• 제어로봇시스템학회논문지
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• 제16권2호
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• pp.134-139
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• 2010

In order to overcome some problems of existing anti-windup methods, this paper defines LQ (Linear Quadratic) observer and proposes a new anti-windup method using the LQ observer. LQ observer is derived by linear quadratic optimization in order to calculate controller states, which make the controller outputs equal to the plant inputs. And we propose an algorithm so that it can be implemented by a digital controller easily. The relationship between the design parameters and the anti-windup performance is shown via some numerical examples, which cover the cases with the anti-windup method using LQ observer designed and the case without it. Finally, the anti-windup performance of the proposed method is exemplified via comparison with the existing model-based conditioning scheme method[4].

• 한국방사선학회논문지
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• 제9권6호
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• pp.417-420
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• 2015

본 연구는 탄소 빔의 분할조사 후 세포생존율 (Surviving Fraction, SF) 값에 따른 Linear-Quadratic model, Incomplete Repair model, Marchese model의 결과값을 비교하기 위해 진행하였다. 탄소 빔을 4fraction까지 조사한 후 얻은 세포생존율 값을 바탕으로 mathematica 프로그램 (ver 9.0)을 이용하여 각각의 모델로 결과값을 얻어 비교해 보았다. 그 결과 즉시 NB1RGB를 시딩한 값은 repair가 감안되지 않은 LQ 모델이 적합하였지만 fraction 시행한 후의 결과값은 오차를 보였다. 따라서 Potentially Lethal Damage Repair (PLDR)과 Sublethal Damage Repair (SLDR)의 발생을 각각 감안한 repair 모델을 이용하여 적합한지 판단하였다. 이를 바탕으로 탄소 빔의 분할 조사 시 LQ 모델에 각각의 repair의 양을 감안한 새로운 회복 관련 모델의 적용 가능성을 보고자 하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.884-889
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• 1989

In this paper, a new procedure for selecting weighting matrices in linear discrete time quadratic optimal control problem (LQ-problem) is proposed. In LQ-problems, the quadratic weighting matrices are usually decided on trial and error in order to get a good response. But using the proposed method, the quadratic weights are decided in such a way that all poles of the closed loop system are located in a desired region for good responses as well as for stability and values of the quadratic cost function are kept less then a specified value.

• 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.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.729-733
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• 1988

In this paper, a new procedure for selecting weighting matrices in linear discrete time quadratic optimal control problems (LQ-problem) is proposed. In LQ problems, the quadratic weighting matrices are usually decided on trial and error in order to get a good response. But using the proposed method, the quadratic weights are decided in such a way that all poles of the closed loop system are located in a desired area for good responses as well as for stability and values of the quadratic cost functional are kept less then a specified value. The closed loop systems constructed by this method have merits of LQ problems as well as those of pole assignment problems. Taking into consideration that little is known about the relationship among the quadratic weights, the poles and the values of cost functional, this procedure is also interesting from the theoretical point of view.

• 제어로봇시스템학회논문지
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• 제13권11호
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• pp.1048-1052
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• 2007

This paper presents a rank-constrained linear matrix inequality(LMI) approach to simultaneous linear-quadratic(LQ) optimal control by static output feedback. Simultaneous LQ optimal control is formulated as an LMI optimization problem with a nonconvex rank condition. An iterative penalty method recently developed is applied to solve this rank-constrained LMI optimization problem. Numerical experiments are performed to illustrate the proposed method, and the results are compared with those of previous work.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.140-145
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• 2001

Various control algorithms are available to suppress the vibration of a system subjected to disturbances. LQ algorithm is simple and easy to implement the hardwares, but it lacks robustness for uncertainties and often causes difficulty in determining the weighting matrices. This study focuses on the effectiveness ILQ(Inverse Linear Quadratic optimal control) algorithm as the alternative to LQ applied to control the vibration of a building under the seismic excitation. The building is of moment resisting steel frames and assumed to behave within the elastic range. The brief overview of LQ and ILQ algorithms is introduced, and the displacement responses of the structure using ILQ algorithm are compared with those obtained from LQ control. The magnitude of control forces are also determined and compared for both LQ and ILQ algorithm.

• Journal of Communications and Networks
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• 제16권5호
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• pp.485-492
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• 2014

Spectrum sensing for cognitive-radio applications may use a matched-filter detector (in the presence of full knowledge of the signal that may be transmitted by the primary user) or an energy detector (when that knowledge is missing). An intermediate situation occurs when the primary signal is imperfectly known, in which case we advocate the use of a linear-quadratic detector. We show how this detector can be designed by maximizing its deflection, and, using moment-bound theory, we examine its robustness to the variations of the actual probability distribution of the inaccurately known primary signal.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.907-912
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• 1989

A new procedure is presented for optimally placing closed-loop poles of multivariable continuous-time systems in specified regions via linear-quadratic(LQ) state-feedback design. This method has the advantages of pole-placement and LQ-design. In addition, it provides minimum feedback gains in the control law.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.57-60
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• 1999

An optimal control technique designed for simultaneous tracking and quality control for batch processes. The proposed technique is designed by transforming quadratic-criterion based iterative learning control(Q-ILC) into linear quadratic control problem. For real-time quality inferential control, the quality is modeled by linear combination of control input around target qualify and then the relationship between quality and control input can be transformed into time-varying linear state space model. With this state space model, the real-time quality inferential control can be incorporated to LQ control Problem. As a consequence, both the quality variable as well as other controlled variables can progressively reduce their control error as the batch number increases while rejecting real-time disturbances, and finally reach the best achievable states dictated by a quadratic criterion even in case that there is significant model error Also the computational burden is much reduced since the most computation is calculated in off-line. The Proposed control technique is applied to a semi-batch reactor model where series-parallelreactions take place.