System and method for area coverage using sector decomposition

• US 8,989,946 B2
• Filed: 03/05/2012
• Issued: 03/24/2015
• Est. Priority Date: 12/17/2009
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Anderson, Noel Wayne
• Primary Examiner(s): Amin, Bhavesh V
• Application Number:
  US13/411,999
• Publication Number:
  US 20120166019A1
• Time in Patent Office: 1,114 Days
• Field of Search: 701/1, 701/23, 701/25, 701/26, 701/28, 701/400, 701/408, 701/409, 701/410, 701/411
• US Class Current: 701/25
• CPC Class Codes: G05D 1/0219 ensuring the processing of the whole working surface
• CPC Class Codes: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means
• CPC Class Codes: G05D 1/0251 extracting 3D information from a plurality of images taken from different locations, e.g. stereo vision stereoscopic image analysis H04N13/00; depth recovery from images G06T7/593
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93
• CPC Class Codes: G05D 1/0259 using magnetic or electromagnetic means
• CPC Class Codes: G05D 1/0265 using buried wires
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30
• CPC Class Codes: G06V 20/10 Terrestrial scenes scenes under surveillance with static cameras G06V20/52; scenes perceived from the exterior of a vehicle G06V20/56; scenes perceived from the interior of a vehicle G06V20/59

Abstract

The different illustrative embodiments provide a method for generating an area coverage path plan using sector decomposition. A starting point is identified on a worksite map having a number of landmarks. A first landmark in the number of landmarks is identified. A path is generated around the first landmark until an obstacle is detected. In response to detecting the obstacle, the path is made linear to a next landmark. The path is generated around the next landmark.

Claims

1. A method for generating and executing an area coverage path plan, the method comprising:

identifying, via a processor of an autonomous vehicle, a starting point on a worksite map having a number of landmarks;

identifying, via the processor, a first landmark in the number of landmarks;

generating, via the processor, a path around the first landmark until an obstacle is detected, wherein the path around the first landmark is a set of concentric arcs;

responsive to detecting the obstacle by the autonomous vehicle, the processor making the path linear to a vicinity of a next landmark;

generating, via the processor, the path around the next landmark, wherein the path around the next landmark is another set of concentric arcs; and

sending control signals to a mobility system of the autonomous vehicle to move the autonomous vehicle according to the generated path to thereby execute the area coverage path plan by the autonomous vehicle.

2. The method of claim 1, wherein the path around the first landmark is a set of concentric arcs.

3. The method of claim 1, wherein generating the path around the first landmark further comprises:

determining whether a first worksite boundary is detected;

responsive to a determination that the first worksite boundary is detected, moving the path a predefined width away from the first landmark along the first worksite boundary; and

continuing the path around the first landmark.

4. The method of claim 3, further comprising:

responsive to a determination that the first worksite boundary is not detected, determining whether an obstacle is detected; and

responsive to a determination that no obstacle is detected, continuing the path around the first landmark.

5. The method of claim 4, further comprising:

iteratively generating the path around the number of landmarks until the path covers the worksite map; and

generating a path plan using the path covering the worksite map.

6. An apparatus for generating an area coverage path plan, the apparatus comprising:

a processor unit configured to generate an area coverage path plan for a worksite using a number of landmarks and a sector decomposition process that generates paths which follow arcs at predefined distances from the number of landmarks; and

a vehicle control process configured to execute the area coverage path plan for the worksite received from the processor unit using a mobility system, wherein the processor unit is further configured to receive a worksite map for the worksite having the number of landmarks;

generate an area coverage grid map having a number of area coverage grid elements for the worksite using the worksite map;

generate a path plan for the worksite using the worksite map and the area coverage grid map;

mark the number of landmarks on the worksite map as unvisited; and

initialize the number of area coverage grid elements as uncovered.

7. The apparatus of claim 6, wherein the mobility system is further configured to perform an area coverage task at the worksite.

8. The apparatus of claim 6, wherein the worksite map includes at least one of a number of landmark locations, a number of landmark attributes, and a number of obstacles.

9. The apparatus of claim 6, wherein the processor unit is further configured to identify a landmark marked as unvisited on the worksite map;

and send a message to the vehicle control process to proceed to a vicinity of the landmark marked as unvisited.

10. The apparatus of claim 6, wherein the processor unit is further configured to

determine whether an obstacle is detected;

responsive to a determination that the obstacle is detected, mark the landmark marked as unvisited as visited on the worksite map; and

mark associated area coverage grid elements of the landmark marked as visited as covered.

11. The apparatus of claim 6, wherein the processor unit is further configured to determine whether there are any remaining landmarks marked as unvisited;

responsive to a determination that there are remaining landmarks marked as unvisited, identify a next landmark marked as unvisited on the worksite map; and

send a message to the vehicle control process to proceed to a vicinity of the next landmark marked as unvisited.

12. The apparatus of claim 6, wherein the processor unit is further configured to, responsive to a determination that there are no remaining landmarks marked as unvisited, determine whether there are any remaining area coverage grid elements marked as uncovered;

responsive to a determination that there are remaining area coverage grid elements marked as uncovered, send a message to the vehicle control process to proceed along the path plan to a visited landmark associated with an area coverage grid element marked as uncovered; and

execute an area coverage behavior on a path around the visited landmark.

13. The apparatus of claim 6, further comprising:

a vision system configured to capture a number of images of the worksite.