• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.11
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• pp.1043-1049
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• 2007

Data transfer rate and storage capacity are main criteria of the performance of the optical disk drive. The highest data transfer rate and the largest storage capacity is most desirable. To increase these performances, the actuator of the optical disk drive should have a high servo bandwidth to compensate the vibration of an optical disk. The servo bandwidth is limited by some flexible modes of the actuator, thus it is essential to increase the natural frequencies of the flexible modes. In this paper, we suggested a moving magnet type actuator having high frequencies of the flexible modes. Generally, the moving magnet type actuator has an advantage to increase the natural frequencies of the flexible modes because the moving magnet type actuator has simple structure and the Young's modulus of magnet is high. However, large moving mass and inefficiency of EM(electromagnetic) circuit cut down driving sensitivities of the actuator. To improve driving sensitivities, we designed the model with the closed electromagnetic circuit for tracking direction. In addition, driving sensitivities and the natural frequencies of the flexible modes were improved by using DOE(design of experiments) for electromagnetic circuit and modifying the lens holder.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.8
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• pp.1308-1316
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• 2001

A hybrid type master system is proposed to take the advantage of the link mechanism and magnetic levitation mechanism without using a force sensor. Two different types of electromagnetic actuators, moving coil type and moving magnet types are used to drive the master system which is capable of 4-DOF actuation. It is designed that the rotation motions about x-y axis are decoupled and the whole system is represented by simple dynamic equations. The force reflection is achieved by using the simple relation between the force and applied current and position. The simulation and experimental results are presented to show its performance.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.107-109
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• 2003

본 논문은 전력기기 중 저압 재폐로(Recloser) 차단기에 대한 FEM을 이용한 조작부 구동메커니즘의 동작특성에 대해 연구하였다. 중 저압 차단기는 크게 차단부와 조작부로 분리할 수 있는데 조작부메커니즘은 동작특성의 영향을 많이 받기 때문에 차단동작특성이 좋고 신뢰성 및 반복성이 우수한 영구자석형 마그네틱 액추에이터를 사용하였다. 그리고, 정확한 동작 특성 해석을 위해 물질의 비선형 특성을 고려하였고, 외부회로와 결합하여 2-D FEM을 통한 전자계 해석을 하였다. 또한, 실험을 통한 최종적인 기계적인 힘과 FEM으로 해석한 액추에이터의 힘을 비교 검증하였다.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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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.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.2 s.95
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• pp.156-160
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• 2005

We design a new actuator of 3-axis motion for high performance optical devices. The actuator makes it possible to control the tilting motion by using moving magnet and PCB-coil, which have benefits in price and manufacturing. To predict the characteristics of the actuator, especially the effect of moving magnet, finite element method and electro-magnetic analysis were used. By comparing simulation data with experimental results, we verified the accuracy of the simulation and the superiority of the present.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.56-58
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• 2006

본 논문은 새로운 구조를 갖는 소형 셔터장치의 설계에 관하여 기술한다. 휴대용 전화기 둥의 소형 카메라 모듈에 탑재 가능한 박형의 구조로, 한 쌍의 영구자석이 상하 방향에 위치하여 구동부를 형성한다. 유한요소해석을 통해 제안된 액추에이터의 위치에 따른 토크를 계산하고, 동작 특성 향상을 위하여 세부구조를 개선하였다. 최종 모델의 토크특성을 해석하고 종래 셔터장치의 실험값과 비교/분석하여 설계 모델의 타당성을 검증하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.8
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• pp.788-794
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• 2009

Various types of latch designs for hard disk drives using load/unload mechanism have been introduced to protect undesired release motions of a voice coil motor(VCM) actuator from sudden disturbances. Recently, various inertia-type latches have been widely used because locking performance is better than that of other types of latch. However there has been a limit in the inertia type in order to guarantee perfect latch and unlatch operations because of changes in latch/unlatch conditions due to mechanical tolerance and temperature-dependent friction. In this paper, a reliable and robust magnetic latch mechanism is proposed through only simple modifications of coil and yoke shapes in order to overcome the mechanical limit of current inertia-type latches. This new magnetic latch does not have only a simple structure but it also ensures reliable operations and anti-shock performance. The operating mechanism of the proposed latch is theoretically analyzed and optimally designed using an electromagnetic simulation.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.49-51
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• 2009

This paper deals with the analysis on eddy current losses for cylindrical linear oscillatory actuator (LOA) with Halbach array mover according to voltage waveform. This paper presents analytical procedures for calculation of eddy current losses using Poynting theorem. On the basis of the magnetic vector potential and a two-dimensional (2-d) cylindrical coordinate system, this paper derived analytical solutions of eddy current tosses using phase current analysis. The eddy current losses of each harmonic obtained by fast Fourier transform (FFT) analysis of phase current are compared with results obtained from finite-element method (FEM). Particularly, this paper shows that the eddy current losses of cylindrical LOA according to square voltage waveform are more significant than those according to sinusoidal voltage waveform.