• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.201-208
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• 2006

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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.927-928
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• 2009

• Journal of the Microelectronics and Packaging Society
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• v.16 no.1
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• pp.39-43
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• 2009

In order to develop piezoelectric inverter module for CCFL driving, Rosen-type multilayer piezoelectric transformer was fabricated. The output power and efficiency of mutilayer piezoelectric transformer according to the variation inner electrode layer were investigated. Mutilayer piezoelectric transformer was fabricated conventional mutilayer ceramic method using PZT base ceramics. Also, piezoelectric inverter module was adopted driving circuit with half-bridge type. The piezoelectric inverter module was set up with input voltage 12.5 V, switching frequency 104.3 KHz. The results showed the value of step-up ratio 100, efficiency 87% at load resistance of $100k{\Omega}$.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.421-426
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• 2005

Optimal design of serial connected PZT driven micro compressor was investigated. Modeling equations were derived using energy equation and mass conservation equation. The results show that mass flow rate was increased as number of connected micro compresses is increased. As pressure difference between suction port and discharge port in compressor group is increased, connected compressors have much more mass flow rate than single compressor. Mass flow rate is also increased as driving frequency is increased. And optimal design scale is suggested for highest efficiency or highest mass flow rate.

• Journal of IKEEE
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• v.24 no.3
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• pp.803-813
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• 2020

This paper presents a high efficiency resonant flyback converter using a single-chip microcontroller. The proposed converter primary performs the resonant switching by applying the asymmetrical pulse-width modulation (APWM) to the half-bridge power topology. And the converter secondary uses the diode flyback rectifier as its power topology and operates with the zero current switching (ZCS). Thus the proposed converter achieves high efficiency. The total structure of proposed converter is very simple because it uses a single-chip microcontroller and bootstrap circuit for its control and drive, respectively. First, this paper describes the converter operation according to each operation mode and shows its steady-state analysis. And the software control algorithm and drive circuits operating the proposed converter are explained. Then, the operation characteristics of proposed converter are shown through the experimental results of an implemented prototype based on each explanation.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.8
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• pp.543-548
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• 2003

In this paper, we have proposed and fabricated a two-axis rotational micro-mirror with large tilt angle. Such a micro-mirror is a key element for N$\times$N high capacity optical cross-connect switches. The micro-mirror is required to have large tilt angle to increase the capacity of the cross-connect switches. For larger micro-mirror tilt angle between the grounded mirror plate and the bottom electrode is to be large enough to provide space for the tilting of the mirror. For our proposed structure, the gap was produced in such a way that the grounded mirror plate and the bottom electrode were made separately in different substrates by using the bulk micromachining technology, and combined later by employing self-align technique. As a result, a large tilt angle has been achieved without using additional actuators. The measured tilt angles were as large as $\pm$5.5$^{\circ}$ and $\pm$8.4$^{\circ}$ in the x and y direction respectively, and the pull-in voltages for the two directions were 380 V and 275 V respectively. Finally the fabricated mirror was successfully utilized to steer the optical beam. To our knowledge, our micro-mirror has the best performance among the micro-mirrors reported internationally so far.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.235-236
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• 2016

본 연구에서는 고 성능 마이크로프로세서를 이용한 공기조형물의 관절 구동과 센서의 환경 인식에 능동적으로 대처할 수 있는 시스템을 연구하였다. 객체기반의 공기조형물용 모션제어 시스템은 단일 제어기로의 역할보다 시스템 구성요소로서의 역할이 매우 중요해지므로 시스템 전체의 제어기로 확장시켜 사용하는 방향으로 전환되어야 한다. 본 연구에서는 시스템의 구동과 환경에 능동적으로 대처할 수 있는 객체기반 공기조형물을 연구하였다. 모터제어 방법에 있어 CAN(Controller Area Network) 네트워크를 방식을 통하여 제어를 수행하는 분산제어방식으로 수행하였다. CAN방식은 모션제어 시스템에 도입하여 주 제어기가 하위 제어기에 네트워크를 통하여 명령을 내리며 하위제어기는 주어진 위치 및 속도명령에 대하여 분산적으로 제어를 수행하였다. 따라서 CAN방식을 사용하여 각 제어기의 독립성과 처리속도를 증대시키고 공기조형물의 기능별 확장이 용이하도록 구성하였다. 제어기의 환경은 시스템을 총체적으로 조화롭게 제어할 수 있는 시스템으로의 역할이 중요시되어 이에 맞도록 설계방안을 연구하였다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.2
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• pp.74-79
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• 1997

본 논문에서는 8비트 마이크로 컨트롤러를 이용한 제어기를 여러 개를 다중 접속하여 구성한 분산형 방재 시스템을 제시하였다. 방재 시스템은 워크스테이션 또는 PC등의 호스트 시스템에 의하여 제어되며 호스트 시스템에 다수의 소형 제어기가 공통 통신 선에 의하여 연결된다. 각 제어기는 서로 다른 주소를 가지며 호스트 컴퓨터는 명령어 패킷에 특정 제어기의 주소를 첫 바이트로 실어 공통 통신 선으로 전송한다. 명령어 패킷의 주소에 해당하는 제어기는 명령어 패킷을 수신하여 입력상태를 호스트로 전송하고나 명령어에 따라 필요한 구동 출력을 발생하고 호스트로 자신의 주소를 포함한 응답 패킷을 전송한다. 서로 다른 주소를 이용하여 열 개의 제어기를 공통 통신 선으로 다중 접속함으로 분산형 방재 시스템을 구현하였다. 현재 방재 시스템의 동향은 분산형 방식으로 옮겨가는 추세이며 선로의 절약, 설치, 중설의 간편함과 함께 빌딩 자동화 시스템과 쉽게 연동하여 운영될 수 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.244-247
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• 2002

The performance of the precision micro-positioning 4-dof stage is presented. The compact design utilizes the monolithic mechanism to achieve the translation in the Z axis and rotation in the $\theta$ z, $\theta$ x and $\theta$ y axes with high stiffness and high damping. Hysteresis, nonlinearity, and drift of the piezoelectric effects are improved by incorporating the sensors in a feedback control. Experiments demonstrate that the micro-positioning stage is capable of 2nm resolution over the travel range of 25$\mu\textrm$ m in the Z axis, 0.0l7 $\mu\textrm$ rad resolution over the 170$\mu\textrm$ rad in the $\theta$ z and 0.011 $\mu\textrm$ rad resolution over the $\mu\textrm$ rad in the $\theta$ x and $\theta$ y axes. The cross-axis interferences among the axes are at a noise range. This stage is available for positioning error compensation of the XY stage with large stroke.