Electro-hydraulic Series Compound Braking Control for 4WD HEV Using ABS

In order to improve energy efficiency,extend vehicle driving range,and remedy the deficit of motor regenerative braking capacity,aimed at a 4WD hybrid electric vehicle and combining the structure feature of power system with two rear hub motors and an ISG motor,the electro-hydraulic series compound braking system based on anti-lock braking system(ABS)was designed,and close loop control of wheel cylinder pressure was achieved.Considering Economic Commission for Europe regulation(ECE regulation)and regenerative braking constraints,the ideal braking force distribution strategy was designed.Furthermore,in order to deal with the emergency braking condition,the improved self-optimizing theory was used to obtain the optimal ABS slip rate range,and the coordination control strategy of ABS hydraulic brake and motor regenerative braking was developed.The results show that the proposed strategy can make full use of the regenerative braking ability of motors,braking energy can be recovered effectively and safety can be ensured in emergency braking condition.