Method and system for monitoring behavior state of digital twin-driven numerical control machine tool

Abstract

The invention discloses a behavior state monitoring method and system for a digital twin-driven numerical control machine tool. The method comprises the following steps: establishing a digital twin model according to entity characteristics of a numerical control machine tool; performing packet capture analysis on the communication process according to the secondary development guidance manual of the numerical control machine tool to obtain numerical control machine tool data; mapping the twin model of the digital space according to the data of the numerical control machine tool, and integrating the data to an interface to form a visual twin system; and the visual twin system is in communication connection with the numerical control machine tool, and the behavior state of the numerical control machine tool is monitored. According to the method, behavior detection can be effectively performed on the machine tool through measures such as spatial model modeling, data acquisition, monitoring algorithm and interface development, periodic management is realized, and constraints such as time, space, cost and safety on a traditional numerical control machine tool are broken through. According to the method, data acquisition can be performed by using multiple languages, so that twinning of the numerical control machine tool can be realized on multiple platforms, and the method has universality.

Description

Technical Field

[0001] The present invention relates to a method for monitoring the behavior state of a numerically controlled machine tool in the technical field of industrial manufacturing, and particularly to a method for monitoring the behavior state of a numerically controlled machine tool driven by digital twin, and also relates to a system for monitoring the behavior state of a numerically controlled machine tool driven by digital twin. Background Technique

[0002] With the rapid development of modern manufacturing industry, numerically controlled machine tools, as important equipment for high-precision and high-efficiency machining, are widely used in fields such as aerospace, automobile manufacturing, and precision instruments. Due to the complex working conditions and diverse machining tasks faced by numerically controlled machine tools during operation, the accuracy and real-time performance of their state monitoring and behavior management are particularly important.

[0003] However, traditional numerically controlled machine tool monitoring methods are usually based on offline data analysis, which is difficult to meet the current high-precision, real-time, and intelligent monitoring requirements. At present, most of the data collection for numerically controlled machine tools is based on the secondary development API interface provided by the numerical control system. However, this method is restricted by a single language and is not convenient for expansion. When a numerically controlled machine tool is machining, parameters such as the position, speed, and current of each axis can only be observed in real time on-site through a traditional host computer. This is not only restricted by costs such as time and space, but also unable to save historical data, making the data analysis process after machining extremely difficult. Summary of the Invention

[0004] To solve the technical problem that the existing numerically controlled machine tool monitoring method can only monitor in real time and is easily restricted by multiple factors, the present invention provides a method and system for monitoring the behavior state of a numerically controlled machine tool driven by digital twin.

[0005] The present invention is implemented by the following technical solutions: A method for monitoring the behavior state of a numerically controlled machine tool driven by digital twin, which includes the following steps:

[0006] Establish a digital twin model according to the physical characteristics of the numerically controlled machine tool;

[0007] According to the secondary development guide manual of the numerically controlled machine tool, perform packet capture analysis on the communication process to obtain numerically controlled machine tool data;

[0008] Map the twin model in the digital space according to the numerically controlled machine tool data, and integrate the data into the interface to form a visual twin system;

[0009] Communicate and connect the visual twin system with the numerically controlled machine tool to monitor the behavior state of the numerically controlled machine tool.

[0010] The present invention realizes real-time perception, analysis, and optimization of the entire life cycle of equipment by establishing a virtual digital model of physical entities and combining real-time data interaction. Through measures such as spatial model modeling, data acquisition, monitoring algorithms, and interface development, it can effectively detect the behavior of machine tools, achieve periodic management, break through the constraints of time, space, cost, and safety imposed on traditional CNC machine tools, and solve the technical problem that existing CNC machine tool monitoring methods can only perform real-time monitoring and are vulnerable to multiple factor constraints. It can effectively break through the limitation that the communication interfaces provided by CNC systems are trapped by specific languages, so that data can be collected in multiple languages, making the construction of digital twins not limited by programming languages and laying a foundation for its application on multiple platforms.

[0011] As a further improvement of the above solution, the method for establishing the digital twin model includes the following steps:

[0012] First, parameterize and collect the entity features, then sequentially establish non-standardized parts based on the collected data, and finally import the standardized parts from the preset parameterized part library to initially establish a spatial model;

[0013] According to the assembly ownership relationship of each axis in the CNC machine tool entity, set the parent-child relationship between each axis and the transformation of the spatial coordinate system in the spatial model;

[0014] Perform mesh division on the cutting tools and parts in the spatial model, and perform rendering on the entire machine tool according to the collection of the color and material of the machine tool entity to maintain overall consistency, and finally obtain the digital twin model.

[0015] Furthermore, perform initial modeling through SoildWorks software, import gears and grinding wheels into the part library of SoildWorks software through preset standardized parameters, and perform rendering according to the physical machine tool;

[0016] First, draw a 3D model in SoildWorks software and export it, then open the exported file with 3ds max software for mesh division, and export it in fbx format;

[0017] Use unity software to develop the digital platform of the digital twin model, import the fbx file of the gear grinding machine into unity software, then use the built-in lighting and camera system of unity software to complete the construction of the environment, and finally complete the parent-child relationship of each axis by dragging.

[0018] As a further improvement of the above solution, the method for obtaining the CNC machine tool data includes the following steps:

[0019] Find the API for communicating with the CNC machine tool and the variable addresses provided by itself;

[0020] Use the Wireshark software to capture packets and analyze the captured content to query the specific communication protocol;

[0021] Record the original messages of the collected variables; the original messages include the format of the sent messages, the specific areas and specific unit addresses of the CNC machine tools to which the variables belong, the format of the messages replied by the machine tools, and the variable types;

[0022] Write a client for data collection to complete the data collection of CNC machine tools.

[0023] Furthermore, first, based on the secondary development communication interface API provided by the Sinumerik 840Dsl numerical control system, preliminarily collect the data of the CNC machine tools, and then use the hardware network analyzer and Wireshark software to capture messages during the communication process.

[0024] Still further, the generation method of the visual twin system includes the following steps:

[0025] Develop a monitoring algorithm: First, according to the specific data of each axis collected, scale the data by the spatial unit length, translate the starting point, and map it to the specific coordinates of each axis in the digital space. Then, use the lerp interpolation function to make the machine tool model in the digital space move smoothly. Finally, save the data collected during each machining process and write it to a local folder;

[0026] Develop a twin interface: Make corresponding charts for display according to the collected data including the position, speed, feed rate, and current magnitude of each axis;

[0027] Generate the visual twin system according to the monitoring algorithm and the twin interface.

[0028] Still further, when developing the monitoring algorithm, add the collected position data of each axis to each axis and perform spatial coordinate transformation between the absolute coordinate system and the relative coordinate system; when developing the twin interface, print the data and text to the interface through the UGUI component provided by the Unity software, set buttons, and place the visual chart on the interface through the xchart plugin.

[0029] As a further improvement of the above solution, add try catch exception capture code in the object-oriented programming language to check whether the visual twin system and the CNC machine tool communicate successfully, and compare the collected data with the data of the machine tool host computer to check the consistency of the communication.

[0030] Further, the numerical control machine tool is a YW7232CNC gear grinding machine tool; the numerical control machine tool includes a machine body, an electronic gearbox and nine numerical control axes, where six of the numerical control axes are respectively a grinding wheel head rotary shaft A1, a grinding wheel rotary shaft B1, a workbench rotary shaft C1, a grinding wheel radial feed shaft X1, a grinding wheel tangential feed shaft Y1, and a grinding wheel axial feed shaft Z1; the module m of the gear to be machined n1 = 4 mm, the number of teeth z1 = 35, the helix angle β1 = 30°, the normal pressure angle α n1 = 20°, the tooth width b n1 = 30 mm, the module m of the worm grinding wheel n2 = 4 mm, the number of starts z2 = 3, and the helix angle γ2 = 2.596°.

[0031] The present invention also provides a numerical control machine tool behavior state monitoring system driven by digital twin, which monitors the behavior state of the numerical control machine tool through any one of the above-mentioned digital twin-driven numerical control machine tool behavior state monitoring methods.

[0032] Compared with the existing numerical control machine tool monitoring methods and systems, the digital twin-driven numerical control machine tool behavior state monitoring method and system of the present invention have the following beneficial effects:

[0033] 1. The digital twin-driven numerical control machine tool behavior state monitoring method realizes real-time perception, analysis and optimization of the entire life cycle of the equipment by establishing a virtual digital model of the physical entity and combining real-time data interaction. Moreover, by capturing the message to write the corresponding client, data can be collected in multiple languages, enabling the digital twin of the numerical control machine tool to be realized on multiple platforms, making it universal.

[0034] 2. The digital twin-driven numerical control machine tool behavior state monitoring method can effectively detect the behavior of the machine tool through measures such as spatial model modeling, data collection, monitoring algorithm and interface development, achieving periodic management and breaking the constraints of traditional numerical control machine tools in terms of time, space, cost and safety.

[0035] 3. The digital twin-driven numerical control machine tool behavior state monitoring method can effectively break through the limitation that the communication interface provided by the numerical control system is trapped in a specific language, and thus data can be collected in multiple languages, making the construction of the digital twin not limited by the programming language and laying a foundation for its application on multiple platforms. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a flowchart of the digital twin-driven numerical control machine tool behavior state monitoring method according to Embodiment 1 of the present invention;

[0037] Figure 2 is Figure 1System framework diagram of the digital twin-driven numerical control machine tool behavior state monitoring method;

[0038] Figure 3 This is a comparison diagram of the machine tool structure before and after modeling and forming in Embodiment 1 of the present invention. Detailed implementation manners

[0039] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0040] Embodiment 1

[0041] Please refer to Figure 1 、 Figure 2 and Figure 3 This embodiment provides a digital twin-driven numerical control machine tool behavior state monitoring method. This monitoring method is used to monitor the behavior state of the numerical control machine tool, and can detect parameters such as the position, rotation speed, and current of each axis in real time. This method realizes the synchronous mapping of the physical machine tool and the virtual model by establishing a high-fidelity digital twin model and collecting the operation data of the machine tool in real time, and finally constructs a visual monitoring system. Among them, this method is particularly suitable for the real-time state monitoring of the YW7232CNC numerical control gear grinding machine, and mainly includes the following four steps.

[0042] Step 1: Establish a digital twin model according to the entity characteristics of the numerical control machine tool. In this embodiment, the method for establishing the digital twin model includes the following steps: (1) First, parameterize and collect the entity characteristics, then sequentially establish the non-standardized parts according to the collected data, and finally import the standardized parts from the preset parameterized part library for collection to initially establish a spatial model; (2) Set the parent-child relationship between the axes and the transformation of the spatial coordinate system in the spatial model according to the assembly ownership relationship of each axis in the numerical control machine tool entity; (3) Perform mesh division on the cutting tool and the part in the spatial model, and render the whole machine tool according to the collection of the color and material of the machine tool entity to maintain the overall consistency, and finally obtain the digital twin model.

[0043] In this embodiment, the numerical control machine tool is a YW7232CNC numerical control gear grinding machine, and includes a bed, an electronic gearbox, and nine numerical control axes. Among them, during the gear grinding process, six numerical control axes are mainly involved in the movement, namely the grinding wheel spindle rotation axis A1, the grinding wheel rotation axis B1, the workbench rotation axis C1, the grinding wheel radial feed axis X1, the grinding wheel tangential feed axis Y1, and the grinding wheel axial feed axis Z1. Collect the characteristic parameters of the above axes, and then use SoildWorks software for initial modeling. The modulus m of the gear to be machined n1= 4 mm, number of teeth z1 = 35, helix angle β1 = 30°, normal pressure angle α n1 = 20°, tooth width b n1 = 30 mm, module of worm grinding wheel m n2 = 4 mm, number of starts z2 = 3, helix angle of lead γ2 = 2.596°.

[0044] Import the gear and grinding wheel into the parts library of SoildWorks software through preset standardized parameters, and render according to the physical machine tool. In this embodiment, first draw a 3D model in SoildWorks software and export it to a Step format file, then open the exported file with 3ds max software for mesh division, and export it as an fbx format using the game mode. In this embodiment, unity software is used to develop the digital platform of the digital twin model. Import the fbx file of the gear grinding machine into unity software, and then use the built-in lighting and camera system of unity software to complete the construction of the environment for better observing the operating state of the machine tool. Finally, complete the parent-child relationship of each axis by dragging. As a real-time 3D engine, unity software has powerful rendering capabilities, can generate realistic 3D models and scenes at high frame rates, and supports multi-platform development (Windows, Linux, Android, iOS, WebGL, etc.), which is convenient for efficiently building models. Through the above process, the spatial modeling and preprocessing of the YW7232CNC gear grinding machine tool can be completed.

[0045] Step 2: According to the secondary development guide manual of the CNC machine tool, perform packet capture analysis on the communication process to obtain the CNC machine tool data. On the basis of secondary development, this embodiment performs packet capture analysis on the communication process to obtain the machine tool IP address, communication protocol, handshake rules, etc., and then writes the client to obtain the detailed machine tool data. In this embodiment, the method for obtaining CNC machine tool data includes the following steps: (1) According to the secondary development guide manual provided by the CNC system, find the API for communicating with the CNC machine tool and the variable addresses provided by itself to complete the preliminary acquisition of the machine tool data; (2) On the basis of the previous step, use wireshark software to capture the packets of the communication process between the machine tool and the local machine, and analyze the captured content to query the specific communication protocol; the communication protocol includes each handshake process between the two. If the protocol is implemented based on TCP / IP, the IP address of the machine tool needs to be noted; (3) Record the original packets of the collected variables; the original packets include the format of the sent packets, the specific area and specific unit address of the variables belonging to the CNC machine tool, the format of the packets replied by the machine tool, and the variable type; (4) Write the client for data acquisition to complete the acquisition of the CNC machine tool data.

[0046] The W7232 CNC gear grinding machine uses the sinumerik 840Dsl numerical control system. First, according to the secondary development communication interface API provided by the sinumerik 840Dsl numerical control system, the data of the CNC machine tool is initially collected, and then the hardware network analyzer and wireshark software are used to capture the messages during the communication process. It can be seen from the messages captured by the wireshark software during the communication process that the sinumerik 840Dsl numerical control system uses the S7 communication protocol based on TCP / IP, its IP address is 192.168.214.1, and the port number is 102. The second handshake is based on COTP, and its message is 0300004a45e00000000200c11c010601020102000005060500000000000000000000 00000000000400c21c01000002000000000000000000000000000000000000000000000d04c0010b. The third handshake is based on S7, and its message is 0300001902f08032010000000100080000f0000064006403c0. Through these three handshakes, communication can be established with the YW7232 CNC gear grinding machine.

[0047] Since unity uses the C# language for programming, a client for collecting data is written based on C#, and the messages of the three handshakes are sent to the PLC in sequence, and the content replied by the PLC three times can be received in sequence, compared with the obtained messages to check their consistency, and then normal communication can be established with the YW7232 CNC gear grinding machine.

[0048] For the acquisition of specific data, take the position information of the Y-axis as an example here. Find the message for obtaining the position information of the Y-axis in the captured messages, such as 0300001d02f08032010000000a000c0000040112088241001900027001. According to the parsing of the message by the wireshark software, the specific position where the Y-axis is located and the function of this piece of information can be found. Then find the corresponding replied message, such as 0300002102f08032030000000a0002000c00000401ff09000884640113b83b54c0, where 84640113b83b54c0 represents the specific position information of the Y-axis. Then compare it with the actual coordinates, and it is parsed as a 64-bit double-precision floating-point number, with the low-order bits first and the high-order bits later. Through this method, data such as the position information of other axes, rotational speed, and current can be obtained.

[0049] Through the above step, the problem that the communication interface provided by the numerical control system is restricted by a specific language can be effectively solved. Therefore, data can be collected in multiple languages, enabling the construction of digital twins to be independent of programming languages and laying a foundation for its application on multiple platforms.

[0050] Step 3: Map the twin model in the digital space according to the data of the numerically controlled machine tool and integrate the data into the interface to form a visual twin system. In this embodiment, the generation method of the visual twin system includes the following steps: (1) Develop a monitoring algorithm: First, scale the collected data of each axis by the unit length of space, translate the starting point, and map it to the specific coordinates of each axis in the digital space. Then, use the lerp interpolation function to make the machine tool model in the digital space move smoothly. Finally, save the data collected during each machining process and write it to a local folder to provide a theoretical basis for subsequent machining optimization. To improve the twin efficiency, multi-threaded methods can be used for data collection, simulation algorithms, interface design, etc., enabling multiple tasks to be executed simultaneously, making full use of the performance of multi-core processors and making the program run more efficiently. (2) Develop a twin interface: Make corresponding charts for display according to the collected data including the position, rotation speed, feed speed, and current magnitude of each axis. (3) Generate a visual twin system based on the monitoring algorithm and the twin interface. In addition, interface jump buttons, display of different machining methods, data collection switches, etc. can be added to enrich the overall twin function.

[0051] When developing the monitoring algorithm, add the collected position data of each axis to each axis and perform spatial coordinate transformation between the absolute coordinate system and the relative coordinate system. In this embodiment, spatial coordinate transformation is required. Since the machine tool has two coordinate systems during machining and non-machining, namely the absolute coordinate system and the relative coordinate system. Therefore, two coordinate transformation formulas need to be corresponding. Taking the transformation of the X-axis as an example, the transformation formula for the absolute coordinate system is x_virtual = 0.0010504776 * xPosition + 1.064256424, and the transformation formula for the relative coordinate system is x_virtual = 0.0009382089 * xPosition + 1.291235822, where x_virtual is the X-axis coordinate in the digital space, xPosition is the real X-axis coordinate, the coefficient is the spatial scaling ratio, and the intercept is the offset of the spatial coordinate origin.

[0052] After obtaining the position information of each axis, to make the model move smoothly and keep the state updated in real time, the lerp interpolation function can be used to apply the position, angle, etc. of each axis to Vector3.Lerp, Quaternion.Lerp, etc., and the behavior monitoring of the YW7232CNC gear grinding machine can be quickly realized.

[0053] In order to ensure the smooth operation of the digital twin platform and avoid congestion of the main thread, the Task multi-threading method can be used to efficiently manage asynchronous operations. The main thread can be responsible for updating the real-time motion of the model, UI interface chart information, etc., and the sub-thread can be responsible for data collection.

[0054] When developing the twin interface, the UGUI component that comes with the unity software is used to print data and text to the interface, and buttons are set, and visual charts are placed on the interface through the xchart plug-in. The UGUI component that comes with unity contains functions such as Canvas, Button, and Text, which can print data and text to the interface. The xchart plug-in can draw the current into a line chart on the interface for real-time monitoring.

[0055] Step 4: Connect the visual twin system to the CNC machine tool and monitor the behavior of the CNC machine tool. Add try catch exception capture code in the object-oriented programming language (C#) to check whether the visual twin system and the CNC machine tool are communicating successfully, and compare the collected data with the data of the machine tool host computer to verify the consistency of communication. Compare the behavior and movement of the machine tool in the digital space with the physical entity machine tool, as well as the interface data of the two, to ensure that the monitoring function can be accurately played.

[0056] Compared with the existing CNC machine tool monitoring method, the digital twin-driven CNC machine tool behavior status monitoring method of this embodiment has the following beneficial effects:

[0057] 1. The digital twin-driven CNC machine behavior status monitoring method realizes real-time perception, analysis and optimization of the entire life cycle of the equipment by establishing a virtual digital model of the physical entity and combining it with real-time data interaction. Moreover, by capturing messages and writing corresponding clients, data collection can be performed in multiple languages, so that the twin of the CNC machine tool can be implemented on multiple platforms, making it universal.

[0058] 2. The digital twin-driven CNC machine tool behavior status monitoring method can effectively detect the behavior of machine tools and achieve periodic management through measures such as spatial modeling, data collection, monitoring algorithms and interface development, breaking the time, space, cost and safety constraints of traditional CNC machine tools.

[0059] 3. The digital twin-driven CNC machine tool behavior status monitoring method can effectively break through the limitations of the communication interface provided by the CNC system that is trapped in a specific language, and can use multiple languages for data collection, so that the construction of digital twins will not be limited by programming languages, laying the foundation for its application on multiple platforms.

[0060] Example 2

[0061] This embodiment provides a numerical control machine tool behavior state monitoring system driven by digital twin. This system monitors the behavior state of the numerical control machine tool through the numerical control machine tool behavior state monitoring method in Embodiment 1. The system may include a model establishment module, a data acquisition module, a twin system generation module, and a verification and monitoring module. The model establishment module is used to establish a digital twin model according to the entity features of the numerical control machine tool. The data acquisition module is used to capture and analyze the communication process according to the secondary development guide manual of the numerical control machine tool to obtain numerical control machine tool data. The twin system generation module is used to map the twin model in the digital space according to the numerical control machine tool data and integrate the data into the interface to form a visual twin system. The verification and monitoring module is used to establish a communication connection between the visual twin system and the numerical control machine tool to monitor the behavior state of the numerical control machine tool. This system realizes the construction of the digital twin body of the numerical control machine tool, breaks through the constraints of time, space, cost, and safety on the related functions of the physical entity of the numerical control machine tool, and improves its application value.

[0062] Embodiment 3

[0063] This embodiment provides a computer terminal, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the numerical control machine tool behavior state monitoring method in Embodiment 1 are realized.

[0064] When the method of Embodiment 1 is applied, it can be applied in the form of software. For example, it can be designed as an independently running program and installed on a computer terminal. The computer terminal can be a computer, a smart phone, a control system, and other Internet of Things devices, etc. The method of Embodiment 1 can also be designed as an embedded running program and installed on a computer terminal, such as installed on a single-chip microcomputer.

[0065] Embodiment 4

[0066] This embodiment provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the steps of the numerical control machine tool behavior state monitoring method in Embodiment 1 are realized.

[0067] When the method of Embodiment 1 is applied, it can be applied in the form of software. For example, it can be designed as an independently running program on a computer-readable storage medium. The computer-readable storage medium can be a USB flash drive, designed as a USB key, and designed as a program that starts the whole method through external triggering through the USB flash drive.

[0068] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for monitoring the behavior state of a numerically controlled machine tool driven by digital twins, characterized in that, It includes the following steps: Establish a digital twin model according to the physical characteristics of the CNC machine tool; According to the secondary development guide manual of the CNC machine tool, perform packet capture analysis on the communication process to obtain CNC machine tool data; Map the twin model in the digital space according to the CNC machine tool data, and integrate the data into the interface to form a visual twin system; Communicate and connect the visual twin system with the CNC machine tool to monitor the behavior status of the CNC machine tool.

2. The digital twin-driven numerical control machine tool behavior state monitoring method according to claim 1, wherein The method for establishing the digital twin model includes the following steps: First, parameterize and collect the physical characteristics, then sequentially establish non-standard parts according to the collected data, and finally import the standard parts from the preset parameterized part library to initially establish a spatial model; Set the parent-child relationship between the axes and the transformation of the spatial coordinate system in the spatial model according to the assembly belonging relationship of each axis in the CNC machine tool entity; Perform mesh division on the cutting tool and parts in the spatial model, and render the overall machine tool according to the collection of the color and material of the machine tool entity to maintain overall consistency, and finally obtain the digital twin model.

3. The digital twin-driven numerical control machine tool behavior state monitoring method according to claim 2, wherein Perform initial modeling through SoildWorks software, import gears and grinding wheels into the part library of SoildWorks software through preset standard parameters, and render according to the physical machine tool; First, draw a 3D model in SoildWorks software and export it, then open the exported file with 3ds max software for mesh division, and export it in fbx format; Use unity software to develop the digital platform of the digital twin model, import the fbx file of the gear grinding machine into unity software, then use the built-in lighting camera system of unity software to complete the construction of the environment, and finally complete the parent-child relationship of each axis by dragging.

4. The digital twin-driven numerical control machine tool behavior state monitoring method according to claim 1, characterized in that, The method for obtaining the CNC machine tool data includes the following steps: Find the API for communicating with the CNC machine tool and the variable addresses provided by itself; Use wireshark software to perform packet capture and analyze the packet capture content to query the specific communication protocol; Record the original message of the collected variable; the original message includes the format of the sent message, the specific area and specific unit address of the variable belonging to the CNC machine tool, and the format and variable type of the message replied by the machine tool; Write a client for data collection to complete the collection of CNC machine tool data.

5. The digital-twin-driven numerical control machine tool behavior state monitoring method according to claim 4, characterized in that, First, perform preliminary collection of the data of the CNC machine tool according to the secondary development communication interface API provided by the sinumerik840Dsl numerical control system, and then use a hardware network analyzer and wireshark software to capture messages during the communication process.

6. The digital twin-driven numerical control machine tool behavior state monitoring method according to claim 2, characterized in that The method for generating the visual twin system includes the following steps: Develop monitoring algorithms: First, according to the specific data of each axis collected, scale the data by spatial unit length, translate the starting point, and correspond to the specific coordinates of each axis in the digital space. Then use the lerp interpolation function to make the machine tool model in the digital space move smoothly. Finally, save the data collected in each processing process and write it to a local folder. Develop twin interface: Make corresponding charts for display based on the collected data including the position, rotation speed, feed speed and current of each axis; The visual twin system is generated according to the monitoring algorithm and the twin interface.

7. The digital-twin-driven numerical control machine tool behavior state monitoring method according to claim 6, wherein When developing the monitoring algorithm, the collected position data of each axis is added to each axis, and the spatial coordinates of the absolute coordinate system and the relative coordinate system are transformed; when developing the twin interface, the data and text are printed to the interface through the UGUI component that comes with the unity software, and buttons are set, and visual charts are placed on the interface through the xchart plug-in.

8. The digital twin-driven numerical control machine tool behavior state monitoring method according to claim 1, characterized in that A try catch exception capture code is added to the object-oriented programming language to check whether the visual twin system and the CNC machine tool communicate successfully, and the collected data is compared with the data of the machine tool host computer to check the consistency of communication.

9. The digital twin-driven numerical control machine tool behavior state monitoring method according to claim 2, wherein, The numerically controlled machine tool is a YW7232CNC gear grinding machine tool; the numerically controlled machine tool includes a machine body, an electronic gearbox and nine numerically controlled axes, among which six numerically controlled axes are respectively a rotary shaft A1 of the grinding wheel headstock, a rotary shaft B1 of the grinding wheel, a rotary shaft C1 of the workbench, a radial feed axis X1 of the grinding wheel, a tangential feed axis Y1 of the grinding wheel, and an axial feed axis Z1 of the grinding wheel; the module m of the gear to be machined n1 = 4 mm, the number of teeth z1 = 35, the helix angle β1 = 30°, the normal pressure angle α n1 = 20°, the tooth width b n1 = 30 mm, the module m of the worm grinding wheel n2 = 4 mm, the number of heads z2 = 3, and the helix angle γ2 = 2.596°.

10. A digital twin-driven behavior state monitoring system for numerically controlled machine tools, characterized in that, It monitors the behavior state of the CNC machine tool by using the digital twin driven CNC machine tool behavior state monitoring method as described in any one of claims 1 to 9.

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