Modified Dynamic Model for Longitudinal Motion of Ground Vehicles

Abstract

The present study aims to provide a modified model for analysing the longitudinal dynamics of ground vehicles. Bearing in mind that an inevitable tire slip occurs under the transmission of driving torque to the drive wheels, the pure rolling assumption employed in many previous works is modified in this research. This paves the way through the development of a more realistic simulation framework with promising performance when used in vehicle and powertrain related topics. The modified equation of motion is an explicit function of tire slip ratio, and as a result, by rewriting the power balance equation, a dissipation term due to tire slip appears, which is consistent with the outcome of the recent contributions. Simulation results indicate a significant difference between the modified and simplified models in the case of a relatively high tractive force. Moreover, tire slip loss is obviously large in such a case, so that its neglect would lead to a noticeable inaccuracy in the response of the traditional model. An average of 35% improvement in the accuracy of prediction of tire consumed energy is observed in 0 to 100 km/h half-throttle acceleration manoeuvre using the modified model.