FORCE SENSING FOR SURGICAL INSTRUMENTS

• US 20080065111A1
• Filed: 09/29/2007
• Published: 03/13/2008
• Est. Priority Date: 12/30/2005
• Status: Active Grant

• Current Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Original Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Inventors: Blumenkranz, Stephen, Larkin, David
• Granted Patent: US 8,375,808 B2
• Time in Patent Office: Days
• US Class Current: 606/130
• CPC Class Codes: A61B 17/3462 with means for changing the diameter or the orientation of the entrance port of the cannula, e.g. for use with different-sized instruments, reduction ports, adapter seals expandable cannulas A61B17/3417
• CPC Class Codes: A61B 2034/2061 using shape-sensors, e.g. fiber shape sensors with Bragg gratings
• CPC Class Codes: A61B 2034/305 Details of wrist mechanisms at distal ends of robotic arms
• CPC Class Codes: A61B 2090/064 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61B 34/30 Surgical robots
• CPC Class Codes: A61B 34/35 for telesurgery
• 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 34/76 Manipulators having means for providing feel, e.g. force or tactile feedback
• CPC Class Codes: B25J 15/0009 comprising multi-articulated fingers, e.g. resembling a human hand

Abstract

An apparatus, system, and method for improving force and torque sensing and feedback to the surgeon performing a telerobotic surgery are provided. In one embodiment, a surgical instrument, a robotic surgical system, a cannula, a cannula seal, and a method for improved sensing of z-axis forces on a robotic surgical instrument are disclosed.

Claims

1. A surgical instrument, comprising:

a housing portion that interfaces with a manipulator arm of a robotic surgical system;

a shaft including a lengthwise axis and an anti-friction outer surface;

a plurality of strain gauges on a distal end of the shaft;

a wrist joint operably coupled to the distal end of the shaft; and

an end effector operably coupled to the wrist joint.

2. The instrument of claim 1, wherein the anti-friction outer surface is a polyamide, an acetal, polytetrafluoroethylene (PTFE), or Parylene.

3. The instrument of claim 1, wherein the shaft includes a plurality of grooves along the lengthwise axis of the shaft for receiving the plurality of strain gauges and a cover over the grooves, wherein the cover provides the anti-friction outer surface.

4. The instrument of claim 3, wherein the cover is comprised of fluorinated ethylene propylene (FEP) or polytetrafluoroethylene (PTFE).

5. The instrument of claim 1, wherein the plurality of strain gauges includes eight strain gauges in two groups of four, with each of the strain gauges in a group being spaced apart by 90 degrees around the shaft.

6. The instrument of claim 1, wherein the plurality of strain gauges includes six strain gauges in two groups of three, with each of the strain gauges in a group being spaced apart by 120 degrees around the shaft.

7. The instrument of claim 1, wherein the plurality of strain gauges includes four strain gauges spaced apart by 90 degrees around the shaft.

8. The instrument of claim 1, wherein the plurality of strain gauges includes three strain gauges spaced apart by 120 degrees around the shaft.

9. The instrument of claim 1, wherein the plurality of strain gauges includes strain gauges spaced apart by 70 degrees and 110 degrees.

10. The instrument of claim 1, wherein the plurality of strain gauges is selected from the group consisting of fiber optic, foil resistive, surface acoustic wave, and semiconductor type strain gauges.

11. The instrument of claim 1, wherein a strain gauge is selected from the group consisting of a Fabry-Perot strain gauge and a fiber Bragg grating strain gauge.

12. The instrument of claim 1, wherein the plurality of strain gauges includes at least two fiber Bragg gratings along one fiber.

13. The instrument of claim 1, wherein the end portion of the surgical instrument is selected from the group consisting of jaws, scissors, graspers, needle holders, micro-dissectors, staple appliers, tackers, suction irrigation tools, clip appliers, cutting blades, cautery probes, irrigators, catheters, and suction orifices.

14. The instrument of claim 1, wherein the housing portion interfaces with a sterile adaptor of a sterile drape covering the manipulator arm.

15. The instrument of claim 1, further comprising a force sensor proximate the housing portion that senses an axial force along the lengthwise axis of the shaft.

16. A cannula, comprising:

a proximal portion that operably couples to an accessory clamp of a manipulator arm;

a tubular member positionable within body tissue, the tubular member having an opening therethrough for passage of an instrument shaft; and

an annular rib extending radially inward from an inner surface of the tubular member.

17. The cannula of claim 16, wherein the rib portion is axially positioned within the member to prevent contact between a force sensor on the instrument shaft and a distal end of the cannula.

18. The cannula of claim 16, wherein the annular rib includes an anti-friction interior surface.

19. The cannula of claim 18, wherein the anti-friction interior surface is comprised of an acetal, a polyetheretherketone (PEEK), a polyethylene terephthalate (PET), a polytetrafluoroethylene (PTFE), Parylene, a polyamide, or a polyethylene.

20. A cannula seal, comprising:

an annular elastomer member;

an aperture through the center of the elastomer member; and

a seal lip that protrudes toward the center of the aperture, wherein the seal lip is symmetric about a plane perpendicular to a lengthwise axis of the aperture to seal against an instrument shaft while providing a friction force which is not direction dependent.

21. The cannula seal of claim 20, wherein the seal lip includes an anti-friction surface.

22. The cannula seal of claim 21, wherein the anti-friction surface is comprised of Parylene.

23. The cannula seal of claim 20, further comprising an overhang portion that operably couples to a proximal end of a cannula.

24. The cannula seal of claim 20, further comprising a size adapter portion that fits into the aperture of the cannula seal to reduce a diameter of the aperture for an instrument pathway.

25. The cannula seal of claim 20, further comprising a plug on a flap over the aperture.

26. A robotic surgical system, comprising:

a manipulator assembly including a manipulator arm;

a surgical instrument operably coupled to the manipulator arm, the surgical instrument including;

a housing portion that interfaces with the manipulator arm of a robotic surgical system;

a shaft including a lengthwise axis and an anti-friction outer surface;

a plurality of strain gauges on a distal end of the shaft;

a wrist joint operably coupled to the distal end of the shaft; and

an end portion operably coupled to the wrist joint; and

a force sensor mounted on the manipulator assembly, the force sensor sensing an axial force along the lengthwise axis of the shaft.

27. The system of claim 26, further comprising a cannula, including:

a proximal portion that operably couples to an accessory clamp of a manipulator arm;

a tubular member positionable within body tissue, the tubular member having an opening therethrough for passage of an instrument shaft; and

an annular rib extending radially inward from an inner surface of the tubular member.

28. The system of claim 27, wherein the annular rib includes an interior anti-friction surface.

29. The system of claim 27, further comprising an annular seal within the proximal portion of the cannula, the seal having an anti-friction surface.

30. The system of claim 28, wherein the seal includes a lip portion that provides a friction force which is not direction dependent.

31. A method of sensing z-axis forces on a robotic surgical instrument, the method comprising:

providing a robotic surgical instrument including;

a housing portion for operably interfacing with a manipulator arm;

a shaft including a lengthwise axis and an anti-friction outer surface;

a wrist joint operably coupled to the distal end of the shaft; and

an end portion operably coupled to the wrist joint;

providing a cannula including;

a proximal portion for operable coupling to an accessory clamp of the manipulator arm;

a member positionable within body tissue, the member having an opening therethrough for passage of a shaft of the robotic surgical instrument; and

an annular rib within the member, the rib having an anti-friction surface;

operably coupling the housing portion of the surgical instrument to the manipulator arm;

passing the instrument shaft through the cannula; and

sensing the axial force along the lengthwise axis of the shaft using a force sensor proximate the housing portion.

32. The method of claim 31, further comprising positioning the annular rib to coincide with a position where the cannula passes through the body tissue.

33. The method of claim 31, further comprising mounting an annular seal having an anti-friction surface within the proximal portion of the cannula and passing the instrument shaft through the annular seal.

34. The method of claim 31, wherein the force sensor is mounted at an interface of the instrument housing with the manipulator arm.