Experimental Evaluation of MR Brake using rollers

Abstract

A generated resistance force in the deformation process is considered to increase the resistance torque of a Magneto- Rheological (MR) brake when a variable stiffness material is rolled under the cylindrical form of a roller. This project proposes a new approach to increase the resistance torque of an MR brake using a large- size magnetic particle which can be considered as the roller mentioned above (steel roller or rolling pin). Due to the tapered cylindrical form of the roller and a line contact between the roller and the surface of the motion part, the steel roller can contribute to create a stronger magnetic field and larger resistance force than the conventional one. In this paper, a new MR brake is successfully designed to generate a higher braking torque than the conventional one, which only uses typical MR fluid. To verify the effect of the roller, the proposed MR brake is compared with the conventional one. Both of the MR brakes are designed with the same magnetic circuit and the same material parameters. The performance of the proposed MR brake is compared with that of the conventional MR brake. MR brake with small steel rollers produces 200% higher braking torque than conventional MR brake. Bingham plastic model describes MR fluid behavior with braking torque up to 13.14 Nm at 2A current. A new approach to designing an MR brake using a small steel roller was proposed, fabricated to verify the performance of the new and the conventional MR brakes in comparison with the same input conditions. From the experimental results, it was verified that the braking torque of the proposed MR brake was 200% larger than that of the conventional one.