics of MR dampers compared to the Bouc-Wen model. Furthermore, despite the simpler model compared to the Bouc-Wen model, the semi-active control performance of the Bi-exponential model was found to be better.

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Study on Dynamic Characteristics of Superconducting Capsule Train

Cited by 2 publications

References 6 publications

Capsule Vehicle Dynamics Based on Levitation Coil Design Using Equivalent Model of a Sidewall Electrodynamic Suspension System

Capsule Vehicle Dynamics Based on Levitation Coil Design Using Equivalent Model of a Sidewall Electrodynamic Suspension System

Bi-exponential model and inverse model of magnetorheological damper for the semi-active suspension of a capsule vehicle

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