ABSTRACT
A nonlinear four-wheel vehicle and tyre model including a versatile drive train model is applied to study the impact of different drive concepts on the handling diagram at both conventional and extreme handling manoeuvres. Stability and mode shapes are examined by inspecting eigenvalues and eigenvectors of the locally linearised system, and joint modal controllability and observability is investigated by means of a respective measure. It turns out that at the limits of handling, e.g., the presence of steady-state powerslide not only depends on drive torque distribution between the rear and front axle, but also on the (terminal) over-/understeer handling characteristics at regular driving. Evaluating joint modal controllability and observability indicates that the effectiveness of redundant inputs, such as steering wheel angle and drive torque, to control the (unstable) steady-state condition, depends on drive torque distribution and handling characteristics as well. These findings have been confirmed by adapting a driver model capable to handle powerslide manoeuvres while tracking the demanded (circular) trajectory.
