• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.731-734
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• 2005

Generally, characteristics of electromechanical actuators are coupled with the mechanical and the electrical properties. Important mechanical parameters of these actuators are the achievable force and displacement in the presence of electric field. These mechanical parameters are related to the stress and strain of the materials and the actuator geometry. This paper presents how to measure the blocked force by using the micro-balance. The blocked force is defined as the force produced by the transducer under an applied voltage when the tip is constrained to zero motion. Also, a theoretical force by using the cantilever beam model is calculated under elastic domain. From the sample of 4 cm $\times$ 1 cm $\times$ 20 $\mu$m, the blocked farce measured from the equipment is 20.3 $\mu$N at 8 V$_{DC}$. By comparing it with the theoretical value, 24.9 $\mu$N, the blocked force measurement is acceptable. The furce measurement is also investigated with different AC electric fields and the frequency.

• 한국전기전자재료학회논문지
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• 제34권6호
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• pp.401-415
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• 2021

Soft robots are promising devices for applications in drug delivery, sensing, and manufacturing. Traditional hard robotics are manufactured with rigid materials and their degrees of motion are constrained by the orientation of the joints. In contrast to rigid counterpart, soft robotics, employing soft and stretchable materials that easily deforms in shape, can realize complex motions (i.e., locomotion, swimming, and grappling) with a simple structure, and easily adapt to dynamic environment. Among them, the magnetic actuators exhibit unique characteristics such as rapid and accurate motion control, biocompatibility, and facile remote controllability, which make them promising candidates for the next-generation soft robots. Especially, the magnetic actuators instantly response to the stimuli, and show no-hysteresis during the recovery process, essential for continuous motion control. Here, we present the state-of-the-art fabrication process of magnetically controllable nano-/micro-composites, magnetically aligning process of the composites, and 1-dimensional/multi-dimensional multimodal motion control for the nextgeneration soft actuators.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.91-91
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• 2009

Piezoelectric micro-pump should contain the physical running parts like check valves for acquiring the unilateral motion of fluid from the alternating motion of actuators. But the check valves raise many problems such as abrasion or exhaustive destruction by the recursive mechanical displacement To solve these problems, we propose a novle type piezoelectric valveless micro-pump using peristaltic motion due to the traveling wave excitation. Proposed pump model is consisted of two piezoelectric ceramic plates, elastic metal body, caps for covering flow path, rubber rings for sealing tightly and disk springs for the pressurization of pump body.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1286-1289
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• 2004

A new thermal bimorph actuator for large out-of-plane displacement is designed, fabricated and tested. The deflecting beam is composed of polyimide, heater, and polyvinyl difluorides with tetrafluoroethylene(PVDF-TrFE). The large difference of coefficient of thermal expansion(CTE) of two polymer layers (polyimide and PVDF-TrFE) can generate a large deflection with relatively small temperature rising. Compared to the most conventional micro actuators based on MEMS(micro-electro mechanical system) technology, a large displacement, over 1 mm at 20 mW, could be achieved. The proposed actuator can find applications where a large vertical displacement is needed while keeping compact overall device size, such as a micro zooming lens.

• 마이크로전자및패키징학회지
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• 제24권2호
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• pp.29-35
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• 2017

본 논문에서는 서브 밀리미터 직경의 카테터 표면 위에 금속 마이크로 와이어를 접착하는 공정을 연구하였다. 최근 유연 전자 디바이스 분야는 유연한 평면 폴리머 기판과 그 기판 위의 마이크로 전극 공정이 계속해서 연구되고 있다. 하지만, 의료 분야에서는 카테터와 같이 곡면을 가진 기판이 중요하다. 특히 카테터 중에서도 여러 한계점을 가진 뇌혈관 수술을 개선하기 위한 서브 밀리미터의 직경을 가진 조향 가능한 카테터의 중요성이 대두되고 있다. 이러한 카테터를 구현하기 위해 조향을 위한 엑추에이터들은 연구가 되고 있지만 이를 구동하기 위한 배선 연구는 진행된 바가 없다. 그러므로 본 연구에서는 이러한 서브 밀리미터 카테터 위에 마이크로 금속 와이어를 접착하는 공정을 개발하였다. 적합한 지그를 설계함으로써 마이크로 와이어를 서브 밀리미터 직경의 카테터에 정렬한다. 그리고 자외선 경화 시스템과 상용품을 이용하여 공정 시간 및 공정 비용을 감소시켰다. 상용품으로 골드 마이크로 와이어, 자외선 경화 에폭시, 자외선 램프 그리고 서브 밀리미터 카테터를 이용하였다. 공정 후 카테터는 광학 현미경, 저항 측정기, 만능 시험기를 통해 분석하였다.

• 대한기계학회논문집
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• 제17권7호
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• pp.1731-1739
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• 1993

An application of Scanning Tunneling Microscopy(STM) is investigated for the measurement of 3-dimensional profiles of the macro-machined patterns of which critical dimensions lie in the range of submicrometers. Special emphasis of this investigation is given to extending the measuring ranges of STM upto the order of several micrometers while maintaining superb nanometer measuring resolution. This is accomplished by correcting hysteresis effects of piezoelectric actuators by using non-linear compensation models. Detailed aspects of design and control of a prototype measurement system are described with some actual measuring examples in which fine It patterns can successfully be traced with a resolution of 1 nanometer over a surface range of $4{\times}2$ micrometers.

• 한국공작기계학회논문집
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• 제18권2호
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• pp.137-143
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• 2009

This paper presents the fabrication of inchworm motor for high precision actuator system of large displacement and high force. The inchworm motor consists of a extend actuator that provides displacement of tool guide and two clamping actuators which provide the holding force. In order to avoid the PZT fracture, design of pre-load housing was conducted by flexure hinge structure, because PZT actuator has low tensile and shear. To design the pre-load housing and optimize the clamping mechanism, the static and dynamic analysis were conducted by finite element method. From these results, a prototype of the inchworm motor was fabricated and dynamic characteristic with respect to the various frequency was tested. The maximum velocity of the inchworm motor was $41.1{\mu}m/s$ at 16Hz.

• Structural Engineering and Mechanics
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• 제56권3호
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• pp.461-472
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• 2015

In this paper, the nonlinear static response of curled cantilever beam actuators subjected to the one-sided electrostatic field is focused on. By assuming the deflection function of electrostatically actuated beam, analytical approximate solutions are established via using Galerkin method to solve the equilibrium equation. The Pull-In voltages which determine the stability of the curled beam actuators are also obtained. These approximate solutions show excellent agreements with numerical solutions obtained by the shooting method and the experimental data for a wide range of beam length. Expressions of these analytical approximate solutions are brief and could easily be used to derive the effects of various physical parameters on MEMS structures.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권2호
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• pp.140-148
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• 2000

In this paper, using surface micromachining technology with thick photoresist and aluminum, an SLM(Spatial Light Modulator), which is applied to the fields of adaptive optics and pattern recognition system, was fabricated and the electromechanical properties of the fabricated micro SLM are measured. In order to maximize fill-factor and remove mechanical coupling between micro SLM actuators, the micro SLM is composed of three aluminum layers so that spring structure and upper electrode are placed beneath the mirror plate, and $10\times10$ each mirror plate is individually actuated. Also, the micro SLM was designed to be able to modulate phase and amplitude of incoming light in order to have a continuity of phase modulation of incoming light. In the case of amplitude and phase modulation, maximum vertical displacement is 4$\mum$, and maximum angular displacement is $\pm4.6^{\corc}$ respectively. The height difference of the fabricated mirror plate was able to be reduced to 1100A with mirror plate planarization method using negative photoresist(AZ5214). The electromechanical properties of the fabricated micro SLM were measured with the optical measurement system using He-Ne laser and PSD(position sensitive device).

• 한국정밀공학회지
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• 제12권2호
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• pp.48-58
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• 1995

A micro positioning system using piezoelectric actuators have very wide application region such as ultra-precision machine tool, optical device, measurement systen. In order ro keep a high precision displacement resolution, they use a position sensor and feedback the error. From the practical point of view, a high-resolution displacement sensor system are very expensive and difficult to guarantee such sensitive sensors work properly in the hard opera- tion environment of industry. In this study, a micro-positioning grinding table which does not require position sensor but uses piezoelectric voltage feedback, has been developed. It is driven by hystersis-considering reference input voltage which calculated from computer and then uses actuator/sensor characteristics of piezoelectric materials. From the result of experiments we proved a fast and stable response of micro-positioning system and suggested efficient technique to control the piezoelectric actuator. And through grinding experiments, it is revealed that a characteristics of ground surfaces transient to plastic deformation as extremely small depth of grinding.