• Title/Summary/Keyword: state-space equation

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Modeling and State Observer Design for Roll Slip in Cold Cluster Mills (냉간압연 다단 압연기의 롤 슬립 모델링 및 상태 관측기 설계)

  • Kang, Hyun Seok;Hong, Wan Kee;Hwang, I Cheol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.12
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    • pp.1543-1549
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    • 2012
  • This study focuses on the state space model and the design of a state observer for the slip dynamics between rolls in STS cold cluster mills. First, a mathematical model of the roll slip is given as a nonlinear differential equation. Then, by using a Taylor series expansion, it is linearized as a state space model. Next, by using Gopinath's algorithm, a minimal-order state observer based on the state space model is designed to estimate the angular speed of all idle rolls except for an actuated roll that is measureable. Finally, a computer simulation is used to validate that the proposed state space model very well describes slip dynamics between, and moreover, the state observer very well estimates the angular speed of the idle roll.

Identification and Multivariable Iterative Learning Control of an RTP Process for Maximum Uniformity of Wafer Temperature

  • Cho, Moon-Ki;Lee, Yong-Hee;Joo, Sang-Rae;Lee, Kwang-S.
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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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.

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The State Space Identification Model of the Dynamic System using Neural Networks (신경회로망을 이용한 동적 시스템의 상태 공간 인식 모델)

  • 이재현;탁환호;이상배
    • Journal of the Korean Institute of Intelligent Systems
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    • v.10 no.5
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    • pp.442-448
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    • 2000
  • The conventional control of dynamic systems needs accurate mathematical modeling of control systems. But the modeling of dynamic systems require very complex computation process due to complex state equation and many control parameters. Accordingly this paper proposes a state space identification model of the dynamic system using neural networks. The Gauss-Newton method is used to train the proposed neural network and the effectiveness of proposed method is verified through the computer simulation of the Seesaw system identification problem.

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Acoustic theory application in ultra short baseline system for tracking AUV

  • Ji, Daxiong;Liu, Jian;Zheng, Rong
    • Ocean Systems Engineering
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    • v.3 no.1
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    • pp.71-77
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    • 2013
  • The effective tracking area of ultra short baseline (USBL) systems strongly relates to the safety of autonomous underwater vehicles (AUVs). This problem has not been studied previously. A method for determining the effective tracking area using acoustic theory is proposed. Ray acoustic equations are used to draw rays which ascertain the effective space. The sonar equation is established in order to discover the available range of the USBL system and the background noise level using sonar characteristics. The available range defines a hemisphere like enclosure. The overlap of the effective space with the hemisphere is the effective area for USBL systems tracking AUVs. Lake and sea trials show the proposed method's validity.

Real Time Estimation in 1-Dimensional Temperature Distribution Using Modal Analysis and Observer (모드해석과 관측기를 이용한 1차원 온도분포의 실시간 예측)

  • An, Jung-Yong;Park, Yeong-Min;Jeong, Seong-Jong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.2
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    • pp.195-201
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    • 2001
  • An inverse heat conduction problem(IHCP) arises when unknown heat fluxes and whole temperature field are to be found with temperature measurements of a few points. In this paper, observers are proposed as solution algorithm for the IHCP. A 1-dimensional heat transfer problem is modeled with modal analysis and state space equations. Position of the heat source is estimated through test heat inputs and the autocorrelation among a few of temperature data. The modified Bass-Gura method is used to design a state observer to estimate the intensity of heat source and the whole temperature field of a 1-dimensional body. To verify the reliability of this estimator, analytic solutions obtained from the proposed method are compared.

Real-time estimation of Temperature Distribution of a Ball Screw System Using Modal Analysis and Observer (모드해석과 관측기에 의한 볼스크류 온도분포의 실시간 예측)

  • 김태훈
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.635-640
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    • 2000
  • Thermal deformation of machine tools can be evaluated from the analysis of the whole temperature field. However, it is extremely inefficient and impossible to acquire the whole temperature field by measuring temperatures of every point. So, a temperature estimator, which can estimate the whole temperature field from the temperatures of just a few points, is required. In this paper, 1-dimensional heat transfer problem is modeled with modal analysis and state space equations. and then state observer is designed to estimate the intensity of heat source and the whole temperature field in real-time. The reliability of this estimator is verified by making a comparison between solutions by the proposed method and the exact solutions of examples. The proposed method is applied to the estimation of temperature distribution in a ball screw system.

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Free vibration of orthotropic functionally graded beams with various end conditions

  • Lu, Chao-Feng;Chen, W.Q.
    • Structural Engineering and Mechanics
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    • v.20 no.4
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    • pp.465-476
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    • 2005
  • Free vibration of orthotropic functionally graded beams, whose material properties can vary arbitrarily along the thickness direction, is investigated based on the two-dimensional theory of elasticity. A hybrid state-space/differential quadrature method is employed along with an approximate laminate model, which allows us to obtain the semi-analytical solution easily. With the introduction of continuity conditions at each fictitious interface and boundary conditions at the top and bottom surfaces, the frequency equation for an inhomogeneous beam is derived. A completely exact solution of an FGM beam with material constants varying in exponential way through the thickness is also presented, which serves a benchmark to verify the present method. Numerical results are performed and discussed.

Declutching control of a point absorber with direct linear electric PTO systems

  • Zhang, Xian-Tao;Yang, Jian-Min;Xiao, Long-Fei
    • Ocean Systems Engineering
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    • v.4 no.1
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    • pp.63-82
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    • 2014
  • Declutching control is applied to a hemispherical wave energy converter with direct linear electric Power-Take-Off systems oscillating in heave direction in both regular and irregular waves. The direct linear Power-Take-Off system can be simplified as a mechanical spring and damper system. Time domain model is applied to dynamics of the hemispherical wave energy converter in both regular and irregular waves. And state space model is used to replace the convolution term in time domain equation of the heave oscillation of the converter due to its inconvenience in analyzing the controlled motion of the converters. The declutching control strategy is conducted by optimal command theory based on Pontryagin's maximum principle to gain the controlled optimum sequence of Power-Take-Off forces. The results show that the wave energy converter with declutching control captures more energy than that without control and the former's amplitude and velocity is relatively larger. However, the amplification ratio of the absorbed power by declutching control is only slightly larger than 1. This may indicate that declutching control method may be inapplicable for oscillating wave energy converters with direct linear Power-Take-Off systems in real random sea state, considering the error of prediction of the wave excitation force.

VSS control of inverted pendulum (도립진자의 가변 구조 제어)

  • 한문섭;이욱열
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10a
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    • pp.54-57
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    • 1988
  • In this thesis, after the inverted pendulum being made, its state equation was established with parameters obtained by the state space approach and its position stabilization control was performed with VSS. The switching function of VSS was obtained from pole placement method and as the result of VSS control was compared with that of optimal regulator control, its robustness was clarified in sliding mode. The position and stabilization control of the inverted pendulum Wstem were acomplished with VSS.

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On The Dynamics And The Demagnetization Effect Of The Amplidyne Generator With Auxiliary Feedback Compensating Winding (상태변수에 의한 회전형전자증폭기의 동특성 해석 및 감자작용효과에 관한 연구)

  • Se Hoon Chang
    • 전기의세계
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    • v.21 no.6
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    • pp.9-16
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    • 1972
  • This work intends to study the machine dynamics in the state-space approah and to formulate the operating characteristics of a namplidyne generator, with balanced control field winding and an auxiliary feedback winding for compensating purpose. In the derivation of the dynamic equation, investigations on the demagnetization effects are accentuated, based on the magnetic interlinks between windings of the machine. From the machine dynamic relation obtained, a state-variable representation of the machine dynamics is approached in the first part of this work.

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