• 전기학회논문지
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• 제61권9호
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• pp.1380-1386
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• 2012

It is important to consider supply voltage stability in case of design and construction of a substation at electric railway because a urban transit is operated by electricity and it is driven simultaneous in the same section. This paper study on variation of the dynamic characteristic of supply voltage according to the track environment and spatial distribution as driving of urban transits. Simulation tool, TOM(Train Operations Model) software is used to ensure stability of feeder system being used around the world. As results of simulation, voltage of the contact wire is in limits on driving operation diagram of urban transits. Also, it has confirmed that there is a correlation the phase current, depending on the speed of urban transit and track environment like vertical gradients and curve radius.

• Journal of Magnetics
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• 제12권1호
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• pp.35-39
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• 2007

A highly sensitive magnetic sensor using the Giant MagnetoImpedance effect has been developed. The sensor performance is studied and estimated. The sensor circuitry consists of a square wave generator (driving source), a sensing element in a form of composite wire of a 25 $\mu$m copper core electrodeposited with a thin layer of soft magnetic material ($Ni_{80}Fe_{20}$), and two amplifier stages for improving the gain, switching mechanism, scaler circuit, an AC power source driving the permeability of the magnetic coating layer of the sensing element into a dynamic state, and a signal pickup LC circuit formed by a pickup coil and an capacitor. Experimental studies on sensor have been carried out to investigate the key parameters in relation to the sensor sensitivity and resolution. The results showed that for high sensitivity and resolution, the frequency and magnitude of the ac driving current through the sensing element each has an optimum value, the resonance frequency of the signal pickup LC circuit should be equal to or twice as the driving frequency on the sensing element, and the anisotropy of the magnetic coating layer of the sensing wire element should be longitudinal.

• 드라이브 ㆍ 컨트롤
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• 제20권4호
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• pp.140-149
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• 2023

Wire harness is a component for efficient control when electronic parts are required such as construction machinery and electric vehicles. With emerging issues such as autonomous driving and automation in construction, a wire harness composed of multiple cables has become an essential part because more electronic parts are required. However, when a wire harness failure occurs, systems can be stopped, accidents can occur, and economic damage can be significant. Therefore, in this paper, we developed a digital fault screening system that could easily and quickly diagnose faults in the wire harness. The principle of the developed system was to sequentially send pulse signals to the wire harness and use returned signals to perform fault detection. As a result of diagnosing faults using the developed failure detection system, a detection accuracy of 99.9 % was confirmed through the experiments.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.423-424
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• 2007

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.351-355
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• 1996

In optical disc system, lens actuator of 4-wire has unwanted moment which occurs tilt. The moment around the axis pallet to the tangential direction of the disk occurs to the moving part. when the moving part is moved in tracking direction and focus driving force is applied. This paper analyzed coupled effect due to the moment based on structural analysis and magnetic field analysis, both using finite element method.

• 전기학회논문지
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• 제66권3호
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• pp.587-592
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• 2017

In the three-phase four-wire low-voltage power distribution equipment, single-phase and three-phase load have been used mainly mixed. Also linear and nonlinear loads have been used together in the same conditions. In a three-phase four-wire distribution line, the current distribution of three-phase linear load is almost constant in each phase during driving or stopping, but the single-phase load is different from each other for each phase in accordance with the operation and stop. So that the voltage unbalance is caused by the current difference of each phase. In the three-phase four-wire distribution system, non-linear load is used with linear load. The presence of single-phase nonlinear loads can produce an increase in harmonic currents in three-phase and neutral line. It can also cause voltage unbalance. In the present study, we analyzed for the voltage unbalance fluctuations by the operation pattern of the single and three-phase linear and non-linear load in three-phase four-wire low voltage distribution system.

• 한국항공우주학회지
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• 제44권3호
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• pp.274-280
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• 2016

2015년 발사예정인 우주기반기술 검증용 큐브위성 STEP Cube Lab.의 주요 탑재체인 열선절단방식 힌지구동형 구속분리장치는 높은 체결력 및 저충격 구현의 장점으로 초소형위성 전개구조물의 구속/분리에 적용이 용이하며, 기존 나일론선 절단방식의 낮은 체결력 및 복수구조물 적용에 따른 시스템 복잡화의 단점을 극복가능하다. 본 논문에서는 인증모델 검증시험이 완료된 구속분리장치의 궤도검증 임무수행을 목적으로 체결력 검증 및 전개 확인 신호 획득이 가능한 비행모델을 설계/제작하였으며, 탑재체 레벨에서의 발사 및 궤도환경 검증시험을 수행하여 설계 유효성을 입증하였다.

• 한국소음진동공학회논문집
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• 제21권1호
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• pp.3-8
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• 2011

This paper introduces a robot eye module, of which two degree-of-freedom motions, i.e. panning and tilting, are driven by a pair of wires. The main feature of the module is that each wire can generate push-pull motion without buckling. It is thanks to a Teflon tube which guides the path of the moving wire. End points of the tube and wire have pivot elements so that a smooth push-pull motion is produced even when the end point of wire is moved by eye rotation. This mechanism helps the eye module to be very compact. In this paper, the structure of the robot eye module is introduced in detail, and the required motor angles for a certain direction of eye line are investigated analytically and experimentally.

• 한국유체기계학회 논문집
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• 제18권3호
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• pp.26-32
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• 2015

The authors are developing a motion of floater body type wave energy converter of the float-counterweight system. This consists of the driving pulley, wire, float and counterweight suspended from idler pulleys and rachet mechanism. Though it has succeeded in solving the major structural strength problem in which the floats would slam against adjacent structure(s) by wave load acting horizontally. In order to overcome this problem. We propose a new system in which the wire transmitting the power is wound around the pulleys and the float receiving the wave power is pulled by the wire from both its upper and lower ends to avoid the occurrence of slackening during the wave cycle. In the paper, we developed the dynamics model for the proposed system. Energy gain has been calculated for realistic wave conditions and compared with the original float-counterweight device. The important differences from the float-counterweight system are that (1) both upward and downward motions of water surface can be utilized without problem. (2) slackening of energy gain and wire tension are effectively suppressed, and (4) for the same time averaged energy gain, the maximum wire tension is fairly lowered.

• 품질경영학회지
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• 제50권3호
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• pp.533-543
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• 2022

Purpose: The purpose of this study is to identify and resolve the causes of defects in the unmanned aerial vehicle launch system(propulsion wire fracture, rear rail deformation) and to prevent recurrence. Methods: The causes of the two defects were derived through fault tree analysis for each of the two defects and fault reproduction tests. In the case of propulsion wire, the installation of a high speed camera to check the behavior of wire was the driving force behind the defect resolution. Results: The results of this study are as follows; It was determined that the thickness of the washer was less than the maximum tolerance of the pulley was the cause of the propulsion wire fracture defect. Failure to comply with the launch procedure and insufficient safety margin were judged as the cause of the rear rail deformation defect. Accordingly, the configuration was changed to remove each defect. Conclusion: The case of this study was conducted to eliminate defects in the launch system for UAV. The causes of defects were estimated through fault tree analysis. After the configuration change, Structural analysis and launch tests were performed to demonstrate the safety and effectiveness of the modified configuration. As a result, the effect of the modified configuration was verified.