High gain and sliding mode adaptive observers comparison: estimation of tire rolling resistance

This paper deals with the identification of suitable observation technique for estimation of the rolling resistance of a tire. Two nonlinear observers were applied in order to get a robust and accurate estimation of rolling resistance force. In this paper, a quarter car model is used and the adaptive high gain and the adaptive second order sliding mode (SOSML) techniques are compared. Their advantages and disadvantages have allowed choosing the most effective solution with respect to accuracy, robustness and computing complexity. The first simulation results of estimation of rolling resistance showed efficiency and precision of these two types of observers with a relative mean error less than 5 %. Their robustness to modelling error, parameter uncertainty and input noise was evaluated and used to detect the variation in the input. So, the convergence study has shown that the two observers ensure an asymptotic convergence toward zero error and that the adaptive high gain observer is faster than adaptive SOSML by 2 sec. Finally, simulation validation is carried out with software MATLAB/Simulink and SCANeR (TM) Studio (vehicle dynamic software). This brief paper presented the very first results of an original estimation of rolling resistance using adaptive gain observers.