Method for tracking movement of a mobile robotic device

• US 10,436,810 B1
• Filed: 04/17/2018
• Issued: 10/08/2019
• Est. Priority Date: 04/17/2018
• Status: Active Grant

• Current Assignee: Al, Inc.
• Original Assignee: Al, Inc.
• Inventors: Afrouzi, Ali Ebrahimi
• Primary Examiner(s): Bekele, Mekonen T
• Application Number:
  US15/955,480
• Publication Number:
  US 20190317121A1
• Time in Patent Office: 539 Days
• CPC Class Codes: G01C 22/00 Measuring distance traversed on the ground by vehicles, persons, animals or other moving solid bodies, e.g. using odometers, using pedometers
• CPC Class Codes: G01C 22/02 by conversion into electric waveforms and subsequent integration, e.g. using tachometer generator G01C22/002, G01C22/004, G01C22/006 take precedence
• CPC Class Codes: G01P 3/38 using photographic means
• CPC Class Codes: G01P 3/68 using optical means, i.e. using infrared, visible, or ultraviolet light G01P3/80 takes precedence ; by reflection of waves G01S17/58
• CPC Class Codes: G01P 3/806 in devices of the type to be classified in G01P3/68
• CPC Class Codes: G06T 2207/30241 Trajectory
• CPC Class Codes: G06T 2207/30252 Vehicle exterior; Vicinity of vehicle
• CPC Class Codes: G06T 7/254 involving subtraction of images
• CPC Class Codes: G06T 7/262 using transform domain methods, e.g. Fourier domain methods

Abstract

A method for tracking movement and turning angle of a mobile robotic device using two optoelectronic sensors positioned on the underside thereof. Digital image correlation is used to analyze images captured by the optoelectronic sensors and determine the amount of offset, and thereby amount of movement of the device. Trigonometric analysis of a triangle formed by lines between the positions of the optoelectronic sensors at different intervals may be used to determine turning angle of the mobile robotic device.

Claims

1. A method for tracking movement of a robotic device comprising:

Capturing a plurality of images of a driving surface by each of at least two optoelectronic sensors of the robotic device moving within an environment;

Obtaining, with one or more processors of the robotic device, the plurality of images by each of the at least two optoelectronic sensors;

Determining, with one or more processors of the robotic device, based on the images captured by each of the at least two optoelectronic sensors, linear movement of each of the at least two optoelectronic sensors; and

Determining, with one or more processors of the robotic device, based on the linear movement of each of the at least two optoelectronic sensors, rotational movement of the robotic device.

2. The method of claim 1, wherein the linear movement of the at least two optoelectronic sensors is equal to linear movement of the robotic device.

3. The method of claim 1, wherein the linear movement of each of the at least two optoelectronic sensors is determined by maximum cross correlation between successive images captured by each of the at least two optoelectronic sensors.

4. The method of claim 1, further comprising determining linear velocity of the robotic device, by the one or more processors of the robotic device, based on linear movement, of the robotic device and the time between the captured images, the linear movement of the robotic device being estimated from the captured images.

5. The method of claim 1, further comprising determining angular velocity of the robotic device, by the one or more processors of the robotic device, based on linear movement, of the at least two optoelectronic sensors and the time between the captured images, the linear movement of the at least two optoelectronic sensors being estimated from the captured images.

6. The method of claim 1, wherein images captured by each of the at least two optoelectronic sensors overlap with preceding images captured by each of the at least two optoelectronic sensors.

7. The method of claim 1, wherein the driving surface is illuminated by a light source.

8. The method of claim 7, wherein the light source is an LED.

9. A method for tracking velocity of a robotic device comprising:

Capturing a plurality of images of a driving surface by each of at least two optoelectronic sensors of the robotic device moving within an environment;

Obtaining with one or more processors of the robotic device, the plurality of images by each of the at least two optoelectronic sensors; and

Determining, with the one or more processors of the robotic device, based on images captured by each of the at least two optoelectronic sensors, linear movement of each of the at least two optoelectronic sensors.

10. The method of claim 9, further comprising determining linear velocity of the robotic device, by the one or more processors of the robotic device, based on the linear movement of each of the at least two optoelectronic sensors and time between the images captured.

11. The method of claim 9, further comprising determining angular velocity of the robotic device, by the one or more processors of the robotic device, based on the linear movement of each of the at least two optoelectronic sensors and time between the images captured.

12. The method of claim 9, wherein determining the linear movement of each of the at least two optoelectronic sensors further comprises determining maximum cross correlation between successive images captured by each of the at least two optoelectronic sensors.

13. The method of claim 9, wherein the plurality of images captured by each of the at least two optoelectronic sensors overlaps with preceding images captured by each of the at least two optoelectronic sensors.

14. The method of claim 9, wherein the driving surface is illuminated by a light source.

15. The method of claim 14, wherein the light source is an LED.

16. A method for tracking movement of a robotic device comprising:

Capturing a plurality of images of a driving surface by at least one optoelectronic sensor of the robotic device moving within an environment;

Obtaining, with one or more processors of the robotic device, the plurality of images by the at least one optoelectronic sensor;

Determining, with one or more processors of the robotic device, based on the images captured by the at least one optoelectronic sensor, linear movement of the optoelectronic sensor; and

Determining, with one or more processors of the robotic device, based on the linear movement of the at least one optoelectronic sensor, rotational movement of the robotic device.

17. The method of claim 16, wherein the linear movement of the at least one optoelectronic sensor is determined by maximum cross correlation between successive images captured by the at least one optoelectronic sensor.

18. The method of claim 16, wherein the linear movement of the at least one optoelectronic sensor is equal to linear movement of the robotic device.

19. The method of claim 16, further comprises determining linear velocity of the robotic device, by the one or more processors of the robotic device, based on the linear movement of the at least one optoelectronic sensor and the time between the captured images, the linear movement of the at least one optoelectronic sensor being estimated from the captured images.

20. The method of claim 16, further comprises determining angular velocity of the robotic device, by one or more processors of the robotic device, based on the linear movement of the at least one optoelectronic sensor and the time between the captured images, the linear movement of the at least one optoelectronic sensor being estimated from the captured images.

21. The method of claim 16, wherein images captured by the at least one optoelectronic sensor overlaps with preceding images captured by the at least one optoelectronic sensor.

22. The method of claim 16, wherein the rotational movement is about an instantaneous center of rotation located at a center of the robotic device.

23. The method of claim 16, wherein the rotational movement is about an instantaneous center of rotation located at a wheel of the robotic device.

24. The method of claim 16, wherein the driving surface is illuminated by a light source.

25. The method of claim 24, wherein the light source is an LED.