A method for acquiring multi-channel high-frequency signals from fiber Bragg gratings based on LabVIEW

Abstract

The present invention provides a LabVIEW-based fiber Bragg grating (FBG) multi-channel high-frequency signal acquisition method, which is applied to a fiber Bragg grating (FBG) multi-channel high-frequency signal acquisition system. The system includes a multi-channel fiber Bragg grating (FBG) sensing device and a host computer, which is equipped with a host computer data acquisition module and a data acquisition processing control module. The method includes: the data acquisition processing control module polls and opens the optical channels in the sensing device and sequentially acquires high-frequency data from the multi-channel fiber Bragg grating (FBG); the data acquisition processing control module stores the high-frequency data in a preset adjustable memory capacity buffer; when the number of elements stored in the adjustable memory capacity buffer exceeds the preset memory, the data in the adjustable memory capacity buffer is discharged and signal reassembly, filtering, component extraction, display, and storage are sequentially performed. This application improves the accuracy of multi-channel high-frequency signal acquisition by solving the problem of data acquisition time synchronization when the optical switch is polled and opened.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber Bragg grating high-frequency demodulation, and in particular to a fiber Bragg grating multi-channel high-frequency signal acquisition method based on LabVIEW. Background Art

[0002] Multi-point detection based on fiber Bragg grating (FBG) has been widely used in many fields such as engineering and scientific research. However, for scenarios such as multi-point vibration and impact detection based on fiber Bragg grating (FBG) that require high-frequency and rapid measurement, the existing mature demodulation systems and processing methods cannot meet the needs.

[0003] That is, how to provide a fiber Bragg grating multi-channel high-frequency signal acquisition method based on LabVIEW to achieve the technical effect of improving the accuracy of multi-channel high-frequency signal acquisition while realizing high-frequency and rapid acquisition is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] In view of the above problems, the present invention aims to provide a fiber Bragg grating multi-channel high-frequency signal acquisition method based on LabVIEW, which at least solves one of the above technical problems.

[0005] To at least solve the above technical problems, the present invention provides a LabVIEW-based fiber Bragg grating multi-channel high-frequency signal acquisition method, which is applied to a fiber Bragg grating multi-channel high-frequency signal acquisition system. The fiber Bragg grating multi-channel high-frequency signal acquisition system includes a multi-channel fiber Bragg grating sensing device and a host computer. The host computer is equipped with a host computer data acquisition module and a data acquisition processing control module. The method includes:

[0006] The data acquisition and processing control module polls and opens the optical channels in the multi-channel fiber Bragg grating sensing device according to a preset optical channel opening sequence, and sequentially obtains the high-frequency data of the multi-channel fiber Bragg grating acquired by the host computer data acquisition module according to a preset sampling rate;

[0007] The data acquisition and processing control module stores the sequentially acquired high-frequency data of the multi-channel fiber Bragg grating in a preset adjustable memory capacity buffer area and determines whether the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory of the adjustable memory capacity buffer area;

[0008] When the number of elements stored in the adjustable memory capacity buffer exceeds the preset memory, the data in the adjustable memory capacity buffer is flowed out and subjected to signal reorganization, filtering, component extraction, display and storage processing in sequence.

[0009] Preferably, the multi-channel fiber Bragg grating sensing device includes a tunable laser light source, a multi-channel fiber Bragg grating, an optical switch corresponding to the multi-channel fiber Bragg grating, and an optical performance detection module. The data acquisition and processing control module polls and opens the optical channels in the multi-channel fiber Bragg grating sensing device according to a preset optical channel opening sequence, and sequentially obtains high-frequency data of the multi-channel fiber Bragg grating acquired by the host computer data acquisition module according to a preset sampling rate, including:

[0010] The optical performance detection module is activated by the data acquisition and processing control module, and the optical performance detection module detects the optical spectrum of the fiber Bragg grating of the first channel according to a preset optical channel activation sequence, and the optical spectrum is processed according to a peak-finding algorithm to obtain the central wavelength of the fiber Bragg grating of the first channel;

[0011] Starting the tunable laser light source and determining whether the output wavelength of the tunable laser light source is within the current wavelength range of the first channel fiber Bragg grating 3dB bandwidth;

[0012] If not, compensating the output wavelength of the tunable laser light source according to the center wavelength of the first channel fiber Bragg grating until the output wavelength of the tunable laser light source is within the 3dB bandwidth wavelength range of the first channel fiber Bragg grating;

[0013] If yes, then turn on the optical switch corresponding to the first channel fiber Bragg grating, and obtain the high-frequency data of the first channel fiber Bragg grating by the host computer data acquisition module according to the preset sampling rate;

[0014] Determine whether the high-frequency data of the fiber Bragg grating of the first channel meets the preset acquisition conditions. If the high-frequency data of the fiber Bragg grating of the first channel meets the preset acquisition conditions, switch the optical switch to the fiber Bragg grating of the next channel according to the preset optical channel opening sequence and close the optical switch, and obtain the high-frequency data of the fiber Bragg grating of each channel in sequence according to the acquisition steps of the high-frequency data of the fiber Bragg grating of the first channel.

[0015] Preferably, the host computer data acquisition module includes an FPGA module and a Real-Time module, and sequentially acquiring high-frequency data of the multi-channel fiber Bragg grating acquired by the host computer data acquisition module according to a preset sampling rate includes:

[0016] The FPGA module sequentially collects high-frequency data of the multi-channel fiber Bragg grating according to a preset sampling rate, and stores the high-frequency data in the DMA FIFO;

[0017] The Real-Time module reads the high-frequency data in the DMA FIFO through the FIFO and writes the high-frequency data read from the FIFO into the network stream;

[0018] The data acquisition and processing control module reads the high-frequency data from the network stream.

[0019] Preferably, the FPGA module sequentially collects high-frequency data of the multi-channel fiber Bragg grating according to a preset sampling rate and stores the high-frequency data in a DMA FIFO, including:

[0020] The FPGA module first calls the reset I / O function, sets the STOP Boolean value to zero after the reset I / O function is called, and sends an interrupt code to the Real-Time module;

[0021] The FPGA module concurrently calls a generate I / O sampling pulse function to determine the sampling rate of the signal by the FPGA module, calls an obtain I / O status function to obtain the sample status of each channel, and calls a read I / O function to read high-frequency data from each channel;

[0022] When it is determined that the program status is correct, the high-frequency data is written into the DMA FIFO, and at the same time, it is determined whether an error code is generated in the program. If not, the high-frequency data is collected repeatedly.

[0023] Preferably, the preset memory of the adjustable memory capacity buffer area is M, and the expression of the preset memory is: ; Where n represents the number of data collected by the preset single channel; N is the number of optical switch channels;

[0024] Configure the number n of high-frequency data collected by the preset single channel according to the following formula: ; Where t represents the preset channel switching time, in ms; f represents the sampling rate preset by the FPGA module, in Hz.

[0025] Preferably, the preset acquisition condition is that the number of high-frequency data of the acquired single-channel fiber Bragg grating is greater than or equal to a preset number n of high-frequency data acquired by the single channel.

[0026] Preferably, the step of storing the sequentially acquired high-frequency data of the multi-channel fiber Bragg grating in a preset adjustable memory capacity buffer area through the data acquisition and processing control module and determining whether the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory capacity includes:

[0027] The data acquisition and processing control module continuously receives and acquires high-frequency data of the multi-channel fiber Bragg grating and introduces it as data elements in an orderly manner into the adjustable memory capacity buffer area constructed by the while loop statement;

[0028] Obtaining the initial number of data elements in the adjustable memory capacity buffer area and recording it in a shift register as an initial reference for subsequent counting operations;

[0029] For each new data element entering the while loop statement, the count value of the shift register is accumulated based on the initial benchmark until the count value in the shift register exceeds (is greater than and equal to) the preset memory M that is preset manually.

[0030] Preferably, when the number of elements stored in the adjustable memory capacity buffer exceeds the preset memory, the data in the adjustable memory capacity buffer is discharged and signal reassembly, filtering, component extraction, display and storage processing are performed in sequence, including:

[0031] When the count value in the shift register exceeds the preset memory M, the multi-channel high-frequency data cached in the adjustable memory capacity buffer area is streamed out;

[0032] performing signal recombining processing on the multi-channel high-frequency data flowing out of the adjustable memory capacity buffer area in sequence to obtain N high-frequency waveform signals;

[0033] The N high-frequency waveform signals are filtered respectively, and target data is extracted from the filtered high-frequency waveform signals, and the target data is displayed on an N-channel waveform chart. A data storage circulation system with an event state machine is constructed using a queue message processor mode, and the display data on the N-channel waveform chart is stored through the data storage circulation system.

[0034] Preferably, the signal recombining processing is performed on the multi-channel high-frequency data flowing out of the adjustable memory capacity buffer area in sequence to obtain N high-frequency waveform signals, including:

[0035] Converting the multi-channel high-frequency data flowing out of the adjustable memory capacity buffer area from U32 type to DBL type;

[0036] Then, the multi-channel high-frequency data after type conversion is divided into N groups of parallel array subsets according to specific rules, each array subset has n numbers;

[0037] Performing signal recombination processing on each of the N groups of array subsets to obtain N high-frequency waveform signals;

[0038] The signal reassembly process includes: using N groups of array subsets as Y and using the sampling rate f of the signal sampled by the FPGA module as dt to create a waveform.

[0039] Preferably, extracting target data from the filtered high-frequency waveform signal comprises:

[0040] The numerical data as Y in the high-frequency waveform signal is extracted from the filtered high-frequency waveform signal to obtain target data, and the data type of the target data is DBL type.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention provides a LabVIEW-based fiber Bragg grating (FBG) multi-channel high-frequency signal acquisition method, which is applied to a fiber Bragg grating (FBG) multi-channel high-frequency signal acquisition system. The system includes a multi-channel fiber Bragg grating (FBG) sensing device and a host computer. The host computer is equipped with a host computer data acquisition module and a data acquisition processing control module. The method specifically includes: the data acquisition processing control module polls and opens optical channels in the multi-channel fiber Bragg grating (FBG) sensing device according to a preset optical channel opening sequence, and sequentially acquires high-frequency data of the multi-channel fiber Bragg grating (FBG) acquired by the host computer data acquisition module according to a preset sampling rate; the data acquisition processing control module stores the sequentially acquired high-frequency data of the multi-channel fiber Bragg grating (FBG) in a preset adjustable memory capacity buffer area, and determines whether the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory of the adjustable memory capacity buffer area; when the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory, the data in the adjustable memory capacity buffer area is discharged and signal reorganization, filtering, component extraction, display, and storage processing are sequentially performed. The method provided in the present application solves the problem of asynchronous data collection time synchronization when the optical switch polling is turned on by setting an adjustable memory capacity buffer area to compensate for the synchronous time of asynchronously collected data. At the same time, by outflowing the data in the adjustable memory capacity buffer area and sequentially performing signal reorganization, filtering, component extraction, display and storage processing, the method eliminates the noise interference caused by low-frequency noise in the environment and multi-channel fiber grating sensing equipment, improves the signal-to-noise ratio of the collected high-frequency signal, and improves the accuracy of multi-channel high-frequency signal collection.

[0043] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1This is a flow chart of the fiber Bragg grating multi-channel high-frequency signal acquisition method provided by the present application;

[0046] Figure 2 This is a diagram of the optical path connection of the multi-channel fiber Bragg grating sensing device provided by this application;

[0047] Figure 3 This is a flowchart of the acquisition of fiber Bragg grating multi-channel high-frequency signals provided by this application;

[0048] Figure 4 This is a flowchart of the program for collecting high-frequency data using the FPGA module provided by this application;

[0049] Figure 5 This is the flowchart of the Real-Time module producer-consumer program provided by this application;

[0050] Figure 6 This is a control process flow chart of the data acquisition and processing control module provided by this application;

[0051] Figure 7 This is a schematic diagram of wavelength matching of a tunable laser light source provided by the present application under a large stress or variable temperature environment;

[0052] Figure 8 This is a workflow diagram of the adjustable memory capacity cache area provided by this application;

[0053] Figure 9 This is the data processing process of the adjustable memory capacity cache area provided by this application;

[0054] Figure 10 It is a signal reorganization flow chart provided by this application;

[0055] Figure 11 This is the high-frequency signal extraction flow chart provided by this application. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the embodiments described are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention; the "and / or" keywords involved in this implementation represent both and and or. In other words, A and / or B mentioned in the embodiments of this specification represent both A and B and A or B, and describe the three states of A and B. For example, A and / or B means: only A is included but not B; only B is included but not A; and both A and B are included.

[0057] Meanwhile, in the embodiments of this specification, when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component.

[0058] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0059] Example 1

[0060] See also Figure 1-10 Specifically, in an embodiment of the fiber Bragg grating multi-channel high-frequency signal acquisition method based on LabVIEW, the method is applied to a fiber Bragg grating multi-channel high-frequency signal acquisition system, which includes a multi-channel fiber Bragg grating sensing device and a host computer, wherein the host computer is equipped with a host computer data acquisition module and a data acquisition processing control module. The method specifically includes the following steps S110 to S130:

[0061] Step S110: the data acquisition and processing control module polls and opens the optical channels in the multi-channel fiber Bragg grating sensing device according to a preset optical channel opening sequence, and sequentially obtains the high-frequency data of the multi-channel fiber Bragg grating acquired by the host computer data acquisition module according to a preset sampling rate;

[0062] The LabVIEW development environment was deployed on the host computer. Both the host computer data acquisition module and the data acquisition, processing, and control module were built within this LabVIEW environment. This integrated environment enables the functional operation and collaborative work of each module, ensuring efficient and stable execution of data acquisition and processing control.

[0063] The FPGA Module is an expansion tool designed specifically for field-programmable gate array (FPGA) hardware. It allows users to implement high-performance parallel computing and real-time processing on FPGAs through graphical programming. The FPGA Module directly generates code for FPGA hardware, providing low-latency and high-throughput control and data processing capabilities. It supports parallel processing and can execute multiple tasks simultaneously, making it suitable for applications requiring high precision and efficiency, such as high-speed data acquisition, real-time control, and signal processing. The FPGA Module is compatible with other LabVIEW functional modules and can seamlessly integrate with NI data acquisition cards on hardware platforms such as CompactRIO and PXI, providing flexible and customized hardware solutions.

[0064] As an implementable method, the multi-channel fiber Bragg grating sensing device includes a tunable laser light source, a multi-channel fiber Bragg grating, an optical switch corresponding to the multi-channel fiber Bragg grating, and an optical performance detection module. The data acquisition and processing control module involved in the above step S110 polls and opens the optical channels in the multi-channel fiber Bragg grating sensing device according to a preset optical channel opening sequence, and sequentially obtains high-frequency data of the multi-channel fiber Bragg grating collected by the host computer data acquisition module according to a preset sampling rate. Specifically, the following contents are included:

[0065] The optical performance detection module is started by the data acquisition and processing control module, and the optical performance detection module detects the optical spectrum of the first channel fiber Bragg grating according to the preset optical channel opening sequence, and processes the optical spectrum according to the peak search algorithm to obtain the central wavelength of the first channel fiber Bragg grating;

[0066] Turn off the optical performance detection module, start the tunable laser light source, obtain the output wavelength of the tunable laser light source, and determine whether the output wavelength of the tunable laser light source is within the 3dB bandwidth wavelength range of the first channel fiber Bragg grating;

[0067] If the output wavelength of the tunable laser light source is not within the 3dB bandwidth wavelength range of the first channel fiber Bragg grating, the output wavelength of the tunable laser light source is compensated according to the center wavelength of the first channel fiber Bragg grating until the output wavelength of the tunable laser light source is within the 3dB bandwidth wavelength range of the first channel fiber Bragg grating;

[0068] If the output wavelength of the tunable laser light source is within the 3dB bandwidth wavelength range of the first channel fiber Bragg grating, the optical switch corresponding to the first channel fiber Bragg grating is turned on, and high-frequency data of the first channel fiber Bragg grating is acquired by the host computer data acquisition module according to a preset sampling rate;

[0069] Determine whether the high-frequency data of the fiber Bragg grating of the first channel meets the preset acquisition conditions. If the high-frequency data of the fiber Bragg grating of the first channel meets the preset acquisition conditions, turn off the tunable laser light source and switch the optical switch to the fiber Bragg grating of the next channel according to the preset optical channel opening sequence and turn off the optical switch. According to the acquisition steps of the high-frequency data of the fiber Bragg grating of the first channel, the high-frequency data of the fiber Bragg grating of each channel is acquired in sequence.

[0070] After the high-frequency data of the fiber Bragg grating of the first channel is acquired, the high-frequency data of the fiber Bragg grating of the second channel is acquired in sequence according to the acquisition steps of the high-frequency data of the fiber Bragg grating of the first channel until the high-frequency data of the fiber Bragg grating of the Nth channel is acquired, thereby completing a switching cycle. The high-frequency data of the fiber Bragg grating of the second channel is acquired in sequence according to the acquisition steps of the high-frequency data of the fiber Bragg grating of the first channel as follows:

[0071] The optical performance detection module is started by the data acquisition and processing control module, and the optical performance detection module detects the optical spectrum of the second channel fiber Bragg grating according to the preset optical channel opening sequence, and processes the optical spectrum according to the peak search algorithm to obtain the central wavelength of the second channel fiber Bragg grating;

[0072] Turn off the optical performance detection module, start the tunable laser light source, obtain the output wavelength of the tunable laser light source, and determine whether the output wavelength of the tunable laser light source is within the 3dB bandwidth wavelength range of the second channel fiber Bragg grating;

[0073] If the output wavelength of the tunable laser light source is not within the 3dB bandwidth wavelength range of the second channel fiber Bragg grating, the output wavelength of the tunable laser light source is compensated according to the center wavelength of the second channel fiber Bragg grating until the output wavelength of the tunable laser light source is within the 3dB bandwidth wavelength range of the second channel fiber Bragg grating;

[0074] If the output wavelength of the tunable laser light source is within the 3dB bandwidth wavelength range of the second channel fiber Bragg grating, the optical switch corresponding to the second channel fiber Bragg grating is turned on, and high-frequency data of the second channel fiber Bragg grating is acquired by the host computer data acquisition module according to a preset sampling rate;

[0075] Determine whether the high-frequency data of the fiber Bragg grating of the second channel meets the preset acquisition conditions. If the high-frequency data of the fiber Bragg grating of the second channel meets the preset acquisition conditions, turn off the tunable laser light source and switch the optical switch to the third channel fiber Bragg grating according to the preset optical channel opening sequence and turn off the optical switch. In this way, the high-frequency data of the fiber Bragg grating of each channel is obtained according to the optical channel opening sequence until the high-frequency data of the fiber Bragg grating of the Nth channel is obtained, and the data acquisition of one polling switch is completed.

[0076] The problem of wavelength matching feedback under high stress and large temperature variation environments is solved by the control logic of the optical switch and the optical performance detection module by the data acquisition and processing control module.

[0077] As a feasible manner, the preset acquisition condition is that the number of high-frequency data of the acquired single-channel fiber Bragg grating is greater than or equal to the preset number n of high-frequency data acquired by the single channel.

[0078] in, Figure 2The optical path connection diagram of the multi-channel fiber Bragg grating sensing device is shown. The multi-channel fiber Bragg grating sensing device specifically includes a tunable laser light source, an optical splitter, a multi-channel fiber Bragg grating, an optical switch corresponding to the multi-channel fiber Bragg grating, an optical performance detection module, and a photodetector. The tunable laser light source is used to output a first optical signal with adjustable wavelength; the optical splitter is used to split the first optical signal into multiple second optical signals; the multi-channel fiber Bragg grating (FGB1-FBGN) is used to detect the high-frequency signal according to the preset optical channel opening sequence under the action of the multiple second optical signals, and output multiple third optical signals, and multiple The initial center wavelengths of the channel fiber Bragg grating sensors are within the same wavelength range; the optical switch is used to switch the optical channels in the multi-channel fiber Bragg grating according to a preset optical channel opening sequence; the photodetector is used to convert multiple third optical signals into multiple voltage signals; the host computer data acquisition module can be integrated into the NI acquisition card to collect the voltage signals output by the photodetector, that is, the high-frequency data that needs to be collected in this application; the data acquisition and processing control module communicates with the tunable laser light source, the optical switch, the optical performance detection module and the host computer data acquisition module respectively to control channel switching and signal collection.

[0079] Step S120: storing the sequentially acquired high-frequency data of the multi-channel fiber Bragg grating in a preset adjustable memory capacity buffer area through the data acquisition and processing control module, and determining whether the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory of the adjustable memory capacity buffer area;

[0080] As a feasible approach, the host computer data acquisition module includes an FPGA module and a Real-Time module, and both the FPGA module and the Real-Time module can be integrated into the NI acquisition card.

[0081] Then, the step S120 mentioned above involves sequentially acquiring the high-frequency data of the multi-channel fiber Bragg grating acquired by the host computer data acquisition module according to the preset sampling rate, specifically including the following sub-steps (1) to (3):

[0082] (1) The FPGA module collects high-frequency data of multi-channel fiber Bragg gratings in sequence according to the preset sampling rate and stores the high-frequency data in the DMA FIFO;

[0083] As an achievable method, the FPGA module involved in the above sub-step (1) sequentially collects high-frequency data of the multi-channel fiber Bragg grating according to a preset sampling rate and stores the high-frequency data in a DMA FIFO, which specifically includes the following contents:

[0084] The FPGA module first calls the Reset I / O function. After the Reset I / O function completes, it resets the STOP Boolean value to zero and sends an interrupt code to the Real-Time module.

[0085] The FPGA module concurrently calls the Generate I / O Sample Pulse function to determine the sampling rate of the signal, calls the Get I / O Status function to obtain the sample status of each channel, and calls the Read I / O function to read high-frequency data from each channel.

[0086] When the program status is judged to be correct, the high-frequency data is written into the DMA FIFO. At the same time, it is judged whether the program has an error code. If not, the high-frequency data is collected repeatedly.

[0087] The program flow chart of the above FPGA module collecting high-frequency data can be found in the attached Figure 4 .

[0088] When writing the program, call the "Read I / O Function" and write to the DMA FIFO within a while loop. The "Read I / O Function" reads the data acquired by the NI acquisition and writes it to the shift register. The shift register acts as a buffer. With each iteration of the while loop, the shift register outputs the data entered during the previous iteration and transfers this data to the DMA FIFO. This programming design, which temporarily stores the data from the previous iteration and outputs it during the next iteration, allows each while loop iteration to complete quickly, keeping up with the NI acquisition card's maximum sampling rate of 1 MS / s.

[0089] (2) The Real-Time module reads the high-frequency data in the DMA FIFO through the FIFO and writes the high-frequency data read from the FIFO into the network stream;

[0090] The data from the above sub-step (1) is uploaded to the Real-Time module through the DMA-FIFO, and then processed by the Real-Time module. The FIFO read rate of the Real-Time module determines whether the DMA FIFO overflows.

[0091] In the Real-Time module design, the high-frequency data detected by the fiber Bragg grating sensor is uploaded to the Real-Time module through the DMA FIFO. The high-frequency data detected by the fiber Bragg grating sensor read from the FIFO is read and written into the network stream, and the two processes are separated.

[0092] When designing a Real-Time module program, if you place the program that reads FIFO data and the program that writes to a network stream in the same while loop, the program that reads FIFO data will run much faster than the program that writes to the network stream, causing overflow and loss of collected high-frequency data.

[0093] Therefore, if Figure 5 The flowchart of the Real-Time module producer-consumer program is shown. The producer-consumer framework is used to separate the two processes. The producer part handles the problem of transmitting high-frequency data from the FPGA module to the Real-Time module through the FIFO. The consumer part processes the fiber Bragg grating high-frequency data read from the upper part of the FIFO, first putting it into the queue buffer, and then reading the queue buffer data in the consumer part loop. Under the action of the buffer, the two loops can run at their respective iteration speeds without affecting each other, effectively solving the problem of FIFO data overflow.

[0094] (3) The data acquisition and processing control module reads high-frequency data from the network stream.

[0095] As an achievable method, the above-mentioned step S120 involves storing the high-frequency data of the multi-channel fiber Bragg grating acquired in sequence in a preset adjustable memory capacity buffer area through the data acquisition and processing control module and judging whether the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory, specifically including the following sub-steps (4) to (6):

[0096] (4) The data acquisition and processing control module continuously receives and acquires the high-frequency data of the multi-channel fiber Bragg grating and introduces it as data elements in an orderly manner into the adjustable memory capacity buffer area constructed by the while loop statement;

[0097] As a feasible method, the preset memory of the adjustable memory capacity cache is M. This preset memory M can be pre-set and adjusted according to the actual application scenario and system resource status to ensure the stability and effectiveness of the system during data processing. The expression of the preset memory is: ; Where n represents the number of data collected by the preset single channel; N is the number of optical switch channels;

[0098] Configure the number n of high-frequency data collected by the preset single channel according to the following formula: ; Where t represents the preset channel switching time, in ms; f represents the sampling rate preset by the FPGA module, in Hz.

[0099] (5) Obtaining the initial number of data elements in the adjustable memory capacity buffer and recording it in the shift register as the initial reference for subsequent counting operations;

[0100] (6) For each new data element that enters the while loop statement, the count value of the shift register is accumulated based on the initial benchmark until the count value in the shift register reaches or exceeds the preset memory M.

[0101] As an example, Figure 8 A more detailed understanding of the workflow diagram of the adjustable memory capacity cache area.

[0102] Figure 6 The data acquisition and processing control module controls the multi-channel fiber Bragg grating sensor device and processes the high-frequency signal. Specifically, the data acquisition and processing control module of the host computer first turns on the optical performance detection module to detect the optical performance of the optical fiber Bragg grating sensor device. Figure 6 The spectrum of the FBG1 channel fiber Bragg grating sensor in the figure is shown in Figure 1. The central wavelength of FBG1 is obtained by the peak-finding algorithm. When encountering large stress or large temperature changes, such as Figure 7 The diagram shows the wavelength matching of the tunable laser light source under high stress or variable temperature environment. The center wavelength of the spectrum detected by the optical performance detection module shifts to deviate from the set 3dB bandwidth range. At this time, the output wavelength of the wavelength tunable laser light source obtained by the spectrum peak search of the optical performance detection module can be compensated so that it is located near the 3dB bandwidth wavelength of the multi-channel fiber Bragg grating. Then, the FBG1 channel of the optical switch is turned on to collect high-frequency data transmitted from the Real-Time module through the network stream, and determine whether the number of data collected when the optical switch is in the open state is n. If so, the collected n data are stored in a preset adjustable memory capacity buffer area. The preset memory of the adjustable memory capacity buffer area is M. Then, the optical switch is switched to Figure 1 The FBG2 channel is switched off and the optical switch is turned off. The optical performance detection module is then turned on again to detect the spectrum of the FBG2 channel. The above steps are repeated in sequence. When the optical switch automatically polls and switches once, the number of elements in the buffer area of ​​the memory capacity can be adjusted to ≥ M. The array data in the buffer area is then streamed out for signal reassembly, filtering, component extraction, display, and storage processing. The buffer area is reset to wait for the next round of array data to flow in, and the above steps are repeated.

[0103] Step S130: When the number of elements stored in the adjustable memory capacity buffer exceeds the preset memory, the data in the adjustable memory capacity buffer is flowed out and subjected to signal reorganization, filtering, component extraction, display and storage processing in sequence.

[0104] As an achievable method, the above-mentioned step S130 involves, when the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory, flowing out the data in the adjustable memory capacity buffer area and sequentially performing signal reorganization, filtering, component extraction, display and storage processing, specifically including the following sub-steps (7) to (9):

[0105] (7) When the count value in the shift register exceeds the preset memory M, the multi-channel high-frequency data cached in the adjustable memory capacity buffer area is streamed out;

[0106] (8) performing signal recombining processing on the multi-channel high-frequency data flowing out of the adjustable memory capacity buffer area in sequence to obtain N high-frequency waveform signals;

[0107] As a feasible way, Figure 9 As shown, the above sub-step (8) involves sequentially performing signal recombining processing on the multi-channel high-frequency data flowing out of the adjustable memory capacity buffer area to obtain N high-frequency waveform signals, which specifically includes the following contents:

[0108] Convert the multi-channel high-frequency data flowing out of the adjustable memory capacity buffer area from U32 type to DBL type;

[0109] Then, the multi-channel high-frequency data after type conversion is divided into N groups of parallel array subsets according to specific rules, and each array subset has n numbers;

[0110] Performing signal recombination processing on each of the N groups of array subsets to obtain N high-frequency waveform signals;

[0111] in, Figure 10 A signal reassembly flow chart is shown, and the corresponding signal reassembly processing includes: using N groups of array subsets as Y and the sampling rate f at which the FPGA module samples the signal as dt to create a waveform.

[0112] Specifically, the multi-channel high-frequency data flowing out of the adjustable memory capacity buffer is converted from U32 type to DBL type. The data flowing out of the buffer is divided into N groups of array subsets, each array subset has n numbers, and each group of array subsets is parallel. A waveform is created through LabVIEW, and the N groups of array subsets are used as Y and the sampling rate f of the FPGA module is used as dt to convert it into a high-frequency signal.

[0113] (9) Filter the N high-frequency waveform signals separately, extract the target data from the filtered high-frequency waveform signals, and display the target data on the N-channel waveform chart. Use the queue message processor mode to build a data storage loop system with an event state machine, and store the display data on the N-channel waveform chart through the data storage loop system.

[0114] As a feasible way, Figure 11 As shown, the above sub-step (9) involves extracting target data from the filtered high-frequency waveform signal, specifically including the following contents:

[0115] The numerical data as Y in the high-frequency waveform signal is extracted from the filtered high-frequency waveform signal to obtain target data, and the data type of the target data is DBL type.

[0116] The created high-frequency waveform signal is fed into the Digital IIR Filter function Vi for high-pass filtering to eliminate low-frequency noise. The filtered N-channel high-frequency waveform signal is fed into the FFT Spectrum (Mag-Phase) function Vi written in LabVIEW. A frequency domain plot of the N-channel high-frequency signal is generated through transformation and peak-finding algorithms. This plot is then used to determine the validity of the signal. The filtered high-frequency signal is then subjected to waveform component extraction, extracting the numerical data represented by Y within the signal and retrieving the filtered DBL-type numerical data. The obtained numerical data is displayed on an N-channel waveform chart. Using the Queue Message Handler (QMH) design mode, a data storage loop with its own event state machine is established to store the displayed data on the N-channel waveform chart.

[0117] From the overall perspective, Figure 3 The overall acquisition process of fiber Bragg grating multi-channel high-frequency signals and some of the corresponding functions implemented by the data acquisition and processing control module of the host computer are shown, including feedback control of the tunable laser light source, optical switch switching setting, optical channel opening sequence, optical performance detection module control, acquisition card (acquisition card integrated with the host computer data acquisition module) parameter setting (sampling rate), multi-channel spectrum display, filter parameter setting, high-frequency data caching, and storage of high-frequency waveform signals and target signals.

[0118] In summary, the present invention provides a LabVIEW-based fiber Bragg grating multi-channel high-frequency signal acquisition method, which is applied to a fiber Bragg grating multi-channel high-frequency signal acquisition system. The system includes a multi-channel fiber Bragg grating sensing device and a host computer. The host computer is equipped with a host computer data acquisition module and a data acquisition processing control module. The method specifically includes: the data acquisition processing control module polls and opens the optical channels in the multi-channel fiber Bragg grating sensing device according to a preset optical channel opening sequence, and sequentially obtains the high-frequency data of the multi-channel fiber Bragg grating obtained by the host computer data acquisition module according to a preset sampling rate; the data acquisition processing control module stores the sequentially obtained high-frequency data of the multi-channel fiber Bragg grating in a preset adjustable memory capacity buffer area and determines whether the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory of the adjustable memory capacity buffer area; when the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory, the data in the adjustable memory capacity buffer area is discharged and signal reorganization, filtering, component extraction, display and storage processing are sequentially performed. The method provided in the present application solves the problem of asynchronous data collection time synchronization when the optical switch polling is turned on by setting an adjustable memory capacity buffer area to compensate for the synchronous time of asynchronously collected data. At the same time, by outflowing the data in the adjustable memory capacity buffer area and sequentially performing signal reorganization, filtering, component extraction, display and storage processing, the interference of low-frequency noise in the environment, tunable laser light source noise and low-frequency noise caused by dark current in the photodetector is eliminated, the signal-to-noise ratio of the collected high-frequency signal is improved, and the accuracy of multi-channel high-frequency signal collection is improved.

[0119] The technical features in the claims of this application are based on the text description. The drawings are used to assist in understanding the concept and embodiments of the present invention, and the text description should be used as the basis for determining the scope of protection of the present invention.

[0120] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for understanding and reading by those familiar with this technology, and are not used to limit the conditions for implementation of the present invention. Therefore, they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0121] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A fiber Bragg grating multi-channel high-frequency signal acquisition method based on LabVIEW, applied to a fiber Bragg grating multi-channel high-frequency signal acquisition system, characterized in that: The fiber Bragg grating multi-channel high-frequency signal acquisition system includes a multi-channel fiber Bragg grating sensing device and a host computer, wherein the host computer is equipped with a host computer data acquisition module and a data acquisition processing control module. The method includes: The data acquisition and processing control module polls and opens the optical channels in the multi-channel fiber Bragg grating sensing device according to a preset optical channel opening sequence, and sequentially obtains the high-frequency data of the multi-channel fiber Bragg grating acquired by the host computer data acquisition module according to a preset sampling rate; The data acquisition and processing control module stores the sequentially acquired high-frequency data of the multi-channel fiber Bragg grating in a preset adjustable memory capacity buffer area and determines whether the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory of the adjustable memory capacity buffer area; When the number of elements stored in the adjustable memory capacity buffer exceeds the preset memory, the data in the adjustable memory capacity buffer is discharged and subjected to signal reassembly, filtering, component extraction, display and storage processing in sequence; The data acquisition and processing control module stores the high-frequency data of the multi-channel fiber Bragg grating acquired in sequence in a preset adjustable memory capacity buffer area and determines whether the number of elements stored in the adjustable memory capacity buffer area exceeds the preset memory, including: The data acquisition and processing control module continuously receives and acquires high-frequency data of the multi-channel fiber Bragg grating and introduces it as data elements in an orderly manner into the adjustable memory capacity buffer area constructed by the while loop statement; Obtaining the initial number of data elements in the adjustable memory capacity buffer area and recording it in a shift register as an initial reference for subsequent counting operations; For each new data element entering the while loop statement, the count value of the shift register is accumulated based on the initial benchmark until the count value in the shift register reaches or exceeds the preset memory M preset by humans.

2. The LabVIEW-based fiber Bragg grating multi-channel high-frequency signal acquisition method according to claim 1, wherein: The multi-channel fiber Bragg grating sensing device includes a tunable laser light source, a multi-channel fiber Bragg grating, an optical switch corresponding to the multi-channel fiber Bragg grating, and an optical performance detection module. The data acquisition and processing control module polls and opens the optical channels in the multi-channel fiber Bragg grating sensing device according to a preset optical channel opening sequence, and sequentially obtains high-frequency data of the multi-channel fiber Bragg grating acquired by the host computer data acquisition module according to a preset sampling rate, including: The optical performance detection module is activated by the data acquisition and processing control module, and the optical performance detection module detects the optical spectrum of the fiber Bragg grating of the first channel according to a preset optical channel activation sequence, and the optical spectrum is processed according to a peak-finding algorithm to obtain the central wavelength of the fiber Bragg grating of the first channel; Turning off the optical performance detection module, starting the tunable laser light source, and determining whether the output wavelength of the tunable laser light source is within the current 3dB bandwidth wavelength range of the first channel fiber Bragg grating; If the output wavelength of the tunable laser light source is not within the 3dB bandwidth wavelength range of the first channel fiber Bragg grating, compensating the output wavelength of the tunable laser light source according to the center wavelength of the first channel fiber Bragg grating until the output wavelength of the tunable laser light source is within the 3dB bandwidth wavelength range of the first channel fiber Bragg grating; If the output wavelength of the tunable laser light source is within the 3dB bandwidth wavelength range of the first channel fiber Bragg grating, the optical switch corresponding to the first channel fiber Bragg grating is turned on, and high-frequency data of the first channel fiber Bragg grating is acquired by a host computer data acquisition module according to a preset sampling rate; Determine whether the high-frequency data of the fiber Bragg grating of the first channel meets the preset acquisition conditions. If the high-frequency data of the fiber Bragg grating of the first channel meets the preset acquisition conditions, turn off the tunable laser light source and switch the optical switch to the fiber Bragg grating of the next channel according to the preset optical channel opening sequence and turn off the optical switch. According to the acquisition steps of the high-frequency data of the fiber Bragg grating of the first channel, the high-frequency data of the fiber Bragg grating of each channel is acquired in sequence.

3. The LabVIEW-based fiber Bragg grating multi-channel high-frequency signal acquisition method according to claim 1, wherein: The host computer data acquisition module includes an FPGA module and a Real-Time module, and sequentially acquiring high-frequency data of the multi-channel fiber Bragg grating acquired by the host computer data acquisition module according to a preset sampling rate includes: The FPGA module sequentially collects high-frequency data of the multi-channel fiber Bragg grating according to a preset sampling rate, and stores the high-frequency data in the DMAFIFO; The Real-Time module reads the high-frequency data in the DMA FIFO through the FIFO and writes the high-frequency data read from the FIFO into the network stream; The data acquisition and processing control module reads the high-frequency data from the network stream.

4. The LabVIEW-based fiber Bragg grating multi-channel high-frequency signal acquisition method according to claim 3, wherein: The FPGA module sequentially collects high-frequency data of the multi-channel fiber Bragg grating according to a preset sampling rate and stores the high-frequency data in the DMAFIFO, including: The FPGA module first calls the reset I / O function, sets the STOP Boolean value to zero after the reset I / O function is called, and sends an interrupt code to the Real-Time module; The FPGA module concurrently calls a generate I / O sampling pulse function to determine the sampling rate of the signal by the FPGA module, calls an obtain I / O status function to obtain the sample status of each channel, and calls a read I / O function to read high-frequency data from each channel; When it is determined that the program status is correct, the high-frequency data is written into the DMAFIFO, and at the same time, it is determined whether an error code is generated in the program. If not, the high-frequency data is collected in a repeated cycle.

5. The LabVIEW-based fiber Bragg grating multi-channel high-frequency signal acquisition method according to claim 1, wherein: The preset memory of the adjustable memory capacity buffer is M, and the expression of the preset memory is: M=nN; wherein n represents the number of data collected by the preset single channel; N is the number of optical switch channels; The number n of high-frequency data collected by the preset single channel is configured according to the following formula: n = 1000tf; where t represents the preset channel switching time in milliseconds; and f represents the sampling rate preset by the FPGA module in Hz.

6. The LabVIEW-based fiber Bragg grating multi-channel high-frequency signal acquisition method according to claim 2, wherein: The preset acquisition condition is that the number of high-frequency data of the acquired single-channel fiber Bragg grating is greater than or equal to the preset number n of high-frequency data acquired by the single channel.

7. The method for acquiring multi-channel high-frequency signals of fiber Bragg gratings based on LabVIEW according to claim 1, wherein: When the number of elements stored in the adjustable memory capacity buffer exceeds the preset memory, the data in the adjustable memory capacity buffer is discharged and signal reorganization, filtering, component extraction, display and storage processing are performed in sequence, including: When the count value in the shift register exceeds the preset memory M, the multi-channel high-frequency data cached in the adjustable memory capacity buffer area is streamed out; performing signal recombining processing on the multi-channel high-frequency data flowing out of the adjustable memory capacity buffer area in sequence to obtain N high-frequency waveform signals; The N high-frequency waveform signals are filtered respectively, and target data is extracted from the filtered high-frequency waveform signals, and the target data is displayed on an N-channel waveform chart. A data storage circulation system with an event state machine is constructed using a queue message processor mode, and the display data on the N-channel waveform chart is stored through the data storage circulation system.

8. The LabVIEW-based fiber Bragg grating multi-channel high-frequency signal acquisition method according to claim 7, wherein: The signal recombining process is performed on the multi-channel high-frequency data flowing out of the adjustable memory capacity buffer area in sequence to obtain N high-frequency waveform signals, including: Converting the multi-channel high-frequency data flowing out of the adjustable memory capacity buffer area from U32 type to DBL type; Then, the multi-channel high-frequency data after type conversion is divided into N groups of parallel array subsets according to specific rules, each array subset has n numbers; Performing signal recombination processing on each of the N groups of array subsets to obtain N high-frequency waveform signals; The signal reassembly process includes: using N groups of array subsets as Y and using the sampling rate f of the signal sampled by the FPGA module as dt to create a waveform.

9. The LabVIEW-based fiber Bragg grating multi-channel high-frequency signal acquisition method according to claim 8, wherein: The step of extracting target data from the filtered high-frequency waveform signal comprises: The numerical data as Y in the high-frequency waveform signal is extracted from the filtered high-frequency waveform signal to obtain target data, and the data type of the target data is DBL type.

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