• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.202-207
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• 2002

This paper deals with a novel shunted actuator, which has a capability to suppress multi-mode vibration amplitudes by using a pair of piezoceramic patches. In order to describe the characteristic behaviors of shunted dampers connected with a series and a parallel resistor-negative capacitive branch circuit, the stiffness ratio and loss factor with respect to the non-dimensional frequency are considered. To obtain a guideline model of a piezo/beam system connected with a series and a parallel resistor-negative capacitor branch circuit, the governing equations of motion is derived through Hamiltons principle and a piezo sensor equation as well as a shunt damping matrix is developed. The theoretical analysis shows that the shunted actuator developed in this study can significantly reduce multiple-mode vibration amplitudes simultaneously over the whole structural frequency range.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.446-452
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• 2005

Recently, there are many studies for the micro-machining using Piezo actuator. However, because of its step by step motion, it is nearly impossible to increase the machining accuracy for a circular path. To increase the accuracy, it is well known that it is necessary the finer and synchronous movement for x-y axes. Therefore, this paper proposes a voltage control for finer movement of the actuator, and realizes a synchronous control for the x-y axes. The experimental results show that the machining accuracy is remarkably improved.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.543-550
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• 2005

Recently, there are many studies for the micro-machining using Piezo actuator. However, because of its step by step motion, it is nearly impossible to increase the machining accuracy for a circular path. To increase the accuracy, it is well known that it is necessary the finer and synchronous movement for x-y axes. Therefore, this paper proposes an adaptive control for finer movement of the actuator, and realizes a synchronous control for the x-y axes. The experimental results show that the machining accuracy is remarkably improved.

• Composites Research
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• 제30권1호
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• pp.15-20
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• 2017

본 논문에서는 지능 구조물 작동기의 성능 향상을 위해 압전 단결정을 적용한 압전 복합재료 작동기 LIPCA-S2를 설계, 제작하고 성능을 측정하였다. 외팔보 형태로 고정된 LIPCA-S2의 끝단 변위를 예측하기 위하여 공급 전압에 대한 압전 재료 작동층의 변형을 기반으로 곡률 변화 예측 모델을 적용하였으며, 실제 작동기의 성능을 측정하여 두 결과를 비교하였다. 외팔보 상태의 LIPCA-S2의 끝단 처짐에 대한 결과를 비교하였을 때, 예측 결과가 측정 결과에 비하여 4배 정도 크게 예측되었음을 확인하였다. 각 결과의 차이는 LIPCA-S2 내부에 삽입된 압전 단결정에 작용하는 압축 응력에 대하여 압전 단결정 특성이 영향을 미치는 것이라 가정하여, LIPCA-S2를 제작하는 과정에서 발생된 잔류 응력과, 작동층에 전압을 가하며 작동기를 구동했을 때 발생하는 응력 변화를 고전 적층 이론을 통해 계산하였다. 박판 압전 단결정에 평면 방향으로 압축 응력이 변할 때, 압전 변형상수의 변화와 탄성계수의 변화를 측정하였고, 이러한 특성 변화를 고려한 새로운 예측 모델을 활용한 예측 결과는 실제 측정값에 근접함을 알 수 있었다.

• Composites Research
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• 제16권2호
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• pp.41-47
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• 2003

본 논문은 몇 가지 종류의 압전 복합재료 작동기 LIPCA의 성능 시험 및 비교에 관한 것이다. LIPCA는 압전 세라믹을 중심으로 상층부는 탄성계수가 크면서 열팽창계수가 낮은 섬유강화 복합재료 층이, 하층부는 탄성계수가 작으면서 열팽창계수가 큰 섬유강화 복합재료 층으로 구성되어 있다. 작동기의 성능 검증을 위해 작동 지그 및 전압 공급 장치 그치고 비접촉 레이저 센서로 이루어진 실험 시스템을 구성하였다 성능 비교시험 결과 검증실험으로부터 압전 작동기의 작동성능은 전기 작동 재료층이 중립면으로부터 멀리 벗어나게 위치하면서, 동시에 적층판의 전체 굽힘 강성을 작게 하면 극대화할 수 있다는 사실을 입증하였다.

• 전기학회논문지
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• 제62권8호
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• pp.1095-1100
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• 2013

Piezo devices have large power density and simple structure compared with conventional electrical motors. Thus they can generate larger forces than the conventional actuators with small size. Their resopnses to commands are also very fast and thus the bandwidths are very wide. Thus the piezo devices are expected to be used widely in the future for actuating devices requiring fast response and large actuating force with small size. However, the piezo actuators need high voltage with high driving current due to their large capacitive property. In this paper, proposed is a simple method to drive piezo devices using voltage inversion circuit with coli inductance. The coil inductance carries the charges in the piezo device to the opposite side, inverting the polarity of the applied voltage, thus saving the power to drive the device with AC voltages. Experiments with real circuit demonstrates that the proposed scheme can improve the energy efficiency very much.

• 한국분무공학회지
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• 제19권1호
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• pp.9-14
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• 2014

Performance of DI diesel engine with high-pressure fuel injection equipment is directly related to its emission characteristics and fuel consumption. So, the electro-hydraulic injector for the common-rail injection system should be designed to meet the precise high fuel delivery control capability. Currently, most high pressure injector in use has a needle driven by the solenoid coil energy or the piezo actuator controlled by charge-discharge of output pulse current. In this study, macroscopic spray approaching method was applied under constant volume chamber to research the performance of three different injectors : solenoid, indirect-acting piezo and direct-acting piezo type for CR direct-injection. LED back illumination for Mie scattering was applied on the liquid spray visible of direct-acting piezo injector, including hydraulic-servo type solenoid and piezo-driven injectors. As main results, we found that a direct-acting piezo injector had better a spray tip penetration than hydraulic-servo injectors in spray visualization.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.147-148
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• 2009

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.71-72
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• 2011

• 한국세라믹학회지
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• 제42권11호
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• pp.758-762
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• 2005

Gas valve for domestic use is used for flow control of LPG (Liquefied Petroleum Gas) or LNG (Liquefied Natural Gas) of which pressure is about $200\;mmH_{2}O(\fallingdotseq0.0196\;[bar])$. 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.