• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.341-344
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• 1991

Current controlled pulse width modulation(PWM) for voltage source inverter(VSI) is one of the control method which controls the current directly so that we can perform vector control because it reduces the orders of differential equations of the induction machine. This paper propose a Fuzzy current controlled PWM which properly minimize a current ripple using Fuzzy theory in a constant switching frequency. This technique is applied to an electrical drive system with an induction machine(IM) by simulation. By comparison with the known classical method such as ramp comparison, hysteresis band method, our contribution shows the better performances.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1196-1198
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• 1992

In field oriented control of Induction motors, speed sensor is required, which reduces the sturdiness of drive system and together with the expenditure of hardware for faultless transmission and processing of sensor signals it causes considerable expenses. These expensive sensors can be replaced by speed sensorless concept. And for good control, the knowledge of the rotor flux component of the rotor resistance are needs. Thus, this paper is based on a Extended Kalman Filter( EKF ) that estimates the state variables that are required for the control by only measuring the line voltages and currents of the machine. The rotor time constant and speed estimated by the EKF shows satisfactory agreement with the real values, with the simulation approaches.

• 대한의용생체공학회:의공학회지
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• 제31권1호
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• pp.1-13
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• 2010

There are a great numbers of disabled individuals who cannot freely move or control specific parts of their body because of serious neurological diseases such as spinal cord injury, amyotrophic lateral sclerosis, brainstem stroke, and so on. Brain-computer interfaces (BCIs) can help them to drive and control external devices using only their brain activity, without the need for physical body movements. Over the past 30 years, several Bel research programs have arisen and tried to develop new communication and control technology for those who are completely paralyzed. Thanks to the rapid development of computer science and neuroimaging technology, new understandings of brain functions, and most importantly many researchers' efforts, Bel is now becoming 'practical' to some extent. The present review article summarizes the current state of electroencephalogram (EEG)-based Bel, which have been being studied most widely, with specific emphasis on its basic concepts, system developments, and prospects for the future.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2169-2171
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• 1998

In order to improved the three phase GTO CSI of high efficiency IM drive with low loss commutation and snubber energy, we studied the energy recovery circuit to recover stored energy in clamping capacitor, dc link inductor and snubber capacitor, used an induction motor as the load of inverter. Specially, we investigated how dc input power is increased or decreased according to size of dc link inductor. The validity of this system is proved through experiment.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.299-304
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• 2005

A Vigilance control is a device fitted in the driving cab of a railway train to ensure that the driver is alert on the job. A simple vigilance control requires that the driver press a button at intervals not less than a certain amount and not more than another amount of time. If the driver fails to operate the vigilance control within those limits, a hooter sounds, and should the driver still doesn't operate the vigilance control then the brakes are applied. If the driver falls asleep or takes ill, then clearly such a vigilance control will sooner or later apply the brakes. The this vigilance control system which is applied to reduce the drive load at Syria diesel multiple unit train is proposed.

• 드라이브 ㆍ 컨트롤
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• 제16권4호
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• pp.38-47
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• 2019

In this paper, a real-time simulation model of an excavator using Amesim was proposed, considered the operation of functional valves with the main control valve (MCV). The hydraulic system models including the pump and MCV have been developed. The kinematic and dynamic models of the manipulator have also been developed, to confirm the behavior of the excavator. The MCV model includes various functional valves such as the regenerative valves, holding valves, swing and boom priority valves, and regen-cut valves so that simulations similar to real excavators can be performed. Additionally, to obtain the real-time calculation performance, the parts with no major influence on the dynamic behavior were simplified, high frequency factors were removed, and parameters were optimized. The models were compared with each other through the numerical analysis with variable time-step and fixed time-step, and the results were verified by comparison with the results of the actual vehicle tests.

• 대한원격탐사학회지
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• 제26권6호
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• pp.629-644
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• 2010

A real-time image georeferencing system requires all inputs to be determined in real-time. The intrinsic camera parameters can be identified in advance from a camera calibration process while other control information can be derived instantaneously from real-time GPS/INS data. The bottleneck process is tie point acquisition since manual operations will be definitely obstacles for real-time system while the existing extraction methods are not fast enough. In this paper, we present a fast-and-automated image matching technique based on the KLT tracker to obtain a set of tie-points in real-time. The proposed work accelerates the KLT tracker by supplying the initial guessed tie-points computed using the GPS/INS data. Originally, the KLT only works effectively when the displacement between tie-points is small. To drive an automated solution, this paper suggests an appropriate number of depth levels for multi-resolution tracking under large displacement using the knowledge of uncertainties the GPS/INS data measurements. The experimental results show that our suggested depth levels is promising and the proposed work can obtain tie-points faster than the ordinary KLT by 13% with no less accuracy. This promising result suggests that our proposed algorithm can be effectively integrated into the real-time image georeferencing for further developing a real-time surveillance application.

• 한국항행학회논문지
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• 제19권4호
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• pp.311-317
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• 2015

본 논문에서는 서비스 로봇 제어 시스템의 복잡한 소프트웨어 개발을 손쉽게 하기 위한 서비스 로봇 콘텐츠 개발 방법에 관한 연구이다. 본 연구에서 개발된 User created contents 기반 로봇 제어 시스템은 로봇 구동 제어회로, 센서 데이터 처리, 상태 표시, 모니터링 시스템 등을 모듈화 하여 사용자 입장에서 서비스 로봇 운용 화면을 구성하고 서비스 로봇을 운용 제어할 수 있는 시스템으로써 텍스트 기반에서 서비스 로봇 제어 콘텐츠를 자유롭게 운용할 수 있는 특징을 가진다. 또한, 사용자는 개발된 User created contents 를 이용하여 위치 변경뿐만 아니라 사용자가 원하는 로봇 운영 제어 GUI (graphic user interface) 도 변경이 가능하다는 장점을 가지고 있다. 결과적으로, 서비스 로봇 운용자가 사용자 입장에서 편리하게 서비스 로봇 콘텐츠를 만들 수 있는 방법을 제안하여 서비스 로봇의 개발을 활성화하는 방법을 제시하였다.

• Spatial Information Research
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• 제21권6호
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• pp.57-67
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• 2013

GPS 기반 차량 내비게이션은 신호 수신이 어려운 터널과 빌딩 숲 같은 곳에서 위치 정확도가 현저히 떨어진다. 이에 본 연구는 GPS 없이 차량의 내부 센서 데이터만을 이용하여 위치 자세를 결정하는 방법을 제안한다. 제안한 방법의 실현 가능성 확인하기 위하여 내부 센서 데이터와 기준 데이터를 동시에 취득할 수 있는 시스템을 구축하였다. 취득된 데이터와 이를 이용하여 제안된 방법으로 추정한 경로에 대한 정확도 평가를 수행하였다. 내부센서로 측정된 속력과 각속도는 각각 1.1 km/h와 0.8 deg/s정도의 RMS 오차를 보였고, 이를 이용하여 추정한 경로는 약 15분 정도 주행했을 때 20.8 m의 RMS 오차를 보였다. 향후 카메라와 GPS 등의 추가센서와 융합하면, 고가의 고정밀 외부 IMU가 없어도 높은 정확도의 저가 내비게이션으로 활용될 수 있을 것으로 판단된다.

• 한국기계가공학회지
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• 제20권11호
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• pp.74-79
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• 2021

Generally, multi-legged walking robots have excellent mobility in rough and uneven terrain, and they are deployed for the safety of rescuers in various disaster environments. However, as each leg is driven by a number of actuators, it leads to a complicated structure and high power consumption; therefore, it is difficult to put them into practical use. In this article, a new concept is proposed of a walking robot whose legs are driven by a complex linkage structure to overcome the deficiencies of conventional multi-legged walking robots. A double crank-rocker mechanism is proposed, making it possible for one DC motor to actuate the left and right movements of two neighboring thighs of the multi-legged walking robot. Each leg can also move up and down through an improved cam structure. Finally, each mechanism is connected by spur and bevel gears, so that only two DC motors can drive all legs of the walking robot. The feasibility of the designed complex linkage mechanism was verified using the UG NX program. It was confirmed through actual production that the proposed multi-legged walking robot performs the desired motion.