Method for tracking movement of a mobile robotic device

Patent metadata

Field	Value
Publication number	US-11241791-B1
Application number	US-201916554040-A
Country	US
Kind code	B1
Filing date	Aug 28, 2019
Priority date	Apr 17, 2018
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

Provided is a tangible, non-transitory, machine readable medium storing instructions that when executed by the processor effectuates operations including: capturing visual readings to objects within an environment; capturing readings of wheel rotation; capturing readings of a driving surface; capturing distances to obstacles; determining displacement of the robotic device in two dimensions based on sensor readings of the driving surface; estimating, with the processor, a corrected position of the robotic device to replace a last known position of the robotic device; determining a most feasible element in an ensemble based on the visual readings; and determining a most feasible position of the robotic device as the corrected position based on the most feasible element in the ensemble and the visual readings.

First claim

The invention claimed is:

1. A robotic device, comprising:
a chassis;
a set of wheels coupled to the chassis;
one or more electric motors for rotating the set of wheels;
one or more tools for performing work coupled to the chassis;
a processor electronically coupled to a plurality of sensors; and
a tangible, non-transitory, machine readable medium storing instructions that when executed by the processor effectuates operations comprising:
capturing, with a visual sensor, visual readings to objects within an environment of the robotic device as the robotic device moves within the environment;
capturing, with an encoder sensor, readings of wheel rotation indicative of displacement of the robotic device;
capturing, with an optoelectronic sensor, readings of a driving surface of the environment of the robotic device;
capturing, with a depth sensor, distances to obstacles as the robot moves within the environment;
determining, with the processor, displacement of the robotic device in two dimensions based on the optoelectronic sensor readings of the driving surface;
determining, with the processor, a difference in displacement between the displacement determined based on the encoder sensor readings and the displacement determined based on the optoelectronic sensor readings of the driving surface, the difference in displacement being indicative of slippage;
estimating, with the processor, a corrected position of the robotic device to replace a last known position of the robotic device, wherein:
estimating a corrected position of the robotic device occurs if the processor loses or reduces knowledge of a current position of the robotic device in relation to a global frame of reference of the environment of the robotic device when the robotic device moves along a path from the last known position to a new intended position while performing work using the one or more tools;
the processor creates or updates an ensemble of simulated positions of possible new locations of the robotic device wherein some elements of the ensemble are based on the readings of wheel rotation from the encoder sensor and the displacement readings determined from the optoelectronic sensor readings;

determining, by the processor, a most feasible element in the ensemble based on the visual readings; and
determining, by the processor, a most feasible position of the robotic device as the corrected position based on the most feasible element in the ensemble and the visual readings.

2. The robotic device of claim 1 , wherein the processor eliminates simulated positions of possible new locations of the robotic device from the ensemble having a probability of being true below a predetermined threshold.

3. The robotic device of claim 1 , wherein the processor assigns a higher to the sensor readings associated with the most feasible element in the ensemble when estimating future corrected positions of the robotic device.

4. The robotic device of claim 1 , wherein the optoelectronic sensor comprises at least one imaging sensor and at least one light source.

5. The robotic device of claim 4 , wherein the optoelectronic sensor captures sequential images of the driving surface and the processor determines displacement of the robotic device in two dimensions based on the captured images.

6. The robotic device of claim 4 , wherein the at least one light source comprises a laser and an LED.

7. The robotic device of claim 6 , wherein the processor alternates the light source when an image quality value is below a predetermined threshold.

8. The robotic device of claim 7 , wherein the processor discards optoelectronic sensor readings with image quality values below the predetermined threshold.

9. The robotic device of claim 1 , the operations further comprising dividing, with the processor, the environment into two or more zones and actuating, with the processor, the robotic device to cover at least one of the two or more zones.

10. The robotic device of claim 1 , the operations further comprising detecting, with the processor, a floor type based on the optoelectronic sensor readings.

11. The robotic device of claim 10 , the operations further comprising adjusting, with the processor, settings of the robotic device based on the floor type detected, wherein the settings comprise one or more of: a wheel motor speed, an impeller motor speed, a brush motor speed, a pump motor speed, a liquid release mechanism speed, expanding or contracting a wheel, activating or deactivating vacuuming, activating or deactivating mopping, and activating or deactivating a liquid release mechanism.

12. The robotic device of claim 1 , the operations further comprise determining, with the processor, a level of debris accumulation based on at least the optoelectronic sensor readings.

13. The robotic device of claim 12 , wherein the operations further comprise marking, with the processor, the locations and levels of debris accumulation within a map of the environment and determining, with the processor, a movement path of the robotic device based on the locations and levels of debris accumulation within the environment.

14. The robotic device of claim 12 , the operations further comprising adjusting, with the processor, settings of the robotic device based on the level of dirt accumulation, wherein the settings comprise one or more of: a wheel motor speed, an impeller motor speed, a brush motor speed, a pump motor speed, a liquid release mechanism speed, expanding or contracting a wheel, activating or deactivating vacuuming, activating or deactivating mopping, and activating or deactivating a liquid release mechanism.

15. The robotic device of claim 1 , the operations further comprising generating, with the processor, a navigational path of the robotic device based on real-time sensor readings.

16. The robotic device of claim 1 , wherein at least some data processing associated with the readings of the plurality of sensors is offloaded to cloud storage.

17. The robotic device of claim 1 , wherein the processor effectuates the operations using only the readings captured by the encoder sensor if the processor determines that the readings captured by the optoelectronic sensor are unreliable; or wherein the processor effectuates the operations using only the readings captured by the optoelectronic sensor if the processor determines that the readings captured by the encoder sensor are unreliable.

18. The robotic device of claim 1 , wherein the robotic device is a surface cleaning robotic device.

19. A tangible, non-transitory, machine readable medium storing instructions that when executed by a processor effectuates operations comprising:
capturing, with a visual sensor, visual readings to objects within an environment of a robotic device as the robotic device moves within the environment;
capturing, with an encoder sensor, readings of wheel rotation indicative of displacement of the robotic device;
capturing, with an optoelectronic sensor, readings of a driving surface of the environment of the robotic device;
capturing, with a depth sensor, distances to obstacles as the robot moves within the environment;
determining, with the processor, displacement of the robotic device in two dimensions based on the optoelectronic sensor readings of the driving surface;
determining, with the processor, a difference in displacement between the displacement determined based on the encoder sensor readings and the displacement determined based on the optoelectronic sensor readings of the driving surface, the difference i

Assignees

• Ebrahimi Afrouzi Ali
• Fath Lukas
• Zhang Chen
• Highfill Brian
• Ai Inc

Inventors

• Ebrahimi Afrouzi Ali
• Fath Lukas
• Zhang Chen
• Highfill Brian

Classifications

• G06T7/277

  involving stochastic approaches, e.g. using Kalman filters · CPC title

• B25J13/088

  with position, velocity or acceleration sensors · CPC title

• G06T2207/30252

  Vehicle exterior; Vicinity of vehicle · CPC title

• G01P3/806

  in devices of the type to be classified in G01P3/68 · CPC title

• G01C22/02 Primary

  by conversion into electric waveforms and subsequent integration, e.g. using tachometer generator {(G01C22/002, G01C22/004, G01C22/006 take precedence)} · CPC title