Surgical instrument with adjustable stop/start control during a firing motion
A surgical instrument. The surgical instrument includes an elongated channel configured to support a staple cartridge, an anvil pivotably connected to the elongated channel, a knife mechanically coupled to the staple cartridge, an electric motor mechanically coupled to the knife and a control circuit electrically connected to the electric motor. The control circuit is configured to ignore an occurrence of a first predefined event based on a position of the knife, automatically stop an advancement of the knife after an occurrence of a second predefined event, and automatically restart advancement of the knife after an occurrence of a third predefined event.
1. A surgical instrument, comprising:
an elongated channel configured to support a staple cartridge;
an anvil pivotably connected to the elongated channel;
a knife mechanically coupled to the staple cartridge;
an electric motor mechanically coupled to the knife, wherein the electric motor is configured to move the knife between a proximal position and a distal position; and
a control circuit electrically connected to the electric motor, wherein the control circuit is configured to:
determine a plurality of positions of the knife between the proximal position and the distal position; based on a longitudinal coordinate defined by any of the plurality of positions of the knife, selectively ignore an occurrence of a first predefined event;
automatically stop an advancement of the knife after an occurrence of a second predefined event; and
automatically restart the advancement of the knife after an occurrence of a third predefined event.
2. The surgical instrument of claim 1 , wherein the occurrence of the first predefined event comprises:
a change of a firing force over time exceeding a predetermined threshold; and
the firing force is below a first value.
3. The surgical instrument of claim 2 , wherein the control circuit comprises:
a first sensor configured to measure the firing force;
a second sensor configured to measure a position of the knife; and
a controller electrically connected to the first and second sensors and configured to determine the position of the knife and the change of the firing force over time.
4. The surgical instrument of claim 3 , wherein:
the first sensor comprises a strain gauge; and
the second sensor comprises a Hall-effect sensor.
5. The surgical instrument of claim 3 , wherein the occurrence of the second predefined event comprises:
the change of the firing force over time exceeding a second predetermined threshold; and
the firing force exceeds a second value, wherein the second value is greater than the first value.
6. The surgical instrument of claim 5 , wherein the third predefined event comprises at least one of the following:
a predefined drop in the firing force after the automatic stop of the advancement of the knife; and
a predefined period of time.
7. The surgical instrument of claim 6 , wherein the predefined drop in the firing force is at least one of the following:
a drop of a predefined percentage; and
a drop of a quantitative amount.
8. A surgical instrument, comprising:
an elongated channel configured to support a staple cartridge;
a knife mechanically coupled to the staple cartridge;
an electric motor mechanically coupled to the knife, wherein the electric motor is configured to move the knife between a proximal location and a distal location; and
a control circuit electrically connected to the electric motor, wherein the control circuit is configured to:
determine a plurality of positions of the knife between the proximal location and the distal location;
automatically stop an advancement of the knife upon an occurrence of a first predefined event;
automatically restart the advancement of the knife upon an occurrence of a second predefined event; and
based on a longitudinal coordinate defined by any of the plurality of positions of the knife, selectively ignore an occurrence of a third predefined event.
9. The surgical instrument of claim 8 , wherein the occurrence of the first predefined event comprises at least one of the following:
a firing force exceeding a predetermined threshold;
a change of a peak-to-peak firing force over time exceeding a second predetermined threshold;
the firing force exceeding the predetermined threshold and the change of the peak-to-peak firing force over time exceeding the second predetermined threshold; and
the firing force exceeding the predetermined threshold, the change of the peak-to-peak firing force over time exceeding the second predetermined threshold and the knife is within a predetermined range of positions between a proximal end of the staple cartridge and a distal end of the staple cartridge.
10. The surgical instrument of claim 9 , wherein the control circuit comprises:
a first sensor configured to measure the firing force;
a second sensor configured to measure a position of the knife; and
a controller electrically connected to the first and second sensors, wherein the controller is configured to determine:
the change of the peak-to-peak firing force over time; and
the position of the knife.
11. The surgical instrument of claim 10 , wherein:
the first sensor comprises a strain gauge; and
the second sensor comprises a Hall-effect sensor.
12. The surgical instrument of claim 9 , wherein the occurrence of the second predefined event is at least one of the following:
the knife being stopped for a period of time; and
a change of the firing force over time being within a predetermined range.
13. The surgical instrument of claim 12 , wherein the period of time varies based on a position of the knife.
14. A surgical instrument, comprising:
an elongated channel configured to support a staple cartridge;
an anvil pivotably connected to the elongated channel;
a knife mechanically coupled to the staple cartridge;
an electric motor mechanically coupled to the knife;
means for controlling the electric motor to:
determine a plurality of positions of the knife;
automatically stop an advancement of the knife based on a first threshold; and
automatically restart the advancement of the knife based on a second threshold; and
means for varying at least one of the first and second thresholds based on a longitudinal coordinate defined by any of the plurality of positions of the knife.
15. The surgical instrument of claim 14 , wherein the first threshold comprises at least one of the following:
a first value of a firing force;
a first value of a change of the firing force over time; and
a combination of the first value of the firing force and the first value of the change of the firing force over time.
16. The surgical instrument of claim 15 , wherein the second threshold comprises at least one of the following:
a second value of the firing force;
a second value of the change of the firing force over time;
a value of a change of a peak-to-peak firing force over time;
a combination of the second value of the firing force and the second value of the change of the firing force over time; and
a combination of the second value of the firing force and the value of the change of the peak-to-peak firing force over time.
17. The surgical instrument of claim 14 , wherein the means for controlling the electric motor comprise:
a first sensor configured to measure a force; and
a controller electrically connected to the first sensor.
18. The surgical instrument of claim 17 , further comprising means for determining a position of the knife.
19. The surgical instrument of claim 18 , wherein the means for determining the position of the knife comprise a Hall-effect sensor.