Directional strong sound dispersing system with distance measuring function and strong sound dispersing method

Abstract

The invention discloses a directional strong sound dispersing system with a distance measuring function and a strong sound dispersing method, and relates to the technical field of strong sound dispersing. The system comprises a power supply module, a control module, a distance measurement module, a signal generation module, a signal conditioning module, a power amplification module and a transducer module connected with the power amplification module. The system has the beneficial effects that the distance between a target and the system can be measured by matching with the distance measuring module; the transmitting power can be controlled according to the distance and the sound pressure level which the target can bear, and effective expelling is achieved on the basis that the target is not damaged. According to the high-directivity ultrasonic transducer, the number of the transmitting transducer module is single, the mode that the longitudinal vibration transducer annularly excites the thin circular plate is adopted, the high directivity of sound waves can be achieved, and the sound pressure level of the sound waves can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of strong sound dispersal, in particular to a directional strong sound dispersal system with a distance measurement function and a strong sound dispersal method. Background Art

[0002] At present, ultrasonic transducers are usually used to disperse special scenes or birds and animals. In ultrasonic transducers, the frequency is usually inversely proportional to the beam width, that is, the higher the frequency, the narrower the beam width (i.e. the degree of focus of the sound wave). This is because high-frequency sound waves have shorter wavelengths and can concentrate energy in a smaller area, thus producing a narrower beam.

[0003] Although high frequency can provide a narrower beam width, which is beneficial for improving the directivity of sound waves, high-frequency sound waves are also more susceptible to medium absorption and scattering during propagation, resulting in increased energy loss and shortened propagation distance. In addition, the penetration ability of high-frequency sound waves in the medium may be reduced, limiting its effectiveness in certain application scenarios. Conversely, lower-frequency sound waves have a wider beam width and can propagate over a wider area, providing greater coverage. However, low-frequency sound waves have poor directivity and may not be able to accurately focus the sound wave energy on a specific target area.

[0004] Strong sound equipment is a highly efficient sound wave emitting device that uses high sound pressure level audio signals to achieve the propagation of high-intensity sound waves, and effectively drives away targets through high-intensity noise stimulation. A high-power speaker is installed on a tripod to disperse targets within the range, but because the size of the sound source cannot be much smaller than the wavelength, it does not have good directivity, the sound waves diverge, the efficiency is low, and the effective distance is short.

[0005] [CN 115938337 A] By setting a plurality of ultrasonic transducer subarrays arranged at intervals, and two adjacent ultrasonic transducer subarrays respectively emitting ultrasonic waves of different frequency bands, it is achieved that only the intersection of the beams of two adjacent ultrasonic transducer subarrays can be demodulated to produce audible sound, thereby reducing the audible sound area of ​​the ultrasonic transducer, achieving high directivity of audible sound and shortening the propagation distance at the same time, and improving the privacy when using the ultrasonic transducer array. Compared with reference invention case 1, this invention improves the directivity of the system, but due to the large attenuation of high-frequency sound in the air, it cannot be propagated over long distances.

[0006] [CN202320057289.5] uses a transducer array with a matching circuit to produce a highly directional ultrasonic beam with an audio signal, thereby achieving long-distance propagation of sound waves. However, since the invention does not take into account the actual distance and the required power, it may cause harm to the flock of birds. Secondly, the array method increases the cost of the system and the complexity of the circuit, and the assembly is also cumbersome.

[0007] In summary, the existing inventions do not include a ranging function, and are unable to provide the required sound intensity for a specific distance, which may cause damage to the target; since the frequency and beam width are generally difficult to balance, long-distance or directional propagation is impossible. Summary of the invention

[0008] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present 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 have the distance measurement function and ensure that the long distance is not affected.

[0011] In order to solve the above technical problems, the present invention provides the following technical solutions: a directional strong sound dispersal system with a ranging function, comprising a signal generating module, which generates, transmits and receives a pulse signal for ranging in a ranging mode, generates a continuous wave for dispersing in a dispersing mode and modulates the sampled digital audio signal into a digital SPWM signal; a signal conditioning module, which is used to condition the received pulse echo signal to the input range of the signal sampling in the ranging mode and convert it into a digital pulse signal; in the dispersing mode, the input audio signal is amplitude-controlled and also is adjusted to the input range of the signal sampling and converted into a digital audio signal; a power amplification module, which is used to The pulse signal emitted by the signal generating module is amplified in the ranging mode; the digital SPWM signal modulated by the signal generating module is amplified in the dispersing mode and transmitted to the strong directional ultrasonic transducer of the transducer module, and the strong directional ultrasonic transducer emits ultrasonic waves pointing to the dispersing target; the transducer module also includes a receiving transducer, and the receiving transducer is used to receive the reflected echo from the dispersing target in the ranging mode; the ranging module is used to record the time when the pulse is emitted from the signal generating module and the time when the reflected echo is received by the receiving transducer; the control module is used to control the system to work in the ranging mode or the dispersing mode, and receive the power signal from the ranging module.

[0012] As a preferred solution of the directional strong sound dissipation system with ranging function described in the present invention, the highly directional ultrasonic transducer includes a longitudinal vibration sandwich transducer, a stepped hollow horn and a fixed boundary thin circular plate, the longitudinal vibration sandwich transducer is connected to the non-hollow end of the stepped hollow horn, and the hollow end of the stepped hollow horn is connected to the fixed boundary thin circular plate.

[0013] As a preferred solution of the directional strong sound dispersal system with ranging function described in the present invention, the signal generating module includes an FPGA signal generating and processing circuit; the FPGA signal generating and processing circuit generates a pulse signal for transmission in the ranging mode, and gives a start signal to the ranging chip, and gives an end signal to the ranging chip after receiving the echo; in the dispersal mode, a continuous wave for dispersal is generated, and the sampled digital audio signal is modulated with a sine wave and then compared with the digital triangle wave signal generated inside the FPGA to generate a digital SPWM signal.

[0014] As a preferred solution of the directional strong sound dispersal system with ranging function described in the present invention, wherein: the signal conditioning part includes a first operational amplifier, a second operational amplifier, a third operational amplifier, and an ADC sampling circuit, and the audio signal comes 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 operational amplifier and the third operational amplifier both adopt a reverse proportional operation structure, and control the amplitude of the signal by adjusting a variable resistor; the ADC sampling circuit is used to sample the conditioned analog signal and convert the analog signal into a digital signal;

[0015] As a preferred solution of the directional strong sound dispersal system with ranging function described in the present invention, wherein: the power amplifier module includes an H-bridge power amplifier circuit, and the H-bridge power amplifier circuit includes a first MOS tube, a second MOS tube, a third MOS tube, and a fourth MOS tube; the drains of the first MOS tube and the second MOS tube are connected to the power supply VCC, the source of the first MOS tube is connected to the drain of the third MOS tube, the third MOS tube is connected to the source of the fourth MOS tube, and the source of the second MOS tube is connected to the drain of the fourth MOS tube; Vt+ is led out between the first MOS tube and the third MOS tube, and Vt- is led out between the second MOS tube and the fourth MOS tube, which are respectively connected to the two ends of the strong directional ultrasonic transducer; the bases of the first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube are connected to the driving amplification signal generated by the gate driving circuit.

[0016] As a preferred solution of the directional strong sound dispersal system with ranging function described in the present invention, wherein: 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 pulse signals for measuring the start and end of the time interval; the NTN port is the interrupt signal of the TDC, which is valid at a low level and is connected to the FPGA to provide a mark for the end of the timing and reading the timing result; the RSTN is the reset signal of the TDC-GP22, which is valid at a low level and is 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; the clock crystal oscillator circuit includes a 4MHz crystal oscillator circuit and a 32KHz crystal oscillator circuit.

[0017] As a preferred solution of the directional strong sound dispersal system with ranging function described in the present invention, it also includes a power supply module, which provides power supply voltage for the signal conditioning module, the ranging module, the first operational amplifier, the second operational amplifier and the third operational amplifier of the signal generating module.

[0018] In order to solve the above technical problems, the present invention also provides the following technical solutions: a strong sound dispersal method, using the above-mentioned directional strong sound dispersal system with ranging function, including the following steps: switching the control module to the ranging mode, controlling the signal generating module to generate a transmitting pulse signal; transmitting the transmitting pulse signal to the signal conditioning module and the START pin of the time measuring module of the ranging module, and recording the start time t1; driving and amplifying the transmitting pulse signal waveform transmitted to the signal conditioning module, and acting on the strong directional ultrasonic transducer through the power amplification module to generate ultrasonic waves to be transmitted to the dispersal target; the receiving transducer receives the reflection of the dispersal target The echo signal is transmitted to the STOP pin of the time measurement module of the ranging module, and the end time t2 is recorded; the distance S to the dispersal target and the sound pressure level Lp that the target can withstand are calculated, and the sound pressure level SPL required to be emitted by the strong directional ultrasonic transducer is determined according to the sound wave attenuation law, the radiated sound power of the strong directional ultrasonic transducer is calculated, and the electric power P of the strong directional ultrasonic transducer is determined in combination with the conversion relationship between electric power and sound power; the control module switches to the dispersal mode, the control signal generation module generates an amplitude modulated wave signal, and the strong directional ultrasonic transducer emits a modulated sound wave to the dispersal target to continuously disperse the target.

[0019] As a preferred solution of the strong sound dispersal method of the present invention, the time measurement module calculates the time interval Δt between t1 and t2, Δt is read by FPGA, and then the distance S between the rangefinder and the measured target is obtained by the formula S=Δt·c / 2;

[0020] The sound pressure p that the target can withstand is calculated according to the sound pressure level Lp1 that the target can withstand. The sound pressure level Lp1 and the sound pressure p have the following relationship:

[0021] Lp1=20lgp / p ref

[0022] Where p is the sound pressure on the target, p ref is the reference sound pressure of the medium. In air, the reference sound pressure p ref The national standard value is 2×10 -5 Pa;

[0023] Assuming that the radiated sound wave propagates along the x direction, the sound pressure at a distance S from the dispersing system is:

[0024] p=p 0 e -αS

[0025] where p 0 is the sound pressure emitted by the dispersing system, α is the attenuation coefficient in the propagation medium;

[0026] The relationship between the attenuation coefficient α and the sound wave frequency f is:

[0027] α=A e ·f 2

[0028] Among them A e A is the sound transmission medium constant at normal temperature and pressure. e The value of is 1.633×10 -10 ;

[0029] According to the distance S and the attenuation relationship, the sound pressure level SPL emitted by the highly directional ultrasonic transducer of the dissipation system can be obtained, where:

[0030] SPL = 20lgp 0 / p ref

[0031] The sound intensity level that the transducer is to emit can be expressed as:

[0032] SIL=10lgI / I ref

[0033] I is the sound intensity, where I ref is the reference sound intensity of the medium. In air, the reference sound intensity I ref The national standard value is 10 - 12 W / m 2 ;

[0034] Combining the above relationship, we can get:

[0035]

[0036] Due to the characteristic impedance of air The value is close to 400N·s / m;

[0037] The expression of sound intensity I is:

[0038]

[0039] If the sound intensity I is known, the sound power W of the dissipation system can be calculated:

[0040] W=I·s

[0041] Where s is the radiation area of ​​the dissipation system;

[0042] The electric power P of the dissipation system can be expressed as:

[0043] P=U 2 / R

[0044] Where U is the applied voltage and R is the resistance;

[0045] There is the following relationship between sound power W and electrical power P:

[0046] W=P·η

[0047] Where η is the electroacoustic efficiency, which is usually taken as 50%.

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

[0049]

[0050] For the spatial observation point p located in the xz plane, the distance between it and the origin is r 1 , the outer ring of the circular plate is divided into an infinite number of small surface elements, and each small surface element is regarded as a point source. According to the superposition principle of point sources, the sound pressure of each microelement on the outer ring surface at point p can be expressed as:

[0051]

[0052] Where ω is the angular frequency and h is the thickness of the plate. is the radius, k is the wave number, u 1 、u 2 are the lateral vibration amplitudes of the inner and outer rings of the annular excitation, respectively, and their expressions are:

[0053]

[0054] Where ω is the angular frequency, is the density of the board, D = Eh 3 / [12(1-v 2 )] is the bending vibration stiffness of the plate, E is Young's modulus, h is the thickness of the plate, v is Poisson's ratio, are the zero-order Bessel functions of the first and second kinds, respectively, are the first and second zero-order modified Bessel functions, respectively. A, B, C, and D are nonlinear coefficients, which can be given by the boundary conditions and continuity conditions of the thin plate. Here, the boundary conditions of the thin plate are zero displacement and zero displacement derivative, and the continuity conditions at the excitation position are displacement continuity and transverse shear force continuity.

[0055] Beneficial effects of the present invention:

[0056] The present invention can realize long-distance directional sound transmission of audio signals by matching the generated signal with dispersing information with a strong directional ultrasonic transducer; the transmitting transducer module of the present invention is single, and the strong directional ultrasonic transducer adopts the method of ring-shaped excitation of a thin circular plate by a longitudinal vibration transducer, which can not only realize the strong directivity of sound waves, but also improve its sound pressure level; the type of the strong directional ultrasonic transducer of the present invention is a longitudinal bending mode conversion transducer, which has the characteristics of high electroacoustic efficiency of a longitudinal sandwich transducer and low radiation impedance of a bending vibration thin plate, and is more suitable for propagation in the air; it can be matched with a ranging module to measure the distance between the target and the system; the transmitting power can be controlled according to the distance and the sound pressure level that the target can withstand, so as to achieve effective dispersal without damaging the target. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0058] Figure 1 is a system block diagram of the present invention;

[0059] Figure 2 A power module of the present invention;

[0060] Figure 3 A signal generating module of the present invention;

[0061] Figure 4 A signal conditioning module of the present invention;

[0062] Figure 5 The power amplifier module of the present invention;

[0063] Figure 6 The distance measurement module of the present invention;

[0064] Figure 7 It is a schematic cross-sectional view of the structure of a high-directivity ultrasonic transducer according to Embodiment 5 of the present invention;

[0065] Figure 8 It is a schematic structural diagram of a bending vibration radiation circular plate and a hollow stepped horn according to Embodiment 5 of the present invention;

[0066] Fig. 9 is a modal diagram of a hollow stepped horn and a fixed boundary circular plate according to Embodiment 5 of the present invention;

[0067] Fig.10 is a modal diagram of a high-directivity ultrasonic transducer according to Embodiment 5 of the present invention;

[0068] Fig.11 This is a directivity diagram of a high-directivity ultrasonic transducer according to Embodiment 5 of the present invention;

[0069] Fig.12 Schematic diagram of the structure of a high-directivity ultrasonic transducer according to Embodiment 7 of the present invention;

[0070] Fig.13 It is a schematic structural diagram of a bending vibration radiation circular plate and a hollow stepped horn according to Example 7 of the present invention;

[0071] Fig.14 It is a modal diagram of a hollow stepped horn and a fixed boundary circular plate in a specific implementation example 7 of the present invention;

[0072] Fig.15 This is a modal diagram of a highly directional ultrasonic transducer according to a specific embodiment of the present invention 7;

[0073] Fig.16 This is the directivity diagram of the high-directivity ultrasonic transducer according to the specific implementation example 7 of the present invention. DETAILED DESCRIPTION

[0074] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0075] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0076] 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 term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0077] Example 1

[0078] Reference Figure 1-4 , which is the first embodiment of the present invention, and provides a directional strong sound dispersal system with a ranging function, including a signal generating module 100, which generates, transmits and receives a pulse signal for ranging in a ranging mode, generates a continuous wave for dispersing in a dispersing mode, and modulates the sampled digital audio signal into a digital SPWM signal; a signal conditioning module 200, which is used to condition the received pulse echo signal to the input range of the signal sampling in the ranging mode, and convert it into a digital pulse signal; in the dispersing mode, the input audio signal is amplitude-controlled, and it is also conditioned to the input range of the signal sampling and converted into a digital audio signal; a power amplification module 300, which is used to amplify the signal generation in the ranging mode. The module transmits a pulse signal; in the dispersing mode, the digital SPWM signal modulated by the signal generating module is amplified and transmitted to the strong directional ultrasonic transducer 401 of the transducer module, and the strong directional ultrasonic transducer transmits ultrasonic waves to the dispersing target; the transducer module 400 also includes a receiving transducer 402, which is used to receive the reflected echo from the dispersing target in the ranging mode; the ranging module 500 is used to record the time when the pulse is emitted from the signal generating module and the time when the reflected echo is received from the receiving transducer; the control module 600 is used to control the system to work in the ranging mode (generating a pulse wave) or in the dispersing mode (generating a continuous wave), and receive the power signal from the ranging module. It also includes a power supply module 700, which provides power supply voltage for the signal conditioning module, the ranging module, the first operational amplifier, the second operational amplifier and the third operational amplifier of the signal generating module.

[0079] The control module is used for mode selection and automatic switching. The signal generation module generates the signals required in the two modes and modulates the input audio signal and the carrier signal to generate a modulated signal. The signal conditioning module controls the amplitude of the received echo and the input audio signal and adjusts them to a reasonable sampling range. The power amplifier module is used to amplify the signal waveform in the two modes. The ranging module is used to measure the distance between the system and the target, evaluate the actual power required for effective dispersal, and feed it back to the control module so that the system can continue to work at this power. The transducer module is used to evaluate the distance to the target and increase the transmission distance of the dispersal signal.

[0080] The power module 700 is composed of an integrated circuit U3, an integrated circuit U4, an integrated circuit U11, an integrated circuit U12, an integrated circuit U20, an integrated circuit U21, an integrated circuit U22, and a plug-in H8. The models of the integrated circuit U3, the integrated circuit U4, and the integrated circuit U11 are B2415S-1WR3, the model of the integrated circuit U12 is TLV75733PDBVR, the integrated circuit U20 is B2415S-1WR3, the integrated circuit U21 is G2405S-2W, the integrated circuit U22 is B2405S-1WR3_C5150989, and the plug-in H8 is a 2-pin plug.

[0081] The signal generating module 100 includes an FPGA signal generating and processing circuit; the audio signal comes from a microphone signal or a computer audio signal; the FPGA signal generating and processing circuit generates a pulse signal for transmission in the ranging mode, and gives a start signal to the ranging chip, and gives an end signal to the ranging chip after receiving the echo; in the dispersing mode, a continuous wave for dispersing is generated, and the sampled digital audio signal is modulated with a sine wave and then compared with the digital triangle wave signal generated inside the FPGA to generate a digital SPWM signal.

[0082] The model of the FPGA in the signal generating module of the present invention is EP4CE6E22C8.

[0083] 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 operational amplifier and the third operational amplifier both adopt a reverse proportional operational structure and control the amplitude of the signal by adjusting a variable resistor; the ADC sampling circuit is used to sample the conditioned analog signal and convert the analog signal into a digital signal.

[0084] The signal conditioning module of the present invention is composed of integrated circuit U8, integrated circuit U9, integrated circuit U10, integrated circuit U13, integrated circuit U19A, integrated circuit U19B, integrated circuit U16, integrated circuit U17, integrated circuit U18, and plug-in RF1. The integrated circuit model is U8TPL0102-100PWR, the integrated circuit U9 model is OPA657U, the integrated circuit U10 model is AD8065ART-R2, the integrated circuit U13 model is AD9280ARS, the integrated circuit U19A is TL072IDR, the integrated circuit U19B is TL072IDR, the integrated circuit U16 is AD8130ARZ-REEL, the integrated circuit U17 and integrated circuit U18 are OPA657U, and the plug-in RF1 model is BWSMA-KE-Z001_C496549 pin.

[0085] Example 2

[0086] Reference Figure 5 , which is the second embodiment of the present invention, and is different from the previous embodiment in that: this embodiment provides a power amplifier module, the power amplifier module includes an H-bridge power amplifier circuit, the H-bridge power amplifier circuit includes a first MOS tube, a second MOS tube, a third MOS tube, and a fourth MOS tube; the drains of the first MOS tube and the second MOS tube are connected to the power supply VCC, the source of the first MOS tube is connected to the drain of the third MOS tube, and the source of the third MOS tube is connected to the source of the fourth MOS tube; the source of the second MOS tube is connected to the drain of the fourth MOS tube; Vt+ is led out between the first MOS tube and the third MOS tube, and Vt- is led out between the second MOS tube and the fourth MOS tube, which are respectively connected to two ends of the strong directional ultrasonic transducer; the bases of the first MOS tube, the second MOS tube, the third MOS tube, and the fourth MOS tube are connected to the driving amplification signal generated by the gate driving circuit.

[0087] Example 3

[0088] Reference Figure 6 , which is the third embodiment of the present invention, and is different from the previous two embodiments in that: this embodiment provides a ranging module, including an SPI communication circuit, a 4MHz and 32.768KHz clock crystal oscillator circuit, and a power supply circuit.

[0089] Among them, the START and STOP ports are pulse signals for measuring the start and end of the time interval, namely Start(t1) and End(t2); NTN is the interrupt signal of TDC, which is valid at a low level and connected to FPGA to provide a mark for reading the timing result after the timing ends; RSTN is the reset signal of TDC-GP22, which is valid at a low level and connected to FPGA; SSN, SCK, SI, and SO are four-wire ports connected to the SPI communication interface of FPGA to realize the communication between FPGA controller and TDC-GP22, and to read and write the registers of TDC-GP22 to complete the time measurement function.

[0090] 4MHz provides a high-speed clock unit for TDC-GP22 for calibration. In the measurement range, TDC-GP22 also needs a high-speed clock signal as part of the time measurement unit. The 32.768KHz reference clock is used to control the high-speed clock oscillation and clock calibration. TLV75733PDBVR is used to provide a 3.3V power supply voltage for the system to complete the power supply of the system.

[0091] Example 4

[0092] Reference Figure 1, which is the fourth embodiment of the present invention, and is different from the first three embodiments in that: this embodiment provides a strong sound dispersal method, characterized in that: the control module switches to the distance measurement mode, and the control signal generating module generates a transmitting pulse signal; the transmitting pulse signal is transmitted to the signal conditioning module and the START pin of the time measurement module of the distance measurement module, and the start time t1 is recorded; the transmitting pulse signal waveform transmitted to the signal conditioning module is driven and amplified, and acts on the strong directional ultrasonic transducer through the power amplifier module to generate ultrasonic waves to be emitted to the dispersal target; the receiving transducer receives the reflected echo signal of the dispersal target, and transmits The STOP pin of the time measurement module of the ranging module is passed to the STOP pin, and the end time t2 is recorded; the distance S between the target and the dispersal target and the sound pressure level Lp that the target can withstand are calculated, and the sound pressure level SPL required to be emitted by the strong directional ultrasonic transducer is determined according to the sound wave attenuation law, the radiated sound power of the strong directional ultrasonic transducer is calculated, and the electric power P of the strong directional ultrasonic transducer is determined in combination with the conversion relationship between electric power and sound power; the control module is switched to the dispersal mode, and the control signal generation module generates an amplitude modulated wave signal, and the strong directional ultrasonic transducer emits a modulated sound wave to the dispersal target to continuously disperse the target.

[0093] Using a directional strong sound dissipation system with a ranging function, first determine the inner and outer radii of the hollow circular tube part according to the estimated working frequency sandwich transducer size, then determine its longitudinal length according to the calculation formula of the hollow stepped horn, and finally determine the radius and thickness of the annular excitation fixed boundary thin circular plate according to 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 horn and the annular excitation fixed boundary thin circular plate is consistent with the frequency of the longitudinal sandwich transducer;

[0094] There are two modes, which are automatically switched by the control module. The ranging mode is the distance measurement stage: the FPGA processor sends a digital pulse signal time to the measurement module and the signal conditioning module respectively: to the START pin of the time measurement module, and the signal is used as the timing start signal of TDC-GP22; the signal conditioning module amplifies the pulse signal and passes it through the power amplifier, and acts on the strong directional ultrasonic transducer. The transducer sends a pulse wave, and the reflected echo pulse acts on the receiving transducer next to the strong directional ultrasonic transducer. After the echo pulse is signal conditioned, the digital signal is obtained and transmitted to the STOP of the time measurement module, and the signal is used as the timing end signal of TDC-GP22; the TDC-GP22 time measurement module calculates the time interval Δt between t1 and t2, and the FPGA reads Δt, and then the distance S between the rangefinder and the measured target is obtained by the formula S=Δt·c / 2;

[0095] The sound pressure p that the target can withstand is calculated according to the sound pressure level Lp1 that the target can withstand. The sound pressure level Lp1 and the sound pressure p have the following relationship:

[0096] Lp1=20lgp / p ref

[0097] Where p is the sound pressure on the target, p ref is the reference sound pressure of the medium. In air, the reference sound pressure p ref The national standard value is 2×10 -5 Pa;

[0098] Since the amplitude of ultrasonic waves decays exponentially with the increase of propagation distance during propagation, assuming that the radiated sound wave propagates along the x direction, the sound pressure at the distance S from the dispersing system is:

[0099] p=p 0 e -αS

[0100] where p 0 is the sound pressure emitted by the dispersing system, α is the attenuation coefficient in the propagation medium;

[0101] The relationship between the attenuation coefficient α and the sound wave frequency f is:

[0102] α=A e ·f 2

[0103] Among them A e A is the sound transmission medium constant at normal temperature and pressure. e The value of is 1.633×10 -10 ;

[0104] According to the distance S and the attenuation relationship, the sound pressure level SPL emitted by the highly directional ultrasonic transducer of the dissipation system can be obtained, where:

[0105] SPL = 20lgp 0 / p ref

[0106] The sound intensity level that the transducer is to emit can be expressed as:

[0107] SIL=10lgI / I ref

[0108] I is the sound intensity, where I ref is the reference sound intensity of the medium. In air, the reference sound intensity I ref The national standard value is 10 - 12 W / m 2 ;

[0109] Combining the above relationship, we can get:

[0110]

[0111] Due to the characteristic impedance of air The value is close to The value of is approximately 0, so the sound pressure level SPL and the sound intensity level SIL are approximately equal in value.

[0112] The expression of sound intensity I is:

[0113]

[0114] If the sound intensity I is known, the sound power W of the dissipation system can be calculated:

[0115] W=I·s

[0116] Where s is the radiation area of ​​the dissipation system;

[0117] The electric power P of the dissipation system can be expressed as:

[0118] P=U 2 / R

[0119] Where U is the applied voltage and R is the resistance;

[0120] There is the following relationship between sound power W and electrical power P:

[0121] W=P·η

[0122] Where η is the electroacoustic efficiency, which is usually taken as 50%.

[0123] The radiation directivity of the transducer module can be calculated by the following formula:

[0124]

[0125] For the spatial observation point p located in the xz plane, the distance between it and the origin is r 1 , the outer circle of the circular plate is divided into an infinite number of small surface elements, each of which is regarded as a point source;

[0126] According to the superposition principle of point sources, the sound pressure of each microelement on the outer ring surface at point p can be expressed as:

[0127]

[0128] Where ω is the angular frequency and h is the thickness of the plate. is the radius, k is the wave number, u 1 、u 2 are the lateral vibration amplitudes of the inner and outer rings of the annular excitation, respectively, and their expressions are:

[0129]

[0130] Where ω is the angular frequency, is the density of the board, D = Eh 3 / [12(1-v 2 )] is the bending vibration stiffness of the plate, E is Young's modulus, h is the thickness of the plate, v is Poisson's ratio, are the zero-order Bessel functions of the first and second kinds, respectively, They are the first and second zero-order modified Bessel functions respectively. A, B, C, and D are nonlinear coefficients, which 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 displacement continuity and lateral shear force continuity.

[0131] The highly directional ultrasonic transducers of the transducer modules may also form an array.

[0132] Example 5

[0133] Reference Figure 7-11 , which is the fifth embodiment of the present invention, and is different from the previous four embodiments in that: this embodiment provides a strong directivity ultrasonic transducer 401, including a longitudinal sandwich ultrasonic transducer 401a, a hollow stepped horn 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 horn, as well as the hollow stepped horn and the fixed boundary thin circular plate are tightly connected by bolts respectively.

[0134] In a further embodiment, the design frequency of the longitudinal sandwich transducer is 30k, wherein the material of the front cover plate is 7075 aviation aluminum, the radius is 25mm, and the length is 26mm; there are two piezoelectric ceramic rings, the material is PZT-8, the outer diameter is 25mm, the inner diameter is 8.5mm, and the thickness is 6.5mm. The polarization directions of the two piezoelectric ceramic rings are opposite, one side of the piezoelectric ceramic ring is connected to the positive lead, and the other side is connected to the negative lead, and the input voltage is 1V; the material of the rear cover plate is 45# steel, the radius is 25mm, and the length is 45mm. The resonant frequency of the longitudinal sandwich transducer is approximately 30kHz.

[0135] Reference Figure 8 , 9 The design frequency of the hollow stepped horn and the fixed boundary thin circular plate is 30k, and the material is 45# steel; the outer diameter of the hollow stepped horn is 25mm, the inner diameter is 20mm, the length of the hollow section is 57mm, the length of the solid section is 57mm, the radius R of the fixed boundary bending vibration radiation circular plate is 50mm, and the thickness h is 5mm. The characteristic frequency of the hollow stepped horn and the fixed boundary bending vibration circular plate is 30k.

[0136] The realization of the above-mentioned strong directivity 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, and by adjusting the size of the hollow stepped amplitude transformer and the bending vibration circular plate with a fixed boundary, the frequency after coupling is made the same as the resonant frequency of the longitudinal sandwich transducer at the lower end, so that the strong directivity ultrasonic transducer formed by the overall combination can operate efficiently.

[0137] Reference Fig.10 , which is the vibration mode of the highly directional ultrasonic transducer. The longitudinal sandwich transducer and the hollow stepped amplitude transformer vibrate longitudinally, the circular plate vibrates in bending, and the vibration phases inside and outside the circular plate ring excitation are the same. The overall resonant frequency of the narrow beam transducer is about 30kHz.

[0138] Reference Fig.11 , which is the radiation directivity of the transducer of implementation case 1 in the air, the main lobe is sharp, the -3dB beam width is 6.2°, the side lobe is smaller than the main lobe, and the radiation direction is mainly along the axial direction of the transducer.

[0139] It can be seen from the above that the highly directional ultrasonic transducer of this embodiment can maintain an ideal low frequency while ensuring a better beam width, that is, precise directionality when dispersing at a long distance, thereby solving the problem of the difficulty in balancing and compatibility between the frequency and beam width of traditional ultrasonic transducers.

[0140] Example 6

[0141] This is the sixth embodiment of the present invention, which is different from the first five embodiments in that: this embodiment provides a strong sound dissipation method, the material of the hollow stepped horn and the fixed boundary stepped thin circular plate is metal, which can be adjusted according to the actual application scenario, and can be aluminum alloy, titanium alloy, steel or other materials. However, it is necessary to meet the vibration frequency of the whole high-directivity ultrasonic transducer and the vibration frequency of the whole composed of the hollow stepped horn and the fixed boundary stepped thin circular plate.

[0142] The design steps are as follows: estimate the required directivity strength of the transducer, that is, the beam width of the ultrasonic wave, according to the transmission distance of the actual working scene. Calculate the operating frequency of the transducer according to the beam width, and then optimize the size of the transducer. Since the design process of the sandwich transducer is relatively mature, the hollow stepped amplitude rod and the bending vibration thin circular plate are mainly designed in an integrated manner.

[0143] Firstly, the inner and outer radii of the hollow circular tube part are determined according to the size of the sandwich transducer, and then the longitudinal length of the hollow stepped horn is determined according to the calculation formula of the hollow stepped horn. Finally, the radius and thickness of the annular excitation fixed boundary thin circular plate are determined according to the finite element simulation. The displacement distribution on the surface of the thin circular plate is obtained by finite element simulation, and then steps are added in the corresponding anti-phase area 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 other parts, so that the frequency of the whole composed of the hollow stepped horn and the annular excitation fixed boundary stepped thin circular plate is consistent with the frequency of the longitudinal sandwich transducer.

[0144] The frequency equation of the stepped hollow horn is as follows:

[0145]

[0146] The radiation directivity of the transducer module can be calculated by the following formula:

[0147]

[0148] in

[0149]

[0150] Where ω is the angular frequency, h 1 、h 2 are the fixed boundary step thin circular plate substrate and the thickness of the step respectively. is the radius, k is the wave number, u 1 、u 2 、u 3 、u 4 are the transverse vibration velocity amplitudes of each part of the fixed boundary stepped thin circular plate, and their expressions are as follows:

[0151]

[0152] In the formula, is the density of the board, D = Eh 3 / [12(1-v 2 )] is the bending vibration stiffness of the plate, E is Young's modulus, h is the thickness of the plate, and v is Poisson's ratio.

[0153] are the zero-order Bessel functions of the first and second kinds, respectively, are the first and second zero-order modified Bessel functions, respectively. A, B, C, and D are nonlinear coefficients, which can be given by the boundary conditions and continuity conditions of the thin plate. Here, the boundary conditions of the thin plate are zero displacement and zero displacement derivative. The continuity conditions at the excitation position are displacement continuity and transverse shear force continuity. Substituting the boundary conditions and continuity conditions into the above formulas can calculate the far-field directivity and radiated sound pressure of the circular plate.

[0154] The radiation directivity of the highly directional transducer can be calculated by combining the above relationship, where the directivity opening angle range is 5° to 12°.

[0155] Example 7

[0156] Reference Figure 12-16 , which is the seventh embodiment of the present invention, and which is different from the first six embodiments in that: compared with the above-mentioned embodiment 4, the difference between this embodiment and the above-mentioned embodiment 4 is that, Fig.12 The present invention provides another highly directional ultrasonic transducer, comprising a longitudinal sandwich ultrasonic transducer, a hollow stepped horn 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 horn and the fixed boundary stepped thin circular plate are tightly connected by bolts.

[0157] Reference Fig.12 , Fig.13 The design frequency of the longitudinal sandwich transducer is about 30k, wherein the material of the front cover is 7075 aviation aluminum, the radius is 25mm, and the length is 26mm; there are two piezoelectric ceramic rings, the material is PZT-8, the outer diameter is 25mm, the inner diameter is 8.5mm, and the thickness is 6.5mm. The polarization directions of the two piezoelectric ceramic rings are opposite, one side of the piezoelectric ceramic ring is connected to the positive lead, and the other side is connected to the negative lead, and the input voltage is 1V; the material of the rear cover is 45# steel, the radius is 25mm, and the length is 45mm.

[0158] Reference Fig.14 The design frequency of the hollow stepped horn coupled with the fixed boundary stepped thin circular plate is 30k, and the material is 45# steel. The outer diameter of the hollow stepped horn is 25mm, the inner diameter is 20mm, the length of the hollow section is 37mm, the length of the solid section is 37mm, and the base radius a of the fixed boundary stepped thin circular plate is 4 65mm, thickness h 1 5mm. Step inner radius a 1 is 15mm, outer radius a 3 is 35mm, the total height of the step is h 2 The frequency of the hollow stepped horn coupled with the fixed boundary stepped thin circular plate is 30.151k.

[0159] The realization of the above-mentioned strong directivity 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 axially toward the circular plate, and by adjusting the size of the hollow stepped amplitude rod and the fixed boundary stepped thin circular plate, the overall resonant frequency after coupling is made the same as the resonant frequency of the longitudinal sandwich transducer at the lower end, so that the strong directivity ultrasonic transducer can operate efficiently at this frequency.

[0160] Firstly, the inner and outer radii of the hollow circular tube part are determined according to the size of the sandwich transducer, and then the longitudinal length of the hollow stepped horn is determined according to the calculation formula of the hollow stepped horn. Finally, the radius and thickness of the annular excitation fixed boundary thin circular plate are determined according to the finite element simulation. The displacement distribution on the surface of the thin circular plate is obtained by finite element simulation, and then steps are added in the corresponding anti-phase area 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 other parts, so that the frequency of the whole composed of the hollow stepped horn and the annular excitation fixed boundary stepped thin circular plate is consistent with the frequency of the longitudinal sandwich transducer.

[0161] Reference Fig.15 , which is the vibration mode of the highly directional ultrasonic transducer, the longitudinal sandwich transducer and the hollow stepped amplitude transformer perform longitudinal vibration, the fixed boundary stepped thin circular plate performs bending vibration, and the vibration phase inside and outside the circular plate annular excitation is the same, and the overall resonant frequency of the narrow beam transducer is 30.072kHz.

[0162] Reference Fig.16 , which is the radiation directivity of the transducer of the implementation example 1 in the air, the main lobe is sharp, the -3dB beam width is 6.2°, the side lobe is smaller than the main lobe, and the radiation direction is mainly along the axial direction of the transducer.

[0163] From the above, it can be seen that, similarly, the highly directional ultrasonic transducer of this embodiment can maintain an ideal low frequency while ensuring a better beam width, that is, precise directionality when dispersing at a long distance, thereby solving the problem of the difficulty in balancing the compatibility of the frequency and beam width of traditional ultrasonic transducers.

[0164] Importantly, it should be noted that the construction and arrangement of the present application shown in a number of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible without substantially departing from the novel teachings and advantages of the subject matter described in the application (e.g., mounting arrangements, use of materials, color, changes in orientation, etc.). For example, the 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 element may be changed or changed. Therefore, all such modifications are intended to be included within the scope of the present invention. The order or sequence of any process or method steps may be changed or reordered 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 is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the present invention is not limited to a specific embodiment, but extends to a variety of modifications that still fall within the scope of the appended claims.

[0165] Additionally, in an effort to provide a concise description of example embodiments, all features of an actual implementation may not be described.

[0166] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0167] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A directional strong sound dispersal system with ranging function, characterized by: A signal generating module, used for generating, transmitting and receiving pulse signals for ranging in ranging mode, generating continuous waves for dispersing in dispersing mode and modulating the sampled digital audio signal into a digital SPWM signal; The signal conditioning module is used to condition the received pulse echo signal to the input range of the signal sampling in the ranging mode and convert it into a digital pulse signal; in the dispersal mode, the input audio signal is amplitude-controlled and also conditioned to the input range of the signal sampling and converted into a digital audio signal; A power amplifier module is used to amplify the pulse signal emitted by the signal generating module in the ranging mode; in the dispersing mode, amplify the digital SPWM signal modulated by the signal generating module and transmit it to the strong directional ultrasonic transducer of the transducer module, and the strong directional ultrasonic transducer emits ultrasonic waves directed to the dispersing target; The transducer module further includes a receiving transducer, wherein the receiving transducer is used to receive a reflected echo signal from a scattering target in a ranging mode; A distance measuring module, used for recording the time when the pulse signal is transmitted from the signal generating module and the time when the reflected echo signal is received from the receiving transducer; The control module is used to control the system to work in the ranging mode or the dispersal mode, and receive the power signal from the ranging module.

2. The directional strong sound dispersal system with ranging function as claimed in claim 1, characterized in that: The highly directional ultrasonic transducer comprises a longitudinal vibration sandwich transducer, a stepped hollow horn and a fixed boundary thin circular plate, wherein the longitudinal vibration sandwich transducer is connected to the non-hollow end of the stepped hollow horn, and the hollow end of the stepped hollow horn is connected to the fixed boundary thin circular plate.

3. The directional strong sound dispersal system with ranging function as claimed in claim 2, characterized in that: The signal generation module includes an FPGA signal generation and processing circuit; The audio signal is derived from a microphone signal or a computer audio signal; The FPGA signal generation and processing circuit generates a pulse signal for transmission in the ranging mode, and gives a start signal to the ranging chip, and gives an end signal to the ranging chip after receiving the echo; in the 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 triangle wave signal generated inside the FPGA to generate a digital SPWM signal.

4. The directional strong sound dispersal system with ranging function as claimed in claim 3, characterized in that: The signal conditioning part includes a first operational amplifier, a second operational amplifier, a third operational amplifier, and an ADC sampling circuit; The first operational amplifier is used for differentially amplifying the audio signal to suppress common-mode interference; The second operational amplifier and the third operational amplifier both adopt a reverse proportional operational structure, and control the amplitude of the signal by adjusting the variable resistor; The ADC sampling circuit is used to sample the conditioned analog signal and convert the analog signal into a digital signal.

5. The directional strong sound dispersal system with ranging function as claimed in claim 4, characterized in that: The power amplifier module includes a gate drive circuit and an H-bridge power amplifier circuit, and the gate drive circuit drives and amplifies the generated digital SPWM signal; The H-bridge power amplifier circuit includes a first MOS tube, a second MOS tube, a third MOS tube, and a fourth MOS tube; The drains of the first MOS tube and the second MOS tube are connected to the power supply VCC, the source of the first MOS tube is connected to the drain of the third MOS tube, and the source of the third MOS tube is connected to the source of the fourth MOS tube; The source of the second MOS tube is connected to the drain of the fourth MOS tube; Vt+ is led out between the first MOS tube and the third MOS tube, and Vt- is led out between the second MOS tube and the fourth MOS tube, which are respectively connected to two ends of the highly directional ultrasonic transducer; The bases of the first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube are connected to the driving amplification signal generated by the gate driving circuit.

6. The directional strong sound dispersal system with ranging function as claimed in claim 5, characterized in that: 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 distance measurement module are pulse signals for measuring the start and end of the time interval; the NTN port is the interrupt signal of the TDC, which is valid at a low level and connected to the FPGA to provide a sign for the end of the timing and reading the timing result; the RSTN is the reset signal of the TDC-GP22, which is valid at a low level 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; The clock crystal oscillator circuit includes a 4MHz crystal oscillator circuit and a 32KHz crystal oscillator circuit.

7. The directional strong sound dispersal system with ranging function as claimed in claim 6, characterized in that: It also includes a power supply module, which provides power supply voltage for the signal conditioning module, the distance measurement module, the first operational amplifier, the second operational amplifier and the third operational amplifier of the signal generating module.

8. A method for dispersing strong sound, characterized in that: Using the directional strong sound dispersal system with ranging function as described in any one of claims 1 to 7 comprises the following steps: The control module switches to the ranging mode, and the control signal generating module generates a transmitting pulse signal; The transmission pulse signal is transmitted to the START pin of the time measurement module of the signal conditioning module and the ranging module, and the start time t1 is recorded; The receiving transducer receives the reflected echo of the dispersing 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 to the dispersing target and the sound pressure level Lp that the target can withstand, and determine the sound power W of the highly directional ultrasonic transducer; According to the conversion relationship between the acoustic power W and the electric power P of the transducer, the electric power P of the highly directional ultrasonic transducer is determined; The control module switches to the dispersal mode, and the control signal generation module generates an amplitude modulated wave signal, which acts on the highly directional ultrasonic transducer through the power amplifier module to generate a modulated sound wave that is emitted to the dispersal target to continuously disperse the target.

9. The method for dispersing strong sound as claimed in claim 8, characterized in that: The time measurement module calculates the time interval Δt between t1 and t2, and the FPGA reads Δt, and then obtains the distance S between the rangefinder and the measured target through the formula S=Δt·c / 2; The sound pressure p that the target can withstand is calculated according to the sound pressure level Lp1 that the target can withstand. The sound pressure level Lp1 and the sound pressure p have the following relationship: Lp1=20lgp / p ref Where p is the sound pressure on the target, p ref is the reference sound pressure of the medium. In air, the reference sound pressure p ref The national standard value is 2×10 -5 Pa; Assuming that the radiated sound wave propagates along the x direction, the sound pressure at a distance S from the dispersing system is: p=p0e -αS Where p0 is the sound pressure emitted by the dispersing system, and α is the attenuation coefficient in the propagation medium; The relationship between the attenuation coefficient α and the sound wave frequency f is: α=A e ·f 2 Among them A e A is the sound transmission medium constant at normal temperature and pressure. e The value of is 1.633×10 -10 ; According to the distance S and the attenuation relationship, the sound pressure level SPL emitted by the highly directional ultrasonic transducer of the dissipation system can be obtained, where: SPL=20lgp0 / pre f The sound intensity level that the transducer is to emit can be expressed as: SIL=10lgI / I ref I is the sound intensity, where I ref is the reference sound intensity of the medium. In air, the reference sound intensity I ref The national standard value is 10 -12 W / m 2 ; Combining the above relationship, we can get: Due to the characteristic impedance of air The value is close to 400N·s / m; The expression of sound intensity I is: If the sound intensity I is known, the sound power W of the dissipation system can be calculated: W=I·s Where s is the radiation area of ​​the dissipation system; The electric power P of the dissipation system can be expressed as: P=U 2 / R Where U is the applied voltage and R is the resistance; There is the following relationship between sound power W and electrical power P: W=P·η Where η is the electroacoustic efficiency, which is usually taken as 50%.

10. The strong sound dispersing method according to claim 9, characterized in that: The radiation directivity of the transducer module can be calculated by the following formula: For the spatial observation point p located in the xz plane, the distance between it and the origin is r1, and the outer circle of the circular plate is divided into an infinite number of small surface elements, and each small surface element is regarded as a point source; According to the superposition principle of point sources, the sound pressure of each microelement on the outer ring surface at point p can be expressed as: Where ω is the angular frequency, h is the thickness of the plate, is the radius, k is the wave number, u1 and u2 are the transverse vibration amplitudes of the inner and outer rings of the annular excitation, respectively, and the expression is: Where ω is the angular frequency, is the density of the board, D = Eh 3 / [12(1-v 2 )] is the bending vibration stiffness of the plate, E is Young's modulus, h is the thickness of the plate, v is Poisson's ratio, are the zero-order Bessel functions of the first and second kinds, respectively, They are the first and second zero-order modified Bessel functions respectively. A, B, C, and D are nonlinear coefficients, which 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 displacement continuity and lateral shear force continuity.

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