Mobile Robot

• US 20130226344A1
• Filed: 07/23/2012
• Published: 08/29/2013
• Est. Priority Date: 02/29/2012
• Status: Active Grant

• Current Assignee: Ava Robotics, Inc.
• Original Assignee: iRobot Corporation
• Inventors: Wong, Cheuk Wah, Rauhut, Eben, Halloran, Michael, Won, Chikyung, Chiappetta, Mark, Benson, Brian C., Lydon, Peter J., Rosenstein, Michael T., Shamlian, Steven V., Kearns, Justin H., Taka, Orjeta, Pack, Robert Todd, Farlow, Timothy S., Vicenti, Jasper Fourways
• Granted Patent: US 8,958,911 B2
• Time in Patent Office: Days
• US Class Current: 700/258
• CPC Class Codes: B25J 9/1694 characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G05D 1/0214 in accordance with safety or protection criteria, e.g. avoiding hazardous areas monitoring the location of vehicles within a certain area, e.g. forbidden or allowed areas, in traffic control systems for road vehicles G08G1/13
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: Y10S 901/01 Mobile robot
• CPC Class Codes: Y10S 901/09 Closed loop, sensor feedback controls arm movement
• CPC Class Codes: Y10S 901/46 Sensing device
• CPC Class Codes: Y10S 901/47 Optical

Abstract

A mobile robot including a robot body, a drive system supporting the robot body, and a controller in communication with the drive system. The robot also includes an actuator moving a portion of the robot body through a volume of space adjacent the mobile robot and a sensor pod in communication with the controller. The sensor pod includes a collar rotatably supported and having a curved wall formed at least partially as a surface of revolution about a vertical axis. The sensor pod also includes a volumetric point cloud sensor housed by the collar and observing the volume of space adjacent the robot from within the collar along an observation axis extending through the curved wall. A collar actuator rotates the collar and the volumetric point cloud sensor together about the collar axis.

Claims

1. A mobile robot comprising:

a robot body;

a drive system supporting the robot body and configured to maneuver the robot over a floor surface, the drive system having a forward drive direction;

a controller in communication with the drive system;

an actuator moving a portion of the robot body through a volume of space adjacent the mobile robot; and

a sensor pod in communication with the controller, the sensor pod comprising;

a collar rotatably supported by the robot body and having a curved wall formed at least partially as a surface of revolution about a vertical axis of rotation with respect to the floor surface;

a volumetric point cloud sensor housed by the collar and observing the volume of space adjacent the robot from within the collar along an observation axis extending through the curved wall, the volumetric point cloud sensor capturing three dimensional volumetric point clouds representative of obstacles within the observed volume of space; and

a collar actuator rotating the collar and the volumetric point cloud sensor together about the collar axis;

wherein all rotating portions of the volumetric point cloud sensor extend a lesser distance from the collar axis than an outermost point of the collar.

2. The mobile robot of claim 1, wherein the surface of revolution of the curved wall sweeps about 360 degrees about the collar axis to form a substantially complete perimeter of the collar.

3. The mobile robot of claim 1, wherein the collar actuator moves the collar both clockwise and counter clockwise about the collar axis of rotation.

4. The mobile robot of claim 1, wherein the sensor pod further comprises a shroud covering the rotating collar.

5. The mobile robot of claim 1, wherein the sensor pod comprises at least two volumetric point cloud sensors arranged to observe the volume of space adjacent the mobile robot from within the collar along different observation axes extending through the curved wall, each volumetric point cloud sensors capturing separate three dimensional volumetric point clouds of obstacles within the observed volume of space.

6. The mobile robot of claim 5, wherein the captured separate three dimensional volumetric point clouds are of non-overlapping sub-volumes within the observed volume of space.

7. The mobile robot of claim 5, wherein the observation axes of the at least two volumetric point cloud sensors are angled with respect to a plane normal to the collar axis to observe separate sub-volumes of the observed volume of space, the separate sub-volumes being displaced from one another along the collar axis by a distance greater than twice a diameter of the collar.

8. The mobile robot of claim 1, wherein the observation axis of the volumetric point cloud sensor is angled with respect to a plane normal to the collar axis to observe the volume of space adjacent the robot at a height along the collar axis that is greater than or equal to a diameter of the collar.

9. The mobile robot of claim 1, wherein the sensor pod comprises

a first volumetric point cloud sensor housed by the collar and observing a volume of space adjacent the sensor pod from within the collar along a first observation axis extending through the curved wall, the first volumetric point cloud sensor capturing three dimensional volumetric point clouds representative of obstacles within the observed volume of space;

and

a second volumetric point cloud sensor housed by the collar and observing the volume of space adjacent the sensor pod from within the collar along a second observation axis extending through the curved wall, the second observation axis different from the first observation axis, the second volumetric point cloud sensor capturing three dimensional volumetric point clouds representative of obstacles within the observed volume of space.

10. The mobile robot of claim 9, wherein the first observation axis is arranged at an angle θ

a with respect to a plane normal to the collar axis according to the following relationship;

θ

a=90°

−

(½

VFOV_a+tan<sup>−

1</sup>((W−

O_a)/H_a))

wherein VFOV_a is the vertical field of view of the first volumetric point cloud sensor, W is the width from a center vertical axis of the robot to a forward most edge of the robot, O_a is an offset distance of the first volumetric point cloud sensor form the collar axis, and H_a is a height of the first volumetric point cloud sensor with respect to the forward most edge of the robot.

11. The mobile robot of claim 9, wherein the second observation axis is arranged at an angle θ

c with respect to a plane normal to the collar axis according to the following relationship;

θ

c=90°

−

(½

VFOV_c+tan<sup>−

1</sup>((W−

O_c)/H_c))

wherein VFOV_C is the vertical field of view of the second volumetric point cloud sensor, W is the width from a center vertical axis of the robot to a forward most edge of the robot, O_c is an offset distance of the second volumetric point cloud sensor from the collar axis, and H_c is a height of the second volumetric point cloud sensor, W is the width from a center vertical axis of the robot to a forward most edge of the rowith respect to the forward most edge of the robot.

12. The mobile robot of claim 9, wherein the second volumetric point cloud sensor is offset from a center axis of the robot by an offset distance Ob equal to between about 0.8 and about 1.2 times an offset distance Ot between the first volumetric point cloud sensor and the center axis of the robot.

13. The mobile robot of claim 9, wherein the second volumetric point cloud sensor is offset from the center axis of the robot by an offset distance Ob substantially equal to an offset distance Ot between the first volumetric point cloud sensor and the center axis of the robot.

14. The mobile robot of claim 9, wherein the second observation axis is angled with respect to a plane normal to the collar axis by an angle of between about 45°

and about 65°

.

15. The mobile robot of claim 1, wherein the actuator moves, with at least one degree of freedom, a manipulator or an end effector extending from the robot body into the observed volume of space.

16. A mobile robot comprising:

a robot body;

a drive system supporting the robot body and configured to maneuver the robot over a floor surface, the drive system having a forward drive direction;

a controller in communication with the drive system;

an actuator moving a portion of the robot body through a volume of space adjacent the robot; and

a sensor pod in communication with the controller, the sensor pod comprising;

a collar rotatably supported by the robot body and having a curved wall formed at least partially as a surface of revolution about a vertical axis of rotation with respect to the floor surface;

an infrared range sensor housed by the collar and observing the volume of space adjacent the robot from within the collar along an observation axis extending through the curved wall, and infrared range sensor generating range value data representative of obstacles within the observed volume of space;

a presence sensor observing the volume of space adjacent the robot from within the collar along an axis parallel to the observation axis extending through the curved wall, the presence sensor generating presence value data representative of obstacles within the observed volume of space; and

a collar actuator rotating the collar, the infrared range sensor, and the presence sensor about the collar axis of rotation;

wherein all rotating portions of the infrared range sensor and the presence sensor extend a lesser distance from the collar axis of rotation than an outermost point of the collar.

17. The mobile robot of claim 16, wherein the infrared range sensor comprises at least one of a structured-light three dimensional scanner, a time of flight camera, a three-dimensional light detection and ranging sensor, or one or more triangulation ranging sensors.

18. The mobile robot of claim 16, wherein the presence sensor comprises at least one of a sonar sensor, ultrasonic ranging sensor, a radar sensor, a pyrometer, or a non-infrared sensor.

19. The mobile robot of claim 16, wherein the presence sensor senses at least one of acoustics, radiofrequency, visible wavelength light, or invisible wavelength light.

20. The mobile robot of claim 16, wherein the presence sensor detects a presence of an obstacle within a deadband of the infrared range sensor substantially immediately adjacent the infrared range sensor.

21. A sensor pod comprising:

a collar having a curved wall formed at least partially as a surface of revolution about a collar axis;

a first volumetric point cloud sensor housed by the collar and observing a volume of space adjacent the sensor pod from within the collar along a first observation axis extending through the curved wall, the first volumetric point cloud sensor capturing three dimensional volumetric point clouds representative of obstacles within the observed volume of space; and

a second volumetric point cloud sensor housed by the collar and observing the volume of space adjacent the sensor pod from within the collar along a second observation axis extending through the curved wall, the second observation axis different from the first observation axis, the second volumetric point cloud sensor capturing three dimensional volumetric point clouds representative of obstacles within the observed volume of space.

22. The sensor pod of claim 21, wherein the observation axis of the second volumetric point cloud sensor is angled with respect to a plane normal to the collar axis and with respect to the first observation axis to observe a sub-volume of the observed volume of space displaced along the collar axis by a distance greater than or equal to a diameter of the collar.

23. The sensor pod of claim 21, wherein the first observation axis is angled with respect to a plane normal to the collar axis by between about 45°

and about 65°

.

24. The sensor pod of claim 21, further comprising a collar actuator rotating the collar and the volumetric point cloud sensors together about the collar axis, wherein all rotating portions of the volumetric point cloud sensors extend a lesser distance from the collar axis of rotation than an outermost point of the collar.

25. The sensor pod of claim 21, wherein the surface of revolution of the curved wall sweeps about 360 degrees about the collar axis to form a substantially complete perimeter of the collar.

26. A sensor pod comprising:

a first interface;

a second interface spaced from the first interface;

a collar rotatably supported between the first and second interfaces, the collar having a curved wall formed at least partially as a surface of revolution about a collar axis;

a volumetric point cloud sensor housed by the collar and observing the volume of space adjacent the robot from within the collar along an observation axis extending through the curved wall, the volumetric point cloud sensor capturing three dimensional volumetric point clouds representative of obstacles within the observed volume of space;

a collar actuator rotating the collar and the volumetric point cloud sensor together about the collar axis with respect to the first and second interfaces; and

a channel extending through the collar from the first interface to the second interface.

27. The sensor pod of claim 26, wherein all rotating portions of the volumetric point cloud sensor extend a lesser distance from the collar axis than an outermost point of the collar.

28. The sensor pod of claim 26, wherein the wherein volumetric point cloud sensor comprises:

a speckle emitter emitting a speckle pattern of light onto a scene about the sensor pod; and

an imager receiving reflections of the speckle pattern from an object in the scene;

wherein a controller;

stores reference images of the speckle pattern as reflected off a reference object in the scene, the reference images captured at different distances from the reference object; and

compares at least one target image of the speckle pattern as reflected off a target object in the scene with the reference images for determining a distance of the reflecting surfaces of the target object.

29. The sensor pod of claim 28, wherein the wherein the controller determines a primary speckle pattern on the target object and computes at least one of a respective cross-correlation and a decorrelation between the primary speckle pattern and the speckle patterns of the reference images.

30. The sensor pod of claim 26, wherein the wherein the volumetric point cloud sensor emits light onto a scene about the sensor pod and captures images of the scene, the volumetric point cloud sensor determines a time-of-flight between emitting the light and receiving reflected light from the scene.

31. A sensor pod comprising:

a first interface;

a second interface spaced from the first interface;

a collar rotatably supported between the first and second interfaces, the collar having a curved wall formed at least partially as a surface of revolution about a collar axis;

a volumetric point cloud sensor housed by the collar and observing the volume of space adjacent the robot from within the collar along an observation axis extending through the curved wall, the volumetric point cloud sensor capturing three dimensional volumetric point clouds representative of obstacles within the observed volume of space;

a collar actuator rotating the collar and the volumetric point cloud sensor together about the collar axis with respect to the first and second interfaces; and

a cable carrier disposed adjacent the collar and connected to one of the interfaces, the cable carrier routing at least one cable to the rotatable collar.

32. The sensor pod of claim 31, wherein the cable carrier comprises:

an outer ring;

an inner ring disposed concentrically with the outer ring along the collar axis; and

a cable router having a first end connected to the outer ring and a second end connected to the inner ring.

33. The sensor pod of claim 32, wherein the cable router wraps around the inner ring in a spiral arrangement.

34. The sensor pod of claim 32, wherein the cable router folds upon itself with a reverse bending radius between the outer and inner rings.

35. The sensor pod of claim 34, wherein the cable carrier rotates within a range of +/−

450 degrees of rotation.

36. The sensor pod of claim 31, wherein the cable carrier comprises:

a first plate;

a second plate spaced from the first plate along the collar axis; and

a cable router having a first end connected to the first plate and a second end connected to the second plate, the cable router wrapping around the collar axis in a clockwise direction and folding upon itself to wrap around the collar axis in a counter clockwise direction.

37. The sensor pod of claim 36, wherein the cable carrier rotates within a range of +/−

7000 degrees of rotation.

38. The sensor pod of claim 36, wherein the cable carrier has a rotation speed up to 360 degrees per second.

39. The sensor pod of claim 31, wherein lengths of cables routed by the cable carrier are greater than or equal to three times a diameter of the collar.

40. The sensor pod of claim 31, wherein the cable carrier comprises interconnected links collectively maintaining a minimum bending radius of the at least one cable.

41. A mobile robot comprising:

a drive system having a forward drive direction;

a controller in communication with the drive system;

a first interface;

a second interface spaced from the first interface;

a collar rotatably supported between the first and second interfaces, the collar having a curved wall formed at least partially as a surface of revolution about a collar axis;

a volumetric point cloud imaging device housed by the collar and observing the volume of space adjacent the robot from within the collar along an observation axis extending through the curved wall, the volumetric point cloud imaging device capturing three dimensional volumetric point clouds representative of obstacles within the observed volume of space;

a collar actuator rotating the collar and the volumetric point cloud imaging device together about the collar axis with respect to the first and second interfaces; and

a dead zone sensor having a detection field arranged to detect an object in a volume of space undetectable by the volumetric point cloud imaging device;

wherein the controller receives point cloud signals from the imaging device and detection signals from the dead zone sensor and issues drive commands to the drive system based at least in part on the received point cloud and detection signals.

42. The mobile robot of claim 41, wherein the dead zone sensor comprises at least one of a volumetric point cloud imaging device, a sonar sensor, a camera, an ultrasonic sensor, LIDAR, LADAR, an optical sensor, or an infrared sensor.

43. The mobile robot of claim 41, wherein the detection field of the dead zone sensor envelopes a volume of space undetectable by the volumetric point cloud imaging device.

44. The mobile robot of claim 43, wherein the volume of space undetectable by the volumetric point cloud imaging device is defined by a first angle by a second angle and by a radius.

45. The mobile robot of claim 41, wherein the detection field of the dead zone sensor is arranged between the volumetric point cloud imaging device and a detection field of the volumetric point cloud imaging device.

46. The mobile robot of claim 41, wherein the dead zone sensor has a field of view extending at least 3 meters outward from the dead zone sensor.

47. The mobile robot of claim 41, further comprising an array of dead zone sensors with at least one dead zone sensor having its detection field arranged to detect an object in the volume of space undetectable by the volumetric point cloud imaging device, the array of dead zone sensors arranged with their fields of view along the forward drive direction or evenly disbursed about a vertical center axis defined by the robot.

48. The mobile robot of claim 41, wherein the imaging device emits light onto a scene about the robot and captures images of the scene along the drive direction of the robot, the images comprising at least one of (a) a three-dimensional depth image, (b) an active illumination image, or (c) an ambient illumination image;

wherein the controller determines a location of an object in the scene based on the images and issues drive commands to the drive system to maneuver the robot in the scene based on the object location.

49. The mobile robot of claim 48, wherein the imaging device determines a time-of-flight between emitting the light and receiving reflected light from the scene, the controller using the time-of-flight for determining a distance to the reflecting surfaces of the object.

50. The mobile robot of claim 48, wherein the imaging device comprises:

a light source for emitting light onto the scene; and

an imager for receiving reflections of the emitted light from the scene;

wherein the imager comprises an array of light detecting pixels.

51. The mobile robot of claim 41, wherein the imaging device comprises first and second portions,

the first portion arranged to emit light substantially onto the ground and receive reflections of the emitted light from the ground, and

the second portion arranged to emit light into a scene substantially above the ground and receive reflections of the emitted light from the scene about the robot.

52. The mobile robot of claim 41, wherein the imaging device comprises:

a speckle emitter emitting a speckle pattern of light onto a scene along a drive direction of the robot; and

an imager receiving reflections of the speckle pattern from an object in the scene;

wherein the controller;

stores reference images of the speckle pattern as reflected off a reference object in the scene, the reference images captured at different distances from the reference object; and

compares at least one target image of the speckle pattern as reflected off a target object in the scene with the reference images for determining a distance of the reflecting surfaces of the target object.

53. The mobile robot of claim 52, wherein the controller determines a primary speckle pattern on the target object and computes at least one of a respective cross-correlation and a decorrelation between the primary speckle pattern and the speckle patterns of the reference images.

54. The mobile robot of claim 41, wherein the imaging sensor scans side-to-side with respect to the forward drive direction to increase a lateral field of view and/or up-and-down to increase a vertical field of view of the imaging sensor.

55. The mobile robot of claim 41, wherein the controller ceases use of the received point cloud signals after a threshold period of time after receipt for issuing drive commands to the drive system.

56. The mobile robot of claim 55, wherein the controller suspends cessation of use of the received point cloud signals upon determining the presence of an object in the volume of space undetectable by the volumetric point cloud imaging device based on the received detection signals from the dead zone sensor.

57. The mobile robot of claim 56, wherein the controller continues ceasing use of the received point cloud signals after the threshold period of time after receipt upon determining that the volume of space undetectable by the volumetric point cloud imaging device is free of any objects, preferably based on the received detection signals from the dead zone sensor.

58. A mobile robot comprising:

a drive system configured to maneuver the robot over a floor surface, the drive system having a forward drive direction;

a controller in communication with the drive system;

a torso body defining a curved forward face supported above the drive system; and

an array of sensors disposed on the curved forward face of the torso body, the array of sensors comprising first, second, and third sensors in communication with the controller, the first sensor arranged to aim downward and away from the robot body, the second sensor arranged to aim away from the robot body substantially parallel with the floor surface, and the third sensor arranged to aim upward and away from the robot body.

59. The mobile robot of claim 58, wherein at least one sensor comprises a volumetric point cloud imaging device capable of obtaining a point cloud from a volume of space adjacent the robot.

60. The mobile robot of claim 58, wherein at least one sensor comprises a sonar proximity sensor or an infrared proximity sensor.

61. The mobile robot of claim 58, wherein the array of sensors comprises first and second imaging sensors disposed on the torso body and in communication with the controller, the first imaging sensor arranged to aim downward and away from the robot body, and the second imaging sensor arranged to aim away from the robot body substantially parallel with the floor surface.

62. The mobile robot of claim 61, wherein the array of sensors comprises a third imaging sensors disposed on the torso body and in communication with the controller, the third imaging sensor arranged to aim upward and away from the robot body.

63. The mobile robot of claim 58, wherein the array of sensors comprises first, second, and third proximity sensors disposed on the torso body, the first proximity sensor arranged to aim downward and away from the robot body, the second proximity sensor arranged to aim away from the robot substantially parallel to the floor surface, and the third proximity sensor arranged to aim upward and away from the robot.

64. The mobile robot of claim 58, wherein at least one sensor scans side-to-side to increase a field of view of the sensor.

65. A mobile robot comprising:

a robot body;

a drive system supporting the robot body and configured to maneuver the robot over a floor surface, the drive system having a forward drive direction;

a controller in communication with the drive system; and

first, second, and third imaging devices disposed on the robot body and in communication with the controller, the first imaging sensor arranged to aim downward and away from the robot body, the second imaging sensor arranged to aim away from the robot body substantially parallel with the floor surface, and the third imaging sensor arranged to aim upward and away from the robot body.

66. The mobile robot of claim 65, wherein the imaging sensors are disposed in a recess defined by the robot body while maintaining corresponding fields of view unobstructed by the robot body.

67. The mobile robot of claim 65, wherein at least one imaging sensor comprises a volumetric point cloud imaging device capable of obtaining a point cloud from a volume of space adjacent the robot.

68. The mobile robot of claim 65, wherein at least one imaging sensor scans side-to-side with respect to the forward drive direction to increase a lateral field of view of the imaging sensor.

69. The mobile robot of claim 65, further comprising first, second, and third proximity sensors disposed on the robot body, the first proximity sensor having a sensing axis arranged substantially parallel with an imaging axis of the first imaging sensor, the second proximity sensor having a sensing axis arranged substantially parallel with an imaging axis of the second imaging sensor, and the third proximity sensor having a sensing axis arranged substantially parallel with an imaging axis of the third imaging sensor.

70. The mobile robot of claim 69, wherein the first, second, and third proximity sensors comprise a sonar sensor or an infrared sensor and are each disposed adjacent the corresponding first, second, and third imaging sensors.

71. A method of operating a mobile robot, the method comprising:

maneuvering the robot across a floor surface in a forward drive direction;

receiving image data from first, second, and third imaging devices disposed on the robot and directed along the forward drive direction, the first imaging sensor arranged to aim downward and away from the robot, the second imaging sensor arranged to aim away from the robot body substantially parallel with the floor surface, and the third imaging sensor arranged to aim upward and away from the robot; and

maneuvering the robot across the floor surface based on the received image data.

72. The method of claim 71, further comprising:

receiving three-dimensional depth image data of a scene about the robot along a drive direction of the robot;

determining a local perceptual space corresponding to an environment around the robot based on the received three-dimensional depth image data;

determining a location of an object in the scene;

assigning a confidence level for the object location; and

maneuvering the robot in the scene based on the object location and corresponding confidence level.

73. The method of claim 72, further comprising constructing an object occupancy map of the scene.

74. The method of claim 72, further comprising degrading the confidence level of each object location over time unless persisted with updated three-dimensional depth image data.

75. The method of claim 71, further comprising scanning at least one imaging sensor side-to-side with respect to the forward drive direction to increase a lateral field of view of the imaging sensor.

76. The method of claim 71, further comprising:

receiving proximity data from first, second, and third proximity sensors disposed on the robot, the first proximity sensor having a sensing axis arranged substantially parallel with an imaging axis of the first imaging sensor, the second proximity sensor having a sensing axis arranged substantially parallel with an imaging axis of the second imaging sensor, and the third proximity sensor having a sensing axis arranged substantially parallel with an imaging axis of the third imaging sensor; and

maneuvering the robot across the floor surface based on the received proximity data.

77. The method of claim 76, wherein at least one proximity sensor comprises a sonar sensor or an infrared sensor.