• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.4
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• pp.748-755
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• 2001

This paper concerns rotor vibration reduction using magnetic damper system. The fuzzy control logic is utilized to fulfill desired motion. The fuzzy system structure and membership function were first determined by simulation results. The researched control logic contains two fuzzy controller : reference position variation according to the rotor whirling status and error compensation algorithm to minimize the rotor vibration due to unbalance and unstable fluid film force. The Sugeno type output membership function was utilized by several trials and optimized membership function constants were selected from experiments. The experimental results show that the proposed method effectively control and reduce the rotor vibration with fluid film bearings.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.5
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• pp.624-629
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• 1998

Evolutionary computation techniques can solve search problems using simulated evolution based on the ‘survival of the fittest’. Recently, the genetic programming (GP) which evolves computer programs using the genetic algorithm was introduced. In this paper, the genetic programming technique is used in order to design a rule based controller consisting of condition-action rules for an unknown system. No a priori knowledge about the structure of the controller is needed. Representation of a solution, functions and terminals in GP are analyzed, and a method of constructing a fuzzy logic controller using the obtained rule based controller is described. A simulation example using a nonlinear system shows the validity and efficiency of the proposed method.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.118-126
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• 2010

The automated mechanical transmission(AMT) is composed of electronic control management(ECM) and automatic shift gear(ASG). The AMT has advantages which are high efficiency of manual transmissions(MT) and offer operation convenience similar to automatic transmissions(AT). However, it has defects that are the torque gap during gear shift transients and shift time is long. To reduce such defects, it is necessary practically to evaluate error and characteristics as developing simulation model before the control algorithm is applied. In this paper, models are composed of vehicle model and AMT shift control model. Particularly AMT shift control model consists of main clutch management model (MCM) and shift control management model(SCM). The developed models were verified by comparing the simulated and experimental results under the same operational conditions. It can also be used to evaluate shift algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.708-713
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• 2000

A research on the AFC(Auto Feedrate Control) by a fuzzy controller using a tool dynamometer and motor currents was conducted. For simulations, cutting dynamics of end-milling process was modeled by geometric relationship between tool and work-piece. The fuzzy logic controller was employed to track the desired cutting force and showed good performance in simulations and several experiments. The spindle motor currents was modeled to estimate cutting force and successfully used for the AFC.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.469-473
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• 2005

Capacities of a tandom-type air-conditioner may be modulated by turning on/off multiple compressors and adjusting positions of a electronic expansion valve. In this study. control algorithms for compressors and a electronic expansion valve were developed by using fuzzy’ logics. There algorithms were implemented in a test lab and proved to be effective for the control of indoor air temperature and superheat temperature.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1468-1474
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• 2001

In this paper, a new fuzzy-logic anti-swing control scheme is proposed for a three-dimensional overhead crane. The proposed control consists of a position servo control and a fuzzy-logic control. The position servo control is used to control the trolley position and rope length, and the fuzzy-logic control is used to suppress load swing. The proposed control guarantees not only prompt suppression of load swing but also accurate control of trolley position and rope length for the simultaneous travel, traverse, and hoisting motions of the crane. The effectiveness of the proposed control is shown by experiments with a prototype three-dimensional overhead crane.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.45.4-45.4
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• 2009

저궤도 위성에 사용된 반작용휠을 이용한 자세제어 로직의 임무기간 동안의 성능 변화 양상을 분석하였다. 분석에 사용한 저궤도 위성은 임무기간 3년에 고도 685km의 태양 동기 궤도이며 자세제어 센서로 별 추적기 2개를 사용하였고, 구동기로 반작용 휠 4개를 사용하였다. 시간에 따른 성능 감소 경향성을 분석하기 위해 2006년 8월부터 2009년 9월까지 원격측정 데이터를 분석하여 반작용휠을 이용한 자세제어기의 기동시의 기동각에 따른 수렴시간 분석을 수행하였다. 임무 초기에 수행한 기동 수렴시각과 임무 종료 시점 근처에서 수행한 기동 수렴 시각을 비교한 결과 여전히 초기와 유사한 성능을 보이고 있음을 확인하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.8
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• pp.609-615
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• 2002

An application of a simple and effective learning control scheme to a robotic arm for exercise is presented. During exercises, the force applied by a .user to an exercise machine varies for different users and for different workouts of the same user. learning control is used to compensate for the difference between the actual force and the planned one. It is shown through simulation that the learning control method decreases tracking error quickly for both time-invariant and time-varying forcing functions.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.307-308
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• 2013

기존 LED(Light Emitting Diode) 백라이트 LCD(Liquid Crystal Display) TV 용 전원 장치는 다중출력 플라이백 컨버터를 사용하여 로직 보드, 영상 보드, LED 백라이트 등의 구동에 필요한 다양한 전원들을 생성, 공급한다. 특히, 기존에는 LED 백라이트의 구동을 위한 출력단에는 부스트 컨버터를 추가하여 LED 전류를 제어하였다. 따라서, 부스트 컨버터에 의한 부피 및 원가가 증가하는 단점이 있었다. 본 논문에서는 부스트 컨버터 없이 보조 스위치 하나만을 사용한 LED 구동회로를 이용하여 LED의 정전류 제어가 가능한 저 가격형 LED 구동회로의 비동기식 제어방법을 제안한다. 최종적으로 제안 회로를 32인치 LCD TV 용 LED 백라이트에 적용하여 그 실험 결과를 바탕으로 제안 회로의 타당성을 검증하였다.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2236-2238
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• 2003

본 논문에서는 항공기 ABS 개발을 위한 시험용 실시간 HILS (Hardware-In-the-Loop-Simulation) 및 제어기 개발을 목적으로 하여, 설계된 ABS 제어 로직에 의해, HILS 구동 제어 결과, 제동 거리, 제동시의 압력인가, 그리고 슬립 마찰 계수와 관련한 시험 결과를 제시하였다.