• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.170-176
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• 2004

MR dampers show highly nonlinear and histeretic dynamic behavior. Therefore, for a vehicle dynamic simulation with MR dampers, this dynamic characteristics should be accurately reflected in the damper model. In this paper, an artificial neural network technique was developed for modeling MR dampers. This MR damper model was successfully verified through a random input forcing test. This MR damper model can be used for semi-active suspension vehicle dynamics and control simulations with practical accuracy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.899-900
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• 2011

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.3
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• pp.163-169
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• 2016

In the case where a MR-damper is employed for vibration control, it is important to decide on how much control capacity should be assigned to it against structural capacities (strength and load, etc). This paper aims to present a MR-damper's control capacity suitable for the capacities of the structure which needs to be controlled. First, a two span bridge was built equipped with a MR-damper, which constitutes a two-span MR-damper control system. Then, inflicting an earthquake load on the system, a basic experiment was performed for vibration control, and a simulation was also carried out reflecting specific control conditions such as MR-damper and rubber bearing. The comparison of the results against each other proved their validity. Then, in order to calculate an optimal control capacity of the MR-damper, structural capacity was divided into eleven cases in total and simulated. For each case, an additional load of 30 KN was inflicted everytime, thereby increasingly strengthening structural capacity. As a result of the study, it was found that the control capacity of MR-damper of 30 KN was safely secured only with lumped mass of more than 150 KN(case 6). Therefore, it is concluded the MR-damper showed the best performance of control when it exerted its capacity at around 20% of structural capacity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.323-328
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• 2002

The control performance of a vehicle installed with an MR(magnetorheological) fluid-based damper is investigated on the basis of Herschel-Bulkley shear model. Generally, most of MR fluid damper has been analyzed based on a simple Bingham-plastic shear model. However, the Bingham-plastic shear model can not well describe the behavior of the damper on the condition of high velocity and high current field input. Therefore, in this study, the Herschel-Bulkley shear model in which the constant post-yield plastic viscosity in Bingham model is replaced with a power law model dependent on shear rate is used to assess control performance of a vehicle with MR fluid damper suspension system. This study deals with a two-degree-of-freedom suspension using the MR fluid damper for a quarter car model. The response for the bump input to identify the fastness of MR fluid damper embedded skyhook controller and requested magnetic field are investigated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.3
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• pp.249-256
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• 2010

This paper presents performance analysis of a quarter-vehicle magneto-rheological(MR) suspension system with respect to different tire pressure. As a first step, MR damper is designed and manufactured based on the optimized damping force levels and mechanical dimensions required for a commercial mid-sized passenger vehicle. After experimentally evaluating dynamic characteristics of the manufactured MR damper, the quarter-vehicle MR suspension system consisting of sprung mass, spring, tire and the MR damper is constructed in order to investigate the ride comfort. 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 quarter-vehicle MR suspension system. Ride comfort characteristics such as vertical acceleration RMS and weighted RMS of sprung mass are evaluated under various road conditions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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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.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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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.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.2 s.42
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• pp.7-15
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• 2005

Numerical analysis model is proposed to predict the dynamic behavior of a single-degree-of-freedom structure that is equipped with hybrid base isolation system. Hybrid base isolation system is composed of friction pendulum systems (FPS) and a magnetorheological (MR) damper. A neuro-fuzzy model is used to represent dynamic behavior of the MR damper. Fuzzy model of the MR damper is trained by ANFIS (Adaptive Neuro-Fuzzy Inference System) using various displacement, velocity, and voltage combinations that are obtained from a series of performance tests. Modelling of the FPS is carried out with a nonlinear analytical equation that is derived in this study and neuro-fuzzy training. Fuzzy logic controller is employed to control the command voltage that is sent to MR damper. The dynamic responses of experimental structure subjected to various earthquake excitations are compared with numerically simulated results using neuro-fuzzy modeling method. Numerical simulation using neuro-fuzzy models of the MR damper and FPS predict response of the hybrid base isolation system very well.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.3
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• pp.73-82
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• 2008

Recently MR CDC damper has been applied to semi-active suspension control system gradually. Compared to former hydraulic CDC damper, it has rapid time response performance as well as simple internal structure and wide range of damping force. In order to develop control logic algorithm which enables to take maximum advantage of unique characteristics of MR CDC damper, it is inevitable to perform a thorough investigation into its nonlinear performance. In many previous researches, MR fluid model was either simply assumed as Bingham Plastic, or a phenomenological model based on experiment was established instead to predict damping performance of MR CDC damper. These experimental flow model which is not based on flow analysis but intentionally built to fit damping characteristics, may lead to totally different results in case of different configuration or structure of MR CDC damper. In this study, a generalized flow formula from mathematical flow model of MR fluid for annular orifice is derived to analyze and predict damping characteristics when current is excited at piston valve.

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.3
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• pp.143-150
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• 2013

The paper introduces Multi-Platform Analysis (MPA) for the seismic performance of a structure controlled by Magneto-Rheological (MR) dampers and presents analytical assessment of the effect of MR damper when taking into account nonlinear behavior of the structure. This paper introduces the MR Damper Plugin that can facilitate communication between MATLAB/Simulink and a finite element analysis tool in order to account for more complex inelastic behavior of the structure with MR dampers. The MPA method using the developed MR Damper Plugin is validated with experimental results from the real-time hybrid simulation. By utilizing the proposed MPA method, the three-story RC structure controlled by MR dampers is more realistically modeled and its performance under seismic loads is investigated. It is concluded that MR damper designed for a linear structure is not effective in a nonlinear structure and can overestimate the effect of MR damper. This work is expected to overcome difficulties in the analytical assessment of structural control strategies for complex and nonlinear structures by obtaining more reliable results.