Adaptive Anti-slip Regulation Method for Electric Vehicle with In-wheel Motors Considering the Road Slope

Anti-slip regulation (ASR) is one of the research focus in the field of active safety of electric vehicle. An ASR algorithm adaptive to road condition is proposed in this paper based on 4WD electric vehicle with in-wheel motors. The controller based on anti-windup sliding mode control is robust to wheel parameter uncertainty. The longitudinal velocity estimator based on the fusion of dynamics method and kinematics method is adopted to reduce the velocity estimation error. The road slope is estimated using recursive least square with forgetting factor and the longitudinal acceleration sensor information is calibrated by the road slope estimation for slope adaptive velocity estimation. At the same time, a road coefficient estimator is adopted to estimate road condition using improved Burckhardt model, so the optimal reference slip ratio is selected according to the estimated road adhesion coefficient for the maximum driving efficiency and the realization of adaptive anti-slip regulation. Multi-condition simulations show that the controller is adaptive to road changes, and it can suppress wheel slip ratio and ensure the vehicle stability.