Method for checking reliability of signal acquisition channel in rapidly changing measurement system based on lms acquisition device

Abstract

The application relates to a reliability checking method of an electrical equipment, in particular to a reliability checking method of a plug-in connector in a rapid change measurement system based on an LMS acquisition equipment, aiming at solving the problems of time-consuming, laborious, heavy workload and easy damage to the plug-in connector in the existing manual checking method of the reliability of the plug-in connector. The application comprises the following steps: 1, preparing and starting a first digital signal generator and a second digital signal generator; 2, connecting the input end of a first lead wire with the output end of the first digital signal generator; 3, starting and initializing acquisition software in an upper computer; 4, arranging the first signal and the second signal collected by the LMS acquisition equipment in step 3; 5, processing and analyzing the data by data processing software to obtain characteristic information of the first signal and the second signal; 6, comparing the characteristic information of the first signal and the second signal to judge whether the deviation of the characteristic information of the first signal and the second signal is within a preset reasonable range.

Description

TECHNICAL FIELD

[0001] The present application relates to a reliability checking method of an electrical device, in particular to a reliability checking method of a signal acquisition path in a speed change measurement system based on LMS acquisition equipment. BACKGROUND

[0002] The measurement schematic diagram of the existing speed change measurement system based on LMS acquisition equipment is shown in Figure 1 The connector is an indispensable adapter component in the measurement system, but the frequent plugging and unplugging in the long-term use process can easily lead to the reduction of the reliability of the connector. The reduction of the reliability mainly includes the following reasons: 1) after the connection of the pearl plug is plugged and unplugged for many times, the gap between the pin and the hole becomes large, which can easily cause poor contact and the falling of the plug or the socket; 2) due to the long-term use of the adapter cabinet, the working environment of the test bench is poor, such as strong speed change, strong corrosion or strong oxidation environment, and occasionally dry powder is used for fire-fighting work, which can easily lead to the reduction of the insulation of the measurement system; 3) the service life of the adapter cabinet, the line and the connector is long, and there are factors such as line aging and reliability reduction; 4) when the sensor or the plug is welded, occasional false welding can cause safety hazards to the measurement.

[0003] The existing reliability checking method of the connector is usually manual checking, mainly including the steps of opening the plug and observing whether the pin and the welding point exist oxidation and damage, etc. This method is time-consuming and laborious, and has large workload, and the frequent opening and wrapping of the connector can easily cause slight damage to the pin and the lead wire of the connector, which can easily reduce the reliability of the connector over a long period of time. SUMMARY

[0004] The purpose of the present application is to solve the problems of time-consuming and laborious, large workload and easy damage to the connector in the existing manual checking method of the reliability of the connector, and to provide a reliability checking method of a signal acquisition path in a speed change measurement system based on LMS acquisition equipment.

[0005] To achieve the above purpose, the technical solution provided by the present application is:

[0006] A reliability checking method of a signal acquisition channel in a rapid change measurement system based on an LMS acquisition device, the rapid change measurement system based on the LMS acquisition device comprising an adapter, a front interval adapter cabinet, an LMS acquisition device and an upper computer, an input end of the adapter being connected with a rocket engine through a first lead line, an output end of the adapter being connected with an input end of the front interval adapter cabinet through a movable cable, an output end of the front interval adapter cabinet being connected with a first input end of the LMS acquisition device through a long-range main cable, the LMS acquisition device being connected with the upper computer through a network cable; the signal acquisition channel comprising the first lead line, the adapter, the movable cable, the adapter cabinet and the long-range main cable; both ends of the first lead line, the movable cable and the long-range main cable are provided with connectors; the method comprises the following steps:

[0007] Step 1, preparing a first digital signal generator and a second digital signal generator and starting, so that the first digital signal generator and the second digital signal generator generate the same detection waveform signal, which is a first signal and a second signal respectively, and waiting until the first signal and the second signal are stable;

[0008] Step 2, taking the first lead line off the device to be measured, and connecting the output end of the first digital signal generator and the output end of the second digital signal generator with the first lead line and the second lead line respectively;

[0009] Step 3, sending a command to the upper computer to make the LMS acquisition device start collecting the first signal and the second signal, and when a first preset condition is met, the LMS acquisition device completes and stops collecting;

[0010] Step 4, sending the first signal and the second signal collected by the LMS acquisition device in step 3 to the upper computer, generating result data after processing, and arranging the result data;

[0011] Step 5, processing and analyzing the result data by the upper computer to obtain characteristic information of the first signal and the second signal;

[0012] Step 6, comparing the characteristic information of the first signal and the second signal, setting a preset reasonable range, if the deviation of the characteristic information of the first signal and the second signal is within the preset reasonable range, it is determined that the connection of all connectors in the rapid change measurement system based on the LMS acquisition device is reliable, and the reliability checking is completed, if the deviation of the characteristic information of the first signal and the second signal is not within the preset reasonable range, changing the connection position of the first digital signal generator in the signal acquisition channel and repeating steps 3-5 to determine the fault position.

[0013] Further, in step 1, the detection waveform is a sine function, the frequency f=10 kHz, the amplitude A=5 V, and the initial phase

[0014] Further, the first preset condition in step 3 is specifically: reaching a preset collection time length t or a preset sampling point number N, t≥300s, N≥6×10 5 .

[0015] Further, the result data in step 4 is stored in a *.txt format; and the “sorting result data” is specifically converting the result data from the *.txt format to a *.unv format.

[0016] Further, the feature information in step 5 includes a spectrum shape, a peak position and an amplitude size.

[0017] Further, in step 6, the preset reasonable range is specifically: a spectrum shape similarity of two signals≥80%, a phase value deviation percentage of a peak≤5%, and an amplitude size deviation percentage≤10%.

[0018] Further, in step 6, the changing of the connection position of the first digital signal generator and the repeated execution of steps 3-5 are specifically:

[0019] α) taking off the first lead from the output end of the first digital signal generator, taking off the active cable from the output end of the adapter and connecting the active cable to the output end of the first digital signal generator, executing steps 3-5 in turn, and comparing the feature information of the first signal and the second signal; if the deviation of the feature information of the first signal and the second signal is within the preset reasonable range, it is determined that the fault is located on the first lead or the adapter, and step β1) is executed; if the deviation of the feature information of the first signal and the second signal is not within the preset reasonable range, step β2) is executed;

[0020] β1) replacing a new first lead, then connecting the output end of the first digital signal generator to the input end of the first lead, executing steps 3-5 in turn, and comparing the feature information of the first signal and the second signal; if the deviation of the feature information of the first signal and the second signal is within the preset reasonable range, it is determined that the fault is located on the first lead; if the deviation of the feature information of the first signal and the second signal is not within the preset reasonable range, it is determined that the fault is located on the adapter; and the reliability check is completed;

[0021] β2) replacing a new active cable, then connecting the active cable to the output end of the first digital signal generator, executing steps 3-5 in turn, and comparing the feature information of the first signal and the second signal; if the deviation of the feature information of the first signal and the second signal is within the preset reasonable range, it is determined that the fault is located on the active cable, and the reliability check is completed; if the deviation of the feature information of the first signal and the second signal is not within the preset reasonable range, step γ) is executed;

[0022] g) disconnecting the long-range main cable from the output end of the front interval transfer cabinet and connecting to the output end of the first digital signal generator, and comparing the characteristic information of the first signal and the second signal after sequentially performing steps 3-5; if the deviation of the characteristic information of the first signal and the second signal is within the preset reasonable range, it is determined that the fault is located on the front interval transfer cabinet; if the deviation of the characteristic information of the first signal and the second signal is not within the preset reasonable range, it is determined that the fault is located on the long-range main cable; and completing the reliability check.

[0023] Further, step 5 is specifically:

[0024] Step 5.1, dividing the first signal and the second signal into equal time periods;

[0025] Step 5.2, analyzing the first signal and the second signal in each time period in the navigator module of the LMS data processing software, respectively, to obtain the average spectrum, the color spectrum and the slice graph of the first signal and the second signal;

[0026] Step 5.3, obtaining the frequency spectrum shape, peak position and amplitude size data of the first signal and the second signal by using the obtained average spectrum, color spectrum and slice graph.

[0027] Compared with the prior art, the beneficial effects of the present application are:

[0028] 1. The reliability check method of the signal acquisition channel in the fast change measurement system based on the LMS acquisition device provided by the present application uses the characteristic information of the first signal and the second signal to judge the reliability of the signal acquisition channel, avoiding the complex and time-consuming operation of opening the plug to observe the pin and the welding point in the traditional method; the traditional method needs to manually open the connector one by one and carefully check the condition of each pin and welding point, which not only has a huge workload, but also is easily affected by human factors such as the vision and experience of the inspector; while the present application only needs to generate a specific signal through two programmable digital signal generators, collect and analyze the spectrum by the LMS acquisition system, and then compare the spectrum characteristics, so the operation process is relatively simple and clear, and easy for technicians to master and implement; in the whole detection process, from the setting of the digital signal generator, the signal output connection to the acquisition channel configuration, the signal acquisition and processing steps, there are clear operation specifications and processes. For example, in the digital signal generator starting and waveform generating step, only the specific waveform needs to be generated according to the characteristics of the fast change measurement system and the detection requirements of the signal acquisition channel, without the need for complex detection tools and additional manual judgment, which greatly reduces the operation difficulty and improves the detection efficiency.

[0029] 2、The reliability checking method of the signal acquisition channel in the rapid change measurement system based on the LMS acquisition equipment provided by the application, from a theoretical basis, the connector and the cable can be equivalent to a mathematical model composed of resistance and capacitance, and the changes of the line capacitance and resistance will affect the line frequency components; when the connector has a problem, the signal spectrum will change obviously, such as sudden frequency change disorder, increase of sudden frequency components, etc.; the application is based on this theory, and the connector reliability is judged by analyzing the spectrum characteristics, which has a solid theoretical basis and is more scientific than the traditional method which only relies on appearance inspection.

[0030] 3、The reliability checking method of the signal acquisition channel in the rapid change measurement system based on the LMS acquisition equipment provided by the application, in practice, the application can quantitatively select a more reliable measurement channel by comparing and analyzing the line spectrum data and the channel correlation through self-programming algorithm design of the waveform containing multi-frequency band characteristics; for example, in the data processing process, the data collected in different time periods are analyzed in multiple dimensions, including time domain amplitude range, deviation, drift determination and spectrum analysis, etc., various factors are considered comprehensively, the limitations of single factor judgment are avoided, and whether the connector has an abnormality is determined more accurately, so that the reliability of the detection result is effectively improved, and a powerful guarantee is provided for the stable operation of the rapid change measurement system. The method is compared with the spectrum analysis result directly added to the input end of the LMS acquisition equipment by the signal generator, so that the accuracy of the judgment is further ensured, and the detection result is more reliable; through the comparison, the interference of other factors in the signal transmission process can be excluded, and the reliability of the connector itself can be accurately judged. If there is no such comparison, the problems in the signal transmission line may be misjudged as connector problems, or vice versa, so that the accurate diagnosis and repair of the system fault are affected.

[0031] 4、The reliability checking method of the signal acquisition channel in the rapid change measurement system based on the LMS acquisition equipment provided by the application, accurate detection of the connector reliability is helpful for timely discovery of potential problems and avoidance of measurement data abnormality or system shutdown caused by connector failure. In the field of aerospace and other fields with extremely high reliability requirements, the stable operation of the rapid change measurement system is very important, and any slight failure may cause serious consequences. The patent technology can effectively improve the accuracy and reliability of the connector detection, so as to ensure the stable operation of the entire rapid change measurement system, ensure the accuracy and reliability of the test data, and provide solid data support for the research and development and test of aerospace engines and other equipment. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a measurement schematic diagram of the existing rapid change measurement system based on the LMS acquisition equipment;

[0033] Figure 2 It is a flowchart of the embodiment of the application, and the orange box is the signal acquisition channel.

[0034] Figure 3 To measure the equivalent schematic diagram of the cable on the circuit;

[0035] Explanation of reference signs:

[0036] 1 - first digital signal generator; 2 - first lead; 3 - adapter; 4 - active cable; 5 - adapter cabinet; 6 - long-range main cable; 7 - second digital signal generator; 8 - second lead; 9 - LMS acquisition device; 10 - network cable; 11 - upper computer; 12 - rocket engine; 121 - vibration sensor; 122 - vibration measuring block. DETAILED DESCRIPTION

[0037] As Figure 1 shown is a measurement schematic diagram of an existing fast change measurement system based on an LMS acquisition device. From the entire measurement system, any abnormal measurement link will inevitably lead to abnormal measurement data. For singular signal data in the data, the commonly used analysis method is to use the traditional extreme value analysis method, that is, to judge whether the measured data is a singular point by whether the absolute value of the measured data minus a given value is within a given range. This is because the mutation part and singular point and other irregular parts in the signal usually contain important information. The singularity of the signal contains two meanings: (1) the amplitude of the signal changes suddenly at a certain time, causing the signal to be discontinuous; (2) the signal is very smooth in appearance, and the amplitude does not change suddenly, but the first derivative of the signal has a sudden change and the first derivative is discontinuous. For fast-changing signals with fast signal changes and wide signal frequency bands, the commonly used analysis method is to perform Fourier analysis on a certain time interval, and to judge whether it is abnormal and whether there is singularity in the signal in the interval segment by the speed of spectral attenuation or the number of sudden frequency components.

[0038] One of the criteria for determining the cause of data anomalies is to use correlation analysis methods to analyze and compare the remaining parameter data related to this parameter in the entire test process, thereby determining the cause of the data anomaly. Another method of discrimination is to compare and analyze the test data of the same type from the past to draw conclusions about the cause of the signal anomaly. In theory, regardless of the cause of the signal anomaly, the mathematical mechanism pattern of the signal anomaly has great similarity in essence. The pattern of data signal anomaly mainly includes the following four types: signal deviation anomaly, signal drift problem, signal accuracy level reduction, and signal complete failure. Deviation anomaly mainly refers to a type of fault in which the abnormal measurement value differs from the correct measurement value by a certain constant.

[0039] That is:

[0040] x e = k (1)

[0041] Where k is a constant.

[0042] Drift problems refer to a class of faults in which the magnitude of the fault changes linearly with time, and their representation is as follows:

[0043] x e =h(tt) f (2)

[0044] Among them, t f t represents the start time of the fault; t represents any time after the fault occurs; h is a constant.

[0045] This type of fault manifests as the measured value increasing continuously over time.

[0046] Deviation and drift faults manifest as deviations in the average measurement value. When the accuracy level is reduced, the average measurement value remains unchanged; instead, the variance of the measurement changes. Specifically, this is expressed as:

[0047]

[0048] In the formula To measure the change in variance, N represents a normal distribution.

[0049] because According to probability theory, the sum of two normal distributions is still a normal distribution, therefore:

[0050]

[0051] As can be seen from the formula, this type of fault is similar to free noise. Similar to the increase in variance of free noise, it will cause faulty measurements and fault-free measurements to be mixed together.

[0052] In a complete failure, the measured value does not change with actual changes and remains at a certain reading. This constant value is usually zero or the maximum reading. This type of failure can be represented as:

[0053] x t =c (5)

[0054] Where, x e For drift fault, x z It is a variable related to the change in measurement variance, x t It is a variable that comprehensively considers drift faults and changes in measurement variance, x f These are fault measurements. The variables mentioned above are mainly used to describe fault measurements and their related statistical characteristics, especially when considering drift faults and changes in measurement variance.

[0055] The above mode is only analyzed from the time domain, but the rapid change signal is a random signal, and it is not scientific to analyze it only from the time domain. Therefore, the fault signal needs to be analyzed in depth from the frequency domain. In theory, when the rapid change measurement system connector is in good condition, the frequency spectrum of the measurement data has certain significant characteristics. When the measurement system connector has a problem, the signal spectrum will also change significantly. Therefore, the time domain and frequency domain changes of the rapid change signal are the basis for connector diagnosis. Time domain analysis is to study the law of signal form change with time, and to extract necessary characteristic quantities (such as amplitude, period, local rise time and fall time) as the basis for signal judgment and recognition. Frequency domain analysis is to study the law of signal energy or power change with time, thereby providing a basis and means for further processing of the signal. The frequency domain analysis of the signal is more intuitive and convenient than the time domain waveform analysis. In order to identify the connector fault signal, the signal recorded on site needs to be properly processed, and the fault signal is identified in the processing result to determine the fault position and fault degree.

[0056] In view of the LMS acquisition system currently used, it provides the following convenient conditions for the connector fault diagnosis scheme:

[0057] (1) Since the LMS acquisition system itself integrates a charge amplifier, the existing rapid change measurement system front and rear channels can be one-to-one corresponding, which replaces the original discrete charge amplifier which is often replaced each time, resulting in inconsistent state of each measurement channel, and the consistency of the measured data cannot be compared;

[0058] (2) The LMS acquisition system records all rapid change parameters, without adding any additional instrument, which maximizes the reduction of the influence of the uncertainty of the rapid change measurement system, and is beneficial to the multiple comparison of the measurement signal.

[0059] In order to improve the overall reliability of the rapid change measurement system, and combined with the need for digital measurement, the following connector reliability scheme is proposed: first, a specific typical signal waveform is generated by a programmable digital signal generator and added to the cable input end, and then the signal is collected by the LMS acquisition system, and the spectrum and channel correlation analysis is performed. Then, the spectrum results are compared with the results of the signal generated by the signal generator directly added to the LMS acquisition system input end for frequency spectrum analysis, the common features and differences of the two spectrum graphs are found out, and then it is determined whether the cable connector of the channel is connected reliably, and the principle diagram of the measurement scheme is shown in Figure 2 .

[0060] The theoretical principles of realizing this scheme mainly have two: one is that theoretically the connector and the cable can be equivalent to a mathematical model composed of resistance and capacitance. Most of the actual connectors are round cable plugs, and the calculation formula of the difference film capacitance C between the two pins on the connector is:

[0061]

[0062] Wherein, ε is the dielectric constant of the medium material between the two pins; S is the distance between the two pins (mm); d is the pin diameter (mm); D is the diameter of the circular connector (mm).

[0063] The cable on the circuit can be equivalent to a low-pass filter, and its equivalent schematic diagram is shown in Figure 3 The upper limit medium frequency f c of the filter is:

[0064] f c = 1 / πRC (7)

[0065] Wherein R is the resistance of the circuit, unit Ω; C is the difference film capacitance between the two pins, unit F.

[0066] It can be seen that the inspection of the reliability of the connector and the cable has a great relationship with the line capacitance and resistance. The change of the entire line capacitance and resistance will affect the change of the line frequency component; two is from the experience of data analysis. A reliable and safe connection will reflect fixed frequency change characteristics on the frequency spectrum diagram. A significant feature of the frequency spectrum of an unreliable connection is that the frequency spectrum diagram has a sudden frequency change and more sudden frequency components.

[0067] The method for realizing this scheme is to design a waveform containing low frequency, medium frequency and high frequency characteristics by self-programming algorithm, and then send it to two signal generators by computer. Compare and analyze the previous line spectrum data, and perform channel correlation analysis to determine the reliability of the line. Through this scheme, not only can the more reliable measurement channels be selected quantitatively, but also the detection method is more scientific and reasonable than directly measuring the line insulation and resistance. At the same time, this method automatically realizes the circuit reliability check through a programmable signal generator on a computer, and the realization method is simple and efficient.

[0068] Both theory and practice show that the high frequency component of a signal plays an important role in predicting the occurrence of a fault, while the low frequency component indicates the fault mode when the fault occurs. Therefore, the extraction of the rapidly changing signal features is often based on the frequency domain. The rapidly changing feature data refers to the relevant data extracted from the rapidly changing time domain signal by means of FFT and other related signal processing means, which includes the total vibration value of the rapidly changing signal, the amplitude of the main frequency and its various multiple frequencies, and the residual amount, etc. The total vibration value refers to the maximum value of the rapidly changing time domain signal curve, the amplitude of the various multiple frequencies is obtained by converting the rapidly changing time domain signal into a frequency domain signal, i.e. a frequency spectrum, through FFT transformation or other signal processing algorithms, and then extracting the amplitude at the specific frequency point of interest in the frequency spectrum of the rapidly changing signal. The residual amount refers to the residual part after the total extreme value of the rapidly changing signal is subtracted from the amplitude at the various multiple frequencies, and is used to reflect the size of the rapidly changing energy at other frequencies except the characteristic frequencies.

[0069] For the rapidly changing measurement signal, it contains two aspects: one is the noise monitoring situation of the rapidly changing measurement system several days before each test. Through the monitoring of the noise of the rapidly changing measurement system over a period of time, it is found that the noise gradually decreases from morning to afternoon as a whole, and the 50Hz interference in the noise is relatively obvious. The monitoring of the same channel shows that the 50Hz, 150Hz, and 250Hz power frequency interference in the spectrum distribution changes not too obviously at different time periods, and the mode has a certain fixity, but the distribution of the remaining frequencies is greatly related to the insulation condition of the cable and the connector. Therefore, the total extreme value can be used to record the energy condition of each channel, the 50Hz, 150Hz, and 250Hz power frequency interference can be taken as the main frequency of each channel for statistics, and the remaining frequencies can be taken as the residual amount for statistics. The other aspect is that different frequency signals are applied to each rapidly changing measurement system, the time domain amplitude range, deviation, and drift of the measured data are determined, and the corresponding frequency spectrum analysis is performed on each channel to determine the statistical features such as the total extreme value, the main frequency, and the residual amount of each channel. Then, the transverse and longitudinal data comparison of the multiple data of these statistical quantities is performed to determine whether the connector of the channel is abnormal, and this method can also be used to screen the most stable channel and the performance stability of each channel.

[0070] The application will be further described below in combination with the drawings and specific embodiments.

[0071] A reliability checking method for a connector in a rapidly changing measurement system based on an LMS acquisition device, referring to Figure 1The rapidly changing measurement system based on the LMS acquisition device comprises an adapter 3, a front interval adapter cabinet 5, an LMS acquisition device 9 and an upper computer 11, the input end of the adapter 3 is connected with the vibration sensor 121 of the vibration block 122 on the rocket engine 12 through the first lead 2, the output end of the adapter 3 is connected with the input end of the front interval adapter cabinet 5 through the movable cable 4, the output end of the front interval adapter cabinet 5 is connected with the first input end of the LMS acquisition device 9 through the long-range main cable 6, and the LMS acquisition device 9 is connected with the upper computer 11 through the network cable 10; the signal acquisition channel comprises the first lead 2, the adapter 3, the movable cable 4, the adapter cabinet 5 and the long-range main cable 6; the two ends of the first lead 2, the movable cable 4 and the long-range main cable 6 are provided with connectors;

[0072] Referring to Figure 2 The steps of the embodiment are as follows:

[0073] Step 1, the first digital signal generator 1 and the second digital signal generator 7 are prepared and started, the first digital signal generator 1 and the second digital signal generator 7 generate the same detection waveform signals, that is, the first signal and the second signal, and wait until the first signal and the second signal are stable; wherein the detection waveform is a sine function, the frequency f is 10 kHz, the amplitude A is 5 V, and the initial phase

[0074] Step 2, the first lead 2 is removed from the rocket engine 12 and connected with the output end of the first digital signal generator 1, and the output end of the second digital signal generator 7 is connected with the second input end of the LMS acquisition device 9 through the second lead 8; usually, the first lead 2 is connected with the vibration sensor 121 of the vibration block 122 on the rocket engine 12, so it needs to be removed;

[0075] Step 3, the LMS acquisition device 9 starts to collect the first signal and the second signal by sending an instruction through the upper computer 11, and when the preset collection time t is greater than or equal to 300 s or the preset sampling point number N is greater than or equal to 6*10 5 , the LMS acquisition device 9 completes and stops collecting; the LMS acquisition device 9 completes and stops collecting;

[0076] Step 4, the first signal and the second signal collected by the LMS acquisition device 9 in step 3 are sorted to generate result data in *.txt format; the result data is converted from *.txt format to *.unv format and imported into a data processing software; the result data is stored;

[0077] Step 5, the data processing software processes and analyzes the data to obtain characteristic information of the first signal and the second signal;

[0078] Step 5.1, the first signal and the second signal are divided into equal time periods;

[0079] Step 5.2, analyzing the first signal and the second signal in each time period respectively in the navigator module of the LMS data processing software to obtain the average spectrogram, the color spectrum and the slice graph of the first signal and the second signal;

[0080] Step 5.3, obtaining the spectral shape, the peak position and the amplitude size data of the first signal and the second signal by using the obtained average spectrogram, the color spectrum and the slice graph;

[0081] Step 6, comparing the characteristic information of the first signal and the second signal, setting a preset reasonable range; if the deviation of the characteristic information of the first signal and the second signal is within the preset reasonable range, it is determined that the connection of all connectors in the rapid change measurement system based on the LMS acquisition device is reliable, and the reliability check is completed; if the deviation of the characteristic information of the first signal and the second signal is not within the preset reasonable range, the following is executed:

[0082] comparing the characteristic information of the first signal and the second signal, setting a preset reasonable range; if the deviation of the characteristic information of the first signal and the second signal is within the preset reasonable range, it is determined that the connection of all connectors in the rapid change measurement system based on the LMS acquisition device is reliable, and the reliability check is completed; if the deviation of the characteristic information of the first signal and the second signal is not within the preset reasonable range.

Claims

1. A method for checking the reliability of a signal acquisition channel in a LMS acquisition device-based rapid change measurement system, the LMS acquisition device-based rapid change measurement system comprising an adapter (3), a front interval adapter cabinet (5), a LMS acquisition device (9) and a host computer (11), the input end of the adapter (3) being connected to a rocket engine (12) through a first lead (2), the output end of the adapter (3) being connected to the input end of the front interval adapter cabinet (5) through a movable cable (4), the output end of the front interval adapter cabinet (5) being connected to the first input end of the LMS acquisition device (9) through a long-range main cable (6), the LMS acquisition device (9) being connected to the host computer (11) through a network cable (10); the signal acquisition channel comprises the first lead (2), the adapter (3), the movable cable (4), the adapter cabinet (5) and the long-range main cable (6); both ends of the first lead (2), the movable cable (4) and the long-range main cable (6) are provided with connectors; the method is characterized in that, The method comprises the following steps: Step 1, prepare the first digital signal generator (1) and the second digital signal generator (7) and start, make the first digital signal generator (1) and the second digital signal generator (7) generate the same detection waveform signal, respectively, the first signal and the second signal, wait until the first signal and the second signal are stable; Step 2, remove the first lead (2) from the device to be tested, and connect the output end of the first digital signal generator (1) and the second digital signal generator (7) to the second input end of the LMS acquisition device (9) through the second lead (8); Step 3, send instructions through the host computer (11) to make the LMS acquisition device (9) start collecting the first signal and the second signal, and complete and stop collecting when the first preset condition is met; Step 4, send the first signal and the second signal collected by the LMS acquisition device (9) in step 3 to the host computer (11), generate result data after processing, and arrange the result data; Step 5, the host computer (11) processes and analyzes the result data to obtain characteristic information of the first signal and the second signal; Step 6, compare the characteristic information of the first signal and the second signal, set a reasonable preset range; if the deviation of the characteristic information of the first signal and the second signal is within the reasonable preset range, it is determined that the connection of all connectors in the LMS acquisition device based rapid change measurement system is reliable, and the reliability check is completed; if the deviation of the characteristic information of the first signal and the second signal is not within the reasonable preset range, change the connection position of the first digital signal generator (1) in the signal collection channel and repeat steps 3-5 to determine the fault position.

2. The reliability check method of the signal collection channel in the LMS acquisition device based rapid change measurement system according to claim 1, wherein: In step 1, the detection waveform is a sine function, the frequency f=10 kHz, the amplitude A=5 V, and the initial phase φ=0.

3. The reliability check method of the signal collection channel in the LMS acquisition device based rapid change measurement system according to claim 2, wherein: The first preset condition described in step 3 is specifically: reaching a preset collection time length t or a preset sampling point number N, t≥300s, N≥6×10 5 .

4. The reliability check method of the signal collection channel in the LMS acquisition device based rapid change measurement system according to claim 3, wherein: In step 4, the result data is stored in *.txt format; "arranging the result data" specifically means converting the result data from *.txt format to *.unv format.

5. The reliability check method of the signal collection channel in the LMS acquisition device based rapid change measurement system according to claim 4, wherein: In step 5, the characteristic information includes frequency spectrum shape, peak position and amplitude size.

6. The reliability check method of the signal collection channel in the LMS acquisition device based rapid change measurement system according to claim 5, wherein: In step 6, the reasonable preset range is specifically: the similarity of the frequency spectrum shape of the two signals is ≥80%, the phase value deviation percentage of the peak value is ≤5%, and the amplitude size deviation percentage is ≤10%. 7.The reliability checking method of a signal acquisition path in a fast-changing measurement system based on an LMS acquisition device according to claim 6, characterized in that: in step 6, the connection position of the first digital signal generator (1) is changed and steps 3-5 are repeatedly executed, and the fault position is determined as follows: α) the first lead wire (2) is removed from the output end of the first digital signal generator (1), the active cable (4) is removed from the output end of the adapter (3) and connected to the output end of the first digital signal generator (1), steps 3-5 are sequentially executed, and the characteristic information of the first signal and the second signal is compared; if the deviation of the characteristic information of the first signal and the second signal is within a preset reasonable range, it is determined that the fault is located on the first lead wire (2) or the adapter (3), and step β1) is executed; if the deviation of the characteristic information of the first signal and the second signal is not within the preset reasonable range, step β2) is executed; β1) a new first lead wire (2) is replaced, then the output end of the first digital signal generator (1) is connected to the input end of the first lead wire (2), steps 3-5 are sequentially executed, and the characteristic information of the first signal and the second signal is compared; if the deviation of the characteristic information of the first signal and the second signal is within a preset reasonable range, it is determined that the fault is located on the first lead wire (2); if the deviation of the characteristic information of the first signal and the second signal is not within the preset reasonable range, it is determined that the fault is located on the adapter (3); and the reliability checking is completed; β2) a new active cable (4) is replaced, then the active cable (4) is connected to the output end of the first digital signal generator (1), steps 3-5 are sequentially executed, and the characteristic information of the first signal and the second signal is compared; if the deviation of the characteristic information of the first signal and the second signal is within a preset reasonable range, it is determined that the fault is located on the active cable (4), and the reliability checking is completed; if the deviation of the characteristic information of the first signal and the second signal is not within the preset reasonable range, step γ) is executed; γ) the long-range main cable (6) is removed from the output end of the front interval adapter cabinet (5) and connected to the output end of the first digital signal generator (1), steps 3-5 are sequentially executed, and the characteristic information of the first signal and the second signal is compared; if the deviation of the characteristic information of the first signal and the second signal is within a preset reasonable range, it is determined that the fault is located on the front interval adapter cabinet (5); if the deviation of the characteristic information of the first signal and the second signal is not within the preset reasonable range, it is determined that the fault is located on the long-range main cable (6); and the reliability checking is completed. 8.The reliability checking method of a signal acquisition path in a fast-changing measurement system based on an LMS acquisition device according to claim 7, characterized in that: step 5 is specifically as follows: step 5.1, dividing the first signal and the second signal into equal time periods; step 5.2, analyzing the first signal and the second signal in each time period in the navigator module of the LMS data processing software to obtain the average frequency spectrum, the color spectrum and the slice diagram of the first signal and the second signal. ​ ​ ​ ​ ​ ​ ​ ​ Step 5.

3. Using the obtained average spectrogram, chromatogram and slice, the spectral shape, peak position and amplitude size data of the first signal and the second signal are obtained.

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