• 한국정밀공학회지
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• 제22권4호
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• pp.92-98
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• 2005

The learning control develops controllers that learn to improve their performance at executing a given task, based on experience performing this specific task. In a previous work, the authors presented an iterative precision of linear decentralized learning control based on p-integrated learning method for the vertical dynamic multiple systems. This paper develops an indirect decentralized teaming control based on adaptive control method. The original motivation of the teaming control field was loaming in robots doing repetitive tasks such as on an assembly line. This paper starts with decentralized discrete time systems, and progresses to the robot application, modeling the robot as a time varying linear system in the neighborhood of the nominal trajectory, and using the usual robot controllers that are decentralized, treating each link as if it is independent of any coupling with other links. Some techniques will show up in the numerical simulation for vertical dynamic robot. The methods of learning system are shown up for the iterative precision of each link.

• Wind and Structures
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• 제2권4호
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• pp.267-284
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• 1999

Multiple tuned mass dampers are proposed to suppress the vertical and torsional buffeting and to increase the aerodynamic stability of long-span bridges. Each damper has vertical and torsional frequencies, which are tuned to the corresponding frequencies of the structural modes to suppress the resonant effects. These proposed dampers maintain the advantage of traditional multiple mass dampers, but have the added capability of simultaneously controlling vertical and torsional buffeting responses. The aerodynamic coupling is incorporated into the formulations, allowing this model to effectively increase the critical speed of a bridge for either single-degree-of-freedom flutter or coupled flutter. The reduction of dynamic response and the increase of the critical speed through the attachment of the proposed dampers to the bridge are also discussed. Through a parametric analysis, the characteristics of the multiple tuned mass dampers are studied and the design parameters - including mass, damping, frequency bandwidth, and total number of dampers - are proposed. The results indicate that the proposed dampers effectively suppress the vertical and the torsional buffeting and increase the structural stability. Moreover, these tuned mass dampers, designed within the recommended parameters, are not only more effective but also more robust than a single TMD against wind-induced vibration.

• 한국구조물진단유지관리공학회 논문집
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• 제7권4호
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• pp.201-208
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• 2003

철근콘크리트 코어 벽체와 외부 철골골조로 구성된 복합벽체시스템은 중앙 코아 전단벽 주변의 오픈공간을 갖는다. 이와 같은 복합 벽체시스템은 연결된 벽체가 대부분의 횡하중에 저항하고 벽체저면과 커플링 보에서 대부분의 에너지를 소산할 수 있는 설계기법을 개발하는 것이 필요하다. 본 연구논문은 커플링 보의 접합방식 및 층규모를 주변수로 수직하중 및 풍하중과 지진하중을 받는 복합 벽체시스템에 대하여 전단력, 전도모멘트, 최대 횡변위, 층간변위비 및 동적특성을 규명하였다.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권4호
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• pp.375-379
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• 2013

In this paper, the magnetic coupling between an induction cooker and a metallic pot is studied for various winding topologies. Effects of the winding orientation on the power transfer capability and on the emitted magnetic field under the cooker are discussed and compared. A novel topology inspired by permanent magnet Halbach array is proposed. This consists in coupling in both horizontal and vertical directions and to create an asymmetric field in order to reduce the emission under the cooker.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.161-166
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• 2002

Recently, researches on precision machining of nato-order, especially in the field of optical components and semi-conductors have been under development very actively. A accuracy of machining and positioning in a critical issue in ultra-precision machining. This paper proposes a new positioning system which can give excellent dynamic characteristics and reduce errors in horizontal, vertical, pitching, and yawing motions. In this paper, we suggest a connecting mechanism (the couplings) to reduce motion errors such as chatter and runout while preserving the positioning accuracy. We verified the good performance in the new connecting systems with various coupling types, which we classified into the fixed type, the spring type, the aeroctatic-nozzle type, and the aeroctatic-porous type according to the way of reducing the chatter and error.

• Geomechanics and Engineering
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• 제8권6호
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• pp.845-857
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• 2015

The 3D numerical analysis is carried out to investigate the settlement behavior of flexible mat foundations subjected to vertical loads. Special attention is given to the improved analytical method (YS-MAT) that reflects the mat flexibility and soil spring coupling effect. The soil model captures the stiffness of the soil springs as well as the shear interaction between the soil springs. The proposed method has been validated by comparing the results with other numerical approaches and field measurements on mat foundation. Through comparative studies, the proposed analytical method was in relatively good agreement with them and capable of predicting the behavior of the mat foundations.

• Wind and Structures
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• 제7권4호
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• pp.281-291
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• 2004

The flutter characteristics of long span bridges are discussed from the point of the unsteady pressure distribution on bridge deck surface during heaving/torsional vibration related to the aerodynamic derivatives. In particular, it is explained that the coupling terms, which consist of $A_1^*$ and $H_3^*$, play a substantial role on the coupled flutter, in comparison with the flutter characteristics of various structural sections. Also the effect of the torsional/heaving frequency ratio of bridge structures on the flutter instability is discussed from the point of the coupling effect between heaving and torsional vibrations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.475-480
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• 2000

The transient dynamic-response analysis of fuel-storage tanks of flying vehicles accelerating in the vertical direction is achieved with finite element method. A fuel-storage tank is a representative example of the fluid-structure interaction problem, in which structure and fluid media interact strongly. For the accurate analysis of this complicated fluid-structure system, we employed ALE(arbitrary Lagrangian-Eulerian) coupling method. Two types of fuel-storage tanks, one with two baffles and the other without baffle, are considered to examine the effect of baffles. The fuel-storage tank with baffles shows more uniform hydrodynamic pressure distribution, resulting effective stress in structural region and faster convergence from transient to steady states. MSC/Dytran, a commercial FEM software for the 3D coupled dynamic analysis, is used for this analysis.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2006년도 춘계학술발표대회
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• pp.1049-1052
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• 2006

차세대의 무선 네트워크 기술은 기존의 망을 통합하고 IP화 하는 방향으로 발전중이며, WWAN과 WLAN의 통합망에 관한 연구가 활발히 진행 중이다. 본 연구는 최근 상용화 서비스가 이루어지고 있는 WDMB 기술을 WWAN, WLAN과 강결합(Tight Coupling) 방식으로 통합한 네트워크 환경을 제안한다. 본 연구에서 제안하는 수직적 핸드오프(Vertical Handoff) 기법은 WLAN 인터페이스를 필요한 상황에만 구동하여 에너지 소모율을 낮춘다. 또한 WDMB 인터페이스를 상시 구동하여 데이터 트래픽이 발생할 때에 곧바로 WDMB 인터페이스를 통해 데이터 전송을 시작하여 전송률을 높인다. 또한 성능 평가를 통하여 단말에 장착된 모든 인터페이스를 구동하는 방식과 비교하여 에너지 소모율이 경감되었으며, 단말에 장착된 한 가지 인터페이스만을 구동하는 방식과의 비교를 통해 데이터 전송률이 크게 향상되었음을 보인다.

• 대한기계학회논문집A
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• 제21권11호
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• pp.1809-1818
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• 1997

Mathematical models of industrial robots or manipulators are highly nonlinear equations with nonlinear coupling between the variables of motion. As the working speed has been fast, the effects of nonlinear terms have become serious. So the control algorithm based on approximately linearized equation looses the efficiency. In order to design the control law for the nonlinear models, Hunt-Su's nonlinear transformation method and Marino's feedback equivalence condition are used with linear quadratic regulator(LQR) theory in this study. Nonlinear terms of the system are eliminated and coupled terms are decoupled by this feedback law. This method is applied to a 3-D.O.F. vertical articulated manipulator by both experiments and simulations and compared with PID control which is widely used in the industry.