River sediment content measuring device and method based on ultrasonic attenuation

Abstract

The invention discloses a river sediment content measuring device and method based on ultrasonic attenuation, and relates to the field of river sediment concentration monitoring. A digital-to-analog conversion module in the device is arranged on an FPGA development board; the digital-to-analog conversion module is connected with the ultrasonic transmitting probe; the ultrasonic receiving probe is connected with the analog-to-digital conversion module; the analog-to-digital conversion module is connected with the FPGA development board; the ultrasonic transmitting probe is used for transmitting ultrasonic waves under the driving of the excitation signal transmitted by the digital-to-analog conversion module; the ultrasonic waves are used for spreading in a to-be-detected river in a gradual attenuation mode; the ultrasonic receiving probe is used for receiving ultrasonic waves propagating in a river to be detected, generating voltage signals according to the received ultrasonic waves and sending the voltage signals to the FPGA development board; and the FPGA development board is used for determining the sediment concentration of the river to be measured according to the voltage signal and the calibration curve. According to the invention, high-precision and wide-dynamic-range real-time measurement of the sediment content of the river can be realized.

Description

Technical Field

[0001] The present application relates to the field of river sediment concentration monitoring, and in particular to a river sediment content measurement device and method based on ultrasonic attenuation. Background Art

[0002] The sediment content of a river is an important hydrological parameter and is of great significance in water quality monitoring, ecological protection, engineering construction, etc. The relevant methods for measuring sediment content mainly include optical method, acoustic method, weighing specific gravity method, satellite remote sensing monitoring method, isotope method, etc. However, these methods for measuring sediment content cannot take into account a wide measurement range, high measurement accuracy and real-time monitoring. In addition, there are currently few acoustic sensor products on the market that can measure sediment content in real time, and there are also deficiencies in measurement accuracy. Summary of the invention

[0003] The purpose of the present application is to provide a device and method for measuring river sediment content based on ultrasonic attenuation, which can realize real-time measurement of river sediment content with high precision and wide dynamic range.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In a first aspect, the present application provides a river sediment content measurement device based on ultrasonic attenuation, comprising: an FPGA development board, an analog-to-digital conversion module, a digital-to-analog conversion module, an ultrasonic transmitting probe, and an ultrasonic receiving probe;

[0006] The digital-to-analog conversion module is arranged on the FPGA development board; the digital-to-analog conversion module is connected to the ultrasonic transmitting probe; the ultrasonic receiving probe is connected to the analog-to-digital conversion module; the analog-to-digital conversion module is connected to the FPGA development board;

[0007] The digital-to-analog conversion module is used to transmit an excitation signal; the ultrasonic transmitting probe is used to emit an ultrasonic wave driven by the excitation signal; the ultrasonic wave is used to propagate in the river to be tested in a gradually attenuated manner; the ultrasonic receiving probe is used to receive the ultrasonic wave propagating in the river to be tested, and generate a voltage signal based on the received ultrasonic wave, and send the voltage signal to the FPGA development board; the FPGA development board is used to determine the sediment concentration of the river to be tested based on the voltage signal and the calibration curve; wherein the calibration curve is obtained by fitting a voltage-sediment concentration number pair; the voltage-sediment concentration number pair includes: the voltage signal generated by the ultrasonic receiving probe when measuring rivers with different sediment concentrations and the corresponding actual sediment concentration.

[0008] Optionally, the river sediment content measuring device based on ultrasonic attenuation further includes: a power module; the power module is connected to the FPGA development board; the power module is used to supply power to the FPGA development board.

[0009] Optionally, the river sediment content measurement device based on ultrasonic attenuation further includes: a display module; the display module is arranged on the FPGA development board; the display module is used to display the voltage signal and the sediment concentration of the river to be measured.

[0010] Optionally, the river sediment content measuring device based on ultrasonic attenuation further includes: a bracket; the bracket is used to support and fix the ultrasonic transmitting probe and the ultrasonic receiving probe.

[0011] Optionally, the river sediment content measurement device based on ultrasonic attenuation further includes: an FPGA serial port; the FPGA serial port is arranged on the FPGA development board; the FPGA serial port is used to transmit the sediment concentration of the river to be measured.

[0012] Optionally, the river sediment content measurement device based on ultrasonic attenuation further includes: an FPGA switch;

[0013] The FPGA switch is arranged on the FPGA development board; the power supply module is connected to the FPGA development board through the FPGA switch.

[0014] Optionally, the river sediment content measuring device based on ultrasonic attenuation further includes: a connecting line; the analog-to-digital conversion module is connected to the FPGA development board via the connecting line.

[0015] Optionally, the river sediment content measuring device based on ultrasonic attenuation further includes: a row of needles;

[0016] The pin header is arranged on the FPGA development board; the analog-to-digital conversion module is connected to the FPGA development board via the connecting wire and the pin header in sequence.

[0017] In a second aspect, the present application provides a method for measuring river sediment content based on ultrasonic attenuation, wherein the method for measuring river sediment content based on ultrasonic attenuation is implemented by using the above-mentioned river sediment content measuring device based on ultrasonic attenuation, and the method for measuring river sediment content based on ultrasonic attenuation includes:

[0018] Placing an ultrasonic transmitting probe and an ultrasonic receiving probe in a river to be tested;

[0019] The FPGA development board controls the ultrasonic transmitting probe to emit ultrasonic waves, which propagate in the river to be tested in a gradually attenuated manner, and the ultrasonic receiving probe receives the ultrasonic waves propagating in the river to be tested, and generates a voltage signal according to the received ultrasonic waves;

[0020] The FPGA development board receives the voltage signal, and determines the sediment concentration of the river to be measured based on the voltage signal and a calibration curve; wherein the calibration curve is obtained by fitting a voltage-sediment concentration pair; the voltage-sediment concentration pair includes: the voltage signal generated by the ultrasonic receiving probe when measuring rivers with different sediment concentrations and the corresponding actual sediment concentration.

[0021] Optionally, the expression of the calibration curve is:

[0022] ln V(x)=ln V0-kc;

[0023] Among them, V(x) represents the voltage signal generated by the ultrasonic receiving probe when the ultrasonic transmitting probe and the ultrasonic receiving probe are in the river; V0 represents the voltage signal generated by the ultrasonic receiving probe when the ultrasonic transmitting probe and the ultrasonic receiving probe are in clear water; k represents the slope of the calibration curve; c represents the sediment concentration.

[0024] According to the specific embodiments provided in this application, this application has the following technical effects:

[0025] The present application provides a river sediment content measurement device and method based on ultrasonic attenuation. The ultrasonic transmitting probe in the device emits ultrasonic waves under the drive of the excitation signal emitted by the digital-to-analog conversion module. The ultrasonic receiving probe receives the ultrasonic waves propagated in an attenuated manner in the river to be measured, and generates a voltage signal according to the received ultrasonic waves. The FPGA development board determines the sediment concentration of the river to be measured according to the voltage signal and the calibration curve. The present application calculates the sediment content by measuring the attenuation of the ultrasonic wave in water, has a wide measurement range, and uses the calibration curve obtained by fitting the voltage-sediment concentration number pair to calculate the sediment concentration, which greatly reduces the influence of the sediment particle size distribution of the river to be measured on the measurement result and improves the measurement accuracy. Therefore, the present application realizes the real-time measurement of the river sediment content with high precision and wide dynamic range. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the structure of a river sediment content measuring device based on ultrasonic attenuation in one embodiment of the present application.

[0028] Figure numerals: battery—1, DC5525 power monitoring line—2, FPGA serial port—3, FGGA switch—4, pin header—5, connecting line—6, analog-to-digital conversion module—7, analog signal input line—8, display module—9, digital-to-analog conversion module—10, FPGA development board—11, data output line of digital-to-analog conversion module—12, ultrasonic receiving probe line—13, ultrasonic transmitting probe line—14, ultrasonic transmitting module—15, ultrasonic receiving probe—16, bracket—17. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0031] Among the relevant measurement methods, the optical method has higher measurement accuracy, but its measurement range is narrow due to the rapid attenuation of light in muddy water; the weighing specific gravity method has high accuracy, but the measurement speed is slow and cannot achieve real-time monitoring of sediment concentration; the satellite remote sensing monitoring method needs to rely on observation models to invert sediment concentration when measuring sediment concentration. Its accuracy is greatly affected by the model and has low universality. Different models need to be established in different waters; the isotope method has higher measurement accuracy, but on the one hand it is limited by the scarcity of radioactive sources, and on the other hand radioactivity will cause pollution to the water body; the acoustic method has a wider measurement range, but the measurement accuracy is low.

[0032] In response to the above problems, this application calculates the sediment concentration by measuring the attenuation of ultrasonic waves in the river, and has a wide measurement range. At the same time, a calibration curve is used to calculate the sediment concentration. The calibration curve is established by collecting voltage-sediment concentration pairs in rivers with different sediment concentrations in advance, which greatly reduces the impact of the sediment particle size distribution of the river to be measured on the measurement results. In addition, the high-speed and high-precision analog-to-digital conversion module is equipped with an FPGA development board to realize multiple functions such as data acquisition, signal filtering, data processing, and multi-terminal communication in an integrated manner, which can not only achieve high measurement accuracy, but also monitor sediment concentration in real time, and ensure the miniaturization and portability of the measuring instrument.

[0033] In an exemplary embodiment, Figure 1 As shown, a river sediment content measuring device based on ultrasonic attenuation is provided, including: an FPGA (Field-Programmable Gate Array) development board 11, an analog-to-digital (AD) conversion module 7, a digital-to-analog (DA) conversion module 19, an ultrasonic transmitting probe 15 and an ultrasonic receiving probe 16.

[0034] The digital-to-analog conversion module 10 is arranged on the FPGA development board 11 ; the digital-to-analog conversion module 10 is connected to the ultrasonic transmitting probe 15 ; the ultrasonic receiving probe 16 is connected to the analog-to-digital conversion module 7 ; the analog-to-digital conversion module 7 is connected to the FPGA development board 11 .

[0035] The digital-to-analog conversion module 10 is used to transmit an excitation signal; the ultrasonic transmitting probe 15 is used to emit an ultrasonic wave driven by the excitation signal; the ultrasonic wave is used to propagate in the river to be tested in a gradually attenuated manner; the ultrasonic receiving probe 16 is used to receive the ultrasonic wave propagating in the river to be tested, and generate a voltage signal according to the received ultrasonic wave, and send the voltage signal to the FPGA development board 11; the FPGA development board 11 is used to determine the sediment concentration of the river to be tested according to the voltage signal and the calibration curve. The sediment concentration of the river to be tested is used to characterize the sediment content in the river to be tested.

[0036] The calibration curve is obtained by fitting the voltage-sediment concentration number pair; the voltage-sediment concentration number pair includes: the voltage signal generated by the ultrasonic receiving probe 16 when measuring rivers with different sediment concentrations and the corresponding real sediment concentration. The real sediment concentration is measured by the drying method.

[0037] It should be noted that when obtaining the voltage-sediment concentration pairs and measuring the sediment concentration of the river to be measured, the ultrasonic transmitting probe 15 and the ultrasonic receiving probe 16 are both placed in the corresponding river, and the distance between them remains unchanged.

[0038] In another exemplary embodiment of the present application, the river sediment content measuring device based on ultrasonic attenuation also includes: a power supply module; the power supply module is connected to the FPGA development board 11; the power supply module is used to power the FPGA development board 11.

[0039] The power module includes: a battery 1; the battery is connected to the power supply interface on the FPGA development board 11 through a DC (Direct Current) 5525 power monitoring line 2 to supply power to the FPGA development board 11. The battery 2 is a 5000mAh lithium battery with a voltage of 5V and a power display indicator. When fully charged, it can power the device for more than 6 hours.

[0040] In another exemplary embodiment of the present application, the river sediment content measuring device based on ultrasonic attenuation also includes: a display module 9; the display module 9 is arranged on the FPGA development board 11; the display module 9 is used to display the voltage signal and the sediment concentration of the river to be measured.

[0041] The display module 9 in this embodiment may be a 6-digit 8-segment digital tube, which can display the collected voltage signal or the calculated sediment concentration.

[0042] In another exemplary embodiment of the present application, the river sediment content measuring device based on ultrasonic attenuation further includes: a bracket 17 ; the bracket 17 is used to support and fix the ultrasonic transmitting probe 15 and the ultrasonic receiving probe 16 .

[0043] The bracket 17 of this embodiment can be a 3D bracket, which is made by 3D printing technology and has the characteristics of corrosion resistance, no interference and no pollution. The 3D printed 3D bracket includes three parts: a base, a support column and a platform. Among them, the base is a rounded rectangular parallelepiped, 200mm long, 150mm wide and 6mm thick; the support column is an irregular column, 70mm high; the platform includes two rectangular thin sheets, one of which is 45mm long, 40mm wide and 3mm thick, and the other is 35mm long, 40mm wide and 3mm thick.

[0044] In another exemplary embodiment of the present application, the river sediment content measuring device based on ultrasonic attenuation also includes: an FPGA serial port 3; the FPGA serial port 3 is arranged on the FPGA development board 11; the FPGA serial port 3 is used to transmit the sediment concentration of the river to be measured, so as to realize communication between the FPGA development board 11 and other devices.

[0045] In another exemplary embodiment of the present application, the river sediment content measuring device based on ultrasonic attenuation also includes: an FPGA switch 4; the FPGA switch 4 is arranged on the FPGA development board 11; and the power supply module is connected to the FPGA development board 11 through the FPGA switch 4.

[0046] In another exemplary embodiment of the present application, the river sediment content measurement device based on ultrasonic attenuation further includes: a connecting line 6; the analog-to-digital conversion module 7 is connected to the FPGA development board 11 via the connecting line 6. The connecting line 6 can be a multi-head DuPont line.

[0047] In another exemplary embodiment of the present application, the river sediment content measuring device based on ultrasonic attenuation further includes: an analog signal input line 8 of an analog-to-digital conversion module 7, a data output line 12 of a digital-to-analog conversion module 10, an ultrasonic receiving probe line 13, and an ultrasonic transmitting probe line 14. The analog-to-digital conversion module 7 is connected to the analog signal input line 8, the analog signal input line 8 is connected to the ultrasonic receiving probe line 13 by welding, the digital-to-analog conversion module 10 is connected to the data output line 12, and the data output line 12 is connected to the ultrasonic transmitting probe line 14 by welding.

[0048] In another exemplary embodiment of the present application, the river sediment content measuring device based on ultrasonic attenuation further includes: a pin header 5; the pin header 5 is arranged on the FPGA development board 11; the analog-to-digital conversion module 7 is connected to the FPGA development board 11 in sequence through the connecting wire and the pin header 5. The pin header 5 can be a 40-pin pin header.

[0049] In another exemplary embodiment of the present application, the FPGA development board 11 is an Intel (Altera) FPGA development board, and the main chip used is Intel (Altera) Cyclone IV series EP4CE10F17C8. The module may further include other FPGA development boards with similar performance, such as FPGA development boards with chips such as EP4CE30, EP4CE40, etc., to ensure the accuracy and reliability of the measuring device.

[0050] In another exemplary embodiment of the present application, the digital-to-analog conversion module 10 is directly inserted into the 40-pin pin header of the FPGA development board 11, and is responsible for transmitting the excitation signal to drive the ultrasonic transmitting probe. The core of the digital-to-analog conversion module 10 is an 8-bit DA chip, model AD9708, with a sampling rate of 125MSPS, and the output voltage range of the external back-end circuit is -5V to 5V. The digital-to-analog conversion module 10 may further include other digital-to-analog conversion modules with similar performance, such as AD9764, DAC904, DAC902E, etc., to ensure the accuracy and reliability of the measuring device.

[0051] In another exemplary embodiment of the present application, the core of the analog-to-digital conversion module 7 is a 12-bit AD chip, model AD9226, with a 65MPSP sampling rate, and an input range of -5V to 5V after cooperating with an external circuit. The analog-to-digital conversion module 7 may further include other analog-to-digital conversion modules with similar performance, such as AD9248, AD9268, etc., to ensure the accuracy and reliability of the measuring device.

[0052] For example, the core of the analog-to-digital conversion module 7 may be a 14-bit AD chip, model number AD9248, with a 65MPSP sampling rate, and an input range of -5V to 5V after being matched with an external circuit.

[0053] In another exemplary embodiment of the present application, the model of the ultrasonic transmitting probe 15 is DYW-1M-01T, the operating frequency is 1MHz±5%, specifically 100kHz-10MHz, the minimum impedance is 15Ω±20%, the half-power angle is (-3dB) 2.4°±0.5, and the sharpness angle is 5.8°±1.

[0054] In another exemplary embodiment of the present application, the model of the ultrasonic receiving probe 16 is DYW-01-01E, the operating frequency is 1MHz±5%, the minimum impedance is 25Ω±20%, the half-power angle is (-3dB) 3.2°±1, and the sharpness angle is 7.5°±2.

[0055] In practical application, the specific measurement process of the above-mentioned river sediment content measurement device based on ultrasonic attenuation is as follows:

[0056] (1) The ultrasonic transmitting probe 15, the ultrasonic receiving probe 16 and the bracket 17 are partially placed in a plurality of rivers with different concentrations, and the values ​​of the voltage signals on the FPGA development board 11 are read respectively. The sediment concentration in each river is measured by the drying method to obtain voltage-sediment concentration pairs.

[0057] (2) The expression of the calibration curve is fitted according to the formula ln V(x) = ln V0-kc. In the formula, V(x) represents the voltage signal generated by the ultrasonic receiving probe 16 when the ultrasonic transmitting probe 15 and the ultrasonic receiving probe 16 are in the river (i.e., the voltage value displayed on the FPGA development board 11), V0 represents the voltage signal generated by the ultrasonic receiving probe 16 when the ultrasonic transmitting probe 15 and the ultrasonic receiving probe 16 are in clear water (i.e., the voltage value displayed on the FPGA development board 11), k represents the slope of the calibration curve, and c represents the sediment concentration.

[0058] (3) The calculation formula of sediment concentration (i.e., the calibration curve) is written into the FPGA development board 11, the sediment concentration is calculated directly through the FPGA development board 11, and the calculation result is displayed on a 6-digit 8-segment digital tube.

[0059] (4) If necessary, the sediment concentration can be transmitted to the computer through the serial communication module (i.e., FPGA serial port 3). For example, the measuring device is placed in the river to be measured, and the digital tube directly displays the sediment concentration. The FPGA serial port 3 transmits the sediment concentration of the river to be measured to the storage card at the end and further transmits it to the cloud.

[0060] In this embodiment, the program is written and downloaded to the FPGA development board 11, the circuit is built, and then the device is taken to the river to be tested. The digital-to-analog conversion module 10 will emit a sinusoidal voltage to drive the ultrasonic transmitting probe 15 to emit ultrasonic waves. After the ultrasonic waves pass through the muddy water in the river, they are attenuated and reach the ultrasonic receiving probe 16 to generate a sinusoidal voltage. The voltage value is collected by the analog-to-digital conversion module 7. The ultrasonic attenuation is proportional to the sediment content. By placing the device in muddy water with different concentrations, the voltage values ​​of the ultrasonic receiving probe 16 corresponding to different concentrations can be obtained. After fitting the standard sediment content, the voltage-sediment concentration relationship, that is, the expression of the calibration curve, can be obtained. After obtaining the voltage value in the actual measurement, the corresponding sediment concentration can be calculated through the calibration curve. The device of this embodiment provides a new idea for high-precision wide dynamic range measurement and real-time monitoring of river sediment concentration.

[0061] Based on the same inventive concept, the embodiment of the present application also provides a river sediment content measurement method based on ultrasonic attenuation using the river sediment content measurement device based on ultrasonic attenuation mentioned above. The implementation scheme for solving the problem provided by the method is similar to the implementation scheme recorded in the above-mentioned device, so the specific limitations of one or more river sediment content measurement method embodiments based on ultrasonic attenuation provided below can refer to the limitations of the river sediment content measurement device based on ultrasonic attenuation above, and will not be repeated here.

[0062] In an exemplary embodiment, a method for measuring river sediment content based on ultrasonic attenuation is provided. The method for measuring river sediment content based on ultrasonic attenuation is implemented by using the above-mentioned river sediment content measuring device based on ultrasonic attenuation. The method for measuring river sediment content based on ultrasonic attenuation includes:

[0063] (1) Place the ultrasonic transmitting probe 15 and the ultrasonic receiving probe 16 in the river to be tested.

[0064] (2) The FPGA development board 11 controls the ultrasonic transmitting probe 15 to emit ultrasonic waves, which propagate in the river to be tested in a gradually attenuated manner. The ultrasonic receiving probe 16 receives the ultrasonic waves propagating in the river to be tested and generates a voltage signal according to the received ultrasonic waves.

[0065] (3) The FPGA development board 11 receives the voltage signal and determines the sediment concentration of the river to be measured based on the voltage signal and the calibration curve; wherein the calibration curve is obtained by fitting a voltage-sediment concentration pair; the voltage-sediment concentration pair includes: the voltage signal generated by the ultrasonic receiving probe 16 when measuring rivers with different sediment concentrations and the corresponding actual sediment concentration.

[0066] As an optional implementation, the expression of the calibration curve is:

[0067] ln V(x)=ln V0-kc;

[0068] Among them, V(x) represents the voltage signal generated by the ultrasonic receiving probe 16 when the ultrasonic transmitting probe 15 and the ultrasonic receiving probe 16 are in the river; V0 represents the voltage signal generated by the ultrasonic receiving probe 16 when the ultrasonic transmitting probe 15 and the ultrasonic receiving probe 16 are in clear water; k represents the slope of the calibration curve; c represents the sediment concentration.

[0069] In practical applications, a specific implementation process of the above-mentioned river sediment content measurement method based on ultrasonic attenuation can be described as follows:

[0070] (a) Circuit construction.

[0071] 1. First, fix the ultrasound probe on the 3D printed bracket. In order to obtain a more stable effect, use waterproof tape to wrap the probe and the bracket together.

[0072] 2. Connect the power module to the FPGA development board, and connect the FPGA development board to the AD9226 module via DuPont wire.

[0073] 3. Weld the positive and negative ends of the two SMA adapter cables to the positive and negative ends of the ultrasonic transmitting probe and the ultrasonic receiving probe respectively, and then connect the two SMA adapter cables to the signal output port of the AD9708 module and the signal input port of the AD9226 module respectively.

[0074] (B) Determination of the calibration curve.

[0075] 1. Take a certain volume of clean water sample, put the probe into the water and read the receiving end voltage at this time, the reading is 693mV.

[0076] 2. Dry the two evaporating dishes, and after cooling, weigh them separately using an electronic balance and record their masses.

[0077] 3. Add appropriate amount of mud and sand to the clean water, stir for one minute, and then read the receiving end voltage.

[0078] 4. Quickly take two 50 mL water samples. In order to reduce the experimental error, this embodiment selects to take 50 mL water samples at both sides of the ultrasonic sensor probes and at the same depth as the probes, so that the concentration of the sampled sediment suspension is as close as possible to the sediment concentration between the ultrasonic probes.

[0079] 5. Pour the two water samples into evaporating dishes respectively, place the evaporating dishes on a heating plate, and evaporate the water to leave the sediment.

[0080] 6. Weigh two evaporating dishes filled with sediment and record their masses. Subtract the two masses from the mass of the empty evaporating dish to get the mass of the sediment in the two 50mL water samples. Add them together to get the sediment content in the 100mL water sample. Divide this content by 100mL to get the sediment concentration. Here, two water samples are taken for evaporation and weighing, which can both speed up the evaporation rate and reduce the error.

[0081] 7. Wash the evaporating dish, dry it on the heating table, weigh it again after cooling and record the mass. The purpose of drying the washed evaporating dish in this step is to evaporate the water and avoid the influence of residual water droplets.

[0082] 8. Repeat steps 3 to 7 to obtain sediment suspensions of different concentrations, calculate the sediment concentration using the drying method, and read the corresponding receiving end voltage. In this way, several sets of sediment concentration-voltage pairs can be obtained.

[0083] 9. According to the concentration-voltage pair obtained by the above operation, a fitting function curve is obtained to obtain the calibration curve.

[0084] (iii) Experimental testing

[0085] 1. Place the device in water tanks with different sediment concentrations and read the voltage readings on the digital tubes respectively.

[0086] 2. Use the drying method to measure the concentration of various sediments.

[0087] 3. Substitute each voltage indication into the calibration curve to calculate the predicted sediment concentration.

[0088] 4. Compare the predicted sediment concentration with the sediment concentration measured by the drying method and calculate the relative error.

[0089] (iv) Test results.

[0090] The calibration curve expression established is as follows: ln(x) = -0.062932y + 6.5297, where the voltage reading is x, the logarithm is ln(x), and the sediment concentration is y. In actual measurement, the data is shown in Table 1.

[0091] Table 1 Calibration curve verification data table

[0092]

[0093]

[0094] It can be seen from Table 1 that when measuring low concentrations, the error is relatively large; when measuring medium and high concentrations, the results are relatively accurate. In particular, in the concentration range of 1.57g / L to 3.32g / L, the error is about 5%. This shows that the application is feasible for measuring sediment concentration, has good measurement results in the medium and high concentration range, and has a wide measurement range.

[0095] Compared to other methods, such as the optical method (the measurement range is generally 0-2g / L), the acoustic method has a wider measurement range. Compared to the Acoustic Doppler Velocity Meter (ADV) and the Acoustic Doppler Current Profiler (ADCP), which do not directly measure the sediment concentration, but use indirect methods such as using the relationship between velocity data and sediment concentration to estimate the sediment concentration (the accuracy is usually around 15%), the present application also has good measurement accuracy.

[0096] The above embodiment has the characteristics of wide measurement range, high measurement accuracy, and real-time monitoring of sediment concentration.

[0097] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A river sediment content measuring device based on ultrasonic attenuation, characterized in that: The river sediment content measuring device based on ultrasonic attenuation comprises: an FPGA development board, an analog-to-digital conversion module, a digital-to-analog conversion module, an ultrasonic transmitting probe and an ultrasonic receiving probe; The digital-to-analog conversion module is arranged on the FPGA development board; the digital-to-analog conversion module is connected to the ultrasonic transmitting probe; the ultrasonic receiving probe is connected to the analog-to-digital conversion module; the analog-to-digital conversion module is connected to the FPGA development board; The digital-to-analog conversion module is used to transmit an excitation signal; the ultrasonic transmitting probe is used to emit an ultrasonic wave driven by the excitation signal; the ultrasonic wave is used to propagate in the river to be tested in a gradually attenuated manner; the ultrasonic receiving probe is used to receive the ultrasonic wave propagating in the river to be tested, and generate a voltage signal based on the received ultrasonic wave, and send the voltage signal to the FPGA development board; the FPGA development board is used to determine the sediment concentration of the river to be tested based on the voltage signal and the calibration curve; wherein the calibration curve is obtained by fitting a voltage-sediment concentration number pair; the voltage-sediment concentration number pair includes: the voltage signal generated by the ultrasonic receiving probe when measuring rivers with different sediment concentrations and the corresponding actual sediment concentration.

2. The river sediment content measuring device based on ultrasonic attenuation according to claim 1 is characterized in that: The river sediment content measuring device based on ultrasonic attenuation also includes: a power supply module; the power supply module is connected to the FPGA development board; the power supply module is used to supply power to the FPGA development board.

3. The river sediment content measuring device based on ultrasonic attenuation according to claim 1 is characterized in that: The river sediment content measuring device based on ultrasonic attenuation further includes: a display module; the display module is arranged on the FPGA development board; the display module is used to display the voltage signal and the sediment concentration of the river to be measured.

4. The river sediment content measuring device based on ultrasonic attenuation according to claim 1 is characterized in that: The river sediment content measuring device based on ultrasonic attenuation further includes: a bracket; the bracket is used to support and fix the ultrasonic transmitting probe and the ultrasonic receiving probe.

5. The river sediment content measuring device based on ultrasonic attenuation according to claim 1 is characterized in that: The river sediment content measuring device based on ultrasonic attenuation also includes: an FPGA serial port; the FPGA serial port is arranged on the FPGA development board; the FPGA serial port is used to transmit the sediment concentration of the river to be measured.

6. The river sediment content measuring device based on ultrasonic attenuation according to claim 2 is characterized in that: The river sediment content measurement device based on ultrasonic attenuation also includes: an FPGA switch; The FPGA switch is arranged on the FPGA development board; the power supply module is connected to the FPGA development board through the FPGA switch.

7. The river sediment content measuring device based on ultrasonic attenuation according to claim 1 is characterized in that: The river sediment content measuring device based on ultrasonic attenuation also includes: a connecting line; the analog-to-digital conversion module is connected to the FPGA development board via the connecting line.

8. The river sediment content measuring device based on ultrasonic attenuation according to claim 7 is characterized in that: The river sediment content measuring device based on ultrasonic attenuation also includes: a row of needles; The pin header is arranged on the FPGA development board; the analog-to-digital conversion module is connected to the FPGA development board via the connecting wire and the pin header in sequence.

9. A method for measuring river sediment content based on ultrasonic attenuation, characterized in that: The river sediment content measurement method based on ultrasonic attenuation is implemented by using the river sediment content measurement device based on ultrasonic attenuation according to any one of claims 1 to 8, and the river sediment content measurement method based on ultrasonic attenuation includes: Placing an ultrasonic transmitting probe and an ultrasonic receiving probe in a river to be tested; The FPGA development board controls the ultrasonic transmitting probe to emit ultrasonic waves, which propagate in the river to be tested in a gradually attenuated manner, and the ultrasonic receiving probe receives the ultrasonic waves propagating in the river to be tested, and generates a voltage signal according to the received ultrasonic waves; The FPGA development board receives the voltage signal, and determines the sediment concentration of the river to be measured based on the voltage signal and a calibration curve; wherein the calibration curve is obtained by fitting a voltage-sediment concentration pair; the voltage-sediment concentration pair includes: the voltage signal generated by the ultrasonic receiving probe when measuring rivers with different sediment concentrations and the corresponding actual sediment concentration.

10. The method for measuring river sediment content based on ultrasonic attenuation according to claim 9, characterized in that: The expression of the calibration curve is: ln V(x)=ln V0-kc; Among them, V(x) represents the voltage signal generated by the ultrasonic receiving probe when the ultrasonic transmitting probe and the ultrasonic receiving probe are in the river; V0 represents the voltage signal generated by the ultrasonic receiving probe when the ultrasonic transmitting probe and the ultrasonic receiving probe are in clear water; k represents the slope of the calibration curve; c represents the sediment concentration.

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