VEHICLE YAW RATE CORRECTION

• US 20130231825A1
• Filed: 02/28/2013
• Published: 09/05/2013
• Est. Priority Date: 03/01/2012
• Status: Active Grant

• Current Assignee: Magna Electronics Incorporated (Magna International Incorporated)
• Original Assignee: Magna Electronics Incorporated (Magna International Incorporated)
• Inventors: Chundrlik, William J. Jr., Johnson, Nathaniel, Wimmershoff, Marc
• Granted Patent: US 8,694,224 B2
• Time in Patent Office: Days
• US Class Current: 701/29.1
• CPC Class Codes: B60R 1/24 in front of the vehicle
• CPC Class Codes: B60R 2300/804 for lane monitoring
• CPC Class Codes: B60T 7/12 for automatic initiation; for initiation not subject to will of driver or passenger limiting speed of vehicles other than rail vehicles B60K31/00
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: B60W 2050/0049 Signal offset
• CPC Class Codes: B60W 2420/403 Image sensing, e.g. optical camera
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 30/08 Active safety systems predicting or avoiding probable or impending collision or attempting to minimise its consequences
• CPC Class Codes: B60W 30/12 Lane keeping
• CPC Class Codes: B60W 40/114 Yaw movement
• CPC Class Codes: B60W 50/0098 Details of control systems ensuring comfort, safety or stability not otherwise provided for
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/024 Special manufacturing steps or sacrificial layers or layer structures
• CPC Class Codes: G01J 5/34 using capacitors, e.g. pyroelectric capacitors
• CPC Class Codes: G01P 13/00 Indicating or recording presence, absence, or direction, of movement electric switches H01H; counting moving objects G06M7/00
• CPC Class Codes: G01P 3/50 for measuring linear speed G01P3/56 takes precedence
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road
• CPC Class Codes: G07C 5/02 Registering or indicating driving, working, idle, or waiting time only apparatus forming part of taximeters G07B13/00
• CPC Class Codes: G07C 5/08 Registering or indicating performance data other than driving, working, idle, or waiting time, with or without registering driving, working, idle or waiting time
• CPC Class Codes: H04N 23/80 : Camera processing pipelines; Components thereof
• CPC Class Codes: H04N 25/76 : Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: H04N 7/183 : for receiving images from a single remote source

Abstract

A control system or method for a vehicle references a camera and sensors to determine when an offset of a yaw rate sensor may be updated. The sensors may include a longitudinal accelerometer, a transmission sensor, a vehicle speed sensor, and a steering angle sensor. The offset of the yaw rate sensor may be updated when the vehicle is determined to be stationary by referencing at least a derivative of an acceleration from the longitudinal accelerometer. The offset of the yaw rate sensor may be updated when the vehicle is determined to be moving straight by referencing at least image data captured by the camera. Lane delimiters may be detected in the captured image data and evaluated to determine a level of confidence in the straight movement. When the offset of the yaw rate sensor is to be updated, a ratio of new offset to old offset may be used.

Claims

1. A method for determining a yaw rate for a road-based vehicle having a yaw rate sensor, the method comprising:

(a) capturing image data representative of the environment exterior of the vehicle;

(b) determining if the vehicle is moving and has a zero yaw rate at least based on processing of captured image data;

(c) obtaining a first measured yaw rate from the yaw rate sensor when the vehicle is determined in step (b) to be moving and to have a zero yaw rate;

(d) determining a yaw rate offset based at least in part on the measured yaw rate obtained in step (c);

(e) obtaining a second measured yaw rate from the yaw rate sensor; and

(f) determining a corrected yaw rate for the vehicle based on the second measured yaw rate and the yaw rate offset.

2. The method of claim 1, wherein step (b) includes:

(g) determining, at least from image processing of captured image data that the vehicle is driving straight.

3. The method of claim 2, wherein step (b) further includes:

(h) detecting any lane delimiters present in the exterior scene represented by the captured image data;

(i) determining whether any lane delimiters detected in step (h) are qualifying lane delimiters which meet selected criteria; and

(j) comparing a heading of the vehicle with the direction of at least one qualifying lane delimiter.

4. The method of claim 3, wherein when there are two qualifying lane delimiters, step (j) includes comparing a heading of the vehicle with the direction of the two qualifying lane delimiters.

5. The method of claim 3, wherein step (i) includes determining whether the amount of curvature in any lane delimiters detected in step (h) is below a selected threshold amount of curvature.

6. The method of claim 3, wherein step (i) includes determining whether any lane delimiters detected in step (h) have been detected for more than a selected duration.

7. The method of claim 3, wherein the yaw rate offset is a first selected proportion of the measured yaw rate obtained in step (c) and a second selected proportion of a previous yaw rate offset, and wherein the first and second selected proportions are selected based at least in part on how many lane delimiters meet the selected criteria.

8. The method of claim 1, wherein step (b) includes determining whether a steering angle of the vehicle is less than a selected threshold steering angle.

9. The method of claim 1, wherein step (b) includes determining whether the speed of the vehicle is greater than a selected threshold speed.

10. The method of claim 1, wherein step (b) includes determining whether the steering angle of the vehicle is approximately zero.

11. The method of claim 1, wherein the yaw rate offset is a first selected proportion of the measured yaw rate obtained in step (c) and a second selected proportion of a previous yaw rate offset.

12. The method of claim 1, wherein a system of a vehicle is operable to control the operation of at least one brake on the vehicle based on the determined corrected yaw rate obtained.

13. A method for determining a yaw rate for a road-based vehicle having a yaw rate sensor, the method comprising:

(a) obtaining an acceleration from an accelerometer positioned to sense a longitudinal acceleration of the vehicle;

(b) determining a rate of change of the acceleration;

(c) carrying out a determination of a yaw rate offset based at least in part on a first measured yaw rate from the yaw rate sensor, at least in part depending on whether the rate of change of the acceleration determined in step (b) is approximately zero;

(d) obtaining a second measured yaw rate from the yaw rate sensor; and

(e) determining a corrected yaw rate for the vehicle based on the second measured yaw rate and the yaw rate offset.

14. The method of claim 13, wherein step (c) is carried out depending at least in part on whether the rate of change of the acceleration determined in step (b) is approximately zero for a selected duration.

15. The method of claim 13, wherein step (c) is carried out depending in part on a determination of whether the vehicle has a speed that is approximately zero.

16. The method of claim 13, wherein the yaw rate offset is a first selected proportion of the measured yaw rate obtained in step (c) and a second selected proportion of a previous yaw rate offset.

17. The method of claim 13, wherein a system of a vehicle is operable to control the operation of at least one brake on the vehicle based on the determined corrected yaw rate obtained.

18. A method for determining a yaw rate for a road-based vehicle having a yaw rate sensor and at least one other sensor, the method comprising:

(a) determining whether the vehicle has a yaw rate of zero;

(b) obtaining a first measured yaw rate from the yaw rate sensor depending on the determination made in step (a);

(c) determining a yaw rate offset that is a first selected proportion of the first measured yaw rate obtained in step (b) and a second selected proportion of a previous yaw rate offset, wherein the first selected proportion and the second selected proportion are selected based on a set of criteria based on data determined from the at least one other sensor;

(d) obtaining a second measured yaw rate from the yaw rate sensor; and

(e) determining a corrected yaw rate for the vehicle based on the second measured yaw rate and the yaw rate offset.

19. The method of claim 18, wherein the data includes a derivative of longitudinal acceleration for the vehicle and wherein the set of criteria includes whether the derivative of the longitudinal acceleration for the vehicle is approximately zero.

20. The method of claim 18, wherein the ratio of the first and second selected proportions varies between about 1:

99 and about 1;

9.

21. The method of claim 18, wherein the at least one sensor includes a vehicle-mounted camera and wherein the data includes image data captured by the vehicle-mounted camera and representative of the environment exterior of the vehicle.

22. The method of claim 21, wherein the set of criteria includes the number of lane delimiters detected in the captured image data.

23. The method of claim 18, wherein a system of a vehicle is operable to control the operation of at least one brake on the vehicle based on the determined corrected yaw rate obtained.