Methods for driving an ultrasonic surgical instrument with modulator
View Patent ↗Methods for driving a surgical instrument are disclosed. The surgical instrument includes a transducer configured to produce vibrations along a longitudinal axis at a predetermined frequency. An end effector is adapted to couple to the transducer and extends along the longitudinal axis. The end effector includes a body having a proximal end and a distal end. The distal end is movable relative to the longitudinal axis by the vibrations produced by the transducer. A drive module is coupled to the transducer to generate a modulated drive signal. The distal end of the end effector is movable in response to the vibrations produced by the transducer in response to the modulated drive signal.
1. A method, comprising:
receiving a modulation waveform comprising a modulation amplitude (A m ) component and a modulation frequency (f m ) component; wherein the modulation waveform is defined by the following relationship:
S m =1+ A m ·sin (2 π·f m ·t );
generating a modulated drive signal with a drive module; and
coupling the modulated drive signal to a transducer, wherein the transducer is coupled to an end effector having a distal end;
wherein the distal end is movable in response to vibrations produced by the transducer in response to the modulated drive signal.
2. The method of claim 1 , comprising:
receiving a current set point signal at a first input of a modulator;
receiving the modulation waveform at a second input of the modulator;
generating a modulation signal by modulating the current set point signal with the modulation waveform; and
coupling the modulation signal with a current control loop to control the modulated drive signal coupled to the transducer.
3. The method of claim 2 ,
wherein receiving the modulation waveform comprises receiving a time varying modulation amplitude (A m ) component.
4. The method of claim 2 ,
wherein receiving the modulation waveform comprises receiving a time varying modulation frequency (f m ) component.
5. The method of claim 2 ,
wherein receiving the modulation waveform comprises receiving a time varying modulation amplitude (A m ) component and a time varying modulation frequency (f m ) component.
6. The method of claim 1 , comprising:
imparting a radiation pressure proportional to the modulated drive signal onto a fluid droplet particle in contact with the distal end of the end effector in response to the modulated drive signal.