ROBOT CONFINEMENT

• US 20090254218A1
• Filed: 06/19/2009
• Published: 10/08/2009
• Est. Priority Date: 03/17/2006
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: JONES, JOSEPH L., BERGMAN, JOHN, SANDIN, PAUL E., GILBERT, DUANE L. JR., OZICK, DANIEL N., LEWIS, DAVID M. JR., COHEN, DAVID A., VU, CLARA, MAMMEN, JEFFREY W., PRENETA, JOSHUA B., CHAIAPPETTA, MARK J., DUBROVSKY, ZIVTHAN A., CAMPBELL, TONY L.
• Granted Patent: US 8,781,627 B2
• Time in Patent Office: Days
• US Class Current: 700/258
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2240/425 Temperature
• CPC Class Codes: B60L 2240/662 Temperature
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 2260/32 Auto pilot mode
• CPC Class Codes: B60L 2270/145 Structure borne vibrations
• CPC Class Codes: B60L 3/0023 Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 50/52 characterised by DC-motors
• CPC Class Codes: B60L 50/62 charged by low-power generators primarily intended to support the batteries, e.g. range extenders
• CPC Class Codes: B60L 50/66 Arrangements of batteries
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: G05D 1/0225 involving docking at a fixed facility, e.g. base station or loading bay parking aids B62D15/027
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93
• CPC Class Codes: G05D 1/0259 using magnetic or electromagnetic means
• CPC Class Codes: G05D 1/0261 using magnetic plots
• CPC Class Codes: G05D 1/0265 : using buried wires
• CPC Class Codes: G05D 1/028 : using a RF signal
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y10S 901/01 : Mobile robot
• CPC Class Codes: Y10S 901/09 : Closed loop, sensor feedback controls arm movement

Abstract

A robot lawmnower includes a body, a drive system carried by the body, at least one caster wheel supporting the body, a grass cutter carried by the body, a controller in communication with the drive system, and a bump sensor in communication with the controller. The controller is configured to maneuver the robot to turn in place and to redirect the robot in response to the bump sensor sensing contact with an obstacle. The drive system is configured to maneuver the robot across a lawn and includes differentially driven right and left drive wheels positioned rearward of a transverse center axis defined by the body. The at least one caster wheel is positioned substantially forward of the right and left drive wheels, and the grass cutter is positioned at least partially forward of the right and left drive wheels and at least partially behind the at least one caster wheel.

Claims

1. A robot lawnmower comprising:

a body;

a drive system carried by the body and configured to maneuver the robot across a lawn, the drive system comprising right and left drive wheels, the drive wheels being differentially driven;

at least one caster wheel supporting the body;

a grass cutter carried by the body;

a controller in communication with the drive system and configured to maneuver the robot to turn in place; and

a bump sensor in communication with the controller, the controller being configured to redirect the robot in response to the bump sensor sensing contact with an obstacle;

wherein the drive wheels are positioned rearward of a transverse center axis defined by the body, the at least one caster wheel is positioned substantially forward of the right and left drive wheels, and the grass cutter is positioned at least partially forward of the right and left drive wheels and at least partially behind the at least one caster wheel.

2. The robot lawnmower of claim 1, further comprising a cutter motor coupled to the grass cutter and positioned substantially in between the right and left drive wheels.

3. The robot lawnmower of claim 2, further comprising a clutch configured to engage the grass cutter with the cutter motor.

4. The robot lawnmower of claim 1, wherein the bump sensor comprises at least one displacement sensor positioned along the body to measure impact directionality, the drive system being configured to redirect the robot in response to the impact directionality.

5. The robot lawnmower of claim 1, further comprising at least one tilt sensor carried by the body and configured to sense a tilt angle of the robot, wherein the grass cutter halts operation upon the tilt sensor sensing a maximum tilt angle.

6. The robot lawnmower of claim 5, wherein the drive system is configured to stop maneuvering the robot in response to the tilt sensor sensing the maximum tilt angle.

7. The robot lawnmower of claim 1, further comprising a rain sensor carried by the body and configured to sense rain, the drive system configured to redirect the robot toward a home base in response to the rain sensor sensing rain.

8. The robot lawnmower of claim 1, further comprising a user interface disposed on the body and positioned substantially along an outer surface of the body.

9. The robot lawnmower of claim 1, wherein the body defines a substantially tombstone-shaped profile.

10. The robot lawnmower of claim 1, wherein the grass cutter comprises a rotary blade.

11. The robot lawnmower of claim 1, wherein a longitudinal center axis defined by the grass cutter is offset from a longitudinal center axis defined by the body.

12. The robot lawnmower of claim 1, wherein the turning center of the robot is substantially between the drive wheels along a longitudinal center axis defined by the body.

13. The robot lawnmower of claim 1, further comprising a motor gear box assembly carried by the body and positioned substantially between the right and left drive wheels.

14. The robot lawnmower of claim 1, further comprising a battery carried by the body positioned substantially between the right and left drive wheels.

15. An autonomous coverage robot system comprising:

an active boundary responder comprising a wire powered with a modulated current, the active boundary responder configured for placement along at least a portion of a perimeter of a property;

an autonomous coverage robot comprising;

a body;

a drive system carried by the body and configured to maneuver the robot across the property interior, the drive system comprising right and left differentially driven drive wheels, the drive wheels being positioned rearward of a transverse center axis defined by the body;

at least one caster supporting the body and positioned substantially forward of the right and left drive wheels;

a grass cutter carried by the body, the grass cutter positioned substantially forward of the right and left drive wheels and substantially behind the at least one caster;

a controller in communication with the drive system configured to maneuver the robot to turn in place; and

a boundary responder detection system in communication with the controller and configured to detect the active boundary responder, the controller being configured to redirect the robot in response to the boundary responder detection system detecting the active boundary responder.

16. The autonomous coverage robot system of claim 15, further comprising a bump sensor in communication with the controller, the controller being configured to redirect the robot in response to the bump sensor sensing contact with an obstacle.

17. The autonomous coverage robot system of claim 15, further comprising a battery carried by the body and positioned substantially between the drive wheels.

18. The autonomous coverage robot system of claim 17, further comprising a home base including a charging circuit for the battery, the controller being configured to return the robot to the home base in response to a low charge remaining in the battery.

19. The autonomous coverage robot system of claim 18, further comprising a rain sensor carried by the body and configured to sense rain, the controller being configured to return the robot to the home base in response to the rain sensor sensing rain.

20. A method of navigating a property with an autonomous coverage robot, the method comprising:

placing an active boundary responder along at least a portion of a perimeter of the property;

powering the active boundary responder with an electrical voltage; and

placing the robot within the property, the robot comprising;

a body;

a drive system carried by the body and configured to maneuver the robot across the property interior, the drive system comprising right and left differentially driven drive wheels, the drive wheels being positioned rearward of a transverse center axis defined by the body;

at least one caster supporting the body and positioned substantially forward of the right and left drive wheels;

a grass cutter carried by the body, the grass cutter positioned substantially forward of the right and left drive wheels and substantially behind the at least one caster;

a controller in communication with the drive system configured to maneuver the robot to turn in place; and

a boundary responder detection system in communication with the controller and configured to detect the active boundary responder, the controller being configured to redirect the robot in response to the boundary responder detection system detecting the active boundary responder.

permitting the robot to navigate the property while the controller redirects the robot, in response to the boundary responder detection system encountering the active boundary responder, to keep the robot within the property.

21. A robot lawmnower comprising:

a body;

a drive system carried by the body and configured to maneuver the robot across a lawn;

a grass cutter carried by the body; and

at least one water content sensor carried by the body and configured to sense water content of a surface, the drive system configured to redirect the robot in response to the sensor sensing water content indicative of a non-grass surface.

22. The robot lawmnower of claim 21, wherein the drive system comprises right and left sets of forward and rear drive wheels, each set of drive wheels being disposed on a corresponding side of the body and differentially driven with respect to each other.

23. The robot lawnmower of claim 22, wherein the forward and rear drive wheels are positioned forward and rearward, respectively, of a transverse center axis defined by the body.

24. The robot lawnmower of claim 22, further comprising a stasis detector carried by the body, the stasis detector configured to measure drive torque applied to at least one of the drive wheels, wherein the drive system is configured to redirect the robot upon the stasis detector measuring a maximum drive torque.

25. The robot lawnmower of claim 22, further comprising a stasis detector carried by the body, the stasis detector configured to measure an electric drive current delivered to at least one of the drive wheels, wherein the drive system is configured to redirect the robot upon the stasis detector measuring a maximum electric current.

26. The robot lawnmower of claim 22, further comprising a battery carried by the body and positioned substantially between the right and left sets of forward and rear drive wheels.

27. The robot lawnmower of claim 26, wherein the battery is configured to power a DC motor.

28. The robot lawnmower of claim 21, further comprising a controller in communication with the drive system, the controller configured to maneuver the robot lawmnower to turn in place.

29. The robot lawnmower of claim 21, wherein the water content sensor includes a passive sensor.

30. The robot lawnmower of claim 29, wherein the passive sensor includes a first and a second electrically conductive projection extending substantially downwardly from the body, the first and second projections configured to form an electric circuit with moist grass contacting the first and second projections.

31. The robot lawnmower of claim 21, further comprising a tilt sensor carried by the body, the tilt sensor configured to sense a tilt angle of the body.

32. The robot lawnmower of claim 21, further comprising a stasis detector carried by the body and configured to measure a motor load of the grass cutter.

33. The robot lawnmower of claim 21, wherein the grass cutter comprises a rotary cutter.

34. The robot lawnmower of claim 21, wherein the grass cutter is vertically movable relative to the body to allow adjustment of a cut height of the grass cutter.

35. A robot lawnmower comprising:

a body;

a drive system carried by the body and configured to maneuver the robot across a lawn, the drive system comprising right and left sets of forward and rear drive wheels, each set of drive wheels being disposed on a corresponding side of the body and differentially driven with respect to each other;

a grass cutter carried by the body, the grass cutter arranged substantially between the right and left sets of drive wheels; and

at least one battery carried by the body, the battery positioned substantially between the rear wheels of the right and left sets of drive wheels.

36. The robot lawnmower of claim 35, wherein the robot lawnmower defines a primary turning center between the first and second set of drive wheels, substantially along a longitudinal axis defined by the body.

37. A robot lawnmower system comprising:

a charging circuit configured to releasably engage a battery, the charging circuit operable to charge the battery by converting AC current to DC current and delivering DC current to the battery while the battery is engaged to the charging circuit; and

a robot lawnmower comprising;

a body configured to carry the battery;

a drive system carried by the body and configured to maneuver the robot across a lawn;

a grass cutter carried by the body; and

a water content sensor carried by the body and configured to sense water content of a surface, the drive system configured to redirect the robot in response to the sensor sensing water content indicative of a non-grass surface.

38. A method of navigating a property with a robot lawnmower, the method comprising:

placing the robot within the property, the robot comprising;

a body;

a battery carried by the body;

a drive system carried by the body and configured to maneuver the robot across a lawn;

a grass cutter carried by the body; and

a water content sensor carried by the body and configured to sense water content of a surface, the drive system configured to redirect the robot in response to the sensor sensing water content indicative of a non-grass surface;

permitting the robot to navigate the property while the drive system redirects the robot in response to the sensor sensing water content indicative of a non-grass surface to keep the robot on a grass surface within the property.

39. The method of claim 38, further comprising periodically connecting the battery to a recharging circuit.

40. The method of claim 38, wherein periodically connecting the battery to a recharging circuit includes manually connecting the battery to the recharging circuit.

41. A robot lawnmower comprising:

a body;

a drive system carried by the body and configured to maneuver the robot across a lawn;

a grass cutter carried by the body;

a tilt sensor carried by the body, the tilt sensor configured to sense a tilt angle of the body; and

a wheel drop sensor carried by the body, the wheel drop sensor configured to sense when at least a portion of the drive system enters an extended position, the robot lawnmower configured to cease an operating behavior upon detection of a signal from the tilt sensor and a signal from the wheel drop sensor.

42. The robot lawnmower of claim 41, wherein the tilt sensor comprises an accelerometer.

43. The robot lawnmower of claim 41, wherein the tilt sensor is configured to compare a measured robot inclination with a known value.

44. The robot lawnmower of claim 41, wherein the tilt sensor is configured to generate a signal above a maximum tilt angle of the robot lawnmower.

45. The robot lawnmower of claim 41, wherein the wheel drop sensor is configured to generate a signal after being triggered for a specified amount of time.

46. The robot lawnmower of claim 41, wherein the drive system comprises at least one wheel biased to drop, the wheel drop sensor configured to trigger when the at least one wheel drops to a position indicative of loss of contact with the surface.