Distributed drive 4WS intelligent driving vehicle trajectory tracking and lateral stability control

To improve the accuracy of trajectory tracking and lateral stability of autonomous vehicles in intelligent driving, a distributed drive four-wheel steering (4WS) trajectory tracking and lateral stability control algorithm with a hierarchical architecture is proposed. Firstly, an upper-level 4WS trajectory tracking controller with feed-forward control is designed based on a linear quadratic regulator (LQR) to determine the front and rear wheel steering angles. A PID-based longitudinal driver model is designed to output the required total driving force for vehicle speed tracking. Secondly, a lower-level linear time-varying model predictive control (LTVMPC) direct yaw moment controller is developed based on a two-degree-of-freedom single-track vehicle model. The optimal additional yaw moment is computed by iteratively solving a constrained optimisation problem, and it is distributed using the axle load ratio method. Finally, a co-simulation platform based on CarSim and MATLAB/Simulink is employed to simulate and analyse the controller's performance. The results show that the 4WS+LQR+LTVMPC strategy effectively reduces the lateral offset, heading angle offset, and sideslip angle while improving the trajectory tracking accuracy and lateral stability of the vehicle.