Moving distance sensing apparatus for robot cleaner and method therefor

• US 7,706,921 B2
• Filed: 03/23/2005
• Issued: 04/27/2010
• Est. Priority Date: 11/11/2004
• Status: Expired due to Fees

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Jung, Il-Kyun
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): Kiswanto; Nicholas
• Application Number:
  US11/086,746
• Publication Number:
  US 20060100741A1
• Time in Patent Office: 1,861 Days
• Field of Search: 700/247, 700/254, 700/258, 700/41, 700/43, 700/68, 702/104, 702/149, 702/158, 702/159, 702/97
• 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 plurality of long distance sensors, each configured to sense a distance with its own sensing area, wherein a sum of respective sensing areas of the long distance sensors corresponds to an entire sensing area of the robot cleaner;

a plurality of short distance sensors, mounted on the same sensing lines in one-to-one correspondence with the plurality of long distance sensors for the same directions, respectively, each configured to sense a distance with its own sensing area, wherein a sum of respective sensing areas of the short distance sensors corresponds to an entire sensing area of the robot cleaner; and

a microcomputer configured to determine a precise moving distance and a moving distance error based on distance information with respect to the sensing areas of the long distance sensors and the short distance sensors,

wherein as the robot cleaner gets close to or away from a predetermined cleaning path or an arbitrary path, the microcomputer compares a moving distance rate sensed by the long distance sensors with a moving distance rate sensed by the short distance sensors, and determines a moving distance error depending on the compared result.

2. The sensing apparatus of claim 1, wherein the plurality of long distance sensors are ultrasonic sensors.

3. The sensing apparatus of claim 1, wherein the plurality of short distance sensors are infrared sensors.

4. The sensing apparatus of claim 1, wherein the long distance sensors are mounted on an outer circumferential surface of the robot cleaner at a uniform interval.

5. The sensing apparatus of claim 1, wherein the microcomputer compares the moving distance value sensed by the long distance sensors with the moving distance value sensed by the short distance sensors with respect to an area where the sensing area of the long distance sensors overlaps with the sensing area of the short distance sensors, and determines a moving distance error based on the compared result.

19. The sensing apparatus of claim 1, wherein the plurality of long distance sensors are vertically spaced from the plurality of short distance sensors.

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

a plurality of ultrasonic sensors mounted on an outer circumferential surface of the robot cleaner at a uniform interval and each configured to sense a distance with its own sensing area, wherein a sum of the respective sensing areas of the ultrasonic sensors corresponds to an entire sensing area of the robot cleaner;

a plurality of infrared sensors mounted on the same sensing lines in one-to-one correspondence with the plurality of ultrasonic sensors for the same direction, respectively, and each configured to sense a distance with its own sensing area, wherein the sum of the respective sensing areas of the infrared sensors corresponds to an entire sensing area of the robot cleaner; and

a microcomputer configured to determine a precise moving distance and a moving distance error based on distance information with respect to the sensing areas of the ultrasonic sensors and the infrared sensors,

wherein if the moving distance of a long distance sensed by the ultrasonic sensors and the moving distance of a short distance sensed by the infrared sensors 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 microcomputer determines that an error has occurred.

7. The sensing apparatus of claim 6, wherein the micro-computer directly compares the moving distance value sensed by the ultrasonic sensors with the moving distance value sensed by the infrared sensors with respect to an area where the moving distance sensed by the ultrasonic sensors overlaps with the moving distance sensed by the infrared sensors, and determines the moving distance error on the basis of the compared result.

8. The sensing apparatus of claim 6, wherein the microcomputer carries out a command to stop a movement of the robot cleaner or reduce its moving speed in case of error occurrence.

9. The sensing apparatus of claim 6, wherein when a decreasing rate with respect to the moving distance sensed by the ultrasonic sensors is coherent to a decreasing rate with respect to the moving distance sensed by the infrared sensors as the robot cleaner gets close to a specific object while moving along a predetermined cleaning path, the microcomputer determines the moving distance value of the robot cleaner as a precise value.

10. The sensing apparatus of claim 6, wherein when an increasing rate with respect to the moving distance sensed by the ultrasonic sensors is coherent to an increasing rate with respect to the moving distance sensed by the infrared sensors as the robot cleaner gets close to a specific object while moving along a predetermined cleaning path, the microcomputer determines the moving distance value of the robot cleaner as a precise value.

11. A method for sensing a moving distance of a robot cleaner, the method comprising:

sensing a moving distance based on distance information with respect to sensing areas of a plurality of long distance sensors and short distance sensors while the robot cleaner moves,

wherein the plurality of short distance sensors are mounted on the same sensing lines in one-to-one correspondence with the plurality of long distance sensors for the same directions, respectively,

wherein each sensor is configured to sense a moving distance with its own sensing area and wherein the sum of the respective sensing areas corresponds to an entire sensing area of the robot cleaner;

calculating a decreasing rate or an increasing rate for the moving distance sensed by respective long and short distance 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.

12. The method of claim 11, wherein the plurality of long distance sensors are ultrasonic sensors and the plurality of short distance sensors are infrared sensors.

13. The method of claim 11, further comprising stopping a movement of the robot cleaner or reducing speed thereof, in case of an error occurring due to inequality of the decreasing rate or the increasing rate thereof.

14. The method of claim 11, further comprising directly comparing the moving distance value sensed by the long distance sensors with the moving distance value sensed by the short distance sensors with respect to the area where an area sensed by the long distance sensors overlaps with an area sensed by the short distance sensors, and then determining the moving distance error on the basis of the compared result.

15. A method for sensing a moving distance, the method comprising:

setting a plurality of long distance sensors and short distance sensors in a body of the robot cleaner,

wherein the plurality of short distance sensors are mounted on the same sensing lines in one-to-one correspondence with the plurality of long distance sensors for the same directions, respectively,

wherein the long distance sensors and the short distance sensors have different sensing methods and each sensor is configured to sense a distance with its own sensing area,

wherein the sum of the respective sensing areas corresponds to an entire sensing area of the robot cleaner;

sensing moving distances using the long distance sensors and the short distance sensors simultaneously, and then calculating decreasing rates or increasing rates with respect to the sensed 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.

16. The method of claim 15, wherein the step of calculating the decreasing rates or the increasing rates includes:

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.

17. The method of claim 15, wherein the step of calculating the decreasing rates or the increasing rates includes:

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 sensors to calculate the short distance increasing rate according to a movement of the robot cleaner, and sensing a long distance by the long distance sensors to calculate the long distance increasing rate according to the movement of the robot cleaner.

18. The method of claim 15, 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.