MOBILE ROBOT AND METHOD OF CONTROLLING THE SAME

• US 20170332872A1
• Filed: 05/17/2017
• Published: 11/23/2017
• Est. Priority Date: 05/17/2016
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: JUN, Woochan, SUNG, Chulmo
• Granted Patent: US 10,517,456 B2
• Time in Patent Office: Days
• CPC Class Codes: A47L 11/24 Floor-sweeping machines, motor-driven
• CPC Class Codes: A47L 11/4005 Arrangements of batteries or cells; Electric power supply arrangements
• CPC Class Codes: A47L 11/4011 Regulation of the cleaning machine by electric means; Control systems and remote control systems therefor
• CPC Class Codes: A47L 11/4044 Vacuuming or pick-up tools; Squeegees
• CPC Class Codes: A47L 11/4061 Steering means; Means for avoiding obstacles; Details related to the place where the driver is accommodated
• CPC Class Codes: A47L 11/4066 Propulsion of the whole machine
• CPC Class Codes: A47L 2201/022 Recharging of batteries
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: A47L 5/22 with rotary fans
• CPC Class Codes: A47L 9/0472 Discs
• CPC Class Codes: A47L 9/0477 Rolls
• CPC Class Codes: A47L 9/0488 Combinations or arrangements of several tools, e.g. edge cleaning tools
• CPC Class Codes: A47L 9/2852 Elements for displacement of the vacuum cleaner or the accessories therefor, e.g. wheels, casters or nozzles
• CPC Class Codes: A47L 9/2884 Details of arrangements of batteries or their installation
• CPC Class Codes: A47L 9/30 Arrangement of illuminating devices
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G05D 1/0088 characterized by the autonomous decision making process, e.g. artificial intelligence, predefined behaviours using knowledge based models G06N5/00
• CPC Class Codes: G05D 1/0238 using obstacle or wall sensors G05D1/0246 and G05D1/0289 take precedence; lidar systems designed for anti-collision purposes G01S17/93
• CPC Class Codes: G05D 1/0248 in combination with a laser lasers per se H01S
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: G06V 10/145 : Illumination specially adapted for pattern recognition, e.g. using gratings
• CPC Class Codes: G06V 20/10 : Terrestrial scenes scenes under surveillance with static cameras G06V20/52; scenes perceived from the exterior of a vehicle G06V20/56; scenes perceived from the interior of a vehicle G06V20/59
• CPC Class Codes: G06V 20/36 : Indoor scenes
• CPC Class Codes: G06V 20/58 : Recognition of moving objects or obstacles, e.g. vehicles or pedestrians; Recognition of traffic objects, e.g. traffic signs, traffic lights or roads

Abstract

A mobile robot of the present disclosure includes a first pattern emission unit configured to emit a first patterned light downward and forward from the main body on a floor of an area to be cleaned; and an image acquisition unit configured to acquire an image of first patterned light emitted by the first pattern emission unit and incident on an obstacle. A pattern is detected from the acquired image to determine an obstacle, and a cliff is detected based on at least one of a shape or a position of the pattern in the image. The mobile robot may identify a travel path that does not lead to the cliff.

Claims

1. A mobile robot, comprising:

a main body configured to travel in an area to be cleaned and to suck foreign materials on a floor of the area to be cleaned;

a camera provided on a front portion of the main body and configured to capture an image of a prescribed area;

a first light source provided on the front portion of the main body and configured to emit a first patterned light at a downward angle toward a first sub-region of the prescribed area; and

a controller configured to;

detect whether the image captured by camera includes a first optical pattern corresponding to the first patterned light,

identify an obstacle in the prescribed area based on the first optical pattern, and

control a movement of the main body relative to the obstacle,

wherein the controller, when identifying the obstacle, is further configured to determine that the obstacle includes a cliff based on at least one of a shape or location of the first optical pattern in the image.

2. The mobile robot of claim 1, further comprising:

a second light source provided below the first light source on the front portion of the main body and configured to emit a second patterned light toward a second sub-region of the prescribed area that is positioned above the first sub-region, and

wherein the controller is further configured to;

detect, in the image captured by camera, a second optical pattern corresponding to a portion of the second patterned light, and

identify the obstacle in the prescribed area further based on the second optical pattern.

3. The mobile robot of claim 2, wherein the controller is further configured to determine that the obstacle extends above a top portion of the main body when the image includes the second optical pattern.

4. The mobile robot of claim 2, wherein the first light source, the second light source, and the camera are vertically aligned on the front portion of the main body.

5. The mobile robot of claim 2, wherein the camera is provided between the first light source and the second light source.

6. The mobile robot of claim 4, wherein the first light source and the second light source are to be vertically symmetric to each other such that the first light source emits at an angle below horizontal and the second light source emits at a corresponding angle above horizontal.

7. The mobile robot of claim 2, wherein:

the first patterned light includes a first horizontal line segment; and

the second patterned light includes a second horizontal line segment.

8. The mobile robot of claim 7, wherein the first patterned light further includes a vertical line segment that intersects the first horizontal line segment.

9. The mobile robot of claim 1, wherein the controller is further configured to determine that the cliff located to a side of a travelling direction of the mobile robot when first optical pattern includes the portion of first patterned light and excludes another portion of the first patterned light.

10. The mobile robot of claim 8, wherein the controller, when controlling the movement of the main body, is further configured to cause the mobile robot to change the travel direction away the side associated with the cliff.

11. The mobile robot of claim 1, wherein the controller is further configured to determine that the cliff is located in a travelling direction of the mobile robot when controller determines that the image excludes the first optical pattern.

12. The mobile robot of claim 11, further comprising:

a cliff sensor positioned on a bottom portion of the main body and facing a floor being cleaned by the mobile robot,

wherein, when determining that the image excludes the first optical pattern, the controller further configured to;

control the main body to move forward a prescribed distance, and

verify, using the cliff sensor, a presence of the cliff.

13. The mobile robot of claim 12, wherein the cliff sensor is configured to determine a distance between the cliff sensor and a surface under the cliff sensor, and

wherein the controller, when controlling the movement of the main body relative to the obstacle, is further configured to:

cause the mobile robot to move away from the obstacle when the distance between the cliff sensor and the surface under the cliff sensor is greater than or equal to a threshold distance, and

cause the mobile robot to move toward the obstacle when the distance between the cliff sensor and the surface under the cliff sensor is less than the threshold distance.

14. The mobile robot of claim 1, wherein the controller, based on determining that the cliff is located in the travelling direction of the mobile robot, is further configured to control the main body to move backward a prescribed distance after detecting the cliff, and rotate by a prescribed angle of rotation after moving backwards the prescribed distance.

15. The mobile robot of claim 1, wherein the controller, when controlling the movement of the main body, is further configured to cause the mobile robot to move in a first direction to another location after detecting the cliff,

wherein the camera is further configured to capture another image at the other location, and

wherein the controller is further configured to:

identify, in the other image, another first optical pattern corresponding to at least a portion of the first patterned light emitted by the first light source at the other location,

compare one or more dimensions of the other first optical pattern to one or more dimensions of the first optical pattern, and

control the movement of the main body based on the comparison the one or more dimensions of the other first optical pattern to the one or more dimensions of the first optical pattern.

16. The mobile robot of claim 15, wherein the controller is further configured to:

cause the mobile robot to continue in the first direct when the one or more dimensions of the other first optical pattern correspond to or are larger than the one or more dimensions of the first optical pattern, and

cause the robot to rotate and move in a second direction that is different from the first direction when the one or more dimensions of the other first optical pattern are smaller than the one or more dimensions of the first optical pattern.

17. The mobile robot of claim 1, wherein the controller, when controlling the movement of the main body, is further configured to cause the mobile robot to move to another location after detecting the cliff,

wherein the camera is further configured to capture, at the other location, another image of another prescribed area, and

wherein the controller is further configured to determine that an obstacle is not present in the other prescribed area when the other image includes another first optical pattern corresponding to at least a portion of the first patterned light emitted by the first light source at the other location, and the other first optical pattern is located at a reference position within the other image, the reference position corresponding to a portion of the other image where the other first optical pattern would be positioned when the first patterned light does not intersect an obstacle in the other prescribed area.

18. The mobile robot of claim 1, wherein the controller is further configured to identify an edge of the obstacle based on a difference between a shape of the first optical pattern and a shape of the first patterned light or the second patterned light.

19. The mobile robot of claim 1, wherein the first light source includes a laser diode (LD) or a light-emitting diode (LED) to generate light and an optical pattern projection element (OPPE) to convert the light into the first patterned light.

20. The mobile robot of claim 1, wherein the camera is positioned below the first light source.