Three-dimensional passive walking robot

Patent metadata

Field	Value
Publication number	US-12496715-B2
Application number	US-202318379614-A
Country	US
Kind code	B2
Filing date	Oct 12, 2023
Priority date	Oct 12, 2022
Publication date	Dec 16, 2025
Grant date	Dec 16, 2025

Abstract

A bipedal walking robot uses a quasi-passive control scheme and a simplified mechanical design. The walking robot has a pair of legs connected to a body through a passive hip joint, which is offset from a center of gravity of the walking robot. A nonconcentric, curved foot is attached at to each leg by a prismatic joint. Extension and retraction of the prismatic joint initiates the walking sequence of the robot, with each foot retracted during the swing phase and extended during the stance phase. Directional changes are controlled by changing a phase offset in the actuation of each foot.

First claim

What is claimed is:

1 . A walking robot comprising:
a torso comprising a hip joint; a first leg and a second leg pivotally connected to the torso via the hip joint; a first foot connected to the first leg and a second foot connected to the second leg,
wherein each of the first foot and the second foot have rounded bottom surfaces, wherein the rounded bottom surfaces form a radius of curvature,
wherein the first foot and the second foot are tangent to a surface when at rest; and
a controller actuating an extension of the first foot and the second foot, wherein a center of gravity of the walking robot is below a center of the radius of curvature for the first foot and the second foot.

2 . The walking robot of claim 1 , wherein the first foot is connected to the first leg via a first prismatic joint and the second foot is connected to the second leg via a second prismatic joint.

3 . The walking robot of claim 1 , wherein the first prismatic joint and the second prismatic joint do not permit flexion.

4 . The walking robot of claim 1 , wherein the hip joint is offset from a center of gravity of the walking robot.

5 . The walking robot of claim 4 , wherein the hip joint is positioned forward of the center of gravity of the walking robot.

6 . The walking robot of claim 1 , wherein a center of gravity of the walking robot is below the hip joint.

7 . The walking robot of claim 1 , wherein the controller creates a sinusoidal trajectory for the first foot and the second foot.

8 . The walking robot of claim 1 , wherein the controller creates a periodic waveform trajectory for the first foot and the second foot.

9 . A method of controlling a bipedal walking robot having a pair of feet with rounded bottom surface, each foot connected to a leg through a prismatic joint, the method comprising:
extending the feet in a periodic trajectory having an amplitude, wherein a first foot of the pair of feet is offset by 180 degrees from the periodic trajectory of a second foot of the pair of feet, wherein extending the feet is accomplished using a single actuator in each of the first foot and the second foot without additional actuators.

10 . The method of claim 9 , wherein the offset is changed from 180 degrees.

11 . A walking robot comprising:
a first rigid body comprising a first leg and a first foot and a second rigid body comprising a second leg and a second foot,
wherein each of the first foot and the second foot has a rounded bottom surface,
wherein the first foot and the second foot are tangent to a surface when at rest;
a hip joint connecting the first rigid body to the second rigid body along an axis; an actuator operable connected to the first rigid body and the second rigid body,
wherein the actuator rotates the first rigid body and the second rigid body around the axis;
wherein a center of gravity of the walking robot is below a center of curvature for the first foot and a center of curvature for the second foot.

12 . The walking robot of claim 11 , wherein the axis is above a center of curvature for the first foot and a center of curvature for the second foot.

13 . The walking robot of claim 11 , wherein the axis is behind a center of gravity of the walking robot.

14 . The walking robot of claim 11 , wherein a center of curvature for each of the first foot and the second foot are displaced laterally from a center of gravity of the walking robot.

15 . A method of controlling a bipedal walking robot having a pair of feet with rounded bottom surface, each foot in the pair of feet rigidly connected to a leg and each leg connected to an actuator through a hip joint, the method comprising:
using a single actuator, lifting the feet in a periodic trajectory having an amplitude, wherein a first foot of the pair of feet is offset by 180 degrees from the periodic trajectory of a second foot of the pair of feet.

16 . The method of claim 15 , further comprising:
controlling forward walking and rotational movement using the single actuator.

17 . The walking robot of claim 1 , further comprising a single actuator connected to the hip joint for actuating the extension of the first foot and the second foot.

18 . The walking robot of claim 17 , excluding an additional actuator for active balancing.

Assignees

• Univ Carnegie Mellon

Inventors

• Johnson Aaron
• Bergbreiter Sarah
• Carter Kamal
• Islam Sharfin
• Yim Justin
• Kyle James

Classifications

• B62D57/032 Primary

  with alternately or sequentially lifted supporting base and legs; with alternately or sequentially lifted feet or skid (B62D57/024 takes precedence) · CPC title

• B25J9/1664 Primary

  characterised by motion, path, trajectory planning · CPC title