Method and apparatus for controlling an electric assist steering system

摘要

A steering assist system (10) providing assist in response to a steering control signal includes a vehicle speed sensor (150) for sensing vehicle speed and for providing a speed signal having a value indicative of the sensed vehicle speed and a torque sensor (110) operatively connected to a vehicle hand wheel (12) for providing a torque signal indicative of applied steering torque. A controller (120) is connected to the vehicle speed sensor (150) and to the torque sensor (110). The controller (120) includes a first set of torque-in vs. torque-out assist values (132) associated with a first vehicle speed and a second set of torque-in vs. torque-out assist values (130) associated with a second vehicle speed. The controller (120) provides the steering control signal in response to applied steering torque and having a value functionally related to (i) the vehicle speed signal and (ii) both the first set and second set of torque-in vs. torque-out assist values.