A low-power magnetorheological fluid clutch utilizing electropermanent magnet arrays

Abstract

In this work, we develop a compact, low-power and partially 3D-printed magnetorheological fluid clutch that operates by variably and reversibly altering the shear stress of the fluid through the local activation of an array of electropermanent magnets (EPMs). By toggling the magnetization of each EPM independently on the order of a few milliseconds, we allow for rapid response times and variable torque transmission without further power input. Selectively polarizing the EPMs for different lengths of time results in repeatable and variable magnetic flux, in turn enabling further control precision. We present the design, modeling, and measured performance of this clutch with various control strategies, and demonstrate its utility as a low-power alternative to more traditional clutch designs.

Study on sedimentation stability of silicone oil-based magnetorheological fluids with fumed silica as additive

“…When the magnetic field is removed, MRFs quickly return to the Newtonian fluid state. MRFs have millisecond response time and good real-time controllability, which makes them suitable for devices controlled by external magnetic fields, such as brakes (Vezys et al, 2018;Acharya et al, 2021), clutches (Akbari et al, 2022;Bira et al, 2022), dampers (Wang et al, 2021;Nordin et al, 2022) and polishing devices (Bai et al, 2019;Milde et al, 2022). However, the density of the magnetic particles is about 7 times bigger than the carrier fluid, the magnetic particles settle in the carrier fluid (Kaide et al, 2020;Su et al, 2020;Maurya and Sarkar, 2021;Zhu et al, 2021).…”