Tire model for simulations of vehicle motion on high and low friction road surfaces

Abstract

An on-road analytical tire model has been developed to predict tire forces and moments at the tire/road interface. The model is computationally efficient and it only requires a limited set of easily obtained input parameters. Force and moment calculations are based on mechanical analogs that describe longitudinal and lateral tire tread and sidewall deflections during braking, traction and cornering. Longitudinal deflections are determined using a simple linear elastic spring model, while lateral deflections are calculated using an elastic beam model. Surface sliding friction is defined by experimental curves relating the friction coefficient to the wheel/road differential velocity. Source code has been developed to include the model as a force element subroutine in commercially available dynamic analysis software known as DADS (Dynamic Analysis Design System). The tire model has been successfully demonstrated in DADS using a simple simulation of a tire test device. Preliminary comparisons of model predictions with available test data have been favorable. Efforts are underway to incorporate the tire subroutine into a DADS model of a HMMWV to conduct driving simulations on dry, snow and ice covered road surfaces.