Abstract: The present invention relates to an electromechanical motor vehicle power steering mechanism for assisting steering of a motor vehicle by conferring torque generated by an electric motor to a steering mechanism. A steering controller receives at least signals representative of the vehicle velocity and the torque applied to a steering wheel and a rotor position signal to determine a target motor torque, a motor controller which receives the target motor torque from the steering controller and transfers it into target voltages expressed in a coordinate system fixed to the stator and a motor driver which transforms the target voltages into motor currents, at least one current measurement unit which measures the motor currents, wherein the mechanism further comprises a current estimation unit which estimates the target currents and a diagnostic unit which compares the estimated target currents to the measured motor currents in order to identify and remedy occurring faults.

Abstract: The present invention relates to an electromechanical motor vehicle power steering mechanism for assisting steering of a motor vehicle by conferring torque generated by an electric motor to a steering mechanism. A steering controller receives at least signals representative of the vehicle velocity and the torque applied to a steering wheel and a rotor position signal to determine a target motor torque, a motor controller which receives the target motor torque from the steering controller and transfers it into target voltages expressed in a coordinate system fixed to the stator and a motor driver which transforms the target voltages into motor currents, at least one current measurement unit which measures the motor currents, wherein the mechanism further comprises a current estimation unit which estimates the target currents and a diagnostic unit which compares the estimated target currents to the measured motor currents in order to identify and remedy occurring faults.