• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.1028-1033
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• 2002

This paper concerns on a non-rotating axis-active magnetic bearing (AMB) system subject to base motion. In such a system, it is desirable to retain the axis within the predetermined air-gap. Motivated from this, an optimal acceleration feedforward control is proposed to reduce the base motion response without deteriorating other feedback control performances. Experimental results demonstrate that the proposed feedforward control reduces the air-gap deviation to 29% that by feedback control alone.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1404-1407
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• 1996

A quality monitoring system in butt welding process is proposed to estimate weld pool sizes. The geometrical parameters of the weld pool such as the top bead width and the penetration depth plus half back width are utilized to prove the integrity of the weld quality. The monitoring variables used are the surface temperatures measured at three points on the top surface of the weldment. The temperature profile is assumed that it has a gaussian distribution in vertical direction of torch movement and verify this assumption through temperature analysis. A neural network estimator is designed to estimate weld pool size from temperature informations. The experimental results show that the proposed neural network estimator which used gaussian distribution as temperature information can estimate the weld pool sizes accurately than used three point temperatures as temperature information. Considering the change of gap size in butt welding, the experiment were performed on various gap size.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.447-450
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• 2003

This paper concerns on application of active magnetic bearing(AMB) system to levitate the elevation axis of an electro-optical sight mounted on moving vehicles. In such a system. it is desirable to retain the elevation axis within the predetermined air-gap while the vehicle is moving. A disturbance compensation control is proposed to reduce the base motion response. In the consideration of the uncertainty of the system model, a filtered-x least-mean-square(FXLMS) algorithm is used to estimate adaptively the frequency response function of the feedforward control which cancels disturbance responses. The frequency response function is fitted to an optimal feedforward control. Experimental results demonstrate that the proposed control reduces the air-gap deviation to 27.7% that by feedback control alone.

• 소음진동
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• 제8권1호
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• pp.195-203
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• 1998

The magnetic levitation system is utilized in the magnetic bearing of high-speed rotor because of little friction, no lubrication, no noise and so on. The magnetic levitation system need 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 presents the design of robust stabilizing contoller by $H_{\infty}$ control theory using the sensorless method proposed by authors in the magnetic levitation system. And we investigated both the validity of the designed controller and the usefulness of the sensorless magnetic levitation system through results of actual experiment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.40-40
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• 2000

Generally a RF AGC controls the roll gap using the variation of rolling force caused by the roll eccentricity and the entry thickness of material, but these can not be classified. The Feed- forward AGC method, which controls the next stand roll 9ap by estimation the skid mark of the previous stand output thickness is needed to supplement the shortage of RF AGC. In this paper, an improved filtering method of skid mark which take account of the kinds of materials, the final objective thickness and the roll speed is proposed, In addition, an improved estimation method of control point using the speedometer and looper angle is suggested, Via simulation, the performance improvement of the suggested FF AGC method is verified.

• 한국자동차공학회논문집
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• 제12권4호
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• pp.191-197
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• 2004

This paper presents experimental results for human drivers' driving patterns and an Adaptive Cruise Control(ACC) strategy. Analyses have shown that female drivers' driving characteristic values such as time-gap and minimum clearance are larger than those of male drivers'. Human drivers tend to have more clearance margins at high speed than at low speed. At low speed, drivers are much more sensitive to the desired clearance than at high speed. A multi-vehicle detection method is presented to improve ride quality of an ACC. Simulation results have shown that the proposed ACC can provide superior performance compared to the ACC strategy which uses a single-vehicle detection method.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.59-63
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• 2005

Nowadays, various approaches are performed to increase the storage capacity of optical storage device. One of the promising candidates is using the high NA lens. By using high NA lens, the beam spot size can be reduced which will lead to increase the storage density. This paper proposes a double cantilever beam type bimorph PZT actuator for fine motion that can control the gap between the flexible media and optical pickup which uses high NA lens. Mathematical model is derived by using Hamilton's principle and the model is verified by finite element analysis and experiment. Position controller is designed and its performance is evaluated by experiment.

• 유공압시스템학회논문집
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• 제7권4호
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• pp.44-49
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• 2010

This paper represents solenoid design of control valve for incline angle control in variable compressor. Some theoretical and numerical analysis were performed to analyse solenoid and compared with experimental results. Maxwell program was used for numerical analysis. Through redesigns of housing body, plunger, core, and disk in control valve, the needed force was gotten. Reduction of core groove and housing body air-gap had a large influence on magnetic force. But increasing of disk thickness had little effect on magnetic force. Control valve efficiency could be improved through solenoid redesign.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.124-125
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• 2012

본 논문은 변압기나 리액터의 코어에서 국부적 자속포화 현상을 이용하여 코어에 공극(Air Gap)을 추가하는 효과와 동일한 효과를 거두는 것은 물론 자속포화를 일으키는 전류를 제어함으로써 주코일의 자속이 자속 포화 곡선상에서 선형영역과 비선형영역을 모두 포괄하여 제어할 수 있도록 함을 목적으로 한다. 제안하는 기술적 사상의 효과 및 타당성은 간단한 실험을 통해 증명하였다.

• 한국강구조학회 논문집
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• 제28권6호
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• pp.427-438
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• 2016

두본 연구는 실험적인 방법을 통하여 단부판 이음부의 이음면에서 초기 오차로 발생하는 이격이 이음부의 내력 및 거동에 미치는 영향을 평가한 연구이다. 이를 위하여 총 5가지의 단순보형 실험체를 확장형 단부판 이음부를 이용 계획하였고 주요 변수로는 이음면 초기 이격(gap) 여부, 고력볼트 채결 전 끼움판(finger shim plate) 설치 유무, 고력볼트 체결 후 이음면 이격, 고력볼트 채결 후 끼움판 삽입 여부를 적용하였다. 정적가력실험 결과 이음판의 이격은 이음부의 최대휨강도에 미치는 영향은 제한적이나 수직변형과 초기 및 탄성강성에는 영향을 미치는 것으로 나타났으며, 이격을 제어하기 위해 고력볼트 장력을 이용할 경우 고력볼트의 취성파괴 우려도 있는 것으로 나타나서 이들에 대한 충분한 고려가 필요할 것으로 판단된다.