• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.11
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• pp.1046-1051
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• 2010

This paper presents design and performance evaluation of magnetorheological(MR) damper for integrated isolation mount. The MR damper needs two functions for the integrated isolation mount. The one is vibration absorption and the other is isolation of vibration transmission. For vibration absorption, the MR damper requires wide damping force range. And for isolation of vibration transmission, the friction of MR damper needs to be eliminated. In order to achieve this goal, a novel type of MR damper is originally designed in this work. Subsequently, the MR damper is mathematically modeled and its damping force characteristics are evaluated. In addition, the vibration control performance of the MR damper associated with the stage mass is evaluated. From the result, this paper evaluates the performance of MR damper for integrated isolation mount.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.6
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• pp.506-513
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• 2011

This paper is concerned with a study on the control effect of the MR damper using the cutout piston. The MR damper has passive damping force by the oil pressure and controllable damping force by the magnetic effect. As the velocity of the MR damper's piston increases the passive damping force increases and the ratio of the controllable damping force to the total damping force is decreased. Consequently, the control performance of the MR damper is reduced according to the increase of the velocity. In this paper, the cutout piston concept is applied to the MR damper to improve MR damper's control performance by reducing the passive damping effect. The MR damper with the cutout piston has been designed and manufactured and its hydraulic and electromagnetic analysis has been performed to predict its performance. The control performances of the MR damper with the cutout piston are verified through the comparison of experiment results and simulation results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.581-586
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• 2009

This paper presents an optimal design of magnetorheological(MR) damper based on analytical methodology and finite element analysis. The proposed MR damper consists of MR valve and gas chamber. The MR valve is constrained in a specific volume and the optimization problem identifies geometric dimensions of the valve structure that maximize the pressure drop of the MR valve or damping force of the MR damper. In this work, the single-coil annular MR valve structure is considered. After describing the schematic configuration and operating principle of MR valve and damper, a quasi-static model is derived based on Bingham model of MR fluid. The magnetic circuit of the valve and damper is then analyzed by applying the Kirchoff’s law and magnetic flux conservation rule. Based on the quasi-static modeling and the magnetic circuit analysis, the optimization problem of the MR valve and damper is built. The optimal solution of the optimization problem of the MR valve structure constrained in a specific volume is then obtained and compared with the solution obtained from finite element method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.11
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• pp.1110-1118
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• 2009

This paper presents an optimal design of magnetorheological(MR) damper based on analytical methodology and finite element analysis. The proposed MR damper consists of MR valve and gas chamber. The MR valve is constrained in a specific volume and the optimization problem identifies geometric dimensions of the valve structure that maximize the pressure drop of the MR valve or damping force of the MR damper. In this work, the single-coil annular MR valve structure is considered. After describing the schematic configuration and operating principle of MR valve and damper, a quasi-static model is derived based on Bingham model of MR fluid. The magnetic circuit of the valve and damper is then analyzed by applying the Kirchoff' s law and magnetic flux conservation rule. Based on the quasi-static modeling and the magnetic circuit analysis, the optimization problem of the MR valve and damper is built. The optimal solution of the optimization problem of the MR valve structure constrained in a specific volume is then obtained and compared with the solution obtained from finite element method.

• Journal of Aerospace System Engineering
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• v.15 no.1
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• pp.7-18
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• 2021

A semi-active MR damper landing gear is a damper that generates a fluid damping force and a magnetic field control damping force when the MR fluid passes through annular flow paths. In the case of MR fluid passing through annular flow paths, an incompletely developed flow inevitably occurs, causing an error in calculating damper inner forces including the fluid damping force. This error results in an inaccurate design of damper structural parameters and control gain selection, resulting in deterioration of dynamic characteristics and shock absorption performance of the landing gear. In this paper, we derived a mathematical model of an MR damper landing gear considering additional damping force generated in the entrance region of annular flow paths of the MR damper. If the mathematical modeling derived from this paper is applied to the design and optimization process of an MR damper landing gear, excellent performance of the MR damper landing gear is expected.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.511-518
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• 2006

In this study, seismic response mitigation effect of an MR damper generating response-dependent frictional force is investigated. It has been reported in previous studies that passively operated MR damper with constant input current doesn't show better control performance than semi-active MR damper with varying input current calculated by control algorithms such as linear quadratic regulator and sliding mode control. However, in order to operate the MR damper semi-actively, other control systems besides the damper itself such as sensors for measuring structural responses and controller for calculating optimal input current are necessary, which deteriorate the economical efficiency. This study presents a MR damper generating frictional force of which magnitude is controlled in accordance to the displacement and velocity transferred to the damper. Numerical analyses results indicate that the performance of the response dependent MR damper is closely related with the range of the friction force and it can be designed to short better control performance than the passive MR damper.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.6
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• pp.61-69
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• 2013

This research is aimed to evaluate characteristics and dynamic modeling of MR damper for semi-active vibration control. A MR damper of semi-active type was designed and made for the purpose of controlling the vibration of a real-size model structure. Usually a semi-active control system equipped with a MR damper requires a dynamic model which expresses numerical data about the damping capacity and dynamic characteristics generated by a MR damper. To fulfil the requirement, a Power model and a Bingham model were particularly employed among many dynamic models of MR damper. Those models being contrasted with other ones, a dynamic test was carried out on the developed MR damper. In the test, excitation frequencies were conditioned to be 0.15 Hz, 1.0 Hz, and 2.0 Hz, and three different currents were adopted for each frequency. From these test results, it was found that displacement affected control capacity of the MR damper. The test results led to the identification of model variables for each dynamic model, on the basis of which a force-speed relation curve and expected damping force were derived and contrasted to those of the developed MR damper. Therefore, it was proven that the MR damper designed and made in this research was effective as a semi-active controller, and also that displacement of 2mm at minimum was found to be secured for vibration control, through the test using various displacements.

• Journal of Power System Engineering
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• v.15 no.2
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• pp.19-24
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• 2011

In this study, a control method of MR(magneto-rheological) damper for a cruise bus is investigated. A virtual dynamic damper and a sky-hook algorithm are employed to control the damping characteristics of MR damper. Coefficients for a virtual dynamic damper are determined through the parameter identification. A quarter car model of a cruise bus is established by using ADAMS/Car program for the computer simulation. Sine wave excitation and random excitation are used to compare the controlled MR damper with the passive damper. From the simulation results, the performance of MR damper with a virtual dynamic damper is better than that of the passive damper.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.5
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• pp.127-134
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• 2000

This paper presents the development of a semi-active seat damper using MR fluids and the performance analysis of seat suspension system with a MR seat damper. An annular orifice type MR seat damper is proposed for a seat suspension of a commercial vehicle. After formulating the governing equation of motion, then an appropriate size of the seat damper is designed and manufactured. Following the evaluation of field-dependant damping force characteristics, the controllability of the damping force is experimentally demonstrated in time domain by adopting PID controller. A semi-active seat suspension with the proposed MR damper is constructed and its dynamic model is established. Subsequently, vibration control capability of the semi-active suspension system is investigated by employing the sky-hook controller.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.5
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• pp.701-706
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• 2007

Recently, a number of researches about linear magnetorheological(MR) damper using valve-mode characteristics of MR fluid have sufficiently undertaken, but researches about rotary MR damper using shear-mode characteristics of MR fluid are not enough. In this paper, we performed vibration control of shear-mode MR damper for unlimited rotating actuator of mobile robot. Also fuzzy logic based vibration control for shear-mode MR damper is suggested. The parameters, like scaling factor of input/output and center of the triangular membership functions associated with the different linguistic variables, are tuned by genetic algorithm. Simulation results demonstrate the effectiveness of the fuzzy-skyhook controller for vibration control of shear-mode MR damper under impact force.