• Title, Summary, Keyword: Magnetic levitation

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AN EFFICIENT SENEOR ARRAY FOR A LATFE-GAP MAGNETIC LEVITATION SYSTEM

  • Na, Seung-You;Shin, Dae-Jung
    • 제어로봇시스템학회:학술대회논문집
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    • pp.154-157
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    • 1995
  • A magnetic levitation control system is nonlinear and very unstable. Thus there should be a stabilizing compensation network and a feedback path. Due to the levitation control a noncontact photoresistor sensor is generally used. One photocell provides a certain amount of variation in length by the ball shadow casted on the cell surface. Furthermore at the boundary of the cell, the linearity of sensitivity deteriorates severely. To overcome the constraints of the length and linearity, an efficient sensor array is deviced and applied in the feedback path of a large-gap magnetic levitation control system. A number of CdS photocells and a summing circuit of the sensor output signals are used for a sensor array. The levitation length of a ball and the transient performances are main objectives of the large-gap suspension system using the sensor array.

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Zero Power Levitation Control of Hybrid Electro-Magnetic Levitation System by Load Observer (부하 상태관측기에 의한 하이브리드 부상 시스템의 제로 파워 부상 제어)

  • Kim, Youn-Hyun;Lee, Ju
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.6
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    • pp.282-289
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    • 2001
  • This paper introduces the scheme that improve the control performance of electromagnetic levitation system with zero power controller. Magnetic levitation is used widely, but the electromagnetic force has nonlinear characteristics because it is proportioned to a square of the magnetic flux density and it is in inverse proportion to a square of the airgap. So, it is complicate and difficult to control the electromagnetic force. Besides, it is more difficult to control if the equivalent gap is unknown in case of zero power control. Therefore, this paper proposed the hybrid electro-magnetic levitation control method in which the variable load is estimated by using a load observer and its system controlled at a new zero power equilibrium airgap position. Also it is confirmed that the proposed control method improve the control performance through simulation and experiment.

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Stability Analyses of Magnetic Levitation Tables Using Repulsions of Permanent Magnets (영구자석에 의한 반발형 자기부상 테이블의 안정성 해석)

  • Choe, Gi-Bong;Jo, Yeong-Geun;Tadahiko Shinshi;Akira Shimokohbe
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.7
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    • pp.36-42
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    • 2002
  • This paper presents two actuators for levitation using repulsions of permanent magnet and two magnetic levitation tables using the actuators. Here, one actuator for levitation consists of one fixed magnet and one moving magnet, and the other actuator consists of two fixed magnets and one moving magnet. The moving part of the magnetic levitation table contains the moving magnets. repulsive forces caused by the permanent magnets are linearized, and then the equation of motion of the moving part of the table is derived. Using the equation of motion, stability conditions of the moving part are deduced. The stability conditions are analyzed for positional relations of the moving magnets and the minimum number of active control required for stable system. As a result, in the each case of magnetic levitation tables, the requirements for stabilization are expressed by the positional relations and the number of the active controls.

Concrete Structure System for the German Magnetic Letic Levitation Train (독일자기부상열차의 콘크리트 구조물 시스템)

  • 강보순
    • Proceedings of the KSR Conference
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    • pp.393-400
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    • 2001
  • State of the art and current issues related with the RC and PSC structure system for the German magnetic levitation train were investigated. The German magnetic levitation train adopted a new kind of a structure to enable high-speed transportation, which allows the use of the space over a ground. The loading from Transrapid is light-weight compared with a regular train due to load distribution to a supporting structure. Therefore, Transrapid is considered an economical and efficient transportation system, and is also an environmentaly-sustainable structure, In this paper, the structural design and construction technology specific to a magnetic levitation train were discussed, and structural considerations related with an actual operation of the train were pointed out. In addition, the future research area of a magnetic levitation train was proposed.

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A Study on the Sensorless Realization of Magnetic Levitation System by Two-Degree-of-freedom Control Method (2자유도 제어기법에 의한 자기 부상계의 센서리스 실현에 관한 연구)

  • 양주호
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.6
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    • pp.888-893
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    • 1998
  • In this paper, we present a magnetic levitation system which has not a gap sensor with sensor-less realization and stabilizing controller design. For measuring gap between magnet and levitated object we propose a gap sensorless method and adop two-degree-of-freedom controller for robust-ness and performence of the magnetic levitation system. From time responeses we confirm that the proposed sensorless method which can be applied to magnetic levitation system. Also the designed stabilizing controller has good disturbance rejection and reference tracking performance.

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Position Control of Magnetic Levitation Transfer System by Pitch Angle

  • Liu Ming-Zhao;Tsuji Teruo;Hanamoto Tsuyoshi
    • Journal of Power Electronics
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    • v.6 no.3
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    • pp.264-270
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    • 2006
  • Magnetic levitation transfer systems are useful for transfer tools in clean rooms and positioning control systems with high precision because of frictionless characteristics. In this paper, the new method is proposed which is a sensorless position. At first, the magnetic levitation is performed by state feedback control with a disturbance observer for each of six axes of the movement of a levitated vehicle. The position of the vehicle is then estimated as the disturbance term of a disturbance observer for a pitch angle which is one of the control axes for the magnetic levitation. In addition, the positioning force is generated by the pitch angle control which gives a tilt to the levitated vehicle so that it generates the horizontal component of force.

A Study on the Control and Estimation of Gap Sensor Offset in High-Precision Magnetic Levitation Transport System (초정밀 자기부상 물류 이송장치의 제어 및 공극 센서 오프셋 추정 연구)

  • Kim, Min;Kim, Chang-Hyun;Ha, Chang-Wan;Won, Mooncheol
    • 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.

Sliding Mode Control based on Disturbance Observer for Magnetic Levitation Positioning Stage

  • Zhang, Shansi;Ma, Shuyuan;Wang, Weiming
    • Journal of Electrical Engineering and Technology
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    • v.13 no.5
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    • pp.2116-2124
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    • 2018
  • Magnetic levitation system with the advantages of non-contact, no friction and no wear can satisfy the requirement of high precision and high speed positioning. In this paper, magnetic levitation positioning stage which mainly consists of planar coil and HALBACH permanent magnet array and its control and driving system are designed. Magnetic levitation system is a highly nonlinear and strongly coupled complex system and its control performance can be influenced by the uncertainty and external disturbance. So exact feedback linearization method is used to realize exact linearization and decoupling, and a strategy of sliding mode control based on disturbance observer is proposed to compensate the uncertainty and external disturbance. Detailed proofs of observer's convergence property and system stability are derived. Both the simulation and experiment results verify the effectiveness of sliding mode control algorithm based on disturbance observer.

Performance Evaluation of Sliding Mode Control using the Exponential Reaching Law for a Magnetic Levitation System (자기부상 시스템을 위한 가속율도달법칙기반의 슬라이딩 모드 제어 성능 평가)

  • Moon, Seok Hwan;Lee, Ki Chang;Kim, Ji Won;Park, Byoung Gun;Lee, Min Cheol
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.4
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    • pp.395-401
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    • 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.

Dynamic Modeling of an Fine Positioner Using Magnetic Levitation (자기 부상 방식 미세 운동 기구의 동적 모델링)

  • Jeong, Gwang-Seok;Baek, Yun-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.5
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    • pp.1166-1174
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    • 2000
  • In this paper, we introduce a positioner based on magnetic levitation to eliminate the friction which is the most severe effect to limit high resolution on the micro level. Differently from existing electromagnetic device, the proposed positioner consists of air core solenoid and permanent magnet. Although the combination produces small magnetic force, it is suitable for realizing micro motion repeatedly without the accumulation of error because there is no hysteresis caused by ferromagnetic materials, no eddy current loss, no flux saturation. First, the approximate modeling of stiffness and damping effects between the magnetic elements is made and verified experimentally. Then, we have formulated the dynamic equation of one d.o.f magnetic levitation positioner using linear perturbation method and discussed the necessity of optimization for the chief design parameters to maximize the stability performance.