DETERMINATION OF STEERING ANGLE FOR A MOTOR VEHICLE

• US 20130151066A1
• Filed: 09/09/2011
• Published: 06/13/2013
• Est. Priority Date: 09/09/2010
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Koukes, Vladimir, Schmidt, Robert, Niepelt, Mathias, Herbst, Ralf, Fhrer, Jochen
• Granted Patent: US 9,330,061 B2
• Time in Patent Office: Days
• US Class Current: 701/34.4
• CPC Class Codes: B60T 2250/06 Sensor zero-point adjustment; Offset compensation
• CPC Class Codes: B60T 2270/86 Optimizing braking by using ESP vehicle or tire model
• CPC Class Codes: B60T 8/17551 determining control parameters related to vehicle stability used in the regulation, e.g. by calculations involving measured or detected parameters
• CPC Class Codes: B62D 15/0245 Means or methods for determination of the central position of the steering system, e.g. straight ahead position
• CPC Class Codes: G06F 17/00 Digital computing or data processing equipment or methods, specially adapted for specific functions information retrieval, database structures or file system structures therefor G06F16/00

Abstract

Method and control device for determining a steering angle of a motor vehicle, wherein a theoretical steering angle is calculated by a vehicle model and a measured steering angle is determined with a steering angle sensor, and the difference between the measured and theoretical steering angles is determined, wherein at least one data record including a number of successive measured values is acquired, and a correction constant for the measured steering angle is determined from the mean value of the differences between the theoretical steering angle and the measured steering angle. According to the invention, a confidence level, which changes incrementally between successive data records, is calculated by travel conditions present during the acquisition of the data record and/or an analysis of the data record.

Claims

1-17. -17. (canceled)

18. A method in which the steering angle of a motor vehicle is determined, wherein a theoretical steering angle is calculated by a vehicle model and a measured steering angle is determined with a steering angle sensor, and a difference between the measured and theoretical steering angles is determined, wherein at least one data record comprising a number of successive measured values is acquired, and a correction constant for the measured steering angle is determined from a mean value of the differences between the theoretical steering angle and the measured steering angle, wherein a confidence level, which changes incrementally between successive data records, is calculated by travel conditions present during the acquisition of the data record and/or an analysis of the data record.

19. The method as claimed in claim 18, wherein a corrected steering angle is determined from the measured steering angle and the correction constant and is passed on to other vehicle systems, in particular a system for vehicle dynamics control when the confidence level exceeds a first threshold value.

20. The method as claimed in claim 18, wherein the determination of new correction constants is ended for the duration of an ignition run if the confidence level exceeds a second threshold value.

21. The method as claimed in claim 18, wherein a standard deviation of the determined differences and/or a correlation coefficient between the theoretical steering angle and the measured steering angle are/is calculated in an analysis of the data record.

22. The method as claimed in claim 21, wherein possible errors of the correction constant are estimated by a confidence interval which depends on the standard deviation of the determined differences and preferably of the confidence level.

23. (New The method as claimed in claim 21, wherein the correction constant is determined from a data record only if the confidence interval undershoots a third threshold value and/or the correlation coefficient exceeds a fourth threshold value.

24. The method as claimed in claim 21, wherein the confidence level is increased if, or only if, the confidence interval undershoots a fifth threshold value and/or the correlation coefficient exceeds a sixth threshold value.

25. The method as claimed in claim 21, wherein a plurality of data records are determined and evaluated, and the confidence level is increased if deviations between the correction constants which are determined from the individual data records and/or calculated correlation coefficients and/or confidence intervals dependent at least on the standard deviation of the determined differences undershoot/undershoots a seventh threshold value.

26. The method as claimed in claim 18, wherein information relating to one or more of the following travel conditions:

a speed of the vehicle, an activity of driving stability control systems, a yaw rate, a lateral acceleration, a change in the yaw rate over time, a longitudinal travel direction, an inclination of the vehicle, a change in the steering angle over time are evaluated for the determination of the confidence level.

27. The method as claimed in claim 26, wherein the confidence level is increased if, or only if, the travel conditions correspond to stable straight-ahead travel or cornering without interventions by driving stability control systems.

28. The method as claimed in claim 18, wherein when an ignition run ends, the corrected steering angle determined last is stored in a nonvolatile memory module, and when a subsequent ignition run starts it is read out as a starting value.

29. The method as claimed in claim 28, wherein at the start of the subsequent ignition run one or more new data records are determined and the deviation between a certain correction constant or certain correction constants and the starting value is calculated, and the confidence level is incremented to a predefined value if the deviation between a certain correction constant and the starting value undershoots an eighth threshold value.

30. A control unit for determining a steering angle of a vehicle which receives at least information about a steering angle, a yaw rate and a vehicle speed via a vehicle data bus or a means for inter-process communication, wherein a memory which can accommodate a plurality of chronologically successive data records, and at least one processor which evaluates the data records according to a method in which the steering angle of a motor vehicle is determined, wherein a theoretical steering angle is calculated by a vehicle model and a measured steering angle is determined with a steering angle sensor, and a difference between the measured and theoretical steering angles is determined, wherein at least one data record comprising a number of successive measured values is acquired, and a correction constant for the measured steering angle is determined from a mean value of the differences between the theoretical steering angle and the measured steering angle, wherein a confidence level, which changes incrementally between successive data records, is calculated by travel conditions present during the acquisition of the data record and/or an analysis of the data record.

31. The control unit as claimed in claim 30, wherein at least one yaw rate sensor is integrated into the control unit, and the control unit comprises a means for receiving raw data of a steering wheel angle sensor.

32. The control unit as claimed in claim 30, wherein the control unit comprises at least one hydraulic valve and at least one electric pump, and the control unit comprises at least one system, a traction control and/or a vehicle dynamics control for driving stability control.

33. The control unit as claimed in claim 30, wherein the correction constant and/or a measure of possible errors in the correction constant are/is passed on via the vehicle data bus or means for inter-process communication, to a driving stability control system.

34. The control unit as claimed in claim 30, wherein information relating to one or more of the following travel conditions, a speed of the vehicle, an activity of driving stability control systems, a yaw rate, a lateral acceleration, a change in the yaw rate over time, a longitudinal direction of travel, an inclination of the vehicle, a change in the steering angle over time, are received from a further control unit, via the vehicle data bus.

35. The control unit as claimed in claim 34, wherein the further vehicle control unit is at least one of a navigation system and a sensor cluster.