• 전자공학회논문지
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• 제51권6호
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• pp.78-86
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• 2014

본 논문에서는 질량-스프링 구조를 이용한 새로운 광세기 기반 광섬유 진동센서를 제안하고 시뮬레이션과 부분 실험을 통하여 그 실현 가능성을 제시한다. 제안한 광세기 기반 광섬유 진동센서는 네 개의 구불구불하게 휘어지는 스프링과 질량체 안의 사각형 개구면(aperture)으로 구성된 질량-스프링 구조를 가진다. 광시준기(optical collimator)는 질량체 안의 사각형 개구면의 변위에 의해서 변조되는 광을 넓히는 데 이용된다. 제안한 광섬유 진동센서를 광학적인 면과 기계적인 면에서 해석하고 설계한다. 기계적인 부분의 설계는 이론적인 해석, 수학적인 모델링 및 3 차원 유한요소법 시뮬레이션을 이용한다. 기계적인 진동이 가해질 때 개구면의 상대적인 변위관계를 3차원 유한요소법 시뮬레이션을 이용하여 구하고, 개구면의 상대적인 변위에 따른 출력값을 실험을 통하여 측정한다. 이를 이용하여 진동에 따른 출력 특성을 파악한 결과 센서 민감도 $15.731{\mu}W/G$, 감지영역 ${\pm}6.087G$를 얻었다. 그리고 입력광원의 파워가 10 dB까지 변하더라도 참조광을 이용하여 0.75%의 상대오차를 보이는 매우 안정된 출력광 파워를 얻었다. 제안한 광섬유 진동센서는 간단한 구조, 저비용 및 다지점 측정 가능의 특징을 가지면서, MEMS (Micro-Electro-Mechanical System) 기술을 이용하여 소형으로 간편하게 제작할 수 있는 잠재력을 가진다.

• 한국산학기술학회논문지
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• 제17권5호
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• pp.269-274
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• 2016

본 연구는 호퍼와 같은 공정에서 필연적으로 발생하는 스케일 또는 막힘 현상을 방지하기 위해 적용할 수 있는 저주파 전자해머 구동 시스템의 개발에 관한 것이다. 전자기계식 hammering 구동 방식은 진동과 충격량을 동시에 발생시키는 방식으로, 본 논문에서는 전자해머의 특성을 고찰하기 위하여 전자해머에 장착된 직/병렬 스프링 상수 해석을 하였고 발생에너지는 E코어에 부착된 스프링 상수가 모두 같을 경우에 계산된 등가 스프링 상수와 E코어와 I코어 사이의 동작 변위의 곱으로 계산할 수 있음을 보였다. 또한 전자해머의 충격량을 최대화하기 위하여 맥동파 구동 알고리즘을 적용하였으며, 이 알고리즘은 논리 AND 연산과 마이크로 콘트롤러(atmega128)의 타이머 인터럽트와 PWM 기능을 사용하여 구현하였다. 전자해머의 구동회로는 IGBT로 구성된 H-브리지 방식으로 설계하였고, 가속도계 측정법으로 개발한 전자 해머 시스템의 성능을 검증하였다. 실험 결과 제안한 시스템이 기계적 에너지를 양호하게 발생시킬 수 있으며, 호퍼와 같은 공정에 적용할 수 있음을 보였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.723-726
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• 2002

In the recent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. The dynamic characteristic analysis of SMA is necessary for actuator application and many common researches report the material characteristics of SMA sufficiently. However, the research of dynamic characteristics is very deficient. In this paper, the helical spring is fabricated with NiTi SMA wire of high resistivity The farce, response speed, temperature, and displacement are measured by digital force gauge, infrared thermometer, and laser displacement sensor so that the dynamic characteristics of this SMA actuator is analyzed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1179-1181
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• 1992

A discrete Pl controller is implemented easily using a micro-processor, and it can be confirmed to a adaption of a system and real time processing. In this paper, a speed controller by discrete Pl control using a IBM PC/AT(12MHz) as a micro-processor is implemented and applied to a DC servo motor. In designing the discrite Pl controller, a sampling time and a speed is accepted from key-board, and is processed the control coefficient automatically, and than calculate the gain. Therefore the speed of a DC servo motor is obtained and controlled regulaly. The designed and manufactured discrete Pl control system is experimented. The result shows the good response at the 60 RPM to 250 RPM on the load using the load-spring. The speed error is under 1% on the steady load, but nearly 2-3% on the transient load.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1730-1733
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• 2007

As semiconductor and MEMS devices become smaller, testing process during their production should follow such a high density trend. A circuit inspection tool "probe card" makes contact with electrode pads of the device under test (DUT). Nowadays, electrode pads are irregularly arranged and have height difference. In order to absorb variations in the heights of electrode pads and to generate contact loads, contact probes must have some levels of mechanical spring properties. Contact probes must also yield a force to break the surface native oxide layer or contamination layer on the electrodes to make electric contact. In this research, new vertical micro contact probe with bellows shape is developed to overcome shortage of prior work. Especially, novel bellows shape is used to reduce stress concentration in this design and stopper is used to change the stiffness of micro contact probe. Variable stiffness can be one solution to overcome the height difference of electrode pads.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.264-266
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• 2005

Recently, on-line diagnosis methods through wired and wireless networks are widely adopted in the diagnosis of industrial Electric Facilities, such as generators, transformers and motors. Also smart sensors which includes sensors, signal conditioning circuits and micro-controller in one board are widely studied in the field of condition monitoring. This paper suggests an self-powered system suitable for condition-monitoring smart sensors, which uses parasitic vibrations of the facilities as energy source. First, vibration-driven noise patterns of the electric facilities are presented. And then, an electromagnetic generator which uses mechanical mass-spring vibration resonance are suggested and designed. Finally energy consumption of the presented smart sensor, which consists of MEMS vibration sensors, signal conditioning circuits, a low-power consumption micro-controller, and a ZIGBEE wireless tranceiver, are presented. The usefulness and limits of the presented electromagnetic generators in the field of electric facility monitoring are also suggested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1051-1054
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• 2003

For micro-weighing, null balance method is widely used in the precision industrial fields, such as biomedicine, semiconductor, chemistry and so on. In order to obtain high resolution and large measurement range simultaneously, the mechanism should be analyzed and optimized. However, large measurement error can be generated according to the mass loading position and this error is called as a corner loading error. The corner loading error is caused by the parallelism error of a Roberval mechanism used to minimize it. The corner loading error is one of the most dominant error sources that should be removed. It is possible to design that the mechanism has no corner loading error theoretically, but the mechanism of the micro weighing device is very difficult to be realized as original design due to assembling and manufacturing error. For the required specification of the device, the precise manufacturing technique under a few $\mu\textrm{m}$ is required for the realization of the design. In this paper, the effects of the parallelism error are analyzed by using Lagrange method and verified by experiment. Also, the compensation mechanism is proposed and the corner loading error is reduced by restoring tile parallelism.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1577-1580
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• 2003

In the recent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. The dynamic characteristic analysis of SMA is necessary for actuator application and many common researches report the material characteristics of SMA sufficiently. However, the research on dynamic characteristics is very deficient. In this paper, the helical spring are fabricated with NiTi SMA wire of high resistivity. The force, response speed, temperature, and displacement are measured by digital force gauge, infrared thermometer, and laser displacement sensor so that the dynamic characteristics of this SMA is analyzed. Also, bidirectional actuator was fabricated and experimented for its performance.

• 한국정밀공학회지
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• 제22권10호
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• pp.195-201
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• 2005

A laterally driven electromagnetic microactuator (LaDEM) is presented, and a micro-optical switch is designed and fabricated as a possible application. LaDEM provides parallel actuation of the microactuator to the silicon substrate surface (in-plane mode) by the Lorentz force. Poly-silicon-on-insulator (Poly-SOI) wafers and a reactive ion etching (RIE) process were used to fabricate high-aspect-ratio vertical microstructures, which allowed the equipment of a vertical micro mirror. A fabricated arch-shaped leaf spring has a thickness of $1.8{\mu}m$, width of $16{\mu}m$, and length of $800{\mu}m$. The resistance of the fabricated structure fer the optical switch was approximately 5$\Omega$. The deflection of the leaf springs increases linearly up to about 400 mA and then it demonstrates a buckling behavior around the current value. Owing to this nonlinear phenomenon, a large displacement of $60{\mu}m$ could be measured at 566 mA. The displacement-load relation and some dynamic characteristics are analyzed using the finite element simulations.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.97-101
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• 2005

High strength concretes utilizing EVA with micro particles were prepared by varying polymer/binder mass ratio and curing conditions with a constant water/binder mass ratio of 0.3. The EVA modified concretes on the compressive and flexural strength, microstructure, ultrapulse modulus in curing condition(dry and water curing) were studied. Also, scanning electron microscope analysis(SEM) was performed to reveal the presence of polymer film and cement hydrates in the concrete. The compressive strength of the EVA modified concretes cured at water conditions ere higher than that of the EVA modified concretes cured at dry conditions. But, the flexural strength of the specimens cured at dry conditions were higher than that of the specimens cured at water conditions. Due to the interaction of the cement hydrates and polymer film, an interpenetrating network originated in which the aggregates were embedded. The curing of the polymer modified concrete involves two step of cement hydrates and polymer modification, and cement hydrates was promoted in water conditions and polymer film formation take place when water evaporates and was thereby was favored in dry conditions. By SEM analysis, influences of polymer modification was strengthening of the transition zone between the aggregate and the paste, and the porosity of transition zone decreases. By spring analysis, it could known that polymer film affects in porosity decrease and strengthening of transition zone.