Method for determining oxygen system of civil aircraft

Abstract

The invention relates to the technical field of aircraft oxygen supply, and discloses a civil aircraft oxygen system determination method, which comprises the following steps: S1, in response to a fault signal input by a teacher platform, determining a unit oxygen pressure leakage rate; s2, monitoring the use state of oxygen masks of the unit, and determining the overall oxygen volume utilization rate of the unit based on the use condition of each mask; s3, the overall oxygen pressure utilization rate of the unit is determined according to the overall oxygen volume utilization rate of the unit and preset oxygen cylinder parameters; the defect that a model cannot be adjusted according to real-time fault scenes and unit operation behaviors in the prior art is overcome by dynamically responding to fault level signals input by a teacher platform, matching leakage rate parameters in real time and integrating a monitoring mechanism of the starting state of a multi-source oxygen mask; and a grading fault target pressure threshold value judgment and leakage rate dynamic zero clearing strategy is adopted, so that the accuracy of oxygen leakage rate calculation is ensured, the trueness of emergency simulation is improved, and a high-fidelity system support is provided for flight training.

Description

Technical Field

[0001] This invention relates to the field of aircraft oxygen supply technology, specifically to a method for determining the oxygen system of a civil aircraft. Background Technology

[0002] An oxygen system is a complete set of equipment that supplies breathing oxygen to occupants in a specific manner. It is mainly used in the fields of aircraft and spacecraft. The aircraft oxygen system is crucial to ensuring the safety of pilots and passengers. Especially during the training process of advanced simulators, pilots can become familiar with the use of oxygen masks, the operation procedures of the oxygen system, and the inspection and monitoring of the oxygen system at different stages of flight. This enables them to correctly and quickly handle emergencies related to the oxygen system in actual flights.

[0003] Currently, in the modeling of oxygen systems for civil aircraft, existing technologies mainly rely on simplified static models and preset parameters. When simulating the oxygen system state, they cannot respond in real time to fault signals input from the instructor's console or the actual usage status of the crew's oxygen masks. This leads to serious deviations in determining leakage rate, volume utilization rate, and pressure consumption rate. This simplified method ignores the influence of dynamic factors, and the model cannot adjust leakage rate parameters and calculate the overall volume utilization rate based on real-time input. This may result in insufficient accuracy in updating oxygen cylinder pressure, causing untimely and inaccurate generation of warning signals, and failing to guarantee the authenticity and reliability of oxygen system simulation results.

[0004] Therefore, a method for determining the oxygen system of civil aircraft is proposed to solve the above problems. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a method for determining the oxygen system of civil aircraft, thus solving the problems mentioned in the background section.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a method for determining the oxygen system of a civil aircraft, the method comprising the following steps: S1. In response to the fault signal input from the instructor's console, determine the oxygen pressure leakage rate of the unit; S2. Monitor the usage status of the unit's oxygen masks and determine the overall oxygen volume utilization rate of the unit based on the usage status of each mask. S3. Determine the overall oxygen pressure utilization rate of the unit based on the overall oxygen volume utilization rate of the unit and the preset oxygen cylinder parameters; S4. Combining the oxygen pressure leakage rate and oxygen pressure utilization rate, the overall oxygen pressure consumption rate of the computer group; S5. Update the current oxygen cylinder pressure value of the unit based on the oxygen pressure consumption rate; S6. When the current oxygen cylinder pressure value of the unit is lower than the preset threshold, an oxygen system warning signal is generated.

[0007] Preferably, step S1 includes the following steps: S11. Receive oxygen leak fault instructions from the instructor's console control interface in real time. The instructions include a fault level identifier. S12. Parse the fault level identifier, associate it with the pre-stored fault type database, and determine the target pressure threshold; S13. Read the current oxygen cylinder pressure sensor data of the unit and compare the values ​​with the target pressure threshold. S14. If the current pressure value is greater than the target value, the settable leakage rate parameter is called as the output value, where the leakage rate range is 0-100psi / s; S15. When the current pressure value is less than or equal to the target value and the duration exceeds the preset threshold, the leakage rate will be reset to zero and a no-leakage status log will be generated. When a continuous low-pressure state is detected, the system will generate a leakage warning.

[0008] Preferably, the target pressure threshold in S12 is dynamically determined through the following steps: S121. Search the aircraft parameter database according to the aircraft model code and extract the corresponding critical pressure reference value; S122. Match the fault level identifier with the preset level-pressure mapping table and calculate the dynamic offset. S123. The target pressure threshold is obtained by superimposing the critical pressure reference value and the dynamic offset. It is mainly used to simulate the system response characteristics under different fault levels, rather than for actual fault diagnosis. In practical applications, the system will comprehensively judge the fault level based on historical data and real-time status. S124. Verify whether the target pressure threshold is within the physically feasible range; otherwise, enable the default threshold.

[0009] Preferably, step S2 includes the following steps: S21. Continuously monitor the activation status of oxygen masks on the pilot's side, co-pilot's side, and observer's side using a sensor array; S22. When any oxygen mask is activated, its corresponding volume utilization rate value is retrieved from the parameter configuration library. This value is a settable constant. S23. For unused oxygen masks, the automatic allocation volume utilization rate is zero; S24. Convert the utilization rate of each mask's volume in seconds and sum them to generate the overall volume utilization rate. The specific formula is as follows: ; in Indicates the pilot's side. Indicates the co-pilot's side. This indicates the observer's side, with units in liters per second.

[0010] Preferably, the volume utilization rate parameter in S24 is configured through the following steps: S241. Load the default volume utilization template according to the aircraft model, with a typical value of 6.2 liters / minute; S242. Receive custom parameters input from the instructor's console, override the default values, and store them in the parameter configuration library; S243. Verify whether the custom parameters are within the safe range; otherwise, trigger a parameter anomaly alarm.

[0011] 6. The method for determining the oxygen system of a civil aircraft according to claim 1, characterized in that: step S3 includes the following steps: S31. Obtain the full-load pressure and volume parameters of the oxygen cylinder from the model parameter database; S32. Verify the validity of the floor area ratio data; if invalid, use the most recent valid value. S33. Based on the physical conversion relationship, the volume utilization rate is mapped to the pressure utilization rate. The specific formula is as follows: ; in The oxygen cylinders of the unit are at full load pressure. The volume of the unit's oxygen cylinder. This refers to the overall oxygen pressure utilization rate of the unit.

[0012] Preferably, the oxygen cylinder parameters in S31 are initialized through the following steps: S311. Load the oxygen cylinder parameter set associated with the aircraft registration number when the system starts up; S312. Regularly check the integrity of the parameter set and synchronize it from the cloud backup library when it is missing. The S313 is configured with the following default parameters for narrow-body passenger aircraft: 1850 psi full load pressure and 3256 liters volume.

[0013] Preferably, step S4 includes the following steps: S41. Real-time reading of leakage rate parameters and pressure utilization rate parameters; S42. Check the consistency of parameter timing and perform smoothing filtering on outliers; S43. Add the two together and take the negative value to generate the pressure consumption rate. The specific expression is as follows: ; in This indicates the overall oxygen pressure consumption rate of the unit. This indicates the oxygen pressure leakage rate. This indicates the overall oxygen pressure utilization rate of the unit.

[0014] Preferably, the smoothing filter in S42 is implemented through the following steps: S421. Calculate the moving average of leakage rate and pressure utilization rate; S422. When the instantaneous fluctuation exceeds the threshold, enable Kalman filter correction; S423, Output the filtered parameters to the consumption rate calculation module.

[0015] Preferably, step S5 includes the following steps: S51. Obtain the fixed operating cycle parameters of the oxygen system simulation model; S52. Multiply the pressure consumption rate by the operating cycle to calculate the pressure change in a single cycle; S53. Read the oxygen cylinder pressure cache value stored in the previous cycle; S54. Add the pressure change to the cache value and update the current pressure value; S55, cyclically execute S52-S54, and output in real time to the flight simulator instrument display interface.

[0016] (III) Beneficial Effects Compared with the prior art, the present invention provides a method for determining the oxygen system of a civil aircraft, which has the following beneficial effects: 1. In this invention, when determining the status of the oxygen system of a civil aircraft, the fault level signal input from the instructor's console is dynamically responded to and the leakage rate parameter is matched in real time. At the same time, a monitoring mechanism for the activation status of multi-source oxygen masks is integrated to solve the defect of existing technologies that cannot adjust the model according to real-time fault scenarios and crew operation behavior. The graded fault target pressure threshold determination and leakage rate dynamic zeroing strategy are adopted to eliminate the problem of static models ignoring the actual fault evolution process, ensure the accuracy of oxygen leakage rate calculation, improve the realism of emergency situation simulation, and provide high-fidelity system support for flight training.

[0017] 2. In this invention, when calculating the oxygen pressure consumption of the unit, a physical conversion model between volume utilization rate and pressure utilization rate is established. Combined with a multi-dimensional parameter anomaly handling mechanism, the calculation deviation caused by data fluctuation and parameter over-limit in traditional methods is overcome. When data anomalies are detected, the correction program is automatically activated to avoid inaccurate calculation of pressure consumption rate and ensure the reliability of oxygen cylinder pressure updates.

[0018] 3. In this invention, during the oxygen system status update process, pressure consumption calculation, cyclic cumulative update, and dynamic early warning threshold adaptation are performed in stages to solve the problems of lagging early warning mechanisms and lack of pressure zone response in existing technologies. Based on the real-time generation technology of early warning thresholds with safety factor, the entire process of closed-loop control from single mask status monitoring to overall system pressure consumption is realized, thereby improving the early warning sensitivity under low pressure conditions. Attached Figure Description

[0019] Figure 1 This is a flowchart of the method for determining the oxygen system of a civil aircraft according to the present invention. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Specific embodiment: A method for determining the oxygen system of a civil aircraft, the method comprising the following steps: S1. In response to the fault signal input from the instructor's console, determine the oxygen pressure leakage rate of the unit; S2. Monitor the usage status of the unit's oxygen masks and determine the overall oxygen volume utilization rate of the unit based on the usage status of each mask. S3. Determine the overall oxygen pressure utilization rate of the unit based on the overall oxygen volume utilization rate and the preset oxygen cylinder parameters. S4. Combine oxygen pressure leakage rate and oxygen pressure utilization rate to calculate the overall oxygen pressure consumption rate of the computer group. S5. Update the current oxygen cylinder pressure value of the unit based on the oxygen pressure consumption rate; S6. When the current oxygen cylinder pressure value of the unit is lower than the preset threshold, an oxygen system warning signal is generated.

[0022] S1 includes the following steps: S11. Receive oxygen leak fault instructions from the instructor's console control interface in real time. The instructions include a fault level identifier. S12. Parse the fault level identifier, associate it with the pre-stored fault type database, and determine the target pressure threshold; The fault level identification is specifically defined into three types: Level 1: minor leakage, Level 2: moderate leakage, and Level 3: severe leakage; The level-pressure mapping table is pre-stored in the fault type database as a lookup table, as shown in the following example: Fault level 1 corresponding dynamic offset =20psi; Fault level 2 corresponding dynamic offset =40psi; Fault level 3 corresponds to dynamic offset =60psi.

[0023] S13. Read the current oxygen cylinder pressure sensor data of the unit and compare the values ​​with the target pressure threshold. S14. If the current pressure value is greater than the target value, the settable leakage rate parameter is called as the output value, where the leakage rate range is 0-100psi / s; S15. When the current pressure value is less than or equal to the target value and the duration exceeds the preset threshold, the leakage rate will be reset to zero and a no-leakage status log will be generated. When a continuous low-pressure state is detected, the system will generate a leakage warning.

[0024] The target pressure threshold in S12 is dynamically determined through the following steps: S121. Search the aircraft parameter database according to the aircraft model code and extract the corresponding critical pressure reference value; S122. Match the fault level identifier with the preset level-pressure mapping table and calculate the dynamic offset: The formula for calculating dynamic offset is: ; in, Indicates dynamic offset. It is a proportionality factor and is set to 20 psi. It is the fault level value and takes the values ​​1, 2, and 3; the formula simplifies the calculation based on a linear relationship, ensuring that the offset increases with the fault level; S123. The target pressure threshold is obtained by superimposing the critical pressure reference value and the dynamic offset. It is mainly used to simulate the system response characteristics under different fault levels, rather than for actual fault diagnosis. In practical applications, the system will comprehensively judge the fault level based on historical data and real-time status. ; in The target pressure threshold, This is the critical pressure reference value. This is the dynamic offset corresponding to the fault level; S124. Verify whether the target pressure threshold is within the physically feasible range of 0.1× Up to 2× Otherwise, the default threshold of 0.5× will be used. ,in This is the critical pressure reference value.

[0025] S2 includes the following steps: S21. Continuously monitor the activation status of oxygen masks on the pilot's side, co-pilot's side, and observer's side using a sensor array; S22. When any oxygen mask is activated, its corresponding volume utilization rate value is retrieved from the parameter configuration library. This value is a settable constant. S23. For unused oxygen masks, the automatic allocation volume utilization rate is zero; S24. Convert the utilization rate of each mask's volume in seconds and sum them to generate the overall volume utilization rate. The specific formula is as follows: ; in Indicates the pilot's side. Indicates the co-pilot's side. This indicates the observer's side, with units in liters per second.

[0026] The floor area ratio parameter in S24 is configured through the following steps: S241. Load the default volume utilization template according to the aircraft model, with a typical value of 6.2 liters / minute; S242. Receive custom parameters input from the instructor's console, override the default values, and store them in the parameter configuration library; S243. Verify whether the custom parameters are within the safe range; otherwise, trigger a parameter anomaly alarm. ; in: This is an alarm indicator; 1 indicates an alarm has been triggered, and 0 indicates a normal alarm. For oxygen mask volume utilization rate; The minimum safe level is 4.0 liters per minute by default. The maximum safe value is 8.0 liters / minute by default.

[0027] S3 includes the following steps: S31. Obtain the full-load pressure and volume parameters of the oxygen cylinder from the model parameter database; S32. Verify the validity of the floor area ratio data; if invalid, use the most recent valid value. S33. Based on the physical conversion relationship, the volume utilization rate is mapped to the pressure utilization rate. The specific formula is as follows: ; in The oxygen cylinders of the unit are at full load pressure. The volume of the unit's oxygen cylinder. This refers to the overall oxygen pressure utilization rate of the unit.

[0028] The oxygen cylinder parameters in S31 are initialized through the following steps: S311. Load the oxygen cylinder parameter set associated with the aircraft registration number when the system starts up; S312. Regularly check the integrity of the parameter set and synchronize it from the cloud backup library when it is missing. The S313 is configured with the following default parameters for narrow-body passenger aircraft: 1850 psi full load pressure and 3256 liters volume.

[0029] S4 includes the following steps: S41. Real-time reading of leakage rate parameters and pressure utilization rate parameters; S42. Check the consistency of parameter timing and perform smoothing filtering on outliers; S43. Add the two together and take the negative value to generate the pressure consumption rate. The specific expression is as follows: ; in This indicates the overall oxygen pressure consumption rate of the unit. This indicates the oxygen pressure leakage rate. This indicates the overall oxygen pressure utilization rate of the unit.

[0030] Smoothing filtering in S42 is achieved through the following steps: S421. Calculate the moving average of leakage rate and pressure utilization rate: ; in Leakage rate after filtering For the i-th historical sample value, This is the sliding window size, and the default value is 5. The number is the sequence number within the window from 1 to N. Although the leakage rate itself is a set value, in actual applications, external interference may cause fluctuations in the measured value. Therefore, the moving average calculation can filter out noise and improve the accuracy of leakage rate judgment. S422. When instantaneous fluctuations exceed the threshold: If the deviation between the measured value and its moving average exceeds 20%, enable Kalman filter correction; S423, Output the filtered parameters to the consumption rate calculation module.

[0031] S5 includes the following steps: S51. Obtain the fixed operating cycle parameters of the oxygen system simulation model; S52. Multiply the pressure consumption rate by the operating cycle to calculate the pressure change in a single cycle; S53. Read the oxygen cylinder pressure cache value stored in the previous cycle; S54. Add the pressure change to the cache value and update the current pressure value; S55. Dynamically generate early warning thresholds based on the current pressure value: ; in As the warning threshold, For safety reasons, This is the initial full-load pressure of the oxygen cylinder. S56. Dynamically generate multi-level early warning thresholds based on the current pressure value and activate graded responses: = ; = ; = ; in, , , These represent the warning thresholds for levels one, two, and three, respectively. This is the initial full-load pressure of the oxygen cylinder. , , This is the safety factor, the default value. =0.8、 =0.5、 =0.3; Hierarchical Response Protocol: When the current pressure value meets <Current pressure value≤ When this happens, a primary visual cue is activated, such as a flashing dashboard indicator; The current pressure value meets <Current pressure value≤ When activated, a secondary voice alarm is generated, and a voice prompt is generated. When the current pressure value is ≤ When activated, the Level 3 emergency response simulation program is activated, automatically triggering the emergency checklist.

[0032] The warning signal is output to the flight simulator instrument display interface in real time.

[0033] S6. When the current oxygen cylinder pressure value of the unit is lower than different preset thresholds, a graded oxygen system warning signal is generated, specifically including: S61. When the pressure value is between the first-level threshold and the second-level threshold, a visual cue signal is generated; S62. When the pressure value is between the secondary threshold and the tertiary threshold, a voice alarm signal is generated; S63. When the pressure value is lower than the level 3 threshold, an emergency response simulation signal is generated.

[0034] The steps of this method are as follows: Step 1: Fault Command Response and Leakage Assessment System In the flight simulator environment, fault commands input at the instructor's console trigger the cascading response mechanism of the oxygen system status engine. The system parses fault level identifiers and performs pattern matching against a pre-set fault feature database to generate a set of fault parameters with dynamic weights. Real-time data from oxygen cylinder pressure sensors is streamed through a timing alignment processor and compared with a dynamically calculated target pressure threshold at millisecond levels. When a pressure value exceeds the fault threshold, an adaptive leakage rate calculation channel is activated; when the pressure value falls below the safety threshold, a leakage rate zeroing protocol is automatically executed, and a status log is generated. The entire process employs anti-interference verification technology to ensure accuracy even in strong electromagnetic environments and with data loss.

[0035] Step 2: Multi-source mask status monitoring and volume conversion mechanism Three sets of high-sensitivity infrared optical sensors configured in the cockpit form a mask status monitoring array, capturing the physical displacement characteristics of the mask through non-contact detection technology. The raw data collected by the sensors is binarized and converted into enable / disable status codes, establishing a real-time mapping relationship between mask position and volume consumption. The system's built-in volume template matching engine calls upon standard consumption features from the aircraft's parameter library to intelligently correct abnormal displacement signals. A dual-channel circuit breaker mechanism automatically switches to the backup parameter channel when a single point of continuous data anomaly is detected, while simultaneously activating a historical data interpolation compensation algorithm to ensure the continuity of the volume conversion process. This mechanism solves the monitoring blind spot problem in complex environments such as view obstruction and reflection interference.

[0036] Step 3: Pressure Conversion and Consumption Calculation Engine A physical conversion model based on aerospace fluid dynamics principles transforms discrete volumetric consumption data streams into continuous pressure parameters. The system dynamically loads core parameters of the oxygen cylinder's full-load pressure and volume from a cloud-based parameter library, establishing a physical conversion pipeline between pressure and volume. An abnormal data trigger mechanism automatically activates the most recent valid value replacement strategy when parameters exceed limits, simultaneously triggering a parameter safety range verification alarm. The consumption calculation layer employs temporal consistency verification technology, performing sliding window mean filtering on the input parameters to eliminate transient fluctuations. When a drastic data jump is detected, the system intelligently switches to Kalman filtering mode to reconstruct the data curve, ensuring the stability of the pressure consumption rate calculation.

[0037] Step 4: Pressure Status Update and Dynamic Early Warning System The oxygen cylinder pressure status update engine employs a fixed-cycle refresh strategy, performing iterative calculations based on the cumulative effect of pressure consumption rate and time variables. The system utilizes shared memory pool technology to achieve millisecond-level data synchronization, completing three steps within a single update cycle: calculating pressure changes, reading cached values, and refreshing real-time values. A floating threshold generator dynamically adjusts the warning threshold based on the aircraft's safety factor, establishing a three-level warning response protocol: visual cues are activated when the pressure value exceeds the first-level threshold; an audio alarm is triggered when the second-level threshold is reached; and an emergency response simulation procedure is initiated when the third-level threshold is reached. Warning signals are transmitted through the multimodal output interface of the cockpit display unit, generating alarm feedback that conforms to real-world flight scenarios.

[0038] Step 5: Closed-loop control and system self-healing mechanism The entire oxygen system state simulation process constructs a seven-layer autonomous control node architecture: fault decoder → leak detector → state acquisition unit → volume converter → pressure calculator → threshold generator → early warning actuator. Each node achieves bidirectional communication via a high-speed data bus, forming a self-correcting technical closed loop. The system's built-in node health monitoring system evaluates the output quality of each layer in real time, automatically activating the data compensation algorithm of adjacent nodes when a single point of failure is detected. A unique triple redundancy protection mechanism seamlessly switches to backup computing channels in the event of core node failure, ensuring continuous system operation under both hardware and software anomalies.

[0039] Step Six: Real-time Interaction and Training Performance Optimization The oxygen state simulation system is deeply integrated with flight training courses, dynamically adjusting the simulation difficulty coefficient through a scenario response engine. In emergency response training mode, the system automatically enhances leak detection sensitivity and reduces warning response time, constructing a high-pressure training environment. Training effectiveness assessment records pilot operational response data for each pressure range, generating multi-dimensional response capability analysis reports. The instructor's console's visual monitoring interface displays a real-time oxygen system status topology diagram, supports historical data playback and reproduction of typical fault scenarios, providing data support for training effectiveness evaluation.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for determining the oxygen system of a civil aircraft, characterized in that: The method includes the following steps: S1. In response to the fault signal input from the instructor's console, determine the oxygen pressure leakage rate of the unit; S2. Monitor the usage status of the unit's oxygen masks and determine the overall oxygen volume utilization rate of the unit based on the usage status of each mask. S3. Determine the overall oxygen pressure utilization rate of the unit based on the overall oxygen volume utilization rate of the unit and the preset oxygen cylinder parameters; S4. Combining the oxygen pressure leakage rate and oxygen pressure utilization rate, the overall oxygen pressure consumption rate of the computer group; S5. Update the current oxygen cylinder pressure value of the unit based on the oxygen pressure consumption rate; S6. When the current oxygen cylinder pressure value of the unit is lower than the preset threshold, an oxygen system warning signal is generated.

2. The method for determining the oxygen system of a civil aircraft according to claim 1, characterized in that: S1 includes the following steps: S11. Receive oxygen leak fault instructions from the instructor's console control interface in real time. The instructions include a fault level identifier. S12. Parse the fault level identifier, associate it with the pre-stored fault type database, and determine the target pressure threshold; S13. Read the current oxygen cylinder pressure sensor data of the unit and compare it with the target pressure threshold. S14. If the current pressure value is greater than the target value, the settable leakage rate parameter is called as the output value, where the leakage rate range is 0-100psi / s; S15. When the current pressure value is less than or equal to the target value and the duration exceeds the preset threshold, the leakage rate will be reset to zero and a no-leakage status log will be generated. When a continuous low-pressure state is detected, the system will generate a leakage warning.

3. The method for determining the oxygen system of a civil aircraft according to claim 2, characterized in that: The target pressure threshold in S12 is dynamically determined through the following steps: S121. Search the aircraft parameter database according to the aircraft model code and extract the corresponding critical pressure reference value; S122. Match the fault level identifier with the preset level-pressure mapping table and calculate the dynamic offset. S123. The target pressure threshold is obtained by superimposing the critical pressure reference value and the dynamic offset. It is mainly used to simulate the system response characteristics under different fault levels, rather than for actual fault diagnosis. In practical applications, the system will comprehensively judge the fault level based on historical data and real-time status. S124. Verify whether the target pressure threshold is within the physically feasible range; otherwise, enable the default threshold.

4. The method for determining the oxygen system of a civil aircraft according to claim 1, characterized in that: S2 includes the following steps: S21. Continuously monitor the activation status of oxygen masks on the pilot's side, co-pilot's side, and observer's side using a sensor array; S22. When any oxygen mask is activated, its corresponding volume utilization rate value is retrieved from the parameter configuration library. This value is a settable constant. S23. For unused oxygen masks, the automatic allocation volume utilization rate is zero; S24. Convert the utilization rate of each mask's volume in seconds and sum them to generate the overall volume utilization rate. The specific formula is as follows: ； in Indicates the pilot's side. Indicates the co-pilot's side. This indicates the observer's side, with units in liters per second.

5. The method for determining the oxygen system of a civil aircraft according to claim 4, characterized in that: The volume utilization rate parameter in S24 is configured through the following steps: S241. Load the default volume utilization template according to the aircraft model, with a typical value of 6.2 liters / minute; S242. Receive custom parameters input from the instructor's console, override the default values, and store them in the parameter configuration library; S243. Verify whether the custom parameters are within the safe range; otherwise, trigger a parameter anomaly alarm.

6. The method for determining the oxygen system of a civil aircraft according to claim 1, characterized in that: S3 includes the following steps: S31. Obtain the full-load pressure and volume parameters of the oxygen cylinder from the model parameter database; S32. Verify the validity of the floor area ratio data; if invalid, use the most recent valid value. S33. Based on the physical conversion relationship, the volume utilization rate is mapped to the pressure utilization rate. The specific formula is as follows: ； in The oxygen cylinders of the unit are at full load pressure. This refers to the volume of the unit's oxygen cylinders. This refers to the overall oxygen pressure utilization rate of the unit.

7. The method for determining the oxygen system of a civil aircraft according to claim 6, characterized in that: The oxygen cylinder parameters in S31 are initialized through the following steps: S311. Load the oxygen cylinder parameter set associated with the aircraft registration number when the system starts up; S312. Regularly check the integrity of the parameter set and synchronize it from the cloud backup library when it is missing. The S313 is configured with the following default parameters for narrow-body passenger aircraft: 1850 psi full load pressure and 3256 liters volume.

8. The method for determining the oxygen system of a civil aircraft according to claim 1, characterized in that: S4 includes the following steps: S41. Real-time reading of leakage rate parameters and pressure utilization rate parameters; S42. Check the consistency of parameter timing and perform smoothing filtering on outliers; S43. Add the two together and take the negative value to generate the pressure consumption rate. The specific expression is as follows: ； in This indicates the overall oxygen pressure consumption rate of the unit. This indicates the oxygen pressure leakage rate. This indicates the overall oxygen pressure utilization rate of the unit.

9. The method for determining the oxygen system of a civil aircraft according to claim 8, characterized in that: The smoothing filter in S42 is achieved through the following steps: S421. Calculate the moving average of leakage rate and pressure utilization rate; S422. When the instantaneous fluctuation exceeds the threshold, enable Kalman filter correction; S423, Output the filtered parameters to the consumption rate calculation module.

10. The method for determining the oxygen system of a civil aircraft according to claim 1, characterized in that: S5 includes the following steps: S51. Obtain the fixed operating cycle parameters of the oxygen system simulation model; S52. Multiply the pressure consumption rate by the operating cycle to calculate the pressure change in a single cycle; S53. Read the oxygen cylinder pressure cache value stored in the previous cycle; S54. Add the pressure change to the cache value and update the current pressure value; S55, cyclically execute S52-S54, and output in real time to the flight simulator instrument display interface.

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