Research on Braking Stability of Electro-mechanical Hybrid Braking System in Electric Vehicles

For the electro-mechanical hybrid braking system, which is composed of electric brake and general friction brake, the models of electric braking force, total braking force and the utilization adhesion coefficient for front and rear axles were established based on the analysis of braking torque distribution. The variation relationship between electric braking force and friction braking force in different braking intensity was calculated and analyzed with the paralleled-hybridized braking control strategy. Taking USA urban driving circle UDDS as an example, the utilization adhesion coefficient of front and rear axles was calculated at different braking intensity for a certain Electric Vehicles (EVs), and the braking stability was also analyzed for front-wheel drive EVs. The calculation results indicate that the utilization adhesion coefficient of front axle is always greater than that of rear axle, which means the front axle always locked ahead of the rear axle, thus the braking stability meets the requirement. The calculation results also have certain instructive significance on the anti-lock braking system (ABS) and electric brake-force distribution (EBD) of EVs.