ELECTROMECHANICAL POWER STEERING SYSTEM CONTROL USING ONLY MEASURED OR ESTIMATED STEERING TORQUE SIGNAL

摘要

The invention relates to a method for control of an electric motor (2) for an electromechanical power steering mechanism (1) for assisting steering for a motor vehicle, the electromechanical power steering mechanism (1) comprising a steering column (5) with an upper steering shaft (4) linked to a lower steering shaft (6) by a torsion bar, wherein the torsion angle (10) between the upper steering shaft (4) and the lower steering shaft (6) is measured or estimated and an electric motor (2) being adapted to apply an assistance torque, wherein the method includes the following steps: Calculation of a desired rotor position (12) by an assist algorithm (11) based on the torsion angle (10); and Calculation of a PWM pattern (13') by a PWM control unit (13), in such a way that the calculated PWM pattern (13') adjusts the rotor of an electric motor angle (14) such that the torsion angle (10) is decreased.