Abstract
Keywords - superposition steering, variable steering ratio, all-wheel-drive, torque vectoring, active safety
The steering system, as the most important interface between the driver and the vehicle, significantly affects driving pleasure, driving comfort and driving safety. To optimize these attributes, the steering effort has to be freely adjustable for all driving situations for steering angle demand (operation angle) and steering torque demand (operation force). The Audi dynamic steering for the first time allows both degrees of freedom. As new functionalities compared to the well known Servotronic the functionalities variable steering ratio and various functions for active vehicle stabilization were possible and have been realized in the new Audi A4, A5 and Q5. A perfect partner for the dynamic steering system is the active sport differential. This innovative all-wheel-drive system distributes torque from the engine in continuously variable proportions between the rear wheels. This greatly enhances agility, driving pleasure and active driving safety. The controlled power flow enables the car to take corners even more directly and responsively, and to retain its directional stability considerably longer.