Braking torque control of the multi-disc magnetorheological brake based on the brake pedal

Magnetorheological (MR) transmission technology is an innovation application of the MR effect in the field of engineering transmission. The MR brake with MR fluid as the working medium is a kind of non-contact brake, which has wide application prospects in soft braking systems. The proposed MR braking system uses the MR brake as the braking actuator, but the current-torque relationship of the MR brake shows significant nonlinear hysteresis. In order to achieve a linearized mapping between the input and output of the magnetorheological brake to match with the traditional braking habit of the drivers, the research is carried out to address the problem of the nonlinearity of the excitation current and the output braking torque. The relationship between brake pedal displacement and excitation current is analyzed based on the developed brake pedal simulator. The experimental results indicated that incorporating the brake pedal displacement as a control input for regulating the excitation current can achieve a single-valued linearized mapping of output braking torque and brake pedal displacement. In addition, applying a compensation current to the excitation coil of the MR brake produces a compensation torque, allowing real-time compensation of the output braking torque.