Nonlinear tyre model-based sliding mode observer for vehicle state estimation

A nonlinear sliding mode observer is proposed to estimate the lateral and longitudinal velocities and yaw rate of an automotive vehicle. The observer is based on standard outputs available in nowadays cars such as longitudinal and lateral accelerations, yaw rate, wheel rotational speed and steering angle. Tyre friction forces are described using the nonlinear Magic formula model, and the stability analysis is performed based on a Lyapunov quadratic function and the Sylvester criterion. The accuracy and the robustness of the observer are assessed by means of numerical simulation assuming very challenging driving scenarios and parameters uncertainties.