Experimental study for free rolling of tire on ice

Considering that tires play a vital role not only in the performance but also in the safety of a vehicle, studying the tire-road interaction has always been a matter of interest, specifically when the tire is travelling on icy roads. However, most of the existing studies focused on tire performance on ice for traction or braking conditions [1,2] and not many studies have been devoted to the free rolling of a tire. Considering the tire in its free rolling condition is a necessary step in assessing the friction force at the tire-ice interface, which can be used next to predict the torque to be applied on the tire in order to create a zero slip condition in the tire-ice contact patch. The zero slip condition is always difficult to obtain, as it needs a very accurate assessment of the effective rolling radius of the tire. This study is a part of a more comprehensive study to investigate the effects of different tire parameters, such as rubber compounds properties on tire performance on ice. For the work presented in this paper the main objective is benchmarking the results from existing methods for obtaining the effective rolling radius of the tire and the equivalent dynamic friction coefficient of the tire on ice. The investigation approach was to experimentally study a tire under free rolling on ice. A set of experiments were thus designed and conducted for the Standard Reference Test Tire (SRTT) on a layer of ice in the Terramechanics Rig in the Terramechanics, Multibody and Vehicle Systems laboratory (TMVS) Laboratory at Virginia Tech under different applied normal load and various inflation pressure conditions. The data collected from the tests performed was used to obtain and compare the result for effective rolling radius of the tire and equivalent friction coefficient. The data collected on the Terramechanics Rig by the 6-axis wheel load measurement system P650 by Kistler was processed to eliminate the noise of the raw data using zero phase filtering techniques in MATLAB. Other parameters measured during the tests conducted were the tire loaded radius, the width of contact patch, and the temperature distribution in the tire-ice contact patch.