An Analysis of Tire Traction Properties and Their Influence on Vehicle Dynamic Performance

An analysis is made of the influence of tire-mechanics characteristics on the behavior of an automobile undergoing maneuvers requiring the tires to produce combined longitudinal and lateral forces. The mathematical model employed to represent the vehicle incorporates wheel rotational degrees of freedom and relationships expressing the longitudinal and lateral tire shear force components as analytical functions of tire normal load, sideslip and inclination angles, and longitudinal slip.

The tire shear force relationships, derived by extrapolating from existing theory for the traction mechanics of a freely rolling tire, agree qualitatively with available experimental data. Analog simulation results are examined to assess the influence on vehicle steering/braking response of variations of three parameters: lateral tire stiffness, longitudinal tire stiffness, and the coefficient of friction at the tire/road interface.