Hierarchical cooperative control of anti-lock braking and energy regeneration for electromechanical brake-by-wire system

摘要

Energy regeneration during braking process is the key energy-saving technology for electric vehicles (EVs). However, when the anti-lock braking system (ABS) is triggered, it is difficult to coordinate the mechanical braking and regenerative braking to ensure the vehicle stability and maximal energy regeneration. This study proposes a hierarchical cooperative control for the electromechanical brake-by-wire system (EBW) to solve this problem. First, a novel pneumatic EBW is designed. Then, a pneumatic pressure model is built and simplified, based on which a pressure regulation method is proposed. Next, the hierarchical cooperative control is proposed, where top layer controls slip ratio, mid layer distributes braking torque, and bottom layer controls the electric motor torque and pneumatic pressures. Finally, the experiment results show that the proposed strategy achieves better braking safety and energy regeneration performance than mature strategies in products. The research provides an effective solution of cooperative control for EVs, and it can be used as a low-cost approach in other vehicle stability control where precise braking torque is required.