• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.3
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• pp.284-290
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• 2012

In this research, a new type of haptic master device using electrorheological(ER) fluid for minimally invasive surgery(MIS) is devised and control performance of the proposed haptic master is evaluated. The proposed haptic master consists of ER bi-directional clutch/brake for 2 DOF rotational motion(X, Y) using gimbal structure and ER brake on the gripper for 1 DOF rotational motion (Z). Using Bingham characteristic of ER fluid and geometrical constraints, principal design variables of the haptic master are determined. Then, the generation of torque of the proposed master is experimentally evaluated as a function of applied field of voltage. A sliding mode controller which is robust to uncertainties is then designed and empirically realized. It has been demonstrated via experiment that the proposed haptic master associated with the controller can be effectively applied to MIS in real field conditions.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09b
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• pp.137-140
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• 2003

2관성 공진계는 전동기와 부하 사이에 탄성이 있는 동력 전달 체계를 포함하는 시스템으로 고속 제어시 진동이 발생된다. 이와 같은 2관성 공진계에 대해 궁극적인 출력이 되는 부하의 위치 및 속도는 측정하기가 어렵다. 이에 기존의 연구들은 추정기등을 이용하여 부하의 속도를 추정하여 이를 제어에 활용하는 방식으로 구성되어진다. 그러나 이와 같이 추정기를 사용하기 위해서는 정확한 모델이 필요하다. 본 논문에서는 다소 부정확 모델에 대해서도 매우 정교한 제어 성능을 갖는 반복 학습 제어를 이용하여 2관성 공진계의 위치 제어를 시도하고자 한다. 제시된 방법은 2관성 공진계에 대한 모델링이 정확하지 않더라도 진동 없이 정확한 위치 제어가 가능하다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.73-79
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• 1996

우리나라와 같이 철도의 운행위치와 소음 피해를 받는 수음자 간의 거리가 인접되어 있는 경우, 소음의 전파특성은 과도형상을 나타내는 구간에 속하게 되어 전파중에 나타나는 지표면의 다양한 물리적, 현상과 경계면 등의 이피던스 값등이 많은 영향을 끼치게 된다. 본 연구에서는 철도소음의 소음원 자체에 대한 모델링 기법과, 자유공간을 전파할 때 나타나는 거리감쇠 효과 등을 고려한 음향학적인 연속선음원 및 유한 불연속 선음원 등에 대한 검토가 이루어졌고, 특히, 소음원의 크기에 비교하여 수음자의 위치에 따라 저감되는 음향전파특성을 설명하였다. 또한, 유한한 길이를 가지고 있는 철도차량의 소음원 모델을 이용하여 향후 국내에서 운행되리라 예상되는 고속철도의 음향파워를 산출하였다. 산출된 음향파워로부터 철도변의 소음분포를 도출하였으며 고속철도의 경우 운행시 소음피해가 어느 정도인지를 예상하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.335-341
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• 1996

유한차분 감소를 이용한 감도해석 및 구조변경 프로그램을 개발하고 수치해석을 수행하여 다음과 같은 결론을 얻었다. 1) 유한요소 모델로부터 얻은 유한차분감도를 이용한 결과가 미분을 이용한 감도해석법의 결과에 비해 큰 차이없이 타당한 결과를 제시하여 주는 것을 확인하였다. 2) 복잡한 판구조물의 형상을 등가의 동특성을 갖는 보를 이용하여 모델링하고, 보의 단면치수를 설계변수로하여, 구조변경을 수행함으로써 효율적인 해석을 수행하였다. 3) 혀상이 복잡한 판 구조물의 형상 및 치수등 비선형적인 요소의 변경으로 인한 구조변경시 유한차분 감도 해석법을 이용한 구조변경이 좋은 결과를 나타내는 것을 확인하였고, 이로써 유한차분을 이용한 감도해석법이 형상최적화(shape optimization)에 적합한 방법임을 알 수 있었다.

• Journal of KSNVE
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• v.6 no.3
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• pp.305-315
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• 1996

Present paper aims at the correlation of modal characteristics of folding fin between test and analysis using an optimization theory. Folding fin is composed of a movable fin, a base fin, and many functional components related to the folding mechanism. Joint parts of folding fin in FEM are initially modeled as rigid elements resulting some difference between test and analysis in modal characteristics. Therefore, some equivalent springs representing joint parts are introduced to improve the FEM model. The springs were set as design variables, while the frequency difference between test and analysis was set as the object function. Bayesian procedure was ujsed for the minimization.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.824-828
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• 2007

In this paper Statistical Energy Analysis has been considered to predict middle, high frequency air borne interior noise. PIM method is used for verification. Damping loss factor and coupling loss factor have been derived from the response(SPL) of sub systems when the power is applied. The airborne SEA model of vehicle is modeled through AutoSea2. Insulation material's absorption coefficient and transmission loss are acquired from closed form solution and experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.875-879
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• 2007

The effects of the statistical properties of the Coulomb friction coefficients on the dynamic responses of a galloping quadruped robot are investigated in this paper. In general, the Coulomb friction coefficients are assumed to be deterministic for a controller design to achieve required motion characteristics. However, the friction coefficients between the ground and the robot legs are not constant in reality. Therefore, statistical characteristics of the friction coefficients need to be considered for a multi-body modeling of the robot galloping on the ground. The effects of the statistical properties on the dynamic responses of the quadruped robots are investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.101-104
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• 2007

All of noise prediction model have it's own features in the case of modeling conditions, so it is very important to know the features of each model case by case for a proper modeling, especially using at the Environmental Impact Assessment. For prediction of highway traffic noise and abating the noise by barriers, two kinds of prediction model, HW-NOISE, KHTN(Korea Highway Traffic Noise) has been mainly used in Korea. In this study, the features of these models were described at the same conditions. The properties of sound power from a road, diffraction characteristics from a barrier, sound pressure level decaying in each model were investigated. Using the results, it will be anticipated that the proper using of prediction models in the works of highway noise abating.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1153-1159
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• 2007

The vibration analysis is necessary at the design stage to improve crew's life on board and to prevent the vibration troubles of the hull structures and main machineries prior to the construction. Especially, if high vibration problems occur on the global structures like the hull girder and the deckhouse after construction, it takes lots of time, labor and cost to cure them and thus accurate analysis of global vibration should be performed from the design stage. In this study, some factors for the global vibration analysis have been investigated and the way to be applied to the analysis has been suggested.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.646-649
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• 2008

This study deals with mechanism of relay operation and modeling of transfer function between impact force and sound pressure due to the impact force in order to reduce relay noise. A collision between a moving-contact and fix-contact produces impact noise. Therefore impact noise of relay is determined by not only excitation force but also transfer function from impact force to noise. In this study, we find mechanism of relay operation, make impact force model and measure characteristic of relay noise. And also we find transfer function of relay noise.