Method and system for safe limiting of torque overlay intervention in a power assisted steering system of a road vehicle

Abstract

Disclosed herein is a method and arrangement for safe limiting of torque overlay intervention in a power assisted steering system of a road vehicle having an autonomous steering function arranged to selectively apply a steering wheel overlay torque to a normal steering assistance torque. A wheel self-aligning torque (ƒR) of the road vehicle is modelled for a current vehicle velocity (ν) and pinion angle (δw). A steering wheel overlay torque request (τR) is received. Based on the received steering wheel overlay torque request (τR) is provided a steering wheel overlay torque (τA) in hands-off applications limited to a safe set interval that is symmetrical around the modeled wheel self-aligning torque (ƒR).

Dependencies are inferred from the claim text.