• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.62-71
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• 2009

In this paper, an improved drive method of piezoelectric PZT stack actuator for micro-positioning system is proposed and the performances are evaluated. This type of amplifier is based on switching technology efficiently handling the arbitrary regenerative energy from the piezoelectric actuator. The conventional voltage-feedback control method has the THD of -32dB (${\approx}2.5%$) with 100mHz sinusoidal reference, which means that the positioning performance in linearity degrades due to the hysteretic relationship between actuator voltage and the displacement. This paper proposed an improved charge-controlling method, which utilizes differential information of charge reference instead of integrating the actuator's current. The current waveform has THD under -40dBV (=1%) and the displacement waveform nearly -52dB (${\approx}0.25%$), which means that the positioning performance is very excellent. Finally, another method of the displacement feedback control has better performance than the voltage method, however there exists a limitation in performance of the system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.167-171
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• 1995

본 연구에서는 광픽업 액츄에이터의 동적특성과 관련한 주요 설계 변수를 도출하였고, 이 결과를 이용하여 초기설계를 용이하게 하는 방안을 제시하였다. 이러한 연구결과를 바탕으로 많은 시간과 노력을 들이지 않아도 주요한 설계변수만을 사용하여 초기 설계단계에서 핵심적인 부분에 대한 사양을 결정할 수 있을 것이며, 이를 바탕으로 상세 설계단계에서 보다 창의 적인 설계를 수행할 수 있을 것이다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.160-160
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• 2004

초음파 여기를 이용한 물체 이송 시스템은 최근 급속히 발달하고 있는 광산업이나 반도체 산업에서 기존의 이송 시스템의 단점을 보완하기 위해 개발되었다. 기존의 이송 시스템들은 이송공정이나 검사 공정 등에서 광소자의 표면손상이나 자기장에 의한 반도체 소자의 전자적 배열의 손상이 우려되었다. 하지만 PZT 액츄에이터로 구동되는 초음파 발생장치(Ultrasonic wave generator)에서 발생한 초음파 여기를 이용하여 물체를 이송시킬 경우 이러한 단점은 보완된다.(중략)

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.214-218
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• 2002

In recent years, precision positioning stage is demanded for some industrial fields such as semi-conductor lithography, ultra precision machining, and fabricating of nano structure. In this research, precision multi-axis positioning stage, which consists of pzt actuator, flexure, and capacitance gauge, is designed and developed. The performance of 3-axis positioning, characteristics of motion and resolution are verified.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.561-562
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.813-814
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.793-794
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• 2013

• Polymer Science and Technology
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• v.23 no.6
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• pp.615-623
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.488-491
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• 2006

In this paper, a slim type actuator is proposed rising a bimorph PZT and a circular rotor link. The bimorph contacts the circular rotor, and its displacement generates the rotational motion of the rotor. The rotor causes the linear motion of AF and zoom lens through gear and a motion guide. The proposed model enables the actuations of many lens groups for zoom module by extending the single lens model. The important design parameter is the contact force determined by the frictional coefficient and preload between the rotor and PZT bimorph. A prototype of the single actuator model is manufactured and experiments results using LDV and tachometer are compared to the theoretical and numerical predictions. Experiments show the linear bimorph actuator model meets the performance criteria of the lens actuation, and it can be applicable to various slim type actuators for AF and zoom motions in mobile cameras.

• Journal of Sensor Science and Technology
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• v.7 no.6
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• pp.446-451
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• 1998

Recently, conductive polymer is known to be direct-drive active material which can convert electrical energy directly into mechanical energy. In this paper, the polymerized thickness of polypyrrole is measured with change of polymerization conditions and the mechanical bending is analyzed for various polymerized thickness. In order to detect of mechanical bending, bending beam method using the bridge shaped sample is used. Thickness of polypyrrole is proportional to polymerization time in fixed current density. Also it shows a linear relation with the applied current except high current density. Maximum displacement appears at the thickness of $18.35{\mu}m$ which has been polymerized at $5.4{\mu}A/mm^2$ and for 120min and actuated at the frequency of 0.1Hz.