Device and method for monitoring and diagnosing rotating speed state of aero-engine

Abstract

The invention provides a device and a method for monitoring and diagnosing the rotating speed state of an aero-engine. The device comprises an input protection and preprocessing unit, a signal isolation and conditioning unit and a data processing unit which are connected in sequence, the input protection and preprocessing unit receives a rotating speed signal output by a sensor, preprocesses the rotating speed signal and divides the signal into two paths; the signal isolation and conditioning unit adopts a square wave processing channel to shape the preprocessed first path of rotating speed signals into square waves, adopts an analog signal processing channel to convert the other path of rotating speed signals into digital signals, and then outputs the digital signals in an isolated manner; and the data processing unit calculates the rotating speed according to the square wave signal, performs amplitude analysis according to the digital signal, and diagnoses the state of the rotating speed sensor according to a preset truth table by synthesizing the rotating speed and the amplitude. Based on the device, the invention further provides an aero-engine rotating speed state monitoring and diagnosing method. According to the invention, on the basis of diagnosis logic of dual-channel cross validation, sensor disconnection, signal attenuation and channel hardware faults are effectively distinguished.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aero-engine state monitoring, and particularly relates to an aero-engine rotating speed state monitoring and diagnosing device and method. BACKGROUND

[0002] The rotating speed of an aero-engine is a key parameter reflecting its working state and has an important influence on flight safety. At present, rotating speed monitoring mainly adopts a scheme of a magneto-electric sensor combined with a rear-end signal processing circuit. The sensor senses the movement of the tooth groove of the engine rotor to output a sinusoidal signal, and the rotating speed is collected after being processed and calculated by the rear-end circuit.

[0003] As disclosed in the comparative file CN111122908B, a square wave test signal is additionally introduced into the sensor circuit, and whether the square wave test signal is correctly responded is judged to detect whether the sensor is disconnected. However, this method has the following disadvantages: the function is single, only two states of disconnection and normality can be judged, other common fault modes such as signal attenuation and processing channel failure cannot be distinguished, and the demand of fault root positioning for modern predictive maintenance cannot be met. Therefore, there is an urgent need in the field for an intelligent rotating speed monitoring device and method capable of distinguishing multiple faults in real time. SUMMARY

[0004] In order to solve the above technical problems, the present application provides an aero-engine rotating speed state monitoring and diagnosing device and method to solve the technical problem of insufficient fault mode distinguishing ability in the prior art.

[0005] To achieve the above-mentioned purpose, the following technical solutions are adopted in the present application: An aero-engine rotating speed state monitoring and diagnosing device, comprising: an input protection and preprocessing unit, a signal isolation and conditioning unit and a data processing unit connected in sequence; The input protection and preprocessing unit is used for receiving a rotating speed signal output by a rotating speed sensor, and pre-processing the rotating speed signal and dividing it into two paths, which are respectively output to a square wave processing channel and an analog signal processing channel of the signal isolation and conditioning unit connected in parallel; The signal isolation and conditioning unit adopts the square wave processing channel to shape the first path of the pre-processed rotating speed signal into a square wave output to the data processing unit, and adopts the analog signal processing channel to convert the other path of the pre-processed rotating speed signal into a digital signal and then isolate and output it to the data processing unit; The data processing unit is used for calculating the rotating speed according to the square wave signal, and performing amplitude analysis according to the isolated digital signal, and diagnosing the state of the rotating speed sensor by comprehensively considering the rotating speed and the amplitude and according to a pre-set truth table mapping rule; the state includes: normal operation, sensor disconnection, signal attenuation and square wave processing channel failure.

[0006] Further, the criterion for the data processing unit to diagnose the sensor state is: When the amplitude is continuously greater than or equal to the preset amplitude threshold value, and the square wave frequency is continuously higher than the preset frequency threshold value but not zero, it is diagnosed as normal operation; When the amplitude is continuously lower than the preset amplitude threshold value, and the square wave frequency is continuously zero, it is diagnosed as a broken wire of the speed sensor; When the amplitude is continuously lower than the preset amplitude threshold value but higher than zero, and the square wave frequency is normal, it is diagnosed as signal attenuation; When the amplitude is normal, but the square wave frequency is continuously zero, it is diagnosed as a fault of the square wave processing channel.

[0007] Further, the data processing unit is further configured to reconstruct a square wave signal based on the analog signal processing channel for another preprocessed speed signal when the speed sensor state is diagnosed as a fault of the square wave processing channel, and to continue to complete the update calculation of the speed by using the reconstructed square wave signal.

[0008] Further, the data processing unit is further configured to continuously learn the historical data of the amplitude and the square wave frequency when the speed sensor state is diagnosed as normal operation, and to dynamically adjust the preset amplitude threshold value and the preset frequency threshold value for fault diagnosis based on the learning result.

[0009] Further, the specific method for dynamically adjusting the preset amplitude threshold value and the preset frequency threshold value for fault diagnosis is to calculate the moving average and the moving standard deviation of the signal characteristic value within a preset time window, to calculate the preset amplitude threshold value and the preset frequency threshold value by using the moving average and the moving standard deviation, and by introducing the signal sensitivity.

[0010] Further, the device further comprises an output unit and a display unit; The output unit is configured to output the speed value and a state word containing a specific diagnosis state identifier; The display unit is configured to display the speed and differentiated alarm information.

[0011] Further, the input protection and preprocessing unit comprises an input protection module and a band-pass filter module; The input protection module comprises a first-stage clamping absorption network composed of a TVS tube, a gas discharge tube and a voltage-dependent resistor connected in parallel, for resisting high-voltage transient pulses; and a second-stage overcurrent protection circuit composed of a self-restoring fuse and a current-limiting resistor connected in series in the signal loop, for limiting abnormal current and achieving physical isolation when the overcurrent is continuous; The band-pass filter module uses a band-pass filter to filter out noise outside a specific frequency band in the signal output by the protection module.

[0012] Further, the square wave processing channel comprises a Schmitt trigger and a high-speed optocoupler isolator connected in sequence; The Schmitt trigger is used for shaping the preprocessed sinusoidal signal into a square wave; The high-speed optical coupling isolator is used for electrically isolating the shaped square wave and outputting to the data processing unit.

[0013] Further, the analog signal processing channel comprises an amplifier, an ADC converter and a digital isolator connected in sequence; The amplifier is used for amplifying the preprocessed sinusoidal signal; The ADC converter is used for sampling and converting the amplified signal into a digital signal; The digital isolator is used for electrically isolating the digital signal and outputting to the data processing unit.

[0014] The application further provides an aero-engine rotating speed state monitoring and diagnosing method, which is applied to the device and characterized by comprising the following steps. The rotating speed signal output by the rotating speed sensor is acquired, and the rotating speed signal is preprocessed and then divided into two paths; The first path of the preprocessed rotating speed signal is shaped into a square wave, and the other path of the preprocessed rotating speed signal is converted into a digital signal and then isolated and output; The rotating speed is calculated according to the square wave signal, the amplitude is analyzed according to the isolated and output digital signal, the rotating speed and the amplitude are comprehensively analyzed, and the rotating speed sensor state is diagnosed according to the preset true value table mapping rule; the state comprises normal operation, sensor disconnection, signal attenuation and square wave processing channel fault The effects provided in the summary are only the effects of the embodiments, and are not all the effects of the application; one of the above technical solutions has the following advantages or beneficial effects: The application provides an aero-engine rotating speed state monitoring and diagnosing device and method, and the device comprises an input protection and preprocessing unit, a signal isolation and conditioning unit and a data processing unit connected in sequence. The input protection and preprocessing unit is used for receiving a rotating speed signal of a rotating speed sensor output, and pre-processing the rotating speed signal and dividing the pre-processed rotating speed signal into two paths, and outputting the two paths to a square wave processing channel and an analog signal processing channel of the signal isolation and conditioning unit arranged in parallel; the signal isolation and conditioning unit adopts the square wave processing channel to shape the first path of the pre-processed rotating speed signal into a square wave output to the data processing unit, and adopts the analog signal processing channel to convert the other path of the pre-processed rotating speed signal into a digital signal and then isolate the digital signal and output the digital signal to the data processing unit; the data processing unit is used for calculating a rotating speed according to the square wave signal, and performing amplitude analysis according to the isolated digital signal, and diagnosing a rotating speed sensor state by comprehensively considering the rotating speed and the amplitude and according to a preset truth table mapping rule; the state includes: normal operation, sensor disconnection, signal attenuation, and square wave processing channel failure. Based on the aero-engine rotating speed state monitoring and diagnosing device, the application further provides an aero-engine rotating speed state monitoring and diagnosing method. Based on the diagnosis logic of the double-channel cross verification, the application can effectively distinguish the sensor disconnection, the signal attenuation and the channel hardware failure, and provide a clear guide for maintenance.

[0015] The prior art often leads to complete failure of the speed measurement function after diagnosing a specific failure (such as a signal processing channel failure), lacks the degradation operation capability in the failure condition, and cannot meet the functional safety requirement of the high-reliability aviation system. The application adopts the self-checking and reconstruction function, can quickly reconstruct the signal when the hardware channel fails, makes the device upgrade from diagnosing the failure to tolerating the failure, realizes the leap from the monitoring and diagnosis to the intelligent fault tolerance, and greatly improves the system availability.

[0016] The fixed diagnosis threshold in the prior art is difficult to adapt to the performance aging of the sensor and the change of the complex working condition, and is easy to cause false positives. The application combines the adaptive threshold adjustment and the reliability coefficient output, the system can adapt to the change, gives the confidence level of the diagnosis, significantly reduces the false positive rate, and makes the diagnosis result more reliable and the information more abundant. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The application provides a connection schematic diagram of an aero-engine rotating speed state monitoring and diagnosing device; Figure 2 The application provides a working flow chart of the aero-engine rotating speed state monitoring and diagnosing device; Figure 3 The application provides a connection block diagram of an input protection and preprocessing unit; Figure 4 The application provides a flow chart of an aero-engine rotating speed state monitoring and diagnosing method. DETAILED DESCRIPTION

[0018] For purposes of clarity, the present application will be described with reference to exemplary implementations herein. Various embodiments of the application are disclosed throughout the present disclosure. The following detailed description includes specific details for the purpose of providing an understanding of the various implementations of the application. However, it will be apparent to those skilled in the art that the application can be practiced without these specific details. In some instances, well-known structures and processes have not been described in detail in order to avoid obscuring the understanding of the present application. The following detailed description is not intended to limit the application. To the contrary, the following detailed description includes specific implementations of the present application and claims priority to the broadest possible scope of the application.

[0019] Embodiment 1 Embodiment 1 of the present application proposes an aero-engine rotating speed state monitoring and diagnosing device, which is used to solve the problems of insufficient fault mode distinguishing ability, lack of fault tolerance ability and false alarm caused by fixed diagnosing threshold in prior art.

[0020] Figure 1 A connection schematic diagram of the aero-engine rotating speed state monitoring and diagnosing device proposed by Embodiment 1 of the present application is provided; the device comprises: an input protection and preprocessing unit, a signal isolation and conditioning unit and a data processing unit connected in sequence; The input protection and preprocessing unit is used to receive the rotating speed signal output by the rotating speed sensor, and divide the rotating speed signal into two paths after preprocessing, and output the two paths to the square wave processing channel and the analog signal processing channel of the signal isolation and conditioning unit arranged in parallel respectively; The signal isolation and conditioning unit adopts the square wave processing channel to shape the first path of the preprocessed rotating speed signal into square wave output to the data processing unit, and adopts the analog signal processing channel to convert the other path of the preprocessed rotating speed signal into digital signal and then isolate and output to the data processing unit; The data processing unit is used to calculate the rotating speed according to the square wave signal, and perform amplitude analysis according to the isolated digital signal, and diagnose the rotating speed sensor state by comprehensively considering the rotating speed and the amplitude and according to the preset truth table mapping rule; the state includes: normal operation, sensor disconnection, signal attenuation and square wave processing channel fault.

[0021] The device further comprises an output unit and a display unit; The output unit is used to output the rotating speed value and the state word containing specific diagnosing state identifier; The display unit is used to display the rotating speed and the differentiated alarm information.

[0022] Figure 2The application discloses an aero-engine rotating speed state monitoring and diagnosing device, and relates to the technical field of aero-engine rotating speed state monitoring and diagnosing devices. Figure 3 The input protection and preprocessing unit includes a first-stage clamping absorption network composed of a TVS tube, a gas discharge tube and a voltage-dependent resistor in parallel connection, which is used for resisting high-voltage transient pulses, and a second-stage overcurrent protection circuit composed of a self-restoring fuse and a current-limiting resistor in series connection in a signal loop, which is used for limiting abnormal current and realizing physical isolation when continuous overcurrent occurs.

[0023] The first-stage clamping absorption network is used for limiting the voltage peak value in a safe range that can be borne by the subsequent circuit, and protecting the fragile band-pass filter.

[0024] The second-stage protection network outputs a "clean" signal subjected to high-voltage transient suppression and overcurrent protection, and sends the signal to the subsequent band-pass filter circuit for processing.

[0025] The band-pass filter is used for filtering out noise outside a specific frequency band in the signal output by the protection module.

[0026] The reason for setting the cut-off frequency of the second-order high-pass filter to 50 Hz is that: The output voltage frequency f (Hz) of the magneto-electric sensor is proportional to the engine rotating speed N (RPM) and the number of teeth Z of the speed measuring gear, and the relationship is f=(N×Z) / 60.

[0027] Assuming the engine ground idle speed is about 3000 RPM, and the gear tooth number Z = 60, the corresponding frequency is (3000 x 60) / 60 = 3000 Hz. This is much higher than 50 Hz.

[0028] However, there might be a windmill state of the engine, i.e. after air stop, relying on air flow to spin or start process, the speed might be as low as a few hundred RPM. With 500 RPM, Z = 60, f = (500 x 60) / 60 = 500 Hz. Even at this extremely low speed, the signal frequency (500 Hz) is much higher than the high-pass cutoff frequency of 50 Hz, and can pass through without attenuation.

[0029] Therefore, choosing 50 Hz ensures that in the entire engine speed range, the useful speed signal frequency components will not be filtered out.

[0030] Suppress typical low-frequency noise: 50 Hz or 400 Hz interference from the on-board AC power supply system is common; low-frequency mechanical vibration of the engine may be picked up by the sensor, producing low-frequency noise; due to temperature changes or electromagnetic interference, the sensor output may have a slow DC offset or very low-frequency drift. The 50 Hz high-pass characteristic can effectively attenuate or eliminate these low-frequency interference and drift, preventing them from interfering with subsequent signal conditioning (especially square wave shaping), ensuring the stability of the measurement.

[0031] The reason for setting the cutoff frequency of the second-order low-pass filter in this application to 20 Hz is: Cover the highest working speed and leave a margin: Assuming the maximum working speed of the engine is 15000 RPM, and the gear tooth number Z = 60, the corresponding frequency is (15000 x 60) / 60 = 15000 Hz (15 kHz). Choosing a low-pass cutoff frequency of 20 kHz can ensure that all useful signal frequencies (0.5 kHz ~ 15 kHz) including the highest speed are within the passband of the filter and will not cause signal attenuation. And 20 kHz provides a margin of about 5 kHz for the highest signal frequency (15 kHz), which takes into account the possibility of temporary over-speed of the engine, more gear teeth, etc. actual situation, to ensure the robustness of the system.

[0032] Suppress high frequency noise and anti-aliasing: Onboard switching power supply and power electronic equipment will produce tens of kHz to hundreds of kHz high frequency switching noise; communication systems and radar will produce high frequency electromagnetic interference; for analog signal processing channels, ADC must be anti-aliasing filtered before sampling. According to the Nyquist sampling theorem, if the sampling frequency of ADC is Fs, all frequency components higher than Fs / 2 must be filtered out. Assuming the ADC sampling rate is 100kHz, then Fs / 2=50kHz. Set a 20kHz sharp low-pass filter (fourth-order Butterworth), a strong "isolation band" can be formed between the signal band (15kHz) and the folding frequency (50kHz), greatly attenuating any high-frequency noise that may cause aliasing, ensuring the quality of ADC sampling.

[0033] Optimize square wave signal quality: For square wave processing channels, filtering out high frequency noise can prevent high frequency glitches on the sine signal from causing the Schmidt trigger to produce false multiple flips, resulting in a clear, clean and stable square wave, which is essential for accurate frequency measurement.

[0034] Therefore, the determination of the two cutoff frequencies of 50Hz and 20kHz is an optimal engineering compromise based on a full understanding of the signal frequency range and noise sources. It ensures that the signal-to-noise ratio of the system is maximized while preserving all useful signals, laying a solid foundation for high-precision speed measurement and reliable diagnosis in the backend.

[0035] The signal isolation and conditioning unit includes a square wave processing channel and an analog signal processing channel. The square wave processing channel includes a Schmidt trigger and an optocoupler isolation circuit connected in sequence, for shaping the sine signal into a square wave and performing electrical isolation.

[0036] The analog signal processing channel includes an instrument amplifier, an ADC converter and a digital isolator connected in sequence, for amplifying, sampling and converting the small voltage sine signal into a digital signal, and then coupling it to the input interface of the data processing unit.

[0037] The amplifier is used to amplify the preprocessed sine signal; The ADC converter is used to sample and convert the amplified signal into a digital signal; The digital isolator is used to electrically isolate the digital signal and output it to the data processing unit.

[0038] In this application, the data processing unit uses a single-chip microcomputer or MCU to synchronously collect the ADC signal amplitude and square wave signal frequency at a fixed period. Specifically: The input capture function of the timer is used to accurately measure the period of the square wave and calculate the instantaneous frequency; the ADC is used to read the converted digital quantity and calculate the peak value or effective value of the signal in a period as the amplitude value; the timer is used to ensure that the frequency and amplitude information are aligned in time, laying the foundation for subsequent correlation diagnosis.

[0039] In this application, when the amplitude value is greater than or equal to the preset amplitude threshold value and the square wave frequency is continuously higher than the preset frequency threshold value but not zero, it is diagnosed as normal operation; When the amplitude value is continuously lower than the preset amplitude threshold value and the square wave frequency is continuously zero, it is diagnosed as a broken wire of the speed sensor; When the amplitude value is continuously lower than the preset amplitude threshold value but higher than zero and the square wave frequency is normal, it is diagnosed as signal attenuation; When the amplitude value is normal but the square wave frequency is continuously zero, it is diagnosed as a square wave processing channel failure.

[0040] A truth table is preset in the data processing unit to define the mapping relationship between the state combination and the diagnosis conclusion, as shown in Table 3 below: Table Three: Truth Table

[0041] The data processing unit is also used to reconstruct a square wave signal based on the analog signal processing channel for another preprocessed speed signal when the speed sensor state is diagnosed as a square wave processing channel failure, and to continue to complete the speed update calculation using the reconstructed square wave signal.

[0042] The application analyzes the sine wave sampled by the ADC in real time, and generates a digital square wave with steep edges in the software when the voltage zero crossing point is detected or a certain amplitude level is reached. The reconstructed square wave signal is used to calculate the speed, and in the case of failure of the square wave processing channel hardware, the system can still use the data provided by the analog signal processing channel to maintain the core speed measurement function, from the "failure" state to the "degraded operation" state, greatly improving the survival ability of the system.

[0043] The data processing unit is also used to continuously learn the historical data of the amplitude value and the square wave frequency when the speed sensor state is diagnosed as normal operation, and dynamically adjust the preset amplitude threshold value and the preset frequency threshold value used for fault diagnosis based on the learning result. The specific method of dynamically adjusting the preset amplitude threshold value and the preset frequency threshold value used for fault diagnosis is: calculating the moving average and moving standard deviation of the signal characteristic value in the preset time window, using the moving average and moving standard deviation, and introducing the signal sensitivity to calculate the preset amplitude threshold value and the preset frequency threshold value. The detailed process includes: An ADC signal amplitude and square wave signal frequency first-in-first-out buffer is established respectively, and the buffer length is determined by the preset time window Determination, to cover the typical engine operating cycle; when the new sampling data input, synchronous storage corresponding to the buffer and remove the oldest data point; The moving average value and the moving standard deviation of the signal feature are calculated in real time by using the recursive algorithm: The moving average value is calculated by the formula: ; ; Wherein, is the moving average value of the frequency of the current period; is the moving average value of the frequency of the last period; is the moving average value of the amplitude of the current period; is the moving average value of the amplitude of the last period; is the amplitude and frequency of the current sampling period, respectively; is the old amplitude and old frequency removed from the time window, respectively.

[0044] The moving standard deviation is calculated based on the recursive sum of squares:

[0045]

[0046] ; ; is the sum of squares of the amplitude data in the buffer, is the sum of squares of the amplitude data in the last period, is the sum of squares of the frequency data in the buffer, is the sum of squares of the frequency data in the last period; is the standard deviation of the amplitude data in the buffer; is the standard deviation of the frequency data in the buffer; represents the preset time window; According to the moving average value and the moving standard deviation, the fault diagnosis threshold is dynamically adjusted:

[0047]

[0048] Wherein, is the preset amplitude threshold, is the preset frequency threshold, is the configurable amplitude sensitivity coefficient; is the configurable frequency sensitivity coefficient.

[0049] Double protection is implemented on the output threshold: setting the lower limit threshold of the amplitude and a lower frequency threshold for ensuring that the dynamic threshold is not lower than a safety margin.

[0050] The device also comprises an output unit and a display unit; the output unit is used for outputting the rotating speed value and a state word containing a specific diagnosis state identifier; diagnosis conclusion, rotating speed value, reliability coefficient and other information are packaged into a data frame (for example: ID 0x00000123, the data section contains rotating speed and state word) according to a predefined CANaerospace protocol format.

[0051] The display unit is used for displaying rotating speed and differential alarm information. The data frame is sent to the vehicle bus network through the CAN bus output interface. At the same time, the display alarm module is driven according to the diagnosis conclusion, and differential alarm (such as broken line-red flashing, attenuation-yellow pre-warning, channel fault-red constant) is executed.

[0052] The aviation engine rotating speed state monitoring and diagnosis device provided by the application forms a closed-loop intelligent monitoring system integrating synchronous acquisition, intelligent diagnosis, adaptive learning and fault tolerance.

[0053] The aviation engine rotating speed state monitoring and diagnosis device provided by the embodiment 1 of the application can effectively distinguish sensor broken line, signal attenuation and channel hardware fault based on the diagnosis logic of double-channel cross verification, and provides clear guidance for maintenance.

[0054] The aviation engine rotating speed state monitoring and diagnosis device provided by the embodiment 1 of the application adopts self-checking and reconstruction functions, can quickly reconstruct signals when the hardware channel fails, and upgrades the device from diagnosing faults to diagnosing and tolerating faults, realizes the leap from monitoring and diagnosis to intelligent fault tolerance, and greatly improves the system availability.

[0055] The aviation engine rotating speed state monitoring and diagnosis device provided by the embodiment 1 of the application combines adaptive threshold adjustment and reliability coefficient output, the system can adapt to changes, and gives the confidence level of diagnosis, significantly reduces the false alarm rate, and makes the diagnosis result more reliable and the information more abundant.

[0056] Embodiment 2 Based on the aviation engine rotating speed state monitoring and diagnosis device provided by the embodiment 1 of the application, the embodiment 2 of the application further provides an aviation engine rotating speed state monitoring and diagnosis method. Figure 4 The flow chart of the aviation engine rotating speed state monitoring and diagnosis method provided by the embodiment 2 of the application is shown.

[0057] The ADC signal amplitude processed by the analog signal processing channel and the square wave signal frequency processed by the square wave processing channel are synchronously collected according to a fixed period; comparing the amplitude of the ADC signal with a preset amplitude threshold value: if the amplitude of the ADC signal is continuously lower than the threshold value, it is marked as "amplitude abnormality"; if the amplitude of the ADC signal is continuously higher than the threshold value, it is marked as "amplitude normality"; at the same time, the frequency of the square wave signal is compared with a preset fault threshold value: if the frequency of the square wave signal is continuously lower than the threshold value or completely disappears, it is marked as "frequency abnormality"; if the frequency of the square wave signal is continuously higher than the threshold value, it is marked as "frequency normality".

[0058] The output state is continuously monitored, and when the combination of the amplitude abnormality state and the frequency abnormality state continuously remains unchanged for a preset time length, a final diagnostic conclusion is output according to a pre-defined truth table of multiple fault types. The diagnostic conclusion is converted into a state word in a pre-defined format and uploaded through a CAN bus interface, the state word contains an identification code for distinguishing different fault types, and a display alarm module is driven to perform differentiated alarm operations according to the diagnostic conclusion.

[0059] The application is also used for reconstructing a square wave signal based on an analog signal processing channel when the state of the speed sensor is diagnosed as a square wave processing channel fault, and using the reconstructed square wave signal to continue the update calculation of the speed.

[0060] The sine wave sampled by the ADC is analyzed in real time, and a digital square wave with a steep edge is generated in the software when the voltage zero-crossing point is detected or a certain amplitude level is reached. The reconstructed square wave signal is used to calculate the speed, and in the case of failure of the square wave processing channel hardware, the system can still use the data provided by the analog signal processing channel to maintain the core speed measurement function, from the "fault" state to the "degraded operation" state, greatly improving the survivability of the system.

[0061] When the state of the speed sensor is diagnosed as normal operation, the historical data of the amplitude and the square wave frequency are continuously learned, and the preset amplitude threshold value and the preset frequency threshold value used for fault diagnosis are dynamically adjusted based on the learning result. In the normal operation state, the algorithm continuously calculates the moving average and the standard deviation of the amplitude and the frequency, and dynamically updates the fault threshold value, so that the system can adapt to the slow aging of the sensor performance. According to the signal-to-noise ratio of the current signal, the continuity of the state stability and other factors, the reliability of the current diagnostic conclusion is calculated.

[0062] The specific method for dynamically adjusting the preset amplitude threshold value and the preset frequency threshold value used for fault diagnosis is: calculating the moving average and the moving standard deviation of the signal characteristic value within a preset time window, using the moving average and the moving standard deviation, and introducing the signal sensitivity to calculate the preset amplitude threshold value and the preset frequency threshold value.

[0063] The embodiment 2 of the present application further provides an aero-engine rotating speed state monitoring and diagnosing method, which is applied to the aero-engine rotating speed state monitoring and diagnosing device provided in the embodiment 1 of the present application, and the related part of the aero-engine rotating speed state monitoring and diagnosing method provided in the embodiment 2 of the present application can be referred to the detailed description of the corresponding part of the aero-engine rotating speed state monitoring and diagnosing device provided in the embodiment 1 of the present application, which will not be repeated here.

[0064] It should be noted that, in this document, the terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device comprising a series of elements inherently includes the elements. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, the above technical solutions provided in the embodiments of the present application have not been described in detail, which are consistent with the implementation principles of the corresponding technical solutions in the prior art, so as not to be too repetitive.

[0065] The above describes the specific embodiments of the present application in combination with the accompanying drawings, but is not a limitation on the protection scope of the present application. Based on the above description, those skilled in the art can make other different forms of modifications or changes. Here, it is not necessary and impossible to enumerate all the embodiments. Various modifications or changes made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. An engine speed condition monitoring diagnostic apparatus, characterized by, The device comprises: an input protection and preprocessing unit, a signal isolation and conditioning unit, and a data processing unit connected in sequence; the input protection and preprocessing unit is configured to receive a rotational speed signal output by a rotational speed sensor, and to preprocess the rotational speed signal and divide it into two paths, which are output to a square wave processing channel and an analog signal processing channel of the signal isolation and conditioning unit in parallel; the signal isolation and conditioning unit is configured to reshape the first path of the preprocessed rotational speed signal into a square wave output to the data processing unit by using the square wave processing channel, and to convert the other path of the preprocessed rotational speed signal into a digital signal and then isolate the digital signal output to the data processing unit by using the analog signal processing channel; the data processing unit is configured to calculate a rotational speed according to the square wave signal, to perform amplitude analysis according to the isolated digital signal, to integrate the rotational speed and the amplitude, and to diagnose a state of the rotational speed sensor according to a preset mapping rule of a truth table; the state includes: normal operation, sensor disconnection, signal attenuation, and square wave processing channel failure.

2. The apparatus of claim 1, wherein, The criteria for the data processing unit to diagnose the state of the sensor are as follows: when the amplitude is continuously greater than or equal to a preset amplitude threshold value, and the square wave frequency is continuously higher than a preset frequency threshold value but not zero, the state is diagnosed as normal operation; when the amplitude is continuously lower than the preset amplitude threshold value, and the square wave frequency is continuously zero, the state is diagnosed as sensor disconnection; when the amplitude is continuously lower than the preset amplitude threshold value but higher than zero, and the square wave frequency is normal, the state is diagnosed as signal attenuation; when the amplitude is normal, but the square wave frequency is continuously zero, the state is diagnosed as square wave processing channel failure.

3. The apparatus of claim 2, wherein, The data processing unit is further configured to reconstruct a square wave signal based on the analog signal processing channel for the other path of the preprocessed rotational speed signal when the state of the rotational speed sensor is diagnosed as square wave processing channel failure, and to continue to complete the update calculation of the rotational speed by using the reconstructed square wave signal.

4. The apparatus of claim 2, wherein, The data processing unit is further configured to continuously learn historical data of the amplitude and the square wave frequency when the state of the rotational speed sensor is diagnosed as normal operation, and to dynamically adjust the preset amplitude threshold value and the preset frequency threshold value for fault diagnosis based on the learning result.

5. The apparatus of claim 4, wherein, The specific method for dynamically adjusting the preset amplitude threshold value and the preset frequency threshold value for fault diagnosis is as follows: calculating a moving average value and a moving standard deviation of a signal characteristic value within a preset time window, and calculating the preset amplitude threshold value and the preset frequency threshold value by using the moving average value and the moving standard deviation and introducing a signal sensitivity.

6. The apparatus of claim 1, wherein, The device further comprises an output unit and a display unit; the output unit is configured to output a rotational speed value and a state word containing a specific diagnosis state identifier; the display unit is configured to display the rotational speed and differentiated alarm information.

7. The apparatus of claim 1, wherein, The input protection and preprocessing unit comprises an input protection module and a band-pass filter module; the input protection module comprises a first-stage clamping absorption network composed of a TVS tube, a gas discharge tube, and a voltage-dependent resistor connected in parallel, which is configured to resist high-voltage transient pulses; and a second-stage overcurrent protection circuit composed of a self-restoring fuse and a current-limiting resistor connected in series in a signal loop, which is configured to limit abnormal current and achieve physical isolation when the overcurrent is continuous; the band-pass filter module uses a band-pass filter to filter out noise outside a specific frequency band in the signal output by the protection module.

8. The apparatus of claim 1, wherein, The square wave processing channel comprises a Schmitt trigger and a high-speed optocoupler isolator connected in sequence; The Schmitt trigger is used for shaping the preprocessed sinusoidal signal into a square wave; The high-speed optocoupler isolator is used for electrically isolating the shaped square wave and outputting to a data processing unit.

9. The apparatus of claim 1, wherein, The analog signal processing channel comprises an amplifier, an ADC converter and a digital isolator connected in sequence; The amplifier is used for amplifying the preprocessed sinusoidal signal; The ADC converter is used for sampling and converting the amplified signal into a digital signal; The digital isolator is used for electrically isolating the digital signal and outputting to a data processing unit.

10. An aeroengine rotating speed condition monitoring and diagnosing method applied to the device as claimed in any one of claims 1-9, characterized in that, The method comprises the following steps: Obtaining a rotation speed signal output by a rotation speed sensor, and preprocessing the rotation speed signal and dividing it into two paths; Shaping the preprocessed first path rotation speed signal into a square wave; Isolating and outputting the preprocessed other path rotation speed signal after being converted into a digital signal; Calculating the rotation speed according to the square wave signal, performing amplitude analysis according to the isolated and output digital signal, comprehensively analyzing the rotation speed and the amplitude, and diagnosing the rotation speed sensor state according to a preset truth table mapping rule; the state comprises normal operation, sensor disconnection, signal attenuation and square wave processing channel failure.

Images