Global coordinated control framework for advanced all-wheel steering and driving vehicles: Unleashing potential through tire slip state assessment

To address the challenge of efficient actuator coordination in all-wheel steering and driving vehicles, this paper proposes a global coordinated control framework based on tire slip state assessment. First, a hybrid feedforward control method comprising steady-state control, dynamic compensation, and oblique steering compensation is proposed to respond rapidly to the driver's demands under various driving conditions. Then, considering different steering modes of four-wheel steering vehicles, a driver intention interpretation method that integrates conventional steering and oblique steering is developed. Subsequently, a sliding mode control algorithm is utilized to track the driver's desired motion states, improving the vehicle's robustness against system disturbances. Moreover, taking lateral acceleration and yaw rate as inputs, a coordinated strategy for the four-wheel steering angles and driving torques is established based on tire slip state assessment. Finally, hardware-in-the-loop test results show that, compared to the model predictive control (MPC) algorithm, the proposed control scheme increases the maximum speed in double lane-change maneuvers by 13%, significantly improving the vehicle handling performance under different driving conditions.