磁流變液式致動器之設計開發

Design and Development of Magnetorheological Fluid Actuator

林雅凰(Ya-Huang Lin)

指導教授 ： 黃光裕

國立臺灣大學/工學院/機械工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201601188

摘要

磁流變液(Magnetorheological，簡稱MRF)為一種智能液體，主要由載體流體與微小軟磁性顆粒混合而成的懸浮體，可以透過磁場改變其物理特性。在弱磁場作用下，載體流體內的導磁顆粒會被磁化，內部導磁顆粒互相吸引，液體黏滯度和降伏剪應力也大幅提升。當強磁場作用下，液體會順著磁力線排列成針狀結構，本論文將使用此特性，開發設計磁流變液式致動器，主要以控制方形螺旋線圈的電流調整水平方向磁場，使線圈與強力磁石產生的磁場向量合改變，再藉由磁流變液針狀結構推動致動元件，使致動器產生致動力。由於強力磁石所產生的磁場大小為常數，因此由線圈產生的磁場需要為變動磁場，本文使用方波來提供線圈產生所需的變動磁場，也可藉由改變方波的頻率、占空比(duty cycle)來改變移動速度。因此本文以調整線圈電流、頻率、占空比，來量測磁場大小、出力，以及移動速度。本論文實驗不同導磁顆粒體積百分比的磁流變液，分別為MRF-144CG、MRF-132DG和MRF-122-2ED，經由實驗可以發現工作液體為MRF-122-2ED時，在頻率140 Hz且占空比為80%時，致動器有最快移動速度為3.2 mm/s。MRF-144CG、MRF-132DG、MRF-122-2ED三種液體最大出力分別為7.316 mN、7.654 mN、8.366 mN ，因此可得致動器最大出力為8.366 mN。

關鍵字

磁流變液 ； 磁流變液式致動器 ； 針狀結構 ； 驅動電流 ； 磁場向量合

並列摘要

Magnetorheological Fluid, MR-fluid, normally consist of magnetic particles suspended in some carrier fluid. The physical characteristics of MR-fluid can be controlled by the applied magnetic field, thus the usual applications of MR-fluid are breakers and dampers. In weak magnetic field, the magnetic particles of the carrier fluid would have attractive interaction and be magnetization, the viscosity and the yield stress also substantial promotion. In strong magnetic field, MR-fluid would follow the magnetic field lines and become chain formation. By utilizing the characteristics of MR-fluid, magnetorheological fluid actuator is designed and developed in the thesis. The main actuating system is controlling the driving current, could adjustment the magnetic field in horizontal direction of the square helical coil. Through the magnetic field vector changed, which combined by the horizontal magnetic field and the vertical magnetic field of permanent magnet, the chain formation of MR-fluid pushed the actuating component, to make the actuator product the actuation force. Due to the magnetic field of permanent magnet is a constant, the magnetic field of the square helical coil would be varying magnetic field. By exploiting the square wave to offer the signal to the square coil in this thesis, the frequency of square wave, duty cycle could transform the velocity. In this paper, experiment with different volume percentage of magnetic particles of Magnetorheological Fluid, respectively MRF-144CG, MRF-132DG, and MRF-122-2ED. Via experiment, we can found that using MRF-122-2ED as the working fluid, operated at a frequency of 10Hz and duty cycle of 80%, the magnetorheological fluid actuator have the maximum speed for 3.2 mm/s. By experiment we also can found the magnetorheological fluid have the maximum actuator force for 8.4x10-3 N.

並列關鍵字

magnetorheological ； magnetorheological fluid actuator ； chain formation ； driving current ； magnetic field vector

參考文獻

[4]林碩彥，2008，磁黏滯式線性致動器之設計開發與特性研究(Development and Characteristic Study of a Linear Magnetorheological Actuator)，國立台灣大學碩士論文。

[1]Carlson, J. D. and Jolly, M. R., “MR Fluid, Foam and Elastomer Devices”, Mechatronics , Vol. 10, 2000, pp.555-569.

[5]Spencer Jr., B.F. ,Yang, G., Carlson, J.D., and Sain, M.K., “Large-scale MR Fluid Dampers: Modeling and Dynamic Performance Considerations”, Engineering Structures, Vol. 24, 2002, pp.309–323.

[6]Zupan, M., Ashby, M.F., and Fleck, N., “Actuator Classification and Selection—The Development of a Database”, Advanced Engineering Materials , Vol. 4, 2002, No.12, pp.933-940.

[12]Martin, H. and Jing, L., “Chain Formation and Chain Dynamics in a Dilute Magnetorheological Fluid”, Optical Society of America, Vol. 36, 1997,pp. 7664-7671.