• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7934-7940
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• 2015

The raise of the acceleration can be one of possible methods to increase the scheduled speed of the metropolitan railway system. It is possible to raise the acceleration to the some point by increasing the traction power of the motor. However, there is a limit of the acceleration because the traction power over some level related to the adhesion causes a slip, which prevents from accomplishing the target acceleration. The running resistance is also an important factor to consider. Both the adhesion and the running resistance as well as the traction power vary according to the velocity. Therefore, the standardization of the acceleration needs the analysis of these factors as a function of velocity. In this study, we focus on the advanced urban transit unit(AUTS) for the standardization. We derive a novel equation of the adhesion suitable for the AUTS by investigation of the traction and adhesion equation as well as the experiment data. And finally we propose the standard of the acceleration based on this analysis.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.110.1-110.1
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• 2016

국내외 최첨단 반도체 및 평판 디스플레이 공정에서 필요한 개별 건식 진공펌프들의 자기진단을 통한 예지보수의 실시간 구현 장치 개발과제의 2차년 전반기 수행된 연구결과의 일부를 본 논문에서 소개한다. 본 연구에서 최종 목표로 설정하고 있는 "smart" 진공펌프란 운전상태에 관련된 변수들의 측정치를 기반으로 한 자기진단 (self-diagnostics) 기능을 내장한 차세대 공정용 진공펌프를 의미한다. 1차년에 선정된 상태진단용 진공펌프의 상태변수(state variable)들의 효과적인 수집을 구현하기 위한 연구가 진행되었다. 기존의 반도체 공정용 진공펌프들에서 측정하고 있는 상태변수로는 온도, 유량, 배기관 압력, 모터 소비전류 등과 같은 정적인 변수들뿐 아니라, 회전기계류의 상태진단에 필수적인 진동신호를 추가한 상태 변수 수집 장치를 개발하였다. 본 연구팀은 진공펌프의 회전진동을 유발하는 대표적인 부품은 회전체, 베어링, 그리고 치차로 이들 3 종의 회전진동성분들을 효과적으로 측정할 수 있는 신호처리 기법을 개발하였다. 금번 연구에서 채택한 진동신호 처리기법은 초고속 FFT 변환 기반의 주파수 대역 별 진동 레벨 환산과 더불어 다단계로 구성된 디지털 필터 (multi-staged decimation filter) 기법을 개발 적용하였다. 이러한 신호처리 기법을 통하여 측정된 진동 신호로부터 회전체, 베어링, 그리고 치차의 회전 진동성분을 효과적으로 측정하는 방법을 금번 학술대회에서 소개한다. 그리고, 진공펌프 상태진단에 필요한 상태변수의 실시간 backup 방법, 그리고 공정관리 server와 통신기능, 그리고 펌프 현장 관리자용 PC와 통신 기법 등 상태변수 측정 모듈의 확장성에 대한 기술적 내용을 소개한다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.55-55
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• 2017

본 연구는 파프리카를 자동 수확하기 위한 시스템 개발의 일환으로 수확작업기의 절단장치를 설계하고자 파프리카 과병의 절단특성을 분석하고자 하였다. 파프리카 과병의 절단특성을 분석하기 위하여 사용한 파프리카는 경기도 평택시에서 재배된 파프리카를 사용하였다. 적색 품종인 Nagano RZ와 황색 품종인 Helsinki, 주황색 품종인 Boogie를 사용하였다. 파프리카 과병의 절단 특성을 분석하기 위하여 상기 세 가지 품종의 파프리카 30개씩 총 90개의 파프리카를 사용하여 과병의 중앙 지점을 절단하였다. 절단 특성을 측정하기 위하여 push-pull gauge인 digitect dtg-20을 사용하였으며, 파프리카의 과병의 절단 특성을 측정하기 위하여 일반 농가에서 사용하는 접도 OLFA CK2의 접도의 칼날을 digitect dtg-20에 장착하여 측정하였다. 파프리카 과병의 절단 특성의 시험 항목은 절단강도를 측정하였다. 파프리카의 과병의 절단 특성 측정은 수확작업기의 파프리카 과병의 절단을 위한 절단장치의 설계를 위하여 진행하였다. 파프리카 과병의 절단 특성은 파프리카의 훼손을 최소화한 수확작업을 위한 중요한 요소이다. 파프리카의 과병의 중앙을 절단하여 절단강도와 절단력을 측정하였다. 그 결과 파프리카 과병의 절단강도는 $4.18{\pm}1.18kgf$로 나타났으며, 최대값은 6.91kgf, 최소값은 2.26kgf로 나타났다. 파프리카 과병은 측정된 절단강도의 최대값인 6.91kgf보다 큰 힘을 이용하여 절단하여야 하므로 그에 맞게 수확작업기의 절단장치의 모터를 선정하고 설계가 이루어져야 한다고 판단한다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.5
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• pp.309-317
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• 2004

This paper suggested the vibration characteristic improvement by variation mode of ring type ultrasonic motor. Design for the piezoelectric ceramic and elastic body of stator were calculated by the finite element method(FEM) that consider the resonance frequency, vibration mode and coupling efficiency etc. Through the result of vibration analysis from 6 order mode to 8 mode, the 7 order mode was gained very an excellent results that it was the coupling efficient, minimum power loss and bending vibration value. Here over 7 order mode, this paper was acquired that an output current for input voltage was very a large increased results. The result of vibration calculation, from thickness 0.5[mm] to 2[mm], knew the fact that the vibration displacement at 0.5[mm] is an high value too. From such result, this paper was manufactured the ultrasonic motor of outer diameter 5O[mm] , inter 22[mm] having the about 43.86[KHz] resonance frequency. We have gated that a simulation result is 42.2[KHz] and an experiment result is 43.86[KHzl The propriety of this paper was established though comparison. investigation of simulation and experiment result.

• Journal of Aerospace System Engineering
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• v.14 no.1
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• pp.1-7
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• 2020

This paper discusses a series of procedures and results for designing the gear part of a fuel transfer pump for an aircraft, developed as an independent technology for the first time in Korea. A gear pump type is selected because the design requirements of the fuel transfer pump are met by a gear pump with a characteristics of less leakage inside than a vane pump with superior overall performance. The gear housing is designed with suitable clearance, considering the outer diameter of the gear, which is the main factor on which the flow can be determined. Additionally, the calculation of the required hydraulic and axial force for the motor to drive the fuel transfer pump was performed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.1038-1046
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• 2004

In order to acquire high-speed and high-precision performances in servomechanisms, an integrated design method have been proposed. Based on strict mathematical modeling and analysis of system performance according to design and operating parameters, a nonlinear constrained optimization problem including the relevant subsystem parameters of the servomechanism is formulated. Optimum design results of mechanical and electrical parameters are obtained according to the design parameters specified by designers through the integrated design processes. Motors are optimally selected from the servo motor database. Both the geometric errors referring to Abbe offset and the contour errors are minimized while required constraints such as stability conditions and saturated conditions are satisfied. This design methodology both offers the improved possibility to evaluate and optimize the dynamic motion performance of the servomechanism and improves the quality of the design process to achieve the required performance for high-speed/precision servomechanisms.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.2
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• pp.149-154
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• 2013

This study was performed to develop a high efficiency submersible axial pump for concentration wastewater treatment. To do this, we simulated the effect of some parameters such as the axial twist angle of a blade(${\beta}$), the radial twist angle of a blade(${\alpha}$) and the length of a blade (l) on pump efficiency using commercial code, ANSYS CFX and BladeGen. The results showed that the axial twist angle of a blade(${\beta}$) was the most sensible parameter on the pump efficiency. And the pump efficiency had a maximum at ${\beta}=20^{\circ}$, ${\alpha}=110^{\circ}$ and l=240 mm.

• Composites Research
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• v.16 no.2
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• pp.1-8
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• 2003

Thus paper summarizes the procedures to develop the downscaled payload kick motor for KSR-III by KARI. Filament winding-a well-known method of manufacturing composite motor case - is adopted to reduce structural weight. Netting and lamination theories are used to determine adequate winding thickness under required internal pressure. Dome shapes are designed considering feasible winding patterns and easiness of mandrel manufacturing. T-800 carbon fiber and Novolac type resin are selected for weight-reduction. The separate mandrels are disassembled and removed after filament winding. The manufacturing process of real payload kick motor is developed from the design experience of downscaled ones.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.676-683
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• 2005

In this paper, we proposed a method that optimal values of fuzzy control rule base and quantization of membership function are searched by genetic algorithm. Proposed method searched the optimal values of membership function and control rules using genetic algorithm by off-line. Then fuzzy controller operates using these values by on-line. Proposed fuzzy control system is optimized the control rule base and membership function by genetic algorithm without expert's knowledge. We investigated proposed method through simulation and experiment using DC motor and one link manipulator, and confirmed the following usefulness.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.6
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• pp.113-118
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• 2011

Fuel Cell Hybrid Vehicle (FCHV) is one of the most promising candidates for the next generation of transportation. It has many outstanding advantages such as higher energy efficiency and much lower emissions than internal combustion engine vehicles. It also has the ability of recovering braking energy. In order to design an FCHV drive train, we need to determine the size of the electric motor, the Fuel Cell System (FCS), and the battery. In this paper, the methodology for the sizing of these components is introduced based on the driveability constraints of the FCHV. A power management strategy is also presented because the battery energy capacity depends on it. The warm-up time of the FCS is also considered in the power management strategy and the simulation result is compared to that without considering the warm-up time.