JACKKNIFE DETECTION FOR VEHICLE REVERSING A TRAILER

• US 20170008560A1
• Filed: 07/08/2015
• Published: 01/12/2017
• Est. Priority Date: 07/08/2015
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Kyrtsos, Christos, Lavoie, Erick Michael
• Granted Patent: US 9,896,126 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2556/00 Input parameters relating to data
• CPC Class Codes: B60W 2710/18 Braking system
• CPC Class Codes: B60W 2710/20 Steering systems
• CPC Class Codes: B60W 30/06 Automatic manoeuvring for parking
• CPC Class Codes: B62D 13/06 for backing a normally drawn trailer
• CPC Class Codes: B62D 15/021 Determination of steering angle

Abstract

A backup assist system for a vehicle reversing a trailer includes a hitch angle sensor providing a measured hitch angle of the trailer. The system also includes a controller determining a position of the measured hitch angle in relation to an unknown jackknife angle by monitoring a predetermined dynamic hitch angle characteristic derived from the measured hitch angle for a corresponding jackknife indicating characteristic.

Claims

1. A backup assist system for a vehicle reversing a trailer, comprising:

a hitch angle sensor providing a measured hitch angle of the trailer; and

a controller determining a position of the measured hitch angle in relation to an unknown jackknife angle by monitoring a predetermined dynamic hitch angle characteristic derived from the measured hitch angle for a corresponding jackknife indicating characteristic.

2. The backup assist system of claim 1, wherein the predetermined dynamic hitch angle characteristic is a rate of change of the measured hitch angle.

3. The backup assist system of claim 2, wherein the jackknife indicating characteristic is the rate of change of the measured hitch angle approaching a peak value.

4. The backup assist system of claim 2, wherein the jackknife indicating characteristic is a derivative of the rate of change of the measured hitch angle approaching zero.

5. The backup assist system of claim 4, further including:

estimating the jackknife angle based on the measured hitch angle when derivative of the rate of change of the measured hitch angle is within a predetermined range of zero; and

estimating a distance between a hitch of the vehicle and a front axle of the trailer using the estimated jackknife angle in a kinematic model.

6. The backup assist system of claim 2, wherein the rate of change of the measured hitch angle is calculated using the equation:

7. The backup assist system of claim 1, further including a brake control system, wherein:

the controller an alternate brake pulse scheme to the brake control system; and

the predetermined hitch angle characteristic is an aggregate direction of a trailer wiggle induced by the alternate brake pulse scheme.

8. The backup assist system of claim 7, wherein the jackknife indicating characteristic is a series of oscillations of the trailer wiggle exhibiting a magnitude in a direction away from the vehicle below a predetermined threshold.

9. The backup assist system of claim 7, wherein the jackknife indicating characteristic includes an aggregate trailer wiggle direction being disposed toward the vehicle.

10. The backup assist system of claim 9, further including identifying the unknown jackknife angle at a measured hitch angle at which the series of oscillations of the trailer wiggle are successively toward the vehicle.

11. A vehicle, comprising:

a steering system;

a hitch angle detector; and

a control system coupled with the steering system and implementing a backup mode for reversing a trailer including controlling the steering system to maintain the trailer along a path and further coupled with the hitch angle detector for determining a relationship between a measured hitch angle and an unknown jackknife angle by monitoring a predetermined dynamic hitch angle characteristic for a jackknife indicator.

12. The vehicle of claim 11, wherein the predetermined dynamic hitch angle characteristic is a rate of change of the measured hitch angle.

13. The vehicle of claim 12, wherein the jackknife indicator is a derivative of the rate of change of the measured hitch angle approaching zero.

14. The vehicle of claim 11, further including a brake system, wherein:

the control system is further coupled with the brake system to implement an alternate brake pulse scheme; and

the predetermined hitch angle characteristic is an instantaneous direction of a trailer wiggle induced by the alternate brake pulse scheme.

15. The vehicle of claim 14, wherein the jackknife indicator is a series of oscillations of the trailer wiggle converging toward the vehicle.

16. A method for assisting reversing of a vehicle with a trailer, comprising:

controlling a steering angle of a vehicle steering system to maintain the trailer along a user-selected reversing curvature path;

continuously measuring a hitch angle of the trailer relative to the vehicle;

monitoring a predetermined dynamic hitch angle characteristic for a jackknife indicator; and

determining a relationship between the measured hitch angle and an unknown jackknife angle based on the dynamic hitch angle characteristic.

17. The method of claim 16, further comprising:

altering the user-selected reversing curvature path based on a determination that the measured hitch angle is approaching the unknown jackknife angle.

18. The method of claim 16, further comprising implementing an alternate brake pulse scheme in a brake system of the vehicle, wherein:

the predetermined dynamic hitch angle characteristic is a trailer wiggle induced by the alternate brake pulse scheme; and

the jackknife indicator is a series of oscillations of the trailer wiggle having a magnitude in a direction away from the vehicle below a predetermined threshold.

19. The method of claim 18, further comprising adjusting the predetermined threshold based on at least one of a vehicle velocity and a trailer length.

20. The method of claim 16, wherein:

the predetermined dynamic hitch angle characteristic is a rate of change of the measured hitch angle; and

the jackknife indicator is a derivative of the rate of change of the measured hitch angle approaching zero.