DETECTING ROBOT STASIS

• US 20130310978A1
• Filed: 02/26/2013
• Published: 11/21/2013
• Est. Priority Date: 05/31/2006
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: OZICK, Daniel N., Gilbert, Duane L. Jr.
• Granted Patent: US 9,317,038 B2
• Time in Patent Office: Days
• US Class Current: 700/258
• CPC Class Codes: A47L 2201/00 Robotic cleaning machines, i.e. with automatic control of the travelling movement or the cleaning operation
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: A47L 9/009 Carrying-vehicles; Arrangements of trollies or wheels; Means for avoiding mechanical obstacles
• CPC Class Codes: A47L 9/2826 the condition of the floor
• CPC Class Codes: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16

Abstract

A coverage robot includes a drive configured to maneuver the robot as directed by a controller, a stasis indication wheel rotatable about a first axis perpendicular to a direction of forward travel, and a suspension supporting the wheel. The stasis indication wheel defines a first reflective portion and a second reflective portion. The second reflective portion is substantially less reflective than the first reflective portion. The suspension permits movement of the wheel in a direction other than rotation about the first axis. A signal emitter is disposed remotely from the wheel and positioned to direct a signal that sequentially is intercepted by the first and second reflective portions of the wheel. A signal receiver is positioned to receive the reflected signal by the rotating wheel. Communication between the emitter and the receiver is affected by rolling transitions between the first and second reflective portions during permitted movement of the wheel.

Claims

1-21. -21. (canceled)

22. A coverage robot comprising:

a body;

a wheeled-drive that maneuvers the body over a surface according to drive commands from a controller in communication with the drive;

a first stasis sensor carried on the body, and responsive to surface-relative movement of the body;

a second stasis sensor carried separately on the body from the first stasis sensor, and responsive to surface-relative movement of the body,

wherein the controller is configured to;

receive sensory output from each of the first and second stasis sensors; and

determine whether the body is moving relative to the surface as a function of the drive commands and sensory output from at least one of the first and second stasis sensors.

23. The coverage robot of claim 22, wherein the controller is further configured to transition from the first stasis sensor to the second stasis sensor as a primary sensor.

24. The coverage robot of claim 23, wherein the controller comprises a transition algorithm to cause a unitary transition from the first stasis sensor to the second stasis sensor.

25. The coverage robot of claim 23, wherein the controller comprises a transition algorithm to cause a gradual transition from the first stasis sensor to the second stasis sensor.

26. The coverage robot of claim 23, wherein the controller is further configured to determine when the efficacy of the sensory output from the first stasis sensor has degraded below a predetermined threshold, and to initiate the transition in response to the degradation determination.

27. The coverage robot of claim 22, wherein the controller is further configured to integrate received sensory output from the first stasis sensor with sensory output from the second stasis sensor.

28. The coverage robot of claim 22, wherein at least one of the first and second stasis sensors comprises:

a rotating non-driven, stasis indication wheel; and

a non-contact wheel sensor defining an area of detection around the stasis indication wheel.

29. The coverage robot of claim 28, wherein the stasis indication wheel comprises a bi-colored wheel with one or more light sections and one or more dark sections, and wherein the wheel sensor comprises an optical sensor that detects transitions between light and dark sections as the stasis indication wheel spins.

30. The coverage robot of claim 29, wherein the one or more light sections of the stasis indication wheel reflect light of a first infrared wavelength and the one or more dark sections reflect light of a second infrared wavelength different from the first wavelength.

31. The coverage robot of claim 29, wherein the optical sensor comprises:

a signal emitter disposed remotely from the stasis indication wheel and positioned to direct a signal that sequentially is intercepted by the light and dark sections of the stasis indication wheel; and

a signal receiver positioned to receive the signal as reflected by the stasis indication wheel as the stasis indication wheel rotates with respect to the emitter.

32. The coverage robot of claim 28, wherein the stasis indication wheel comprises one or more magnetic sections and one or more non-magnetic sections, and wherein the wheel sensor is responsive to the magnetic sections.

33. The coverage robot of claim 28, wherein the stasis indication wheel comprises a load-bearing caster wheel.

34. The coverage robot of claim 28, wherein the stasis indication wheel comprises a hub and multiple spokes extending outwardly from the hub.

35. The coverage robot of claim 28, further comprising a drop wheel sensor arranged to detect vertical displacement of the stasis indication wheel.

36. The coverage robot of claim 28, further comprising a wheel housing carried by the body and shrouding the stasis indication wheel, the wheel housing defining an aperture in a top portion of the wheel housing, exposing the stasis indication wheel to the wheel sensor.

37. The coverage robot of claim 36, wherein the wheel housing is configured to minimize an entry of ambient light into the aperture of the housing.

38. The coverage robot of claim 28, wherein the stasis indication wheel is disposed adjacent a drive wheel.

39. The coverage robot of claim 22, wherein at least one of the first and second stasis sensor comprises a drive motor sensor monitoring a drive motor of the wheeled-drive.

40. The coverage robot of claim 39, wherein the drive motor sensor monitors a drive current drawn by the drive motor.

41. The coverage robot of claim 22, further comprising a cliff signal emitter and a cliff signal receiver, the cliff signal emitter aligned to emit a cliff detection signal onto a floor surface proximate the body, the cliff signal receiver configured to receive the cliff detection signal reflected from the floor surface;

wherein the cliff signal emitter and cliff signal receiver are arranged with respect to the floor surface such that communication between the cliff signal emitter and the cliff signal receiver is affected by vertical movement of the floor surface with respect to the body.