• Journal of the Korean Society of Industry Convergence
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• v.6 no.3
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• pp.261-266
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• 2003

이 논문에서는 반능동 진동 흡수기를 통합 시트/섀시 현가 장치에 확대, 적용하여 그 성능을 조사하였다. 통함 현가시스템의 성능분석을 위해 집중 인체질량과 함께 실험적으로 입증된 한 비선형 시트 쿠션 모델을 도입하였다. 또한 3 자유도 시트/섀시 현가시스템의 효과적인 진동제어를 위해 리아푸노브 바이스테이트 제어법칙을 사용하였다. 시뮬레이션결과 반능동 통합 현가장치는 시트 쿠션 모델과 관계없이 운전자의 승차감과 관련 있는 시트의 절대가속도 크기와 시트쿠션의 시트 트랙에 대한 상대변위를 상당히 감소시킬 수 있음을 알 수 있었다. 그러나, 주로 사용되어온 선형 쿠션 모델을 사용한 경우보다 비선형쿠션 모델을 사용한 경우의 제진성능이 약간 저조함을 알 수 있었다. 따라서, 자동차 시트 설계시 성능분석을 위해서는 실제의(비선형의) 시트 쿠션 특성을 적용해야 함을 알 수 있다.

• Coupled systems mechanics
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• v.6 no.2
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• pp.175-187
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• 2017

This paper deals with a uniform cantilever Euler-Bernoulli beam subjected to follower and transversal force at its free end as a model for a pipe conveying fluid under electromagnetic damper force. The electromagnetic damper is composed of a permanent-magnet DC motor, a ball screw and a nut. The main objective of the current work is to reduce the pipe vibration resulting from the fluid velocity and allow it to transform into electric energy. To pursue this goal, the stability and vibration of the beam model was studied using Ritz and Newmark methods. It was observed that increasing the fluid velocity results in a decrease in the motion of the free end of the pipe. The results of simulation showed that the designed semiactive electromagnetic damper controlled by on-off damping control strategy decreased the vibration amplitude of the pipe about 5.9% and regenerated energy nearly 1.9 (mJ/s). It was also revealed that the designed semi-active electromagnetic damper has better performance and more energy regeneration than the passive electromagnetic damper.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.572-577
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• 2005

This paper applies the fuzzy logic controller to a semiactive seat suspension system in order to obtain the better ride comfort in constraint of specific rattle space. The seat suspension system used for this research is a scissors-type one with the MR (Magneto Rheological) fluid damper. Since a seat suspension system with a driver can not be exactly modeled, it is effective to control with the fuzzy logic controller. The rule was carefully tuned to effectively reduce the vibration transmitted to a driver. The on-road ride was realized on a hydraulic excitor and the result shows that the fuzzy controller has reduced the vibration of a seat suspension system compared to the continuous skyhook controller.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.3 s.174
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• pp.691-700
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• 2000

This paper presents a novel type of a semiactive damper featuring an electro-rheological(ER) fluid. Unlike conventional cylindrical ER damper, the proposed one has controllable orifices by the intensity of electric fields (We call it orifice type). The dynamic model of the orifice type ER damper is formulated by incorporating field-dependent Bingham properties of an arabic gum-based ER fluid. Design parameters such as electrode gap are subsequently determined on the basis of the dynamic model. After manufacturing the orifice type ER damper, field-dependent damping forces and damping force controllability are empirically evaluated. In the evaluation procedure, conventional cylindrical ER damper is adopted and its performance characteristics are compared with those of the orifice type ER damper. In addition, the proposed one is installed with a full-car model and its vibration control performance associated with a skyhook controller is investigated.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.7
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• pp.29-38
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• 1997

A closed-loop system modeling of an active/semiactive suspension system has been accomplished through an artificial neural network. A 7DOF full model as a system's equation of motion has been derived and an output feedback linear quadratic regulator has been designed for control purpose. A training set of a sample data has been obtained through a computer simulation. A 7DOF full model with LQR controller simulated under several road conditions such as sinusoidal bumps and rectangular bumps. A general multilayer perceptron neural network is used for dynamic modeling and target outputs are fedback to the a layer. A backpropagation method is used as a training algorithm. Model validation of new dataset have been shown through computer simulations.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.264-271
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• 2006

Stay cables, such as used in cable-stayed bridges, are prone to vibration due to their low inherent damping characteristics. It has been reported that a semiactive control system using MR dampers could potentially achieve both the better performance compared to a passive control system and the adaptability with few of the detractions. However, a control system including a power supply, a controller and sensors is required to improve the control performance of MR dampers. This complicated control system is not effective to most of large civil structures such as long-span bridges and high-rise buildings. This paper proposes a smart damping system which consists of an MR damper and the electromagnetic induction (EMI) part that is considered as an external power source to the MR damper. The control performance of the proposed damping system has been compared with that of the passive-type control systems employing an MR damper and a linear viscous damper.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.505-512
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• 2005

MR damper is one of the most promising control devices for civil engineering applications to earthquake hazard mitigation. However, a control system including a power supply, controller, and sensors is required to maximize the performance of the MR damper and this complicated control system is not effective to most of large civil structures. This paper proposes and experimentally verified a smart passive damping system using MR(Magnetorheological) dampers by introducing electromagnetic induction(EMI) system as an external power source to MR damper. It is easy to build up and maintain EMI system, because it does not require any control system such as a power supply, controller, and sensors. Numerical simulations using experimental model of EMI system are carried to verify the effectiveness of the proposed EMI system. The performances of smart passive damping system are compared with those of passive and semiactive MR dampers.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.3
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• pp.243-250
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• 2002

Semi-active control devices have received significant attention in recent Years because they offer the adaptability of active-control devices without requiring the associated large power sources. Magnetorheological(MR) dampers are semiactive control devices that use MR fluids to produce controllable dampers. This paper applies sliding mode control method using target variation rate of Lyapunov function for the control of structures by use of MR dampers. The three-story building model under earthquake excitation is analyzed by installing a MR damper in the first-story. The performance of semi-active controllers designed by clipped-optimal algorithm and modified sliding mode control algorithm is compared to the performance of passive-type MR dampers. The results indicate that semi-active controllers achieve a greater reduction of responses than passive-type system and especially the controller by modified sliding mode control method shows a good applicability in the view of response control and control force.

• Journal of the Korean Society for Railway
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• v.6 no.4
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• pp.252-256
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• 2003

Smart materials can adapt to changes of environment like living organs in nature such that they can maximize the performance and minimize the maintenance expense of engineering systems. Such materials have been paid attention ten years ago and applied in the area of industry, aerospace, transportation and civil structures. This paper summarizes smart material technology and shows some application examples in railway vehicles. Also, its future of smart material technology in railway vehicle technology is envisaged based on its possibility and practical aspect.

• International Journal of Railway
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• v.3 no.2
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• pp.68-72
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• 2010

Railway vehicles equipped with semi-active suspension system can improve the ride quality of car bodies. Semi-active suspension system is usually applied onto high speed train, and therefore higher running safety requirement is desirable. The influence of semi-active suspension system on safety of vehicles running on straight line and curve line is studied, and the influences of sky hook damping coefficient and system time-delay on operational safety of cars fitted with semiactive suspension system is analyzed. The results show that in vehicles equipped with semi-active suspension system, while the vibration of car body is decreased, the running safety of cars is not affected to any significant degree. As a result, the ride quality is much improved with negligible deterioration of the running safety of cars.