Cooperative Trajectory Tracking and Stability Control with Improved Stability Criterion for Intelligent Four-Wheel-Independent-Drive Electric Vehicles

Accurate trajectory tracking control with guaranteed vehicle dynamics stability is fundamental for automated vehicles. This paper proposes an enabling trajectory tracking scheme with improved dynamics stability for four-wheel-independent-drive electric vehicles. First, a modified phase plane method is proposed for assessing vehicle dynamics stability by constructing a 3-D phase trajectory. Then a lateral trajectory tracking controller is developed using a model predictive control algorithm with a variable stiffness tire model. Considering the effect of the additional yaw moment on the trajectory tracking error and vehicle yaw stability, a dual-weight cooperative sliding mode control method is established for yaw angle tracking compensation and yaw stability control through target switching. Finally, the desired additional yaw moment and total longitudinal tire force are achieved through wheel torque allocation while accounting for the slip ratios. The performance of the proposed method is evaluated through comprehensive Hardware-in-the-Loop tests under double-lane change maneuvers.