MOBILE ROBOT AND METHOD OF LOCALIZATION AND MAPPING OF THE SAME

• US 20140244094A1
• Filed: 02/26/2014
• Published: 08/28/2014
• Est. Priority Date: 02/28/2013
• Status: Active Grant

• Current Assignee: Korea Advanced Institute of Science and Technology, Samsung Electronics Co. Ltd.
• Original Assignee: Korea Advanced Institute of Science and Technology, Samsung Electronics Co. Ltd.
• Inventors: KIM, In Joo, Kim, Shin, Lee, Seung Mok, Myeong, Hyeon, Park, Byeol Teo, Park, Ji Eun, Jung, Jong Dae
• Granted Patent: US 9,164,509 B2
• Time in Patent Office: Days
• US Class Current: 701/23
• CPC Class Codes: G05D 1/021 specially adapted to land vehicles
• 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 2201/0203 Cleaning or polishing vehicle

Abstract

A method of localization and mapping of a mobile robot may reduce position errors in localization and mapping using a plurality of vector field sensors. The method includes acquiring a relative coordinate in a movement space using an encoder, acquiring an absolute coordinate in the movement space by detecting intensity and direction of a signal using vector field sensors, defining a plurality of virtual cells on a surface of the movement space such that each of the cells has a plurality of nodes having predetermined positions, and updating position information about the nodes of the cells based on the relative coordinate acquired through the encoder and the absolute coordinate acquired through the vector field sensors and implementing localization and mapping in the movement space in a manner that position information of a new node is estimated while position information of a previous node is determined.

Claims

1. A method of localization and mapping of a mobile robot comprising:

acquiring a relative coordinate in a movement space using an encoder;

acquiring an absolute coordinate in the movement space by detecting at least one of intensity and direction of a signal using a plurality of vector field sensors;

defining a plurality of virtual cells on a surface of the movement space such that each of the cells has a plurality of nodes having predetermined positions; and

updating position information about the plurality of nodes of at least one of the cells based on the relative coordinate acquired through the encoder and the absolute coordinate acquired through the vector field sensors and implementing localization and mapping in the movement space such that position information of a new node among the plurality of nodes is estimated while position information of a previous node among the plurality of nodes is determined.

2. The method according to claim 1, wherein the updating is performed when the mobile robot is positioned in one virtual cell among the plurality of virtual cells.

3. The method according to claim 2, further comprising calculating and applying weights for each of node among the plurality of nodes when the mobile robot is positioned in one virtual cell among the plurality of virtual cells.

4. The method according to claim 1, further comprising initializing a node among the plurality of nodes connected to another node among the plurality of nodes to be extended when the mobile robot moves from one virtual cell among the plurality of virtual cells to another virtual cell among the plurality of virtual cells.

5. The method according to claim 4, wherein the initializing is performed based on a mean value and a covariance value of the connected node.

6. The method according to claim 1, wherein the localization and mapping is performed by fast simultaneous localization and mapping (SLAM).

7. The method according to claim 1, further comprising compensating for an error of the relative coordinate acquired through the encoder using the absolute coordinate acquired through the plurality of vector field sensors.

8. The method according to claim 1, wherein the relative coordinate is an odometry coordinate comprising an x coordinate, a y coordinate and an angle of travel direction of the mobile robot.

9. The method according to claim 1, wherein the plurality of virtual cells have a continuity there between.

10. The method according to claim 9, wherein the plurality of nodes configuring each of the plurality of virtual cells have a continuity therebetween.

11. The method according to claim 1, wherein each of the plurality of vector field sensors is a magnetic field sensor.

12. The method according to claim 1, wherein each of the plurality of vector field sensors is a Wi-Fi received signal strength indicator.

13. The method according to claim 1, wherein each of the plurality of vector field sensors is an FM receiver.

14. The method according to claim 1, wherein at least two of the plurality of vector field sensors are arranged at a front and back of the mobile robot in a travel direction of the mobile robot.

15. A mobile robot comprising:

an encoder to acquire a relative coordinate in a movement space;

a plurality of vector field sensors to acquire an absolute coordinate in the movement space by detecting at least one of intensity and direction of a signal; and

a controller to define a plurality of virtual cells on a surface of the movement space such that each of the cells has a plurality of nodes having predetermined positions and to update position information about the plurality of nodes of at least one of the virtual cells among the plurality of virtual cells based on the relative coordinate acquired through the encoder and the absolute coordinate acquired through the plurality of vector field sensors and implement localization and mapping in the movement space such that position information of a new node among the plurality of nodes is estimated while position information of a previous node among the plurality of nodes is determined.

16. The mobile robot according to claim 15, wherein the controller updates the position information about the plurality of nodes when the mobile robot is positioned in one virtual cell among the plurality of virtual cells.

17. The mobile robot according to claim 16, wherein the controller calculates and applies a weight for each node among the plurality of nodes when the mobile robot is positioned in one virtual cell among the plurality of virtual cells.

18. The mobile robot according to claim 15, wherein the controller initializes a node among the plurality of nodes connected to another node among the plurality of nodes to be extended when the mobile robot moves from one virtual cell the plurality of virtual cells to another virtual cell among the plurality of virtual cells.

19. The mobile robot according to claim 18, wherein initializing the connected node is performed based on a mean value and a covariance value of the connected node.

20. The mobile robot according to claim 15, wherein the localization and mapping is performed by applying fast simultaneous localization and mapping (SLAM).

21. The mobile robot according to claim 15, wherein the controller compensates for an error of the relative coordinate acquired through the encoder using the absolute coordinate acquired through the plurality of vector field sensors.

22. The mobile robot according to claim 15, wherein the relative coordinate is an odometry coordinate comprising an x-coordinate, a y-coordinate and an angle of travel direction of the mobile robot.

23. The mobile robot according to claim 15, wherein the plurality of virtual cells have a continuity therebetween.

24. The mobile robot according to claim 23, wherein the plurality of nodes configuring each of the plurality of virtual cells have a continuity therebetween.

25. The mobile robot according to claim 15, wherein each of the plurality of vector field sensors is a magnetic field sensor.

26. The mobile robot according to claim 15, wherein each of the plurality of vector field sensors is a Wi-Fi received signal strength indicator.

27. The mobile robot according to claim 15, wherein each of the plurality of vector field sensors is an FM receiver.

28. The mobile robot according to claim 15, wherein at least two of the plurality of vector field sensors are arranged at a front and back of the mobile robot in a travel direction of the mobile robot.