A pressure signal filtering method for surge determination

Abstract

The application provides a pressure signal filtering method for surge judgment, which comprises the following steps: collecting a pressure signal P after an engine high-pressure compressor; constructing a limiting filter module, so that the pressure signal P passes through the limiting filter module to obtain a pressure signal P_LF; constructing a pulse filter module, so that the pressure signal P_LF passes through the pulse filter module to obtain a pressure signal P_IF; and constructing an inertia filter module, so that the pressure signal P_IF passes through the inertia filter module to obtain a pressure signal P_F. The method provided by the application can effectively identify abnormal signals in real time, suppress single-cycle and double-cycle interference, and is suitable for pressure signal filtering for surge judgment.

Description

Technical Field

[0001] This application belongs to the field of aero-engine control technology, and specifically relates to a pressure signal filtering method for surge detection. Background Technology

[0002] Surge is a serious instability condition in aero-engines. It can affect engine performance in mild cases and damage the engine in severe cases, jeopardizing flight safety. Therefore, accurately identifying surge before it occurs or in its early stages, and then taking appropriate anti-surge measures, is essential for stable engine control.

[0003] Currently, most methods for judging surge in aero-engines analyze the pressure signal at the high-pressure compressor outlet. During surge, the pressure signal exhibits low-frequency, high-amplitude oscillations. However, the engine operates under complex environments including noise, high temperature, vibration, and electromagnetic radiation. The pressure signal is inevitably interfered with by noise during acquisition and transmission, contaminating the output data and causing it to deviate from the actual signal. Therefore, to accurately identify the abnormal pressure data used as the basis for surge judgment, necessary filtering processing must be performed to remove noise signals and restore the actual signal.

[0004] Filtering methods are broadly classified into analog filtering and digital filtering. Analog filtering uses analog filter circuits to allow only signals within a specific frequency range to pass through while blocking noise signals. Analog filter circuits require a clear understanding of both the normal frequency range of the signal and the noise frequency range. Digital filtering, on the other hand, employs filtering algorithms to process signals at the data acquisition terminal computer. Digital filtering is flexible and versatile, capable of achieving similar functions to analog filtering as well as fulfilling special filtering requirements that are difficult to achieve with analog filter circuits. Therefore, digital filtering is commonly used in modern engines.

[0005] Currently used digital filtering methods include amplitude limiting filtering, median filtering, arithmetic mean filtering, weighted recursive mean filtering, and inertial filtering. Amplitude limiting and median filtering are mainly used to deal with occasional large pulse interference; arithmetic mean filtering, weighted recursive mean filtering, and inertial filtering are mainly used to suppress small-amplitude high-frequency pulse interference. However, in the processing of airborne pressure signals for aero-engines, due to limitations in computational load and capability, amplitude limiting and inertial filtering are frequently used. However, amplitude limiting and inertial filtering are difficult to filter out randomly occurring pulse interference in real time, leading to potential misjudgments in surge detection logic. Summary of the Invention

[0006] The purpose of this application is to provide a pressure signal filtering method for surge detection, so as to solve or mitigate at least one of the above-mentioned problems.

[0007] This application provides a pressure signal filtering method for surge detection, the method comprising:

[0008] acquiring a pressure signal P after a high-pressure compressor of an engine;

[0009] a limiting filter module is constructed, and the pressure signal P is filtered by the limiting filter module to obtain a pressure signal P_LF;

[0010] a pulse filter module is constructed, and the pressure signal P_LF is filtered by the pulse filter module to obtain a pressure signal P_IF;

[0011] an inertia filter module is constructed, and the pressure signal P_IF is filtered by the inertia filter module to obtain a pressure signal P_F.

[0012] Further, the limiting filter module takes the acquired pressure value P (k) as input, calculates a steady-state value P_F2 (k) of the current period of the pressure signal through first inertia filtering, first limiting filtering and second inertia filtering, and filters out occasional large-amplitude interference quantities that greatly exceed the steady-state value through second limiting filtering.

[0013] Further, the filtering process of the filtered pressure value P_F1 (k) obtained through the first inertia filtering is as follows:

[0014] P_F1 (k) = (1-a) * P (k) +a*P_F1 (k-1)

[0015] In the formula, a is a coefficient; the subscript k represents the current period, and the subscript k-1 represents the previous period.

[0016] Further, the filtering process of the first limiting filtering is as follows:

[0017] When , a reconstructed pressure value P_RF (k) is obtained through data reconstruction, and the reconstruction method is as follows:

[0018] If P (k) -P_F1 (k) ≥ 0, P_RF (k) = (1+A) * P_F1 (k) ;

[0019] If P (k) -P_F1 (k) < 0, P_RF (k) = (1-A) * P_F1 (k) ;

[0020] When , P_RF (k) = P (k)

[0021] wherein A is a threshold value.

[0022] Further, the filtered pressure value P_F2 (k) is obtained by the second inertial filtering, and the filtering process is as follows:

[0023] P_F2 (k) = (1-b) * P_RF (k) +b*P_F2 (k-1)

[0024] wherein b is a coefficient.

[0025] Further, the filtering process of the second limiting filtering is as follows:

[0026] The filtered pressure value P_F2 (k) obtained by the second inertial filtering and the collected value P (k) are taken as inputs, and the limiting filtering module processes the pressure value P_LF (k) , and the process is as follows:

[0027] When , P_LF (k) =P_F2 (k-1) ; otherwise, P_LF (k) =P (k) ;

[0028] wherein B is a threshold value.

[0029] Further, the pulse filtering module takes the pressure value P_LF (k) processed by the limiting filtering module as input, and obtains the steady value P_F2 (k) ' of the current period by the third inertial filtering, the third limiting filtering and the fourth inertial filtering; if the pressure value P_LF (k) exceeds a certain range of the steady value P_F2 (k) ' of the current period, an interference or an abnormal state of the engine entering into surge occurs, and the output value of the pulse filtering is determined according to the data of subsequent periods to further judge and filter out single-period or double-period interference.

[0030] Further, the pressure signal value processed by the third inertial filtering is as follows:

[0031] P_F1' (k) = (1-a) * P_LF (k) +a*P_F1' (k-1) ;

[0032] The filtering process of the third limiting filtering is as follows:

[0033] When At this time, the reconstructed pressure value P_RF' is obtained through data reconstruction (k) The reconstruction method is as follows:

[0034] If P_LF (k) -P_F1' (k) ≥ 0, P_RF' (k) = (1 + A) * P_F1' (k) ;

[0035] If P (k) -P_F1 (k) < 0, P_RF' (k) = (1 - A) * P_F1' (k) ;

[0036] When P_RF' (k) = P_LF (k) ;

[0037] The fourth inertial filtering processed pressure signal value is:

[0038] P_F2' (k) = (1 - b) * P_RF' (k) + b * P_F2' (k-1) .

[0039] Further, the filtering process of the pulse filtering is:

[0040] Let P_state (k) be the relative pressure change amount; according to the values of k-1 and k, it is determined whether the pressure signal dynamic identifiers State_α and State_β are valid, State_α is an entering pulse logic 1 judgment factor, and State_β is an entering pulse logic 2 judgment factor;

[0041] The State_α voting logic is shown in Table 1, and the State_β voting logic is shown in Table 2, wherein "1" represents validity, "0" represents invalidity, P_α and P_β are dynamic discrimination thresholds, and K1*P_α and K2*P_β are data anomaly thresholds;

[0042] Table 1 State_α state judgment logic

[0043] No. P_state (k-1) ]]> P_state (k) ]]> State_α (k) ]]> 1 P_state (k-1) ≤P_α]]> P_state (k) >P_alpha 1 2 P_state (k-1) ≤P_α]]> P_state (k) ≤P_α]]> 0 3 P_state (k-1) >P_alpha -P_state (k) >P_α 1 4 P_state (k-1) >P_alpha P_state (k) ≤P_α]]> 1

[0044] Table 2 State_β state judgment logic

[0045]

[0046]

[0047] wherein, when K1*P_α≤P_state (k) <K2*P_β, and State_α (k-1) =0, the logic in Table 3 is executed;

[0048] Table 3 Pulse Filter Logic 1

[0049]

[0050] wherein, when P_state (k) ≥K2*P_β, and State_β (k-1) =0, the logic in Table 4 is executed;

[0051] Table 4 Pulse Filter Logic 2

[0052]

[0053]

[0054] When neither of the above two filter logics is entered:

[0055] Pulse-filtered pressure signal value: P_IF (k) =P_LF (k)

[0056] Further, the inertial filter module filters out high-frequency components in the signal, and makes the signal moderately smooth, in the following process:

[0057] Filtered pressure signal value: P_F (k) =(1-c)*P_IF (k) +c*P_F (k-1)

[0058] In the formula, c is a coefficient. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to more clearly illustrate the technical solutions provided in the present application, the following will briefly introduce the drawings. Obviously, the drawings described below are only some embodiments of the present application.

[0060] Figure 1 The figure is a schematic diagram of the overall process of the pressure signal filtering method in the present community.

[0061] Figure 2 The figure is a schematic diagram of the limiting filter module in the present application.

[0062] Figure 3 The figure is a schematic diagram of the pulse filter module in the present application. DETAILED DESCRIPTION

[0063] ​For the purpose, technical solutions and advantages of the present application, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application.

[0064] In order to overcome the shortcomings in the prior art, the present application proposes a pressure signal filtering method suitable for surge judgment. The method can effectively filter out random pulse interference in the form of combined filtering, and provide reliable basic signals for surge judgment logic in real time.

[0065] As shown in Figure 1 , the pressure signal filtering method proposed in the present application mainly constructs an amplitude limiting filter module, a pulse filter module and an inertia filter module, and the three modules are connected in series, so that the pressure signal after the high-pressure compressor of the engine passes through the above three modules in turn to obtain the available pressure signal.

[0066] The specific process of the above three modules constructed in the present application is as follows:

[0067] I. Amplitude limiting filter module

[0068] The amplitude limiting filter module is used to filter out occasional large amplitude pulse interference that exceeds the physical limit (i.e. it is impossible to appear even when surging).

[0069] As shown in Figure 2 , the amplitude limiting filter module takes the collected pressure value P (k) as input, calculates the steady-state value P_F2 (k) of the current period of the pressure signal through inertia filter 11, amplitude limiting filter 13 and inertia filter 12, and filters out occasional large amplitude interference that exceeds the steady-state value through amplitude limiting filter 14. Details are as follows:

[0070] 1.1) Inertia filter 11

[0071] Through the inertia filter 11, the filtered pressure value P_F1 (k) is obtained, and the filtering calculation is as follows:

[0072] P_F1 (k) =(1-a)*P (k) +a*P_F1 (k-1)

[0073] In the formula, a is a coefficient, which is determined according to the specific circumstances of the project; k represents the current period, k-1 represents the previous period, and k+1 represents the next period, and so on.

[0074] 1.2) Amplitude limiting filter 13

[0075] When , the reconstructed pressure value P_RF (k) is obtained through data reconstruction, and the reconstruction method is as follows:

[0076] If P (k) - P_F1 (k) ≥ 0, P_RF (k) = (1 + A) * P_F1 (k) ;

[0077] If P (k) - P_F1 (k) < 0, P_RF (k) = (1 - A) * P_F1 (k) .

[0078] When , P_RF (k) = P (k)

[0079] Wherein, A is a threshold value, determined according to the specific circumstances of the project.

[0080] 1.3) Inertial filtering 12

[0081] Through the inertial filtering 2, the filtered pressure value P_F2 (k) is obtained, calculated as follows:

[0082] P_F2 (k) = (1 - b) * P_RF (k) + b * P_F2 (k-1)

[0083] Wherein, b is a coefficient, selected according to the specific circumstances of the project.

[0084] 1.4) Limiting filtering 14

[0085] P_F2 (k) calculated by steps 2.1-2.3 and the acquisition value P (k) are taken as inputs, and the limiting filtering module processed pressure value P_LF (k) is output, calculated as follows:

[0086] When , P_LF (k) = P_F2 (k-1) ; otherwise P_LF (k) = P (k) .

[0087] Wherein, B is a threshold value, determined according to the specific circumstances of the project.

[0088] II. Pulse filtering module

[0089] Pulse filter logic is used to filter out the occasional pulse interference in the signal. When the signal value mutation is small, it may be interference or the real characteristics of the signal, so further judgment is needed on the basis of amplitude limiting filter.

[0090] As shown in Figure 3 , the pulse filter module takes P_LF (k) as input, and calculates the steady state value P_F2 (k) ' of the current period through inertial filter 1, amplitude limiting filter 1 and inertial filter 2. The process is the same as the process of 1.1) ~ 1.3) in the amplitude limiting filter module. If P_LF (k) exceeds a certain range of the steady state value P_F2 (k) ' of the current period, either interference occurs or the engine enters abnormal state such as surge, and then further judgment is made according to the data of the next 2-3 periods to determine the output value of pulse filter and filter out single period or double period interference. Details are as follows:

[0091] 2.1) Inertial filter 21

[0092] The processed pressure signal value of inertial filter 21: P_F1' (k) = (1-a) * P_LF (k) + a * P_F1' (k-1) .

[0093] 2.2) Amplitude limiting filter 23

[0094] When , the reconstructed pressure value P_RF' (k) is obtained through data reconstruction, and the reconstruction method is as follows:

[0095] If P_LF (k) -P_F1' (k) ≥ 0, P_RF' (k) = (1+A) * P_F1' (k) ;

[0096] If P (k) -P_F1 (k) < 0, P_RF' (k) = (1-A) * P_F1' (k) .

[0097] When , P_RF' (k) = P_LF (k) .

[0098] 2.3) Inertial filter 22

[0099] The processed pressure signal value of inertial filter 22: P_F2' (k) = (1-b) * P_RF'(k) + b * P_F2 (k-1) .

[0100] 2.4) Pulse filter 24

[0101] The following related variables are defined:

[0102] State_α and State_β are dynamic identification of pressure signal;

[0103] P_α and P_β are dynamic discrimination threshold;

[0104] K1*P_α and K2*P_β are data anomaly threshold.

[0105] The values of the above variables are determined according to the specific circumstances of the project. Among them, State_α, P_α and K1*P_α are used together, and State_β, P_β and K2*P_β are used together.

[0106] Let P_state (k) be the relative change of pressure. According to the values of k-1 and k, it is judged whether State_α and State_β are valid. State_α is a judgment factor for entering pulse logic 1, and State_β is a judgment factor for entering pulse logic 2.

[0107] The State_α voting logic is shown in Table 1, and the State_β voting logic is shown in Table 2. In the table, "1" means valid, and "0" means invalid.

[0108] Table 1 State_α state judgment logic

[0109] No. P_state (k-1) ]]> P_state (k) ]]> State_α (k) ]]> 1 P_state (k-1) ≤P_α]]> P_state (k) >P_alpha 1 2 P_state (k-1) ≤P_α]]> P_state (k) ≤P_α]]> 0 3 P_state (k-1) >P_alpha -P_state (k) >P_α 1 4 P_state (k-1) P_state P_state (k) ≤P_α]]> 1

[0110] Table 2 State_β state judgment logic

[0111] No. P_state (k-1) ]]> P_state (k) ]]> State_β (k) ]]> 1 P_state (k-1) ≤P_β]]> P_state (k) P_state 1 2 P_state (k-1) ≤P_β]]> P_state (k) ≤P_β]]> 0 3 P_state (k-1) P_state -P_state (k) >P_β 1 4 P_state (k-1) >P_beta P_state (k) ≤P_β]]> 1

[0112] 2.4.1) Pulse filter logic 1

[0113] When K1*P_α≤P_state (k) <K2*P_β, and State_α (k-1) =0, execute the logic in Table 3.

[0114] Table 3 Pulse filter logic 1

[0115]

[0116]

[0117] 2.4.2) Pulse filter logic 2

[0118] When P_state (k) ≥ K2*P_beta, and State_beta (k-1) = 0, execute the logic in Table 4.

[0119] Table 4 Pulse filter logic 2

[0120]

[0121]

[0122] 2.4.3) When neither of the above two filter logics is entered:

[0123] The pressure signal value after pulse filter processing: P_IF (k) = P_LF (k) .

[0124] III. Inertial filter module

[0125] The inertial filter module is used to filter out high-frequency components in the signal and to smooth the signal moderately, in the following manner:

[0126] The pressure signal value after filtering: P_F (k) = (1-c)*P_IF (k) +c*P_F (k-1)

[0127] In the formula, c is a coefficient, which is selected according to the specific implementation of the project.

[0128] The method proposed in the application can effectively identify abnormal signals in real time, suppress single-cycle and double-cycle interference, and is suitable for pressure signal filtering for surge judgment, through the combination of the amplitude filter module, the pulse filter module, and the inertial filter module.

[0129] The above is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A pressure signal filtering method for surge detection, characterized in that, The method includes: Acquire the pressure signal P after the high-pressure compressor of the engine; An amplitude limiting filter module is constructed. The pressure signal P is passed through the amplitude limiting filter module to obtain the pressure signal P_LF. The amplitude limiting filter module acquires the pressure value P. (k) Using the input as input, the steady-state value P_F2 of the pressure signal for the current period is calculated through the first inertial filter, the first amplitude-limiting filter, and the second inertial filter. (k) The second amplitude-limiting filter removes occasional large-amplitude disturbances that far exceed the steady-state value, where: The filtered pressure value P_F1 is obtained through the first inertial filter. (k) The filtering process is as follows: P_F1 (k) =(1-a)*P (k) +a*P_F1 (k-1) In the formula, a is a coefficient; subscript k represents the current period, and subscript k-1 represents the previous period; The filtering process of the first amplitude limiting filter is as follows: when At that time, the reconstructed pressure value P_RF is obtained through data reconstruction. (k) The reconstruction method is as follows: If P (k) - P_F1 (k) ≥0, P_RF (k) = (1 + A) * P_F1 (k) ; If P (k) - P_F1 (k) <0, P_RF (k) =(1 - A)*P_F1 (k) ; when At that time, P_RF (k) =P (k) In the formula, A is the threshold; The filtered pressure value P_F2 is obtained through a second inertial filter. (k) The filtering process is as follows: P_F2 (k) =(1-b)*P_RF (k) +b*P_F2 (k-1) In the formula, b is a coefficient; The filtering process of the second amplitude limiting filter is as follows: The second inertial filter yields the filtered pressure value P_F2. (k) With the collected value P (k) As input, the output is the pressure value P_LF after processing by the amplitude limiting filter module. (k) The process is as follows: when At that time, P_LF (k) =P_F2 (k-1) Otherwise P_LF (k) =P (k) ; In the formula, B is the threshold; Construct a pulse filtering module to obtain the pressure signal P_IF from the pressure signal P_LF; An inertial filter module is constructed, and the pressure signal P_IF is passed through the inertial filter module to obtain the pressure signal P_F.

2. The pressure signal filtering method for surge detection as described in claim 1, characterized in that, The pulse filtering module processes the pressure value P_LF using the amplitude limiting filtering module. (k) Using the input as input, the steady-state value P_F2 of the current period is obtained through the third inertial filter, the third amplitude-limiting filter, and the fourth inertial filter. (k) '; If P_LF (k) Exceeding the current period steady-state value P_F2 (k) If the signal exceeds a certain range, interference will occur or the engine will enter a surge abnormal state. Subsequently, based on the data from several subsequent cycles, further judgment will be made to determine the output value of the pulse filter and filter out single-cycle or double-cycle interference.

3. The pressure signal filtering method for surge detection as described in claim 2, characterized in that, The pressure signal value after the third inertial filtering process: P_F1' (k) =(1-a)*P_LF (k) +a*P_F1' (k-1) ; The filtering process of the third amplitude limiting filter is as follows: when At that time, the reconstructed pressure value P_RF' is obtained through data reconstruction. (k) The reconstruction method is as follows: If P_LF (k) - P_F1' (k) ≥ 0, P_RF' (k) = (1 + A) * P_F1' (k) ; If P (k) -P_F1 (k) <0, P_RF' (k) =(1 - A)*P_F1' (k) ; when At that time, P_RF' (k) =P_LF (k) ; The pressure signal value after the fourth inertial filtering process: P_F2' (k) =(1-b)*P_RF' (k) +b*P_F2' (k-1) 。 4. The pressure signal filtering method for surge detection as described in claim 3, characterized in that, The filtering process of the pulse filter is as follows: make P_state (k) The relative change in pressure; based on the values ​​of the two periods k-1 and k, determine whether the dynamic identifiers State_α and State_β of the pressure signal are valid. State_α is the judgment factor for entering pulse logic 1, and State_β is the judgment factor for entering pulse logic 2. The voting logic for State_α is shown in Table 1, and the voting logic for State_β is shown in Table 2. In the table, "1" indicates that it is valid and "0" indicates that it is invalid. P_α and P_β are dynamic discrimination thresholds, and K1*P_α and K2*P_β are data anomaly thresholds. Table 1 State_α State Judgment Logic Table 2 State_β State Judgment Logic Where K1*P_α≤P_state (k) <K2*P_β, and State_α (k-1) When = 0, execute the logic in Table 3; Table 3 Pulse Filtering Logic 1 Where, when P_state (k) ≥K2*P_β, and State_β (k-1) When = 0, execute the logic in Table 4; Table 4 Pulse Filtering Logic 2 When neither of the above two filtering logics is invoked: Pressure signal value after pulse filtering: P_IF (k) =P_LF (k) .

5. The pressure signal filtering method for surge detection as described in claim 4, characterized in that, The inertial filtering module filters out high-frequency components in the signal, making the signal moderately smooth. The process is as follows: Filtered pressure signal value: P_F (k) = (1-c)*P_IF (k) +c*P_F (k-1) In the formula, c is a coefficient.

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