Debris sensor for cleaning apparatus

• US 7,288,912 B2
• Filed: 09/19/2006
• Issued: 10/30/2007
• Est. Priority Date: 01/28/2004
• Status: Expired due to Term

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Cohen, David A., Landry, Gregg W., Ozick, Daniel
• Primary Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US11/533,294
• Publication Number:
  US 20070069680A1
• Time in Patent Office: 406 Days
• Field of Search: 318/580, 318/568.12, 701/28, 153/19
• US Class Current: 318/580
• CPC Class Codes: A47L 11/4005 Arrangements of batteries or cells; Electric power supply arrangements
• CPC Class Codes: A47L 11/4008 Arrangements of switches, indicators or the like
• 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 11/4061 Steering means; Means for avoiding obstacles; Details related to the place where the driver is accommodated
• CPC Class Codes: A47L 11/4066 Propulsion of the whole machine
• 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 5/362 of the horizontal type, e.g. canister or sledge type
• CPC Class Codes: A47L 9/0466 Rotating tools
• CPC Class Codes: A47L 9/0488 Combinations or arrangements of several tools, e.g. edge cleaning tools
• CPC Class Codes: A47L 9/2805 Parameters or conditions being sensed
• CPC Class Codes: A47L 9/281 the amount or condition of incoming dirt or dust
• CPC Class Codes: A47L 9/2831 Motor parameters, e.g. motor load or speed
• CPC Class Codes: A47L 9/2842 Suction motors or blowers
• 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: A47L 9/2857 User input or output elements for control, e.g. buttons, switches or displays
• CPC Class Codes: A47L 9/2884 Details of arrangements of batteries or their installation
• CPC Class Codes: A47L 9/2889 Safety or protection devices or systems, e.g. for prevention of motor over-heating or for protection of the user
• CPC Class Codes: A47L 9/2894 Details related to signal transmission in suction cleaners
• CPC Class Codes: G05D 1/021 specially adapted to land vehicles
• CPC Class Codes: G05D 1/0227 : using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 1/0238 : using obstacle or wall sensors G05D1/0246 and G05D1/0289 take precedence; lidar systems designed for anti-collision purposes G01S17/93
• CPC Class Codes: G05D 1/0242 : using non-visible light signals, e.g. IR or UV signals
• 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
• CPC Class Codes: Y10S 901/01 : Mobile robot
• CPC Class Codes: Y10S 901/46 : Sensing device

Abstract

A piezoelectric debris sensor and associated signal processor responsive to debris strikes enable an autonomous or non-autonomous cleaning device to detect the presence of debris and in response, to select a behavioral mode, operational condition or pattern of movement, such as spot coverage or the like. Multiple sensor channels (e.g., left and right) can be used to enable the detection or generation of differential left/right debris signals and thereby, enable an autonomous device to steer in the direction of debris.

Claims

1. An autonomous cleaning apparatus, comprising:

a drive system operable to enable movement of the cleaning apparatus;

a controller in communication with the drive system, the controller including a processor operable to control the drive system to steer movement of the cleaning apparatus and provide at least one pattern of movement of the cleaning apparatus; and

a debris sensor responsive to debris impacts thereon for generating a debris signal indicating that the cleaning apparatus has encountered debris;

wherein the processor is responsive to the debris signal to steer movement of the cleaning apparatus into a spiraling pattern of movement having a changing turn radius, to substantially immediately cover an area containing debris corresponding to the debris signal.

2. The apparatus of claim 1 wherein the pattern of movement comprises spot coverage of an area containing debris.

3. The apparatus of claim 1 wherein the piezoelectric element comprises a flexible piezoelectric film.

4. The apparatus of claim 1 wherein the processor is further operable to steer the cleaning apparatus such that a subsequent pattern of movement covers an area containing debris.

5. The apparatus of claim 4 wherein the subsequent pattern of movement comprises the cleaning apparatus turning left.

6. The apparatus of cairn 4 wherein the subsequent pattern of movement comprises the cleaning apparatus turning right.

7. An autonomous cleaning apparatus, comprising:

a drive system operable to enable movement of the cleaning apparatus;

a controller communication with the drive system, the controller including a processor operable to control the drive system to steer movement of the cleaning apparatus and provide at least one pattern of movement of the cleaning apparatus; and

a debris sensor responsive to debris impacts thereon for generating a debris signal indicating that the cleaning apparatus has encountered debris;

wherein the processor is responsive to the debris signal to select a spot coverage mode front among predetermined operative modes of the cleaning apparatus, the spot coverage mode composing steering movement of the cleaning apparatus to substantially immediately cover an area containing debris corresponding to the debris signal.

8. The apparatus of claim 7 wherein selection of an operative mode comprises selecting a pattern of movement.

9. The apparatus of claim 8 wherein the pattern of movement comprises spot coverage of an area containing debris.

10. The apparatus of claim 8 wherein the spot coverage mode comprises steering the cleaning apparatus in a spiral pattern toward an area containing debris corresponding to the debris signal.

11. The apparatus of claim 7 wherein the debris sensor comprises spaced-apart first and second debris sensing elements respectively operable to generate first and second debris signals;

and

wherein the processor is responsive to the first second debris signals to select a pattern of movement.

12. The apparatus of claim 11 further wherein the processor is responsive to differences in the first and second debris signals to steer the cleaning apparatus in a direction of debris.

13. The apparatus of claim 7 wherein the debris sensor comprises a piezoelectric sensor element located proximate a cleaning pathway of the cleaning apparatus and responsive to a debris impact to generate a signal indicative of such impact.

14. The apparatus of claim 13 wherein the debris sensor comprises a single piezoelectric element.

15. A cleaning apparatus comprising:

a cleaning pathway for transporting debris;

a piezoelectric sensor located proximate to the cleaning pathway and responsive to a debris impact thereon to generate a debris signal indicative of such impact; and

a processor responsive to the debris signal indicative of a debris impact thereon to cause the cleaning apparatus to enter a substantially spiral movement mode having a reduced movement speed.

16. The apparatus of claim 15 wherein the processor is further responsive to the debris signal to change an operative mode that comprises illuminating a user-perceptible indicator light.

17. The apparatus of claim 15 wherein the processor is further responsive to the debris signal to change an mode that comprises changing a power setting.

18. The apparatus of claim 15 wherein the piezoelectric sensor element comprises a flexible piezoelectric film having multiple electrically isolated sections.

19. A debris sensor for a cleaning apparatus, the debris sensor comprising:

a piezoelectric element located proximate to a cleaning pathway of the cleaning apparatus and responsive to a debris impact thereon to generate a first signal indicative of such impact; and

a processor operable to process the first signal to generate a second signal representative of a relative debris being encountered by the cleaning apparatus and to cause the cleaning apparatus to enter a substantially spiral movement mode having a reduced movement speed, in response to the second signal.

20. The sensor of claim 19 wherein the processor is further operable to process the first signal to generate a signal representative of a vector from a present location of the cleaning apparatus to an area containing debris.

21. The sensor of claim 19 wherein the processor is further operable, in response to the second signal, to change an operative mode of the cleaning apparatus.

22. The sensor of claim 21 wherein the change of operative mode comprises changing a power setting.

23. The sensor of claim 21 wherein the change of operative mode comprises illuminating a user-perceptible indicator light.

24. The sensor of claim 19 wherein:

the piezoelectric element is mounted proximate to the cleaning pathway by mounting elements, and

the mounting elements comprise at least one nounting screw and associated elastomer mounting grommet.

25. The sensor of claim 24 wherein the elastomer mounting grommet receives the mounting screw and provides vibration dampening for the piezoelectric element mounted proximate to the cleaning pathway by the mounting screw.

26. The sensor of claim 19 wherein the piezoelectric element comprises a flexible piezoelectric film.

27. A method of operating an autonomous cleaning apparatus, the method comprising:

steering movement of the cleaning apparatus in at least one pattern of movement of the cleaning apparatus;

generating, with a debris sensor responsive to debris impacts, a debris signal indicating that the cleaning apparatus has encountered debris; and

steering movement of the cleaning apparatus into a spiraling pattern of movement having a changing turn radius substantially immediately cover an area containing debris corresponding to the debris signal.

28. The method of claim 27 wherein the pattern of movement comprises spot coverage of an area containing debris.

29. A method of operating an autonomous cleaning apparatus, the method comprising:

steering movement to provide at least one pattern of movement of the cleaning apparatus;

generating, with a debris sensor responsive to debris impacts, a debris signal indicating that the cleaning apparatus has encountered debris; and

responding to the debris signal to select a spot coverage mode from among predetermined operative modes of the cleaning apparatus, the spot coverage mode comprising steering movement of the cleaning apparatus so that the cleaning apparatus substantially immediately covers a dirty area corresponding to the debris signal.

30. The method of claim 29 wherein the spot coverage mode comprises steering the cleaning apparatus in a spiraling pattern toward an area containing debris corresponding to the debris signal.

31. The method of claim 29 wherein the generating comprises generating first and second debris signals with spaced apart first and second debris sensors;

and

wherein the responding comprises responding to the first and second debris signals to select a pattern of movement.

32. The method of claim 31 further wherein the responding comprises responding to differences in the first and second debris signals to steer the cleaning apparatus in a direction of debris.

33. The method of claim 29 wherein the generating comprises generating a debris signal with a piezoelectric sensor clement located proximate a cleaning pathway of the cleaning apparatus and responsive to a debris impact.

34. A method of operating a cleaning apparatus, the method comprising:

generating, with a piezoelectric sensor located proximate to a cleaning pathway of the cleaning apparatus and responsive to a debits impact, a debris signal indicative of such impact; and

causing the cleaning apparatus to enter a substantially spiral movement mode having a reduced movement speed in response to the debris signal.

35. The method of claim 34 further comprising changing, in response to the debris signal, an operative mode that comprises illuminating a user-perceptible indicator light.

36. The method of claim 34 further comprising changing, in response to the debris signal, an operative mode that comprises changing a power setting.

37. The method of claim 34 wherein the piezoelectric sensor element comprises a flexible piezoelectric film having multiple electrically isolated sections.

38. The method of claim 34 wherein the piezoelectric element comprises a flexible piezoelectric film.

39. A method of operating a cleaning apparatus, the method comprising:

generating, with a piezoelectric element located proximate to a cleaning pathway of the cleaning apparatus and responsive to a debris impact thereon, a first signal indicative of such impact;

processing the first signal to generate a second signal representative of a relative quantity of debris being encountered by the cleaning apparatus; and

in response to the second signal, entering a substantially spiral movement mode having a reduced movement speed.

40. The method of claim 39 further comprising processing the first signal to generate a signal representative of a vector from a present location of the cleaning apparatus to an area containing debris.

41. The method of claim 39 further comprising changing, in response to the second signal, an operative mode of the cleaning apparatus.

42. The method of claim 41 wherein changing operative mode comprises changing a power setting.

43. The method of claim 41 wherein changing operative mode comprises illuminating a user-perceptible indicator light.

44. The method of claim 39 further comprising:

mounting the piezoelectric element proximate to the cleaning pathway using at least one mounting screw and associated elastomer mounting grommet.

45. The method of claim 44 wherein the elastomer mounting grommet receives the mounting screw and provides vibration dampening for the piezoelectric element mounted proximate to the cleaning pathway by the mounting screw.

46. The method of claim 39 wherein the piezoelectric element comprises a flexible piezoelectric film.

47. A cleaning apparatus, comprising:

a debris sensor operable to generate a debris pulse and that includes a combination of a metal disk and a piezoelectric material responsive to impact on the disk;

a mounting system including an elastomer pad and a plurality of elastomer grommets for providing vibration dampening to the debris sensor, the elastomer pads and grommets mounting the metal disk in place such that the surface area of the metal disk between the grommets is not clamped; and

a signal processing circuit connected to the debris sensor and including;

a filter circuit that removes acoustic noise and radio interference from the debris pulse,

a comparator circuit that compares the debris pulse to a background reference level to verify a debris impact, and

an output circuit that outputs a debris strike event signal corresponding to the debris pulse.

48. The apparatus of claim 47 wherein the metal disk comprises a brass disk.

49. The apparatus of claim 47 wherein the piezoelectric material comprises a flexible piezoelectric film.

50. The apparatus of claim 47 wherein the comparator circuit detects a debris impact when the debris pulse has a substantially higher amplitude than the background reference level.

51. The apparatus of claim 47 wherein the background reference level comprises a changing average of instantaneous peak debris pulse values.

52. A method of operating a cleaning apparatus, comprising;

sensing the impact of debris with a debris sensor;

generating a debris pulse that corresponds to the impact of debits on a debris sensor;

mounting a debris sensor so that vibrations are dampened; and

processing the signal from the debris sensor, comprising;

filtering acoustic noise and radio interference from the debris pulse,

comparing the debris pulse to a background reference level to verify a debris impact, and

outputting a debris strike event signal that corresponds to the debris pulse.

53. The method of claim 52 wherein sensing includes sensing with a piezoelectric material mounted to a metal disk and responsive to debris impact on the disk.

54. The method of claim 53 wherein sensing includes sensing with a flexible piezoelectric film.

55. The method of claim 53 wherein comparing the debris pulse to the background reference level includes detecting when the debris pulse has a substantially higher amplitude than the background reference level.

56. An autonomous cleaning apparatus, comprising:

a drive system operable to enable movement of the cleaning apparatus;

a controller in communication with the drive system, the controller including a processor operable to control the drive system to steer movement of the cleaning apparatus and provide at least one pattern of movement of the cleaning apparatus; and

a debris sensor responsive to debris impacts thereon for generating a debris signal indicating that the cleaning apparatus has encountered debris;

wherein the processor responds to the debris signal by causing a spot cleaning pattern of movement in an area in which the autonomous cleaning apparatus was operating when the debris signal was generated.

57. An autonomous cleaning apparatus composing:

a drive system operable to enable movement of the cleaning apparatus;

a controller in communication with the drive system, the controller including a processor operable to control the drive system to steer movement of the cleaning apparatus and provide at least one pattern of movement of the cleaning apparatus; and

a debris sensor responsive to debris impacts thereon for generating a debris signal indicating that the cleaning apparatus has encountered debris;

wherein the debris signals are processed by the processor to signal the autonomous cleaning apparatus to substantially immediately steer to a debris-containing area in which the autonomous cleaning apparatus was operating when the debris signals were generated.