• Journal of Drive and Control
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• v.11 no.2
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• pp.22-29
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• 2014

This paper presents simulation-based analysis of energy flow of a wheel loader. The objective of this study is to analyze the energy flow of a wheel loader during driving and working. Because the wheel loader powertrain consists of a mechanical and hydraulic powertrain, the generated power from the engine is divided into 2 powertrains. Further, a virtual prediction of energy flow in the powertrains is a key factor in terms of optimal design. Accordingly, the simulation model that is able to predict the virtual energy flow is developed and analyzed in this study. The proposed wheel loader simulation model has been constructed in the Matlab/Simulink environment. It is expected that the developed simulation model will analyze the energy flow and efficiency in the design stage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1021-1027
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• 2006

Torque fluctuation of an engine and angular velocity variation of a propeller shaft are the main excitation sources in the vehicle driveline. This paper presents brief mechanism of these excitation sources. Equivalent models of these systems are construced to simulate the excitation source. The computer simulation was carried out by ARLA Simul v 6.7 and ARLA-Simstat v 2.3. Results of the simulations show the characteristics of torsional excitation source of the driveline. Experimental setups for engine system and propeller shaft system are constructed with component of the vehicle. Torque fluctuation of the flywheel and angular velocity of the propeller shaft were measured from this experimental setups. Experimental results are compared with simulation results. The results from experimental analysis agree with those from theoretical results.

• Journal of Power System Engineering
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• v.13 no.6
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• pp.35-42
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• 2009

The piping systems in the steam-driven power engines lie under the cyclic condition of thermal expansion and contraction by superheated steam. These phenomena might cause some severe damages on the pipes and the accessory devices. To avoid these damages, the calculation of the proper strength and the consideration of the reduced resultant forces on the materials are needed. In the present study, numerical investigations on the effects of the thermal deformation of the industrial piping system were performed with comparison of the design data. Commercial software, ABAQUS with the thermal-fluidic loadings based on the design conditions was used for the thermal stress analysis of the piping system. From the analysis of the initially-designed pipe supporters, the rearrangement was suggested to improve the piping design.

• Journal of Power System Engineering
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• v.6 no.2
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• pp.60-67
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• 2002

연삭가공은 나노스케일(Nano-scale)의 미소한 입자 절삭날을 이용한 가공으로, 공작물의 표면을 경면(Mirror surface)으로 가공할 수 있어 제품의 최종 마무리공정으로 사용되어 왔다. 그러나 연삭공정에 있어서는 공구(연삭숫돌)의 수명이 다하거나 가공계(Machining system)가 불안정해지면 채터진동과 연삭버닝 등의 현상이 발생하여 가공물의 표면품위를 저하시키는 요인으로 작용하고 있다. 따라서 본 연구는 원통플른지 연삭공정을 대상으로 공작물에서 발생하는 음향방출 신호와 연삭기 주축 모터의 동력 신호를 연삭가공 중에 검출하고, 이를 신경회로망에 적용하여 연삭가공 상태를 진단하는 시스템을 구축하고, 그 성능을 평가하였다.

• Journal of Power System Engineering
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• v.3 no.4
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• pp.79-85
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• 1999

The magnetic levitation system is utilized in the magnetic bearing of high-speed rotor system because of little friction, no lubrication, no noise and so on. The magnetic levitation system needs the feedback controller for the stabilization of system, and gap sensors are generally used to measure the gap. The use of sensor easily goes into troublesome caused by sensor failure discord between the measurement point and the control point etc. This paper gives a controller design method of magnetic levitation system which satisfies the given $H_{\infty}$ control performance and the robust stability of the presence of physical parameter perturbations. To the end, we investigated the validity of the designed controller through results of simulation.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.910-911
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• 2011

미래사회의 기술적 혁신을 이끌 것으로 생각되는 로봇산업에 대한 관심이 증대되고 있으며, 최근에 많은 기술 개발과 개선이 이루어지고 있다. 이러한 경향은 점차 확대될 것으로 예상되며 전기자동차와 유사한 신성장 동력으로 성장할 것이다. 그러나, 로봇의 핵심 부품인 모터와 같은 구동계는 타분야에 비하여 기술적 혁신 및 관심을 끌지 못하고 있다. 앞으로 로봇산업이 확대 성장하여 산업용 로봇에서 가정용 로봇으로 진화하고, 로봇의 기능적인 측면이 보행, 러닝, 점프 등의 고성능을 구현하기 위해서는 각종 관절을 구동하는 역할을 담당하는 모터 및 동력전달 알고리즘의 연구 개발이 더욱 활발히 이루어져야 할 것이다. 특히, 인간과 유사한 로봇을 구현하기 우하여 보다 Flat하고 가볍고 출력밀도가 높은 새로운 구동장치의 필요성이 증대될 것이다. 본 논문에서는 산업노동지원을 위한 착용식 근력증강 로봇에 적용하는 모터 개발을 목적으로 적합한 구동계 타입을 선정하고, 요구 성능을 만족하는 전동기를 전자계 해석을 통하여 설계하고, 시작품 제작 및 평가를 통하여 해석결과를 검증하였다.

• Journal of Power System Engineering
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• v.10 no.2
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• pp.99-103
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• 2006

The laser interferometer has been used for measurement of the micro displacement error. Although the laser interferometer is widely accepted as a tool for measurement of motion accuracy, the set-up procedure is time-consuming because of the strict requirement on alignment between a laser head and optic units. This paper addresses the development of a laser interferometer to measure the micro displacement for a micro machine. The portable laser interferometer which integrates a laser probe and optics, is developed for the convenient measurement. For the experiment, moving mirror set up on the micro stage. The velocity decoding board is also added to calculate doppler shift frequency directly. The output signal is obtained and analyzed by LabView. Finally experiments are found out the relation between micro displacement and output signal.

• Journal of Power System Engineering
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• v.4 no.4
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• pp.84-91
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• 2000

This paper describes a state feedback controller design method of the integral type magnetic levitation servo system which satisfies the design objectives. The design objective is a $H_{\infty}$ performance, asymptotic disturbance rejection and a robust pole assignment in linear matrix inequality(LMI) region. To the end, we investigated the validity of the designed controller which considering a robust pole assignment region, through results of simulation.

• JOURNAL OF ELECTRICAL WORLD
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• s.445
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• pp.34-39
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• 2014

다사다난했던 2013년. 2013 대구 세계에너지 총회, 세계 최대 요르단민자디젤발전소 착공, ESS 종합추진계획(안) 등 우리 전기계가 미래 성장동력의 지표로 삼아 온 비즈니스모델 성과 창출이 있었습니다. 하지만 원전 납품비리, 여름철 전력수요 위기감 고조 등 안정적인 전력공급을 자부해 오던 전력산업계에 대한 대국민 신뢰가 곤두박질하는 위기상황을 맞기도 했습니다. 이에, 전기협회는 다사다난했던 계사년(癸巳年) 전기계를 뜨겁게 달구었던 이슈와 뉴스를 선정, 게재함으로써 우리 전기계가 가야할 지평(地平)으로 삼고자 합니다.

• Journal of the KSME
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• v.42 no.9
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• pp.36-40
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• 2002