Method and device for monitoring health state of hydraulic plunger pump in real time

Abstract

The invention provides a real-time monitoring method and device for the health state of a hydraulic plunger pump, and belongs to the field of aviation hydraulic pressure. The method comprises the steps that a first relation between the total leakage rate of the hydraulic plunger pump and operating parameters of the electro-hydrostatic actuator is determined, and follow-up parameters are screened according to the dynamic change characteristics of the operating parameters along with the working condition and the health state of the hydraulic plunger pump; the first relation of the total leakage amount of the plunger pump is adjusted based on the follow-up parameters, and a second relation is obtained; according to the second relation, the plunger pump torque is calculated by combining the energy conservation law; a plunger pump torque calculation formula is optimized based on the incidence relation of the viscous friction torque, the coulomb friction torque and the follow-up parameters; and real-time operation parameters of the plunger pump are monitored, a first coefficient and a second coefficient are calculated based on the real-time operation parameters, the first coefficient and the second coefficient are input into the neural network to construct a state monitoring model, and the operation state of the plunger pump is evaluated. According to the method and the device, the running state of the hydraulic plunger pump can be monitored in real time.

Description

Technical Field

[0001] The present application relates to the field of aviation hydraulic technology, and in particular to a method and device for real-time monitoring of the health status of a hydraulic plunger pump. Background Art

[0002] With the rapid development of aviation technology, the reliability and safety requirements of aircraft electromechanical systems are increasing. As a key component of the aircraft hydraulic system, the performance of the electrostatic hydraulic actuator directly affects the flight safety of the aircraft. The aviation hydraulic piston pump is the core power component of the electrostatic hydraulic actuator. However, in the actual operation process, due to factors such as harsh working environment and frequent load changes, the aviation hydraulic piston pump is prone to failure, which seriously affects the normal operation of the electrostatic hydraulic actuator. Therefore, real-time monitoring of the health status of the aviation hydraulic piston pump is of great significance to ensure the safe flight of the aircraft.

[0003] Most of the existing methods for monitoring the health status of hydraulic piston pumps are aimed at traditional hydraulic systems and cannot meet the special requirements of electrostatic hydraulic actuators. Electrostatic hydraulic actuators use closed hydraulic oil circuits, high motor speeds, short single-running time, and frequent start-stop and reversing, which makes the working conditions of aviation hydraulic piston pumps more complicated. In addition, there are fewer internal sensors in electrostatic hydraulic actuators. At present, there is a lack of effective methods for monitoring the health status of aviation hydraulic piston pumps for electrostatic hydraulic actuators, and it is impossible to use the working status data of electrostatic hydraulic actuators to realize real-time monitoring of the operating status of hydraulic piston pumps. Summary of the invention

[0004] In view of this, the present application provides a method and device for real-time monitoring of the health status of a hydraulic plunger pump, which can realize real-time monitoring of the operating status of the hydraulic plunger pump.

[0005] Specifically, the present application is implemented through the following technical solutions:

[0006] The first aspect of the present application provides a method for real-time monitoring of the health status of a hydraulic plunger pump, the method comprising:

[0007] Determine a first relationship between the total leakage of the hydraulic piston pump and the operating parameters of the electrostatic hydraulic actuator, and select the follow-up parameters according to the dynamic change characteristics of the operating parameters with the working condition and health state of the hydraulic piston pump;

[0008] Adjusting the first relationship of the total leakage of the plunger pump based on the follow-up parameter to obtain a second relationship;

[0009] According to the second relationship, the plunger pump torque is calculated in combination with the law of conservation of energy; the torque at least includes viscous friction torque and Coulomb friction torque;

[0010] Based on the correlation between the viscous friction torque, the Coulomb friction torque and the follow-up parameter, the plunger pump torque calculation formula is optimized; wherein the optimized plunger pump torque calculation formula includes a first coefficient and a second coefficient, and the first coefficient and the second coefficient are dynamic fitting coefficients, which are dynamically adjusted as the health status of the plunger pump changes;

[0011] Monitor the real-time operating parameters of the plunger pump, calculate the first coefficient and the second coefficient based on the real-time operating parameters, and input the first coefficient and the second coefficient into a neural network to construct a state monitoring model to evaluate the operating state of the plunger pump.

[0012] A second aspect of the present application provides a real-time monitoring device for the health status of a hydraulic plunger pump, the device comprising a screening module, an adjustment module, a calculation module, an optimization module and a monitoring module;

[0013] The screening module is used to determine a first relationship between the total leakage of the hydraulic piston pump and the operating parameters of the electrostatic hydraulic actuator, and screen the follow-up parameters according to the dynamic change characteristics of the operating parameters with the working condition and health state of the hydraulic piston pump;

[0014] The adjustment module is used to adjust the first relationship of the total leakage of the plunger pump based on the follow-up parameter to obtain a second relationship;

[0015] The calculation module is used to calculate the plunger pump torque according to the second relationship in combination with the law of conservation of energy; the torque at least includes viscous friction torque and Coulomb friction torque;

[0016] The optimization module is used to optimize the plunger pump torque calculation formula based on the correlation between the viscous friction torque, the Coulomb friction torque and the follow-up parameter; wherein the optimized plunger pump torque calculation formula includes a first coefficient and a second coefficient, and the first coefficient and the second coefficient are dynamic fitting coefficients, which are dynamically adjusted as the health state of the plunger pump changes;

[0017] The monitoring module is used to monitor the real-time operating parameters of the plunger pump, calculate the first coefficient and the second coefficient based on the real-time operating parameters, and input the first coefficient and the second coefficient into a neural network to construct a state monitoring model to evaluate the operating state of the plunger pump.

[0018] The real-time monitoring method and device for the health status of a hydraulic piston pump provided by the present application, in combination with the law of conservation of energy and the relationship between the operating parameters of the electrostatic hydraulic actuator, establishes a plunger pump torque calculation formula, wherein torque is one of the important indicators reflecting the working status of the hydraulic piston pump. By accurately calculating the torque, the internal stress of the hydraulic piston pump can be deeply understood, and its health status can be evaluated. By analyzing the correlation between the viscous friction torque, the Coulomb friction torque and the follow-up parameters, the plunger pump torque calculation formula is optimized, and a formula containing dynamic fitting coefficients is obtained. These coefficients are dynamically adjusted as the health status of the piston pump changes, so that the torque calculation is more accurate and can more sensitively reflect the health status changes of the hydraulic piston pump. It can be seen that the present invention first locates the parameters related to the health status in the total leakage through the screening of the follow-up parameters, that is, finds the associated variables of the health status parameters, and then starts from the associated variables to find the relationship between the associated variables and the operating parameters of the hydraulic piston pump, and then can directly use the operating parameters to determine the corresponding health status, simplifying the process of state evaluation, and the present invention combines the working conditions and structural characteristics of the electrostatic hydraulic actuator, avoiding the situation of adding additional sensors, and reducing costs. By using a neural network to construct a state monitoring model, the current operating state of the hydraulic piston pump can be monitored in real time by inputting the first coefficient and the second coefficient, providing strong support for fault diagnosis and prediction. The method provided in this application can comprehensively and accurately monitor the health state of the aviation hydraulic piston pump for the electrostatic hydraulic actuator, adapt to changes in complex working conditions, and ensure the reliable operation of the electrostatic hydraulic actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A flow chart of a first embodiment of a method for real-time monitoring of the health status of a hydraulic plunger pump provided in the present application;

[0020] Figure 2 A control flow chart for monitoring the real-time operating parameters of a plunger pump shown in this application;

[0021] Figure 3 This is a structural schematic diagram of Example 2 of the real-time monitoring device for the health status of a hydraulic plunger pump provided in this application. DETAILED DESCRIPTION

[0022] Here, exemplary embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application.

[0023] The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in this article refers to and includes any or all possible combinations of one or more associated listed items.

[0024] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0025] Specific embodiments are given below to introduce the technical solution of the present application in detail.

[0026] Figure 1 This is a flow chart of the first embodiment of the method for real-time monitoring of the health status of a hydraulic piston pump provided in this application. Figure 1 , the method provided in this embodiment may include:

[0027] S101, determining a first relationship between a total leakage of a hydraulic piston pump and an operating parameter of an electrostatic hydraulic actuator, and selecting a follow-up parameter according to a dynamic change characteristic of the operating parameter with a working condition and a health state of the hydraulic piston pump.

[0028] It should be noted that the first relationship between the total leakage of the hydraulic piston pump and the operating parameters of the electrostatic hydraulic actuator is determined, and the follow-up parameters are screened according to the dynamic change characteristics of the operating parameters with the working condition and health status of the hydraulic piston pump, including:

[0029] (1) Calculate the total leakage of the electrostatic hydraulic actuator.

[0030] It should be noted that the total leakage is one of the important indicators reflecting the working state of the electrostatic hydraulic actuator, and its size directly affects the performance and efficiency of the system. Calculating the total leakage can provide basic data for subsequent analysis of the cause of the leakage and evaluation of the health status of the system. Among them, the total leakage can be approximately calculated by measuring the amount of oil replenished in the hydraulic system within a certain period of time, or by using a pressure sensor and a flow sensor, the total leakage can be calculated based on the relationship between the system pressure change and the flow change. Specifically, a suitable method can be selected for calculation according to actual needs, and it is not limited in this embodiment.

[0031] (2) Determining an operating parameter of the electrostatic hydraulic actuator associated with the total leakage.

[0032] It should be noted that the operating parameters closely related to the total leakage are found out. The changes of these parameters will directly or indirectly affect the total leakage, thus providing a basis for analyzing and controlling the leakage. For example, the operating parameters can be the motor current signal of the electrostatic hydraulic actuator, the displacement signal of the actuator cylinder, and the speed signal of the encoder. This is because these signals can reflect the working status of the electrostatic hydraulic actuator and the hydraulic piston pump therein from different angles.

[0033] Among them, the motor is the power source that drives the hydraulic piston pump. The size and change of the motor current can indirectly reflect the load condition, working efficiency and whether there is abnormal resistance of the hydraulic piston pump. For example, when a fault occurs inside the hydraulic piston pump, resulting in increased friction or abnormal load, the motor current may change accordingly. The displacement of the actuator is closely related to the output flow and pressure of the hydraulic piston pump. By monitoring the displacement signal of the actuator, the working stroke and output performance of the hydraulic piston pump can be understood, and then it can be determined whether it is working normally. The encoder can accurately measure the speed of the motor, and the motor speed directly affects the speed of the hydraulic piston pump. The speed of the hydraulic piston pump has an important influence on its performance and working stability. Therefore, the speed signal is also one of the important bases for evaluating the health status of the hydraulic piston pump.

[0034] (3) Obtaining the correlation between the operating parameters and the structural parameters of the hydraulic piston pump, and determining the fixed parameters.

[0035] It should be noted that fixed parameters are determined by the design of the structural properties of the plunger pump, which may include structural dimensions, geometric relationships of moving parts, component connections and matching methods, and material properties, etc., and their numerical values ​​remain basically unchanged during the normal operation of the plunger pump. For example, structural parameters such as the plunger diameter, plunger distribution circle radius, and swash plate inclination of the plunger pump are fixed parameters. These parameters mainly affect the basic performance and working range of the hydraulic plunger pump, and can be used as reference values ​​during the monitoring process to determine whether the changes in other parameters are normal.

[0036] (4) Obtaining the dynamic change characteristics of the operating parameters related to the operating state and health level of the hydraulic piston pump, and determining the follow-up parameters.

[0037] It should be noted that the purpose of analyzing the collected operating parameters and identifying the dynamic change characteristics related to the operating status of the hydraulic piston pump according to the preset algorithm is to extract the most valuable information for monitoring the health status of the hydraulic piston pump. These algorithms can be based on signal processing technology, machine learning algorithms or methods in other related fields. For example, a spectrum analysis algorithm can be used to analyze the frequency components of the motor current signal to detect whether there are abnormal frequency components, which may be related to the failure mode of the hydraulic piston pump. For another example, a wavelet transform algorithm can be used to process the displacement signal of the actuator to extract the mutation points and characteristic waveforms in the signal, so as to determine whether the working state of the hydraulic piston pump has changed.

[0038] Among them, dynamic characteristic changes refer to signal characteristics that change significantly with time or working conditions during the operation of the hydraulic piston pump. For example, the amplitude fluctuation and frequency change of the motor current signal, the speed change and acceleration change of the actuator displacement signal, and the fluctuation amplitude of the encoder speed signal.

[0039] Specifically, the follow-up parameters are determined according to the changes in dynamic characteristics, wherein the follow-up parameters change with the changes in the working environment and / or health status of the piston pump, and they can directly reflect the actual working state and performance changes of the hydraulic piston pump. For example, parameters such as leakage, friction coefficient, and volumetric efficiency are follow-up parameters. Changes in leakage will affect the output flow and pressure of the hydraulic piston pump, changes in friction coefficient will lead to energy loss and reduced efficiency, and changes in volumetric efficiency reflect the degree of internal leakage and wear of the hydraulic piston pump. By monitoring the changes in the follow-up parameters, potential faults of the hydraulic piston pump can be discovered in a timely manner, and the degree of deterioration of its health status can be evaluated. S102. The first relationship of the total leakage of the piston pump is adjusted based on the follow-up parameters to obtain a second relationship.

[0040] It should be noted that the second relationship is obtained by adjusting the first relationship of the total leakage of the plunger pump based on the following parameter, including:

[0041] (1) Determining a first relationship of a total leakage of a piston pump; the first relationship includes a relationship between the total leakage and a fixed parameter and a follower parameter of an electrostatic hydraulic actuator.

[0042] It should be noted that the first relationship of the total leakage of the plunger pump is a mathematical expression describing the total leakage and related parameters. Specifically, the first relationship of the total leakage of the plunger pump is as follows:

[0043] ;

[0044] in, is the gap leakage flow of the sliding shoe pair, is the gap leakage flow of the plunger ball joint pair, is the gap leakage flow of the plunger pair, It is the gap leakage flow of the distribution pair.

[0045] In the actual operation of the plunger pump, as a high-speed and high-pressure rotary hydraulic machine, the internal parts of the plunger pump will be damaged and degraded due to long-term friction and wear and pressure alternating loads, which will cause certain performance degradation of the plunger pump. In the above formula, all parameters related to the leakage of the plunger pump can be divided into fixed parameters and follow-up parameters.

[0046] (2) Extracting a follow-up parameter from the first relationship, and adjusting the first relationship of the total leakage of the plunger pump based on the follow-up parameter to obtain a second relationship.

[0047] It should be noted that the purpose of extracting the follow-up parameters from the first relationship is to clarify which parameters change dynamically with the working state of the plunger pump, and these parameters have a more significant impact on the total leakage.

[0048] The second relationship is obtained by adjusting the first relationship of the total leakage of the plunger pump based on the following parameter in order to more accurately reflect the changes in the total leakage in actual work. Since the following parameter will change with time and working conditions, by incorporating it into the relationship of the total leakage for adjustment, the obtained second relationship can be made more consistent with the actual working conditions, thereby improving the accuracy of monitoring the health status of the plunger pump.

[0049] Specifically, the second relationship of the total leakage of the plunger pump is as follows:

[0050] ;

[0051] in, is the eccentricity, is the outlet oil pressure, is the oil return pressure, is the total leakage coefficient of all friction pairs of the hydraulic piston pump, They are the oil film clearance of the sliding shoe and inclined plate friction pair, the oil film clearance of the plunger sliding shoe ball joint pair, the clearance between the plunger and the plunger hole of the cylinder body, and the oil film clearance of the friction pair of the cylinder body distribution plate.

[0052] It should be noted that in the first relationship of the total leakage of the plunger pump, we quantitatively define the first relationship of the total leakage of the plunger pump as the sum of the leakage of each important friction pair in the hydraulic plunger pump. In actual operation, the damage and degradation of internal components due to wear cannot be directly obtained from the first relationship. At the same time, the leakage of the above four friction pairs is a nonlinear expression of the above four clearance values, that is, the size of the leakage is closely related to the clearance value. Therefore, we adjust the total leakage flow to a combination of fixed parameters and variable parameters to facilitate monitoring of changes in the leakage of the hydraulic plunger pump.

[0053] S103. Calculate the plunger pump torque according to the second relationship and in combination with the law of conservation of energy; the torque at least includes viscous friction torque and Coulomb friction torque.

[0054] It should be noted that, according to the second relationship, combined with the law of conservation of energy, the plunger pump torque is calculated, including:

[0055] (1) According to the law of conservation of energy, the energy balance equation of the plunger pump during operation is established.

[0056] It should be noted that according to the law of conservation of energy:

[0057] ;

[0058] in, is the output power, is the input power, is the torque loss, For flow loss.

[0059] It should also be noted that volumetric efficiency is an important indicator to characterize the output performance of hydraulic piston pumps, and its expression can generally be expressed as:

[0060] ;

[0061] in, is the input flow, is the output flow, is the instantaneous flow rate, is the total leakage flow.

[0062] Among them, for a certain hydraulic piston pump, the piston diameter can be calculated based on the structural parameter , plunger distribution circle radius , Inclination angle , to obtain the instantaneous theoretical flow rate:

[0063] ;

[0064] in, is the angular velocity of the piston pump, is the number of plungers in the plunger pump.

[0065] By combining the law of conservation of energy and volumetric efficiency, the law of conservation of energy can be transformed into the form of a power balance expression to obtain the energy balance equation, as follows:

[0066] ;

[0067] in, For other traffic losses, is the damping torque related to the viscosity of the hydraulic oil, is the friction torque associated with the moving parts of the piston pump, is the outlet oil pressure, For imported oil pressure, It is the return oil pressure. For the introduction of other parameters, please refer to the above description.

[0068] like , then the above formula can be simplified to get:

[0069] ;

[0070] in, .

[0071] (2) Substitute the second relational expression of the total leakage into the energy balance equation to obtain the plunger pump torque calculation formula.

[0072] It should be noted that the second relationship of the total leakage is obtained on the basis of considering the influence of the follow-up parameters on the leakage, which more accurately describes the leakage of the plunger pump in actual work. Substituting the second relationship expression of the total leakage into the energy balance equation, the relationship between the leakage and other parameters can be further analyzed, thereby deriving the calculation formula of the plunger pump torque.

[0073] Specifically, by organizing and deriving the energy balance equation, the torque can be expressed as a function of leakage, pressure, speed and other related parameters. In this process, the viscous friction torque and Coulomb friction torque, as part of the energy loss, will be included in the torque calculation formula.

[0074] Specifically, the plunger pump torque calculation formula is as follows:

[0075] ;

[0076] The first half of the right side of the equal sign is defined as the equivalent torque of hydraulic pressure, where the friction torque is It can be divided into viscous friction torque and Coulomb friction torque For the meaning of other related parameters, please refer to the above introduction and will not be repeated here.

[0077] S104. Optimize the plunger pump torque calculation formula based on the correlation between the viscous friction torque, the Coulomb friction torque and the follow-up parameter; wherein the optimized plunger pump torque calculation formula includes a first coefficient and a second coefficient, and the first coefficient and the second coefficient are dynamic fitting coefficients, which are dynamically adjusted as the health status of the plunger pump changes.

[0078] It should be noted that, based on the correlation between the viscous friction torque, the Coulomb friction torque and the follow-up parameter, the plunger pump torque calculation formula is optimized, including:

[0079] (1) Analyze the relationship between the viscous friction torque, Coulomb friction torque and follow-up parameters under various piston pump states.

[0080] It should be noted that the viscous friction torque is mainly related to the viscosity of the oil and the relative movement speed of the moving parts inside the plunger pump. The oil viscosity in the follow-up parameter will change with the changes in working conditions such as temperature and pressure, which will directly affect the size of the viscous friction torque. The Coulomb friction torque is related to the normal pressure between the friction pairs and the friction coefficient. The load change in the follow-up parameter will cause the normal pressure between the friction pairs to change, thereby affecting the Coulomb friction torque.

[0081] It should be noted that when monitoring the state of the plunger pump, we only need to pay attention to the quantity that changes with the state of the plunger pump. Therefore, for the viscous friction torque , its expression can be written as:

[0082] ;

[0083] in, is the hydraulic viscosity, is the total friction torque of viscous friction, is the angular velocity of the hydraulic piston pump. For the meaning of other related parameters, please refer to the above introduction.

[0084] Similarly, for the Coulomb friction torque , its expression can be written as:

[0085] ;

[0086] in, is the workload pressure, is the total friction torque of Coulomb friction related to the pressure difference, is the Coulomb friction coefficient of the distribution pair under the static pressure support, is the Coulomb friction coefficient of the sliding shoe pair under hydrostatic support, is the total friction torque of Coulomb friction related to the hydraulic piston pump structure, is the friction coefficient between the plunger and the piston cavity wall of the cylinder body, is the angular velocity of the hydraulic piston pump, is the plunger phase angle.

[0087] (2) The plunger pump torque calculation formula is adjusted according to the analysis results to obtain an optimized formula including the first coefficient and the second coefficient.

[0088] It should be noted that, according to the above analysis results, the plunger pump torque calculation formula is adjusted. On the basis of the original formula, the first coefficient and the second coefficient are introduced to respectively reflect the relationship between the viscous friction torque and the Coulomb friction torque and the follow-up parameters. Among them, the first coefficient can be a function related to the oil viscosity, speed, etc., which is dynamically adjusted as these follow-up parameters change, so as to accurately reflect the influence of the viscous friction torque on the plunger pump torque. The second coefficient can be a function related to the load, friction coefficient, etc., which will also be dynamically adjusted according to the changes in the follow-up parameters to reflect the influence of the Coulomb friction torque on the plunger pump torque.

[0089] Through such optimization, the torque calculation formula including the first coefficient and the second coefficient can more accurately describe the torque change of the plunger pump under different working conditions. When the health status of the plunger pump changes, such as wear, leakage and other problems, the follow-up parameters will change accordingly, which will cause the first coefficient and the second coefficient to change. By monitoring the dynamic adjustment of these coefficients, the health problems of the plunger pump can be discovered in time, improving the accuracy and reliability of monitoring.

[0090] Specifically, the adjusted plunger pump torque calculation formula is as follows:

[0091] ;

[0092] The meaning of each parameter is as described above and will not be repeated here.

[0093] Let the first coefficient , the second coefficient , then the optimization formula including the first coefficient and the second coefficient can be obtained:

[0094] ;

[0095] From the above formula, we can see that if and Keep constant, the input torque T and load pressure is linearly related, where and All about angular velocity For the meaning of other related parameters, please refer to the above introduction.

[0096] S105, monitoring the real-time operating parameters of the plunger pump, calculating the first coefficient and the second coefficient based on the real-time operating parameters, and inputting the first coefficient and the second coefficient into a neural network to construct a state monitoring model to evaluate the operating state of the plunger pump.

[0097] Combined with the optimization formula, it can be seen that in order to monitor the state of the plunger pump, it is only necessary to measure the input torque value under the current load condition to obtain the parameter and These two parameters directly represent the health status of the hydraulic piston pump. Therefore, in order to monitor the health status of the piston pump, it is also necessary to extract the input torque T and input speed , the inlet oil pressure of the plunger pump and outlet oil pressure .

[0098] Figure 2 For the control flow chart of monitoring the real-time operating parameters of the plunger pump shown in this application, please refer to Figure 2 Specifically, the real-time operating parameters of the monitoring piston pump include: detecting the displacement signal of the actuator cylinder; calculating the derivative value of the displacement signal and time; calculating the flow rate of the piston pump based on the product of the derivative value and the actuating area of ​​the actuator cylinder; and calculating the inlet oil pressure and outlet oil pressure of the piston pump according to the flow rate. It should be noted that the displacement signal of the actuator cylinder is one of the important bases for reflecting the working state of the hydraulic piston pump. By real-time monitoring of the displacement signal, the output of the piston pump can be indirectly obtained. In specific implementation, a displacement sensor can be used to detect the displacement signal of the actuator cylinder. The derivative value of the displacement signal and time is the speed signal of the actuator cylinder. Speed ​​is an important parameter to describe the motion state of an object. For a hydraulic piston pump, the speed of the actuator cylinder is directly related to the flow output of the pump. Calculating the speed signal can further analyze the working performance of the pump. Combined with the above description, the flow rate of the piston pump is calculated based on the product of the derivative value and the actuating area of ​​the actuator cylinder, which can be expressed as follows:

[0099] ;

[0100] in, is the actuating area of ​​the actuator, is the displacement speed.

[0101] Furthermore, according to the basic principles and relevant formulas of the hydraulic system, combined with the flow rate of the plunger pump and other parameters of the system, the inlet oil pressure and outlet oil pressure of the plunger pump can be calculated.

[0102] It should also be noted that monitoring the real-time operating parameters of the plunger pump includes: calculating the output torque of the servo motor based on the excitation current; determining the input torque of the hydraulic plunger pump based on the output torque of the servo motor, wherein the servo motor and the main shaft of the hydraulic plunger pump are directly connected via a spline.

[0103] There is a certain relationship between the motor output torque and the excitation current. Based on this relationship, the motor output torque can be calculated according to the excitation current after the excitation current is measured. The motor is directly connected to the plunger pump, and the output torque of the motor will be transmitted to the plunger pump. Therefore, the torque of the plunger pump can be indirectly obtained by measuring the motor input signal. Among them, a common method is to use the current and voltage sensors in the motor drive circuit to measure the input current and input voltage of the motor, and then calculate the torque of the plunger pump according to the power balance equation of the motor. Specifically, the speed and torque of the plunger pump can be obtained through the motor input signal, and the motor speed can be directly read by the encoder, where the motor output torque is:

[0104] ;

[0105] in, is a constant value, is the excitation current on the q-axis.

[0106] In specific implementation, in the electrostatic hydraulic actuator, the servo motor and the main shaft of the hydraulic piston pump are directly connected through a spline, so it can be considered that the input torque of the hydraulic piston pump is equal to the output torque of the servo motor, and the output torque of the servo motor can be directly obtained through the excitation current.

[0107] In addition, monitoring the real-time operating parameters of the plunger pump also includes: obtaining the speed information of the servo motor based on the sensor; determining the output speed of the servo motor based on the speed information of the servo motor; and calculating the input speed of the hydraulic plunger pump based on the output speed of the servo motor, wherein the servo motor and the hydraulic plunger pump in the electrostatic hydraulic actuator are rigidly connected through a spline.

[0108] Specifically, the servo motor and the hydraulic piston pump in the electrostatic hydraulic actuator are rigidly connected through a spline, and the input speed of the hydraulic piston pump depends on the output speed of the servo motor, and the speed of the servo motor can be directly read by a resolver sensor.

[0109] Furthermore, based on the obtained parameters such as input torque, input speed, inlet oil pressure and outlet oil pressure, and the optimized plunger pump torque calculation formula (including the first coefficient and the second coefficient), a set of equations can be established. By solving the set of equations, the values ​​of the first coefficient and the second coefficient in the current state can be calculated.

[0110] In addition, it should be noted that the evaluation of the operating status of the plunger pump includes:

[0111] (1) The principal component analysis method is used to reduce the dimension of the feature matrix of the current signal of the driving motor of the electrostatic hydraulic actuator in normal operation, the displacement signal of the actuator cylinder, and the speed signal of the encoder.

[0112] It should be noted that the principal component analysis method is used to reduce the dimension of the feature matrix of the current signal of the normal operation state of the driving motor of the electrostatic hydraulic actuator, the displacement signal of the actuator cylinder and the speed signal of the encoder. In the actual monitoring process, the acquired signal data often contains a large amount of feature information, some of which may be correlated or redundant. The principal component analysis method can project these high-dimensional feature data into a low-dimensional space and extract the main feature components, thereby reducing the dimension of the data and improving the efficiency of subsequent data analysis and processing.

[0113] (2) Determine the characteristic vector related to the operating state of the plunger pump based on the optimized torque calculation formula.

[0114] According to the optimized torque calculation formula, the eigenvectors related to the operating status of the plunger pump are determined. These eigenvectors are key feature combinations that can reflect the health status of the plunger pump. By analyzing the torque calculation formula, we can find out which parameters have a greater impact on the torque, and combine the features corresponding to these parameters to form a eigenvector. For example, if it is found that parameters such as inlet oil pressure, outlet oil pressure, and speed have an important impact on the calculation of torque and the operating status of the plunger pump, then the features corresponding to these parameters can be extracted to form a eigenvector, which can be used as the input of the subsequent state monitoring model.

[0115] (3) Building a state monitoring model based on the feature vector and long short-term memory neural network.

[0116] Long short-term memory neural network has good time series processing ability and can capture long-term dependencies in data. In the health status monitoring of plunger pumps, since its working process is a dynamic process and there is a certain correlation between the states at different times, long short-term memory neural network is very suitable for building a state monitoring model. By inputting the feature vector into the long short-term memory neural network for training, the model can learn the mapping relationship between the health status of the plunger pump and the feature vector. During the training process, a large amount of historical data is needed to optimize the model and adjust the parameters of the network to improve the accuracy and generalization ability of the model.

[0117] (4) Inputting the historical state operation data into the state monitoring model to obtain the state prediction result.

[0118] Input the historical state operation data into the built state monitoring model. The model will output the state prediction results of the plunger pump based on the input feature vector and the learned mapping relationship. These prediction results can reflect the health trend of the plunger pump in the future. For example, the model can predict whether the plunger pump has a failure risk, as well as the time and severity of the failure. By analyzing the state prediction results, corresponding maintenance measures can be taken in advance to avoid the occurrence of failures or reduce the losses caused by failures.

[0119] (5) Based on the residuals between the status monitoring results and the status prediction results, analyze the degree of deviation between the current status and the historical operating trend.

[0120] According to the residuals between the state monitoring results and the state prediction results, the degree of deviation between the current state and the historical operating trend is analyzed. The residual refers to the difference between the actual monitoring results and the predicted results. It reflects the prediction error of the model for the current state. By analyzing the size and change trend of the residual, it can be judged whether the current state is consistent with the historical operating trend. If the residual is small and stable, it means that the current state is consistent with the historical operating trend and the plunger pump is working normally; if the residual is large or shows an obvious change trend, it means that the current state may be abnormal and the cause needs to be further analyzed.

[0121] (6) Integrate prediction results and real-time monitoring data to evaluate the health status of the plunger pump.

[0122] Specifically, in practical applications, the health status of the plunger pump cannot be judged solely by the prediction results or real-time monitoring data, and the two need to be combined for comprehensive evaluation. For example, if the prediction results show that the plunger pump is at risk of failure, but the real-time monitoring data does not show obvious abnormalities, further observation and analysis are required at this time, and it may be necessary to increase the monitoring frequency or conduct more detailed tests. Conversely, if the real-time monitoring data shows that the plunger pump has an abnormality, but the prediction results do not indicate a fault, the prediction model also needs to be checked and optimized. By comprehensively considering the prediction results and real-time monitoring data, the health status of the plunger pump can be more accurately evaluated, potential problems can be discovered in a timely manner, and corresponding measures can be taken.

[0123] The method provided in this embodiment can comprehensively reflect the working state of the plunger pump by collecting multiple operating parameters such as motor current signal, actuator displacement signal and encoder speed signal, and screening out characteristic signals related to the operating state of the hydraulic plunger pump. By distinguishing between fixed parameters and follow-up parameters, it can better adapt to the complex and changeable working conditions of the electrostatic hydraulic actuator, and the introduction of follow-up parameters enables the monitoring method to capture the performance changes of the hydraulic plunger pump caused by the change of working conditions in real time, so as to more accurately evaluate its health status. In addition, combining the law of conservation of energy and the relationship between the relevant operating parameters of the electrostatic hydraulic actuator, a plunger pump torque calculation formula is established, wherein torque is one of the important indicators reflecting the working state of the hydraulic plunger pump. By accurately calculating the torque, the internal stress of the hydraulic plunger pump can be deeply understood, and then its health state can be evaluated. By analyzing the correlation between the viscous friction torque, the Coulomb friction torque and the follow-up parameters, the plunger pump torque calculation formula is optimized, and a formula containing dynamic fitting coefficients is obtained. These coefficients are dynamically adjusted as the health state of the plunger pump changes, making the torque calculation more accurate and able to more sensitively reflect the health changes of the hydraulic plunger pump. It should also be noted that the principal component analysis method is used to reduce the dimension of the signal feature matrix, which reduces the redundancy and complexity of the data. At the same time, the eigenvector related to the operating state of the plunger pump is determined according to the optimized torque calculation formula, which improves the efficiency of data processing and the accuracy of the model. The state monitoring model is built using a long short-term memory neural network, which can effectively process time series data and capture the changing trend of the health state of the plunger pump. By learning and training the historical state operation data, the model can accurately predict the current and future operating states, providing strong support for fault diagnosis and prediction.

[0124] Based on the energy conversion relationship, the present application derives the mapping relationship between the operating state parameters of the drive motor and the state parameters of the hydraulic plunger pump, and uses a mathematical model to analyze the change pattern of the plunger pump state parameters with the operating parameters of the drive motor and the actuator. Starting from the energy transfer relationship, it can solve the engineering problem of low reliability and difficulty in abnormal monitoring due to the small number of internal sensors in the electrostatic hydraulic actuator and the inability to directly monitor the health status of the hydraulic plunger pump.

[0125] Corresponding to the aforementioned embodiment of a method for real-time monitoring of the health status of a hydraulic plunger pump, the present application also provides an embodiment of a device for real-time monitoring of the health status of a hydraulic plunger pump.

[0126] Figure 3 This is a schematic diagram of the structure of the second embodiment of the real-time monitoring device for the health status of a hydraulic piston pump provided in this application. Figure 3 , the device provided in this embodiment includes a screening module 310, an adjustment module 320, a calculation module 330, an optimization module 340 and a monitoring module 350;

[0127] The screening module 310 is used to determine a first relationship between the total leakage of the hydraulic piston pump and the operating parameters of the electrostatic hydraulic actuator, and screen the follow-up parameters according to the dynamic change characteristics of the operating parameters with the working condition and health state of the hydraulic piston pump;

[0128] The adjustment module 320 is used to adjust the first relationship of the total leakage of the plunger pump based on the follow-up parameter to obtain a second relationship;

[0129] The calculation module 330 is used to calculate the plunger pump torque according to the second relationship in combination with the law of conservation of energy; the torque at least includes viscous friction torque and Coulomb friction torque;

[0130] The optimization module 340 is used to optimize the plunger pump torque calculation formula based on the correlation between the viscous friction torque, the Coulomb friction torque and the follow-up parameter; wherein the optimized plunger pump torque calculation formula includes a first coefficient and a second coefficient, and the first coefficient and the second coefficient are dynamic fitting coefficients, which are dynamically adjusted as the health state of the plunger pump changes;

[0131] The monitoring module 350 is used to monitor the real-time operating parameters of the plunger pump, calculate the first coefficient and the second coefficient based on the real-time operating parameters, and input the first coefficient and the second coefficient into a neural network to construct a state monitoring model to evaluate the operating state of the plunger pump.

[0132] The device of this embodiment can be used to perform Figure 1 The steps, specific implementation principles and implementation processes of the method embodiment shown are similar and will not be repeated here.

[0133] The implementation process of the functions and effects of each unit in the above-mentioned device is specifically described in the implementation process of the corresponding steps in the above-mentioned method, and will not be repeated here.

[0134] For the device embodiment, since it basically corresponds to the method embodiment, the relevant parts can refer to the partial description of the method embodiment. The device embodiment described above is only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present application scheme. A person of ordinary skill in the art can understand and implement it without paying any creative work.

[0135] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for real-time monitoring of the health status of a hydraulic piston pump, characterized in that: The method comprises: Determine a first relationship between the total leakage of the hydraulic piston pump and the operating parameters of the electrostatic hydraulic actuator, and select the follow-up parameters according to the dynamic change characteristics of the operating parameters with the working condition and health state of the hydraulic piston pump; Adjusting a first relationship of a total leakage of a plunger pump based on the follow-up parameter to obtain a second relationship; According to the second relationship, the plunger pump torque is calculated in combination with the law of conservation of energy; the torque at least includes viscous friction torque and Coulomb friction torque; Based on the correlation between the viscous friction torque, the Coulomb friction torque and the follow-up parameter, the plunger pump torque calculation formula is optimized; wherein the optimized plunger pump torque calculation formula includes a first coefficient and a second coefficient, and the first coefficient and the second coefficient are dynamic fitting coefficients, which are dynamically adjusted as the health status of the plunger pump changes; Monitor the real-time operating parameters of the plunger pump, calculate the first coefficient and the second coefficient based on the real-time operating parameters, and input the first coefficient and the second coefficient into a neural network to construct a state monitoring model to evaluate the operating state of the plunger pump.

2. The method according to claim 1, characterized in that: The real-time operating parameters of the monitoring plunger pump include: Detecting the displacement signal of the actuator; Calculate the time derivative of the displacement signal; Calculating the flow rate of the plunger pump based on the product of the derivative value and the actuating area of ​​the actuator; The inlet oil pressure and the outlet oil pressure of the plunger pump are calculated according to the flow rate.

3. The method according to claim 1, characterized in that Monitoring of real-time operating parameters of piston pumps includes: Calculate the output torque of the servo motor based on the excitation current; The input torque of the hydraulic piston pump is determined according to the output torque of the servo motor, wherein the servo motor and the main shaft of the hydraulic piston pump are directly connected via a spline.

4. The method according to claim 1, characterized in that: Monitor real-time operating parameters of piston pumps, including: Obtain the speed information of the servo motor based on the sensor; Determining the output speed of the servo motor according to the speed information of the servo motor; The input speed of the hydraulic piston pump is calculated based on the output speed of the servo motor, wherein the servo motor and the hydraulic piston pump in the electrostatic hydraulic actuator are rigidly connected through a spline.

5. The method according to claim 1, characterized in that The determining of the first relationship between the total leakage of the hydraulic piston pump and the operating parameters of the electrostatic hydraulic actuator, and screening the follow-up parameters according to the dynamic change characteristics of the operating parameters with the working condition and health state of the hydraulic piston pump, includes: Calculating the total leakage of the electrostatic hydraulic actuator; determining an operating parameter of the electrostatic hydraulic actuator associated with the total leakage; Obtaining the correlation between the operating parameters and the structural parameters of the hydraulic piston pump, and determining the fixed parameters; The dynamic change characteristics of the operating parameters related to the operating state and health level of the hydraulic piston pump are obtained, and the follow-up parameters are determined.

6. The method according to claim 1, characterized in that The first relationship of adjusting the total leakage of the plunger pump based on the follow-up parameter to obtain the second relationship includes: Determine a first relationship of the total leakage of the plunger pump; the first relationship includes a relationship between the total leakage and a fixed parameter and a follower parameter of the electrostatic hydraulic actuator; A follow-up parameter is extracted from the first relationship, and the first relationship of the total leakage of the plunger pump is adjusted based on the follow-up parameter to obtain a second relationship.

7. The method according to claim 1, characterized in that The step of calculating the plunger pump torque according to the second relationship and in combination with the law of conservation of energy includes: According to the law of conservation of energy, the energy balance equation of the plunger pump during operation is established; Substitute the second relational expression of the total leakage into the energy balance equation to obtain the plunger pump torque calculation formula.

8. The method according to claim 1, characterized in that The optimization of the plunger pump torque calculation formula based on the correlation between the viscous friction torque, the Coulomb friction torque and the follow-up parameter includes: Analyze the relationship between viscous friction torque, Coulomb friction torque and follow-up parameters under various piston pump states; The plunger pump torque calculation formula is adjusted according to the analysis results to obtain an optimized formula including the first coefficient and the second coefficient.

9. The method according to claim 1, characterized in that: The step of evaluating the operating state of the plunger pump comprises: The principal component analysis method is used to reduce the dimension of the characteristic matrix of the current signal of the driving motor of the electrostatic hydraulic actuator in normal operation, the displacement signal of the actuator cylinder and the speed signal of the encoder. Determine the characteristic vector related to the operation state of the plunger pump according to the optimized torque calculation formula; Building a state monitoring model based on the feature vector and the long short-term memory neural network; Inputting historical state operation data into the state monitoring model to obtain state prediction results; Analyze the degree of deviation between the current state and the historical operating trend based on the residuals between the state monitoring results and the state prediction results; Combine prediction results and real-time monitoring data to assess the health status of the plunger pump.

10. A real-time monitoring device for the health status of a hydraulic piston pump, characterized in that: The device includes a screening module, an adjustment module, a calculation module, an optimization module and a monitoring module; The screening module is used to determine a first relationship between the total leakage of the hydraulic piston pump and the operating parameters of the electrostatic hydraulic actuator, and screen the follow-up parameters according to the dynamic change characteristics of the operating parameters with the working condition and health state of the hydraulic piston pump; The adjustment module is used to adjust the first relationship of the total leakage of the plunger pump based on the follow-up parameter to obtain a second relationship; The calculation module is used to calculate the plunger pump torque according to the second relationship in combination with the law of conservation of energy; the torque at least includes viscous friction torque and Coulomb friction torque; The optimization module is used to optimize the plunger pump torque calculation formula based on the correlation between the viscous friction torque, the Coulomb friction torque and the follow-up parameter; wherein the optimized plunger pump torque calculation formula includes a first coefficient and a second coefficient, and the first coefficient and the second coefficient are dynamic fitting coefficients, which are dynamically adjusted as the health state of the plunger pump changes; The monitoring module is used to monitor the real-time operating parameters of the plunger pump, calculate the first coefficient and the second coefficient based on the real-time operating parameters, and input the first coefficient and the second coefficient into a neural network to construct a state monitoring model to evaluate the operating state of the plunger pump.

Images