Aerospace dynamic vibration signal acquisition system and use method

Abstract

The invention discloses a spaceflight dynamic vibration signal acquisition system and method. The spaceflight dynamic vibration signal acquisition system comprises an upper computer, a portable vibration signal acquisition unit, a signal conditioning unit, an accelerometer, a communication module, a trigger and synchronization module and a power supply module. Through cooperative work of the NI-PXIe-6358 card and the self-developed dynamic data acquisition card, 16-channel synchronous acquisition is realized, and the highest sampling rate reaches 200kSa / s; the FPGA is adopted to accumulate the pulse number of the phases ABZ of the encoder in real time, and an external trigger interval dynamic shielding mechanism is combined, so that the synchronism of multiple measuring points and the data validity are ensured; the system supports DC 18V-36V wide voltage input and sleep mode control, and adapts to a complex power supply environment. The method comprises the processes of initial configuration, intelligent trigger acquisition, synchronous signal control and exception handling, and dynamic parameter management is realized through LabVIEW. The system solves the problems of insufficient synchronism, weak anti-interference capability and low localization level of traditional equipment, can be extensively applied to acquisition of multiple types of signals such as temperature and impact, and remarkably improves the test run test efficiency and data reliability of an aerospace power system.

Description

Technical Field

[0001] The present invention relates to the technical field of aerospace power system testing, and specifically provides an aerospace power vibration signal acquisition system and a usage method, which are particularly suitable for the acquisition and analysis of high-synchronization vibration data at multiple measurement points during system-level hot tests. Background Technique

[0002] Currently, PXIe buses are mainly used in equipment in the field of dynamic testing. Equipment chassis based on PXIe buses have the advantages of flexibility, software customization, integrated technology of modular instruments, high data throughput, and high synchronization. Therefore, they have been well-received in the dynamic testing market since their introduction.

[0003] Since system-level hot tests have a large demand for the number of vibration points and a high synchronization requirement between measurement points, while meeting the environmental test requirements of commercial aerospace products, the service fees generated can be used for the research and development of autonomous equipment based on PXIe buses, accumulating technology and generating profits to form a virtuous cycle. Therefore, it is imperative to develop a vibration data acquisition system based on PXIe buses. Moreover, with the development of industrial production and the continuous improvement of the modernization level of equipment, the performance requirements for equipment are also getting higher and higher. Therefore, the condition monitoring and fault diagnosis of equipment have also become the focus of attention, especially in the aerospace field, where the equipment status needs to be monitored and analyzed in a timely manner.

[0004] Although existing data acquisition equipment based on PXIe buses has the advantages of high throughput and modularity, limited by foreign technology blockade, there are obvious shortcomings in the fields of high-speed and high-precision analog-to-digital converters (ADCs) and integrated analog channels in China. In addition, aerospace power system tests require high-synchronization acquisition at multiple measurement points, and traditional equipment is difficult to meet the real-time requirements in complex environments. Summary of the Invention

[0005] The present invention provides an aerospace power vibration signal acquisition system and method, aiming to solve the problems of low synchronization and weak anti-interference ability at multiple measurement points.

[0006] The technical solution adopted by the present invention is a vibration signal acquisition system for aerospace power, including: a host computer for data storage, time-domain acquisition, and frequency-domain processing; a vibration signal acquisition unit including a NI chassis, a dynamic data acquisition card, a data communication interface, and a signal connector; the dynamic data acquisition card includes a NI-PXIe-6358 card and a self-developed dynamic data acquisition card, supporting 16-channel synchronous acquisition with a maximum sampling rate of 200 kSa / s; a signal conditioning unit including a signal conditioning module and a panel electrical connector for conditioning vibration signals; an accelerometer, which is an IEPE type acceleration sensor with a range of 500 g to 5000 g and an output signal of ±10 V; a communication module supporting Ethernet and RS232 interfaces for data transmission; a trigger and synchronization module including an external trigger input, a synchronization signal output, and an encoder pulse counting function controlled by FPGA for realizing multi-point synchronous acquisition; a power supply module supporting DC 18V~36V input and having a sleep mode control function.

[0007] Preferably, the dynamic data acquisition card is based on an AD7606-8 analog-to-digital converter, supporting an external trigger signal interval judgment function. When the trigger interval is less than the preset sampling length, invalid triggers are automatically ignored.

[0008] Preferably, the FPGA accumulates the number of turns N and the number of pulses M of the encoder in real time. N and M are respectively stored in 16-bit registers and uploaded to the host computer synchronously with the trigger signal.

[0009] Preferably, the interface of the signal conditioning unit uses a DIN41612 double-row bent pin connector, supporting direct connection of analog signals and power input.

[0010] Preferably, the host computer realizes dynamic configuration of acquisition parameters through LabVIEW software, including sampling rate, number of channels, and trigger conditions.

[0011] A method for acquiring vibration signals for aerospace power includes the following steps: Initialization stage: The host computer issues parameter instructions to configure the sampling rate, the number of trigger points, and RS232 forwarded data. Standby mode: Default sleep state, and the working mode is switched through host computer instructions. Data acquisition: The acquisition is started by the rising edge of an external trigger. The FPGA synchronously records the encoder pulse numbers N and M and uploads the data to the host computer in real time through Ethernet. Synchronization control: The synchronization signal outputs a high level during acquisition and returns to a low level after stopping to ensure multi-point synchronization. Exception handling: When the external trigger interval is less than the preset sampling length, invalid triggers are automatically blocked.

[0012] Preferably, the encoder pulse counting includes ABZ phase detection, where the pulse count increases during forward rotation and decreases during reverse rotation, and the complete number of turns is recorded through the Z phase.

[0013] The beneficial effects of the present invention are as follows: The present invention supports high-synchronization acquisition of multiple measurement points with an error less than 1 μs; it is compatible with domestic hardware, reducing R & D costs; the intelligent trigger mechanism reduces the amount of redundant data and improves efficiency; it has strong scalability and can adapt to various types of sensors such as temperature and shock. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Portable vibration signal acquisition system diagram.

[0015] Figure 2 Block diagram of the dynamic data acquisition card design process.

[0016] Figure 3 Acquisition work flow chart.

[0017] Figure 4 Schematic diagram of data acquisition.

[0018] Figure 5 Schematic diagram of interface definition. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0020] The basic principle of the vibration signal acquisition system is as follows Figure 1 , and it mainly consists of a host computer CPU, a portable vibration signal acquisition unit, a signal conditioning unit, an accelerometer, etc.

[0021] Among them: Host computer: computer monitor, LabVIEW time-domain acquisition and storage, LabVIEW frequency-domain processing; Vibration acquisition unit: 9-slot NI chassis, NI dynamic data acquisition card, self-developed dynamic data acquisition card, data communication interface and signal connector, equipment enclosure; On the premise that the basic principle of "making use of existing equipment" remains unchanged, in order to meet the requirements of vibration test indicators, the original NI-PXIe-6358 card is used in the newly built system. Signal conditioning unit: signal conditioning module, panel electrical connector, equipment enclosure; Accelerometer: Measuring range IEPE acceleration sensing with 500 g / 1000 g / 5000 g (range required by existing models), powered by 2 - 10 mA, and the output signal is ±10 V.

[0022] 1) Main parameters and functions Low power consumption, power input: DC18V~36V Sampling rate: AD7606-8, up to 200kSa / s; Number of channels: 16-channel synchronous acquisition for a single card; Ethernet communication rate: 100Mbit / s or 1000 Mbit / s RS232 interface: 9600 baud rate, forwarding data passed in by the host computer through the Ethernet interface, up to 128 bytes; External trigger input: 3.3V-TTL level, rising edge trigger; Synchronization signal output: 3.3V-TTL level, high level during signal acquisition, low level after acquisition stops; Sleep mode: The ADC is default in the sleep mode after power-on, and the sleep / working state of the ADC can be controlled by the host computer; Encoder pulse input: Collecting ABZ phase signals, the positive and negative rotations of the encoder can be judged. For each positive rotation pulse, the count is +1, and for each negative rotation pulse, the count is -1. Record the cumulative pulse count and the number of rotation circles, denoted as N circles and M pulses; among them, the N register is 16 bits and the M register is 16 bits; (Generally, AB is used to judge the direction and record the number of M, and Z is used to record the number of N), as follows Figure 2 Shown: 2) Working process of the system data acquisition program AD standby mode: 1. It is default in the standby mode after power-on, and the FPGA controls the STBY pin of the AD7606 to switch between standby / working modes; 2. When in the standby mode, IO1~IO3 are at high level, and when in the working mode, IO1~IO3 (see the interface definition diagram) are at low level; 3. When the device is idle, the standby / working state can be controlled by sending instructions from the host computer; Initialization process: 1. Receive the instructions sent by the host computer and set various parameters, including: Sampling rate; Number of sampling points for each channel per trigger; Data that needs to be forwarded through the RS232 port; 2. Forward data through the RS232 port Device idle state: 1. When receiving the start instruction sent by the host computer, start acquisition; 2. If receiving new parameters sent by the host computer, re-initialize the parameters; Start collecting and uploading data: 1. When the data acquisition starts, the synchronization signal IO outputs a high level and returns to a low level at the end of the acquisition; 2. Trigger and acquire data according to the Figure 4 working mode; 3. After the acquisition starts, the FPGA continuously accumulates the number of turns and pulses rotated by the encoder until the acquisition stops, recorded as N turns and M pulses, where the N register is 16 bits and the M register is 16 bits; 4. Each time the external trigger input port detects a rising edge, the data is acquired and uploaded, and the values of N and M at the trigger moment are uploaded simultaneously; 5. When the interval of the external trigger signal is less than the sampling length, the trigger signal is not responded to; 3) Interface definition 1. The connector uses a DIN41612 connector, all of which are double-row, bent pin, male head, with a hole pitch of 2.54 mm; 2. A1 and A2 are analog signals, and A1-IN is directly connected to A1-OUT, and A2-IN is directly connected to A2-OUT on the board; 3. Vcc+ is the DC18~36V positive power input, and Vss- is the DC-18~-36V negative power input; 4. Reserved φ3 mounting holes are provided at the four corners.

[0023] Initialization process: 1. Receive the instructions sent by the host computer and set various parameters, including: Sampling rate; The number of sampling points for each channel for each trigger; Data that needs to be forwarded through the RS232 port; 2. Forward data through the RS232 port Device idle state: 1. Start acquiring data when receiving the start instruction sent by the host computer; 2. If a new parameter is received from the host computer, re-initialize the parameters; Start acquiring and uploading data: 1. When the data acquisition starts, the synchronization signal IO outputs a high level and returns to a low level at the end of the acquisition; 2. Trigger and acquire data according to the Figure 4 working mode; 3. After the acquisition starts, the FPGA continuously accumulates the number of turns and pulses rotated by the encoder until the acquisition stops, recorded as N turns and M pulses, where the N register is 16 bits and the M register is 16 bits; 4. Each time the external trigger input port detects a rising edge, the data is acquired and uploaded, and the values of N and M at the trigger moment are uploaded simultaneously; 5. When the interval of the external trigger signal is less than the sampling length, the trigger signal is not responded to; The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A space power vibration signal acquisition system, characterized in that, Comprising: A host computer (1) for data storage, time-domain acquisition and frequency-domain processing; a vibration signal acquisition unit (2) including an NI chassis, a dynamic data acquisition card, a data communication interface and a signal connector; the dynamic data acquisition card includes an NI-PXIe-6358 card and a self-developed dynamic data acquisition card, supporting 16-channel synchronous acquisition with a maximum sampling rate of 200 kSa / s; a signal conditioning unit (3) including a signal conditioning module and a panel electrical connector for conditioning the vibration signal; an accelerometer (4) which is an IEPE type acceleration sensor with a range of 500 g to 5000 g and an output signal of ±10 V; A communication module (5) supporting Ethernet and RS232 interfaces for data transmission; a trigger and synchronization module (6) including an external trigger input, a synchronization signal output, and an encoder pulse counting function controlled by an FPGA for achieving multi-point synchronous acquisition; a power supply module (7) supporting DC 18V~36V input and having a sleep mode control function.

2. The system according to claim 1, characterized in that, The dynamic data acquisition card is based on an AD7606-8 analog-to-digital converter and supports an external trigger signal interval judgment function. When the trigger interval is less than the preset sampling length, invalid triggers are automatically ignored.

3. The system according to claim 1, wherein The FPGA real-time accumulates the number of turns N and the number of pulses M of the encoder. N and M are respectively stored in 16-bit registers and are synchronously uploaded to the host computer (1) along with the trigger signal.

4. The system according to claim 1, wherein The interface of the signal conditioning unit (3) uses a DIN41612 double-row bent pin connector, supporting direct connection of analog signals and power input.

5. The system according to claim 1, wherein The host computer (1) realizes dynamic configuration of acquisition parameters through LabVIEW software, including sampling rate, number of channels and trigger conditions.

6. A method for collecting aerospace dynamic vibration signals, based on the system according to any one of claims 1-5, characterized in that, Including the following steps: Initialization stage: The host computer (1) issues parameter instructions to configure the sampling rate, the number of trigger points and RS232 forwarded data; Standby mode: The default sleep state, and the working mode is switched through the instruction of the host computer (1); Data acquisition: The acquisition is started by the rising edge of the external trigger. The FPGA synchronously records the number of encoder pulses N and M, and uploads the data in real time through Ethernet; Synchronization control: The synchronization signal outputs a high level during acquisition and returns to a low level after stopping to ensure multi-point synchronization; Exception handling: When the external trigger interval is less than the preset sampling length, invalid triggers are automatically masked.

7. The method according to claim 6, wherein The encoder pulse counting includes ABZ phase detection. The number of pulses increases during forward rotation and decreases during reverse rotation, and the complete number of turns is recorded through the Z phase.

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