Multifunctional frequency characteristic test system and method

Abstract

The invention provides a multifunctional frequency characteristic test system and method. A computer control and simulation technology is adopted, a real-time simulation system is built, and an I / O interface collects a sweep frequency excitation signal of a standard instrument in real time and converts the sweep frequency excitation signal into an input signal type of a tested system; output signals of a tested system are collected, analyzed and calculated in real time, are subjected to digital-to-analog conversion through an I / O board card, and are accessed to an analysis channel of a standard instrument. The real-time simulation system sets an appropriate simulation period according to the control step length of the tested object, the real-time performance of the whole system is guaranteed, and the test result is not distorted.

Description

Technical Field

[0001] This invention belongs to the field of aviation ground test technology, and relates to a large-scale integrated test facility, the iron bird test rig, specifically a multi-functional frequency characteristic testing system and method. Background Technology

[0002] Frequency response testing is an important method for evaluating the dynamic characteristics and stability of control systems. In the aviation field, two methods are commonly used: The first method is fixed-frequency testing, where a sinusoidal signal is generated by a signal generator, injected into the system under test (SUT), and the system's response output is collected. The frequency response parameters of the system are then obtained through post-processing. The second method uses standard instruments. By setting relevant parameters of a dynamic signal analyzer, a frequency-sweeping signal with varying frequencies is generated and injected into the input of the SUT. The response signal of the SUT is then connected to the analysis channel of the dynamic signal analyzer, which directly outputs the frequency response test results for the corresponding channel.

[0003] The first method requires setting each frequency point individually for testing, which is time-consuming. Results are obtained through post-processing of the test data, leading to diverse results from different processing methods. The second method uses standard instruments; after frequency sweep testing, results are directly generated, and these instrument-based results have high industry acceptance. In the field of aerospace testing, the second method is typically used to test the frequency domain characteristics of the system. Depending on the number of instrument test channels, it can complete the testing of 1 to 4 response outputs of the system under test at once.

[0004] For frequency domain characteristic testing and stability reserve testing of modern advanced fly-by-wire flight control systems, there are numerous system input and output parameters to be tested, hundreds of test combinations, complex wiring work, and a large workload of switching and verifying various lines, making wiring prone to errors. Furthermore, the inputs and responses of modern fly-by-wire flight control systems are digital signals, which traditional standard instruments cannot directly excite and test, greatly limiting the scope of testing.

[0005] Modern aircraft control systems, especially flight control systems, have a large number and variety of input and output signals. Existing testing methods can only measure a small portion of these signals directly using standard instruments. The vast majority of system inputs and outputs are bus-type, VDT, and other signals. Analysis of these signals can only be performed by collecting them and then processing and analyzing the data to obtain test results. Both methods involve frequent wiring and a large amount of data processing, often requiring six months or even longer to complete the frequency characteristic test of the flight control system. Summary of the Invention

[0006] This invention provides a multifunctional frequency characteristic testing system and method. Addressing the limitations of existing frequency characteristic testing methods, as well as the problems of numerous test parameters, complex wiring, limited testing means, long test implementation time, and heavy data analysis workload in fly-by-wire flight control systems, this invention employs computer control and real-time simulation technology to expand the application scenarios of traditional frequency characteristic testing, reduce the complexity of wiring work, shorten test preparation and implementation time, and improve test efficiency.

[0007] The first aspect of this invention provides a multifunctional frequency response testing system, comprising: a control computer 1, a real-time simulator 2, a multifunctional I / O board 3, a dynamic signal analyzer 5, and a matrix switcher 6; wherein, The control computer 1 is equipped with frequency response test and control software, which is connected to the real-time simulator 2 via an Ethernet interface. The real-time simulator 2 communicates with the dynamic signal analyzer 5. The control computer 1 is used to send control commands to the real-time simulator 2, and the real-time simulator 2 configures and controls the parameters of the dynamic signal analyzer 6 according to the control commands. The multi-functional I / O board 3 is connected to the dynamic signal analyzer 5 and is used to acquire the sweep frequency excitation signal generated by the dynamic signal analyzer 5 in real time and convert it into the input signal of the test system and input it into the test system through the matrix switcher 6; it is also used to acquire, analyze, calculate and convert the output signal of the test system in real time through the matrix switcher 6 and connect it to the analysis channel of the dynamic signal analyzer 5. The frequency response test control software sets up the frequency sweep mode, automatically performs signal conversion, switches the frequency sweep line through the matrix switcher 6, sets the parameters of the frequency sweeper, and stores the frequency sweep results. For signals that need to be calculated and analyzed, the system functions are expanded by loading various mathematical models and control models into the real-time simulation system software running on the real-time simulator 2.

[0008] Optionally, a control computer 1 is used to issue control commands and receive status data; the control software has functions such as signal definition ICD simulation configuration, line switching configuration, data recording, and result analysis. Among them, the line switching configuration function uses software logic to lock the signal input and output to prevent accidental short circuits and erroneous operations of the signal lines.

[0009] Optionally, the real-time simulator 2 is used to configure and control the parameters of dynamic signal instruments; The real-time simulator 2 deploys simulation management software to manage the real-time simulation cycle, manage and deploy simulation models, realize the superposition, fusion and conversion processing of specified signals, and realize frequency characteristic testing in a semi-physical simulation environment.

[0010] Optional, the multi-functional I / O board 3 includes: analog signal acquisition / simulation board, bus acquisition / simulation card, and fiber optic reflection memory card; The analog acquisition card acquires the frequency sweep excitation signal of the dynamic signal analyzer, converts it into the input signal of the test system through the bus emulation card and analog emulation card, and injects it into the test system. At the same time, it acquires the output signal of the test system or reads the system output signal on the real-time network through the reflective memory card and converts it into an analog signal through the analog signal emulation card, and connects it to the analysis channel of the dynamic signal analyzer 5 to carry out frequency characteristic testing.

[0011] Optionally, the multi-functional frequency response testing system also includes: FPGA multi-functional card 4, which can be programmed to realize the conversion and simulation of special analog signals, especially for the simulation of LVDT and RVDT input signals of fly-by-wire flight control systems, the simulation of special differential signals, and the signal conversion function of system output.

[0012] Optionally, the matrix switcher 6 uses a relay matrix card for arbitrary many-to-many switching, enabling arbitrary connection and disconnection of lines; the 16×16 connection combination uses a BNC socket for external interfaces, matching standard instrument interfaces; the input and output locking settings of the control computer software are configured to prevent short-circuit faults during cable switching by controlling the line switching configuration.

[0013] Optionally, the dynamic signal analyzer 5 serves as an analysis and processing device for the sweep frequency excitation signal generator and the system output signal, receiving control and configuration commands from the real-time simulator.

[0014] A second aspect of the present invention provides a multifunctional frequency characteristic testing method, which is implemented using the multifunctional frequency characteristic testing system as described in any one of the first aspects.

[0015] This invention provides a multifunctional frequency characteristic testing system and method, which, compared with the prior art, has the following advantages: 1) Wide range of applicable scenarios: By configuring rich I / O interface cards, it covers various inputs of various systems, and the application scenarios cover industries such as aviation, aerospace, and automobile.

[0016] 2) The control interface is simple and graphical. The test personnel can switch test circuits, configure parameters, and control instruments by operating the computer mouse.

[0017] 3) Computer control is employed, and line switching and signal injection can be automatically controlled, enabling automated testing, shortening testing time, and improving testing efficiency. Simultaneously, it achieves automatic data saving, automatic result processing, and automatic plotting and saving of amplitude-frequency and phase-frequency curves, greatly enhancing testing efficiency.

[0018] 4) Good expandability: The system hardware has good expandability. By adding simulation boards with corresponding functions, more types of control system frequency characteristic tests can be realized. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the system's functional composition. Figure 2 This is a diagram of the matrix switching control software interface; Figure 3 This is the interface of the frequency sweep control software; Explanation of reference numerals in the attached figures: 1-Main control computer, 2-Real-time emulator, 3-Multi-function I / O board, 4-FPGA card, 5-Dynamic signal analyzer, 6-Matrix switcher; 1-1 shows the interface of the matrix switching control software, which features row and column locking, and switching can be done by clicking the mouse.

[0021] Figures 1-2 show the frequency sweep control software interface, which includes functions such as frequency sweep mode, frequency sweep parameter settings, automatic data saving, and real-time Bode plot drawing. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0024] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0026] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0028] This invention employs computer control and simulation technology to build a real-time simulation system. The I / O interface acquires the sweep frequency excitation signal from the standard instrument in real time and converts it into the input signal type of the tested system. It also acquires, analyzes, and processes the output signal of the tested system in real time, and connects it to the analysis channel of the standard instrument via digital-to-analog conversion through the I / O board. The real-time simulation system sets an appropriate simulation cycle according to the control step size of the test subject to ensure the real-time performance of the entire system and to prevent distortion of test results.

[0029] The system is also designed with a matrix switcher. For the test system with multiple inputs and multiple outputs, the programmable matrix switcher can automatically switch the frequency sweep lines. More than 30 lines can be connected in one wiring operation, avoiding frequent wiring in the test and reducing the risk of human error.

[0030] The system employs automatic software control, where the sweep frequency conditions are set via software, and the program automatically performs operations such as signal conversion, line switching, sweep frequency instrument parameter setting, and sweep frequency result storage. For signals that require calculation and analysis, various mathematical and control models are loaded into the real-time simulation system software to expand the system's functionality.

[0031] The system mainly consists of a control computer 1, a real-time simulator 2, a multi-functional I / O board 3, an FPGA multi-functional card 4, a dynamic signal analyzer 5, and a matrix switcher 6.

[0032] 1) Control computer The control computer serves as the control center for frequency testing. It utilizes a general-purpose industrial computer or workstation, equipped with a monitor, mouse, and keyboard, and deploys frequency response testing control software. It connects to a real-time simulator via an Ethernet interface for issuing control commands and receiving status data. The control software includes functions such as signal definition (ICD) simulation configuration, line switching configuration, data logging, result analysis, and simulation model management. The line switching configuration software module uses software logic locking of signal inputs and outputs to prevent accidental short circuits and other malfunctions in the signal lines.

[0033] 2) Real-time simulator The real-time simulation computer uses a standard PXI / PCI chassis, equipped with a PXI / PCI controller, and runs on Linux RT or LabVIEW RT operating systems. The real-time simulator communicates with the dynamic signal analyzer via the instrument's internal serial port to configure and control the instrument parameters.

[0034] The real-time simulator software deploys simulation management software to manage the real-time simulation cycle, manage and deploy simulation models, and perform processing such as superposition, fusion, and conversion of specified signals to achieve frequency characteristic testing in a semi-physical simulation environment.

[0035] The real-time simulation computer uses a standard PXI / PCI chassis, equipped with a PXI / PCI controller, and runs on Linux RT or LabVIEW RT operating systems. The real-time simulator communicates with the dynamic signal analyzer via the instrument's internal serial port to configure and control the instrument parameters.

[0036] The real-time simulator software deploys simulation management software to manage the real-time simulation cycle, manage and deploy simulation models, and perform processing such as superposition, fusion, and conversion of specified signals to achieve frequency characteristic testing in a semi-physical simulation environment.

[0037] 3) Multifunctional I / O board The multi-functional I / O board mainly includes high-speed analog signal acquisition / simulation boards, bus acquisition / simulation cards, and fiber optic reflection memory cards. The analog signal acquisition card acquires the frequency sweep excitation signal from the dynamic signal analyzer, converts it into input signals for the system under test (SUT) via bus simulation cards, analog simulation cards, or FPGA cards, and injects it into the SUT. Simultaneously, it acquires the output signals of the SUT via I / O cards or reads system output signals from the real-time network via reflection memory cards, converts them into analog signals via analog signal simulation cards, and connects them to the analysis channel of the dynamic signal analyzer for frequency response testing.

[0038] 4) FPGA multi-function card FPGA multifunction cards enable the simulation of special analog signal conversions through programming, particularly for the simulation of LVDT and RVDT input signals of fly-by-wire flight control systems, the simulation of special differential signals, and the signal conversion function of system outputs.

[0039] 5) Matrix switcher The matrix switcher uses a relay matrix card for arbitrary many-to-many switching, enabling arbitrary connection and disconnection of lines. It features a 16×16 connection configuration and uses BNC sockets for external interfaces, compatible with standard instrument interfaces, allowing for quick and easy device connection via simple plug-and-play. The control software's input and output locking settings prevent short-circuit faults during cable switching by configuring line switching. In the experiment, 30 signals could be analyzed in a single wiring operation, avoiding frequent wiring operations.

[0040] 6) Dynamic signal analyzer The dynamic signal analyzer uses a mature off-the-shelf product as a sweep frequency excitation signal generator and a device for analyzing and processing system output signals. It connects to the real-time simulator through its built-in control interface (serial port) to receive control and configuration commands from the real-time simulator.

[0041] like Figure 1As shown, the multifunctional frequency response testing system mainly consists of a control computer, a real-time simulator, a multifunctional I / O card, an FPGA card, a dynamic signal analyzer, and a matrix switcher. The main control computer 1 is a commercial computer, equipped with control software and the real-time simulation management software VeriStand. This allows for programming and control of the dynamic signal analyzer, real-time simulator, multifunctional I / O board, and FPGA card. The software includes functions for parsing and plotting frequency sweep data, and automatically saves the sweep results. The real-time simulator 2 uses a PXIe 1085 chassis, is equipped with a PXIe 8880 controller, and runs LabVIEW RT. Its real-time operating cycle is set to 1kHz. VeriStand manages the simulation model and bus signal ICD configuration. The multifunctional I / O board 3 uses a PXI 6225 analog acquisition card, a PXIe 6738 analog simulation card, and a VMIC 5565 reflective memory card. These I / O cards cover the signal interfaces of various systems and equipment on the iron bird test platform, controlling the data conversion and transmission delays of each system to within 1ms. FPGA multifunction card 4, using PXIe-7856R, simulates differential and LVDT signals through programming, enabling frequency sweep simulation of fly-by-wire flight control input signals. Dynamic signal analyzer, using Solartron 1250E, communicates with the real-time simulator via IEEE 488 serial port, enabling linear, logarithmic, and fixed-frequency sweeps. During experiments, test data is synchronously uploaded to the control computer, achieving real-time plotting and automatic saving of results. Matrix switcher 6, using PXIe 8234 and matrix relay card, uses a BNC interface, allowing for approximately 30-channel frequency sweep testing after a single wiring operation.

[0042] In the iron bird test of a large amphibious aircraft, the frequency characteristics of the servo loop of the flight control system were tested. The frequency sweep excitation from the dynamic signal analyzer was acquired in real time via the analog input / output interface of a real-time simulation computer. This excitation was then converted into LVDT (Low-Level Digital Transmission) signals for aircraft operation commands via a multi-functional FPGA and injected into the servo control system. The servo actuation displacement signals from the real-time network were read, converted into analog signals, and connected to the analysis channel of the dynamic signal analyzer, thus completing the frequency sweep test of the servo loop. Only one wiring check was required before the process. During the test, an automatic switching module was used to achieve automatic line switching, greatly reducing the test time and expanding the frequency sweep scenarios that standard instruments could not perform.

[0043] Meanwhile, in the flight control stability reserve test of a large amphibious aircraft, the real-time simulation computer of this invention reads the aircraft attitude and corresponding flight control system data on the real-time network, and performs superposition and coupling calculations on different data. The results are then input into a dynamic signal analyzer for synchronous analysis. Through automatic test control and automatic data saving, the test time is greatly shortened, reducing the previous 6 months of test time to 1 month.

[0044] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A multifunctional frequency response testing system, characterized in that, include: The control computer (1), real-time simulator (2), multi-functional I / O board (3), dynamic signal analyzer (5), and matrix switcher (6) are included; among them, Frequency characteristic test control software is deployed on the control computer (1), which is connected to the real-time simulator (2) via an Ethernet interface. The real-time simulator (2) communicates with the dynamic signal analyzer (5). The control computer (1) is used to send control commands to the real-time simulator (2), and the real-time simulator (2) configures and controls the parameters of the dynamic signal analyzer (6) according to the control commands; The multi-functional I / O board (3) is connected to the dynamic signal analyzer (5) and is used to collect the sweep frequency excitation signal generated by the dynamic signal analyzer (5) in real time and convert it into the input signal of the test system and input it into the test system through the matrix switcher (6); it is also used to collect, analyze, calculate and convert the output signal of the test system in real time through the matrix switcher (6) and connect it to the analysis channel of the dynamic signal analyzer (5); The frequency response test control software sets up the frequency sweeping mode, automatically performs signal conversion, realizes frequency sweeping line switching through matrix switcher (6), sets frequency sweeping instrument parameters, and stores frequency sweeping results; for signals that need to be calculated and analyzed, various mathematical models and control models are loaded into the real-time simulation system software running on the real-time simulator (2) to expand the system functions.

2. The multifunctional frequency response testing system according to claim 1, characterized in that, The control computer (1) is used to issue control commands and receive status data; the control software has functions such as signal definition ICD simulation configuration, line switching configuration, data recording, and result analysis. Among them, the line switching configuration function uses software logic to lock the signal input and output to prevent accidental short circuits and erroneous operations of the signal lines.

3. The multifunctional frequency characteristic testing system according to claim 1, characterized in that, The real-time simulator (2) is used to configure and control the parameters of dynamic signal instruments; The real-time simulator (2) deploys simulation management software to manage the real-time simulation cycle, manage and deploy simulation models, realize the superposition, fusion and conversion processing of specified signals, and realize frequency characteristic testing in a semi-physical simulation environment.

4. The multifunctional frequency response testing system according to claim 1, characterized in that, The multi-functional I / O board (3) includes: analog acquisition / simulation board, bus acquisition / simulation card, and fiber optic reflection memory card; The analog acquisition card acquires the frequency sweep excitation signal of the dynamic signal analyzer, converts it into the input signal of the test system through the bus simulation card and the analog simulation card, and injects it into the test system; at the same time, it acquires the output signal of the test system or reads the system output signal on the real-time network through the reflective memory card and converts it into an analog signal through the analog signal simulation card, and connects it to the analysis channel of the dynamic signal analyzer (5) to carry out frequency characteristic testing.

5. The multifunctional frequency response testing system according to claim 1, characterized in that, Also includes: The FPGA multifunction card (4) realizes the conversion simulation of special analog signals through programming, especially the simulation of LVDT and RVDT input signals of fly-by-wire flight control system, the simulation of special differential signals, and the signal conversion function of system output.

6. The multifunctional frequency response testing system according to claim 1, characterized in that, The matrix switcher (6) uses a relay matrix card for arbitrary switching between many and many, enabling arbitrary connection and disconnection of lines; the 16×16 connection combination uses a BNC socket for external interfaces, which are compatible with standard instrument interfaces; the input and output locking settings of the control computer software are configured to prevent short circuit faults during cable switching by controlling the line switching configuration of the control software.

7. The multifunctional frequency response testing system according to claim 1, characterized in that, The dynamic signal analyzer (5) serves as an analysis and processing device for the frequency sweep excitation signal generator and the system output signal, and receives control and configuration commands from the real-time simulator.

8. A multifunctional frequency response testing method, characterized in that, The multifunctional frequency response testing system as described in any one of claims 1-7 is used.

Images