Method for testing electrical performance of full-aircraft low-frequency cable network of aircraft

Abstract

The invention discloses a method for testing the electrical performance of a full-aircraft low-frequency cable network of an aircraft, and relates to the technical field of low-frequency cable performance testing, the full-aircraft low-frequency cable network of the aircraft is subjected to initialization detection, and the initialization detection comprises the on-resistance test of the cable network, the short-circuit test of the cable network and the insulation resistance test of the cable network; the high-precision resistance test is carried out according to the wiring relation with the requirement for the resistance precision in the whole-machine cable network, and the high-precision resistance test is carried out by switching the single-double combination of an initialization test channel into a four-wire test channel. According to the invention, a full-aircraft low-frequency cable network of an aircraft can be fully covered, comprehensive detection of the electrical performance of the cable network is realized, and the test efficiency and accuracy are effectively improved; by means of an advanced fault diagnosis algorithm, potential faults in a cable network can be quickly and accurately diagnosed, accurate positioning is carried out, maintenance personnel can repair the faults in time conveniently, and the reliability of an aircraft electrical system is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of low-frequency cable performance testing technology, and in particular to a method for testing the electrical performance of a low-frequency cable network throughout an aircraft. Background Technology

[0002] The low-frequency cable network of an aircraft is a key component of the aircraft's electrical system, used to transmit various control signals, distribute power, etc., and its electrical performance is directly related to the safe operation of the aircraft.

[0003] Currently, aircraft cable network testing often employs segmented or partial testing methods, which makes it difficult to comprehensively and accurately reflect the electrical performance of the entire aircraft cable network under actual operating conditions.

[0004] Existing testing methods are inefficient and cannot effectively detect potential electrical faults. These methods primarily rely on manual testing using various equipment and instruments to assess the performance of aircraft cable networks. For example, continuity testing uses continuity meters or multimeters, but manual testing of tens of thousands of wires requiring continuity testing is time-consuming. Insulation testing uses insulation meters, but this only covers about 30% of the wires, failing to comprehensively cover the entire aircraft cable network. Most importantly, there is no centralized system to store and analyze all test indicators for unified statistical analysis and data support, making it impossible to intuitively represent the electrical performance of the aircraft cable network. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for testing the electrical performance of a low-frequency cable network throughout an aircraft. The technical solution adopted is as follows: A method for testing the electrical performance of a low-frequency cable network throughout an aircraft, characterized by the following steps: Step 1: Perform initialization testing on the entire low-frequency cable network of the aircraft. The initialization testing includes continuity resistance testing, short-circuit testing, and insulation resistance testing of the cable network. Step 2: Perform high-precision resistance testing on the wiring relationships in the entire machine's cable network that require resistance accuracy. The high-precision resistance test involves switching the initial test channel from single / double combination to a four-wire test channel to perform the high-precision resistance test. Step 3: Send standard test signals to the cable network through a signal source. The standard test signals include sine wave signals and square wave signals of different frequencies and amplitudes. Step 4: The signal receiver receives the signal transmitted through the cable network, and the data acquisition module collects the electrical parameters of the signal, such as amplitude, phase, and frequency, in real time, and transmits the collected data to the control and analysis computer. Step 5: The control and analysis computer analyzes the collected data according to the preset signal transmission performance indicators to determine whether the signal transmission performance of the cable network meets the requirements. Step 6: Based on the collected electrical parameter data, combined with the cable network topology and electrical model, fault location is performed. Fault location is achieved by transmitting a frequency sweep signal and using frequency domain reflection.

[0006] By adopting the above technical solutions, the low-frequency cable network of the entire aircraft can be fully covered, enabling comprehensive testing of the electrical performance of the cable network and effectively improving testing efficiency and accuracy.

[0007] With the help of advanced fault diagnosis algorithms, potential faults in the cable network can be quickly and accurately diagnosed and precisely located, making it easier for maintenance personnel to repair them in a timely manner and greatly improving the reliability of the aircraft electrical system.

[0008] This testing method is versatile and scalable, applicable to low-frequency cable network testing of different aircraft models, and has broad application prospects.

[0009] Optionally, step 7 is also included, whereby the control analysis computer outputs the test results in the form of intuitive charts and curves, and conducts a comprehensive evaluation of the electrical performance of the aircraft's low-frequency cable network based on preset performance indicators and safety standards, generating a detailed test report. The test report includes the signal transmission performance indicators, electromagnetic compatibility indicators, and fault diagnosis results of the cable network.

[0010] Optionally, in step 6, the method for fault location via frequency domain reflection includes the following steps: Step 61, Determine the test frequency range: Select multiple measurement frequency points, each frequency point is limited by the device program according to the usage scenario; Step 62: Calculate the frequency domain characteristics based on the incident sweep frequency signal and the reflected sweep frequency signal. The frequency domain characteristics are displayed as potential and current density. Step 63: Calculate the phase difference between the incident signal and the reflected signal; Step 64: Calculate the position of the reflection point; Step 65: Calculate distance information.

[0011] By adopting the above technical solution, and by selecting multiple measurement frequency points based on the usage scenario through the equipment program, and combining the frequency domain characteristics (potential and current density), phase difference, and other data of the incident and reflected frequency sweep signals, the location and distance information of the reflection point are calculated using a specific formula. This allows for the accurate location of fault points with impedance discontinuities (such as open circuits, short circuits, and poor insulation) in cable networks, avoiding the blindness of traditional manual troubleshooting and significantly shortening the fault location time.

[0012] Compared to existing technologies that can only detect some wires or rely on manual judgment, this method can cover the entire machine's cable network, and has high positioning accuracy. It can directly pinpoint the skin depth and distance of the fault location, providing clear guidance for maintenance.

[0013] Based on the principle of frequency domain reflection, by analyzing the transmission and reflection characteristics of swept-frequency signals at different frequencies, potential faults in cable networks under various operating conditions (such as different signal frequencies, load conditions, etc.) can be detected, including latent faults (such as impedance changes caused by slight insulation aging).

[0014] This solves the problem that existing testing methods are unable to detect potential faults, ensures the stability of cable networks in actual operation, and reduces safety hazards caused by failure to detect faults in a timely manner.

[0015] As one of the core modules of the testing system, the fault location method's test data can be stored in the system database along with data from other modules such as initialization detection and signal transmission performance testing, enabling centralized management and unified analysis of the entire machine's cable network test data.

[0016] This approach avoids the drawbacks of traditional methods where test data are scattered and difficult to correlate and analyze. It allows staff to combine cable network topology and electrical models to comprehensively assess the impact of faults on overall electrical performance, thereby improving the scientific rigor of aircraft electrical system reliability analysis.

[0017] The test frequency range is limited by the device program according to the usage scenario, and can be adapted to the low-frequency cable network of different aircraft models (such as cables of different lengths and materials). It does not require significant adjustments for specific aircraft models and has wide applicability.

[0018] As cable networks become more complex, calculation accuracy can be optimized by increasing the number of measurement frequency points, thus meeting more stringent testing requirements in the future and showing broad application prospects.

[0019] Optionally, in step 62, the formula for calculating the frequency domain characteristics is:

[0020] in For the frequency domain representation of the swept signal, the complex amplitude is expressed at frequency f; in This is the time-domain representation of the swept frequency signal; in It is the Fourier transform kernel function; Where i is the frequency number of the sweep frequency signal.

[0021] Optionally, in step 63, the formula for calculating the phase difference between the incident signal and the reflected signal is:

[0022] in The total phase difference between the incident signal and the reflected signal; in The incident signal frequency; in This represents the one-way geometric distance from the reflecting surface to the reference surface; in The phase velocity of the signal in the conductor; in This is an additional phase correction coefficient.

[0023] Optionally, in step 64, the formula for calculating the position of the reflection point is:

[0024] in The equivalent position coordinates of the reflection point relative to the reference surface; in The wavelength of the signal in the conductor; in The amplitude of the incident signal at the reference plane; in This represents the amplitude of the reflected signal at the reference plane.

[0025] Optionally, in step 65, the formula for calculating the distance information is:

[0026] in This represents the one-way geometric distance from the reflecting surface to the reference surface; in The wavelength of the signal in the conductor; in The amplitude of the incident signal at the reference plane; in This represents the amplitude of the reflected signal at the reference plane.

[0027] An aircraft-wide low-frequency cable network electrical performance testing system is used to implement methods for testing the electrical performance of the aircraft-wide low-frequency cable network. The system includes a human-machine interface module, a control module, an initialization test module, a signal transmission performance test module, a fault diagnosis and location module, and a control and analysis computer. The human-machine interface module controls the execution actions of the initialization test module, the signal transmission performance test module, and the fault diagnosis and location module through the control module. The initialization test module, the signal transmission performance test module, and the fault diagnosis and location module are all communicatively connected to the control and analysis computer. The control and analysis computer analyzes the collected data based on preset signal transmission performance indicators to determine whether the signal transmission performance of the cable network meets the requirements, and performs fault location based on the collected electrical parameter data, combined with the cable network topology and electrical model.

[0028] By adopting the above technical solution, the initialization test module includes the following components: Human-computer interaction module: Used to input information such as the wiring relationships of the aircraft's low-frequency cable network.

[0029] Control module: Receives information from the human-computer interaction module and initiates the testing module to perform various test operations.

[0030] Initialization test module (including continuity resistance test unit, short circuit test unit, and insulation resistance test unit): responsible for specific continuity, short circuit, and insulation resistance tests.

[0031] Database: Stores all conclusions and data generated during the testing process.

[0032] The human-machine interface module is connected to the control module, sending the entered cable network wiring relationships to the control module. The control module is connected to the initialization test module (including each test unit), issuing test commands to it. The initialization test module is connected to the cable network under test, performing continuity, short circuit, and insulation tests. The initialization test module is connected to the database, transmitting test results to the database for storage. First, the wiring relationships of the entire low-frequency cable network are entered into the system through the human-machine interface module, and this information is sent to the control module. Based on the wiring relationships, the control module invokes the initialization test module to perform tests sequentially: Continuity resistance test: Determine the continuity status of each wire based on a preset threshold.

[0033] Low-voltage insulation (short-circuit test): Quickly scan for short circuits between conductors in each channel. If no short circuit is found, perform a high-voltage insulation test to evaluate the insulation performance of the entire cable network.

[0034] After the test is completed, the conclusions are stored in the database to provide a basis for judgment in subsequent tests (such as confirming whether the cable network can be tested later).

[0035] The signal transmission performance test module includes the following components: Control module: Identifies the wiring relationships to be tested, controls channel switching, and starts the test module.

[0036] Channel switching module: responsible for switching the initialization test channel to the signal transmission test channel.

[0037] Signal source: Used to send standard test signals (such as sine waves, square waves, etc. of different frequencies and amplitudes) to the cable network.

[0038] Signal receiver: Receives signals transmitted through a cable network.

[0039] Data acquisition module: Real-time acquisition of electrical parameters such as amplitude, phase, and frequency of signals.

[0040] Analysis and control computer: Analyzes the collected data and determines the signal transmission performance.

[0041] Database: Stores test results.

[0042] The control module is connected to the channel switching module and the signal transmission performance test module respectively, and issues channel switching commands and test start commands.

[0043] The channel switching module is connected to the signal transmission test channel to complete the channel switching operation.

[0044] The signal source is connected to the cable network under test and sends a test signal to it.

[0045] The cable network under test is connected to a signal receiver, and the transmitted signal is received by the receiver.

[0046] The signal receiver is connected to the data acquisition module and transmits the received signal to the acquisition module.

[0047] The data acquisition module is connected to the analysis and control computer, providing the acquired electrical parameters.

[0048] The analysis and control computer is connected to the database, and the test results are stored in the database.

[0049] The control module identifies the wiring relationships requiring signal transmission performance testing (e.g., the 1394 bus of a certain model) through software. Following a specified sequence, the control module controls the channel switching module to switch the corresponding initialization test channel to the signal transmission test channel. After the signal transmission performance test module is activated, the signal source sends a series of standard test signals to the cable network. The signal receiver receives the signals transmitted through the cable network, and the data acquisition module collects parameters such as amplitude, phase, and frequency of the signals in real time and transmits them to the analysis and control computer.

[0050] The analysis and control computer analyzes the data according to preset signal transmission performance indicators (such as signal attenuation rate, phase offset, etc.), determines whether the signal transmission performance of the cable network meets the requirements, and finally stores the test results in the database.

[0051] The fault diagnosis and location module includes the following components: RF sweep signal source: transmits sweep signal.

[0052] Test channel: Transmits the sweep frequency signal to the conductor under test.

[0053] The receiving circuit (including the incident signal receiving unit and the reflected signal receiving unit) receives the incident sweep frequency signal and the reflected sweep frequency signal, respectively.

[0054] Acquisition circuit: Acquires signal data obtained by the receiving circuit.

[0055] Storage unit: Stores the acquired signal data.

[0056] Reflection coefficient calculation module: Calculates the reflection coefficients of the incident and reflected signals.

[0057] Inverse Fourier Transform Module: Performs inverse Fourier transform processing on relevant data.

[0058] Control module: Combining the topology and electrical model of the cable network, it coordinates the entire fault diagnosis and location process.

[0059] An RF sweep frequency signal source is connected to the test channel, transmitting the sweep frequency signal to the conductor under test. The conductor under test is connected to the receiving circuit, where the reflected sweep frequency signal is captured, and the incident signal is also received. The receiving circuit is connected to the acquisition circuit, transmitting the received incident and reflected signals to it. The acquisition circuit is connected to the storage unit, storing the acquired signal data. The storage unit is connected to the reflection coefficient calculation module, providing it with the signal data required for calculation. The reflection coefficient calculation module is connected to the inverse Fourier transform module, transmitting the calculated reflection coefficients for processing. The inverse Fourier transform module is connected to the control module; the processing results, combined with the cable network topology and electrical model, enable fault location.

[0060] Based on the principle of frequency domain reflection (FDR), the specific steps are as follows: Determine the test frequency range: The device program limits multiple measurement frequency points according to the usage scenario.

[0061] An RF sweep frequency signal source transmits a sweep frequency signal, which is transmitted to the conductor under test through a test channel. The receiving circuit receives both the incident and reflected sweep frequency signals. The acquisition circuit collects data from these two signals and stores them in a storage unit. The reflection coefficient calculation module calculates the frequency domain characteristics (displayed as potential and current density) based on the incident and reflected sweep frequency signals, and calculates the phase difference between them. The location and distance of the reflection point are calculated using formulas. Combining the cable network topology and electrical model, and through processing such as inverse Fourier transform, a spatial image is output, enabling precise fault location. The diagnostic conclusions guide personnel in troubleshooting and repair.

[0062] The memory stores test programs designed using the aircraft's overall low-frequency cable network electrical performance test method.

[0063] The computer runs a test program designed using the aircraft's overall low-frequency cable network electrical performance test method and outputs the test results.

[0064] In summary, the present invention has at least one of the following beneficial technical effects: This invention provides a method for testing the electrical performance of the entire low-frequency cable network of an aircraft, which can comprehensively cover the entire low-frequency cable network of the aircraft, realize all-round testing of the electrical performance of the cable network, and effectively improve the testing efficiency and accuracy. With the help of advanced fault diagnosis algorithms, potential faults in the cable network can be quickly and accurately diagnosed and precisely located, making it easier for maintenance personnel to repair them in a timely manner and greatly improving the reliability of the aircraft electrical system. Attached Figure Description

[0065] Figure 1 This is a flowchart illustrating the method for testing the electrical performance of the low-frequency cable network of an aircraft as described in this invention. Figure 2 This is a schematic diagram of the internal components and connection principle of the initialization test module of the aircraft low-frequency cable network electrical performance test system of the present invention; Figure 3 This is a schematic diagram of the internal composition and connection principle of the signal transmission test module of the aircraft low-frequency cable network electrical performance test system of the present invention; Figure 4 This is a schematic diagram of the internal composition and connection principle of the fault diagnosis and location module of the aircraft low-frequency cable network electrical performance testing system of the present invention; Detailed Implementation

[0066] The present invention will be further described in detail below with reference to the accompanying drawings.

[0067] This invention discloses a method for testing the electrical performance of the low-frequency cable network of an aircraft.

[0068] Reference Figures 1-4Example 1: A method for testing the electrical performance of a low-frequency cable network throughout an aircraft, characterized by the following steps: Step 1: Perform initialization testing on the entire low-frequency cable network of the aircraft. The initialization testing includes continuity resistance testing, short-circuit testing, and insulation resistance testing of the cable network. Step 2: Perform high-precision resistance testing on the wiring relationships in the entire machine's cable network that require resistance accuracy. The high-precision resistance test involves switching the initial test channel from single / double combination to a four-wire test channel to perform the high-precision resistance test. Step 3: Send standard test signals to the cable network through a signal source. The standard test signals include sine wave signals and square wave signals of different frequencies and amplitudes. Step 4: The signal receiver receives the signal transmitted through the cable network, and the data acquisition module collects the electrical parameters of the signal, such as amplitude, phase, and frequency, in real time, and transmits the collected data to the control and analysis computer. Step 5: The control and analysis computer analyzes the collected data according to the preset signal transmission performance indicators to determine whether the signal transmission performance of the cable network meets the requirements. Step 6: Based on the collected electrical parameter data, combined with the cable network topology and electrical model, fault location is performed. Fault location is achieved by transmitting a frequency sweep signal and using frequency domain reflection.

[0069] It can comprehensively cover the low-frequency cable network of the entire aircraft, enabling all-round testing of the electrical performance of the cable network, effectively improving testing efficiency and accuracy.

[0070] With the help of advanced fault diagnosis algorithms, potential faults in the cable network can be quickly and accurately diagnosed and precisely located, making it easier for maintenance personnel to repair them in a timely manner and greatly improving the reliability of the aircraft electrical system.

[0071] This testing method is versatile and scalable, applicable to low-frequency cable network testing of different aircraft models, and has broad application prospects.

[0072] Example 2 also includes step 7, whereby the control analysis computer outputs the test results in the form of intuitive charts and curves, and comprehensively evaluates the electrical performance of the aircraft's low-frequency cable network according to preset performance indicators and safety standards, generating a detailed test report. The test report includes the signal transmission performance indicators, electromagnetic compatibility indicators, and fault diagnosis results of the cable network.

[0073] In Example 3, step 6, the method for fault location via frequency domain reflection includes the following steps: Step 61, Determine the test frequency range: Select multiple measurement frequency points, each frequency point is limited by the device program according to the usage scenario; Step 62: Calculate the frequency domain characteristics based on the incident sweep frequency signal and the reflected sweep frequency signal. The frequency domain characteristics are displayed as potential and current density. Step 63: Calculate the phase difference between the incident signal and the reflected signal; Step 64: Calculate the position of the reflection point; Step 65: Calculate distance information.

[0074] By selecting multiple measurement frequency points based on the usage scenario and combining the frequency domain characteristics (potential and current density), phase difference, and other data of the incident and reflected sweep frequency signals, the device program calculates the location and distance information of the reflection point using a specific formula. This enables precise location of fault points with impedance discontinuities in cable networks (such as open circuits, short circuits, and poor insulation), avoiding the blindness of traditional manual troubleshooting and significantly shortening the fault location time.

[0075] Compared to existing technologies that can only detect some wires or rely on manual judgment, this method can cover the entire machine's cable network, and has high positioning accuracy. It can directly pinpoint the skin depth and distance of the fault location, providing clear guidance for maintenance.

[0076] Based on the principle of frequency domain reflection, by analyzing the transmission and reflection characteristics of swept-frequency signals at different frequencies, potential faults in cable networks under various operating conditions (such as different signal frequencies, load conditions, etc.) can be detected, including latent faults (such as impedance changes caused by slight insulation aging).

[0077] This solves the problem that existing testing methods are unable to detect potential faults, ensures the stability of cable networks in actual operation, and reduces safety hazards caused by failure to detect faults in a timely manner.

[0078] As one of the core modules of the testing system, the fault location method's test data can be stored in the system database along with data from other modules such as initialization detection and signal transmission performance testing, enabling centralized management and unified analysis of the entire machine's cable network test data.

[0079] This approach avoids the drawbacks of traditional methods where test data are scattered and difficult to correlate and analyze. It allows staff to combine cable network topology and electrical models to comprehensively assess the impact of faults on overall electrical performance, thereby improving the scientific rigor of aircraft electrical system reliability analysis.

[0080] The test frequency range is limited by the device program according to the usage scenario, and can be adapted to the low-frequency cable network of different aircraft models (such as cables of different lengths and materials). It does not require significant adjustments for specific aircraft models and has wide applicability.

[0081] As cable networks become more complex, calculation accuracy can be optimized by increasing the number of measurement frequency points, thus meeting more stringent testing requirements in the future and showing broad application prospects.

[0082] In Example 4, step 62, the formula for calculating the frequency domain characteristics is:

[0083] in For the frequency domain representation of the swept signal, the complex amplitude is expressed at frequency f; in This is the time-domain representation of the swept frequency signal; in It is the Fourier transform kernel function; Where i is the frequency number of the sweep frequency signal.

[0084] In Example 5, step 63, the formula for calculating the phase difference between the incident signal and the reflected signal is:

[0085] in The total phase difference between the incident signal and the reflected signal; in The incident signal frequency; in This represents the one-way geometric distance from the reflecting surface to the reference surface; in The phase velocity of the signal in the conductor; in This is an additional phase correction coefficient.

[0086] In Example 6, step 64, the formula for calculating the position of the reflection point is:

[0087] in The equivalent position coordinates of the reflection point relative to the reference surface; in The wavelength of the signal in the conductor; in The amplitude of the incident signal at the reference plane; in This represents the amplitude of the reflected signal at the reference plane.

[0088] In Example 7, step 65, the formula for calculating distance information is:

[0089] in This represents the one-way geometric distance from the reflecting surface to the reference surface; in The wavelength of the signal in the conductor; in The amplitude of the incident signal at the reference plane; in This represents the amplitude of the reflected signal at the reference plane.

[0090] Example 8: Aircraft Low-Frequency Cable Network Electrical Performance Testing System. This system is used to implement a method for testing the electrical performance of an aircraft's low-frequency cable network. The system includes a human-machine interface module, a control module, an initialization test module, a signal transmission performance test module, a fault diagnosis and location module, and a control and analysis computer. The human-machine interface module controls the execution actions of the initialization test module, the signal transmission performance test module, and the fault diagnosis and location module through the control module. The initialization test module, the signal transmission performance test module, and the fault diagnosis and location module are all communicatively connected to the control and analysis computer. The control and analysis computer analyzes the collected data based on preset signal transmission performance indicators to determine whether the signal transmission performance of the cable network meets the requirements. Based on the collected electrical parameter data, combined with the cable network's topology and electrical model, it performs fault location.

[0091] The initialization test module includes the following components: Human-computer interaction module: Used to input information such as the wiring relationships of the aircraft's low-frequency cable network.

[0092] Control module: Receives information from the human-computer interaction module and initiates the testing module to perform various test operations.

[0093] Initialization test module (including continuity resistance test unit, short circuit test unit, and insulation resistance test unit): responsible for specific continuity, short circuit, and insulation resistance tests.

[0094] Database: Stores all conclusions and data generated during the testing process.

[0095] The human-machine interface module is connected to the control module, sending the entered cable network wiring relationships to the control module. The control module is connected to the initialization test module (including each test unit), issuing test commands to it. The initialization test module is connected to the cable network under test, performing continuity, short circuit, and insulation tests. The initialization test module is connected to the database, transmitting test results to the database for storage. First, the wiring relationships of the entire low-frequency cable network are entered into the system through the human-machine interface module, and this information is sent to the control module. Based on the wiring relationships, the control module invokes the initialization test module to perform tests sequentially: Continuity resistance test: Determine the continuity status of each wire based on a preset threshold.

[0096] Low-voltage insulation (short-circuit test): Quickly scan for short circuits between conductors in each channel. If no short circuit is found, perform a high-voltage insulation test to evaluate the insulation performance of the entire cable network.

[0097] After the test is completed, the conclusions are stored in the database to provide a basis for judgment in subsequent tests (such as confirming whether the cable network can be tested later).

[0098] The signal transmission performance test module includes the following components: Control module: Identifies the wiring relationships to be tested, controls channel switching, and starts the test module.

[0099] Channel switching module: responsible for switching the initialization test channel to the signal transmission test channel.

[0100] Signal source: Used to send standard test signals (such as sine waves, square waves, etc. of different frequencies and amplitudes) to the cable network.

[0101] Signal receiver: Receives signals transmitted through a cable network.

[0102] Data acquisition module: Real-time acquisition of electrical parameters such as amplitude, phase, and frequency of signals.

[0103] Analysis and control computer: Analyzes the collected data and determines the signal transmission performance.

[0104] Database: Stores test results.

[0105] The control module is connected to the channel switching module and the signal transmission performance test module respectively, and issues channel switching commands and test start commands.

[0106] The channel switching module is connected to the signal transmission test channel to complete the channel switching operation.

[0107] The signal source is connected to the cable network under test and sends a test signal to it.

[0108] The cable network under test is connected to a signal receiver, and the transmitted signal is received by the receiver.

[0109] The signal receiver is connected to the data acquisition module and transmits the received signal to the acquisition module.

[0110] The data acquisition module is connected to the analysis and control computer, providing the acquired electrical parameters.

[0111] The analysis and control computer is connected to the database, and the test results are stored in the database.

[0112] The control module identifies the wiring relationships requiring signal transmission performance testing (e.g., the 1394 bus of a certain model) through software. Following a specified sequence, the control module controls the channel switching module to switch the corresponding initialization test channel to the signal transmission test channel. After the signal transmission performance test module is activated, the signal source sends a series of standard test signals to the cable network. The signal receiver receives the signals transmitted through the cable network, and the data acquisition module collects parameters such as amplitude, phase, and frequency of the signals in real time and transmits them to the analysis and control computer.

[0113] The analysis and control computer analyzes the data according to preset signal transmission performance indicators (such as signal attenuation rate, phase offset, etc.), determines whether the signal transmission performance of the cable network meets the requirements, and finally stores the test results in the database.

[0114] The fault diagnosis and location module includes the following components: RF sweep signal source: transmits sweep signal.

[0115] Test channel: Transmits the sweep frequency signal to the conductor under test.

[0116] The receiving circuit (including the incident signal receiving unit and the reflected signal receiving unit) receives the incident sweep frequency signal and the reflected sweep frequency signal, respectively.

[0117] Acquisition circuit: Acquires signal data obtained by the receiving circuit.

[0118] Storage unit: Stores the acquired signal data.

[0119] Reflection coefficient calculation module: Calculates the reflection coefficients of the incident and reflected signals.

[0120] Inverse Fourier Transform Module: Performs inverse Fourier transform processing on relevant data.

[0121] Control module: Combining the topology and electrical model of the cable network, it coordinates the entire fault diagnosis and location process.

[0122] An RF sweep frequency signal source is connected to the test channel, transmitting the sweep frequency signal to the conductor under test. The conductor under test is connected to the receiving circuit, where the reflected sweep frequency signal is captured, and the incident signal is also received. The receiving circuit is connected to the acquisition circuit, transmitting the received incident and reflected signals to it. The acquisition circuit is connected to the storage unit, storing the acquired signal data. The storage unit is connected to the reflection coefficient calculation module, providing it with the signal data required for calculation. The reflection coefficient calculation module is connected to the inverse Fourier transform module, transmitting the calculated reflection coefficients for processing. The inverse Fourier transform module is connected to the control module; the processing results, combined with the cable network topology and electrical model, enable fault location.

[0123] Based on the principle of frequency domain reflection (FDR), the specific steps are as follows: Determine the test frequency range: The device program limits multiple measurement frequency points according to the usage scenario.

[0124] An RF sweep frequency signal source transmits a sweep frequency signal, which is transmitted to the conductor under test through a test channel. The receiving circuit receives both the incident and reflected sweep frequency signals. The acquisition circuit collects data from these two signals and stores them in a storage unit. The reflection coefficient calculation module calculates the frequency domain characteristics (displayed as potential and current density) based on the incident and reflected sweep frequency signals, and calculates the phase difference between them. The location and distance of the reflection point are calculated using formulas. Combining the cable network topology and electrical model, and through processing such as inverse Fourier transform, a spatial image is output, enabling precise fault location. The diagnostic conclusions guide personnel in troubleshooting and repair.

[0125] Example 9: Memory, storing test programs designed using the aircraft-wide low-frequency cable network electrical performance test method.

[0126] Example 10: The computer runs a test program designed using the aircraft's whole-aircraft low-frequency cable network electrical performance test method and outputs the test results.

[0127] The following specific embodiments illustrate the implementation principle of the present invention: Taking a certain type of aircraft as an example, a test system was built. The WT-200ZY electrical network test platform was selected as the base, which includes the human-machine interaction module, control module, initialization test channel module, high-precision resistance test module, signal transmission performance test module, fault diagnosis and location module, and channel switching module required for testing.

[0128] Test procedure implementation: Cable network initialization testing: Initialization testing is performed using the initialization test module in the WT-200ZY electrical network testing platform. Specifically, the pre-prepared wiring relationship of the entire low-frequency cable network is first entered into the system's human-machine interface module and sent to the control module. The control module then activates the test module to perform a continuity resistance test based on the wiring relationship, determining the continuity of each conductor in the low-frequency cable network according to the set threshold. Next, a low-voltage insulation (short-circuit test) is performed by quickly scanning for short circuits between conductors in each channel. If no short circuits are found, a high-voltage insulation test is performed. The insulation test indicators display the insulation performance of the entire cable network. After the test is completed, the test results are saved in the database.

[0129] Signal transmission performance test: Taking the 1394 bus test of a certain model as an example, the control module software first identifies the wiring relationship that needs to be tested on the 1394 bus, switches the corresponding initialization test channel to the signal transmission test channel in the specified order, starts the signal transmission test module to perform signal transmission performance test, and saves the test results in the database.

[0130] Fault diagnosis and location: Based on the collected electrical parameter data, combined with the cable network topology and electrical model, the FDR test module performs fault diagnosis on the conductors that need and meet the test requirements. The diagnosis results will guide the staff to troubleshoot and repair the faults.

[0131] Test Result Output and Evaluation: The computer control and analysis system outputs the test results in the form of tables, charts, or curves, generating a detailed test report. The test report includes all information on the cable network's continuity resistance, precision resistance, insulation resistance, signal transmission packet loss rate, bit error rate, delay, and fault diagnosis. Based on the test report, personnel conduct targeted inspections and repairs to ensure that the electrical performance of the aircraft's entire low-frequency cable network meets requirements.

[0132] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for testing the electrical performance of a low-frequency cable network throughout an aircraft, characterized in that, Includes the following steps: Step 1: Perform initialization testing on the entire low-frequency cable network of the aircraft. The initialization testing includes continuity resistance testing, short-circuit testing, and insulation resistance testing of the cable network. Step 2: Perform high-precision resistance testing on the wiring relationships in the entire machine's cable network that require resistance accuracy. The high-precision resistance test involves switching the initial test channel from single / double combination to a four-wire test channel to perform the high-precision resistance test. Step 3: Send standard test signals to the cable network through a signal source. The standard test signals include sine wave signals and square wave signals of different frequencies and amplitudes. Step 4: The signal receiver receives the signal transmitted through the cable network, and the data acquisition module collects the amplitude, phase, and frequency electrical parameters of the signal in real time, and transmits the collected data to the control and analysis computer. Step 5: The control and analysis computer analyzes the collected data according to the preset signal transmission performance indicators to determine whether the signal transmission performance of the cable network meets the requirements. Step 6: Based on the collected electrical parameter data, combined with the cable network topology and electrical model, fault location is performed. Fault location is achieved by transmitting a frequency sweep signal and using frequency domain reflection.

2. The method for testing the electrical performance of the aircraft's low-frequency cable network according to claim 1, characterized in that: It also includes step 7, where the control analysis computer outputs the test results in the form of intuitive charts and curves, and conducts a comprehensive evaluation of the electrical performance of the aircraft's low-frequency cable network based on preset performance indicators and safety standards, generating a detailed test report. The test report includes the signal transmission performance indicators, electromagnetic compatibility indicators, and fault diagnosis results of the cable network.

3. The method for testing the electrical performance of the aircraft's low-frequency cable network according to claim 2, characterized in that: Step 6, the method for fault location via frequency domain reflection, includes the following steps: Step 61, Determine the test frequency range: Select multiple measurement frequency points, each frequency point is limited by the device program according to the usage scenario; Step 62: Calculate the frequency domain characteristics based on the incident sweep frequency signal and the reflected sweep frequency signal. The frequency domain characteristics are displayed as potential and current density. Step 63: Calculate the phase difference between the incident signal and the reflected signal; Step 64: Calculate the position of the reflection point; Step 65: Calculate distance information.

4. The method for testing the electrical performance of the aircraft's low-frequency cable network according to claim 3, characterized in that: In step 62, the formula for calculating the frequency domain characteristics is: ； in For the frequency domain representation of the swept signal, the complex amplitude is expressed at frequency f; in This is the time-domain representation of the swept frequency signal; in It is the Fourier transform kernel function; Where i is the frequency number of the sweep frequency signal.

5. The method for testing the electrical performance of the aircraft's low-frequency cable network according to claim 4, characterized in that: In step 63, the formula for calculating the phase difference between the incident and reflected signals is: ; in The total phase difference between the incident signal and the reflected signal; in The incident signal frequency; in This represents the one-way geometric distance from the reflecting surface to the reference surface; in The phase velocity of the signal in the conductor; in This is an additional phase correction coefficient.

6. The method for testing the electrical performance of the aircraft's low-frequency cable network according to claim 5, characterized in that: In step 64, the formula for calculating the position of the reflection point is: ； in The equivalent position coordinates of the reflection point relative to the reference surface; in The wavelength of the signal in the conductor; in The amplitude of the incident signal at the reference plane; in This represents the amplitude of the reflected signal at the reference plane.

7. The method for testing the electrical performance of the aircraft's low-frequency cable network according to claim 6, characterized in that: In step 65, the formula for calculating distance information is: ； in This represents the one-way geometric distance from the reflecting surface to the reference surface; in The wavelength of the signal in the conductor; in The amplitude of the incident signal at the reference plane; in This represents the amplitude of the reflected signal at the reference plane.

8. An aircraft-wide low-frequency cable network electrical performance testing system, characterized in that: The system for implementing the aircraft-wide low-frequency cable network electrical performance testing method according to any one of claims 1-7 includes a human-machine interaction module, a control module, an initialization test module, a signal transmission performance test module, a fault diagnosis and location module, and a control analysis computer. The human-machine interaction module controls the execution actions of the initialization test module, the signal transmission performance test module, and the fault diagnosis and location module through the control module. The initialization test module, the signal transmission performance test module, and the fault diagnosis and location module are all communicatively connected to the control analysis computer. The control analysis computer analyzes the collected data based on preset signal transmission performance indicators, determines whether the signal transmission performance of the cable network meets the requirements, and performs fault location based on the collected electrical parameter data, combined with the cable network topology and electrical model.

9. A memory, characterized in that: The storage uses the test program designed according to the test method for electrical performance testing of the low-frequency cable network of the entire aircraft as described in any one of claims 1-7.

10. A computer, characterized in that: The test program designed using the test method for testing the electrical performance of the low-frequency cable network of the entire aircraft as described in any one of claims 2-7 outputs the test results.

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