• 전기학회논문지
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• 제59권2호
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• pp.411-416
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• 2010

In this paper, an integral variable structure static output feedback controller with an integral-augmented sliding surface is designed for the improved robust control of a uncertain system under unmatched system uncertainty and matched input matrix uncertainty and disturbance satisfying some conditions. To effectively remove the reaching phase problems, an output dependent integral augmented sliding surface is proposed. Its equivalent control and ideal sliding mode dynamics are obtained. The previous some limitations is overcome in this systematic design. A stabilizing control with the closed loop exponential stability is designed for all unmatched system matrix uncertainties and proved together with the existence condition of the sliding mode on S=0. To show the usefulness of the algorithm, a design example and computer simulations are presented.

• 한국통신학회논문지
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• 제31권3A호
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• pp.356-359
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• 2006

A monolithic SiGe HBT variable gain driver amplifier(VGDA) with high dB-linear gain control and high linearity has been developed as a driver amplifier with ground-shielded microstrip lines for 5-GHz transmitters. The VGDA consists of three blocks such as the cascode gain-control stage, fixed-gain output stage, and voltage control block. The circuit elements were optimized by using the Agilent Technologies' ADSs. The VGDA was implemented in STMicroelectronics' 0.35${\mu}m$ Si-BiCMOS process. The VGDA exhibits a dynamic gain control range of 34 dB with the control voltage range from 0 to 2.3 V in 5.15-5.35 GHz band. At 5.15 GHz, maximum gain and attenuation are 10.5 dB and -23.6 dB, respectively. The amplifier also produces a 1-dB gain-compression output power of -3 dBm and output third-order intercept point of 7.5 dBm. Input/output voltage standing wave ratios of the VGDA keep low and constant despite change in the gain-control voltage.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권4호
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• pp.177-183
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• 2001

In this paper, a new variable structure controller is designed for the tracker control of uncertain general plants so that the output of plants can controlled to a given arbitrary point in state space. By using the error between the steady state value of the output and the given reference, the sliding surface is defined, in advance, the surface from an initial state to the given reference without any reaching phase. A corresponding control input to satisfy the existence condition of the sliding mode is suggested to control the output on the predefined surface. Therefore the output controlled by the proposed controller is completely robust and identical to that of the sliding surface. Through an example, the usefulness is verified.

• 산업기술연구
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• 제32권A호
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• pp.115-118
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• 2012

Recently, there are a lot of papers in order to replace the electrolytic capacitor into the film capacitor in output of PFC(Power Factor Correction). However, the film capacitor, which has capacitance of low values, causes a large ripple voltage in output of PFC. The LED drivers are connected series in the output of PFC and affected by the magnitude of voltage ripple. In this paper, we have compared the fixed frequency method with the variable frequency for the constant-current control and propose the control method to avoid the sub-harmonic oscillation in the variable input voltage. An 80W PFC, using film capacitors instead of electrolytic capacitors, and LED driver has been built and compared the fixed frequency control method with the variable frequency control method.

• 한국건설관리학회논문집
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• 제13권5호
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• pp.94-102
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• 2012

최근 글로벌 금융위기, 미분양 주택의 증가 등으로 인해 건설기업의 효율성 분석이 요구되고 있다. 기업에 대한 효율성 분석시 가장 중요한 것은 효율성 측정에 사용된 투입-산출변수이다. 하지만 건설기업의 효율성 분석에 중요한 영향을 미치는 핵심적인 투입-산출변수를 추출하기 위한 체계적인 연구는 미흡하였다. 따라서 본 연구에서는 건설기업의 효율성 분석을 위한 핵심 투입-산출변수를 추출을 위해 투입-산출변수 별로 모든 조합을 제시한 모형을 제시하고 DEA모형과 PCA분석을 통하여 건설기업의 효율성을 분석에 중요한 요소인 투입-산출변수를 추출하고자 한다. 본 연구를 위해 기존 연구 및 이론적 고찰을 하고, 효율성 측정을 위한 변수 및 21개 모형을 설정하였다. 다음으로 효율성 및 PCA분석을 하고 결과를 도출하였다. 연구 결과, 핵심적인 투입 및 산출변수는 2006년의 경우 투입변수는 종업원수, 산출변수는 매출액, 2008년의 경우 투입변수는 자본금, 산출변수는 당기순이익, 2010년의 경우 투입변수는 고정자산, 산출변수는 매출액으로 나타났다. 건설기업 효율성 결과에 중요한 영향을 주는 변수 추출을 통해 개별 건설기업들이 효율성을 향상하기 위한 중점전략을 마련할 수 있을 것으로 판단된다.

• Journal of the Korean Data and Information Science Society
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• 제22권4호
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• pp.679-690
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• 2011

통계적 공정관리 (statistical process control; SPC)와 자동공정관리 (automatic process control; APC)는 공정의 품질을 향상시키기 위하여 가장 널리 사용하는 방법이다. 이 두 종류의 관리절차는 서로 독립적으로 적용되고 연구되어져 왔지만, 현대의 생산 공정은 공정 자체가 복잡하고 혼합된 양상을 나타내기 때문에 두 관리절차를 병행하여 사용함으로써 관리효과를 증대시킬 수 있게 된다. 이와 같이 수정과 탐지를 동시에 사용하여 공정을 좀 더 효율적으로 관리하고자 하는 절차를 통합 공정관리 (integrated process control; IPC)라고 한다. IPC의 기본절차는 잡음이 내재하는 공정에 대하여 수정조치를 취하고, 이러한 수정활동 중 공정에 이상원인이 발생했는지 관리도를 통하여 이를 탐지하는 것이다. APC로 조정된 공정을 관리할 경우 일반적으로 출력변수를 관리통계량으로 사용하고 있으나, 입력변수를 관리통계량으로 사용하는 연구 결과들도 있다. 이 논문에서는 누적이동평균(integrated moving average; IMA) (1,1) 잡음모형과 최소평균제곱오차 (minimum mean square error; MMSE) 수정을 가정할 경우, 출력변수, 입력변수, 그리고 출력변수와 입력변수의 정보를 모두 이용하는, 즉 출력과 입력변수의 차이변수를 사용하는 절차의 효율을 비교하고 있다.

• 전기학회논문지
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• 제59권7호
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• pp.1289-1294
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• 2010

In this paper, a new discrete integral static output feedback variable structure controller based on the a new integral dynamic-type sliding surface and output feedback discrete version of the disturbance observer is suggested for the control of uncertain linear systems. The reaching phase is completely removed by introducing a new proposed integral dynamic-type sliding surface. The output feedback discrete version of disturbance observer is presented for effective compensation of uncertainties and disturbance. A corresponding control with disturbance compensation is selected to guarantee the quasi sliding mode on the predetermined integral dynamic-type sliding surface for guaranteeing the designed output in the integral dynamic-type sliding surface from any initial condition for all the parameter variations and disturbances. Using discrete Lyapunov function, the closed loop stability and the existence condition of the quasi sliding mode is proved. Finally, an illustrative example is presented to show the effectiveness of the algorithm.

• 대한기계학회논문집B
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• 제25권9호
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• pp.1202-1202
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• 2001

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.1066-1071
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• 1992

A new scheme of OFVSC(Output Feedvack Variable Structure Controller) is proposed for the servo control system. The main structure of proposed control scheme is composed of servo compensator and dynamic switiching function. By the use of dynamic switiching function the assumption of full state availability can be removed and the disturbances which does not satisfy the matching condition cna be rejected. And the servo compensator which is designed for each output variable the robustness for the all type of disturbances. And the performances of proposed control system are evaluated through simulation studies for a numerical example.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.232-237
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• 1991

Digital Variable Structure Controller(DVSC) is proposed to control variable speed recirculating pump for hot-water heating control system. In this study, nonlinear sliding line is used beyond output error boundary layer and PID sliding line is used within the layer. For long dead time compensation, constraint is added to Smith predictor algorithm. Steady state error is eliminated by using the proposed sliding line in spite of heating load change. By decreasing sampling time, good sliding motion is yielded but system output noise bv flow dynamics is amplified.