• Title, Summary, Keyword: Magneto-rheological Fluid

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Control of Rotational Angular Speed using Magneto-rheological Fluid (자기유변유체를 이용한 회전 각속력 제어)

  • 신성철;정재성;김정훈;이종원
    • The Korean Journal of Rheology
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    • v.11 no.2
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    • pp.67-72
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    • 1999
  • A magneto-rheological(MR) fluid based rotary loading and braking device is developed. The loading and braking forces of the device are accurately adjustable by controlling the yield stress of MR fluid, so that the vibration control, the precision position control and the speed control of rotating machines equipped with the device can be achieved. As an engineering application, constant rotational speed regulation is conducted using the device manufactured in laboratory, introducing PI control action not only with varying torque due to gravitation, with initial angular speed, but also with constant external torque made by hand. To do this, first, mathematical model was obtained via experiments. And then, simulation was carried out, based on the experimentally identified model. Its result was confirmed through experiment. It is identified by simulation and experimental results that PI action leads to satisfactory control performance in both cases that varying torque due to gravitation, with initial angular speed, and constant external torque are applied.

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Dynamic Characteristics of Magneto-rheological Fluid Actuator for Micro-motion Control (미세동작제어를 위한 자기유변유체 구동기의 동적 특성)

  • Kim, Pyunghwa;Han, Chulhee;Suresh, Kaluvan;Park, Choon-Yong;Shin, Cheol-Soo;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.5
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    • pp.511-517
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    • 2016
  • This paper presents dynamic characteristics of a new actuator using magneto-rheological(MR) fluid between two electrode type coils. The concept of the actuator is to strengthen the force due to the magnetic field produced by the electrode-coil for MR fluid. The amount and direction of current input to the electrode-coils decide the characteristics of contraction-mode and extension-mode. For achieving the required actuating displacement and actuating force, the yield stress of the MR fluid between two electrode-coils is precisely changed by the input current. In this work, the MR fluid is operated in squeeze mode. The experimental results shown in this paper depict that it can be applied in the micro-level displacement and vibration control system.

Vibration Control of a Passenger Vehicle Featuring MR Suspension Units (MR 현가장치를 장착한 승용 차량의 진동제어)

  • 이환수;최승복;이순규
    • Journal of KSNVE
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    • v.11 no.1
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    • pp.41-48
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    • 2001
  • This paper presents vibration control performance of a passenger vehicle featuring magneto-rheological (MR) suspension units. As a first step, a cylindrical shock absorber is designed and manufactured on the basis of Bingham Property of a commercially available MR fluid. After verifying that the damping force of the shock absorber can be controlled by the intensity of magnetic field(or input current), it is applied to a full-car model. An optimal controller is then formulated to effectively suppress unwanted vibration of the vehicle system. The control performances are evaluated via hardware-in-the-loop simulation(HILS), and presented in both time and frequency domains.

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A Study on Design for High-torque MR(Magnetorheological) Brake (MR 브레이크 고출력화 설계에 관한 연구)

  • Park, J.H.;Seo, M.Y.;Lee, H.S.;Ham, Y.B.;Yun, S.N.;Seo, E.S.
    • 유공압시스템학회:학술대회논문집
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    • pp.105-108
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    • 2010
  • In this study, a MR(Magneto-rheological) brake to obtain high torque-to-size ratio instead of conventional powder brake is presented for high-tension control of converting machinery such as coater, slitter and so on. First, to obtain the higher performance than conventional powder brake, a MR brake with a modified rotor shape is newly designed and analyzed by using electromagnetic field analysis. Second, a prototype of the MR brake is fabricated with the optimized structural parameters and an experimental apparatus is constructed. Finally, basic characteristics between current and torque are experimentally investigated.

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Performance Estimation of Magneto-rheological Brake with Different Magnetic Core Shapes (자기 코어 형상에 따른 MR 브레이크의 성능 예측)

  • Park, Jiong Min;Choi, Seung-Bok;Sohn, Jung Woo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.27 no.2
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    • pp.175-181
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    • 2017
  • In the present work, to achieve high braking performance with restricted size, characteristics of magneto-rheological (MR) fluid brake is numerically investigated considering different magnetic core shapes. As a first step, structural configuration of the MR brakes are proposed with four different magnetic core shapes, such as single flat, single inclined, dual flat and dual inclined. To estimate braking performance of the proposed MR brakes, electromagnetic analysis is carried out and the results of magnetic field intensity distribution are observed. Based on the electromagnetic analysis results, braking torque of the MR brake is estimated according to magnitude of current input and results are discussed. It is observed that enhanced braking torque can be achieved by adopting the modified magnetic core shape under limited small size of the MR brake.

Development and Evaluation of a Hybrid Damper for Semi-active Suspension (반능동 현가장치의 하이브리드형 댐퍼 개발에 관한 연구)

  • Jin, Chul Ho;Yoon, Young Won;Lee, Jae Hak
    • Journal of Drive and Control
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    • v.15 no.1
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    • pp.38-49
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    • 2018
  • This research describes the development model and testing of a hybrid damper which can be applicable to a vehicle suspension. The hybrid damper is devised to improve the performance of a conventional passive oil damper using a magneto-rheological (MR) accumulator which consists of a gas accumulator and a MR device. The level of damping is continuously variable by the means of control in the applied current in a MR device fitted to a floating piston which separates the gas and the oil chamber. A simple MR device is used to resist the movement of floating piston. At first a mathematical model which describes all flows within the conventional oil damper is formulated, and then a small MR device is also devised and adopted to a mathematical model to characterize the performance of the device.

An Experimental Study on a Magneto-Rheological Fluid Damper for Structural Control Subject to Base Excitation (지반 기진력을 받는 구조물의 진동제어를 위한 자기유변 감쇠기의 실험적 연구)

  • 김병현;정종안;문석준
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.8
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    • pp.767-773
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    • 2004
  • Semi-active control systems have attracted a great deal of attention in recent years, because they offer the adaptability of active devices without requiring large Power sources. One of the most Promising semi-active devices proposed for structural control is magneto-rheological fluid dampers (MR damper). In this paper, an MR damper having the capacity of about 1 ton was designed and fabricated. and series of tests were performed to grasp the fundamental Performance characteristics of it. It was also applied to a 6-story steel structure under random excitation and 3-different seismic excitations for the confirmation of its validity on structural vibration absorption. Through this study, the techniques and know-hows for MR damper production were acquired.

Design of Magneto-Rheological Clutch Coil Operation Unit using Electro Magnetic Field Analysis (전자기장 해석을 이용한 자기점성 유체 클러치 코일 작동부 설계)

  • Song, Jun-Han;Choi, Dook-Hwan;Chun, Chong-Keun;Kwon, Young-Chul;Lee, Tae-Haeng
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.3
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    • pp.22-28
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    • 2009
  • Recently, there has been an active study about smart fluid to control the vibration, in which MR fluid is evaluated as most efficient because it can generate different bonding forces based on the intensity of the external magnetic fields. This paper attempts to find a mechanism that, under limited conditions during a clutch production that uses such dynamic characteristic, defects the maximum intensity of electromagnetism. Using the finite element analysis program, we predicted a change within the bonding force of the MR fluid occurring inside the clutch when it is subjected to an increased electric current. In addition, we analyzed the change in the magnetic intensity when the coil comprising the coil control center is switched to multiple lines from the standard single line, to find a mechanism that can maximize the effect. Based on this analysis, we developed the clutch and tested its function, hoping to widen future MR fluid's range of application.

Electromagnetic Design and Performance Evaluation of an MR Valve (MR 밸브의 전자기적 설계와 성능평가)

  • Kim, Ki-Han;Nam, Yun-Joo;Park, Myeong-Kwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.3
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    • pp.240-249
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    • 2008
  • This paper presents an electromagnetic design method for magneto-rheological (MR) valves. Since the apparent viscosity of MR fluids is adjusted by applying magnetic fields, the MR valves can control high-level fluid power without any mechanical moving parts. In order to improve the performances of the MR valve, it is important that the magnetic field is effectively supplied to the MR fluid. For the purpose, the magnetic circuit composed with the yoke for forming magnetic flux path, the electromagnetic coil and the MR fluid should be well designed. In order to improve the static characteristic of the MR valve, the length of the magnetic flux path is decreased by removing the unnecessary bulk of the yoke. Also, in order to improve its dynamic and hysteretic characteristics, the magnetic reluctance of the magnetic circuit should be increased by minimizing the cross-sectional area of the yoke through which the magnetic flux passes. After two MR valves, one is a conventional type valve and the other is the proposed one, are designed and fabricated, their performances are evaluated experimentally.