• Progress in Superconductivity and Cryogenics
• /
• v.17 no.1
• /
• pp.14-16
• /
• 2015

Due to the considerable development of the technology of second generation high-temperature superconductors and a significant improvement in their mechanical and transport properties in the last few years it is possible to use HTS tapes in the magnetic levitation systems. The advantages of tapes on a metal substrate as compared with bulk YBCO material primarily in the strength, and the possibility of optimizing the convenience of manufacturing elements of levitation systems. In the present report presents the results of the magnetic levitation force measurements between the stack of HTS tapes containing $n=2{\div}200$ of tapes $12mm{\times}12mm$ and NdFeB permanent magnet in the FC and ZFC regimes. It was found a non- linear dependence of the levitation force from the height of the array of stack in both modes: linear growth at small thickness gives way to flattening and constant at large number of tapes in the stack. Established that the levitation force of stacks comparable to that of bulk samples. The numerical calculations using finite element method showed that without the screening of the applied field the levitation force of the bulk superconductor and the layered superconductor stack with a critical current of tapes increased by the filling factor is exactly the same, and taking into account the screening force slightly different.

• International Journal of Railway
• /
• v.8 no.1
• /
• pp.21-29
• /
• 2015

This study focuses on the performance enhancement of the levitation and guidance control system in urban and medium-to high-speed magnetic levitation trains. A levitation control system, which is currently being tested in Yeongjongdo, is a single controller that is neither designed nor produced on the basis of redundancy. Hence, vehicular stability and reliability should be improved for the situation in which levitation failure occurs because of a breakdown in a controller during vehicle operation. In addition, the control system should be developed to control electromagnetic levitation considering changes in normal force according to changes in the driving force of the propulsion system.

• Proceedings of the KSR Conference
• /
• 1999.11a
• /
• pp.218-225
• /
• 1999

Dynamic analysis of the magnetic levitation vehicle UTM01 is studied using the multibody dynamic analysis program DADS. The magnetic levitation force is defined and incorporated into DADS through the user-defined subroutines of DADS. The vehicle with bogies is modeled in 3 dimension. The developed vehicle model with magnetic nodules is analyzed for two rail profiles. The results show that the presented method is applicable to magnetic levitation vehicles.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10b
• /
• pp.355-359
• /
• 1992

This paper presents a procedure to design a real time control system for a magnetic levitation system based on the state space approach by adopting a control method compensating attractive force according to load variation of maglev vehicle. Also the paper has realized a robust control algorithm for the change of self-inductance parameters and the disturbance such as the change of mass of Maglev vehicles. The theoretical results are applied to the gap control problems of an attractive-type-magnetic levitation system and the effectiveness is proved by the implementation of digital control using 16 bits microcomputer.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.974-978
• /
• 2007

In this paper, the requirements of passive levitation for nonmagnetic body in magnetic fluid are investigated. The passive levitation system includes the electromagnetic system composed of two hollow solenoids, the magnetic fluid and the nonmagnetic body made of aluminum. The hollow solenoids generate nonuniform magnetic fields, leading to the gradient of the magnetic field in magnetic fluid. Hence, the resultant magnetic body force in magnetic fluid is used to levitate the nonmagnetic body in the opposite direction of the gravitation. The levitation conditions according to applied current and the mass of the nonmagnetic body are obtained analytically.

• Progress in Superconductivity and Cryogenics
• /
• v.11 no.2
• /
• pp.15-19
• /
• 2009

Bulk $YBa_2Cu_3O_{7-{\delta}}$ (YBCO) superconductor was manufactured with the top-seeded melt grown method. The 9, 16, and 25 holes, as small as 0.7mm in diameter, parallel to the c-axis were mechanically drilled. Magnetic flux mapping and levitation force were measured and compared to estimate the influence of multiple holes on the magnetic properties of YBCO superconductor at 77K. According to the measurements, the maximum magnetic flux density obtained from the plain sample was 2.48kG, while the maximum magnetic flux density of the sample with 25 holes was low as around 2.29kG. The levitation force measured on the sample with 9 holes increased from 91N to 105N. The levitation force measured on the samples with 9 holes is relatively higher than the plain sample without any holes. In this case, increase of the levitation force in the perforated samples could be explained by enhancement of the cooling efficiency more effectively. We investigated that the magnetic properties of YBCO superconductor were strongly influenced by the artificial holes.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.4
• /
• pp.395-401
• /
• 2014

Magnetic levitation systems using the attraction force of electromagnets have many constraints according to the variation of air gap and the nonlinearity of electromagnetic force and inductances. As a result of these constraints, the nonlinear control of a magnetic levitation system has been improved by the latest advanced processors and accurate measurement system which can overcome problems such as many constraints and nonlinearity. This paper concentrates on the modeling of a nonlinear magnetic levitation system and an application of an exponential reaching law based sliding mode controller using the exponential reaching law which is one of the most robust controllers against external unexpected disturbances or parameter fluctuations. Controllability of a magnetic levitation system using the sliding mode control algorithm and robustness against parameter fluctuations have been verified through the experimental results.

• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.7
• /
• pp.557-561
• /
• 2016

Recently, in the manufacturing process of flat panel displays, mass production methods of inline system has been emerged. In particular the next generation OLED display manufacturing process, horizontal inline evaporation process has been tried. It is important for the success of OLED inline evaporation process to develop a magnetic levitation transport system capable of transferring a carrier equipped with a mother glass with high accuracy without any physical contact along the rail under vacuum condition. In the case of existing wheel-based transfer system, it is not suitable for OLED evaporation process requiring high cleanliness. On the other hand, the magnetic levitation transport system has an advantage that it does not generate any dust and it is possible to achieve high-precision control because there are not non-linear factors such as friction force. In this paper, we introduce the high-precision magnetic levitation transport system, which is currently under development, for OLED evaporation process.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.12
• /
• pp.1828-1835
• /
• 2012

In this paper, a conceptual design and a detailed design of novel cylindrical magnetic levitation stage is introduced. This is came from planar-typed magnetic levitation stage. The proposed stage is composed of cylinder-typed permanent magnet array and semi-cylinder-typed 3 phase winding module. When a proper current is induced at winding module, a magnetic levitation force between the permanent magnet array and winding module is generated. The proposed stage can precisely move the cylinder to rotations and translations as well as levitations with the magnetic levitation force. This advantage is useful to make a nano patterning on the surface of cylindrical specimen by using electron beam lithography under vacuum. Two methods are used to calculate required magnetic levitation forces. The one is 2D FEM analysis, the other is mathematical modeling. This paper shown that results of two methods are similar. An assistant plate is introduced to reduce required currents of winding module for levitations in vacuum. The mathematical model of cylindrical magnetic levitation stage is used for dynamic simulation of magnetic levitations. A lead-lag compensator is used for control of the model. Simulation results shown that the detail designed model of the cylindrical magnetic levitation stage with the assistant plate can be controlled very well.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.11
• /
• pp.75-80
• /
• 2000

Recently, there are a great many research for magnetic levitation system. In case electromagnet is operated as the actuator of control system, first of all, we must analysis about an electromagnet. Important parameters of this system are inductance(L) and resistance(R) which are induced from the coil of electromagnet. And attractive force equation is also important. If the load of this system is large, phase delay is caused by self-inductance effect. Because this delay effect cause stability of whole magnetic evitation system to grow worse, a measures to diminish time constant must have been taken. And the linearized attractive force equation which is used at small range of the operating point is compensated to use at larger range, thus the experiment of magnetic levitation system will get a better result.