ABSTRACT
In order to improve the active safety for vehicle, nonlinear real-time observer for estimation of longitudinal velocity with road maximum friction coefficient for four-wheel-independent-drive EVs was proposed. Vehicle longitudinal velocity was estimated using the feedback value of each wheel slip ratio and longitudinal acceleration sensor, and the convergence of estimation error is proved. In order to improve accuracy for calculating slip ratio under different road conditions, the road maximum friction coefficient(RMFC) estimator was proposed based on modified Burckhardt tire model. The amount of computations for this method is small but with high estimation precision. The effectiveness of the algorithm and adaptive law was validated through experiments in various working condition.
