Variable stiffness robotic joint system

Patent metadata

Field	Value
Publication number	US-10040206-B2
Application number	US-201515539516-A
Country	US
Kind code	B2
Filing date	Aug 28, 2015
Priority date	Jan 5, 2015
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

The present invention relates to a variable rigidity robot joint system including a first driving module and a second driving module generating torque which is rotated on a first direction, a first rotating module changing rotations of the first driving module and the second driving module into rotations on a second direction intersecting the first direction when the first and second driving modules rotate in directions in which a joint is rotated in a same direction, thereby rotating the joint, a rigidity-providing member providing rigidity by elastically supporting a rotational movement of the first rotating module on the second direction, and a second rotating module changing rotations of the first driving module and the second driving module into a linear motion in the first direction when the first and second driving modules rotate in directions in which the joint is rotated in different directions.

First claim

The invention claimed is:

1. A variable stiffness robotic joint system comprising:
a first driving module and a second driving module configured to respectively generate torque which is rotated on a first direction;
a first rotating module configured to change rotations of the first driving module and the second driving module into rotations on a second direction intersecting the first direction when the first driving module and the second driving module rotate in directions in which a joint is rotated in a same direction, thereby rotating the joint;
a stiffness-providing member configured to provide stiffness by elastically supporting a rotational movement of the first rotating module on the second direction; and
a second rotating module configured to change rotations of the first driving module and the second driving module into a linear motion in the first direction when the first driving module and the second driving module rotate in directions in which the joint is rotated in different directions, thereby adjusting an elastic force of the stiffness-providing member.

2. The variable stiffness robotic joint system of claim 1 further comprising:
a first rotation shaft configured to rotate on the first direction according to the rotation of the first driving module, thereby transmitting the torque of the first driving module to the first rotating module and the second rotating module; and
a second rotation shaft configured to rotate on the first direction according to the rotation of the second driving module, thereby transmitting the torque of the second driving module to the first rotating module and the second rotating module.

3. The variable stiffness robotic joint system of claim 2 , wherein
the first rotating module includes:
a first joint shaft rotation gear configured to rotate on the second direction to rotate the joint; and
a pair of first cross shaft rotation gears respectively axis-connected the first rotation shaft and the second rotation shaft and configured to rotate in engagement with the first joint shaft rotation gear so as to rotate the first joint shaft rotation gear when the first driving module and the second driving module rotate in directions in which the joint is rotated in the same direction, and
the second rotating module includes:
a sliding frame configured to vary the elastic force of the stiffness-providing member according to sliding movement in the first direction of the sliding frame;
a second joint shaft rotation gear configured to rotate on the second direction; and
a pair of second cross shaft rotation gears respectively axis-connected to the first rotation shaft and the second rotation shaft and configured to rotate in engagement with the second joint shaft rotation gear so as to move the sliding frame in the first direction when the first driving module and the second driving module rotate in directions in which the joint is rotated in different directions.

4. The variable stiffness robotic joint system of claim 3 , wherein the stiffness-providing member includes a pair of elastic members configured to respectively elastically press the pair of first cross shaft rotation gears in the first direction.

5. The variable stiffness robotic joint system of claim 4 , wherein the sliding frame includes a pair of first gear plates configured to support opposite sides of each of the second cross shaft rotation gears in the first direction, and to move with the pair of the second cross shaft rotation gears when the second cross shaft rotation gears linearly move in the first direction in engagement with the second joint shaft rotation gear according to rotations of the first rotation shaft and the second rotation shaft, thereby linearly moving the sliding frame in the first direction.

6. The variable stiffness robotic joint system of claim 5 , wherein
the sliding frame further includes:
a second gear plate disposed between the first gear plates and the pair of first cross shaft rotation gears, and formed with a pair of through holes through which the first rotation shaft and the second rotation shaft pass, respectively,
the first rotating module further includes:
a pair of stoppers, each of the stoppers disposed at opposite sides of the pair of first cross shaft rotation gears, respectively with the second gear plate disposed between the pair of stoppers and the pair of first cross shaft rotation gears, and connected to the first cross shaft rotation gears through the through holes, respectively thereby being stopped by the through holes at the opposite sides of the first cross shaft rotation gears, respectively and
each of the elastic members elastically presses each of the stoppers in the first direction, respectively, to provide the elastic force to each of the pair of first cross shaft rotation gears, respectively.

7. The variable stiffness robotic joint system of claim 6 , wherein the elastic members provide the elastic force respectively to the first cross shaft rotation gears in the first direction, so as to elastically support forward torque and reverse torque transmitted from an outside through the joint and the first cross shaft rotation gears.

8. The variable stiffness robotic joint system of claim 6 , wherein the first cross shaft rotation gears are provided on the first rotation shaft and the second rotation shaft, respectively, so as to be freely movable in the first direction, thereby compressing or releasing the elastic members, respectively.

9. The variable stiffness robotic joint system of claim 5 further comprising:
a shaft supporting part configured to support each of the first rotation shaft and the second rotation shaft to be rotatable in the first direction; and
a main frame including a plate guide supporting the sliding frame to be linearly movable in the first direction.

10. The variable stiffness robotic joint system of claim 9 , wherein
the main frame further includes a pair of support plates spaced apart from each other in the first direction, and
the plate guide includes:
a plurality of fixed shafts provided between the support plates along the first direction; and
a sliding bearing module provided on the sliding frame to move linearly along each of fixed shafts.

11. The variable stiffness robotic joint system of claim 10 , wherein
the sliding frame further includes a connecting plate connecting the pair of first gear plates and the second gear plate,
the pair of first gear plates are disposed between the pair of support plates, and the second gear plate is disposed on a periphery of the pair of support plates, and
one of the pair of support plates, which is disposed between the first gear plates and the second gear plate, is formed with a plate through hole through which the connecting plate passes.

12. The variable stiffness robotic joint system of claim 10 , wherein
the main frame further includes a main plate extending in the first direction to connect the pair of support plates to each other, and
the first joint shaft rotation gear and the second joint shaft rotation gear are rotatably provided on the main plate.

13. The variable stiffness robotic joint system of claim 3 , wherein each of the first driving module and the second driving module includes:
a driving motor configured to generate torque; and
at least one torque-transmitting member configured to transmit the torque of the driving motor to the first and the second rotation shafts.

14. The variable stiffness robotic joint system of claim 13 , wherein
the driving motor is mounted to the sliding frame such that a rotation axis of the driving motor is formed in the first directio

Assignees

• Univ Korea Res & Bus Found

Inventors

• Jeong Hyun-Hwan
• Cheong Joo-No
• Kang Bong-Ki

Classifications

• B25J19/068

  Actuating means with variable stiffness · CPC title

• B25J18/04 Primary

  rotatable · CPC title

• B25J17/0208

  Compliance devices · CPC title

• B25J9/106

  with articulated links · CPC title

• B25J17/00 Primary

  Joints · CPC title