Abstract: A steering column assembly for a vehicle comprises an elongate steering column mounted for rotation about its longitudinal axis and configured for attachment of a steering wheel at one end. A first gear is connected to the steering column at a location spaced from where the steering wheel is attached and is configured to rotate with the steering column. The assembly has first and second motors, each having an output shaft and first and second worm screws directly connected to and rotatable with the output shaft of the first and second motors, respectively and engaged with the first gear, and a control arrangement is configured to operate the first and second motors. A motor position sensor arrangement senses the rotational position of the motor output shafts, each sensor arrangement comprising a target member fixedly mounted to a respective motor output shaft on an opposite side of the worm screw from the motor and a sensor for detecting the target member.

Abstract: A steering column assembly for a vehicle, comprises: an elongate steering column mounted for rotation about its longitudinal axis and configured for attachment to a steering wheel at one end; a first gear connected to the steering column at a location spaced from the one end to which the steering wheel is attached and configured to rotate with the steering column; first and second motors, each having an output shaft; first and second worm screws directly connected to and rotatable with the output shaft of the first and second motors respectively and engaged with the first gear; a control arrangement configured to operate the first and second motors; and a motor position sensor arrangement for sensing the rotational position of the motor output shafts, each sensor arrangement comprising a target member fixedly mounted to a respective motor output shaft on the opposite side of the worm screw from the motor and a sensor for detecting the target member.

Abstract: A method and apparatus diagnoses a correct operation of a phase or star point isolation relay in an electric power steering system of the kind including a motor drive circuit and at least one phase isolation relay which connects a part of the drive circuit to a phase of the motor. The relay is opened during shutdown to isolate the motor phase from the part of the drive circuit and is normally closed during operation of the motor to connect the phase to the part of the drive circuit.

Abstract: A method and apparatus diagnoses a correct operation of a phase or star point isolation relay in an electric power steering system of the kind including a motor drive circuit and at least one phase isolation relay which connects a part of the drive circuit to a phase of the motor. The relay is opened during shutdown to isolate the motor phase from the part of the drive circuit and is normally closed during operation of the motor to connect the phase to the part of the drive circuit.