System and method for determining a hitch angle offset

• US 9,434,414 B2
• Filed: 03/07/2014
• Issued: 09/06/2016
• Est. Priority Date: 04/19/2011
• 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
• Primary Examiner(s): Black, Thomas G
• Assistant Examiner(s): Kong, Sze-Hon
• Application Number:
  US14/200,886
• Publication Number:
  US 20140188346A1
• Time in Patent Office: 914 Days
• Field of Search: 701/28, 701/42
• US Class Current: 1/1
• CPC Class Codes: B60D 1/245 for facilitating push back or parking of trailers
• CPC Class Codes: B60Q 9/005 using a video camera
• CPC Class Codes: B60W 2520/22 Articulation angle, e.g. between tractor and trailer
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 30/18036 Reversing
• CPC Class Codes: B60W 40/10 related to vehicle motion
• CPC Class Codes: B62D 12/00 Steering specially adapted for vehicles operating in tandem or having pivotally connected frames steering endless tracks or the like B62D11/00; steering specially adapted for trailers B62D13/00
• CPC Class Codes: B62D 13/00 Steering specially adapted for trailers combined traction and steering hitches B60D
• CPC Class Codes: B62D 13/06 for backing a normally drawn trailer
• CPC Class Codes: B62D 15/02 Steering position indicators ; Steering position determination; Steering aids
• CPC Class Codes: B62D 15/027 Parking aids, e.g. instruction means
• CPC Class Codes: B62D 53/045 with rigid linkage in the horizontal plane luggage trailers B62D63/064 - B62D63/067
• CPC Class Codes: B62D 9/00 Steering deflectable wheels not otherwise provided for steering positon indicators B62D15/02

Abstract

A system and a method are provided for estimating an actual hitch angle between a vehicle and a trailer. A hitch sensor on the vehicle continuously senses a measured hitch angle and a steering sensor continuously senses a steering angle of steered wheels of the vehicle. A controller determines an offset between the measured hitch angle and the actual hitch angle when the measured hitch angle and the steering angle are substantially constant while the vehicle and trailer are reversing.

Claims

1. A method of estimating an actual hitch angle between a vehicle and a trailer, comprising:

sensing a measured hitch angle with a hitch angle sensor on the vehicle;

sensing a steering angle of steered wheels of the vehicle;

reversing the vehicle;

determining when the measured hitch angle and the steering angle are substantially constant while the vehicle is reversing; and

determining with a controller an offset between the measured hitch angle and the actual hitch angle when the measured hitch angle and the steering angle are determined to be substantially constant while the vehicle is reversing.

2. The method of claim 1, wherein the offset is determined as a function of a length of the trailer, a wheelbase length of the vehicle, and a distance from a rear axle of the vehicle to the trailer.

3. The method of claim 1, further comprising:

steering the reversing vehicle with a servomotor to move the vehicle and the trailer from the actual hitch angle to a desired hitch angle.

4. The method of claim 3, further comprising:

selecting the desired hitch angle between the vehicle and the trailer with a rotatable input control device and steering the vehicle in reverse based on the measured hitch angle, the offset, and the desired hitch angle.

5. The method of claim 1, further comprising:

selecting a desired hitch angle having zero curvature; and

steering the reversing vehicle based on the offset to position the vehicle and the trailer together in a straight line.

6. The method of claim 1, wherein the hitch angle sensor includes a video imaging camera that monitors a target on the trailer for continuously sensing the measured hitch angle.

7. The method of claim 1, wherein the offset is determined when the vehicle maintains a speed greater than a threshold speed for an increment of time.

8. A method of estimating an actual hitch angle between a vehicle and a trailer, comprising:

sensing with a hitch angle sensor a measured hitch angle continuously;

sensing a steering angle of the vehicle continuously;

determining when the measured hitch angle and the steering angle are substantially constant while the vehicle and the trailer are reversing over a threshold distance; and

determining with a controller an offset between the measured hitch angle and the actual hitch angle when the measured hitch angle and the steering angle are determined to be substantially constant while the vehicle is reversing over the threshold distance.

9. The method of claim 8, wherein the vehicle reverses over the threshold distance when the vehicle maintains a speed greater than a threshold speed for an increment of time.

10. The method of claim 9, wherein the increment of time is proportional to the speed, such that increasing the speed of the vehicle results in decreasing the increment of time the measured hitch angle and the steering angle must be substantially constant to determine the offset.

11. The method of claim 8, further comprising:

providing a length of the trailer, a wheelbase length of the vehicle, and a distance from a rear axle of the vehicle to the trailer, wherein the offset is determined by a controller based on the length of the trailer, the wheelbase length of the vehicle, and the distance from a rear axle of the vehicle to the trailer.

12. The method of claim 8, wherein the threshold distance is greater than half a circumference of a steered wheel of the vehicle.

13. The method of claim 8, further comprising:

steering the reversing vehicle based on the offset to move the vehicle and the trailer from the measured hitch angle to a desired hitch angle.

14. The method of claim 13, further comprising:

rotating an input control device to select the desired hitch angle between the vehicle and the trailer.

15. The method of claim 8, further comprising:

selecting a desired hitch angle having a substantially zero curvature; and

steering the reversing vehicle based on the offset to position the vehicle and the trailer together in a straight line.

16. The method of claim 8, wherein the measured hitch angle is continuously sensed with the hitch angle sensor that includes a video imaging camera that monitors movement of a target on the trailer.

17. A system for estimating an actual hitch angle between a vehicle and a trailer, comprising:

a hitch angle sensor continuously sensing a measured hitch angle;

a steering sensor continuously sensing a steering angle of the vehicle; and

a controller determining an offset between the measured hitch angle and the actual hitch angle when the measured hitch angle and the steering angle are determined to be substantially constant while the vehicle and the trailer are reversing.

18. The system of claim 17, wherein the offset is determined as a function of a length of the trailer, a wheelbase length of the vehicle, and a distance from a rear axle of the vehicle to the trailer.

19. The system of claim 18, wherein the offset is determined when the vehicle and the trailer each maintain a substantially constant yaw rate.

20. The system of claim 18, wherein the offset is determined when the vehicle and the trailer reverse over a threshold distance while maintaining the measured hitch angle and the steering angle at substantially constant values.