Composite waveform driving device and method for ultrasonic transducer in root canal irrigator

Abstract

The application belongs to the technical field of ultrasonic transducer driving of oral medical equipment, and specifically discloses a composite waveform driving device and method for an ultrasonic transducer in a root canal washing device. The device comprises, in sequence, a control module, a signal generation module, a waveform composite module, a power amplification module, an impedance matching module, an interface module, and a feedback monitoring module electrically connected with the control module and the interface module; the control module integrates an improved PID algorithm, the signal generation module generates a programmable basic waveform, the waveform composite module generates a composite waveform by proportional superposition, and the feedback monitoring module realizes real-time detection of multiple parameters. The method realizes transducer driving through parameter initialization, basic waveform generation, composite waveform synthesis, power amplification and impedance matching, combined with frequency tracking by the phase-locked + maximum current method, closed-loop feedback regulation of improved PID power regulation and temperature protection. The application takes into account the cleaning effect and safety, improves the driving stability, reduces the energy consumption, prolongs the service life of the transducer, and is suitable for various root canal washing scenes.

Description

Technical Field

[0001] This invention belongs to the field of ultrasonic transducer driving technology in dental medical equipment, and particularly relates to a composite waveform driving device and method for ultrasonic transducers in root canal irrigation devices. Background Technology

[0002] Root canal treatment is currently the core treatment method for pulpitis and periapical periodontitis. The root canal sizing device is a key piece of equipment, and its core component is the ultrasonic transducer. By driving the ultrasonic transducer to generate mechanical vibration, the sizing fluid is stimulated to form an acoustic flow effect and cavitation effect, thereby removing the smear layer, bacterial biofilm and necrotic tissue from the root canal wall. Its cleaning effect directly determines the success rate of treatment.

[0003] Currently, the driving methods of ultrasonic transducers in root canal slurries are mainly divided into sinusoidal wave drive and square wave drive. The advantages of a single sinusoidal wave drive are smooth waveform, low harmonic content, high electroacoustic conversion efficiency (up to 85% or more), and low transducer heat generation, which can effectively extend the equipment's lifespan and improve patient comfort. However, its disadvantages include excessively uniform energy output, mild cavitation effect, and limited effectiveness in removing stubborn biofilms in narrow and curved sections of the root canal, affecting the quality of root canal treatment. While a single square wave drive can generate strong impact force through waveform abrupt changes and enhance the cavitation effect, the high content of higher harmonics leads to significant transducer thermal effects. Long-term use can easily cause transducer overheating and damage, and the vibration is uneven and noisy, causing strong patient discomfort. Furthermore, the electroacoustic conversion efficiency is only 60%-70%, resulting in significant energy waste. In addition, existing drive controls mostly use traditional PID algorithms, which do not meet the requirements for phase-locking accuracy and timing, making it difficult to accurately control the transducer output power and adapt to the slurry needs of different root canal shapes and different types of debris.

[0004] Therefore, developing a composite waveform driving device and method that can balance cleaning effect, safety and stability, and is suitable for root canal irrigation scenarios has become an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite waveform driving device and method for an ultrasonic transducer of a root canal scalpel. By constructing a composite driving waveform of "sine wave carrier + square wave pulse superposition", the invention achieves the synergy of "basic cleaning stability" and "local cleaning enhancement", thereby reducing transducer heat loss, improving treatment comfort, and enhancing the removal effect on stubborn contaminants in the root canal.

[0006] To solve the above technical problems, the present invention provides a composite waveform driving device for an ultrasonic transducer in a root canal irrigator. The device includes a control module, a signal generation module, a waveform composite module, a power amplification module, an impedance matching module, and an interface module that are connected in sequence. It also includes a feedback monitoring module that is electrically connected to both the control module and the interface module.

[0007] The control module is used to receive the detection signal from the feedback monitoring module and output control commands to the signal generation module, waveform composite module and power amplification module to achieve precise adjustment of drive parameters and frequency tracking control.

[0008] The signal generation module is used to generate various basic waveforms with programmable control over frequency, phase, and amplitude;

[0009] The waveform composite module is used to receive two or more basic waveforms output by the signal generation module, and to superimpose and composite the basic waveforms according to the composite ratio set by the control module to generate the target composite waveform (such as sine wave + square wave, sine wave + triangle wave).

[0010] The power amplification module is used to amplify the power of the target composite waveform, and the amplified signal power meets the driving requirements of the ultrasonic transducer.

[0011] The impedance matching module is used to match the dynamic impedance of the ultrasonic transducer with the output impedance of the power amplifier module, reduce energy reflection loss, and ensure efficient energy transmission.

[0012] The interface module is used to connect to the ultrasonic transducer assembly to realize the transmission of composite waveform drive signals and feedback of the working status of the ultrasonic transducer assembly.

[0013] The feedback monitoring module is used to detect the working status of the ultrasonic transducer assembly in real time and transmit the detection signal to the control module.

[0014] Furthermore, in this invention, the control module integrates a dual frequency tracking mechanism of phase-locked loop (PLL) automatic frequency tracking and maximum current method, combined with an improved PID control algorithm. The core structure of the improved PID control algorithm is "adaptive parameter PID + PLL cooperative control + anti-interference compensation," and the control logic is as follows:

[0015]

[0016] The specific meanings of each parameter in this invention are as follows:

[0017] The control output, in this invention, is the drive frequency correction amount or power adjustment amount, used to adjust the frequency control of the signal generation module or the gain of the power amplification module in real time, so that the ultrasonic transducer can quickly return to the resonant working state.

[0018] The time-varying proportional gain is the gain of the proportional element that dynamically adjusts according to the system's operating state, used to adjust the current deviation signal. To enable rapid response; when the deviation is large, increase To improve frequency tracking speed; when the deviation is small, reduce To suppress system oscillations and ensure control stability;

[0019] Deviation signal, which is the difference between the target working state and the actual working state, is divided into two categories in this invention:

[0020] First: Frequency tracking loop deviation. ,in The phase difference of the resonant target (taken as 0°). This represents the real-time phase difference between the driving voltage and the operating current of the ultrasonic transducer.

[0021] Second: Power regulation loop deviation: ,in To set the output power, This refers to the real-time output power of the ultrasonic transducer.

[0022] The time-varying integral time constant is a dynamically adjusted time parameter of the integral element, and its reciprocal... For integral gain: when the deviation is large, decrease To enhance the integral action and quickly eliminate accumulated errors; when the deviation is small, increase To reduce the integral effect and avoid system overshoot caused by integral saturation;

[0023] The deviation integral term is the cumulative summation of historical deviation signals, used to eliminate steady-state errors in the system and ensure that the ultrasonic transducer eventually converges to the resonant state without error.

[0024] The time-varying differential time constant is a dynamically adjusted time parameter of the differential element, used to measure the rate of change of the deviation. To respond, predict system behavior in advance, and suppress overshoot and oscillation: when the deviation is small, increase To improve phase-locked loop accuracy and ensure vibration stability;

[0025] : Deviation change rate, which is the rate at which the deviation signal changes over time. The differential element uses this parameter to sense the system trend in advance and avoid control instability caused by sudden deviation changes.

[0026] The disturbance deviation compensation amount is a feedforward compensation amount introduced by external disturbances such as frequency drift, temperature change, and load fluctuation. It is directly superimposed on the PID control output, without relying on the slow correction of the integral link, which significantly improves the system's anti-interference capability and response speed. Furthermore, the basic waveforms generated by the signal generation module include sine waves and square waves. The sine wave frequency range is 30 kHz to 50 kHz (adapted to commonly used frequencies for root canal irrigation), and the square wave frequency range is 1 kHz to 5 kHz. The amplitude adjustment accuracy reaches 12 bits, and the parameters of the output waveform are adjusted in real time through commands received from the control module via the SPI interface.

[0027] Furthermore, in this invention, the waveform composite module uses an integrated operational amplifier to form an inverting addition operation circuit. The composite ratio of various basic waveforms is adjusted in real time by the control module, with an adjustment range of 3:7 to 7:3, to meet the needs of different washing scenarios. The sine wave is used to provide stable vibration, and the square wave is used to provide pulse impact force to improve the cleaning effect.

[0028] Furthermore, in this invention, the power amplification module is a linear amplifier with overcurrent and overvoltage protection. It adopts a composite transistor circuit structure (a transistor with low power and high β value drives a transistor with high power and low β value) to amplify the composite waveform signal output by the waveform composite module. The amplified signal power ranges from 0.5 W to 3.2 W, which meets the driving requirements of the ultrasonic transducer. At the same time, the overcurrent and overvoltage protection function can prevent the transducer and driving device from being damaged due to overload.

[0029] Furthermore, in this invention, the impedance matching module consists of an LC resonant network and a π-type matching circuit.

[0030] Furthermore, in this invention, the feedback monitoring module includes a voltage sampling unit, a current sampling unit, a temperature sampling unit, a vibration sampling unit, and a signal conditioning unit; after each sampling unit collects the corresponding signal, it is processed by the signal conditioning unit and outputs the phase difference, real-time power, operating temperature, and vibration amplitude signals to the control module for frequency tracking, power adjustment, and safety protection control.

[0031] Furthermore, in this invention, one end of the interface module is electrically connected to the output end of the power amplifier module, and the other end is detachably connected to the ultrasonic transducer of the root canal irrigator, and has signal isolation function.

[0032] The present invention also provides a composite waveform driving method for an ultrasonic transducer in a root canal irrigator, applied to the aforementioned composite waveform driving device for an ultrasonic transducer in a root canal irrigator, specifically including the following steps:

[0033] Step S1: Parameter initialization: Set the driving parameters through the human-machine interface of the control module or the host computer. The driving parameters include the basic waveform type, basic waveform parameters, composite ratio, output power, frequency tracking accuracy and temperature threshold.

[0034] Step S2: Basic waveform generation. The control module outputs control commands to the signal generation module. The signal generation module generates two or more basic waveforms according to the set parameters. The control module then performs real-time calibration on the frequency and amplitude of the basic waveforms to ensure waveform stability.

[0035] Step S3: Composite Waveform Synthesis: The waveform composite module receives the basic waveform output by the signal generation module, and according to the composite ratio set by the control module, it superimposes and composites the basic waveform through the inverting addition circuit to generate the target composite waveform. The control module monitors and adjusts the parameters of the composite waveform in real time.

[0036] Step S4: Power Amplification and Impedance Matching: The power amplification module amplifies the target composite waveform signal. After the amplified composite waveform signal is matched by the impedance matching module, it is transmitted to the ultrasonic transducer through the interface module to drive the ultrasonic transducer to vibrate and realize the root canal cleaning operation.

[0037] Step S5: Real-time feedback and adjustment: The feedback monitoring module collects the vibration signal, temperature signal, current signal and voltage signal of the ultrasonic transducer in real time and transmits them to the control module. The control module performs frequency tracking, power adjustment and temperature protection processing on the signals.

[0038] Step S6: End of irrigation: After the root canal irrigation operation is completed, a stop command is issued through the control module. The signal generation module stops generating the basic waveform, the power amplification module stops outputting, the feedback module stops detecting, and the entire drive device is in standby mode.

[0039] Furthermore, in step S5 of this invention, the control module performs the following processing:

[0040] Frequency tracking: Calculate the phase difference between the voltage signal and the current signal, and use a combination of phase-locked automatic frequency tracking (zero-phase tracking or fixed-phase tracking) and the maximum current method to track the transducer's natural frequency drift in real time, and adjust the output frequency of the signal generation module to ensure that the transducer is always in a resonant state.

[0041] Power regulation: Based on the feedback current and voltage signals and the improved PID algorithm, the output power of the power amplifier module is dynamically adjusted to control the output power of the transducer to the set value. At the same time, the amplitude and composite ratio of the composite waveform are adjusted according to the vibration signal to optimize the washing effect.

[0042] Temperature protection: When the transducer temperature exceeds the set threshold, the control module automatically reduces the output power or stops driving. Normal driving will resume after the temperature drops to a safe range.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) Significantly improved cleaning effect: The composite waveform (such as sine wave + square wave) is used for driving, which combines the stable vibration of the sine wave and the pulse impact force of the square wave. It is also compatible with the commonly used frequency of 30 kHz to 50 kHz for root canal irrigation, which can effectively remove stubborn dirt, dentin debris and smear layer in the root canal. It is especially suitable for curved and small root canals. The cleaning efficiency is significantly improved compared with single waveform driving, and the mechanical damage to the root canal wall caused by single square wave driving is avoided, thus improving the quality of root canal treatment.

[0045] (2) High drive stability: It integrates a dual frequency tracking mechanism of phase-locked automatic frequency tracking and maximum current method, combined with an improved PID control algorithm, which can track the inherent frequency drift of the transducer in real time, improve the phase-locking accuracy, shorten the phase-locking time, ensure that the transducer is always in the best working state, and avoid drive instability caused by frequency drift.

[0046] (3) High safety and reliability: The feedback module monitors the temperature, vibration, current and voltage status of the transducer in real time, and has overcurrent and overvoltage protection and temperature protection functions, which can effectively prevent the transducer from overheating and overload damage and extend the service life of the transducer; at the same time, the interface module adopts a waterproof and corrosion-resistant design, which is suitable for the humid environment of dental clinics and improves the reliability of the device.

[0047] (4) Lower energy consumption: Through precise power adjustment and frequency tracking, ineffective energy consumption is avoided. Compared with the existing single waveform drive device, the energy consumption is reduced, which meets the energy-saving requirements and is more conducive to improving the endurance of the root canal scalpel device (battery powered). Attached Figure Description

[0048] The specific embodiments of the present invention will be further explained below with reference to the accompanying drawings.

[0049] Figure 1 This is a schematic diagram of the module connection of the composite waveform driving device of the ultrasonic transducer in the root canal irrigator of the present invention.

[0050] Figure 2 This is a schematic diagram of the workflow of the feedback monitoring module in the composite waveform driving device of the ultrasonic transducer in the root canal irrigator of the present invention.

[0051] Figure 3 This is a flowchart of the composite waveform driving method for the ultrasonic transducer in the root canal irrigator of the present invention. Detailed Implementation

[0052] Example 1

[0053] Combination Figure 1 and Figure 2 As shown, the composite waveform driving device of the ultrasonic transducer in the root canal irrigator of this embodiment includes a control module, a signal generation module, a waveform composite module, a power amplification module, an impedance matching module, and an interface module that are connected in sequence. It also includes a feedback monitoring module that is electrically connected to both the control module and the interface module.

[0054] In this embodiment, the control module is the core control unit of the entire device. It uses a 32-bit ARM Cortex-M4 core microcontroller as the main control chip and integrates an improved PID control algorithm. The control module is used to receive the detection signal from the feedback monitoring module and output control commands to the signal generation module, waveform composite module and power amplification module to achieve precise adjustment of drive parameters and frequency tracking control.

[0055] In this embodiment, preferably, the control module integrates a dual frequency tracking mechanism of phase-locked loop (PLL) automatic frequency tracking and maximum current method, combined with an improved PID control algorithm. The core structure of the improved PID control algorithm is "adaptive parameter PID + PLL collaborative control + anti-interference compensation". The control logic adds a dynamic parameter tuning module, a frequency deviation compensation module, and an anti-interference filtering module to the traditional PID. The core of the control is "deviation correction + scenario adaptation". Combining the working characteristics of the ultrasonic transducer (natural frequency drift, vibration amplitude change, temperature rise), the parameters of the three links are dynamically optimized, and the PLL tracking mechanism is coordinated to achieve precise control. The specific control logic is as follows:

[0056]

[0057] The specific meanings of each parameter in this embodiment are as follows:

[0058] The control output, in this embodiment, is the drive frequency correction amount or power adjustment amount, used to adjust the frequency control of the signal generation module or the gain of the power amplification module in real time, so that the ultrasonic transducer can quickly return to the resonant working state.

[0059] The time-varying proportional gain is the gain of the proportional element that dynamically adjusts according to the system's operating state, used to adjust the current deviation signal. To enable rapid response; when the deviation is large, increase To improve frequency tracking speed; when the deviation is small, reduce To suppress system oscillations and ensure control stability;

[0060] Deviation signal, which is the difference between the target working state and the actual working state, is divided into two categories in this embodiment:

[0061] First: Frequency tracking loop deviation. ,in The phase difference of the resonant target (taken as 0°). This represents the real-time phase difference between the driving voltage and the operating current of the ultrasonic transducer.

[0062] Second: Power regulation loop deviation: ,in To set the output power, This refers to the real-time output power of the ultrasonic transducer.

[0063] The time-varying integral time constant is a dynamically adjusted time parameter of the integral element, and its reciprocal... For integral gain: when the deviation is large, decrease To enhance the integral action and quickly eliminate accumulated errors; when the deviation is small, increase To reduce the integral effect and avoid system overshoot caused by integral saturation;

[0064] The deviation integral term is the cumulative summation of historical deviation signals, used to eliminate steady-state errors in the system and ensure that the ultrasonic transducer eventually converges to the resonant state without error.

[0065] The time-varying differential time constant is a dynamically adjusted time parameter of the differential element, used to measure the rate of change of the deviation. To respond, predict system behavior in advance, and suppress overshoot and oscillation: when the deviation is small, increase To improve phase-locked loop accuracy and ensure vibration stability;

[0066] : Deviation change rate, which is the rate at which the deviation signal changes over time. The differential element uses this parameter to sense the system trend in advance and avoid control instability caused by sudden deviation changes.

[0067] The disturbance deviation compensation amount is a feedforward compensation amount introduced by external disturbances such as frequency drift, temperature change, and load fluctuation. It is directly superimposed on the PID control output, without relying on the slow correction of the integral element, which significantly improves the system's anti-interference capability and response speed. Specifically, in this embodiment, the control module also integrates a human-machine interface, which includes an input unit and a display unit. The input unit is used to select functions and set parameters (such as waveform type, frequency, amplitude, composite ratio, etc.), and the display unit is used to display information such as current drive parameters and transducer operating status. It also supports communication with the host computer (via RS232 serial port) to realize remote control and parameter adjustment of the drive device by the host computer.

[0068] In this embodiment, the signal generation module uses a DDS chip as its core device, and an external 60 MHz active crystal oscillator provides a high-precision, low-jitter external clock for generating various basic waveforms with programmable frequency, phase, and amplitude. The DDS chip is either AD9852 or AD9845, with AD9852 being preferred.

[0069] In this embodiment, preferably, the basic waveforms generated by the signal generation module include sine waves and square waves. The frequency range of the sine wave is 30 kHz to 50 kHz (adapted to the commonly used frequency of root canal irrigation), and the frequency range of the square wave is 1 kHz to 5 kHz. The amplitude adjustment accuracy reaches 12 bits. The parameters of the output waveform are adjusted in real time by receiving instructions from the control module through the SPI interface.

[0070] In this embodiment, the waveform composite module is used to receive two or more basic waveforms output by the signal generation module, and to superimpose and composite the basic waveforms according to the composite ratio set by the control module to generate a target composite waveform (such as sine wave + square wave, sine wave + triangle wave).

[0071] In this embodiment, preferably, the waveform composite module uses an integrated operational amplifier (preferably LM324) to form an inverting adder circuit. The composite ratio of various basic waveforms is adjusted in real time by the control module, with an adjustment range of 3:7 to 7:3, to meet the needs of different washing scenarios. The sine wave is used to provide stable vibration, and the square wave is used to provide pulse impact force to improve the cleaning effect.

[0072] In this embodiment, the power amplification module is used to amplify the power of the target composite waveform, and the amplified signal power meets the driving requirements of the ultrasonic transducer.

[0073] In this embodiment, preferably, the power amplification module is a linear amplifier with overcurrent and overvoltage protection. It adopts a composite transistor circuit structure (a transistor with low power and high β value drives a transistor with high power and low β value) to amplify the composite waveform signal output by the waveform composite module. The amplified signal power range is 0.5 W to 3.2 W, which meets the driving requirements of the ultrasonic transducer. At the same time, the overcurrent and overvoltage protection function can prevent the transducer and driving device from being damaged due to overload.

[0074] In this embodiment, specifically, the impedance matching module is used to match the dynamic impedance of the ultrasonic transducer with the output impedance of the power amplification module, thereby reducing energy reflection loss and ensuring efficient energy transmission.

[0075] In this embodiment, preferably, the impedance matching module consists of an LC resonant network and a π-type matching circuit.

[0076] Specifically, in this embodiment, the interface module is used to connect the ultrasonic transducer assembly to realize the transmission of composite waveform drive signals and feedback of the working status of the ultrasonic transducer assembly. The ultrasonic transducer assembly includes an ultrasonic transducer, an amplitude transformer, and a washing needle. The ultrasonic transducer is the core device that converts electrical energy into high-frequency mechanical ultrasonic vibration, and is also commonly referred to as an ultrasonic transducer or piezoelectric transducer. The amplitude transformer, also called an ultrasonic amplitude transformer, amplitude amplification rod, or amplification rod, is a mechanical structural component connecting the ultrasonic transducer and the working head (washing needle).

[0077] In this embodiment, preferably, the interface module uses a waterproof and corrosion-resistant aviation plug. One end is electrically connected to the output end of the power amplifier module, and the other end is detachably connected to the ultrasonic transducer of the root canal irrigator, which facilitates the replacement and maintenance of the transducer and has a signal isolation function, effectively avoiding external interference from affecting the stability of the drive signal.

[0078] In this embodiment, the feedback monitoring module is specifically used to detect the working status of the ultrasonic transducer assembly in real time and transmit the detection signal to the control module.

[0079] In this embodiment, preferably, the feedback monitoring module includes a voltage sampling unit, a current sampling unit, a temperature sampling unit, a vibration sampling unit, and a signal conditioning unit; after each sampling unit collects the corresponding signal, it is processed by the signal conditioning unit and outputs the phase difference, real-time power, operating temperature, and vibration amplitude signals to the control module for frequency tracking, power adjustment, and safety protection control.

[0080] In this embodiment, the feedback monitoring module specifically acquires relevant signals through a vibration sensor, a temperature sensor, a current sampling circuit, and a voltage sampling circuit. The vibration sensor (preferably ADXL345 in this embodiment) is used to detect the vibration amplitude and frequency of the transducer; the temperature sensor (preferably DS18B20 in this embodiment) is used to detect the operating temperature of the transducer; the current sampling circuit acquires the current signal across the transducer through a sampling resistor, and the voltage sampling circuit acquires the driving voltage signal. Both are processed by the true RMS detection circuit and then transmitted to the control module to calculate the phase difference between the voltage and the current, thereby achieving frequency tracking and power regulation.

[0081] The improved PID control algorithm in this embodiment combines a phase-locked loop automatic frequency tracking mechanism with a maximum current method dual frequency tracking mechanism. It is optimized for the characteristics of ultrasonic transducer composite waveform driving scenarios. Its control principle is as follows:

[0082] (1) Time-varying parameter adaptive adjustment mechanism

[0083] Unlike traditional PID fixed parameter control, the proportional coefficient of this algorithm... Integral time constant Differential time constant It can be dynamically adjusted in real time based on the magnitude of the deviation, transducer temperature, and vibration status. When the system is in a state of large deviation (such as phase difference > 8°, power deviation > 10%), the voltage should be increased. With integral action (reducing) This method, combined with the maximum current method for rapid frequency sweeping, quickly locates the resonant frequency range of the ultrasonic transducer, shortening the frequency lock-in time. When the system is in a medium deviation state (e.g., 3° ​​< phase difference ≤ 8°), the reference parameters are kept constant to ensure a smooth transition to the resonant state and avoid overshoot. When the system is in a small deviation state (e.g., phase difference ≤ 3°), the frequency is reduced... Increase This enhances the suppression effect of the differential element, stabilizes the phase difference within the range of 0°±0.5°, achieves high-precision phase locking, and suppresses oscillations caused by minor disturbances.

[0084] (2) Dual-frequency tracking and coordinated control mechanism

[0085] This algorithm, in deep collaboration with phase-locked loop (PLL) automatic frequency tracking and the maximum current method, forms a two-stage control process: coarse-tuning positioning + fine-tuning phase-locking. In the coarse-tuning positioning stage, when the ultrasonic transducer is in the non-resonant range, the control module uses the maximum current method to scan the frequency, determining the resonant frequency point by finding the maximum value of the transducer's operating current, and quickly pulling the drive frequency to the resonant range. In this stage, the improved PID parameters are biased towards a "fast response" configuration, which, combined with the frequency sweep action, shortens the frequency lock time from ≥80 ms of the traditional PID to ≤50 ms. In the fine-tuning phase-locking stage, after entering the resonant range, it switches to PLL tracking, using the phase difference between the drive voltage and current... The PID input is used to adaptively adjust the time-varying parameters to stabilize the phase difference at 0° (resonance state), achieving a phase-locked loop accuracy of ≤0.05 kHz, ensuring that the ultrasonic transducer always operates at the resonant point with the highest electroacoustic conversion efficiency.

[0086] (3) Disturbance deviation feedforward compensation mechanism

[0087] To address external disturbances such as frequency drift, temperature rise, and load fluctuations that occur during the operation of ultrasonic transducers, this algorithm introduces a disturbance deviation compensation amount. The feedback monitoring module collects transducer temperature, vibration amplitude, and drive current / voltage signals in real time, and generates a data processing module. Directly superimposed on the PID control output In this system, the control quantity is corrected in advance, eliminating the need to wait for the integral stage to slowly eliminate the error. This mechanism can effectively compensate for control deviations caused by complex disturbances in clinical scenarios, avoid the decrease in cleaning efficiency or transducer overheating damage caused by frequency lockout, and improve system stability and reliability.

[0088] (4) Integral saturation inhibition mechanism

[0089] To avoid the integral saturation problem that is common in traditional PID controllers, this algorithm adds integral limiting and integral separation logic to the time-varying parameters: when the deviation exceeds a preset threshold (e.g., phase difference > 10°), the integral component is temporarily shut down (or the integral action is significantly reduced), and only proportional + derivative control is retained to prevent system overshoot or oscillation caused by integral accumulation; when the deviation enters a small range, the integral action is restored to gradually eliminate steady-state error and ensure that the system converges stably to the target resonance state.

[0090] (5) Composite waveform drive adaptation mechanism

[0091] This algorithm can dynamically adjust the PID parameters according to the ratio of the composite waveform (sine wave + square wave) to adapt to different clinical washing scenarios: when the proportion of the sine wave is high (e.g., a composite ratio of 7:3), the PID parameters are reduced. To ensure vibration stability and avoid mechanical damage to the root canal wall; when the square wave ratio is high (e.g., a composite ratio of 3:7), increase... To enhance anti-interference capabilities and suppress vibration fluctuations caused by higher harmonics of square waves, temperature compensation is also incorporated. Controlling the transducer temperature extends the service life of the equipment.

[0092] Example 2

[0093] Combination Figure 3 As shown, the composite waveform driving method of the ultrasonic transducer in the root canal irrigator of this embodiment is applied to the composite waveform driving device of the ultrasonic transducer in the root canal irrigator of Embodiment 1, and specifically includes the following steps:

[0094] Step S1: Parameter initialization: Set the driving parameters through the human-machine interface of the control module or the host computer. The driving parameters include the basic waveform type, basic waveform parameters, composite ratio, output power, frequency tracking accuracy and temperature threshold.

[0095] Specifically, in this embodiment, the basic waveform type is a sine wave + square wave, the sine wave frequency is 30 kHz ~ 50 kHz, the square wave frequency is 1 kHz ~ 5 kHz, the composite ratio of the two waveforms is 3:7 ~ 7:3, the output power is 0.5 W ~ 3.2 W, and the preferred temperature threshold is 60 ℃.

[0096] Step S2: Basic waveform generation. The control module outputs control commands to the signal generation module. The signal generation module generates two or more basic waveforms (such as a 30 kHz sine wave and a 2 kHz square wave) according to the set parameters. The control module then performs real-time calibration on the frequency and amplitude of the basic waveforms to ensure waveform stability.

[0097] Step S3: Composite Waveform Synthesis: The waveform composite module receives the basic waveform output by the signal generation module, and according to the composite ratio set by the control module, it superimposes and composites the basic waveform through the inverting addition circuit to generate the target composite waveform. The control module monitors and adjusts the parameters of the composite waveform in real time.

[0098] Step S4: Power Amplification and Impedance Matching: The power amplification module amplifies the target composite waveform signal. After the amplified composite waveform signal is matched by the impedance matching module, it is transmitted to the ultrasonic transducer through the interface module to drive the ultrasonic transducer to vibrate and realize the root canal cleaning operation.

[0099] Step S5: Real-time feedback and adjustment: The feedback monitoring module collects the vibration signal, temperature signal, current signal and voltage signal of the ultrasonic transducer in real time and transmits them to the control module. The control module performs frequency tracking, power adjustment and temperature protection processing on the signals.

[0100] In this embodiment, preferably, in step S5, the control module performs the following processing:

[0101] Frequency tracking: Calculate the phase difference between the voltage signal and the current signal, and use a combination of phase-locked automatic frequency tracking (zero-phase tracking or fixed-phase tracking) and the maximum current method to track the transducer's natural frequency drift in real time, and adjust the output frequency of the signal generation module to ensure that the transducer is always in a resonant state.

[0102] Power regulation: Based on the feedback current and voltage signals and the improved PID algorithm, the output power of the power amplifier module is dynamically adjusted to control the output power of the transducer to the set value. At the same time, the amplitude and composite ratio of the composite waveform are adjusted according to the vibration signal to optimize the washing effect.

[0103] Temperature protection: When the transducer temperature exceeds the set threshold, the control module automatically reduces the output power or stops driving. Normal driving will resume after the temperature drops to a safe range.

[0104] Step S6: End of irrigation: After the root canal irrigation operation is completed, a stop command is issued through the control module. The signal generation module stops generating the basic waveform, the power amplification module stops outputting, the feedback module stops detecting, and the entire drive device is in standby mode.

[0105] The composite waveform drive and method of the ultrasonic transducer in the root canal irrigator of this invention combines the advantages of different basic waveforms, balancing dynamic stability and impact force to improve the cleaning efficiency of root canal irrigation while avoiding mechanical damage to the root canal wall. Simultaneously, this invention integrates a precise frequency tracking and feedback adjustment mechanism to track the transducer's inherent frequency drift in real time and dynamically adjust the drive parameters, ensuring drive stability and extending the transducer's service life. This invention improves phase-locked loop accuracy and response speed through optimized control algorithms, achieving precise adjustment of the transducer's output power and waveform parameters to adapt to different root canal morphologies and irrigation needs.

[0106] Many specific details have been set forth in the foregoing description to provide a thorough understanding of the present invention. However, the above description is merely a preferred embodiment of the present invention, and the present invention can be implemented in many other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A composite waveform driving device for an ultrasonic transducer in a root canal irrigator, characterized in that: It includes a control module, a signal generation module, a waveform composite module, a power amplification module, an impedance matching module, and an interface module that are electrically connected in sequence, and also includes a feedback monitoring module that is electrically connected to both the control module and the interface module. The control module is used to receive the detection signal from the feedback monitoring module and output control commands to the signal generation module, waveform composite module and power amplification module to achieve precise adjustment of drive parameters and frequency tracking control. The signal generation module is used to generate various basic waveforms with programmable control over frequency, phase, and amplitude; The waveform composite module is used to receive two or more basic waveforms output by the signal generation module, and to superimpose and composite the basic waveforms according to the composite ratio set by the control module to generate the target composite waveform. The power amplification module is used to amplify the power of the target composite waveform, and the amplified signal power meets the driving requirements of the ultrasonic transducer. The impedance matching module is used to match the dynamic impedance of the ultrasonic transducer with the output impedance of the power amplifier module. The interface module is used to connect to the ultrasonic transducer assembly to realize the transmission of composite waveform drive signals and feedback of the working status of the ultrasonic transducer assembly. The feedback monitoring module is used to detect the working status of the ultrasonic transducer assembly in real time and transmit the detection signal to the control module.

2. The composite waveform driving device for the ultrasonic transducer in the root canal irrigator according to claim 1, characterized in that: The control module integrates a dual frequency tracking mechanism of phase-locked loop automatic frequency tracking and maximum current method, combined with an improved PID control algorithm. The control logic is as follows: in, To control the output, This is the time-varying proportional coefficient. This is a deviation signal. The time constant of the time-varying integral is... For the integral term of deviation, The time-varying differential time constant is... The rate of change of deviation This is the amount of compensation for disturbance deviation.

3. The composite waveform driving device for the ultrasonic transducer in the root canal irrigator according to claim 1, characterized in that: The signal generation module generates basic waveforms including sine waves and square waves. The frequency range of the sine waves is 30 kHz to 50 kHz, and the frequency range of the square waves is 1 kHz to 5 kHz. The amplitude adjustment accuracy reaches 12 bits, and the parameters of the output waveform are adjusted in real time by receiving instructions from the control module.

4. The composite waveform driving device for the ultrasonic transducer in the root canal irrigator according to claim 1, characterized in that: The waveform composite module uses an integrated operational amplifier to form an inverting adder circuit. The composite ratio of various basic waveforms can be adjusted in real time by the control module, with an adjustment range of 3:7 to 7:

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5. The composite waveform driving device for the ultrasonic transducer in the root canal irrigator according to claim 1, characterized in that: The power amplifier module is a linear amplifier with overcurrent and overvoltage protection. It uses a composite tube circuit structure to amplify the power of the composite waveform signal output by the waveform composite module. The amplified signal power ranges from 0.5 W to 3.2 W.

6. The composite waveform driving device for the ultrasonic transducer in the root canal irrigator according to claim 1, characterized in that: The impedance matching module consists of an LC resonant network and a π-type matching circuit.

7. The composite waveform driving device for the ultrasonic transducer in the root canal irrigator according to claim 1, characterized in that: The feedback monitoring module includes a voltage sampling unit, a current sampling unit, a temperature sampling unit, a vibration sampling unit, and a signal conditioning unit. After each sampling unit collects the corresponding signal, it is processed by the signal conditioning unit and outputs the phase difference, real-time power, operating temperature, and vibration amplitude signals to the control module for frequency tracking, power adjustment, and safety protection control.

8. The composite waveform driving device for the ultrasonic transducer in the root canal irrigator according to claim 1, characterized in that: One end of the interface module is electrically connected to the output of the power amplifier module, and the other end is detachably connected to the ultrasonic transducer of the root canal irrigator, and has signal isolation function.

9. A method for driving a composite waveform of an ultrasonic transducer in a root canal irrigator, characterized in that: A composite waveform driving device for the ultrasonic transducer in the root canal irrigator according to any one of claims 1-8 specifically includes the following steps: Step S1: Parameter initialization: Set the driving parameters through the human-machine interface of the control module or the host computer. The driving parameters include the basic waveform type, basic waveform parameters, composite ratio, output power, frequency tracking accuracy and temperature threshold. Step S2: Basic waveform generation. The control module outputs control commands to the signal generation module. The signal generation module generates two or more basic waveforms according to the set parameters, and the control module calibrates the frequency and amplitude of the basic waveforms in real time. Step S3: Composite Waveform Synthesis: The waveform composite module receives the basic waveform output by the signal generation module, and according to the composite ratio set by the control module, it superimposes and composites the basic waveform through the inverting addition circuit to generate the target composite waveform. The control module monitors and adjusts the parameters of the composite waveform in real time. Step S4: Power Amplification and Impedance Matching: The power amplification module amplifies the target composite waveform signal. After the amplified composite waveform signal is matched by the impedance matching module, it is transmitted to the ultrasonic transducer through the interface module to drive the ultrasonic transducer to vibrate and realize the root canal cleaning operation. Step S5: Real-time feedback and adjustment: The feedback monitoring module collects the vibration signal, temperature signal, current signal and voltage signal of the ultrasonic transducer in real time and transmits them to the control module. The control module performs frequency tracking, power adjustment and temperature protection processing on the signals. Step S6: End of irrigation: After the root canal irrigation operation is completed, a stop command is issued through the control module. The signal generation module stops generating the basic waveform, the power amplification module stops outputting, the feedback module stops detecting, and the entire drive device is in standby mode.

10. The composite waveform driving method for the ultrasonic transducer in the root canal irrigator according to claim 9, characterized in that: In step S5, the control module performs the following processing: Frequency tracking: The phase difference between the voltage signal and the current signal is calculated. A combination of phase-locked automatic frequency tracking and the maximum current method is used to track the transducer’s natural frequency drift in real time and adjust the output frequency of the signal generation module to ensure that the transducer is always in a resonant state. Power regulation: Based on the feedback current and voltage signals and the improved PID algorithm, the output power of the power amplifier module is dynamically adjusted to control the output power of the transducer to the set value. At the same time, the amplitude and composite ratio of the composite waveform are adjusted according to the vibration signal to optimize the washing effect. Temperature protection: When the transducer temperature exceeds the set threshold, the control module automatically reduces the output power or stops driving. Normal driving will resume after the temperature drops to a safe range.

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