| US 7,454,986 B2 | ||
| Device and method for measuring torque in an electromechanical steering system | ||
| Olaf Kwasny, Salzgitter (Germany); Klaus Wahnschaffe, Wolfsburg/Hattorf (Germany); and Holger Manz, Sickte (Germany) | ||
| Assigned to Volkswagen Aktiengesellschaft, Wolfsburg (Germany) | ||
| Filed on Mar. 04, 2005, as Appl. No. 11/72,096. | ||
| Application 11/072096 is a continuation of application No. PCT/EP03/08038, filed on Jul. 23, 2003. | ||
| Claims priority of application No. 102 44 068 (DE), filed on Sep. 06, 2002. | ||
| Prior Publication US 2005/0182575 A1, Aug. 18, 2005 | ||
| Int. Cl. G01L 3/00 (2006.01) | ||
| U.S. Cl. 73—862.08 | 13 Claims |
| 1. A steering system comprising:
a steering device that is connected drive-wise to a steering mechanism via a torsion bar to an input and an output shaft part,
and an electrical servomotor to drive the steering mechanism, wherein the servomotor drive brings about a relative rotation
shift between the input shaft part and the output shaft part;
a main system for measuring torque in the torsion bar comprising a torque sensor; and
a backup system for measuring torque in the torsion bar comprising a sensor unit for obtaining the steering angle and a sensor
unit for obtaining the rotor angle of the servomotor and takes the form of a virtual torque sensor as well as allows the virtual
torque sensor to calculate the steering moment from the steering angle and the rotor angle, wherein the steering torque is
determined from the difference between the steering angle and the rotor angle.
|