Path planner and method for planning a contour path of a vehicle

• US 7,216,033 B2
• Filed: 01/25/2005
• Issued: 05/08/2007
• Est. Priority Date: 03/31/2003
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Hansen, Shane Lynn, Gray, Sarah Ann, Flann, Nicholas Simon
• Primary Examiner(s): Tran; Dalena
• Application Number:
  US11/042,671
• Publication Number:
  US 20050197766A1
• Time in Patent Office: 833 Days
• Field of Search: 701/202, 701/23, 701/25, 701/26, 701/50, 701/209, 56/102.A, 172/2, 340/995.19
• US Class Current: 701/202
• CPC Class Codes: A01B 69/008 automatic
• CPC Class Codes: A01B 79/005 Precision agriculture
• CPC Class Codes: G05D 1/0219 ensuring the processing of the whole working surface
• CPC Class Codes: G05D 2201/0201 Agriculture or harvesting machine

Abstract

In accordance with one embodiment of the invention, a path planner and method for planning a path of a vehicle defines a reference row having a reference contour in a work area. A representation of the defined reference row is established. The defined reference row comprises a curved component, a generally linear component, or both. A generator generates one or more contour rows with a tracking contour that tracks or mirrors the reference contour based on a vehicular width and a radius difference parameter associated with the curved component. The contour rows are generated by a translation technique for the generally linear component and a radius modification technique for the curved component.

Claims

1. A method for planning a path of a vehicle, the method comprising:

defining a reference row having a reference contour in a work area;

establishing a representation of the defined reference row, the reference row comprising at least one of a generally curved component and a generally linear component; and

generating one or more contour rows with a tracking contour that tracks or mirrors the reference contour based on a vehicular width and a radius difference parameter associated with the curved component;

the contour rows generated by a translation technique for the generally linear component and a radius modification technique for the curved component;

where the generating comprises applying a search algorithm to possible candidate values of the radius difference parameter, and where the search space is limited such that the radius difference parameter is bounded by a candidate radius difference parameter generally equal to or less than the vehicular width.

2. The method according to claim 1 wherein the representation of the curved component comprises an arc segment and wherein the linear component comprises a linear segment.

3. The method according to claim 2 wherein the establishing of the representation comprises defining the arc segment as a center point, a start point, an end point and a radius, where the arc segment has a radius greater than the minimum turning radius of the vehicle;

wherein the establishing of the representation comprises defining the linear segment as two points.

4. The method according to claim 1 wherein the representation comprises one or more corners defined by location data and a sequence for traversing the corners.

5. The method according to claim 1 wherein the representation comprises one or more critical points of material directional change of the vehicle, each critical point defined by a pair of location data and a corresponding heading, each pair assigned a sequence for traversing the critical points.

6. The method according to claim 1 wherein the defining further comprises defining the reference row having a reference contour that follows along a boundary contour of a boundary of the work area.

7. The method according to claim 1 wherein if the radius difference parameter generally equals the vehicular width, a nesting solution applies to adjacent rows on a local basis.

8. The method according to claim 1 further comprising:

identifying the presence of two adjacent outside arcs separated by a linear segment in an outer contour row located toward an outer boundary of the work area; and

determining a single outside arc for an inner contour row that tracks the outer contour row, the inner contour row located closer to an interior of the work area than the outer contour row.

9. The method according to claim 1 further comprising:

identifying a presence of an inside arc and outside arc being adjacent to each other, in a proposed contour row where such inside arc and outside arc would cross over each other; and

applying an iterative repair process to reformulate the proposed contour row.

10. The method according to claim 1 wherein generating comprises applying a search algorithm to possible candidate values of the radius difference parameter, wherein the search space is limited such that search is star-ted with the radius difference parameter equal to the vehicular width and the radius difference parameter is decreased therefrom.

11. The method according to claim 1 further comprising:

determining a first figure of merit for a corresponding linear coverage path for covering a work area, the first figure of merit indicating at least one of a total energy consumption, a total distance, or a total time duration of the vehicle for completing the linear coverage path;

determining a second figure of merit for a corresponding contour coverage path for covering the work area, at least one of a total energy consumption, a total distance, or a total time duration of the vehicle for completing the contour coverage path;

selecting the contour coverage path if the second figure of merit is superior to the first figure of merit.

12. The method according to claim 11 wherein the determining of the first figure of merit further comprises:

estimating a total length in distance for the vehicle to execute a linear coverage path for the work area; and

estimating the number or corresponding length of turns at the end of rows for the linear coverage path.

13. The method according to claim 12 wherein the determining of the second figure of merit further comprises:

estimating a total length in distance for the vehicle to execute a contour coverage path for the work area; and

estimating the number or corresponding length of turns at the end of rows for the contour coverage path.

14. A path planner for planning a path of a vehicle, the path planner comprising:

a definer for defining a reference row having a reference contour in a work area;

a representation former for establishing a representation of the defined reference row, the representation comprising an arc segment and at least one of a linear segment and a transition; and

a generator for generating one or more contour rows with a tracking contour that tracks or mirrors the reference contour based on a vehicular width and a radius difference parameter associated with the arc segment;

the contour rows generated by at least one of a translation technique, a radius modification technique, and a hybrid technique;

where the generator further comprises a search engine for applying a search algorithm possible candidate values of the radius difference parameter and wherein search space is limited such that the radius difference parameter is bounded by a candidate radius difference parameter generally equal to or less than the vehicular width.

15. The path planner according to claim 14 wherein the definer defines the reference row having a reference contour that follows along a boundary contour of a boundary of the work area.

16. The path planner according to claim 15 wherein the reference row is contiguous with the boundary.

17. The path planner according to claim 14 wherein the definer defines a reference row that does not track a boundary of the work area.

18. The path planner according to claim 14 wherein the representation former defines the arc segment as a center point, a start point, an end point and a radius, where any arc segment has a radius greater than the minimum turning radius of the vehicle.

19. The path planner according to claim 14 wherein the representation former defines the linear segment as two point.

20. The path planner according to claim 14 wherein the generator further comprises a radius modifier for selecting the radius difference parameter such that if the radius difference parameter generally equals the vehicular width, a nesting solution applies to adjacent rows on a local basis.

21. The path planner according to claim 14 further comprising:

an interference module for identifying the presence of two adjacent outside arcs separated by a linear segment in an outer contour row located toward an outer boundary of the work area; and

the interference module determining a single outside arc for an inner contour row that tracks the outer contour row, the inner contour row located closer to an interior of the work area than the outer contour row.

22. The path planner according to claim 14 further comprising:

an interference module for identifying a presence of an inside arc and outside arc being adjacent to each other, in a contour row where such inside arc and outside arc would cross over each other; and

the interference module applying an iterative repair process to reformulate the contour row.

23. The path planner according to claim 14 wherein generator further comprises a search engine for applying a search algorithm to possible candidate values of the radius difference parameter, wherein the search space is limited such that search is started with the radius difference parameter equal to the vehicular width and the radius difference parameter is decreased therefrom.

24. The path planner according to claim 14 further comprising:

a linear path estimator for estimating a linear path estimate of at least one of a total length, a total time and a total energy consumption for a vehicle to execute a generally linear path plan;

a contour path estimator for estimating a contour path estimate of at least one of a total length, a total time, and a total energy consumption for a vehicle to execute a generally contour path plan;

a turn estimator for estimating turn estimates of at least one of a length, time duration and energy consumption associated with the turns at end of rows of the generally linear path plan and the contour path plan;

a data processor for determining a first figure of merit for the corresponding linear path and for determining a second figure of merit for the corresponding contour path plan based on the linear path estimate, the contour path estimate, and the turn estimates;

the data processor adapted to select the contour coverage path if the second figure of merit is superior to the first figure of merit.