Method for constructing digital twin system of electro-hydrostatic actuator

Abstract

The invention discloses an electro-hydrostatic actuator digital twin system construction method, which comprises the following steps: according to the working principle and composition structure of an electro-hydrostatic actuator, constructing a multi-disciplinary simulation model of each component and system of the electro-hydrostatic actuator, and completing the development of a virtual prototype of the electro-hydrostatic actuator; building an electro-hydrostatic actuator physical prototype loading test platform, and completing the development of a driving and data acquisition system; data interconnection of the physical prototype and the virtual prototype of the electro-hydrostatic actuator is achieved, and building of the digital twin system of the electro-hydrostatic actuator is completed; based on an electro-hydrostatic actuator digital twinning system, visual panel development is completed, and a virtual-real interaction function of an electro-hydrostatic actuator is achieved through an operation panel. The digital twin technology is used for providing data support for the electro-hydrostatic actuator, an electro-hydrostatic actuator digital visualization platform is developed on the basis of a client-simulation side server-data acquisition side server three-layer structure, and the design of the electro-hydrostatic actuator with higher precision and lower operation difficulty is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of digitalization of mechatronic-hydraulic integrated products, and in particular to the technical field of a method for constructing a digital twin system of an electrostatic-hydraulic actuator. Background Art

[0002] Electro-Hydrostatic Actuator (EHA) is an integrated power electric actuator with highly integrated electrical, hydraulic and mechanical functions. It has the advantages of integration, flexible design, high power and stepless speed regulation, and has broad application prospects in aerospace and shipbuilding. Benefiting from the continuous progress of high-power servo technology, digital signal processing technology and electromagnetic technology, electro-hydrostatic actuators are in a rapid development stage of engineering prototype development and test flight.

[0003] Digital twin is a technology that maps physical entities to virtual entities in a digital way, deeply integrating the information of physical entities and virtual entities. The virtual entity can truly depict the properties and behaviors of the physical entity and realize the dynamic interaction between virtual and reality. The country has proposed to build digital workshops and smart factories around key equipment fields such as machinery, automobiles, aviation, aerospace, ships, weapons, electronics, and electricity, and to build a digital twin system for the entire life cycle of equipment. Therefore, the hydraulic field also needs to continuously upgrade and develop in the direction of digitalization and intelligence.

[0004] With the development of more electric aircraft, the progress of various aircraft components towards electrification is changing with each passing day, which puts forward development requirements for the dynamic performance, power density, energy efficiency and reliability of airborne actuation systems. At present, the application of electrostatic hydraulic actuator integrated design in China is still in its infancy, so it is urgent to strengthen research in this field. Empowering the integrated design of electrostatic hydraulic actuators with digital twins has become the only way for the aviation industry to promote digital transformation and cultivate a new cross-border integration ecosystem. Summary of the invention

[0005] The purpose of the present invention is to solve the problems in the prior art and to propose a method for constructing a digital twin system of an electrostatic-hydraulic actuator, aiming to use digital twin technology to provide data support for the electrostatic-hydraulic actuator and to achieve the design of an electrostatic-hydraulic actuator with higher precision and lower operating difficulty.

[0006] To achieve the above object, the present invention proposes a method for constructing a digital twin system of an electrostatic hydraulic actuator, comprising the following steps: Step 1: According to the working principle and composition structure of the electrostatic hydraulic actuator, build a multidisciplinary simulation model of the components and system of the electrostatic hydraulic actuator to complete the development of the virtual prototype of the electrostatic hydraulic actuator.

[0007] Step 2: Build a physical prototype loading test platform for the electrostatic hydraulic actuator and complete the development of the drive and data acquisition system.

[0008] Step 3: Realize the data interconnection between the physical prototype and the virtual prototype of the electrostatic-hydraulic actuator to complete the construction of the digital twin system of the electrostatic-hydraulic actuator.

[0009] Step 4: Based on the digital twin system of the electrostatic-hydraulic actuator, complete the development of the visualization panel, and use the operation panel to visualize the virtual and real data of the electrostatic-hydraulic actuator.

[0010] The electrostatic hydraulic actuator digital twin system of the present invention comprises: The physical prototype module is the physical basis of the digital twin system of the electrostatic-hydraulic actuator.

[0011] The virtual prototype module realizes the mapping of the physical prototype of the electrostatic-hydraulic actuator in the virtual space and is the simulation basis for the digital twin system of the electrostatic-hydraulic actuator.

[0012] The twin data measurement module is used to measure the consistency of physical prototype data and virtual prototype data.

[0013] The digital platform provides a visual operation panel for the electrostatic hydraulic actuator digital twin system.

[0014] The electrostatic hydraulic actuator physical prototype module of the present invention includes a sensor configuration, a loading test platform, and a drive and data acquisition system: 1) Complete the sensor configuration design of the physical prototype of the electrostatic hydraulic actuator to provide actual operation data for the digital twin system of the electrostatic hydraulic actuator; 2) Complete the design of the electrostatic hydraulic actuator loading test platform to simulate various working conditions and test the physical prototype of the electrostatic hydraulic actuator; 3) Complete the design of the physical prototype drive and data acquisition system of the electrostatic hydraulic actuator, and realize the closed-loop control and data acquisition of the electrostatic hydraulic actuator.

[0015] In the electrostatic hydraulic actuator physical prototype module 1), the electrostatic hydraulic actuator physical prototype adopts a limited sensing configuration of position-speed-current-pressure.

[0016] In the electrostatic hydraulic actuator physical prototype module 2), the electrostatic hydraulic actuator physical prototype adopts a top cylinder loading method to perform load simulation.

[0017] The electrostatic hydraulic actuator virtual prototype module of the present invention comprises: The multidisciplinary simulation model of the electrostatic-hydraulic actuator is integrated, covering the multidisciplinary characteristics of the electrostatic-hydraulic actuator, including hydraulics, control, mechanics and thermodynamics. It can not only reflect the geometric parameters and material properties of each component itself, but also combine the various characteristics of the electrostatic-hydraulic actuator with the actual data of the physical prototype to achieve real-time and high-precision virtual-reality mapping.

[0018] The multidisciplinary simulation model integration solution is an algorithm based on the FMI standard and model order reduction fusion: for one-dimensional simulation models, first use the deep neural network algorithm to achieve order reduction, and then use the FMI standard (functional mock-up interface) to export the reduced model as an FMU file (Functional Mock-up Unit); for multidimensional simulation models, first use the intrinsic orthogonal decomposition algorithm fused with radial basis interpolation to achieve order reduction, and then export the model grid file and node data file; after processing, the multidisciplinary simulation model can run independently of the simulation software, and interact through data flow to form a complete set of electrostatic hydraulic actuator virtual prototypes.

[0019] The twin data measurement module of the electrostatic hydraulic actuator of the present invention uses the root mean square error to judge the physical prototype data acquisition data and virtual prototype calculation data The degree of timing consistency is expressed as follows: , in, , are the upper and lower limits of the acceptable root mean square error; This means that the data of both have completely passed the consistency assessment and there is no need to modify the virtual prototype of the electrostatic hydraulic actuator; It means that there is a certain error in the twin data, and the PID parameters of the position loop of the virtual prototype of the electrostatic hydraulic actuator need to be corrected until the evaluation status is , to realize the modification of the virtual prototype of the electrostatic hydraulic actuator; It indicates that the accuracy of the electrostatic hydraulic actuator virtual prototype is poor, and it is necessary to re-identify the parameters of the electrostatic hydraulic actuator prototype itself and complete the high-fidelity reconstruction of the electrostatic hydraulic actuator multidisciplinary model so that the evaluation status can at least reach .

[0020] The twin data measurement module of the electrostatic hydraulic actuator of the present invention is used to evaluate the status A method for online adjustment of the position loop PI parameters integrating fuzzy rules is proposed. Different from the traditional fuzzy PID controller, this method takes the actual displacement of the EHA physical prototype as the expected output and adjusts the virtual prototype position loop PI parameters until its evaluation state is improved to .

[0021] The electrostatic hydraulic actuator digital platform of the present invention comprises: 1) Client: The digital twin visualization operation panel of the electrostatic hydraulic actuator, including the input parameter module and the optimization result output module; 2) Simulation-side server, which completes the virtual prototype computing service of the electrostatic hydraulic actuator; 3) The data acquisition side server completes the data processing related to the physical prototype of the digital twin system of the electrostatic hydraulic actuator.

[0022] In the electrostatic hydraulic actuator digital platform 1), the client input parameter module includes the electrostatic hydraulic actuator system operating parameters and the value range of each component design parameter, and the optimization result output module includes the structure and property parameters of each key component, as well as the dynamic response curve and actual power density value of the electrostatic hydraulic actuator system after optimization; In the electrostatic hydraulic actuator digital platform 2), the simulation side server provides algorithm interfaces such as FMU files and reduced-order models, completes the deployment and loading of the virtual prototype according to the electrostatic hydraulic actuator multidisciplinary model integration solution, and realizes the real-time calculation of the virtual prototype simulation results through the physical prototype data transmitted by the data acquisition side server, providing data support for the design of the electrostatic hydraulic actuator; In the electrostatic hydraulic actuator digital platform 3), the data acquisition side server is responsible for managing, collecting and storing a series of data generated by the virtual prototype and the physical prototype during operation, and transmitting the physical prototype data acquisition data to the client after processing, while interacting with the simulation side server to provide input operating parameters for the virtual prototype.

[0023] Beneficial effects of the present invention: 1. The present invention proposes a digital twin system architecture for the entire electrostatic hydraulic actuator.

[0024] 2. The present invention proposes a multidisciplinary simulation model integration solution for electrostatic hydraulic actuators based on FMI standards and model reduction fusion, realizing multidisciplinary coupling calculation of virtual prototypes.

[0025] 3. In the design of the digital twin system of the electrostatic-hydraulic actuator, the present invention adds a twin data measurement module and proposes a data consistency measurement index, which can correct the accuracy of the virtual prototype of the electrostatic-hydraulic actuator more efficiently and clearly.

[0026] 4. The present invention provides a visual operation panel for the electrostatic hydraulic actuator system, reducing the difficulty for operators to get started.

[0027] The features and advantages of the present invention will be described in detail through embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1It is a schematic diagram of the system architecture of a method for constructing a digital twin system of an electrostatic hydraulic actuator according to the present invention; Figure 2 It is a schematic diagram of a multidisciplinary model integration scheme of a virtual prototype of an electrostatic hydraulic actuator in a method for constructing a digital twin system of an electrostatic hydraulic actuator according to the present invention; Figure 3 It is a schematic diagram of an online precision correction scheme of a virtual prototype of an electrostatic hydraulic actuator in a method for constructing a digital twin system of an electrostatic hydraulic actuator according to the present invention; Figure 4 The present invention Figure 1 A partial enlargement of the figure. DETAILED DESCRIPTION

[0029] Working process of the present invention: The present invention uses digital twin technology to enable the integrated design of electrostatic-hydraulic actuators, designs a digital twin system architecture of electrostatic-hydraulic actuators, develops a digital twin visualization platform for electrostatic-hydraulic actuators based on a three-layer structure of client-simulation side server-data acquisition side server, and uses digital twin technology to provide data support for electrostatic-hydraulic actuators to achieve integrated design of electrostatic-hydraulic actuators with higher precision and lower operating difficulty.

[0030] like Figure 1 As shown, the electrostatic-hydraulic actuator digital twin system of the present invention includes a physical prototype module, which is the physical basis of the electrostatic-hydraulic actuator digital twin system; a virtual prototype module, which realizes the mapping of the physical prototype of the electrostatic-hydraulic actuator in the virtual space, and is the simulation basis of the electrostatic-hydraulic actuator digital twin system; a twin data measurement module, which is used to measure the consistency of the physical prototype data and the virtual prototype data; a digital platform, which realizes the visualization of the electrostatic-hydraulic actuator digital twin system and provides an operation panel for the virtual-reality interaction of the electrostatic-hydraulic actuator digital twin.

[0031] The actual operating input parameters are injected into the physical prototype of the electrostatic-hydraulic actuator, and the operating parameters are passed to the virtual prototype of the electrostatic-hydraulic actuator integrated by a multidisciplinary model for calculation. The physical prototype data is transmitted to the twin data measurement module through sensors, and a consistency evaluation is performed with the calculation results of the virtual prototype. The accuracy of the virtual prototype is corrected. After passing the consistency evaluation, the digital data of the physical prototype of the electrostatic-hydraulic actuator and the calculation data of the virtual prototype are transmitted to the digital platform to provide data support for system integration optimization design.

[0032] The electrostatic hydraulic actuator physical prototype module described in the present invention includes a sensing configuration, a loading test platform, and a drive and data acquisition system. The electrostatic hydraulic actuator physical prototype adopts a limited sensing configuration of position-speed-current-pressure to provide actual operating data for the electrostatic hydraulic actuator digital twin system; the electrostatic hydraulic actuator loading test platform design can simulate a variety of working conditions to test the electrostatic hydraulic actuator physical prototype, and adopts a top cylinder loading method to simulate the load; the electrostatic hydraulic actuator physical prototype drive and data acquisition system design realizes the closed-loop control and data acquisition of the electrostatic hydraulic actuator.

[0033] The electrostatic-hydraulic actuator virtual prototype module described in the present invention integrates the multidisciplinary simulation model of the electrostatic-hydraulic actuator, covering the multidisciplinary characteristics of the electrostatic-hydraulic actuator, including the fields of hydraulics, control, mechanics and thermodynamics. It can not only reflect the geometric parameters and material properties of each component itself, but also combine the various characteristics of the electrostatic-hydraulic actuator with the actual data of the physical prototype to achieve real-time and high-precision virtual-real mapping.

[0034] Figure 2 The figure shows an integrated solution for the multidisciplinary simulation model of electrostatic-hydraulic actuators based on the FMI standard and model order reduction fusion: for one-dimensional simulation models, the deep neural network algorithm is first used to achieve order reduction, and then the FMI standard is used to export the reduced-order model as an FMU file; for multidimensional simulation models, the intrinsic orthogonal decomposition algorithm fused with radial basis interpolation is first used to achieve order reduction, and then the model grid file and node data file are exported; after processing, the multidisciplinary simulation model can run independently of the simulation software, and interact through data flow to form a complete set of virtual prototypes of electrostatic-hydraulic actuators.

[0035] The essence of simulation using commercial software is to use mathematical methods to establish a physical model of the research object and solve complex numerical equations. The accuracy of the solution determines the accuracy of the simulation, which is often time-consuming and cannot meet real-time requirements. Therefore, it is necessary to use a large amount of existing simulation data and a reduced-order model method to achieve real-time calculation of the digital twin of the electrostatic hydraulic actuator.

[0036] The one-dimensional simulation model is relatively simple. Through the neural network algorithm in machine learning, a nonlinear mapping model between input parameters and output parameters can be established, and the weight parameters of each node can be continuously iterated until the accuracy requirements are met. Taking the EHA hydraulic system as an example, the one-dimensional model reduction method is analyzed and divided into the following five steps.

[0037] Step 1: Input parameter selection. The input of the electrostatic hydraulic actuator is displacement and external load instructions. When the research object does not change, only the influence of displacement and load force on the simulation results needs to be considered. Therefore, these two signals are selected as the input of the reduced-order model.

[0038] Step 2: Dataset construction. Taking the simulated displacement of the electrostatic hydraulic actuator as an example, according to the EHA joint simulation model, the full working conditions of displacement amplitude 1-40mm, frequency 0.1-5Hz and load force amplitude 0-120KN are analyzed, and the data set of input signal and simulated displacement signal is constructed, which is divided into training set and parameter set in a ratio of 4:1.

[0039] Step 3: Neural network construction. Build a neural network model with 2 inputs, 3 intermediate layers and 1 output.

[0040] Step 4: Reduced-order model training. Using mean square error (MSE) as the loss function evaluation standard, the parameters of each node of the neural network are calculated until convergence, completing the model training.

[0041] Step 5: Model export: Export the reduced-order model as an FMU file based on the FMI standard.

[0042] The multi-dimensional simulation model built for research objects such as electromagnetics, thermal fields, and flow fields has output parameters as grid node data. The data volume is large and complex. The simulation data can be intrinsically orthogonal decomposed, and the output grid node data under any working condition can be calculated through radial basis interpolation. The multi-dimensional simulation results can be visualized with the grid model. The specific process can be divided into the following 4 steps.

[0043] Step 1: Snapshot matrix construction. For multi-dimensional simulation objects such as the flow field and thermal field of electrostatic hydraulic actuators, extract m node data on the research object, including parameters such as pressure, flow and temperature. This data set is the snapshot. Combine the data under n working conditions to construct the snapshot matrix shown in the following formula.

[0044] , in, is the j-th node data under the i-th group of working conditions.

[0045] Step 2: Singular value (SVD) decomposition. Use SVD decomposition on the snapshot matrix, select the first k-order singular values ​​whose sum of contributions is greater than 90%, and extract the first k-order POD basis from the left singular value matrix. Once the POD basis is selected, the basis coefficients have a unique solution.

[0046] Step 3: Solve the basis coefficients. Define the working condition space distance as the L2 norm of any working condition parameter and the given working condition parameter, use the Gaussian kernel function to perform radial basis interpolation on the basis coefficients, and the final solution function is: ,in, Extract the first k-order POD basis of the left singular matrix to form a new matrix. Any working condition parameter With given working condition parameters The L2 norm of is the Gaussian kernel function.

[0047] Step 4: Rendering of simulation results. VTK is an object-oriented visualization toolkit based on OpenGL that supports parallel processing and cross-platform. It can transform data into graphics using data streams, so it is widely used in computer graphics and image processing.

[0048] The twin data measurement module of the electrostatic hydraulic actuator of the present invention uses the root mean square error to judge the physical prototype data acquisition data and virtual prototype calculation data The degree of timing consistency is expressed as follows: , in, , are the upper and lower limits of the acceptable root mean square error; This means that the data of both have completely passed the consistency assessment and there is no need to modify the virtual prototype of the electrostatic hydraulic actuator; It means that there is a certain error in the twin data, and the PID parameters of the position loop of the virtual prototype of the electrostatic hydraulic actuator need to be corrected until the evaluation status is , to realize the modification of the virtual prototype of the electrostatic hydraulic actuator; It indicates that the accuracy of the electrostatic hydraulic actuator virtual prototype is poor, and it is necessary to re-identify the parameters of the electrostatic hydraulic actuator prototype itself and complete the high-fidelity reconstruction of the electrostatic hydraulic actuator multidisciplinary model so that the evaluation status can at least reach .

[0049] For evaluation status , a method for online adjustment of the position loop PI parameters integrating fuzzy rules is proposed. Different from the traditional fuzzy PID controller, this method takes the actual displacement of the EHA physical prototype as the expected output and adjusts the virtual prototype position loop PI parameters until its evaluation state is improved to The specific steps are as follows: Step 1: Fuzzy set definition. The input of the fuzzy controller is the error of virtual and real displacement data, as well as the error change rate. The output is the change of position loop parameters. Three fuzzy subsets are set in the fuzzification: positive large, zero value and negative large.

[0050] Step 2: Establish fuzzy rules. Select the triangle membership function and set the domain of each parameter. The domain range will change under different working conditions.

[0051] Step 3: Position loop PI parameter adjustment. Calculate the error and change rate of the virtual and real displacement data transmitted to the twin data module in real time, adjust the virtual prototype position loop PI parameters online according to the fuzzy rules, and output the updated displacement data.

[0052] Step 4: Status evaluation. Take a full stroke actuation cycle as the time window, and the window gradually moves forward as the data points are input. Perform consistency status evaluation on the virtual and real data in the window. If the evaluation status is still , repeat steps 3-4.

[0053] The electrostatic-hydraulic actuator digital platform structure described in the present invention includes a client, which is a digital twin visualization operation panel of the electrostatic-hydraulic actuator, including an input parameter module and an optimization result output module; a simulation side server, which completes the electrostatic-hydraulic actuator virtual prototype calculation service; and a data acquisition side server, which completes the data processing related to the physical prototype of the digital twin system of the electrostatic-hydraulic actuator.

[0054] In the digital platform client of the electrostatic-hydraulic actuator of the present invention, the input parameter module includes the operating parameters of the electrostatic-hydraulic actuator system and the value range of the design parameters of each component, and the optimization result output module includes the structure and property parameters of each key component, as well as the dynamic response curve and actual power density value of the electrostatic-hydraulic actuator system after optimization; in the simulation side server, the simulation side server provides FMU files, reduced-order models and integrated optimization design algorithm interfaces, completes the deployment and loading of the virtual prototype according to the multidisciplinary model integration solution of the electrostatic-hydraulic actuator, and realizes the real-time calculation of the virtual prototype simulation results through the physical prototype data transmitted by the data acquisition side server, providing data support for the integrated optimization design of the electrostatic-hydraulic actuator; in the data acquisition side server, the data acquisition side server is responsible for managing, collecting and storing a series of data generated by the virtual prototype and the physical prototype during operation, and transmits the physical prototype data acquisition data to the client after processing, and interacts with the simulation side server at the same time to provide input operating parameters for the virtual prototype.

[0055] The visual operation panel of the electrostatic hydraulic actuator digital twin system described in the present invention is built based on the Flask framework, where the left side is the parameter input module, including the electrostatic hydraulic actuator system operating parameters and the value range of each component design parameter, and the right side is the optimization result output module, including the structure and attribute parameters of each key component, as well as the dynamic response curve and power density of the electrostatic hydraulic actuator after optimization. The specific integrated design algorithm is deployed in the simulation side server of the electrostatic hydraulic actuator digital platform.

[0056] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention belongs to the protection scope of the present invention.

Claims

1. A method for constructing a digital twin system of an electrostatic hydraulic actuator, characterized in that: The steps include: Step 1: According to the working principle and composition structure of the electrostatic hydraulic actuator, build a multidisciplinary simulation model of the components and system of the electrostatic hydraulic actuator to complete the development of the virtual prototype of the electrostatic hydraulic actuator; the development method of the virtual prototype is to build it based on the multidisciplinary simulation model integration solution of FMI standard and model order reduction fusion. For the one-dimensional simulation model, first use the deep neural network algorithm to achieve order reduction, and then use the FMI standard to export the reduced model as an FMU file; For multi-dimensional simulation models, the intrinsic orthogonal decomposition algorithm integrated with radial basis interpolation is first used to achieve order reduction, and then the model grid file and node data file are exported. After processing, the multi-disciplinary simulation model can run independently of the simulation software and interact through data flow to form a complete set of electrostatic hydraulic actuator virtual prototype; Step 2: Build a physical prototype loading test platform for the electrostatic hydraulic actuator and complete the development of the drive and data acquisition system; Step 3: Realize the data interconnection between the physical prototype and the virtual prototype of the electrostatic hydraulic actuator, and complete the construction of the digital twin system of the electrostatic hydraulic actuator; Step 4: Based on the digital twin system of the electrostatic-hydraulic actuator, complete the development of the visualization panel, and use the operation panel to realize the virtual-reality interaction function of the electrostatic-hydraulic actuator.

2. The method for constructing a digital twin system of an electrostatic hydraulic actuator according to claim 1, characterized in that: The electrostatic hydraulic actuator digital twin system includes a physical prototype module, a virtual prototype module, a twin data measurement module and a digital platform; The physical prototype module is the physical basis of the digital twin system of the electrostatic-hydraulic actuator; the virtual prototype module realizes the mapping of the physical prototype of the electrostatic-hydraulic actuator in the virtual space, and the virtual prototype module is the simulation basis of the digital twin system of the electrostatic-hydraulic actuator; the twin data measurement module is used to measure the consistency of the physical prototype data and the virtual prototype data; the digital platform realizes the visualization of the digital twin system of the electrostatic-hydraulic actuator, and the digital platform provides a visual operation panel for the digital twin of the electrostatic-hydraulic actuator.

3. The method for constructing a digital twin system of an electrostatic hydraulic actuator according to claim 1, characterized in that: The physical prototype module in step 2 includes a sensor configuration, a loading test platform, and a drive and data acquisition system. The steps of building the physical prototype module include: Step 2.1: Complete the sensor configuration design of the physical prototype of the electrostatic hydraulic actuator to provide actual operation data for the digital twin system of the electrostatic hydraulic actuator; Step 2.2: Complete the design of the electrostatic hydraulic actuator loading test platform to simulate various working conditions and test the physical prototype of the electrostatic hydraulic actuator; Step 2.3: Complete the design of the physical prototype drive and data acquisition system of the electrostatic hydraulic actuator to realize closed-loop control and data acquisition of the electrostatic hydraulic actuator.

4. The method for constructing a digital twin system of an electrostatic hydraulic actuator according to claim 2, characterized in that: The twin data measurement module uses the root mean square error to judge the physical prototype data acquisition data and virtual prototype calculation data The degree of timing consistency is expressed as follows: in , are the upper and lower limits of the acceptable RMS error, This means that the data of both parties have completely passed the consistency assessment. It means that there are certain errors in the twin data. It indicates that the virtual prototype of the electrostatic hydraulic actuator has poor accuracy. represents the root mean square error.

5. The method for constructing a digital twin system of an electrostatic hydraulic actuator according to claim 4, characterized in that: The evaluation results are When the twin data measurement module uses the position loop PI parameter online adjustment method integrating fuzzy rules to correct the accuracy of the virtual prototype of the electrostatic hydraulic actuator online until the evaluation result is improved to , the specific steps are: Step s1: Fuzzy set definition: The input of the fuzzy controller is the error of the virtual and real displacement data, as well as the error change rate, and the output is the change of the position loop parameter. Three fuzzy subsets of positive, zero and negative are set in the fuzzification; Step s2: Establish fuzzy rules: Select the triangle membership function and set the domain of each parameter. The domain range will change under different working conditions. The triangle membership function used is defined as follows: ； Step s3: Position loop PI parameter adjustment: Calculate the error and change rate of the virtual and real displacement data transmitted to the twin data module in real time, adjust the virtual prototype position loop PI parameters online according to the fuzzy rules, and output the updated displacement data; Step s4: Status evaluation: Take a full stroke actuation cycle as the time window, and the window gradually moves forward as the data points are input. The consistency status of the virtual and real data in the window is evaluated. If the evaluation status is still , then repeat steps s3-s4.

6. The method for constructing a digital twin system of an electrostatic hydraulic actuator according to claim 2, characterized in that: The digital platform includes a client, a simulation side server and a data acquisition side server; the client is a digital twin visualization operation panel of the electrostatic hydraulic actuator, and the client includes an input parameter module and an optimization result output module; the simulation side server is used to complete the computing service of the virtual prototype of the electrostatic hydraulic actuator; the data acquisition side server is used to complete the relevant data processing of the physical prototype of the electrostatic hydraulic actuator.

7. The method for constructing a digital twin system of an electrostatic hydraulic actuator according to claim 6, characterized in that: The input parameter module of the client includes the operating parameters of the electrostatic-hydraulic actuator system and the value range of the design parameters of each component; the optimization result output module of the client includes the structure and property parameters of each key component, as well as the dynamic response curve and actual power density value of the electrostatic-hydraulic actuator system after optimization; the simulation side server is used to provide FMU files, reduced-order models and integrated optimization design algorithm interfaces, complete the deployment and loading of the virtual prototype according to the multidisciplinary model integration solution of the electrostatic-hydraulic actuator, and realize the real-time calculation of the virtual prototype simulation results through the physical prototype data transmitted by the data acquisition side server, so as to provide data support for the integrated optimization design of the electrostatic-hydraulic actuator; the data acquisition side server is responsible for managing, collecting and storing a series of data generated by the virtual prototype and the physical prototype during operation, and transmitting the physical prototype data acquisition data to the client after processing, and interacting with the simulation side server to provide input operating parameters for the virtual prototype.

8. The method for constructing a digital twin system of an electrostatic hydraulic actuator according to claim 3, characterized in that: In the step 2.1, the physical prototype adopts a limited sensing configuration of position-speed-current-pressure; in the step 2.2, the physical prototype adopts a top cylinder loading method to perform load simulation.

9. The method for constructing a digital twin system of an electrostatic hydraulic actuator according to claim 1, characterized in that: The specific construction method of the one-dimensional simulation model of the electrostatic hydraulic actuator is as follows: Step 1.11: Input parameter selection: The input of the electrostatic hydraulic actuator is displacement and external load instructions; Step 1.12: Dataset construction: Analyze all working conditions with displacement amplitude of 1-40mm, frequency of 0.1-5Hz and load amplitude of 0-120KN, construct a data set of input signal and simulation displacement signal, and divide it into training set and parameter set in a ratio of 4:1; Step 1.13: Neural network construction: Build a neural network model with 2 inputs, 3 intermediate layers and 1 output; Step 1.14: Reduced-order model training: Using mean square error (MSE) as the loss function evaluation standard, the parameters of each node of the neural network are calculated until convergence, completing the model training; Step 1.15: Model export: Export the reduced-order model as an FMU file based on the FMI standard.

10. The method for constructing a digital twin system of an electrostatic hydraulic actuator according to claim 1, characterized in that: The specific construction method of the multi-dimensional simulation model of the electrostatic hydraulic actuator is: Step 1.21: Snapshot matrix construction: extract m node data on the research object as a data set, which is a snapshot. Combine the data under n working conditions to construct a snapshot matrix as shown in the following formula; Step 1.22: Singular value (SVD) decomposition: Use SVD decomposition on the snapshot matrix, select the first k-order singular values ​​whose sum of contributions is greater than 90%, and extract the first k-order POD basis from the left singular value matrix; when the POD basis is selected, the basis coefficient has a unique solution; Step 1.23: Solving the basis coefficients: define the working condition space distance as the L2 norm between any working condition parameter and the given working condition parameter, and use the Gaussian kernel function to perform radial basis interpolation on the basis coefficients; Step 1.24: Rendering of simulation results.

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