• 제목/요약/키워드: state-space equation

검색결과 305건 처리시간 0.027초

Stochastic control approach to reliability of elasto-plastic structures

  • Au, Siu-Kui
    • Structural Engineering and Mechanics
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    • 제32권1호
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    • pp.21-36
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    • 2009
  • An importance sampling method is presented for computing the first passage probability of elasto-plastic structures under stochastic excitations. The importance sampling distribution corresponds to shifting the mean of the excitation to an 'adapted' stochastic process whose future is determined based on information only up to the present. A stochastic control approach is adopted for designing the adapted process. The optimal control law is determined by a control potential, which satisfies the Bellman's equation, a nonlinear partial differential equation on the response state-space. Numerical results for a single-degree-of freedom elasto-plastic structure shows that the proposed method leads to significant improvement in variance reduction over importance sampling using design points reported recently.

세 개의 마이크로스트립 전송선로간의 크로스톡 (Crosstalk among three microstrip transmission lines)

  • 최재연;이상설
    • 전자공학회논문지D
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    • 제34D권5호
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    • pp.14-21
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    • 1997
  • The crosstalk among three identical uniform coupled microstrip transmissiom lines is examined. To analyze the crosstalk, the simultaneous equations for the voltage and current waves on each transmission line are induced from the transmission line equation. The capacitance and the inductance of the line to solve the transmission line equation are calculated by the spectral domain analysis and the space domian analysis. There are three quasi-TEM modes is three microstrip transmission lines and the characteristics mode impedences in each mode are almost equal at a weak coupling state. The crosstalk among three identical microstrip transmission lines is calculated varying the frequency from 50MHz to 3GHz.

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Homogeneous Robust Systems Control On Limitations In The Space State

  • Kim, Dong-Hwa;Kawagi, Shigeyasa
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.159.2-159
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    • 2001
  • The new approach of homogeneous robust control systems synthesis, both linear, and nonlinear and non-stationary is offered. The control is carried out, providing the given phase constrains varied in acceptable limits, in view of constrains on its value and incompleteness of the information about functioning disturbances. The approach is based on introduction of auxiliary integral surfaces, on which the initial moving is projected. As a result the reduced equivalent moving is forming, described by the scalar equation which in many important cases can be integrated directly. On the basis of the obtained equation solving of a synthesis task is carried out and can be reduced to algebraic or integral inequalities. The final relations defined for linear equivalent moving are presented.

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ER밸브를 이용한 자동 하역 시스템의 제어 (II) -하역시스템의 모델링 및 제어- (Control of Automatic Cargo Handling System Using ER Valves (II) -Modeling and Control of Cargo Handling System-)

  • 성금길;정달도;최승복
    • 한국정밀공학회지
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    • 제18권9호
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    • pp.53-60
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    • 2001
  • This paper presents a position control of a platform at the seaport cargo handling system. After brief description of the operating principles of the cargo handling system, the governing equation of the moving platform is derived. The equation is described in the state space model, and a robust H$_{\infty}$ controller to achieve position tracking of the moving platform. which can carry 200ton of containers, is formulated. In the synthesis of the controller, the weight of the container is treated as uncertain parameter. Both regulating and tracking control responses are analyzed for the loading and unloading procedures of the proposed automatic cargo handling system.

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섭동 시스템에 대한 규정된 원 내로의 극점배치 견실성 해석 (Robustness analysis of pole assignment in a specified circle for perturbed systems)

  • 김가규;최봉열
    • 제어로봇시스템학회논문지
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    • 제1권2호
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    • pp.78-82
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    • 1995
  • In this paper, we consider the robustness analysis problem in state space models with linear time invariant perturbations. Based upon the discrete-time Lyapunov approach, sufficient conditions are derived for the eigenvalues of perturbed matrix to be located in a circle, and robustness bounds on perturbations are obtained. Spaecially, for the case of a diagonalizable hermitian matrix the bound is given in terms of the nominal matrix without the solution of Lyapunov equation. This robustness analysis takes account not only of stability robustness but also of certain types of performance robustness. For two perturbation classes resulting bounds are shown to be improved over the existing ones. Examples given include comparison of the proposed analysis method with existing one.

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벡터제어 유도전동기의 모델추종 견실제어기 설계 (The Model-Following Robust Controller Design for the Vector-Controlled Induction Motor)

  • Chi Hwan Lee
    • 전자공학회논문지B
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    • 제30B권11호
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    • pp.93-101
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    • 1993
  • The transfer function of vector-controlled induction motor is represented along with both unstructured and structured uncertainty such as the error of rotor time constant and current ripple. The low-pass-filter behavior of a magnetizing inductance gets rid of unstructured uncertainty in the transfer function. The robust controller to compensate variation of the transfer function is designed using simple P-I linear controllers. The coefficients of speed PI controller are determined from an overshoot and a rising time of system and the coefficients of model-following PI controller are obtained using the solution of Riccati equation of LQR control in the state space equation of the error system. Experimental results with the DSP-based model-following robust controller are shown a good robustness against the structured uncertainty of the motor.

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Vibration of piezo-magneto-thermoelastic FG nanobeam submerged in fluid with variable nonlocal parameter

  • Selvamani Rajendran;Rubine Loganathan;Murat Yaylaci;Ecren Uzun Yaylaci;Mehmet Emin Ozdemir
    • Advances in nano research
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    • 제16권5호
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    • pp.489-500
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    • 2024
  • This paper studies the free vibration analysis of the piezo-magneto-thermo-elastic FG nanobeam submerged in a fluid environment. The problem governed by the partial differential equations is determined by refined higher-order State Space Strain Gradient Theory (SSSGT). Hamilton's principle is applied to discretize the differential equation and transform it into a coupled Euler-Lagrange equation. Furthermore, the equations are solved analytically using Navier's solution technique to form stiffness, damping, and mass matrices. Also, the effects of nonlocal ceramic and metal parts over various parameters such as temperature, Magnetic potential and electric voltage on the free vibration are interpreted graphically. A comparison with existing published findings is performed to showcase the precision of the results.

가스터빈 블레이드의 신뢰성 해석 (Reliability Analysis of Gas Turbine Engine Blades)

  • 이광주;임성한;황종욱;정용운;양계병
    • 한국항공우주학회지
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    • 제36권12호
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    • pp.1186-1192
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    • 2008
  • 가스터빈 엔진 블레이드의 신뢰성을 해석하였다. 항복강도, 탄성계수, 엔진속도 및 기체온도를 서로 독립적인 확률변수로 가정하였다. 파손확률을 구하기 위하여 사용한 방법들 중에서 Advanced Mean Value Method가 가장 효율적임을 알 수 있었다. 동일한 평균과 표준편차를 갖는 정규, 대수정규 및 Weibull 분포로 확률변수 형상을 가정하였을 경우, 극한상태방정식의 누적분포함수는 확률변수 분포형상에 의하여 큰 영향을 받지 않음을 알 수 있었다. 확률변수의 표준편차에 대한 파손확률의 민감도는 기체온도의 경우에 가장 크다는 것을 알 수 있었다. 확률변수의 평균과 표준편차의 효과를 검토하였다. 기체온도의 평균과 엔진속도의 표준편차의 증가가 파손확률을 가장 크게 증가시킴을 알 수 있었다.

액체로켓 추력실에서 발생하는 Heat Flux에 관한 실험적 연구 (An Experimental study for the heat flux in liquid rocket thrust chamber)

  • 안원근;박희호;황수권;김유
    • 한국항공우주학회지
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    • 제31권3호
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    • pp.65-71
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    • 2003
  • 일반적으로 액체로켓 엔진의 추력실에서 연소중 어느 정도의 열 유속을 발생하는가를 아는 것은 추력실을 냉각하기 위한 가장 중요한 사항 중에 하나이다. 이에 본 연구에서는 Kerosen/LOx를 추진제로 사용하는 소형 액체로켓 엔진의 추력실에서 발생하는 heat flux를 측정하기 위하여 thin wall chamber를 제작하였다. wall thickness는 1mm로 하였으며 추력실 외벽에 총 9개의 열전쌍을 부착하여 연소시험을 수행함으로써 연소중 변화하는 추력실의 외벽온도를 측저하였다. System을 1차원 비정상상태로 가정하고 측정된 추력실의 외벽온도로부터 one-dimensional the transient energy equation을 이용하여 추력실에서 발생하는 열유속 및 열전달계수를 예측하였다. 혼합비 2,0의 조건에서 실험변수로서 연소압에 변화를 주었으며 실험결과 열전달계수가 연소압에 0.88승에 비례하는 관계식을 얻어낼 수 있었다.

진동시험을 이용한 원자력발전소 캐비닛 구조의 지진응답예측기법 (Seismic Response Prediction Method of Cabinet Structures in a Nuclear Power Plant Using Vibration Tests)

  • 구기영;취진타오;조성국;김두기
    • 한국지진공학회논문집
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    • 제12권5호
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    • pp.57-63
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    • 2008
  • 본 연구는 원자력발전소에 설치되는 캐비닛형 전기기기의 동적 진동시험 자료를 이용하여 캐비닛의 지진응답을 예측할 수 있는 기법을 제안하였다. 제안된 기법은 1) 절점질량 이상화 모델에 기반한 등가 지진하중 산정, 2) 진동시험자료에 기반한 캐비닛 구조의 입출력 상태방정식 규명, 3) 산정된 등가지진하중과 규명된 입출력 상태방정식을 사용한 지진응답산정의 과정으로 구성된다. 제안된 기법은 유한요소기법(FEM) 모델 개선(Model Updating)에 기반한 지진응답예측기법에 비하여 모델링 오차가 개입 되지 않는 장점을 가진다. 캐비넷 구조를 이상화한 2차원 프레임 모델과 3차원 상세 모델에 대한 수치검증을 통하여 제안된 기법이 지진응답을 매우 정확하게 예측을 함을 관찰하였고, 측정 노이즈에 대해서도 강인함을 관찰하였다. 추후연구로 실험검증이 요구된다.