Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 96 === Magnetorheological Fluids, MR-fluids, normally consist of iron powder suspended in some carrier fluids. The viscosity and the yield stress of MR-fluids can be controlled by the applied magnetic filed, thus the main applications of MR-fluids are dampers and breakers. By utilizing the condensation force of the MR-fluids under the influence of the magnetic field, an active linear actuator is designed and developed in this thesis. According to the functional requirement, the design concepts of bladder and diverse magnetic loop are derived. Through the theoretical model and computer assister analysis, the influence of the design and operating parameters on the field strength through the MR-fluids and studied and analyzed. Finally, through the experimental testings, the displacement, the actuation force, and the reaction speed of the MR-actuator are comprehensively inspected and measured. During the pre-actuation phase, the driving current is linearly dependent on the air gap of the magnetic loop. During the actuation phase, MR-actuator can provide a stable push force. The remnant super-strong viscosity situation of the MR-fluids can be relieved by removing the magnetic filed and using compressive spring, which can increase the recovery speed
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