• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.70.1-70.1
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• 2005

• 한국재료학회:학술대회논문집
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• 한국재료학회 1997년도 한국재료학회 추계학술발표회
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• pp.13-13
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• 1997

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 하계학술발표대회 논문집
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• pp.116-116
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• 2007

• Journal of Mechanical Science and Technology
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• 제16권6호
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• pp.799-809
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• 2002

In order to utilize a parallel mechanism as a machine tool component, it is important to estimate the errors of its end-effector due to the uncertainties in parts. This study proposes an error analysis for a new parallel device, a cubic parallel mechanism. For the parallel device, we consider two kinds of errors. One is a static error due to link stiffness and the other is a dynamic error due to clearances in the parts. In this study, we propose a stiffness model for the cubic parallel mechanism under the assumption that the link stiffness is a linear function of the link length. Also, from the fact that the errors of u-joints and spherical joints are changed with the direction of force acting on the link, they are regarded as a part of link errors, and then the error model is derived using forward kinematics. Lastly, both the error models are integrated into the total error, which is analyzed with a test example that the platform moves along a circular path. This analysis can be used in predicting the accuracy of other parallel devices.

• Journal of Mechanical Science and Technology
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• 제17권3호
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• pp.380-390
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• 2003

This paper addresses the problem of the modeling and vibration control of tapered rotating blade modeled as thin-walled beams and incorporating damping capabilities. The blade model incorporates non-classical features such as anisotropy, transverse shear, secondary warping and includes the centrifugal and Coriolis force fields. For the rotating blade system, a thorough validation and assessment. of a number of non-classical features including the taper characteristics is accomplished. The damping capabilities are provided by a system of piezoactuators bonded or embedded into the structure and spread over the entire span of the beam. Based on the converse piezoelectric effect, the piezoactuators produce a localized strain field in response to a voltage and consequently, a change of the dynamic response characteristics is induced. A velocity feedback control law relating the piezoelectrically induced transversal bending moment at the beam tip with the appropriately selected kinematical response quantity is used and thebeneficial effects upon the closed-loop dynamic characteristics of the blade are highlighted.

• Journal of Mechanical Science and Technology
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• 제18권4호
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• pp.560-572
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• 2004

Aeroelastic response and control of airfoil-flap system exposed to sonic-boom, blast and gust loads in an incompressible subsonic flowfield are addressed. Analytical analysis and pertinent numerical simulations of the aeroelastic response of 3-DOF airfoil featuring plunging-pitching-flapping coupled motion subjected to gust and explosive pressures in terms of important characteristic parameters specifying configuration envelope are presented. The comparisons of uncontrolled aeroelastic response with controlled one of the wing obtained by feedback control methodology are supplied, which is implemented through the flap torque to suppress the flutter instability and enhance the subcritical aeroelastic response to time-dependent excitations.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 추계학술논문집 2부
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• pp.409-412
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• 2011

본 논문에서는 나노 분해능을 가지면서 수mm의 이송능력을 가지는 AFM용 스캐너의 구현을 위하여 새로운 형태의 더블-벤트 유연 가이드를 연구하였다. Castigliano 이론을 이용하여 유연 가이드의 강성을 구하였으며, 모든 과정은 FEA(Finite Element Analysis)를 통하여 이론의 타당성을 검증하였다. 또한, 더블-벤트 유연 가이드의 성능 검증을 위하여 평면 스캐너의 모델링에 응용하여 보았다. 응용된 평면 스캐너의 구성 요소 성분 변수들은 Double-bent 유연 가이드의 나노 분해능 및 이송 변위의 최대화를 구현함과 동시에 빠른 응답 속도를 보장하기 위해 최적화 설계를 통하여 이루어졌다. 더블-벤트 유연 가이드를 적용한 평면 스캐너 역시 FEA를 통한 검증 단계를 거쳤다.

• Journal of Mechanical Science and Technology
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• 제16권3호
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• pp.310-319
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• 2002

This paper deals with the analytical modeling, and the experimental verification of the strain rate self-sensing method using a hybrid adaptive filter for a cantilevered piezoelectric beam. The piezoelectric beam consists of two laminated lead zirconium titanates (PZT) on a metal shim. A mathematical model of the beam dynamics is derived by Hamilton's principle and the accuracy of the modeling is verified through the comparison with experimental results. For the strain rate estimation of the cantilevered piezoelectric beam, a self-sensing mechanism using a hybrid adaptive filter is considered. The discrete parts of this mechanism are realized by the DS1103 DSP board manufactured by dSPACE$\^$TM/. The efficacy of this method is investigated through the comparison of experimental results with the predictions from the derived analytical model.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1379-1380
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• 2015

본 논문에서는 고도유지 제어기를 포함한 자율이동체의 수직 채널 안정화 루프를 제안한다. 제안된 방법은 일반적으로 널리 사용되고 있는 고전적인 수직채널 댐핑루프와 달리 고도정보와 함께 속도정보를 이용하여 궤적의 고도변화가 큰 이동체에 대하여 빠른 응답특성을 갖도록 한다. 루엔-버거(Luenberger) 관측기 구조를 이용함으로써 속도정보를 활용한 수직채널 안정화루프의 체계적 설계가 가능함을 보인다. 제안된 설계 방법에 대하여 모의실험을 통해 제안한 기법의 성능 및 유용성을 확인한다.

• Journal of Mechanical Science and Technology
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• 제16권4호
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• pp.454-467
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• 2002

It has been established that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. Toidentifythelocation and depth of a crack in a structure, a method is presented in this paper which uses neuro-fuzzy-evolutionary technique, that is, Adaptive-Network-based Fuzzy Inference System (ANFIS) solved via hybrid learning algorithm (the back-propagation gradient descent and the least-squares method) and Continuous Evolutionary Algorithms (CEAs) solving sir ale objective optimization problems with a continuous function and continuous search space efficiently are unified. With this ANFIS and CEAs, it is possible to formulate the inverse problem. ANFIS is used to obtain the input(the location and depth of a crack) - output(the structural Eigenfrequencies) relation of the structural system. CEAs are used to identify the crack location and depth by minimizing the difference from the measured frequencies. We have tried this new idea on beam structures and the results are promising.