• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.6
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• pp.557-567
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• 2015

The most decisive factor of major sources of a helicopter is the main rotor system and the rotor-induced vibration is one of the technical challenges which should be resolved to ensure comfort for crews and passengers. Passive vibration reduction devices are adopted in conventional helicopters and several types of passive devices are also used in Surion. In recent years, foreign helicopter manufactures have increasingly applied the application of AVCS (active vibration control system) because of their superior performance with lower weight compared to passive device. In addition to weight reduction, AVCS has advantages maintaining its performance over aircraft configuration changes and flight condition changes. The technology demonstration program was performed in order to validate the performance of AVCS when applied to Surion, and optimization process for finding optimal configuration of sensors and actuators. Optimal configuration was produced using ground and flight test data, and its performance was evaluated and compared with flight test result.

• Explosives and Blasting
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• v.26 no.2
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• pp.92-98
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• 2008

Measuring methods of the blasting vibration were generally divided the. manual method and the automatical method. When using the automatical method, field data of the vibration meter can be transferred to a operation computer by using remote equipments. In this study new automatical system using solar power supply is to be introduced. New automatical system is well suited for the field which is difficult to access and is needed frequent measurements of the blasting vibration. And it can make easy to accumulate the data and control the blasting vibration for safe blasting.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.387-392
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• 2013

본 연구에서는 천음속 전투기 무장창 내부의 압력 진동을 제어하기 위해 F-111의 무장창을 2차원 공동(Cavity)으로 모델링하고, EDISON_전산열유체 시스템을 활용하여 공동의 형상 변화에 따라 발생하는 유동 특성을 분석하였다. 최근의 전투기들은 항력 감소와 스텔스 기능을 위해 무기를 기체 안에 내장하는데, 덮개를 열 때 발생하는 공동 형상에 의해 강한 압력 진동이 유발된다. 이러한 진동은 무장창과 주변 기계 장치에 구조적 진동을 일으키고 고장 또는 파괴를 유발하므로, 근본적인 해결책이 필요한 중요한 문제이다. 본 연구에서는 진동의 원인이 되는 전단층(Shear layer) 불안정성을 해결하기 위해 기존에 연구된 형상(Leading edge extension 및 Ramp)과 본 연구에서 새로 제안한 Ramp extension을 적용해 보았다. 그 결과 압력 진동의 원인이 되는 유동 특성이 줄어들고 압력 진동 역시 감소했음을 관찰할 수 있었다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.4
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• pp.391-397
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• 2016

Vibration disturbances induced by the reaction wheels can severely degrade the performance of high precision payloads on board satellites with high pointing stability requirements. The unwanted disturbances produced by the reaction wheels are composed of fundamental harmonic disturbances due to the flywheel imbalance and sub/higher harmonic disturbances due to bearing irregularities, motor imperfections and so on. Because the wheel speed is constantly changed during the operation of a reaction wheel, the vibration disturbance induced by the reaction wheels can magnify the satellite vibration when the rotating frequency of wheel meets the natural frequency of satellite structure. In order to provide an effective isolation of the reaction wheel disturbances, isolation performance of a hybrid vibration isolator is investigated. In this paper, hybrid vibration isolator that combines passive and active components is developed and its hybrid isolation performance using notch filter control is evaluated in single-axis. The hybrid isolation performance using notch filter control show additional performance improvement compared to the results using only passive components.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.107-109
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• 2019

본 논문에서는 직류 마이크로그리드의 버스 전압 진동을 감쇠하기 위한 에너지 저장장치의 제어기법을 제시한다. IDA-PBC 이론을 이용한 제어기를 설계하고, 직류 마이크로그리드의 안정도를 해석한다. PSIM 시뮬레이션을 이용하여 제안하는 기법의 타당성을 검증하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1199-1205
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• 2011

In the present work, a seat suspension system adopting semi-active damper is evaluated for driver's ride quality. A cylindrical type of ER(electrorheological) damper is designed and manufactured for the seat suspension of heavy vehicles. The governing equation is derived under consideration of human vibration. A sliding mode controller is then synthesized and experimentally realized on the manufactured ER seat suspension while a driver is sitting on the controlled seat. Ride quality is evaluated by fatigue decreased proficiency boundary, vibration dose value and crest factor utilizing weighted-acceleration according to ISO2631.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1153-1158
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• 2010

In this paper, We make horizontal balancer (HB) and confirm a possibility of the technique that can be applied to ship through horizontal vibration reduction experiment. We use MATLAB as the simulator tool and experimental equipment consists of two induction motors shafts of which cam type unbalanced loads are fixed to, DSP and inverter circuit. Two induction motors perform roles as vibrator and balancer respectively, DSP control softwares such as speed, phase and vector control program. The simulation and experimental results show that the balancer characterizes good vibration reduction by phase control.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.162-163
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• 2009

본 연구에서는 초음파 진동자를 적용한 초극세사 자동 절단 시스템을 개발 하였다. 초극세사 자동 절단 시스템은 공진 주파수 28kHz를 가지는 초음파 진동자, 구동회로부, 원단 이송장치, 초음파 진동자 이송장치, 초극세사 원단과 에어실린더 사이의 정전기 발생을 방지하기 위한 정전기 제거장치, 구동모터, 및 절단 크기와 절단 속도 등을 조절하기 위한 전기제어 판넬로 구성하여 제작하였다. 또한, 개발한 절단 시스템을 이용하여 초극세사 클리너 시제품을 제작하여 절단면을 전자현미경으로 관찰하였고, 절단 시스템의 소음진동 특성을 평가하였다.

• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.325-331
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• 2007

This paper proposed modelling and design method in suspension system design to analyze active suspension equipment by adopting active robust control theory. Recent in the field of suspension system design it is general to adopt active control scheme for stiffness and damping, and connection with other vehicle stability control equipment is also intricate, it is required for control system scheme to design more robust, higher response and precision control equipment. It is known that active suspension system is better than passive spring-damper system in designing suspension equipment. We analyze suspension system with considering location of front-rear wheel and driving velocity, then design control system. Numerical example is shown for validity of robust control system design in active suspension system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1991.04a
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• pp.175-181
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• 1991

정밀장비의 진동환경을 평가, 제어하기 위해서는 우선적으로 미진동 환경을 측정할 수 있는 장비와 기술이 필요하며, 방진 system 구성시 국내에서는 방진소재의 개발이 요구되고 있다. 그리고 진동에 민감한 정밀장비들을 사용 하는 반도체 및 정밀공장에서는 진동허용 기준을 나타내는 data sheet가 필 요하고 사용자측에서도 장비의 진동 test성적서를 장비구매시 제작사에 요구 할 필요성이 있다. TEM(투과형 전자현미경)의 경우 음압에 의한 가진문제도 대두되고 있으며 정밀장비가 최대의 성능을 발휘하기 위해서는 이러한 문제 를 검토해야 한다. 만일 국내에서 진동에 민감한 정밀장비를 제작시 장비의 진동 특성을 평가할 수 있는 실험장치와 기술이 필요하다.