Analysis and Stabilization of Chaos in the Electric-Vehicle Steering System

This paper presents a new control method to improve the safety performance of the electric-vehicle (EV) steering system. It is found that the EV steering system exhibits unstable chaotic behaviors at certain speeds, which can deteriorate the steering performance and even make vehicles fall into spin. In this paper, a new dynamic model is proposed to describe the EV steering system, which takes into account the motor drive for EV propulsion. Moreover, both the driver's reaction time and the disturbance caused by irregularities of the road surface are also incorporated into the EV steering model. It can be identified that periodic, quasi-periodic, and chaotic motions occur at the EV steering system with respect to different forward speeds. Thus, a new control scheme, namely the adaptive time-delayed feedback control (ATDFC), is proposed and implemented to stabilize the EV steering system from chaos to stable operation. Finally, the validity of the proposed model and control are verified.