Autonomouse machine

• US 20050085947A1
• Filed: 10/31/2002
• Published: 04/21/2005
• Est. Priority Date: 11/03/2001
• Status: Active Grant

• Current Assignee: Dyson Technology Limited (Beeswax Holdings UK Limited)
• Original Assignee: Dyson Technology Limited (Beeswax Holdings UK Limited)
• Inventors: Shardlow, Adrew Michael, Aldred, Michael David
• Granted Patent: US 7,085,624 B2
• Time in Patent Office: Days
• 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 explores 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:

driving means for moving the machine along a surface, and

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

the navigation system comprising;

means for causing the machine to explore a boundary of the area in which it located, constructing a map of the area based on information collected by the machine as the machine explores the area,

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

means for 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.

2. An autonomous machine according to claim 1 wherein the correcting means distributes any error among the points on the map which has been constructed.

3. An autonomous machine according to claim 1 or 2 wherein the exploring means is arranged to store path information on the path travelled by the machine as the machine follows the boundary;

and the determining means is arranged 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 form one another.

6. An autonomous machine according to any one of claims 3-5 wherein the path information is representative of the change in direction of the machine as the machine follows the boundary of the area.

7. An autonomous machine according to claims 6 wherein the path information is the relative change in direction of the machine compared to a previous point at which path information was stored.

8. An autonomous machine according to any one of claims 3-7 wherein the navigation system is arranged to derive, from the stored path information, a second set of path information which is a less detailed representation of the travelled path.

9. An autonomous machine according to claim 8 wherein the comparison means is arranged to use the second set of path information in deciding whether the new path information and previously stored path information are substantially the same.

10. An autonomous machine according to any one of claims 3-9 wherein the navigation system also comprises means for sensing another parameter and for storing this other parameter in the memory along with the path information as the machine follows the boundary of the area.

11. An autonomous machine according to claim 10 wherein the comparison means 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.

12. An autonomous machine according to claim 10 or 11 wherein the other parameter is the absolute direction of the machine.

13. 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,

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.

14. Software for controlling an autonomous machine to perform the method according to claim 13.

15. An autonomous machine, a method of controlling an autonomous machine or software method for controlling an autonomous machine substantially as described herein with reference to the accompanying drawings.