Improvement Maneuverability and Stability of Independent 4WD EV by DYC Based on Control Target Dynamic Regulation

Abstract

A direct yaw-moment control (DYC) method based on the dynamic regulation of the control target is proposed to achieve integrated optimization between maneuverability and stability for the independent 4WD EV. Firstly, the yaw rate responses are calculated from the modified bicycle model, which respectively represent the maneuverability and stability of EV. With these responses deduced, the integrated control target for the maneuverability and stability is determined for all steering situations. Furthermore based on the “feedforward+feedback” control structure, the DYC controller is designed which combines the dynamical sliding mode control (DSMC) and LQ control. DSMC avoids the drawbacks of the oscillations by chattering happening in the classical SMC and allows the smoothness of the direct yaw-moment. The simulation experiments show that this DYC system can restrain the side slip angle effectively and keep higher yaw rate, which guarantees the EV maneuverability and stability. Moreover, the robustness of systems for road adhesion conditions variation and vehicle parameters uncertainties is also guaranteed in simulation validation.