Influence of Front/Rear Drive Force Distribution on the Lateral Grip and Understeer of All-Wheel Drive Vehicles
The increased control potential in all-wheel drive vehicles enables the vehicle to maintain understeer characteristics from the linear tire range up to the grip limit. This provides consistent feedback to the driver over a wider range of operating conditions than for two-wheel drive vehicles. In order to aid the development of current and emerging driveline systems, the authors see a need for improved theory and methods (numerical and graphical) describing the influence of drive force distribution on these said factors. In this work the methods for computing the lateral grip margin for a general drive force distribution are developed for four special cases; front-wheel drive, rear-wheel drive, rigid all-wheel drive; and finally, an optimal front/rear drive force distribution.