Improvement of steady-state PAC2002 under the sideslip and turn slip inputs based on the discrete theoretical tire model

Abstract

Semi-empirical tire model considering turn slip input is of great significance for the force feedback of vehicle at low speed or small turning radius conditions. In this paper a refined discrete model considering contact patch and the deformation of the belt/carcass which are from the finite element model is established. New force and moment calculation matrix equations are constructed and different iterative methods are compared and Richardson iteration has been chosen because of its best iteration speed. The tire dynamics characteristics under sideslip and turn slip inputs are analyzed based on the discrete model simulation results. It shows the PAC2002 influence coefficients of turn slip on peak value of side force and cornering stiffness can not be well expressed under different loads. And at small loads, the peak value and stiffness of aligning moment relative to turn slip under different sideslip angles can not well be expressed. According to above problems, the PAC2002 model is improved. After improvement, the average error of lateral force relative to sideslip angle under different turn slip is reduced from 3.7% to 1.4%, the average error of lateral force relative to turn slip under different sideslip angle is reduced from 9.9% to 3.6%. And the error of aligning moment relative to sideslip angle under different turn slip is reduced from 8.5% to 5.1% and the error of aligning moment relative to turn slip under different sideslip angle is reduced from 8.9% to 3.2% at small loads. The improvement proposed in this paper have a good result.