Cleaning robot having carpet detector and method of detecting carpet boundary using the same

• US 20070271004A1
• Filed: 12/06/2006
• Published: 11/22/2007
• Est. Priority Date: 05/19/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Cho, Joon-kee, Bang, Seok-won, Kim, Yeon-ho
• Granted Patent: US 8,346,389 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: A47L 9/2826 the condition of the floor
• 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: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00

Abstract

A cleaning robot having a carpet detector and a method of detecting a carpet boundary using the same, in which the presence of the carpet on a floor is detected. The cleaning robot having a carpet detector includes a main body, a driver fixed to the main body to move the robot, and the carpet detector detecting a carpet when the robot is driven by the driver. The method of detecting a carpet boundary includes detecting a carpet using respective carpet detectors fixed to both wheels of a robot, obtaining a moving distance of the robot for an interval between times at which the respective carpet detectors detect the carpet, and calculating a boundary direction of the carpet with respect to a moving direction of the robot using the moving distance and the interval between the times at which the respective carpet detectors detect the carpet.

Claims

1. A cleaning robot having a carpet detector, comprising:

a main body;

a driver fixed to the main body to move the robot; and

the carpet detector detecting a carpet when the robot is driven by the driver, the carpet detector including

a contact part in contact with the carpet when the robot is moving on the carpet, and

a sensing part sensing motion of the contact part generated by the contact with the carpet.

2. The cleaning robot of claim 1, wherein the contact part includes a rotation part rotating in contact with the carpet when the robot is moving on the carpet.

3. The cleaning robot of claim 2, wherein the sensing part includes a rotation sensor sensing rotation of the rotation part.

4. The cleaning robot of claim 1, wherein the contact part includes:

a plate lifted by contact with the carpet when the robot is moving on the carpet; and

a support fixing the plate to a lower part of the main body and being moved inside a fixing part of the carpet detector when the plate is lifted.

5. The cleaning robot of claim 4, wherein the sensing part includes an optical sensor sensing lifting of the contact part.

6. The cleaning robot of claim 4, wherein the sensing part includes a limit sensor operated by lifting of the contact part.

7. The cleaning robot of claim 4, wherein the sensing part includes a proximity sensor operated by lifting of the contact part.

8. The cleaning robot of claim 4, wherein the sensing part includes a lead sensor operating by lifting of the contact part to sense a magnetic or metallic portion fixed to an upper part of the contact part.

9. The cleaning robot of claim 4, wherein the carpet detector further includes an elastic member that resists movement of the contact part by providing a resilient counter-force.

10. The cleaning robot of claim 1, wherein the carpet detector further includes a fixing part connected to the contact part to guide lifting of the contact part due to contact with the carpet when the robot is moving on the carpet and to fix the carpet detector to a lower or lateral surface of the main body.

11. The cleaning robot of claim 1, wherein the carpet detector further includes a bellows about which the contact part is movable, and the contact part is inclined around the bellows when the robot is in contact with the carpet when moving on the carpet.

12. The cleaning robot of claim 1, wherein the carpet detector further includes a joint part about which the contact part is movable, and the contact part is inclined around the joint part when the robot is in contact with the carpet when moving on the carpet.

13. The cleaning robot of claim 11, wherein the sensing part further includes a sensor sensing that an upper sensing part and a lower sensing part are fixed to and/or detached from each other by the motion of the contact part when the robot is moving on the carpet.

14. The cleaning robot of claim 12, wherein the sensing part further includes a sensor sensing that an upper sensing part and a lower sensing part are fixed to and/or detached from each other by the motion of the contact part when the robot is moving on the carpet.

15. A cleaning robot having a carpet detector, comprising:

a main body;

a driver fixed to the main body to move the robot; and

the carpet detector detecting a carpet when the robot is driven by the driver, the carpet including

a contact part that contact with the carpet when the robot is moving on the carpet, and

a pressure sensor or a touch pad sensing a pressure of the contact part generated by the contact.

16. The cleaning robot of claim 15, wherein the carpet detector further includes a fixing part connected with the contact part in a single body to fix the carpet detector to a lower or lateral surface of the main body.

17. A method of detecting a carpet boundary, comprising:

detecting a carpet using carpet detectors each respectively fixed to a main body proximate to a wheel of a robot;

obtaining a moving distance of the robot for a time interval between times at which the respective carpet detectors detect the carpet; and

calculating a boundary direction of the carpet with respect to a moving direction of the robot using the moving distance and the time interval between the times at which the respective carpet detectors detect the carpet.

18. The method of claim 17, wherein the obtaining includes obtaining the moving distance of the robot by multiplying the time interval by a moving speed of the robot.

19. The method of claim 17, wherein the calculating includes obtaining a moving distance of the carpet detector that first senses the carpet for the time interval.

20. The method of claim 17, wherein the calculating includes calculating a boundary direction θ

of the carpet with respect to the moving direction of the robot using θ

=arc tan(W/D), where D is the moving distance of the robot and W is a distance between the carpet detectors.

21. The method of claim 17, further comprising extracting a carpet boundary by tracking the boundary direction.

22. The method of claim 21, further comprising determining a carpet area when a moving path of the robot forms a closed loop.

23. The method of claim 22, further comprising rotating the robot at a predetermined angle in a direction of the wheel proximate to a carpet detector sensing the carpet, before the robot strays from the carpet.

24. A carpet detector for a movable robot, comprising:

a contact part contacting carpet when the robot moves into or on the carpet; and

a sensing part sensing a motion of the contact part resulting from the contact,

wherein

the contact part includes a roller which rotates when contacting carpet and the sensing part includes a rotation sensor sensing rotation of the roller,

the contact part includes a plate fixed to a support a portion of which extends within a fixing part, the plate being lifted by contact with carpet, and the sensing part senses movement of the contact part by sensing motion of an end of the support caused by a lifting of the plate, or

the contact part includes a plate fixed to a support a portion of which extends within a fixing part, the plate being lifted by contact with carpet, and the sensing part is a touch pad or a pressure sensitive pad at a carpet-contacting surface of the plate.

25. The carpet detector of claim 24, wherein, when the contact part includes a plate, the plate has a convex shape or a partially angled part with a pointed lower part to reduce a contact area with the carpet.

26. A carpet detector for a robot, comprising:

a fixed part connected to the robot;

a contact part movably connected to the fixed part and contacting carpet when the robot moves onto carpet; and

a sensing part sensing motion of the contact part resulting from contact of the contact part with the carpet,

wherein

the contact part is connected to the fixed part by a flexible joint and the sensing part senses flexing of flexible joint, or

the contact part is connected to the fixed part by a hinge and the sensing part senses hinged movement of the contact part about the hinge.

27. The carpet detector of claim 26, wherein the sensing part includes an upper sensing part in the fixed part, a lower sensing part in the contact part, and a contact sensor sensing a contact state between the upper and lower sensing parts, the sensing parts being in contact when the sensing part is not in contact with carpet, and

wherein the sensing part detects the flexing or the hinged movement by sensing detachment of the lower sensing part from the upper sensing part.

28. A method of detecting a carpet boundary using robot having a carpet detector at each wheel, the method comprising:

advancing the robot along a floor so as to make a straight advance to detect a boundary of a carpet on a floor;

tracking the boundary of the carpet by identifying motion states or pressure states of the carpet detectors;

determining whether the tracked boundary is a closed loop;

determining, when the tracked boundary is not a closed loop, whether wheels of the robot have strayed from the carpet and repeating the determining whether the tracking boundary is a closed loop, when the wheels have not strayed from the carpet; and

rotating the robot toward a wheel on the carpet, when wheels of the robot have strayed from the carpet.

29. The method of claim 28, wherein, in the rotating, when the carpet has a square shape, the robot is rotated at an angle of at least 90°

and, when the carpet has a polygonal or circular shape, the robot is rotated at a predetermined angle.