A method of controlling the temperature of an ultrasonic blade between two temperature set points includes applying a first power level to an ultrasonic transducer to set an ultrasonic blade temperature to a first target temperature T1, monitoring a phase angle φ between voltage V.sub.g(t) and current I.sub.g(t) signals applied to the transducer, inferring the temperature of the blade based on the phase angle φ, determining that a transection process is complete, and applying a second power level to the transducer to set the blade temperature to a second target temperature T2. The transducer may be coupled to the blade via an ultrasonic waveguide. The first target temperature may be optimized for vessel sealing and the second target temperature may be optimized for clamp arm pad life. The control circuit may determine that transection is complete by determining that the ultrasonic blade contacts the clamp arm pad.

A surgical instrument includes a body assembly, a shaft assembly extending distally from the body assembly along a shaft axis, and an end effector at a distal end of the shaft assembly. The shaft assembly includes an outer tube configured to rotate relative to the body assembly about the shaft axis. The surgical instrument further includes a slip ring assembly configured to enable electrical communication between the shaft assembly and the body assembly while permitting relative rotation therebetween. The slip ring assembly includes a first electrical contact supported by the outer tube, and a second electrical contact electrically coupled with the first electrical contact and positioned radially outward of the outer tube. The first electrical contact is configured to rotate with the outer tube about the shaft axis relative to the second electrical contact while the first and second electrical contacts remain electrically coupled.

A surgical severing and stapling instrument, suitable for laparoscopic and endoscopic clinical procedures, clamps tissue within an end effector of an elongate channel pivotally opposed by an anvil. Various embodiments are configured to be operably attached to a robotic system to receive actuation/control motions therefrom.

A surgical severing and stapling instrument, suitable for laparoscopic and endoscopic clinical procedures, clamps tissue within an end effector of an elongate channel pivotally opposed by an anvil. Various embodiments are configured to be operably attached to a robotic system to receive actuation/control motions therefrom.

A surgical system is disclosed. The surgical system comprises a surgical end effector, a housing configured to operably interface with a source of rotary input motions, and a first rotary output member operably supported by the housing. The surgical system further comprises a second rotary output member operably supported by the housing, a knife bar supported for rotational and axial travel, and an axially movable closure member configured to apply closure and opening motions to the second jaw. The surgical system further comprises a knife bar interface, a first rotary control interface between the first rotary output member and the knife bar, and a second rotary control interface between the second rotary output member and the knife bar.

A surgical severing and stapling instrument, suitable for laparoscopic and endoscopic clinical procedures, clamps tissue within an end effector of an elongate channel pivotally opposed by an anvil. Various embodiments are configured to be operably attached to a robotic system to receive actuation/control motions therefrom.

An ultrasonic device may include an electromechanical ultrasonic system having a resonant frequency, the system including a transducer coupled to an ultrasonic blade. A method of driving the blade may include determining a tissue type contacting the blade, setting current delivered to the transducer to achieve a desired blade temperature, and setting a desired period during which the desired temperature is applied to the tissue. The tissue type may be determined by measuring an impedance of the transducer, comparing an impedance measurement data point to a reference data point, and classifying the impedance measurement data point based on a result of the comparison. Alternatively, the tissue type may be determined by applying a drive signal to the transducer, sweeping the frequency of the drive signal from below to above a resonance of the ultrasonic system, measuring and recording impedance/admittance variables, and comparing the measured variables to reference variables.

A method of determining an initial temperature of an ultrasonic blade may include measuring a resonant frequency of an ultrasonic blade prior to activating an ultrasonic transducer, in which the ultrasonic transducer is coupled to the blade via an ultrasonic waveguide, comparing the measured resonant frequency to a baseline resonant frequency, determining an initial temperature of the ultrasonic blade based on a difference between the measured resonant frequency and the baseline resonant frequency, and applying a power level to the blade based on the initial temperature of the blade. The method may further include applying a high power level to the transducer when the initial temperature of the ultrasonic blade is low or applying a low power level to the transducer when the initial temperature of the blade is high. The baseline resonant frequency may be stored in a memory look up table.

A surgical severing and stapling instrument, suitable for laparoscopic and endoscopic clinical procedures, clamps tissue within an end effector of an elongate channel pivotally opposed by an anvil. Various embodiments are configured to be operably attached to a robotic system to receive actuation/control motions therefrom.

A surgical tool configured for operation in connection with a robotic system. The surgical tool includes a shaft and an end effector extending distally from the shaft. The end effector comprises a first jaw member and a second jaw member movable relative to the first jaw member from a closed position to an open position in response to at least one axial motion. In addition, the surgical tool includes a motor configured to generate at least one rotational motion and a motion conversion assembly operably coupled to the motor and the second jaw member, wherein the motion conversion assembly is configured to convert the at least one rotational motion to the at least one axial motion.