Genesis of booster curves in Electric Power Assistance Steering systems

The typical architecture of an Electric Power Assistance Steering (EPAS) system includes a static map to provide the correct amplification to the driver´s exerted torque. In literature, it is generally known as booster curve. This paper concerns the study of the amplification criteria, that are commonly used to these booster curves. The basic concepts of the Electric Power Steering (EPS) systems with a realistic model for the friction contact, that acts on the wheels are discussed. A relation between the assistance and the driver´s torque is provided, under the hypothesis of a position-oriented control of the movement and the Stevens´ power law. Finally, the simulation results proposed at the end of this paper validate the shape of the booster curves and are in accord with the initial hypothesis.