Medical robotic system with dynamically adjustable slave manipulator characteristics

Patent metadata

Field	Value
Publication number	US-10820949-B2
Application number	US-84716807-A
Country	US
Kind code	B2
Filing date	Aug 29, 2007
Priority date	Apr 7, 1999
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

A slave manipulator manipulates a medical device in response to operator manipulation of an input device through joint control systems. The stiffness and strength of the slave manipulator are adjustable according to criteria such as the mode of operation of the slave manipulator, the functional type of the medical device currently being held by the slave manipulator, and the current phase of a medical procedure being performed using the slave manipulator by changing corresponding parameters of the control system. For safety purposes, such changes are not made until it is determined that it can be done in a smooth manner without causing jerking of the medical device. Further, an excessive force warning may be provided to surgery staff when excessive forces are being commanded on the slave manipulator for more than a specified period of time.

First claim

We claim:

1. A method implemented by a processor for dynamically adjusting a stiffness of a slave manipulator coupleable to a medical device, the method comprising:
the processor determining, during a medical procedure, whether the stiffness of the slave manipulator is to be adjusted by applying a set of expert rules stored in a memory, the set of expert rules using information of at least one of a functional type of the medical device and a current phase of the medical procedure; and
conditioned upon the processor determining that the stiffness of the slave manipulator is to be adjusted by applying the set of expert rules, the processor dynamically adjusting, during the medical procedure, the stiffness of the slave manipulator, by automatically changing a gain according to a value stored along with the set of expert rules in the memory, wherein the gain is used within a control system for controlling movement of the slave manipulator.

2. The method according to claim 1 , wherein the processor determining whether the stiffness is to be adjusted, comprises:
the processor determining that the stiffness is to be adjusted if the functional type of the medical device is one aiming at delivering a controlled mechanical energy to an anatomic structure of a patient and the current phase of the medical procedure involves such delivery of mechanical energy by the medical device.

3. The method according to claim 2 , wherein if the functional type of the medical device is of a first class of medical devices that deliver controlled mechanical energy to the anatomic structure, then the gain is to be adjusted so that induced movement of the medical device resulting from counter reactionary forces created during the delivery of mechanical energy to the anatomic structure is reduced.

4. The method according to claim 2 , wherein if the functional type of the medical device is of a second class of medical devices that aims at stabilizing the anatomic structure, then the gain is to be adjusted so that the medical device is allowed limited movement when contacting the anatomic structure.

5. The method according to claim 1 , wherein the processor determining whether the stiffness is to be adjusted, comprises:
the processor determining that the stiffness is to be adjusted if the functional type of the medical device is one where the medical device is to be guided through or around an anatomic structure of a patient and the current phase of the medical procedure involves such guidance of the medical device.

6. The method according to claim 5 , wherein the gain is to be adjusted so that induced movement of the medical device from external forces is reduced.

7. The method according to claim 1 , wherein the processor determining whether the stiffness is to be adjusted, comprises:
the processor determining that the stiffness is to be adjusted if the functional type of the medical device is one where the medical device is to control positioning of an anatomic structure in a patient and the current phase of the medical procedure involves such controlled positioning of the anatomic structure by the medical device.

8. The method according to claim 7 , wherein if the medical device is in the process of controlling the position of the anatomic structure in the patient, then the gain is to be adjusted so as resist movement of the medical device by externally applied forces.

9. The method according to claim 7 , wherein the functional type of the medical device is one that retracts and holds the anatomic structure during at least one phase of the medical procedure.

10. The method according to claim 7 , wherein the functional type of the medical device is one that stabilizes the anatomic structure during at least one phase of the medical procedure.

11. The method according to claim 1 , wherein the processor determining whether the stiffness is to be adjusted, comprises:
the processor determining that the stiffness is to be adjusted if the functional type of the medical device is for suturing and the current phase of the medical procedure involves such suturing using the medical device.

12. The method according to claim 1 , wherein the processor determining whether the stiffness is to be adjusted, comprises:
the processor determining that the stiffness is to be adjusted if the functional type of the medical device is one where the medical device is used for ultrasound surface scanning and the current phase of the medical procedure involves such ultrasound surface scanning using the medical device.

13. The method according to claim 1 , further comprising:
the processor identifying an operative mode of the slave manipulator;
wherein the criteria used for determining whether the stiffness is to be adjusted further includes the operative mode of the slave manipulator.

14. The method according to claim 13 , wherein the operative mode comprises a locked mode wherein the slave manipulator is non-responsive to operator manipulation of the master manipulator and is held in place, and an unlocked mode wherein the slave manipulator is responsive to operator manipulation of the master manipulator; and wherein the processor determining whether the stiffness of the first slave manipulator is to be adjusted depends upon whether the operative mode is in the locked mode or the unlocked mode.

15. The method according to claim 14 , wherein the gain is to be changed so that the stiffness of the slave manipulator in the locked mode is different than the stiffness of the slave manipulator in the unlocked mode.

16. The method according to claim 1 , further comprising:
the processor identifying the functional type of the medical device by electronically reading an identifier in a memory in the medical device.

17. The method according to claim 1 , further comprising:
the processor receiving an indication of the functional type of the medical device from a graphical user interface.

18. The method according to claim 1 , further comprising:
the processor receiving an indication of the current phase of the medical procedure from a graphical user interface.

19. The method according to claim 1 , further comprising:
the processor determining whether changing the gain would result in a motor command that exceeds a threshold value immediately following the changing the gain, wherein the motor command is generated by a first slave joint controller to drive a motor of the slave manipulator;
wherein the processor dynamically adjusting the stiffness of the slave manipulator comprises the processor changing the gain, which is used within the first slave joint controller, when the stiffness is to be adjusted and the motor command would not exceed the threshold value immediately following the changing the gain.

20. The method according to claim 19 , wherein the processor determining whether changing the gain would result in the motor command exceeding the threshold value immediately following the change in the gain comprises:
the processor determining the current motor command generated by the first slave joint controller using a current position error gain in the first slave joint controller;
the processor determining a prospective motor command to be generated within the first slave joint controller immediately following changing the gain, which is used within the first slave joint controller, by changing the current position error gain to a new position error gain in the first slave joint controller; and
the processor determining whether an absolute value of a difference betw

Assignees

• Prisco Giuseppe
• Stein Hubert
• Millman Paul
• Bailey David
• Nowlin William
• Ikeda Michael
• Nixon Thomas
• Intuitive Surgical Operations

Inventors

• Prisco Giuseppe
• Stein Hubert
• Millman Paul
• Bailey David
• Nowlin William
• Ikeda Michael
• Nixon Thomas

Classifications

• G05B2219/49144

  Limit movement on an axis by setting limits · CPC title

• G05B2219/40405

  Leader-follower position control · CPC title

• G05B2219/40146

  Telepresence, teletaction, sensor feedback from follower to operator · CPC title

• B25J9/1676

  Avoiding collision or forbidden zones · CPC title

• A61B34/30 Primary

  Surgical robots · CPC title