Abstract
Rollover of heavy tractor/semi-trailer trucks Is a serious concem by its human and financial consequences. The paper describes an approach to estimate the roll state of a combination tractor/semi.trailer vehicle. The main feature of this approach is that the detection is performed only by measurements done on the towing vehicle exclusively which implies numerous practical advantages. Simulations performed on data for real vehicles show that detecting the lift-off threshold of the semi-trailer's rearmost inner wheel as the first stage of the rollover process might be feasible based on data collected on the tractor only. The remote target of these researches is to educate the driver by giving him/her a better knowledge of the rollover propensity of his/her vehicle.