Lateral Tire Force Estimation With Unknown Input Observer

This paper presents the development of a lateral tire force estimation algorithm. Rather than using highly nonlinear tire-road friction models, the unknown input observer combined with the yaw rate measurement is proposed to estimate the yaw moment generated by the lateral tire forces with respect to those selected reference points. Two types of unknown input observers are designed for this purpose in the study. Finally, the estimation of the sum of the lateral tire forces of two front wheels and two rear wheels are obtained from these estimated yaw moment signals through a simplified kinematic model.