Non-linear tyre forces estimation based on vehicle dynamics observation in a finite time

Abstract

This paper presents a new method for estimating tyre forces. The tyre-road contact set in play the dynamics of the vehicle. Through the reconstruction of the vehicle dynamics, the tyre forces can be estimated. The approach used here to reconstruct the vehicle dynamics and to estimate the tyre forces is based on the techniques of sliding-mode observers. The structure of the observer is developed on the basis of a four-wheeled vehicle model. The latter is a rigid-body model with 14 degrees of freedom. Then a vehicle dynamics state is defined with the tyre forces considered as variables with unknown dynamics. A step-by-step algorithm based on the sliding-mode observer is designed in order to reconstruct the vehicle dynamics in finite time and gives the estimation of the tyre forces. To examine the validity of the proposed approach, field-test data are used.