A PLC-based curved element array control system and a control method thereof

Abstract

The application discloses a kind of based on PLC's curved element array control system and control method thereof.The system is composed of model box, curved element sensor array, array control system and driving and acquisition system four parts.Curved element sensor array includes shock isolation pad, curved element support, excitation element, receiving element and the like structure;Array control system includes PLC, button control panel, first wiring terminal plate, second wiring terminal plate, third wiring terminal plate, fourth wiring terminal plate and the like component;Driving and acquisition system includes signal generator, power amplifier, oscilloscope, charge amplifier, host computer and the like component.The application is based on PLC controller control circuit switching work curved element, realizes the control that multiple pairs of curved element respectively generates excitation wave and accepts vibration signal under single channel condition, so that curved element sensor array can efficiently, low cost complete scanning to target soil space, obtains the three-dimensional shear wave velocity distribution mode of soil space.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering testing, specifically relating to a PLC-based bending element array control system and its control method. Background Technology

[0002] In geotechnical model tests, the small-strain shear stiffness of soil is an important parameter characterizing soil deformation and dynamic properties because it reflects changes in void ratio, pore pressure, and structural failure in fine-grained soils. The application of small-strain shear stiffness testing in describing the life-cycle characteristics of soil and rock has the following advantages: 1. Small-strain shear stiffness testing is a non-destructive testing technique with fast testing speed, suitable for real-time monitoring; 2. Combined with tomographic imaging technology, it can reflect the three-dimensional information of complex heterogeneous sites; 3. Stiffness parameters are directly obtained, and damping parameters can be obtained through simple calculations, making it more suitable for describing deformation and dynamic characteristics; 4. The test results can reflect structural changes in fine-grained soils.

[0003] The bending element method is a commonly used method for measuring small-strain shear stiffness. Its principle involves vibrating the excitation element in a bending element sensor pair within the soil, generating a shear wave that propagates through the soil and reaches the receiving element on the opposite side. The shear wave velocity is calculated based on its propagation time, and then converted into the small-strain shear stiffness of the soil. However, since geotechnical model experiments typically involve test soils with large spatial scales, the small-strain shear stiffness in three-dimensional space cannot be measured using only a few pairs of bending elements; instead, an array of numerous bending element sensors is required. Therefore, finding a reasonable method to control the bending element array is of great significance for the rational and efficient testing of small-strain shear stiffness in geotechnical model experiments.

[0004] At present, the following problems exist in the bending element array control system at home and abroad: (1) Existing bending element array systems usually involve multiple charge amplifier channels, voltage amplifier channels and oscilloscope channels, and each channel involves high costs; (2) Based on complex integrated circuit knowledge, its manufacturing and production costs are high and it is difficult to simply reproduce. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a PLC-based bending element array control system and method. This invention enables efficient and low-cost manual or automatic switching of working excitation and receiving elements during shear wave velocity testing via a PLC controller. Thus, under single amplifier channel conditions, the bending element array composed of multiple excitation and receiving elements is controlled to complete the shear wave velocity scanning of the soil space, thereby obtaining the spatial shear wave velocity of the soil.

[0006] The objective of this invention is achieved through the following technical solution: a PLC-based bending element array control system, which comprises four parts: a model box, a bending element sensor array, an array control system, and a drive and acquisition system.

[0007] The bending element sensor array includes bending element brackets fixed to both sides inside the model box by vibration isolation pads, and multiple excitation elements and receiving elements are installed on the bending element brackets.

[0008] The circuit and array control system are connected to the excitation element and the receiving element through a PLC controller, and the working status of the excitation element and the receiving element can be controlled manually or automatically.

[0009] The drive and acquisition system generates an excitation signal through a signal generator, which is transmitted to the excitation element through a circuit and array control system. A reference signal is generated and transmitted to the oscilloscope. The receiving element generates a receiving signal and transmits it to the oscilloscope. The host computer processes and calculates the propagation time of the signal in the soil.

[0010] Furthermore, the vibration isolation pad of the bending element sensor array is fixed to the bottom surface inside the model box, and the bending element support is fixed to the upper surface of the vibration isolation pad; the excitation element and the receiving element are respectively fixed on the bending element supports on both sides; the excitation element emits a single vibration under the action of excitation voltage and generates a shear wave in the soil, which reaches the receiving element on the opposite side after propagating through the soil. The receiving element receives the vibration and converts it into an electric charge signal. The vibration isolation pad can prevent the vibration emitted by the excitation element from propagating to the receiving element through the bending element support and the model box, so as to make the discrimination of the received signal more accurate.

[0011] Furthermore, the driving and acquisition system includes a signal generator, a power amplifier, an oscilloscope, a charge amplifier, and a host computer; the output of the signal generator is connected to the second channel of the power amplifier and the oscilloscope respectively, for transmitting the generated excitation signal to the circuit and array control system through the power amplifier, and simultaneously generating an identical reference signal to the second channel of the oscilloscope; the first channel of the oscilloscope is connected to the output of the charge amplifier, for receiving the received signal generated by the receiver element and amplified by the charge amplifier; the oscilloscope is connected to the host computer.

[0012] Furthermore, the array control system includes a PLC controller, a button control panel, a first terminal block, a second terminal block, a third terminal block, and a fourth terminal block;

[0013] The i-th excitation element A i It has two wires, with the positive wire connected to the tap terminal of the second terminal block, and the main terminal of the second terminal block connected to the positive output terminal of the power amplifier. The i-th excitation element A i The negative wire is connected to the i-th sub-output port Y of the PLC controller. i1Connection to the common output port COM of the PLC controller. i1 The branch terminal of the first terminal block is connected to the branch terminal, and the main terminal of the first terminal block is connected to the negative output terminal of the power amplifier.

[0014] The i-th receiving element B i It has two wires, with the positive wire connected to the tap terminal of the fourth terminal block, the main terminal of the fourth terminal block connected to the positive input terminal of the power amplifier, and the output terminal of the power amplifier connected to the first and second terminal blocks. The i-th receiver element B i The negative wire is connected to the i-th sub-output port Y of the PLC controller. i2 Connection to the common output port COM of the PLC controller. i2 It connects to the tap terminal of the third terminal block, the main terminal of the third terminal block is connected to the negative input terminal of the charge amplifier, and the input terminal of the charge amplifier is connected to the third terminal block and the fourth terminal block.

[0015] Furthermore, the circuit and array control system has a button control panel, including a manual mode button for manually controlling the operating state of the exciter and receiver, and an automatic mode button for putting the exciter and receiver into an automatic scanning operating state; it also includes a switch button for switching between manual and automatic operating modes.

[0016] Furthermore, the manual mode buttons include a "+1" button, a "-1" button, a "+n" button, and a "-n" button; the automatic mode buttons include a "start" button, a "pause" button, and a "end" button.

[0017] Furthermore, when the PLC controller is working, it first completes power-on initialization, assigns initial values ​​to each parameter, and reads the status instructions of automatic mode or manual mode to modify the "manual ready flag" and "automatic ready flag". The bending element array control system enters the manual mode or automatic mode ready state.

[0018] If manual mode is entered, the PLC controller reads the button closing instruction of the manual mode button in the button control panel to modify the counter D0 parameter value, and closes the corresponding output port Y through the conversion function P1. i1 and Y i2 To close the corresponding excitation element A i and receiver B i This will put it into working condition;

[0019] If the system enters the automatic mode ready state, the values ​​of the "Automatic Ready Flag," "Scan Flag," and "Pause Flag" are modified according to the automatic mode button. When the scanning conditions are met, the scanning mode starts. Every set time T1, the counter D1 parameter value is incremented by one, and the corresponding output port Y is closed through the conversion function P2. i1 and Y i2 To close the corresponding excitation element A i and receiver B i This will put it into working condition;

[0020] The oscilloscope measurement results are recorded in the host computer. When the counter D0 or D1 is greater than the maximum number of combinations K, the counter is reset.

[0021] On the other hand, the present invention also provides a control method for a PLC-based bending element array control system, the method comprising the following steps:

[0022] (1) Select manual or automatic mode, and select different exciter and receiver working combinations;

[0023] (2) For the selected excitation and receiving combination, the excitation signal is generated by the signal generator and sent to the power amplifier, while the same reference signal is generated and sent to the oscilloscope.

[0024] (3) The power amplifier transmits the voltage excitation signal to the excitation element in operation, which generates shear vibration in the soil. The vibration is transmitted through the soil to the receiving element in operation, generating a charge receiving signal.

[0025] (4) The charge receiving signal is transmitted to the charge amplifier for signal amplification, and finally the amplified receiving signal is transmitted to the oscilloscope.

[0026] (5) The oscilloscope transmits the reference signal and charge receiving signal to the host computer for filtering and calculates the propagation time of the signal in the soil; return to step (1) until all required work combinations are measured.

[0027] The beneficial effects of this invention are as follows: The bending element array control system provided by this invention can efficiently control the bending element array to perform spatial scanning of soil shear wave velocity, thereby obtaining the spatial shear wave velocity of the soil; logic code is written into the PLC controller, and the switching of working excitation element and working receiver element is realized through control buttons. The system structure is simple and does not involve complex integrated circuit knowledge, which facilitates later maintenance and upgrades; only one amplifier channel and two oscilloscope channels are needed to realize the scanning process of all bending element units, resulting in low overall system cost; it is divided into automatic mode and manual mode to meet the usage requirements under different conditions. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the device connection according to the present invention;

[0029] Figure 2 This is a system circuit connection diagram of the present invention;

[0030] Figure 3 This is a schematic diagram of the curved element array structure of the present invention;

[0031] Figure 4 This is a schematic diagram of the button control panel of the present invention;

[0032] Figure 5 This is a flowchart of the system operation during the experiment of the present invention;

[0033] In the diagram: 1-Model box; 2-Bending element sensor array; 3-Array control system; 4-Drive and acquisition system; 201-Vibration isolation pad; 202-Bending element bracket; 203-Excitation element; 204-Receiver element; 301-PLC controller; 302-Button control panel; 303-First terminal block; 304-Second terminal block; 305-Third terminal block; 305-Fourth terminal block; 401-Signal generator; 402-Power amplifier; 403-Oscilloscope; 404-Charge amplifier; 405-Host computer. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0035] like Figure 1 As shown, the present invention provides a PLC-based bending element array control system, which includes four parts: a model box 1, a bending element sensor array 2, an array control system 3, and a drive and acquisition system 4. The bending element sensor array 2 is fixed inside the model box 1 and connected to the array control system 3 through a circuit. The drive and acquisition system 4 is connected to the array control system 3 and the bending element sensor array 2 through a circuit.

[0036] like Figure 3 As shown, the bending element sensor array 2 includes a vibration isolation pad 201, a bending element support 202, an excitation element 203, and a receiving element 204. The vibration isolation pad 201 is fixed to the bottom surface inside the model box 1, and the bending element support 202 is fixed to the upper surface of the vibration isolation pad 201. The excitation element 203 and the receiving element 204 are respectively fixed on the bending element supports 202 on both sides. The excitation element 203 emits a single vibration under the action of the excitation voltage and generates a shear wave in the soil. After propagating through the soil, it reaches the receiving element 204 on the opposite side. The receiving element 204 receives the vibration and converts it into an electric charge signal. The vibration isolation pad 201 can prevent the vibration emitted by the excitation element 203 from propagating through the bending element support 202 and the model box 1 to the receiving element 204, so that the judgment of the received signal is more accurate.

[0037] like Figure 1 and Figure 2 As shown, the array control system 3 includes a PLC controller 301, a button control panel 302, a first terminal block 303, a second terminal block 304, a third terminal block 305, and a fourth terminal block 306; the i-th excitation element 203A i It has two wires, with the positive wire connected to the tap terminal of the second terminal block 304, and the main terminal of the second terminal block 304 connected to the positive output terminal of the power amplifier 402. The i-th excitation element 203A i The negative wire is connected to the i-th sub-output port Y of the PLC controller 301. i1 Connection to the common output port COM of PLC controller 301 i1 (include Figure 2 COM1 and COM2 are connected to the tap terminals of the first terminal block 303, and the main terminal of the first terminal block 303 is connected to the negative output terminal of the power amplifier 402; the i-th receiver element 204B i It has two wires, with the positive wire connected to the tap terminal of the fourth terminal block 306, the main terminal of the fourth terminal block 306 connected to the positive input terminal of the power amplifier 402, and the negative wire of the receiver 204 connected to the i-th sub-output port Y of the PLC controller 301. i2 Connection to the common output port COM of PLC controller 301 i2 (include Figure 2 COM3 and COM4 in the third terminal block 305 are connected to the branch terminals of the third terminal block 305, and the main terminal of the third terminal block 305 is connected to the negative input terminal of the charge amplifier 404.

[0038] like Figure 1 and Figure 2 As shown, the drive and acquisition system 4 includes a signal generator 401, a power amplifier 402, an oscilloscope 403, a charge amplifier 404, and a host computer 405. The output terminal of the signal generator 401 is connected to the second channel of the power amplifier 402 and the oscilloscope 403, respectively. The output terminal of the power amplifier 402 is connected to the first terminal block 303 and the second terminal block 304. The input terminal of the charge amplifier 404 is connected to the third terminal block 305 and the fourth terminal block 306. The first channel of the oscilloscope 403 is connected to the output terminal of the charge amplifier 404. The oscilloscope 403 is connected to the host computer 405.

[0039] As shown in Table 1 below, the button control panel 302 includes "+1", "-1", "+n", and "-n" buttons in manual mode for manually controlling the working status of the exciter 203 and receiver 204; the button control panel 302 includes "Start", "Pause", and "End" buttons in automatic mode for enabling the exciter 203 and receiver 204 to enter automatic scanning mode; and the "Manual / Automatic Switch" button in the button control panel 302 is used to switch between manual and automatic working modes.

[0040] Table 1

[0041]

[0042] like Figure 4 As shown, when the PLC controller 301 is working, it first completes the power-on initialization, assigns initial values ​​to each parameter, and reads the on / off status instructions of the "manual / automatic switch" button to modify the "manual ready flag" and "automatic ready flag", so that the control system enters the manual mode or automatic mode ready state.

[0043] If manual mode is entered, the PLC controller 301 reads the button closing instructions of the "+1", "-1", "+n", and "-n" buttons in the button control panel 302 to modify the counter D0 parameter value, and closes the corresponding output port Y through the conversion function P1. i1 and Y i2 , with closed corresponding excitation element 203A i and receiver 204B i This will put it into working condition;

[0044] If the system enters the automatic mode ready state, the values ​​of the "Automatic Ready Flag," "Scan Flag," and "Pause Flag" are modified according to the "Start," "Pause," and "End" buttons. When the scanning conditions are met, the scanning mode starts. Every set time T1, the counter D1 parameter value is incremented by one, and the corresponding output port Y is closed through the conversion function P2. i1 and Y i2 , with closed corresponding excitation element 203A i and receiver 204B i This will put it into working condition;

[0045] The oscilloscope measurement results are recorded in the host computer 405. When the counter D0 or D1 is greater than the maximum number of combinations K, the counter is reset.

[0046] This invention also provides a control method for a PLC-based bending element array control system, such as... Figure 5As shown, the method is as follows: Before the test begins, a bending element array and other test devices are installed. After the soil loading is completed, the bending element array system of the PLC is used to measure the spatial shear wave velocity of the soil. First, a manual or automatic mode is selected. If the manual mode is used, different working combinations of excitation element 203 and receiver element 204 need to be selected by pressing the operation button. If the automatic mode is used, the start button needs to be pressed to automatically switch the working combinations of excitation element 203 and receiver element 204. For the selected working combination of excitation element 203 and receiver element 204, the signal generator 401 first generates an excitation signal and transmits it to the power amplifier 4. 02. Simultaneously, an identical reference signal is generated to the second channel of the oscilloscope. The power amplifier 402 transmits the voltage excitation signal to the working excitation element 203, generating shear vibration in the soil. The vibration is transmitted through the soil to the working receiving element 204, generating a charge receiving signal. The received signal is transmitted to the charge amplifier 404 for signal amplification. Finally, the amplified received signal is transmitted to the oscilloscope 403. The oscilloscope then transmits the reference signal and the received signal to the host computer 405 for filtering and calculation of the signal propagation time in the soil. The above process is repeated every time the working combination is switched until all required working combinations have been measured.

[0047] Example 1

[0048] The experimental setup for measuring the stiffness characteristics of soil around a pile under cyclic loading in this embodiment consists of three parts: a pressure consolidation device, a cyclic loading device, and a pile-soil characteristic measurement device.

[0049] like Figure 1 As shown, the present invention provides a PLC-based bending element array control system, which includes four parts: a model box 1, a bending element sensor array 2, an array control system 3, and a drive and acquisition system 4. The bending element sensor array 2 is fixed inside the model box 1 and connected to the array control system 3 through a circuit. The drive and acquisition system 4 is connected to the array control system 3 and the bending element sensor array 2 through a circuit.

[0050] like Figure 3As shown, the bending element sensor array 2 includes a vibration isolation pad 201, a bending element support 202, an excitation element 203, and a receiving element 204. The vibration isolation pad 201 is fixed to the bottom surface inside the model box 1, and the bending element support 202 is fixed to the upper surface of the vibration isolation pad 201. A total of 8 bending element supports are used, with 4 arranged on the left side of the model box and 4 arranged on the right side, with the supports placed in pairs parallel to each other. Seven excitation elements 203 are arranged at equal intervals of 20cm on the left bending element support, and seven receiving elements 204 are arranged at equal intervals of 20cm on the right bending element support. The excitation element 203 can emit a single vibration under the action of excitation voltage and generate a shear wave in the soil. After propagating through the soil, it reaches the receiving element 204 on the opposite side. The receiving element 204 receives the vibration and converts it into an electric charge signal. The vibration isolation pad 201 can prevent the vibration emitted by the excitation element 203 from propagating to the receiving element 204 through the bending element support 202 and the model box 1, making the discrimination of the received signal more accurate.

[0051] like Figure 1 and Figure 2 As shown, the array control system 3 includes a PLC controller 301, a button control panel 302, a first terminal block 303, a second terminal block 304, a third terminal block 305, a third terminal block 306, and a fourth terminal block 306; the i-th excitation element 203A i It has two wires, with the positive wire connected to the tap terminal of the second terminal block 304. In specific implementation, since there are 28 excitation elements, the second terminal block 304 needs 28 tap terminals. The main terminal of the second terminal block 304 is connected to the positive output terminal of the power amplifier 402. The i-th excitation element 203A i The negative wire is connected to the i-th sub-output port Y of the PLC controller 301. i1 Connection to the common output port COM of PLC controller 301 i1 Connected to the tap terminal of the first terminal block 303; the main terminal of the first terminal block 303 is connected to the negative output terminal of the power amplifier 402; the i-th receiver element 204B i It has two wires, with the positive wire connected to the tap terminal of the fourth terminal block 306. In specific implementation, since there are 28 receivers 204, the fourth terminal block 306 needs 28 tap terminals. The main terminal of the fourth terminal block 306 is connected to the positive input terminal of the power amplifier 402, and the negative wire of the receiver 204 is connected to the i-th output port Y of the PLC controller 301. i2 Connection to the common output port COM of PLC controller 301 i2 It is connected to the tap terminal of the third terminal block 305, and the main terminal of the third terminal block 305 is connected to the negative input terminal of the charge amplifier 404.

[0052] like Figure 1 and Figure 2 As shown, the drive and acquisition system 4 includes a signal generator 401, a power amplifier 402, an oscilloscope 403, a charge amplifier 404, and a host computer 405. The power amplifier 402 and charge amplifier 404 are both single-input, single-output channels, while the oscilloscope 403 is a dual-input channel model. The signal generator 401 is a single-output channel model, which requires a splitter to generate and receive in-phase excitation and reception signals. The output of the signal generator 401 is connected to the second channels of the power amplifier 402 and the oscilloscope 403, respectively. The output of the power amplifier 402 is connected to the first terminal block 303 and the second terminal block 304. The input of the charge amplifier 404 is connected to the third terminal block 305 and the fourth terminal block 306. The first channel of the oscilloscope 403 is connected to the output of the charge amplifier 404. The oscilloscope 403 is connected to the host computer 405.

[0053] As shown in Table 1, the button control panel 302 includes a "+1" button, a "-1" button, a "+28" button, and a "-28" button in manual mode, used to manually control the working state of the exciter 203 and the receiver 204; when the "+1" button is pressed, the exciter 203 switches from A... i Switch to A i+1 Similarly, when the "-1" button is pressed, excitation element 203 is activated from A. i Switch to A i-1 When the "+28" button is pressed, receiver 204 receives data from B. i Switch to B i+1 Similarly, when the "-28" button is pressed, receiver 204 receives data from B. i Switch to B i-1 The button control panel 302 includes a "Start," "Pause," and "End" button in automatic mode, used to put the exciter 203 and receiver 204 into automatic scanning operation; the "Manual / Automatic Switch" button in the button control panel 302 is used to switch between manual and automatic operating modes. Figure 4 As shown, when the PLC controller 301 is working, it first completes the power-on initialization, assigns initial values ​​to each parameter, and reads the on / off status instructions of the "manual / automatic switch" button to modify the "manual ready flag" and "automatic ready flag", so that the control system enters the manual mode or automatic mode ready state.

[0054] If manual mode is entered, the PLC controller 301 reads the button closing instructions of the "+1", "-1", "+28", and "-28" buttons in the button control panel 302 to modify the counter D0 parameter value, and closes the corresponding output port Y through the conversion function P1. i1and Y i2 , with closed corresponding excitation element 203A i and receiver 204B i This will put it into working condition;

[0055] If the system enters the automatic mode ready state, the values ​​of the "Automatic Ready Flag," "Scan Flag," and "Pause Flag" are modified according to the "Start," "Pause," and "End" buttons. When the scanning conditions are met, the scanning mode starts. Every set time T1 = 0.2s, the counter D1 parameter value is incremented by one, and the corresponding output port Y is closed through the conversion function P2. i1 and Y i2 , with closed corresponding excitation element 203A i and receiver 204B i The system is brought into working condition; the oscilloscope measurement results are recorded in the host computer 405; when the counter D0 or D1 is greater than the maximum number of combinations K = 28 × 28, the counter is reset.

[0056] Example 2

[0057] like Figure 5 As shown, the present invention provides a control method for a PLC-based bending element array system, the specific steps of which are as follows:

[0058] Step 1: Installation of the test system

[0059] 1.1 Check and confirm that all the aforementioned unit components are functioning normally;

[0060] 1.2 Install the curved element array bracket, excitation element, and receiver element, and correctly connect the oscilloscope, signal generator, power amplifier, charge amplifier, host computer, PLC controller, and other components using circuitry;

[0061] Step 2: Conduct soil loading tests

[0062] 2.1 The soil was loaded using a pre-determined loading mechanism;

[0063] 2.2 Stop loading and start the curved element array system;

[0064] Step 3: Scan the spatial wave velocity of the target soil

[0065] 3.1 Close the manual / automatic button to select automatic mode;

[0066] 3.2 The initial parameter of counter D1 is 1, and the excitation element 203A1 and the receiver element 204B1 are closed;

[0067] 3.3 For the selected excitation element and receiver combination A1 and B1, the signal generator first generates an excitation signal which is transmitted to the power amplifier. At the same time, an identical reference signal is generated and transmitted to the oscilloscope channel. The power amplifier transmits the voltage excitation signal to the excitation element in operation, which generates shear vibration in the soil. The vibration is transmitted through the soil to the receiver 204 in operation, generating a charge receiving signal. The receiving signal is transmitted to the charge amplifier for signal amplification. Finally, the amplified receiving signal is transmitted to the oscilloscope. The oscilloscope then transmits the reference signal and the receiving signal to the host computer for filtering and calculation of the signal propagation time in the soil. One measurement is completed.

[0068] 3.4 Press the start button. The counter D1 parameter is updated to D1=2 after an interval of T=0.2s. At this time, the excitation element A1 and the receiver element B2 are closed, and the process in 3.3 is repeated.

[0069] 3.5 When scanning traverses all excitation and receiver working combinations A i and B i Press the End button to end the 28×28 scans. The host computer will record 28×28 sets of time-domain waveform curves for subsequent processing.

[0070] The above embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A PLC-based bending element array control system, characterized in that, The system comprises a model box (1), a curved element sensor array (2), a circuit and array control system (3) and a driving and collecting system (4); The curved element sensor array (2) comprises curved element supports (202) fixed on both sides of the inside of the model box (1) through shock insulation pads (201), and a plurality of exciting elements (203) and receiving elements (204) are arranged on the curved element supports (202) in a corresponding manner; The circuit and array control system (3) is connected with the exciting elements (203) and the receiving elements (204) through a PLC controller (301), and the working states of the exciting elements (203) and the receiving elements (204) are controlled manually or automatically; The PLC controller (301) is first powered on and initialized in operation, initial values are given to various parameters, and a state instruction of an automatic mode or a manual mode is read to modify a "manual ready flag" and an "automatic ready flag", so that the curved element array control system enters a manual mode or an automatic mode ready state; If the manual mode is entered, the PLC controller (301) reads a button closing instruction of a manual mode button in a button control panel (302) to modify a parameter value of a counter D0, and closes corresponding output ports Yi1 and Yi2 through a conversion function P1 to close corresponding exciting elements (203) Ai and receiving elements (204) Bi, so that the exciting elements (203) Ai and the receiving elements (204) Bi enter a working state; If the automatic mode ready state is entered, the "automatic ready flag", a "scan flag" and a "pause flag" are modified according to the assignment of the automatic mode button, when a scan condition is met, a scan mode is started, a parameter value of a counter D1 is increased by one every set time T1, and corresponding output ports Yi1 and Yi2 are closed through a conversion function P2 to close corresponding exciting elements (203) Ai and receiving elements (204) Bi, so that the exciting elements (203) Ai and the receiving elements (204) Bi enter a working state; The measurement results of an oscilloscope (403) are recorded in an upper computer (405), and the counters are reset when the counters D0 or D1 are greater than a maximum combination number K; The driving and collecting system (4) generates an exciting signal through a signal generator (401), the exciting signal is transmitted to the exciting elements (203) through the circuit and array control system (3), a reference signal is generated and transmitted to the oscilloscope (403), a receiving signal is generated by the receiving elements (204) and transmitted to the oscilloscope (403), and the propagation time of the signal in the soil is calculated by the upper computer (405).

2. The PLC-based curved meta-array control system of claim 1, wherein, The isolation pad (201) of the bending element sensor array (2) is fixed to the inner bottom surface of the model box (1), and the bending element support (202) is fixed to the upper surface of the isolation pad (201); the excitation element (203) and the receiving element (204) are respectively fixed to the bending element supports (202) on the two sides; the excitation element (203) emits single vibration under the action of excitation voltage and generates shear waves in the soil body, and after propagating through the soil body, the shear waves reach the receiving element (204) on the opposite side; the receiving element (204) receives the vibration and converts it into an electric charge signal; the isolation pad (201) can prevent the vibration emitted by the excitation element (203) from propagating to the receiving element (204) through the bending element support (202) and the model box (1), so that the discrimination of the receiving signal is more accurate.

3. The PLC-based curved meta-array control system of claim 1, wherein, The driving and collecting system (4) comprises a signal generator (401), a power amplifier (402), an oscilloscope (403), a charge amplifier (404) and an upper computer (405); the output end of the signal generator (401) is connected with the second channel of the power amplifier (402) and the oscilloscope (403) respectively, for transmitting the generated excitation signal to the circuit and array control system (3) through the power amplifier (402), and at the same time, transmitting the same reference signal to the second channel of the oscilloscope (403); the first channel of the oscilloscope (403) is connected with the output end of the charge amplifier (404), for receiving the receiving signal generated by the receiving element (204) and amplified by the charge amplifier (404); the oscilloscope (403) is connected to the upper computer (405).

4. The PLC-based curved meta-array control system of claim 3, wherein, The array control system (3) comprises a PLC controller (301), a button control panel (302), a first wiring end plate (303), a second wiring end plate (304), a third wiring end plate (305) and a fourth wiring end plate (306). The i-th excitation element (203)A i It has two wires, the positive wire of which is connected to the tap terminal of the second terminal block (304), and the main terminal of the second terminal block (304) is connected to the positive terminal of the output of the power amplifier (402). The i-th excitation element (203) A i The negative line is connected to the i-th sub-output port Y of the PLC controller (301). i1 Connection to the common output port COM of the PLC controller (301) i1 The terminal block is connected to the branch terminal of the first terminal block (303), and the main terminal of the first terminal block (303) is connected to the negative terminal of the output of the power amplifier (402); The i-th receiving element (204) B i has two wires, wherein the positive wire is connected with the tapping terminal of the fourth terminal plate (306), the total terminal of the fourth terminal plate (306) is connected with the input positive terminal of the power amplifier (402), the output of the power amplifier (402) is connected with the first terminal plate (303) and the second terminal plate (304), the negative wire of the i-th receiving element (204) B i is connected with the i-th output Y i2 of the PLC controller (301), the common output COM i2 of the PLC controller (301) is connected with the tapping terminal of the third terminal plate (305), the total terminal of the third terminal plate (305) is connected with the input negative terminal of the charge amplifier (404), and the input of the charge amplifier (404) is connected with the third terminal plate (305) and the fourth terminal plate (306).

5. The PLC-based curved meta-array control system of claim 1, wherein, The circuit and array control system (3) has a button control panel (302), which comprises a manual mode button for manually controlling the working state of the excitation element (203) and the receiving element (204), and an automatic mode button for enabling the excitation element (203) and the receiving element (204) to enter the automatic scanning working state; and further comprises a switching button for switching the working mode between manual and automatic.

6. The PLC-based curved meta-array control system of claim 5, wherein, The manual mode button comprises "+1" button, "-1" button, "+n" button and "-n" button; the automatic mode button comprises "start" button, "pause" button and "end" button.

7. A control method of a PLC-based curved-mirror array control system according to any one of claims 1 to 6, characterized by, The method comprises the following steps: (1) selecting manual or automatic mode, and selecting different working combinations of excitation elements (203) and receiving elements (204); (2) for the selected working combination of excitation elements (203) and receiving elements (204), generating excitation signal from the signal generator (401) to the power amplifier (402), and at the same time, generating the same reference signal to the oscilloscope. (3) The power amplifier (402) transmits the voltage excitation signal to the working excitation element (203), which generates shear vibration in the soil. The vibration is transmitted through the soil to the working receiving element (204), generating an electric charge receiving signal; (4) The electric charge receiving signal is transmitted to the charge amplifier (404) for signal amplification, and finally the amplified receiving signal is transmitted to the oscilloscope (403); (5) The oscilloscope (403) transmits the reference signal and the electric charge receiving signal to the host computer (405) for filtering processing, and calculates the propagation time of the signal in the soil; return to step (1) until all required working combinations are measured.

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