An optimal braking torque distribution control strategy for distributed drive electric vehicle under coasting regenerative conditions

Abstract

To address the concurrent optimization of vehicle stability, occupant comfort, and energy recovery efficiency during coasting regenerative braking for distributed drive electric vehicles, a three-layer optimization framework comprising estimation layer, optimization layer, and control layer is proposed. The estimation layer is responsible for estimating the road peak adhesion coefficient and the optimal tire slip ratio, while the optimization layer performs rolling optimization of the target speed during coasting regenerative braking. The control layer, based on a vehicle seven-degree-of-freedom model, uses Nonlinear Model Predictive Control algorithm to allocate braking torque distribution, aiming to balance vehicle stability, occupant comfort, and energy recovery efficiency. Co-simulation results based on Simulink and CarSim demonstrate that, compared with traditional methods in vehicle stability, the proposed algorithm improves braking economy efficiency by 2.5%, and enhances longitudinal and lateral comfort by up to 30% and 2%, respectively, under both high- and low-adhesion road conditions.