• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.130-137
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• 2005

LCD needs a backlight that is a light source as a photodetector that has a light modulation function and CCFL is used usually. Inverter that composes using existent winding transformer operates multi lamps, however, this efficiency falls by losses of core or winding and volume or weight increases or there is danger of fire by overheating. In order to solve these problems, a multi lamp driving Inverter using PT is composed according to the design guideline in this paper. We conformed whether the multi lamp drive method using EEFL that a current burden is less in applicable to piezoelectric inverter, and used the method that connect two piezoelectric transformers by parallel to an inverter.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.575-576
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• 2008

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.754-758
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• 2001

A new kind of piezoelectric actuation structure named double amplified multilayer actuator is proposed. Double amplified multilayer actuator combines both dimentional and flextensional amplification concepts. As a result the displacement of the actuator can be more than one hundred times larger than the displacement of multilayer actuator and can be used in in-pipe locomation robot such as an endoscope actuator. This paper studied the dependence of displacement on actuator parameters theoretically and experimentally.

• Composites Research
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• v.27 no.2
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• pp.47-51
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• 2014

The purpose of the present study is to develop lightweight and simple smart actuators in order to replace conventional hydraulic/pneumatic actuators, and to apply the developed actuators to the actuation systems of a small unmanned air vehicle. This research describes the procedures of design, manufacturing of the piezo-composite actuator, and the performance evaluation. From the test results of the developed devices, we found the possibility of piezo-composite actuator could be used as a control surface of a small UAV system. We have designed and manufactured two kinds of piezo-composite actuators, unimorph actuator and bimorph actuator. The manufactured actuators were evaluated through the performance testes. It was found that the bimorph type actuator showed more linear angle change for the same excitation voltage variation than unimorph type. It is expected that piezo-composite actuator has a possibility to be used not only as a control surface of small unmanned flying vehicle but also as a control surface actuator of a guided missile fin through the miniaturization of power supply and control system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.450-453
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• 1995

The beam rotating actuator, which can be utilized to improve the data transfer rate for the optical disk systems, has been developed. It can employ a newly developed laser beam rotating actuator for putting multi-beam spots on more than one track on the optical disk simultaneously. Therefore, It has to maintain up to .+-.0.01 .deg. resolution and high bandwidth performance. In this these, the Dove prism is used for the beam rotating actuator based on bimorph piezo material. The performance of the beam rotating actuator is verified since the dynamics ferquency performance is measured using the dynamic analyzer and the attached stain gage sensor. the beam rotating angle performance is also examined since the long range beam reflection character is utilized.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.437-441
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• 1995

In this paper, the ultra precision positioning system for servo motor and piezo actuator using dual servo loop control has been developed. For positioning system having long distance with ultra precision, the combination of global stage and micro stage is required. Servo moter and ball screw are used as a master stage and piezo acuator as a fine stage. By using this system, an positional precision witin .+-. 30nm has been achieved at dual servo loop control. When using micro stage, an positional precision within .+-. 10nm has been achieved. This result can be applied to develop semiconductor equipment such as wafer stepper.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.324-330
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• 2012

In this paper, we presents a robust control system design for compensating hysteresis of a piezoelectric actuator-based actuation unit. First, the dynamics between the input voltage and the output displacement of the actuation unit are unravelled via a non-parametric system identification method. From the dynamic characteristics of those experimental transfer functions, a parametric model is then derived, whose dynamics match those of the non-parametric ones under various conditions on input voltages. A robust controller is constructed on the basis of this parametric model in order not only to effectively compensate the hysteresis of the actuation unit but also to guarantee the robust stability. Extensive experiments show that the proposed robust control system successfully mitigate the effect of the hysteresis and improve the tracking capability of the actuation unit.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.505-507
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• 2004

This paper attempts to compensate the nonlinearity between the input voltage and the output displacement of the piezoelectric stack in dynamic actuation by the following two ways. Firstly, the charge steering by circuit configuration reduces the hysteresis of piezoelectric actuator remarkably. However, it makes the ripple in positioning due to the phase lag and noise induced from the elements of the long closed loop. Secondly, the feedforward control by neural network compensates the hysteresis of the piezoelectric actuators effectively with the appropriate selection of the input variables for the training. The improvement of the dynamic performance of the piezoelectric actuators by the developed linearization technique is verified by experiments.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.5
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• pp.154-159
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• 2000

A multi-beam optical disk drive is presented as a method for improving the effective data transfer rate by increasing the beam spot number formed on an optical disk. The beam rotating actuator is necessary for putting multi-beam on more than one track. The beam rotating actuator is made up of piezoelectric material, high stiffness wire hinge and dove prism. The actuator has good frequency response above 1KHz and suitable operational range. The dynamic equation for the actuator is derived.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.301-301
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• 2010

현재 전 세계는 앞으로 사용 될 대체 에너지에 많은 관심 가지고 있다. 지금 사용하고 있는 에너지 연료는 한정되어 있기 때문에 대체에너지에 대한 연구가 활발히 진행 되고 있다. 그 중 압전체를 이용한 에너지 하베스팅은 많은 주목을 받고 있다. 주변 환경에서 필요한 에너지를 끌어 쓸 수 있는 대표적인 청정에너지 시스템 중 하나이기 때문이다. 최근 전원 공급원으로써 에너지 수확 시스템은 현 사회에 사용되고 있는 배터리로 전원을 사용하는 제품들을 소용량과 저전압 분야에서의 에너지 수확의 원리를 이용하여 전기전자제품의 사용시간 연장 및 응용분야 확대를 시도하는 연구가 활발히 수행되고 있다. 압전세라믹스를 이용한 에너지 하베스팅은 진동에너지를 전기에너지로 변환하는 것으로서 압전 특성이 높아야 한다. 일반적으로 압전 세라믹스는 PbO 성분이 들어가므로 환경적 오염 뿐만 아니라 인체에도 영향이 좋지 않으므로 많은 나라에서 이러한 성분을 제한하고 점차적으로 줄어들고 있는 시점에서 PbO를 사용하지 않고 Lead-Free 세라믹를 사용한 연구가 진행되고 있다. 이 논문에서는 일반적인 소결 방법을 이용하여 (Na,K)NbO3 세라믹에 CeO2를 첨가한 압전 세라믹을 제작하였다. 제작된 압전 세라믹스로 에너지 하베스팅 소자를 제작하고, 이 소자로 수확된 에너지로 DC-DC Converter 응용 특성에 대하서 연구하였다. 압전 세라믹스의 좋은 압전 특성을 출력하기 위하여 캔틸레버의 고유 진동수가 진동원의 주파수와 일치하는 공진을 일으켜야 한다. 따라서 구동회로는 주파수원을 찾아 설계하였고, 압전 세라믹스의 진동은 가진기를 이용하여 구동실험을 하였다. 지금까지 나와있던 에너지 하베스팅 회로와 비교하여 그 특성을 분석하고, 시뮬레이션 및 실험을 통하여 검증하였다.