Method and device for determining an angle of rotation and/or a rotational speed of a steering shaft

Patent metadata

Field	Value
Publication number	US-10065678-B2
Application number	US-201415100673-A
Country	US
Kind code	B2
Filing date	Nov 11, 2014
Priority date	Dec 13, 2013
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A method of determining an angle of rotation and/or a rotational speed of a motor shaft (110) of a motor (105) which is designed to produce a translational movement of a control element (115, 115a) relative to the motor (105). The method includes a step of reading in a movement signal via an interface with at least one sensor element (120) arranged outside the motor (105) such that the movement signal represents a translational movement of the control element (115) relative to the motor. In addition, the method further includes a step in which, using the movement signal, the angle of rotation and/or the rotational speed of the motor shaft (110) is/are determined.

First claim

The invention claimed is:

1. A method ( 400 ) of determining at least one of an angle of rotation (α) and a rotational speed (n) of a motor shaft ( 110 ) of a motor ( 105 ), the motor ( 105 ) being designed to produce a translational movement of a control element ( 115 ) relative to the motor ( 105 ), the method ( 400 ) comprises:
moving the control element axially along a rotational axis of the motor shaft by rotationally driving the motor shaft with the motor;
arranging at least one sensor element outside the motor and adjacent the rotational axis of the motor shaft to detect the translational movement of the control element relative to the motor;
reading ( 405 ) a movement signal, via an interface with the at least one sensor element ( 120 , 120 a ) that is arranged outside the motor ( 105 ), and the movement signal representing the translational movement of the control element ( 115 ) relative to the motor; and
determining ( 410 ), with a control unit, at least one of the angle of rotation (α) and the rotational speed (n) of the motor shaft ( 110 ) from the movement signal utilizing at least one of a linear conversion, an observer structure and a Kalman filter.

2. The method ( 400 ) according to claim 1 , further comprising determining a speed of the translational movement, from the movement signal, to determine the rotational speed (n) of the motor shaft in the determination step ( 410 ).

3. The method ( 400 ) according to claim 1 , further comprising, during the determination step ( 410 ), at least one of using a movement equation and taking into account a transmission ratio of a mechanical transmission chain, between the motor ( 105 ) and the control element ( 115 , 115 a ), for determining at least one of the angle of rotation (α) and the rotational speed (n).

4. The method ( 400 ) according to claim 1 , further comprising determining a motor shaft position, when the motor shaft ( 110 ) is at rest, and further, during the determination step ( 410 ), determining the angle of rotation (α) using the motor shaft position.

5. The method ( 400 ) according to claim 4 , further comprising acting upon the motor ( 105 ) by a test signal for determining the motor shaft position during the determination step.

6. The method ( 400 ) according to claim 4 , further comprising, during the determination step, at least temporarily blocking the control element ( 115 , 115 a ).

7. The method according to claim 4 , further comprising receiving a position signal, via the interface with the at least one sensor element ( 120 ), and the position signal represents an absolute position of the control element ( 115 , 115 a ) such that, during the determination step, a position of the motor shaft is checked using the position signal.

8. A device ( 500 ) for determining at least one of an angle of rotation (α) and a rotational speed (n) of a motor shaft ( 110 ) of a motor ( 105 ), such that the motor ( 105 ) being designed to move a control element ( 115 , 115 a ) in translation relative to the motor ( 105 ), the device ( 500 ) comprising:
the motor shaft being rotationally driven by the motor to axially move the control element along a rotational axis of the motor shaft;
at least one sensor element being arranged outside the motor and adjacent the rotational axis of the motor shaft to detect translational movement of the control element relative to the motor;
a read-in unit ( 506 ) for reading in a movement signal via an interface with the at least one sensor element ( 120 ) arranged outside the motor ( 105 ), and the movement signal represents the translational movement of the control element ( 115 , 115 a ) relative to the motor; and
a determination unit ( 510 ) for determining at least one of the angle of rotation (α) and the rotational speed (n) of the motor shaft ( 110 ), from the movement signal, utilizing at least one of a linear conversion, an observer structure and a Kalman filter.

9. A steering mechanism of a vehicle for steering either a front axle or a rear axle of the vehicle, the steering mechanism comprises:
a motor having a motor shaft that extends along a longitudinal axis, the motor driving the motor shaft to rotate about the longitudinal axis;
a control element being connected to the motor shaft such that rotation of the motor shaft about the longitudinal axis moves the control element in translation along the longitudinal axis relative to the motor, and a steering angle of the vehicle being adjusted by translational movement of the control element relative to the motor;
at least one sensor element being arranged outside the motor and adjacent the longitudinal axis for detecting the translational movement of the control element relative to the motor, the at least one sensor element emitting a movement signal, and the movement signal representing the translational movement of the control element relative to the motor; and
a control unit being connected to the at least one sensor element and having a read-in unit for reading in the movement signal emitted by the at least one sensor element, and the control unit having a determination unit for determining at least one of an angle of rotation of the motor shaft and a rotational speed of the motor shaft based on the movement signal utilizing at least one of a linear conversion, an observer structure and a Kalman filter.

Assignees

• Zahnradfabrik Friedrichshafen

Inventors

• Füssl Andreas
• Amann Notker

Classifications

• G01P3/00

  Measuring linear or angular speed; Measuring differences of linear or angular speeds (G01P5/00 - G01P11/00 take precedence; {direction and speed indication G01P13/045}; counting mechanisms G06M) · CPC title

• B62D15/0225 Primary

  by measuring on a steering gear element, e.g. on a rack bar · CPC title

• G01P3/44

  for measuring angular speed (G01P3/56 takes precedence) · CPC title

• B62D5/046

  Controlling the motor · CPC title