SYSTEM AND METHOD FOR PROVIDING STEERING TORQUE ASSISTANCE TO AN ELECTRICALLY-POWERED STEERING APPARATUS OF A VEHICLE

A system for providing steering torque assistance to an electrically-powered steering apparatus comprises a torque assistance motor coupled to the steering apparatus. A steering controller is configured to cause the torque assistance motor to apply a commanded level of steering torque assistance to the steering apparatus. The steering controller is configured to determine the commanded level of steering torque assistance based on a product of a scheduled level of steering torque assistance and a torque assistance scale factor, wherein the scheduled level of steering torque assistance is determined from a scheduled torque assistance characteristic having a nominal assist. The steering controller is configured to determine a scaled assist based on feedback from one or more safety sensors; and the torque assistance scale factor is determined as a ratio of the scaled assist and the nominal assist.