A New Kind of Braking System Based on a Magnetorheological and Wedge Mechanism

Magneto-rheological (MR) fluid is a kind of intelligent material widely used due to its outstanding properties. In this paper, an MR brake with self-energizing and self-powered capability was modeled, designed and its prototype was developed and tested. It composes mainly of a typical T-shape drum-type MR brake and a wedge mechanism for self-energizing purpose. In addition, a generator was combined to harvest the regenerative energy during braking, which offered the self-powered capability. The brake torque analysis was performed and the braking process was simulated in Matlab/Simulink. Finite element analysis in terms of the magnetic field, temperature field as well as mechanical strength of critical components was carried out. The simulation results were then used to optimize the design parameters and material selection. Finally, a prototype and a corresponding test rig were set up. From the experiment results, only about 27 W power was required for generating 70 N m brake torque, while the regenerative power of the generator could be used for braking, thus fulfilling the self-powered requirement. Different wedge angles were investigated, showing that a larger self-energizing capability could be realized with a smaller wedge angle. This research work presents a promising brake actuator with a relatively small volume, which can significantly enlarge the brake torque while harvesting the brake energy.