Robotic Platform

• US 20080236907A1
• Filed: 06/13/2008
• Published: 10/02/2008
• Est. Priority Date: 03/27/1998
• Status: Active Grant

• Current Assignee: Flir Detection, Inc. (Teledyne Technologies Incorporated)
• Original Assignee: iRobot Corporation
• Inventors: Won, Chikyung
• Granted Patent: US 8,113,304 B2
• Time in Patent Office: Days
• US Class Current: 180/9.32
• CPC Class Codes: B25J 11/0025 handling explosives, bombs or hazardous objects
• CPC Class Codes: B25J 5/005 mounted on endless tracks or belts
• CPC Class Codes: B62D 55/065 Multi-track vehicles, i.e. more than two tracks soil-shifting machines E02F; mining machines E21C
• CPC Class Codes: B62D 55/0655 Articulated endless track vehicles steering specially adapted for trailers B62D13/00; articulated buses B62D47/025; tractor-trailer combinations or road trains comprising a uni-axle unit and a uni-axle trailer B62D53/02
• 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: B62D 55/12 Arrangement, location, or adaptation of driving sprockets
• CPC Class Codes: B62D 55/14 Arrangement, location, or adaptation of rollers
• CPC Class Codes: B62D 55/244 Moulded in one piece, with either smooth surfaces or surfaces having projections, e.g. incorporating reinforcing elements
• CPC Class Codes: Y10S 180/901 Devices for traversing vertical surfaces
• CPC Class Codes: Y10S 280/901 Adaptation of nonspecialized vehicles to semitrailer tractors

Abstract

An articulated tracked vehicle that has a main section, which includes a main frame, and a forward section. The main frame has two sides and a front end, and includes a pair of parallel main tracks. Each main track includes a flexible continuous belt coupled to a corresponding side of the main frame. The forward section includes an elongated arm. One end of the arm is pivotally coupled to the main frame near the forward end of the main frame about a transverse axis that is generally perpendicular to the sides of the main frame. The arm has a length sufficiently long to allow the forward section to extend below the main section in at least some degrees of rotation of the arm, and a length shorter than the length of the main section. The center of mass of the main section is located forward of the rearmost point reached by the end of the arm in its pivoting about the transverse axis. The main section is contained within the volume defined by the main tracks and is symmetrical about a horizontal plane, thereby allowing inverted operation of the robot.

Claims

1. A method for operating a robotic platform to climb a set of stairs, the method comprising:

pivoting right and left front arms to raise higher than the rise of the first, bottom-most stair of the set of stairs;

approaching the first stair of the set of stairs until the front arms contact the first stair;

driving the main tracks until the main tracks contact the first stair;

pivoting the front arms to extend a tracked base of the vehicle; and

driving the main tracks to ascend the set of stairs;

wherein each front arm is mounted on a corresponding side of right and left main tracks disposed on corresponding sides of a main body, each main track being trained about a corresponding main drive pulley and a corresponding rear idler pulley, each front arm pivoting about an articulation axis co-axially with the main drive pulleys to pivot with respect to the main body.

2. The method of claim 1, further comprising pivoting the right and left front arms in unison by an articulator drive motor coupled to right and left front arms.

3. The method of claim 2, further comprising pivoting the right and left front arms without rotation of the articulator drive motor when a torque between one of the front arms and the main body, caused by a force acting on the one front arm, exceeds a maximum torque that can be provided by the articulator drive motor.

4. The method of claim 3, wherein a slip clutch is coupled between the articulator drive motor and the front arms.

5. The method of claim 2, wherein each front arm comprises:

a front drive pulley concentric with and coupled to rotate in unison with the corresponding main drive pulley,

an arm side plate mounted to extend from the front drive pulley, beside the main body,

a front idler pulley rotatably mounted at a distal end of the side plate, and

a front arm track trained about the front drive pulley and front idler pulley;

wherein the articulator drive motor is coupled to the arm side plate of each front arm to pivot the coupled front arm about the articulation axis, the front arm being capable of pivoting a continuous 360 degrees about the articulation axis.

6. The method of claim 1, wherein pivoting the right and left front arms to raise higher than the rise of the first step comprises pivoting the front arms from a stowed position, in which the front arms are next to the corresponding side plates of the main body and the front arm tracks provide traction with the main tracks in a compact track configuration, and a deployed position, in which the front arm are pivoted at an angle with respect to the main tracks higher than the rise of the first step.

7. The method of claim 1, further comprising moving a payload from a neutral position to a forward position, the payload being disposed on top of the main body, wherein the payload is positioned substantially over a center of mass of the robotic platform in the neutral position and substantially forward of a center of mass of the robotic platform in the forward position.

8. A method for operating a robotic platform having first and second sets of right and left tracks disposed on corresponding sides of a main body to climb a set of stairs, the method comprising:

pivoting the first set of right and left tracks to raise higher than the rise of the first, bottom-most stair of the set of stairs;

approaching the first stair of the set of stairs until the first set of tracks contact the first stair;

driving at least the second set of tracks until the second set of tracks contacts the first stair;

pivoting the first set of tracks to extend a tracked base of the vehicle; and

driving the main tracks to ascend the set of stairs;

wherein each track is trained about a corresponding drive pulley and a corresponding idler pulley, wherein the right and left tracks of the first set each comprise an arm mounted on a side of the corresponding drive pulley opposite the main body, the arm being rigidly coupled to an articulator axle to pivot with respect to the main body, the corresponding idler pulley of each second set track being rotatably mounted at a distal end of an arm side plate mounted to extend from the corresponding drive pulley beside the main body.

9. The method of claim 8, further comprising differentially driving the right drive pulleys and left drive pulleys to provide skid steering.

10. The method of claim 8, wherein pivoting the first set of tracks to extend a tracked base of the vehicle comprises pivoting the first set of tracks forward of the main body, such that a center of gravity of the robotic platform is located at least 13 inches rearward of a distal end of each arm and at least 13 inches forward of the rear most point of the second set of right and left tracks.

11. The method of claim 8, further comprising pivoting the right and left arms of the first set of tracks with an articulator drive motor coupled to the articulator axle, the articulator drive motor being capable of pivoting the articulator axle and the arms of the first set of tracks in a continuous 360 degrees.

12. The method of claim 8, further comprising maintaining the center of mass of the robotic platform within an envelope of the 360 degree rotation of the arms.

13. The method of claim 8, further comprising moving a payload from a neutral position to a forward position, the payload being disposed on top of the main body, outside of the payload volume defined by the main tracks, wherein the payload is positioned substantially over a center of mass of the robotic platform in the neutral position and substantially forward of a center of mass of the robotic platform in the forward position.

14. The method of claim 13, further comprising moving a mast of the payload attached to the main body to extend away from the top of the robot.

15. The method of claim 8, further comprising independently driving the right and left arms for independent rotation about an articulation axis co-axial with the corresponding drive pulleys.

16. A method for operating a robotic platform to climb a set of stairs, the method comprising:

approaching the set of stairs with right and left front arms, mounted on a corresponding side of right and left main tracks disposed on corresponding sides of a main body, in a stowed position, in which the front arms are next to the right and left main tracks, each main track trained about a corresponding main drive pulley and a corresponding rear idler pulley;

rotating right and left front arms from the stowed position downward and away from the right and left main tracks, raising and supporting the main body on the front arms;

rotating the front arms to drive the upright main body past a vertical position, causing the robot to fall over and thereby invert the main body onto the set of stairs; and

driving the main tracks to ascend the set of stairs;

wherein a center of mass of the robotic platform is contained within an envelope of 360 degree rotation of the front arms.

17. The method of claim 16, further comprising:

driving the main tracks of the inverted robotic platform until the front arms contact the first stair; and

pivoting the front arms to extend a tracked base of the vehicle, before driving the main tracks to ascend the set of stairs.

18. The method of claim 16, further comprising pivoting each front arm about an articulation axis co-axially with the main drive pulleys to pivot with respect to the main body.

19. The method of claim 16, further comprising pivoting each front arm with an articulator drive motor coupled to the arm side plate of each front arm for rotation about the articulation axis.

20. The method of claim 19, further comprising pivoting the right and left front arms in unison by the corresponding coupled articulator drive motor.

21. The method of claim 20, further comprising pivoting the right and left front arms without rotation of the articulator drive motor when a torque between one of the front arms and the main body, caused by a force acting on the one front arm, exceeds a maximum torque that can be provided by the articulator drive motor.