Powered surgical device with speed and current derivative motor shut off

• US 10,390,858 B2
• Filed: 04/05/2018
• Issued: 08/27/2019
• Est. Priority Date: 05/02/2017
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Evans, Christopher Kelly, Calderoni, Anthony
• Primary Examiner(s): Glass, Erick D
• Application Number:
  US15/946,327
• Publication Number:
  US 20180317964A1
• Time in Patent Office: 509 Days
• Field of Search: 318432
• CPC Class Codes: A61B 17/00234 for minimally invasive surgery A61B17/0218, A61B17/0469, A61B17/12013, A61B17/1285, A61B17/29, A61B17/320016 take precedence
• CPC Class Codes: A61B 17/072 for applying a row of staples in a single action , e.g. the staples being applied simultaneously
• CPC Class Codes: A61B 17/07207 the staples being applied sequentially
• CPC Class Codes: A61B 17/320016 Endoscopic cutting instruments, e.g. arthroscopes, resectoscopes A61B10/0233, A61B17/29, A61B17/3207 take precedence
• CPC Class Codes: A61B 17/3476 Powered trocars, e.g. electrosurgical cutting, lasers, powered knives
• CPC Class Codes: A61B 2017/00017 Electrical control of surgical instruments
• CPC Class Codes: A61B 2017/00039 Electric or electromagnetic phenomena other than conductivity, e.g. capacity, inductivity, Hall effect
• CPC Class Codes: A61B 2017/00075 Motion
• CPC Class Codes: A61B 2017/00123 and automatic shutdown
• CPC Class Codes: A61B 2017/00389 Button or wheel for performing multiple functions, e.g. rotation of shaft and end effector
• CPC Class Codes: A61B 2017/00398 using powered actuators, e.g. stepper motors, solenoids
• CPC Class Codes: A61B 2017/0046 with a releasable handle; with handle and operating part separable
• CPC Class Codes: A61B 2017/00464 for use with different instruments
• CPC Class Codes: A61B 2017/00477 Coupling A61B2017/0046 takes precedence
• CPC Class Codes: A61B 2017/00725 Calibration or performance testing
• CPC Class Codes: A61B 2017/00734 battery operated
• CPC Class Codes: A61B 90/03 Automatic limiting or abutting means, e.g. for safety

Abstract

A surgical instrument includes: an end effector; a power source; a motor coupled to the power source, the motor configured to actuate the end effector; and a controller operatively coupled to the motor and configured to control the motor based on a current draw of the motor and an angular velocity of the motor.

Claims

1. A surgical instrument, comprising:

an end effector;

a power source;

a motor coupled to the power source, the motor configured to actuate the end effector;

a motor control circuit configured to measure a current draw of the motor and an angular velocity of the motor; and

a controller operatively coupled to the motor and configured to;

control the motor based on a current draw of the motor and an angular velocity of the motor;

calculate an instantaneous rate of change of each of the current draw of the motor and the angular velocity of the motor; and

determine that the motor reached a mechanical limit based on the instantaneous rate of change of the current draw of the motor exceeding a first threshold and the instantaneous rate of change of the angular velocity of the motor exceeding a second threshold.

2. The surgical instrument according to claim 1, wherein the controller is configured to determine that the motor reached a mechanical limit based on the instantaneous rate of change of the current draw of the motor being positive and the instantaneous rate of change of the angular velocity of the motor being negative.

3. The surgical instrument according to claim 1, wherein the controller is configured to determine that the motor reached the mechanical limit based on the instantaneous rate of change of the current draw of the motor exceeding the first threshold concurrently with the instantaneous rate of change of the angular velocity of the motor exceeding the second threshold.

4. The surgical instrument according to claim 3, wherein the controller is configured to calibrate the motor based on the mechanical limit.

5. The surgical instrument according to claim 1, wherein the controller is configured to terminate a supply of electrical current to the motor from the power source in response to detection of the mechanical limit.

6. A method for controlling a surgical device, the method comprising:

energizing a motor to actuate an end effector;

measuring a current draw of the motor;

measuring an angular velocity of the motor;

controlling the motor based on the current draw of the motor and the angular velocity of the motor;

calculating an instantaneous rate of change of each of the current draw of the motor and the angular velocity of the motor; and

determining that the motor reached a mechanical limit based on the instantaneous rate of change of the current draw of the motor exceeding a first threshold and the instantaneous rate of change of the angular velocity of the motor exceeding a second threshold.

7. The method according to claim 6, further comprising:

determining that the motor reached a mechanical limit based on the instantaneous rate of change of the current draw of the motor being positive and the instantaneous rate of change of the angular velocity of the motor being negative.

8. The method according to claim 6, further comprising:

determining that the motor reached the mechanical limit based on the instantaneous rate of change of the current draw of the motor exceeding the first threshold concurrently with the instantaneous rate of change of the angular velocity of the motor exceeding the second threshold.

9. The method according to claim 8, further comprising:

calibrating the motor based on the mechanical limit.

10. The method according to claim 6, further comprising:

terminating a supply of electrical current to the motor from a power source in response to detection of the mechanical limit.

11. A method for calibrating a surgical instrument, the method comprising:

energizing a motor to actuate an end effector;

measuring a current draw of the motor;

measuring an angular velocity of the motor;

detecting the motor reaching a mechanical limit based on the current draw of the motor and the angular velocity of the motor; and

designating an angular position of the motor corresponding to the mechanical limit as a zero position for calibrating the motor.

12. The method according to claim 11, further comprising:

calculating an instantaneous rate of change of each of the current draw of the motor and the angular velocity of the motor.

13. The method according to claim 12, further comprising:

determining that the motor reached the mechanical limit based on the instantaneous rate of change of the current draw of the motor being positive and the instantaneous rate of change of the angular velocity of the motor being negative.

14. The method according to claim 12, further comprising:

determining that the motor reached the mechanical limit based on the instantaneous rate of change of the current draw of the motor exceeding a first threshold and the instantaneous rate of change of the angular velocity of the motor exceeding a second threshold.

15. The method according to claim 12, further comprising:

determining that the motor reached the mechanical limit based on the instantaneous rate of change of the current draw of the motor exceeding a first threshold concurrently with the instantaneous rate of change of the angular velocity of the motor exceeding a second threshold.