Mobile robot

• US 8,958,911 B2
• Filed: 07/23/2012
• Issued: 02/17/2015
• Est. Priority Date: 02/29/2012
• Status: Active Grant

• Current Assignee: Ava Robotics, Inc.
• Original Assignee: iRobot Corporation
• Inventors: Wong, Cheuk Wah, Rauhut, Eben, Benson, Brian C., Lydon, Peter J., Rosenstein, Michael T., Halloran, Michael, Shamlian, Steven V., Won, Chikyung, Chiappetta, Mark, Kearns, Justin H., Taka, Orjeta, Pack, Robert Todd, Farlow, Timothy S., Vicenti, Jasper Fourways
• Primary Examiner(s): HOLLOWAY, JASON R
• Application Number:
  US13/555,529
• Publication Number:
  US 20130226344A1
• Time in Patent Office: 939 Days
• Field of Search: 700/247, 700/250, 700/252, 700/253, 700/255, 700/258, 700/259, 901/1, 901/46
• 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; and

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

a first interface supported by the robot body;

a second interface spaced from the first interface and configured to receive a payload;

a collar rotatably supported between the first and second interfaces and having a curved wall formed at least partially as a surface of revolution about a vertical collar 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 vertical collar axis of rotation relative to the first and second interfaces and the robot body;

wherein all rotating portions of the volumetric point cloud sensor extend a lesser distance from the vertical 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 vertical 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 vertical 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 vertical collar axis to observe separate sub-volumes of the observed volume of space, the separate sub-volumes being displaced from one another along the vertical 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 vertical collar axis to observe the volume of space adjacent the robot at a height along the vertical 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 vertical 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 from the vertical 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 vertical 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 vertical 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 robot with 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 vertical collar axis by an angle of between about 45°

and about 65°

.

15. The mobile robot of claim 1, further comprising an actuator moving a portion of the robot body through a volume of space adjacent the mobile robot, 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 sensor pod of a mobile robot having a robot body, the sensor pod comprising:

a first interface supported by the robot body;

a second interface spaced from the first interface and configured to receive a payload;

a collar rotatably supported between the first and second interfaces and having a curved wall formed at least partially as a surface of revolution about a vertical collar axis of rotation with respect to a floor surface supporting the mobile robot;

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;

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; and

a collar actuator rotating the collar and the first and second volumetric point cloud sensors together about the vertical collar axis of rotation relative to the first and second interfaces and the robot body.

17. The sensor pod of claim 16, wherein the observation axis of the second volumetric point cloud sensor is angled with respect to a plane normal to the vertical collar axis and with respect to the first observation axis to observe a sub-volume of the observed volume of space displaced along the vertical collar axis by a distance greater than or equal to a diameter of the collar.

18. The sensor pod of claim 16, wherein the first observation axis is angled with respect to a plane normal to the vertical collar axis by between about 45°

and about 65°

.

19. The sensor pod of claim 16, wherein all rotating portions of the volumetric point cloud sensors extend a lesser distance from the vertical collar axis of rotation than an outermost point of the collar.

20. The sensor pod of claim 16, wherein the surface of revolution of the curved wall sweeps about 360 degrees about the vertical collar axis to form a substantially complete perimeter of the collar.

21. A sensor pod of a mobile robot having a robot body, the sensor pod comprising:

a first interface supported by the robot body;

a second interface spaced from the first interface and configured to receive a payload;

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 vertical collar axis of rotation with respect to a floor surface supporting the mobile robot;

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 vertical collar axis of rotation relative to the first and second interfaces and the robot body; and

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

22. The sensor pod of claim 21, wherein all rotating portions of the volumetric point cloud sensor extend a lesser distance from the vertical collar axis than an outermost point of the collar.

23. The sensor pod of claim 21, wherein the 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.

24. The sensor pod of claim 23, 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.

25. The sensor pod of claim 21, 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.