Control Schemes for Steer-by-Wire Systems

Torque and speed and two schemes for the control of an steer-by-wire (SbW) system. The former has the merit of a reaction torque that replicates the steering torque, including the torque existing between the steered wheels and the road surface. This implies that when the handwheel is rotated without turning the steered wheel and then released, the handwheel moves back toward the initial position in the same way as in conventional steering equipment. The latter scheme has the inconvenience that the steered wheels do not track the handwheel rotation accurately. The speed scheme instead is free from this inconvenience, however, it provides a reaction torque that does not replicate the steering one. This implies that the driver is not aware of the steering effort.