Simplified and symmetrical five-bar linkage driver for manipulating a Six-Degree-of-Freedom Parallel "minimanipulator" with three inextensible limbs

• US 5,301,566 A
• Filed: 08/20/1993
• Issued: 04/12/1994
• Est. Priority Date: 07/20/1992
• Status: Expired due to Fees

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Tsai, Lung-Wen, Tahmasebi, Farhad
• Primary Examiner(s): Braun, Leslie A.
• Assistant Examiner(s): LAUB, DAVID
• Application Number:
  US08/110,181
• Time in Patent Office: 235 Days
• Field of Search: 74/469, 74/471 XY, 74/479 R, 74/479 B, 74/479 BP, 74/479 P, 74/479 PP, 74/519, 74/105, 74/106, 74/96, 901/14, 901/15, 901/16, 901/17, 901/18, 901/19, 901/27
• US Class Current: 74/490.01
• CPC Class Codes: B25J 17/0266 comprising more than two actuating or connecting rods
• CPC Class Codes: B25J 9/0036 with kinematics chains of the type prismatic-rotary-rotary
• CPC Class Codes: B25J 9/0048 with kinematics chains of the type rotary-rotary-rotary
• CPC Class Codes: B25J 9/106 with articulated links
• CPC Class Codes: G05G 9/04737 with six degrees of freedom
• CPC Class Codes: Y10T 74/20 Control lever and linkage systems
• CPC Class Codes: Y10T 74/20305 Robotic arm

Abstract

A Six-Degree-of-Freedom Parallel-Manipulator having three inextensible limbs for manipulating a platform is described in which the three inextensible limbs are attached via universal joints to the platform at non-collinear points. Each of the inextensible limbs is also attached via universal joints to a two-degree-of-freedom parallel driver such as a five-bar lineage, a pantograph, or a bidirectional linear stepper motor. The drivers move the lower ends of the limbs parallel to a fixed base and thereby provide manipulation of the platform. The actuators are mounted on the fixed base without using any power transmission devices such as gears or belts.

Claims

1. A six-degree-of-freedom parallel manipulator comprising:

three inextensible limbs each having a first end and a second end;

each of said inextensible limbs moveably attached at said first end to a platform at non-collinear points on said platform; and

three simplified five-bar linkage planar driver means affixed to a base member and moveably attached to each said second end of said inextensible limbs for providing planar movement to each said second end of each said inextensible limb thereby providing manipulation of said platform;

each said simplified five-bar linkage planar driver means having two coaxial rotary actuators as driving means for each said five-bar linkage planar driver means.

2. The device of claim 1 wherein each of said inextensible limbs are moveably attached at each end with joints such that each limb is provided with six degrees of freedom.

3. The device of claim 2 wherein each said limb has a three-degree-of-freedom spherical joint at said second end and a revolute joint at said first end.

4. The device of claim 2 wherein each said limb has a two-degree-of-freedom universal joint at each end.

5. The device of claim 4 wherein one of the axes of the universal joint at said first end is collinear with its limb, and the other axes of the universal joint at said first end as well as one axes of the universal joint at said second end are perpendicular to its limb.

6. The device of claim 1 wherein each said simplified five-bar linkage planar driver means is arranged as a speed reduction five bar linkage.

7. A simplified five-bar linkage for manipulating robotic limbs comprising:

a first rotary actuator having a first link connected thereto at one end of said first link;

a second rotary actuator having a second link connected thereto at one end of said second link;

a third link connected at one end to the other end of said first link;

a fourth link connected at one end to the other end of said second link;

said third and fourth links connected at their ends not connected to said first and second links thereby forming an output point;

said first and second rotary actuators being coaxial.

8. The simplified five-bar linkage of claim 7 wherein the length of said first link is equal to the length of said second link.

9. The simplified five-bar linkage of claim 8 wherein the length of said third link is equal to the length of said fourth link.

10. The simplified five-bar linkage of claim 7 wherein said four links are equal in length.