Design and experimental evaluation a novel magneto-rheological brake with tooth shaped rotor

In this study, a novel magnetorheological brake (MRB) with tooth-shape rotor is developed. In this new MRB, traditional cylindrical rotor is replaced by a new one with tooth-shaped rotor. The teeth on the rotor act as multiple magnetic poles of the brake. Two magnetic coils are placed on side-housings of the brake to generate a mutual magnetic field of the MRB. The inner face of each side-housing has tooth shaped features as well. These tooth shaped features interact with the rotor teeth via magnetorheological fluid (MRF) medium. By using the tooth shaped rotor, more interface area between the rotor and the working MRF can be archived, which can improve performance characteristics of the proposed MRB such as compact size, low power consumption and high braking torque. After an introduction of state of the art of MRB development, the schematics and working principle of the MRB with tooth-shaped rotor is proposed. The modeling of the MRB is then derived based on magnetic finite element analysis and Bingham rheological model of MRF. Optimal design of the MRB considering mass and braking torque of the MRB is then conducted. From the optimal design result, it is shown that the mass and power consumption of the proposed MRB are significantly smaller than those of previously developed ones. In details, at high value of the maximum braking torque (100 Nm), the proposed MRB mass is only around 31.3% of the mass of the thin-wall single-coil and 42.6% of the mass of the thin-wall double coil MRB. In addition, at small values of the maximum braking torque (5 Nm), power consumption of the proposed MRB is only around 33% of that of the thin-wall single-coil and 45.5% of that of the thin-wall double coil MRB. Experimental works on prototypes of the proposed MRB are then performed for validation.