LQR active steering and LTVMPC yaw torque control for distributed drive electric tractor-semitrailer

To improve the trajectory tracking accuracy of intelligent vehicles under extreme working conditions, which are prone to side-slipping, instability, and other dangerous issues, new research on active steering and yaw moment control has been proposed. First, a three-degree-of-freedom (3-DOF) model of the tractor–semitrailer was established. The PID longitudinal driver model outputs the desired torque to achieve vehicle speed tracking, while the built-in driver in TruckSim serves as the lateral driver. Second, a lateral stability control strategy for the tractor–semitrailer was proposed. An LQR-based active rear-wheel steering controller for the tractor and a linear time-varying model predictive control (LTVMPC)-based direct yaw moment controller were designed to achieve active steering control of the tractor’s rear wheels and additional yaw moment control of the vehicle. The driving torque was further distributed between the tractor’s rear axles and the trailer using the quadratic programming method. Then, a TruckSim–MATLAB/Simulink co-simulation platform was developed to verify the designed controllers. Finally, the simulation results demonstrate that the combined LQR active steering and LTVMPC yaw moment control strategy offers significant advantages in reducing the side-slip angle and yaw rate of the vehicle during lane-change maneuvers, while effectively improving the lateral stability of articulated heavy vehicles.