Roll Stability Control for Torsionally Compliant Vehicles

Rollover prevention is now part of complete vehicle stability control systems for many vehicles. Given that rollover is predominantly associated with vehicles with high centers of gravity, the targeted vehicles for rollover protection include medium and heavy duty commercial vehicles. Unfortunately, the chassis designs of these vehicles are often so compliant in torsion that the ends of the vehicles may have significantly different roll responses at any given time. The potential need to assess and correct for the roll behavior of the front and rear ends of the vehicle is the subject of this paper.

Most rollover mitigation research to date has used rigid chassis assumptions in modeling the vehicle. This paper deals with the roll control of vehicles with torsionally flexible chassis based on a yaw-correction system. A simplified model of a single-unit vehicle with chassis torsional compliance and an integrated roll controller is exercised using step, ramp and swept sine steering inputs to select the gains for a state feedback controller. Simulation results show that, for the vehicle considered, the performance of a locally selected controller that adds roll stability is more sensitive to payload than torsional compliance. Also, a set of controller gains selected as satisfactory for a soft or stiff chassis could give poor performance or even destabilize the vehicle when the torsional stiffness changes.