Methods for compact counter balance arms

• US 8,500,722 B2
• Filed: 10/14/2010
• Issued: 08/06/2013
• Est. Priority Date: 01/24/2005
• Status: Active Grant

• Current Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Original Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Inventors: Cooper, Thomas G.
• Primary Examiner(s): Thomson, Bill
• Assistant Examiner(s): LIPITZ, JEFFREY BRIAN
• Application Number:
  US12/905,030
• Publication Number:
  US 20110023285A1
• Time in Patent Office: 1,027 Days
• Field of Search: 248/280.11, 248/586, 606/1
• US Class Current: 606/1
• CPC Class Codes: A61B 2090/5025 with a counter-balancing mechanism
• CPC Class Codes: A61B 2090/506 using a parallelogram linkage, e.g. panthograph
• CPC Class Codes: A61B 2090/508 with releasable brake mechanisms
• CPC Class Codes: A61B 34/30 Surgical robots
• CPC Class Codes: A61B 34/37 Master-slave robots A61B34/35 takes precedence
• CPC Class Codes: A61B 34/71 Manipulators operated by drive cable mechanisms
• CPC Class Codes: A61B 90/50 Supports for surgical instruments, e.g. articulated arms
• CPC Class Codes: B25J 19/0016 using springs
• CPC Class Codes: G02B 7/001 Counterbalanced structures, e.g. surgical microscopes
• CPC Class Codes: Y10T 29/49826 Assembling or joining
• CPC Class Codes: Y10T 74/20311 including power cable or connector
• CPC Class Codes: Y10T 74/2154 Counterbalanced

Abstract

In one embodiment of the invention, a method for a set-up arm of a robotic surgical system is disclosed. The method includes balancing a linkage structure with a balancing mechanism to support a load; moving the linkage structure varying a moment at a pivot point due to the load at the end of a link of the linkage structure; and changing a path length of one or more cables over a plurality of pulleys in the balancing mechanism to compress or decompress a spring to respectively increase or decrease tension in the one or more cables to balance the variance in the moment.

Claims

1. A method for a set-up arm of a robotic surgical system, the method comprising:

balancing a linkage structure with a balancing mechanism to support a load, wherein the linkage structure includes a first set-up joint coupled to a supporting structure, a second set up joint adapted to couple to a robotic arm, and a counter balancing link pivotally coupled to the first set-up joint at a first pivot point and to the second set-up joint at a second pivot point, wherein the balancing mechanism has a plurality of pulleys including a first pulley rotatably coupled to the linkage structure at the first pivot point, a second pulley rotatably coupled to the first setup joint, and a third pulley rotatably coupled to the counter balancing link such that a distance from the second pulley varies as the counter balancing link pivots around the first pivot point;

moving the linkage structure in a first direction thereby varying a moment at the first pivot point due to the load being near an end of the second set-up joint of the linkage structure;

changing a path length of one or more cables over the plurality of pulleys in the balancing mechanism in response to the movement of the linkage structure in the first direction; and

compressing a spring in response to the change in the path length to increase tension in the one or more cables to balance the variance in the moment.

2. The method of claim 1, wherein

the balancing includes

tensioning the one or more cables in the balancing mechanism of the linkage structure to support the load.

3. The method of claim 1, wherein

the one or more cables is a plurality of cables, and

the balancing includes

tensioning the plurality of cables together in the balancing mechanism of the linkage structure to support the load.

4. The method of claim 3, wherein

the balancing further includes

prior to tensioning, independently pre-tensioning each cable of a plurality of cables in the balancing mechanism of the linkage structure to substantially equalize an initial tension in each.

5. The method of claim 1, further comprising:

moving the linkage structure in a second direction opposite the first direction to vary the moment at the first pivot point;

secondly changing the path length of the one or more cables over the plurality of pulleys in the balancing mechanism in response to the movement of the linkage structure in the second direction; and

decompressing the spring in response to the second change in the path length to decrease tension in the one or more cables to balance the variance in the moment.

6. The method of claim 5, wherein

the path length is increased to compress the spring and increase the tension in the one or more cables;

and

the path length is decreased to decompress the spring and decrease the tension in the one or more cables.

7. The method of claim 1, wherein

the path length is increased to compress the spring and increase the tension in the one or more cables.

8. The method of claim 3, wherein

each of the plurality of cables equally share the load.

9. The method of claim 1, wherein

the movement of the linkage structure varies a mechanical advantage of the balancing mechanism, and

the changing of the path length of one or more cables to compress or decompress the spring to respectively increase or decrease tension in the one or more cables in response to the variance in the mechanical advantage.

10. The method of claim 1, wherein

the linkage structure is a parallelogram linkage structure;

and

the balancing mechanism is a spring-cable-pulley balancing mechanism.

11. The method of claim 1, wherein

the supporting structure is a ceiling and the method further comprises coupling the linkage structure to the ceiling.

12. The method of claim 1, wherein

the supporting structure is an overhead support structure and the method further comprises coupling the linkage structure to the overhead support structure.

13. A method for a set-up arm of a robotic surgical system, the method comprising:

balancing a parallelogram linkage structure with a balancing mechanism to support a load of a surgical arm, wherein the parallelogram linkage structure includes a first set-up joint coupled to a supporting structure, a second set up joint adapted to couple to the surgical arm, and a counter balancing link pivotally coupled to the first set-up joint at a first pivot point and to the second set-up joint at a second pivot point, wherein the balancing mechanism has a plurality of pulleys including a first pulley rotatably coupled to the parallelogram linkage structure at the first pivot point, a second pulley rotatably coupled to the first setup joint, and a third pulley rotatably coupled to the counter balancing link such that a distance from the second pulley varies as the counter balancing link pivots around the first pivot point;

moving the parallelogram linkage structure thereby varying a moment at the first pivot point due to the load being near an end of the second set-up joint of the parallelogram linkage structure;

changing a path length of one or more cables over the plurality of pulleys in the balancing mechanism in response to the movement of the parallelogram linkage structure;

compressing a spring in response to the change in the path length of the one or more cables to increase tension in the one or more cables to balance the variance in the moment and decompressing the spring in response to the change in the path length of the one or more cables to decrease tension in the one or more cables to balance the variance in the moment; and

applying joint brakes to deter further movement in the parallelogram linkage structure.

14. The method of claim 13, wherein

the path length is increased to compress the spring and increase the tension in the one or more cables;

and

the path length is decreased to decompress the spring and decrease the tension in the one or more cables.

15. The method of claim 13, wherein

the supporting structure is a ceiling and the method further comprises coupling the linkage structure to the ceiling.

16. The method of claim 13, wherein

the supporting structure is an overhead support structure and the method further comprises coupling the linkage structure to the overhead support structure.

17. The method of claim 13, wherein

the balancing mechanism is a spring-cable-pulley balancing mechanism.

18. The method of claim 13, wherein

the one or more cables is a plurality of cables, and

the balancing includes

tensioning the plurality of cables together in the balancing mechanism of the parallelogram linkage structure to support the load.

19. The method of claim 18, wherein

the balancing further includes

prior to tensioning, independently pre-tensioning each cable of a plurality of cables in the balancing mechanism of the parallelogram linkage structure to substantially equalize an initial tension in each.