MANAGEMENT OF RESOURCES FOR SLAM IN LARGE ENVIRONMENTS

• US 20130138246A1
• Filed: 11/09/2012
• Published: 05/30/2013
• Est. Priority Date: 03/25/2005
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Gutmann, Jens-Steffen, Goel, Dhiraj, Munich, Mario E.
• Granted Patent: US 9,250,081 B2
• Time in Patent Office: Days
• US Class Current: 700/253
• CPC Class Codes: G01C 21/12 executed aboard the object being navigated; Dead reckoning
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• 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: G05D 1/028 using a RF signal
• CPC Class Codes: Y10S 901/01 Mobile robot
• CPC Class Codes: Y10S 901/47 Optical

Abstract

Vector Field SLAM is a method for localizing a mobile robot in an unknown environment from continuous signals such as WiFi or active beacons. Disclosed is a technique for localizing a robot in relatively large and/or disparate areas. This is achieved by using and managing more signal sources for covering the larger area. One feature analyzes the complexity of Vector Field SLAM with respect to area size and number of signals and then describe an approximation that decouples the localization map in order to keep memory and run-time requirements low. A tracking method for re-localizing the robot in the areas already mapped is also disclosed. This allows to resume the robot after is has been paused or kidnapped, such as picked up and moved by a user. Embodiments of the invention can comprise commercial low-cost products including robots for the autonomous cleaning of floors.

Claims

1. A method of managing resources for a robot, the method comprising:

associating observations of a first set of one or more continuous signals with a first map;

associating observations of a second set of one or more continuous signals with a second map, wherein the second map is maintained independently the first map; and

switching between performing simultaneous localization and mapping (SLAM) with the first map or performing SLAM with the second map based at least partly on an observed signal strength of the first set or the second set.

2. The method of claim 1, further comprising:

observing a plurality of sets of one or more continuous signals including the first set and the second set, wherein each of the plurality of observed sets is associated with a separate map;

determining that a largest observed signal strength of the plurality of observed sets is larger in magnitude than a signal strength of a set currently being used for performing SLAM; and

switching to performing SLAM with the set with the largest observed signal strength.

3. The method of claim 1, further comprising:

observing a plurality of sets of one or more continuous signals including the first set and the second set, wherein each of the plurality of observed sets is associated with a separate map;

determining that a largest observed signal strength of the plurality of observed sets is at least a predetermined factor larger in magnitude than a signal strength of a set currently being used for performing SLAM; and

switching to performing SLAM with the set with the largest observed signal strength.

4. The method of claim 3, wherein the predetermined factor is a factor of 2.

5. The method of claim 1, wherein the first set of one or more continuous signals and the second set of one or more continuous signals comprise reflections of spots of infrared light.

6. The method of claim 1, further comprising distinguishing among the different reflections of spots of infrared light based on frequency.

7. The method of claim 1, wherein the robot comprises an autonomous robotic cleaner, the method further comprising performing SLAM while cleaning a surface.

8. An apparatus comprising:

a robot;

a controller of the robot configured to;

associate observations of a first set of one or more continuous signals with a first map;

associate observations of a second set of one or more continuous signals with a second map, wherein the second map is maintained independently the first map; and

switch between performing simultaneous localization and mapping (SLAM) with the first map or performing SLAM with the second map based at least partly on an observed signal strength of the first set or the second set.

9. The apparatus of claim 8, wherein the controller is further configured to:

observe a plurality of sets of one or more continuous signals including the first set and the second set, wherein each of the plurality of observed sets is associated with a separate map;

determine that a largest observed signal strength of the plurality of observed sets is larger in magnitude than a signal strength of a set currently being used for performing SLAM; and

switch to performing SLAM with the set with the largest observed signal strength.

10. The apparatus of claim 8, wherein the controller is further configured to:

observe a plurality of sets of one or more continuous signals including the first set and the second set, wherein each of the plurality of observed sets is associated with a separate map;

determine that a largest observed signal strength of the plurality of observed sets is at least a predetermined factor larger in magnitude than a signal strength of a set currently being used for performing SLAM; and

switch to performing SLAM with the set with the largest observed signal strength.

11. The apparatus of claim 10, wherein the predetermined factor is a factor of 2.

12. The apparatus of claim 8, wherein the first set of one or more continuous signals and the second set of one or more continuous signals comprise reflections of spots of infrared light.

13. The apparatus of claim 8, wherein the controller is further configured to distinguish among the different reflections of spots of infrared light based on frequency.

14. The apparatus of claim 8, wherein the robot comprises an autonomous robotic cleaner, wherein the controller is further configured to perform SLAM while the robot is cleaning a surface.

15. An apparatus for managing resources for a robot, the apparatus comprising:

a means for associating observations of a first set of one or more continuous signals with a first map;

a means for associating observations of a second set of one or more continuous signals with a second map, wherein the second map is maintained independently the first map; and

a means for switching between performing simultaneous localization and mapping (SLAM) with the first map or performing SLAM with the second map based at least partly on an observed signal strength of the first set or the second set.