• 무역학회지
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• 제45권5호
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• pp.117-139
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• 2020

In case of international long-term transactions, there are various risks of economic change of circumstances including skyrocketing price increase and shortage of raw material, as well as force majeure in a general sense. Nevertheless, pretty many of international long-term commercial contracts do not include the provisions of renegotiation and adaptation of the contract. In this case, possibility of renegotiation and adaptation depends mainly on the applicable law. Namely, it may be possible or not, according to choice of law. The reason is that national laws have nuances each other, and most of national courts are traditionally reluctant to accept hardship. and also, provisions of international uniform law (CISG) has ambiguity and inflexibility in relation to the problems of change of circumstances. Accordingly, this paper analyzes comparatively the doctrines and provisions related to renegotiation and adaptation of contracts of the most representative countries such as England, U.S.A., France, Germany as well as provisions CISG and soft law such as PICC. By doing so, the author makes clear which laws of instruments is more flexible or acceptable in allowing renegotiation and adaptation of long-term commercial contracts, and emphasizes on the importance of inclusion of express terms by using other alternative supplementing clauses, as a best solution for settling the problems of legal uncertainty of contract in relation to renegotiation and adaptation.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 춘계학술대회 학술발표 논문집
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• pp.39-42
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• 1998

This paper proposes an adaptive fuzzy control scheme for a class of continuous-time nonlinear dynamic systems for which an explicit linear parameterization of the uncertainty is either unknown or impossible. In order to improve robustness under approximation errors and disturbances the proposed scheme includes deadzone in adaptation laws which varies its size adaptively. The assumption of known bounds on the approximation errors and disturbances is not required since those are estimated using adaptation laws. The overall adaptive scheme is proven to guarantee uniform ultimate boundedness in the Lyapunov sense.

• 한국항공우주학회지
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• 제41권2호
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• pp.98-106
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• 2013

본 논문에서는 슬라이딩 모드 제어와 간단한 적응 법칙을 이용하여 반작용 휠 고장에 대한 고장 허용 제어 법칙을 제안한다. 위성의 동역학식에 시스템 파라미터 오차와 고장 불확실성을 고려하여 자세 제어 법칙을 설계하였다. 고장은 구동기 고장인 반작용 휠 고장만을 고려하였으며, 반작용 휠 고장은 곱 형태로 반영된다. 제안된 자세 제어 법칙은 르야프노프 안정성 이론을 통해 안정성을 확인하였고, 수치 시뮬레이션을 통하여 기존의 슬라이딩 모드 제어기와 비교하였으며 위성의 자세 각속도가 안정화되지 않은 경우 제안된 적응 슬라이딩 자세 제어기가 고장에 더욱 빠른 응답 속도를 갖는 것을 확인하였다.

• 제어로봇시스템학회논문지
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• 제6권11호
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• pp.963-967
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• 2000

This paper deals with a sliding mode control with uncertainty adaptation for the robust stabilization of input-delay systems with unknown uncertainties. A sliding surface including a state predictor is employed to compensate for the effect of the input delay. The proposed method does not need a priori knowledge of upper bounds on the norm of uncertainties, but estimates those upper bounds by adaptation laws based on the sliding surface. Then, a robust control law with the uncertainty adaptation is derived to ensure the existence of the sliding mode. A numerical example is given to illustrate the design procedure.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.67.2-67
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• 2001

In the adaptive fuzzy sliding mode control, from a set of fuzzy IF-THEN rules adaptive fuzzy sliding mode control whose parameters are adjusted on-line according to some adaptation laws is constructed for the purpose of controlling the plant to track a desired trajectory. Most of the research works in nonlinear controller design using fuzzy systems consider the affine system with fixed grid-rule structure based on system state availability. The fixed grid-rule structure makes the order of the controller big unnecessarily, hence the on-line fuzzy rule structure and fuzzy observer based adaptive fuzzy sliding mode controller is proposed to solve system state availability problems. Therefore adaptive laws of fuzzy parameters ...

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2308-2310
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• 2001

In the adaptive fuzzy sliding mode control, from a set of a fuzzy IF-THEN rules adaptive fuzzy sliding mode control whose parameters are adjusted on-line according to some adaptation laws is constructed for the purpose of controlling the plant to track a desired trajectory. Most of the research works in nonlinear controller design using fuzzy systems consider the affine system with fixed grid-rule structure based on system state availability. The fixed grid-rule structure makes the order of the controller big unnecessarily, hence the on-line fuzzy rule structure and fuzzy observer based adaptive fuzzy sliding mode controller is proposed to solve system state availability problems. Therefore, adaptive laws of fuzzy parameters for state observer and fuzzy rule structure are established implying whole system stability in the sense of Lyapunov.

• 제어로봇시스템학회논문지
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• 제14권12호
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• pp.1226-1231
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• 2008

A design of attitude controller for a tiltrotor is presented augmenting L1 adaptive control, neural networks, and feedback linearization. The neural networks compensate for the modeling error caused by the lack of knowledge of tiltrotor dynamics while the L1 adaptive control allows high adaptation gains in adaptation laws thereby, satisfying tracking performance requirement. The efficacy of this control methodology is illustrated in high-fidelity nonlinear simulation of a tiltrotor by flying the tiltrotor in different flight modes from where the L1 adaptive controller with neural networks is originally designed for.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1996년도 추계학술대회 학술발표 논문집
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• pp.158-161
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• 1996

A robust adaptive tracking control architecture is proposed for a class of continuous-time nonlinear dynamic systems for which an explicit linear parameterization of the uncertainty in the dynamics is either unknown or impossible. The architecture employs an adaptive fuzzy system to compensate for the uncertainty of the plant. In order to improve the robustness under approximation errors and disturbances, the proposed architecture includes deadzone in adaptation laws. Unlike the previously proposed schemes, the magnitude of approximate errors and disturbances is not required in the determination of the deadzone size, since it is estimated using the adaptation law. The proposed algorithm is proven to be globally stable in the Lyapunov sense, with tracking errors converging to the proposed architecture.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.739-744
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• 2004

This paper presents an adaptive approach to control the amount of slip of the torque converter bypass clutch using its estimated friction coefficient. The proposed approach can be readily implemented using the inexpensive speed sensors currently installed in an automobile. A measurement feedback control law to drive the slip error to zero together with an adaptation law to identify the unknown friction coefficient is developed using the Lyapunov control design method. The robustness of the control and adaptation laws to parametric and/or torque uncertainties as well as the convergence of the friction coefficient are investigated. Simulation results verify the viability of the proposed control algorithm in real-world vehicle control applications.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.937-942
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• 1993

This paper extends the authors' prior work on the regulation of flexible space structures via partial feedback linearization (PFL) methods to articulated systems. Recursive relations introduced by Jain and Rodriguez are central to the efficient formulation of models via Poincare's form of Lagrange's equations. Such models provide for easy construction of feedback linearizing control laws. Adaptation is shown to be an effective way of reducing sensitivity to uncertain parameters. An application to a flexible platform with mobile remote manipulator system is highlighted.