Tire Forces and Moments and On-road Lateral Stability of Articulated Steer Vehicles

The on-road lateral stability of an articulated steer vehicle is investigated for both small and high deviations. First, for small deviations, a linear model of the vehicle is devised and analyzed. This planar model is generated based on some simplifying assumptions. For instance, the equations describing the tire forces and moments are linearized, and the tire rolling resistance is neglected. A linear stability analysis of the straight line motion of the vehicle with constant forward speed is conducted by using this simplified model for different values of the torsional stiffness and damping at the articulation joint. To investigate the lateral stability of the vehicle at higher deviations, the motion of a virtual prototype of the vehicle in ADAMS/View is simulated for different conditions. Finally, the results from the simulations and the linear stability analyses are compared. These comparisons show that the tire rolling resistance can change effectively the results predicted by the linear analysis. In addition, at higher deviations, the effects of the nonlinearity of the tire aligning moment behavior appear and thus, the dynamic behavior is significantly different from that predicted by the linear analysis.