Coordinated control of steer-by-wire and brake-by-wire for autonomous emergency braking on split-μ roads

Autonomous emergency braking (AEB) is an active safety technology which aims to prevent collisions by operating harsh braking. When AEB is activated on split-mu roads, the yaw moment generated by the asymmetric braking forces will lead to losing control of the vehicle. In this study, a coordinated control scheme of steer-by-wire (SBW) and brake-by-wire (BBW) is developed to solve this problem. An anti-lock braking system is achieved by a sliding mode controller. Besides, two model predictive controllers based on a 7-degree-of-freedom vehicle dynamics model are proposed for different road adhesion conditions. According to the simulation results, the proposed scheme can maintain the stability of the vehicle and achieve a satisfying braking efficiency under various friction differences between the two-side wheels. At last, the experiments are also carried out to verify the effectiveness and the real-time performance of the proposed scheme on a hardware-in-loop bench of BBW and SBW.