Design and Analysis of Miniature Magnetorheological Fluid Device for Handheld Haptic Interface

Magnetorheological (MR) fluids are innovative materials consisting of a suspension of non-colloidal and magnetically polarizable particles in a non-magnetic medium. Their rheological properties change rapidly, stably, and repeatedly when applying magnetic fields. Therefore, MR fluids are used in several engineering applications, such as dampers, brakes, and clutches. Consequently, we focus on the design of a miniature-sized MR device for a lightweight haptic device. To achieve the above goal, we measured and modeled the rheological properties of a sample of SoftMRF. Subsequently, the torque performances of three types of rotor structures were estimated and compared using this model and the results of electromagnetic analyses. In addition, we designed the miniature MR fluid device with lightweight ($\lt60 \mathrm{~g}$) and high torque ($\gt0.2 \mathrm{Nm}$).