Steering angle detection by means of ESC and EPAS

• US 20080119987A1
• Filed: 11/21/2007
• Published: 05/22/2008
• Est. Priority Date: 11/22/2006
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Frese, Thomas, Thoene, Alois, Hestermeyer, Thorsten Wilhelm
• Granted Patent: US 8,515,621 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B62D 15/021 Determination of steering angle
• CPC Class Codes: B62D 15/0235 by measuring or deriving directly at the electric power steering motor
• CPC Class Codes: B62D 5/0493 detecting processor errors, e.g. plausibility of steering direction

Abstract

The invention relates to a method for detecting a steering wheel position of a motor vehicle which has an evaluation unit and a servo-assisted steering device, a position sensor being assigned to the servo-assisted steering device. After loss of an on-board power system voltage, the servo-assisted steering device conducts a steering angle value which is absolute at least in one circular segment to the evaluation unit. The evaluation unit detects an absolute steering angle position which is transmitted to the servo-assisted steering device which accepts the absolute value obtained from the evaluation unit. The servo-assisted steering device continues to monitor the absolute steering angle even when the ignition is switched off, and it conducts the current value to the evaluation unit in the switched-on state of the motor vehicle so that the evaluation unit checks the plausibility of the value obtained from the servo-assisted steering device and conducts it back to the servo-assisted steering device which accepts the obtained value.

Claims

1. A method for detecting a steering wheel position of a motor vehicle after loss of an on board power system voltage, the motor vehicle having an evaluation unit and a servo-assisted steering device, the servo-assisted steering device having a position sensor, the method comprising the following steps:

the servo-assisted steering device communicates a steering angle value which is absolute at least in one circular segment to the evaluation unit during the switched on state of the motor vehicle, and

the evaluation unit determines an absolute steering angle position which is transmitted to the servo-assisted steering device which accepts the absolute value obtained from the evaluation unit.

2. The method as claimed in claim 1, wherein the evaluation unit is networked to the servo-assisted steering device.

3. The method as claimed in claim 2, including the further step of the servo-assisted steering device superimposing a quality factor on the absolute steering angle transmitted to the evaluation unit.

4. The method as claimed in claim 3, further comprising the step of the evaluation unit checking the plausibility of the absolute steering angle transmitted to it.

5. The method as claimed in claim 4, wherein the evaluation unit uses the yaw rate, wheel speed, and lateral acceleration of the motor vehicle to check the plausibility of the absolute steering angle transmitted to it.

6. The method as claimed in claim 5, wherein the absolute steering angle transmitted from the evaluation unit to the servo-assisted steering device comprises at least one plausibility checked absolute steering angle.

7. The method as claimed in claim 6, further comprises the step of the servo-assisted steering device adapts the steering wheel position signal monitored by it to a plausibility checked absolute steering angle transmitted to it by the evaluation unit.

8. A method for detecting a steering wheel position of a motor vehicle having an evaluation unit and a servo-assisted steering device, the servo-assisted steering device having a position sensor, the method comprising the following steps:

the servo-assisted steering device monitors the absolute steering angle even when the ignition is switched off;

the servo-assisted steering device communicates a steering angle value which is absolute at least in one circular segment to the evaluation unit in the switched on state of the motor vehicle, and

the evaluation unit determines an absolute steering angle position which is transmitted to the servo-assisted steering device which accepts the absolute value obtained from the evaluation unit.

9. The method as claimed in claim 8, wherein the evaluation unit is networked to the servo-assisted steering device.

10. The method as claimed in claim 9, including the further step of the servo assisted steering device superimposing a quality factor on the absolute steering angle transmitted to the evaluation unit.

11. The method as claimed in claim 10, further comprising the step of the evaluation unit checking the plausibility of the absolute steering angle transmitted to it.

12. The method as claimed in claim 11, wherein the evaluation unit uses the yaw rate, wheel speed, and lateral acceleration of the motor vehicle to check the plausibility of the absolute steering angle transmitted to it.

13. The method as claimed in claim 12, wherein the absolute steering angle transmitted from the evaluation unit to the servo-assisted steering device comprises at least one absolute steering angle checked for plausibility.

14. The method as claimed in claim 13, further comprises the step of the servo-assisted steering device adapting the steering wheel position signal monitored by it to a plausibility checked absolute steering angle transmitted to it by the evaluation unit.