ROBOT CLEANER AND CONTROL METHOD THEREOF

• US 20140214205A1
• Filed: 01/27/2014
• Published: 07/31/2014
• Est. Priority Date: 01/29/2013
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Original Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Inventors: KIM, Shin, KWON, Joonhyung, CHUN, Ji Won
• Granted Patent: US 9,399,284 B2
• Time in Patent Office: Days
• US Class Current: 700/258
• 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 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: A47L 2201/06 Control of the cleaning action for autonomous devices; Automatic detection of the surface condition before, during or after cleaning
• CPC Class Codes: A47L 9/2826 the condition of the floor
• CPC Class Codes: B25J 9/0003 Home robots, i.e. small robots for domestic use
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/2632 flat
• CPC Class Codes: G01N 29/11 by measuring attenuation of acoustic waves
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93

Abstract

A robot cleaner includes a main body, a traveling unit installed in the main body, to move the main body, an ultrasonic sensor to emit an oscillation wave, to receive a reflection wave reflected from an object surface, and to output vibration generated by the oscillation wave and vibration generated by the reception of the reflection wave as an electrical signal, a waveform analyzer to calculate a generation time period of the electrical signal output from the ultrasonic sensor, and a controller to determine information about the object surface based on the calculated generation time period of the electrical signal, and to control movement of the traveling unit based on the information about the object surface.

Claims

1. A robot cleaner comprising:

a traveling unit to move the robot cleaner;

an ultrasonic sensor to emit an oscillation wave, to receive a reflection wave reflected from an object surface, and to output vibration generated by the oscillation wave and vibration generated by the reception of the reflection wave as an electrical signal; and

a controller to determine information about the object surface based on the electrical signal output from the ultrasonic sensor, and to control movement of the traveling unit based on the information about the object surface.

2. The robot cleaner according to claim 1, wherein the electrical signal is an electrical signal for a composite wave appearing when the oscillation wave overlaps the reflection wave, or an electrical signal for a composite wave appearing when an aftershock generated by inertia of the oscillation wave overlaps the reflection wave.

3. The robot cleaner according to claim 2, further comprising a waveform analyzer to calculate a waveform length of the composite wave based on the electrical signal of the composite wave,

wherein the controller compares the waveform length of the composite wave to a reference waveform length to determine the information about the object surface.

4. The robot cleaner according to claim 2, wherein the controller calculates an average amplitude of the composite wave based on the electrical signal of the composite wave, and determines the information about the object surface based on the average amplitude of the composite wave.

5. The robot cleaner according to claim 4, further comprising an Analog-to-Digital (AD) converter converting the electrical signal of the composite wave into a digital signal,

wherein the controller calculates the average amplitude of the composite wave using the digital signal.

6. The robot cleaner according to claim 4, wherein the controller calculates a tail length, which is a signal having a value smaller than the average amplitude in the electrical signal, and determines the information about the object surface based on the tail length.

7. The robot cleaner according to claim 4, wherein the controller calculates an average deviation of the composite wave using the average amplitude of the composite wave, and determines the information about the object surface using the calculated average deviation of the composite wave.

8. The robot cleaner according to claim 1, wherein the controller controls a cleaning mode based on the information about the object surface.

9. The robot cleaner according to claim 1, wherein the information about the object surface includes one or more of information about a material of the object, information about whether or not the object has been contaminated, and information about whether or not an empty space exists, and

wherein if it is determined that the material of the object is a soft material, that the object has been contaminated, or that an empty space exists, the controller controls avoidance traveling.

10. The robot cleaner according to claim 1, wherein the ultrasonic sensor has a closed structure.

11. The robot cleaner according to claim 3, further comprising another ultrasonic sensor,

wherein a distance between the other ultrasonic sensor and the object surface is different from a distance between the ultrasonic sensor and the object surface.

12. The robot cleaner according to claim 11, wherein the ultrasonic sensor and the other ultrasonic sensor are disposed at different distances from the object surface to respectively detect composite waves in which different kinds of interferences occur when a reflection wave is reflected from an object surface made of the same material.

13. The robot cleaner according to claim 12, wherein the waveform analyzer calculates a first waveform length of a first electrical signal output from the ultrasonic sensor, and a second waveform length of a second electrical signal output from the other ultrasonic sensor, and

wherein the controller determines the information about the object surface based on the first waveform length and the second waveform length.

14. The robot cleaner according to claim 13, wherein the waveform analyzer analyzes a first kind of interference of a composite wave in the first electrical signal and a second kind of interference of a composite wave in the second electrical signal, and

wherein the controller determines a material of the object surface based on the first kind of interference and the second kind of interference.

15. The robot cleaner according to claim 1, further comprising a waveform analyzer to detect and analyze feature points from the electrical signal of the composite wave,

wherein the controller determines the information about the object surface based on the result of the analysis of the feature points.

16. The robot cleaner according to claim 15, wherein the feature points correspond to a first time at which the composite wave starts to attenuate and a second time at which the attenuation of the composite wave terminates.

17. The robot cleaner according to claim 16, wherein the waveform analyzer further detects a gradient at which the composite wave attenuates between the first time and the second time, and

wherein the controller determines the information about the object surface based on at least one of the first time, the second time, and the gradient.

18. The robot cleaner according to claim 16, wherein the waveform analyzer further detects a maintenance time period from a time at which the reflection wave is received to the first time, and

wherein the controller determines the information about the object surface based on the maintenance time period.

19. The robot cleaner according to claim 15, wherein the information about the object surface includes information about a hardness of the object surface and whether the object surface has been contaminated, and

wherein if it is determined that the object surface is soft or that the object surface has been contaminated, the controller controls avoidance traveling.

20. The robot cleaner according to claim 16, wherein the waveform analyzer detects a type of interference of the composite wave, and

wherein the controller determines whether the type of interference of the detected composite wave is a constructive interference or a destructive interference to determine whether a material of the object surface is a hard material or a soft material.

21. The robot cleaner according to claim 1, further comprising a waveform analyzer to detect and analyze at least one wave among an oscillation wave, a reflection wave, and an echo wave from the electrical signal,

wherein the controller determines the information about the object surface based on information about the at least one wave among the oscillation wave, the reflection wave, and the echo wave.

22. The robot cleaner according to claim 21, wherein the controller determines the information about the object surface based on an intensity of the reflection wave.

23. The robot cleaner according to claim 21, wherein the controller determines the information about the object surface based on a number of echo waves.

24. The robot cleaner according to claim 21, wherein the waveform analyzer detects a first attenuation rate between the reflection wave and the echo wave and a second attenuation rate between a plurality of echo waves, and

wherein the controller determines the information about the object surface based on at least one attenuation rate of the first attenuation rate and the second attenuation rate.

25. A method of controlling a robot cleaner, the method comprising:

driving an ultrasonic sensor to emit an oscillation wave;

receiving a reflection wave reflected from an object surface by way of the ultrasonic sensor;

detecting an electrical signal when vibration generated by the oscillation wave and vibration generated by the reflection wave are output as the electrical signal from the ultrasonic sensor;

determining information about the object surface based on the detected electrical signal; and

controlling movement of a traveling unit of the robot cleaner based on the information about the object surface.

26. The method according to claim 25, wherein the determining of the information about the object surface based on the electrical signal comprises:

converting the electrical signal into a digital signal;

calculating an average amplitude of each of the oscillation wave, the composite wave, and the reflection wave using the digital signal; and

comparing the average amplitude to reference average amplitudes according to pre-stored information about various object surfaces to determine the information about the object surface.

27. The method according to claim 26, wherein the composite wave is a composite wave appearing when an aftershock generated by the emitting of the oscillation wave overlaps the reflection wave, or a composite wave appearing when the oscillation wave overlaps the reflection wave and the aftershock overlaps the reflection wave.

28. The method according to claim 26, wherein the determining of the information about the object surface based on the electrical signal further comprises:

calculating a tail length, which is a signal having a value smaller than the average amplitude; and

searching for a reference tail length range to which the detected tail length belongs in a plurality of reference tail length ranges according to the pre-set information about the object surface, and determining a material of the floor surface, whether the object surface has been contaminated, and whether an empty space exists.

29. The method according to claim 26, wherein the determining of the information about the object surface based on the electrical signal further comprises:

calculating an average deviation of the composite wave using the average amplitude; and

searching for a reference average deviation range to which the detected average deviation belongs in a plurality of reference average deviation ranges according to the pre-set information about the object surface, and determining a material of the floor surface, whether the object surface has been contaminated, and whether an empty space exists.

30. The method according to claim 25, wherein the controlling of the movement of the traveling unit comprises controlling avoidance traveling if it is determined that a material of the object surface is a soft material, that the object has been contaminated, or that an empty space exists.

31. The method according to claim 25, wherein the determining of the information about the object surface based on the electrical signal comprises:

detecting a first time at which the electrical signal starts to attenuate and a second time at which the attenuation of the electrical signal terminates, as feature points; and

comparing the detected feature points to a plurality of reference feature points according to pre-stored information about an object surface to determine the information about the object surface.

32. The method according to claim 31, wherein the determining of the information about the object surface based on the electrical signal further comprises:

detecting a gradient at which the electric signal attenuates between the first and second times, and a maintenance time period between a time at which the reflection wave is received and the first time; and

determining the information about the object surface based on at least one of the first time, the second time, the gradient, and the maintenance time period.

33. The method according to claim 25, wherein the determining of the information about the object surface based on the electrical signal comprises:

detecting a type of interference of a composite wave in the electrical signal; and

determining whether the type of interference of the detected composite wave is a constructive interference or a destructive interference to determine whether a material of the object surface is a hard material or a soft material.

34. The method according to claim 25, wherein the determining of the information about the object surface based on the electrical signal comprises:

detecting an intensity of a reflection wave in the electrical signal; and

comparing the intensity of the reflection wave to a plurality of reference intensities according to pre-set information about an object surface to determine the information about the object surface.

35. The method according to claim 25, wherein the determining of the information about the object surface based on the electrical signal further comprises:

detecting a number of echo waves in the electrical signal; and

comparing the detected number of echo waves to a plurality of reference numbers of echo waves according to pre-set information about an object surface to determine a material of the object surface.

36. The method according to claim 25, wherein the detecting of the electrical signal comprise:

emitting the oscillation wave, and receiving the oscillation wave and the composite wave, respectively, using a first ultrasonic sensor and a second ultrasonic sensor having different distances to the object surface;

detecting a first electrical signal for the oscillation wave, the reflection wave, and the composite wave using the first ultrasonic sensor; and

detecting a second electrical signal for the oscillation wave, the reflection wave, and the composite wave using the second ultrasonic sensor.

37. The method according to claim 36, further comprising:

calculating a first waveform length of the first electrical signal;

calculating a second waveform length of the second electrical signal;

comparing the first waveform length to the second waveform length to select a longer waveform length from among the first and second waveform lengths; and

comparing the selected waveform length to a reference waveform length to determine the information about the object surface.

38. The method according to claim 36, further comprising:

calculating a first waveform length of the first electrical signal;

calculating a second waveform length of the second electrical signal;

calculating a length difference between the first waveform length and the second waveform length; and

comparing the calculated length difference to a reference waveform length value to determine the information about the object surface.

39. A robot cleaner comprising:

a main body;

a traveling unit installed in the main body, to move the main body;

an ultrasonic sensor to emit an oscillation wave, to receive a reflection wave reflected from an object surface, and to output vibration generated by the oscillation wave and vibration generated by the reception of the reflection wave as an electrical signal;

a waveform analyzer to calculate a generation time period of the electrical signal output from the ultrasonic sensor; and

a controller to determine information about the object surface based on the calculated generation time period of the electrical signal, and to control movement of the traveling unit based on the information about the object surface.

40. The robot cleaner according to claim 39, wherein the waveform analyzer detects and analyzes at least one piece of information among a feature point of the electrical signal, an attenuation rate of the electrical signal, an average amplitude of the electrical signal, and an average deviation of the electrical signal, and

wherein the controller determines the information about the object surface based on the at least one piece of information analyzed by the waveform analyzer.

41. A robot cleaner comprising:

an ultrasonic sensor to emit an oscillation wave, to receive a reflection wave reflected from a floor, and to output a signal generated from the oscillation wave and from the reception of the reflection wave; and

a controller to determine information about the floor based on the electrical signal output from the ultrasonic sensor.

42. A robot cleaner configured to travel on a floor surface, the robot cleaner comprising:

a first ultrasonic sensor to acquire information about the floor surface, the first ultrasonic sensor being disposed on the robot cleaner a first distance above the floor;

a second ultrasonic sensor to acquire information about the floor surface, the second ultrasonic sensor being disposed on the robot cleaner a second distance above the floor surface,

wherein the first distance is different than the second difference.

43. The robot cleaner of claim 42, wherein a difference between the first distance and the second distance is predetermined to correspond to a quarter of a wavelength at which the first and second ultrasonic sensors emit radiation.