Trailer backup assist system with hitch angle offset estimation

• US 10,384,607 B2
• Filed: 10/18/2016
• Issued: 08/20/2019
• Est. Priority Date: 10/19/2015
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Lavoie, Erick Michael, Mattern, Donald Jacob, Raad, Joseph M., Daavettila, Tyler, Bell, Robert
• Primary Examiner(s): Anderson, II, James M
• Application Number:
  US15/296,638
• Publication Number:
  US 20170106796A1
• Time in Patent Office: 1,036 Days
• Field of Search: None
• CPC Class Codes: B60R 2300/207 using multi-purpose displays, e.g. camera image and navigation or video on same display
• CPC Class Codes: B60R 2300/302 combining image information with GPS information or vehicle data, e.g. vehicle speed, gyro, steering angle data
• CPC Class Codes: B60R 2300/8086 for vehicle path indication
• CPC Class Codes: B62D 13/06 for backing a normally drawn trailer
• CPC Class Codes: G01B 11/272 using photoelectric detection means

Abstract

A system for estimating hitch angle offset is provided herein. A sensor system is configured to measure hitch angles between a vehicle and a trailer attached thereto. A controller is configured to calculate hitch angle offsets for a plurality of measured hitch angles, and extrapolate additional hitch angle offsets based on the calculated hitch angle offsets.

Claims

1. A system for estimating hitch angle offset comprising:

a sensor system configured to measure hitch angles between a vehicle and a trailer attached thereto; and

a controller configured to;

calculate hitch angle offsets for a plurality of measured hitch angles;

extrapolate additional hitch angle offsets based on the calculated hitch angle offsets; and

assist with guiding the vehicle to reverse the trailer on a backing path based on the extrapolated additional hitch angle offsets.

2. The system of claim 1, wherein the sensor system comprises a camera of the vehicle that monitors a target on the trailer.

3. The system of claim 1, wherein each of the hitch angle offsets are calculated when a corresponding measured hitch angle is substantially constant.

4. The system of claim 1, wherein each of the hitch angle offsets are calculated as a function of a trailer length, a wheelbase length, a drawbar length, and a steering angle.

5. The system of claim 1, wherein each of the hitch angle offsets are calculated when a yaw rate of the vehicle and the trailer are substantially equal and constant.

6. The system of claim 1, wherein the controller performs a curve fit between the calculated hitch angle offsets to estimate the additional hitch angle offsets, the additional hitch angle offsets being related to measurable hitch angles for operating a trailer backup assist system.

7. The system of claim 6, wherein the curve fit is one of a linear function and a higher order function.

8. A system for estimating hitch angle offset comprising:

a sensor system configured to measure hitch angles between a vehicle and a trailer attached thereto; and

a controller configured to;

calculate hitch angle offsets for a plurality of measured hitch angles when a yaw rate of the vehicle and the trailer are substantially equal and constant;

extrapolate additional hitch angle offsets based on the calculated hitch angle offsets; and

assist with guiding the vehicle to reverse the trailer on a backing path based on the extrapolated additional hitch angle offsets.

9. The system of claim 8, wherein the sensor system comprises a camera of the vehicle that monitors a target on the trailer.

10. The system of claim 8, wherein each of the hitch angle offsets are calculated when a corresponding measured hitch angle is substantially constant.

11. The system of claim 8, wherein each of the hitch angle offsets are calculated as a function of a trailer length, a wheelbase length, a drawbar length, and a steering angle.

12. The system of claim 8, wherein the controller performs a curve fit between the calculated hitch angle offsets to estimate the additional hitch angle offsets, the additional hitch angle offsets being related to measurable hitch angles for operating a trailer backup assist system.

13. The system of claim 12, wherein the curve fit is one of a linear function and a higher order function.

14. A method for estimating hitch angle offset comprising the steps of:

measuring hitch angles between a vehicle and a trailer attached thereto;

calculating hitch angle offsets for the measured hitch angles;

extrapolating additional hitch angle offsets based on the calculated hitch angle offsets; and

assisting with guiding the vehicle to reverse the trailer on a backing path based on the extrapolated additional hitch angle offsets.

15. The method of claim 14, wherein the hitch angles are measured by a camera of the vehicle that monitors a target on the trailer.

16. The method of claim 14, wherein each of the hitch angle offsets are calculated when a corresponding measured hitch angle is substantially constant.

17. The method of claim 14, wherein each of the hitch angle offsets are calculated as a function of a trailer length, a wheelbase length, a drawbar length, and a steering angle.

18. The method of claim 14, wherein each of the hitch angle offsets are calculated when a yaw rate of the vehicle and the trailer are substantially equal and constant.

19. The method of claim 14, wherein the step of extrapolating comprises performing a curve fit between the calculated hitch angle offsets to estimate the additional hitch angle offsets, the additional hitch angle offsets being related to measurable hitch angles for operating a trailer backup assist system.

20. The method of claim 19, wherein the curve fit is one of a linear function and a higher order function.