System and method for controlling ultrasonic tool

Abstract

To provide systems and methods for controlling an ultrasonic surgical tool.SOLUTION: Systems and methods of controlling an ultrasonic surgical tool 20 with a console 22 are provided. A first drive signal is applied to the ultrasonic surgical tool. A characteristic of a harmonic signal resulting from application of the first drive signal to the ultrasonic surgical tool is acquired. A cancellation signal is generated based on the characteristic of the harmonic signal. The first drive signal and the cancellation signal are combined to produce a second drive signal that is sinusoidal. The second drive signal is applied to the ultrasonic surgical tool such that presence of the harmonic signal resulting from application of the second drive signal is reduced relative to presence of the harmonic signal resulting from application of the first drive signal.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 192,838, filed on Jul. 15, 2015. The entire disclosure of this U.S. Provisional Patent Application is incorporated herein by reference and made a part of this specification.

[0002] The present invention generally relates to systems and methods for controlling ultrasonic surgical tools, and more particularly, to systems and methods for reducing the presence of unwanted signals generated by the operation of surgical tools.

Background Art

[0003] Ultrasonic surgical tools, such as ultrasonic aspirators, typically include an ultrasonic transducer and a handpiece connected to the transducer and having a tip that contacts tissue. A console or generator is connected to the surgical tool, and the surgical tool is controlled by outputting a specific drive signal to the transducer. The surgical tool is used in open or minimally invasive surgical procedures to coagulate tissue, etc.

[0004] In many tip - transducer combinations, the transducer is driven by a sine - wave drive signal having a certain frequency component. Ultrasonic tips are typically designed to operate at a frequency component having only a single dominant vibration mode (e.g., longitudinal mode).

[0005] The vibratory motion of the tip is referred to in the industry as mechanical current. ​​​​​​​​​​is directly related. When the machine current is in phase with the handpiece voltage, the tip is in a resonant state and operates. The transducer is driven by a sine wave signal having a certain frequency component , so the current to the handpiece is, as a result, a sine wave having a certain frequency component.

[0006] Depending on the combination of the conventional ultrasonic tip and handpiece, there are inevitably harmonic signals that cause harmonic distortion . Such harmonic signals may cause the current to the handpiece to exhibit a variable phase shift with respect to the voltage to the handpiece. In the conventional system, there is significant harmonic distortion in both the voltage and current to the handpiece . The harmonic signal causes the voltage and current to the handpiece to exhibit additional frequency components such as harmonics, whereby the waveforms of the voltage and current become distorted sine waves. Such harmonics cause undesirable vibrations at the tip. The undesirable vibrations have an adverse effect on the performance of the surgical tool . For example, such undesirable vibrations increase the stress on the tip and cause undesirable excessive heat at a certain location. Such undesirable excessive heat shortens the life of the tip due to fatigue and heating of the surrounding tissue. Furthermore, the system has to operate at a higher voltage to overcome the additional load effect of the acoustic characteristics of the tip that change due to the temperature rise caused by the excessive heat . Thereby, in turn, undesirable vibration energy is returned from the handpiece to the control console , resulting in a decrease in the performance of the console.

[0007]

Summary of the Invention

[0007] Accordingly, according to the present invention, the harmonics generated by driving an ultrasonic surgical tool A console is provided for controlling an ultrasonic surgical tool to reduce the presence of wave signals. This console is configured to apply a first drive signal to the ultrasonic surgical tool. This console acquires the characteristics of the harmonic signal generated by applying the first drive signal to the ultrasonic surgical tool. Based on the characteristics of the harmonic signal, this console generates a cancellation signal. This console combines the first drive signal and the cancellation signal to generate a second drive signal. The second drive signal is a sine wave. This console is configured to apply the second drive signal to the ultrasonic surgical tool such that the presence of the harmonic signal generated by the application of the second drive signal is reduced compared to the presence of the harmonic signal generated by the application of the first drive signal.

[0008] Also, according to the present invention, a method for controlling an ultrasonic surgical tool to reduce the presence of harmonic signals generated by driving the ultrasonic surgical tool is provided. This method includes driving the ultrasonic surgical tool with a first drive signal. The characteristics of the harmonic signal generated by driving the ultrasonic surgical tool with the first drive signal are acquired. This method includes generating a cancellation signal based on the characteristics of the harmonic signal. The first drive signal and the cancellation signal are combined to generate a second drive signal. The second drive signal is a sine wave. This method includes driving the ultrasonic surgical tool with the second drive signal such that the presence of the harmonic signal generated by driving the ultrasonic surgical tool with the second drive signal is reduced compared to the presence of the harmonic signal generated by driving the ultrasonic surgical tool with the first drive signal.

[0009] ​​​​​ Furthermore, according to the present invention, a method for controlling an ultrasonic surgical tool is provided to reduce the presence of harmonic signals. The harmonic signals include frequency, phase, and amplitude. The method includes driving the ultrasonic surgical tool with a first drive signal, obtaining the characteristics of the harmonic signals resulting from driving the ultrasonic surgical tool with the first drive signal, and generating a cancellation signal having a frequency similar to the frequency of the harmonic signals, a phase shifted by 180 degrees in relation to the phase of the harmonic signals, and an amplitude greater than that of the harmonic signals. The method further includes outputting a second drive signal for driving the ultrasonic surgical tool. The second drive signal is a sine wave and is based on the combination of the first drive signal and the cancellation signal.

[0010] Advantageously, the present system and method can reduce the presence of harmonic signals, thereby reducing the harmonic distortion resulting from the vibration of the surgical tool. By reducing the presence of harmonic signals, the present system and method can effectively reduce the impedance of the surgical tool, i.e., the combination of the handpiece and the tip, the power and voltage required to maintain the specific vibration displacement of the tip, the heating of the tip, the energy returned to the console, and / or unwanted (e.g., harmonic) vibration frequencies. These changes can improve the tissue resection performance of the surgical tool.

[0011] Furthermore, by reducing the adverse effects of harmonic signals, the present system and method enhance the versatility of using various types and shapes of ultrasonic tools and tips that exhibit harmonic distortion in many cases. The present system and method further improve the cutting performance by Enable simultaneous control (e.g., two-mode control) of different resonance modes.

[0012] After reading the following description, the understanding of the present invention will progress, and other features and advantages of the present invention will be easily recognized.

Brief Description of the Drawings

[0013]

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DETAILED DESCRIPTION OF THE INVENTION

[0014] I. System Overview Referring to the figures, like numerals are used throughout several figures to indicate like or corresponding parts, and aspects of a system 10 and a method 12 for controlling an ultrasonic surgical tool 20 are shown throughout to reduce the presence of harmonic signals resulting from driving the ultrasonic surgical tool 20. As shown in FIG. 1, the system 10 includes an ultrasonic surgical tool 20 and an ultrasonic surgical tool tool 20.

[0015] It has a console 22 for controlling the surgical tool 20. The surgical tool 20 is connected to the console 2 2. Examples of the surgical tool 20 include, but are not limited to, medical devices, including, but not limited to, ultrasonic aspirators, ultrasonic sealers, ultrasonic cutters, etc.

[0016] The surgical tool 20 has a handpiece 21. As shown in FIG. 2, a transducer 24 is housed within the handpiece 21 . The transducer 24 can be any suitable element or configuration, such as a piezoelectric ceramic element, suitable for converting electrical energy into mechanical energy . The surgical tool 20 further has a tip 26 having a distal end configured to engage tissue. Examples of engagement with tissue include cutting and / or sealing of tissue . The tip 26 can be connected to the transducer 24 .

[0017] The surgical tool 20 can utilize various interchangeable tips 26. The tip 26 can be permanently or removably fixed to the handpiece 21. The tip 26 can have any suitable function and configuration, and can include, for example, tips for soft tissue resection and tips for fine bone dissection . Preferred examples of the tip 26 include, but are not limited to, Stryker(™) Straight(™), Stryker(™) Barracuda(™) for soft tissue, and Stryker(™) Claw(™), Stryker(™) Knife(™), Stryker(™) Payner(™) for hard tissue .

[0018] ​​​​​​​In one embodiment, the console 22 includes a memory 28, a controller 30, and an amplifier 32. The memory 28 is configured to store relevant data for controlling the surgical tool 20. The memory 28 can be any suitable type of memory such as non-volatile memory, ROM, EEPROM, RAM, flash memory, etc. The console 22 can have any suitable firmware or software stored in the memory 28 to assist in controlling the surgical tool 20. The controller 30 is connected to the memory 28. The controller 30 can include one or more processors for executing instructions stored in the memory 28. The controller 30 communicates with an amplifier 32 for outputting signals to the surgical tool 20. The amplifier 32 is a linear amplifier in one embodiment.

[0019] The controller 30 can communicate with a sampling module 34, a signal generation unit 36, and a signal synthesis unit 38. In FIG. 2, the sampling module 34, the signal generation unit 36, and the signal synthesis unit 38 are part of the controller 30 or are configured integrally with the controller 30. Alternatively, any one or a combination of the sampling module 34, the signal generation unit 36, and the signal synthesis unit 38 can be provided physically external to the controller 30 so as to be physically independent of the controller 30. Furthermore, in some cases, any one of the sampling module 34, the signal generation unit 36, and the signal synthesis unit 38 can be combined so as to be integrally configured by the same component or implemented by the same software. The sampling module 34 is a fast Fourier ​It can communicate with the transformation (FFT) module 37 and can include the fast Fourier transform (FFT) module 37. It can include the fast Fourier transform (FFT) module 37.

[0020] Any of the sampling module 34, the signal generation unit 36, the FFT module 37, and the signal synthesis unit 38 can include executable instructions. These executable instructions are stored in the memory 28 of the console 22 to be executed by one or more processors. The functions of the sampling module 34, the signal generation unit 36, the FFT module 37, and the signal synthesis unit 38 will be described in detail below. It is stored in the memory 28 of the console 22 to be executed by one or more processors. The functions of the sampling module 34, the signal generation unit 36, the FFT module 37, and the signal synthesis unit 38 will be described in detail below. It will be described in detail below.

[0021] II. The First Driving Signal and the Harmonic Signal The console 22 is configured to apply a first driving signal 40 to the ultrasonic surgical tool 20, more specifically to the transducer 24. The transducer 24 converts the electrical energy of the first driving signal 40 into mechanical energy. The first driving signal 40 is output from the amplifier 32 within the console 22 that amplifies the first driving signal 40. The first driving signal 40 is at a low voltage. For example, the voltage of the first driving signal 40 is 0VAC to 100VAC, more specifically 0VAC to 10VAC, and even more specifically 0VAC to 5VAC. The amplifier 32 amplifies the voltage of the first driving signal 40 up to 1000VAC as needed to maintain the desired mechanical current. The console 22 of the surgical tool 20 can include any suitable switch or button that allows the operator to selectively control the first driving signal 40. The first driving signal 40 is at a low voltage. For example, the voltage of the first driving signal 40 is 0VAC to 100VAC, more specifically 0VAC to 10VAC, and even more specifically 0VAC to 5VAC. The amplifier 32 amplifies the voltage of the first driving signal 40 up to 1000VAC as needed to maintain the desired mechanical current. The console 22 of the surgical tool 20 can include any suitable switch or button that allows the operator to selectively control the first driving signal 40. The console 22 of the surgical tool 20 can include any suitable switch or button that allows the operator to selectively control the first driving signal 40. It can include any suitable switch or button that allows the operator to selectively control the first driving signal 40.

[0022] FIG. 3 shows an example of the first driving signal 40 for one particular handpiece 21. The handpiece 21 has a sharp angle joint and a micro straight tip portion 26. The micro straight tip portion 26 is driven by a voltage sine wave drive signal of 25.5 kHz in air at a mechanical current of 80 mA. Specifically, FIG. 3 shows the voltage output of the first drive signal 40. The first drive signal 40 has a sine waveform. In other words, the first drive signal 40 has a waveform showing smooth repetitive vibration. Therefore, the first drive signal 40 is not a pulse wave or a rectangular wave. The sinusoidality of the waveform of the first drive signal 40 is important for imparting ultrasonic vibration into the tip portion 26. The sine waveform of the first drive signal 40 includes frequency components related to the wavelength λ1 of the first drive signal 40. Those frequency components are components of the fundamental (first harmonic) drive frequency 41. The component of the fundamental drive frequency 41 may also be known as the desired resonance frequency. In this example, the component of the fundamental drive frequency 41 is 25.5 kHz. The component of the fundamental drive frequency 41 can be any suitable frequency, including, for example, frequencies in the range of 25 kHz to 55 kHz, as will be recognized by those skilled in the art. The first drive signal 40 further has a phase "P1" and an amplitude "a1". The console 22 is configured to generate the first drive signal 40 using the signal generation unit 36.

[0023] The first drive signal 40 includes several characteristics. The characteristics of the first drive signal 40 generally relate to the waveform of the first drive signal 40. Any characteristic of the first drive signal 40 can be a characteristic based on the time domain or the frequency domain. For example, with respect to the time domain as shown in FIG. 3 Then, the characteristics of the first drive signal 40 can include at least one of the wavelength λ1, the phase "P1", and the amplitude "a1". In the following frequency domain as shown in FIGS. 6 and 7, for example, the characteristics of the first drive signal 40 can include at least one of the frequency, magnitude, and phase of the first drive signal 40. For example, the frequency is a component of the basic drive frequency 41. The characteristics of the first drive signal 40 may be determined in advance or may be known. Alternatively, the characteristics of the first drive signal 40 may be measured. For example, the characteristics of the first drive signal 40 can be derived from the measured values of the current or voltage associated with applying the first drive signal 40 as described below. Those skilled in the art will recognize that any characteristic of the first drive signal 40 can be derived individually or in combination from the parameters in the time domain and the parameters in the frequency domain. FIG. 4 shows an example of an electromechanical circuit model of a combination of the handpiece 21 and the tip 26. In FIG. 4, V is the output drive voltage (voltage source) from the console 22. In the following, the output drive voltage is also referred to as the handpiece voltage V In FIG. 4, R is the series resistance of the console. The current flowing through R is the supply source current i and is also referred to as the handpiece current i in the following. The handpiece current i can be determined by the impedance of the handpiece 21. This impedance can be derived from one or more characteristics of the handpiece 21. For example, the impedance is the negative of the tip 26 It will be recognized by those skilled in the art that any characteristic of the first drive signal 40 can be derived individually or in combination from the parameters in the time domain and the parameters in the frequency domain.

[0024] FIG. 4 shows an example of an electromechanical circuit model of a combination of the handpiece 21 and the tip 26. In FIG. 4, V S is the output drive voltage (voltage source) from the console 22. Hereinafter, the output drive voltage is also called the handpiece voltage V In the following, the output drive voltage is also called the handpiece voltage V HP In FIG. 4, R S is the series resistance of the console. R S The current flowing through is the supply source current i S and is also called the handpiece current i in the following. HP The handpiece current i HP can be determined by the impedance of the handpiece 21. This impedance can be derived from one or more characteristics of the handpiece 21. For example, the impedance can be derived from one or more characteristics of the handpiece 21. For example, the impedance is the negative of the tip 26 The load, the acoustic characteristics of the handpiece 21, the acoustic characteristics of the tissue to be excised, the characteristics of the transducer 24, the vibration of the handpiece 21, etc.

[0025] As shown in FIG. 4, the capacitance of the static handpiece is C o , and the current flowing through the static capacitance C o is i co . The vibration resonance mode is represented by a series of R m , L m and C m . However, i m represents the desired mechanical current. The desired mechanical current i m is induced by the load applied to the handpiece 21. The vibration motion of the tip 26 is directly related to the desired mechanical current i m . The displacement due to the vibration of the tip 26 increases as the mechanical current i m increases. The tip 26 operates in a resonant state when the desired mechanical current i is in phase with the handpiece voltage V m HP . is in phase. when

[0026] The model in FIG. 4 is based on the standard Butterworth-VanDyke model , but is improved by taking into account the general component X and its influence on the model. The general component X is a theoretical component that generates the harmonic signal 44 by applying the first drive signal 40 to the combination of the surgical tool 20, more specifically, the handpiece 2 1 and the tip 26. The harmonic signal 44 can include any higher-order harmonic, such as the second harmonic, third harmonic, or fourth harmonic, etc. of the components of the fundamental drive frequency 41, or any combination thereof. Since the harmonic signal 44 is the cause of harmonic distortion, by applying the first drive signal 40 to the combination of the handpiece 21 and the tip 26. The harmonic signal 44 can include any higher-order harmonic, such as the second harmonic, third harmonic, or fourth harmonic, etc. of the components of the fundamental drive frequency 41, or any combination thereof. Since the harmonic signal 44 is the cause of harmonic distortion, which generates the harmonic signal 44 including any higher-order harmonic such as the second harmonic, third harmonic, or fourth harmonic of the components of the fundamental drive frequency 41, or any combination thereof. Since the harmonic signal 44 is the cause of harmonic distortion, it is It is a generally undesirable signal. In the following, the frequency of the harmonic signal 44 is referred to as the harmonic frequency component 43. The harmonic signal 44 may necessarily occur based on a specific combination of the handpiece 21 and the tip 26. In some cases, the harmonic signal 44 does not appear until the minimum threshold displacement of the tip 26 is made. Such behavior is regarded as non-linear behavior . The current i flowing through the general component X represents an undesirable mechanical current. x In some versions of the model, the general component X can be determined by the desired mechanical current i m or can be a vibration current source related to the desired mechanical current i . m

[0027] Fig. 5 shows the waveforms of the handpiece current i and the handpiece voltage V HP before applying the harmonic cancellation method 12 described in this specification, and an exemplary effect of the harmonic signal 44 on the waveforms of the handpiece current i HP and the handpiece voltage V HP . The first driving signal 40 is a sine wave and has a certain signal frequency component, so the handpiece current i HP and the handpiece voltage V are consequently sine waves and have a certain signal frequency component H P . In this case, since the component of the fundamental driving frequency 41 is accompanied by the component of the harmonic frequency 43, the waveform of the handpiece current i HP shows a variable phase shift φ with respect to the handpiece voltage V . The handpiece current i and the handpiece voltage V HP show a plurality of frequency components HP . The handpiece current i HP and the handpiece voltage V HP The waveform is not a pure sine wave. The handpiece current i HP and the handpiece voltage V HP differ, in particular, according to the specific tip 26 used.

[0028] Figures 6 and 7 show the respective fast Fourier transforms of the handpiece voltage V HP and the handpiece current i HP in Fig. 5. This analysis identifies one or more frequencies that are the most significant cause of the observed distortion, as shown in Fig. 5. In this example, FFT analysis reveals that the component at the fundamental drive frequency 41 (i.e., 25.5 kHz z) is accompanied by the component at the additional harmonic frequency 43 of the harmonic signal 44 (e.g., 51 kHz). The harmonic signal 44 is the cause of the resulting harmonic distortion. In the case of the handpiece voltage V HP , the component at the harmonic frequency 43 exceeds 40% of the magnitude of the component at the fundamental drive frequency 41. In the case of the handpiece current i HP , the component at the harmonic frequency 43 has a magnitude exceeding 90% of the magnitude of the component at the fundamental drive frequency 41. It should be understood that Figs. 6 and 7 show an example of the component at the harmonic frequency 43. Therefore, the component at the harmonic frequency 43 may be different from the harmonic frequencies in Figs. 6 and 7 and may have a different magnitude. HP 43 and may have a different magnitude. Figs. 6 and 7 show an example of the component at the harmonic frequency 43. Therefore, the component at the harmonic frequency 43 may be different from the harmonic frequencies in Figs. 6 and 7 and may have a different magnitude. It should be understood that Figs. 6 and 7 show an example of the component at the harmonic frequency 43. Therefore, the component at the harmonic frequency 43 may be different from the harmonic frequencies in Figs. 6 and 7 and may have a different magnitude. When further analyzing the data, it becomes clear that the phase angle θ between the harmonic signals 44 in the waveforms of the handpiece voltage V

[0029] and the handpiece current i HP is 103 degrees. This phase angle HP θ is greater than 90 degrees, which gives a negative power factor, (the console being 51k and the handpiece current i θ is greater than 90 degrees, which gives a negative power factor, (the console being 51k (Instead of generating power at Hz), the combination of the handpiece 21 and the tip 26 is shown to generate power at 51 kHz. In this case, the 25.5 kHz vibration is due to the nonlinear vibration behavior of the combination of the handpiece 21 and the tip 26, which induces a 51 kHz vibration. The 51 kHz vibration moves the piezoelectric element in the transducer 24, thereby converting a part of the mechanical energy into 51 kHz electrical energy, that is, the component of the high harmonic frequency 43.

[0030] Figure 8 shows the respective contributions of the component of the fundamental drive frequency 41 and the component of the harmonic frequency 43 to the current in each o branch of the circuit of Figure 4. This contribution is based on the assumption that R m has a low value and the series impedance of R, L, C m , L m , C m has a relatively high impedance at the component of the harmonic frequency 4 3. In Figure 8, the component of the fundamental drive frequency 41 and the component of the harmonic frequency 43 each contribute significantly to the handpiece current i HP . The component of the fundamental drive frequency 41 contributes significantly to o the current i flowing through the static capacitance C and the desired mechanical current i co . In contrast, the component of the harmonic frequency m 43 does not substantially contribute to the current i flowing through the static capacitance and the desired mechanical current i co . Furthermore, with respect to the undesired mechanical current i m , the component of the fundamental drive frequency 41 substantially does not contribute, while the component of the harmonic frequency 43 x contributes significantly. Therefore ​, According to this model, the handpiece current i HP The harmonic signal 44 existing within is the general undesirable mechanical current i flowing through component X x is directly related to the existence of.

[0031] III. Reduction of the Second Drive Signal and Harmonic Signal The system 10 and method 12 reduce the presence of the harmonic signal 44 described above. As shown in FIG. 9, the method 12 can include applying a first drive signal 40 to the ultrasonic tool 20 in step 200. In step 202, at least one characteristic of the harmonic signal 44 generated by applying the first drive signal 40 to the ultrasonic surgical tool 20 is obtained. In step 206, based on the characteristics of the obtained harmonic signal 44, a cancellation signal 70 is generated. In step 208, the console 22 combines the first drive signal 40 and the cancellation signal 70 to generate a second drive signal 80. The second drive signal 80 is a sine wave. In step 210, the console 22 applies the second drive signal 80 to the ultrasonic surgical tool 20. The presence of the harmonic signal 44 generated by applying the second drive signal 50 is reduced compared to the presence of the harmonic signal 44 generated by applying the first drive signal 40. The specific steps of this method 12 are described in detail below as follows. will be described in detail.

[0032] The console 22 executes step 202 to obtain the characteristics of the harmonic signal 44. The characteristics of the harmonic signal 44 can be characteristics based on the time domain or the frequency domain. For example, regarding the time domain, the characteristics of the harmonic signal 44 are the wavelength λ2, the phase "P2", and the amplitude "a" For example, regarding the time domain, the characteristics of the harmonic signal 44 are the wavelength λ2, the phase "P2", and the amplitude "a" It can include at least one of "2" (see FIG. 13). Regarding the frequency domain , as shown in FIGS. 6 and 7 described below, for example, the characteristics of the harmonic signal 44 can include at least one of the frequency, magnitude, and phase of the harmonic signal 44. For example , the frequency of the harmonic signal 44 is a component of the harmonic frequency 43, and more specifically, it is the second high harmonic frequency (e.g., 51 kHz). Those skilled in the art will recognize that any characteristic of the harmonic signal 44 can be obtained individually or in combination from the time domain and the frequency domain.

[0033] As described above, the characteristics of the first drive signal 40 may be determined in advance or may be known. Therefore, the characteristics of the first drive signal 40 and the characteristics of the harmonic signal 44 can be determined at different times. Alternatively, or in addition to this, when the characteristics of the first drive signal 40 are unknown, the console 22 can execute step 202 to further obtain the characteristics of the first drive signal 40. In other words, the characteristics of the first drive signal 40 and the characteristics of the harmonic signal 44 can be determined simultaneously or at different times .

[0034] In one embodiment, the console 22, among other things, obtains the characteristics of the harmonic signal 44 by generating samples of the current and voltage related to the application of the first drive signal 40 . More specifically, the voltage samples are based on the handpiece voltage V , and the current samples are based on the handpiece current i HP . The characteristics of the harmonic signal 44 are related to the waveform of the harmonic signal 44 . Therefore, the characteristics of the harmonic signal 44 are present in the current and voltage samples, and their samples HP . . Therefore, the characteristics of the harmonic signal 44 are present in the current and voltage samples, and their samples It can be extracted from the sample.

[0035] In one example, the console 22 obtains the characteristics of the harmonic signal 44 by measuring or starting from a known static capacitance value C o The magnitude and phase of both the voltage and current for the component of the fundamental frequency 41 of the first drive signal 40 are determined in advance or are known and can be accessed from the memory 28. With this information known, the console 22 drives the handpiece 21 and the tip 26 with a first drive signal 40 set to a relatively low vibration level at the component of the fundamental frequency 41 (e.g., 25.5 kHz). The console 22 uses a tracking algorithm to monitor resonance to continuously drive the handpiece 21 and the tip 26 at the component of the fundamental frequency 41. The tracking algorithm is executed by the controller 30 The controller 30 continuously measures and / or calculates those resonances as the handpiece 21 and the tip 26 vibrate. The tracking algorithm is designed to make appropriate adjustments to achieve the designed resonance when the measured resonance deviates from the desired resonance. The tracking algorithm can be continuously implemented during the operation of the surgical tool 20 It will be recognized by those skilled in the art that any suitable tracking algorithm can be implemented

[0036] The console 22 uses the sampling module 34 to obtain samples of the current and voltage generated by applying the first drive signal 40. The console 22, for example, obtains the handpiece current i as shown in FIG. 5 above HP ​​​​​and the handpiece voltage V HP By sampling the current and the handpiece voltage V, current and voltage samples are obtained. Alternatively, the console 22 can monitor and / or sample the impedance of the handpiece 21 and the tip portion 26 and derive current and voltage samples. The console 22 uses an analog-to-digital conversion device or the like to convert the current and voltage samples for further analysis. The console 22 does not need to generate a waveform as shown in FIG. 5 to sample or analyze the characteristics of the first drive signal 40 and / or the harmonic signal 44. Instead, samples can be generated and analyzed based on non-visual data such as binary values. The console 22 can obtain samples during or after the application of the first drive signal 40 to the surgical tool 20. The obtained samples can be stored in the memory 28 so that the controller 30 can access the samples at any appropriate time after sample acquisition. It should be understood by those skilled in the art that the console 22 analyzes the samples to obtain the characteristics of the harmonic signal 44. By obtaining the characteristics of the harmonic signal 44, the console 22 can measure distortion in both the handpiece current i and the handpiece voltage V at, for example, the second harmonic frequency 43. In one example, the console 22 uses FFT analysis techniques

[0037] to obtain the characteristics of the harmonic signal 44. Here, the console 22, more specifically, the FFT module 37 performs the FFT of the current and voltage samples. The console 22 can HP and the handpiece voltage V HP at both (e.g., at the second harmonic frequency 43). In one example, the console 22 uses FFT analysis techniques to obtain the characteristics of the harmonic signal 44. Here, the console 22, more specifically, the FFT module 37 performs the FFT of the current and voltage samples. The console 22 can During the application of the drive signal, current and voltage samples can be acquired and processed in real time. This is possible.

[0038] FIG. 10 shows an example of the FFT of the sampled handpiece current i. HP 25. The frequency components of 5 kHz and 51 kHz have larger amplitudes compared to other parts of the spectrum. It is shown that when the console 22 determines that the measured distortion is quite small based on the sample, the console 22 can continue to increase the machine current i until unacceptable harmonic vibrations occur. Here, the console 22 increases the machine current i until the amplitude of the component (second harmonic) of the harmonic frequency 43 is approximately the same as the amplitude of the component of the fundamental drive frequency 41, that is, 25.5 kHz. current i m current i m is increased.

[0039] The characteristics of the harmonic signal 44 can be further understood based on FIGS. 6 and 7 above. These figures show graphs representing the results of performing FFT in the examples described. For simplicity, the content of FIGS. 6 and 7 is not repeated. Those skilled in the art will understand that the FFT can provide data indicating the conversion, and therefore, it is not necessary to generate graphs as shown in FIGS. 6, 7, and 10 to obtain the characteristics of the harmonic signal 44. Thus, in a particular embodiment, the FFT of the current and voltage waveforms is performed to actively generate the second drive signal 80, and therefore, the FFT is not only used for diagnosis. not.

[0040] To determine the characteristics of the harmonic signal 44, the console 22 further uses the first drive signal 40. ​​​​​​​​The characteristics of the harmonic signal 44 can be compared to the characteristics of the harmonic signal 44. obtains the difference between the phase P1 of the first drive signal 40 and the phase P2 of the harmonic signal 44. The console 22 detects the handpiece voltage V at the fundamental frequency 41. HP and Handpiece current i at harmonic frequency 43 HP Calculate the phase difference between the Thus, the console 22 generates a handpiece voltage V at the first harmonic frequency. HP Against The handpiece current i at the second harmonic frequency HP Find the phase of the first harmonic frequency. Handpiece voltage at wave number V HP Handpiece at the second harmonic frequency current i HP The phase of is also known as the phase angle.

[0041] To do this, the console 22 supplies the handpiece voltage V HP and handpiece current i HP For at least one of the above, the harmonic frequency 43 component is separated from the fundamental frequency 41 component. As an example, FIG. 11 shows the handpiece current i HP Similar to Samp Ringed handpiece current i HP The sampled handpiece current i H P The waveform of has two frequency components, namely, a fundamental frequency 41 component and a harmonic frequency 43 Contains the ingredients.

[0042] Figure 12 shows the handpiece voltage V HP The waveform of the fundamental frequency 41 component extracted from In particular, in this example, the waveform of FIG. 12 is the source waveform of the first drive signal 40 of FIG. is the same as. That is, the waveform including the component of the separated fundamental frequency 41 is the first drive signal before the harmonic signal 44 generated by applying 40 is brought about, the first drive signal 40 is equivalent to the supply source waveform.

[0043] In FIG. 13, the component of the harmonic frequency 43 extracted from the handpiece current i in FIG. 11 HP is shown as a separated waveform. Therefore, FIG. 3 shows the separated harmonic signal 44 generated by applying the first drive signal 40. As shown, the harmonic signal 44 has a sine waveform including frequency components related to the wavelength λ2 of the harmonic signal 44. Also, the harmonic signal 44 also has a phase “P2” and an amplitude “a2”.

[0044] In one embodiment, the console 22 calculates the phase angle to determine the phase of the handpiece voltage V in the component of the fundamental frequency 4 1 and the phase difference from the phase of the handpiece current i at the harmonic frequency 43. In this example, using the specific frequencies, phases, and amplitudes of the handpiece voltage V HP and the handpiece current i HP , the console 22 calculates the phase angle from the following HP formula. handpiece current i HP . Using the specific frequencies, phases, and amplitudes of the handpiece voltage V and the handpiece current i, the console 22 calculates the phase angle from the following

Equation

[0045] Here, the console 22 determines that the phase of the harmonic frequency 44 (51.5 k HP Hz) of the handpiece current i is shifted by -90 degrees with respect to the handpiece voltage V at the component of the fundamental frequency 41 (25.5 kHz). It is determined that the phase is shifted by -90 degrees with respect to the handpiece voltage V at the component of the fundamental frequency 41 (25.5 kHz). It is determined that the phase is shifted by -90 degrees HP with respect to the handpiece voltage V at the component of the fundamental frequency 41 (25.5 kHz). It is determined that the phase is shifted by -90 degrees with respect to the handpiece voltage V at the component of the fundamental frequency 41 (25.5 kHz). It is determined that the phase is shifted by -90 degrees Then, the console 22 can adjust the cancel signal 70. Mainly, for mathematically canceling the amplitude of the harmonic signal 44, the phase of the cancel signal 70 is shifted by 180 degrees with respect to the phase of the harmonic signal 44. The cancel signal 70 is related to the first drive signal 4 0. The current of the cancel signal 70 is necessarily in phase with the voltage of the cancel signal 70 . The waveform of the identified harmonic current is shifted by 90 degrees from the first drive signal 40 . To cancel the harmonic signal 44 with the cancel signal 70, the cancel signal 7 0 is shifted by 90 (-90) degrees in the opposite direction with respect to the first drive signal 40. As a result , the phase of the cancel signal 70 is shifted by 180 degrees with respect to the phase of the harmonic signal 44 .

[0046] Method 12 includes, in step 206, generating a cancel signal 70 in the console 22 based on the characteristics of the harmonic signal 44. The cancel signal 70 is configured to reduce the presence of the harmonic signal 44, thereby minimizing the influence of the harmonic signal 44. In one embodiment, the cancel signal 70 is made to have the highest effect with respect to reducing the presence of the harmonic signal 44 . In practice, the cancel signal 70 is based on one or more characteristics of the unwanted machine current i . Thus, the cancel x signal 70 minimizes the presence of the harmonic signal 44 within the unwanted machine current i . In other words, in the examples described herein, the cancel signal 70 minimizes the unwanted machine current i x at the component of the second harmonic frequency 43, thereby minimizing the handpiece current i x , and thereby the handpiece current i HPMinimize the harmonic distortion. The console 22 uses the signal generator 36 to generate a cancellation signal 70. The data related to the generated cancellation signal 70 can be stored in the memory 28.

[0047] FIG. 14 shows an example of the waveform of the cancellation signal 70. As shown, the cancellation signal 70 has a sine waveform including frequency components related to the wavelength λ3 of the cancellation signal 70. Also, the cancellation signal 70 also has a phase “P3” and an amplitude “a3”.

[0048] In one embodiment, the console 22 generates a cancellation signal 70 based on the frequency of the harmonic signal 44. For example, the frequency of the cancellation signal 70 can be determined to minimize the harmonic signal 44. More specifically, the console 22 generates the cancellation signal 70 such that the frequency of the cancellation signal 70 is similar to the frequency of the harmonic signal 44. In that case, the wavelength λ3 of the cancellation signal 70 in FIG. 14 is the same as the wavelength λ2 of the harmonic signal 44 in FIG. 13. More specifically, in this example, the frequency of the cancellation signal 70 is set to 51 kHz, which is the frequency obtained for the harmonic signal 44. By having the same frequency as the harmonic signal 44, the cancellation signal 70 targets the components of the harmonic frequency 43 directly to reduce the influence of the components of the harmonic frequency 43 without affecting the components of the fundamental frequency 41 or bringing about other unwanted frequencies. Those skilled in the art will recognize that the frequency of the cancellation signal 70 may not be exactly equal to, but may be similar to, the components of the harmonic frequency 43. For example, the cancellation signal 70 ​​​​​​​​​​​​The frequency of the cancellation signal 70 may be several hundred hertz greater than or less than the harmonic frequency 4 3. In another example, the frequency of the cancellation signal 70 may be 1 kHz greater than or less than the harmonic frequency 43.

[0049] The cancellation signal 70 can further be made such that the phase P3 of the cancellation signal 70 is shifted with respect to the phase P 2 of the harmonic signal 44. In one embodiment, the phase P3 of the cancellation signal 70 is determined to minimize the harmonic signal 44. In one example , the phase P3 of the cancellation signal 70 is shifted 180 degrees with respect to the phase P2 of the harmonic signal 44 . Thus, the phase P3 of the cancellation signal 70 in FIG. 14 is shifted by a half cycle with respect to the phase P2 of the harmonic signal 4 4 in FIG. 13. By shifting the phase P3 by 180 degrees with respect to the phase P2 of the harmonic signal 44, the amplitude a3 of the cancellation signal 70 becomes the exact opposite of the amplitude a2 of the harmonic signal 44 as shown in FIG. 14, so that the cancellation effect of the harmonic signal 44 by the cancellation signal 70 is maximized. Those skilled in the art will recognize that the phase P3 of the cancellation signal 70 may be shifted by an angle other than 180 degrees with respect to the phase P2 of the harmonic signal 4 4. For example, the phase P3 of the cancellation signal 70 may be shifted by any positive or negative odd multiple of 180 degrees, such as 540 degrees, -180 degrees, etc. will recognize. For example, the phase P3 of the cancellation signal 70 may be shifted by any positive or negative odd multiple of 180 degrees, such as 540 degrees, -180 degrees, etc.

[0050] The cancellation signal 70 can be further designed such that the amplitude a3 of the cancellation signal 70 is adjusted with respect to the amplitude a2 of the harmonic signal 44. In one embodiment, as shown in FIG. 14 , the amplitude a3 of the cancellation signal 70 is equal to the amplitude a2 of the harmonic signal 44. The cancellation signal 70 By making the amplitude a3 of the harmonic signal 70 equal to the amplitude a2 of the harmonic signal 44, the cancellation signal The effect of canceling the harmonic signal 44 by the cancellation signal 70 is maximized. The amplitude a3 of 70 is equal to the amplitude a2 of the harmonic signal 44, and vice versa, as shown in FIG. (based on phase shift).

[0051] Alternatively, if necessary, the cancellation signal 70 may be further adjusted to have an amplitude a3 of the cancellation signal 70. is designed to be larger or smaller than the amplitude a2 of the harmonic signal 44. For example, in some cases, the amplitude a3 of the cancellation signal 70 may be greater than the amplitude a3 of the harmonic signal 44. It is twice the width a2. According to various other levels not specifically described in this specification In the case where the amplitude a3 of the cancellation signal 70 can be set in relation to the amplitude a2 of the harmonic signal 44, Those skilled in the art will recognize that in some cases, the position of the cancellation signal 70 may be Phase a3 can be designed to minimize harmonic signals 44.

[0052] In another embodiment, the amplitude a3 of the cancellation signal 70 is set to a value smaller than the cancellation effect on the harmonic signal 44. Based on an amplitude adjustment algorithm designed to monitor the effect of amplitude changes on the cell signal 70. For example, the amplitude adjustment algorithm starts with a relatively small amplitude a3. , the amplitude a3 can be increased until the component at harmonic frequency 43 is minimized. The source 22 uses a feedback loop to monitor the effect of the harmonic frequency 43 on the content It is possible.

[0053] The console 22 determines at least one or a combination of any of the characteristics of the harmonic signal 44. Those skilled in the art will recognize that a cancellation signal 70 can be generated based on the matching. For example, the cancellation signal 70 is based on the frequency and amplitude a2 of the harmonic signal 44, but may be generated without being based on the phase P2 of the harmonic signal 44. Alternatively, the cancellation signal 7 0 is based on the frequency and phase P2 of the harmonic signal 44, but may be generated without being based on the amplitude a2 of the harmonic signal 44. In such a situation where some characteristics of the harmonic signal 44 are not considered when designing the cancellation signal 70, the cancellation signal 70 can be generated based on, for example, an alternative or default frequency, phase, or amplitude. In step 208, the console 22 combines the first drive signal 40 and the cancellation signal 70 to generate a second drive signal 80. In other words, the console 22 generates the second drive signal 80 by combining the cancellation signal 70 with the original or source first drive signal 40 (resulting in no generation of the harmonic signal 44). The console 22 uses the signal

[0054] combiner 38 to add these two signals together. The console 22 can access the information about the first drive signal 40 and the cancellation signal 70 stored in the memory 28 . In step 208, the console 22 combines the first drive signal 40 and the cancellation signal 70 to generate a second drive signal 80. That is, the console 22 generates the second drive signal 80 by combining the cancellation signal 70 with the original or source first drive signal 40 (resulting in no generation of the harmonic signal 44). The console 22 uses the signal combiner 38 to add these two signals together. The console 22 can access the information about the first drive signal 40 and the cancellation signal 70 stored in the memory 28 . The console 22 can access the information about the first drive signal 40 and the cancellation signal 70 stored in the memory 28 .

[0055] FIG. 15 shows the output drive voltage of the second drive signal 80 for the example described herein. Similar to the first drive signal 40, the second drive signal 80 is a sine wave to assist in the proper ultrasonic operation of the surgical tool 20. Similar to the first drive signal 40, the second drive signal 80 is a sine wave to assist in the proper ultrasonic operation of the surgical tool 20. Similar to the first drive signal 40, the second drive signal 80 is a sine wave to assist in the proper ultrasonic operation of the surgical tool 20.

[0056] The cancellation signal 70 is effectively combined with the handpiece voltage V HP . In that case, the The output drive voltage of the drive signal 80 is the changed handpiece voltage V HP’ and can be understood, that is, there are cases where it changes in relation to the original handpiece voltage V of the first drive signal 40. The second drive signal 80 in FIG. 15 is based on the synthesis of the 25.5 kHz first drive signal 40 (FIG. 12) HP and the 51 kHz cancel signal 70 (FIG. 14). In that case, the voltage output of the second drive signal 80 includes both the 25.5 kHz drive signal and the 51 kHz cancel signal. In other words, the cancel signal 70 provides a second frequency component 77 to ensure the component of the fundamental frequency 41 of the main drive voltage V . This second frequency component 77 has a phase shift of 180 degrees compared to the component of the harmonic frequency 43, and is in the component of the second harmonic frequency 43 with a phase shift, thereby effectively minimizing the component of the harmonic frequency 43 . HP .

[0057] The console 22, more specifically the signal synthesizer 38, synthesizes the first drive signal 40 and the cancel signal 70 using mathematical operations. In the case of the example described in this specification, the signal synthesizer 38 synthesizes the signals using the following equation [2].

Equation

[0058] More specifically, when the frequencies, phases and amplitudes of the first drive signal 40 and the cancel signal 70 are input, equation [2] is expressed as follows.

Equation

[0059] ​​​​In step 210, the console 22 transmits the second drive signal 80 to the ultrasonic surgical tool 2. Similar to the first drive signal 40, the console 22 applies the ultrasonic surgical tool 2 0, and more specifically, applies a second drive signal 40 to the transducer 24. That is, the amplifier 32 amplifies the voltage of the second drive signal 80, and the transducer 24 outputs the second drive signal 80. The electrical energy of the signal 80 is converted into mechanical energy.

[0060] By introducing the cancellation signal 70, the second drive signal 80 cancels out the harmonic signal 44. The second drive signal 80 is specifically designed to counteract undesirable vibratory motion. The transducer 24 is driven to produce a force that opposes the force. This opposing force is undesirable. In fact, the vibration caused by applying the second drive signal 80 is effectively cancelled. The presence of the harmonic signal 44 is caused by applying the first drive signal 40. More specifically, the desirably No machine current i x In other words, the presence of harmonic signals 44 in the In the example described above, the unwanted mechanical current at the second harmonic frequency 43 is Flow x is minimized after applying the second drive signal 80, thereby reducing the handpiece current i HP Harmonic distortion in the signal is minimized.

[0061] In some embodiments, the console 22 may be configured to cancel during operation of the surgical tool 20. For example, the console 22 may be configured to generate "n" repetitive loop signals 70. (first, second, third drive signal, etc.) and apply each "nth" drive signal. The characteristics of the harmonic signal (if present) generated thereby can be obtained. The console 22 tracks the harmonic distortion during the entire use of the tip 26 or during a surgical procedure and can provide "n" cancellation signals. In such a case, each "nth" drive signal, each "nth" cancellation signal, and each resulting harmonic signal are in different scenarios There are cases. In some embodiments, the console 22 continues this process until it determines that the harmonic signal 44 is at an appropriate level. For example, the console 22 continues this process until it determines that the harmonic signal 44 is below a predetermined threshold (e.g., the magnitude of the component of the harmonic frequency 43 is less than 5% of the magnitude of the component of the fundamental frequency 41), or until the harmonic signal 44 is removed. The console 22 can continue this process until it determines that the harmonic signal 44 is below a predetermined threshold (e.g., the magnitude of the component of the harmonic frequency 43 is less than 5% of the magnitude of the component of the fundamental frequency 41), or until the harmonic signal 44 is removed. The console 22 can continue this process until it determines that the harmonic signal 44 is below a predetermined threshold (e.g., the magnitude of the component of the harmonic frequency 43 is less than 5% of the magnitude of the component of the fundamental frequency 41), or until the harmonic signal 44 is removed. The console 22 can continue this process until the harmonic signal 44 is removed.

[0062] The console 22 can measure and track the level of the harmonic signal 44 using any suitable method to generate the cancellation signal 70 or each "nth" cancellation signal . In one example, the console 22 calculates the component of the harmonic frequency 43 in the handpiece current i using a known value for Co. When minimized to near zero, the component of the harmonic frequency 43 of the current i flowing through Co represents the remaining unwanted motional HP current i flowing through Co represents the remaining unwanted motional C0 current i flowing through Co represents the remaining unwanted motional current i x flowing through Co represents the remaining unwanted motional current i

[0063] FIG. 15 shows the waveforms of the modified handpiece current i HP’ and handpiece voltage V HP’ after applying the harmonic cancellation method 12. Compared with the waveforms in FIG. 5, the waveforms in FIG. 15 The influence of the harmonic signal 44 thereon is greatly minimized. After the second drive signal 80 is applied Since the component of the fundamental drive frequency 41 is not significantly affected by the component of the harmonic frequency 43 the waveform of the handpiece current i HP’ exhibits a minimum phase shift φ with respect to the handpiece voltage V HP’ . Furthermore, since the handpiece current i and the handpiece voltage V HP’ HP’ HP’ show mainly one frequency component, i.e., only the fundamental drive frequency 41 component, the waveform is substantially sinusoidal.

[0064] Figs. 16 and 17 show the respective fast Fourier analyses for each of the waveforms of the modified handpiece voltage V HP’ and the handpiece current i HP’ HP’ . Compared with Figs. 6 and 7, the FFT analysis reveals that the component of the fundamental drive frequency 41 (i.e., 25.5 kHz) is substantially not affected by the component of the harmonic frequency 43 of the harmonic signal 4 4 (e.g., 51 kHz). Furthermore, the magnitude of the component of the harmonic frequency 43 at 51 kHz is reduced . In the case of the handpiece voltage V HP’ HP’ , the magnitude of the component of the harmonic frequency 43 is 25% of the magnitude of the component of the harmonic frequency 43 resulting from the first drive signal 40. In the case of the handpiece current i HP’ HP’ , the magnitude of the component of the harmonic frequency 43 is substantially removed.

[0065] Furthermore, since the mechanical current i m is related to the mechanical displacement of the tip 26, minimizing the distortion in the handpiece current i HP HP HP also minimizes the distortion in the handpiece voltage V can be prioritized over. Thus, the handpiece current i HP has more handpiece voltage V HP has greater strain inside, but both waveforms show significant improvement at a frequency of 51 kHz as shown.

[0066] Furthermore, by using method 12 to suppress the component of the harmonic frequency 43, there may be an opportunity to perform non-linear control and two-mode control of the tip 26 . In the examples given herein , the non-linear behavior is such that when the surgical tool 20 is driven by a component of the basic drive frequency 41, a voltage sine wave of 25.5 kHz, the combination of the handpiece 21 and the tip 26 behaves in such a way as to vibrate at a component of the harmonic frequency 43, 51 kHz . By suppressing the component of the harmonic frequency 43, the tip 26 can be dynamically controlled to make it easier for the surgeon to approach areas within the body that were previously difficult to reach. In other words , by reducing the adverse effects of the components of the harmonic signal 41, the system 10 and method 12 enhance the versatility of using various types and shapes of ultrasonic tools and tips that often exhibit harmonic distortion . The system 10 and method 12 further enable the simultaneous control (e.g., two-mode control) of two different resonance modes of the tip 26 in order to enhance the cutting performance . Furthermore, the cancellation signal 70 reduces the harmonic signal 44, but the cancellation signal 70 can also be configured to introduce additional frequency components into the second drive signal 80 in order to achieve two-mode control of the tool 20 . . .

[0067] Figure 19 shows a number of important parameters for controlling the combination of the handpiece 21 and the tip 26 ​​​A table is provided showing significant improvements in the parameters measured during application of the second drive signal 80. Handpiece voltage V HP’ and handpiece current i HP’ is the application of the first drive signal 40 The handpiece voltage V measured during HP and handpiece current i HP Compared to 22% Similarly, the handpiece pressure measured during application of the second drive signal 80 is reduced by 23%. The impedance of the handle 21 and the tip 26 is measured during application of the first drive signal 40. The impedance of the end piece 21 and tip 26 is reduced by 23%. As a result, the hand-pickup frequency at 51 kHz component measured during application of the second drive signal 80 was Source current i HP’ The relative magnitude of the first drive signal 40 is substantially eliminated. In addition, in this example, the second drive signal is reduced by 98.8% compared to when the second drive signal is applied. Unwanted machine current i present at 51 kHz after application of No. 80 x was 3.4mA This is in accordance with the desired current present at 51 kHz after application of the first drive signal 40, which was 83 mA. Non-linear mechanical current i x This significantly reduces unwanted vibrations. show.

[0068] These results demonstrate that system 10 and method 12 effectively reduce the presence of harmonic signals 44. , thereby clearly demonstrating the reduction of harmonic distortion resulting from vibrations of the surgical tool 20. As a result, the system 10 and method 12 are able to measure the impedance of the surgical tool 20. the power and voltage required to maintain the characteristic vibration displacement of the tip 26; The heating of section 26, the energy returned to console 22, and the components of harmonic frequency 43 are clearly reduced. Thereby, furthermore, system 10 and method 12 greatly improve the tissue resection performance of surgical tool 20.

[0069] Several embodiments have been discussed in the above description. However, the embodiments discussed herein are not intended to be exhaustive or to limit the invention to any particular form. The terms used are of a descriptive nature and not of a limiting nature. Many changes and modifications are possible in light of the above teachings, and the invention can be practiced in ways other than those specifically described.

[0070] Numerous features and advantages of the invention are apparent from the detailed description, and accordingly, the appended claims are intended to cover all such features and advantages that fall within the true spirit and scope of the invention. Further, many modifications and variations will occur to those skilled in the art, so it is not desirable to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents that fall within the scope of the invention may be employed. ​​​​​​​​​​​

Claims

1. A console for controlling ultrasonic surgical tools and reducing the presence of harmonic signals, The aforementioned console includes a controller, The aforementioned controller, The ultrasonic surgical tool is driven by a first drive signal that includes a fundamental frequency component corresponding to the first resonance mode of the tip of the ultrasonic surgical tool. The frequency characteristics of the harmonic signals in the ultrasonic surgical tool, which are generated by driving the ultrasonic surgical tool with the first drive signal, are obtained. A cancellation signal is generated that includes harmonic frequency components corresponding to the frequency characteristics of the acquired harmonic signal and additional frequency components corresponding to the second resonance mode of the tip of the ultrasonic surgical tool. The cancellation signal is combined with the first drive signal to generate a second drive signal. The ultrasonic surgical tool is driven by the second drive signal, and the presence of harmonic signals in the frequency characteristics generated and acquired by driving the ultrasonic surgical tool by the second drive signal is reduced compared to the presence of harmonic signals in the frequency characteristics generated and acquired by driving the ultrasonic surgical tool by the first drive signal, and the tip of the ultrasonic surgical tool vibrates simultaneously in the first and second resonance modes. console.

2. The console according to claim 1, wherein the tip of the ultrasonic surgical tool vibrates in a nonlinear movement path when driven by the second drive signal.

3. The console according to claim 1 or 2, wherein the controller acquires the amplitude characteristics of the harmonic signal generated by driving the ultrasonic surgical tool with the first drive signal, and generates the cancellation signal based on the acquired frequency characteristics, the acquired amplitude characteristics and a predetermined default phase characteristic.

4. The console according to any one of claims 1 to 3, wherein the controller obtains the frequency characteristics of the harmonic signal by generating samples of current and voltage related to the first drive signal, and the frequency characteristics of the harmonic signal are present in the generated samples of current and voltage.

5. The console according to claim 4, wherein the controller obtains the frequency characteristics of the harmonic signal and determines the frequency characteristics of the harmonic signal by analyzing the fast Fourier transform of the generated current and voltage samples.

6. A method for controlling an ultrasonic surgical tool to reduce the presence of harmonic signals, performed by a console equipped with a controller, The controller drives the ultrasonic surgical tool with a first drive signal that includes a fundamental frequency component corresponding to a first resonance mode of the tip of the ultrasonic surgical tool. The controller acquires the frequency characteristics of the harmonic signals in the ultrasonic surgical tool, which are generated when the ultrasonic surgical tool is driven by the first drive signal. The controller generates a cancellation signal that includes frequency components based on the frequency characteristics of the acquired harmonic signal and additional frequency components corresponding to the second resonant mode of the tip. The controller performs the step of generating a second drive signal by combining the cancellation signal with the first drive signal, The steps include: the controller drives the ultrasonic surgical tool with the second drive signal, wherein the presence of harmonic signals in the frequency characteristics generated and acquired by driving the ultrasonic surgical tool with the second drive signal is reduced compared to the presence of harmonic signals in the frequency characteristics generated and acquired by driving the ultrasonic surgical tool with the first drive signal, and the tip of the ultrasonic surgical tool vibrates simultaneously in the first and second resonance modes; A method that includes this.

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