• 한국지진공학회논문집
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• 제10권2호
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• pp.21-29
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• 2006

자유도 수가 많은 고층 구조물의 해석하기 위해 모든 층에 sensors를 설치하는 것은 비 실용적이다. 따라서 이러한 문제를 해결하기 위해 "reduced-order control" 방법이 소개되었다. 본 논문은 동적압축법(dynamic condensation method)이 제안되었다. 이 압축법은 반복법으로 "Guyan condensation"의 initial approximation을 적용하였다. 본 논문에서 제시된 동적압축법(dynamic condensation)은 원하는 값을 얻을 때까지 지속적으로 updated가 되며, 결과는 기존의 "Guyan condensation"보다 정확한 결과를 나타내었다. 또한 "eigenvalue shifting technique"을 적용하여 iteration으로 계산되는 시간을 크게 단축하였다. "Reduced-order system"을 도입하기 위한 두가지 schemes이 토의되었다. 제시된 동적압축법 효과의 증명을 위해 능동 동조질량감쇠 고층빌딩의 수치 해석이 토의되었고, 단지 두 번의 반복(iterations)을 통한 결과는 매우 정확한 것으로 나타났다.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1296-1309
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• 2024

The aim of this work is to explore the effect of the double subdiffusion on the stability in BWRs. A BWR novel reduced order model with double subdiffusion effects: reduced order fractional model (DS-F-ROM) to describe the neutron and heat transfer processes was proposed for this study. The double subdiffusion was developed with a fractional-order two-equation model, and with different fractional-orders and relaxation times. The stability analysis was carried out using the root-locus method and change from the s to the W domain and were confirmed using the time-domain evolution of neutron flux for a unit step change in reactivity. The results obtained using the reduced fractional-order model are presented for different anomalous diffusion coefficient values. Results are compared with normal diffusion and P1 equations, which are obtained straightforwardly with DS-ROM when relaxation time tends to zero, and when the anomalous diffusion coefficient tends to one, respectively.

• 대한기계학회논문집
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• 제11권6호
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• pp.1036-1043
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• 1987

본 연구에서는 유압 서어보 시스템을 유압 피스톤의 변위와 속도를 상태변수 로 하는 2차 선형 시스템으로 모델링하여 변위는 측정된 출력으로부터 직접 구하고 속 도는 B. Gopinath 와 D.G. Cumming에 의해 발전된 축소차수 관측기(Reduced-order Ob- server)를 사용하여 추정하며 이를 피이드백 제어에 이용하였다.

• 전기학회논문지
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• 제66권5호
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• pp.812-818
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• 2017

In this paper, we design a reduced-order disturbance observer (DOB) controller for an EMS (Electro-Magnetic Suspension) system with mass uncertainty. Compared with conventional DOB controller, the proposed reduced-order DOB controller can be implemented in a simpler way, since it uses reduced order nominal model and Q-filter. It is shown that the nominal model for the proposed DOB controller should be carefully chosen in order to achieve the robust stability in the present of mass uncertainty. Computer simulation results to validate the effectiveness of the proposed DOB controller are included.

• 대한전자공학회논문지
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• 제24권6호
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• pp.948-955
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• 1987

The model reduction method of the high order linear time invariant systems is proposed. The continuous fraction expansion of Auxiliary denominator polynomial is used to obtain denominator polynomial of the reduced order model, and the numerator polynomial of the reduced order model is obtained by equating the first some moments of the original and the reduced order model, using simplified moment function. This methiod does not require the calculation of the reciprocal transformation which should be calculated in Routh approximation, furthemore the stability of the reduced order model is guaranted if original system is stable. Responses of this method showed us good characteristics.

• 전자공학회논문지S
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• 제34S권9호
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• pp.50-59
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• 1997

This paper is on the generalized singular perturbation approximation (GSPA) preserving the discrete positive real property. We transform the discrete positive real(PR) system into a stochastically banlanced system and get the reduced order discrete system from the GSPA of the full order stochastically balanced system. eSPECIALLY, WHEN THE FREE PARAMETER OF THE gspa IS .+-.1, we show that the reduced order discrete system retains stability, minimality, and positive real and stochstically balancing properties. And we derived the .inf.-norm error bound with the reduced order discrete strictly positive real(SPR) system by the proposed method. Finally, we give an example to ascertain the properties of the proposed reduced order discrete system and to compare with the conventional methods.

• Structural Engineering and Mechanics
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• 제78권3호
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• pp.305-317
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• 2021

An AMD control system is usually built based on the original model of a target building. As a result, the fact leads a large calculation workload exists. Therefore, the orders of a structural model should be reduced appropriately. Among various model-reduction methods, a suitable reduced-order model is important to high-rise buildings. Meanwhile, a partial structural information is discarded directly in the model-reduction process, which leads to the accuracy reduction of its controller design. In this paper, an optimal technique is selected through comparing several common model-reduction methods. Then, considering the dynamic characteristics of a high-rise building, an improved balanced truncation (BT) method is proposed for establishing its reduced-order model. The abandoned structural information, including natural frequencies, damping ratios and modal information of the original model, is reconsidered. Based on the improved reduced-order model, a new reduced-order controller is designed by a regional pole-placement method. A high-rise building with an AMD system is regarded as an example, in which the energy distribution, the control effects and the control parameters are used as the indexes to analyze the performance of the improved reduced-order controller. To verify its effectiveness, the proposed methodology is also applied to a four-storey experimental frame. The results demonstrate that the new controller has a stable control performance and a relatively short calculation time, which provides good potential for structural vibration control of high-rise buildings.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.52-55
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• 1996

In this paper, we consider the decentralized reduced-order H$_{\infty}$ controller for the general plant. Simplifying method is suggested for the general plant with the decentralized controller structure. When the controller is reconstructed for the original system, the decentralizability of the controller for the transformed system is generally destroyed with the older method. We solve this problem. For the simplified system, the structure of the decentralized controller is suggested..

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.177-181
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• 1997

In the speed control system of motors using the low resolution rotary encoder, the period of encoder pulse becomes longer than the sampling time for speed control in the range of very low speed. Therefore, it is difficult to obtain accurate speed information. In this paper, the speed estimating method at the very low speed region using reduced order torque observer, which has been widely used, is examined. The results of simulation show that the characteristics of the speed control at the very low speed region is improved by using the reduced order torque observer.

• 제어로봇시스템학회논문지
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• 제14권8호
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• pp.837-841
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• 2008

This paper presents a robust reduced order state observer for a class of Lipschitz nonlinear systems with external disturbance. Sufficient conditions on the existence of the proposed observer are characterized by linear matrix inequalities. It is also shown that the proposed observer design can reduce the effect on the estimation error of external disturbance up to the prescribed level. Finally, a numerical example is provided to verify the proposed design method.