CN114675280A - A wave detection method based on multi-probe ultrasonic waves - Google Patents

Abstract

The invention relates to the technical field of acoustic wave measurement, in particular to a wave detection method based on multi-probe ultrasonic waves. The multi-probe ultrasonic sensors emit ultrasonic waves from multiple angles. When each beam of ultrasonic waves encounters a reflective surface, there will be ultrasonic waves emitted by a probe. Reflect back to the sensor direction, so as to receive the echo and measure the distance between the probe and the reflective surface, increase the ultrasonic measurement response frequency to measure the distance of each sampling point with a relatively high sampling frequency, and combine the data to get the wave curve.

Description

A wave detection method based on multi-probe ultrasonic waves

technical field

The invention relates to the technical field of acoustic wave measurement, in particular to a wave detection method based on multi-probe ultrasonic waves.

Background technique

Ultrasound is a mechanical wave with a very short wavelength. The wavelength in the air is generally shorter than 2cm (centimeter). It must rely on the medium to propagate and cannot exist in a vacuum. Ultrasonic waves travel farther in water than in air, but because of their short wavelengths, they are easily lost and scattered in air. They are not as far as audible and infrasound waves, but short wavelengths are easier to obtain anisotropic sound energy, which can be used For cleaning, gravel, sterilization, etc. There are many applications in medicine and industry. The traditional wave measurement method is mainly based on contact. In some research fields, the wave and flow field cannot be interfered, so non-contact wave measurement technology is required. The non-contact wave measurement technology uses a single probe to measure waves, but through a detailed study of the ultrasonic wave measurement method, it is found that when a single probe is used for wave measurement, the sound waves emitted when measuring the slope of the wave edge will be too large due to the reflection angle. The problem of not being able to receive effectively, as shown in Figure 1.

SUMMARY OF THE INVENTION

The invention provides a wave detection method based on multi-probe ultrasonic waves.

The present invention is achieved through the following technical solutions:

A wave detection method based on multi-probe ultrasonic waves, using an ultrasonic sensor with Tn transmitting probes to transmit ultrasonic waves, wherein the transmitting probe T1 transmits ultrasonic waves with a frequency of f1, and at the same time, a timer 1 is started to start timing, and after the interval time t, the transmitting probe T2 The ultrasonic wave with a frequency of f2 is emitted, and the timer 2 is started at the same time to start timing. The transmitter sends an ultrasonic wave of a frequency every time t. When the reflected ultrasonic frequency is f1, the timer 1 stops timing and reads the timer. The time of 1 is the flight time of the ultrasonic frequency f1, and so on to get the flight time of the ultrasonic frequency f2, f3...fn. The flight time of each frequency ultrasonic wave is multiplied by the speed of sound at the current temperature to get the ultrasonic probe to different reflections. Point distance data, combine all the distance data to get the wave curve.

Further, the transmitting probes include at least two, the two transmitting probes are installed in a spherical arc shape, and an included angle of 10° is set between the two probes.

Further, the frequency of the sound waves emitted by each of the transmitting probes is generated by the FPGA.

Further, the FPGA generates a series of stably changing sound wave frequencies, and the sound wave frequencies are sequentially transmitted by a transmission driving module controlled by the FPGA according to time intervals.

Further, the selection range of the sound wave frequency is 3 to 10 consecutive frequency points near the resonant frequency of the probe.

Further, the time interval is set within 1ms. When the duration of the after-wave generated by the sound wave emitted by the transmitting probe is between 2ms and 10ms, the time interval for transmitting the radio wave is shortened by increasing the transmitting probe.

Further, the received sound waves are coupled by the receiving probe and then enter the FPGA through an amplification and filtering circuit.

Further, the FPGA is internally provided with a frequency counter for detecting the frequency of the sound wave.

Further, the measurement accuracy of the frequency counter is 1 Hz.

Beneficial effects of the present invention:

A multi-probe ultrasonic wave detection method proposed by the present invention adopts multi-probe ultrasonic sensors for detection, and emits sound waves from multiple angles through the multi-probe ultrasonic sensors. When each beam of sound waves encounters a reflective surface, a probe will emit The sound wave is reflected back to the direction of the sensor, so as to receive the echo and measure the distance between the probe and the reflective surface, increase the ultrasonic measurement response frequency to measure the distance of each sampling point with a relatively high sampling frequency, and combine the data to obtain wavy curve.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

Fig. 1 is the single-probe ultrasonic sensor wave measurement schematic diagram mentioned in the background technology of the present invention;

2 is a schematic diagram 1 of a multi-probe ultrasonic sensor wave measurement based on a multi-probe ultrasonic wave detection method proposed by the present invention;

FIG. 3 is a second schematic diagram of wave measurement by a multi-probe ultrasonic sensor of a multi-probe ultrasonic wave detection method proposed by the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments. Obviously, the described embodiments are some, but not all, embodiments of the present invention. The components of the embodiments of the invention generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

It should be noted that the embodiments of the present invention and the features of the embodiments may be combined with each other unless there is conflict. Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the description. All are differences from other embodiments, and the same and similar parts of each embodiment can be referred to each other.

Example 1

Referring to Figure 2, a multi-probe ultrasonic wave detection method uses ultrasonic sensors of multiple transmitting probes to transmit sound waves, each transmitting probe respectively transmits ultrasonic waves of different fixed frequencies, and starts timing after each transmitting probe emits ultrasonic waves, The transmitted ultrasonic wave meets the target and returns and is received by the receiving probe. The fixed frequency of the reflected ultrasonic wave is measured by the measuring device. When the fixed frequency of the reflected ultrasonic wave is the same as the fixed frequency of the transmitted ultrasonic wave, the timing is stopped, and the start timing to the stop timing. The time period is the flight time of the ultrasonic wave emitted by the probe, and the distance can be measured by bringing the flight time into the measurement distance formula. The transmitting probe includes at least two, and the two transmitting probes are installed in a spherical arc and two There is an included angle of 10° between the two probes, which solves the problem that the ultrasonic wave emitted when measuring the slope of the wave edge cannot be effectively received due to the too large reflection angle. Generated by the FPGA, the FPGA generates a series of stably changing ultrasonic frequencies, the ultrasonic frequencies are transmitted in turn by the transmission drive module controlled by the FPGA according to the time interval, and the selection range of the ultrasonic frequencies is the continuous 3~10 near the resonant frequency of the probe. For each frequency point, the time interval is set within 1ms. When the duration of the after-wave generated by the ultrasonic wave emitted by the transmitting probe is 2ms~10ms, the time interval of ultrasonic transmission is shortened by increasing the transmitting probe, and the reflected ultrasonic wave is transmitted by the receiving probe. After coupling, it enters the FPGA through the amplification and filtering circuit. The FPGA is provided with a frequency counter for detecting the ultrasonic frequency. The measurement accuracy of the frequency counter is 1Hz, which can meet the requirements of receiving and detection. The requirements for the counter are extremely low and easy to implement. .

Example 2

On the basis of Embodiment 1, this embodiment proposes a specific implementation of a multi-probe ultrasonic wave detection method.

Further, the specific implementation is as follows.

The FPGA generates a series of sending frequency sequences according to the resonant frequency of each transmitting probe. For example, when the resonant frequency is 200KHz, the sending frequency sequence is 199.5KHz, 199.6KHz, 199.7KHz, 199.8KHz, 199.9KHz, 200.0KHz, 200.1KHz, 200.2KHz , 200.3KHz, 200.4KHz and so on, where the interval of the sending frequency only needs to meet the resolution of the receiving detection and frequency measurement circuit, and the ultrasonic waves are transmitted in turn through the transmission driving module, and the sending time interval between each two frequency points is set at 1ms Within the range, when the duration of the aftermath of the transmitting probe is longer than 2ms~10ms, the method of increasing the transmitting probe is used to shorten the sending time interval.

Referring to Figure 3, a transmission frequency f1 is generated by the FPGA, sent out through the transmitting probe T1, and the timer 1 is started to start timing. After the interval time t, the FPGA generates a transmitting frequency f2 and is sent through the transmitting probe T2, and at the same time, the timer 2 is started to start timing, By analogy, the transmitter sends a sound wave of a frequency every time t, in which the frequency range of the sound wave is 3~10 frequency points near the resonant frequency of the probe, and the frequency can be reused.

The sound wave received at the receiving end is coupled by the receiving probe, and enters the FPGA through the amplification and filtering circuit. There is a frequency counter designed in the FPGA to accurately measure the sound wave frequency. The sound wave frequency can be accurate to 1Hz. When the frequency f1 is measured, the timer 1 Stop the timer, read the time of timer 1 is the flight time of the sound wave frequency f1, and so on to infer the flight time of f2, f3..., and calculate the measurement distance through the measurement distance formula.

This method is equivalent to performing a measurement every time t, and the time interval t can be set within 1ms, and is not affected by the measurement distance, thereby improving the measurement response frequency of ultrasonic ranging.

Measurement distance = flight time of each frequency sound wave * sound speed at the current temperature;

Among them, t represents the time interval between two frequency points, and this time interval needs to be greater than the length of the aftermath of the transmitted sound wave;

T1+T2 represents the total duration of the frequency f1 from the start of the transmission of the probe T1 to the reception of the frequency f1 by the receiving probe R;

V represents the speed of sound when measured at the current ambient temperature;

D represents the distance from the probe to the target reflecting surface;

；the measured distance

;

Due to the resonance of the circuit, the transmitting probe will emit a sound wave and there will be an after wave. The time length of the after wave depends on the frequency and wave number of the emitted sound wave. The residual wave of the wave is not more than 1mS, and the multi-probe is used to transmit. The main function is to improve the measurement response frequency and improve the real-time measurement in order to avoid the residual wave.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (9)

1. a wave detection method based on multi-probe ultrasonic wave, it is characterized in that, adopt the ultrasonic sensor with Tn transmitting probes to transmit ultrasonic wave, wherein transmitting probe T1 transmitting frequency is the ultrasonic wave of f1, start timer 1 to start timing simultaneously, interval time. After t, the ultrasonic wave with frequency f2 is transmitted by the transmitting probe T2, and the timer 2 is started at the same time to start timing. The transmitter sends an ultrasonic wave with a frequency every time t. When the reflected ultrasonic frequency is f1, timer 1 stops. Timing, the time of reading timer 1 is the flight time of ultrasonic frequency f1, and so on to get the flight time of ultrasonic frequency f2, f3...fn, and the flight time of each frequency ultrasonic wave is multiplied by the speed of sound at the current temperature. Get the distance data from the ultrasonic probe to different reflection points, and combine all the distance data to get the wave curve. 2. a kind of wave detection method based on multi-probe ultrasonic wave according to claim 1, is characterized in that, the transmitting probe of described ultrasonic sensor has at least two, the receiving probe has one, and two described transmitting probes are with spherical arc. It is installed in a shape with a 10° angle between the two probes. 3 . The method for wave detection based on multi-probe ultrasonic waves according to claim 2 , wherein the ultrasonic frequency emitted by each of the transmitting probes is generated by an FPGA. 4 . 4. a kind of wave detection method based on multi-probe ultrasonic wave according to claim 3, is characterized in that, described FPGA produces the ultrasonic frequency of a series of stable changes, and described ultrasonic frequency is controlled by the emission drive module of FPGA according to time interval fired sequentially. 5 . A multi-probe ultrasonic wave detection method according to claim 4 , wherein the selection range of the ultrasonic frequency is 3 to 10 consecutive frequency points near the resonant frequency of the transmitting probe. 6 . 6. a kind of wave detection method based on multi-probe ultrasonic wave according to claim 4, is characterized in that, described time interval is arranged in 1ms, when the after-wave duration that transmitting probe transmits ultrasonic wave produces is 2ms～10ms, then The time interval of ultrasonic transmission is shortened by increasing the transmitting probe. 7 . The multi-probe ultrasonic wave detection method according to claim 6 , wherein the reflected ultrasonic waves are coupled by the receiving probe and then enter the FPGA through an amplifying filter circuit. 8 . 8 . The method for wave detection based on multi-probe ultrasonic waves according to claim 7 , wherein a frequency counter for detecting ultrasonic frequencies is provided inside the FPGA. 9 . 9 . The multi-probe ultrasonic wave detection method according to claim 8 , wherein the measurement accuracy of the frequency counter is 1 Hz. 10 .

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