• Title/Summary/Keyword: 마이크로 구동기

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Nonlinear Vibrations of Piezoelectric Microactuators in Hard Disk Drives (하드디스크 드라이브용 압전형 마이크로 액추에이터의 비선형 진동 특성)

  • Jeong, Deok-Yeong;Lee, Seung-Yeop;Kim, Cheol-Sun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.12
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    • pp.2002-2008
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    • 2001
  • Nonlinear vibration characteristics of a piezoelectric-type micro actuator used for hard disk drives are experimentally studied. The nonlinear characterisitics include hysteresis, superharmonic resonance, jump phenomenon, and shifting of natural frequencies. The vibration modes and frequencies of the commercial actuator of the Hutchinson's Magnum series are measured using a laser vibrometer. From harmonic excitation to the PZT acturator, we observe interesting hysteresis patterns with 3 times input frequency. It is shown that the micro actuator has the typical 3 times superhamonic resonances coupled to the first torsional and sway modes of the suspension.

Adhesion between Carbon Nanotube Arrays with Different Contact Area Measured Using Microactuator (마이크로 구동기를 이용한 탄소나노튜브 어레이의 접촉 면적에 따른 점착력 측정)

  • Choi, Jungwook;Kim, Jongbaeg
    • Transactions of the Society of Information Storage Systems
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    • v.10 no.1
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    • pp.14-18
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    • 2014
  • Adhesion between carbon nanotube (CNT) arrays is measured and characterized for number of different contact areas. The CNT arrays are directly grown on an electrostatic microactuator, and they make contact with each other during the growth process. The pull-out force is precisely applied by the microactuator while the contact status is identified by measuring electrical resistance between the CNT arrays. We have designed different contact areas of 1000, 6000, and 8500 ${\mu}m^2$ between the CNT arrays, and the corresponding adhesion increases from 0.9 to 3.7 ${\mu}N$ as the contact area increases.

Fabrication of an Electrostatic Micro Actuator Using p+ Diaphragm As an Electrode (p+ 박막을 전극으로 한 정전형 마이크로 구동기의 제작)

  • Han, Sang-Woo;Yang, Eui-Hyeok;Yang, Sang-Sik
    • Proceedings of the KIEE Conference
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    • pp.141-143
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    • 1994
  • In this paper, an electrostatic micro-actuator is fabricated using flat p+ diaphragm. To avoid the buckling of the flat p+ diaphragm, the processes are designed appropriately. The fabrication processes of the actuator are the anisotropic etching with EPW, the boron diffusion process, Al deposition and the silicon to glass bonding using the negative photoresist. The distance between the p+ and Al electrodes is $10{\mu}m$, and the thickness of the p+ diaphragm is $2{\mu}m$. The measurement of the characteristic of the actuator is performed at 50V. The center displacement of the diaphragm is $1.5{\mu}m$ at 10Hz. In comparison with the experimental data of the actuator with corrugated diaphragm, it is confirmed that the actuator with flat diaphragm is more effective than that with corrugated one in the small deflection region.

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Fabrication of a Micro actuator with p+ Si cantilevers for Optical Devices (p+ Si 외팔보 구조를 이용한 광학 소자용 마이크로 구동기)

  • Park, Tae-Gyu;Yang, Sang-Sik
    • Proceedings of the KIEE Conference
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    • pp.2236-2238
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    • 2000
  • The paper represents the fabrication of an electrostatic micro actuator for optical devices. The micro actuator consists of a plate suspended four p+ silicon cantilevers and an electrode on a glass substrate. The cantilever curls down because of the residual stress gradient in p+ silicon. When input voltage is applied between the p+ cantilevers and the electrode. the cantilevers are pulled toward the electrode by the electrostatic force. The displacement of the plate is measured with a laser displacement meter for various input voltage and frequencies.

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Fabrication of a Micro Actuator with p$^+$ Si Cantilevers for Optical Devices (p$^+$ Si 외팔보 구조를 이용한 광학 소자용 마이크로 구동기의 제작)

  • Park, Tae-Gyu;Yang, Sang-Sik
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.5
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    • pp.249-252
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    • 2001
  • The paper represents the design and fabrication of an electrostatic micro actuator with $p^+$,/TEX> Si cantilevers. The micro actuator consists of a plate suspended by four $p^+$,/TEX> silicon cantilevers and an electrode on a glass substrate. The $p^+$,/TEX> Si structure is fabricated by the boron diffusion process and the anisotropic wet etch process. The cantilevers of the micro actuator curl down because of the residual stress gradient in $p^+$,/TEX> silicon. When the electrostatic forec is applied to the $p^+$,/TEX> cantilevers, the vertical displacement of the plate can be achieved. The deflection of the cantilever due to the residual stress gradient and the vertical displacement by electrostatic force were calculated. The displacement of the plate was measured with a laser displacement meter for various input voltages and frequencies. The feasibility of the proposed micro actuator for the applications to optical pickup devices or optical communication devices was confirmed by the experiments.

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Development of Micro-bellows Actuator Using Micro-stereolithography Technology (마이크로 광 조형 기술을 이용한 마이크로 밸로우즈 액추에이터의 개발)

  • Kang H.W.;Lee I.H.;Cho D.W.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.615-618
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    • 2005
  • All over the world, many kinds of micro-actuators were already developed for various applications. The actuators are using various principles such as electromagnetic, piezoelectric and thermopneumatic etc. The most of the micro-actuators have been made using 2D based MEMS technology. In these actuators, it is difficult to drive 3-dimensional motion. This characteristic gives the limit of actuator application. However, micro-stereolithography technology has made it possible to fabricate freeform three-dimensional microstructures. In this technology, 2-dimensional micro-shape layer is cumulated on the other layers. This layer-by-layer process is the main principle to fabricate 3-dimensioal micro-structures. In this research, a micro-bellows actuator that is vertically moving was developed using the micro-stereolithography technology. When pressure was applied into the bellows, a non-contact actuating motion is generated. For actuation experiment, syringe pump and laser interferometer were used for applying pressure and measuring the displacement. Several hundreds micro-scale actuation was observed. And, to demonstrate the feasibility of proposed actuation principle, in this research, a micro-gripper was developed using half-bellows structure.

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Design of Digital Tracking Controller based on Disturbance Observer for Micro Electrostatic Actuator with Nonlinearity (비 선형 요소를 갖는 정전 마이크로 구동기의 외란 관측기에 기초한 디지털 추종 제어기 설계)

  • Choe, Hyun-Taek;Suh, Il-Hong
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.6
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    • pp.773-780
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    • 1999
  • A digital tracking controller is proposed for micro electrostatic actuator with input nonlinearity, where disturbance observer is utilized in cooperation with inverse function. Generally the disturbance observer is announced to be robust to modeling uncertainty, and external disturbance. But, when the nonlinearity exists in the systems, the disturbance observer may not directly be applied to that system, because the nonlinearity may destabilize the overall system. Therefore, first, we linearize the nonlinear input characteristics of micro electrostatic actuator by the use of inverse function. Secondly, we apply disturbance observer to approximately linearized system for eliminating the residuals of nonlinearity and the modeling uncertainty. Then, we get the good properties of the disturbance rejection as well as the robustness due to the own nature of disturbance observer. In this case, we propose a sufficient condition for the robust stability of overall systems. Furthermore, we discuss the problem that may be exposed when disturbance observer is applied to the internally stable system with saturation, and analyze two methods to overcome input saturation problem in the sense of internal stability. Simulations have been carried out to show the effectiveness of the proposed controller.

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Detection of Tool Failure by Wavelet Transform (PDMS를 이용한 마이크로 구동기의 제작 및 평가)

  • Lee, Dong Weon;Park, Jong Sung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.7 no.2
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    • pp.72-77
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    • 2008
  • In this study, we propose and develop PDMS-based modular actuators. The microactuator which looks like a small insect uses thermal expansion power of the PDMS (polydimethylsiloxane; $sylgar^{(R)}$ 184 silicone elastomer). The PDMS-based microactuator provides a large displacement due to a high thermal expansion coefficient (approximately 310ppm). The microacruator with 1mm length $350{\mu}m$ width is optimized by using a numerical analysis. The shape of the PDMS actuatoris variously designed. They are placed at several positions to find the optimal position that provides a high transformation ratio. The PDMS-based microactuators are fabricated using a conventional micromaching technique. The fabricated microactuator is heated using a hot-plate. The actuator displacement is measured as a function of temperature from $27^{\circ}C$ to $300^{\circ}C$. The experimental results are compared to the simulation result. When heating temperature up to $300^{\circ}C$ is applied to the PDMS actuator, each V-groove-shaped joint is actuated $30{\mu}$ mat $300^{\circ}C$. Anotherdesign of the microactuator has a maximum displacement of about 656mm.

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Adaptive Feedforward Rejection of Microactuator Resonance in Hard Disk Drive Dual-stage Actuator Servo (하드디스크 드라이브 마이크로 구동기의 공진 영향 제거를 위한 적응 피드포워드 제어)

  • Oh, Dong-Ho;Lee, Seung-Hi;Baek, Sang-Eun;Na, Hee-Seung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1596-1600
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    • 2000
  • We propose a novel adaptive feed forward controller (AFC) design method for rejecting the effect of micro actuator resonance in the design of dual-stage actuator servo systems for disk drives. Microactuator's resonance is one of important issues in dual-stage actuator servo, which varies up to ${\pm}10%$ per product and even during operation. We derive an adaptive algorithm for the proposed AFC design, which turns out to be identical to the delayed-x LMS algorithm which is a special form of the filtered-x LMS algorithm. In the algorithm, coefficients of the AFC are adapted by the residuals of constrained structure defined in such a way that the coefficients become time invariant. Contrary to the conventional AFC, it considers the phase delay of closed-loop transfer function at resonance frequency for system stability. We also apply an adaptive algorithm with frequency tracking capability. The frequency tracking algorithm is induced by the orthogonality of AFC coefficients. Computer simulations are carried out to demonstrate effect of the proposed AFCs.

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