Mobile robot

Patent metadata

Field	Value
Publication number	US-12150608-B2
Application number	US-201917786999-A
Country	US
Kind code	B2
Filing date	Dec 20, 2019
Priority date	Dec 20, 2019
Publication date	Nov 26, 2024
Grant date	Nov 26, 2024

Abstract

The present disclosure provides a mobile robot. The mobile robot includes a body, a pair of spin mops rotatably mounted to the body, a mop motor configured to provide a driving force to the pair of spin mops, an optical flow sensor configured to obtain bottom-view image information using light at a regular time interval, and a controller configured to determine whether the material of the floor is a troublesome material based on the bottom-view image information sensed by the optical flow sensor and to control, upon determining that the material of the floor is a troublesome material, the mop motor to perform an entry restriction operation.

First claim

What is claimed is:

1. A mobile robot, comprising:
a body;
a pair of spin mops rotatably mounted to the body;
a mop motor configured to provide a driving force to the pair of spin mops;
an optical flow sensor configured to obtain bottom-view image information using light at a regular time interval; and
a controller configured to determine whether a material of a floor is a troublesome material based on the bottom-view image information sensed by the optical flow sensor and to control, upon determining that the material of the floor is a troublesome material, the mop motor to perform an entry restriction operation,
wherein the controller is further configured to calculate a frame rate of a bottom-view image based on the bottom-view image information, and when the frame rate is lower than a predetermined reference frame rate, determine that the material of the floor is a troublesome material.

2. The mobile robot according to claim 1 , wherein the optical flow sensor is disposed further forwards than the pair of spin mops.

3. The mobile robot according to claim 1 , wherein the optical flow sensor comprises:
an image sensor configured to capture the bottom-view image to obtain the bottom-view image information; and
at least one light source configured to adjust a quantity of light.

4. The mobile robot according to claim 1 , wherein the controller is further configured to calculate an image quality value of the bottom-view image based on the bottom-view image information, and when the image quality value is smaller than a predetermined reference image quality value, determine that the material of the floor is a troublesome material.

5. The mobile robot according to claim 4 , wherein the image quality value is determined based on a shape of an image formed on the floor by light emitted from a light source.

6. The mobile robot according to claim 1 , wherein the controller is configured to calculate a reflectance value of the floor based on the bottom-view image information, and when the reflectance value of the floor is smaller than a predetermined reference reflectance value, determine that the material of the floor is a troublesome material.

7. The mobile robot according to claim 1 , wherein the controller is further configured to calculate, based on the bottom-view image information, a reflectance value of the floor, an image quality value of the bottom-view image, and the frame rate of the bottom-view image, and determine that the material of the floor is a troublesome material when at least one of Conditions 1 to 3 below is satisfied:
the image quality value is smaller than a predetermined reference image quality value  <Condition 1>

the frame rate is lower than a predetermined reference frame rate  <Condition 2>

the reflectance value of the floor is smaller than a predetermined reference reflectance value.  <Condition 3>

8. The mobile robot according to claim 1 , further comprising:
a camera or a 3D sensor configured to obtain top-view image information at a regular time interval,
wherein the controller is further configured to detect a current location based on the top-view image information.

9. The mobile robot according to claim 8 , wherein, upon determining that the material of the floor is a troublesome material, the controller is further configured to set the current location as a troublesome region.

10. The mobile robot according to claim 1 , further comprising:
a mop load information sensor configured to sense a load value of the mop motor,
wherein, when the load value of the mop motor is larger than a predetermined reference load value, the controller is further configured to control the mop motor to perform the entry restriction operation.

11. The mobile robot according to claim 1 , further comprising:
a cliff sensor configured to sense a distance to the floor,
wherein, when the distance to the floor is less than a reference distance value, the controller is further configured to control the mop motor to perform the entry restriction operation.

12. The mobile robot according to claim 11 , wherein the cliff sensor is disposed further forwards than the pair of spin mops.

13. The mobile robot according to claim 11 , wherein the cliff sensor is disposed such that at least a portion thereof overlaps an imaginary central vertical plane in a vertical direction.

14. The mobile robot according to claim 1 , further comprising:
an acceleration sensor mounted to the body to sense acceleration values,
wherein the controller is further configured to calculate an average acceleration value based on the acceleration values, and upon determining that the average acceleration value is larger than a reference average acceleration value, control the mop motor to perform the entry restriction operation.

15. The mobile robot according to claim 1 , further comprising:
an acceleration sensor mounted to the body to sense acceleration values,
wherein the controller is further configured to calculate dispersion of the acceleration values, and upon determining that the dispersion is greater than reference dispersion, control the mop motor to perform the entry restriction operation.

16. The mobile robot according to claim 1 , further comprising:
a mop load information sensor configured to sense a load value of the mop motor;
a cliff sensor configured to sense a distance to the floor; and
an acceleration sensor mounted to the body to sense acceleration values,
wherein, when at least one of Conditions 4 to 7 below is satisfied, the controller is configured to control the mop motor to perform the entry restriction operation:
the load value of the mop motor is larger than a predetermined reference load value  <Condition 4>

the distance to the floor is less than a predetermined reference distance value  <Condition 5>

an average acceleration value is larger than a predetermined reference average acceleration value  <Condition 6>

dispersion of acceleration is greater than predetermined reference dispersion.  <Condition 7>

17. A mobile robot, comprising:
a body;
a pair of spin mops rotatably mounted to the body;
a mop motor configured to provide a driving force to the pair of spin mops;
an optical flow sensor configured to obtain bottom-view image information using light at a regular time interval;
an acceleration sensor mounted to the body to sense acceleration values;
a cliff sensor configured to sense a distance to the floor;
a mop load information sensor configured to sense a load value of the mop motor; and
a controller configured to determine whether a material of a floor is a troublesome material based on information received from at least one of the optical flow sensor, the acceleration sensor, the cliff sensor, or the mop load information sensor and to control, upon determining that the material of the floor is a troublesome material, the mop motor to perform an entry restriction operation,
wherein the controller is further configured to calculate a frame rate of a bottom-view image based on the bottom-view image information, and when the frame rate is lower than a predetermined reference frame rate, determine that the material of the floor is a troublesome material.

18. The mobile robot according to claim 17 , wherein the optical flow sensor is disposed at a position further forward than a line connecting rotation axes of the pair of spin mops so as not to vertically overlap the pair of spin mops, and
wherein the cliff sensor is disposed further forwards than front ends of the pair of spin mops a

Assignees

• Lg Electronics Inc

Inventors

• Bae Yonghwan

Classifications

• G05D1/83

  Limitation of acceleration or structural stress · CPC title

• G05D1/249

  from positioning sensors located off-board the vehicle, e.g. from cameras · CPC title

• A47L2201/06

  Control of the cleaning action for autonomous devices; Automatic detection of the surface condition before, during or after cleaning · CPC title

• A47L2201/04

  Automatic control of the travelling movement; Automatic obstacle detection · CPC title

• G05D1/0246

  using a video camera in combination with image processing means · CPC title