Observability matrix and parameter identification: application to vehicle tire cornering stiffness

Tire cornering stiffness is an important parameter of vehicle modeling. Together with sideslip angle it is a transversal force governing tire-road contact, and like sideslip angle it can be used to evaluate lateral vehicle stability. This paper presents a vehicle sideslip angle observer based on a nonlinear vehicle model. This observer is validated with experimental data. Using the properties of the observability matrix, the paper shows that tire cornering stiffness is identifiable from the singular values of this matrix. An identification procedure is performed, by simulation, with double lane-change tests. Th results of this identification are validated on a slalom test. The study is carried out using a realistic vehicle simulator.