Trailer backup assist system with trajectory planner for multiple waypoints

• US 9,238,483 B2
• Filed: 04/21/2014
• Issued: 01/19/2016
• 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: Hafner, Michael, Pilutti, Thomas Edward
• Primary Examiner(s): Black, Thomas G
• Assistant Examiner(s): Kong, Sze-Hon
• Application Number:
  US14/257,384
• Publication Number:
  US 20140303849A1
• Time in Patent Office: 638 Days
• Field of Search: 701/42
• 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 10/04 including control of propulsion units
• 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 2050/146 Display means
• CPC Class Codes: B60W 2300/14 Tractor-trailers, i.e. combinations of a towing vehicle and one or more towed vehicles, e.g. caravans; Road trains
• 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 30/00 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: B60W 30/045 Improving turning performance
• CPC Class Codes: B60W 30/06 Automatic manoeuvring for parking
• CPC Class Codes: B60W 30/18036 Reversing
• 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
• CPC Class Codes: B62D 15/027 Parking aids, e.g. instruction means
• CPC Class Codes: H04N 7/183 for receiving images from a single remote source

Abstract

A trailer backup assist system, according to one embodiment, includes a state estimator that determines a current position of a trailer relative to a plurality of waypoints. A trajectory planner may then incrementally generate a path from the current position to the plurality of waypoints. The trajectory planner has a first mode that generates first and second circular trajectories tangent to one another connecting between the current position and a waypoint of the plurality of waypoints. A second mode of the trajectory planner generates the second circular trajectory between the current position and the waypoint after the trailer traverses the first circular trajectory. Also, a third mode of the trajectory planner switches to the first operating mode when the trailer reaches the waypoint for guidance to a subsequent waypoint. A curvature controller guides the trailer based on a curvature of the respective first or second circular trajectories.

Claims

1. A trailer backup assist system comprising:

a state estimator determining a current position of a trailer relative to a plurality of waypoints;

a trajectory planner for incrementally generating a path from the current position to the plurality of waypoints, comprising;

a first mode generating first and second circular trajectories tangent to one another connecting between the current position and a waypoint of the plurality of waypoints;

a second mode generating the second circular trajectory between the current position and the waypoint after the trailer traverses the first circular trajectory; and

a third mode switching to the first operating mode when the trailer reaches the waypoint for guidance to a subsequent waypoint of the plurality of waypoints; and

a curvature controller guiding the trailer based on a curvature of the respective first or second circular trajectories.

2. The trailer backup assist system of claim 1, wherein the first mode dynamically regenerates the first and second circular trajectories as the trailer reverses on the first circular trajectory.

3. The trailer backup assist system of claim 1, wherein the plurality of waypoints each include a coordinate location and an angular orientation, and wherein the second mode generates the second circular trajectory independent of the angular orientation at the waypoint.

4. The trailer backup assist system of claim 1, wherein the first mode stops and the second mode begins to generate the second circular trajectory when the trailer reaches a position tangent to both the first and second circular trajectories.

5. The trailer backup assist system of claim 1, wherein the curvature controller generates a steering angle command for a vehicle towing the trailer as a function of a hitch angle between the vehicle and the trailer, a steering angle of the vehicle, and the curvature of the respective first or second circular trajectory that the trailer is on.

6. The trailer backup assist system of claim 1, wherein the plurality of waypoints includes a final waypoint, whereby the trajectory planner includes a fourth mode for stopping the trailer when the trailer reaches the final waypoint.

7. The trailer backup assist system of claim 6, wherein the path between the plurality of waypoints is configured to avoid an obstacle between an initial waypoint and the final waypoint.

8. The trailer backup assist system of claim 7, wherein the state estimator includes a positioning device that generates a localized coordinate system that encompasses the plurality of waypoints.

9. A trailer backup assist system, comprising:

a trajectory planner comprising;

a first mode generating first and second of circular trajectories tangent to one another connecting between a current position of a trailer and a waypoint of a plurality of waypoints;

a second mode generating the second circular trajectory to the waypoint; and

a third mode switching to the first operating mode at the waypoint if the plurality of waypoints includes a subsequent waypoint; and

a controller guiding the trailer based on the first and second circular trajectories.

10. The trailer backup assist system of claim 9, wherein the first mode dynamically regenerates the first and second circular trajectories as the trailer reverses on the first circular trajectory.

11. The trailer backup assist system of claim 9, wherein the trajectory planner further comprises:

a fourth mode stopping the trailer when the trailer reaches a final waypoint of the plurality of waypoints.

12. The trailer backup assist system of claim 9, wherein the plurality of waypoints each include a coordinate location and an angular orientation.

13. The trailer backup assist system of claim 12, wherein the second mode generates the second circular trajectory once the trailer traverses the first circular trajectory and independent of the angular orientation at the waypoint.

14. The trailer backup assist system of claim 9, wherein the second mode begins to generate the second circular trajectory when the trailer reaches a position tangent to both the first and second circular trajectories.

15. The trailer backup assist system of claim 9, wherein the controller comprises a curvature controller that guides the trailer based on a curvature of the first circular trajectory in the first mode and of the second circular trajectory in the second mode.

16. The trailer backup assist system of claim 15, wherein the curvature controller generates a steering angle command for a vehicle towing the trailer as a function of a hitch angle between the vehicle and the trailer, a steering angle of the vehicle, and the curvature.

17. A method for reversing a trailer between a plurality of waypoints, comprising:

generating with a processor first and second circular trajectories tangent to one another connecting between a current position of the trailer and a first waypoint of the plurality of waypoints;

guiding with a controller the trailer along the first circular trajectory while regenerating the first and second circular trajectories;

guiding with the controller the trailer along the second circular trajectory to the first waypoint while regenerating the second circular trajectory;

generating with the processor third and fourth circular trajectories tangent to one another connecting between the current position and a second waypoint of the plurality of waypoints;

guiding with the controller the trailer along the third circular trajectory while regenerating the third and fourth circular trajectories; and

guiding with the controller the trailer along the fourth circular trajectory to the second waypoint.

18. The method of claim 17, further comprising:

determining the current position of the trailer relative to the plurality of waypoints.

19. The method of claim 17, wherein the plurality of waypoints each include a coordinate location and an angular orientation, and wherein the second circular trajectory is dynamically regenerated independent of the angular orientation of the first waypoint.

20. The method of claim 17, further comprising:

switching from guiding the trailer along the first circular trajectory to guiding the trailer along the second circular trajectory when the trailer reaches a tangent position between the first and second circular trajectories.