An aircraft pre-flight self-test method

Abstract

This application specifically relates to a pre-flight self-test method for an aircraft, including: dividing LRU devices into Class A devices, Class B devices, and Class C devices. Among them, for Class A devices, the detection directly reads the self-test results of other completed ones as the PBIT test results; for Class B devices, detection needs to be driven by VMC, configuring zero positions, applying incentives or withdrawing incentives; for Class C devices, which are self-detection devices, VMC sends detection instructions to automatically execute the detection, and VMC delays to read the detection results; parallel detection is performed on all Class C devices, and the detection of Class A devices and Class B devices is executed serially at the same time; the detection of each LRU device is implemented in a function unit; the detection status of each LRU device is modeled; the PBIT main function is scheduled to execute once every 12.5 ms, and the function unit for detecting all LRU devices is scheduled once per cycle in the PBIT main function, determining the detection status of the LRU device, executing the corresponding detection steps, and performing state transitions to complete the PBIT detection.

Description

Technical Field

[0001] This application belongs to the field of aircraft pre-flight self-test methods, and particularly relates to an aircraft pre-flight self-test method. Background Art

[0002] Pre-flight Built-In Test (PBIT) of an aircraft is a series of tests performed on all Line Replaceable Unit (LRU) devices of the aircraft management system on the ground before the aircraft takes off, to ensure the proper functioning of the system and meet the flight conditions.

[0003] The main body for performing the PBIT detection function is the Vehicle Management Computer (VMC). The PBIT detection software runs in the VMC, and the VMC automatically completes the detection of all LRU devices of the aircraft management system by executing the PBIT detection software.

[0004] When the VMC performs PBIT detection, the operating system schedules the PBIT tasks at a cycle of 12.5 ms, as Figure 1 shown.

[0005] PBIT detection has requirements for both the detection content and the detection time, and all items must be detected within the specified time. Generally, there are about 15 types of LRU devices as the detection objects, and some of them are shown in the following table:

[0006] Serial number LRU device Detection time 1 Aircraft management computer 11s 2 Fiber optic gyroscope group 1s 3 Accelerometer group 1s 4 Atmospheric system (ADAP) 10s 5 Inertial navigation device 15s 6 External bus CC 10s 7 Attitude and heading equipment 1s 8 Servo subsystem 29s

[0007] PBIT detection adopts the sequential serial detection method, that is, after the detection of LRU device 1 is completed, the detection of LUR device 2 is then executed, and after the detection of LUR device 2 is completed, the detection of LUR device 3 is executed, and so on, until the detection of all LUR devices is completed, as Figure 2 shown. This technical solution has the following defects:

[0008] 1) There are situations where all the PBIT detection contents cannot be completed within the specified time

[0009] Assume that the detection time used by LRU device n is t n , and the total number of devices to be detected is N. The detection time for completing all the PBIT detection contents is Generally, it will far exceed the specified time for PBIT detection. Taking the detection of the LRU devices in the above table as an example, the total detection time is 78 s, while the specified time for PBIT detection does not exceed 30 s;

[0010] 2) The workload of pre-flight planning for PBIT detection is large and the flexibility is poor

[0011] Due to the PBIT detection process, with a scheduling strategy of 12.5 ms as the cycle, and the PBIT detection task itself does not have periodic repeatability. Therefore, for the PBIT detection task, it is equivalent to that when the time of each cycle arrives, the PBIT detection task is interrupted. After the next cycle starts, it continues to execute from the interrupted position of the previous cycle. To ensure the determinism of the PBIT detection task, it is necessary to make prior plans for the PBIT detection tasks executed in each cycle, allocate the steps of the PBIT detection tasks executed in each cycle, and ensure that the interruption position of the PBIT detection task at the end of each cycle is determined. Generally, the specified time for PBIT detection does not exceed 30 s, with a total of 2400 cycles. Planning the execution content of 2400 cycles involves a huge workload. In addition, if there are changes in the PBIT detection task, such as adding a detection content to a certain LRU device, it is necessary to re-plan the step allocation of the PBIT detection tasks for 2400 cycles, resulting in poor flexibility.

[0012] 3) Low utilization rate of VMC during PBIT detection

[0013] Most LRU devices are self-detecting devices, that is, only need the VMC to send detection instructions, and after the agreed detection time is met, read the detection results fed back by the LRU device. The specific detection work is automatically completed by the LRU device according to the detection instructions, such as Figure 3 As shown, for the detection of this type of LRU device, after the VMC sends the detection instructions, it is basically in an idle state, only needs to calculate the time until the agreed detection time arrives, and then reads the results. During the PBIT detection process, the utilization rate of VMC is low.

[0014] In view of the existence of the above technical defects, this application is proposed.

[0015] It should be noted that the disclosure of the above background technical content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. Without clear evidence indicating that the above content was publicly available on the filing date of this application, the above background technology should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0016] The purpose of this application is to provide a pre-flight self-detection method for an aircraft to overcome or mitigate at least one aspect of the known technical defects.

[0017] The technical solution of this application is:

[0018] A pre-flight self-detection method for an aircraft, including:

[0019] The LRU devices are divided into Class A devices, Class B devices, and Class C devices. Among them, Class A devices detect by directly reading the self-test results of other completed ones as the PBIT test results; Class B devices need to be detected by VMC drive, configuring zero positions, applying incentives or canceling incentives; Class C devices are self-detecting devices. The VMC sends detection instructions and automatically executes the detection, and the VMC delays to read the detection results.

[0020] All Class C devices are detected in parallel, and the detection of Class A devices and Class B devices is executed serially at the same time.

[0021] Configure the detection of each LRU device to be implemented in a function unit.

[0022] Model the detection status of each LRU device.

[0023] The PBIT main function is scheduled to execute once every 12.5 ms. The PBIT main function schedules the function units of all LRU device detections once per cycle, judges the detection status of the LRU devices, executes the corresponding detection steps, migrates between states, and completes the PBIT detection.

[0024] According to at least one embodiment of the present application, in the above pre-flight self-test method of the aircraft, the LRU devices include an aircraft management computer, a fiber optic gyro group, an accelerometer group, an air system, an inertial navigation device, an external bus CC, an attitude and heading reference system (AHRS) device, and a servo subsystem.

[0025] According to at least one embodiment of the present application, in the above pre-flight self-test method of the aircraft, the air system is a Class C device.

[0026] Model the detection status of the air system as:

[0027] Instruction sending state, corresponding to the VMC sending detection instructions.

[0028] Instruction holding state, corresponding to the VMC timing and waiting for the detection results.

[0029] Self-detection state, corresponding to the air system executing the detection.

[0030] Result reading state, the VMC reads the detection results.

[0031] Detection end state, the detection ends. Description of the Drawings

[0032] Figure 1 It is a schematic diagram of the VMC executing the PBIT detection task scheduling.

[0033] Figure 2 It is a schematic diagram of the PBIT sequential serial detection process.

[0034] Figure 3 It is a schematic diagram of the autonomous detection of the LRU device provided by the embodiment of the present application;

[0035] Figure 4 It is a schematic diagram of the parallel detection of all Class C devices and the serial execution of the detection of Class A devices and Class B devices provided by the embodiment of the present application;

[0036] Figure 5 It is a schematic diagram of modeling the detection status of the atmosphere system provided by the embodiment of the present application;

[0037] Figure 6 It is a flowchart of detecting the atmosphere system provided by the embodiment of the present application;

[0038] Figure 7 It is a schematic diagram of the PBIT main function scheduling the LRU device detection function unit every cycle provided by the embodiment of the present application. Detailed implementation manners

[0039] To make the technical solutions and their advantages of the present application clearer, the technical solutions of the present application will be further described clearly and completely below in conjunction with the drawings. It can be understood that the specific embodiments described herein are only part of the embodiments of the present application, which are only used to explain the present application and not to limit the present application. It should be noted that for the convenience of description, only the parts related to the present application are shown in the drawings, and other related parts can refer to the general design. Without conflict, the embodiments in the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0040] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present application should be the ordinary meanings understood by those of ordinary skill in the art to which the present application belongs. The words indicating directions such as "upper", "lower", "left", "right", "center", "vertical", "horizontal", "inner", "outer", etc. used in the description of the present application are only used to indicate the relative directions or position relationships, rather than implying that the device or element must have a specific orientation, be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative position relationship may also change accordingly, so it cannot be understood as a limitation to the present application. The terms "first", "second", "third" and similar terms used in the description of the present application are only for descriptive purposes to distinguish different components, and cannot be understood as indicating or implying relative importance. The terms "a", "one" or "the" and similar words used in the description of the present application should not be understood as an absolute limitation on the quantity, but should be understood as having at least one. The terms "including" or "comprising" and similar words used in the description of the present application are intended to cover the elements or objects appearing before the word and the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0041] In addition, it should be noted that unless otherwise clearly specified and defined, the similar terms such as "installation", "connection", and "linkage" used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can also be the communication inside two components. Those skilled in the art can understand their specific meanings in this application according to specific situations.

[0042] The following further elaborates on this application in conjunction with the attached Figures 1 to 7 drawings.

[0043] A pre-flight self-detection method for an aircraft can be specifically implemented as follows:

[0044] Step 1: Classify LRU devices according to the detection method, and divide the LRU devices into Class A devices, Class B devices, and Class C devices, where:

[0045] For Class A devices, the detection directly reads the self-detection results of other completed ones, such as PUBIT and IFBIT, as the PBIT detection result;

[0046] Class B devices need to be detected with VMC drive, and zero position is configured, excitation is applied or removed;

[0047] Class C devices are self-detection devices. The VMC sends a detection instruction and automatically executes the detection. The VMC delays to read the detection result.

[0048] Step 2: Establish a detection process. All Class C devices are detected in parallel, and the detection of Class A devices and Class B devices is executed serially at the same time, as Figure 4 shown.

[0049] Step 3: Configure the detection of each LRU device to be implemented in a function unit, rather than processing the detection of multiple LRU devices in one function unit at the same time. Replace the process-oriented design with an object-oriented design, with high cohesion and low coupling, which can effectively avoid global planning;

[0050] Step 4: Model the detection status of each LRU device. The atmosphere system is a Class C device, and its detection steps are as follows: the VMC sends a detection instruction (the instruction lasts for 200 ms) → the VMC times and waits for the result (the atmosphere system executes the detection) → the VMC reads the detection result → the detection ends. According to the detection steps, 5 detection statuses of the atmosphere system can be established: instruction sending status, instruction holding status, self-detection status, result reading status, and detection end status, as Figure 5 shown. Furthermore, the implementation process of the atmosphere system detection can be formulated according to the detection status of the atmosphere system, asFigure 6 as shown

[0051] Step Five: The PBIT main function is scheduled to execute once every 12.5 ms. The PBIT main function schedules all function units for LRU device detection once per cycle. As Figure 7 shown, determine the detection status of the LRU device, execute the corresponding detection steps, perform state transitions, complete the PBIT detection, and use the LRU device detection status management to replace the detection process task planning. Based on replacing the process-oriented design with an object-oriented design, the drawbacks of global planning can be effectively avoided, ensuring high cohesion and low coupling in implementation.

[0052] The pre-flight self-detection method for an aircraft disclosed in the above embodiments has the following beneficial technical effects:

[0053] 1) It can greatly save the time for PBIT detection. The detection time of PBIT is reduced from the sum of the detection times of all devices to the detection time of the device with the longest time among all LRU devices;

[0054] 2) The detection status describes the detection steps of the LRU device, and the state transition describes the switching of the detection steps. The detection of different LRU devices is realized by independent units, avoiding cross-interference, with high cohesion and low coupling, which can greatly reduce the complexity of detection implementation;

[0055] 3) It can greatly improve the utilization rate of the VMC. After the VMC sends a detection instruction, while timing, it detects the LRU devices that require VMC drive to complete the detection.

[0056] The various embodiments in the specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0057] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings. Those skilled in the art should understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. An aircraft pre-flight self-test method, characterized in that, Including: The LRU devices are divided into Class A devices, Class B devices, and Class C devices. Among them, Class A devices detect and directly read the self-test results of other completed devices as the PBIT test results; Class B devices need to be detected by VMC drive, configure zero position, apply excitation or cancel excitation; Class C devices are self-detecting devices. VMC sends detection instructions and automatically executes the detection. VMC delays to read the detection results; Parallel detection is performed on all Class C devices, and the detection of Class A devices and Class B devices is executed serially at the same time; Configure the detection of each LRU device to be implemented in a function unit; Model the detection status of each LRU device; The PBIT main function is scheduled to execute once every 12.5 ms. The PBIT main function schedules the function unit for the detection of all LRU devices once per cycle, judges the detection status of the LRU device, executes the corresponding detection steps, migrates between states, and completes the PBIT detection; The LRU device includes an aircraft management computer, a fiber optic gyro group, an accelerometer group, an air system, an inertial navigation device, an external bus CC, an attitude and heading reference system (AHRS) device, and a servo subsystem; Among them, PBIT represents the pre-flight self-test of the aircraft; VMC represents the aircraft management computer.

2. The pre-flight self-test method of the aircraft according to claim 1, wherein The air system is a Class C device; Modeling the detection status of the air system is as follows: Instruction sending state, corresponding to VMC sending detection instructions; Instruction holding state, corresponding to VMC timing and waiting for detection results; Self-detection state, corresponding to the air system executing the detection; Result reading state, VMC reads the detection results; Detection end state, the detection ends.

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