Experimental Study of Lateral Acceleration Feedback Control with Steer-by-Wire System

Steer-by-wire is a system that can independently control steering-wheel torque and vehicle-wheel steering angle. The object of this research was to realize a vehicle that can be driven according to driver's intention in any situation, such as in a crosswind, and rutted road surface. Using a steer-by-wire system, disturbance torque from the vehicle-wheels is not transmitted to the driver, signifying that the steering-wheel angle always indicates driver intention. Also, since unexpected feelings by active steering controls are reduced, feedback controls for the target vehicle behavior are easily realized. This research achieved good characteristics from steering-wheel angle to lateral acceleration by studying response characteristics using a vehicle equipped to measure lateral acceleration feedback. Moreover, the effects due to disturbance confirmed excellent results in two studies involving vehicle deviation during rut braking (vehicle-wheel input disturbance) and vehicle pull due to crosswind during high speed driving (body input disturbance). Furthermore, control-generated unexpected feelings could be reduced by controlling steering-wheel torque.