Abstract
The purpose of the activity is to produce an innovative control strategy for a steer by wire system. 'X' by wire systems are characterized by a separation between the driver's command and the effect on the vehicle. The intermediate is a CPU interpreting the driver desires in the best possible way.
The purpose in the control logic elaboration was to obtain a constant yaw rate gain, a compensation of lateral wind phenomena both in straight ahead and in turn travel, and the integration with other active chassis control systems like Vehicle Dynamics Control. Nowadays Electric Power Steering (EPS) systems carry out a servo-assistance devoted to apply to steering rack the necessary auxiliary torque to determine the reference trajectory. An EPS needs a rotation of steering wheel depending both on trajectory radius and vehicle speed. An EPS acts on the steering rack without the possibility to independently impose the wheels sideslip angle. A steer by wire system can make steering wheel rotation depending only on trajectory radius. Moreover, a steer by wire can impose separately the wheel sideslip angle. Such capability permits to maintain both in stationary and in transient maneuvers a desired relationship between sideslip angles, for example the one due to Ackerman's law. The paper presents the activity managed to carry out a steer by wire control strategy devoted to increase vehicle handling and safety during stationary and transient manoeuvres.