• 한국정밀공학회지
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• 제23권9호
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• pp.179-189
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• 2006

Recently the electrostatic 2-axis MEMS stages have been fabricated f3r the purpose of an application to PSD (Probe-based Storage Device). However, all of the components (platform, comb electrodes, springs, anchors, etc.) in those stages are placed in-plane so that they have low areal efficiencies such as a few percentage, which is undesirable as data storage devices. In this paper, we present a novel structure of an electrostatic 2-axis MEMS stage that is characterized by having a large areal efficiency of about 25%. For obtaining large area efficiency, the actuator part consisting of mainly comb electrodes and springs is placed right below the platform. The structure and operational principle of the MEMS stage are described, followed by a design and analysis, the fabrication and measurement results. Experimental results show that the driving ranges of the fabricated stage along the x and y axis were 27$\mu$m, 38$\mu$m at the supplied voltages of 65V, 70V, respectively and the natural frequencies along x and y axis were 180Hz, 310Hz, respectively. The total size of the stage is about 5.9$\times$6.8mm$^2$ and the platform size is about 2.7$\times$3.6mm$^2$.

• 한국정밀공학회지
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• 제19권9호
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• pp.41-50
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• 2002

Optical disk system aiming at fast data transfer rate and high-density recording requires the improvement in performance of the pickup head. Especially, the pickup actuator needs better linearity and stability. So, a lever actuator for optical disk is proposed. In this paper, the role of lever and its structure are discussed and the flexure hinge is introduced to enhance the precise movement. Using the Newoton's method, the motion of equation for the lever actuator is obtained. The results are compared with the analysis results by the FEM (Finite Element Method) for the vibration and the magnetic field. Consequently, the lever actuator has the 2"d system characteristics in 3-axis moving directions and superior stability for the external vibration.tion.

• 한국공작기계학회논문집
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• 제15권3호
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• pp.82-90
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• 2006

Recently the electrostatic 2-axis MEMS stages have been fabricated for the purpose of an application to PSD (Probe-based Storage Device). However, all of the components(platform, comb electrodes, springs, anchors, etc.) in those stages are placed in-plane so that they have low areal efficienceis, which is undesirable as data storage devices. In this paper, we present a novel structure of an electrostatic 2-axis MEMS stage that is characterized by having large area platform. for obtaining large area efficiency, the actuator part consisting of mainly comb electrodes and springs is placed right below the platform. The structure and operational principle of the MEMS stage are described, followed by a design procedure, structural and modal analyses using FEM(Finite Element Method). The areal efficiency of the MEMS stage was designed to be about 25%, which is very large compared with the conventional ones having a few percentage.

• 대한기계학회논문집A
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• 제25권9호
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• pp.1341-1349
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• 2001

In this paper, 3 D.O.F. actuator, which has three degrees of freedom in one joint, is proposed. The proposed 3 D.O.F. spherical actuator is composed of the rotor and atator. The upper plate of the stator supports the rotor and five electromagnets are located at the base of the stator. The rotor has two permanent magnets, and each rotational axis of the rotor gimbal system is supported by the bearing. To find out the governing equations for the torque generation, Coulombs law and Lorentz force with respect to magnetism is applied. As the experimental results, if the distance between electromagnet and permanent maget is far enough, the force between these magnets can be expressed from current of coils and z-axial distance. For the purpose of control 3 D.O.F. actuator, PID control law is applied. The experimental results are presented to show the validity of the proposed 3 D.O.F. actuator.

• 한국항공우주학회지
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• 제41권2호
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• pp.107-119
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• 2013

네 개의 반작용휠과 두 개의 제어모멘트자이로를 이용하여 2축 고기동을 포함한 3축 자세제어방법을 연구하였다. 두 개의 제어모멘트자이로 때문에 발생하는 특이점에 대해 살펴보고 특이점을 탈출하는 방법을 제안하였다. 이 결과를 토대로 고기동을 위한 구동기 제어방법을 제안하였다. 아울러 자세제어 전후의 반작용휠과 제어모멘트자이로의 모멘텀이 유지되도록 하는 구동기 모멘텀 관리방법도 제안하였다. 시뮬레이션을 통하여 설계된 제어기법이 위성의 3축 제어 및 2축에 대한 고기동을 달성하며 구동기의 모멘텀도 보전하는 것을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.775-779
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• 2003

Recently, a new type actuator using multi-pole magnet has been developed for high-density and high-speed disk drive, which can be achieved higher sensitivity than a conventional actuator for applying one-pole magnet. However, it is very difficult for the actuator of multi-pole magnet to meet simultaneously the optimal design condition for reducing rolling mode effect and improving driving sensitivity because the force center is different from the mass center In this paper, First We propose the new shape coil for tracking which can reverse moment additionally in tracking motion, Next we achieve the optimal design to reduce phase disturbance and peak gain at the rolling mode frequency. Finally, the validity of the proposed methods is proved from experimental results.

• 한국정밀공학회지
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• 제21권3호
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• pp.155-162
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• 2004

This paper presents the fabrication procedure and the experiments for the 3-axis fine positioning stage proposed in［1］. First, the dynamic characteristics of the actuator and the stage are tested with the preload changed in order to validate the stage design specifications. Secondly, the performance of the stage is also evaluated on the accuracy associated with linear positioning, angular error, and straightness error. Experimental results show that the developed stage is accurate enough to be used for nanometer positioning. Through the analysis and experiment, the developed fine positioning stage are found to have a long stroke due to the magnetically preloaded PZT actuators, the minimum motion crosstalk due to the use of a ball contact mechanism and the compact design.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권3호
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• pp.149-155
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• 2006

This paper presents a torsional micromirror detached from PZT actuators (TMD), whose rotational motion is achieved by push bars in the PZT actuators detached from the micromirror. The push bar mechanism is intended to reduce the bending, tensile and torsional constraints generated by the conventional bending bar mechanism, where the torsional micromirror is attached to the PZT actuators (TMA). We have designed, fabricated and tested prototypes of TMDs for single-axis and dual-axis rotation, respectively. The single-axis TMD generates the static rotational angle of $6.1^{\circ}$ at 16 VDC, which is 6 times larger than that of single-axis TMA, $0.9^{\circ}$. However, the rotational response curve of TMD shows hysteresis due to the static friction between the cover and the push bar in the PZT actuator. We have shown that 63.2% of the hysteresis is due to the static friction caused by the initial contact force of the PZT actuaor. Without the initial contact force, the rotational response curve of TMD shows linear voltage-angle characteristics. The dual-axis TMD generates the static rotational angles of $5.5^{\circ}$ and $4.7^{\circ}$ in x-axis and y-axis, respectively at 16 VDC. The measured resonant frequencies of dual-axis TMD are $2.1\pm0.1$ kHz in x-axis and $1.7\pm0.1$ kHz in y-axis. The dual-axis TMD shows stable operation without severe wear for 21.6 million cycles driven by 16 Vp-p sinusoidal wave signal at room temperature.

• 정보저장시스템학회논문집
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• 제1권2호
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• pp.121-126
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• 2005

Recently, an optical disc system has been proposed using blue laser diode, high NA objective lens and groove only disc structure. A new method is needed to readout CD and DVD in this Blu-Ray Disc Recorder. In order to readout CD and DVD in Blu-Ray Disc Recorder, we adopted dual-lenses actuator in consideration of optical utilization efficiency, optical performance and insurance of sufficient W.D(working distance). This dual-lenses actuator has two objectives in radial direction, one is for CD/DVD and the other is for BD. We had to solve the induced problems of collision between disc and lens, DC tilt increase, AC tilt increase, 2nd resonance deterioration and AC sensitivity drop caused by disposing two lenses in an actuator. Also we developed high response twin- objective actuator with radial tilt function to apply high-speed BD Recorder or BD Player. Consequently we presented that two kinds of dual-lenses actuators for BD Recorder have been possessed good performance in 3 axis directions. And we measured eye patterns of CD, DVD and BD by using one BD optical pick-up with dual-lenses actuator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.378-380
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• 2002

There has been lower the tilt margin by the increase of coma aberration due to the reduction of wave-length and the increase of numerical aperture for high density recording. The RF signal degradation is increased as the decrease of tilt margin. To compensate the tilt margin, the optical pick-up actuator for high-speed CD/DVD re-writable system should be able to drive the radial-tilt motion. We announce that the 3-axis drive actuator for high-speed CD/DVD rewritable system. And what was more, the DC/AC sensitivities of this actuator are suitable fur the low-speed playability, the high-speed readability and the high-speed rewritability.