• 전기의세계
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• 제28권5호
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• pp.44-48
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• 1979

For ordinary systems the receding horizon method has beer proved by the author as a very useful and easy tool to find stable feedback controls. In this paper an open-loop optimal control which minimizes the control energy with a suitable upper limit and terminal control and state constraints is derived and then transformed to the closed-loop control. The stable feedback control law is obtained from the closed-loop control. The stable feedback control law is obtained from the closed-loop control by the receding horizon concept. It is shown by the Lyapunov method that the control law derived from the receding, horizon concept is asymtotically stable under the complete controllability condition. The stable feedback control which is similar to but more general than the receding horizon control is presented in this paper To the author's knowledge the control laws in this paper are easiest to stabilize systems with delay in control.

• International Journal of Aeronautical and Space Sciences
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• 제15권1호
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• pp.74-81
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• 2014

This article documents the design of a novel two-loop acceleration autopilot based on $\mathcal{L}_1$ adaptive output feedback control for tail-controlled missiles. The inner loop is an adaptive angle-of-attack tracking loop and the outer loop is the traditional PI controller for error compensation. A systematic low-pass filter design procedure is provided for minimum phase system and is applied to the inner loop design while the parameters of the outer loop are obtained from the multi-objective optimization problem. The effectiveness of the proposed autopilot is verified through numerical simulations under various conditions.

• 대한전자공학회논문지
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• 제17권6호
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• pp.72-77
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• 1980

본 논문에서는 optical feedback prebias control 회로상의 몇가지 일반적인 문제점들을 분석하고 이에 수반되는 회로 조정의 문제를 해결하기 위하여 LD simulation 회로를 제시하였다. 온도 시험에서 LD의 총 light power를 feedback loop에 사용하였을 때 0℃부터 36℃까지의 사이에서 1.5%의 light power 감소를 보였고 star coupler를 beam splitter로 1%정도를 분지, feedback loop에 사용한 결과 transmitter로서 좋은 전송 특성을 가짐을 관찰하였다.

• 한국정보전자통신기술학회논문지
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• 제15권2호
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• pp.89-94
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• 2022

본 논문에서 주파수변동전환회로(FFCC : Frequency Fluctuation Converting Circuit)를 가진 이산시간 루프 필터(DLF) 위상고정루프(Phase Locked Loop: PLL)를 제안하였다. 이산시간 루프 필터는 기존의 연속 시간 루프 필터와 달리 전하펌프와 전압발진기가 이산적으로 연결하여 스퍼 특성을 개선할 수 있다. 제안된 위상고정루프의 주파수변동 전환회로가 포함된 내부 부궤환 루프는 이산 시간 루프 필터의 외부 부궤환 루프를 안정하게 동작하도록 해준다. 부궤환 루프 역할을 하는 주파수변동전환회로를 통해 루프 필터 출력 전압 변위 크기를 줄여 잡음특성을 더욱 개선하였다. 그리하여 기존 구조보다 지터 크기를 1/3으로 줄였다. 제안된 위상고정루프는 1.8V 180nm CMOS 공정을 이용하여 Hspice로 시뮬레이션하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1706-1710
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• 2004

This paper presents a feedback-controlled, MEMS-fabricated microaccelerometer (${\mu}$XL). The ${\mu}$XL has received much commercial attraction, but its performance is generally limited. To improve the open-loop performance, a feedback controller is designed and experimentally evaluated. The feedback controller is applied to the x/y-axis ${\mu}$XL fabricated by sacrificial bulk micromachining (SBM) process. Even though the resolution of the closed-loop system is slightly worse than open-loop system, the bandwidth, linearity, and bias stability are significantly improved. The noise equivalent resolution of open-loop system is 0.615 mg and that of closed-loop system is 0.864 mg. The bandwidths of open-loop and closed-loop system are over 100 Hz. The input range, non-linearity and bias stability are improved from ${\pm}$10 g to ${\pm}$18 g, from 11.1 %FSO to 0.86 %FSO, and from 0.221 mg to 0.128 mg by feedback control, respectively

• East Asian mathematical journal
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• 제36권3호
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• pp.365-376
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• 2020

Nonalcoholic fatty liver is a type of fatty liver in which fat accumulates in the liver without alcohol. In the accumulation, Nrf1 and miR-378 genes play very important role, so called negative feedback loop, in which the two genes suppress the other's production. In other words, Nrf1 activates fatty acid oxidation which promotes fat consumption in the liver, while miR-378 deactivates fatty acid oxidation. Thus, both genes regulate nonalcoholic fatty liver. In this paper, the negative feedback loop of Nrf1 and miR-378 are expressed by a system of ordinary differential equations. And, bifurcation simulation shows the change in the amount of each gene with significant parameter range changes. Bifurcation simulation has also used to determine the thresholds for transit between disease and steady state.

• 조명전기설비학회논문지
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• 제26권5호
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• pp.71-78
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• 2012

This paper presents a digital control solution to process capacitor current feedback of high performance single-phase UPS for non-linear loads. In all UPS the goal is to maintain the desired output voltage waveform and RMS value over all unknown load conditions and transient response. The proposed UPS uses instantaneous load voltage and filter capacitor current feedback, which is based on the double regulation loop such as the outer voltage control loop and inner current control loop. The proposed DSP-based digital-controlled PWM inverter system has fast dynamic response and low total harmonic distortion (THD) for nonlinear load. The control system was implemented on a 32bit Floating-point DSP controller TMS320C32 and tested on a 5[KVA] IGBT based inverter switching at 11[Khz]. The validity of the proposed scheme is investigated through simulation and experimental results.

• 한국정보전자통신기술학회논문지
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• 제14권6호
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• pp.479-486
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• 2021

본 논문에서는 신호감지회로(Signal Sensing Circuit : SSC)를 추가하여 2개의 루프로 구성된 단일 커패시터 루프필터를 가진 극소형 위상고정루프(Phase Locked Loop : PLL)를 제안하였다. 위상고정루프 크기를 극단적으로 줄이기 위하여 가장 많은 면적을 차지하는 수동소자 루프필터를 극소형 단일 커패시터(2pF)로 설계하였다. 신호감지회로가 포함된 내부 부궤환 루프 출력이 외부 부궤환 루프의 단일 커패시터 루프필터 출력에 부궤환 역할을 하여 제안한 극소형 위상고정루프가 안정적으로 동작하도록 설계하였다. 위상고정루프 출력 신호 변화를 감지하는 신호 감지 회로는 루프필터의 커패시턴스 전하량을 조절하여 위상고정루프 출력 주파수의 초과 위상변이를 줄였다. 제안된 구조는 기존 구조에 비해 1/78 정도의 작은 커패시터를 가짐에도 불구하고 지터 크기는 10% 정도 차이가 난다. 본 논문의 위상고정루프는 1.8V 180nm 공정을 사용하였고, Spice를 통해 안정하게 동작하는 시뮬레이션 결과를 보여주었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2712-2714
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• 1999

The small signal model for input series-output parallel connected converter system employing charge control together with input capacitor voltage feedback loop is developed. From the model developed, the effect of input capacitor voltage feedback loop to the system stability and outer loop compensator design is analyzed. Theoretical results and simulation show that input capacitor voltage feedback loop has no critical effects on the system stability, so the system can be reduced to a equivalent single module for the stability analysis and outer loop compensator design.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.39.3-39
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• 2002

In this paper, presented is a feedback control loop, for an in-plane gimbaled micro gyroscope based on methodology and state weighted model reduction technique. The micro gyroscope is the basic inertial sensors. To improve the performances such as stability, wide dynamic range, bandwidth and especially robustness, it is necessary to design a feedback control loop, which must be robust, because the manufacturing process errors can be large. Especially, to obtain wide bandwidth, the feedback controller is indispensable, because the gyroscope is high Q factor system and has small open loop bandwidth. Moreover, the feedback controller reduces the effect...