Torque Characteristics Analysis of a Magnetorheological Brake with Double Brake Disc

Magnetorheological (MR) brake is a sort of electromagnetic brake that uses the controllable output characteristics of MR fluid for braking. In this paper, an MR brake with a double brake disc was developed to improve the braking performance of conventional MR brakes. The effective damping gaps were increased from the traditional two sections to four sections by increasing the single brake disc of the conventional MR brake to a double brake disc. By reasonably arranging the non-magnetic sleeve inside the MR brake, the magnetic flux lines were better guided to the effective damping gaps, which increased the utilization rate of the magnetic field, effectively enhanced the braking performance, and also reduced the braking power consumption. The structure and working principle of the MR brake with double brake disc were discussed. The magnetic field of the proposed MR brake was analyzed by ANSYS software, and the theoretical result of braking performance was obtained by combining the established mechanical model. The braking performance test rig was setup to investigate the torque performance of the MR brake. The experimental results show that the maximum braking torque is 18.01 N center dot m at the applied current of 2.0 A and the rotational speed of 400 r center dot min(-1), and the simulation values are basically verified. In addition, the results indicate that the constant torque characteristic of the MR brake is relatively stable, and the torque is almost unaffected by the changes of rotational speed. The results can provide some guidance for the structural design and optimization of the MR actuators.