A directional strong sound dispersing system with ranging function and a strong sound dispersing method

Abstract

The application discloses a directional strong sound dispersing system with a ranging function and a strong sound dispersing method, and relates to the technical field of strong sound dispersing.The application comprises a power module, a control module, a ranging module, a signal generating module, a signal conditioning module, a power amplification module and a transducer module connected with the power amplification module.The application has the beneficial effects that the ranging module can be used to measure the distance between the target and the system;the emission power can be controlled according to the distance and the sound pressure level that the target can bear, so that the target can be effectively driven away without being damaged.The emission transducer module is single, the strong directivity ultrasonic transducer adopts a mode of exciting a thin circular plate in a ring shape by a longitudinal vibration transducer, so that the strong directivity of the sound wave can be realized and the sound pressure level can be improved.

Description

Technical Field

[0001] This invention relates to the field of high-intensity sound dispersion technology, and in particular to a directional high-intensity sound dispersion system and method with ranging function. Background Technology

[0002] Currently, ultrasonic transducers are commonly used for dispersing birds or other animals in special situations. In ultrasonic transducers, frequency is generally inversely proportional to beamwidth; that is, the higher the frequency, the narrower the beamwidth (i.e., the degree of focusing of the sound wave). This is because high-frequency sound waves have shorter wavelengths, allowing energy to be concentrated in a smaller area, thus producing a narrower beam.

[0003] While higher frequencies offer narrower beamwidths, improving the directivity of sound waves, they are also more susceptible to absorption and scattering by the medium during propagation, leading to increased energy loss and shorter propagation distance. Furthermore, the penetrating power of high-frequency sound waves may be reduced, limiting their effectiveness in certain applications. Conversely, lower-frequency sound waves have wider beamwidths, allowing them to propagate over a wider area and providing greater coverage. However, their poor directivity may prevent precise concentration of sound energy on specific target areas.

[0004] High-intensity sound equipment is a highly efficient sound wave emitting device that uses high sound pressure level audio signals to propagate high-intensity sound waves. It effectively drives away targets through high-intensity noise stimulation. A high-power loudspeaker is mounted on a tripod to disperse targets within range. However, because the sound source size cannot be much smaller than the wavelength, it lacks good directivity, resulting in scattered sound waves, low efficiency, and a short effective range.

[0005] [CN 115938337 A] By setting multiple spaced ultrasonic transducer subarrays and having adjacent ultrasonic transducer subarrays emit ultrasonic waves of different frequency bands, audible sound can only be generated at the intersection of the beams of two adjacent ultrasonic transducer subarrays. This reduces the audible range of the ultrasonic transducer, achieves high audible sound directivity, and simultaneously shortens the propagation distance, thus improving the privacy when using this ultrasonic transducer array. Compared to Reference Invention Case 1, this invention improves the system's directivity, but due to the significant attenuation of high-frequency sound in air, it cannot propagate over long distances.

[0006] [CN202320057289.5] By using a transducer array with a matching circuit, the highly directional ultrasonic beam generated by the transducer array is combined with a modulated signal with an audio signal to achieve long-distance propagation of sound waves. However, since this invention does not consider the actual distance and the required power, it may harm flocks of birds. Secondly, the array method increases the cost of the system and the complexity of the circuit, and the assembly is also more complicated.

[0007] In summary, existing inventions do not include ranging capabilities, making it impossible to provide the required sound intensity for a specific distance, which may harm the target. Furthermore, since frequency and beamwidth are generally difficult to balance, they cannot propagate over long distances or in a directional manner. Summary of the Invention

[0008] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0009] In view of the problems existing in the prior art, the present invention is proposed.

[0010] Therefore, the technical problem to be solved by the present invention is how to combine ranging function with ensuring that long distance is not affected.

[0011] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a directional high-intensity sound dispersion system with ranging function, comprising:

[0012] The signal generation module generates and transmits pulse signals and receives reflected pulse echo signals in ranging mode for ranging; in dispersal mode, it generates a continuous wave for dispersal and modulates the sampled digital audio signal into a digital SPWM signal; the signal conditioning module conditions the pulse echo signal to the input range of signal sampling in ranging mode, converting it into a digital pulse signal; in dispersal mode, it controls the amplitude of the input audio signal, similarly conditioning it to the input range of signal sampling and converting it into a digital audio signal; the power amplification module amplifies the pulse signal in ranging mode; In the dispersal mode, the digital SPWM signal from the signal generation module is amplified and transmitted to the highly directional ultrasonic transducer of the transducer module, which emits ultrasonic waves directed at the dispersal target. The transducer module also includes a receiving transducer for receiving pulse echo signals reflected from the dispersal target in the ranging mode. The ranging module records the time of the transmitted pulse signal from the signal generation module and the time of the received pulse echo signal from the receiving transducer. The control module controls the system to operate in the ranging mode or the dispersal mode and receives power signals from the ranging module.

[0013] As a preferred embodiment of the directional high-intensity acoustic dispersion system with ranging function described in this invention, the highly directional ultrasonic transducer includes a longitudinally vibrating sandwich transducer, a stepped hollow amplitude transformer, and a fixed boundary thin circular plate. The longitudinally vibrating sandwich transducer is connected to the non-hollow end of the stepped hollow amplitude transformer, and the hollow end of the stepped hollow amplitude transformer is connected to the fixed boundary thin circular plate.

[0014] As a preferred embodiment of the directional high-intensity sound dispersal system with ranging function described in this invention, the signal generation module includes an FPGA signal generation and processing circuit; the FPGA signal generation and processing circuit generates and transmits pulse signals in ranging mode, giving the ranging chip a start signal, and gives the ranging chip an end signal after receiving the pulse echo signal; in dispersal mode, it generates a continuous wave for dispersal, modulates the sampled digital audio signal with a sine wave, and then compares it with the digital triangular wave signal generated inside the FPGA signal generation and processing circuit to generate a digital SPWM signal.

[0015] As a preferred embodiment of the directional high-intensity sound dispersion system with ranging function described in this invention, the signal conditioning module includes a first operational amplifier, a second operational amplifier, a third operational amplifier, and an ADC sampling circuit. The audio signal originates from a microphone signal or a computer audio signal. The first operational amplifier is used to differentially amplify the audio signal to suppress common-mode interference. The second and third operational amplifiers both adopt an inverse proportional operational structure, and the amplitude of the signal is controlled by adjusting a variable resistor. The ADC sampling circuit is used to sample the modulated analog signal and convert the analog signal into a digital signal.

[0016] As a preferred embodiment of the directional high-intensity acoustic dispersion system with ranging function described in this invention, the power amplification module includes a gate drive circuit and an H-bridge power amplification circuit. The gate drive circuit drives and amplifies the generated digital SPWM signal. The H-bridge power amplification circuit includes a first MOSFET, a second MOSFET, a third MOSFET, and a fourth MOSFET. The drains of the first and second MOSFETs are connected to the power supply VCC. The source of the first MOSFET is connected to the drain of the third MOSFET. The sources of the third and fourth MOSFETs are connected. The source of the second MOSFET is connected to the drain of the fourth MOSFET. A Vt+ circuit is led out between the first and third MOSFETs, and a Vt- circuit is led out between the second and fourth MOSFETs, which are respectively connected to the two ends of the highly directional ultrasonic transducer. The FPGA signal generation and processing circuit generates four drive signals, which are respectively connected to the drive amplification signals generated by the gate drive circuits of the first, second, third, and fourth MOSFETs.

[0017] As a preferred embodiment of the directional high-intensity acoustic dispersion system with ranging function described in this invention, the ranging module includes an SPI communication circuit, a clock crystal oscillator circuit, and a power supply circuit; the START and STOP ports of the ranging module are used to receive pulse signals indicating the start and end of the measurement time interval and to record the start time t1 and end time t2; the NTN port is the interrupt signal of the TDC, which is active low and connected to the FPGA, providing a flag for reading the timing result after the timing ends; the RSTN port is the reset signal of the TDC-GP22, active low and connected to the FPGA; the SSN, SCK, SI, and SO four-wire ports of the SPI communication circuit are connected to the SPI communication interface of the FPGA signal generation and processing circuit; the clock crystal oscillator circuit includes a 4MHz crystal oscillator circuit and a 32KHz crystal oscillator circuit.

[0018] As a preferred embodiment of the directional high-intensity sound dispersion system with ranging function described in this invention, it further includes a power supply module, which provides power supply voltage to the first operational amplifier, the second operational amplifier, and the third operational amplifier of the signal conditioning module, the ranging module, and the signal generation module.

[0019] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a strong sound dispersal method, using the above-mentioned directional strong sound dispersal system with ranging function, including the following steps: the control module switches to ranging mode, the control signal generation module generates and transmits a pulse signal; the signal generation module transmits the pulse signal to the signal conditioning module and transmits it to the START pin of the time measurement module of the ranging module, recording the start time t1; the receiving transducer receives the pulse echo signal of the dispersal target and transmits it to the STOP pin of the time measurement module of the ranging module, recording the end time t2; the distance S between the rangefinder and the dispersal target and the sound pressure level intensity Lp that the dispersal target can withstand are calculated to determine the sound power W of the strong directional ultrasonic transducer; the electrical power P of the strong directional ultrasonic transducer is determined according to the conversion relationship between the sound power W and the electrical power P of the strong directional ultrasonic transducer; the control module switches to dispersal mode, the control signal generation module generates an amplitude modulation wave signal, which is amplified by the power amplification module and applied to the strong directional ultrasonic transducer to generate a modulated sound wave and transmit it to the dispersal target for continuous dispersal.

[0020] In a preferred embodiment of the strong sound dispersal method of the present invention, the time measurement module calculates the time interval between t1 and t2. The signal is read by the FPGA signal generation and processing circuit. Then through the formula Obtain the distance S between the rangefinder and the target to be dispersed;

[0021] Based on the sound pressure level Lp1 that the target can withstand, calculate the sound pressure that the target can withstand. Sound pressure level Lp1 and sound pressure The following relationship exists:

[0022] ;

[0023] In the formula, To dissipate the sound pressure exerted on the target, The reference sound pressure for the medium; in air, the reference sound pressure... Values ​​taken from national standards ;

[0024] Assuming the radiated sound wave propagates along the x-direction, then the distance from the dispersing system... The sound pressure at that location is:

[0025] ;

[0026] in, To dissipate the sound pressure emitted by the system, The attenuation coefficient in the propagation medium;

[0027] Attenuation coefficient With sound wave frequency The relationship is:

[0028] ;

[0029] in, Let be the constant of the sound transmission medium, under normal temperature and pressure. The value is ;

[0030] According to distance The attenuation relationship allows us to derive the sound pressure level (SPL) to be emitted by the highly directional ultrasonic transducer in the dispersal system, where: ;

[0031] The sound intensity level to be emitted by a highly directional ultrasonic transducer can be expressed as:

[0032] ;

[0033] in, For sound intensity, The reference sound intensity for the medium; in air, the reference sound intensity... Values ​​taken from national standards ;

[0034] Combining the above relationships, we can obtain:

[0035] ;

[0036] Among them, due to the characteristic impedance of air, The value is close to ;

[0037] The expression for sound intensity I is:

[0038] ;

[0039] Known sound intensity The acoustic power W of the dispersing system can then be calculated, expressed as:

[0040] ;

[0041] In the formula The radiation area of ​​the dispersion system;

[0042] The electrical power of the dispersing system It can be represented as:

[0043] ;

[0044] In the formula, For the applied voltage, The resistance value;

[0045] The acoustic power W and the electrical power P have the following relationship:

[0046] ;

[0047] In the formula, Electroacoustic efficiency is typically taken as 50%.

[0048] In a preferred embodiment of the strong sound dispersal method of the present invention, the radiation directivity of the transducer module can be calculated by the following formula:

[0049] ;

[0050] Among them, for spatial observation points located in the xz plane The distance between the origin and the origin is Divide the outer ring of the circular plate into an infinite number of small facets, each of which can be considered a point source. Then, according to the principle of superposition of point sources, each of the infinitesimal elements on the outer ring surface... The sound pressure at a point can be expressed as:

[0051] ;

[0052] In the formula, Angular frequency, For the thickness of the plate, It is the radius. For wave number, , Let be the transverse velocity amplitudes of the inner and outer rings of the annular excitation, respectively, and their expressions are as follows:

[0053] ;

[0054] ;

[0055] ;

[0056] In the formula, Angular frequency, The density of the plate, For the bending vibration stiffness of the plate, It is Young's modulus. For the thickness of the plate, Poisson's ratio, , These are the first and second kind of zero-order Bessel functions, respectively. , These are the first and second kind zero-order modified Bessel functions, respectively. , , , The nonlinear coefficient can be given by the boundary conditions and continuity conditions of the thin plate. The boundary conditions of the thin plate are zero displacement and zero displacement derivative. The continuity conditions at the excitation position are continuous displacement and continuous transverse shear force.

[0057] The beneficial effects of this invention are:

[0058] This invention enables long-distance directional transmission of audio signals by combining a generated signal with dispersive information with a highly directional ultrasonic transducer. The transmitting transducer module is a single unit; this highly directional ultrasonic transducer employs a method of longitudinally vibrating transducer annularly exciting a thin circular plate, achieving both strong directivity of the sound wave and increased sound pressure level. The highly directional ultrasonic transducer of this invention is a longitudinal bending mode conversion transducer, possessing the high electroacoustic efficiency of a longitudinal sandwich transducer and the low radiation impedance of a bending vibrating thin plate, making it more suitable for airborne propagation. Combined with a ranging module, the distance between the target and the system can be measured. The transmission power can be controlled according to the distance and the sound pressure level the target can withstand, achieving effective dispersal without damaging the target. Attached Figure Description

[0059] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0060] Figure 1 This is a system block diagram of the present invention;

[0061] Figure 2 The power module of this invention;

[0062] Figure 3 This is the signal generation module of the present invention;

[0063] Figure 4 This is the signal conditioning module of the present invention;

[0064] Figure 5 This is the power amplifier module of the present invention;

[0065] Figure 6 This is the ranging module of the present invention;

[0066] Figure 7This is a cross-sectional view of the highly directional ultrasonic transducer of Embodiment 5 of the present invention;

[0067] Figure 8 This is a schematic diagram of the bending vibration radiation circular plate and the hollow stepped amplitude transformer of Embodiment 5 of the present invention;

[0068] Figure 9 The modal diagram of the hollow stepped amplitude transformer and the fixed boundary circular plate in Embodiment 5 of the present invention is shown.

[0069] Figure 10 This is a modal diagram of the highly directive ultrasonic transducer of Embodiment 5 of the present invention;

[0070] Figure 11 This is a directivity diagram of the highly directive ultrasonic transducer in Embodiment 5 of the present invention;

[0071] Figure 12 This is a schematic diagram of the highly directional ultrasonic transducer of Embodiment 7 of the present invention;

[0072] Figure 13 This is a schematic diagram of the bending vibration radiation circular plate and the hollow stepped amplitude transformer of Embodiment 7 of the present invention;

[0073] Figure 14 The modal diagram of the hollow stepped amplitude transformer and the fixed boundary circular plate is shown in Specific Implementation Example 7 of the present invention.

[0074] Figure 15 The modal diagram of the highly directive ultrasonic transducer in specific embodiment 7 of the present invention is shown below.

[0075] Figure 16 This is a directional diagram of the highly directional ultrasonic transducer, which is a specific embodiment of the present invention, Example 7. Detailed Implementation

[0076] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0077] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0078] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0079] Example 1

[0080] Reference Figure 1-4 This is the first embodiment of the present invention, which provides a directional high-intensity sound dispersion system with ranging function, comprising:

[0081] The signal generation module 100 generates and transmits pulse signals and receives reflected pulse echo signals for ranging mode; in dispersal mode, it generates a continuous wave for dispersal and modulates the sampled digital audio signal into a digital SPWM signal. The signal conditioning module 200 conditions the pulse echo signal to the input range of signal sampling in ranging mode, converting it into a digital pulse signal; in dispersal mode, it controls the amplitude of the input audio signal, similarly conditioning it to the input range of signal sampling and converting it into a digital audio signal. The power amplification module 300 amplifies the pulse signal in ranging mode and amplifies the signal from the source in dispersal mode. The signal generation module sends a digital SPWM signal to the transducer module's highly directional ultrasonic transducer 401, which emits ultrasonic waves to disperse the target. The transducer module 400 also includes a receiving transducer 402, which receives the pulse echo signal reflected by the dispersed target in ranging mode. The ranging module 500 records the time of the transmitted pulse signal from the signal generation module and the time of the received pulse echo signal from the receiving transducer. The control module 600 controls the system to operate in ranging mode (generating pulse waves) or dispersing mode (generating continuous waves) and receives power signals from the ranging module.

[0082] It also includes a power supply module 700, which provides power supply voltage to the first operational amplifier, the second operational amplifier, and the third operational amplifier of the signal conditioning module, the ranging module, and the signal generation module.

[0083] The control module is used for mode selection and automatic switching; the signal generation module generates the signals required for both modes and modulates the input audio signal and carrier signal to generate a modulated signal; the signal conditioning module controls the amplitude of the received echo and the input audio signal, conditioning them to a reasonable sampling range; the power amplification module amplifies the signal waveforms in both modes; the ranging module measures the distance between the system and the target, assesses the actual power required for effective dispersal, and feeds it back to the control module to ensure the system operates continuously at that power; the transducer module assesses the distance to the target and increases the transmission distance of the dispersal signal.

[0084] The power module 700 consists of integrated circuits U3, U4, U11, U12, U20, U21, U22, and connector H8. Integrated circuits U3, U4, and U11 are model B2415S-1WR3; integrated circuit U12 is model TLV75733PDBVR; integrated circuit U20 is B2415S-1WR3; integrated circuit U21 is G2405S-2W; integrated circuit U22 is B2405S-1WR3_C5150989; and connector H8 is a 2-pin connector.

[0085] The signal generation module 100 includes an FPGA signal generation and processing circuit; the audio signal comes from a microphone signal or a computer audio signal; the FPGA signal generation and processing circuit generates and transmits a pulse signal in the ranging mode to give the ranging chip a start signal, and gives the ranging chip an end signal after receiving the pulse echo signal; in the dispersal mode, it generates a continuous wave for dispersal, modulates the sampled digital audio signal with a sine wave, and then compares it with the digital triangular wave signal generated inside the FPGA signal generation and processing circuit to generate a digital SPWM signal.

[0086] The FPGA in the signal generation module of this invention is model EP4CE6E22C8.

[0087] The signal conditioning module includes a first operational amplifier, a second operational amplifier, a third operational amplifier, and an ADC sampling circuit. The first operational amplifier is used to differentially amplify the audio signal to suppress common-mode interference. The second and third operational amplifiers both adopt an inverse proportional operational structure and control the amplitude of the signal by adjusting a variable resistor. The ADC sampling circuit is used to sample the modulated analog signal and convert the analog signal into a digital signal.

[0088] The signal conditioning module of this invention consists of integrated circuits U8, U9, U10, U13, U19A, U19B, U16, U17, U18, and plug-in RF1. The integrated circuits are model U8TPL0102-100PWR, U9 is model OPA657U, U10 is model AD8065ART-R2, U13 is model AD9280ARS, U19A and U19B are model TL072IDR, U16 is model AD8130ARZ-REEL, U17 and U18 are model OPA657U, and plug-in RF1 is model BWSMA-KE-Z001_C496549.

[0089] Example 2

[0090] Reference Figure 5 This is the second embodiment of the present invention, which differs from the previous embodiment in that: this embodiment provides a power amplification module, which includes an H-bridge power amplification circuit, comprising a first MOSFET, a second MOSFET, a third MOSFET, and a fourth MOSFET; the drains of the first and second MOSFETs are connected to the power supply VCC, the source of the first MOSFET is connected to the drain of the third MOSFET, and the two sources of the third and fourth MOSFETs are connected; the source of the second MOSFET is connected to the drain of the fourth MOSFET; Vt+ is led out between the first and third MOSFETs, and Vt- is led out between the second and fourth MOSFETs, respectively connected to the two ends of a highly directional ultrasonic transducer; an FPGA signal generation and processing circuit generates four drive signals, which are respectively connected to the drive amplification signals generated by the gate drive circuits of the first, second, third, and fourth MOSFETs.

[0091] Example 3

[0092] Reference Figure 6 This is the third embodiment of the present invention, which differs from the previous two embodiments in that: this embodiment provides a ranging module, including an SPI communication circuit, a clock crystal circuit of 4MHz and 32.768KHz, and a power supply circuit.

[0093] The START and STOP ports of the ranging module are used to receive pulse signals indicating the start and end of the measurement time interval and record the start time t1 and end time t2, i.e., Start(t1) and End(t2). NTN is the interrupt signal of TDC, which is active low and connected to the FPGA, providing a flag for reading the timing result after the timing ends. RSTN is the reset signal of TDC-GP22, which is active low and connected to the FPGA. SSN, SCK, SI, and SO are four-wire ports connected to the SPI communication interface of the FPGA signal generation and processing circuit, realizing communication between the FPGA controller and TDC-GP22, and controlling the read and write of the registers of TDC-GP22 to complete the time measurement function.

[0094] A 4MHz high-speed clock unit is provided for calibration of the TDC-GP22. Within its measurement range, the TDC-GP22 also requires a high-speed clock signal as part of its time measurement unit. A 32.768kHz reference clock is used to control the high-speed clock startup and for clock calibration. A TLV75733PDBVR is used to provide a 3.3V power supply to the system.

[0095] Example 4

[0096] Reference Figure 1 This is the fourth embodiment of the present invention, which differs from the previous three embodiments in that: this embodiment provides a strong acoustic dispersion method, characterized in that: the control module switches to ranging mode, the control signal generation module generates and transmits a pulse signal; the signal generation module transmits the pulse signal to the signal conditioning module, and transmits it to the START pin of the time measurement module of the ranging module, recording the start time t1; the driven amplifies the transmitted pulse signal waveform transmitted to the signal conditioning module, and acts on the strongly directional ultrasonic transducer through the power amplification module to generate ultrasonic waves that are transmitted to the dispersion target; the receiving transducer receives the pulse echo signal from the dispersion target. The time measurement module's STOP pin is transmitted to the ranging module, and the end time t2 is recorded. The distance S between the rangefinder and the target to be dispersed and the sound pressure level Lp that the target can withstand are calculated. Based on the sound wave attenuation law, the sound pressure level SPL required by the highly directional ultrasonic transducer is determined. The radiated sound power of the highly directional ultrasonic transducer is calculated, and the electrical power P of the highly directional ultrasonic transducer is determined by combining the conversion relationship between electrical power and sound power. The control module switches to the dispersal mode, the control signal generation module generates an amplitude modulation wave signal, and the highly directional ultrasonic transducer emits modulated sound waves towards the target to continuously disperse it.

[0097] Using a directional high-intensity acoustic dispersion system with ranging function, firstly, the inner and outer radii of the hollow circular tube section are determined based on the size of the sandwich transducer at the estimated operating frequency. Then, its longitudinal length is determined based on the calculation formula of the hollow stepped amplitude transformer. Finally, the radius and thickness of the annular excitation fixed boundary thin circular plate are determined based on finite element simulation. The displacement distribution on the surface of the thin circular plate is obtained through theoretical calculation, so that the frequency of the whole composed of the hollow stepped amplitude transformer and the annular excitation fixed boundary thin circular plate is consistent with the frequency of the longitudinal sandwich transducer.

[0098] The system operates in two modes, automatically switched by the control module. In the distance measurement mode, the FPGA processor sends digital pulse signals to both the measurement and signal conditioning modules: the START pin of the time measurement module serves as the timing start signal for the TDC-GP22; the signal conditioning module amplifies this pulse signal and, after passing it through a power amplifier, applies it to a highly directional ultrasonic transducer. The transducer emits a pulse wave, and the reflected echo pulse acts on a receiving transducer next to the highly directional ultrasonic transducer. The echo pulse is then conditioned to obtain a digital signal, which is transmitted to the STOP pin of the time measurement module, serving as the timing end signal for the TDC-GP22; the TDC-GP22 time measurement module calculates the time interval between t1 and t2. Read by FPGA Then through the formula Obtain the distance S between the rangefinder and the target being measured;

[0099] Based on the sound pressure level Lp1 that the target can withstand, calculate the sound pressure that the target can withstand. Sound pressure level Lp1 and sound pressure The following relationship exists:

[0100] ;

[0101] In the formula, To dissipate the sound pressure exerted on the target, The reference sound pressure for the medium; in air, the reference sound pressure... Values ​​taken from national standards ;

[0102] Because the amplitude of ultrasound decreases exponentially with increasing propagation distance during propagation, assuming the radiated sound wave propagates along the x-direction, the distance from the dispersing system... The sound pressure at that location is:

[0103] ;

[0104] in, To dissipate the sound pressure emitted by the system, The attenuation coefficient in the propagation medium;

[0105] Attenuation coefficient With sound wave frequency The relationship is:

[0106] ;

[0107] in, Let be the constant of the sound transmission medium, under normal temperature and pressure. The value is ;

[0108] According to distance The attenuation relationship allows us to derive the sound pressure level (SPL) to be emitted by the highly directional ultrasonic transducer in the dispersal system, where: ;

[0109] The sound intensity level to be emitted by a highly directional ultrasonic transducer can be expressed as:

[0110] ;

[0111] in, For sound intensity, The reference sound intensity for the medium; in air, the reference sound intensity... Values ​​taken from national standards ;

[0112] Combining the above relationships, we can obtain:

[0113] ;

[0114] Among them, due to the characteristic impedance of air, The value is close to , Since the value of is approximately 0, the sound pressure level SPL and the sound intensity level SIL are approximately equal in value.

[0115] The expression for sound intensity I is:

[0116] ;

[0117] Known sound intensity The acoustic power W of the dispersing system can then be calculated, expressed as:

[0118] ;

[0119] In the formula, The radiation area of ​​the dispersion system;

[0120] The electrical power of the dispersing system It can be represented as:

[0121] ;

[0122] In the formula, For the applied voltage, The resistance value;

[0123] The acoustic power W and the electrical power P have the following relationship:

[0124] ;

[0125] In the formula, Electroacoustic efficiency is typically taken as 50%.

[0126] The radiation directivity of the transducer module can be calculated using the following formula:

[0127] ;

[0128] Among them, for spatial observation points located in the xz plane The distance between the origin and the origin is The outer ring of the circular plate is divided into an infinite number of small facets, and each small facet is regarded as a point source.

[0129] According to the principle of superposition of point sources, each infinitesimal element on the outer surface... The sound pressure at a point can be expressed as:

[0130] ;

[0131] In the formula, Angular frequency, For the thickness of the plate, It is the radius. For wave number, , Let be the transverse velocity amplitudes of the inner and outer rings of the annular excitation, respectively, and their expressions are as follows:

[0132] ;

[0133] ;

[0134] ;

[0135] In the formula, Angular frequency, The density of the plate, For the bending vibration stiffness of the plate, It is Young's modulus. For the thickness of the plate, Poisson's ratio, , These are the first and second kind of zero-order Bessel functions, respectively. , These are the first and second kind zero-order modified Bessel functions, respectively. , , , The nonlinear coefficient can be given by the boundary conditions and continuity conditions of the thin plate. The boundary conditions of the thin plate are zero displacement and zero displacement derivative. The continuity conditions at the excitation position are continuous displacement and continuous transverse shear force.

[0136] The highly directional ultrasonic transducers in the transducer module can also be arranged in an array.

[0137] Example 5

[0138] Reference Figure 7-11 This is the fifth embodiment of the present invention, which differs from the previous four embodiments in that: this embodiment provides a highly directional ultrasonic transducer 401, including a longitudinal sandwich ultrasonic transducer 401a, a hollow stepped amplitude transformer 401b, and a fixed boundary thin circular plate 401c, wherein the boundary of the fixed boundary thin circular plate is fixed, and the longitudinal sandwich transducer and the hollow stepped amplitude transformer, and the hollow stepped amplitude transformer and the fixed boundary thin circular plate are respectively tightly connected by bolts.

[0139] In a further embodiment, the longitudinal sandwich transducer is designed with a frequency of 30kHz. The front cover is made of 7075 aviation aluminum with a radius of 25mm and a length of 26mm. There are two piezoelectric ceramic rings made of PZT-8 material with an outer diameter of 25mm, an inner diameter of 8.5mm, and a thickness of 6.5mm. The two piezoelectric ceramic rings have opposite polarization directions. One side of the piezoelectric ceramic ring is connected to the positive lead, and the other side is connected to the negative lead. The input voltage is 1V. The rear cover is made of 45# steel with a radius of 25mm and a length of 45mm. The resonant frequency of the longitudinal sandwich transducer is approximately 30kHz.

[0140] Reference Figure 8 , 9 The hollow stepped amplitude transformer and the fixed-boundary thin circular plate are designed for a frequency of 30 kHz, and are made of 45# steel. The hollow stepped amplitude transformer has an outer diameter of 25 mm, an inner diameter of 20 mm, a hollow section length of 57 mm, and a solid section length of 57 mm. The fixed-boundary bending vibration radiation circular plate has a radius R of 50 mm and a thickness h of 5 mm. The characteristic frequency of the hollow stepped amplitude transformer and the fixed-boundary bending vibration circular plate is 30 kHz.

[0141] The implementation of the above-mentioned highly directional ultrasonic transducer includes the following steps: under the excitation of an external voltage signal, it performs a composite vibration of longitudinal vibration and bending vibration, and radiates sound wave energy outward. By adjusting the size of the hollow stepped amplitude transformer and the bending vibration disc with fixed boundary, the frequency after coupling is made the same as the resonant frequency of the lower longitudinal sandwich transducer, so that the highly directional ultrasonic transducer formed by the overall combination can operate efficiently.

[0142] Reference Figure 10 The vibration mode of the highly directional ultrasonic transducer is as follows: the longitudinal sandwich transducer and the hollow stepped amplitude transformer vibrate longitudinally, the circular plate vibrates in a bending manner, and the vibration phases inside and outside the circular plate are the same. The overall resonant frequency of the narrow beam transducer is about 30kHz.

[0143] Reference Figure 11 To implement the radiation directivity of the transducer in Case 1 in air, the main lobe is sharp, the -3dB beamwidth is 6.2°, the side lobes are smaller than the main lobe, and the radiation direction is mainly along the transducer axis.

[0144] As can be seen from the above, the highly directional ultrasonic transducer of this embodiment can maintain an ideal low frequency and ensure a better beamwidth, that is, accurate directivity when dispersing at a long distance, thus solving the problem of the difficulty in balancing and compatibility between frequency and beamwidth in traditional ultrasonic transducers.

[0145] Example 6

[0146] This is the sixth embodiment of the present invention, which differs from the previous five embodiments in that it provides a strong sound dispersal method. The hollow stepped amplitude transformer and the fixed boundary stepped thin circular plate are made of metal, which can be adjusted according to the actual application scenario. They can be aluminum alloy, titanium alloy, steel, or other materials. However, the overall vibration frequency of the high-directivity ultrasonic transducer must be the same as the overall vibration frequency of the hollow stepped amplitude transformer and the fixed boundary stepped thin circular plate.

[0147] The design steps are as follows: First, estimate the required directivity intensity of the transducer, i.e., the beamwidth of the emitted ultrasonic waves, based on the transmission distance of the actual working scenario. Then, calculate the operating frequency of the transducer based on the beamwidth, and finally optimize the transducer's dimensions. Since the design technology of sandwich transducers is relatively mature, the main focus is on the integrated design of the hollow stepped amplitude transformer and the bending vibrating thin circular plate.

[0148] First, the inner and outer radii of the hollow circular tube section are determined based on the dimensions of the sandwich transducer. Then, its longitudinal length is determined according to the calculation formula of the hollow stepped amplitude transformer. Finally, the radius and thickness of the annular excitation fixed boundary thin circular plate are determined based on finite element simulation. The displacement distribution on the surface of the thin circular plate is obtained through finite element simulation. Then, steps are added to the corresponding anti-phase region according to the displacement distribution. The step height is half of the wavelength of the sound wave at this frequency, so that the phase of this part is consistent with that of other parts. This ensures that the overall frequency of the hollow stepped amplitude transformer and the annular excitation fixed boundary stepped thin circular plate is consistent with the frequency of the longitudinal sandwich transducer.

[0149] The frequency equation for the stepped hollow amplitude transformer is as follows:

[0150] ;

[0151] The radiation directivity of the transducer module can be calculated using the following formula:

[0152] ;

[0153] in:

[0154] ;

[0155] In the formula, Angular frequency, , These refer to the fixed-boundary stepped thin circular plate substrate and the thickness of the steps, respectively. It is the radius. For wave number, , , , Let be the transverse vibration amplitudes of each part of the fixed-boundary stepped thin circular plate, and their expressions are as follows:

[0156] ;

[0157] ;

[0158] ;

[0159] ;

[0160] ;

[0161] ;

[0162] In the formula, The density of the plate, For the bending vibration stiffness of the plate, It is Young's modulus. For the thickness of the plate, It is Poisson's ratio.

[0163] , These are the first and second kind of zero-order Bessel functions, respectively. , These are the first and second type zero-order modified Bessel functions, respectively. , , , The nonlinear coefficient can be given by the boundary conditions and continuity conditions of the thin plate. Here, the boundary conditions for the thin plate are zero displacement and zero displacement derivative. The continuity conditions at the excitation location are continuous displacement and continuous transverse shear force. Substituting the boundary conditions and continuity conditions into the above formula, the far-field directivity and the magnitude of the radiated sound pressure of the circular plate can be obtained.

[0164] The radiation directivity of a highly directional transducer can be calculated by combining the above relationships, where the directivity opening angle range is: .

[0165] Example 7

[0166] Reference Figure 12-16 This is the seventh embodiment of the present invention, which differs from the previous six embodiments in that: compared with the above-described embodiment 4, this embodiment is different in that, referring to... Figure 12 The present invention provides another type of highly directional ultrasonic transducer, comprising a longitudinal sandwich ultrasonic transducer, a hollow stepped amplitude transformer, and a fixed boundary stepped thin circular plate, wherein the outer boundary of the fixed boundary stepped thin circular plate is fixed, and the longitudinal sandwich transducer, the hollow stepped amplitude transformer, and the fixed boundary stepped thin circular plate are respectively tightly connected by bolts.

[0167] Reference Figure 12 , Figure 13The longitudinal sandwich transducer is designed for a frequency of approximately 30kHz. The front cover is made of 7075 aviation aluminum with a radius of 25mm and a length of 26mm. There are two piezoelectric ceramic rings made of PZT-8 material with an outer diameter of 25mm, an inner diameter of 8.5mm, and a thickness of 6.5mm. The two piezoelectric ceramic rings have opposite polarization directions. One side of the piezoelectric ceramic ring is connected to the positive lead, and the other side is connected to the negative lead. The input voltage is 1V. The rear cover is made of 45# steel with a radius of 25mm and a length of 45mm.

[0168] Reference Figure 14 The design frequency of the hollow stepped amplitude transformer coupled with the fixed boundary stepped thin circular plate is 30 kHz, and the material is 45# steel. The hollow stepped amplitude transformer has an outer diameter of 25 mm, an inner diameter of 20 mm, a hollow section length of 37 mm, and a solid section length of 37 mm. The base radius a4 of the fixed boundary stepped thin circular plate is 65 mm, and the thickness h1 is 5 mm. The inner radius a1 of the step is 15 mm, the outer radius a3 is 35 mm, and the total step height h2 is 10 mm. The frequency of the hollow stepped amplitude transformer coupled with the fixed boundary stepped thin circular plate is 30.151 kHz.

[0169] The implementation of the above-mentioned highly directional transducer includes the following steps: under the excitation of an external voltage signal, it undergoes a composite vibration of longitudinal and bending vibrations, and radiates sound wave energy axially toward the circular plate. By adjusting the size of the hollow stepped amplitude transformer and the fixed boundary stepped thin circular plate, the overall resonant frequency after coupling is the same as the resonant frequency of the lower longitudinal sandwich transducer, so that the highly directional ultrasonic transducer can operate efficiently at this frequency.

[0170] First, the inner and outer radii of the hollow circular tube section are determined based on the dimensions of the sandwich transducer. Then, its longitudinal length is determined according to the calculation formula of the hollow stepped amplitude transformer. Finally, the radius and thickness of the annular excitation fixed boundary thin circular plate are determined based on finite element simulation. The displacement distribution on the surface of the thin circular plate is obtained through finite element simulation. Then, steps are added to the corresponding anti-phase region according to the displacement distribution. The step height is half of the wavelength of the sound wave at this frequency, so that the phase of this part is consistent with that of other parts. This ensures that the overall frequency of the hollow stepped amplitude transformer and the annular excitation fixed boundary stepped thin circular plate is consistent with the frequency of the longitudinal sandwich transducer.

[0171] Reference Figure 15 The vibration mode of the highly directional ultrasonic transducer is as follows: the longitudinal sandwich transducer and the hollow stepped amplitude transformer vibrate longitudinally, the fixed boundary stepped thin circular plate vibrates in a bending manner, and the vibration phases inside and outside the circular plate are the same. The overall resonant frequency of the narrow beam transducer is 30.072kHz.

[0172] Reference Figure 16To implement the radiation directivity of the transducer in Case 1 in air, the main lobe is sharp, the -3dB beamwidth is 6.2°, the side lobes are smaller than the main lobe, and the radiation direction is mainly along the transducer axis.

[0173] As can be seen from the above, similarly, the highly directional ultrasonic transducer of this embodiment can maintain an ideal low frequency and ensure a better beamwidth, that is, accurate directivity when dispersing at a long distance, thus solving the problem of the difficulty in balancing and compatibility between frequency and beamwidth in traditional ultrasonic transducers.

[0174] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (such as variations in installation arrangement, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application. For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of the element may be inverted or otherwise changed, and the nature or number or position of the discrete elements may be altered or changed. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the invention is not limited to the particular embodiments but extends to a variety of modifications that still fall within the scope of the appended claims.

[0175] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments may be omitted.

[0176] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine task in design, manufacturing, and production without requiring extensive experimentation.

[0177] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A directional high-intensity acoustic dispersion system with ranging function, characterized in that: The signal generation module generates and transmits pulse signals in ranging mode and receives reflected pulse echo signals for ranging; in dispersal mode, it generates continuous waves for dispersal and modulates the sampled digital audio signal into a digital SPWM signal. In ranging mode, the signal conditioning module conditions the pulse echo signal to the input range of signal sampling and converts it into a digital pulse signal; in dispersal mode, it controls the amplitude of the input audio signal and similarly conditions it to the input range of signal sampling and converts it into a digital audio signal. A power amplification module is used to amplify the pulse signal in ranging mode; and to amplify the digital SPWM signal from the signal generation module in dispersal mode and transmit it to the highly directional ultrasonic transducer of the transducer module, which emits ultrasonic waves to disperse the target. The transducer module also includes a receiving transducer for receiving pulse echo signals reflected by a dispersed target in ranging mode. The ranging module is used to record the time of the transmitted pulse signal from the signal generation module and the time of the received pulse echo signal from the receiving transducer; The control module is used to control the system to operate in ranging mode or dispersal mode, and to receive power signals from the ranging module. The highly directional ultrasonic transducer includes a longitudinally vibrating sandwich transducer, a stepped hollow amplitude transformer, and a fixed boundary thin circular plate. The longitudinally vibrating sandwich transducer is connected to the non-hollow end of the stepped hollow amplitude transformer, and the hollow end of the stepped hollow amplitude transformer is connected to the fixed boundary thin circular plate. The signal generation module includes an FPGA signal generation and processing circuit. The audio signal originates from a microphone signal or a computer audio signal; The FPGA signal generation and processing circuit generates and transmits pulse signals in ranging mode to give the ranging chip a start signal and gives the ranging chip an end signal after receiving the pulse echo signal. In dispersal mode, it generates a continuous wave for dispersal and modulates the sampled digital audio signal with a sine wave, and then compares it with the digital triangular wave signal generated inside the FPGA signal generation and processing circuit to generate a digital SPWM signal. The signal conditioning module includes a first operational amplifier, a second operational amplifier, a third operational amplifier, and an ADC sampling circuit; The first operational amplifier is used to differentially amplify the audio signal to suppress common-mode interference; Both the second and third operational amplifiers employ an inverting proportional operational structure, and the amplitude of the signal is controlled by adjusting a variable resistor. The ADC sampling circuit is used to sample the modulated analog signal and convert the analog signal into a digital signal. The power amplification module includes a gate drive circuit and an H-bridge power amplification circuit, wherein the gate drive circuit drives and amplifies the generated digital SPWM signal. The H-bridge power amplifier circuit includes a first MOSFET, a second MOSFET, a third MOSFET, and a fourth MOSFET; The drains of the first MOSFET and the second MOSFET are connected to the power supply VCC. The source of the first MOSFET is connected to the drain of the third MOSFET. The two sources of the third MOSFET and the fourth MOSFET are connected. The source of the second MOSFET is connected to the drain of the fourth MOSFET; Vt+ is led out between the first MOS transistor and the third MOS transistor, and Vt- is led out between the second MOS transistor and the fourth MOS transistor, which are respectively connected to the two ends of the highly directional ultrasonic transducer; The FPGA signal generation and processing circuit generates four drive signals, which are respectively connected to the drive amplification signals generated by the gate drive circuits of the first MOS transistor, the second MOS transistor, the third MOS transistor, and the fourth MOS transistor. The ranging module includes an SPI communication circuit, a clock crystal circuit, and a power supply circuit; The START and STOP ports of the ranging module are used to receive pulse signals indicating the start and end of the measurement time interval and to record the start time t1 and end time t2; the NTN port is the interrupt signal of the TDC, which is active low and connected to the FPGA, providing a flag for reading the timing result after the timing ends; the RSTN port is the reset signal of the TDC-GP22, which is active low and connected to the FPGA. The four-wire ports SSN, SCK, SI, and SO of the SPI communication circuit are connected to the SPI communication interface of the FPGA signal generation and processing circuit. The clock crystal circuit includes a 4MHz crystal circuit and a 32KHz crystal circuit.

2. The directional high-intensity sound dispersion system with ranging function as described in claim 1, characterized in that: It also includes a power supply module, which provides power supply voltage to the first operational amplifier, the second operational amplifier, and the third operational amplifier of the signal conditioning module, the ranging module, and the signal generation module.

3. A method for dispersing loud noise, characterized in that: The method of using the directional high-intensity acoustic dispersion system with ranging function as described in claim 1 or 2 includes the following steps. When the control module switches to ranging mode, the control signal generation module generates and transmits pulse signals. The signal generation module transmits a pulse signal to the signal conditioning module and then to the START pin of the time measurement module of the ranging module to record the start time t1; The receiving transducer receives the pulse echo signal of the dispersed target and transmits it to the STOP pin of the time measurement module of the ranging module, and records the end time t2. Calculate the distance S between the rangefinder and the target to be dispersed and the sound pressure level Lp that the target to be dispersed can withstand, and determine the acoustic power W of the highly directional ultrasonic transducer; Based on the conversion relationship between the acoustic power W and the electrical power P of a highly directional ultrasonic transducer, the electrical power P of the highly directional ultrasonic transducer is determined; When the control module switches to the dispersal mode, the control signal generation module generates an amplitude modulation wave signal, which is then amplified by the power amplification module and applied to the highly directional ultrasonic transducer to generate a modulated sound wave and emit it to the dispersal target for continuous dispersal.

4. The method for dispersing loud noise as described in claim 3, characterized in that: The time measurement module calculates the time interval between t1 and t2. The signal is read by the FPGA signal generation and processing circuit. Then through the formula Obtain the distance S between the rangefinder and the target to be dispersed; Based on the sound pressure level Lp1 that the target can withstand, calculate the sound pressure that the target can withstand. Sound pressure level Lp1 and sound pressure The following relationship exists: ； In the formula, To dissipate the sound pressure exerted on the target, The reference sound pressure for the medium; in air, the reference sound pressure... Values ​​taken from national standards ; Assuming the radiated sound wave propagates along the x-direction, then the distance from the dispersing system... The sound pressure at that location is: ； in, To dissipate the sound pressure emitted by the system, The attenuation coefficient in the propagation medium; Attenuation coefficient With sound wave frequency The relationship is: ； in, Let be the constant of the sound transmission medium, under normal temperature and pressure. The value is ; According to distance The attenuation relationship allows us to derive the sound pressure level (SPL) to be emitted by the highly directional ultrasonic transducer in the dispersal system, where: ; The sound intensity level to be emitted by a highly directional ultrasonic transducer can be expressed as: ； in, For sound intensity, The reference sound intensity for the medium; in air, the reference sound intensity... Values ​​taken from national standards ; Combining the above relationships, we can obtain: ； Among them, due to the characteristic impedance of air, The value is close to ; The expression for sound intensity I is: ； Known sound intensity The acoustic power W of the dispersing system can then be calculated, expressed as: ； In the formula, The radiation area of ​​the dispersion system; The electrical power of the dispersing system It can be represented as: ； In the formula, For the applied voltage, The resistance value; The acoustic power W and the electrical power P have the following relationship: ； In the formula, Electroacoustic efficiency is typically taken as 50%.

5. The method for dispersing loud noise as described in claim 4, characterized in that: The radiation directivity of the transducer module can be calculated using the following formula: ； Among them, for spatial observation points located in the xz plane The distance between the origin and the origin is The outer ring of the circular plate is divided into an infinite number of small facets, and each small facet is regarded as a point source. According to the principle of superposition of point sources, each infinitesimal element on the outer surface... The sound pressure at a point can be expressed as: ； In the formula, Angular frequency, For the thickness of the plate, It is the radius. For wave number, , Let be the transverse velocity amplitudes of the inner and outer rings of the annular excitation, respectively, and their expressions are as follows: ； ； ； In the formula, Angular frequency, The density of the plate, For the bending vibration stiffness of the plate, It is Young's modulus. For the thickness of the plate, Poisson's ratio, , These are the first and second kind of zero-order Bessel functions, respectively. , These are the first and second kind zero-order modified Bessel functions, respectively. , , , The nonlinear coefficient can be given by the boundary conditions and continuity conditions of the thin plate. The boundary conditions of the thin plate are zero displacement and zero displacement derivative. The continuity conditions at the excitation position are continuous displacement and continuous transverse shear force.

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