SYSTEMS AND METHODS FOR EXTENDING SLAM TO MULTIPLE REGIONS
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.
1 . A method of performing simultaneous localization and mapping (SLAM) for a robot, the method comprising:
performing SLAM in a first area associated with a first map;
performing SLAM in a second area associated with a second map; and
performing position estimation in a third area outside of and between the first area and the second area, wherein in the third area, position estimation is performed with dead reckoning.
2 . The method of claim 1 , wherein dead reckoning is performed using odometry and a gyroscope.
3 . The method of claim 1 , further comprising:
resetting a timer upon entry of the robot into the third area;
tracking time spent in the third area with the timer; and
returning to at least one of the first area or the second area after a predetermined elapsed time in the third area.
4 . The method of claim 1 , further comprising:
resetting a timer upon entry of the robot into the third area from the first area or the second area;
remembering which one of the first area or the second area the robot was in prior to entry to the third area;
tracking time spent in the third area with the timer; and
returning to the one of the first area or the second area from which the robot was in prior to entry to the third area after elapsing of a predetermined time in the third area unless the robot enters an area in which SLAM can be performed at least with positioning information based on observations of a set of one or more continuous signals.
5 . The method of claim 1 , further comprising:
estimating a position uncertainty of the robot while operating in the third area; and
if the position uncertainty is larger than a predetermined threshold, returning to at least one of the first area or the second area.
6 . The method of claim 1 , further comprising:
estimating a position uncertainty of the robot while operating in the third area;
remembering which one of the first area or the second area the robot was in prior to entry to the third area; and
if the position uncertainty is larger than a predetermined threshold, returning to the one of the first area or the second area from which the robot was in prior to entry to the third area.
7 . The method of claim 1 , wherein in the first area, SLAM is performed at least with positioning information based on observations of a first set of one or more continuous signals, wherein in the second area, SLAM is performed at least with positioning information based on observations of a second set of one or more continuous signals.
8 . The method of claim 7 , 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.
9 . The method of claim 8 , further comprising distinguishing among the different reflections of spots of infrared light based on frequency.
10 . The method of claim 1 , wherein the robot comprises an autonomous robotic cleaner, further comprising performing SLAM while cleaning a surface.
11 . An apparatus comprising:
a robot;
a controller of the robot configured to:
perform SLAM in a first area associated with a first map;
perform SLAM in a second area associated with a second map; and
perform position estimation in a third area outside of and between the first area and the second area, wherein in the third area, position estimation is performed with dead reckoning.
12 . The apparatus of claim 11 , wherein the controller is configured to perform dead reckoning using odometry and a gyroscope.
13 . The apparatus of claim 11 , wherein the controller is further configured to:
reset a timer upon entry of the robot into the third area;
track time spent in the third area with the timer; and
return to at least one of the first area or the second area after a predetermined elapsed time in the third area.
14 . The apparatus of claim 11 , wherein the controller is further configured to:
reset a timer upon entry of the robot into the third area from the first area or the second area;
remember which one of the first area or the second area the robot was in prior to entry to the third area;
track time spent in the third area with the timer; and
return to the one of the first area or the second area from which the robot was in prior to entry to the third area after elapsing of a predetermined time in the third area unless the robot enters an area in which SLAM can be performed at least with positioning information based on observations of a set of one or more continuous signals.
15 . The apparatus of claim 11 , wherein the controller is further configured to:
estimate a position uncertainty of the robot while operating in the third area; and
if the position uncertainty is larger than a predetermined threshold, return to at least one of the first area or the second area.
16 . The apparatus of claim 11 , wherein the controller is further configured to:
estimate a position uncertainty of the robot while operating in the third area;
remember which one of the first area or the second area the robot was in prior to entry to the third area; and
if the position uncertainty is larger than a predetermined threshold, return to the one of the first area or the second area from which the robot was in prior to entry to the third area.
17 . The apparatus of claim 11 , wherein in the first area, the controller is configured to perform SLAM at least with positioning information based on observations of a first set of one or more continuous signals, and wherein in the second area, the controller is configured to perform SLAM at least with positioning information based on observations of a second set of one or more continuous signals.
18 . The apparatus of claim 17 , 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.
19 . The apparatus of claim 18 , wherein the controller is further configured to distinguish among the different reflections of spots of infrared light based on frequency.
20 . The apparatus of claim 11 , wherein the robot comprises an autonomous robotic cleaner, wherein the controller is configured to perform SLAM while cleaning a surface.
21 . An apparatus for performing simultaneous localization and mapping (SLAM) for a robot, the apparatus comprising:
a means for performing SLAM in a first area associated with a first map and in a second area associated with a second map; and
a means for performing position estimation in a third area outside of and between the first area and the second area, wherein in the third area, position estimation is performed with dead reckoning.