• 한국지진공학회논문집
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• 제5권6호
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• pp.37-46
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• 2001

본 연구에서는 부분적으로 정상상태 확률과정으로 모델링할 수 있는 가진입력에 대하여 확률적으로 정의된 구조물의 최대응답에 대한 구속조건을 만족시키면서 제어력을 최소화 할 수 있는 최적설계 방법을 제안한다. 최적화 과정에서 안정성의 확보를 위해 제어기를 전상태 피드백 LQR제어기의 형태로 한정하였으며 가중치 행렬을 설계변수로 하고 Riccati 행렬을 매개변수로 하여 목적함수와 구속조건 함수 및 그 기울기를 계산한다. 제안된 방법을 통해 설계된 전상태 피드백 LQR제어기는 목표 응답성능을 만족시킬 수 있었고 이에 필요한 최대 제어력을 확률적으로 정량화하여 제어금기의 제작에 유용한 자료가 될 수 있도록 하였다. 상태변수 추정을 위해 독립적으로 설계된 Kalman 필터와 최적화된 LQR 제어기가 결합된 LQG 제어기 및 그 차수를 축소시킨 제어기는 모두 큰 성능의 저하가 없었으며 따라서 제안된 설계방법을 이용하여 구조물의 최대응답에 관한 구속조건을 만족시키는 출력 피드백 제어기 설계가 충분히 가능함을 확인하였다.

• 전자공학회논문지T
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• 제36T권2호
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• pp.21-31
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• 1999

대규모 시스템 제어와 관련하여 몇 개의 부시스템으로 분할하여 처리하는 계층별 제어이론이 많이 연구되어 왔으며 특히 치수가 높은 대규모 비선형 시스템의 경우에 고차의 비선형 미분방정식을 동시에 적분을 해야하고 많은 계산량을 필요로 하므로 해를 구하기가 어려운 문제가 있다. 1980년대 Singh과 Hassan은 상호예측 알고리즘(two level prediction algorithm)을 제시한바 있고 이 방법은 비선형 대규모 시스템의 최적제어에 효과적이나 시스템 행렬 Q, R, S, H에 따라 제한된 최적화 구간에서만 성립되는 등 최적화 구간의 길이와 수렴성 여부가 행렬 값에 영향을 받는 알고리즘상의 단점이 있다. 본 연구에서는 수렴조건으로부터 평가함수에 구속조건(quadratic penalty term)을 부여하지 않는 새로운 개선된 알고리즘을 제시 적용하여 시스템 행렬 결정을 위한 과정 없이 수렴속도의 향상과 함께 최적의 수렴성 및 최적화 구간을 얻도록 했다. 분할된 비선형 시스템의 최적제어를 위해서는, 대수 반복연산만으로 2점 경계치 문제(two point boundary value problem)를 해결함으로써 기존의 수치 해석법에 비해 연산이 간단한 블록펄스 변환 방법을 사용해서 처리했다.

• 대한토목학회논문집
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• 제5권3호
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• pp.1-12
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• 1985

저수지계(貯水池系)의 최적운영(最適運營)은 다차원문제(多次元問題)로서 일반적으로 O.R. 기법(技法)으로 해를 구할 수 있다. 본(本) 연구(硏究)에서는 선형추적리론(線型追跡理論)을 이산화(離散化)하여 2점(點) 경계치문제(境界値問題)를 풀었다. 이 이론의 적용에는 두가지 문제가 제기되는데 첫째, 추적(追跡)을 위한 기준(基準)이 미지수(未知數)이므로 무제약(無制約) 조건(條件)의 최적률(最適律)을 반복 적용하여 수렴치(收斂値)를 구하여 이로부터 추적기준(追跡基準)을 산출했다. 둘째, 상태 및 제어벡터의 제약조건(制約條件)의 처리는 Pontryagin의 최소원리(最小原理)로 해결하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1318-1320
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• 1999

Recently, according to the growth of national economy and the improvement of lining conditions, electric power demand is increasing gradually. So it is being examined to construct large thermal power plants or nuclear plants. For the effective use of lands and for the economy of generations sites, the distance between generation and demand locations becomes farther and farther. At the same time, people desire higher quality or electric power. So in this paper, the optimal modulation controller for HVDC transmission system are designed by a recursive algorithm that determines the state weighting matrix Q of a linear quadratic performance. It means that the application of optimal modulation controller in HVDC transmission system can contribute the propriety to the improvement of the stability in HVDC transmission system.

• 대한기계학회논문집
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• 제17권6호
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• pp.1381-1388
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• 1993

본 연구에서는 구조계와 제어계가 결합된계에 대하여, 성능 평가함수의 구조 설계변수에 대한 감도를 Riccati방정식으로부터 직접 해석할 수 있는 효율적인 방안을 제시하여 동시최적설계가 가능토록한다. 그리고 유색잡음의 불규칙 노면입력을 받는 차체탄성을 고려한 Hac의 2륜 차량의 모델에 LQG제어를 행한 경우에 대하여, 본 연구 방법을 적용시켜 동시 최적화를 수행한 제어성능 특성을 종래의 최적제어만에 의한 제어성능과 비교, 검토 한다. 구조설계변수로는 현가장치의 강성특성, 감쇠특성 및 현가장치 지지점의 위치로 선정한다.

• 한국생산제조학회지
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• 제26권1호
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• pp.144-149
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• 2017

There have been lots of interest on service and entertainment robots. To ensure that robots work in harmony with humans, their stability and compactness are some of the key issues. Obviously, robots with fewer wheels occupy a smaller floor area compared to those with more wheels. In addition, robots with fewer wheels, whose posture stabilities are maintained by feedback control, are stable even under larger accelerations and/or higher locations of the center of mass. To facilitate controller design, it is assumed that both pitch and roll dynamics are decoupled. The dynamic equations of motion for the proposed robot are derived from the Euler-Lagrange equation. To obtain the optimal balancing control law, linear quadratic regulator control methods are applied to the linearized dynamic equations. Simulation and experimental results verify the effectiveness and performance of the proposed balancing control algorithm for a single-wheeled mobile robot.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.444-449
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• 2009

An engine is one of the most dominant noise and vibration sources in vehicle systems. Therefore, in order to resolve noise and vibration problems due to engine, various types of engine mounts have been proposed. This work presents a new type of active engine mount system featuring a magneto-rheological (MR) fluid and a piezostack actuator. As a first step, six degrees-of freedom dynamic model of an in-line four-cylinder engine which has three points mounting system is derived by considering the dynamic behaviors of MR mount and piezostack mount. In the configuration of engine mount system, two MR mounts are installed for vibration control of roll mode motion whose energy is very high in low frequency range, while one piezostack mount is installed for vibration control of bounce and pitch mode motion whose energy is relatively high in high frequency range. As a second step, linear quadratic regulator (LQR) controller is synthesized to actively control the imposed vibration. In order to demonstrate the effectiveness of the proposed active engine mount, vibration control performances are evaluated under various engine operating speeds (wide frequency range) and presented in time domain.

• 한국소음진동공학회논문집
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• 제19권6호
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• pp.583-590
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• 2009

An engine is one of the most dominant noise and vibration sources in vehicle systems. Therefore, in order to resolve noise and vibration problems due to engine, various types of engine mounts have been proposed. This work presents a new type of active engine mount system featuring a magneto-rheological (MR) fluid and a piezostack actuator. As a first step, six degrees-of freedom dynamic model of an in-line four-cylinder engine which has three points mounting system is derived by considering the dynamic behaviors of MR mount and piezostack mount. In the configuration of engine mount system, two MR mounts are installed for vibration control of roll mode motion whose energy is very high in low frequency range, while one piezostack mount is installed for vibration control of bounce and pitch mode motion whose energy is relatively high in high frequency range. As a second step, linear quadratic regulator (LQR) controller is synthesized to actively control the imposed vibration. In order to demonstrate the effectiveness of the proposed active engine mount, vibration control performances are evaluated under various engine operating speeds(wide frequency range) and presented in time domain.

• 한국해양공학회지
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• 제19권2호
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• pp.67-73
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• 2005

This paper describes depth, heading and speed control of an underwater vehicle that has four stern thrusters of which forces are coupled in the diving and, steering motion, as well as the speed of the vehicle. The optimal linear quadratic controller is designed based on a linearized- state space model, developed by combining the dynamic equations of speed, steering and diving motion. The designed controller gives provides an optimal thrust distribution, minimizing the given performance index to control speed, depth and heading simultaneously. To validate the performance of the controller, a simulation and tank-test are carried out with DUSAUV (Dual Use Semi-Autonomous Underwater Vehicle), developed by KORDI as a test-bed for testing new underwater technologies. Optimal gains of the controller are tuned, using a computer simulation environment with a nonlinear 6-DOF numerical DUSAUV model, developed by PMM (Planner Motion Mechanism) test. To verify the performance of the presented controller in experiment, a tank-test with DUSAUV is carried out in the ocean engineering basin in KORDI. The experimental results are also compared with the simulation results to investigate the accordance of the numerical and the real mode.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1979년도 하계 전자.전기연합학술발표회논문집
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• pp.119-120
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• 1979

A linear state equation of the first order differential form relating the load-frequency dynamic characteristics of interconnected power systems was derived for use in computer simulation. A now solution of the algebraic matrix riccati equation for application in quadratic optimal controllor and least-square state estimator dermination was developed. The program for a dynamic state equation for two interconnected control areas was developed. The optimized load-frequency deviation was analysed and a numerical analysis was tried based on the computer simulation. It was shown that the dynamic response of th loed-frequency could be optimized with weighting factors IR and Q. The result was that the load-frequency and the tie-line deviation were visibly reduced.