LIMP ASIDE STEERING ASSIST WITH ESTIMATED MOTOR CURRENT

摘要

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.

主权项

1. 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, the mechanism comprising:
a steering controller which receives signals representative of at least the vehicle velocity (v) and the torque (TTS) applied to a steering wheel and a rotor position signal to determine a target motor torque (Td), a motor controller which receives the target motor torque (Td) from the steering controller and transfers it into target voltages (Uα,d, Uβ,d) expressed in a coordinate system fixed to the stator; a motor driver which transforms the target voltages (Uα,d, Uβ,d) into motor currents (IU,IV,IW); at least one current measurement unit which measures the motor currents (IU,IV,IW); and a current estimation unit which estimates the target currents (Idest,Iqest=I1, est) and a diagnostic unit which compares the estimated target currents (Idest,Iqest=I1, est) to measured currents (Iq1,Id1=I1, Iq2,Id2=I2), which are transformed from the measured motor currents (IU1, IV1, IW1, IU2, IV2, IW2) into the two-dimensional d-q coordinate system in order to identify and remedy occurring faults.