Hua Li

This paper deals with design, simulation and experimental testing of a novel radial multi-pole multi-layer magnetorheological (MR) brake. This MR brake has an innovative structural design with superposition principle of two magnetic fields generated by the inner coils and the outer coils. The MR brake has several media layers of magnetorheological (MR) fluid located between the inner coils and the outer coils, and it can provide higher torque and higher torque density than conventional single-disk or multi-disk or multi-pole single-layer MR brakes can. In this paper, a brief introduction to the structure of the proposed MR brake was given first. Then, theoretical analysis of the magnetic circuit and the braking torque was conducted. In addition, a 3D electromagnetic model of the MR brake was developed to simulate and examine the magnetic flux intensity and corresponding braking torque. A prototype of the brake was fabricated and several tests were carried out to validate its torque capacity. The results show that the proposed MR brake can produce a maximum braking torque of 133 N m and achieve a high torque density of 25.0 kN m ⁻² , a high torque range of 42 and a high torque-to-power ratio of 0.95 N m W ⁻¹ .

In this study, a novel magnetorheological brake with multi-pole and dual-gap configuration is presented to increase not merely the torque output but also the range of controllable transmission torque while maintaining a compact structure. In addition, the proposed magnetorheological brake design features several individual coils, and lower power consumption for a desired torque output could be obtained by properly controlling the input currents in those coils. Theoretical research has been done in order to reveal the relationship between the novel structure and the output torque and obtain the mathematical formulas of the output torque. Then, based on the theoretical research, finite element analysis was performed to optimize the structure, analyze the magnetic field distribution, and evaluate the capability of the designed magnetorheological brake. Finally, an optimization was performed to obtain the minimum power consumption for a desired torque. The results show that the proposed magnetorheological brake can generate a considerable torque density in its dimensions while maintaining controllable power consumption by individual input currents.