Systems and Methods for Motor Torque Compensation

Patent metadata

Field	Value
Publication number	US-2016270779-A1
Application number	US-201514660282-A
Country	US
Kind code	A1
Filing date	Mar 17, 2015
Priority date	Mar 17, 2015
Publication date	Sep 22, 2016
Grant date	—

Abstract

A method includes receiving a torque limit for a motor, monitoring a torque output of the motor, determining an amplitude and a phase of a torque ripple of the torque output, and determining a compensated torque limit for the motor, the compensated torque limit including a first component at the torque limit and a second component at an adjusted torque limit.

First claim

What is claimed is:

1 . A method comprising:
receiving a torque limit for a motor; monitoring a torque output of the motor; determining an amplitude and a phase of a torque ripple of the torque output; and determining a compensated torque limit for the motor, the compensated torque limit including a first component at the torque limit and a second component at an adjusted torque limit.

2 . The method of claim 1 , wherein the adjusted torque limit is determined by adjusting the torque limit based on the determined amplitude and phase of the torque ripple.

3 . The method of claim 1 , wherein the compensated torque limit includes an alternating pattern of first and second durations.

4 . The method of claim 1 , wherein the torque limit is an upper torque limit.

5 . The method of claim 1 , wherein monitoring the torque output includes receiving information from a sensor associated with the motor.

6 . The method of claim 1 , further comprising outputting to a user interface, an indication of operation failure in response to determining that the torque output exceeds the compensated torque limit.

7 . The method of claim 1 , wherein the motor drives a stapler clamping mechanism.

8 . The method of claim 1 , wherein the motor is coupled to a drive system that includes a universal joint.

9 . A method comprising:
monitoring a torque output of a motor; receiving an upper torque limit for the motor; determining an oscillation component of the torque output, the oscillation component being associated with a torque ripple; adjusting the upper torque limit based on the determined oscillation component to create a locally compensated upper torque limit; and comparing the torque output to the locally compensated upper torque limit.

10 . The method of claim 9 , further comprising, outputting to a user interface, an indication of operation failure in response to determining that the torque output exceeds the locally compensated torque limit.

11 . The method of claim 9 , wherein the torque limit comprises an upper torque limit.

12 . The method of claim 9 , further comprising:
receiving a lower torque limit for the motor; adjusting the lower torque limit based on the determined oscillation component to create a locally compensated lower torque limit; and comparing the torque output to the locally compensated lower torque limit.

13 . The method of claim 9 , wherein adjusting the upper torque limit is based on the oscillation component.

14 . The method of claim 9 , wherein determining the oscillation component comprises determining an amplitude and a phase of the torque ripple.

15 . The method of claim 9 , wherein determining the oscillation component utilizes a Least Mean Squares (LSM) technique.

16 . The method of claim 9 , wherein the motor comprises a direct current (DC) brushless motor.

17 . The method of claim 9 , wherein the motor is used to drive a clamping mechanism of a medical staple instrument attached to a manipulator arm.

18 . The method of claim 17 , wherein the manipulator arm comprises a universal joint that transfers rotational force from the motor to the medical staple instrument.

19 . The method of claim 18 , wherein the oscillation component varies according to a position of the universal joint.

20 . The method of claim 9 , wherein the upper torque limit is based on a torque level that indicates that the clamping mechanism likely failed to clamp tissue as desired.

21 . A medical instrument system comprising:
a motor; and a control system comprising a processor and a memory, the memory comprising machine readable instructions that when executed by the processor, cause the control system to:
monitor a torque output of a motor;
determine an oscillation component of the torque output, the oscillation component being associated with a torque ripple;
receive an upper torque limit;
adjust the upper torque limit based on the oscillation component to create a localized compensated upper torque limit; and
output to a user interface, an indication of operation failure in response to a determination that the torque output exceeds the localized compensated upper torque limit.

22 . The system of claim 21 , further comprising:
a clamping mechanism; and a driveshaft that connects the motor to the clamping mechanism.

23 . The system of claim 22 , further comprising, a stapling mechanism integrated with the clamping mechanism, the stapling mechanism configured to staple tissue clamped by the clamping mechanism.

24 . The system of claim 22 , wherein the upper torque limit indicates a likely failure of the clamping mechanism.

25 . The system of claim 22 , wherein the driveshaft is connected to the clamping mechanism through use of at least one universal joint.

26 . The system of claim 25 , wherein the oscillation component is a function of a position of the universal joint.

27 . The system of claim 25 , wherein to account for the oscillation component, the control system is configured to adjust the upper torque limit in accordance with the oscillation component.

28 . A medical instrument system comprising:
a motor; and a control system comprising a processor and a memory, the memory comprising machine readable instructions that when executed by the processor, cause the control system to:
receive a motor torque limit for a motor;
monitor a torque output of the motor;
determine an amplitude and a phase of a torque ripple of the torque output; and
determine a locally compensated torque limit for the motor based on the torque ripple.

29 . The system of claim 28 , wherein the locally compensated torque limit include a first component at the torque limit and a second component at an adjusted torque limit.

30 . The system of claim 29 , wherein the locally compensated limit is determined by adjusting the motor torque limit based on the determined amplitude and phase of the torque ripple.

31 . The system of claim 28 , wherein the locally compensated torque limit includes an alternating pattern of first and second components.

32 . The system of claim 28 , wherein to monitor the torque output, the control system is further to receive information from a sensor regarding a position of the motor.

33 . The system of claim 28 , wherein the control system is further to output to a user interface an indication of operation failure in response to determining that the torque output exceeds the compensated torque limit.

39 . The system of claim 28 , wherein the motor drives a stapler clamping mechanism.

40 . The system of claim 28 , wherein the motor is coupled to a drive system that includes a universal joint.

41 . The system of claim 28 , wherein the motor torque limit is an upper motor torque limit.

Assignees

• Intuitive Surgical Operations

Inventors

• Chaghaerdi Amir
• Hingwe Pushkar

Classifications

• H02P6/10 Primary

  Arrangements for controlling torque ripple, e.g. providing reduced torque ripple · CPC title

• A61B17/068 Primary

  Surgical staplers {, e.g. containing multiple staples or clamps}({staplers containing only one staple A61B17/10; magazines or containers for staples A61B17/105;} for performing anastomosis A61B17/115; {staplers in general B25C5/00}) · CPC title

• G05B2219/45117

  Medical, radio surgery manipulator · CPC title

• G05B19/4062

  Monitoring servoloop, e.g. overload of servomotor, loss of feedback or reference · CPC title

• A61B2090/066

  for measuring torque · CPC title