Estimation of road adhesion coefficient for four-wheel independent drive electric vehicle

In order to improve the stability of the vehicle during control process, it is necessary to estimate vehicle state parameters. One of the most important parameters is the road adhesion coefficient. In this paper, Dugoff tire model, seven-degree-of-freedom (7-DOF) vehicle model and adhesion coefficient observer based on unscented Kalman filter (UKF) algorithm are established by taking the four-wheel independent drive electric vehicle (4WID) as the research object. Through the joint simulation of Simulink and CarSim, this paper carries out simulation verification under three different conditions: high attached road, low attached road and joint road, and compares the estimated value with the set value in CarSim. The results show that the road adhesion coefficient estimated by proposed method can track the set value accurately and satisfy requirements of vehicle dynamics control.