Method and system to sense relative partial-pose information using a shape sensor
A shape-sensing segment traverses through at least a portion of a kinematic chain of a tele-operated slave surgical instrument in a tele-operated minimally-invasive surgical system. The shape-sensing segment includes a pre-set perturbation. Shape information from the pre-set perturbation allows determination of relative partial-pose information for at least one link in the kinematic chain.
1. An apparatus comprising:
a kinematic chain comprising a proximal link and a distal link; and
a shape-sensing segment, extending between said proximal link and said distal link, having a mechanically-constrained permanent pre-set transition,
wherein the permanent pre-set transition is between a first position in said proximal link and a second position in said distal link, and
wherein the proximal link comprises a first axis,
wherein the first axis intersects the first position, and
wherein the second position is displaced from the first axis so that the second position is displaced axially from the first position.
2. The apparatus of claim 1 wherein said proximal link further comprises:
a body defining a first lumen extending through said proximal link, and said first lumen having the first axis wherein said shape-sensing segment passes through said first lumen.
3. The apparatus of claim 2 wherein said distal link further comprises:
a body defining a second lumen extending through said distal link, and said second lumen having a second axis,
wherein said shape-sensing segment passes into said second lumen to form said mechanically-constrained permanent pre-set transition between said distal link and said proximal link, and
wherein said second axis is offset from an axis of rotation.
4. The apparatus of claim 3 wherein said first axis is said axis of rotation.
5. The apparatus of claim 3 further comprising:
a roll joint mounted in said kinematic chain between said proximal link and said distal link so that said mechanically-constrained permanent pre-set transition passes through said roll joint.
6. The apparatus of claim 2 wherein said distal link further comprises:
a body defining a second lumen extending through said distal link, and said second lumen having a second axis,
wherein said shape-sensing segment passes into said second lumen to form an angle,
wherein said second axis is offset from an axis of rotation, and
wherein said mechanically-constrained permanent pre-set transition is said angle.
7. The apparatus of claim 6 wherein said first axis is said axis of rotation.
8. The apparatus of claim 6 further comprising:
a roll joint mounted in said kinematic chain between said proximal link and said distal link so that said angle is formed in said roll joint.
9. The apparatus of claim 1 further comprising:
an interrogator coupled to said shape-sensing segment; and
an electronic data processor, coupled to said interrogator to receive the shape information, to output relative partial-pose information for said proximal link and said distal link.
10. The apparatus of claim 9 , wherein
(a) said proximal link further comprises:
a body defining a first lumen extending through said proximal link, and having the first axis,
wherein said shape-sensing segment passes through said first lumen; and
(b) said distal link further comprises:
a body defining a second lumen extending through said distal link, and said second lumen having a second axis,
wherein said shape-sensing segment passes into said second lumen to form said mechanically-constrained permanent pre-set transition between said distal link and said proximal link, and
wherein said second axis is offset from an axis of rotation.
11. The apparatus of claim 10 wherein said relative partial-pose information for said proximal link and said distal link is determined by generating an x-y position of said shape-sensing segment in said second lumen.
12. The apparatus of claim 9 , wherein
(a) said proximal link further comprises:
a body defining a first lumen extending through said proximal link, and having the first axis,
wherein said shape-sensing segment passes through said first lumen; and
(b) said distal link further comprises:
a body defining a second lumen extending through said distal link, and said second lumen having a second axis,
wherein said shape-sensing segment passes into said second lumen to form an angle,
wherein said second axis is offset from an axis of rotation, and
wherein said mechanically-constrained permanent pre-set transition is said angle.
13. The apparatus of claim 12 , wherein said apparatus further comprises:
a clamp mounted on said shape-sensing segment to define said angle.
14. The apparatus of claim 12 wherein said relative partial-pose information for said proximal link and said distal link is determined by generating a pointing direction of said shape-sensing segment not parallel to said axis of rotation.
15. A method comprising:
receiving information from a mechanically-constrained permanent pre-set transition in a shape-sensing segment,
wherein said permanent pre-set transition is formed as said shape-sensing segment passes from a first position in a proximal link to a second position in a distal link in a kinematic chain of a surgical device,
wherein the proximal link comprises a first axis,
wherein the first axis intersects the first position, and
wherein the second position is displaced from the first axis so that the second position is displaced axially from the first position
generating, by a processor from said received information, relative partial-pose information for said proximal link and said distal link.
16. The method of claim 15 wherein said mechanically-constrained permanent pre-set transition comprises a transition between a first lumen extending along an axis of a body of said proximal link and a second lumen extending along an axis of a body of said distal link,
wherein the axis of the body of said proximal link is the first axis, and
wherein said axis of said body of said distal link is offset from an axis of rotation.
17. The method of claim 15 wherein said generating the relative partial-pose information for said proximal link and said distal link further comprises:
generating an x-y position of said shape-sensing segment in said second lumen.
18. The method of claim 15 wherein said mechanically-constrained permanent pre-set transition comprises an angle formed as said shape-sensing segment transitions from a first lumen extending along an axis of a body of said proximal link to a second lumen extending along an axis of a body of said distal link,
wherein the axis of the body of said proximal link is the first axis, and
wherein said axis of said body of said distal link is offset from an axis of rotation.
19. The method of claim 18 further comprising:
using a clamp on said shape-sensing segment to form said angle.
20. The method of claim 18 wherein said generating the relative partial-pose information for said proximal link and said distal link further comprises:
generating a pointing direction of said shape-sensing segment not parallel to said axis of rotation.