• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.499-502
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• 1989

This paper is concerned with the stability analysis and the design of an auto pilot using direct model reference adaptive control for BTT missile with unknown dynamics when subjected to the longitudinal and lateral gusts. A motion of BTT missile can be separated into the longtudinal and lateral motione. The proposed algorithm is introduced different leakage terms about each motion into adaptation so as to prevent drift of the adaptive gain and alleviate gust effects and cross-coupling. The algorithm is applied to the 6DOF motion of an EMRAAT missile.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2000년도 추계종합학술대회논문집
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• pp.201-204
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• 2000

This paper describes a study on the time-varying control of parameters in learning of the neural network. Elman recurrent neural network (RNN) is used to implement the control of parameters. The parameters of learning and momentum rates In the error backpropagation algorithm ate updated at every iteration using fuzzy rules based on performance index. In addition, the gain and slope of the neuron's activation function are also considered time-varying parameters. These function parameters are updated using the gradient descent algorithm. Simulation results show that the auto-tuned learning algorithm results in faster convergence and lower system error than regular backpropagation in the system identification.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.165-167
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• 2001

This paper presents a study on successive approximation measurement of mechanical parameters for motor control system. At the first step of servo system installation, control system gain tuning is troublesome work. Recently, auto-tuning method of motion controller for motor drive system is based on parameter measurement and identification. On the case of first order mechanical system (mechanical parameters are modified by simple inertia and friction), it is necessary for good response to get the accurate measurement or identification of the mechanical parameters. In this paper, novel method applies the binary successive approximation measurement to the inertia and friction coefficient. Computer simulation and experiment for the proposed method will show verification of accuracy and usefulness.

• 대한전자공학회논문지SP
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• 제47권4호
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• pp.56-62
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• 2010

자동노출제어는 카메라에서 연속적을 입력되는 영상의 밝기를 유지하기 위하여 적절한 센서이득 혹은 노출 결정하는 것을 이야기 한다. 최근 노출제어는 영상의 정보 보다는 하드웨어적 장치를 적용하나, 모바일 폰 카메라에서 영상의 평균 밝기와 센서이득 혹은 노출 만을 이용한다. 또한 모바일 장치의 하드웨적 성능고려하여야 하며, 부적절한 제어로 발생하는 flicker 현상을 제거하여야 한다. 따라서 제안된 자동노출제어는 flicker 현상의 제거 및 실시간 수행을 위하여 입 출력 특성곡선에 기초한 Look Up Table(LUT)을 사용한다. 제안된 방법에서는 선행 작업으로 카메라의 센서이득에 따른 입력과 출력 특성을 LUT로 만들어 저장한다. 노출제어에 있어서 먼저 저장된 LUT의 정보와 현재의 센서이득을 통하여 현재 입력 영상에 상응하는 패치를 추정한다. 그리고 추정된 패치와 LUT의 정보를 또다시 이용하여 추정된 패치가 목표 밝기를 가질 수 있도록 하는 최종적인 센서이득을 추정할 수 있게 된다. 제안된 방법은 LUT를 사용함으로써 다음 프레임의 센서이득을 실시간으로 추정 할 수 있고, 또한 반복적 수행 없이 정확한 센서이득을 추정함으로써 flicker를 제거 할 수 있다. 실험 결과영상에서 제안된 방법이 실시간으로 자동노출제어를 할 수 있음을 확인하였다.

• 대한전기학회논문지
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• 제38권7호
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• pp.557-568
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• 1989

Using Power Spectrum Analysis, conditions of parameter convergence for a Model Reference Adaptive Control (MRAC) system are described. The general Persistent Excitation (PE) condition given in time domain can be transformed to the positiveness of auto-correlation matrix which is represented in frequency domain by the spectra of reference input signal. For an MRAC system designed with relative degree one, the existence and the uniqueness of parameter nominal values due to the variation of input spectra can be analyzed by the PE condition in frequency domain. If the input signal has 2n spectra or more, it can be shown that the nominal values exist independent of adaptive gain, input amplitudes, and magnitudes or numbers of their spectra.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1508-1510
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• 2003

비접촉 방식인 광 삼각측량법(optic triangulation method)에 의한 고정도 변위센서를 반도체 레이저 다이오드와 리니어 CCD를 이용하여 구현하였다. 개발한 고유의 알고리듬을 채용하여 측정 분해능 보다 적은 CCD pixel(256 pixel)로 고분해능(2,560분해능, $4{\mu}m$)을 실현함으로써, 결과적으로 저가이며 소형의 고정도 변위센서를 개발하였다. 또 검출물체의 색상이나 재질에 따른 검출특성의 현저한 차이를 보상하기 위하여 LFTC(laser flash time control)과 AGC(auto gain control)을 적용하여 안정된 검출결과를 얻을 수 있었다. 개발된 변위센서의 특성은 다음과 같다. 측정 거리:30mm, 유효측정 범위: -5.09${\sim}$5.10mm, 분해능:4um, 직선성:${\pm}1%$.

• Journal of Power Electronics
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• 제12권4호
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• pp.519-527
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• 2012

A high step-down multiple-output LED driver is proposed in this paper. Firstly, the derivation of the driver with dual-output is presented and its operation principle and steady state performance are analyzed in detail. Secondly, a high step-down N-channel LED driver is proposed and its current auto-balance characteristic and step-down ratio are analyzed. Finally, an experimental prototype is built and the experimental results are given. The theoretical analysis and experimental results show that the proposed driver has the following virtues: First, if load balancing is achieved, the voltage gain is 1/N that of a Buck driver, where N is the number of channels. Second, each output automatically has an equal output current, without requiring more current close-loop control circuits than a Buck driver. Last, the voltage stresses of the switches and diodes are lower than those of a Buck driver, meaning that lower voltage switches and diodes can be used, and a higher efficiency can be expected.

• 한국산학기술학회논문지
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• 제10권7호
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• pp.1497-1502
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• 2009

자동노출은 피사체나 광원의 밝기 변화에 대응하여 카메라로부터 취득된 영상의 노출치를 일정하게 유지시켜주는 기능을 나타내며, CIS 기반 모바일 카메라의 핵심 구성 요소 중의 하나이다. 일반적으로 자동노출 알고리즘은 소프트웨어로 구현되어 CPU와 소프트웨어를 저장하기 위한 ROM을 내장하는 구조를 가지는데, 이는 유연성을 확보하는 대신 CPU와 메모리라는 비용증가로 이어지게 된다. 본 논문에서는 CIS 기반 모바일 카메라를 위하여 임의의 프레임율 가변기능과 아날로그 게인 조정이 가능한 자동 노출 알고리즘을 제안하고, FSM 기반으로 구성된 하드웨어 구조를 제안한다.

• 자동차안전학회지
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• 제11권2호
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• pp.23-28
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• 2019

This paper presents an optimal performance of rear wheel steering vehicle for maneuverability. The maneuverability of vehicle is evaluated in terms of yaw rate, body slip angle and driver input. The maneuverability of vehicle can be improved by rear wheel steering system. To obtain optimal performance of rear wheel steering vehicle, the optimal control history is designed. The high dimensional trajectory optimization problem is solved by formulating a quadratic program considering rear wheel steer input. To evaluate handling performance 7 degree-of-freedom vehicle model with actuation sub-models is designed. A step steer test is conducted to evaluate rear wheel steering vehicle. A response time, a TB factor, overshoot, and yaw rate gain are investigated through objective criteria, assessment webs. The handling performance of vehicle is evaluated via computer simulations. It has been shown from simulation studies that optimal controlled rear wheel steering vehicle provides improved performance compared to others.

• Journal of Advanced Marine Engineering and Technology
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• 제39권5호
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• pp.577-585
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• 2015

This paper deals with development of an autopilot system for leisure yacht based on NMEA 2000 network and android platform. The developed system can operate both for manual steering and automatic navigation mode. In automatic steering mode, after manipulation of commands which are NMEA 0183 sentences by android platform, the developed system translates and sends the packets through NMEA 2000 network. Then the controller which is connected to NMEA 2000 network receives the commands and controls the boat's rudder system automatically. The automatic steering mode is achieved by cooperation of two controllers; one for controlling the rudder system, and the other for controlling the vessel's heading. To control the vessel's rudder and heading angle two PID controllers are developed with an adjustable dead-band gain. Also, in order to eliminate the steady-state error occurred by applying dead-band, an integral controller which specifically supervises the system's behavior inside the dead-band area is developed. In this paper, at the first stage, simulations are accomplished using computer in order to examine the feasibility of the proposed based on simulation results. In the next step, the system on a real hydraulic steering model is implemented and at the end the performance examination by implementing it on a real boat and doing test navigation is executed.