RATCHETING FOR MASTER ALIGNMENT OF A TELEOPERATED MINIMALLY INVASIVE SURGICAL INSTRUMENT

• US 20130245641A1
• Filed: 03/15/2013
• Published: 09/19/2013
• 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.
• Granted Patent: US 8,903,549 B2
• Time in Patent Office: Days
• US Class Current: 606/130
• 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 minimally-invasive surgical system comprising:

a slave surgical instrument having a slave surgical instrument tip wherein said slave surgical instrument tip has an alignment in a common coordinate frame of reference;

a master grip, coupled to said slave surgical instrument, having an alignment in said common coordinate frame of reference,

wherein an alignment error in said common frame of reference is a difference in alignment in said common frame of reference between said alignment of said slave surgical instrument tip and said alignment of said master grip; and

a ratcheting system, (i) coupled to said master grip to receive said alignment of said master grip and (ii) coupled to said slave surgical instrument, to control motion of said slave by continuously reducing the alignment error, as said master grip moves, without autonomous motion of said slave surgical instrument tip and without autonomous motion of said master grip.

2. The minimally-invasive surgical system of claim 1 wherein said alignment error is an orientation error.

3. The minimally-invasive surgical system of claim 2 wherein said orientation error comprises an angle.

4. The minimally-invasive surgical system of claim 3 where said 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)],

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

.

5. The minimally-invasive surgical system of claim 3 wherein said angle is one Euler angle in a set of Euler angles.

6. The minimally-invasive surgical system of claim 1, wherein said ratcheting system includes:

a roll-joint limit controller for determining whether motion of said slave surgical instrument tip has reached a joint limit wherein upon reaching said joint limit, motion of the slave surgical instrument tip is constrained.

7. The minimally-invasive surgical system of claim 1, wherein said ratcheting system includes:

an introduce control system error controller for introducing a control system error with respect to said alignments of said slave surgical instrument tip and said master grip.

8. The minimally-invasive surgical system of claim 1, wherein said ratcheting system includes:

a multiple orientation solution controller for determining an orientation solution closest to an orientation of said master grip.

9. The minimally-invasive surgical system of claim 1, wherein said master grip comprises an unpowered master grip.

10. A method for controlling alignment of a slave surgical instrument tip in a minimally-invasive surgical system with alignment of a master grip in said minimally-invasive surgical system comprising:

receiving, by a ratcheting system in said minimally-invasive surgical system, an alignment of said slave surgical instrument tip in a common frame of reference and an alignment of said master grip in said common frame of reference; and

ratcheting, by said ratcheting system, said alignment of said slave surgical instrument tip to said alignment of said master grip by continuously reducing an alignment error in said common frame of reference between said alignments, as said master grip moves, without autonomous motion of said slave surgical instrument tip and without autonomous motion of said master grip.

11. The method of claim 10 wherein said ratcheting further comprises:

moving said slave surgical instrument tip and said master grip in a same relative way upon engagement of following by said minimally-invasive surgical system irrespective of said alignments; and

bleeding off said alignment error by using a new alignment error in said common frame of reference when said motion of said master grip reduces said alignment error in said common frame of reference, and by using a current alignment error in said common frame of reference when said motion of said master grip does not reduces said alignment error thereby continuously reducing said alignment error between said alignments in said common frame of reference.

12. The method of claim 11 further comprising:

generating a new alignment in said common frame of reference for said slave surgical instrument using said new alignment error; and

sending a command to said slave surgical instrument based on said new alignment.

13. The method of claim 10 wherein said ratcheting further comprises:

generating a new alignment error in said common frame of reference between said alignment of said slave surgical instrument tip and said alignment of said master grip;

comparing said new alignment error with a current alignment error;

setting said current alignment error to said new alignment error, when said comparing shows said new alignment error is less than said current alignment error;

generating a new alignment for said slave surgical instrument tip in said common frame of reference using said current alignment error;

sending a command to said slave surgical instrument based on said new alignment; and

repeating said generating a new alignment error, said comparing, said setting, and said generating a new position, and said sending upon receipt of another alignment in said common frame of reference for said master grip.

14. The method of claim 10, wherein said ratcheting further comprises:

introducing a control system error between said slave surgical instrument tip alignment and said master grip alignment.

15. The method of claim 14, wherein said introducing a control system error further comprises:

penalizing a commanded angular velocity for said slave surgical instrument tip based on said current alignment error.

16. The method of claim 15, wherein said penalizing further comprises:

selecting an angular velocity scale factor from a continuous and monotonic angular velocity penalty profile based on said current alignment error wherein said angular velocity scale factor increases as said current alignment error decreases so that said angular velocity increases as said current alignment error decreases.

17. The method of claim 16, wherein said continuous and monotonic angular velocity penalty profile comprises a sigmoid function profile.

18. The method of claim 16 further comprising:

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

19. The method of claim 10 wherein said ratcheting further comprises:

selecting an orientation solution from a group of orientation solutions based on an orientation, in said common frame of reference, of said master grip.

20. The method of claim 10 wherein said ratcheting further comprises:

determining whether a joint limit in a given direction is reached; and

constraining motion of said slave upon reaching said joint limit.