Self-focusing probe mud level detection system and carrier grounding prevention method

Abstract

The invention discloses a self-focusing probe mud level detection system and a carrier grounding prevention method. The detection system comprises a self-focusing ultrasonic transducer, a carrier and a signal processing module, the self-focusing ultrasonic transducer emits ultrasonic waves in water and receives reflected sound pressure signals at the same time, and the carrier releases the self-focusing ultrasonic transducer and monitors the depth position of the self-focusing ultrasonic transducer in the water; and the signal processing module is used for judging whether the sound pressure signal has a maximum value in local time or not, and calculating the sludge depth position at the current position. According to the self-focusing probe mud level detection system and the carrier grounding prevention method, the depth of the mud level can be accurately judged by analyzing the sound pressure of reflection echoes without depending on propagation time calculation of ultrasonic waves, the influence of environmental factors (such as temperature and pressure) in the traditional technology is avoided, the precision and reliability of mud level detection are effectively improved, and the method is suitable for popularization and application. And the detection process is simplified, and the method is suitable for quickly and accurately measuring the mud position in a complex underwater environment.

Description

Technical Field

[0001] The invention relates to a mud level detection system and a method for preventing a carrier from bottoming out, in particular to a self-focusing probe mud level detection system and a method for preventing a carrier from bottoming out. Background Art

[0002] In underwater environmental monitoring and dredging projects, accurate detection of the mud level (silt layer position) at the bottom of the water body is of great significance for ensuring the safe operation of vehicle equipment and optimizing operating efficiency. Traditional plane wave ultrasonic mud level detection technology relies on the calculation of ultrasonic propagation time, and estimates the position of the mud level by emitting sound waves and receiving reflected signals. However, this method is very sensitive to external environmental conditions (such as water temperature, pressure and sound speed changes), which makes it difficult to ensure the detection accuracy, especially in complex underwater environments, where the error is large. In addition, the ultrasonic propagation speed is affected by many factors such as temperature, humidity and particle concentration in water, which further increases the complexity and uncertainty of detection. Moreover, the traditional ultrasonic mud level detection method has a weak intensity of the reflected signal due to energy dispersion, especially above or below the mud level, the echo signal is not obvious enough, and it is difficult to accurately determine the mud level position. In addition, the traditional ultrasonic detection method relies on measuring the propagation time of the sound wave to calculate the mud level depth, which requires complex time measurement and sound speed correction steps, especially when the water temperature and pressure change greatly, the calculation process becomes more complicated and unreliable. In addition, in different underwater operating environments, traditional ultrasonic equipment needs to be frequently calibrated and adjusted to adapt to different water quality, temperature and other environmental conditions, which increases operational complexity and equipment maintenance costs. Summary of the invention

[0003] The purpose of the invention is to provide a self-focusing probe mud level detection system and a vehicle bottoming prevention method, which can realize rapid and accurate detection of mud level, thereby preventing the vehicle from bottoming out.

[0004] Technical solution: The self-focusing probe mud level detection system of the present invention includes a self-focusing ultrasonic transducer, a carrier and a signal processing module;

[0005] The self-focusing ultrasonic transducer is installed on a vehicle and placed in water. The self-focusing ultrasonic transducer transmits ultrasonic waves in the water and receives reflected echoes. The self-focusing ultrasonic transducer is slowly released vertically into the water by the vehicle, and the depth position of the self-focusing ultrasonic transducer in the water is monitored in real time.

[0006] The signal processing module is used to collect the reflected echo received by the self-focused ultrasonic transducer in real time to obtain the sound pressure signal, and analyze the collected sound pressure signal to determine whether the sound pressure signal has a maximum value in the local time. If the sound pressure signal has a maximum value in the local time, it indicates that the sludge position has been detected, that is, the distance between the sludge and the self-focused ultrasonic transducer at this time is the focal distance of the self-focused ultrasonic transducer, and then the depth position of the self-focused ultrasonic transducer is added to the focal distance to calculate the sludge depth position at the current position.

[0007] The present invention also provides a method for preventing a carrier from touching the bottom of a self-focusing probe mud level detection system, comprising the following steps:

[0008] Step 1, installing the self-focusing ultrasonic transducer at the lowest position of the bottom of the carrier;

[0009] Step 2, slowly releasing the vehicle vertically into the water, the self-focused ultrasonic transducer emits ultrasonic waves downward in the water, and receives reflected echoes in real time;

[0010] Step 3, the signal processing module collects the reflected echo received by the self-focused ultrasonic transducer to obtain a sound pressure signal;

[0011] Step 4: Analyze the collected sound pressure signal to determine whether the sound pressure value has a maximum value in the form of decreasing from low to high and then decreasing in a local time. If a maximum value has appeared, the time when the maximum value is reached is determined to be the time when the self-focused ultrasonic transducer detects the silt, and the current depth position H of the self-focused ultrasonic transducer is recorded. If no maximum value has appeared, return to step 2;

[0012] Step 5: The depth position H of the self-focused ultrasonic transducer is added to the focal distance F to calculate the sludge depth position at the current position as H+F;

[0013] Step 6: The signal processing module displays the detection result of the mud depth position to the user, and reminds the user that the subsequent release depth of the vehicle must not exceed F, so as to prevent the vehicle from touching the bottom.

[0014] Furthermore, in step 2, the descent speed of the vehicle slowly released vertically into the water is 5 to 10 cm / s.

[0015] Furthermore, in step 3, the acquisition frequency of the sound pressure signal is 5 to 10 Hz.

[0016] Furthermore, in step 3, after acquiring the sound pressure signal from the reflected echo received by the self-focused ultrasonic transducer, the acquired sound pressure signal is first subjected to noise reduction processing, specifically, the acquired sound pressure values ​​are averaged through a sliding window:

[0017]

[0018] Where N is the size of the sliding window, P i is the sound pressure value after smoothing, and P i As the final sound pressure value obtained in the i-th collection.

[0019] Furthermore, in step 4, the specific steps of determining whether the sound pressure value has a maximum value in the form of increasing from low to high and then decreasing within a local time are:

[0020] Step 4.1, obtain the collected sound pressure values ​​P1, P2, ..., P n , where P i represents the sound pressure value collected for the i-th time;

[0021] Step 4.2: Calculate the sound pressure difference ΔP between two consecutive sound pressure values ​​collected i for:

[0022] ΔP i =P i+1 -P i

[0023] Where P i+1 is the sound pressure value obtained by the i+1th acquisition, P i is the sound pressure value obtained in the i-th acquisition, and the sound pressure difference ΔP i Used to indicate the amplitude of change of sound pressure value;

[0024] Step 4.3, for each sound pressure difference ΔP i Conduct analysis and judgment:

[0025] If the sound pressure difference ΔP i-1 >E, -Y≤ΔP i ≤Y and ΔP i+1 <-E, it indicates that the sound pressure value changes from low to high and then decreases, that is, the sound pressure value P collected for the i-th time i is a maximum value, otherwise return to step 4.1 to continue obtaining the collected sound pressure value.

[0026] Furthermore, in step 4.3, the value range of E is 0.001 to 0.005 Pa, and the value range of Y is 0 to 0.001 Pa.

[0027] Compared with the prior art, the present invention has the following beneficial effects: by analyzing the sound pressure of the reflected echo, the depth of the mud level can be accurately determined without relying on the calculation of the propagation time of the ultrasonic wave, thus avoiding the influence of environmental factors (such as temperature, pressure, etc.) in traditional technology, effectively improving the accuracy and reliability of mud level detection, and simplifying the detection process, which is suitable for quickly and accurately measuring the mud level in complex underwater environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the system model structure of the present invention;

[0029] Figure 2 It is a focusing schematic diagram of the self-focusing ultrasonic transducer of the present invention;

[0030] Figure 3 The geometric model of the focus of the self-focusing ultrasonic transducer of the present invention at the mud level;

[0031] Figure 4 It is a diagram of different focal positions of the self-focusing ultrasonic transducer of the present invention and a time domain diagram of the sound pressure of the emitted ultrasonic signal;

[0032] Figure 5 It is the maximum peak fitting curve of the three positions of the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0034] like Figure 1 As shown, the self-focusing probe mud level detection system disclosed in the present invention includes: a self-focusing ultrasonic transducer, a carrier and a signal processing module;

[0035] The self-focusing ultrasonic transducer is installed on a vehicle and placed in water. The self-focusing ultrasonic transducer transmits ultrasonic waves in the water and receives reflected echoes. The self-focusing ultrasonic transducer is slowly released vertically into the water by the vehicle, and the depth position of the self-focusing ultrasonic transducer in the water is monitored in real time.

[0036] The signal processing module is used to collect the reflected echo received by the self-focused ultrasonic transducer in real time to obtain the sound pressure signal, and analyze the collected sound pressure signal to determine whether the sound pressure signal has a maximum value in the local time. If the sound pressure signal has a maximum value in the local time, it indicates that the sludge position has been detected, that is, the distance between the sludge and the self-focused ultrasonic transducer at this time is the focal distance of the self-focused ultrasonic transducer, and then the depth position of the self-focused ultrasonic transducer is added to the focal distance to calculate the sludge depth position at the current position.

[0037] The present invention also provides a method for preventing a carrier from touching the bottom of a self-focusing probe mud level detection system, comprising the following steps:

[0038] Step 1, installing the self-focusing ultrasonic transducer at the lowest position of the bottom of the carrier;

[0039] Step 2, slowly releasing the vehicle vertically into the water, the self-focused ultrasonic transducer emits ultrasonic waves downward in the water, and receives reflected echoes in real time;

[0040] Step 3, the signal processing module collects the reflected echo received by the self-focused ultrasonic transducer to obtain a sound pressure signal;

[0041] Step 4: Analyze the collected sound pressure signal to determine whether the sound pressure value has a maximum value in the form of decreasing from low to high and then decreasing in a local time. If a maximum value has appeared, the time when the maximum value is reached is determined to be the time when the self-focused ultrasonic transducer detects the silt, and the current depth position H of the self-focused ultrasonic transducer is recorded. If no maximum value has appeared, return to step 2;

[0042] Step 5: Add the depth position H of the self-focused ultrasonic transducer to the focal distance F to calculate the sludge depth position at the current position as H+F, such as Figure 2 As shown, the focal distance of the self-focusing ultrasonic transducer is F;

[0043] Step 6: The signal processing module displays the detection result of the mud depth position to the user, and reminds the user that the subsequent release depth of the vehicle must not exceed F, so as to prevent the vehicle from touching the bottom.

[0044] Furthermore, in step 2, the descent speed of the vehicle slowly released vertically into the water is 5 to 10 cm / s.

[0045] Furthermore, in step 3, the acquisition frequency of the sound pressure signal is 5 to 10 Hz.

[0046] Furthermore, in step 3, after acquiring the sound pressure signal from the reflected echo received by the self-focused ultrasonic transducer, the acquired sound pressure signal is first subjected to noise reduction processing, specifically, the acquired sound pressure values ​​are averaged through a sliding window:

[0047]

[0048] Where N is the size of the sliding window, P i is the sound pressure value after smoothing, and P i As the final sound pressure value obtained in the i-th collection.

[0049] Furthermore, in step 4, the specific steps of determining whether the sound pressure value has a maximum value in the form of increasing from low to high and then decreasing within a local time are:

[0050] Step 4.1, obtain the collected sound pressure values ​​P1, P2, ..., P n , where P i represents the sound pressure value collected for the i-th time;

[0051] Step 4.2: Calculate the sound pressure difference ΔP between two consecutive sound pressure values ​​collected i for:

[0052] ΔPi =P i+1 -P i

[0053] Where P i+1 is the sound pressure value obtained by the i+1th acquisition, P i is the sound pressure value obtained in the i-th acquisition, and the sound pressure difference ΔP i Used to indicate the amplitude of change of sound pressure value;

[0054] Step 4.3, for each sound pressure difference ΔP i Conduct analysis and judgment:

[0055] If the sound pressure difference ΔP i-1 >E, -Y≤ΔP i ≤Y and ΔP i+1 <-E, it indicates that the sound pressure value changes from low to high and then decreases, that is, the sound pressure value P collected for the i-th time i is a maximum value, otherwise return to step 4.1 to continue obtaining the collected sound pressure value.

[0056] Furthermore, in step 4.3, the value range of E is 0.001 to 0.005 Pa, and the value range of Y is 0 to 0.001 Pa.

[0057] In order to verify the feasibility of the self-focused ultrasonic transducer of the present invention to transmit ultrasonic waves and receive echoes, and to judge the mud level by the size of the sound pressure signal, the following uses the multi-physics field coupling finite element simulation software COMSOL Multiphysics to simulate and analyze the echo signal intensity at different positions of the focus of the self-focused ultrasonic transducer (the focus is above the mud level, at the mud level, and below the mud level) and the distribution of the sound pressure field of the probe in the underwater environment.

[0058] First, establish the corresponding geometric model according to the problem to be simulated; then set the material of each unit, select the physical field to be simulated, and set it; then divide the mesh of the entire model. The accuracy of the simulation results is closely related to the mesh division. Inappropriate mesh division may make the results inaccurate or even cause the solution to not converge. Therefore, it is necessary to determine a reasonable mesh size; set the solver and calculate the results; finally, process and display the simulation results. You can process them in COMSOL, or export the data to other software for processing and drawing.

[0059] In order to obtain the sound field distribution and echo intensity of the arc-shaped focusing transducer at different positions more clearly and intuitively, the present invention adopts three different geometric models to simulate the situation at different positions. The model adopts a two-dimensional structure to reduce the calculation time of the solver. The geometric model of the focus of the self-focusing ultrasonic transducer at the mud position is as follows: Figure 3As shown in Figure 1 (the other two models only change the focus position of the self-focused ultrasonic transducer, and the other parts remain unchanged), the self-focused ultrasonic transducer is represented by an arc segment, the frequency is 1Mhz, and the focal length is 0.1m. The sound transmission medium below is water, and below the water is silt, with a thickness of 0.2m. The mud is located at the boundary between the water area and the silt. The material parameter settings are shown in Table 1. Figure 3 In the figure, the self-focusing ultrasonic transducer 1 is set in the water, and the ultrasonic wave propagates in the water area 2. When it reaches the mud level 4, on the one hand, it continues to propagate in the silt 3, and on the other hand, it is reflected into the water area 2, and a large sound pressure signal is generated at the focus 5.

[0060] Table 1 Material parameter settings

[0061] Material density Speed ​​of sound water <![CDATA[1000kg / m 3 ]]> 1485m / s silt <![CDATA[1400kg / m 3 ]]> 1550m / s

[0062] After determining the geometric model and material parameters of the simulation, it is necessary to select the appropriate physical field and set different boundary conditions according to the purpose of the simulation. The purpose of the present invention is to determine the mud position by the echo sound pressure of the ultrasound emitted by the focusing transducer. The physical field directly selects pressure acoustics and transient. The normal acceleration is added to the arc segment of the self-focused ultrasonic transducer, and a boundary probe is set here to receive the ultrasonic signal reflected back from the mud position. Plane wave radiation is selected for the boundaries on the left and right sides of the water area and the silt. Since there is concrete under the silt in reality, impedance is selected for the boundary below the silt, and the impedance size is: 8.4·10 6 Pa·s / m.

[0063] In the process of simulation using the finite element method, the accuracy of the solution depends largely on the quality of the mesh to be divided. The smaller the maximum size of the mesh and the more regular the arrangement, the higher the accuracy of the solution. However, the finer the mesh is, the more meshes are generated and the greater the amount of calculation. In order to ensure the accuracy of the solution with less calculation, it is necessary to select an appropriate cell size. In the simulation of pressure acoustics, the maximum cell size is generally set to λmax / 5. This is because when describing a complete sine wave, in order not to cause obvious distortion, 10 to 12 points are required within a sine cycle. When simulating the sound field distribution with finite elements, 10 to 12 nodes corresponding to the wavelength of the highest frequency to be solved are required. In COMSOL, the default shape function of the wave equation is quadratic polynomial interpolation. For COMSOL modeling using quadratic elements, 5 or 6 second-order elements are required for each wavelength, that is, the maximum cell size is less than λmax / 5. The water area and silt domain are divided separately.

[0064] The present invention mainly simulates and analyzes the echo signal strength when the focus of the self-focused ultrasonic transducer is located at different positions (the focus is above the mud level, at the mud level, and below the mud level) and the distribution of the sound pressure field of the probe in the underwater environment. The focus of the transducer at different positions and the time domain diagram of the sound pressure of the ultrasonic signal emitted by the transducer are shown in Figure 2. Figure 4 shown.

[0065] Figure 4 (a) The focus is on the mud level. Figure 4 (b) In this case, the self-focusing ultrasonic transducer receives the time domain signal of the reflected wave from the interface between the water and the silt. The first wave is the initial wave, that is, the ultrasonic signal emitted by the self-focusing ultrasonic transducer. The second wave is the echo, that is, the self-focusing ultrasonic transducer receives the reflected wave from the interface between the water and the silt. The maximum peak value is 0.019Pa.

[0066] Figure 4 (c) The focus is at the mud level. Figure 4 (d) In this case, the self-focusing ultrasonic transducer receives the time domain signal of the reflected wave from the interface between the water and the silt. The first wave is the initial wave, that is, the ultrasonic signal emitted by the self-focusing ultrasonic transducer, and the second wave is the echo, that is, the self-focusing ultrasonic transducer receives the reflected wave from the interface between the water and the silt, with a maximum peak value of 0.1138Pa.

[0067] Figure 4 (e) The focus is below the mud level. Figure 4 (f) In this case, the self-focusing ultrasonic transducer receives the time domain signal of the reflected wave from the interface between the water area and the silt. The first wave is the initial wave, that is, the ultrasonic signal emitted by the self-focusing ultrasonic transducer. The second wave is the echo, that is, the self-focusing ultrasonic transducer receives the reflected wave from the interface between the water area and the silt. The maximum peak value is 0.0272Pa.

[0068] The maximum peak fitting curves at the three locations are shown in Figure 5 This curve is the real-time sound pressure change curve obtained when the self-focusing ultrasonic transducer is put into water and slowly descends. As the position of the self-focusing ultrasonic transducer slowly moves downward, the closer the focus is to the mud level, and the sound pressure gradually increases. When the focus is at the mud level, the sound pressure is the maximum. The self-focusing ultrasonic transducer continues to move downward, the focus is located below the mud level, and the sound pressure gradually decreases. The accurate detection of the mud level can be achieved through this sound pressure change.

[0069] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A self-focusing probe mud level detection system, characterized in that: It includes a self-focusing ultrasonic transducer, a carrier and a signal processing module; The self-focusing ultrasonic transducer is installed on a vehicle and placed in water. The self-focusing ultrasonic transducer transmits ultrasonic waves in the water and receives reflected echoes. The self-focusing ultrasonic transducer is slowly released vertically into the water by the vehicle, and the depth position of the self-focusing ultrasonic transducer in the water is monitored in real time. The signal processing module is used to collect the reflected echo received by the self-focused ultrasonic transducer to obtain the sound pressure signal, and analyze the collected sound pressure signal to determine whether the sound pressure signal has a maximum value in the local time. If the sound pressure signal has a maximum value in the local time, it indicates that the sludge position has been detected, that is, the distance between the sludge and the self-focused ultrasonic transducer at this time is the focal distance of the self-focused ultrasonic transducer, and then the depth position of the self-focused ultrasonic transducer is added to the focal distance to calculate the sludge depth position at the current position.

2. A method for preventing a carrier from touching the bottom of a self-focusing probe mud level detection system according to claim 1, characterized in that: The steps include: Step 1, installing the self-focusing ultrasonic transducer at the lowest position of the bottom of the carrier; Step 2, slowly releasing the vehicle vertically into the water, the self-focused ultrasonic transducer emits ultrasonic waves downward in the water, and receives reflected echoes in real time; Step 3, the signal processing module collects the reflected echo received by the self-focused ultrasonic transducer to obtain a sound pressure signal; Step 4: Analyze the collected sound pressure signal to determine whether the sound pressure value has a maximum value in the form of decreasing from low to high and then decreasing in a local time. If a maximum value has appeared, the time when the maximum value is reached is determined to be the time when the self-focused ultrasonic transducer detects the silt, and the current depth position H of the self-focused ultrasonic transducer is recorded. If no maximum value has appeared, return to step 2; Step 5: The depth position H of the self-focused ultrasonic transducer is added to the focal distance F to calculate the sludge depth position at the current position as H+F; Step 6: The signal processing module displays the detection result of the mud depth position to the user, and reminds the user that the subsequent release depth of the vehicle must not exceed F, so as to prevent the vehicle from touching the bottom.

3. The method for preventing a carrier from touching the bottom of a self-focusing probe mud level detection system according to claim 2, characterized in that: In step 2, the vehicle is slowly released vertically into the water at a descent speed of 5 to 10 cm / s.

4. The method for preventing a carrier from touching the bottom of a self-focusing probe mud level detection system according to claim 2, characterized in that: In step 3, the acquisition frequency of the sound pressure signal is 5 to 10 Hz.

5. The method for preventing a carrier from touching the bottom of a self-focusing probe mud level detection system according to claim 2, characterized in that: In step 3, after acquiring the sound pressure signal from the reflected echo received by the self-focused ultrasonic transducer, the acquired sound pressure signal is first subjected to noise reduction processing, specifically, the acquired sound pressure values ​​are averaged through a sliding window: Where N is the size of the sliding window, P i is the sound pressure value after smoothing, and P i As the final sound pressure value obtained in the i-th collection.

6. The method for preventing a carrier from touching the bottom of a self-focusing probe mud level detection system according to claim 2, characterized in that: In step 4, the specific steps of judging whether the sound pressure value has a maximum value in the form of increasing from low to high and then decreasing within a local time are: Step 4.1, obtain the collected sound pressure values ​​P1, P2, ..., P n , where P i represents the sound pressure value collected for the i-th time; Step 4.2: Calculate the sound pressure difference ΔP between two consecutive sound pressure values ​​collected i for: ΔP i =P i+1 -P i Where P i+1 is the sound pressure value obtained by the i+1th acquisition, P i is the sound pressure value obtained in the i-th acquisition, and the sound pressure difference ΔP i Used to indicate the amplitude of change of sound pressure value; Step 4.3, for each sound pressure difference ΔP i Conduct analysis and judgment: If the sound pressure difference ΔP i-1 >E, -Y≤ΔP i ≤Y and ΔP i+1 <-E, it indicates that the sound pressure value changes from low to high and then decreases, that is, the sound pressure value P collected for the i-th time i is a maximum value, otherwise return to step 4.1 to continue obtaining the collected sound pressure value.

7. The method for preventing a carrier from touching the bottom of a self-focusing probe mud level detection system according to claim 6, characterized in that: In step 4.3, the value range of E is 0.001~0.005Pa, and the value range of Y is 0~0.001Pa.

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