Hydraulic pump fluid flow pulsation characteristic characterization method based on digital twinborn technology

Abstract

The invention provides a hydraulic pump fluid flow pulsation characteristic characterization method based on a digital twin technology, and relates to the technical field of fluid pressure measurement. The method comprises the following steps: firstly, establishing a theoretical structure model of a tested hydraulic pump by using AMEsim simulation software, secondly, establishing a pump source pressure pulsation test system of the tested hydraulic pump, simulating load change by using a throttle valve, and acquiring a pressure pulsation signal, a temperature signal and an average flow signal of fluid at an outlet of the tested hydraulic pump by using a data acquisition system; the collected signals are processed to serve as input parameters of a theoretical structure model of the tested hydraulic pump; and finally, performing simulation calculation on the theoretical structure model of the tested hydraulic pump, modifying simulation model parameters, comparing a pressure pulsation curve obtained by simulation with an actually measured pressure pulsation curve, and gradually determining final parameters of the theoretical structure model parameters of the tested hydraulic pump. The method is easy to implement and convenient to operate, the requirement for engineering precision can be met, and the experiment cost and the time cost are greatly saved.

Description

Technical Field

[0001] The present invention relates to the field of fluid pressure measurement technology, and in particular to a method for characterizing fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology. Background Art

[0002] The hydraulic pump is the main power source for the output of energy (flow and pressure) in the hydraulic system. Due to the characteristics of its own structure, the fluid it outputs produces flow pulsation. The periodic pulsation of the instantaneous flow of the hydraulic pump causes the pulsation of the fluid in the hydraulic pipeline system. The periodic flow pulsation forms fluid pressure pulsation under the joint action of the hydraulic pump, pipeline and load impedance. The pressure pulsation generated by the output fluid of the hydraulic pump may cause resonance of the hydraulic pipeline system; considering the multi-source excitation formed under the influence of the external environment, it may further cause the flapping behavior of the pipeline system. Resonance or flapping vibration will have a great impact on the safety and reliability of the hydraulic pipeline system. At the least, it will cause local deformation of the hydraulic pipeline and reduce the working life of the hydraulic accessories. At the worst, it will cause the hydraulic pipeline to rupture or collide, the clamp to tear, the connection joint to be pulled off, and the ferrule to break, thereby causing the failure of the entire pipeline system, or even the paralysis of the entire hydraulic system. Short-term pump source fluid pressure pulsation excitation may not have much impact on the pipeline, but long-term pump source fluid pressure pulsation excitation will cause fatigue damage to the pipeline and may even cause serious accidents.

[0003] Therefore, it is particularly important to develop a scientific and systematic method for characterizing the flow pulsation characteristics of hydraulic pump fluids. This method not only helps to deeply understand the generation mechanism of hydraulic pump fluid noise, but also has important significance for guiding the low-noise structural design optimization of hydraulic pumps. In addition, it can also provide a theoretical basis for the active control research of pump source fluid pressure pulsation characteristics, thereby effectively eliminating the destructive effects that pump source fluid pressure pulsation may have on hydraulic pipelines and the entire hydraulic system.

[0004] Existing flow meter tests can only characterize the average flow pulsation of the hydraulic pump output, but cannot measure the instantaneous flow pulsation of the hydraulic pump output. There are several existing flow pulsation test methods: one is to use a fast-response flow sensor to measure the flow pulsation; the other is to use a corresponding flow pulsation test device. Among them, EDGE et al. proposed the "secondary source method" to test the flow pulsation of the hydraulic pump. This method introduces a "secondary source" with adjustable impedance to calculate the pump source impedance of the pump under test, and calculates the flow pulsation of the pump source by considering the dynamic characteristics of the hydraulic pipeline. This method is simple to test, but because its data processing process is very complicated, it has high requirements for the components used in the test, and it is difficult to test in practice. BOWNS et al. proposed a method of using multiple pipes of different lengths to test the impedance and flow pulsation of the pump source. This method requires many pipes of different lengths, and multiple measurements are required to obtain the calculation results. KOJIMA et al. proposed a "dual system / dual pressure" flow pulsation test device, but for the pump to be tested with a complex outlet pipeline, its test accuracy is low. Yu Jinghong and others proposed to use the "practical approximation method" to test the flow pulsation of axial piston pumps. The disadvantage of this method is still that the flow pulsation test accuracy of the pump to be tested with complex outlet pipelines is low. ERICSON proposed the "source admittance" method. This method assumes that flow pulsation is generated at a certain point in the pump outlet pipeline, tests the pressure pulsation at that point, and obtains the pump source impedance and pump source flow pulsation by solving the equation. This method improves the test accuracy of the above several methods for complex outlet pipeline flow pulsation, but the location of the generated flow pulsation is difficult to determine. Therefore, for axial piston pumps with a frequency higher than 1kHz, the test results are not accurate. The third is to use an appropriate method to attenuate the amplitude of the flow pulsation to a sufficiently small value, then measure it with a flowmeter, and perform error correction on the measured value.

[0005] Obviously, the above flow pulsation test methods cannot accurately characterize the characteristics of the instantaneous flow pulsation of the hydraulic pump, and can only obtain the measurement results of the average flow. However, in the field of fluid pulsation simulation, the instantaneous flow pulsation model is one of the irreplaceable and necessary input conditions. Therefore, a mapping-reproduction idea can be used to combine testing and simulation: by measuring the pressure, temperature, average flow and other parameters of the oil in the actual hydraulic system, combined with the known properties of the hydraulic oil, the established simulation model is parameterized and corrected, and the flow pulsation is indirectly characterized by means of simulation calculation, thereby successfully solving this practical problem. Summary of the invention

[0006] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art and to provide a method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology. The method can more simply characterize the flow pulsation generated at the outlet of the hydraulic pump, thereby meeting the engineering precision requirements and providing technical support for the control of hydraulic pump fluid pressure pulsation and the research on vibration and noise reduction of the hydraulic system.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology. First, the theoretical structural model of the hydraulic pump under test is established using AMEsim simulation software. The input parameters required for the theoretical structural model include the motor speed driving the hydraulic pump, the pressure pulsation and average flow at the outlet of the hydraulic pump under test, and the density, bulk modulus, viscosity, and temperature of the hydraulic medium. Secondly, build a pump source pressure pulsation test system for the tested hydraulic pump, including the tested hydraulic pump, hydraulic pipelines connected to various hydraulic components, pressure sensors, flow sensors, temperature sensors, pressure gauges, throttle valves, oil tanks, A / D converters, data acquisition cards, and signal processing systems; the oil inlet of the tested hydraulic pump is connected to the oil outlet of the oil tank, and the oil outlet is connected to the hydraulic pipeline; the pressure sensor, flow sensor, and temperature sensor are installed in sequence on the hydraulic pipeline near the outlet of the tested hydraulic pump, and the data output ends of the three sensors are connected to the input end of the data acquisition card after passing through an A / D converter; a pressure gauge is installed at the outlet of the hydraulic pipeline, and then connected to the throttle valve. The oil inlet of the throttle valve; the entire hydraulic system simulates the load pressure of the entire hydraulic system by adjusting the opening size of the throttle valve, and the load pressure is displayed and read in real time through the pressure gauge; the pressure sensor, flow sensor, and temperature sensor are used to measure the pressure pulsation signal, average flow signal, and temperature signal of the outlet fluid of the tested hydraulic pump, and then each signal is collected by the data acquisition card after passing through the A / D converter. The collected signals are processed by the signal processing system as the input parameters of the theoretical structural model of the tested hydraulic pump, including the measured temperature of the hydraulic medium, the pressure pulsation at the pump outlet, and the average flow rate. Other input parameters are known quantities; Finally, the theoretical structural model of the hydraulic pump under test is simulated and calculated through the hydraulic pump simulation model system to approximate the corresponding flow pulsation and pressure pulsation. By modifying the simulation model parameters, the simulated pressure pulsation curve is compared with the measured pressure pulsation curve. When the error value is within the allowable range, the flow pulsation of the simulated fluid is the actual output flow pulsation of the hydraulic pump under test. At this time, the theoretical structural model parameters of the hydraulic pump under test are the final determined parameters.

[0008] Furthermore, the theoretical structural model of the hydraulic pump under test is specifically as follows: For the theoretical structural model of the gear pump, the average flow rate and the first three harmonic pulsation frequencies of the gear pump are superimposed to perform fitting modeling. Specifically, a constant signal module and three sinusoidal signals are superimposed through a summation module, and then the hydraulic flow transmitter module and the empty volume cavity module are connected. At this time, the overall modeling of the gear pump is completed; the entire gear pump hydraulic system should also be connected to the throttle valve module to simulate the load pressure, and the throttle valve module input is determined by the constant signal module; finally, the oil tank is connected to complete the gear pump hydraulic system modeling; The theoretical structural model of the plunger pump hydraulic system includes a plunger model part, a power model part, and a load model part; the plunger model part is composed of a plunger module; the power model part is composed of a motor module, a rotary spring module, and a rotary load module; the load model part simulates the load pressure by a throttle valve module, and the throttle valve module input is determined by a constant signal module; finally, the oil tank is connected to complete the modeling of the plunger pump hydraulic system.

[0009] Furthermore, in the pump source pressure pulsation test system, the hydraulic pump under test and the hydraulic pipelines connected to each hydraulic element are the hydraulic part of the system, the hydraulic pump under test is driven by an electric motor, and the speed of the electric motor is adjusted by a frequency converter; The data acquisition card is respectively connected to the pressure sensor, the flow sensor, and the temperature sensor for collecting the actual working conditions of the measured hydraulic system, including the pressure pulsation signal of the hydraulic pump outlet fluid, the average flow signal, and the temperature signal of the hydraulic oil; The signal processing system reads, processes, analyzes and stores the data collected by the data acquisition card from each sensor. The reading includes reading the average flow of the hydraulic system and the temperature information of the hydraulic oil; the processing includes digitally filtering the pressure signal to obtain the time domain and frequency domain information of the pressure signal; the analysis and storage includes extracting the pressure mean in the time domain information of the pressure signal, the first three order pressure amplitudes in the frequency domain information and the average flow value measured by the flow sensor, and storing the extracted data so that the corresponding simulation model can be parameterized according to these data to facilitate subsequent simulation calculations.

[0010] Furthermore, the oil outlet of the tested hydraulic pump is connected to a relief valve, which is used as a safety valve.

[0011] Furthermore, a filter is provided at the oil outlet of the throttle valve, and the oil outlet of the filter is connected to the oil return pipeline of the oil tank.

[0012] Furthermore, the installation distance between the pressure sensor and the oil outlet of the hydraulic pump under test is 20 mm to 30 mm; The flow sensor and temperature sensor are installed between the pressure sensor and the pressure gauge.

[0013] Furthermore, the hydraulic pump simulation model system performs modeling and analysis according to the actual layout of the pump source pressure pulsation test system, and performs modeling based on the instantaneous flow model of the hydraulic pump under test, while simulating changes in system pressure by adjusting the corresponding throttle valve; the setting of oil parameters is performed through the actual oil parameters and the data measured by the sensor; the setting of the length and diameter size parameters of the pipeline components are all set according to the actual surveying and mapping of the hydraulic components.

[0014] The beneficial effect of adopting the above technical scheme is that: the method for characterizing the pulsation characteristics of the fluid flow of a hydraulic pump based on the digital twin technology provided by the present invention uses the AMEsim simulation software to model the measured hydraulic pump based on the theoretical output flow. The model is based on a multi-scale mapping idea. As a digital twin of the physical hydraulic pump, it can dynamically simulate the main body in real time and reproduce the state of the main body and the external environmental conditions. The simulated pressure pulsation curve is compared with the measured pressure pulsation curve. When the error meets the engineering accuracy requirements, it is considered that the digital twin is basically consistent with the parameters and state of the measured hydraulic pump. The flow pulsation curve calculated by simulation is the flow pulsation output of the measured hydraulic pump, which realizes the characterization of the pulsation characteristics of the fluid flow of the hydraulic pump under different working conditions. By establishing a digital twin with a mapping relationship with the measured hydraulic pump, the influence on the main body is avoided, the impedance work of measuring and calculating the hydraulic pump, pipeline, etc. is omitted, the experimental cost and time cost are greatly saved, and the work efficiency is improved. Since the AMEsim software has its own analysis and calculation of the continuity of the fluid and the propagation characteristics of the pressure wave, the simulation method is simple, feasible and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 An overall flow chart of a method for characterizing fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology provided in an embodiment of the present invention; Figure 2 A schematic diagram of a pump source pressure pulsation test system and a simulation model system provided in an embodiment of the present invention; Figure 3 A schematic diagram of a theoretical structural model of a gear pump in a simulation model system provided in an embodiment of the present invention; Figure 4 Schematic diagram of the theoretical structural model of the plunger pump in the simulation model system provided in an embodiment of the present invention.

[0016] In the figure: 1. Pump source pressure pulsation test system; 2. Hydraulic pump simulation model system; 3. Hydraulic pump under test; 4. Electric motor; 5. Frequency converter; 6. Overflow valve; 7. Hydraulic pipeline; 8. Pressure sensor; 9. Flow sensor; 10. Temperature sensor; 11. Pressure gauge; 12. Throttle valve; 13. Filter; 14. Oil tank; 15. A / D converter; 16. Data acquisition card; 17. Signal processing system. DETAILED DESCRIPTION

[0017] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0018] First, connect the measured hydraulic pipeline with the hydraulic pump to be tested, install the three sensors, and connect the three sensors to the data acquisition card respectively, adjust the inverter parameters, and let the system run at no load for 5-10 minutes. The working pressure of the hydraulic system can be adjusted by adjusting the opening size of the throttle valve. The system pressure can be read in real time by the pressure gauge. After waiting for the system to run smoothly, the data acquisition card is used to collect the signals of the three sensors and transmit them to the signal processing system. At this time, the measured hydraulic system can be closed to store and process the signals just collected. Secondly, the simulation model system is digitally twinned according to the layout of the actual hydraulic system and the type of the hydraulic pump being measured. The parameters of the twin simulation model are set and modified according to the actual parameters of the hydraulic oil and the pressure, average flow and temperature signals collected by the measured hydraulic system. After the above settings are completed, the twin model can be simulated and calculated. The pressure pulsation curve of the twin simulation model is compared with the pressure pulsation output curve of the measured hydraulic pump. The twin model parameters are corrected and the calculation is continuously iterated. After the error meets the engineering accuracy requirements, the digital twin model is consistent with the structure and state of the physical hydraulic pump. The simulated flow pulsation curve can be regarded as the flow pulsation output of the measured hydraulic pump, realizing the characterization of the flow pulsation characteristics of the hydraulic pump fluid under different working conditions. The simulation results of this method are easy to read and the data can also be exported for subsequent research. The specific process is as follows: Figure 1 shown.

[0019] Digital twin technology consists of three parts: physical entity, digital model and data connection. Physical entity is an entity in the real world, such as machines, equipment, factories, etc. Digital model is the core of digital twin, which is a virtual model corresponding to the physical entity. Data connection is the technology to connect the physical entity and the digital model, including sensors, data acquisition, data storage and data analysis.

[0020] In this embodiment, the physical entity part is the components in the pump source pressure pulsation test system, including the hydraulic pump under test, hydraulic pipelines connected to each hydraulic component, throttle valve, overflow valve, filter, and oil tank; the digital model part is a theoretical structural model of the hydraulic pump under test established using AMEsim simulation software; the data connection part is a pressure sensor, flow sensor, temperature sensor, data acquisition card, and signal processing system.

[0021] The method of characterizing the fluid flow pulsation characteristics of hydraulic pumps based on digital twin technology is used to solve the problem that the instantaneous flow of hydraulic pumps cannot be measured. At present, the theoretical instantaneous flow pulsation expression of the gear pump under any working condition has been derived: ;

[0022] in, q 0 is the steady-state average flow rate of the pump source fluid (L / min); q i For the i The amplitude of the step flow pulsation fluctuation (L / min); f i For the i Frequency of step flow pulsation (Hz); n is the harmonic number of flow pulsation.

[0023] The actual situation shows that the first three-order harmonic pulsation accounts for the main part. Therefore, the core of characterizing instantaneous flow pulsation is to obtain the accurate amplitude of the first three-order harmonic pulsation signal, that is, q 1. q 2. q 3, and then the instantaneous flow pulsation model of the hydraulic pump fluid is obtained.

[0024] When applying this method, the parameters set in the theoretical structural model of the gear pump include: setting the throttle valve opening diameter, hydraulic medium temperature, density, bulk modulus and viscosity according to the measured pressure pulsation, setting the constant signal module, sine signal module amplitude, frequency, and pipeline component diameter and length according to the average flow rate. The parameters set in the theoretical structural model of the plunger pump include: setting the throttle valve opening diameter, hydraulic medium temperature, density, bulk modulus and viscosity, pipeline component diameter, length, motor speed of the driving pump, and plunger parameters according to the measured pressure pulsation.

[0025] The pump source pressure pulsation test system includes a tested hydraulic pump 3, a motor 4, a frequency converter 5, a relief valve 6, a hydraulic pipeline 7, a pressure sensor 8, a flow sensor 9, a temperature sensor 10, a pressure gauge 11, a throttle valve 12, a filter 13, an oil tank 14, an A / D converter 15, a data acquisition card 16 and a signal processing system 17; wherein, the oil inlet of the tested hydraulic pump 3 is connected to the oil outlet pipeline of the oil tank 14, the oil outlet is connected to the relief valve 6 and the hydraulic pipeline 7, the hydraulic pipeline 7 is sequentially installed with a pressure sensor 8, a flow sensor 9 and a temperature sensor 10 near the outlet of the tested hydraulic pump 3, and the data output ends of the three sensors are respectively installed with an A / D converter 15, which performs analog-to-digital conversion on the sensor acquisition signal and then inputs it into the data acquisition card 16. The A / D converter also has the function of filtering and removing noise signals to improve the accuracy of the signal; in addition, the signal can be amplified during the conversion process to ensure that no information is lost during the conversion process. A pressure gauge 11 is installed at the outlet of the hydraulic pipeline 7, which is then connected to the oil inlet of the throttle valve 12. The oil outlet of the throttle valve 12 is connected to the oil inlet of the filter 13, and the oil outlet of the filter 13 is connected to the return oil pipeline of the oil tank 14. The frequency converter 5 can adjust the speed of the motor driving the hydraulic pump under test according to instructions, thereby supplying hydraulic oil to the entire hydraulic system. Since the frequency converter can control the speed of the motor driving the pump under test, the hydraulic pump under test can be controlled to produce hydraulic oil with different pulsation frequencies. The pressure sensor 8, flow sensor 9, and temperature sensor 10 collect the corresponding data of the hydraulic oil in real time. After analog-to-digital conversion by the A / D converter 15, the data is collected using the data acquisition card 16, and then stored and processed by the signal processing system 17. The data signal output of the above-mentioned pump source pressure pulsation test system is used as the input of the hydraulic pump simulation model system, and the flow pulsation is characterized by the simulation results, such as Figure 2 shown.

[0026] like Figure 3 and Figure 4 As shown, the hydraulic pump simulation model system includes a gear pump simulation analysis module and a plunger pump simulation analysis module. The modeling of the two modules is based on the mapping concept of digital twin technology and is modeled according to the actual situation of the hydraulic system being tested. It can reflect the layout of the actual hydraulic system and can set and modify parameters according to the actual situation.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. A method for characterizing the pulsation characteristics of fluid flow in a hydraulic pump based on digital twin technology, characterized in that: Firstly, the theoretical structural model of the tested hydraulic pump (3) is established by using AMEsim simulation software. The input parameters required for the theoretical structural model include the speed of the motor driving the hydraulic pump, the pressure pulsation and average flow rate at the outlet of the tested hydraulic pump (3), and the density, bulk modulus, viscosity, and temperature of the hydraulic medium. Secondly, a pump source pressure pulsation test system (1) of the tested hydraulic pump (3) is constructed, comprising the tested hydraulic pump (3), a hydraulic pipeline (7) connected to each hydraulic component, a pressure sensor (8), a flow sensor (9), a temperature sensor (10), a pressure gauge (11), a throttle valve (12), an oil tank (14), an A / D converter (15), a data acquisition card (16), and a signal processing system (17); the oil inlet of the tested hydraulic pump (3) is connected to the oil outlet pipeline of the oil tank (14), and the oil outlet is connected to the hydraulic pipeline (7); the pressure sensor (8), the flow sensor (9) and the temperature sensor (10) are sequentially installed on the hydraulic pipeline (7) near the outlet of the tested hydraulic pump (3), and the data output ends of the three sensors are respectively connected to the input end of the data acquisition card (16) after passing through an A / D converter (15); A pressure gauge (11) is installed at the outlet of the hydraulic pipeline (7), and is connected to the oil inlet of the throttle valve (12); the entire hydraulic system simulates and controls the load pressure of the entire hydraulic system by adjusting the opening size of the throttle valve (12), and the load pressure is displayed and read in real time through the pressure gauge (11); a pressure sensor (8), a flow sensor (9), and a temperature sensor (10) are used to measure the pressure pulsation signal, the average flow signal, and the temperature signal of the hydraulic oil at the outlet of the tested hydraulic pump (3), respectively, and then each signal is collected by the data acquisition card (16) after passing through the A / D converter (15), and the collected signal is processed by the signal processing system (17) as the input parameters of the theoretical structural model of the tested hydraulic pump (3), including the measured temperature of the hydraulic medium, the pressure pulsation at the pump outlet, and the average flow rate, and the other input parameters are known quantities; Finally, the theoretical structural model of the tested hydraulic pump (3) is simulated and calculated by the hydraulic pump simulation model system (2), and the corresponding flow pulsation and pressure pulsation are approximately obtained. By modifying the simulation model parameters, the simulated pressure pulsation curve is compared with the measured pressure pulsation curve. When the error value is within the allowable range, the flow pulsation of the simulated fluid is the output flow pulsation of the actual tested hydraulic pump (3). At this time, the theoretical structural model parameters of the tested hydraulic pump (3) are the final determined parameters.

2. The method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology according to claim 1 is characterized in that: The theoretical structural model of the tested hydraulic pump (3) is specifically as follows: For the theoretical structural model of the gear pump, the average flow rate and the first three harmonic pulsation frequencies of the gear pump are superimposed to perform fitting modeling. Specifically, a constant signal module and three sinusoidal signals are superimposed through a summing module to build a model. The hydraulic flow transmitter module and the empty volume cavity module are then connected to complete the overall modeling of the gear pump. The entire gear pump hydraulic system should also be connected to a throttle valve (12) module to simulate the load pressure. The input of the throttle valve (12) module is determined by the constant signal module. Finally, the oil tank (14) is connected to complete the modeling of the gear pump hydraulic system. The theoretical structural model of the plunger pump hydraulic system includes a plunger model part, a power model part, and a load model part; the plunger model part is formed by connecting a plunger module; the power model part is formed by connecting a motor module, a rotary spring module, and a rotary load module; the load model part simulates the load pressure by a throttle valve (12) module, and the input of the throttle valve (12) module is determined by a constant signal module; finally, the plunger pump hydraulic system modeling is completed by connecting to the oil tank (14).

3. The method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology according to claim 1 is characterized in that: In the pump source pressure pulsation test system (1), the hydraulic pump (3) to be tested and the hydraulic pipelines (7) connected to the hydraulic components are the hydraulic part of the system. The hydraulic pump (3) to be tested is driven by an electric motor (4), and the speed of the electric motor (4) is adjusted by a frequency converter (5); The data acquisition card (16) is respectively connected to the pressure sensor (8), the flow sensor (9), and the temperature sensor (10) for collecting actual working conditions of the measured hydraulic system, including a pressure pulsation signal of the fluid at the outlet of the hydraulic pump, an average flow signal, and a temperature signal of the hydraulic oil; The signal processing system (17) reads, processes, analyzes and stores the data collected by the data acquisition card (16) from each sensor, wherein the reading includes reading the average flow of the hydraulic system and the temperature information of the hydraulic oil; the processing includes digitally filtering the pressure signal to obtain the time domain and frequency domain information of the pressure signal; the analysis and storage includes extracting the pressure mean value in the time domain information of the pressure signal, the first three order pressure amplitudes in the frequency domain information and the average flow value measured by the flow sensor (9), and storing the extracted data so that the corresponding simulation model can be parameterized according to these data to facilitate subsequent simulation calculations.

4. The method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology according to claim 3 is characterized in that: The oil outlet of the tested hydraulic pump (3) is connected to a relief valve (6) which serves as a safety valve.

5. The method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology according to claim 4 is characterized in that: The oil outlet of the throttle valve (12) is provided with a filter (13), and the oil outlet of the filter (13) is connected to the oil return pipeline of the oil tank (14).

6. The method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology according to claim 5 is characterized in that: The installation distance between the pressure sensor (8) and the oil outlet of the hydraulic pump (3) to be tested is 20 mm to 30 mm; The flow sensor (9) and the temperature sensor (10) are installed between the pressure sensor (8) and the pressure gauge (11).

7. The method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology according to claim 1, characterized in that: The hydraulic pump simulation model system (2) performs modeling analysis according to the actual arrangement of the pump source pressure pulsation test system (1), performs modeling based on the instantaneous flow model of the tested hydraulic pump (3), and simulates the change of system pressure by adjusting the corresponding throttle valve (12); the setting of oil parameters is performed based on the actual oil parameters and the data measured by the sensor; the setting of the length and diameter size parameters of the pipeline components are all performed according to the actual surveying and mapping of the hydraulic components.

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