# US 10,864,011 B2 · System and method for driving an ultrasonic handpiece as a function of the mechanical impedance of the handpiece > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,864,011 B2 - Document ID: US10864011B2 - Status: Granted - Kind: B2 - Application number: 15/981,986 - Filed: 2018-05-17 - Published: 2018-09-20 - Granted: 2020-12-15 - Earliest claimed: 2013-08-07 - Assignees: Stryker Corporation - Applicants: Stryker Corporation - Inventors: Adam Downey; Matthew Owen - Web page: https://patentgrep.com/patent/US10864011B2 ## CPC - A61B 17/320068: {using mechanical vibrations, e.g. ultrasonic (A61B17/22012 takes precedence; dental tooth drilling devices operated by vibration A61C3/03; removing intra-ocular material using mechanical vibrations A61F9/00745)} - A61B 17/142: {with reciprocating saw blades, e.g. with cutting edges at the distal end of the saw blades} - A61B 2017/00017: {Electrical control of surgical instruments} - A61B 2017/0003: {of parts of the instruments} - A61B 2017/00977: {the depression depth determining the power rate} - A61B 2017/320069: {for ablating tissue} - A61B 2017/32007: {with suction or vacuum means} - A61B 2018/00648: {using more than one sensed parameter} - A61B 2018/0072: {Current} - A61B 2018/00732: {Frequency} - A61B 2018/00833: {Differential current} - A61B 2018/00892: {Voltage} - A61B 2018/00988: {Means for storing information, e.g. calibration constants, or for preventing excessive use, e.g. usage, service life counter} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract An ultrasonic surgical tool system for actuating a handpiece with a tip. The frequency of the drive signal applied to the handpiece drivers is a function of the equivalent of current through the mechanical components of the handpiece and tip and the frequency responsiveness of these components. ## Claims ### Claim 1 A system for vibrating the tip of an ultrasonic handpiece, the handpiece having at least one driver to which an AC drive signal is applied to vibrate the tip, the system including: a control console for generating the AC drive signal that is applied to the handpiece; a sensor for measuring a voltage of the AC drive signal; a sensor for measuring a current of the AC drive signal; and a processor coupled to the sensors for measuring the voltage and current of the AC drive signal and configured to: based on the voltage of the AC drive signal, the current of the AC drive signal, a frequency of the AC drive signal and a capacitance of the at least one driver, calculate a current applied to the at least one driver and an equivalent of current applied to the mechanical components of the handpiece; calculate a value based on the current applied to the at least one driver and the equivalent of current applied to the mechanical components of the handpiece; determine if the calculated value based on the current applied to the at least one driver and the equivalent of current applied to the mechanical components of the handpiece is substantially equal to a target value, the target value being based on a target frequency for the vibrations of the mechanical components of the handpiece; and adjust the frequency of the AC drive signal output by the control console if the calculated value is not substantially equal to the target value. ### Claim 2 (depends on 1) The system of claim 1, further comprising the handpiece having the at least one driver coupled to the control console. ### Claim 3 (depends on 1) The system of claim 1, wherein said processor is further configured to: obtain from a memory associated with the handpiece data representative of the capacitance of the at least one driver; and at least upon initial activation of said system: calculate the equivalent of current applied to the mechanical components of the handpiece based on the driver capacitance data obtained from the handpiece memory; and calculate the value based on the current applied to the at least one driver and the equivalent of current applied to the mechanical components of the handpiece based on the driver capacitance data read from the handpiece memory. ### Claim 4 (depends on 1) The system of claim 1, wherein said processor, by setting the frequency and voltage of the AC drive signal, is configured to determine the capacitance of the at least one driver of the handpiece. ### Claim 5 (depends on 1) The system of claim 1, wherein said processor is further configured to: after generating the calculated value based on the current applied to the at least one driver and the equivalent of current applied to the mechanical components of the handpiece, produce a modified value based on the calculated value, the frequency of the AC drive signal, and a target frequency; and based on the modified value, selectively set the frequency of the AC drive signal. ### Claim 6 (depends on 5) The system of claim 5, wherein said processor is configured to produce the modified value based on the calculated value and the difference between the frequency of the AC drive signal and the target frequency. ### Claim 7 (depends on 1) The system of claim 1, wherein the sensors for measuring the current and voltage are coils. ### Claim 8 A system for vibrating the tip of an ultrasonic handpiece, the handpiece having at least one driver to which an AC drive signal is applied to vibrate the tip, the system including: a control console for generating the AC drive signal that is applied to the handpiece; the handpiece having the at least one driver coupled to the control console to be energized by the AC drive signal; a processor internal to the control console and configured to: based on a voltage of the AC drive signal, a current of the AC drive signal, a frequency of the AC drive signal and a capacitance of the at least one driver, calculate a value, and based on the calculated value, set the frequency of the AC drive signal output by the control console; a power supply that outputs a signal at a constant frequency; and an amplifier coupled to the power supply that receives the signal output by said power supply and that is configured to amplify the signal from said power supply so as to output a variable frequency signal, wherein the processor is coupled to said amplifier to set the potential and frequency of the AC drive signal by regulating the frequency and amplitude of the signal output by said amplifier. ### Claim 9 (depends on 8) The system of claim 8, further comprising: a sensor for measuring the voltage of the AC drive signal; and a sensor for measuring the current of the AC drive signal. ### Claim 10 (depends on 8) The system of claim 8, wherein said processor is further configured to: based on the voltage of the AC drive signal, the current of the AC drive signal, the frequency of the AC drive signal and the capacitance of the at least one driver, calculate a current applied to the at least one driver and an equivalent of current applied to the mechanical components of the handpiece; calculate the value based on the current applied to the at least one driver and the equivalent of current applied to the mechanical components of the handpiece; after generating the calculated value based on the current applied to the at least one driver and the equivalent of current applied to the mechanical components of the handpiece, produce a modified value based on the calculated value, the frequency of the AC drive signal, and a target frequency; and based on the modified value, selectively set the frequency of the AC drive signal. ### Claim 11 A method of regulating the sourcing of an AC drive signal to an ultrasonic handpiece having a tip and at least one driver to which the AC drive signal is applied to vibrate the tip, said method including the steps of: sourcing an AC drive signal to the at least one driver, the AC drive signal having a potential and a frequency; measuring a voltage and a current of the AC drive signal; calculating a current applied to the at least one driver as a function of a capacitance of the at least one driver and the voltage and frequency of the AC drive signal; calculating an equivalent of current applied to the mechanical components of the handpiece by determining a difference between the current of the AC drive signal and the current applied to the at least one driver; calculating a value based on the current applied to the at least one driver and the equivalent of current applied to the mechanical components of the handpiece; based on the calculated value, setting the frequency of the AC drive signal; and supplying the AC drive signal to the handpiece having the at least one driver. ### Claim 12 (depends on 11) The method of claim 11, further comprising: setting the frequency of the AC drive signal based on a comparison between the calculated value and a target value; determining a target current for the mechanical components of the handpiece; comparing the target current to the calculated equivalent of current applied to the mechanical components of the handpiece; and based on said current comparison, adjusting the target value for a next comparison of the value calculated based on the current applied to the at least one driver and the equivalent of current applied to the mechanical components of the handpiece to the target value to set the frequency of the AC drive signal. ### Claim 13 (depends on 11) The method of claim 11, further comprising: obtaining from a memory associated with the handpiece data representative of the capacitance of the at least one driver; and at least upon initial activation of the ultrasonic handpiece: calculating the equivalent of current applied to mechanical components of the handpiece based on the driver capacitance data obtained from the handpiece memory; and calculating the value based on the current applied to the at least one driver and the equivalent of current applied to the mechanical components of the handpiece based on the driver capacitance data read from the handpiece memory. ### Claim 14 (depends on 11) The method of claim 11, further comprising: after generating the calculated value based on the current applied to the at least one driver and the equivalent of current applied to the mechanical components of the handpiece, producing a modified value based on the calculated value, the frequency of the AC drive signal, and a target frequency; and based on the modified value, selectively setting the frequency of the AC drive signal.