Process for determining vehicle dynamics

• US 6,130,706 A
• Filed: 09/08/1998
• Issued: 10/10/2000
• Est. Priority Date: 03/25/1998
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Kordys, Matthew A., Nalwa, Vishvjit Singh, Hart, Arthur Clifford Jr., Pingali, Sarma VGK
• Primary Examiner(s): Kelley, Chris S.
• Assistant Examiner(s): An, Shawn S.
• Application Number:
  US09/149,372
• Time in Patent Office: 763 Days
• Field of Search: 348/148, 340/439, 340/576, 364/559, 364/424, 364/905, 364/913, 303/111
• US Class Current: 348/148
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60W 40/103 Side slip angle of vehicle body
• CPC Class Codes: G01P 13/045 with speed indication
• CPC Class Codes: G01P 3/38 using photographic means
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle

Abstract

A process for determining at least one dynamic of a vehicle, particularly slip angle, during travel. The process involves optically monitoring, in real time and from the vehicle itself, the movement in one or more camera images of surface features as the vehicle passes over the surface. The direction in which the surface features are moving at any given time indicates the actual direction of vehicle movement with respect to the orientation of the optical monitoring equipment. From this actual direction of movement, in combination with the known orientation of the optical monitoring equipment and the direction in which the vehicle is being steered, it is possible to calculate the slip angle in real time.

Claims

1. A process for determining a vehicle dynamic during travel, comprising the steps of:

monitoring movement in one or more camera images of features in a surface over which a vehicle is traveling; and

analyzing the movement to determine at least one vehicle dynamic by analyzing the texture of the features in a single camera frame image, wherein the texture analysis comprises;

identifying edges or points of high image intensity gradient in the camera frame image;

calculating the orientation of an edge segment associated with the edges or points of high image intensity gradient; and

determining a dominant orientation of the edge segments.

2. The process of claim 1, wherein the analysis determines the direction of vehicle movement.

3. The process of claim 2, wherein the analysis determines the speed of the vehicle.

4. The process of claim 1, wherein the step of monitoring is performed with a camera mounted such that the camera maintains alignment with a wheel of the vehicle.

5. The process of claim 1, at least, two cameras are mounted to the vehicle to monitor the movement of the features.

6. The process of claim 1, wherein the at least one vehicle dynamic includes slip angle.

7. The process of claim 1, further comprising the step of monitoring steering angle.

8. The process of claim 1, wherein the step of analyzing further comprises:

calculating the angle of vehicle motion; and

determining slip angle from the angle of vehicle motion.

9. A process for determining a vehicle dynamic during travel, comprising the steps of:

monitoring movement in one or more camera images of features in a surface over which a vehicle is traveling; and

analyzing the movement to determine at least one vehicle dynamic by analyzing the texture of the features in a single camera frame image, wherein the camera shutter speed, t_s, falls within the range ##EQU9## where l is the field of view of the camera in a steering direction of the vehicle and v is vehicle velocity.

10. A process for determining a vehicle dynamic during travel, comprising the steps of:

monitoring movement in a plurality of consecutive camera images of features in a surface over which a vehicle is traveling; and

analyzing the movement to determine at least one vehicle dynamic, wherein the step of monitoring movement comprises monitoring individual features of the surface in at least two consecutive camera frame images, and wherein the camera is operated at a shutter speed of less than ##EQU10## where l is the field of view in a steering direction of the vehicle, n is the number of pixels in the image plane along the steering direction, and v is the speed of the vehicle.

11. The process of claim 10, wherein the step of analyzing comprises:

matching individual features in the at least two consecutive images;

determining motion vectors for the matched features; and

determining a dominant motion vector.

12. The process of claim 11, wherein the step of analyzing further comprises:

calculating the angle of vehicle motion; and

determining slip angle from the angle of vehicle motion and a reference angle.

13. A process for determining a vehicle dynamic during travel, comprising the steps of:

monitoring movement in one or more camera images of features in a surface over which a vehicle is traveling; and

analyzing the movement to determine at least one vehicle dynamic, wherein the step of monitoring movement is performed with at least one strobe light in combination with a camera such that at least two strobe flashes are performed during a single camera frame exposure, and wherein the strobe flashes are separated by a period ranging from ##EQU11## and the camera is operated at a shutter speed ranging from ##EQU12## where l is the field of view in a steering direction of the vehicle and v is the speed of the vehicle.

14. The process of claim 13 wherein the step of analyzing comprises:

matching individual features within the single camera frame image;

determining motion vectors for the matched features; and

determining a dominant motion vector.

15. The process of claim 14, wherein the step of analyzing further comprises:

calculating the angle of vehicle motion; and

determining slip angle from the angle of vehicle motion and a reference angle.

16. A vehicle comprising an apparatus for determining a vehicle dynamic during travel, wherein the apparatus is capable of monitoring movement in one or more camera images of features in a surface over which a vehicle is traveling, and analyzing the movement to determine at least one vehicle dynamic by analyzing the texture of the features in a single camera frame image, wherein the texture analysis comprises:

identifying edges or points of high image intensity gradient in the camera frame image;

calculating the orientation of an edge segment associated with the edges or points of high image intensity gradient; and

determining a dominant orientation of the edge segments.

17. The vehicle of claim 16, wherein the step of monitoring movement is performed with at least one strobe light in combination with a camera such that at least two strobe flashes are performed during a single camera frame exposure.

18. The vehicle of claim 17, wherein the step of analyzing further comprises:

matching individual features within the single camera frame image;

determining motion vectors for the matched features; and

determining a dominant motion vector.

19. A vehicle comprising an apparatus for determining a vehicle dynamic during travel, wherein the apparatus includes a camera and is capable of monitoring movement in a plurality of consecutive camera images of features in a surface over which a vehicle is traveling, and of analyzing the movement to determine at least one vehicle dynamic, wherein the step of monitoring movement comprises monitoring individual features of the surface in at least two of the consecutive camera frame images, and wherein the camera is operated at a shutter speed of less than ##EQU13## where l is the field of view in a steering direction of the vehicle, n is the number of pixels in the image plane along the steering direction, and v is the speed of the vehicle.

20. The vehicle of claim 19, wherein the step of analyzing comprises:

matching individual features in the at least two consecutive images;

determining motion vectors for the matched features; and

determining a dominant motion vector.