METHOD AND APPARATUS FOR LIMITING AN ASSIST STEERING TORQUE

• US 20140222295A1
• Filed: 02/06/2014
• Published: 08/07/2014
• Est. Priority Date: 02/06/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: DORNHEGE, Jens, ENGELS, Frank Peters, WEGNER, Gtz-Philipp
• Granted Patent: US 10,053,144 B2
• Time in Patent Office: Days
• US Class Current: 701/42
• CPC Class Codes: B62D 6/002 computing target steering angles for front or rear wheels B62D7/159 takes precedence

Abstract

A method and apparatus for limiting assisting steering torque in a steering system having electronic power assisted steering is provided. In accordance with the method and apparatus, a steering angle change desired by the driver is determined and a range of valid steering angle changes dependent upon the steering angle change desired by the driver are defined. Subsequently it is determined whether a current steering angle change is included in the range of valid steering angle changes, and if the current steering angle change is not included in the range of the valid steering angle changes, the assisting steering torque is limited.

Claims

1. A method for limiting at least one assisting steering torque in a steering system having electronic power assisted steering, the method comprising:

determining a steering angle change desired by the driver;

defining a range of valid steering angle changes dependent upon the steering angle change desired by the driver;

checking whether a current steering angle change is included in the range of valid steering angle changes; and

limiting the assisting steering torque if the current steering angle change is not included in the range of the valid steering angle changes.

2. The method as claimed in claim 1, wherein a range of valid steering angle changes is defined for a plurality of vehicle velocities dependent upon the steering angle change that is desired by the driver;

and further comprising;

determining the current vehicle velocity; and

selecting a corresponding range of valid steering angle changes based on the vehicle velocity and based on the steering angle change that is desired by the driver prior to checking whether the current steering angle change desired by the driver is included in the range of valid steering angle changes.

3. The method as claimed in claim 1, wherein a magnitude of an assisting steering torque is reduced if the current steering angle change exceeds or falls short of the range of valid steering angle changes.

4. The method as claimed in claim 3, wherein an extent of the reduction of the magnitude of the assisting steering torque is reduced if the value of the current steering angle change falls within the range of valid steering angle changes.

5. The method as claimed in claim 1, further comprising determining a driver manual torque, wherein the steering angle change desired by the driver is represented by the driver manual torque.

6. The method as claimed in claim 1, wherein determining a steering angle change includes determining a rate of change of the steering angle.

7. The method as claimed in claim 1, further comprising adjusting the range of valid steering angle changes dependent upon driving conditions and/or driving situations.

8. The method of claim 7, wherein adjusting the range of valid steering angle changes includes extending, restricting or shifting the range based upon detected driving conditions or driving situations.

9. A system for limiting at least one assisting steering torque of a steering system having electronic power assisted steering, comprising:

a storage device configured to store a definition of a range of valid steering angle changes dependent upon a steering angle change desired by a driver;

a device for determining a steering angle change that results from a driver manual steering torque and a summation of steering torques of all requested steering torques of the electronic power assisted steering, and for outputting a signal that represents the resulting steering angle change;

a device for capturing a signal that represents the steering angle change desired by the driver;

a checking device for checking whether the steering angle change resulting from the driver manual steering torque and the summation of the steering torques of all the requested steering torques based on the steering angle change desired by the driver is included in a range of valid steering angle changes, wherein the checking device is operatively connected to the device for determining the steering angle change that results from the driver manual steering torque and the summation of the steering torques of all the requested steering torques, operatively connected to the device for capturing a signal that represents the steering angle change desired by the driver, and operatively connected to the storage device; and

a limiting device for limiting an assisting steering torque if the check indicates that a steering angle change resulting from the driver manual steering torque and the summation of the steering torques of all the requested steering torques based on the steering angle change that is desired by the driver is not included in the range of valid steering angle changes.

10. The system as claimed in claim 9, wherein the storage device is configured to store a definition of a range of valid steering angle changes dependent upon the steering angle change desired by the driver for each of a plurality of vehicle velocities, and further comprising:

a device for capturing a signal that represents a current vehicle velocity, wherein the device for capturing a signal that represents the current vehicle velocity is operatively connected to the checking device; and

wherein the checking device comprises a selector device that selects a corresponding range of valid steering angle changes based upon the steering angle change desired by the driver and based upon the current vehicle velocity.

11. The system as claimed in claim 9, wherein the signal that represents the steering angle change desired by the driver is a signal that represents a driver manual torque.

12. The system as claimed in claim 9, wherein the signal that represents the resulting steering angle change is a signal that represents a rate of change of steering angle.

13. The system as claimed in claim 9, further comprising a situation recognition device configured to detect a presence of a driving maneuver and/or a driving condition.

14. The system as claimed in claim 13, wherein the situation recognition device is further configured to extend, restrict, or shift the range of valid steering angle changes based on the detected driving maneuver and/or the detected driving condition.