TRAILER BACKUP OFFSET DETERMINATION

• US 20160039456A1
• Filed: 10/19/2015
• Published: 02/11/2016
• 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, Raad, Joseph M., Mattern, Donald Jacob
• Granted Patent: US 9,937,953 B2
• Time in Patent Office: 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: B60Q 9/005 using a video camera
• CPC Class Codes: B60W 2050/0088 Adaptive recalibration
• CPC Class Codes: B60W 2520/22 Articulation angle, e.g. between tractor and trailer
• CPC Class Codes: B60W 50/0098 Details of control systems ensuring comfort, safety or stability not otherwise provided for
• CPC Class Codes: B62D 13/06 for backing a normally drawn trailer
• CPC Class Codes: B62D 15/027 Parking aids, e.g. instruction means

Abstract

A system for calibrating a backup assist system for a trailer attached to a vehicle is provided which includes a hitch sensor continuously measuring a hitch angle for determining an angle rate, a yaw sensor continuously sensing a yaw rate of the vehicle, and a controller configured to determine an offset of the measured hitch angle when vehicle is driving forward and/or rearward.

Claims

1. A system for calibrating a backup assist system for a trailer attached to a vehicle, comprising:

a hitch angle sensor continuously measuring a hitch angle for determining a hitch angle rate;

a yaw sensor continuously sensing a yaw rate of the vehicle; and

a controller configured to determine an offset of the measured hitch angle when the vehicle is driving forward and rearward above a threshold speed and the hitch angle rate is substantially zero.

2. The system of claim 1, wherein the offset is determined between the measured hitch angle and an actual hitch angle when the actual hitch angle is substantially zero.

3. The system of claim 1, wherein the controller determines the angle rate based on changes in the measured hitch angle over time, and wherein the hitch sensor includes a video imaging camera on the vehicle that continuously monitors a target on the trailer.

4. The system of claim 1, wherein the controller determines the offset while the vehicle is moving rearward when a steering angle rate is substantially zero.

5. The system of claim 1, wherein the controller determines the offset while the vehicle is moving forward when the yaw rate of the vehicle is substantially constant.

6. The system of claim 1, wherein the controller is configured to prioritize the offset determined while the vehicle and the trailer are moving reverse over the offset determined while the vehicle and the trailer are moving forward.

7. The system of claim 6, wherein the controller is configured to replace a forward offset when a reverse offset is determined.

8. A method of calibrating a backup assist system for a trailer and a vehicle, comprising:

driving the vehicle forward to determine a forward offset between measured and actual hitch angles;

storing the forward offset in memory;

driving the vehicle in reverse to determine a reverse offset between the measured hitch angle and the actual hitch angle;

replacing the forward offset in memory with the reverse offset; and

calibrating the system using the reverse offset.

9. The method of claim 8, wherein the reverse offset may not be replaced with the forward offset.

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

11. The method of claim 8, further comprising:

sensing angular changes of the vehicle with an inertial sensor on the vehicle, wherein the forward offset and the reverse offset are determined when the angular changes are substantially zero.

12. The method of claim 8, further comprising:

sensing a yaw rate of the vehicle with a yaw sensor on the vehicle, wherein the forward offset is determined when the yaw rate is substantially constant and a hitch angle rate are substantially zero over a threshold time while the vehicle is driving forward above the threshold speed.

13. The method of claim 8, wherein the forward offset and the reverse offset are determined during a steady state condition of the vehicle and the trailer.

14. The method of claim 8, further comprising:

determining an approximate distance the vehicle needs to travel forward or in reverse in a substantially straight orientation to place the actual hitch angle at zero, wherein the approximate distance is determined based on a length of the trailer and the measured hitch angle.

15. A system for calibrating a backup assist system for a trailer attached to a vehicle, comprising:

a hitch sensor continuously measuring a hitch angle between the vehicle and the trailer; and

a controller configured to determine an offset of the measured hitch angle, wherein the controller is configured to calculate and store in memory a forward offset if no reverse offset is stored.

16. The system of claim 15, wherein the controller is further configured to not calculate a forward offset if the reverse offset is stored.

17. The system of claim 15, wherein the forward and reverse offsets are determined during a steady state condition of the vehicle and the trailer.

18. The system of claim 15, further comprising:

a knob sensor continuously sensing a knob angle, wherein the knob angle is substantially zero when the vehicle and trailer are in a substantially standing state, and wherein the reverse offset is determined when the knob angle is substantially zero over a threshold time while the vehicle is driving above a threshold speed.

19. The system of claim 16 further comprising:

a yaw sensor continuously sensing a yaw rate of the vehicle, wherein the yaw rate of the vehicle is substantially zero when the vehicle is steered straight, and wherein the forward and reverse offsets are determined when the angle rate is substantially zero over a threshold time while the vehicle is driving above a threshold speed.

20. The system of claim 16, wherein the controller determines an approximate distance the vehicle must travel straight to place the actual hitch angle at zero based on a length of the trailer and the measured hitch angle.