Patent ID: 7136733
Filing Date: 2006-11-14
Classification: B62D,H02K,H02P

Abstract:
1. A method for detecting a fault in an electric power-assisted steering system, the method comprising the steps of: determining a voltage vector of an electric power-assisted steering motor; measuring a current vector of the electric power-assisted steering motor; defining an acceptable angular relationship between the voltage vector and the current vector; comparing an angle between the measured current vector and the determined voltage vector; indicating a fault if the angle does not meet the acceptable angular relationship; and detecting a rotational direction of the electric power-assisted steering motor, wherein the defining step includes a first acceptable angular relationship for a positive motor rotational direction where the angle of the voltage vector must lead the angle of the current vector, a second acceptable angular relationship for a negative motor rotational direction where the angle of the voltage vector must lag the angle of the current vector, and a third acceptable angular relationship for a substantially zero motor rotational direction where the angles of the voltage and current vectors are substantially in-phase.