Estimating a trailer road grade

• US 9,744,970 B2
• Filed: 07/14/2014
• Issued: 08/29/2017
• Est. Priority Date: 07/14/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Yu, Hai
• Primary Examiner(s): CAMBY, RICHARD M
• Application Number:
  US14/330,622
• Publication Number:
  US 20160009288A1
• Time in Patent Office: 1,142 Days
• Field of Search: 701 41- 43
• CPC Class Codes: B60T 2230/08 Driving in reverse
• CPC Class Codes: B60T 2250/02 Vehicle mass
• CPC Class Codes: B60T 7/20 specially for trailers, e.g. in case of uncoupling of or overrunning by trailer inertia-actuated overrun brakes B60T13/08
• CPC Class Codes: B60T 8/1708 for lorries or tractor-trailer combinations
• CPC Class Codes: B60W 40/076 Slope angle of the road
• CPC Class Codes: B60W 40/13 Load or weight
• CPC Class Codes: B60W 50/14 Means for informing the driver, warning the driver or prompting a driver intervention
• CPC Class Codes: B62D 13/06 for backing a normally drawn trailer

Abstract

An example trailer road grade estimating method includes calculating a road grade beneath a trailer vehicle based on a difference between a first estimated mass and a second estimated mass.

Claims

1. A trailer road grade estimating method, comprising:

altering operation of a towing vehicle in response to a road grade beneath a trailer vehicle, the road grade calculated by a controller and being based on a difference between a first estimate of a mass and a second estimate of the mass.

2. The method of claim 1, further comprising calculating the first estimate when the trailer vehicle is at a first position and calculating the second estimate when the trailer vehicle is at a second position different than the first position.

3. The method of claim 2, wherein the method comprises pushing the trailer vehicle with the towing vehicle to move the trailer vehicle from the first position to the second position.

4. The method of claim 1, wherein the first estimate comprises an estimate of a total mass of the towing vehicle and a total mass of the trailer vehicle.

5. The method of claim 2, further comprising running an automatic backup assist for the towing vehicle coupled with the trailer vehicle during the calculating.

7. The method of claim 1, wherein the calculating comprises deriving the road grade according to a formula where the road grade is α

sin

8. The method of claim 1, further comprising braking the towing vehicle, the trailer vehicle, or both in response to an increase in the road grade.

9. The method of claim 8, wherein the braking comprises friction braking.

10. The method of claim 1, further comprising sending a warning to an operator of the towing vehicle if the road grade exceeds a threshold value.

11. The method of claim 1, further comprising pausing an automatic backup operation if the road grade exceeds a threshold value.

12. The method of claim 9, further comprising calculating a total road grade load torque on the towing vehicle based on the difference.

13. The method of claim 12, wherein the total road grade load torque is calculated according to a formula wherein the total road grade load torque is:

(M_c−

m*_trk)g sin α

_r2+m*_trkg sin α

_r1.

21. The method of claim 13, wherein M_c represents a total unit mass of the towing vehicle added to a total mass of the trailer vehicle, m*_trk represents an estimated mass of the towing vehicle, α

_r1 represents a road grade under the towing vehicle, g represents gravity, and α

_r2 represents a road grade under the trailer vehicle.

6. A trailer road grade estimating method, comprising:

altering operation of a towing vehicle in response to a road grade beneath a trailer vehicle, the road grade calculated by a controller and being based on a difference between a first estimate of a mass and a second estimate of the mass,

wherein a variation between a grade beneath the towing vehicle and a grade beneath the trailer vehicle causes the difference between the first estimate of the mass and the second estimate of the mass.

14. A vehicle control assembly, comprising:

a vehicle controller that estimates a road grade for a trailer vehicle based on a difference between a first estimate of a mass and a second estimate of the mass and provides an input that alters operation of a towing vehicle in response to the road grade.

15. The assembly of claim 14, wherein the first estimate of a mass is calculated when the trailer vehicle is at a first position and the second estimate of a mass is calculated when the trailer vehicle is at a second position different than the first position.

16. The assembly of claim 15, wherein the trailer vehicle is moved in reverse from the first position to the second position.

17. The assembly of claim 14, wherein the vehicle controller estimates the road grade using a formula where the road grade is α

sin

18. The assembly of claim 14, including a friction brake, the vehicle controller to increase braking force from the friction brake in response to an increase in the road grade.

20. The assembly of claim 14, wherein the towing vehicle houses the vehicle controller.

22. The assembly of claim 17, wherein {hacek over (M)}_c represents an estimated mass for the towing vehicle and the trailer vehicle, M_c represents the total unit mass of the towing vehicle added to the total mass of the trailer vehicle, a_x^s represents an acceleration output from an accelerometer, m*_trk represents an estimated mass of the towing vehicle, g represents gravity, and α

_r1 represents a road grade under the towing vehicle.

19. A vehicle control assembly, comprising:

a vehicle controller that estimates a road grade for a trailer vehicle based on a difference between a first estimate of a mass and a second estimate of the mass and provides an input that alters operation of a towing vehicle in response to the road grade,

wherein the vehicle controller executes a program causing a towing vehicle to automatically back up the trailer vehicle.