Vehicle online parameter estimation using a nonlinear adaptive observer

This paper presents a nonlinear adaptive observer for the estimation of the wheel stiffness and radius. The estimated parameters will be used for controller synthesis and supervision for vehicle applications. The proposed adaptive observer uses the angular velocity as an input of the system, whereas the angular position and the vehicle velocity are considered as a measured state vector. The adaptive observer is designed based on a nonlinear model of the vehicle quarter model and the adaptive law of the parameters is derived using Lyapunov analysis. Simulation results show clearly the effectiveness of the proposed observer that achieved a good performance for vehicle parameter estimation.