• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.932-937
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• 2003

When oil pressure of damper is lost or relative stiffness of spring drops in vibration system, it can be fatally dangerous situation. A fault diagnosis method for vibration system using Support Vector Machine(SVM)is suggested in the paper. SVM is used to classify input data or applied to function regression. System status can be classified by judging input data based on optimal separable hyperplane obtained using SVM which learns normal and abnormal status. It is learned from the relationship of system state variables in term of spring, mass and damper. Normal and abnormal status are learned using phase plane as in put space, then the learned SVM is used to construct algorithm to predict the system status quantitatively

• 소음진동
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• 제10권4호
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• pp.575-583
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• 2000

In this paper, we design a vibration control system that includes a 3-D.O.F. mass-spring-damper structure for the analytical model of a building that is excited at the base of this structure by an external dynamic force, and one Active Mass Damper(AMD) on the top of this structure to generate control forces fro attenuation of the structural response. Two robust controllers based on $\mu$-synthesis and H$\infty$ optimal control are designed for the structural system to show that the performance of a control system can be degraded by some parameter uncertainties such as mass, stiffness coefficients, and/or damping coefficients. The performance of the two controllers are compared in terms of nominal performance, robust stability and robust performance by simulations.

• 한국지능시스템학회논문지
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• 제11권4호
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• pp.347-353
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• 2001

본 논문은 기존의 시간 지연 제어 기법을 이용하여 TSK 모델 퍼지 제어 시스템의 안정화에 적용하는 방법을 제시한다. TSK 모델 퍼지 시스템이 기존의 PDC 방법에 의하여 안정화되어지는 경우 발생하게 되는 LMI 문제를 피하기 위하여 시간 지연 방법에 의한 새로운 안정화 조건이 다루어진다. 제시되어진 방법은 mass-spring-damper 시스템에 적용되어 적용가능성이 평가된다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.343-348
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• 2011

This paper presents ride comfort characteristics of a quarter-vehicle magneto-rheological (MR) suspension system with respect to different tire pressure. As a first step, controllable MR damper is designed and modeled based on both the optimized damping force levels and mechanical dimensions required for a commercial full-size passenger vehicle. Then, a quarter-vehicle suspension system consisting of sprung mass, spring, tire and the MR damper is constructed. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, vertical tire stiffness with respect to different tire pressure is experimentally identified. The skyhook controller is then implemented for the realization of the quarter-vehicle MR suspension system. Finally, the ride comfort analysis with respect to different tire pressure is undertaken in time domain. In addition, a comparative result between controlled and uncontrolled is provided by presenting vertical RMS displacement.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.128-132
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• 1997

This paper deals with the optimization of pipe-support allocation using the genetic algorithm, and shows the feasibility of the optimization method to actual design problems and also the convergence characteristics of optimization calculation with respect to the various seismic waves. The piping system was modeled as mass-spring system with 5 degrees of freedom and the support was as spring-damper. The support allocation problem was formulated to minimize the response of the piping system to seismic excitation.

• 전기전자학회논문지
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• 제7권2호
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• pp.156-165
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• 2003

본 논문은 불확실한 비선형 계통에 대해서 강인한 적응 퍼지 관측기를 설계하는 방법을 제시한다. 새로 제시하는 관측기는 관측기 설계시 관측오차의 동특성식이 SPR (strictly positive real)이어야 한다는 조건이 불필요하다. 또한 불확실한 항에 대한 유계상수도 추정하는 알고리듬을 사용하여 강인항의 이득값을 설계자가 미리 결정할 필요가 없게 된다. 설계된 관측기를 포함한 전체 폐루프 계통에 대해서 리아프노브 안정도를 증명하였으며 관측오차를 포함한 계통의 모든 신호들의 반전역적 유계(semi-global uniform ultimate boundedness)임을 증명하였다. 이론적으로 도출된 결과를 mass-spring-damper 계통에 대한 모의실험을 수행하여 제안된 관측기의 효율성과 성능을 보였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.289-293
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• 1996

Vibration absorber is used to protect the primary system from steady-state harmonic disturbance. By attaching the absorber to the primary system which is modeled as a SDOF system, the new system becomes two DOF system. Depending on the driving frequency on the original system, the absorber needs to be carefully tuned, that is, to choose adequate value of the absorber mass and stiffness, so that the motion of the original mass is a minimum. This paper presents the effects of resonance frequency ratio and of vibration absorber with oil damper and coil spring for linear damped primary systems.

• 한국소음진동공학회논문집
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• 제23권5호
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• pp.463-471
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• 2013

This paper presents design and control of electronic control suspension(ECS) equipped with controllable magnetorheological(MR) damper for passenger vehicle. In order to achieve this goal, a cylindrical type MR fluid damper that satisfies design specification of a middle-sized commercial passenger vehicle is proposed. After manufacturing the MR damper with design parameters, their field-dependent damping forces are experimentally evaluated and compared with those of a conventional damper. A quarter-vehicle MR ECS system consisting of sprung mass, spring, tire, controller and the MR damper is established in order to investigate the ride comfort performances. On the basis of the governing equation of motion of the suspension system, five control strategies(soft, hard, comfort, sport and optimal mode) are formulated. The proposed control strategies are then experimentally realized with the quarter-vehicle MR ECS system. Control performances such as vertical acceleration of the car body and tire deflection are evaluated in frequency domains on random road condition. In addition, performance comparison of WRMS(weighted root mean square) of the quarter-vehicle MR ECS system on random road are undertaken in order to investigate ride comfort characteristics.

• 한국생산제조학회지
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• 제21권1호
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• pp.182-189
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• 2012

This study suggests a dynamic design process for deciding properly design parameters of a mass-spring type Wave Energy Converter (WEC) to achieve sufficient energy conversion from wave to power generator. The WEC mechanism, in this research, consists of a rigid sprung body, a platform, suspension springs and dampers. The rigid sprung body is supported on the platform via springs and dampers and vibrates translationally in the heave direction under wave excitation. At last the resulting heave motion of the sprung body is transmitted to rotating motion of the electric generator by rack and pinion, and transmission gears. For the purpose of vibration analysis, the WEC mechanism has been simply modelled as a mass-spring-damper system under harmonic base excitation. Its maximum displacement transmissibility and steady state response can be determined by using elementary vibration theory if the harmonic ocean wave data were provided. With the vibration analysis results, the suggested dynamic design process of WEC can determine all the design parameters of the WEC mechanism, such as sprung body mass, suspension spring constant, and damping coefficient that can give sufficient relative displacement transmissibility and the associated inertia moment to drive the electric generator and transmission gears.

• 한국소음진동공학회논문집
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• 제26권2호
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• pp.210-216
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• 2016

In this work, performance analysis to improve ride comfort of an ER (electrorheological) fluid damper for a mid-sized passenger vehicle in terms of tire pressure is presented. An ER damper by considering specification for a mid-sized commercial passenger vehicle is proposed and mechanically designed. After manufacturing and assembling the proposed ER damper with design parameters, their performance such as field-dependent damping forces are experimentally measured. A quarter-vehicle ER ECS (Electronic Control Suspension) system consisting of the ER damper, sprung mass, spring, sky-hook controller and tire is constructed to analysis the ride comfort performances. Vertical tire stiffness with different tire pressure is experimentally measured and investigated. In addition, ride comfort analysis such as vertical acceleration root mean square (RMS) of sprung mass is investigated under bump road using quarter-vehicle test equipment.