Ultrasound treatment appliance with automatic setpoint control

An ultrasound treatment appliance comprising:

• a surgical handpiece,
• an ultrasound insert,
• an ultrasound generator, and
• an electronic control circuit for controlling the ultrasound generator;
• wherein the handpiece includes a piezoelectric transducer including a distal portion having the ultrasound insert fastened thereto and a piezoelectric motor connected to the ultrasound generator and mechanically coupled to the distal portion,
• wherein the piezoelectric motor is arranged to transmit ultrasound waves to the insert,
• wherein said ultrasound waves are transmitted by the piezoelectric motor based on current and voltage setpoint signals delivered by the ultrasound generator to the piezoelectric motor,
• wherein the electronic control circuit is configured to:
• send the current and voltage setpoint signals to the transducer of the handpiece via cables, the current setpoint signal based on a speed of vibration of the piezoelectric motor and the voltage setpoint signal based on force required for the vibration of the piezoelectric motor;
• calculate a variation in frequency and impedance of a control signal in the piezoelectric transducer, the variation in the frequency being calculated between two consecutively measured mean values of the frequency of the control signal and the variation in the impedance being calculated between two consecutively measured mean values of the impedance of the ultrasound signal;
• compare the impedance variation of the ultrasound signal with a predetermined impedance variation value;
• compare the variation in the frequency of the ultrasound signal with a predetermined frequency variation value;
• automatically increase amplitudes of the current and voltage setpoint signals delivered by the ultrasound generator when the calculated variation in the impedance of the ultrasound signal is greater than the predetermined impedance variation value and when the calculated variation in the frequency of the ultrasound signal is greater than the predetermined frequency variation value;
• and
• automatically decrease the amplitudes of the current and voltage setpoint signals delivered by the ultrasound generator when the calculated variation in the impedance of the ultrasound signal is greater than the predetermined impedance variation value and when the calculated variation in the frequency of the ultrasound signal is less than the predetermined frequency variation value.