A combined test method for solenoid valve operation stability and sticking detection

Abstract

The present invention relates to the technical field of electromagnetic actuator state monitoring, and specifically to a combined testing method for stability and stuck detection during the operation of a solenoid valve, comprising the following steps: S1: synchronously collecting coil current signals, valve core displacement signals, and outlet pressure pulsation signals; S2: converting the current signals collected in S1 into equivalent electromagnetic force waveforms, velocity-acceleration trajectories, and pressure gradient curves; S3: extracting the electromagnetic force zero-crossing distortion rate, the inertia mutation point of the velocity-acceleration trajectory, and the oscillation attenuation coefficient of the pressure gradient curve; S4: calculating the time offset to generate a primary stuck warning; S5: obtaining a stability degradation index; and S6: outputting a stuck-instability coupled fault conclusion when the primary stuck warning is triggered and the stability degradation index exceeds a dynamic threshold. By integrating multidimensional signal features with a dual-criteria judgment mechanism, the present invention achieves high-precision, real-time identification of solenoid valve stuck and stability degradation faults.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic actuator state monitoring, and in particular to a combined testing method for stability and sticking detection during operation of an electromagnetic valve. Background Art

[0002] As a key component in fluid control systems, the solenoid valve's operating stability directly affects the system's response accuracy and safety performance. Under high-speed switching or complex load conditions, the solenoid valve's valve core movement is affected by the coupling of multiple factors such as electromagnetic driving force, fluid reaction force and friction resistance, and is prone to abnormal behaviors such as response delay, movement interruption or incomplete closure. Especially during continuous opening and closing, some solenoid valves have short-term stuck phenomena caused by structural aging, coil performance fluctuations or insufficient system damping. Such faults are usually sudden and non-repetitive, and are difficult to accurately identify through conventional static testing or single physical quantity monitoring methods. In addition, slight unstable behaviors during the valve core movement process often manifest themselves in the form of waveform distortion, sudden changes in inertia or residual fluid disturbances, causing potential interference to subsequent control processes and even leading to frequent false triggering or uncontrolled shutdown of the system.

[0003] Existing solenoid valve detection methods mostly rely on single-channel determination of displacement signals or current waveforms. These methods lack in-depth understanding of the temporal response relationships and coupling characteristics between multidimensional signals, making it difficult to achieve real-time identification of the combined characteristics of "mild sticking and mild instability" during operation, resulting in the inability to provide early warning for some faults. Therefore, a combined testing method for solenoid valve stability and sticking detection during operation is proposed to address this issue. Summary of the Invention

[0004] Based on the above objectives, the present invention provides a combined testing method for stability and sticking detection during the operation of a solenoid valve.

[0005] A combined testing method for stability and sticking detection of a solenoid valve during operation comprises the following steps:

[0006] S1: During the solenoid valve driving stage, the coil current signal, valve core displacement signal and outlet pressure pulsation signal are synchronously collected;

[0007] S2: Convert the current signal collected by S1 into an equivalent electromagnetic force waveform, the displacement signal into a velocity-acceleration trajectory, and the outlet pressure pulsation signal into a pressure gradient curve;

[0008] S3: Based on the data converted by S2, the zero-crossing distortion rate of the electromagnetic force, the inertia mutation point of the velocity-acceleration trajectory, and the oscillation attenuation coefficient of the pressure gradient curve are extracted;

[0009] S4: Calculate the time offset between the inertia mutation point in S3 and the electromagnetic force zero-crossing distortion rate. When the offset exceeds the theoretical response time window of the valve core movement, a primary jam warning is generated.

[0010] S5: Multiply the oscillation attenuation coefficient in S3 by the harmonic distortion of the electromagnetic force waveform to obtain the stability degradation index;

[0011] S6: When the primary stuck warning is triggered and the stability degradation index exceeds the dynamic threshold, the conclusion of the stuck-instability coupled fault is output.

[0012] Optionally, the S1 specifically includes:

[0013] S11: When the solenoid valve receives the driving command signal, the coil current in the driving circuit is sampled in real time through the current sensor, and the sampling result is output to the current channel of the data acquisition card;

[0014] S12: A laser displacement sensor is arranged axially opposite to the center of the solenoid valve core to record the axial displacement of the valve core in real time during the driving process, and the displacement signal is synchronously transmitted to the displacement channel of the data acquisition card;

[0015] S13: A piezoelectric pressure sensor is installed on the outlet pipe of the solenoid valve. The sensor sensitivity is not less than 10mV / kPa. It is used to sense the pressure fluctuation caused by the valve core movement in real time and transmit the outlet pressure pulsation signal in the form of analog voltage to the pressure channel of the data acquisition card;

[0016] S14: The data acquisition card synchronously acquires three types of signals: current, displacement and pressure under a preset unified sampling clock.

[0017] Optionally, the S2 specifically includes:

[0018] S21: Based on the coil current signal collected by S1 and the structural inductance model of the solenoid valve, the current signal is converted into the corresponding equivalent electromagnetic force waveform ;

[0019] S22: Based on the acquired valve core displacement signal, the first-order and second-order derivative calculation methods are used to obtain the velocity and acceleration trajectories respectively, and a complete velocity-acceleration time series is constructed;

[0020] S23: Based on the collected outlet pressure pulsation signal, a time-order derivative method is used to obtain the pressure change rate, and then a pressure gradient curve reflecting the fluid disturbance process caused by the valve core action is constructed.

[0021] Optionally, the S3 specifically includes:

[0022] S31: Perform zero-crossing detection on the equivalent electromagnetic force waveform, intercept each zero-crossing segment, and calculate the asymmetric amplitude difference between the positive and negative half-cycles of the waveform to obtain the electromagnetic force zero-crossing distortion rate;

[0023] S32: Locate the velocity extreme value in the velocity-acceleration trajectory, monitor the instantaneous reversal of the acceleration direction before and after the extreme value, and calibrate the position that meets the valve core movement emergency stop-reverse characteristic as the inertia mutation point;

[0024] S33: Perform main peak and attenuation peak detection on the pressure gradient curve, extract the amplitude and time interval of each peak, and obtain the oscillation attenuation coefficient reflecting the fluid disturbance attenuation ability by fitting its decreasing trend.

[0025] Optionally, the S31 specifically includes:

[0026] S311: Equivalent electromagnetic force waveform Perform first-order sign change detection, traverse the sign changes between adjacent sampling points, and when . If the waveform between two points is continuous, the point is determined to be a zero-crossing point. , and As the center, the number of fixed sampling points is extended forward and backward Construct a local zero-crossing segment to obtain a time domain interval;

[0027] S312: In each zero-crossing segment, separate the positive half-cycle segment and the negative half-cycle segment of the waveform, and calculate the maximum amplitude of the positive and negative parts in the segment respectively, and set them as and , and calculate the amplitude index of the zero-crossing section based on this ;

[0028] S313: Normalize and average the amplitude difference indicators of all zero-crossing sections to calculate the electromagnetic force zero-crossing distortion rate .

[0029] Optionally, the S32 specifically includes:

[0030] S321: In the velocity-acceleration trajectory, based on the velocity value change trend of adjacent time points, identify the local velocity maximum or minimum. Specifically, when the velocity value at a certain time point is higher than the velocity values ​​of the adjacent time points before and after it, or lower than the velocity values ​​of the adjacent time points before and after it, the time point is determined to be a velocity extreme point.

[0031] S322: With the velocity extreme point as the center, a fixed time window is expanded before and after it, and acceleration data within the time window is extracted; when the acceleration values ​​before and after the velocity extreme point are respectively positive and negative, or respectively negative and positive, the sign of the acceleration changes suddenly;

[0032] S323: Calculate the acceleration change rate of the symmetrical time positions before and after the velocity extreme point. If the acceleration change rate exceeds a preset mutation determination threshold, mark the velocity extreme point as an inertia mutation point.

[0033] Optionally, the S33 specifically includes:

[0034] S331: Analyze the sign change of the first-order derivative of the pressure gradient curve to identify the time point and amplitude of the main peak, and then detect each local maximum and its time position in ascending time order until the curve oscillation amplitude drops below the noise threshold, completing the peak sequence extraction;

[0035] S332: Calculate the amplitude ratio for each extracted attenuation peak With time interval , and Composition of attenuation feature point set;

[0036] S333: Establishing an exponential decay model based on a decay feature point set , and the least square method is used to solve the attenuation coefficient, and then the oscillation attenuation coefficient reflecting the fluid disturbance attenuation ability is obtained .

[0037] Optionally, the S4 specifically includes:

[0038] S41: Select a time point from the inertia mutation points extracted in S3 , and retrieve the most recent electromagnetic force zero-crossing time in its adjacent time window , calculate the time offset between the two ;

[0039] S42: Set the theoretical response time window threshold ;

[0040] S43: For all To judge, when there is any set of offsets that meet When the valve core is considered to be slow to respond to the drive signal, a primary sticking warning signal is generated.

[0041] Optionally, the S5 specifically includes:

[0042] S51: Perform fast Fourier transform on the equivalent electromagnetic force waveform obtained in S2 to obtain its frequency domain representation, extract the fundamental frequency component and several subsequent harmonic components, and calculate the harmonic distortion of the electromagnetic force waveform. ;

[0043] S52: The oscillation attenuation coefficient calculated in S3 and harmonic distortion Multiplying them together, we get the stability degradation index that characterizes the degree of nonlinear coupling between the electromagnetically modulated fluid response and the drive. .

[0044] Optionally, the S6 specifically includes:

[0045] S61: Real-time monitoring of the primary jam warning result generated in S4. When a jam warning signal is triggered in any detection cycle, it is determined that there is a risk of drive-response delay.

[0046] S62: Simultaneously read the stability degradation index calculated in S5 and compare it with the dynamic threshold value set according to the current working conditions. Comparison, if both the primary jam warning has been triggered and the stability degradation index is greater than the dynamic threshold When these two conditions are met, the output is a stuck-instability coupled fault judgment conclusion.

[0047] Beneficial effects of the present invention:

[0048] The present invention synchronously collects multi-channel signals such as current, displacement and pressure, and converts them into equivalent electromagnetic force waveforms, velocity-acceleration trajectories and pressure gradient curves respectively, and then extracts the electromagnetic force zero-crossing distortion rate, inertia mutation point and oscillation attenuation coefficient, realizing a multi-dimensional fusion analysis of electromagnetic drive response, structural motion characteristics and fluid disturbance behavior, and enhancing the ability to identify early abnormal behavior during the operation of the solenoid valve.

[0049] The present invention, by constructing a sticking warning mechanism based on time offset and a stability degradation index based on harmonic distortion and fluid attenuation characteristics, and outputting a stuck-instability coupled fault conclusion through dual-criteria linkage, can effectively improve the sensitivity and judgment accuracy of dynamic faults of solenoid valves, and has good real-time performance, scalability and engineering adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 Schematic diagram of a joint testing method according to an embodiment of the present invention;

[0052] Figure 2 Schematic diagram of the process of extracting three key parameters according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It is also noted that, to provide a more detailed description, the following embodiments are best and preferred embodiments, and those skilled in the art may employ alternative methods for implementing certain known technologies. Furthermore, the accompanying drawings are intended only to provide a more detailed description of the embodiments and are not intended to limit the present invention.

[0054] like Figure 1-Figure 2 As shown, a combined testing method for stability and sticking detection of a solenoid valve during operation includes the following steps:

[0055] S1: During the solenoid valve driving stage, the coil current signal, valve core displacement signal and outlet pressure pulsation signal are synchronously collected;

[0056] S2: Convert the current signal collected by S1 into an equivalent electromagnetic force waveform, the displacement signal into a velocity-acceleration trajectory, and the outlet pressure pulsation signal into a pressure gradient curve;

[0057] S3: Based on the data converted by S2, the zero-crossing distortion rate of the electromagnetic force, the inertia mutation point of the velocity-acceleration trajectory, and the oscillation attenuation coefficient of the pressure gradient curve are extracted;

[0058] S4: Calculate the time offset between the inertia mutation point in S3 and the electromagnetic force zero-crossing distortion rate. When the offset exceeds the theoretical response time window of the valve core movement, a primary jam warning is generated.

[0059] S5: Multiply the oscillation attenuation coefficient in S3 by the harmonic distortion of the electromagnetic force waveform to obtain the stability degradation index;

[0060] S6: When the primary stuck warning is triggered and the stability degradation index exceeds the dynamic threshold, the conclusion of the stuck-instability coupled fault is output.

[0061] S1 specifically includes:

[0062] S11: When the solenoid valve receives the driving command signal, the coil current in the driving circuit is sampled in real time through the current sensor. The sampling frequency is set to 50kHz, and the sampling result is output to the current channel of the data acquisition card.

[0063] S12: A laser displacement sensor is placed axially facing the center of the solenoid valve core. The sensor's ranging accuracy is no higher than 10 μm. The axial displacement of the valve core during the driving process is recorded in real time, and the displacement signal is synchronously transmitted to the displacement channel of the data acquisition card via the RS485 bus.

[0064] S13: A piezoelectric pressure sensor is installed on the outlet pipe of the solenoid valve. The sensor sensitivity is not less than 10mV / kPa. It is used to sense the pressure fluctuation caused by the valve core movement in real time and transmit the outlet pressure pulsation signal in the form of analog voltage to the pressure channel of the data acquisition card;

[0065] S14: The data acquisition card synchronously acquires three types of signals: current, displacement, and pressure under a preset unified sampling clock. The acquired data is cached and marked according to the timestamp to ensure the consistency of subsequent data fusion and analysis. The above steps achieve high-precision, low-latency synchronous acquisition of the three types of key signals in the solenoid valve drive response process through a unified sampling frequency and synchronous control mechanism, providing a reliable raw data foundation for the subsequent effective conversion and feature extraction of electromagnetic force waveforms, velocity-acceleration trajectories, and pressure gradient curves.

[0066] S2 specifically includes:

[0067] S21: Based on the coil current signal collected by S1 and the structural inductance model of the solenoid valve, the current signal is converted into the corresponding equivalent electromagnetic force waveform Specifically, the change in electromagnetic force over time is calculated by the functional relationship between the internal inductance of the solenoid valve and the displacement of the valve core. The calculation formula is: ,in, For the moment The corresponding equivalent electromagnetic force waveform; For the moment The coil current value; is the coil inductance Displacement The first derivative of is obtained by fitting the measured inductance function; is the valve core displacement position;

[0068] S22: Based on the acquired valve core displacement signal, the first-order and second-order derivative calculation methods are used to obtain the velocity and acceleration trajectories respectively, and a complete velocity-acceleration time series is constructed; the corresponding calculation formula is: ; ,in, For the moment The valve core speed value; For the moment The valve core acceleration value; For the moment The valve core displacement value; is the time variable;

[0069] S23: Based on the collected outlet pressure pulsation signal, the pressure change rate is obtained using the time-order derivative method, and then a pressure gradient curve reflecting the fluid disturbance process caused by the valve core action is constructed; the corresponding calculation formula is: ,in, For the moment The pressure gradient value; For the moment Outlet pressure pulsation signal value; is the time variable.

[0070] S3 specifically includes:

[0071] S31: Perform zero-crossing detection on the equivalent electromagnetic force waveform, intercept each zero-crossing segment, and calculate the asymmetric amplitude difference between the positive and negative half-cycles of the waveform to obtain the electromagnetic force zero-crossing distortion rate;

[0072] S32: Locate the velocity extreme value in the velocity-acceleration trajectory, monitor the instantaneous reversal of the acceleration direction before and after the extreme value, and calibrate the position that meets the valve core movement emergency stop-reverse characteristic as the inertia mutation point;

[0073] S33: Perform main peak and attenuation peak detection on the pressure gradient curve, extract the amplitude and time interval of each peak, and obtain the oscillation attenuation coefficient reflecting the fluid disturbance attenuation ability by fitting its decreasing trend; the above steps can characterize the mechanical anomalies, structural hysteresis and fluid instability behavior of the solenoid valve during the driving process from multiple angles by extracting three key features: zero-crossing distortion rate, inertia mutation point and oscillation attenuation coefficient, thereby significantly enhancing the ability to judge operational hazards and response accuracy.

[0074] S31 specifically includes:

[0075] S311: Equivalent electromagnetic force waveform Perform first-order sign change detection, traverse the sign changes between adjacent sampling points, and when . If the waveform between two points is continuous, the point is determined to be a zero-crossing point. , and As the center, the number of fixed sampling points is extended forward and backward Construct a local zero-crossing segment to obtain the time domain interval is the time interval between two adjacent sampling points, For the Sampling time points;

[0076] S312: In each zero-crossing segment, separate the positive half-cycle segment and the negative half-cycle segment of the waveform, and calculate the maximum amplitude of the positive and negative parts in the segment respectively, and set them as and , and calculate the amplitude index of the zero-crossing section based on this , the formula is: ,in, is the maximum electromagnetic force value of the positive half cycle; is the minimum electromagnetic force value of the negative half cycle; It is an indicator of asymmetric amplitude difference between positive and negative half cycles;

[0077] S313: Normalize and average the amplitude difference indicators of all zero-crossing sections to calculate the electromagnetic force zero-crossing distortion rate , whose expression is: ,in, is the electromagnetic force zero-crossing distortion rate; is the total number of zero-crossing segments detected; For the The amplitude difference of the zero-crossing segments; Respectively The above steps construct a symmetrical zero-crossing segment and extract the amplitude characteristics of the positive and negative half-cycles, which can accurately evaluate the degree of distortion of the electromagnetic drive waveform near the zero point, thereby improving the monitoring capability of potential operating problems such as abnormal response of the electromagnetic coil and unbalanced energy release.

[0078] S32 specifically includes:

[0079] S321: In the velocity-acceleration trajectory, local velocity maxima or minima are identified based on the velocity value change trend at adjacent time points. Specifically, when the velocity value at a certain time point is higher than the velocity values ​​at the adjacent time points before and after it, or lower than the velocity values ​​at the adjacent time points before and after it, the time point is determined to be a velocity extreme point, and its time position is recorded as a candidate point for subsequent inertia catastrophe analysis.

[0080] S322: With the velocity extreme point as the center, a fixed time window is expanded before and after it, and acceleration data within the time window is extracted. If the acceleration values ​​before and after the velocity extreme point are respectively positive and negative, or respectively negative and positive, that is, the positive and negative signs of the acceleration change suddenly, it indicates that the valve core has a dynamic transition behavior from acceleration to deceleration or from deceleration to acceleration at this time point, indicating that it has the physical characteristics of emergency stop and reverse.

[0081] S323: Calculate the acceleration change rate of the symmetrical time positions before and after the velocity extreme point. If the acceleration change rate exceeds the preset mutation determination threshold, the velocity extreme point is marked as an inertia mutation point. The acceleration change rate calculation formula is: ,in, is the rate of change of acceleration; are the acceleration values ​​at the symmetrical time points before and after the velocity extreme point; The time span is half of the acceleration value range; is the time position of the velocity extreme point; the above steps can accurately calibrate the inertial mutation behavior of the valve core during operation by detecting local extreme points in the velocity trajectory and combining the mutation situation and mutation rate evaluation in the front and rear acceleration directions. It can effectively reflect the motion discontinuity problem caused by friction, blockage or electromagnetic drive imbalance, thereby providing a dynamic basis for the accurate identification of sticking characteristics.

[0082] S33 specifically includes:

[0083] S331: Analyze the sign change of the first-order derivative of the pressure gradient curve to identify the time point and amplitude of the main peak, and then detect each local maximum and its time position in ascending time order until the curve oscillation amplitude drops below the noise threshold, completing the peak sequence extraction;

[0084] S332: Calculate the amplitude ratio for each extracted attenuation peak With time interval , and Composed of attenuation feature point set; the calculation formula is as follows: ,in, For the The attenuation peak amplitude; is the main peak amplitude; For the The time when the attenuation peak occurs; is the main peak appearance time;

[0085] S333: Establishing an exponential decay model based on a decay feature point set , and the least square method is used to solve the attenuation coefficient, and then the oscillation attenuation coefficient reflecting the fluid disturbance attenuation ability is obtained , and its solution formula is: ,in, is the attenuation peak amplitude ratio; The main peak and the The time interval between the decay peaks; is the oscillation attenuation coefficient; The above steps are performed by exponentially fitting the amplitude ratio of the main peak and the attenuation peak of the pressure gradient curve to the time interval to obtain a single dimensionless coefficient , which can quantify the attenuation rate of fluid pressure disturbance after valve core action, and then accurately evaluate the damping characteristics of the outlet flow channel and the system stability, providing a highly sensitive criterion for the comprehensive judgment of stuck-instability coupling faults.

[0086] S4 specifically includes:

[0087] S41: Select a time point from the inertia mutation points extracted in S3 , and retrieve the most recent electromagnetic force zero-crossing time in its adjacent time window , calculate the time offset between the two , its calculation expression is: ;

[0088] S42: Set the theoretical response time window threshold , this threshold represents the maximum permissible time delay between the electromagnetic force zero crossing point and the valve core speed / acceleration response under normal driving conditions;

[0089] S43: For all To judge, when there is any set of offsets that meet When the valve core responds slowly to the driving signal and there is potential hysteresis in the system movement, a primary sticking warning signal is generated, and the corresponding time point and related characteristic data are recorded. The above steps calculate the actual time offset between the zero-crossing point of the electromagnetic driving force and the dynamic response of the valve core, and compare and distinguish it with the theoretical response time window. This can realize real-time monitoring of response hysteresis and sticking risk, help to timely discover nonlinear motion anomalies before faults occur, and improve the safety and predictive ability of solenoid valve operation.

[0090] S5 specifically includes:

[0091] S51: Perform fast Fourier transform on the equivalent electromagnetic force waveform obtained in S2 to obtain its frequency domain representation, extract the fundamental frequency component and several subsequent harmonic components, and calculate the harmonic distortion of the electromagnetic force waveform. , which is defined as the square root of the ratio of the sum of the squares of the higher-order harmonic amplitudes to the square of the fundamental amplitude, and the expression is: ,in, is the harmonic distortion of the electromagnetic force waveform; For the The amplitude of the harmonic components of order; is the amplitude of the fundamental component; The upper limit of the harmonic order extracted;

[0092] S52: The oscillation attenuation coefficient calculated in S3 and harmonic distortion Multiplying them together, we get the stability degradation index that characterizes the degree of nonlinear coupling between the electromagnetically modulated fluid response and the drive. , its calculation expression is: The above steps extract the non-ideal harmonic components in the electromagnetic force waveform through the frequency domain analysis method, and combine it with the attenuation ability of the fluid pressure disturbance to construct a stability degradation index, thereby achieving a quantitative characterization of the stability degradation trend of the electromagnetic-hydraulic coupling system, and providing a highly sensitive, multi-dimensional diagnostic basis for the comprehensive diagnosis of the risk of sticking and oscillation.

[0093] S6 specifically includes:

[0094] S61: Real-time monitoring of the primary jam warning result generated in S4. When a jam warning signal is triggered in any detection cycle, it is determined that there is a risk of drive-response delay.

[0095] S62: Simultaneously read the stability degradation index calculated in S5 and compare it with the dynamic threshold value set according to the current working conditions. Comparison, if both the primary jam warning has been triggered and the stability degradation index is greater than the dynamic threshold When these two conditions are met, the system outputs the stuck-instability coupled fault judgment conclusion and records the corresponding timestamp, valve core speed, acceleration, pressure gradient value and waveform distortion parameters of the fault as the basis for subsequent fault backtracking and operation and maintenance analysis;

[0096] The above dynamic threshold is determined based on the rated frequency, pressure stability level and drive power coefficient of the solenoid valve, and is adaptive to the working conditions. The calculation expression of the dynamic threshold is: ,in, is the rated operating frequency of the solenoid valve; is the system damping coefficient; Rated driving electromagnetic force of the solenoid valve; is the rated outlet working pressure; is the empirical adjustment coefficient, which is determined by experimental calibration and has the following value range:

[0097] , used to adapt to different frequency levels;

[0098] , used to reflect the degree of damping influence;

[0099] Used to reflect the influence of the drive / load ratio; by introducing a multi-factor dynamic adjustment mechanism, the stability degradation threshold can be adaptively set according to the actual operating parameters of the solenoid valve, avoiding false alarms due to setting too low and missing alarms due to setting too high, effectively ensuring the accuracy and practicality of fault identification.

[0100] The present invention encompasses any alternatives, modifications, equivalents, and solutions that fall within the spirit and scope of the present invention. To provide a thorough understanding of the present invention, specific details are described in detail below in connection with the preferred embodiments of the present invention, but those skilled in the art will be able to fully understand the present invention without these detailed descriptions. Furthermore, to avoid unnecessary confusion regarding the essence of the present invention, well-known methods, processes, procedures, components, and circuits have not been described in detail.

[0101] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A combined testing method for stability and sticking detection of a solenoid valve during operation, characterized in that: The following steps are involved: S1: During the solenoid valve driving stage, the coil current signal, valve core displacement signal and outlet pressure pulsation signal are synchronously collected; S2: Convert the current signal collected by S1 into an equivalent electromagnetic force waveform, the displacement signal into a velocity-acceleration trajectory, and the outlet pressure pulsation signal into a pressure gradient curve; S3: Based on the data converted by S2, the zero-crossing distortion rate of the electromagnetic force, the inertia mutation point of the velocity-acceleration trajectory, and the oscillation attenuation coefficient of the pressure gradient curve are extracted; S4: Calculate the time offset between the inertia mutation point in S3 and the electromagnetic force zero-crossing distortion rate. When the offset exceeds the theoretical response time window of the valve core movement, a primary jam warning is generated. S5: Multiply the oscillation attenuation coefficient in S3 by the harmonic distortion of the electromagnetic force waveform to obtain the stability degradation index; S6: When the primary stuck warning is triggered and the stability degradation index exceeds the dynamic threshold, the conclusion of the stuck-instability coupled fault is output.

2. A combined testing method for stability and sticking detection of a solenoid valve during operation according to claim 1, characterized in that: Said S1 specifically includes: S11: When the solenoid valve receives the driving command signal, the coil current in the driving circuit is sampled in real time through the current sensor, and the sampling result is output to the current channel of the data acquisition card; S12: A laser displacement sensor is arranged axially opposite to the center of the solenoid valve core to record the axial displacement of the valve core in real time during the driving process, and the displacement signal is synchronously transmitted to the displacement channel of the data acquisition card; S13: A piezoelectric pressure sensor is installed on the outlet pipe of the solenoid valve. The sensor sensitivity is not less than 10mV / kPa. It is used to sense the pressure fluctuation caused by the valve core movement in real time and transmit the outlet pressure pulsation signal in the form of analog voltage to the pressure channel of the data acquisition card; S14: The data acquisition card synchronously acquires three types of signals: current, displacement and pressure under a preset unified sampling clock.

3. A combined testing method for stability and sticking detection of a solenoid valve during operation according to claim 1, characterized in that: The S2 specifically includes: S21: Based on the coil current signal collected by S1 and the structural inductance model of the solenoid valve, the current signal is converted into the corresponding equivalent electromagnetic force waveform ; S22: Based on the acquired valve core displacement signal, the first-order and second-order derivative calculation methods are used to obtain the velocity and acceleration trajectories respectively, and a complete velocity-acceleration time series is constructed; S23: Based on the collected outlet pressure pulsation signal, a time-order derivative method is used to obtain the pressure change rate, and then a pressure gradient curve reflecting the fluid disturbance process caused by the valve core action is constructed.

4. A combined testing method for stability and sticking detection of a solenoid valve during operation according to claim 3, characterized in that: The S3 specifically includes: S31: Perform zero-crossing detection on the equivalent electromagnetic force waveform, intercept each zero-crossing segment, and calculate the asymmetric amplitude difference between the positive and negative half-cycles of the waveform to obtain the electromagnetic force zero-crossing distortion rate; S32: Locate the velocity extreme value in the velocity-acceleration trajectory, monitor the instantaneous reversal of the acceleration direction before and after the extreme value, and calibrate the position that meets the valve core movement emergency stop-reverse characteristic as the inertia mutation point; S33: Perform main peak and attenuation peak detection on the pressure gradient curve, extract the amplitude and time interval of each peak, and obtain the oscillation attenuation coefficient reflecting the fluid disturbance attenuation ability by fitting its decreasing trend.

5. A combined testing method for stability and sticking detection of a solenoid valve during operation according to claim 4, characterized in that: The S31 specifically includes: S311: Equivalent electromagnetic force waveform Perform first-order sign change detection, traverse the sign changes between adjacent sampling points, and when . If the waveform between two points is continuous, the point is determined to be a zero-crossing point. , and As the center, the number of fixed sampling points is extended forward and backward Construct a local zero-crossing segment to obtain a time domain interval; S312: In each zero-crossing segment, separate the positive half-cycle segment and the negative half-cycle segment of the waveform, and calculate the maximum amplitude of the positive and negative parts in the segment respectively, and set them as and , and calculate the amplitude index of the zero-crossing section based on this ; S313: Normalize and average the amplitude difference indicators of all zero-crossing sections to calculate the electromagnetic force zero-crossing distortion rate .

6. A combined testing method for stability and sticking detection of a solenoid valve during operation according to claim 4, characterized in that: The S32 specifically includes: S321: In the velocity-acceleration trajectory, based on the velocity value change trend of adjacent time points, identify the local velocity maximum or minimum. Specifically, when the velocity value at a certain time point is higher than the velocity values ​​of the adjacent time points before and after it, or lower than the velocity values ​​of the adjacent time points before and after it, the time point is determined to be a velocity extreme point. S322: With the velocity extreme point as the center, a fixed time window is expanded before and after it, and acceleration data within the time window is extracted; when the acceleration values ​​before and after the velocity extreme point are respectively positive and negative, or respectively negative and positive, the sign of the acceleration changes suddenly; S323: Calculate the acceleration change rate of the symmetrical time positions before and after the velocity extreme point. If the acceleration change rate exceeds a preset mutation determination threshold, mark the velocity extreme point as an inertia mutation point.

7. A combined testing method for stability and sticking detection of a solenoid valve during operation according to claim 4, characterized in that: The S33 specifically includes: S331: Analyze the sign change of the first-order derivative of the pressure gradient curve to identify the time point and amplitude of the main peak, and then detect each local maximum and its time position in ascending time order until the curve oscillation amplitude drops below the noise threshold, completing the peak sequence extraction; S332: Calculate the amplitude ratio for each extracted attenuation peak With time interval , and Composition of attenuation feature point set; S333: Establishing an exponential decay model based on a decay feature point set , and the least square method is used to solve the attenuation coefficient, and then the oscillation attenuation coefficient reflecting the fluid disturbance attenuation ability is obtained .

8. A combined testing method for stability and sticking detection of a solenoid valve during operation according to claim 1, characterized in that: The S4 specifically includes: S41: Select a time point from the inertia mutation points extracted in S3 , and retrieve the most recent electromagnetic force zero-crossing time in its adjacent time window , calculate the time offset between the two ; S42: Set the theoretical response time window threshold ; S43: For all To judge, when there is any set of offsets that meet When the valve core is considered to be slow to respond to the drive signal, a primary sticking warning signal is generated.

9. A combined testing method for stability and sticking detection of a solenoid valve during operation according to claim 7, characterized in that: The S5 specifically includes: S51: Perform fast Fourier transform on the equivalent electromagnetic force waveform obtained in S2 to obtain its frequency domain representation, extract the fundamental frequency component and several subsequent harmonic components, and calculate the harmonic distortion of the electromagnetic force waveform. ; S52: The oscillation attenuation coefficient calculated in S3 and harmonic distortion Multiplying them together, we get the stability degradation index that characterizes the degree of nonlinear coupling between the electromagnetically modulated fluid response and the drive. .

10. A combined testing method for stability and sticking detection of a solenoid valve during operation according to claim 1, characterized in that: The S6 specifically includes: S61: Real-time monitoring of the primary jam warning result generated in S4. When a jam warning signal is triggered in any detection cycle, it is determined that there is a risk of drive-response delay. S62: Simultaneously read the stability degradation index calculated in S5 and compare it with the dynamic threshold value set according to the current working conditions. Comparison, if both the primary jam warning has been triggered and the stability degradation index is greater than the dynamic threshold When these two conditions are met, the output is a stuck-instability coupled fault judgment conclusion.

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