The Modeling of Tire Cornering Characteristics Considering the Transient Vertical Load Change

Abstract

The tire cornering behavior running on uneven roads, which induces the tire vertical load change, is presented in this paper. At first, the side force and aligning moment responses under time-varying vertical load at a given slip angle were measured to investigate the wave form change due to the wavelength change of vertical load. Then, the tire model was developed, where the small slip angle was assumed. The calculated results showed good agreement with experiments in the range of wavelengths not less than about two meters. Next, the model was improved so as to cover the wide range of slip angle. For the improvement, the functional expression of the so-called relaxation lengths depending on the vertical load and the equivalent slip angle was newly proposed. It was concluded that the improved model predictions agreed well with the experimental results in a wide range of slip angle. The calculated side force response seemed to agree with measurements even in the range of wavelengths less than two meters.