• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.171-173
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• 2003

기존의 선형 이송 시스템은 구동원으로 서보모터를 사용하고 있다. 서보 모터의 회전 운동을 직선운동으로 변환하기 위해서는 기계적인 동력전달 장치가 필요하며, 이는 위치 오차의 발생이나 주기적인 시스템의 유지보수의 필요성 등의 문제점을 야기한다. 본 논문에서는 단위 체적당 추력비가 기존의 모터에 비해 우수한 횡축형 선형전동기를 이용하여 LCD 공정에 사용되는 indexer 시스템의 선형 추진부에 적용하는 연구를 수행하였다. 실험결과 횡축형 선형전동기는 가속능력 최대 속도 및 위치결정 정밀도 등에서 indexer 시스템에 적용하기에 적합한 것을 검증하였다.

• 전자공학회논문지 IE
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• v.46 no.4
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• pp.49-56
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• 2009

In this paper, stabilization inverse optimal control for nonlinear systems with structural uncertainty is considered. Based on the control Lyapunov function, a theorem for the globally asymptotic stability is presented. From this a less conservative condition for the inverse optimal control is derived. The result is used to design an inverse optimal controller for a class of nonlinear systems, that improves and extends the existing results. The class of nonlinear system considered is also enlarger. The simulation results show the effectiveness of the method.

• Journal of Korean Society of Steel Construction
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• v.18 no.3
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• pp.361-371
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• 2006

In recent years, to overcome drawbacks related to the aplicati on of classical structural optimization algorithms, various drift design methods based on factores of member displacement participation factors have been developed to size members if they satisfy stiffness criteria. In particular, a resizing algorithm based on dynamic displacement participation factors from the response spectrum analysis has been applied in the drift design of steel structures subjec ted to seismic lateral forces. In this aproach, active members are selected for displacement control based on the displacement participation fa ve members may be taken out and added to the active members for the drift control. The resizing algorithm can be practically and effectively applied to drift design of high-rise buildings however, the inelastic behavior o f the resizing algorithm has not ben evaluated yet. To develop the resizing algorithm considering the performance of nonlinearity as well a s elastic stifness, the evaluation model of resizing algorithm s is developed and aplied to the examples of moment-resisting steel frame, which is one of the simplest structural systems. The inelastic behavior of moment-resisting steel frame designed by the resizing algorithm is also discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.5
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• pp.375-380
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• 2007

The nonlinear aerodynamic analysis of wing with control surface is performed using the frequency-domain panel method. To take into consideration the nonlinear aerodynamic characteristics of wing an iterative decambering approach is introduced. The iterative decambering approach uses the known aerodynamic characteristics of airfoil to calculate the aerodynamic characteristics of wing. The multi-dimensional Newton iteration is used to account for the coupling between the different sections of wing. The present method is verified by showing that it produces results that are in good agreement with experiments. The present method will be useful for the analysis of aircraft in the conceptual design because the present method can calculate promptly the nonlinear aerodynamic characteristics of wing with a few computing resources.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.92-93
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• 2002

선형 및 비선형 광학 특성이 뛰어난 것으로 잘 알려진 LiNbO$_3$ (LN) 및 $K_3$Li$_2$Nb$_{5}$O$_{15}$ (KLN) 단결정을 원료분말의 조성 등과 같은 결정성장 조건을 달리하여 Czochralski 방법으로 성장시켰다. LN과 KLN 단결정의 경우 성장온도가 고온이기 때문에 Li, K 이온의 휘발에 의해 성장된 결정의 조성은 원료분말의 조성과 다르다. 따라서 성장된 단결정의 조성을 분석하는 것은 응용을 위해 매우 중요한 일이다. (중략)

• Journal of KSNVE
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• v.7 no.1
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• pp.20-29
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• 1997

내부공진은 2자유도계 이상의 다양한 비선형 시스템에 존재할 수 있으며 모드 사이의 진동에너지의 교환의 원인이 된다. 위에서 설명한 흡진기의 경우처럼 그 시스템의 동작에 필수적인 요소가 되기도 하며 직사각형 평판의 경우처럼 선형이론 으로는 예측불가능한 진폭변조된 진동을 유발하기도 한다. 이론적인 해석의 결과 다양한 분기와 여러가지 형태의 해를 가지며, 특히 주기적 정상해와 혼돈적인 해를 갖는 것이 밝혀졌다. 이러한 주기적 정상해는 구조물에 따라 여러 가지 형태로 나타 나며 평판의 경우는 진폭변조된 움직이는 파형으로, 본문에서는 언급하지 않았지만 현의 경우는 타원의 퀘적의 크기와 주축의 방향의 변화로 나타난다. 이러한 다양한 해들은 구조물의 종류와 형상에 따라 다른 형태로 나타나며 향후 연구의 대상이라 생각되어진다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.5
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• pp.623-628
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• 2007

The accurate peak response estimation of a seismically excited structure with frictional damping system(FDS) is very difficult since the structure with FDS shows nonlinear behavior dependent on the structural period, loading characteristics, and relative magnitude between the frictional force and the excitation load. Previous studies have estimated that by replacing a nonlinear system with an equivalent linear one or by employing the response spectrum obtained based on nonlinear time history and statistical analysis. In the case that an earthquake load is defined with probabilistic characteristics, the corresponding response of the structure with FDS has probabilistic distribution. In this study, nonlinear time history analyses were performed for the structure with FDS subjected to artificial earthquake loads generated using Kanai-Tajimi filter. An equation for the probability density function (PDF) of the displacement response is proposed by adapting the PDF of the normal distribution. Finally, coefficients of the proposed PDF are obtained by regression analysis of the statistical distribution of the time history responses. Finally the correlation between PDFs and statistical response distribution is presented.

• Journal of Navigation and Port Research
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• v.31 no.1 s.117
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• pp.55-64
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• 2007

In general mechanical servo systems, friction deteriorates the performance of controllers by its nonlinear characteristics. Especially, friction phenomenon causes steady-state tracking errors and limit cycles in position and velocity control systems, even though gains of controllers are tuned well in linear system model. Even if sensor is used higher accuracy level, it is difficult to improve tracking performance of the position to the same level with a general control method such as PID type. Therefore, many friction models were proposed and compensation methods have been researched actively. In this paper, we consider that the variation of mover's mass is various by loading and unloading. The normal force variation occurs by it and other parameters. Therefore, the proposed control system is composed of main position controller and a friction compensator. A parameter estimator for a nonlinear friction model is designed by adaptive control law and adaptive backstepping control method.

• Journal of Korean Association for Spatial Structures
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• v.6 no.1 s.19
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• pp.75-82
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• 2006

The single layer latticed dome is very sensitive on the slenderness ratio and half open angle of the elements, load condition, and the connection type because it is organized by a lot of thin elements, so we have to use the geometrically nonlinear buckling load when the buckling of the structures is analyzed. But, it is very difficult to design the single layer latticed domes considered all renditions. Therefore the purpose of this paper is to propose the appropriate design method of the single layer latticed dome considered the geometrically nonlinear buckling load in base of the linear buckling load by the eigenvalue analysis.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.11
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• pp.1277-1284
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• 2015

In this paper, 1-axis tracking mechanism of solar-cell panel, which is able to rotate from -90 degree to +90 degree for maintaining always perpendicular between solar-cell panel and sun, was analyzed. This paper propose the non-linear shaped guidance and analyze mathematical formulation of non-linear shape. This analysis shows that it is able to identify the non-linear shaped guidance. Especially, even though the length of rotating link have changed, the non-linear shaped guidance could be confirm with proper size. As effectiveness of this result, 10% efficiency rising is estimated compared to the conventional 1-axis tracking mechanism and also optimal non-linear shaped guidance can be suggested for various size of solar-cell panel. Therefore the flexible mass-production is possible for various size of non-linear shaped guidance.