CLOSED LOOP FEEDBACK CONTROL OF MOTOR VELOCITY OF A SURGICAL STAPLING AND CUTTING INSTRUMENT BASED ON MEASURED TIME OVER A SPECIFIED NUMBER OF SHAFT ROTATIONS
A motorized surgical instrument is disclosed. The surgical instrument includes a displacement member configured to translate over a plurality of predefined zones. A motor comprising a shaft is coupled to the displacement member. A control circuit is coupled to the motor. A position sensor is coupled to the control circuit to monitor the rotation of the shaft. A timer circuit is coupled to the control circuit. The control circuit is configured to receive rotations of the shaft in a current zone defined by a set rotation interval, measure time at a set position of the rotation interval, wherein the measured time is defined as the time taken by the displacement member to traverse the rotation interval based on a predetermined number of shaft rotations, and set a command velocity of the displacement member for a subsequent zone based on the measured time in the current predefined zone.
