Investigation of magnetorheological brake with rotor of combined magnetic and non-magnetic materials

Abstract

Magnetorheological (MR) brakes are a type of electromagnetic brakes that make use of controllable viscoelastic properties of magnetorheological fluid for braking. The torque capacity of the MR brake depends on the magnitude of magnetic flux density generated in the MR fluid. In this study, the effect of combination of magnetic and non-magnetic materials for rotor disk of MR brake with the objective to maximizing the flux density in the MR fluid gap at the rotor periphery was investigated. Initially, the MR brake rotor disk radius and MR fluid gap thickness were determined by using Genetic Algorithm optimization technique for desired torque ratio and torque capacity. Magnetostatic analyses were performed at different current magnitudes to determine the magnetic field and flux density in the MR brake. Further, to enhance the magnetic field intensity in the MR fluid at the rotor periphery, the rotor was modeled with three different configurations of MR brake with combinations of magnetic and non-magnetic steel and magnetostatic analyses of the MR brake were performed. It was found that the leakage of flux away from rotor periphery was reduced and there is significant increase and concentration of the magnetic field and flux density in the MR fluid gap through the use of rotor disk with combined magnetic and non-magnetic materials which would subsequently increase the torque capacity of the MR brake.

Selection of optimal composition of MR fluid for a brake designed using MOGA optimization coupled with magnetic FEA analysis

“…The design of MR brake should ensure maximization of magnetic field strength in MRF gap and avoid magnetic saturation in the core which would result in higher field induced braking torque. (Acharya and Kumar, 2019; Zhang et al, 2006). Optimal dimensions of disc, cylindrical, inverted drum and T-shaped MR brakes with single and double coils were determined by Nguyen and Choi (2012b) intended for maximization of braking torque with torque ratio constrained to be more than required value.…”