• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.123-124
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.125-126
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• 2010

• The Optical Journal
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• s.100
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• pp.65-73
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• 2005

고정 지립, 즉 지석으로 경면 가공한 새로운 연삭 가공법이 확립되면서 또한 초정밀한 운동 정밀도를 가진 기계 요소와의 결합에 따라 광학 부품이 나 전자 부품에 이용되는 기능성 재료를 고품위·고능률로 경면 가공하는 초정밀 연삭 기술로 계속 발전하고 있다. 유리 지립을 이용하는 연마 가공이 고정 지립화의 필요성이 요구되는 현실을 받아들이고, 새로운 연삭 기술은 가공 품위, 형상, 거칠기, 정밀도, 능률 등의 성능을 종합적으로 최적화하는 초정밀 연삭 기술로서 그 위치를 다지기 시작한 것으로 인식되고 있다. 이러한 기술의 하나로[ELID 연삭법]이 있는데, 본 기술은 최근 다양한 공업 생산에 실용화되기 시작하면서 많은 연구 개발 분야에서도 확립되기 시작했다. 본 고에서는 ELID 연삭법의 원리, 효과, 적용 그리고 장치와 응용에 대해 설명한다.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.2
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• pp.229-238
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• 2012

This study is to compare muscle strength between isotonic exercise and isotonic & isokinetic exercise. Participants are 12-man and 10-woman whom they are healthy without medical history in shoulder, elbow and lumbar joint. We performed experiment total 4-weeks that exercise 3-days a week each exercise pattern. We measured shoulder, elbow and lumbar joint torque with BIODEX and circumference of muscle in upper arms once a week. The result showed that isotonic & isokinetic exercise pattern significantly more improved joint torque in shoulder, elbow, lumbar than isotonic exercise pattern. Because that isotonic & isokinetic exercise pattern supplied muscle strengthen and caused muscle contraction. This exercise pattern can be used new exercise training method for major athlete and normal people. Also this pattern can be used rehabilitation treatment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.213-220
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• 2016

This research aims to develop core technologies for passive carrier (no power in carrier itself) transfer system. The technologies are passive levitation, propulsion, and guidance, which can be great benefits for semiconductor and display manufacturing industries. Passive maglev carrier is necessary to precise position control for quiet and stable transfer operation. However, the structural characteristics of carrier and the installation errors of gap sensors cause the pitch motion. Hence, the controller design in consideration of pitch motion is required. This study deals with the reduction control of carrier pitch motion. PDA controller and PDA controller with pitch control are proposed to compare the pitch angle analysis. The pitch angle and the levitation precision are measured by experiment. Finally, the optimized design of pitch controller is presented and the effects are discussed.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.126-137
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• 1993

This paper presents an efficient method for the identification of motion error sources in NC machine tools by making use of the circular interpolation test, which is often used in estimating the motion accuracy of NC machine tools. Mathematical formulae are described for motion errors due to various kinds of error sources. Two identification formulae are proposed: one is based on the frequency analysis and the other is formulated with the weithted residual method. Motion error signal is classified into two patterns, mean errors(mean of CW and CCW test signals from mean errors). The sources of the mean errors are identified by using the frequency analysis technique and the sources of the deviation errors by the weighted residual formulaltion. A menu driven, user oriented, computer program is written to realize the full steps of the proposed identificationprocedure. Then, the identification method is applied to two NC machine tools.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.719-722
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• 2002

Cylindrical cam mechanisms are used commonly in many automatic machinery. But the cylindrical cam is very difficult to design and manufacture the shape. The motion analysis of the cylindrical cam can check the accuracy between designed data and manufactured data of the cam shape and can reproduce without the cam design data. The motion analysis of the cylindrical cam consists of displacement analysis, velocity analysis and acceleration analysis. This paper performs the motion analysis of a cylindrical cam with translating follower by using a relative velocity method and a central difference method. The displacement is calculated by using the central difference method and the velocity is calculated by the relative velocity method. The relative velocity method is defined by the relative motion between follower and cam at a center of a follower roller. The central difference method is derived in the 3 dimensional space.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.704-708
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• 2004

The RMD(Rehabilitation Medicine Device) with CJM(Compound Joint Motion) is the lower limb unit muscular strengthening promotion rehabilitation medicine device for patients of joint orthopedic operation or the deficient elder of ability to walk, the handicapped. Since the products for the rehabilitation medicine device have limited to the simplicity linear motion, those do not give efficient the lower unit muscular strengthening effects. This device which was under the development gives to exercise of hip joint and knee joint with user's selection at once, get out of the simplicity linear motion. Also it will be contributed to a field of rehabilitation medicine and a mobility aid technology of the deficient elders of ability to walk, the handicapped.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.546-549
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• 1995

This paper presents a control of washing machine using ER clutch and brake actuators. After analyzing field- dependent torque of the actuators on the basis of Bingham model of the ER fluid, two sets of cylindrical ER clutch and brake are manufactured. The governing equation of motion for washing and dehydrating are derived by considering actuators' dynamics. Subsequently, PID controllers are designed to achieve desired rotational motions and tracking control results are provided to demonstrate the effectiveness of the proposed method.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.95-103
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• 1999

수중운동체가 수중에서 진행할 때 외부 파도에 의한 불확실한 부하 저항을 받으므로 이에 대응하는 핀(조타) 구동부의 제어 문제를 고려한다. 본 논문에서 제시하는 제어기는 본체로부터의 지정 각도를 부여 받으면 이에 부응하여 핀의 각도와 각속도를 이용하여 제어기의 알고리즘을 구축하여 지정된 경로를 추적하게 한다. 또한 핀의 각속도 정보의 이용이 부득이 어려운 상황에 대처하기 위하여 핀의 각도만을 이용한 출력제어기나 추정기를 설계하여 주위 환경의 불확실성을 극복할 수 있는 제어기를 제안한다. DC서보 모터로 구성괸 핀 구동부에 대해 실제 데이터를 사용하여 제안된 제어기의 성능을 시뮬레이션을 통하여 검증한다.