Effect of driver response on vehicle stability

This research explores how drivers affects the vehicle stability. Three representative maneuvers were considered for the stability analysis: straight-line driving, constant radius cornering, and lane-change. Any generic maneuver can be represented by a composition of these three maneuvers. The model used to describe vehicle motion is a five-degree-of-freedom bicycle model incorporating vehicle longitudinal and tire dynamics. A single-point preview-based driver model was employed to examine driver behavior. A parametric study is conducted using table-top driving simulator to identify the driver parameters. A bifurcation study was performed to study the vehicle stability, and the shift in bifurcation points due to lateral load transfer was also captured. Next, the interaction between vehicle and driver is examined through global characteristics, employing eigenvalue and dissipation energy methods. The findings show that front wheel driven vehicles are more stable than rear wheel driven ones in straight-line motion, with stability improving as more torque is directed to the front wheels. It was observed that with driver intervention even front wheel driven vehicles can become unstable at higher torque thresholds. In the case of cornering, a skewed all wheel drive setup is preferred. The study also discusses how varying steering responses can stabilize or destabilize cornering. The lane change maneuvers were analyzed for constant driving speeds and the stability trends mirrored those of the straight-line and cornering.