• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_2
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• pp.1127-1134
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• 2023

In this paper, we proposes a study on air gap control for magnetic levitation of transverse flux permanent magnet electromagnets. In general, mechanical systems have a high failure rate of bearings. Bearings in particular are problematic because they have high surface wear rate and degradations. To solve this problem, replacing the bearing with a magnetic levitation electromagnet system can provide lightweight and efficiency improvements. However, precise air gap control is essential to control the magnetic levitation electromagnet system. Therefore, in this paper, we identify the instable cause of gap control through a mathematical modeling and verify through experiment a control algorithm that can use compensation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.7
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• pp.444-451
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• 2004

Conventional magnetic levitation systems could show unsatisfactory performance under air-gap disturbance due to rail irregularities. In this paper, we propose a feedback control system with discrete Kalman filter for air-gap disturbance attenuation. It is shown that excellent system performance can be obtained with the use of discrete Kalman filter, and that results from experiments agree well with those of simulations.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.6
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• pp.913-920
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• 2013

This paper presents an applicable basic design that can configure non-contact levitation table for conveying a large sheet of glass. The suggested air levitation table consists of a series of air chambers with porous pads and fans as the conveyor system. The air supply chambers are arrayed to supply an adequately strong upward airflow for supporting the glass. Levitation is controlled by the size and discharge velocity, of the chamber arrays, as well as the glass supporting height. After pre-evaluation of the glass rigidity and the filer functional performance, a one-way fluid structure interface (FSI) analysis is performed for predicting pressure and deflection working of the 8G glass in the transverse and longitudinal directions, respectively. After comparing calculated levels of flatness of the glass, it determines the chamber array for the linear non-contact conveying motion.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1191_1192
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• 2009

The objective of levitation control design is to stabilize a levitation system, or obtain certain transient response, bandwidth, and steady state error. An air gap signal from the each corner is important parameter to design levitation controller. A levitation controller using gap signals with measurement delay time can not make a expected performance. In this paper, a new air gap estimator to improve the performance of levitation controller is proposed. The estimated gap signal which has little measurement delay time is used as a feedback value in the levitation controller.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.11
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• pp.541-546
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• 2006

In a levitation magnet system with large air gap, numerical method is needed because analytic method cannot consider the leakage flux properly. This paper conducted an optimal design of a levitation magnet system with large air gap which was used for an OLED system, where evolution strategy was adopted for optimal design algorithm. Levitation forces near the initial design were calculated first by using finite element method to reduce the computation time. During the optimization process, levitation forces of arbitrary dimension were obtained using the interpolation of the levitation forces which were calculated previously Weight of the maget system was chosen as the object function and it was used minimized.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.9
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• pp.515-521
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• 2002

This paper presents the scheme that improves control responsibility and stability of the controlled-PM electromagnet levitation system with zero Power controller. A magnetically levitation system is used widely because friction can almost be disappeared. But it is difficult to control due to restraint of controllable area and nonlinear characteristics of electromagnetic force, which is proportioned to a square of the magnetic flux density and is in inverse proportion to a square of the air-gap. So, the application of observer theory in which the levitation system is considered to be a linear dynamic model has resulted in omitting the time dependence on mover's speed. Consequently, the performance of the observer is quite poor during transients. Therefore, this paper proposed the controlled-PM electro-magnetic levitation control method in which the variable load is estimated by using the reduced order extended luenverger observer and its system is controlled at a new zero power equilibrium air-gap position. It is also verified that the proposed control method improve the control performance through simulation and experiment.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.165-171
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• 1998

An axial electromagnetic levitation system using attractive force is a highly nonlinear system due to the nonlinearity of materials, variable air gap and flux density. To control the levitating system with large air gap, a conventional PID control based on the linear model is not satisfactory to obtain the desired performance and the position tracking control of the sinusoidal motion by simulation results. Thus, sliding mode control(SMC) based on the input-output linearization is suggested and evaluated by simulation and experimental approaches. Usefulness of the SMC to this system is conformed experimentally. If the expected variation of added mass can be included in the gain conditions and the model, the position control performance of the electromagnetic levitation system with large air gap will be improved with robustness.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.9
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• pp.820-827
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• 2004

The propulsion force acting on a wafer in an air levitation system was measured accurately and then, the corresponding force coefficient was determined. The theoretical propulsion force on the wafer bottom surface were obtained by CFD simulations and from these results the propulsion force coefficient was deduced. The transportation velocity of a wafer was estimated by using both experimental and numerical force coefficients, for various air velocity of nozzle injection. When the numerical results are compared to the experimental data, the numerical results agree well Quantitatively.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1643-1651
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• 2002

Magnetic levitation systems are required to have a large operating range in many applications. As one method to solve this problem, Time Delay Control (TDC) is applied to a single-axis magnetic levitation system in this paper A reduced-order observer is utilized to estimate states excluding measurable states in the control law. The system consists of a square air-core solenoid and a circular permanent magnet attached on a plastic ball. Theoretical magnetic forces of the system are obtained on the basis of the location of the magnet around the solenoid. The magnetic levitation force is obtained by the experiment, and then compared with the theoretical one. As the results of the control experiments, the nonlinear controller (TDC : 1-2 ㎜) has a larger operating range than the linear controller (PD control : 1-1.4 ㎜), and is superior to linear. control in the robustness to the modeling uncertainty and the performance of the disturbance rejection.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.824-829
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• 2011

EMS-type Maglev vehicle maintains constant levitation air-gap between electromagnet and guideway by using gap sensor. The other words, when Maglev vehicles levitating over the guideway, mass of the vehicle effects through 1st (electromagnetic air-gap control) and 2nd (air-spring) suspension to grider. Resonace between electromagnetic suspension and grider could be occurred, which causes instability and poor ridecomfort. This paper is to test the dymanic interaction between levitation air-gap and switching system grider that has less mass and high natural frequencies than other type of general girders.