• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.124-127
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• 2005

As computer capability and test skill become more and more advanced, finite element method and modal test are being widely applied in engineering design. In order to correlate and reconcile the inevitable discrepancies between the analytical and experimental models, many techniques have been developed. Among these methods, multiple-system methods are known as the effective tools in that they can supply the rich modal data available which are experimentally obtained. These abundant modal data can help structural system parameters estimated well. Multiple-system methods can be classified into the structural modification methods and feedback controller methods. The structural modification methods need the physical attachment of structures and their concept may limit the application of them. To overcome this drawback, the feedback controller methods are addressed which enable us to get more modal data without the structural change. Mode decoupling controller(MDC), one of them, is to use acceleration out)ut feedback to perturb an open-loop system. The output feedback controller generally cannot guarantee the stability of a closed-loop system. However, MDC can solve this problem under the certain constraints. So far, MDC utilizes accelerations as the sensor signals. In this research, strain sensors are going to be picked up to apply to the MDC. Strain output is recently used for structural system identification due to the drastically improved and miniaturized strain sensor. In this paper, we show that the MDC using strain output has differences compared with acceleration output in estimating the structural system parameters. The associated simulation is performed to demonstrate the above mentioned characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.523-525
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• 2005

This paper deals with a linear matrix inequality (LMI) approach to the design of a static output feedback controller that simultaneously stabilizes a finite collection of linear time-invariant plants. Simultaneous stabilization by static ouput feedback is represented in terms of LMIs with a rank condition. An iterative penalty method is proposed to solve the rank-constrained LMI problem. Numerical experiments show the effectiveness of the proposed algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.59.3-59
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• 2002

$\textbullet$ Contents 1: Preliminaries on passivity and feedback passivity $\textbullet$ Contents 2: Assumptions in the paper $\textbullet$ Contents 3: Adaptive output feedback controllers $\textbullet$ Contents 4: Adaptive disturbance attenuation $\textbullet$ Contents 5: Adaptive passification $\textbullet$ Contents 6: An illustrative numerical example

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.493-500
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• 2018

This paper addresses a decentralized observer-based output-feedback formation control problem for multiple unmanned underwater vehicles (UUVs). The complex nonlinear model for a UUV is feedback-linearized. It is assumed that each UUV in the formation exploits only the information regarding itself and the immediate predecessor, which imposes structural constraints on the formation controller gain matrices. The design condition is presented as a two-stage linear matrix inequalities problem. The synthesized controller demonstrates its own advantages through a numerical example.

• 전기전자학회논문지
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• 제9권1호
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• pp.72-78
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• 2005

본 논문은 단일입력 단일출력 비선형 계통에 대해서 강인한 출력궤환 제어기를 제시한다. 이전의 출력궤환 비선형 제어기가 모두 동적인 관측기 기반으로 설계된 반면 본 논문에서는 출력의 과거값들만을 이용하여 상태변수를 추정하는 새로운 방식을 제안하고 이를 후방차분 상태추정기라 명했다. 실제 상태변수값과 추정치와의 오차를 보상하기 위해서 제어입력에 강인제어항을 추가하였고 그것의 이득을 자동으로 조정하는 적응 알고리듬을 채택했다. 전체 폐루프 시스템은 출력 추종 오차가 점근적으로 안정하도록 그리고 모든 신호가 유계이도록 제어입력과 적응법칙이 설계된다. 제시된 제어기를 역진자 계통에 적용한 모의실험을 통해서 성능을 검증하였다.

• 전력전자학회논문지
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• 제4권2호
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• pp.175-183
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• 1999

PWM 컨버터에서 직류출력전압의 빠른 응답을 위해 입력 및 출력의 전력평형개념을 시스템 모델링에 도입하는 것이 바람직하다. 이 경우 시스템은 비선형이 되며 제어기 설계가 용이하지 않다. 본 논문에서는 입출력 궤환선형화 기법을 응용하여 시스템의 비선형성을 제거하였으며 그 결과 빠른 전압응답특성을 얻을 수 있었다. 또한 작은 용량의 전해커패시터를 사용하더라도 부하변동에 대해 직류출력전압을 일정하게 유지하는 것이 가능함을 보였다.

• 전기전자학회논문지
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• 제23권4호
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• pp.1353-1359
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• 2019

It is presented in this paper that the static output feedback (SOF) pole-assignment problem of some linear time-invariant systems can be completely resolved by parametrization in real Grassmann space. For the real Grassmannian parametrization, the so-called Plucker matrix is utilized as a linear matrix formula formulated from the SOF variable's coefficients of a characteristic polynomial constrained in Grassmann space. It is found that the exact SOF pole assignability is determined by the linear independency of columns of Plucker sub-matrix and by full-rank of that sub-matrix. It is also presented that previous diverse pole-assignment methods and various computation algorithms of the real SOF gains for 2-input, 2-output, 4^th order systems are unified in a deterministic way within this real Grassmannian parametrization method.

• 소음진동
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• 제9권1호
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• pp.70-76
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• 1999

This paper presents a pseudo-sensor-output-feedback(PSOF) method for the vibration suppression of the flexible piezoelectric smart structures. This method reduces the modeling errors using pseudo sensors in the output equation formulation. It also reduces computation time in practice. since the output equation does not need the state observer required in the state space equation. Experimental works are performed for the validation of theoretical predictions with the piezoelectric sensor and actuator bonded on the cantilever beam. An algorithm based on the sliding mode control theory is developed and analyzed for the robustness to the modeling errors and parameter uncertainties. This study also discusses the characteristics of the active and semi-active systems.

• 대한전기학회논문지
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• 제40권7호
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• pp.706-717
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• 1991

In order to remove the assumption of full state availability which is one of the major difficulties with the practical realization of variable structure control systems,a new switching function with a dynamic structure is proposed. And the control performances of the output feedback variable structure control systems with the dynamic switching function are evaluated through simulation studies. The proposed dynamic switching function is driven by small number of measured output and input variables while conventional static switching function requires full state information. Therefore, the proposition of the dynamic swiching function makes practical implementation of output feedback variable structure control scheme possible for the systems with unmeasurable state variables, high order systems and large scale systems that the conventional variable structure control schemes with static switching function cannot be applied. In the variable structure control systems with the dynamic switching function, desired control performance can be guaranteed by proper choice of design parameters such as poles of switching function dynamic equation and switching control gains even though small number of measured output and input variables are provided as shown in simulation resuls.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권4호
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• pp.189-197
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• 2003

The problem of designing a parallel feedforward compensator (PFC) is considered for a class of non-square linear systems such that the closed-loop system is strictly passive. If a given square system has (vector) relative degree one and is weakly minimum phase, the system can be rendered passive by a state feedback. However, when the system states are not always measurable and the given output is considered, passivation (i.e. rendering passive) of a non-minimum phase system or a system with high relative degree cannot be achieved by any other methodologies except by using a PFC. To passivate a non-square system we first determine a squaring gain matrix and design a PFC such that the composite system has relative degree one and is minimum phase. Then the system is rendered strictly passvie by a static output feedback law. Necessary and sufficient conditions for the existence of the PFC and the squaring gain matrix are given by the static output feedback formulation, which enables to utilize linear matrix inequality (LMI). As an application of the scheme, an alternative way of replacing the role of velocity measurements is provided for the PD-control law of a convey-crane system.