| abstract |
An ultrasonic device includes an electromechanical ultrasonic system defined by a predetermined resonant frequency, in which the system includes an ultrasonic transducer coupled to an ultrasonic blade. A method of estimating whether the state of an end effector of the ultrasonic device corresponds to open and unloaded; a tip bite; a tip bite on moist chamois; a full bite; a full bite on dry or moist chamois; or a staple in the jaw clamp, includes applying a drive signal defined by a magnitude and a frequency to the ultrasonic transducer, sweeping the frequency of the drive signal from below a first resonance to above the first resonance of the electromagnetic ultrasonic system, measuring and recording, impedance/admittance circle variables R e , G e , X e , and B e , comparing, the measured impedance/admittance circle variables R e , G e , X e , and B e to reference impedance/admittance circle variables R ref , G ref , X ref , and Bref, and determining, a state or condition of the end effector based on the result of the comparison. An electromechanical ultrasonic system may include a control circuit to effect the method. |