This paper presents an elegant frequency domain approach that can be used to analyze lateral vehicle dynamics for transient understeer and oversteer performance. Commonly used steady-state understeer analysis techniques are not able to expose some effects, such as tire relaxation, in on-center transient maneuvers. The approach presented here addresses such transient issues using a simple two degree of freedom handling model coupled to a model for tire lateral dynamics. In addition to the usual yaw rate and lateral acceleration transfer functions, this paper proposes using an understeer angle transfer function as an easy-to-interpret metric to evaluate transient on-center handling. Using the approach, it is shown that at low vehicle velocities, the inclusion of tire relaxation introduces dramatically different system dynamics by introducing highly undamped poles into the coupled system for both an understeering and an oversteering vehicle.

This content is only available via PDF.
You do not currently have access to this content.