• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.244-249
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• 1998

In this paper, the hybrid state space self-tuning control technique Is studied within the framework of fuzzy systems and dual-rate sampling control theory. We show that fuzzy modeling techniques can be used to formulate chaotic dynamical systems. Then, we develop the hybrid state space self-tuning fuzzy control techniques with dual-rate sampling for digital control of chaotic systems. An equivalent fast-rate discrete-time state-space model of the continuous-time system is constructed by using fuzzy inference systems. To obtain the continuous-time optimal state feedback gains, the constructed discrete-time fuzzy system is converted into a continuous-time system. The developed optimal continuous-time control law is then convened into an equivalent slow-rate digital control law using the proposed digital redesign method. The proposed technique enables us to systematically and effective]y carry out framework for modeling and control of chaotic systems. The proposed method has been successfully applied for controlling the chaotic trajectories of Chua's circuit.

• 한국전산구조공학회논문집
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• 제37권2호
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• pp.85-93
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• 2024

이 논문에서는 파랑 하중을 받는 부유식 구조체의 운동 해석에 있어서 시스템 식별 방법을 이용한 상태공간방정식 모델을 수립하고 해석하는 방법을 제안하였다. 상태공간방정식 모델의 수립 방법으로는 주파수영역에서 하중-변위 입출력 관계에 대한 목표 전달함수를 구하고 이에 가장 근접하는 상태공간방정식을 구하는 절차를 제시하였다. 전통적으로 부유식 구조체 운동의 시간영역 해석은 지연함수의 합성곱적분을 포함하는 Cummins 방정식을 시간적분하여 이루어진다. 상태공간방정식 모델은 이러한 시간영역해석을 효과적으로 수행하기 위한 방법의 하나로서 연구되어 왔다. 제안하는 방법에서는 시스템 식별방법인 N4SID 와 전달함수의 분모 및 분자 다항식의 계수를 설계변수로 하는 최적화방법을 사용하여 목표 전달함수에 상응하는 상태공간방정식을 구한다. 제안하는 방법의 적용성을 보이는 예제로서 단자유도 수치모델 및 6자유도 바지의 운동을 해석하였다. 제시하는 상태공간방정식 모델은 주파수영역 및 시간영역에서 모두 기존의 해석결과와 잘 일치하고 시간영역해석에서는 계산의 정확도를 확보하면서 계산 시간을 크게 줄일 수 있음을 확인하였다.

• 대한수학회논문집
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• 제10권3호
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• pp.715-733
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• 1995

We present a transient queue size distribution for $M/G/m/N$ queue with state dependent arrival rates, using the diffusion process with piecewise constant diffusion parameters, with state space [0, N] and elementary return boundaries at x = 0 and x = N. The model considered here contains not only many basic model but the practical models such as as two-node cyclic queue, repairmen model and overload control in communication system with finite storage buffer. For the accuracy check, we compare the approximation results with the exact and simulation results.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1146-1155
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• 2017

Normally, the artificial intelligence algorithms are widely applied to the optimal controller design. Then, it is expected that the best output performance is achieved. Unfortunately, when resulting controller parameters are implemented by using the practical devices, the output performance cannot be the best as expected. Therefore, the paper presents the optimal controller design using the combination between the state-space averaging model and the adaptive Tabu search algorithm with the new criteria as two penalty conditions to handle the mentioned problem. The buck-boost converter regulated by the cascade PI controllers is used as the example power system. The results show that the output performance is better than those from the conventional design method for both input and load variations. Moreover, it is confirmed that the reported controllers can be implemented using the realistic devices without the limitation and the stable operation is also guaranteed. The results are also validated by the simulation using the topology model of MATLAB and also experimentally verified by the testing rig.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제8권4호
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• pp.264-269
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• 2008

In this paper, two neural networks as a material model, which are based on the state-space method, have been proposed. One outputs the rates of inelastic strain and material internal variables whereas the outputs of the other are the next state of the inelastic strain and material internal variables. Both the neural networks were trained using input-output data generated from Chaboche's model and successfully converged. The former neural network could reproduce the original stress-strain curve. The neural network also demonstrated its ability of interpolation by generating untrained curve. It was also found that the neural network can extrapolate in close proximity to the training data.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2606-2611
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• 2003

Comprehensive study on the control system design for a RTP process has been conducted. The purpose of the control system is to maintain maximum temperature uniformity across the silicon wafer achieving precise tracking for various reference trajectories. The study has been carried out in two stages: thermal balance modeling on the basis of a semi-empirical radiation model, and optimal iterative learning controller design on the basis of a linear state space model. First, we found through steady state radiation modeling that the fourth power of wafer temperatures, lamp powers, and the fourth power of chamber wall temperature are related by an emissivity-independent linear equation. Next, for control of the MIMO system, a state space modeland LQG-based two-stage batch control technique was derived and employed to reduce the heavy computational demand in the original two-stage batch control technique. By accommodating the first result, a linear state space model for the controller design was identified between the lamp powers and the fourth power of wafer temperatures as inputs and outputs, respectively. The control system was applied to an experimental RTP equipment. As a consequence, great uniformity improvement could be attained over the entire time horizon compared to the original multi-loop PID control. In addition, controller implementation was standardized and facilitated by completely eliminating the tedious and lengthy control tuning trial.

• 한국게임학회 논문지
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• 제4권1호
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• pp.58-66
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• 2004

본 논문에서는 반례를 도달성 게임 풀이에 활용했다. 도달성 게임이란, 게임 규칙을 준수하면서 초기 상태에서 목표 상태로 가는 경로를 찾는 것이다. 게임의 초기 상태를 유한 상태 모델로 표현하고 목표 상태의 부정(오답)을 시제 논리식으로 표현해서 모델 검사기에 입력하면, 반례로 오답에 대한 부정 즉 정답을 출력한다. 다시 말해서 반례로 출력된 것이 문제를 해결하는 정답인 것이다. 이와 같은 아이디어를 푸쉬푸쉬 게임 풀이에 적용했다. 그 결과 크기가 작은 푸쉬푸쉬 게임의 경우 게임을 해결하는 최단 경로를 쉽게 찾아냈다. 그러나 게임의 크기가 큰 경우 제한된 시간(실험에서는 3시간)내에 찾아내지 못했다. 왜냐하면 게임의 크기가 커질 경우 검사해야할 상태의 수가 지수적으로 증가하는 상태 폭발 문제가 발생했기 때문이다. 상태 폭발 문제를 해결하기 위해 추상화 기법을 이용해서 검사해야 할 상태공간을 축소하였다. 상태 공간을 줄인 결과, 기존 모델체킹으로 해결하지 못했던 게임을 풀 수 있었다.

• 대한전기학회논문지
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• 제36권4호
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• pp.301-304
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• 1987

The Optimal Control Problems for the singular system with the Generalized state space model are considered. It is shown that when the system is singular, the dimension can be reduced by coordinate transformation and the equivalent nonsingular system is got. After we have nonsingular system, the solution for the optimal control problem can be got by Riccati equation.

• 대한전기학회논문지
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• 제33권12호
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• pp.491-496
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• 1984

The optimal control and filtering problems for the systems with the generalized state space model are considered and the generalized Riccati equation is derived. Also the algorithm for the solution of the generalized algebraic Riccati equation is developed and it is shown that the algotithm can be applied to the case where the matrix R is singular or near singular.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.483-484
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• 2019

This paper proposes a harmonic state space (HSS) modeling of DC microgrid. In the HSS model, nonlinear equations for the switched circuit model are transformed into multiple linear equations. The simulation results have shown the HSS modeling is comparable with PSIM simulation.