Design of steer-by-wire system with bilateral control method using disturbance observer

Steer-by-wire system, in which the conventional mechanical linkages between the steering wheel and the front wheel are removed, is suited to active steering control, improving vehicle stability, dynamics and maneuverability, as well as to autonomous steering control to assist the driver. Conventional controller for SBW system is designed by general feedback control method. However, driver can not exactly feel reaction torque generated from tire. In this paper, the goals are considered as following two points. One is a reproduction of environmental impedance in steering wheel. The other is improved maneuverability for SBW system. Moreover, control stability must be satisfied. Using disturbance observer, bilateral controller is designed. Through analysis, it is confirmed that the three desired conditions in SBW system are well satisfied with this controller. The effectiveness of this research is demonstrated by experiment.