Advanced motion control of electric vehicle based on lateral force observer with active steering

The motion stability of a vehicle depends on yaw-rate and side-slip angle. These two variables affect each other, and therefore, we performed decoupling control of yaw-rate and side-slip angle of an electric vehicle (EV) with active steering and torque difference between left and right in-wheel motors. However, the robustness of decoupling control is fragile for road condition. Hence, we propose lateral force observer (LFO) that is highly robust to variations in the cornering stiffness. LFO and yaw-moment observer (YMO) are used in an EV with an active steering and two in-wheel motors. In this paper, we compare the robustness of the proposed method and that of the decoupling-control method by means of an experiment. The results show that the proposed method delivers a better performance than the conventional method.