Design, development, and performance evaluation of high-speed magnetorheological brakes

Magnetorheological (MR) fluids change their flow resistance on the application of magnetic field. This variation in resistance to shear, offered by MR fluid, is rapid and almost completely reversible (no hysteresis). This unique feature has motivated authors to design a variable resistance brake using MR fluid. The present paper describes the design procedure of MR brake and discusses the effect of MR gap on its braking torque. Two brakes, Brake 1 with MR gap 1 mm and Brake 2 with MR gap 2 mm have been designed and fabricated. To generate magnetic field one central electro-magnet and two side electromagnets have been suggested. To validate the theoretical design and its findings, prototyping, and experimental study of MR brake have been performed. Vibrating sample magnetometer test has been carried out to obtain magnetic properties of the MR fluid and its magnetic phase. An experimental test setup has been developed to measure the braking torque under various operating speeds (200 to 1200 r/min) and control currents (0.0 to 1.2 A). The effects of central and side electromagnets on braking torque have been examined. The observed results are presented in tabular and graphical form. A close agreement between theoretical and experimental results has been noticed.