Fixture for shape-sensing optical fiber in a kinematic chain

• US 8,182,158 B2
• Filed: 09/09/2010
• Issued: 05/22/2012
• Est. Priority Date: 06/30/2008
• Status: Active Grant

• Current Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Original Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Inventors: Rogers, Theodore W., Prisco, Giuseppe
• Primary Examiner(s): Peng, Charlie
• Assistant Examiner(s): Radkowski, Peter
• Application Number:
  US12/878,162
• Publication Number:
  US 20110044578A1
• Time in Patent Office: 621 Days
• Field of Search: 385/12, 385/66, 606/2, 606/4, 606/138
• US Class Current: 385/66
• CPC Class Codes: A61B 2034/2061 using shape-sensors, e.g. fiber shape sensors with Bragg gratings
• CPC Class Codes: A61B 34/30 Surgical robots
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: G01B 11/165 by means of a grating deformed by the object
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01D 5/35303 using a reference fibre, e.g. interferometric devices
• CPC Class Codes: G01D 5/35316 using a Bragg gratings
• CPC Class Codes: G01D 5/35377 Means for amplifying or modifying the measured quantity
• CPC Class Codes: G01M 11/083 by using an optical fiber in contact with the device under test [DUT]
• CPC Class Codes: G02B 6/022 using mechanical stress, e.g. tuning by compression or elongation, special geometrical shapes such as "dog-bone" or taper G02B6/02204 takes precedence; optical modulation using photo-elastic effect G02F1/0131
• CPC Class Codes: G02B 6/3616 Holders, macro size fixtures for mechanically holding or positioning fibres, e.g. on an optical bench supporting carriers of a microbench type G02B6/3648; micromanipulators B25J7/00; cassettes, bobbins G02B6/4439
• CPC Class Codes: G02B 6/3644 the coupling means being through-holes or wall apertures
• CPC Class Codes: G02B 6/38 having fibre to fibre mating means
• CPC Class Codes: Y10T 29/49826 Assembling or joining
• CPC Class Codes: Y10T 29/49838 by stringing
• CPC Class Codes: Y10T 29/49947 by applying separate fastener

Abstract

Localized strain is effectively eliminated in a shape sensing optical fiber where the fiber exits a link in a kinematic chain. In one aspect, the fiber is positioned in a channel within a fiber fixture portion of the link, and a surface of a lip of the channel is curved. The curved surface of the lip begins tangent to a wall of the channel and has a maximum radius of curvature that is less than the minimum bend radius that the fiber will experience during shape sensing. In another aspect, the fiber is positioned within a shape memory alloy tube that extends from the link.

Claims

1. An apparatus comprising:

a first link, a second link, and a joint coupled between the first and second links configured to permit relative articulation of the first link and the second link;

a shape memory alloy tube extending between the first link and the second link, the tube passing through an opening surrounded by a lip and extending from the first link into the joint; and

a shape-sensing optical fiber extending through the shape memory alloy tube, wherein the optical fiber comprises a length of fiber containing fiber Bragg gratings positioned adjacent the lip.

2. The apparatus of claim 1:

wherein the shape memory alloy comprises a Nickel/Titanium alloy.

7. The apparatus of claim 1:

wherein the shape memory alloy tube provides an effective minimum bend radius for the shape-sensing optical fiber of less than about 10 mm.

18. The apparatus of claim 1:

wherein a limit range of motion of the joint defines a minimum bend radius of the shape-sensing optical fiber, and wherein the shape memory alloy tube provides an effective minimum bend radius for the shape-sensing optical fiber that is larger than the defined minimum bend radius of the shape-sensing optical fiber.

3. A method comprising:

assembling a first link, a second link, and a joint coupled between the first and second links configured to permit relative articulation of the first link and the second link;

extending a shape memory alloy tube between the first link and the second link, wherein the tube passes through an opening surrounded by a lip and extending from the first link into the joint; and

positioning a shape-sensing optical fiber through the shape memory alloy tube, wherein the optical fiber comprises a length of fiber Bragg gratings positioned adjacent the lip.

4. The method of claim 3:

wherein the shape memory alloy comprises a Nickel/Titanium alloy.

5. The method of claim 3 further comprising:

constraining the optical fiber to slide longitudinally with reference to the first link.

6. The method of claim 3 further comprising:

constraining the optical fiber to be fixed with reference to the first link.

8. The method of claim 3:

wherein positioning the shape-sensing optical fiber through the shape memory alloy tube provides an effective minimum bend radius for the shape-sensing optical fiber of less than about 10 mm.

9. An apparatus comprising:

a first link, a second link, and a joint coupled between the first and second links and configured to permit relative articulation of the first link and the second link;

a tube extending between the first link and the second link, and passing through an opening surrounded by a lip and extending from the first link into the joint; and

a shape-sensing optical fiber extending through the tube,

wherein as the optical fiber bends, the tube distributes a force exerted by the lip along the optical fiber sufficient to avoid producing a region of local strain along a portion of the optical fiber that is adjacent the lip.

10. The apparatus of claim 9:

wherein the tube comprises a shape memory alloy.

11. The apparatus of claim 10:

wherein the shape memory alloy comprises a Nickel/Titanium alloy.

12. The apparatus of claim 9:

wherein the tube provides an effective minimum bend radius for the shape-sensing optical fiber of less than about 10 mm.

19. The apparatus of claim 9:

wherein a limit range of motion of the joint defines a minimum bend radius of the shape-sensing optical fiber, and wherein the tube provides an effective minimum bend radius for the shape-sensing optical fiber that is larger than the defined minimum bend radius of the shape-sensing optical fiber.

13. A method comprising:

articulating a first link and a second link relative to each other via a joint coupled between the first and second links;

sensing a position of the first link and the second link relative to each other via a shape-sensing optical fiber that extends between the first link and the second link, and passes through an opening defining a lip and extending from the first link into the joint; and

during bending of the optical fiber, distributing a force exerted by the lip along the optical fiber via a tube surrounding the optical fiber;

wherein the optical fiber comprises a length of fiber containing fiber Bragg gratings positioned adjacent the lip; and

wherein distributing the force exerted by the lip comprises distributing the force along the optical fiber to avoid producing a region of local strain in the length of fiber containing the fiber Bragg gratings.

14. The method of claim 13:

wherein the tube comprises a shape memory alloy.

15. The method of claim 13:

wherein the shape memory alloy comprises a Nickel/Titanium alloy.

16. The method of claim 13 further comprising:

constraining the optical fiber to slide longitudinally relative to the first link.

17. The method of claim 13 further comprising:

constraining the optical fiber to be fixed relative to the first link.