Nonlinear active rollover prevention control strategies for a 5-axle tractor/semitrailer

This paper presents new active control strategies to prevent heavy vehicle rollover and focuses mainly on cases of maneuver-induced rollover such as rollover in cornering and lane-change maneuvers. Two performance measures as control strategies are explored: the lateral load transfer ratio and the trailer lateral acceleration. A nonlinear 75,000 pound 5-axle tractor/semitrailer computer simulation model has been used to demonstrate the effectiveness of the proposed active control system. A new non-linear sliding mode controller has been designed and found to be effective in improving the dynamic performance and roll stability, regardless of parameter uncertainties, such as tires or suspension characteristics. The controller torque requirement is limited by the differential dynamic braking forces that the tractor drive axles are able to produce as a function of the applied dynamic loads and road surface condition. The results show that with this new controller, the vehicle lateral acceleration can be controlled to prevent rollover without significant change of the vehicle trajectory when active yaw torque is applied to the tractor drive axles. Also, simulation results indicate that the vehicle rollover might be prevented using either the lateral load transfer ratio or the lateral acceleration at the trailer centre of gravity as control strategies.