Obstacle traversing mobile robot

Patent metadata

Field	Value
Publication number	US-10967926-B2
Application number	US-201815953416-A
Country	US
Kind code	B2
Filing date	Apr 14, 2018
Priority date	Nov 2, 2015
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

Disclosed is a mobile robot adapted to traverse vertical obstacles. The robot comprises a frame and at least one wheel positioned in a front section of the robot, at least two middle wheels and at least two rear wheels. The at least one middle wheel and at least one rear wheel are connected by a tilting lever that is arranged on each of the opposing sides of or to the frame, forming a pair of wheels. Each tilting lever can be turned around a lever bearing located between the respective axial centers of rotation of each pair of wheels.

First claim

We claim:

1. A mobile robot comprising:
(a) a frame and at least one front wheel, at least two middle wheels and at least two rear wheels,
(b) wherein at least one middle wheel and at least one rear wheel are connected by a tilting lever arranged on each of opposing sides of or to the frame, forming a pair of wheels; and
(c) wherein each tilting lever can be turned around a lever bearing located between respective axial centers of rotation of each pair of wheels, and
further comprising at least one sensor constructed and adapted to sense at least one of: (i) an absolute angular position of the tilting lever, and/or (ii) a relative angular position of the tilting lever,
wherein the at least one sensor adapted to sense the relative angular position of the tilting lever is calibrated at a beginning of operation, by calibrating the at least one sensor at an extreme position of the lever.

2. The robot of claim 1 , wherein the tilting lever is adapted to rotate freely until a certain angle is reached, when the robot encounters uneven ground along its direction of movement, allowing the robot to traverse such uneven ground smoothly.

3. The robot of claim 1 , wherein the tilting lever can be turned around the lever bearing by at most 60° on either side.

4. The robot of claim 3 , wherein the tilting lever can be turned around the lever bearing by at least 55° on either side.

5. The robot of claim 3 , wherein the tilting lever can be turned around the lever bearing by at least 50° on either side.

6. The robot of claim 3 , wherein the tilting lever can be turned around the lever bearing by at between 45° and 20° on either side.

7. The robot of claim 1 , wherein said at least one sensor comprises one or more of: a Hall effect non-contact rotary position sensor, a potentiometer, an optical encoder, a magnetic encoder, and/or at least one visual camera-like system.

8. The robot of claim 1 , further comprising a lever turn motor adapted to start actuating the tilting lever upon receiving sensor data, said sensor data comprising data relating to one or more of: tilting angle, force applied to any of the wheels, visual data, Lidar data, and Hall effect non-contact rotation sensor data.

9. The robot of claim 1 , wherein the robot is adapted to climb obstacles of up to 18 cm by rotating the tilting lever.

10. The robot of claim 1 , wherein the tilting lever is adapted to rotate freely until a particular inclination angle is reached, at which point the lever turn motor is adapted to engage, such point being an engagement point.

11. The robot of claim 10 , wherein the tilting lever is adapted to rotate freely over a range of 25°-45° from one engagement point to a next engagement point.

12. The robot of claim 1 , further comprising at least one motor adapted to drive the wheels.

13. The robot of claim 12 , comprising at least two motors adapted to drive the wheels.

14. The robot of claim 1 , wherein the wheels are arranged on the frame such that the robot is supported by at least two wheels during normal travel along a surface.

15. The robot of claim 1 , wherein the robot's center of mass is located between a middle and a front end of the robot.

16. The robot of claim 15 , wherein the robot's center of mass is located between the middle and half of the distance from the middle to the front end of the robot.

17. A mobile robot comprising:
(a) a frame and at least one front wheel, at least two middle wheels and at least two rear wheels,
(b) wherein at least one middle wheel and at least one rear wheel are connected by a tilting lever arranged on each of opposing sides of or to the frame, forming a pair of wheels; and
(c) wherein each tilting lever can be turned around a lever bearing located between respective axial centers of rotation of each pair of wheels,
wherein the wheels have the same radius and wherein a maximum distance d between the at least one front wheel and the at least one middle wheel or between the at least one middle wheel and the at least one rear wheel measured from a rear-most facing point of the at least one middle wheel is defined by:

d
=

6
⁢

⁢

r
2

-

3
⁢

⁢

h
·
r

2
⁢

(

h
-
r

)

,

where d is the said maximum distance, r is the radius of the wheels and h is the maximum traversable height of an obstacle.

18. A climbing method of a mobile robot, said robot comprising a frame with at least one front wheel, at least two middle wheels and at least two rear wheels, wherein at least one middle wheel and at least one rear wheel are connected by a tilting lever that is arranged on each of opposing sides of or to the frame, forming a pair of wheels,
said method comprising:
(a) turning the tilting lever around a lever bearing located between respective axial centers of rotation of each pair of wheels when traversing an obstacle;
(b) engaging at least one lever turn motor once the tilting lever reaches a certain tilting angle;
(c) exerting a downward force on the middle wheels with a mechanism driven by the at least one lever turn motor so as to provide a counteracting vertical force on one or more front wheels and increase traction of the middle wheels, and to facilitate climbing of the front wheels;
(d) ceasing exerting the downward force on the one or more middle wheels after the front wheels have reached a top of the obstacle; and
(e) completing climbing of the obstacle through forward momentum of the robot generated by actuating the middle and/or back wheels.

19. The method of claim 18 , wherein the front, middle and back wheels are all actuated as the robot approaches the obstacle.

20. The method of claim 18 , wherein the method further includes sensing a position of the front wheels on the obstacle before ceasing applying the downward force on the one or more middle wheels.

Assignees

• Starship Tech Oue

Inventors

• Liivik Ivo
• Liivik Märt
• Liivik Tiit

Classifications

• B60G5/00 Primary

  Resilient suspensions for a set of tandem wheels or axles having interrelated movements · CPC title

• B60G2300/20

  Toys · CPC title

• B60B19/00

  Wheels not otherwise provided for or having characteristics specified in one of the subgroups of this group · CPC title

• B60G2300/07

  Off-road vehicles · CPC title

• B60B2900/911

  Eccentricity · CPC title