Braking force dynamic coordinated control for hybrid electric vehicles

The possibility of regenerative braking is one inherent advantage of hybrid electric vehicle. The motor and the hydraulic braking system are braking together while the hybrid electric vehicle is braking. But, the difference of the braking force dynamic response between the motor and the hydraulic braking system will lead the inadequate or excessive braking and will effect the braking felling of the driver. In this paper, we analyze the braking dynamic characteristics of the motor and the hydraulic braking system. Then, we analyze the hybrid electric vehicle working patterns of the braking process and design the hierarchical structure of the braking force control system. After that, we propose the braking force coordinated control strategy based on using the hydraulic braking force to compensate the motor braking force during the braking process of the hybrid electric vehicle. This paper used the integrated feed-forward and feedback control to design the braking force coordinated control strategy. This integrated control can maintain the stability of the control system while reduce the system error and increase the dynamic performance of the system. The simulation results show that braking force dynamic coordinated control is effective and the total braking force can meet the desired braking force during the braking of the hybrid electric vehicle.