Vehicle motion control method using yaw-moment observer and lateral force observer for electric vehicle

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 differencebetween 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 ofan experiment. The results show that the proposed method delivers a better performance than that of the conventional method. © 2010 The Institute of Electrical Engineers of Japan.