Mobile robotic vehicle

• US 8,573,335 B2
• Filed: 12/20/2012
• Issued: 11/05/2013
• Est. Priority Date: 12/09/2008
• Status: Active Grant

• Current Assignee: Flir Detection, Inc. (Teledyne Technologies Incorporated)
• Original Assignee: iRobot Corporation
• Inventors: Rudakevych, Pavlo E.
• Primary Examiner(s): ADAMS, TASHIANA R
• Application Number:
  US13/721,918
• Publication Number:
  US 20130256042A1
• Time in Patent Office: 320 Days
• Field of Search: 180/9.32, 180/9.28, 180/9.1, 180/8.2, 180/8.7, 180/8.5, 180/907
• US Class Current: 180/9.32
• CPC Class Codes: B62D 55/06 with tracks without ground wheels
• CPC Class Codes: B62D 55/075 Tracked vehicles for ascending or descending stairs, steep slopes or vertical surfacesmagnetic or pneumatic ground-engaging parts B62D55/265; chairs or multi-track cycles specially adapted for invalids A61G5/00
• CPC Class Codes: Y10S 901/01 Mobile robot

Abstract

A mobile robot includes a robot chassis having a forward end, a rearward end and a center of gravity. The robot includes a driven support surface to propel the robot and first articulated arm rotatable about an axis located rearward of the center of gravity of the robot chassis. The arm is pivotable to trail the robot, rotate in a first direction to raise the rearward end of the robot chassis while the driven support surface propels the chassis forward in surmounting an obstacle, and to rotate in a second opposite direction to extend forward beyond the center of gravity of the robot chassis to raise the forward end of the robot chassis and invert the robot endwise.

Claims

1. A robot comprising:

a robot chassis having a forward end, a rearward end and a center of gravity;

a support surface moveably connected to the chassis and configured to propel the robot chassis;

a trailing arm rotatable about an axis located rearward of the center of gravity of the robot chassis; and

a controller configured to execute a stair climbing control routine stored on the mobile robot, including causing the robot to perform operations comprising;

driving the support surface over an underlying surface towards a stair;

pivoting the trailing arm downward against the underlying surface and causing the forward end of the robot chassis to raise up off the underlying surface, the trailing arm having a distal end that contacts the underlying surface forward of the center of gravity of the vehicle;

further driving the support surface to cause the forward end of the vehicle to ascend a riser of the stair, the support surface generating sufficient traction against the riser to climb the riser as the support surface is driven; and

pivoting the trailing arm so that the distal end contacts the underlying surface at a point behind the support surface while the robot ascends the stair.

2. The robot of claim 1, wherein pivoting the trailing arm so that the distal end contacts the underlying surface at a point behind the support surface comprises pivoting the trailing arm to raise a rearward end of the vehicle while the forward end of the support surface is supported by the first stair.

3. The robot of claim 1, wherein pivoting the trailing arm so that the distal end contacts the underlying surface at a point behind the support surface comprises:

pivoting the trailing arm to raise the rearward end while the forward end is supported by the first stair;

driving the support surface to advance the forward end over an uppermost edge of the first stair riser; and

pivoting the arm to further raise the rearward end such that the forward end tips downward beyond the uppermost edge of the riser of the first stair.

4. The robot of claim 3, wherein pivoting the trailing arm to raise the rearward end while the forward end is supported by the first stair comprises pivoting the trailing arm at a first rotational speed, and then pivoting the trailing arm at a second rotational speed greater than the first rotational speed.

5. The robot of claim 1, wherein the operations further comprise climbing another stair.

6. The robot of claim 1, wherein pivoting the trailing arm downward against the underlying surface and causing the forward end to raise up off the underlying surface comprises pivoting the trailing arm in a clockwise direction;

and pivoting the trailing arm so that the distal end contacts the underlying surface at a point behind the support surface comprises pivoting the trailing arm in a counter-clockwise direction.

7. The robot of claim 1, wherein the operations further comprise pivoting the trailing arm to an upwards position perpendicular to the support surface prior to pivoting the trailing arm so that the distal end contacts the underlying surface at the point behind the support surface.

8. The robot of claim 7, wherein pivoting the trailing arm to an upwards position perpendicular to the support surface does not substantially shift the center of gravity of the robot.

9. The robot of claim 1, wherein pivoting the trailing arm downward against the underlying surface raises the support surface to a predetermined angle of incline.

10. The robot of claim 9, wherein the predetermined angle of incline is an angle at which frictional forces between the support surface and the underlying surface and between the support surface and the stair are sufficiently balanced to prevent backsliding of the vehicle.

11. The robot of claim 1, wherein further driving the support surface to cause the forward end to contact and ascend a riser of the stair comprises lifting the trailing arm and using an accelerometer to detect backsliding.

12. The robot of claim 11, further comprising pivoting the trailing arm to adjust an angle of incline of the support surface in response to detecting backsliding.

13. The robot of claim 11, further comprising pivoting the trailing arm away from the underlying surface in response to detecting no backsliding.

14. The robot of claim 1, wherein the support surface includes a flexible track trained about a pair of wheels.

15. The robot of claim 14, wherein the axis of the trailing arm is coaxial with an axis of one of the wheels.

16. The robot of claim 1, further comprising a second arm rotatable about the axis with the trailing arm.

17. The robot of claim 16, wherein the trailing arm and the second arm are located outward of the driven support surface and are continuously rotatable in either direction.

18. The robot of claim 1, where in the trailing arm is located substantially along a central longitudinal axis of the robot chassis.

19. The robot of claim 1, further comprising a radio transceiver and wherein the controller is configured to rotate the trailing arm to raise the robot and elevate the transceiver.

20. The robot of claim 1, wherein the vehicle substantially fits within a bounding volume approximately 7 inches long, 5 inches wide and 2 inches tall.