Integrated estimation structure for the tire friction forces in ground vehicles

This paper presents a novel corner-based force estimation method to monitor tire capacities required for the traction and stability control systems. This is entailed for more advanced vehicle stability systems in harsh maneuvers. A novel estimation structure is proposed in this paper for the longitudinal, lateral, and vertical tire forces robust to the road friction condition. A nonlinear and a Kalman observer is utilized for estimation of the longitudinal and lateral friction forces. The stability and performance of the time-varying estimators are explored and it is shown that the developed integrated structure is robust to model uncertainties and does not require knowledge of the road friction. The proposed method is experimentally tested in several maneuvers on different road surface conditions and the results illustrate the accuracy and robustness of the state estimators.