• Journal of the Korean Society for Railway
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• v.18 no.1
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• pp.15-24
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• 2015

In magnetic levitation vehicles, the clearance between the magnet and track should be maintained within an allowable range through a feedback control loop. The flexibility of the guideway would introduce additional modes in the overall suspension system, resulting in dynamic interaction between the guideway vibration and the electromagnetic suspension control system. This dynamic interaction can be a serious problem, particularly at very low speeds or standstill, and may cause airgap instability. To optimize the overall system dynamics, an integrated dynamic model including mechanical and electrical parts and a flexible guideway as well as a control loop was developed. With the proposed model, airgap simulations at standstill were performed while varying the control gains, specifically with the aim of understanding the effects of gains of the PID controller on the airgap variation. The findings may be used to achieve a stable levitation controller design.

• Journal of the Korean Society for Railway
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• v.18 no.2
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• pp.87-93
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• 2015

The uneven reaction surface profile facing the lift magnets in attractive Maglev vehicles naturally brings about pitch motion of the bogie. In particular, in the placement configuration of the long stator of the linear synchronous motor (LSM) on the track for high-speed propulsion, surface irregularities and the offsets between the stator packs create measurable airgaps, i.e., the clearance between the magnet and the stator, with discontinuously extreme values, resulting in bogie pitch motion. This occurs because the airgap velocities and accelerations derived by the differentiations of the measured air-gaps are used to determine the voltages applied to the magnets. This paper incorporates bogie pitch motion into a control law for each magnet controller to reduce the variations in both the airgap and the pitch angle. The effectiveness of the proposed method is analyzed using a full-scale Maglev vehicle running over a test track.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.48.4-48
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• 2001

Major objective of this paper is to develop the sliding mode control method for a nonlinear electro magnetic levitation system governed by a set of a second-order motion equation and a first-order electromagnetic equation. Simulations for initial responses were carried out to confirm the validity of the present design method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.87-95
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• 2018

The high-precision magnetic levitation transport system is a transport device applying the principle of magnetic levitation. So it is preferable for manufactory process of semiconductor and display industries. In this system, the gap sensors are arranged discontinuously and turned on or off when the tray moves in the running direction. Therefore, precise gap data is important for precise control of the carrier. However, a slight error occurs in the process of installing the gap sensor. So, in this paper, we introduce the high-precision magnetic levitation transport system for OLED evaporation process. Also, we propose a strategy for stable flight control and an offset algorithm for tracking installation errors transport system. The performances of the proposed algorithm are validated through simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.4
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• pp.321-327
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• 2011

This paper proposes an equipment and an algorithm for modeling the magnetic force of electromagnets in magnetic levitation systems. We assume that the magnetic force model is represented in terms of a 2D lookup table. The 2D lookup table is constructed by applying noncausal filtering and interpolation to data measured by the proposed modeling equipment. The proposed modeling equipment is designed such that it can measure the magnetic force exerted on the levitation object while it changes the voltage applied to the electromagnet and position of the levitation object. The algorithm of making a 2D lookup table has two stages. The data measured by the proposed modeling equipment is smoothed by a noncausal filter and then the 2D lookup table is obtained by interpolating filtered data. The proposed modeling method has advantages of time-saving, model consistency, and chance of automation for mass production. We show the validity of proposed method through control experiments.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.3
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• pp.11-17
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• 2017

The aerial support air sculptures currently exhibited in indoor spaces are similar to simple ad balloons, using multiple rope strands. Users now want more advanced unfixed sculptures, and hope these will develop into buoyant sculptures that can maintain the attitudes that users want on their own. This study investigated an attitude control system for unfixed levitation sculptures that can levitate with no rope and continuously maintain a certain attitude at a height specified by the user. To facilitate levitation, the exterior part of the sculpture was made of lightweight fibers, and the interior part was filled with helium gas. The controller was composed of a microprocessor of the dsPIC30F line from microchip, gyro, acceleration, and earth magnetic field sensors, and a highly efficient brushless DC (BLDC) electric motor. The attitude and position control system requires scheduling considering the trajectories of the sculpture and the control system, because the roles of the overall components are more important than those of a single controller. Furthermore, the system was designed like a fusion system that is expanded and controlled as a total controller, because it is interconnected with various sensors. The attitude control system of buoyant sculptures was implemented in this study, such that it can actively cope with the position, direction, stopping, and time aspects. The system performance was then evaluated.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1557-1560
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• 1997

In this paper, we have built an experimental magnetic levitation system for a possible use of control education. We have give a mathermatical model of the nonlinear system and have shown the stability region of the linearized system when it is controlled by a PD controller. We also proposed a neural network control system which uses a neural network as a feedforward controller thgether with a conventional feedback PF controller. We have generated a desired output trajectory, which was designed for the benefit of the generalization of the neural network controller, and trained the desired output trajectory, which was desigend for the benefit of the generalization of the neural netowrk controller, and trained a neural network controller with the data of the actual input and the output of the system obtained by applying the desired output trajectroy. A good tracking performance was observed for both the desired trajectiories used and not used for the neural network training.

• Proceedings of the KIEE Conference
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• summer
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• pp.992-994
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• 2004

In this paper, hybrid electromagnets using NdFeB permenant magnet are designed by 3-dimensional finite element analysis. Four hybrid magnets levitate the carrier of which total weight including control circuits and battery is 14[kg]. The nominal air gap length of the hybrid magnet is 3[mm]. The control circuit consists of DSP, 4-quadrant chopper, and gap sensor as feedback sensors. As a result, some experimental results for the magnetic levitation control by PI feedback control theory are shown.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.384-387
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• 1990

This paper describes the design of the power conversion system for the 3-ton prototype magnetic levitation system. Electric power needed for the propulsion and levitation system of the vehicle is supplied by the wayside rectifier through the power rail and is picked up by the on board power collector, and is supplied to the propulsion VVVF inverter and levitation chopper. In this paper, design characteristic of the VVVF inverter, chopper and power source unit which provides control power to the levitation controller and levitation power to the chopper is described.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.623_624
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• 2009

This paper deals with the characteristic analysis of electro-magnet (EM)-permanent magnet (PM) hybrid levitation and propulsion device for magnetically levitated (maglev) vehicles. Several machine characteristics such as levitation force with/without control current and thrust are described. In order to verify the analysis results and feasibility of high-speed operation of the maglev vehicle, real-scale static test set is implemented and tested.