METHODS AND APPARATUS FOR POSITION ESTIMATION USING REFLECTED LIGHT SOURCES

• US 20120022785A1
• Filed: 08/05/2011
• Published: 01/26/2012
• Est. Priority Date: 03/29/2004
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: Evolution Robotics Inc. (iRobot Corporation)
• Inventors: DiBernardo, Enrico, Pirjanian, Paolo
• Granted Patent: US 8,295,955 B2
• Time in Patent Office: Days
• US Class Current: 701/514
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01C 3/06 Use of electric means to obtain final indication
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• 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 5/163 Determination of attitude using inertial means G01C9/00; control of attitude G05D1/49
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70

Abstract

The invention is generally related to the estimation of position and orientation of an object with respect to a local or a global coordinate system using reflected light sources. A typical application of the method and apparatus includes estimation and tracking of the position of a mobile autonomous robot. Other applications include estimation and tracking of an object for position-aware, ubiquitous devices. Additional applications include tracking of the positions of people or pets in an indoor environment. The methods and apparatus comprise one or more optical emitters, one or more optical sensors, signal processing circuitry, and signal processing methods to determine the position and orientation of at least one of the optical sensors based at least in part on the detection of the signal of one or more emitted light sources reflected from a surface.

Claims

1. A location estimation system for estimating a location of a self-propelled object, the system comprising:

a first guidance device comprising;

a first modulator;

a first light source coupled to the first modulator,

wherein the first modulator is configured to modulate light of the first light source using a first modulation;

wherein the first light source is configured to project modulated light,

whereby a first spot is projected onto a first surface when the first light source is positioned for operation with the self-propelled object;

a second guidance device comprising;

a second modulator;

a second light source coupled to the second modulator,

wherein the second modulator is configured to modulate light of the second light source using a second modulation, the second modulation distinct from the first modulation;

wherein the second light source is configured to project modulated light,

whereby a second spot is projected onto a second surface when the second light source is positioned for operation with the self-propelled object;

a first detector configured to;

detect the first light spot based at least in part on the first modulation;

detect the second light spot based at least in part on the second modulation;

a data processing unit configured to;

determine that the self-propelled object is in a first room at least partly in response to detecting the first light spot;

determine a first location of the self-propelled object based at least in part on the first light spot;

determine that the self-propelled object is in a second room at least partly in response to detecting the second light spot; and

determine a second location of the self-propelled object based at least in part on the second light spot.

10. The location estimation system of claim 10, wherein the first detector includes a plurality of photodetectors.

2. The location estimation system as defined in claim 10, wherein:

the first modulation provides a differing light intensity, light pattern, wavelength, or combination thereof as compared to the second modulation;

the location estimation system is configured to distinguish the first light spot from the second light spot based on the first modulation and the second modulation;

the location estimation system is configured to determine the position of the self-propelled object, wherein the position includes a heading, orientation, distance measurement, speed of the object, or combination thereof;

the first light source comprises at least one light-emitting diode (LED), infrared light device, polarized light device, laser diode, or combination thereof;

the self-propelled object is an autonomous robot; and

the location estimation system is configured to determine the robot'"'"'s position relative to a reference coordinate system for localization.

3. The location estimation system as defined in claim 10, wherein the location estimation system is further configured to build a topological map including connectivity of the first room and the second room.

4. The location estimation system as defined in claim 10, wherein the first surface is a ceiling.

5. The location estimation system as defined in claim 10, wherein the first modulation is a first frequency modulation and the second modulation is a second frequency modulation.

6. The location estimation system as defined in claim 10, wherein the first modulation is a first pattern.

7. The location estimation system as defined in claim 10, wherein the first light spot comprises at least two light spots, and the second light spot comprises at least two light spots.

8. The location estimation system of claim 10, wherein the first light source further comprises a collimating lens.

9. The location estimation system as defined in claim 10, wherein the location estimation system is configured to perform pose estimation of the self-propelled object.

11. The location estimation system of claim 10, wherein the location estimation system is configured to maintain a history of paths traversed by the self-propelled object.

12. The location estimation system as defined in claim 10, wherein the self-propelled object is a floor cleaning device.

13. The location estimation system as defined in claim 10, wherein the first detector is mounted on the self-propelled object.

14. A method of estimating a location of a self-propelled object, the method comprising:

in a first guidance device;

modulating light of a first light source via a first modulator using a first modulation;

projecting first modulated light from the first light source to form a first spot on a first surface;

in a second guidance device;

modulating light of a second light source via a second modulator using a second modulation;

projecting second modulated light from the second light source to form a second spot on a second surface;

detecting the first light spot based at least in part on the first modulation;

detecting the second light spot based at least in part on the second modulation;

determining that the self-propelled object is in a first room at least partly in response to detecting the first light spot;

estimating a first location of the self-propelled object based at least in part on the first light spot;

determining that the self-propelled object is in a second room at least partly in response to detecting the second light spot; and

estimating a second location of the self-propelled object based at least in part on the second light spot.

15. The method as defined in claim 1400, wherein:

the first modulation provides a differing light intensity, light pattern, wavelength, or combination thereof as compared to the second modulation,

the first light source comprises at least one light-emitting diode (LED), infrared light device, polarized light device, laser diode, or combination thereof,

the self-propelled object is an autonomous robot,

the method further comprising;

distinguishing the first light spot from the second light spot based on the first modulation and the second modulation;

determining the position of the self-propelled object, wherein the position includes a heading, orientation, distance measurement, speed of the object, or combination thereof; and

determining the robot'"'"'s position relative to a reference coordinate system for localization.

16. The method as defined in claim 140, the method further comprising building a topological map including connectivity of the first room and the second room.

17. The method as defined in claim 140, wherein the first surface is a ceiling.

18. The method as defined in claim 140, wherein the first modulation is a first frequency modulation and the second modulation is a second frequency modulation.

19. The method as defined in claim 140, wherein the first modulation is a first pattern.

20. The method as defined in claim 140, wherein the first light spot comprises at least two light spots, and the second light spot comprises at least two light spots.