AUSGLEICH PERIODISCHER SENSORFEHLER BEI ELEKTRISCHEN SERVOLENKUNGSSYSTEMEN

An electric power steering system includes a steering wheel (76), an electric assist motor (94) operatively coupled to the steering wheel (76), and an electronic controller (92) operatively coupled to the assist motor (94). A steering wheel position sensor (102) provides an output indicative of an angular position of the steering wheel (76). A motor position sensor (95) provides an output indicative of a relative angular position for the motor (94). Steering wheel position sensor output (52) is acquired at each of a plurality of angular positions of the motor (94), thereby establishing a set of points (50) defining a curvilinear relationship between steering wheel sensor output (52) and motor position sensor output. The set of points (50) is sampled to calculate a straight line which approximates the curvilinear relationship, thereby reducing periodic errors in the steering wheel sensor output (52). The straight line is employed to determine a position offset for the motor position sensor output corresponding to a system zero position. The system zero position is a position for which the vehicle will travel along a linear, substantially straight-ahead path.