• Title/Summary/Keyword: State equation

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The Control of Flexible Beam using Nonlinear Compensator with Dual-Input Describing Function (쌍입력 기술함수를 갖는 비선형 보상기를 이용한 유연한 빔의 제어)

  • 권세현;이형기;최부귀
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.5
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    • pp.644-650
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    • 1998
  • In this paper , a state space model for flexible beam is presented using the assumed-modes approach. The state space equation is derived for a flexible beam in which one end is connected to a motor and is driven by a torque equation and the other end is free. Many of the transfer function proposed thus far use the torque to the flexible beam as the input and the tip deflection of the flexible beam as the output. The Technique for the analysis and synthesis of the dual-input describing function(DIDF) is introduced here and the construction of a non-linear compensator, based on this technique, is proposed. This non-linear compensator, properly connected in the direct path of a closed-loop linear or non-linear control system. The above non-linear network is used to compensate linear and non-linear systems for instability, limit cycles, low speed of response and static accuracy. The effectiveness of the proposed scheme is demonstrated through computer simulation and experimental results.

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The Discrete-Time $H_2$/$H_{\infty}$ Control Synthesis : State Feedback Case

  • Bambang, Riyanto;Shimemura, Etsujiro;Uchida, Kenko
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10b
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    • pp.858-863
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    • 1990
  • A synthesis of feedback control-law with combined H$_{2}$/H$_{\infty}$ perfoemance criteria is proposed for discrete-time systems, under the assumption that the state is available for feedback. An auxiliary minimization problem is defined to enforce the H$_{\infty}$ disturbance attenuation constrain while minimizing the H$_{2}$ performance bound. The design equation is presented in terms of a modified Riccati equation which leads to the standard LQ solution when the H$_{\infty}$ constraint is completely relaxed. The results of the paper clarity the correspondences between H$_{2}$/H$_{\infty}$ results in discrete-time systems and their continuous-time counter-parts.rts.

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SDRE Based Near Optimal Controller Design of Permanent Magnet Synchronous Generator for Variable-Speed Wind Turbine System (가변속 풍력 발전용 영구자석형 동기발전기의 SDRE 기반 준최적 비선형 제어기 설계)

  • Park, Hyung-Moo;Choi, Han Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.1
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    • pp.28-33
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    • 2015
  • In this paper, we propose a near optimal controller design method for permanent magnet synchronous generators (PMSGs) of MW-class direct-driven wind turbine systems based on SDRE (State Dependent Riccati Equation) approach. Using the solution matrix of an SDRE, we parameterize the optimal controller gain. We present a simple algorithm to compute the near optimal controller gain. The proposed optimal controller can enable PMSGs to precisely track the reference speed determined by the MPPT algorithm. Finally, numerical simulation results are given to verify the effectiveness of the proposed optimal controller.

A M-TYPE RISK MODEL WITH MARKOV-MODULATED PREMIUM RATE

  • Yu, Wen-Guang
    • Journal of applied mathematics & informatics
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    • v.27 no.5_6
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    • pp.1033-1047
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    • 2009
  • In this paper, we consider a m-type risk model with Markov-modulated premium rate. A integral equation for the conditional ruin probability is obtained. A recursive inequality for the ruin probability with the stationary initial distribution and the upper bound for the ruin probability with no initial reserve are given. A system of Laplace transforms of non-ruin probabilities, given the initial environment state, is established from a system of integro-differential equations. In the two-state model, explicit formulas for non-ruin probabilities are obtained when the initial reserve is zero or when both claim size distributions belong to the $K_n$-family, n $\in$ $N^+$ One example is given with claim sizes that have exponential distributions.

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The Interaction Potential Functions in an Electrolyte Protein Solution

  • Jee, Nam-Yong;Kim, Jae-Jun
    • Macromolecular Research
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    • v.14 no.6
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    • pp.654-658
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    • 2006
  • Recent developments in equations of state for molecular fluids have demonstrated the feasibility of using the hard-sphere equation to describe the effects of repulsive forces in simple fluids. By including a suitable term for attractive forces, most conveniently a uniform background potential, the properties of bio-macromolecular interaction can be roughly calculated. However, the choice of the potential used in perturbed hard-sphere chain (PHSC) theory for describing the attractions between macromolecules is rather complicated. For hard-sphere chains, the prediction accuracy from each model strongly depends on the choice of potential function.

Deformation Analysis of Self-regulating Bellows in Joule-Thomson Cryocooler (줄-톰슨 극저온 냉각기용 벨로우즈의 변형해석)

  • Lee, Sang-Eun;Lee, Tae-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.4
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    • pp.100-107
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    • 2008
  • Bellows is an important component in Joule-Thomson cryocooler, which minimize the excessive flow of the cryogenic gas. The bellows is made of Monel 400 and its geometry is an axial symmetric shell. During cool-down process, the pressure and volume within bellows must be satisfied with Benedict-Webb-Rubin state equation. Moreover, Poisson's ratio of Monel 400 is nearly constants, but its Young's modulus varies for a drop in temperature. Under these conditions, bellows contracts in the axial direction like a spring. To evaluate deformation of bellows at cryogenic temperature, the numerical calculation of the volume within bellows and finite element analysis are iteratively used in this research. the numerical results show that deformation of the bellows is approximately linear for change of temperature.

Thermodynamic Model for Partition Coefficients in the Two Protein Systems

  • Jung, Chang-Min;Bae, Young-Chan;Kim, Jae-Jun
    • Macromolecular Research
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    • v.15 no.7
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    • pp.682-687
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    • 2007
  • The equation of state developed herein is predicated on a hard-sphere reference with perturbations introduced via a potential function to account for electrostatic forces and for attraction between protein particles. During this process, the generalized Lennard-Jones (GLJ) pair potential function is employed. The GLJ pair potential function is employed to represent the protein-protein interaction in two-protein systems. Via the use of the relation between the equation of state and the chemical potential, the phase behavior in the aqueous two-protein system can be estimated. The partition coefficients can be obtained via these processes. The calculated values of the coefficients agree fairly well with the experimental data in the given pH and ionic strength range, with no additional adjustable model parameters.

Mixing Characteristics of Kerosene-Lox in a Swirl Injector at 100 bar

  • Heo, Junyoung;Kang, Jeongseok;Sung, Hong-Gye
    • International Journal of Aerospace System Engineering
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    • v.3 no.1
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    • pp.30-38
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    • 2016
  • The The turbulent mixing characteristics of Kerosene-LOx in a coaxial swirl injector 100 bar have been numerically investigated. Turbulent model is based on large eddy simulation with real-fluid transport and thermodynamics. The effects of equation of state (EOS), chamber pressure are evaluated in a point of the mixing efficiency and pressure fluctuations. The dominant frequency is same as the hairpin vortex shedding frequency generated by film wave at the LOx post.

Symmetric Conformal Mapping for Surface Matching and Registration

  • Zeng, Wei;Hua, Jing;Gu, Xianfeng David
    • International Journal of CAD/CAM
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    • v.9 no.1
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    • pp.103-109
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    • 2010
  • Recently, various conformal geometric methods have been presented for non-rigid surface matching and registration. This work proposes to improve the robustness of conformal geometric methods to the boundaries by incorporating the symmetric information of the input surface. We presented two symmetric conformal mapping methods, which are based on solving Riemann-Cauchy equation and curvature flow respectively. Experimental results on geometric data acquired from real life demonstrate that the symmetric conformal mapping is insensitive to the boundary occlusions. The method outperforms all the others in terms of robustness. The method has the potential to be generalized to high genus surfaces using hyperbolic curvature flow.

Robust Adaptive Observer Design for a Class of Nonlinear Systems via an Optimization Method (최적화 기법에 의한 비선형 시스템에서의 강인한 적응 관측기 설계)

  • Jung Jong-Chul;Huh Kun-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.10 s.253
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    • pp.1249-1254
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    • 2006
  • Existing adaptive observers may cause the parameter drifts due to disturbances even if state estimation errors remain small. To avoid the drift phenomena in the presence of bounded disturbances, several robust adaptive observers have been introduced addressing bounds in state and parameter estimates. However, it is not easy for these observers to manipulate the size of the bounds with the selection of the observer gain. In order to reduce estimation errors, this paper introduces the (equation omitted) gain minimization problem in the adaptive observer structure, which minimizes the (equation omitted) gain between disturbances and estimation errors. The stability condition of the adaptive observer is reformulated as a linear matrix inequality, and the observer gain is optimally chosen by solving the convex optimization problem. The estimation performance is demonstrated through a numerical example.