A multi-medium adaptive ultrasonic aerosol generation system and control method

Abstract

The application discloses a multi-medium adaptive ultrasonic aerosol generating system and a control method, relates to the technical field of aerosol generating devices, and comprises an atomization cavity module, a refractive index online detection module, a medium identification and parameter mapping module, an adaptive transducer driving module, a concentration adaptive closed-loop control module and a medium switching and cleaning sequence module. The refractive index online detection module detects the refractive index of liquid medium in a liquid supply pipeline in real time and outputs a refractive index signal; the medium identification and parameter mapping module matches a pre-stored corresponding relationship according to the refractive index signal and outputs a medium configuration package; the adaptive transducer driving module restricts a resonance frequency search range by frequency bias, and drives a piezoelectric transducer by driving voltage and power modulation depth; the concentration adaptive closed-loop control module compares a corrected original concentration signal with a target concentration value to generate an adjustment signal after correction by a correction coefficient; and the medium switching and cleaning sequence module triggers a cleaning sequence when the refractive index variation exceeds a threshold value.

Description

Technical Field

[0001] This application relates to the field of aerosol generating devices, and in particular to a multi-media adaptive ultrasonic aerosol generating system and control method. Background Technology

[0002] In scenarios such as laser transmission characteristic simulation testing and optoelectronic countermeasures effect evaluation, researchers need to sequentially generate various aerosol media with different optical properties within the same closed test chamber to simulate the photoelectric transmission attenuation characteristics under different atmospheric environments. Commonly used aerosol media include deionized water with a refractive index of approximately 1.33, an aqueous solution of glycerol with a refractive index of approximately 1.40, and white mineral oil with a refractive index of approximately 1.47. The viscosity differences of these media can reach tens of times, and their optical properties vary significantly.

[0003] In related technologies, to achieve stable aerosol generation in a specific medium, multiple control methods are typically employed in parallel: on the one hand, impedance matching is used to operate the piezoelectric transducer near its resonant frequency to obtain optimal atomization efficiency; on the other hand, a light-scattering concentration sensor monitors the aerosol concentration, and a PID control loop is used to adjust the transducer drive power or liquid supply rate to stabilize the concentration near the target value; simultaneously, for particle size requirements, open-loop control is performed by adjusting a single parameter such as gas pressure or transducer power. Each of these control methods establishes its own feedback or regulation loop based on the physical characteristics of the controlled object, and operates independently of the others.

[0004] When switching the same aerosol generator from producing one medium to producing another medium with significantly different refractive indices and viscosities, the limitations of this approach become apparent: the resonant frequency and impedance characteristics of the transducer do not match the physical properties of the new medium, causing the original impedance matching loop to potentially lock onto an incorrect resonant peak or repeatedly detuned, resulting in a sharp drop in atomization efficiency; the photoelectric response signal of the concentration sensor is closely related to the particle refractive index, and the original sensor calibration coefficients calibrated for the previous medium are no longer applicable, causing the closed-loop PID loop to actually control an incorrectly estimated concentration value, resulting in uncontrollable or even divergent control effects; the original particle size adjustment methods also fail to consider changes in medium viscosity and surface tension, causing the droplet particle size generated under the same control parameters to deviate significantly from expectations. The failures of the aforementioned control loops are not caused by a single factor. The root cause lies in the fact that the references and coefficients of all control subunits, such as transducer frequency search, concentration signal conversion, and particle size open-loop adjustment, are implicitly bound to the physical properties of a specific medium. Without a unified, synchronous cross-dimensional parameter update mechanism, these independent control loops not only fail to work collaboratively under new medium conditions but may also exacerbate system instability due to mutual coupling. Consequently, in test procedures requiring medium switching on the same device, manual intervention is necessary, and a long transition time exists. Furthermore, the initial atomized components after switching are often impure due to residual liquid film contamination. This series of problems makes related multi-medium test procedures inefficient, with poor data reliability, and unable to meet the demands for automated and high-efficiency testing. Summary of the Invention

[0005] The purpose of this application is to provide a multi-media adaptive ultrasonic aerosol generation system and control method, which solves the problems of system instability, decreased accuracy and low efficiency caused by control dimension mismatch in multi-media testing scenarios. It realizes automatic completion of media switching and parameter adaptation on a single hardware platform without manual intervention, so that the system can quickly output aerosols that meet the expected particle size and concentration requirements in a stable state after switching, thereby ensuring the reliability and high efficiency of the multi-media continuous testing process.

[0006] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a multi-media adaptive ultrasonic aerosol generation system, comprising: An atomizing chamber module, the atomizing chamber module having a chamber for containing a liquid medium, a piezoelectric transducer installed at the bottom of the chamber, and a mist outlet disposed at the top of the chamber; An online refractive index detection module is installed on the liquid supply pipeline before the liquid medium enters the atomizing cavity module. It is used to detect the refractive index of the liquid medium flowing through the liquid supply pipeline in real time and output a refractive index signal. The medium identification and parameter mapping module is communicatively connected to the online refractive index detection module. It is used to store the correspondence between the refractive index ranges of various standard liquid media and the medium configuration package, and to match the correspondence according to the refractive index signal to output the medium configuration package corresponding to the current liquid media. The medium configuration package includes at least the transducer drive voltage, frequency bias, power modulation depth and concentration sensor correction coefficient, refractive index, and particle size control coefficient. An adaptive transducer driving module is connected to the medium identification and parameter mapping module and the piezoelectric transducer, respectively. It is used to receive the transducer driving voltage, the frequency bias and the power modulation depth, constrain the resonant frequency search range with the frequency bias, and drive the piezoelectric transducer to work with the transducer driving voltage and the power modulation depth. The concentration adaptive closed-loop control module is connected to the medium identification and parameter mapping module and the light scattering concentration sensor located downstream of the mist outlet. It is used to receive the correction coefficient of the concentration sensor and the original concentration signal output by the light scattering concentration sensor, correct the original concentration signal using the correction coefficient to obtain the corrected concentration value, and generate an adjustment signal based on the comparison result between the corrected concentration value and the obtained target concentration value, and output it to the adaptive transducer drive module. A medium switching cleaning sequence module is connected to the online refractive index detection module and the atomizing cavity module. It is used to monitor the change in the refractive index signal. When the change exceeds a preset threshold, a cleaning sequence is triggered to control the system to perform aerosol generation for the new liquid medium. The cleaning sequence includes at least a purging operation, a high-frequency oscillation operation, and a refractive index confirmation operation.

[0007] Secondly, this application provides a multi-media adaptive ultrasonic aerosol generation control method, including: The refractive index of the liquid medium flowing through the liquid supply pipeline is detected in real time using an online refractive index detection module installed on the liquid supply pipeline, and a refractive index signal is output. The medium identification and parameter mapping module acquires the refractive index signal, matches the refractive index signal with the pre-stored correspondence between the refractive index ranges of various standard liquid media and the medium configuration package, and outputs the medium configuration package corresponding to the current liquid media; the medium configuration package includes at least the transducer drive voltage, frequency bias, power modulation depth and concentration sensor correction coefficient, refractive index, and particle size control coefficient. The adaptive transducer drive module receives the transducer drive voltage, the frequency bias, and the power modulation depth, constrains the resonant frequency search range with the frequency bias, and drives the piezoelectric transducer at the bottom of the atomizing cavity module to work with the transducer drive voltage and the power modulation depth, so as to atomize the liquid medium in the atomizing cavity module. The concentration adaptive closed-loop control module acquires the original concentration signal output by the light scattering concentration sensor located downstream of the mist outlet, acquires the concentration sensor correction coefficient from the medium identification and parameter mapping module, and acquires the target concentration value input externally. The original concentration signal is corrected using the concentration sensor correction coefficient to obtain the corrected concentration value. An adjustment signal is generated based on the comparison result between the corrected concentration value and the target concentration value. The adjustment signal is output to the adaptive transducer drive module to adjust the drive power or liquid supply rate of the piezoelectric transducer. The medium switching cleaning sequence module monitors the change in the refractive index signal. When the change exceeds a preset threshold, a cleaning sequence is triggered to perform aerosol generation for the new liquid medium. The cleaning sequence includes at least a purging operation, a high-frequency oscillation operation, and a refractive index confirmation operation.

[0008] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a multi-media adaptive ultrasonic aerosol generation system and control method. The system outputs the refractive index signal of the liquid medium flowing through the liquid supply pipeline in real time through an online refractive index detection module. The medium identification and parameter mapping module matches the refractive index signal with the pre-stored correspondence between the refractive index range and the medium configuration package, and outputs a medium configuration package corresponding to the current liquid medium, which includes transducer drive voltage, frequency offset, power modulation depth and concentration sensor correction coefficient, refractive index, and particle size control coefficient. This solves the problems in related technologies where the reference and coefficients of each control subunit are implicitly bound to the physical properties of a specific medium, and the lack of a unified update mechanism after medium switching leads to the inability of independent control loops to work together or even mutual coupling, which aggravates system instability. The system achieves multi-dimensional parameter collaborative adaptation with refractive index as a unified a priori parameter and synchronously updating transducer drive parameters and sensor correction coefficients at the moment of medium switching.

[0009] By using the adaptive transducer drive module to constrain the resonant frequency search range with the frequency bias and to drive the piezoelectric transducer with the transducer drive voltage and the power modulation depth, the problem of impedance matching loop locking to the wrong resonant peak or repeated detuning leading to a sharp drop in atomization efficiency caused by changes in the acoustic impedance parameters of the new medium is solved in related technologies. This achieves rapid and accurate resonant locking of the transducer under new medium conditions.

[0010] The concentration adaptive closed-loop control module receives the correction coefficient of the concentration sensor and the original concentration signal output by the light scattering concentration sensor. It uses the correction coefficient of the concentration sensor to correct the original concentration signal to obtain the corrected concentration value. Based on the comparison between the corrected concentration value and the target concentration value, it generates an adjustment signal and outputs it to the adaptive transducer drive module. This solves the problems in related technologies, such as the significant deviation of the light scattering sensor output from the same sensor in concentration estimation due to the difference in refractive index of different media, and the uncontrollable or divergent control effect caused by the incorrectly estimated concentration value in the actual control of the closed-loop PID loop. It achieves stable maintenance of the concentration closed-loop control accuracy under cross-media conditions.

[0011] The change in the refractive index signal is monitored by the medium switching cleaning sequence module. When the change exceeds a preset threshold, a cleaning sequence including purging operation, high-frequency oscillation operation and refractive index confirmation operation is triggered to control the system to perform aerosol generation for the new liquid medium. This solves the problems in related technologies where residual liquid film during medium switching contaminates subsequent media, resulting in impure aerosol composition in the early stage of atomization, as well as the need for manual intervention and long transition time during switching. It realizes the automated execution of the medium switching process and the rapid recovery of atomization purity after switching. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is an overall framework diagram of the multi-media adaptive ultrasonic aerosol generation system provided in Embodiment 1 of this application; Figure 2 This is a schematic diagram of the optical path principle of the online refractive index detection module provided in Embodiment 1 of this application; Figure 3 This is a flowchart of media identification and parameter mapping provided in Embodiment 1 of this application; Figure 4 This is a schematic diagram of the frequency search constraint of the adaptive transducer drive module provided in Embodiment 1 of this application; Figure 5 The concentration correction factor provided in Embodiment 1 of this application K With refractive index n A schematic diagram of the calibration curve; Figure 6 This is a timing diagram of the media switching cleaning sequence provided in Embodiment 1 of this application. Detailed Implementation

[0014] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0015] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] Example 1 This application provides a multi-media adaptive ultrasonic aerosol generation system, suitable for scenarios such as photoelectric countermeasures simulation and testing, laser transmission characteristic simulation and testing, and aerosol optical property research. The specific embodiments of this application are described in detail below with reference to the accompanying drawings.

[0017] The multi-media adaptive ultrasonic aerosol generation system of this application includes an atomization cavity module, an online refractive index detection module, a media identification and parameter mapping module, an adaptive transducer drive module, a concentration adaptive closed-loop control module, and a media switching cleaning sequence module. These modules work collaboratively to achieve unified adaptive atomization control for multiple liquid media. The overall system architecture is as follows: Figure 1 As shown.

[0018] The atomizing chamber module includes a chamber for containing liquid media, a piezoelectric transducer installed at the bottom of the chamber, and a mist outlet located at the top of the chamber.

[0019] The online refractive index detection module is installed on the liquid supply pipeline before the liquid medium enters the atomization chamber module. It is used to detect the refractive index of the liquid medium flowing through the liquid supply pipeline in real time and output the refractive index signal. Figure 2 This is a schematic diagram of the optical path principle of the online refractive index detection module, demonstrating the method for detecting the critical angle of total internal reflection.

[0020] The medium identification and parameter mapping module is communicatively connected to the online refractive index detection module. It is used to store the correspondence between the refractive index ranges of various standard liquid media and the medium configuration package, and to match the correspondence according to the refractive index signal to output the medium configuration package corresponding to the current liquid media. The medium configuration package includes at least the transducer drive voltage, frequency bias, power modulation depth and concentration sensor correction coefficient, refractive index n, and particle size control coefficient kd. Figure 3 This is a flowchart of the medium identification and parameter mapping process, illustrating the mapping logic from refractive index readings to the medium configuration package.

[0021] An adaptive transducer drive module is connected to the medium identification and parameter mapping module and the piezoelectric transducer, respectively. It is used to receive the transducer drive voltage, frequency bias and power modulation depth, constrain the resonant frequency search range with the frequency bias, and drive the piezoelectric transducer to work with the transducer drive voltage and power modulation depth. Figure 4 This is a schematic diagram of the frequency search constraint for the adaptive transducer driver module, comparing the differences in search range with and without prior medium constraints.

[0022] The concentration adaptive closed-loop control module is connected to the medium identification and parameter mapping module and the light scattering concentration sensor located downstream of the mist outlet. It receives the correction coefficient of the concentration sensor and the original concentration signal output by the light scattering concentration sensor, corrects the original concentration signal using the correction coefficient to obtain the corrected concentration value, and generates an adjustment signal based on the comparison between the corrected concentration value and the acquired target concentration value, which is then output to the adaptive transducer drive module. Figure 5 Concentration correction factor K With refractive index n The calibration curves (three-point calibration with deionized water, 50:50 glycerol / water, and white mineral oil).

[0023] The medium switching cleaning sequence module is connected to the online refractive index detection module and the atomization chamber module. It is used to monitor the change in refractive index signal. When the change exceeds a preset threshold, the cleaning sequence is triggered to control the system to perform aerosol generation for the new liquid medium. The cleaning sequence includes at least purging operation, high-frequency oscillation operation and refractive index confirmation operation. Figure 6 The timing diagram for the medium switching cleaning sequence shows the time allocation of the three steps: purging, high-frequency oscillation, and refractive index confirmation.

[0024] Furthermore, the online refractive index detection module includes a light-emitting element, a flow cell, and a photoelectric receiving array arranged sequentially along the optical path. The light-emitting element has a light source wavelength of 880 nanometers. The flow cell is connected in series in the liquid supply pipeline for the liquid medium to flow through. The photoelectric receiving array is used to receive the light after it is refracted by the liquid medium in the flow cell and output an electrical signal corresponding to the refractive index. The detection accuracy of the online refractive index detection module is ±0.002, and the response time is less than 1 second.

[0025] Furthermore, the purging operation performed by the media switching cleaning sequence module is as follows: the inlet valve of the liquid supply line is closed, and the piezoelectric transducer is driven at maximum power to discharge the residual liquid medium in the cavity; the high-frequency oscillation operation is as follows: after the purging operation is completed, the adaptive transducer drive module is controlled to excite the piezoelectric transducer to oscillate with a high-frequency pulse higher than the standard operating frequency of the piezoelectric transducer. The frequency of the high-frequency pulse is 105% to 110% of the standard operating frequency, and the excitation duration is 3 to 10 seconds; the refractive index confirmation operation is as follows: after the high-frequency oscillation operation is completed, the liquid supply line is controlled to inject new medium into the atomization cavity module, and the switching is confirmed to be complete after the refractive index reading of the online refractive index detection module stabilizes.

[0026] Furthermore, the concentration sensor correction coefficient and the refractive index of the liquid medium satisfy a quadratic polynomial fitting relationship: ; in, This is the correction factor for the concentration sensor; The refractive index of the liquid medium; 、 、 These are calibration coefficients, determined through factory calibration tests.

[0027] Furthermore, the medium configuration package also includes the viscosity, density, and surface tension of the liquid medium; the system also includes a particle size estimation module, which is connected to both the medium identification and parameter mapping module and the adaptive transducer drive module; the particle size estimation module is used to: receive the viscosity, density, surface tension, transducer drive voltage, and power modulation depth output by the medium identification and parameter mapping module, as well as the resonant frequency of the piezoelectric transducer, and based on the Rayleigh-Taylor instability theory, calculate the particle size based on the received viscosity, density, surface tension, transducer drive voltage, power modulation depth, and resonant frequency. Estimate the particle size of the current liquid medium after atomization; calculate the power modulation depth correction amount based on the current liquid medium atomization particle size and the obtained target particle size, and update the power modulation depth using the power modulation depth correction amount before outputting it to the adaptive transducer drive module; after re-driving the piezoelectric transducer using the updated power modulation depth, return to the step "estimate the current liquid medium atomization particle size based on the received viscosity, density, surface tension, transducer drive voltage, power modulation depth and resonant frequency, and repeat the iteration until the deviation between the current liquid medium atomization particle size and the target particle size converges to the preset range".

[0028] Furthermore, the particle size is calculated as follows: ; in, The particle size after atomization; The wavelength of the atomized surface droplets; This is the particle size control coefficient; Surface tension; Density; The electromechanical coupling coefficient of the piezoelectric transducer; This is the transducer drive voltage; Power modulation depth; is the resonant frequency of the piezoelectric transducer.

[0029] Furthermore, the calculation method for the power modulation depth correction is as follows: ; in, This is the feedforward gain coefficient; This refers to the particle size after the current medium is atomized; Target particle size; The reference power modulation depth in the current media configuration package.

[0030] Furthermore, the power modulation depth is updated as follows: ; in, The updated power modulation depth; This is the lower limit of the power modulation depth; This represents the upper limit of the power modulation depth. Indicates will Constraints to Within the range.

[0031] Furthermore, the medium identification and parameter mapping module supports the storage of custom medium configuration packages. Specifically, the refractive index, viscosity, density, and surface tension of a new liquid medium are input through the host computer software. The medium identification and parameter mapping module calculates the transducer drive voltage, frequency bias, power modulation depth, and concentration sensor correction coefficient corresponding to the new liquid medium based on the built-in property-parameter mapping model. The calculated parameters are then combined with the input refractive index, viscosity, density, and surface tension to form a complete medium configuration package, which is then stored in the parameter library.

[0032] Furthermore, the system communicates with an external testing system via a bus communication protocol to receive media switching instructions and target concentration values ​​issued by the external testing system, and to report system status, concentration data, and alarm information to the external testing system; the media switching cleaning sequence module triggers the cleaning sequence when it receives the media switching instruction, and sends a ready signal to the external testing system after the cleaning sequence is completed.

[0033] Furthermore, to ensure the clarity and feasibility of the collaborative work of each module, the system will be uniformly described below from three dimensions: physical pipeline connection, electrical connection, and signal flow.

[0034] In terms of physical piping connections, the liquid medium is injected into the system piping from an external storage container via an inlet pump, flowing sequentially through the detection chamber of the online refractive index detection module, the inlet control solenoid valve, and finally into the atomization chamber module. This detection chamber is a flow cell for a total internal reflection refractometer, connected in series in the supply pipeline for the liquid medium to flow through. A piezoelectric transducer is installed at the bottom of the atomization chamber, and a G1 / 2 atomization outlet is located at the top. The atomized aerosol is delivered to the external test chamber through the outlet. The media switching and cleaning sequence module controls the opening and closing of the inlet and outlet valves to achieve chamber emptying and cleaning operations.

[0035] In terms of electrical connection, the adaptive transducer drive module is electrically connected to the piezoelectric transducer through a power drive circuit, providing a PWM (Pulse Width Modulation) modulated drive voltage. V 0 The driving voltage is frequency biased. Δf The constrained AFT (Adaptive Frequency Tracking) signal is used for tracking. The LED (Light Emitting Diode) light source driver circuit and photodetector array of the online refractive index detection module are connected to the analog input port of the controller via signal lines. This controller is a PLC (Programmable Logic Controller) / PAC (Programmable Automation Controller) platform. The concentration sensor is installed in the downstream pipeline of the mist outlet and communicates with the controller via an RS485 bus. The temperature sensor (Pt1000 type) is attached to the transducer base and connected to the controller's temperature acquisition channel. The solenoid valve and inlet pump are driven by the controller's digital output port.

[0036] In terms of signal flow, the system signal flow presents a closed-loop structure of "detection → identification → configuration → execution → feedback". The online refractive index detection module outputs the refractive index in real time. n Signal to medium identification and parameter mapping module. The medium identification and parameter mapping module will map the refractive index... n Matching with the pre-stored lookup table, the output medium configuration package is sent to the adaptive transducer drive module, the concentration adaptive closed-loop control module, and the medium switching cleaning sequence module, respectively; this medium configuration package contains physical property parameters (refractive index). n Viscosity or ,density r Surface tension s ) and control parameters (transducer drive voltage) V 0 Frequency bias Δf Power modulation depth m Concentration sensor correction factor K and particle size control coefficient The adaptive transducer drive module is frequency biased. Δf Constrain the AFT search range with transducer drive voltage V 0 and power modulation depth m Drive the piezoelectric transducer to work, and simultaneously output the actual resonant frequency. f res Feedback signals are sent to the controller for status monitoring. The concentration adaptive closed-loop control module receives the raw count value from the concentration sensor, multiplies it by the concentration sensor correction coefficient K to obtain the true concentration, and then uses the ratio of this to the target concentration to output a PWM duty cycle adjustment signal via a PID (Proportional-Integral-Derivative) algorithm to the adaptive transducer drive module, thus achieving concentration closed-loop control. The media switching cleaning sequence module monitors the rate of refractive index change. Δn / D t When | Δn At a concentration of 0.01, a cleaning sequence is triggered. The control system coordinates the inlet valve, outlet valve, and transducer high-frequency drive signals to perform three steps: evacuation, oscillation, and confirmation. Upon completion, a "switching ready" signal is sent to the media identification and parameter mapping module, triggering the loading of the new media configuration package. The controller communicates with the external host computer / test system via a Modbus RTU (Modbus Remote Terminal Unit) bus, receiving media switching commands and target concentration setpoints, and reporting system status, concentration data, and alarm information.

[0037] The aforementioned physical connections and signal flow ensure complete coupling of each module at the piping, electrical, and communication levels, forming a closed-loop control chain from media detection to atomization output.

[0038] Example 2 Based on the same inventive concept, this application also provides a multi-media adaptive ultrasonic aerosol generation control method applied to the aforementioned multi-media adaptive ultrasonic aerosol generation system. The solution provided by this control method is similar to the solution described in the above system; therefore, the specific limitations in one or more control method embodiments provided below can be found in the system limitations described above, and will not be repeated here.

[0039] In one exemplary embodiment, a multi-media adaptive ultrasonic aerosol generation control method is provided, comprising: The refractive index of the liquid medium flowing through the liquid supply pipeline is detected in real time by an online refractive index detection module installed on the liquid supply pipeline, and the refractive index signal is output.

[0040] The medium identification and parameter mapping module acquires the refractive index signal, matches the pre-stored correspondence between the refractive index ranges of various standard liquid media and the medium configuration package based on the refractive index signal, and outputs the medium configuration package corresponding to the current liquid media; the medium configuration package includes at least the transducer drive voltage, frequency bias, power modulation depth and concentration sensor correction coefficient, refractive index n, and particle size control coefficient kd.

[0041] The adaptive transducer drive module receives the transducer drive voltage, frequency bias, and power modulation depth. It uses the frequency bias to constrain the resonant frequency search range and uses the transducer drive voltage and power modulation depth to drive the piezoelectric transducer at the bottom of the atomizing cavity module to work, thereby atomizing the liquid medium inside the atomizing cavity module.

[0042] The concentration adaptive closed-loop control module acquires the original concentration signal output by the light scattering concentration sensor located downstream of the mist outlet, acquires the concentration sensor correction coefficient from the medium identification and parameter mapping module, and acquires the target concentration value input from the outside. It then uses the concentration sensor correction coefficient to correct the original concentration signal to obtain the corrected concentration value. Based on the comparison between the corrected concentration value and the target concentration value, it generates an adjustment signal and outputs the adjustment signal to the adaptive transducer drive module to adjust the drive power of the piezoelectric transducer or the liquid supply rate.

[0043] The medium switching cleaning sequence module monitors the change in refractive index signal. When the change exceeds a preset threshold, a cleaning sequence is triggered to perform aerosol generation for the new liquid medium. The cleaning sequence includes at least a purging operation, a high-frequency oscillation operation, and a refractive index confirmation operation.

[0044] Furthermore, the purging operation performed by the media switching cleaning sequence module is as follows: the inlet valve of the liquid supply line is closed, and the piezoelectric transducer is driven at maximum power to discharge the residual liquid medium in the cavity; the high-frequency oscillation operation is as follows: after the purging operation is completed, the adaptive transducer drive module is controlled to excite the piezoelectric transducer to oscillate with a high-frequency pulse higher than the standard operating frequency of the piezoelectric transducer. The frequency of the high-frequency pulse is 105% to 110% of the standard operating frequency, and the excitation duration is 3 to 10 seconds; the refractive index confirmation operation is as follows: after the high-frequency oscillation operation is completed, the liquid supply line is controlled to inject new medium into the atomization cavity module, and the switching is confirmed to be complete after the refractive index reading of the online refractive index detection module stabilizes.

[0045] Example 3 This embodiment illustrates the workflow of the system in this application embodiment under multi-media switching scenarios by describing the complete process of switching from deionized water to a 50:50 glycerol / water medium.

[0046] Initially, the atomizing chamber contains deionized water. The online refractive index detection module uses the principle of total internal reflection refractometer, illuminating the liquid with an LED light source, detecting changes in the critical angle, and outputting the liquid's refractive index n in real time. The LED light source has a wavelength of 880 nanometers, consistent with the wavelength of the concentration sensor. The online refractive index detection module has a detection accuracy of ±0.002 and a response time of less than 1 second. At this point, the online refractive index detection module reading n = 1.333, and the system loads medium configuration package ①. This medium configuration package ① contains two sets of data: physical property parameters and control parameters. The physical property parameters include the refractive index... n =1.333, viscosity or =1.0 mPa·s, density r =998 kg / m 3 Surface tension s =72.8 mN / m; control parameters include transducer drive voltage V 0 =48V, frequency bias Δf =0, power modulation depth m =0.85, Concentration sensor correction factor K =1.00. The concentration sensor uses a 90° light scattering type with an 880nm wavelength infrared LED source. Its original output value is a 16-bit digital count value proportional to the intensity of the scattered light, with a range of 0 to 65535. This count value is quantized by the sensor's internal ADC (Analog-to-Digital Converter) and then transmitted to the controller via the Modbus RTU interface. The original output count value of the concentration sensor is 2048. After correction, the true concentration = 1.00 × 2048 = 2048, which corresponds to 0.5 g / m³. 3 The PLC controller uses PID closed-loop control based on the corrected concentration value, with a target concentration output of 0.5 g / m³. 3 The measured deviation is ≤±4%.

[0047] When the operator injects a 50:50 glycerol / water solution into the media inlet, the refractive index sensor detects the refractive index. n The mutation value increased from 1.333 to 1.395, a change of | ΔnThe value of |=0.062 exceeds the preset threshold of 0.01, triggering the media switching cleaning sequence module to automatically initiate a cleaning sequence. This cleaning sequence includes a purging operation, a high-frequency oscillation operation, and a refractive index confirmation operation. The purging operation involves closing the inlet valve of the liquid supply line and driving the piezoelectric transducer at maximum power to drain the residual liquid medium from the chamber for approximately 8 seconds. The high-frequency oscillation operation involves, after the purging operation, controlling the adaptive transducer drive module to excite the piezoelectric transducer to oscillate with a high-frequency pulse higher than the standard operating frequency of the transducer. The frequency of this high-frequency pulse is 1.85MHz (approximately 108.8% of the standard operating frequency of 1.7MHz), and the excitation duration is 5 seconds, utilizing the resonant thermal effect to evaporate the residual liquid film on the transducer surface. The refractive index confirmation operation involves, after the high-frequency oscillation operation, controlling the liquid supply line to inject a small amount of glycerol / water solution into the atomization chamber module. Once the refractive index reading of the online refractive index detection module stabilizes at 1.395±0.003, the switching is confirmed to be complete.

[0048] After the switch is complete, the system loads medium configuration package ②. This medium configuration package ② contains two sets of data: physical property parameters and control parameters. The physical property parameters include the refractive index. n =1.395, viscosity or =6.0 mPa·s, density r =1130 kg / m 3 Surface tension s =63 mN / m; control parameters include transducer drive voltage. V 0 =52V, frequency offset Δf =+1.2kHz, power modulation depth m =0.92, Concentration sensor correction factor K =0.88. The transducer resonant frequency search was completed and locked within ±2kHz in approximately 3 seconds. The concentration correction coefficient was automatically updated to 0.88. The original output count value of the concentration sensor was 2320. The corrected true concentration = 0.88 × 2320 = 2042, corresponding to 0.5 g / m³. 3 The PLC controller continues to perform PID control based on the corrected actual concentration value, with a target concentration output of 0.5 g / m³. 3 The measured deviation is ≤±5%. The entire switching process takes approximately 20 seconds.

[0049] Example 4 This embodiment illustrates the parameter self-calibration process of the system in this application embodiment when expanding to new media types by describing the complete process of customizing the propylene glycol aqueous solution media configuration package.

[0050] The operator inputs the physical properties of the new liquid medium, including refractive index, through the host computer software. n=1.42 (propylene glycol aqueous solution), viscosity or =8 mPa·s, density r =1050 kg / m 3 Surface tension s =55 mN / m. The above physical properties constitute the physical properties section (refractive index) of the medium configuration package. n Viscosity or ,density r Surface tension s The medium identification and parameter mapping module supports the storage of custom medium configuration packages. Specifically, the refractive index, viscosity, density, and surface tension of a new liquid medium are input via the host computer software. The module calculates the transducer drive voltage, frequency offset, power modulation depth, and concentration sensor correction coefficient corresponding to the new liquid medium based on the built-in property-parameter mapping model. The calculated parameters are then combined with the input refractive index, viscosity, density, and surface tension to form a complete medium configuration package, which is stored in the parameter library. Specifically, the system calculates the control parameters based on the built-in property-parameter mapping model, including the transducer drive voltage. V 0 =53V, frequency bias Δf =+1.6kHz, power modulation depth m =0.90, Concentration sensor correction factor K =0.86. Combine the physical property parameters and control parameters into a complete media configuration package ③ and store it in the parameter library.

[0051] During the subsequent calibration run (lasting 30 minutes), the online optimization algorithm adjusted the control parameters (transducer drive voltage) based on the actual atomization effect. V 0 Power modulation depth m Concentration sensor correction factor K Self-correction is performed, and the final parameter deviation is ≤±3%. Physical property parameters (refractive index) n Viscosity or ,density r Surface tension s It remains constant during operation (or is finely adjusted with temperature), providing a baseline input for particle size estimation and concentration correction.

[0052] Example 5 Taking a 50:50 glycerol / water medium as an example, the particle size estimation module in this embodiment of the application is based on the Rayleigh-Taylor instability theory to estimate particle size. Estimation and power modulation depth The complete algorithm flow for adjustment is explained.

[0053] The particle size estimation module is connected to both the medium identification and parameter mapping module and the adaptive transducer drive module. The particle size estimation module receives the viscosity output from the medium identification and parameter mapping module. ,density Surface tension Transducer drive voltage Power modulation depth and the resonant frequency of the receiving piezoelectric transducer. Based on the received viscosity ,density Surface tension Transducer drive voltage Power modulation depth and resonant frequency Estimate the particle size of the current liquid medium after atomization .

[0054] The known physical properties of medium configuration package ② are: surface tension. s =0.063 N / m, density r =1130 kg / m 3 Control parameters: Transducer drive voltage V 0 =52V, power modulation depth m =0.92, piezoelectric transducer resonant frequency f =1.7012MHz (reference 1.7MHz + frequency offset 1.2kHz). Transducer electromechanical coupling coefficient. =3.2×10 -6 m / V 2 This value is determined by factory calibration. Particle size control coefficient =0.34.

[0055] Step 1: Calculate the transducer surface acceleration The calculation formula is: ; in, For the transducer surface acceleration, The electromechanical coupling coefficient of the piezoelectric transducer is... This is the transducer drive voltage. For power modulation depth, is the resonant frequency of the piezoelectric transducer.

[0056] Step 2: Calculate the Rayleigh-Taylor droplet wavelength The calculation formula is: ; in, The wavelength of the atomized surface droplets. For surface tension, For density, This refers to the surface acceleration of the transducer.

[0057] Step 3: Estimate particle size D 50 The calculation formula is: ; in, The particle size after atomization; The wavelength of the atomized surface droplets; This is the particle size control coefficient; Surface tension; Density; The electromechanical coupling coefficient of the piezoelectric transducer; This is the transducer drive voltage; Power modulation depth; This is the resonant frequency of the piezoelectric transducer. Referring to typical data, the typical 50:50 glycerol / water ratio... The estimated value is 3 to 6 μm, which is too high, indicating that the current... m =0.92 corresponds to a low ultrasonic intensity, which needs to be increased. m To increase acceleration a , reduce and D 50 .

[0058] Step 4: The particle size estimation module estimates the particle size after atomization of the current liquid medium. D 50 The power modulation depth correction is calculated based on the comparison results with the target particle size. Δm The calculation formula is: ; in, This is the feedforward gain coefficient; This refers to the particle size after the current medium is atomized; Target particle size; The reference power modulation depth in the current media configuration package.

[0059] Set target particle size =5μm, feedforward gain coefficient =0.15.

[0060] Step 5: Utilize power modulation depth correction amount Δm The power modulation depth is updated using the following formula: ; in, The updated power modulation depth; This is the lower limit of the power modulation depth; This represents the upper limit of the power modulation depth. Indicates will Constraints to Within the range. Due to the correction... Once the upper limit of 1.00 is reached, the system will... m =1.00 Redrive the transducer. After the particle size estimation module redrives the piezoelectric transducer using the updated power modulation depth, it returns to the step "Estimate the particle size of the current liquid medium after atomization based on the received viscosity, density, surface tension, transducer drive voltage, power modulation depth, and resonant frequency". D 50 ", and repeat the iteration until the particle size is reached. D 50 The deviation from the target particle size converges to the preset range.

[0061] After the particle size estimation module re-drives the piezoelectric transducer using the updated power modulation depth, it performs the particle size estimation again. D 50 The estimation and calculation of the power modulation depth correction amount are repeated iteratively until the particle size is reached. D 50 The deviation from the target particle size converges to a preset range. After 2 to 3 iterations, the particle size... D 50 It converges to a range of 5±0.8μm, achieving cross-medium particle size consistency compensation.

[0062] The above algorithm process is also applicable to deionized water ( s =0.0728 N / m, r =998 kg / m 3 ) and white mineral oil ( s =0.030 N / m, r =865 kg / m 3 Different media, such as [unclear], can automatically adjust the power modulation depth. m To adjust the particle size of each medium D 50 The output approximates the target value, ensuring consistent particle size control across media.

[0063] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0064] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A multi-media adaptive ultrasonic aerosol generation system, characterized in that, The system includes: An atomizing chamber module, the atomizing chamber module having a chamber for containing a liquid medium, a piezoelectric transducer installed at the bottom of the chamber, and a mist outlet disposed at the top of the chamber; An online refractive index detection module is installed on the liquid supply pipeline before the liquid medium enters the atomizing cavity module. It is used to detect the refractive index of the liquid medium flowing through the liquid supply pipeline in real time and output a refractive index signal. The medium identification and parameter mapping module is communicatively connected to the online refractive index detection module. It is used to store the correspondence between the refractive index ranges of various standard liquid media and the medium configuration package, and to match the correspondence according to the refractive index signal to output the medium configuration package corresponding to the current liquid media. The medium configuration package includes at least the transducer drive voltage, frequency bias, power modulation depth and concentration sensor correction coefficient, refractive index, and particle size control coefficient. An adaptive transducer driving module is connected to the medium identification and parameter mapping module and the piezoelectric transducer, respectively. It is used to receive the transducer driving voltage, the frequency bias and the power modulation depth, constrain the resonant frequency search range with the frequency bias, and drive the piezoelectric transducer to work with the transducer driving voltage and the power modulation depth. The concentration adaptive closed-loop control module is connected to the medium identification and parameter mapping module and the light scattering concentration sensor located downstream of the mist outlet. It is used to receive the correction coefficient of the concentration sensor and the original concentration signal output by the light scattering concentration sensor, correct the original concentration signal using the correction coefficient to obtain the corrected concentration value, and generate an adjustment signal based on the comparison result between the corrected concentration value and the obtained target concentration value, and output it to the adaptive transducer drive module. A medium switching cleaning sequence module is connected to the online refractive index detection module and the atomizing cavity module. It is used to monitor the change in the refractive index signal. When the change exceeds a preset threshold, a cleaning sequence is triggered to control the system to perform aerosol generation for the new liquid medium. The cleaning sequence includes at least a purging operation, a high-frequency oscillation operation, and a refractive index confirmation operation.

2. The multi-media adaptive ultrasonic aerosol generation system according to claim 1, characterized in that, The online refractive index detection module includes a light-emitting element, a flow cell, and a photoelectric receiving array arranged sequentially along the optical path. The light-emitting element has a light source wavelength of 880 nanometers. The flow cell is connected in series in the liquid supply pipeline for the liquid medium to flow through. The photoelectric receiving array is used to receive the light after it has been refracted by the liquid medium in the flow cell and output an electrical signal corresponding to the refractive index. The online refractive index detection module has a detection accuracy of ±0.002 and a response time of less than 1 second.

3. The multi-media adaptive ultrasonic aerosol generation system according to claim 1, characterized in that, The evacuation operation performed by the media switching cleaning sequence module is as follows: closing the inlet valve of the liquid supply line and driving the piezoelectric transducer at maximum power to discharge the residual liquid medium in the cavity; the high-frequency oscillation operation is as follows: after the evacuation operation is completed, controlling the adaptive transducer drive module to excite the piezoelectric transducer to oscillate with a high-frequency pulse higher than the standard operating frequency of the piezoelectric transducer, the frequency of the high-frequency pulse being 105% to 110% of the standard operating frequency, and the excitation duration being 3 to 10 seconds; the refractive index confirmation operation is as follows: after the high-frequency oscillation operation is completed, controlling the liquid supply line to inject new medium into the atomizing cavity module, and confirming the switching is complete after the refractive index reading of the online refractive index detection module stabilizes.

4. The multi-media adaptive ultrasonic aerosol generation system according to claim 1, characterized in that, The correction coefficient of the concentration sensor satisfies a quadratic polynomial fitting relationship with the refractive index of the liquid medium: ; in, This is the correction factor for the concentration sensor; The refractive index of the liquid medium; , , These are calibration coefficients, determined through factory calibration tests.

5. The multi-media adaptive ultrasonic aerosol generation system according to claim 1, characterized in that, The medium configuration package also includes the viscosity, density, and surface tension of the liquid medium; the system also includes a particle size estimation module, which is connected to both the medium identification and parameter mapping module and the adaptive transducer driving module; the particle size estimation module is used for: The system receives the viscosity, density, surface tension, transducer driving voltage, and power modulation depth output by the medium identification and parameter mapping module, and receives the resonant frequency of the piezoelectric transducer. Based on the received viscosity, density, surface tension, transducer driving voltage, power modulation depth, and resonant frequency, the system estimates the particle size of the current liquid medium after atomization. Based on the particle size of the current liquid medium after atomization and the obtained target particle size, the power modulation depth correction amount is calculated, and the power modulation depth is updated using the power modulation depth correction amount and then output to the adaptive transducer drive module. After re-driving the piezoelectric transducer using the updated power modulation depth, return to step "estimate the particle size of the current liquid medium after atomization based on the received viscosity, density, surface tension, transducer driving voltage, power modulation depth and resonant frequency, and repeat the iteration until the deviation between the particle size of the current liquid medium after atomization and the target particle size converges to a preset range".

6. The multi-media adaptive ultrasonic aerosol generation system according to claim 5, characterized in that, The particle size is calculated as follows: ； in, The particle size after atomization; The wavelength of the atomized surface droplets; This is the particle size control coefficient; Surface tension; Density; The electromechanical coupling coefficient of the piezoelectric transducer; This is the transducer drive voltage; Power modulation depth; is the resonant frequency of the piezoelectric transducer.

7. The multi-media adaptive ultrasonic aerosol generation system according to claim 5, characterized in that, The calculation method for the power modulation depth correction is as follows: ； in, This is the feedforward gain coefficient; This refers to the particle size after the current medium is atomized; Target particle size; The reference power modulation depth in the current media configuration package.

8. The multi-media adaptive ultrasonic aerosol generation system according to claim 5, characterized in that, The update method for the power modulation depth is as follows: ； in, The updated power modulation depth; This is the lower limit of the power modulation depth; This represents the upper limit of the power modulation depth. Indicates will Constraints to Within the range.

9. The multi-media adaptive ultrasonic aerosol generation system according to claim 1, characterized in that, The system communicates with an external testing system via a bus communication protocol. It receives media switching instructions and target concentration values ​​from the external testing system and reports system status, concentration data, and alarm information to the external testing system. The media switching cleaning sequence module triggers the cleaning sequence upon receiving the media switching instruction and sends a ready signal to the external testing system after the cleaning sequence is completed.

10. A multi-media adaptive ultrasonic aerosol generation control method, characterized in that, The control method includes: The refractive index of the liquid medium flowing through the liquid supply pipeline is detected in real time using an online refractive index detection module installed on the liquid supply pipeline, and a refractive index signal is output. The medium identification and parameter mapping module acquires the refractive index signal, matches the refractive index signal with the pre-stored correspondence between the refractive index ranges of various standard liquid media and the medium configuration package, and outputs the medium configuration package corresponding to the current liquid media; the medium configuration package includes at least the transducer drive voltage, frequency bias, power modulation depth and concentration sensor correction coefficient, refractive index, and particle size control coefficient. The adaptive transducer drive module receives the transducer drive voltage, the frequency bias, and the power modulation depth, constrains the resonant frequency search range with the frequency bias, and drives the piezoelectric transducer at the bottom of the atomizing cavity module to work with the transducer drive voltage and the power modulation depth, so as to atomize the liquid medium in the atomizing cavity module. The concentration adaptive closed-loop control module acquires the original concentration signal output by the light scattering concentration sensor located downstream of the mist outlet, acquires the concentration sensor correction coefficient from the medium identification and parameter mapping module, and acquires the target concentration value input externally. The original concentration signal is corrected using the concentration sensor correction coefficient to obtain the corrected concentration value. An adjustment signal is generated based on the comparison result between the corrected concentration value and the target concentration value. The adjustment signal is output to the adaptive transducer drive module to adjust the drive power or liquid supply rate of the piezoelectric transducer. The medium switching cleaning sequence module monitors the change in the refractive index signal. When the change exceeds a preset threshold, a cleaning sequence is triggered to perform aerosol generation for the new liquid medium. The cleaning sequence includes at least a purging operation, a high-frequency oscillation operation, and a refractive index confirmation operation.

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