Hybrid Magnetorheological Brake with Electromagnet and Permanent Magnet for Energy Efficient Controlled Braking

Magnetorheological brakes (MRBs) use field-sensitive magnetorheological fluids (MRFs) to provide fast and controllable braking, but conventional electromagnet (EM)-based designs suffer from high power use, heat generation, and limited torque density, which limit their practical efficiency. These limitations highlight the need for improved MRB designs that enhance performance while reducing energy use and heat, as current studies have not fully achieved a balanced improvement in magnetic efficiency and thermal stability within a single system. To overcome these challenges, this study proposes a hybrid dual-disk MRB incorporating a segmented Halbach configuration of six permanent magnets (PMs) and six electromagnets. This design aims to improve magnetic-field distribution and overall system efficiency. Finite-element analysis shows that the proposed configuration effectively concentrates magnetic flux within the MR gap while reducing leakage, achieving a peak flux density of 0.78 T, approximately 55% higher than conventional EM-only designs. The system delivers a maximum braking torque of 16.93 Nm at 2 A, with a high torque-to-volume ratio. In general, the proposed hybrid Halbach MRB improves energy efficiency and thermal behavior while providing faster response and stable performance, with an essential fail-safe capability due to zero-field torque, making it suitable for advanced braking and actuation applications.