Coordination control on the electro-hydraulic braking system of electric vehicles

To make electro-hydraulic braking systems table in electric vehicles (EV), this paper presents a coordination control strategy between motor braking system (MBS) and hydraulic braking system (HBS), including braking mode switching strategy and coordination control strategy of the braking force. The distribution strategy between motor braking force (MBF) and hydraulic braking force (HBF) is based upon demanding braking torque (DBT), consideration of the battery SOC, vehicle braking strength and the road adhesion coefficient. The developed models and the control algorithms are programmed by using Matlab/ Simulink and with AVL-Cruise software platform established EV electric-hydraulic braking system simulation model and perform simulation research of braking stability in different kind of roads, and different braking intensity. Simulation result shows that: during low-intensity braking, MBS can meet the needs of the vehicle, and the HBS does not work; during moderate braking process, the MBS and HBS work coordinately, and the braking process is stable; during high-intensity braking process or high battery SOC, MBS doesn't work and the HBS provides the sole braking force. Therefore, the coordination braking control strategy can ensure the stability of vehicle during the braking process.