• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.93-99
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• 2012

This paper presents an optimal design of magnetorheological (MR) fluid based mount (MR mount in short) which can be applicable to vibration control of diesel engine of ship. In this work, a mixed - mode including squeeze mode, flow mode and shear mode is proposed and designed. In order to determine actuating damping force of MR mount required for efficient vibration control, excitation force from diesel engine is analyzed. In this analysis, a model of V-type engine is considered and the relationship between velocity and pressure of gas in torque of the piston is derived. Subsequently, by integrating the field-dependent rheological properties of commercially available MR fluid with the excitation force an appropriate size of MR mount is designed. In addition, in order to achieve maximum actuating force with geometric constraints design optimization is undertaken using ANSYS software. Through the magnetic density analysis, optimal design parameters such as bottom gap and radius of coil are determined.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.594-597
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• 2011

본 논문에서는 태양광 추적기에 구동하기 위하여 적용된 기존 기계식 방식의 단점을 극복하기 위하여 전자력을 사용하였다. 영구자석과 전자석의 배치와 형상에 따라서 자속밀도를 분석하고 두 개의 자석이 맞대어 있을 때 척력과 인력을 이용하여 태양광 추적기의 회전 매카니즘에 적용하였다.

• Bulletin of the Korean Space Science Society
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• 2006.10a
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• pp.136-136
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• 2006

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.712-713
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• 2010

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.706-707
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• 2010

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.6
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• pp.573-584
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• 2014

In this study, the variations of cutter acting forces depending on cutting conditions were examined to obtain basic data for roadheader cutting head design. The linear cutting tests were performed in the condition of different attack angles, penetration depths, cutter spacings by using a slim conical pick for the light cutting condition. Cutter acting forces were measured by 3-directional load cell under different test conditions, and the analysis for cutting performance were carried out after calculating average values of the measured results. It is confirmed that the optimal cutting condition for the mortar specimen is the 50 degree attack angle, the cutter spacing of 12 mm, the cutting depth of 9 mm which are obtained from the analysis results. In addition, 50 degree attack angle is more effective than 45 degree attack angle to design optimal specifications of cutting head.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.7-10
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• 2004

KOMPSAT-2 needs fine accuracy attitude control when it is operated in Science mode. Reaction Wheel is a necessary part of fine controlling the attitude of satellite. The reaction Wheel Assembly(RWA) is a device which provides reaction torque for attitude-control of spacecraft. It consists of an electric motor, a rotating flywheel, motor control device electrics, commutation electronics and associated power converters. This document identifies what activities to be carried out to integrate the RW#1 for ETB tests.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.286.2-286.2
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• 2013

기존의 이온성 고분자-금속 복합체(IPMC)는 백금(Pt)전극을 이온성 전기활성 고분자(Ionic electroactive polymer)인 나피온에 무전해 도금으로 만들어졌다. 본 연구는 백금전극을 그래핀으로 대체하여 투명 이온성 고분자-그래핀 복합체(IPGC)를 제작하였다. 그래핀은 근적외선 화학기상증착법(NIR-CVD)으로 전이금속 (Cu, Ni) 위에 탄화수소 가스(CH4)를 이용하여 성장하였다. 전이 금속위에 성장된 그래핀을 나피온 양쪽면에 van der Waals 결합력을 이용하는 습식 전이공정으로 전극을 형성하였다. IPGC는 면 저항(4-point probe), 투과도(UV/Vis spectrometer) 및 라만 분광법(Micro Raman spectroscopy)의 측정으로 그래핀 전극의 특성평가를 하였고, 전계방사 주사전자현미경(Field Emisson Scanning Electron Microscope; FE-SEM)을 사용하여 IPGC의 구조적 특성을 확인하였다. 제작된 IPGC의 성능은 백금전극을 이용한 IPMC의 변위(displacement), 힘(force), 작동 주파수(Operating frequency) 분석을 통해 비교 평가하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.180-185
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• 2009

Actuator-induced disturbance is one of the crucial factors of spacecraft attitude pointing and stability in fine attitude control problems. The control moment gyros (CMGs) are known as very attractive actuators from the point of high power and low weight. In order to develop a CMG as an actuator for fine controls, CMG-induced disturbances should be analyzed. Therefore, this paper aims to develop an analytic model and predict the effect of disturbances of CMGs by assuming static and dynamic imbalances. The proposed model is induced by the Lagrangian method on the basis of the small signal assumption. In this research, mechanical system of the CMG is designed and the main components of CMG are producted.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1119-1127
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• 2010

In this paper, the design and nonlinear simulation of a multistable electromagnetic microactuator, which provides four stable equilibrium positions within its operating range, have been discussed. Quadstable actuator motion has been made possible by using both X- and Y-directional bistable structures with snapping curved beams. Two pairs of the curved beams are attached to an inner frame in both X- and Y-directions to realize independent bistable behavior in each direction. For the actuation of the actuator at the micrometer scale, an electromagnetic actuation method in which Lorentz force is taken into consideration was used. By using this method, micrometer-stroke quadstability in a plane parallel to a substrate was possible. The feasibility of designing an actuator that can realize quadstable motion by using the electromagnetic actuation method has been thoroughly clarified by performing nonlinear static and dynamic analyses and electrothermal coupled-field analysis of the multistable microactuator.