Performance Analysis of Electronic Mechanical Assisted Braking of Environmental-Friendly Vehicles Based on Pedal Decoupling

Abstract

This research aims to reduce the impact of the regenerative braking force generated by the new energy vehicle on the braking performance during regenerative braking. It mainly focuses on the braking design scheme of pedal decoupling and the corresponding pedal decoupling strategy. First, the pedal decoupling scheme is designed, and the electronic mechanical assisted braking model and the overall model of the driving vehicle are established. The model includes electromechanical booster model, active accumulator model, and hydraulic braking model. The electromechanical booster model mainly includes the permanent magnet synchronous motor model and the transmission mechanism model. Then, the pedal decoupling strategy based on the new decoupling scheme is studied, and the decoupling process is divided into three stages. According to the control requirements of each stage, the control of pressure reducing valve and the pump motor in the electronic stability program (ESP) is realized, so as to adjust the brake circuit hydraulic pressure during the decoupling process. Moreover, the decoupling current is calculated to adjust the torque of the electromechanical booster motor, so as to adjust the pedal feel. Finally, the control strategy of the electro-mechanical assist motor is designed to realize the control of the motor. The experimental results show that the designed decoupling strategy can make the master cylinder hydraulic pressure change according to the distribution result of the braking force distribution strategy under the three braking strengths of low, medium, and high, which has a good decoupling effect. In addition, the decoupling electro-hydraulic compound braking realizes the precise control of the wheel cylinder pressure and effectively recovers the braking energy. The braking energy feedback efficiency reaches 54.8%. The designed decoupling strategy provides some references for the adoption of pedal decoupling in automobile assisted braking.