Bionic wrist joint based on asymmetric 3-RRR parallel mechanism

Patent metadata

Field	Value
Publication number	US-11786380-B2
Application number	US-202117488318-A
Country	US
Kind code	B2
Filing date	Sep 29, 2021
Priority date	May 17, 2021
Publication date	Oct 17, 2023
Grant date	Oct 17, 2023

Abstract

The invention discloses a bionic wrist joint based on an asymmetric 3-RRR parallel mechanism, including: an asymmetric 3-RRR parallel mechanism and a drive unit. The asymmetric 3-RRR parallel mechanism includes: a moving platform, a first static platform, and three asymmetrically distributed parallel branch chains, wherein each branch chain includes a passive rod and an active rod. An end of the active rod is connected to the first static platform via the revolute pair, and another end thereof is connected to the passive rod via the revolute pair. The axes of the revolute pairs at two ends of the active rod form an axis included angle. Three axis included angles are different, the passive rod and the moving platform are connected by the revolute pair, and three axis included angles corresponding to the passive rods are different. The drive unit is configured to drive the asymmetric 3-RRR parallel mechanism to move.

First claim

What is claimed is:

1. A bionic wrist joint based on an asymmetric 3-RRR parallel mechanism, comprising: an asymmetric 3-RRR parallel mechanism and a drive unit,
wherein the asymmetric 3-RRR parallel mechanism comprises: a moving platform, a first static platform, and three asymmetrically distributed parallel branch chains, wherein each of the branch chains comprises a passive rod and an active rod;
an end of the active rod is connected to the first static platform via a revolute pair, and another end thereof is connected to the passive rod via the revolute pair, the axes of the revolute pairs at two ends of the active rod form an axis included angle, three active rods form three different axis included angles, the passive rod and the moving platform are connected by the revolute pair, and three axis included angles corresponding to three passive rods are also different;
the drive unit is configured to drive the asymmetric 3-RRR parallel mechanism to move.

2. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 1 , wherein the three revolute pairs connected to the three active rods on the three branch chains and the first static platform are distributed on a same circle, every two revolute pairs are connected to a center of the circle to form an included angle, the three revolute pairs are combined in pairs to form three included angles, and the three included angles are different from one another.

3. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 2 , wherein the three revolute pairs connected to the three passive rods on the three branch chains and the moving platform are distributed on a same circle, and an included angle formed between pairs of revolute pairs of the passive rods connected to the moving platform and a center of the circle is the same as a corresponding included angle of the active rod on the same branch chain.

4. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 1 , wherein a range of the axis included angle of the active rod is 75° to 95°.

5. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 1 , wherein a range of the axis included angle of the passive rod is 70° to 100°.

6. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 2 , wherein a range of the included angle formed by the connection of the two revolute pairs and the center of the circle is 115° to 125°, and a sum of the three included angles is 360°.

7. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 1 , wherein a distribution of the three branch chains is:
taking a center of the asymmetric 3-RRR parallel mechanism as a center of a sphere, dividing a space into a plurality of continuous spherical surfaces with radii having equal difference at equal intervals, wherein adjacent spherical surfaces form one hollow sphere space, wherein in the three branch chains, all of the passive rods are distributed in one hollow sphere space, and all of the active rods are distributed in a plurality of adjacent hollow sphere spaces.

8. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 1 , wherein a distribution of the three branch chains is:
taking a center of the asymmetric 3-RRR parallel mechanism as a center of a sphere, dividing a space into a plurality of continuous spherical surfaces with radii having equal difference at equal intervals, wherein adjacent spherical surfaces form one hollow sphere space, wherein in the three branch chains, all of the passive rods are distributed in a plurality of adjacent hollow sphere spaces, and all of the active rods are distributed in a plurality of adjacent hollow sphere spaces.

9. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 7 , wherein the hollow sphere spaces in which the active rods are distributed and the hollow sphere spaces in which the passive rods are distributed are not overlapped.

10. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 1 , wherein the drive unit comprises three motors and three reducers arranged in parallel, each of the active rods is connected to one motor and one reducer, the motor is configured to drive the active rod to move, and the reducer is configured to increase an output torque of the motor.

11. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 2 , wherein a range of the axis included angle of the active rod is 75° to 95°.

12. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 3 , wherein a range of the axis included angle of the active rod is 75° to 95°.

13. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 2 , wherein a range of the axis included angle of the passive rod is 70° to 100°.

14. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 3 , wherein a range of the axis included angle of the passive rod is 70° to 100°.

15. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 3 , wherein a range of the included angle formed by the connection of the two revolute pairs and the center of the circle is 115° to 125°, and a sum of the three included angles is 360°.

16. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 8 , wherein the hollow sphere spaces in which the active rods are distributed and the hollow sphere spaces in which the passive rods are distributed are not overlapped.

17. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 2 , wherein the drive unit comprises three motors and three reducers arranged in parallel, each of the active rods is connected to one motor and one reducer, the motor is configured to drive the active rod to move, and the reducer is configured to increase an output torque of the motor.

18. The bionic wrist joint based on the asymmetric 3-RRR parallel mechanism of claim 3 , wherein the drive unit comprises three motors and three reducers arranged in parallel, each of the active rods is connected to one motor and one reducer, the motor is configured to drive the active rod to move, and the reducer is configured to increase an output torque of the motor.

Assignees

• Univ Huazhong Science Tech

Inventors

• Chen Wen-Bin
• Fu Hao
• Zhang yu-lin
• Fan Xiang
• Zhou zhi-jie
• Xiong cai-hua

Classifications

• A61F2/585 Primary

  Wrist joints · CPC title

• A61F2/68 Primary

  Operating or control means · CPC title

• B25J17/0283

  Three-dimensional joints · CPC title

• B25J17/0291

  having axes crossing at an oblique angle, i.e. other than 90 degrees · CPC title

• A61F2002/5038

  Hinged joint, e.g. with transverse axle restricting the movement · CPC title