A study of the cornering force by use of the analytical tyre model

Abstract

An analytical tyre model for the cornering force (CF) and the self-aligning torque (SAT) is described on the basis of the Fiala model. The CF and SAT come mainly from the shear stress and sliding friction at the tread–road interface. The variations in CF and SAT also change the kinetic conditions for their own generation, mechanisms; that is, the contact pressure distribution, the tread-base shape and the relative position of the steering axis within the contact patch are altered. The present model, namely the CF–SAT system model, which includes the conditional changes through the CF and SAT feedback loops, approximates the slip-angle dependence of CF and SAT with high accuracy. Least-squares fit of the measured data with the combined use of the cornering power–self-aligning torque power system model and the CF–SAT system model reveals the equivalent part stiffness, the tread friction coefficient and the transient circumferential distribution of contact pressure. The system models may be useful for both tyre production at tyre makers and the vehicle dynamics simulation at car makers.

Keywords:

• Tyre model
• Cornering force
• Self-aligning torque
• Tyre part stiffness
• Friction
• Cornering force–self-aligning torque system model