Coupled dynamics of electric vehicle with a novel solution of equilibrium under regenerative braking

In this paper, to focus on the vehicle handling stability under regenerative braking, a nonlinear high-dimensional vehicle dynamics model considering longitudinal and lateral coupling and load transfer was established. By conducting the experiments to obtain the regenerative braking torque characteristics, fitting expressions are introduced into the dynamics model of the vehicle to analyze the coupled dynamic behavior and stability variations under different maneuvers during regenerative braking. A genetic algorithm-based method is proposed to solve stable stem of the high-dimensional vehicle systems. The results indicate that the vehicle loses stability under both conditions, once unstable the vehicle has difficulty restoring stability under braking force. For stable region of initial states, the phase trajectory rapidly converges to a stable stem. The length of stable stems could serve as a reference indicator for single-pedal regenerative braking controller design. Meanwhile, the initial conditions should close to the stable stems, ensuring that the vehicle can quickly restore stability under perturbation, to improving the robustness of vehicle handling under braking conditions.