• 한국항공우주학회지
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• 제34권11호
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• pp.35-41
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• 2006

이 논문에서는 항공기의 비행제어에 적용하기 위해 각각의 비행영역에서 설계된 LQ(Linear Quadratic)제어기를 비행영역이 바뀜에도 충돌 없이 교체할 수 있는 알고리즘을 제안한다. 이 알고리즘은 기존의 구현 알고리즘에 비해 LQ제어기에 적용하기 편리하게 유도되었고, 비선형 모델에도 적용할 수 있도록 트림점을 포함한 식으로 제시된다. 제안된 알고리즘의 성능을 확인하기 위해 시험표준 문제로 초음속 시험 항공기의 LQ제어문제에 적용하는 모의실험을 수행하고 제어성능이 우수함을 예시한다.

• 전기학회논문지
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• 제56권4호
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• pp.777-783
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• 2007

In this paper, we present a novel control approach for linear motor-based transfer systems in which friction reduction and enhancement of control performance are considered. In general, in such systems friction effects from rails and wheels, and internal bearings complicate control scheme since in particularly its dynamics are arbitrarily changed due to mass variation, detent force of motor systems, and gaps among stators. Our control approach is achieved to reduce this undesired friction dynamics using fuzzy system. We construct hybrid control approach for this control system which Is composed of a nominal control and a vertical control against friction. Fuzzy parameter vector is optimally determined from iterative simulation experiments. We demonstrate its superiority via numerical simulations comparing with a traditional control method.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권2호
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• pp.147-152
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• 1999

Semiconductor piezoresistive type vibration sensor was fabricated by using semiconductor process and micromachining technology. To measure the micro electromagnetic force between coil and magnet, fabricated vibration sensor was used. Toapply micro electromagnetic force produced from the micro exciter, small-sized NdFeB permanent magnet was attached on the mass of the fabricated vibration sensor. The measured electromagnetic force are about 5~180dyne when the applied sinusoidal current of 1KHz in the range of 1.5~8mA. The measurement of micro electromagnetic forcewas performed by changing the distance between coil and magnet. Output characteristics of micro electromagnetic force according to the applied coil current were linear. Furthermore, output results were used to get the transfer constant that is important to decide the efficiency and the performance of the coil and magnet.

• 설비공학논문집
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• 제15권2호
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• pp.126-131
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• 2003

Convective instability driven by surface tension is analyzed in an initially quiescent water absorbing ammonia gas with heat transfer using the linear stability analysis. The propagation theory is adapted to find the critical conditions of the onset of Marangoni convection. In this theory, the solutal penetration depth is chosen as the length scale factor. The results show that the liquid layer becomes more stable with decreasing the Schmidt number and increasing the Lewis number. It is also found that there is a critical Biot number to make the liquid layer be most unstable, and there is a linear relationship between the thor-mal Marangoni number and the solutal Marangoni number.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.322-322
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• 2006

Well-defined poly(N-vinylcarbazole), poly(NVC), was synthesized by macromolecular design via interchange of the xanthate (MADIX)/reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of a suitable xanthate-type chain transfer agent (CTA). Good control of the polymerization was confirmed by the linear first-order kinetic plot, the molecular weight controlled by the monomer/CTA molar ratio, linear increase in the molecular weight with the conversion, and the ability to extend the chains by the second addition of the monomer. Star polymers having various architectures were also synthesized using this technique.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.204-208
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• 2001

In this paper, we induce the linear transfer function of Downcomer water level of NPP(Nuclear Power Plant) Steam Generator using Genetic Algorithm and Levenberg-Marquardt Algorithm. The characteristic of NPP S/G mechanism is so high-non-linear that it is hard to achieve mathematical expression. So we use non-mathematical Algorithms to get the model function of NPP S/G water level. S/G level controller would be designed with this transfer function as the plant.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.125-128
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• 1999

A linear time-invariant model can be described either by a parametric model or by a nonparametric model. Nonparametric models, for which a priori information is not necessary, are basically the response of the dynamic system such as impulse response model and frequency models. Parametric models, such as transfer function models, can be easily described by a small number of parameters. In this paper aiming to take benefit from both types of models, we will use linear-combination of basis fuctions in an impulse response using a few parameters. We will expand and generalize the Kautz functions as basis functions for dynamical system representations and we will consider estimation problem of transfer functions using Kautz function. And so we will present the influences of poles settings of Kautz function on the identification accuracy.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.556-558
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• 1990

A method of model reduction for reducing a higher order Z-transfer function to its lower order model is developed based on the Block - pulse function. The approach is following : I. Block - pulse function can be applied for Z-transfer function of linear digital system described by high order. II. To determined both the coefficients of the denominator and numerator of reduced model. The proposed method is simple for computation, can preserve the dynamic characteristic of the original model satisfactorily.

• 전기의세계
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• 제23권2호
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• pp.46-54
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• 1974

The purposes of this paper are to deal with the design of m-input, m-output linear systems by the state variable feedback, and to extend the design capability of the state variable feedback design. The design requirements are decoupling and the exact realigation of desired transfer functions. Some methods are proposed to insert series compensators in the fixed plant in the cases when series compensators are needed to meet the input-output transfer matrix specification. The method for adding series compensators to the input channels of the fixed plant is shown by examples to lead both to the loss of the ability to decouple the augmented plant by the state variable feedback, and to the loss of desired zeroes. A method which avoids these two hazards is developed in which series compensators are put on the output channels of the fixed plant: it is proved that the augmented plant is F-invariant. By treating each subsystem individually, the designer can apply some of the previous developed knowledge of the state variable design of single-input, single-output systems.

• 대한기계학회논문집A
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• 제32권10호
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• pp.836-843
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• 2008

An efficient domain/boundary decomposition method is applied for heat transfer problems with non-linear thermal radiation boundaries. The whole domain of solids or structures is considered as set of subdomains, an interface, and radiation interfaces. In a variational formulation, simple penalty functions are introduced to connect an interface or radiation interfaces with neighboring subdomains that satisfy continuity conditions. As a result, non-linear finite element computations due to the thermal radiation boundaries can be localized within a few subdomains or radiation interfaces. Therefore, by setting up suitable solution algorithms for the governing finite element equations, the computational efficiency can be improved considerably. Through a set of numerical examples, these distinguishing characteristics of the present method are investigated in detail.