• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.51-55
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• 1995

본 연구에서는 회전동력전달계의 진동특성을 해석하고 이를 설계자료로 이용하기 위하여, 계 전체의 유효강성행렬 (effective stiffness matrix)을 실험적으로 결정할 수 있는 방법을 제안하였다. 이것은 비교적 측정이 용인한 관성행렬이 알려져 있다고 가정한 경우 기존의 선형 모델링을 그대로 이용하고, 위의 모든 기계요소의 해석이 불가능한 강성들을 포함한 등가강성(equivalent stiffness)으로 구성된 계의 유효강성행렬을, 실험에 의해 얻어진 계의 여러 작동상황과 이에 따른 고유진동수에 매칭(matching)시켜 결정하는 것이다. 또한, 이의 검증을 위하여 유성기어와 클러치로 이루어진 가상의 동력전달계를 구성하고 이의 시뮬레이션 결과를 이용하여, 유효강성 결정법을 통해 얻어진 등가강성들과 실제값들의 비교함으로서 그 신뢰도를 추정하였다.

• Journal of KSNVE
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• v.6 no.2
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• pp.179-185
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• 1996

This paper presents a modeling method for the vibration analysis of a rotating beam the slenderness ratio of which is relatively small. The smaller the slenderness ratio becomes, the larger the shear and rotary inertia effects become. Such effects become critical for the accurate estimation of the natural frequencies and modeshapes, especially higher frequencies and modes, as the angular speed increases. It is also shown that the effects are important for the accurate estimation of the critical angular speed of the beam.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.319-324
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• 2001

Free non-linear vibration of a rotating thin ring with a constant speed is analyzed when the ring has both the in-plane and out-of-plane motions. The geometric non-linearity of displacements is considered by adopting the Lagrange strain theory for the circumferential strain. By using Hamilton's principle, the coupled non-linear partial differential equations are derived, which describe the out-of-plane and in-plane bending, extensional and torsional motions. The natural frequencies are calculated from the linearized equations at various rotational speeds. Finally, the computation results from three non-linear models are compared with those from a linear model. Based on the comparison, this study recommends which model is appropriate to describe the non- linear behavior more precisely.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.713-719
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• 2012

This paper is concerned with the dynamic modeling for the hardware-in-the-loop simulation of lateral vibrations of a railway vehicle. The resulting dynamic model is a nine degree-of-freedom model which can describe the lateral, roll and yaw motions of the car body and two bogies. It is assumed that the external disturbances come from wheel motions. In order to test the efficacy of the model, the linear quadratic regulator and the sky-hook control algorithm were designed and applied to the model. The simulation results show that both control algorithms are effective in suppressing the vibrations of railway vehicles.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.7
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• pp.634-641
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• 2012

This paper is concerned with the dynamic modeling for the hardware-in-the-loop simulation of lateral vibrations of a railway vehicle. The resulting dynamic model is a nine degree-of-freedom model which can describe the lateral, roll and yaw motions of the car body and two bogies. It is assumed that the external disturbances come from wheel motions. In order to test the efficacy of the model, the linear quadratic regulator and the sky-hook control algorithm were designed and applied to the model. The simulation results show that both control algorithms are effective in suppressing the vibrations of railway vehicles.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1813-1814
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• 2008

본 논문에서는 생물학적 운동 메카니즘을 유사하게 구현하기 위해 신경 진동자를 이용한 로봇 팔 제어 시스템을 제안한다. 인간 및 동물의 주기적인 자율 운동을 관장하는 Central Pattern Generator (CPG)를 수학적으로 모델링한 신경 진동자는 그 중요 특성의 하나인 entrainment 효과를 보여준다. 일반적으로 우리는 이 기능을 이용하여 미지의 외부 환경 변화와 같은 외란에 적절히 상호 작용할 수 있는 운동을 생성해 낼 수 있다. 이러한 결과를 보이기 위해, 각 관절에 가상의 신경 진동자 모델을 결합하였고 외부 환경의 변화나 외란의 감지를 위한 F/T센서를 팔의 말단에 부착하여 시스템을 구현하였다. 신경 진동자 모델을 결합한 2축 링크 로봇 팔 시스템(real time)은 주어진 목적운동을 (원 운동) 수행함과 동시에 미지의 외부 환경의 변화(임의의 벽)를 인지하여 적절한 모션을 생성하는 지를 살펴본다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.273-278
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• 2011

This work presents an active vibration control of a stiffened hull structure using a flexible macro fiber composite (MFC) actuator. As first step, the governing equation of the hull structure is derived in a matrix form and its dynamic characteristics such as natural frequency are obtained via a finite element analysis (FEA). The natural frequencies obtained from the FEA are compared with those determined from experimental measurement. After formulating the control model in a state space representation, an optimal controller is designed in order to attenuate the vibration of the stiffened hull structure. The controller is then empirically realized through dSPACE and control responses are evaluated in time domain.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.607-613
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• 2011

In this study, structural vibration analyses for a 5MW offshore wind wind-turbine model have been performed for different substructure models. The efficient equivalent modeling method based on computational multi-body dynamics are applied to the finite element models of the present offshore wind turbines. Monopile and tri-pod substructure types of the typical offshore wind-turbine are considered herein. Detailed finite element modeling concepts and boundary conditions are described and the comparison results for previous analyses are presented in order to show the verification of the present numerical approach. Campbell diagrams are also present to investigate the rotational resonance characteristics of the offshore wind-turbines with different substructures.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.471-474
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• 2011

본 논문에서는 이러한 문제점을 해결하기 위해서 발전기 고정자의 가진 주파수의 거동패턴을 모델링하고 거동패턴의 위상변화를 학습패턴으로 만들어 오류 역전파 알고리즘으로 학습시킴으로써 고정자 권선 단말부에 대한 상태 감시한다. 고정자 모사장치를 구성하고 장치로부터 가진 데이터를 획득하여 실험한 결과 가진 주파수에서 일정한 형태의 거동패턴을 보였으며, 거동을 학습패턴으로 만들어 오류 역전파 알고리즘에 적용한 결과 뛰어난 성능을 보였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.389-391
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• 2014

The Vibration Analysis of Rotating Inward Beams Considering The Tip-Mass is presented based on Euler-Bernoulli beam theory. The frequency equations, which are coupled through gyroscopic coupling terms, are calculated using hybrid deformation variable modeling along with the Rayleigh-Ritz assumed mode methods. In this study, resulting system of ordinary differential equations shows the effects of angular speed, and Young's modulus ratio. It is believed that the results will be a reference with which other researchers and commercial FE analysis program, ANSYS can compare their results.