Autonomous machine

• US 7,085,624 B2
• Filed: 10/31/2002
• Issued: 08/01/2006
• Est. Priority Date: 11/03/2001
• Status: Expired due to Fees

• Current Assignee: Dyson Technology Limited (Beeswax Holdings UK Limited)
• Original Assignee: Dyson Technology Limited (Beeswax Holdings UK Limited)
• Inventors: Shardlow, Andrew Michael, Aldred, Michael David
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Marc, McDieunel
• Application Number:
  US10/494,300
• Publication Number:
  US 20050085947A1
• Time in Patent Office: 1,370 Days
• Field of Search: 700/253, 700/245, 318/568.12, 701/23
• US Class Current: 700/253
• CPC Class Codes: G05B 2219/45098 Vacuum cleaning robot
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• 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 1/0272 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

Abstract

An autonomous machine is configured to explore the area in which it is located, constructing a map of the area based on information collected by the machine as the machine explores the area. The machine determines when it has returned to a previously visited position within the area. The map is corrected when the machine returns to the previously visited position, based on the knowledge that the current position and the previously visited position are the same.

Claims

1. An autonomous machine comprising:

a drive for moving the machine along a surface, and

a navigation system, including a memory, for navigating the machine around an area,

the navigation system comprising;

an exploration unit causing the machine to explore a boundary of the area in which it is located, constructing a map of the area based on information collected by the machine as the machine explores the area,

a determining unit determining when the machine has returned to a previously visited position within the area, and

a corrector correcting the map when the machine returns to the previously visited position, based on knowledge that the current position and the previously visited position are the same.

2. An autonomous machine according to claim 1, wherein the corrector is configured to distribute any error among the points on the map which has been constructed.

3. An autonomous machine according to claim 2, wherein the exploring unit is configured to store path information on a path travelled by the machine as the machine follows the boundary;

and the determining unit is configured to determine when the machine has returned to a previously visited position in the area by comparing the latest section of the path travelled by the machine with information representing a section of the path previously stored in the memory, and for deciding when the new path information and previously stored path information are substantially the same.

4. An autonomous machine according to claim 3, wherein the path information is stored at regular intervals.

5. An autonomous machine according to claim 4, wherein the path information is stored at intervals which are spaced by an equal distance from one another.

6. An autonomous machine according to claim 3, 4 or 5, wherein the path information is representative of a change in direction of the machine as the machine follows the boundary of the area.

7. An autonomous machine according to claim 3, 4 or 5, wherein the navigation system is configured to derive, from the stored path information, a second set of path information which is a less detailed representation of the travelled path.

8. An autonomous machine according to claim 7, wherein the navigation system is configured to use the second set of path information in deciding whether the new path information and previously stored path information are substantially the same.

9. An autonomous machine according to claim 1, wherein the exploring unit is configured to store path information on a path travelled by the machine as the machine follows the boundary;

and the determining unit is configured to determine when the machine has returned to a previously visited position in the area by comparing the latest section of the path travelled by the machine with information representing a section of the path previously stored in the memory, and for deciding when the new path information and previously stored path information are substantially the same.

10. An autonomous machine according to claim 9, wherein the path information is stored at regular intervals.

11. An autonomous machine according to claim 10, wherein the path information is stored at intervals which are spaced by an equal distance from one another.

12. An autonomous machine according to claim 9, 10 or 11, wherein the path information is representative of a change in direction of the machine as the machine follows the boundary of the area.

13. An autonomous machine according to claim 12, wherein the path information is a relative change in direction of the machine compared to a previous point at which path information was stored.

14. An autonomous machine according to claim 9, 10 or 11, wherein the navigation system is configured to derive, from the stored path information, a second set of path information which is a less detailed representation of the travelled path.

15. An autonomous machine according to claim 14, wherein the navigation system is configured to use the second set of path information in deciding whether the new path information and previously stored path information are substantially the same.

16. An autonomous machine according to claim 9, 10 or 11, wherein the navigation system further comprises a sensor sensing another parameter and storing this other parameter in the memory along with the path information as the machine follows the boundary of the area.

17. An autonomous machine according to claim 16, wherein the navigation system also uses, on at least some occasions, the other parameter to determine when the machine has returned to a previously visited position in the area.

18. An autonomous machine according to claim 17, wherein the other parameter is an absolute direction of the machine.

19. A method of controlling an autonomous machine comprising:

causing the machine to explore a boundary of the area in which it is located,

constructing a map of the area based on information collected by the machine as the machine explores the area,

determining when the machine has returned to a previously visited position within the area, and

correcting the map when the machine returns to the previously visited position, based on the knowledge that the current position and the previously visited position are the same.

20. A computer-readable storage medium storing a program which, when executed by an autonomous machine, causes the machine to perform a method, the method comprising:

causing the machine to explore a boundary of the area in which it is located,

constructing a map of the area based on information collected by the machine as the machine explores the area,

determining when the machine has returned to a previously visited position within the area, and

correcting the map when the machine returns to the previously visited position, based on the knowledge that the current position and the previously visited position are the same.