A multi-channel signal acquisition device and method for impact damage test environment

Abstract

The present invention relates to the field of multi-channel signal acquisition technology, and in particular to a multi-channel signal acquisition device and method for impact damage test environments, including: step 1, an anti-interference trigger acquisition method based on a joint intelligent trigger module and an external vibration reduction structure with soft and hard coordination: reducing the coupling of interference signals through a multi-directional vibration reduction base structure design targeted at the impact test environment and a circuit board vibration reduction layout through simulation analysis; step 2, providing a data length adaptive storage method: real-time judgment and identification of signals is performed through a joint intelligent trigger module, and a pre-trigger cache module stores signals cyclically, and when a trigger signal is reached, the joint intelligent trigger module simultaneously counts the effective signal duration. The present invention can perform storage-type acquisition of transient change signals in an impact damage environment, has good anti-interference performance compared to a general storage device, and effectively improves the reliable triggering and acquisition problems of the acquisition device in a complex environment.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-channel signal acquisition, and in particular to a multi-channel signal acquisition device and method for an impact damage test environment. Background Art

[0002] In order to accurately describe the damage state of key components inside armored vehicles before and after impact damage tests, multiple parameters need to be measured.

[0003] At present, the overall duration of this type of test is relatively long, up to 3 to 4 hours, but the cumulative duration of effective signals that need to be collected in the test is much smaller. The general storage and acquisition device is always in the collection and storage working mode, which will generate a large amount of redundant data, and the effective data accounts for less than 1%; in the conventional automatic trigger acquisition method, most of them are single criterion, and the false trigger rate is relatively large in the impact damage environment. In addition, during the test, there are single warhead strikes and multiple warhead strikes, and the length of the signal to be collected is also inconsistent. Setting a fixed acquisition time will cause signal redundancy or incomplete effective signals.

[0004] Therefore, in order to solve the above problems, the present application proposes a multi-channel signal acquisition device and method for an impact damage test environment from two aspects of reliable trigger acquisition and data length adaptive storage in an impact damage test environment. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings existing in the prior art, and to propose a multi-channel signal acquisition device and method for an impact damage test environment, which can perform storage-type acquisition of transient change signals in an impact damage environment, has good anti-interference performance, adaptively stores valid data, reduces data redundancy, and improves the efficiency of later data processing.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A multi-channel signal acquisition device for impact damage test environment, comprising a sensor unit, an acquisition unit and a host computer connected in sequence;

[0008] The sensor unit includes an acceleration sensor, a strain sensor and a shock wave sensor;

[0009] The acquisition unit includes an analog conditioning circuit, an AD acquisition conversion circuit, a DDR dynamic cache module, an algorithm processing module, an SD card static memory and an Ethernet communication interface;

[0010] The acceleration sensor, strain sensor and shock wave sensor are all connected to the analog conditioning circuit, the analog conditioning circuit is connected to the AD acquisition conversion circuit, the AD acquisition conversion circuit is connected to the DDR dynamic cache module, the DDR dynamic cache module is respectively connected to the algorithm processing module and the SD card static memory, and the SD card static memory is connected to the host computer through an Ethernet communication interface.

[0011] The present invention also provides a collection method of a multi-channel signal collection device for an impact damage test environment, comprising the following steps:

[0012] Step 1, an anti-interference trigger acquisition method based on the soft and hard coordination of a joint intelligent trigger module and an external vibration reduction structure: reduce the coupling of interference signals by designing a multi-directional vibration reduction base structure targeted at the impact test environment and a circuit board vibration reduction layout through simulation analysis; and reliably trigger the acquisition signal through a joint intelligent trigger method based on a combination criterion of multiple features of the measured signal, thereby achieving the purpose of anti-interference acquisition in an impact damage test environment;

[0013] Step 2. Provide a data length adaptive storage method: use a joint intelligent trigger module to perform real-time judgment and identification on the signal, and the pre-trigger cache module to store the signal cyclically. When the trigger signal arrives, the joint intelligent trigger module simultaneously counts the duration of the effective signal, and determines the final cached data size based on the final marking duration, thereby reducing the efficiency of subsequent effective data extraction.

[0014] Preferably, in step 1, the strain and acceleration distribution of circuit boards with different constraints in an impact damage environment are obtained through simulation, and each area of ​​the base plate and the acquisition board is divided into multiple stability levels. Then, based on the regional divisions, the electronic components are laid out according to their importance and fragility.

[0015] Preferably, in step 1, a joint intelligent trigger module based on a combination criterion of multiple characteristics of the measured signal is proposed for the shock wave and acceleration signal characteristics measured in an impact damage environment, wherein the signal characteristics include: rise time, duration, joint trigger judgment based on multi-window accumulation, mean energy change and multi-channel independent judgment, and correlation.

[0016] Preferably, the joint intelligent trigger module records and identifies the rise time and duration of the noise signal, shock wave signal and acceleration signal; records the energy change of the real-time signal by accumulating three windows and taking the average; when a channel is triggered, the joint intelligent trigger module can determine whether it is a valid trigger based on the triggering conditions of multiple channels.

[0017] Preferably, in step 2, the amount of data stored each time is adaptively recorded based on the duration of the effective signal recorded by the joint intelligent trigger module each time the signal is triggered, which can significantly improve the efficiency of subsequent data processing when the overall test time is long and the effective signal duration varies.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The acquisition device of the present invention has a compact structure and high functional integration. In an impact damage environment, it can reliably trigger the impact acceleration, strain, and shock wave signals received by key components inside the armored vehicle, adaptively store effective data, reduce data redundancy, and improve the efficiency of later data processing.

[0020] 2. The present invention can perform storage-type acquisition of transient change signals in an impact damage environment. Compared with general storage devices, it has good anti-interference performance and effectively improves the reliable triggering and acquisition problems of the acquisition device in a complex environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the collection device of the present invention;

[0022] Figure 2 It is a schematic diagram of the system composition of the acquisition device of the present invention;

[0023] Figure 3 It is a schematic diagram of the arrangement of the bottom plate components of the acquisition device of the present invention;

[0024] Figure 4 This is a schematic diagram of the arrangement of components of a collection board of the collection device of the present invention;

[0025] Figure 5 This is a schematic diagram of the bottom plate PCB of the acquisition device of the present invention;

[0026] Figure 6 This is a schematic diagram of a collection board PCB of the collection device of the present invention;

[0027] Figure 7 This is a schematic diagram of the principle of the window energy trigger module of the present invention;

[0028] Figure 8 It is a schematic diagram of the joint intelligent triggering process of the present invention. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0030] A multi-channel signal acquisition device for impact damage test environment, its appearance and structure are as follows Figure 1 As shown, it includes: a collection body 1 of the collection device, which contains a circuit board structure that realizes the collection function; a multi-directional vibration reduction base 2 is designed at the bottom to attenuate the energy transmitted to the collection device body from the bottom during the test.

[0031] Among them, the system composition of the multi-channel signal acquisition device is as follows: Figure 2 As shown, it includes a sensor unit, a collection unit and a host computer connected in sequence; the sensor unit includes an acceleration sensor, a strain sensor and a shock wave sensor;

[0032] The acquisition unit includes an analog conditioning circuit, an AD acquisition conversion circuit, a DDR dynamic cache module, an algorithm processing module, an SD card static memory and an Ethernet communication interface;

[0033] The acceleration sensor, strain sensor and shock wave sensor are all connected to the analog conditioning circuit, the analog conditioning circuit is connected to the AD acquisition conversion circuit, the AD acquisition conversion circuit is connected to the DDR dynamic cache module, the DDR dynamic cache module is respectively connected to the algorithm processing module and the SD card static memory, and the SD card static memory is connected to the host computer through an Ethernet communication interface.

[0034] In this embodiment, the acquisition device has a compact structure and high functional integration. In an impact damage environment, it can reliably trigger the impact acceleration, strain, and shock wave signals received by key components inside the armored vehicle, adaptively store valid data, reduce data redundancy, and improve the efficiency of later data processing. In actual application, the sensor unit is connected to a pre-matched channel through a short cable. The input analog signal first passes through the analog conditioning circuit and then enters the A / D analog-to-digital conversion module to convert the analog signal into a digital signal with a precision bit width of 16 bits; the digital signal of each channel is first processed into the internal DDR dynamic cache module, and then transferred from DDR to the SD card static storage. The upper computer accesses the SD card through the Ethernet communication interface of the lower computer to retrieve the data stored in the lower computer.

[0035] A collection method of a multi-channel signal collection device for an impact damage test environment comprises the following steps:

[0036] Step 1, an anti-interference trigger acquisition method based on the soft and hard coordination of a joint intelligent trigger module and an external vibration reduction structure: reduce the coupling of interference signals by designing a multi-directional vibration reduction base structure targeted at the impact test environment and a circuit board vibration reduction layout through simulation analysis; and reliably trigger the acquisition signal through a joint intelligent trigger method based on a combination criterion of multiple features of the measured signal, thereby achieving the purpose of anti-interference acquisition in an impact damage test environment;

[0037] Step 2. Provide a data length adaptive storage method: use a joint intelligent trigger module to perform real-time judgment and identification on the signal, and the pre-trigger cache module to store the signal cyclically. When the trigger signal arrives, the joint intelligent trigger module simultaneously counts the duration of the effective signal, and determines the final cached data size based on the final marking duration, thereby reducing the efficiency of subsequent effective data extraction.

[0038] Specifically, in step 1, the strain and acceleration distribution of circuit boards with different constraints in an impact damage environment are obtained through simulation, and each area of ​​the base plate and acquisition board is divided into multiple stability levels. Then, based on the regional divisions, the electronic components are laid out according to their importance and fragility.

[0039] Specifically, in step 1, a joint intelligent trigger module based on a combination of multiple characteristics of the measured signal is proposed for the shock wave and acceleration signal characteristics measured in an impact damage environment, wherein the signal characteristics include: rise time, duration, multi-window accumulation, mean energy change and multi-channel independent judgment, and correlation-based joint trigger judgment.

[0040] Specifically, the joint intelligent trigger module records and identifies the rise time and duration of noise signals, shock wave signals, and acceleration signals; records the energy changes of real-time signals by accumulating three windows and taking the average; when a channel is triggered, the joint intelligent trigger module can determine whether it is a valid trigger based on the triggering conditions of multiple channels.

[0041] Specifically, in step 2, the joint intelligent trigger module records the duration of the effective signal each time the signal is triggered, and the amount of data stored each time is adaptively recorded, which can significantly improve the efficiency of subsequent data processing when the overall test time is long and the effective signal duration varies.

[0042] Example

[0043] PCB circuit board layout design:

[0044] In terms of circuit board constraint design, the circuit board and the equipment housing of the present invention are mostly fixed by bolts or inserted or pressed, that is, fixed support constraints. Different constraint methods will result in different vibration responses of the circuit board. According to the maximum response of the displacement, velocity, acceleration and stress of the circuit board under various constraint conditions, the present invention will design the acquisition board for fixed support constraints, adopt a bolt-fixed constraint method for the bottom plate, and place rubber pads at the bolt installation location to reduce the overall level of acceleration.

[0045] In the layout of the circuit board, through simulation analysis of the circuit board, the peak parameters of the acceleration frequency response curve of the electronic components near the edge of the circuit board are better than those of the components located in the center. Therefore, in terms of component layout, the present invention should try to layout the key components near the edge of the circuit board. The present invention divides the area of ​​the bottom plate as follows Figure 3 As shown in the figure, the area division of the acquisition board is as follows Figure 4 As shown in the figure, area 1 is the dangerous area where the circuit board has a large strain displacement when it is impacted; area 3 is a relatively stable area in the circuit board; and area 2 is the part with a moderate impact when it is impacted. Figure 5 As shown, the acquisition board PCB is as follows Figure 6 shown.

[0046] Intelligent trigger module design:

[0047] In the present invention, the power module is based on a lithium battery and supplies power to each sub-functional module through a BUCK or a boost circuit; the acceleration and shock wave signal conditioning module in the analog circuit module converts the signal collected by the sensor into a voltage analog signal in the range of ±5V; after analog-to-digital conversion, 6 groups of digital signals with an accuracy of 16 bits and a sampling rate of 1M / s are output; the trigger module receives 6 digital signals from the A / D analog-to-digital conversion module, and identifies and judges the signals after real-time processing.

[0048] There are two main situations that cause false triggering in practical applications of trigger acquisition. One is when the signal drifts; the other is when the signal contains step glitch signals.

[0049] Among the signals collected by the follow-up acquisition unit, the acceleration and shock wave signals have good stability due to the signal output principle of the piezoelectric sensor, and are suitable as the input objects of the intelligent trigger module. In the process of signal acquisition, the complex and changeable test environment often causes the step burr signal to be coupled into the signal, resulting in false triggering. The duration of the burr signal is usually only a few microseconds, while the duration of the shock wave signal and the acceleration signal can reach more than ten milliseconds or even longer.

[0050] In view of the above problems, the present invention designs an intelligent triggering method, which combines the signal rising trend judgment, the window energy change judgment and the multi-channel signal joint judgment. Figure 7 shown.

[0051] Before entering the pre-trigger state, the trigger module samples the input signal with a depth of m, and takes the average value X after accumulating the sampled signal as the reference value. The window is divided into 3 and then stored in a loop. The absolute value of the data in each window is accumulated and the average value X1, X2, and X3 are taken. The ratio of the average value of each window to the reference value X is calculated as N1, N2, and N3. When the ratio is greater than or equal to the empirical value N, it is determined that the window is currently in a high energy state, which can be represented by binary 1. Other cases are considered to be low energy states, represented by binary 0.

[0052] The present invention sets 150 registers (reg_0 to reg_149) of the intelligent trigger module of the acquisition device, all of which have a starting value of 0, and can cyclically store signals of 150 sampling cycles. The window 1 register group is numbered reg_0 to reg_49, the window 2 register group is numbered reg_50 to reg_99, and the window 3 register group is numbered reg_100 to reg_149. Therefore, the starting value of binary X is 3'b000; then, the reset signal is pulled high, the trigger module starts working and initializes the program. The trigger module first determines whether the signal is a glitch signal. When there is a signal with a long duration, it is judged by the window recognition module. At the beginning of the acquisition, the register group stores the target signal data in a loop, that is, the target signal is shifted and stored. At the same time, window 1, window 2, and window 3 accumulate the registers contained in their respective windows. Because it is a shift storage, only the first digit value needs to be added or subtracted from the original value each time; the trigger module determines that the energy state of the three windows changes from 000 to 111. At this time, the trigger module analyzes the judgment of multiple channels. When 3 or more channels meet the trigger acquisition requirements, the trigger module outputs a high level and lasts for a certain period of time. After that, before the end signal of the follow-up acquisition unit is issued, the trigger module will keep the cyclic trigger state unchanged.

[0053] According to the difference in duration of shock wave, acceleration signal and step glitch signal and previous test experience, the depth of the three windows is set to 50, and the experience value N is set to 1.15. That is, when the duration of the target signal change reaches more than 50us and the average value is greater than 1.15 times the reference value, the follow-up acquisition unit will trigger the signal acquisition.

[0054] The overall triggering process of the present invention is as follows: Figure 8As shown, in order to solve the problem of continuous glitch signal interfering with the trigger module, the present invention takes advantage of FPGA parallel processing. While the trigger module performs window operation, it counts the time for the mutation signal to return from the peak value to the reference value. When the actual count value is lower than the preset value, the signal is determined to be a glitch signal. The preset value can be set to 10 according to test experience.

[0055] In addition, the trigger module will make joint judgments on multiple signals to avoid the probability of false triggering caused by noise in a single channel. The ratio can be preset to 0.5, that is, the trigger module will simultaneously make trigger judgments on the acceleration and shock wave signals (a total of 6 channels in the present invention) of the follow-up acquisition unit. When the number of trigger signals reaches 3 or more, the follow-up acquisition unit starts a trigger acquisition process.

[0056] Adaptive storage of effective signal length:

[0057] After the present invention starts working, it first initializes the system; then starts to start A / D for signal input and controls DDR to record data cyclically to enter the pre-trigger state. The trigger module identifies and judges the target signal, and provides a trigger signal to the system when the trigger condition is met. After that, DDR records the post-trigger signal with a new storage address and retains the pre-trigger data. After one recording is completed, DDR stores a complete pre- and post-trigger data; then the acquisition unit transfers the dynamically cached data to the static storage medium SD card. Among them, the joint intelligent trigger unit will start to record the effective signal length of this trigger after identifying the effective signal, and send the recording duration data after the recording is completed. The PS end confirms the signal length to be recorded after the trigger according to the recording information and updates the address.

[0058] In summary, the present invention can perform storage-type acquisition of transient change signals in an impact damage environment, has good anti-interference performance compared to general storage devices, and effectively improves the reliable triggering and acquisition problems of the acquisition device in complex environments.

[0059] The description and practice disclosed in the present invention are easy to think and understand for ordinary technicians in the technical field, and several improvements and modifications can be made without departing from the principles of the present invention. Therefore, modifications or improvements made without departing from the spirit of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A collection method of a multi-channel signal collection device for an impact damage test environment, characterized in that: The multi-channel signal acquisition device comprises a sensor unit, an acquisition unit and a host computer connected in sequence; The sensor unit includes an acceleration sensor, a strain sensor and a shock wave sensor; The acquisition unit includes an analog conditioning circuit, an AD acquisition conversion circuit, a DDR dynamic cache module, an algorithm processing module, an SD card static memory and an Ethernet communication interface; The acceleration sensor, strain sensor and shock wave sensor are all connected to the analog conditioning circuit, the analog conditioning circuit is connected to the AD acquisition conversion circuit, the AD acquisition conversion circuit is connected to the DDR dynamic cache module, the DDR dynamic cache module is respectively connected to the algorithm processing module and the SD card static memory, and the SD card static memory is connected to the host computer through an Ethernet communication interface; The acquisition method of the multi-channel signal acquisition device comprises the following steps: Step 1, an anti-interference trigger acquisition method based on the soft and hard coordination of a joint intelligent trigger module and an external vibration reduction structure: reduce the coupling of interference signals by designing a multi-directional vibration reduction base structure targeted at the impact test environment and a circuit board vibration reduction layout through simulation analysis; and reliably trigger the acquisition signal through a joint intelligent trigger method based on a combination criterion of multiple features of the measured signal, thereby achieving the purpose of anti-interference acquisition in an impact damage test environment; Step 2, providing a data length adaptive storage method: the signal is judged and identified in real time by the joint intelligent trigger module, and the pre-trigger cache module stores the signal cyclically. When the trigger signal arrives, the joint intelligent trigger module counts the effective signal duration at the same time, and determines the final cached data size according to the last marking duration, thereby reducing the efficiency of subsequent effective data extraction; In step 1, a joint intelligent trigger module based on the combined criteria of multiple characteristics of the measured signal is proposed for the shock wave and acceleration signal characteristics measured in the impact damage environment, wherein the signal characteristics include: rise time, duration, multi-window accumulation, mean energy change and multi-channel independent judgment, and joint trigger judgment based on correlation.

2. The acquisition method of a multi-channel signal acquisition device for an impact damage test environment according to claim 1, characterized in that: In step 1, the strain and acceleration distribution of circuit boards with different constraints in an impact damage environment are obtained through simulation, and each area of ​​the base plate and acquisition board is divided into multiple stability levels. Then, based on the regional divisions, the electronic components are laid out according to their importance and fragility.

3. The acquisition method of a multi-channel signal acquisition device for an impact damage test environment according to claim 1, characterized in that: The joint intelligent trigger module records and identifies the rise time and duration of noise signals, shock wave signals and acceleration signals; it records the energy changes of real-time signals by accumulating three windows and taking the average; when a channel is triggered, the joint intelligent trigger module can determine whether it is a valid trigger based on the triggering conditions of multiple channels.

4. The acquisition method of a multi-channel signal acquisition device for an impact damage test environment according to claim 1, characterized in that: In step 2, the effective signal duration recorded by the joint intelligent trigger module each time the signal is triggered is used to adaptively record the amount of data stored each time, which can significantly improve the efficiency of subsequent data processing when the overall test time is long and the effective signal duration varies.

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