Systems and methods for controlling a surgical stapling and cutting instrument

Abstract

Various examples are directed to systems and methods for operating a surgical instrument comprising a firing member translatable proximally and distally along a longitudinal axis between a stroke begin position to a stroke end position distal of the stroke begin position; a knife coupled to the firing member; and a motor coupled to the firing member to translate the firing member between the stroke begin position and the stroke end position. A control circuit may receive a firing signal and begin a firing member stroke by providing an initial motor setting to the motor. The control circuit may maintain the initial motor setting for an open-loop portion of the firing member stroke. The control circuit may receive firing member motion data describing a motion of the firing member during the open-loop portion of the firing member stroke and may select a firing control program based at least in part on the motion of the firing member during the open-loop portion of the firing member stroke.

What is claimed is: 
     
         1 . A surgical instrument, comprising:
 an end effector;   a knife slidably receivable within the end effector;   a control circuit configured to:
 operate in an open-loop configuration to indirectly determine an amount of tissue positioned within the end effector based on a time required by the knife to traverse a first distance;
 determine that the knife has traversed the first distance; 
 determine the time required to traverse the first distance; and 
 operate in an closed-loop configuration to automatically advance the knife based on the time required to traverse the first distance. 
 
   
     
     
         2 . The surgical instrument of  claim 1 , comprising a firing member coupled to the knife. 
     
     
         3 . The surgical instrument of  claim 2 , comprising a motor coupled to the firing member to translate the firing member between a stroke begin position and a stroke end position. 
     
     
         4 . The surgical instrument of  claim 1 , further comprising a position sensor positioned to sense a position of the knife. 
     
     
         5 . The surgical instrument of  claim 1 , wherein advancing the knife comprises driving the knife at a constant speed. 
     
     
         6 . The surgical instrument of  claim 1 , wherein advancing the knife comprises driving the knife with a constant power. 
     
     
         7 . The surgical instrument of  claim 3 , wherein the amount of tissue positioned within the end effector determines the advancement of the knife from the end of the open-loop to the stroke end position. 
     
     
         8 . A surgical instrument, comprising:
 an end effector;   a knife slidably receivable within the end effector;   a control circuit configured to:
 operate in an open-loop configuration to indirectly determine an amount of tissue positioned within the end effector based on a time required by the knife to traverse a first distance
 determine that an initial time period has passed; 
 receive translation data describing a distal translation of the knife during the initial time period; and 
 operate in an closed-loop configuration to automatically advance the knife based on a distance of the distal translation of the knife during the initial time period. 
 
   
     
     
         9 . The surgical instrument of  claim 8 , comprising a firing member coupled to the knife. 
     
     
         10 . The surgical instrument of  claim 9 , comprising a motor coupled to the firing member to translate the firing member between a stroke begin position and a stroke end position. 
     
     
         11 . The surgical instrument of  claim 8 , further comprising a position sensor positioned to sense a position of the knife. 
     
     
         12 . The surgical instrument of  claim 8 , wherein advancing the knife comprises driving the knife at a constant speed. 
     
     
         13 . The surgical instrument of  claim 8 , wherein advancing the knife comprises driving the knife with a constant power. 
     
     
         14 . The surgical instrument of  claim 10 , wherein the amount of tissue positioned within the end effector determines the advancement of the knife from the end of the open-loop to the stroke end position. 
     
     
         15 . A surgical instrument, comprising:
 an end effector;   a knife slidably receivable within the end effector;   a control circuit configured to:
 operate in an open-loop configuration to indirectly determine an amount of tissue positioned within the end effector based on a time required by the knife to traverse a first distance 
 maintain an initial motor setting for the first distance; 
 determine that the knife has traversed the first distance; 
 determine the time required to traverse the first distance; and 
 operate in a closed-loop configuration to automatically advance the knife based on the time required to traverse the first distance. 
   
     
     
         16 . The surgical instrument of  claim 15 , comprising a firing member coupled to the knife. 
     
     
         17 . The surgical instrument of  claim 16 , comprising a motor coupled to the firing member to translate the firing member between a stroke begin position and a stroke end position. 
     
     
         18 . The surgical instrument of  claim 15 , further comprising a position sensor positioned to sense a position of the knife. 
     
     
         19 . The surgical instrument of  claim 15 , wherein advancing the knife comprises driving the knife at either a constant speed or a constant power. 
     
     
         20 . The surgical instrument of  claim 17 , wherein the amount of tissue positioned within the end effector determines the advancement of the knife from the end of the open-loop to the stroke end position.