Ratcheting for master alignment of a teleoperated minimally invasive surgical instrument

• US 8,903,549 B2
• Filed: 03/15/2013
• Issued: 12/02/2014
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Original Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Inventors: Itkowitz, Brandon D., DiMaio, Simon P., Nowlin, William C., Niemeyer, Gnter D., Mintz, David S.
• Primary Examiner(s): Holloway, Jason
• Assistant Examiner(s): Sample, Jonathan L
• Application Number:
  US13/839,438
• Publication Number:
  US 20130245641A1
• Time in Patent Office: 627 Days
• Field of Search: None
• US Class Current: 700/250
• CPC Class Codes: A61B 2017/00725 Calibration or performance testing
• CPC Class Codes: A61B 2034/305 Details of wrist mechanisms at distal ends of robotic arms
• CPC Class Codes: A61B 34/25 User interfaces for surgical systems
• 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 34/77 Manipulators with motion or force scaling
• CPC Class Codes: A61B 90/10 for stereotaxic surgery, e.g. frame-based stereotaxis
• CPC Class Codes: B25J 3/00 Manipulators of master-slave type, i.e. both controlling unit and controlled unit perform corresponding spatial movements
• CPC Class Codes: B25J 9/1669 characterised by special application, e.g. multi-arm co-operation, assembly, grasping
• CPC Class Codes: B25J 9/1689 Teleoperation
• CPC Class Codes: G05B 2219/45117 Medical, radio surgery manipulator
• CPC Class Codes: Y10S 901/27 Arm part
• CPC Class Codes: Y10S 901/41 Tool

Abstract

A minimally-invasive surgical system includes a slave surgical instrument having a slave surgical instrument tip and a master grip. The slave surgical instrument tip has an alignment in a common frame of reference and the master grip, which is coupled to the slave surgical instrument, has an alignment in the common frame of reference. An alignment error, in the common frame of reference, is a difference in alignment between the alignment of the slave surgical instrument tip and the alignment of the master grip. A ratcheting system (i) coupled to the master grip to receive the alignment of the master grip and (ii) coupled to the slave surgical instrument, to control motion of the slave by continuously reducing the alignment error, as the master grip moves, without autonomous motion of the slave surgical instrument tip and without autonomous motion of the master grip.

Claims

1. A surgical system comprising:

a slave surgical instrument having a slave instrument tip;

a master control; and

an alignment system coupled between the slave surgical instrument and the master control;

the alignment system having stored therein information characterizing a first alignment error, the first alignment error being a difference between an alignment of the slave instrument tip and a first alignment of the master control, the alignment of the slave instrument tip and the first alignment of the master control both being in a common frame of reference;

the alignment system being configured to determine a second alignment error, the second alignment error being a difference between the alignment of the slave instrument tip and a second alignment of the master control after movement of the master control from the first alignment of the master control to the second alignment of the master control, the second alignment of the master control being in the common frame of reference; and

the alignment system being configured to store information characterizing the second alignment error in place of the stored information characterizing the first alignment error only if the second alignment error is less than the first alignment error.

2. The surgical system of claim 1, the alignment system being configured to move the slave instrument tip in a same relative way as motion of the master control after the master control is engaged to control motion of the slave instrument, irrespective of the alignments of the slave instrument tip and the master control before the master control is engaged to control motion of the slave instrument.

3. The surgical system of claim 1, wherein the first alignment error is an orientation error.

4. The surgical system of claim 3, wherein the orientation error comprises an angle.

5. The surgical system of claim 4:

wherein the angle is expressed as;

θ

_e=cos<sup>−

1</sup>[0.5*(R<sub>Δ

11</sub>+R<sub>Δ

22</sub>+R<sub>Δ

33</sub>−

1)], and

wherein R<sub>Δ

11</sub>, R<sub>Δ

22</sub>, R<sub>Δ

33</sub> are diagonal elements of a relative rotation matrix R_Δ

.

6. The surgical system of claim 4, wherein the angle is one Euler angle in a set of Euler angles.

7. The surgical system of claim 1, the alignment system further comprising:

a roll-joint limit controller configured to determine whether motion of the slave instrument tip has reached a joint limit, wherein upon reaching the joint limit, motion of the slave instrument tip is constrained.

8. The surgical system of claim 1, the alignment system further comprising:

an introduce control system error controller configured to introduce a control system error with respect to the alignments of the slave instrument tip and the master control.

9. The surgical system of claim 1, the alignment system further comprising:

a multiple orientation solution controller configured to determine an orientation solution closest to an orientation of the master control.

10. The surgical system of claim 1, the master control comprising an unpowered master grip.

11. A method of operating a surgical system comprising:

storing, by a control system of the surgical system, information characterizing a first alignment error, the first alignment error being a difference between an alignment of a slave instrument tip and a first alignment of a master control, the alignment of the slave instrument tip and the first alignment of the master control both being in a common frame of reference;

determining, by the control system, a second alignment error, the second alignment error being a difference between the alignment of the slave instrument tip and a second alignment of the master control, the second alignment of the master control being after a movement of the master control from the first alignment of the master control to the second alignment of the master control, the second alignment of the master control being in the common frame of reference; and

storing, by the control system, information characterizing the second alignment error in place of the stored first alignment error only if the second alignment error is less than the first alignment error.

12. The method of claim 11, further comprising:

sending, by the control system, a command to move the slave instrument tip in a same relative way as motion of the master control after the master control is engaged to control motion of the slave instrument, irrespective of the alignments of the slave instrument tip and the master control before the master control is engaged to control motion of the slave instrument.

13. The method of claim 12, further comprising:

generating, by the control system, a new alignment in the common frame of reference for the slave instrument tip using the second alignment error; and

sending, by the control system, a command to move the slave instrument tip based on the new alignment.

14. The method of claim 11, further comprising:

comparing, by the control system, the second alignment error with the first alignment error;

generating, by the control system, a new alignment for the slave surgical instrument tip in the common frame of reference using the second alignment error, when the comparing shows the second alignment error is less than the first alignment error;

generating, by the control system, the new alignment for the slave surgical instrument tip in the common frame of reference using the first alignment error, when the comparing shows the second alignment error is greater than the first alignment error;

sending, by the control system, a command to move the slave instrument tip based on the new alignment.

15. The method of claim 11, further comprising:

introducing, by the control system, a control system error between the slave instrument tip alignment and the master control alignment.

16. The method of claim 15, the introducing a control system error further comprising:

penalizing, by the control system, a commanded angular velocity for the slave instrument based on one of the first alignment error and the second alignment error.

17. The method of claim 16, the penalizing further comprising:

selecting, by the control system, an angular velocity scale factor from a continuous and monotonic angular velocity penalty profile based on the one of the first alignment error and the second alignment error, wherein the angular velocity scale factor increases as alignment error decreases so that the angular velocity increases as the alignment error decreases.

18. The method of claim 17, the continuous and monotonic angular velocity penalty profile comprising a sigmoid function profile.

19. The method of claim 17, further comprising:

selecting the continuous and monotonic angular velocity penalty profile based on a surgeon using the surgical system.

20. The method of claim 11, further comprising:

selecting, by the control system, an orientation solution from a group of orientation solutions based on an orientation, in the common frame of reference, of the master control.

21. The method of claim 11, further comprising:

determining, by the control system, whether a joint limit in a given direction is reached; and

constraining, by the control system, motion of the slave instrument tip if the joint limit is reached.