• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.153-153
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• 2004

반도체 공정과 같은 정밀 위치제어가 요구되는 분야에서 높은 해상도와 큰 구동 거리를 가지는 정밀 스테이지의 수요가 점차 증가하고 있다. 압전 액추에이터에 의해 구동이 되는 정밀 스테이지는 이와 같은 용도에 적합한 것으로 여겨지고 있고, 이에 대한 연구가 많이 이루어지고 있다. 본 연구에서는 압전 액추에이터로 구동하는 2축 정밀 스테이지가 연구 대상이다. 요구되는 스테이지 변위가 커서 압전 액추에이터의 변위만으로 원하는 변위를 얻을 수 없으므로, 유연힌지가 포함된 레버구조를 이용하여 최초 변위를 3 배 이상으로 확대시키는 구조로 되어있다.(중략)

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.200.2-200.2
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• 2005

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1015-1020
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• 2011

Nanoimprint lithography has been actively investigated. This method can replicate a nanopatterned master stamp onto a thin polymer film on a silicon substrate and so on. In this study, a square-shaped hollow piezoelectric actuator is presented, which is newly developed. This actuator is used for driving a nanoscale stamp in nanoimprint lithography instead of a conventional electric motor. The fabricated prototype actuator has 95 layers and side lengths of 23 mm and 18 mm for the outer and inner squares, respectively. By adopting a novel process instead of the conventional forming process for fabricating a one-layer actuator, the one-layer is composed of four rectangular segments produced by sawing a ceramic film with a thickness of 0.3 mm. The basic characteristics on displacement and generation force of the fabricated prototype actuator are experimentally investigated. Furthermore, the displacement characteristics obtained by using a PI controller are tested and discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5409-5415
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• 2012

Piezo ceramic actuator is used for various industrial products such as spray, dispenser, and valve control etc. Since the deflection of the piezo ceramic element depends on the applied voltage, it is required a power amplifier with high voltage supply for driving the piezo ceramic actuators. In this paper, we develop a simple H-bridge type power amplifier and a compact flyback type high voltage switching mode power supply for piezo ceramic actuators. It is easy to adjust the amount of energy input to piezo ceramic actuator by pulse-width-modulation with H-bridge type power amplifier.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.11
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• pp.1080-1088
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• 2009

An actuator using piezoceramic material was designed in order to perform a flow control for flat plate flow. Boundary layer measurements were carried out to explore the flow disturbances by the designed actuator that was activated at low excitation frequency(15Hz). The mean velocity and fluctuation in the boundary layers were measured at $x/{\delta}^*=31.9$ downstream from the actuator tip by a one-dimensional hot-wire probe(55P14). Results reveal that low- and high-velocity regions were observed in the vicinity of the actuator center and in the outer area of the actuator respectively, and the formation of counter-rotating streamwise vortices was predicted. The fluctuations were persistently found in the outer part of the actuator and an inflection point in the spanwise gradient of the streamwise velocity was observed. Boundary layer instability was amplified at both the actuator excitation frequency and the T-S wave frequency when the actuator was excited at low frequency.

• Transactions of The Korea Fluid Power Systems Society
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• v.2 no.3
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• pp.6-11
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• 2005

A household gas valve is used for flow control of LPG(Liquefied Petroleum Gas) or LNG(Liquefied Natural Gas) of which pressure is about $200mmH_2O(\fallingdotseq\;0.0196[bar])$. Currently, two kinds of valves such as rotary type and button type are widely used in many applications. But, these valves have some problems that they are not controllable and reliable. Piezo actuation combined with modem microelectronics provides a reliable, quiet, low energy, infinitely adjustable gas valve. In this paper, gas valve using piezo actuator which are bimorph and a circle type was studied. Also, Prototype for gas valve was manufactured and characteristics of the prototype gas valve were analyzed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.250-253
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• 2004

This study deals with the microvalve, which is composed of the multilayer bender type PZT actuator, actuator controller and microvalve body. The object of this study is to develope the microvalve with multilayer bender type PZT actuator. In order to achieve this object, prototype PZT actuator and microvalve were suggested and manufactured. Also, the performance of this model was evaluated through the experiments.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1764-1765
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• 2011

피에조 액추에이터는 세라믹 소재의 압전 특성을 이용한 전기식 액추에이터로, 이에 사용되어지는 세라믹스는 전자분야의 기초재료로 다양한 연구가 이루어지고 있다. 통신기기, 의료기기, 초정밀 액추에이터, 초음파 모터 등 각종 정밀 센서와 측정 계측기기와 같이 가정용에서부터 첨단 기술 분야 까지 광범위하게 이루어지고 있다. 이와 같이 첨단 기술 분야에 각광 받고 있는 압전 소재 제품중, 본 논문에서는 국내 개발 및 시장 진입이 어려운 초정밀 액추에이터를 선택 하였으며, 전압 이송소자를 활용하기 위한 연구소단위의 연구내용을 기술하였다. 즉, 정밀 제어에 영향을 미치는 피에조의 히스테리시스를 포함한 개루프 특성을 모델링하고, 컴퓨터 시뮬레이션으로 액추에이터의 동작을 검증한 후 PID제어기를 적용하여, 이에 따른 결과와 함께 제어기를 제작하였다.

• Journal of KSNVE
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• v.5 no.3
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• pp.313-325
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• 1995

Two active/passive vibration dampers were designed to control a cantilever beam first mode of vibration. The active element was a piezoelectric polymer, polyvinlidene fluoride (PVDF). The passive damping was provided by the application of a viscoelastic layer on the surface of the steel beam. Two substantially different damper configurations were designed and tested. One damper consisted of a piezoelectric actuator bonded to one face of the beam, with a viscoelastic layer applied to the other surface of the beam. The second one was composed of a layer viscoeastic layer with one surface bonded to the beam, and with other being constrained by nine piezoelectric actuators connected in parallel. A control law based on the sign of the angular velocity of the cantilever beam was implemented to control the beam first mode of vibration. The piezoelectric sensor output was digitally differentiated to obtain the transverse linear velocity, and its sign was used in the control algorith. Two dampers provided the system a damping increase of a factor of four for the first damper and three for the second damper. Both dampers were found to work well at low levels of vibration, suggesting that they can be used effectively to prevent resonant vibrations in flexible structure from initiating and building up.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.113-113
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• 2003