Method and apparatus for controlling an electric assist steering system using an adaptive torque filter

摘要

A steering assist system (10) providing assist in response to a steering control signal includes a vehicle speed sensor (56) for sensing vehicle speed and for providing a speed signal having a value indicative of the sensed vehicle speed and a torque sensor (44) operatively connected to a vehicle hand wheel (12) for providing a torque signal indicative of applied steering torque. A controller is connected to the vehicle speed sensor (56) and to the torque sensor (44). The controller includes an adaptive torque filter (80) that maintains a selectable system bandwidth independent of gain changes and vehicle speed changes. The adaptive filter (80) recovers any gain reduction by increasing the frequency of a filter pole.