• 한국정밀공학회지
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• 제21권5호
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• pp.174-181
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• 2004

This paper presents the development of a magnetostrictive microactuator. The structural and functional requirements are as follows: it must be a millimeter structure and must achieve controllable displacement with nanometer resolution. Finite Element Analysis(FEA) is used to determine the structure with the most uniform and highest magnetic flux density along the Terfenol-D rod. The microactuator prototype 1 is designed and made based on the FEA. It is observed that the microactuator show some level of hysteresis and that it produces 25 newton in force and 3 ${\mu}{\textrm}{m}$ in displacement with 1.5 amperes of current, and resolution of 250 nm per 0.1 amperes. To improve the performance of the microactuator prototype 1, microactuator prototype 2 is made again with a permanent magnet (PM). It is observed that the microactuator prototype 2 gene.ates 3.3 ${\mu}{\textrm}{m}$ in displacement with 0.9 amperes of current. It means that the microactuator prototype 2 performs better than the microactuator prototype 1.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.917-923
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• 2001

This paper presents the fabrication and testing results of a dual stage microactuator system for fine positioning of magnetic heads in hard disk drives. An electrostatic rotary microactuator was newly designed and fabricated. The microactuator was integrated into the head gimbal assembly of a disk drive system and its dynamic characteristics were investigated. Experimental results show that natural frequency and voltage gain of the microactuator are 4.3 KHz and 25 nm/V and the dual stage microactuator system achieves the tracking accuracy of 30 nm.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.437-438
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.1063-1066
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• 1995

This paper presents a precition control of an electrostatic microactuator. For the generation of sufficient electrostatic force, a donse comb-type electrostatic microactuator is designed and manufactureed via MEMS (micro-electro-mechanical systems) process. The nonlinear plant and the linear plant of the microactuator are established through the comparison of experimental results and simulation results. A feedforward controller is designed via MATLAB simulation using the inverse function of the nonlinear plant. the experiment for the precise position tracking control is undertaken to show the control efficiency of the proposed controller.

• 대한기계학회논문집A
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• 제25권1호
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• pp.16-24
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• 2001

This paper presents an electromagnetic microactuator using the copper coil electroplated on the p+silicon diaphragm. The microactuator generates a vertical motion of the diaphragm using the radial direction, we propose a new actuator structure with twin magnets. The microactuator field in the radial direction, we propose a new actuator structure with twin magnets. The microactator shows a values of resonant frequency and quality factor in the ranges of 10.51${\pm}$0.22kHz and 46.6${\pm}$3.3, respectively. The twin magnet microactuator generates the maximum peak-to-peak amplitude of 4.4$\mu\textrm{m}$ for the AC rms current of 26.8mA, showing 2.4 times larger amplitude than the single magnet microactuator.

• 한국정밀공학회지
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• 제14권12호
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• pp.153-159
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• 1997

A thermally-driven polysilicon microactuator has been fabricated using surface micromachining techniques. It consists of P-doped polysilicon as a structural layer and TEOS(tetraethylorthosilicate) oxide as a sacrificial layer. The polysilicon was annealed for the relaxation of residual stress which is the main cause to its deformation such as bending and buckling. And newly developed HF GPE(gas-phase etching) process was also employed to eliminate the troublesome stiction problem using anhydrous HF gas and CH$_{3}$OH vapor, and successfully fabricated the microactuators. The actuation is incurred by the thermal expansion due to the current flow in the active polysilicon cantilever, which motion is amplified by lever mechanism. The moving distance of polysilicon microactuator was experimentally conformed as large as 21 .mu. m at the input voltage level of 10V and 50Hz square wave. The actuating characteris- tics are also compared with the simulalted results considering heat transfer and thermal expansion in the polysilicon layer. This microactuator technology can be utilized for the fabrication of MEMS (microelectromechanical system) such as microrelay, which requires large displacement or contact force but relatively slow response.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.865-868
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• 2001

We designed and fabricated a planner-type thermoelastic microactuator with a latch-up operation for optical switching. Latch-up actuation is prerequisite to implement an optical switch with low power consumption and high reliability. The proposed microactuator consists of four cantilever-shaped thermal actuators, four displacement linkages, two shallow arch-shaped leaf springs, a mobile shuttle mass with a micromirror, and four elastic boundaries. The structural layer of the planar microactuator is phosphorous-doped 12$\mu\textrm{m}$-thick polysilicon, and the sacrificial layer is LTO(Low Temperature Oxide) of 3$\mu\textrm{m}$thickness. The displacement of actuator is as large as 3$\mu\textrm{m}$when the length of actuation bar is 100$\mu\textrm{m}$in length at 5V input voltage. The proposed microactuators have advantages of easy assembly with other optical component by way of fiber alignment in the substrate plane, and its fabrication process features simplicity while retaining batch-fabrication economy.

• 대한기계학회논문집A
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• 제25권3호
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• pp.424-433
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• 2001

We present a new electrostatic repulsive-force microactuator using a lateral repulsive force induced by an asymmetric distribution of electrostatic field. The lateral repulsive force has been characterized by a simple analytical equation, derived from a finite element simulation. A set of repulsive force polysilicon microactuators has been designed and fabricated by a 4-mask surface-micromachining process. Static and dynamic micromechanical behavior of the fabricated microactuators has been measured at the atmospheric pressure for a varying bias voltage. The static displacement of the fabricated microactuator, proportional to the square of the DC bias voltage, is obtained as 1.27 $\mu\textrm{m}$ for the DC bias voltage of 140V. The resonant frequency of the repulsive-force microactuator increases from 11.7 kHz to 12.7 kHz when the DC bias voltage increases from 60V to 140V. The measured quality-factor varies from 12 to 13 for the bias volatge range of 60V∼140V. The characteristics of the electrostatic repulsive-force have been discussed and compared and compared with those of the conventional electrostatic attractive-force.

• Journal of Advanced Marine Engineering and Technology
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• 제40권7호
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• pp.605-612
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• 2016

버블젯 타입 마이크로 엑츄에이터의 설계변수에 따른 유동특성에 관한 수치해석적 연구를 수행하였다. 수치 모델은 저장소로 부터의 잉크 유동과 기포의 성장 및 소멸, 노즐을 통한 액적의 토출과 리필 과정을 포함한다. 기포의 거동은 전체 엑츄에이터의 성능에 중요한 영향을 미치는 요소이기 때문에, 본 연구에서는 open pool 해석을 통하여 기포의 성장과 소멸 및 소멸시의 캐비테이션 현상에 대해 살펴보았다. 또한 마이크로 엑츄에이터의 노즐 형상의 변화, 챔버와 리스트릭터의 기하학적 변화에 따른 액적의 토출과 잉크 리필과정에 대한 수치예측을 수행하였다. 설계변수의 변화에 따른 수치해석의 결과는 마이크로 엑츄에이터의 성능특성을 예측할 수 있으며 또한 마이크로 엑츄에이터의 최적설계에 유용하리라 판단된다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권11호
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• pp.581-588
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• 2001

This paper presents theoretical and experimental study on the quality-factor of the laterally oscillated electrostatic microactuator, driven by a lateral repulsive-force generated by the asymmetry of planar electric field. The quality-factor of the repulsive-force microactuator using a creeping flow model of the ambient air is evaluated. By filling the simulation results of damping force, we evaluate the dimensionless damping force, $\alpha$, thereby obtaining an analytical damping force, F, in the form of $F=\mu\; \alphaUL,\; where\; \mu,$ U and L denote the air viscosity, the velocity and the characteristic length of the movable electrodes. The measured quality-factor increases from 12 to 13 for the DC bias voltage increased from 60V to 140v. The theoretical quality-factor estimated from the creeping flow model increases from 14.9 to 18.7. Characteristics of quality-factor of the repulsive-force microactuator have been discussed and compared with those of the conventional attractive-force microactuator.