Trailer length estimation in hitch angle applications

• US 9,290,203 B2
• Filed: 06/11/2014
• Issued: 03/22/2016
• 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, Kyrtsos, Christos
• Primary Examiner(s): To, Tuan C.
• Assistant Examiner(s): Hilgendorf, Dale W
• Application Number:
  US14/302,035
• Publication Number:
  US 20140297129A1
• Time in Patent Office: 650 Days
• US Class Current: 1/1
• CPC Class Codes: B60D 1/245 for facilitating push back or parking of trailers
• CPC Class Codes: B60D 1/62 involving supply lines, electric circuits, or the like
• CPC Class Codes: B60W 30/00 Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
• 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 15/027 Parking aids, e.g. instruction means
• CPC Class Codes: G01B 21/02 for measuring length, width, or thickness G01B21/10 takes precedence
• CPC Class Codes: G01B 21/06 specially adapted for measuring length or width of objects while moving

Abstract

A vehicle system for estimating a trailer length is disclosed and includes a first sensor for measuring a wheel steer angle and a second sensor for measuring a hitch angle. A processor is in communication with the at least one sensor and is operable to determine a ratio between the wheel steer angle and the hitch angle, generate a running average of the ratio, and calculate the trailer length based on an average ratio between the wheel steer angle and the hitch angle.

Claims

1. A device for estimating a trailer length, comprising:

a processor in communication with a wheel steer angle sensor and a hitch angle sensor, the processor operable to;

determine an average ratio between a wheel steer angle and a hitch angle; and

calculate the trailer length by fitting the average ratio to a predictive model and setting the trailer length to a trailer length value that is assigned to a ratio value matching the average ratio.

2. The device of claim 1, wherein the wheel steer angle and the hitch angle are determined when an axle center-line of a trailer is aligned with a center of rotation of a vehicle towing the trailer.

3. The device of claim 1, wherein the processor additionally calculates the trailer length using a linear equation having as input the average ratio, a wheel base distance, a vehicle track width, and a hitch point to rear axle center-line distance.

4. The device of claim 1, wherein the processor additionally calculates the trailer length by matching the average ratio to a ratio value in a look up table and setting the trailer length to a trailer length value associated with the ratio value.

5. The device of claim 4, wherein the look up table comprises a first set of ratio values, a second set of ratio values, and an associated trailer length value assigned to each ratio value in the first and second sets of ratio values.

6. The device of claim 5, wherein the first set of ratio values correspond to ratio values determined using a first computation and the second set of ratio values correspond to ratio values determined using a second computation.

7. A vehicle system for estimating a trailer length, comprising:

a first sensor for measuring a wheel steer angle and a second sensor for measuring a hitch angle; and

a processor operable to;

determine an average ratio between the wheel steer angle and the hitch angle; and

calculate the trailer length by matching the average ratio to a ratio value in a look up table and setting the trailer length to a trailer length value associated with the ratio value.

8. The vehicle system of claim 7, wherein the processor calculates the trailer length using a linear equation having as input the average ratio, a wheel base measurement, a vehicle track width, and a hitch point to rear axle center-line distance.

9. The vehicle system of claim 7, wherein the processor additionally calculates the trailer length by fitting the average ratio to a predictive model and setting the trailer length to a trailer length value that is assigned to a ratio value matching the average ratio.

10. The vehicle system of claim 7, wherein the look up table comprises a first set of ratio values, a second set of ratio values, and an associated trailer length value assigned to each ratio value in the first and second sets of ratio values.

11. The vehicle system of claim 10, wherein the first set of ratio values correspond to ratio values determined using a first computation and the second set of ratio values correspond to ratio values determined using a second computation.

12. The vehicle system of claim 7, wherein the wheel steer angle and the hitch angle are determined when an axle center-line of a trailer is aligned with a center of rotation of a vehicle towing the trailer.

13. A method for estimating a trailer length, comprising the steps of:

measuring a wheel steer angle with a first sensor;

measuring a hitch angle with a second sensor; and

providing a processor for;

determining an average ratio between the wheel steer angle and the hitch angle; and

calculating the trailer length by matching the average ratio to a ratio value in a look up table and setting the trailer length to a trailer length value associated with the ratio value.

14. The method of claim 13, further comprising the step of aligning an axle center-line of a trailer with a center of rotation of a vehicle towing the trailer.

15. The method of claim 13, wherein the step of calculating the trailer length additionally comprises using a linear equation having as input the average ratio, a wheel base measurement, a vehicle track width, and a hitch point to rear axle center-line distance.

16. The method of claim 13, wherein the step of calculating the trailer length additionally comprises fitting the average ratio to a predictive model and setting the trailer length to a trailer length value that is assigned to a ratio value matching the average ratio.

17. The method of claim 13, wherein the look up table comprises a first set of ratio values, a second set of ratio values, and an associated trailer length value assigned to each ratio value in the first and second sets of ratio values.

18. The method of claim 17, wherein the first set of ratio values correspond to ratio values determined using a first computation and the second set of ratio values correspond to ratio values determined using a second computation.

19. The method of claim 13, wherein the wheel steer angle and the hitch angle are determined when an axle center-line of a trailer is aligned with a center of rotation of a vehicle towing the trailer.