• 소음진동
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• 제6권3호
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• pp.357-362
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• 1996

The magnetic levitation system has great advantages, such as little friction, no lubrication, no noise and so on. But the magnetic levitation system need a stabilizing controller because it is a unstable, system in natural and it need a sensor for displacement measurement to control the system. In this paper, we proposed a sensorless method to measure the gap between the magnetic pole and the levitated object with application the inductance characteristic which vary according to gap. We made a driving circuit which supply simultaneously the control input PWM(Pulse Width Modulation) signal and the carrier PWM signal to estimate the gap. Because the inductance is a function of gap, and the current of the carrier signal is a function of the inductance, we could estimate the gap from the measurement of the current of the carrier signal. Finally, we investigated the validity of the proposed method through the experimental results.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2609-2614
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• 2011

A proportional integral derivative (PID) controller is designed and applied to a magnetic levitation conveyor system to control the levitation gap length of the electromagnet constantly. The PID gain parameters are optimized by response surface methods (RSM). The controller is verified with the state-space model of electromagnetic suspension by MATLAB/SIMULINK program. And, the controller and the state-space model are also verified experimentally. Simulation and experimental results shows the effectiveness of the PID gain tuning by RSM as compared with the classical PID tuning.

• 조명전기설비학회논문지
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• 제16권3호
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• pp.67-73
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• 2002

본 논문에서는 자기부상시스템의 상태추정을 위한 슬라이딩모드 관측기와 동적 안정화를 위한 슬라이딩모드 제어기를 제안한다. 제안된 슬라이딩모드 관측기는 관측오차를 감소시키기 위해서 Lyapunov 안정도이론에 의하여 구성되고, 추정된 상태에 대해서 등가 제어입력과 비선형 제어입력의 일차결합으로 슬라이딩모드 제어기가 설계된다. 제안된 설계방법의 유용성은 모의실험결과로부터 검증한다.

• 한국정밀공학회지
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• 제14권9호
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• pp.68-79
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• 1997

A six DOF fine manipulator based on magnetic levitation is developed. Since most of magnetic levitation system are inherently unstable, a proposed magnetically levitated fine manipulator is implemented by use of an antagonistic structure to increase stability. From mathematical modeling and experiment, the equations of motion are derived. In addition, a six DOF sensing system is implemented by use of three 2-axis PSD sensors. A model reference-$H_{\infty}$ controller is applied to the system for the position control, In application of the fine manipulator, a wafer probing system is proposed to identify nonfunctional circuts. The probing system requires compliance to avoid destruction of DUT(device under test). A feedfor- ward-PD controllers are presented by the terms of the position accuracy, the settling time and the force accuracy.y.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권12호
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• pp.689-697
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• 2005

In this paper, an application of a decentralized $H_{\infty}$ controller(DHC) to multiple controlled-permanent magnet(CMAG) magnetic levitation(Maglev) systems is presented. The designed DHC using two Riccati equations iteratively has simpler structure and needs less computational loads than conventional centralized $H_{\infty}$ controller. A target plant is a hybrid-type CMAG system with permanent magnet and coil, and its mathematical model is firstly derived to design the DHC. To implement the designed algorithm, a real Maglev vehicle system including digital controller, chopper, sensor, etc., is manufactured. To compare the performances of the DHC method with an observer-based state feedback control(OSFC), the input tracking and disturbance rejection characteristics are experimentally tested. As performance indices(PI), integral of squared error(ISE), integral of absolute error(IAE), integral of time multiplied by absolute error(ITAE) and integral of time multiplied by squared error(ITSE) are used. From the experimental results, it can be seen that the input tracking and disturbance rejection performances of the DHC are better than those of the conventional controller.

• 동력기계공학회지
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• 제4권3호
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• pp.62-71
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• 2000

A mathematical modeling for a magnetic levitation system is proposed using the Taylor series expansion of differential function for obtaining linearity. It is confirmed that this kind of linear approximation method can be used to the modeling of a magnetic levitation system. The two-degree-of-freedom optimal servo system for a constant reference signal is proposed using the LQ optimization technique. An additional state feedback is introduced at the output of the integrator to cancel the integral action for reference signal if there is no modeling error of the plant and no disturbance input to the plant. When the modeling error or the disturbance input exists, the integral effect appears. The system has a free parameter which can b used to tune the effect of the integral compensation.

• 한국산학기술학회논문지
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• 제7권5호
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• pp.830-836
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• 2006

본 논문에서는 기존의 PID 제어기와 퍼지 제어기의 특성을 공통으로 갖는 새로운 형태의 신경회로망 기반 자동 동조 뉴로-퍼지 PID제어기를 제안하였다. 제안된 제어기는 퍼지의 선형성을 이용하여 퍼지 PID 제어기의 퍼지 연산부를 간략화 시키고 일반 PID 제어기와 유사한 입출력 특성을 갖도록 하였으며 비선형 성분 보상을 위하여 제어기 출력에 가장 큰 영향을 미치는 출력측 스케일 계수를 단일 신경 회로망 구조로 변경하고 PID 제어기 구조를 유지하게 하였다. 또한 단일 신경 회로망 구조를 이용함으로써 신경회로망의 초기 연결강도와 계산량에 대한 문제점을 해결하고 오차의 부호 정보에 따라 학습계수를 변화시키는 가변 학습계수 역전파 알고리즘을 사용하여 오버 슈트가 작으면서도 빠른 수렴 속도를 갖도록 하였다. 제안된 제어기를 비선형성이 강한 시스템으로 알려진 자기 부양(magnetic levitation) 시스템에 실제 적용하여 본 논문에서 제안한 제어기의 우수한 성능을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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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.

• 한국철도학회논문집
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• 제18권1호
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• pp.15-24
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• 2015

상전도흡인식 자기부상열차는 전자석의 전류를 조정하여 차량과 선로 사이의 간극(공극)을 일정하게 유지한다. 이러한 능동현가장치를 사용하는 자기부상열차에 있어서는 다양한 외란에도 불구하고 부상제어기를 이용한 부상공극을 허용하는 범위 내로 유지하는 것이 핵심기술 중의 하나이다. 특히 차량과 유연한 가이드웨이 사이의 동적상호작용에 의해 발생되는 진동은 저속 및 정지상태에서 부상안정성을 방해하는 중요한 요인으로 작용한다. 본 논문에서는 가이드웨이의 유연성에도 강인한 부상제어기를 개발하기 위하여 차량과 유연 가이드웨이 사이의 연성 동역학 모델을 개발하고, 전자석 및 부상제어기도 포함시키는 통합모델링을 제안하였다. 개발된 통합동역학 모델을 이용하여 가이드웨이의 유연성을 고려한 부상공극 시뮬레이션을 수행하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.733-734
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• 2006

In this parer, characteristics of the flexible rail in levitation control system are analysed. The magnetic levitation system is an electromagnet type and is full-scaled vehicles. The system consists of electromagnet, chopper, flexible rail, secondary suspension system and levitation controller. The mathematical modelling for the whole system is carried out. Especially, the flexible rail is modelled using second-order mass-spring-damper system. Using the derived model, the dynamic characteristics for the system are presented with different vehicle speed.