• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.382-387
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• 2012

This paper presents a proof-of-concept study on the evaluation of torsional vibration isolation performance through in-situ output torque measurement by using a non-contacting magneto-elastic torque transducer installed in the vehicle driveline system. The de-trending processing is first conducted to extract the torsional vibration from the measured driveline output torque. In order to estimate the transmissibility, primary performance indicator of a vibration isolator, the magnitude of transmitted torsional vibration with different frequencies is compared. From the conservative estimation results, the torsional damper built in a lock-up clutch of a torque converter is identified to be a vibration isolator. The evaluation results show that the fluid damping by torque converter outperforms the vibration isolation function of a torsional damper, and the isolation performance needs to be enhanced.

• 한국소음진동공학회논문집
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• 제21권12호
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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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.381-386
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• 2007

This paper presents vibration control performances of a commercial magnetorheological (MR) suspension via new control strategy considering hysteresis of the field-dependent damping force of MR damper. A commercial MR damper which is applicable to high class passenger vehicle is adopted and its field-dependent damping force is experimentally evaluated. Preisach hysteresis model for the MR damper is identified using experimental first order descending (FOD) curves. Then, a feed-forward compensation strategy for the MR damper is formulated and integrated with a linear quadratic regulation (LQR) feedback controller for the suspension system. Control performances of the proposed control strategy for the MR suspension is experimentally evaluated with quarter vehicle test facility.

• 한국소음진동공학회논문집
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• 제18권3호
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• pp.315-322
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• 2008

This paper presents vibration control performances of a commercial magnetorheological(MR) suspension via new control strategy considering hysteresis of the field-dependent damping force of MR damper. A commercial MR damper which is applicable to high class passenger vehicle is adopted and its field-dependent damping force is experimentally evaluated. Preisach hysteresis model for the MR damper is identified using experimental first order descending(FOD) curves. Then, a feed-forward compensation strategy for the MR damper is formulated and integrated with a linear quadratic regulation(LQR) feedback controller for the suspension system. Control performances of the proposed control strategy for the MR suspension is experimentally evaluated with quarter vehicle test facility.

• 한국소음진동공학회논문집
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• 제14권5호
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• pp.377-384
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• 2004

An Amplitude Proportional Friction Damper (APFD), in which the friction force is proportional to the system displacement, has been introduced and mathematically modeled. To understand the damping characteristics of APFD, analytical solutions for the impulse response has been derivedand compared to the viscous damper. It is found that APFD system has very similar damping characteristics to viscous damper even though it is a friction damper. APFD may be used as a cost-effective substitution for the viscous damper and could also be used to improve the simple friction or Coulomb dampersince APFD works with no stick-slip and always returns to original position when external disturbance is disappeared.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.691-692
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• 2012

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.668-669
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• 2010

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.282-286
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• 2000

In this paper, magneto-rheological(MR) damper is studied for vibration control of large infra structures under earthquake. Generally, active control devices need a large control force and a high power supply system to reduce the vibration effectively. Large and miss tuned control force may induce the dangerous situation such that the generated large control force acts to amplify the structural vibration. Recently, to overcome the weaknesses of the active control, the semi-active control method is suggested by many researchers. Semi-active control uses the passive control device of which the characteristics can be modified. Control force of the semi-active device is not generated from the actuator with power supply. It is generated as a dynamic reaction force of the device same as in the passive control case, so the control system is inherently stable and robust. Unlike the case of passive control, control force of semi-active control is adjusted depending on the measured response of the structure, so the vibration can be reduced more effectively against various unknown environmental loads. Magneto-rheological(MR) damper is one of the semi-active devices. Dynamic characteristics of the MR material can be changed by applying the magnetic fields. So the control of MR damper needs only small power. Response time of MR to the input voltage is very short, so the high performance control is possible. MR damper has a high force capacity so it is adequate to the vibration control of large infra structure. Because MR damper has a nonlinear property, normal control method used in active control may not be effective. Clipped optimal control, modified bang-bang control etc. have been suggested to MR damper by many researchers. In this study, sliding mode fuzzy control(SMFC) is applied to MR damper. Genetic algorithm is used for the controller tuning. To verify the applicability of MR damper and suggested algorithm, numerical simulation on the aseismic control is carried out. Simulation model is three-story building structure, which was used in the paper of Dyke, et al. The control performance is compared with clipped optimal control. The present results indicate that the SMFC algorithm can reduce the earthquake-induced vibration very effectively.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.98-102
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• 2009

The magneto-rheological fluid expresses different cohesiveness according to the strength of the external electric current. To manufacture the magneto-rheological fluid damper that uses such characteristics of the fluid, a flow analysis of the inner damper was conducted to forecast the damper's capacity. In addition, using the finite element method software, analysis on the characteristics of electromagnetic field around the coil operation unit inside the damper. Based on the result of the analysis, a single core damper and a double core damper were built and tested for their dynamic function. Based on the result of the experiment, the propriety of the flow analysis was demonstrated, and the proposed model was verified.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.986-990
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• 2002

Dual Mass Flywheel(DMF) is used in order to improve the vibration characteristics of drivetrain of manual transmission vehicles. Regardless of its complexity and high cost, application of DMF is keep increasing due to a trend of using Diesel engines in passenger cars and light weight design of drivetrains. Modeling and analysis of DMF is rather simple, but finding out optimum parameters of damper may not be easy. Furthermore, its realization in DMF has some limitations due to DMF's structure and its structure dependent damping characteristics. Requirements on spring-damper characteristics of DMF has been reviewed and investigations on structures and damping characteristics of currently Produced DMFs have been made in this paper. Also, ideal spring and damper characteristics has been proposed based on such investigations.