Hydraulic pump fluid flow pulsation characteristic representation method based on digital twinning technology

Abstract

The application provides a hydraulic pump fluid flow pulsation characteristic representation method based on digital twin technology, and relates to the technical field of fluid pressure measurement. First, a theoretical structure model of the measured hydraulic pump is established by using AMEsim simulation software; second, a pump source pressure pulsation test system of the measured hydraulic pump is built, a throttle valve is used to simulate load change, and a data acquisition system is used to collect pressure pulsation signals, temperature signals and average flow signals of the outlet fluid of the measured hydraulic pump; the collected signals are processed and used as input parameters of the theoretical structure model of the measured hydraulic pump; finally, the theoretical structure model of the measured hydraulic pump is simulated and calculated, the simulation model parameters are modified, the simulation obtained pressure pulsation curve is compared with the measured pressure pulsation curve, and the final parameters of the theoretical structure model parameters of the measured hydraulic pump are gradually determined. The application is simple to realize, convenient to operate, can meet the requirement of engineering precision, and greatly saves experimental cost and time cost.

Description

Technical Field

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

[0002] Hydraulic pumps are the primary power source for the energy (flow and pressure) output of hydraulic systems. Due to their inherent structural characteristics, the fluid they output experiences flow pulsations. The periodic fluctuations in the instantaneous flow rate of the hydraulic pump cause pulsations in the fluid within the hydraulic pipeline system. These periodic flow pulsations, under the combined influence of the hydraulic pump, pipeline, and load impedance, create fluid pressure pulsations. These pressure pulsations generated by the hydraulic pump's output fluid may induce resonance in the hydraulic pipeline system. Considering the multi-source excitation caused by external environmental influences, this may further induce flapping behavior in the pipeline system. Resonance or flapping has a significant impact on the safety and reliability of hydraulic pipeline systems. At best, it can cause localized deformation of the hydraulic pipeline and reduce the service life of hydraulic accessories; at worst, it can lead to hydraulic pipeline rupture or collision, clamp tearing, connector pull-out, and sleeve breakage, resulting in 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 a significant impact on the pipeline, but long-term pump-source fluid pressure pulsation excitation can cause fatigue damage to the pipeline and may even lead to serious accidents.

[0003] Therefore, developing a scientific and systematic method for characterizing the fluid flow pulsation characteristics of hydraulic pumps is crucial. This method not only helps to deepen the understanding of the generation mechanism of hydraulic pump fluid noise, but also has important significance for guiding the optimization of low-noise structural design of hydraulic pumps. Furthermore, it can provide a theoretical basis for the active control research of pump source fluid pressure pulsation characteristics, thereby effectively eliminating the potentially destructive effects of pump source fluid pressure pulsation on hydraulic pipelines and the entire hydraulic system.

[0004] Existing flowmeter tests can only characterize the average flow pulsation of hydraulic pump output, but cannot measure the instantaneous flow pulsation. Current methods for testing flow pulsation include: one is using a fast-response flow sensor; the other is employing appropriate flow pulsation testing devices. These include the "secondary source method" proposed by EDGE et al., which uses an adjustable impedance "secondary source" to calculate the pump source impedance and calculates the flow pulsation by considering the dynamic characteristics of the hydraulic pipeline. This method is simple to test, but its data processing is very complex, and it requires high-quality components, making practical testing difficult. BOWNS et al. proposed using multiple pipes of different lengths to test the pump source impedance and flow pulsation. This method requires many pipes of different lengths and multiple measurements to obtain the calculation results. KOJIMA et al. proposed a "dual-system / dual-pressure" flow pulsation testing device, but its testing accuracy is low for pumps with complex outlet pipelines. Yu Jinghong et al. proposed using a "practical approximation method" to test the flow pulsation of axial piston pumps. However, this method still suffers from low accuracy in testing flow pulsation for pumps with complex outlet pipes. Ericson proposed the "source impedance" method, which assumes flow pulsation occurs at a certain point in the pump outlet pipe, tests the pressure pulsation at that point, and obtains the pump source impedance and flow pulsation by solving equations. This method improves the accuracy of the above methods for testing flow pulsation in complex outlet pipes; however, the location of the generated flow pulsation is difficult to determine, therefore the test results are inaccurate for axial piston pumps with frequencies higher than 1kHz. A third approach involves using appropriate methods to attenuate the amplitude of the flow pulsation to a sufficiently small value, then measuring it with a flow meter, and correcting the measurement values ​​for errors.

[0005] Clearly, the aforementioned flow pulsation testing methods cannot accurately characterize the instantaneous flow pulsation characteristics of a hydraulic pump; they can only obtain the measurement results of the average flow rate. However, in the field of fluid pulsation simulation, the instantaneous flow pulsation model is an irreplaceable and necessary input condition. Therefore, a mapping-reproduction approach can be used to combine testing and simulation: by measuring parameters such as pressure, temperature, and average flow rate of the oil in the actual hydraulic system, and combining this with known hydraulic oil properties, the parameters of the established simulation model are set and corrected. Flow pulsation is then indirectly characterized through simulation calculations, thus successfully solving this practical problem. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology. This method can more easily characterize the flow pulsation generated at the outlet of the hydraulic pump, meet the engineering accuracy requirements, and provide technical support for the control of fluid pressure pulsation in hydraulic pumps and the research on vibration reduction and noise reduction of hydraulic systems.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology is proposed. First, a 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 rate at the outlet of the hydraulic pump under test, and the density, bulk modulus, viscosity, and temperature of the hydraulic medium.

[0009] Next, a pump source pressure pulsation test system for the hydraulic pump under test is constructed, including the hydraulic pump under test, hydraulic pipelines connected to various hydraulic components, pressure sensors, flow sensors, temperature sensors, pressure gauges, throttle valves, an oil tank, an A / D converter, a data acquisition card, and a signal processing system. The oil inlet of the hydraulic pump under test is connected to the oil outlet pipeline of the oil tank, and the oil outlet is connected to the hydraulic pipeline. Pressure sensors, flow sensors, and temperature sensors are sequentially installed on the hydraulic pipeline near the outlet of the hydraulic pump under test. The data outputs of the three sensors are connected to the input of the data acquisition card after passing through an A / D converter. A pressure gauge is installed at the outlet of the hydraulic pipeline, followed by a throttle valve. The inlet of the flow valve; the entire hydraulic system simulates and controls 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 by the pressure gauge; the pressure pulsation signal, average flow signal and hydraulic oil temperature signal of the fluid at the outlet of the tested hydraulic pump are measured by pressure sensor, flow sensor and temperature sensor respectively. Then each signal is acquired by data acquisition card after passing through A / D converter. The acquired signals are processed by signal processing system and used as input parameters for the theoretical structural model of the tested hydraulic pump, including the measured temperature of hydraulic medium, pressure pulsation at pump outlet and average flow. Other input parameters are known quantities;

[0010] Finally, the theoretical structural model of the hydraulic pump under test is simulated and calculated using a 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 fluid obtained by the simulation 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.

[0011] Furthermore, the theoretical structural model of the hydraulic pump under test is as follows:

[0012] For the theoretical structural model of the gear pump, the model is fitted by superimposing the average flow rate with the first three harmonic pulsation frequencies of the gear pump. Specifically, it is constructed by superimposing a constant signal module and three sinusoidal signals through a summation module. Then, a hydraulic flow transmitter module and an empty cavity module are connected to complete the overall modeling of the gear pump. The entire gear pump hydraulic system should also be connected to a throttle valve module to simulate the load pressure. The input of the throttle valve module is determined by the constant signal module. Finally, the oil tank is connected to complete the modeling of the gear pump hydraulic system.

[0013] The theoretical structural model of the piston pump hydraulic system includes a piston model, a power model, and a load model. The piston model is composed of piston modules connected together. The power model is composed of a motor module, a rotary spring module, and a rotary load module connected together. The load model uses a throttle valve module to simulate the load pressure, and the input of the throttle valve module is determined by a constant signal module. Finally, the oil tank is connected to complete the modeling of the piston pump hydraulic system.

[0014] Furthermore, in the pump source pressure pulsation test system, the hydraulic pump under test and the hydraulic pipelines connected to each hydraulic component constitute 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.

[0015] The data acquisition card is connected to the pressure sensor, flow sensor and temperature sensor respectively to collect the actual working conditions of the measured hydraulic system, including the pressure pulsation signal, average flow signal and temperature signal of the hydraulic pump outlet fluid.

[0016] The signal processing system reads, processes, analyzes, and stores data collected from various sensors by the data acquisition card. The reading includes reading the average flow rate 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 include extracting the average pressure value from the time domain information of the pressure signal, the first three pressure amplitudes from the frequency domain information, and the average flow rate value measured by the flow sensor. The extracted data is stored so that the parameters of the corresponding simulation model can be set according to these data, which facilitates subsequent simulation calculations.

[0017] Furthermore, the oil outlet of the hydraulic pump under test is connected to an overflow valve, which is used as a safety valve.

[0018] Furthermore, the outlet of the throttle valve is equipped with a filter, and the outlet of the filter is connected to the return oil line of the oil tank.

[0019] Furthermore, the installation distance between the pressure sensor and the oil outlet of the hydraulic pump under test is 20mm to 30mm;

[0020] The flow sensor and temperature sensor are installed between the pressure sensor and the pressure gauge.

[0021] Furthermore, the hydraulic pump simulation model system performs modeling and analysis based on the actual layout of the pump source pressure pulsation test system. The model is based on the instantaneous flow model of the hydraulic pump under test, and the system pressure changes are simulated by adjusting the corresponding throttle valve. The oil parameters are set based on the actual oil parameters and the data measured by the sensor. The length and diameter parameters of the pipeline components are set according to the actual measurement of the hydraulic components.

[0022] The beneficial effects of adopting the above technical solution are as follows: The hydraulic pump fluid flow pulsation characteristic characterization method based on digital twin technology provided by this invention uses AMEsim simulation software to model the tested hydraulic pump based on the theoretical output flow rate. This model is based on a multi-scale mapping concept and serves as a digital twin of the physical hydraulic pump. It can dynamically simulate the physical pump in real time, reproducing the state of the physical pump and the external environmental conditions. By comparing the simulated pressure pulsation curve with the measured pressure pulsation curve, when the error meets the engineering accuracy requirements, it is considered that the parameters and state of the digital twin and the tested hydraulic pump are basically consistent. The flow pulsation curve calculated by simulation is the flow pulsation output of the measured hydraulic pump, realizing the characterization of the fluid flow pulsation characteristics of the hydraulic pump under different working conditions. By establishing a digital twin with a mapping relationship with the tested hydraulic pump, the influence on the physical pump is avoided, and the work of measuring and calculating the impedance of the hydraulic pump, pipelines, etc. is eliminated, greatly saving experimental costs and time costs and improving work efficiency. Since AMEsim software has built-in analysis and calculation of fluid continuity and pressure wave propagation characteristics, simulation is a simple, feasible, and accurate method. Attached Figure Description

[0023] Figure 1 A flowchart illustrating the overall process of the hydraulic pump fluid flow pulsation characteristic characterization method based on digital twin technology provided in this embodiment of the invention;

[0024] Figure 2 This is a schematic diagram of the pump source pressure pulsation testing system and simulation model system provided in an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of the theoretical structural model of the gear pump in the simulation model system provided in this embodiment of the invention;

[0026] Figure 4 A schematic diagram of the theoretical structural model of the plunger pump in the simulation model system provided in the embodiments of the present invention.

[0027] In the diagram: 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. Relief 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 Implementation

[0028] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0029] First, connect the measured hydraulic pipeline to the hydraulic pump under test, install the three sensors, and connect the three sensors to the data acquisition card respectively. Adjust the inverter parameters and run the system under no-load for 5-10 minutes. The working pressure of the hydraulic system is adjusted by regulating the opening size of the throttle valve. The system pressure can be read in real time by the pressure gauge. After the system is running smoothly, the signals from the three sensors are collected using a data acquisition card and transmitted to the signal processing system. At this time, the measured hydraulic system can be shut down, and the collected signals are stored and processed. Next, a digital twin model is created for the simulation model system according to the actual layout of the hydraulic system and the type of the hydraulic pump being tested. 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 parameters of the twin model are corrected and iterative calculations are continuously performed. After the error meets the engineering accuracy requirements, the digital twin model matches the structure and state of the physical hydraulic pump. The flow pulsation curve calculated by simulation can be regarded as the flow pulsation output of the measured hydraulic pump, realizing the characterization of the fluid flow pulsation characteristics of the hydraulic pump under different working conditions. The simulation results obtained by this method are easy to read and can also be exported for subsequent research. The specific process is as follows: Figure 1 As shown.

[0030] Digital twin technology comprises three parts: physical entities, digital models, and data connectivity. Physical entities are real-world objects, such as machines, equipment, and factories. The digital model is the core of a digital twin; it's a virtual model that corresponds to the physical entity. Data connectivity is the technology that connects the physical entity and the digital model, including technologies such as sensors, data acquisition, data storage, and data analysis.

[0031] 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, relief valve, filter, and oil tank; the digital model part is the theoretical structural model of the hydraulic pump under test established using AMEsim simulation software; the data connection part includes pressure sensor, flow sensor, temperature sensor, data acquisition card, and signal processing system.

[0032] The reason for developing a method based on digital twin technology to characterize the fluid flow pulsation characteristics of hydraulic pumps is to solve the problem of the inability to measure the instantaneous flow rate of hydraulic pumps. Currently, a theoretical derivation has been obtained for the theoretical instantaneous flow pulsation expression of gear pumps under arbitrary operating conditions:

[0033] ;

[0034] in, q 0 represents the steady-state average flow rate (L / min) of the pump source fluid; q i For the first i The amplitude of the flow rate pulsation (L / min); f i For the first i The frequency (Hz) of the flow pulsation; n This represents the harmonic number of the flow pulsation.

[0035] In practice, the first three harmonic pulsations constitute the majority of the flow. Therefore, the key to characterizing instantaneous flow pulsations is obtaining accurate amplitude values ​​of the first three harmonic pulsations, i.e. q 1. q 2. q The value of 3 is used to obtain the instantaneous flow pulsation model of the hydraulic pump fluid.

[0036] When applying this method, the parameters set in the theoretical structural model of the gear pump include: throttle valve opening diameter, hydraulic medium temperature, density, bulk modulus, and viscosity based on measured pressure pulsations; constant signal module, sinusoidal signal module amplitude and frequency based on average flow rate; and pipe component diameter and length. For the piston pump, the parameters set in the theoretical structural model include: throttle valve opening diameter, hydraulic medium temperature, density, bulk modulus, and viscosity based on measured pressure pulsations; pipe component diameter and length; pump motor speed; and piston parameters.

[0037] The pump source pressure pulsation testing system includes a hydraulic pump under test (3), an electric 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). The inlet of the hydraulic pump under test (3) is connected to the outlet pipeline of the oil tank (14), and the outlet is connected to the relief valve (6) and the hydraulic pipeline (7). Near the outlet of the hydraulic pump under test (3), the pressure sensor (8), flow sensor (9), and temperature sensor (10) are sequentially installed on the hydraulic pipeline (7). Each of the three sensors has an A / D converter (15) installed at its data output terminal. The A / D converter performs analog-to-digital conversion on the sensor signals before inputting them to the data acquisition card (16). The A / D converter also filters and denoises the signals, improving signal accuracy; additionally, it amplifies the signal during conversion to ensure no information is lost. A pressure gauge 11 is installed at the outlet of hydraulic line 7, which is then connected to the inlet of throttle valve 12. The outlet of throttle valve 12 is connected to the inlet of filter 13, and the outlet of filter 13 is connected to the return line of oil tank 14. The frequency converter 5 can adjust the speed of the motor driving the tested hydraulic pump 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 tested pump, it can control the tested hydraulic pump to generate hydraulic oil with different pulsation frequencies. Pressure sensor 8, flow sensor 9, and temperature sensor 10 collect corresponding data of the hydraulic oil in real time. After analog-to-digital conversion by A / D converter 15, the data is collected using data acquisition card 16, and then stored and processed by signal processing system 17. The data signal output of the above pump source pressure pulsation test system is used as the input of the hydraulic pump simulation model system. The simulation results characterize the flow pulsation, such as... Figure 2 As shown.

[0038] like Figure 3 and Figure 4 As shown, the hydraulic pump simulation model system includes a gear pump simulation analysis module and a piston pump simulation analysis module. The modeling of both modules is based on the mapping concept of digital twin technology, and is modeled according to the actual hydraulic system under test. It can reflect the layout of the actual hydraulic system and the parameters can be set and modified according to the actual situation.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions 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 fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology, characterized in that: First, a theoretical structural model of the hydraulic pump (3) 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 rate at the outlet of the hydraulic pump (3) under test, and the density, bulk modulus, viscosity, and temperature of the hydraulic medium. Next, a pump source pressure pulsation test system (1) for the hydraulic pump (3) under test is constructed, including the hydraulic pump (3) under test, hydraulic pipelines (7) connected to each hydraulic component, pressure sensor (8), flow sensor (9), temperature sensor (10), pressure gauge (11), throttle valve (12), oil tank (14), A / D converter (15), data acquisition card (16), and signal processing system (17); the oil inlet of the hydraulic pump (3) under test is connected to the oil outlet pipeline of the oil tank (14), and the oil outlet is connected to the hydraulic pipeline (7); pressure sensor (8), flow sensor (9), and temperature sensor (10) are installed sequentially on the hydraulic pipeline (7) near the outlet of the hydraulic pump (3) under test, and the data output terminals of the three sensors are connected to the input terminals of the data acquisition card (16) after passing through an A / D converter (15); in the hydraulic... A pressure gauge (11) is installed at the outlet of the pressure pipeline (7), and then 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 by the pressure gauge (11). The pressure pulsation signal, average flow signal and hydraulic oil temperature signal of the fluid at the outlet of the hydraulic pump (3) under test are measured by the pressure sensor (8), flow sensor (9) and temperature sensor (10), respectively. Then, each signal is collected by the data acquisition card (16) after passing through the A / D converter (15). The collected signals are processed by the signal processing system (17) and used as input parameters of the theoretical structural model of the hydraulic pump (3) under test, including the measured temperature of the hydraulic medium, the pressure pulsation at the pump outlet, the average flow, and other input parameters are known quantities. Finally, the theoretical structural model of the hydraulic pump under test (3) is simulated and calculated by the hydraulic pump simulation model system (2) to approximately obtain 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 fluid obtained by simulation is the actual output flow pulsation of the hydraulic pump under test (3). At this time, the theoretical structural model parameters of the hydraulic pump under test (3) are the final determined parameters. The theoretical structural model of the hydraulic pump (3) under test is as follows: For the theoretical structural model of the gear pump, the average flow rate is fitted and modeled by superimposing the first three harmonic pulsation frequencies of the gear pump. Specifically, it is built by superimposing a constant signal module and three sinusoidal signals through a summation module. Then, the hydraulic flow transmitter module and the empty cavity module are connected to complete the overall modeling of the gear pump. The entire gear pump hydraulic system should also be connected to the 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 piston pump hydraulic system includes a piston model, a power model, and a load model. The piston model is composed of piston modules. The power model is composed of a motor module, a rotary spring module, and a rotary load module. The load model is simulated by a throttle valve (12) module, and the input of the throttle valve (12) module is determined by a constant signal module. Finally, the oil tank (14) is connected to complete the modeling of the piston pump hydraulic system. The signal processing system (17) extracts the average pressure 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 stores the extracted data. In practice, the first three order harmonic pulsations account for the main part. Therefore, the core of characterizing the instantaneous flow pulsation is to obtain the accurate amplitude of the first three order harmonic pulsation signals, i.e., the values ​​of q1, q2, and q3, and then obtain the instantaneous flow pulsation model of the hydraulic pump fluid. The parameters set in the theoretical structural model of the gear pump include: throttle valve opening diameter, hydraulic medium temperature, density, bulk modulus and viscosity set according to measured pressure pulsation; constant signal module, sine signal module amplitude and frequency set according to average flow rate; and pipe component diameter and length set. The parameters set in the theoretical structural model of the piston pump hydraulic system include: throttle valve opening diameter, hydraulic medium temperature, density, bulk modulus and viscosity set according to measured pressure pulsation; pipe component diameter and length set; and motor speed and piston parameters set according to the drive pump.

2. 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: In the pump source pressure pulsation test system (1), the hydraulic pump under test (3) and the hydraulic pipeline (7) connected to each hydraulic component are the hydraulic part of the system. The hydraulic pump under test (3) 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 connected to the pressure sensor (8), flow sensor (9), and temperature sensor (10) respectively to collect the actual working conditions of the measured hydraulic system, including the pressure pulsation signal, average flow signal and temperature signal of the hydraulic pump outlet fluid. The signal processing system (17) reads, processes, analyzes and stores the data collected by the data acquisition card (16) from each sensor. The reading includes reading the average flow rate 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 average pressure value in the time domain information of the pressure signal, the first three pressure amplitudes in the frequency domain information and the average flow rate value measured by the flow sensor (9), and storing the extracted data so as to set the parameters of the corresponding simulation model according to these data, which is convenient for subsequent simulation calculations.

3. The method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology according to claim 2, characterized in that: The oil outlet of the hydraulic pump (3) under test is connected to an overflow valve (6), which is used as a safety valve.

4. The method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology according to claim 3, characterized in that: The outlet of the throttle valve (12) is equipped with a filter (13), and the outlet of the filter (13) is connected to the return oil pipeline of the oil tank (14).

5. The method for characterizing the fluid flow pulsation characteristics of a hydraulic pump based on digital twin technology according to claim 4, characterized in that: The installation distance between the pressure sensor (8) and the oil outlet of the hydraulic pump (3) being tested is 20-30 mm; The flow sensor (9) and temperature sensor (10) are installed between the pressure sensor (8) and the pressure gauge (11).

6. 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 based on the actual arrangement of the pump source pressure pulsation test system (1), and models the system based on the instantaneous flow model of the hydraulic pump (3) under test. At the same time, it simulates the change of system pressure by adjusting the corresponding throttle valve (12). The oil parameters are set by actual oil parameters and data measured by the sensor. The length and diameter parameters of the pipeline components are set according to the actual measurement of the hydraulic components.

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