METHOD OF ACCURATE MAPPING WITH MOBILE ROBOTS

• US 20130060382A1
• Filed: 11/01/2012
• Published: 03/07/2013
• Est. Priority Date: 04/24/2009
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Pitzer, Benjamin
• Granted Patent: US 8,831,778 B2
• Time in Patent Office: Days
• US Class Current: 700/258
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30
• CPC Class Codes: G06N 7/01 Probabilistic graphical models, e.g. probabilistic networks

Abstract

A robotic mapping method includes scanning a robot across a surface to be mapped. Locations of a plurality of points on the surface are sensed during the scanning. A first of the sensed point locations is selected. A preceding subset of the sensed point locations is determined. The preceding subset is disposed before the first sensed point location along a path of the scanning. A following subset of the sensed point locations is determined. The following subset is disposed after the first sensed point location along the path of the scanning. The first sensed point location is represented in a map of the surface by an adjusted first sensed point location. The adjusted first sensed point location is closer to each of the preceding and following subsets of the sensed point locations than is the first sensed point location.

Claims

1. A robotic mapping method, comprising:

scanning a robot across a surface to be mapped;

sensing locations of a plurality of points on the surface, the sensing occurring during the scanning;

selecting a first said sensed point location;

determining a first subset of the sensed point locations that are within a vicinity of the first sensed point location;

ascertaining a line segment that approximates the first subset of sensed point locations; and

representing the first sensed point location in a map of the surface by an adjusted first sensed point location, the adjusted first sensed point location being closer to the line segment than is the first sensed point location.

2. The method of claim 1 wherein the point locations are sensed in a plurality of scans.

3. The method of claim 1 wherein the selecting, determining, ascertaining and representing steps are repeated for each of the sensed point locations other than the first sensed point location.

4. The method of claim 1 wherein the vicinity of the first sensed point location comprises a circular area having the first sensed point location at a center of the circular area.

5. The method of claim 1 comprising the further step of calculating a probabilistic distribution associated with the adjusted first sensed point location, the probabilistic distribution having a peak value at the line segment and having values decreasing in directions substantially perpendicular to the line segment, the representing step being dependent upon the probabilistic distribution.

6. The method of claim 5 wherein the probabilistic distribution comprises a sub-quadratic normal distribution.

7. The method of claim 6 wherein the sensed point locations are substantially co-planar.

8. A robotic mapping method, comprising:

using a robot to sense locations of a plurality of points on a surface to be mapped; and

representing a first said sensed point location in a map of the surface by an adjusted first sensed point location, the adjusted first sensed point location being dependent upon at least a second sensed point location and a third said sensed point location.

9. The method of claim 8 wherein the robot senses the locations in a plurality of scans of the robot across the surface, at least one of the second and third sensed point locations being sensed in a different scan of the robot than is the first sensed point location.

10. The method of claim 8 comprising the further step of calculating a probabilistic distribution associated with the adjusted first sensed point location, the probabilistic distribution being dependent upon the second and third sensed point locations, the representing step being dependent upon the probabilistic distribution.

11. The method of claim 8 wherein the adjusted first sensed point location is dependent upon a slope of a first imaginary line segment joining the second sensed point location and the third said sensed point location.

12. The method of claim 11 wherein the adjusted first sensed point location is dependent upon a slope of a second imaginary line segment joining the first sensed point location and a fourth sensed point location, the fourth sensed point location being sensed in a same scan of the robot as is the first sensed point location.

13. A robotic mapping method, comprising:

scanning at least one robot across a surface to be mapped, the scanning including a first scan and a second scan;

sensing locations of a plurality of points on the surface, a first set of the sensed point locations being sensed during the first scan, a second set of the sensed point locations being sensed during the second scan;

selecting a first pair of said sensed point locations from the first set, a first imaginary line segment joining the first pair of said sensed point locations having a first slope;

selecting a second pair of said sensed point locations from the second set, the first pair of sensed point locations having a position in a direction of the scanning that substantially corresponds to a position of the second pair of sensed point locations in the direction of the scanning, a second imaginary line segment joining the second pair of said sensed point locations having a second slope; and

representing one of the first pair of sensed point locations in a map of the surface by an adjusted first sensed point location, a third imaginary line segment joining the adjusted first sensed point location and an other sensed point location of the first pair, the third imaginary line segment having a third slope, the third slope being closer to the second slope than is the first slope.

14. The method of claim 13 wherein the one of the first pair of sensed point locations that is adjusted follows the other sensed point location of the first pair along the direction of the scanning.

15. The method of claim 13 wherein the selecting and representing steps are repeated for each of the sensed point locations in the first set.

16. The method of claim 13 comprising the further step of calculating a probabilistic distribution associated with the adjusted first sensed point location, the probabilistic distribution having a peak value disposed at a location where the third slope is approximately equal to the second slope, the distribution having values decreasing in all directions away from the peak value, the representing step being dependent upon the probabilistic distribution.

17. The method of claim 16 wherein the probabilistic distribution comprises a quadratic normal distribution.

18. The method of claim 13 wherein the sensed point locations in the first set and the second set are substantially co-planar.

19. The method of claim 13 wherein the selected first pair of said sensed point location are adjacent to each other.

20. The method of claim 19 wherein the selected second pair of said sensed point location are adjacent to each other.