Devices, systems and methods for controlling cable drive mechanisms

Patent metadata

Field	Value
Publication number	US-12208520-B2
Application number	US-202218280874-A
Country	US
Kind code	B2
Filing date	Mar 7, 2022
Priority date	Mar 8, 2021
Publication date	Jan 28, 2025
Grant date	Jan 28, 2025

Abstract

A cable-driven device, such as a joint or instrument of a computer-assisted manipulator system, may comprise a capstan mechanism to wind/unwind cables. The capstan mechanism comprises a capstan that has a groove in an outer surface of the capstan to guide the cables, which are routed from a take-up pulley, to spool onto the capstan as the capstan rotates. A guide element is engaged with the groove. The guide element is held translationally stationary relative to the take-up pulley, while there is relative translation between the capstan and both the guide element and the take-up pulley. Thus, as the capstan rotates, the guide element engages with the groove and forces the capstan and the take-up pulley to translate relative to one another. This relative translation of the capstan and the take-up pulley may prevent deviation of a take-up angle of the cable as the cable spools onto the capstan.

First claim

What is claimed is:

1. A capstan mechanism, comprising:
a capstan comprising an outer surface;
a groove in the outer surface of the capstan, the groove configured to receive and guide a cable to spool onto the capstan as the capstan rotates;
a take-up pulley to route the cable onto and off from the capstan; and
a guide element engaged with the groove, the guide element causing relative translation between the capstan and the take-up pulley in response to rotation of the capstan.

2. The capstan mechanism of claim 1 , wherein:
the relative translation between the capstan and the take-up pulley comprises the capstan translating relative to a drive shaft that drives rotation of the capstan while the take-up pulley is translationally stationary relative to the drive shaft.

3. The capstan mechanism of claim 2 , further comprising:
a support structure that is translationally stationary relative to the drive shaft, wherein the guide element and the take-up pulley are coupled to and translationally stationary relative to the support structure and the capstan is translationally movable relative to the support structure.

4. The capstan mechanism of claim 3 , wherein:
the guide element is a guide roller that is rotatably coupled to the support structure and configured to roll along the groove.

5. The capstan mechanism of claim 4 , wherein:
the capstan has a capstan axis of rotation,
the guide roller has a guide roller axis of rotation, and
the guide roller axis of rotation is nonparallel to the capstan axis of rotation.

6. The capstan mechanism of claim 4 , wherein:
the groove spirals helically around the capstan at a helix angle relative to a normal plane of the capstan, the normal plane of the capstan being perpendicular to the capstan axis of rotation, and
an angle between a normal plane of the guide roller and the normal plane of the capstan is equal to the helix angle of the groove, the normal plane of the guide roller being perpendicular to a guide roller axis of rotation.

7. The capstan mechanism of claim 2 , further comprising:
a ball spline mechanism comprising the drive shaft and ball bearings positioned between the drive shaft and the capstan,
wherein the drive shaft is a spline drive shaft and rotation of the spline drive shaft causes rotation of the capstan and the capstan is translationally movable relative to the spline drive shaft.

8. The capstan mechanism of claim 7 , wherein:
the ball spline mechanism comprises a first groove in the spline drive shaft, a second groove in a radially-inward facing surface of a bore of the capstan, and a tube between the spline drive shaft and the capstan configured to hold the ball bearings, the ball bearings being engaged with the first and second grooves.

9. The capstan mechanism of claim 7 , wherein:
the ball spline mechanism comprises a recirculating ball spline unit coupled to the capstan and slidably coupled to the spline drive shaft.

10. The capstan mechanism of claim 1 , wherein:
the groove is a first groove spiraling helically around the outer surface of the capstan and the capstan mechanism further comprises a second groove spiraling helically around the outer surface of the capstan.

11. The capstan mechanism of claim 10 , further comprising:
one or more first cables, each wound onto the capstan in at least a portion of the first groove; and
one or more second cables each wound onto the capstan in at least a portion of the second groove.

12. The capstan mechanism of claim 11 , wherein:
the one or more second cables are configured to experience less stress than the one or more first cables.

13. The capstan mechanism of claim 12 , wherein:
the one or more second cables have a lower elastic modulus than the one or more first cables.

14. The capstan mechanism of claim 1 , wherein:
the relative translation between the capstan and the take-up pulley comprises the take-up pulley translating relative to a drive shaft that drives rotation of the capstan while the capstan is translationally stationary relative to the drive shaft.

15. The capstan mechanism of claim 14 , further comprising:
a support structure, wherein the guide element and the take-up pulley are coupled to and translationally stationary relative to the support structure and the support structure is translationally movable relative to the capstan.

16. The capstan mechanism of claim 1 , wherein:
the groove spirals helically around the outer surface of the capstan.

17. A manipulator system for supporting and remotely actuating instruments, comprising:
a manipulator comprising a first link, an instrument carriage, and a joint coupling the instrument carriage relative to the first link, wherein:
the instrument carriage is configured to support an instrument;
the joint comprises:
a capstan mechanism;
one or more cables coupled to the instrument carriage; and
one or more pulleys routing the cables between the instrument carriage and the capstan mechanism, wherein the capstan mechanism comprises:
a capstan comprising an outer surface;
a groove in the outer surface of the capstan, the groove configured to receive and guide a cable to spool onto the capstan as the capstan rotates;
one or more take-up pulleys to route the one or more cable onto and off from the capstan; and
a guide element engaged with the groove, the guide element causing relative translation between the capstan and the one or more take-up pulleys in response to rotation of the capstan.

18. The manipulator system of claim 17 , wherein:
the relative translation between the capstan and the one or more take-up pulleys comprises the capstan translating relative to a drive shaft that drives rotation of the capstan while the one or more take-up pulleys are translationally stationary relative to the drive shaft.

19. The manipulator system of claim 18 , further comprising:
a ball spline mechanism comprising the drive shaft and ball bearings between the drive shaft and the capstan,
wherein the drive shaft is a spline drive shaft, rotation of the spline drive shaft causes rotation of the capstan, and the capstan is translationally movable relative to the spline drive shaft.

20. The manipulator system of claim 17 , wherein:
the groove is a first groove spiraling helically around the outer surface of the capstan and the capstan mechanism further comprises a second groove spiraling helically around the outer surface of the capstan.

21. The manipulator system of claim 20 , wherein the cables comprise:
one or more first cables, each wound onto the capstan in a portion of the first groove, and
one or more second cables, each wound onto the capstan in a portion of the second groove.

22. The manipulator system of claim 21 , wherein:
the second cables are configured to experience less stress than the first cables.

23. The manipulator system of claim 22 , wherein:
one or more springs, each coupled in series with a corresponding one of the second cables.

24. The manipulator system of claim 17 , further comprising:
a track coupled to the first link; and
a carriage base movably coupled to the track and coupled to the instrument carriage, the one or more cables coupled to the carriage base to move the carriage base along the track.

Assignees

• Intuitive Surgical Operations

Inventors

• Lambrecht Bram Gilbert Antoon
• Cooper Thomas G
• Waterbury Andrew Cullen

Classifications

• B66D1/74

  Capstans · CPC title

• A61B34/71

  Manipulators operated by drive cable mechanisms · CPC title

• A61B34/30

  Surgical robots · CPC title

• A61B2034/715

  Cable tensioning mechanisms for removing slack · CPC title

• B66D1/7442

  having a horizontal rotation axis · CPC title