Autonomous robot localization

• US 10,067,232 B2
• Filed: 12/05/2016
• Issued: 09/04/2018
• Est. Priority Date: 10/10/2014
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Halloran, Mike, Milliken, Jamie, Pierce, Travis, Peters, Eric Charles
• Primary Examiner(s): Nolan, Peter D
• Application Number:
  US15/368,894
• Publication Number:
  US 20170146654A1
• Time in Patent Office: 638 Days
• CPC Class Codes: A01D 2101/00 Lawn-mowers
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: G01S 13/46 Indirect determination of position data
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/48 Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/4868 Controlling received signal intensity or exposure of sensor
• CPC Class Codes: G05D 1/0236 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0259 using magnetic or electromagnetic means

Abstract

A location estimation system for use with an autonomous lawn mowing robot, comprises a plurality of synthetic surfaces positioned with respect to a mowable space in an environment, a radiation source coupled to the lawn mowing robot, a detector coupled to the lawn mowing robot and configured to detect radiation reflected by objects in the environment, and a controller configured to controllably direct radiation from the radiation source to scan the environment, and to vary at least one of an output power of the directed radiation and a scan rate of the directed radiation, as a function of detected radiation reflected from one or more of the synthetic surfaces.

Claims

1. A method of estimating a location of a lawn mowing robot in an environment having a plurality of synthetic surfaces at known locations with respect to a mowable space in the environment, the method comprising:

placing a lawn mowing robot in the environment, the lawn mowing robot comprising;

a radiation source coupled to the lawn mowing robot;

a detector coupled to the lawn mowing robot and configured to detect radiation reflected by objects in the environment;

a modulator coupled to the radiation source and configured to modulate radiation emitted from the radiation source; and

a controller configured to controllably direct radiation from the radiation source to scan the environment, and to vary at least one of an output power of the directed radiation or a scan rate of the directed radiation as a function of detected radiation reflected from one or more of the synthetic surfaces, wherein the controller is configured to direct the modulator to vary a radiation beam focus in response to detection of reflected radiation; and

using the controller to controllably direct the radiation from the radiation source to scan the environment and determine the location of the lawn mowing robot based on the detected reflected radiation.

2. The method of claim 1, wherein the controller is configured to vary the scan rate of the radiation source.

3. The method of claim 1, wherein the controller is configured to direct the modulator to vary the output power of the radiation source in response to detection of reflected radiation.

4. The method of claim 3, wherein the modulator scans a portion of a second scan at a scan speed different from at least a portion of the scan speed of a first scan.

5. The method of claim 4, wherein the scan speed of the second scan is slower than the scan speed of the first scan.

6. The method of claim 1, wherein the controller scans the environment during a motion of the lawn mowing robot.

7. The method of claim 1, further comprising scanning the environment by rotating a portion of the radiation source.

8. The method of claim 1, further comprising:

comparing, by the controller, data indicative of detected reflected radiation to stored data; and

identifying a particular object as being associated with the stored data based on the comparison.

9. The method of claim 1, further comprising modulating the output power of the radiation source.

10. The method of claim 1, wherein a reduced radiation beam focus corresponds to a faster spin rate of the directed radiation, and an increased radiation beam focus corresponds to a slower spin rate of the directed radiation.

11. The method of claim 1, wherein a reduced radiation beam focus corresponds to pings of directed radiation at larger degree increments, and an increased radiation beam focus corresponds to pings of directed radiation at smaller degree increments.

12. The method of claim 11 in which a ratio of the degree increments for the pings in the increased radiation beam focus versus that of the reduced radiation beam focus is between 0.1 and 0.8.

13. The method of claim 1, wherein the controller is configured to fan the radiation source at an angle relative to both horizontal and vertical directions.

14. A method of estimating a location of a lawn mowing robot in an environment that includes a plurality of synthetic surfaces at known locations with respect to a mowable space in the environment, the method comprising:

scanning a radiation source coupled to a lawn mowing robot present in the environment;

receiving radiation, by one or more detectors of the lawn mowing robot, reflected by objects in the environment;

varying an output power of the directed radiation as a function of the radiation reflected from one or more of the synthetic surfaces;

varying a scan rate of the directed radiation, as a function of detected radiation reflected from one or more of the synthetic surfaces;

estimating a location of the lawn mowing robot; and

varying a beam focus of the radiation source as a function of detected radiation reflected from one or more of the synthetic surfaces.

15. The method of claim 14, wherein the radiation source is a laser.

16. The method of claim 14, wherein two or more detectors responsive to different wavelengths are employed to detect radiation.

17. The method of claim 14, wherein scanning comprises rotating a portion of the radiation source.

18. The method of claim 14, wherein a reduced radiation beam focus corresponds to a faster spin rate of the directed radiation, and an increased radiation beam focus corresponds to a slower spin rate of the directed radiation.

19. The method of claim 14, wherein a reduced radiation beam focus corresponds to pings of directed radiation at larger degree increments, and an increased radiation beam focus corresponds to pings of directed radiation at smaller degree increments.

20. The method of claim 19 in which a ratio of the degree increments for the pings in the increased radiation beam focus versus that of the reduced radiation beam focus is between 0.1 and 0.8.

21. The method of claim 14, comprising fanning the radiation source at an angle relative to both horizontal and vertical directions.

22. A lawn mowing robot for operating in an environment having a plurality of synthetic surfaces at known locations with respect to a mowable space in the environment, the lawn mowing robot comprising:

a radiation source coupled to the lawn mowing robot;

a detector coupled to the lawn mowing robot and configured to detect radiation reflected by objects in the environment;

a modulator coupled to the radiation source and configured to modulate radiation emitted from the radiation source; and

a controller configured to controllably direct radiation from the radiation source to scan the environment, vary at least one of an output power of the directed radiation or a scan rate of the directed radiation as a function of detected radiation reflected from one or more of the synthetic surfaces, direct the modulator to vary a radiation beam focus in response to detection of reflected radiation, and determine the location of the lawn mowing robot based on the detected reflected radiation.

23. The lawn mowing robot of claim 22, wherein the controller is configured to vary the scan rate of the radiation source.

24. The lawn mowing robot of claim 22, wherein the controller is configured to direct the modulator to vary the output power of the radiation source in response to detection of reflected radiation.

25. The lawn mowing robot of claim 24, wherein the modulator is configured to scan a portion of a second scan at a scan speed different from at least a portion of the scan speed of a first scan.

26. The lawn mowing robot of claim 25, wherein the scan speed of the second scan is slower than the scan speed of the first scan.

27. The lawn mowing robot of claim 22, wherein the controller is configured to scan the environment during a motion of the lawn mowing robot.

28. The lawn mowing robot of claim 22, wherein the controller is configured to controllably direct the radiation to scan the environment by rotating a portion of the radiation source.

29. The lawn mowing robot of claim 22, wherein the controller is configured to:

compare data indicative of detected reflected radiation to stored data; and

identify a particular object as being associated with the stored data based on the comparison.

30. The lawn mowing robot of claim 22, wherein the controller is configured to modulate the output power of the radiation source.