Abstract:  A 5 degree-of-freedom dynamic model was established for tractor and trailer lateral with yaw and roll motion for the rollover stability of heavy-duty semi-trailer trains under extreme conditions. A model predictive control method was used to obtain the yaw moments of tractor and trailer with an anti-rollover target controls. Two subsystems of active steering and direct yaw moment control were coordinated and controlled according to the vehicle real-time yaw rate and the tire load transfer rate. The joint simulation analysis was done by using TruckSim/Simulink pair for a layered hierarchical control strategy of semi-trailer. The results show that the maximum lateral accelerations are improved with the rates of 7.76% and 12.29% for the tractors and the trailers respectively under same conditions, the maximum absolutes of yaw angula-rate are improved with the rates of 23.88% and 3.39% respectively, and the maximum articulation angle of the car train is reduced by 19.87%. Therefore, the layered hierarchical control improves the anti-rollover stability of the vehicles due to active steering and direct yaw moment control compared with the traditional heavy-duty semi-trailer train.

Key words: automotive engineering, heavy-duty tractor-semitrailer, anti-rollover, multilevel hierarchical control, active front wheel steering, direct yaw moment control