A method for testing and diagnosing a nose wheel steering system of an aircraft

Abstract

The present application belongs to the field of testability, and relates to a kind of test diagnosis method of aircraft nose wheel turning system, comprising the following steps: step 1: structure level analysis: carry out aircraft nose wheel turning system structure level analysis;Step 2: fault mode analysis: analyze the fault mode information of each level;Step 3: fault mode and test analysis: determine the measurement parameters required for each fault mode, test point and applicable test method;Step 4: carry out preliminary test diagnosis scheme design, preliminarily determine the layout of test point, and establish the correlation model of fault mode and test;Step 5: carry out testability design evaluation work, get evaluation result, if accept evaluation result, then turn to step 6;If not, if it involves hardware improvement, turn to step 1, if not, turn to step 3;Step 6: test diagnosis design implementation: build aircraft nose wheel turning system test hardware platform, realize the test diagnosis of aircraft nose wheel turning system.

Description

Technical Field

[0001] This invention patent relates to a testing and diagnostic method for an aircraft nose wheel steering system, belonging to the field of testing. Background Technology

[0002] Traditional system-level testing and diagnosis relies heavily on experience in designing test parameters, test points, and test implementation methods. This approach fails to establish a correlation between system functions and fault symptoms, making it difficult to meet requirements in terms of test coverage and fault isolation capabilities.

[0003] As the complexity of system-level technologies continues to increase, on the one hand, the fault mechanisms and manifestations at the system level become more complex, especially the intertwining of system integration faults and individual unit faults, resulting in prominent issues in fault detection and isolation; on the other hand, due to the high correlation and high coupling of system components, a positive test and diagnostic method is needed to guide the selection of test points, test parameters, and test implementation methods, thereby improving the fault detection rate and isolation rate and reducing the false alarm rate. Summary of the Invention

[0004] The technical problem to be solved by this invention is that existing system-level testing and diagnosis methods mostly rely on experience to design test parameters, test points, and test implementation methods. This method cannot establish a correlation between system functions and fault symptoms, and therefore cannot meet the requirements. Therefore, the purpose of this invention is to provide a testing and diagnosis method for an aircraft nose wheel turning system, specifically through an independent sub-card with dual channels to achieve the testing and diagnosis of the aircraft nose wheel turning system.

[0005] Technical solution:

[0006] A test and diagnostic method for an aircraft nose wheel steering system includes the following steps:

[0007] Step 1: Structural hierarchy analysis: Conduct a structural hierarchy analysis of the aircraft's nose wheel steering system;

[0008] Step 2: Failure Mode Analysis: Review the failure mode information at each level analyzed in Step 1 for the aircraft's nose wheel steering system;

[0009] Step 3: Failure Mode and Test Analysis: Based on Step 2, analyze and determine the required measurement parameters, test points, and applicable test methods for each failure mode;

[0010] Step 4: Based on the analysis results of Step 3, conduct preliminary test diagnosis plan design, preliminarily determine the layout of test points, and establish a correlation model between failure modes and tests;

[0011] Step 5: Conduct a test design evaluation and obtain the evaluation results. If the evaluation results are accepted, proceed to Step 6; if they are not accepted and involve hardware improvements, proceed to Step 1; otherwise, proceed to Step 3.

[0012] Step 6: Test and Diagnostic Design Implementation: Generate test and diagnostic design results based on the correlation model in Step 4, build a test hardware platform for the aircraft nose wheel turning system, and realize the test and diagnosis of the aircraft nose wheel turning system.

[0013] Furthermore, step 1 specifically involves obtaining the composition information of the aircraft's nose wheel steering system based on the schematic diagram and functional block diagram of the aircraft's nose wheel steering system, analyzing and determining the system's structural hierarchy, further analyzing the interconnection relationships between the agreed-upon levels of the system, and establishing a system structure diagram from top to bottom.

[0014] Furthermore, in step 1, a hierarchical analysis of the aircraft's nose wheel turning system is conducted, including system-level, LRU-level, and SRU-level hierarchical analysis.

[0015] Furthermore, step 2 specifically involves obtaining all fault mode information based on the composition and structure of the aircraft's nose wheel steering system and the FMECA results.

[0016] Furthermore, the fault mode information in step 2 includes: name, fault mode, fault severity, and fault rate.

[0017] Furthermore, step 3 specifically includes the following steps:

[0018] Step 31): Determine the evolution characteristics of each failure mode based on engineering experience and analysis;

[0019] Step 32): Determine the various symptoms that the fault modes will cause through principle analysis, historical experience, and simulation analysis.

[0020] Step 33): Based on the symptoms of the fault, determine the measurement parameters and test points through judgment and analysis. For electronic products inside the aircraft nose wheel steering control system, voltage, current and resistance signals are used to determine the appropriate test point location in the system to measure the electrical signals. For non-electronic products, determine the sensor type and placement location.

[0021] Furthermore, in step 5, a test design evaluation of the aircraft nose wheel steering system is carried out, and the BIT fault detection rate and fault isolation rate of the aircraft nose wheel steering system are evaluated in turn to obtain the evaluation results.

[0022] Furthermore, in step 6, a test hardware platform is built according to the test and diagnosis scheme for the aircraft nose wheel turning system. The aircraft nose wheel turning system adopts a test hardware platform with an independent daughter card. The test signals collected by the independent daughter card are physically separated from the signals involved in the control. The signals are input into an independent AD sampling module and transmitted to the DSP for processing. If the independent daughter card fails, it will not affect the normal completion of the task by the system control part, thus ensuring the reliability of the aircraft nose wheel turning system task.

[0023] Beneficial effects

[0024] This invention provides a testing and diagnostic method for an aircraft nose wheel steering system. Specifically, it uses an independent sub-card with dual channels to perform the testing and diagnostics of the aircraft nose wheel steering system. The advantages include: 1) Dual-channel independent sub-card monitoring reduces the false alarm rate; 2) Testing and diagnostics are independent of control, avoiding interference; 3) The testing and diagnostic circuit has high integration and high model reuse rate. Attached Figure Description

[0025] Figure 1 This is a flowchart of the test and diagnosis method for the aircraft nose wheel steering system of the present invention;

[0026] Figure 2 This is a structural diagram of the aircraft nose wheel turning system of the present invention;

[0027] Figure 3 This invention relates to a correlation model for the failure modes and testing of the aircraft nose wheel steering system. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of the present invention, and 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.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific examples:

[0030] One embodiment of the present invention is as follows:

[0031] Based on the structural composition of the aircraft's nose wheel steering control system and the fault modes contained in each component, applicable test and diagnostic methods are determined, a correlation model between fault modes and tests is established, and a test and diagnostic layout is implemented. This results in a test and diagnostic method using independent sub-cards and dual-channel mutual monitoring. The flowchart is shown below. Figure 1 As shown. This embodiment proposes a test and diagnosis method for an aircraft nose wheel steering system, which includes the following steps:

[0032] Step 1: Structural hierarchy analysis: Conduct a structural hierarchy analysis of the aircraft's nose wheel turning system, including system level, LRU level, and SRU level;

[0033] Step 2: Failure Mode Analysis: Review the failure mode information of each level of the aircraft nose wheel steering system analyzed in Step 1, including: name, failure mode, failure severity, and failure rate.

[0034] Step 3: Failure Mode and Test Analysis: Based on Step 2, analyze and determine the required measurement parameters, test points, and applicable test methods for each failure mode. The process is as follows: Figure 1 As shown in the dashed box, Step 1): Determine the evolution characteristics of each fault mode based on engineering experience and analysis; Step 2): Determine the various symptoms caused by the fault mode through principle analysis, historical experience, and simulation analysis; Step 3): Based on the fault symptoms, determine the measurement parameters and test points through judgment and analysis. For electronic products inside the aircraft nose wheel steering control system, voltage, current, and resistance signals are used to represent the signals. Determine the appropriate test point location in the system to measure the electrical signals. For non-electronic products, determine the sensor type and placement location.

[0035] Step 4: Based on the analysis results of Step 3, conduct preliminary test diagnosis plan design, preliminarily determine the layout of test points, and establish a correlation model between failure modes and tests;

[0036] Step 5: Conduct a test design evaluation and obtain the evaluation results. If the evaluation results are accepted, proceed to Step 6; if they are not accepted and involve hardware improvements, proceed to Step 1; otherwise, proceed to Step 3.

[0037] Step 6: Test and Diagnostic Design Implementation: Generate test and diagnostic design results based on the correlation model in Step 4, build a test hardware platform for the aircraft nose wheel turning system, and realize the test and diagnosis of the aircraft nose wheel turning system.

[0038] The second embodiment of the present invention is as follows:

[0039] A test and diagnostic method for an aircraft nose wheel steering system is proposed, comprising the following steps:

[0040] Step 1: Structural hierarchy analysis. Based on the schematic diagram and functional block diagram of the aircraft's nose wheel steering system, obtain the component information of the aircraft's nose wheel steering system, analyze and determine the system's structural hierarchy, further analyze the interconnection relationships between the agreed-upon levels of the system, and establish a system structure diagram from top to bottom, such as... Figure 2 As shown;

[0041] Step 2: Failure Mode Analysis: Based on the composition of the aircraft's nose wheel steering system and the FMECA results, obtain all failure mode information, including: name, failure mode, severity, and failure rate. The failure mode table is shown in Table 1.

[0042] Table 1 Fault Mode Summary Table

[0043] Serial Number name Failure Mode Severity Failure rate (1 / h) 1 Drive control unit 5V power supply has no output Ⅲ 1.56E-07 2 Drive control unit 5V power output error Ⅳ 2.35E-07 3 Drive control unit Loss of communication function Ⅲ 1.17E-07

[0044] Step 3: Failure Mode and Test Analysis: After determining the failure mode in Step 2, proceed as follows: Figure 1 The flowchart within the dashed frame is used for fault mode and test analysis. First, based on engineering experience and analysis, the evolution characteristics of each fault mode are determined, and the fault modes are divided into sudden faults and gradual faults. Then, through principle analysis, historical experience, and simulation analysis, the various symptoms caused by the fault modes are determined. After determining the symptoms of the fault modes, the measurement parameters and test points are determined through testing and analysis.

[0045] Step 4: Based on the analysis results of Step 3, design a test and diagnostic scheme for the aircraft's nose wheel steering system, determine the layout of system test points, and establish a correlation model between system failure modes and tests, such as... Figure 3 As shown;

[0046] Step 5: Conduct test design evaluation of the aircraft nose wheel steering system, evaluate the BIT failure detection rate and failure isolation rate of the aircraft nose wheel steering system in turn, and determine whether the evaluation results are acceptable. If the evaluation results are acceptable, proceed to step 6; if not, if the evaluation results involve internal hardware improvements to the aircraft nose wheel steering system, proceed to step 1; if not, proceed to step 3.

[0047] Step 6: Test and Diagnostic Design Implementation: Based on the test and diagnostic plan for the aircraft nose wheel steering system, a test hardware platform is built. The aircraft nose wheel steering system adopts a test hardware platform with an independent daughter card. The test signals collected by the independent daughter card are physically separated from the signals involved in the control. The signals are input to an independent AD sampling module and then transmitted to the DSP for processing. If the independent daughter card fails, it will not affect the normal completion of the task by the system control part, ensuring the reliability of the aircraft nose wheel steering system.

[0048] The third embodiment of the present invention:

[0049] Step 1: Based on the schematic diagram and functional block diagram of the aircraft's nose wheel steering system, establish a system structure diagram, such as... Figure 2 As shown, the aircraft nose wheel turning system mainly consists of two LRUs: a drive control unit and an electric actuator. The drive control unit LRU consists of four SRUs: a control board assembly, a power board assembly, a power board assembly, and a control daughter card assembly. Each SRU has dual channels. The electric actuator LRU consists of four SRUs: a motor assembly, an upper reducer assembly, a lower reducer assembly, and an output terminal assembly. Each SRU has dual channels.

[0050] Step 2: Failure Mode Analysis: Taking the electric actuator of the aircraft nose wheel steering system as an example, the failure modes of the electric actuator are shown in Table 2.

[0051] Table 2. Fault Modes of Electric Actuators

[0052] Serial Number name Failure Mode Severity Failure rate (1 / h) 1 electric actuator No output from the motor Ⅱ 2 electric actuator The motor cannot brake. Ⅲ 3 electric actuator The output gear assembly has no mechanical energy output. Ⅱ 4 electric actuator The mechanical energy output of the output gear assembly is discontinuous. IV 5 electric actuator The output gear assembly has no angle signal output. Ⅲ 6 electric actuator Output gear assembly angle signal error IV

[0053] Step 3: Fault Mode and Test Analysis: After determining the fault mode in Step 2, taking "motor cannot brake" as an example... Figure 1 The flowchart with the dashed box in the middle is used for fault mode and test analysis. Step 1): After analysis, the evolution characteristics of the "motor cannot brake" fault are identified as a sudden fault. Step 2): Through principle analysis of "motor cannot brake", the fault symptom is determined to be that the motor brake cannot brake. Step 3): Based on the fault symptom of "motor brake cannot brake", the parameters that need to be measured are determined to be: motor brake current and motor brake control signal, both of which are detected using the periodic BIT method.

[0054] Step 4: Based on the analysis results of Step 3, taking "motor cannot brake" as an example, arrange the test points: test the braking current at the motor brake drive output terminal, test the braking control signal at the motor brake drive input terminal, and establish a correlation model between the system fault modes and the tests, such as... Figure 3 As shown;

[0055] Step 5: Conduct test design evaluation of the aircraft nose wheel steering system. The evaluation showed that the BIT failure detection rate of the aircraft nose wheel steering system was 96.18%; the failure isolation rate was 92% when isolated to 1 LRU and 100% when isolated to 2 LRUs. Therefore, the test diagnostic solution was accepted.

[0056] Step 6: Test and Diagnostic Design Implementation: Based on the test and diagnostic plan, a test hardware platform using independent daughter cards is adopted. The independent daughter cards are divided into Channel A and Channel B, which are redundant with each other. Each channel performs tests on secondary power supply, tertiary power supply, clutch current, motor brake current, motor brake control signal, bus voltage and current, phase current, motor temperature, IPM temperature, and angle resolver sensor, etc. The test signals collected by the daughter card are physically separated from the signals used in the control. If the independent daughter card fails, it will not affect the normal completion of the system control section, ensuring the reliability of the aircraft's nose wheel turning system.

[0057] This patent has many specific applications. The above description is only a preferred embodiment of this patent and does not limit the implementation method and scope of protection of this patent. For those skilled in the art, the solutions obtained by making equivalent substitutions and obvious changes under the premise of the principle of this patent should be included in the scope of protection of the patent.

Claims

1. A test and diagnostic method for an aircraft nose wheel steering system, characterized in that, Includes the following steps: Step 1: Structural hierarchy analysis: Conduct a structural hierarchy analysis of the aircraft's nose wheel steering system; Step 2: Failure Mode Analysis: Review the failure mode information at each level analyzed in Step 1 for the aircraft's nose wheel steering system; Step 3: Failure Mode and Test Analysis: Based on Step 2, analyze and determine the required measurement parameters, test points, and applicable test methods for each failure mode; Step 4: Based on the analysis results of Step 3, conduct preliminary test diagnosis plan design, preliminarily determine the layout of test points, and establish a correlation model between failure modes and tests; Step 5: Conduct a test design evaluation and obtain the evaluation results. If the evaluation results are accepted, proceed to Step 6; if they are not accepted and involve hardware improvements, proceed to Step 1; otherwise, proceed to Step 3. Step 6: Test and Diagnostic Design Implementation: Generate test and diagnostic design results based on the correlation model in Step 4, build a test hardware platform for the aircraft nose wheel turning system, and realize the test and diagnosis of the aircraft nose wheel turning system.

2. The test and diagnosis method for the aircraft nose wheel steering system according to claim 1, characterized in that, Step 1 specifically involves obtaining the composition information of the aircraft's nose wheel steering system based on the schematic diagram and functional block diagram of the aircraft's nose wheel steering system, analyzing and determining the system's structural hierarchy, further analyzing the interconnection relationships between the agreed-upon levels of the system, and establishing a system structure diagram from top to bottom.

3. The test and diagnosis method for the aircraft nose wheel steering system according to claim 2, characterized in that, In step 1, a hierarchical analysis of the aircraft's nose wheel turning system is conducted, including system-level, LRU-level, and SRU-level hierarchical analysis.

4. The test and diagnosis method for the aircraft nose wheel steering system according to claim 2, characterized in that, Step 2 specifically involves obtaining information on all failure modes based on the composition of the aircraft's nose wheel steering system and the FMECA results.

5. The test and diagnosis method for the aircraft nose wheel steering system according to claim 4, characterized in that, The fault mode information in step 2 includes: name, fault mode, fault severity, and fault rate.

6. The test and diagnosis method for an aircraft nose wheel steering system according to claim 5, characterized in that, Step 3 specifically includes the following steps: Step 31): Determine the evolution characteristics of each failure mode based on engineering experience and analysis; Step 32): Determine the various symptoms that the fault modes will cause through principle analysis, historical experience, and simulation analysis. Step 33): Based on the symptoms of the fault, determine the measurement parameters and test points through judgment and analysis. For electronic products inside the aircraft nose wheel steering control system, voltage, current and resistance signals are used to determine the appropriate test point location in the system to measure the electrical signals. For non-electronic products, determine the sensor type and placement location.

7. The test and diagnosis method for an aircraft nose wheel steering system according to claim 6, characterized in that, In step 5, a test design evaluation of the aircraft nose wheel steering system is carried out, and the BIT fault detection rate and fault isolation rate of the aircraft nose wheel steering system are evaluated in turn to obtain the evaluation results.

8. The test and diagnosis method for the aircraft nose wheel steering system according to claim 7, characterized in that, In step 6, a test hardware platform is built according to the test and diagnosis plan for the aircraft nose wheel turning system. The aircraft nose wheel turning system adopts a test hardware platform with an independent daughter card. The test signals collected by the independent daughter card are physically separated from the signals involved in the control. The signals are input into an independent AD sampling module and transmitted to the DSP for processing. If the independent daughter card fails, it will not affect the normal completion of the task by the system control part, thus ensuring the reliability of the aircraft nose wheel turning system task.

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