• 한국정밀공학회지
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• 제19권12호
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• pp.109-119
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• 2002

In this paper, mechanism design of optical pickup actuator for fast access is proposed. This actuator is composed of moving magnet type actuator and moving coil type actuator for tracking and fine motion, respectively. Moving magnet type tracking actuator is configurated by two permanent magnets and four air-core solenoids. Additional damper by induced current in tracking actuator can reduce the transient vibration between the coarse seeking servo and fine seeking servo. Variable stiffness can be acquired by applying current to air-core solenoid simply. This actuator can achieve fast access by these additional damper and stiffness. Performance of this actuator is predicted through the FEM, simulation and simple experiment. Settling time for transient vibration is reduced to 14.7% according to simulation result.

• 한국소음진동공학회논문집
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• 제14권12호
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• pp.1255-1260
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• 2004

A moving-magnet type pickup actuator has an assembly error. That is, the actuating Part of an actuator is shifted from initial position after we assemble it into yoke. This Is the result of an effect of magnetic force between magnet and yoke. We performed magnetic-analysis using FEA. As a result of simulation, we improved the assembling efficiency for moving-magnet type actuator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.356-361
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• 2004

가동자석형 픽업 구동기를 조립하는 경우 조립 전후에 오차가 발생하게 된다. 즉, 렌즈홀더 와 스프링홀더 A'SSY 를 요크에 조립하기 전자 후에 렌즈홀더가 shift 된 양을 살펴보면 상당한 편차가 있음을 볼 수 있다. 이것은 자석 중심과 요크 중심이 어긋날 경우 자석과 요크 사이에 발생하는 자기력의 영향으로 발생하는 것으로, 자기해석을 수행한 결과 자석과 요크의 크기에 따라 자기력의 영향이 달라짐을 확인할 수 있었고, 개발모델에 적용하여 조립성능이 향상됨을 확인할 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1033-1036
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• 2007

The optical disc drive has used a high NA objective lens and a shorter wavelength laser diode for high recording density. But high NA and shorter wavelength cause several margins to become short. Focusing and tracking servo has to be more accurate and active tilt compensation mechanism is also needed for coma aberration compensation. In this paper, we proposed 3-axis moving magnet type actuator. For 3-DOF motion, moving coil actuator has to equip 6 wires for supplying 3 independent signals. However, moving magnet type actuator doesn't need to change the configuration of wires because coils are in stator. So, we added tilting mechanism to 2-axis moving magnet actuator which is designed in previous research. Addition of the tilting mechanism cuts down the focusing sensitivity. So, maximization the tilting sensitivity and securing the focusing sensitivity are objectivities of this research. DOE (design of experiments) procedures of electromagnetic circuit are performed for parameter study and the optimization is also performed to maximize the tilt sensitivity. And then the final design is suggested and its performance is verified by FE simulation.

• 정보저장시스템학회논문집
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• 제3권4호
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• pp.191-195
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• 2007

The optical disc drive has used a high NA objective lens and a shorter wavelength laser diode for high recording density. But high NA and shorter wavelength cause several margins to become short. Focusing and tracking servo has to be more accurate and active tilt compensation mechanism is also needed for coma aberration compensation. In this paper, we proposed 3-axis moving magnet type actuator. For 3-DOF motion, moving coil actuator has to be equipped with 6 wires for supplying 3 independent signals. However, moving magnet type actuator doesn't need to change the configuration of wires because coils are in stator. So, we added a tilt mechanism to the 2-axis moving magnet actuator which is designed in previous research. Addition of the tilt mechanism cuts down the focus sensitivity. So, maximization the tilting sensitivity and securing the focusing sensitivity are objectivities of this research. DOE (design of experiments) procedures of electromagnetic circuit are performed for parameter study and the optimization is also performed to maximize the tilt sensitivity. And then the final design is suggested and its performance is verified by FE simulation.

• 정보저장시스템학회논문집
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• 제4권1호
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• pp.23-28
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• 2008

In this paper we suggested the moving magnet type actuator for optical disc drive which has high frequency of flexible mode. Generally, moving magnet type actuator has the advantage for increase the frequency of flexible mode. But it has low driving sensitivity due to the weight of its moving part. To overcome this shortcoming, we designed the model with the closed electromagnetic circuit for tracking direction. In addition, we improved the driving sensitivity and frequency of flexible mode by using of DOE (design of experiment) procedure for EM circuit. Consequently, it is verified that final designed model satisfied with the desired specifications.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권1호
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• pp.21-26
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• 2006

This paper deals with the dynamic analysis and experiments of moving-magnet linear actuator with/without spring. On the basis of two dimensional (2-D) analytical solutions and experiments, control parameters such as thrust constant, back-emf constant, inductance and resistance are obtained. And then, dynamic simulation algorithm is established from the voltage and motion equation. Finally, for various values of frequency, dynamic simulation results for characteristics of current and displacement of moving-magnet linear actuator with and without spring are presented and confirmed through the experiments. In particular, This paper applies the PWM voltage waveform obtained from a DSP for bidirectional voltage drive to the actuator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.848-851
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• 2007

Recently, as the demand of the information storage devices with large storage capacity such as BD(Blu-ray Disk) and HDTV(high-definition television) is increased, the optical storage devices are also required to have fast data transfer rate and large storage capacity. To satisfy these requirements, the actuator for optical disk drive should have high flexible mode frequencies for system stability. In this paper, we suggested a moving magnet type actuator having high flexible mode frequency. However, the moving magnet type actuator does not have sufficient driving sensitivities due to the weight of its moving part. To improve driving sensitivities, we designed the model with the closed electromagnetic circuit for tracking direction. In addition, driving sensitivities and flexible mode frequencies were improved by using DOE(Design of Experiments) for magnetic circuit and modifying the lens holder. Consequently, it is confirmed that the designed model is satisfied with the desired specifications.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권2호
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• pp.63-68
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• 2004

This paper presents an approach to optimum design of Moving Magnet Type Linear Oscillatory Actuator(MM-LOA). The Finite Element Method is applied to characteristic parameters for characteristic analysis and in order to reduce modeling time and efforts, the moving model node technique is used. In addition the neural network is used to reduce computational time of analysis according to changing design variable. To confirm the validity of this study, optimum design results are compared with results of analysis procedure that is verified by experiment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.780-785
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• 2001

A moving-magnet type pickup actuator is proposed, which has the back-yoke to improve th sensitivity. Through the magnetic path analysis, we can find that the flux density is increased i the air gap by the pole assignment of magnet and the adding of back-yoke can reduce the flu leakage and induce 40％ up of flux density. Experimental results show that the sensitivity i improved in the tracking direction, however, the improvement doesn't occur in the focusing direction. Finally, the compensation performance is tested in HD-DVD system. And it is verifie that the actuator can compensate the disc tilt of ${\pm}$0.7$^{\circ}$.