Moving distance sensing apparatus for robot cleaner and method therefor

• US 20060100741A1
• Filed: 03/23/2005
• Published: 05/11/2006
• Est. Priority Date: 11/11/2004
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Jung, Il-Kyun
• Granted Patent: US 7,706,921 B2
• Time in Patent Office: Days
• US Class Current: 700/258
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93

Abstract

Disclosed are a moving distance sensing apparatus for a robot cleaner and a method therefor capable of determining a precise moving distance with respect to the robot cleaner by setting a long distance sensor and a short distance sensor having respectively different sensing method from each other on the same sensing line in the robot cleaner to sense the long distance and the short distance for the same direction, and then by determining coherency to each moving distance on the basis of information provided by the two different sensors, the moving distance sensing apparatus comprising: a long distance sensor for sensing a moving distance with respect to a long distance; a short distance sensor mounted on the same sensing line in one-to-one correspondence with the long distance sensor, for sensing a moving distance with respect to a short distance; and a micro computer for determining a moving distance error on the basis of moving distance information with respect to the same direction provided by the long distance sensor and the short distance sensor.

Claims

1. A moving distance sensing apparatus for a robot cleaner, comprising:

a long distance sensor for sensing a moving distance with respect to a long distance;

a short distance sensor mounted on the same sensing line in one-to-one correspondence with the long distance sensor, for sensing a moving distance with respect to a short distance; and

a micro computer for determining a moving distance error on the basis of moving distance information with respect to the same direction provided by the long distance sensor and the short distance sensor.

2. The sensing apparatus of claim 1, wherein the long distance sensor is a ultrasonic sensor.

3. The sensing apparatus of claim 1, wherein the short distance sensor is an infrared sensor.

4. The sensing apparatus of claim 1, wherein the long distance sensor is mounted on an outer circumferential surface of the robot cleaner at a uniform interval and also mounted on the same sensing line in one-to-one correspondence with the short distance sensor.

5. The sensing apparatus of claim 1, wherein as the robot cleaner gets close to or away from a predetermined cleaning path or an arbitrary path, the micro-computer compares a moving distance rate sensed by the long distance sensor with a moving distance rate sensed by the short distance sensor, and determines a moving distance error depending on the compared result.

6. The sensing apparatus of claim 5, wherein the micro computer compares the moving distance value sensed by the long distance sensor with the moving distance value sensed by the short distance sensor with respect to an area where the sensing area of the long distance sensor overlaps with the sensing area of the short distance sensor, and determines a moving distance error based on the compared result.

7. A moving distance sensing apparatus of a robot cleaner comprising:

a ultrasonic sensor mounted on an outer circumferential surface of the robot cleaner at a uniform interval, and also mounted on the same sensing line in one-to-one correspondence with an infrared sensor, for sensing a moving distance with respect to a long distance;

an infrared sensor mounted on the same sensing line in one-to-one correspondence with the ultrasonic sensor, for sensing a moving distance with respect to a short distance; and

a micro-computer for determining a moving distance error on the basis of moving distance information with respect to the same direction provided by the ultrasonic sensor and the infrared sensor.

8. The sensing apparatus of claim 7, wherein if the moving distance of a long distance sensed by the ultrasonic sensor and the moving distance of a short distance sensed by the infrared sensor are coherently increased or decreased relatively to each other during a movement of the robot cleaner, it is determined as a precise distance sensed value by the micro computer, and if not, the micro-computer determines that there has occurred error.

9. The sensing apparatus of claim 8, wherein the micro-computer directly compares the moving distance value sensed by the ultrasonic sensor with the moving distance value sensed by the infrared sensor with respect to an area where the moving distance sensed by the ultrasonic sensor overlaps with the moving distance sensed by the infrared sensor, and determines the moving distance error on the basis of the compared result.

10. The sensing apparatus of claim 7, wherein the micro-computer carries out a command to stop a movement of the robot cleaner or reduce its moving speed in case of error occurrence.

11. The sensing apparatus of claim 7, wherein when a decreasing rate with respect to the moving distance sensed by the ultrasonic sensor is coherent to a decreasing rate with respect to the moving distance sensed by the infrared sensor as the robot cleaner gets close to a specific object while moving along a predetermined cleaning path, the micro-computer determines the moving distance value of the robot cleaner as a precise value.

12. The sensing apparatus of claim 7, wherein when an increasing rate with respect to the moving distance sensed by the ultrasonic sensor is coherent to an increasing rate with respect to the moving distance sensed by the infrared sensor as the robot cleaner gets close to a specific object while moving along a predetermined cleaning path, the micro-computer determines the moving distance value of the robot cleaner as a precise value.

13. A method for sensing a moving distance of a robot cleaner comprising the steps of:

sensing the moving distance with respect to a long distance by a long distance sensor and a moving distance with respect to a short distance by a short distance sensor while the robot cleaner moves;

calculating a decreasing rate or an increasing rate for the moving distance sensed by the respective sensors; and

in case that the decreasing rates or the increasing rates for the respectively calculated moving distance are coherent to each other, recognizing the moving distances as precise values, while in case that they are not coherent to each other, determining that there has occurred an error.

14. The method of claim 13, wherein the long distance sensor is a ultrasonic sensor and the short distance sensor is an infrared sensor.

15. The method of claim 13, further comprising the step in which the micro-computer instructs to stop a movement of the robot cleaner or reduce speed thereof, in case of occurring error due to inequality of the decreasing rate or the increasing rate thereof.

16. The method of claim 13, further comprising the step of directly comparing the moving distance value sensed by the long distance sensor with the moving distance value sensed by the short distance sensor with respect to the area where an area sensed by the long distance sensor overlaps with an area sensed by the short distance sensor, and then determining the moving distance error on the basis of the compared result.

17. A method for sensing a moving distance comprising the steps of:

setting a long distance sensor and a short distance sensor having respectively different sensing method from each other in a body of a robot cleaner on the same sensing line;

simultaneously sensing moving distances for a long distance and a short distance, respectively, for the same direction by the sensors, and then calculating decreasing rates or increasing rates with respect to the sensed moving distances; and

comparing the decreasing rates or the increasing rates to determine whether to be coherent to each other, and then determining error for the moving distances.

18. The method of claim 17, wherein the step of calculating the decreasing rates or the increasing rates includes the steps of:

determining whether the robot cleaner gets close to or away from a predetermined cleaning path or an arbitrary path; and

when the robot cleaner gets close to the predetermined path, sensing a long distance by the long distance sensor to calculate the long distance decreasing rate according to a movement of the robot cleaner, and sensing a short distance by the short distance sensor to calculate the short distance decreasing rate according to the movement of the robot cleaner.

19. The method of claim 17, wherein the step of calculating the decreasing rates or the increasing rates includes the steps of:

determining whether the robot cleaner gets close to or away from a predetermined cleaning path or an arbitrary path; and

when the robot cleaner gets away from the predetermined path, sensing a short distance by the short distance sensor to calculate the short distance increasing rate according to a movement of the robot cleaner, and sensing a long distance by the long distance sensor to calculate the long distance increasing rate according to the movement of the robot cleaner.

20. The method of claim 17, wherein the step of determining the error further includes the step of stopping the movement of the robot cleaner or reducing speed thereof when the error is occurred.