Magnetic navigation systems for autonomous mobile robots

Patent metadata

Field	Value
Publication number	US-11320835-B2
Application number	US-201916707840-A
Country	US
Kind code	B2
Filing date	Dec 9, 2019
Priority date	Dec 11, 2018
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

An autonomous mobile robot includes a drive system to maneuver the autonomous mobile robot about an environment, a first magnetic field antenna system responsive to a magnetic field pulse to generate a first signal, and a second magnetic field antenna system responsive to the magnetic field pulse to generate a second signal. The magnetic field pulse is emitted by a magnetic field emitter system in the environment. The autonomous mobile robot further includes a controller to execute instructions to perform operations including reorienting the autonomous mobile robot based on the first signal and the second signal.

First claim

What is claimed is:

1. An autonomous mobile robot comprising:
a drive system to maneuver the autonomous mobile robot about an environment;
a first magnetic field antenna system configured to detect a magnetic field pulse emitted by a magnetic field emitter system of a charging station in the environment and to generate a first signal responsive to detecting the magnetic field pulse;
a second magnetic field antenna system configured to detect the magnetic field pulse and to generate a second signal responsive to detecting the magnetic field pulse, wherein the first magnetic field antenna system and the second magnetic field antenna system are spaced apart from one another in a direction perpendicular to a forward drive direction of the autonomous mobile robot; and
a controller configured to perform operations comprising reorienting the autonomous mobile robot relative to the charging station based on a difference between the first signal and the second signal.

2. The autonomous mobile robot of claim 1 , wherein:
the operations comprise moving, in a docking operation, the autonomous mobile robot toward the charging station using mapping data until the autonomous mobile robot is within a predetermined distance from the charging station; and
reorienting the autonomous mobile robot based on the difference between the first signal and the second signal comprises reorienting, in the docking operation, the autonomous mobile robot relative to the charging station in response to the autonomous mobile robot being within the predetermined distance from the charging station and based on the first signal and the second signal.

3. The autonomous mobile robot of claim 2 , wherein the operations comprise:
after reorienting the autonomous mobile robot relative to the charging station in response to the autonomous mobile robot being within the predetermined distance from the charging station, moving the autonomous mobile robot toward the charging station and reorienting the autonomous mobile robot relative to the charging station such that a difference between distances of the first and second magnetic field antenna systems to the magnetic field emitter system decreases.

4. The autonomous mobile robot of claim 1 , further comprising a battery configured to be charged at the charging station comprising the magnetic field emitter system,
wherein the operations comprise initiating a docking operation to move the autonomous mobile robot to the charging station to charge the battery,
wherein reorienting the autonomous mobile robot comprises reorienting the autonomous mobile robot during the docking operation.

5. The autonomous mobile robot of claim 4 , wherein reorienting the autonomous mobile robot comprises reorienting the autonomous mobile robot in response to determining the first magnetic field antenna system is closer to the charging station than the second magnetic field antenna system is to the charging station.

6. The autonomous mobile robot of claim 5 , wherein reorienting the autonomous mobile robot in response to determining the first magnetic field antenna system is closer to the charging station than the second magnetic field antenna system is to the charging station comprises reorienting the autonomous mobile robot in response to the first signal and the second signal indicating that the first magnetic field antenna system is closer to the charging station than the second magnetic field antenna system is to the charging station.

7. The autonomous mobile robot of claim 5 , wherein determining the first magnetic field antenna system is closer to the charging station than the second magnetic field antenna system is to the charging station comprises:
determining that a strength of the magnetic field pulse detected at the first magnetic field antenna system is greater than a strength of the magnetic field pulse at the second magnetic field antenna system.

8. The autonomous mobile robot of claim 5 , wherein the first signal generated by the first magnetic field antenna system comprises a clipped portion, and the second signal generated by the second magnetic field antenna system comprises a clipped portion, wherein a duration of the clipped portion of the first signal is greater than a duration of the clipped portion of the second signal.

9. The autonomous mobile robot of claim 8 , wherein the operations further comprise:
obtaining a first value by extrapolating a declining portion of the first signal;
obtaining a second value by extrapolating a declining portion of the second signal; and
determining that the first signal and the second signal indicate that the first magnetic field antenna system is closer to the charging station than the second magnetic field antenna system is to the charging station based on the first value being greater than the second value.

10. The autonomous mobile robot of claim 4 , wherein the battery is configured to be charged by a magnetic field emitted by the magnetic field emitter system of the charging station.

11. The autonomous mobile robot of claim 4 , wherein initiating the docking operation to move the autonomous mobile robot to the charging station to charge the battery comprises initiating the docking operation to move the autonomous mobile robot to a charging position in which the autonomous mobile robot is positioned above at least a portion of the magnetic field emitter system of the charging station.

12. The autonomous mobile robot of claim 11 , wherein, in the charging position, the autonomous mobile robot is positioned above an inductive coil of the magnetic field emitter system of the charging station.

13. The autonomous mobile robot of claim 4 , wherein the magnetic field emitter system is a first magnetic field emitter, and the battery is configured to be charged by a second magnetic field emitter system of the charging station.

14. The autonomous mobile robot of claim 4 , wherein the operations further comprise:
moving the autonomous mobile robot in response to determining that the autonomous mobile robot is misaligned with the charging station as the charging station performs a charging operation to charge the battery of the autonomous mobile robot.

15. The autonomous mobile robot of claim 4 , wherein the operations further comprise:
as the charging station performs a charging operation to charge the battery of the autonomous mobile robot, periodically communicating with the charging station to indicate a presence of the autonomous mobile robot at the charging station.

16. The autonomous mobile robot of claim 4 , wherein the operations further comprise:
as the charging station performs a charging operation to charge the battery of the autonomous mobile robot, communicating with the charging station to indicate a presence of the autonomous mobile robot at the charging station, wherein communicating with the charging station comprises producing a capacitance change detectable by the charging station.

17. The autonomous mobile robot of claim 1 , further comprising a navigation sensor configured to generate mapping data as the autonomous mobile robot moves about the environment,
wherein the operations comprise:
navigating the autonomous mobile robot toward the magnetic field emitter system based on the mapping data, and then
navigating, in response to determining that the autonomous mobile robot is within a distance from the magnetic field emitter system, the autonomous mobile robot based on outputs of the first magnetic field antenna system and outputs of the second magnetic field antenna system.

18. The au

Assignees

• Irobot Corp

Inventors

• Hook Frederic D
• Romanov Nikolai
• Mercaldo Matthew
• Teulings Peter
• Holm Jr Kenneth
• Oxoby Juan

Classifications

• G05D1/0088

  characterized by the autonomous decision making process, e.g. artificial intelligence, predefined behaviours (using knowledge based models G06N5/00) · CPC title

• G05D1/0274

  using mapping information stored in a memory device (navigation using map-matching G01C21/30) · CPC title

• G05D1/0225 Primary

  involving docking at a fixed facility, e.g. base station or loading bay (parking aids B62D15/027) · CPC title

• G05D1/028

  using a RF signal · CPC title

• G05D1/0261 Primary

  using magnetic plots · CPC title