Robust yaw stability control for electric vehicles based on steering Angle-Disturbance Observer (SA-DOB) and tracking control design

A robust yaw stability control design based on active steering control is proposed for electric vehicles with in-wheel motors. The control system consists of an inner-loop controller (i.e., in this paper, called as a Steering Angle-Disturbance Observer (SA-DOB) which rejects an input steering disturbance and an output yaw disturbance simultaneously by feeding a compensation steering angle) and an outer-loop tracking controller (i.e., PI-type Tracking Controller) to achieve the nominal control performances. The model uncertainty including unmodeled high frequency dynamics and parameter variations occurs in the wide range of driving situations. Hence, a robust control design method is applied to controller design for guaranteeing robust stability and robust performance of the control system at the same time. The proposed control algorithm was implemented in CaSim model, which was designed to describe actual electric vehicles. The control performance of the proposed yaw stability control system is verified through computer simulations.