System and method for calculating instantaneous placement corrections to achieve towed implement placement on curved paths

• US 20080004778A1
• Filed: 06/30/2006
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Rekow, Andrew Karl Wilhelm
• Granted Patent: US 7,509,199 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: A01B 69/004 automatic
• CPC Class Codes: E02F 9/2045 Guiding machines along a predetermined path for graders E02F3/841; machines for construction of roads E01C19/004
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS

Abstract

A global positioning system (GPS) based navigation and steering control system for ground vehicles, in particular, agricultural ground vehicles such as tractors, combines, sprayers, seeders, or the like, calculates instantaneous placement corrections to achieve desired towed implement placement on curved paths, and a method for same.

Claims

1. A method for controlling the steering of a ground vehicle towing an implement to achieve a desired placement of the towed implement on a curved path, comprising:

determining instantaneous placement corrections from a predetermined track along the curved path for the ground vehicle for achieving a desired towed implement trajectory along the curved path;

calculating an instantaneous ground vehicle offset from the predetermined track using the instantaneous placement corrections; and

correcting the trajectory of the ground vehicle using the instantaneous ground vehicle offset for adjusting the path of the ground vehicle so that the towed implement at least substantially follows the curved path.

2. The method as claimed in claim 1, wherein the step of determining the instantaneous placement corrections further comprises determining a steady state implement angle for the towed implement.

3. The method as claimed in claim 2, wherein the step of determining the instantaneous placement corrections comprises determining an initial ground vehicle turning radius.

4. The method as claimed in claim 3, wherein the step of determining the instantaneous placement corrections comprises determining a steady state implement drift offset and a steady state turn radius for the towed implement.

5. The method as claimed in claim 4, further comprising determining if the trajectory of the ground vehicle has changed.

6. The method as claimed in claim 4, wherein the initial ground vehicle turning radius is determined from

R_ground—

_vehicle=R_segment+[b_i(a_i+b_i)+½

(a_i+b_i)²]

where R<sub>ground—

vehicle</sub> is the initial ground vehicle turning radius, R_segment is the desired implement turning radius, a_i is a distance from the center of the ground vehicle rear axle to the drawbar pin and b_i is the distance from the drawbar pin to the turning center of the implement.

7. The method as claimed in claim 6, wherein the steady state implement angle for the towed implement is determined from

8. The method as claimed in claim 6, wherein the steady state implement angle is determined by

determining an initial estimate of the steady state implement angle;

calculating an angle residual for the steady state implement angle; and

revising the estimate of the steady state implement angle using the calculated angle residual.

9. The method as claimed in claim 8, wherein the initial estimate of the steady state implement angle is determined from

10. The method as claimed in claim 9, wherein the steady state ground vehicle offset is determined from

11. The method as claimed in claim 10, wherein the instantaneous ground vehicle offset is determined from

12. The method as claimed in claim 10, wherein an instantaneous placement correction is determined from

13. A system for controlling the steering of a ground vehicle towing an implement to achieve a desired placement of the towed implement on a curved path, comprising:

a processing system for determining the instantaneous placement corrections from a predetermined track along the curved path for the ground vehicle for achieving a desired towed implement trajectory along the curved path and calculating an instantaneous ground vehicle offset from the predetermined track using the steady state ground vehicle offset; and

a steering control unit for correcting the trajectory of the ground vehicle using the instantaneous placement corrections,

wherein the steering control unit adjusts the path of the ground vehicle so that the towed implement at least substantially follows the curved path.

14. The system as claimed in claim 13, wherein the processing system determines a steady state implement angle for the towed implement.

15. The system as claimed in claim 14, wherein the processing system determines an initial ground vehicle turning radius.

16. The system as claimed in claim 15, wherein the processing system determines a steady state implement drift offset and a steady state turn radius for the towed implement.

17. The system as claimed in claim 16, wherein the processing system further determines if the trajectory of the ground vehicle has changed.

18. The system as claimed in claim 17, wherein the steady state implement angle is determined by the processing system by

determining an initial estimate of the steady state implement angle;

calculating an angle residual for the steady state implement angle; and

revising the estimate of the steady state implement angle using the calculated angle residual.

19. A system for controlling the steering of a ground vehicle towing an implement to achieve a desired placement of the towed implement on a curved path, comprising:

means for determining instantaneous placement corrections from a predetermined track along the curved path for the ground vehicle for achieving a desired towed implement trajectory along the curved path and calculating an instantaneous ground vehicle offset from the predetermined track using the steady state ground vehicle offset; and

means for correcting the trajectory of the ground vehicle using the instantaneous placement corrections,

wherein the correcting unit adjusts the path of the ground vehicle so that the towed implement at least substantially follows the curved path.

20. The system as claimed in claim 19, further comprising means for determining if the trajectory of the ground vehicle has changed.