A semiphysical tyre model for vehicle dynamics analysis of handling and braking

Abstract

A semiphysical model presented in this paper first includes the transient steer effect characterized by both the time delay of steering application and the stress relaxation of friction due to the tyre’s viscoelastic property. The model experimentally formulates the vertical force as a function of the tyre deflection, camber angle and lateral force. In order to describe the longitudinal and lateral forces as functions of the tyre’s characteristic parameters such as stiffness and friction, the basic formulations of the UA tyre model are reused. For self-aligning and overturning moments, first the application points of three forces are experimentally formulated, and then the moments are expressed as functions of the three forces and their application points. All characteristic parameters are experimentally determined as functions of the load, camber angle, slip angle, slip angle sweep rate and/or slip ratio for cornering and/or driving–braking. For the purpose of validation, the model is implemented into ADAMS and then its simulation results are compared with measurement data for various test conditions.

Keywords:

• Tyre model
• Tyre’s characteristic parameters
• Transient steer
• Time delay
• Stress relaxation
• Loaded radius
• Vertical stiffness