Abstract: Roll-over crash tends to occur in the heavy tractor semi-trailer, therefore improving the vehicle is roll stability can reduce the occurrence of accidents and the losses of lives and property. The 8 DOF heavy tractor semi-trailer dynamic model is built with adjustable speed, based on LQG/LTR for the vehicle roll stability control. The full-state feedback controller is also established and the part LQG/LTR feedback controller can realize the best control in various speed situations, and the active roll control can work in spite of noise interference. The vehicle under the condition of variable speed step steering is simulated, and the parameters such as standard lateral load transfer are compared and analyzed. The simulation results of the vehicle show that the LQG/LTR works well in spite of noise interference, and can improve the robustness and stability of system. Comparing with passive vehicle, the full-state gain control method can effectively improve the roll stability of heavy tractor semi-trailer.

Key words: Active roll control, Global gain scheduling, Heavy tractor semi-trailer, Roll stability