Computer Model Prediction of the Directional Response and Stability of Driver-Vehicle Systems During Antiskid Braking.

Abstract

Findings specific to this work and applicable to moderate turning maneuvers during which full brake torque applications occur are: (1) passenger car antiskid systems operating under high friction conditions are effective in assisting drivers maintain directional and path control during full braking demand, only if, a) the rear axle is equipped with a select low ("worst wheel") axle control system, and/or, b) conservative prediction rules are employed in the antiskid logic, particularly at the rear axle location; and (2) under moderate friction conditions (most wet asphalt or concrete pavements), antiskid systems appear to have greater effectiveness in assisting drivers maintain directional and path control of vehicles during limit braking maneuvers. Since the principal mechanism responsible for severe alteration of the directional dynamics of the vehicle during hard braking is the fore/aft load transfer, the level of deceleration and the ability of drivers to adapt quickly to an altered dynamical system, together determine the level of closed-loop braking performance that can be achieved.