Joint simulation method for motion state of workbench of numerical control machine tool and control system

Abstract

The invention discloses a joint simulation method for a motion state of a numerical control machine tool workbench and a control system. The method comprises the steps that S1, a three-dimensional model of the numerical control machine tool workbench is created, and material attributes and constraint relations are set through Adams; s2, configuring a contact force and a driving relation in the three-dimensional model through Adams; s3, setting a state variable connecting the Adams and the Matlab, and associating the state variable with the motion state parameters to construct a joint simulation model; s4, loading the joint simulation model through Matlab, and calling Simulink to establish a workbench control system; s5, adjusting control parameters of a workbench control system by taking the moving speed of the workbench as a control target; and S6, running the joint simulation model and judging whether the numerical control machine tool workbench moves stably or not, if yes, ending joint simulation, and if not, returning to S5. The joint simulation method disclosed by the invention solves the problem of low reliability of the design of the workbench of the numerical control machine tool.

Description

Technical Field

[0001] The present invention relates to the technical field of numerically controlled machine tools, and in particular to a method for jointly simulating the motion state and control system of a numerically controlled machine tool workbench. Background Art

[0002] At present, the design and debugging of traditional precision machine tool workbenches follow a relatively fixed and inefficient process, mainly relying on theoretical mechanics formulas and experience accumulated from past designs to plan the mechanical structure and control system layout of the machine tool workbench, such as static strength analysis and three-dimensional motion simulation analysis, or experimental verification and analysis of the actual product in the early stage of product production. It is difficult to accurately predict and optimize the motion performance and control effect of the CNC machine tool workbench by only conducting mechanical structure mechanics analysis in the design stage. The cycle of physical verification analysis in the product stage is relatively long, and it only analyzes the structural performance of the product, and it is also impossible to accurately analyze the motion performance and corresponding control effect, resulting in low reliability of the CNC machine tool workbench. Summary of the invention

[0003] The main purpose of the present invention is to provide a joint simulation method of the motion state and control system of a CNC machine tool worktable, so as to at least solve the problem of low reliability of the CNC machine tool worktable caused by only performing motion state or structural performance analysis on the CNC machine tool worktable.

[0004] According to one aspect of the present invention, a method for jointly simulating the motion state and control system of a CNC machine tool worktable is provided, comprising:

[0005] Step S1: creating a three-dimensional model of a CNC machine tool workbench and setting material properties and constraint relationships of the three-dimensional model through Adams;

[0006] Step S2: configuring the contact force and driving relationship of the CNC machine tool worktable in the three-dimensional model by Adams;

[0007] Step S3: setting state variables for connecting Adams and Matlab and associating the state variables with the motion state parameters of the CNC machine tool worktable, and constructing a joint simulation model based on the motion state parameters;

[0008] Step S4: loading the joint simulation model through Matlab and calling Simulink to establish a CNC machine tool workbench control system based on PID control strategy;

[0009] Step S5: taking the moving speed of the CNC machine tool worktable as the control target, adjusting the control parameters of the CNC machine tool worktable control system;

[0010] Step S6: Run the joint simulation model and determine whether the CNC machine tool worktable moves smoothly according to the output of the CNC machine tool worktable control system. If yes, the joint simulation ends; otherwise, return to execute step S5.

[0011] Furthermore, the step S1 comprises:

[0012] Step S11: constructing a three-dimensional model of the CNC machine tool workbench through three-dimensional modeling according to the assembly relationship between the various components of the CNC machine tool workbench;

[0013] Step S12: Analyze the spatial relationship between the components, perform interference check on the 3D model through 3D modeling software, and determine whether there are overlapping components. If yes, execute step S11, otherwise execute step S13;

[0014] Step S13: saving the three-dimensional model of the CNC machine tool workbench as a Parasolid (*.x_t) format file;

[0015] Step S14: creating a new model in Adams, and importing the Parasolid (*.x_t) format file into the new model;

[0016] Step S15: Setting the material properties and constraint relationships of the imported three-dimensional model through Adams.

[0017] Furthermore, the step S15 includes:

[0018] Step S151: defining material properties between components in the three-dimensional model in Adams;

[0019] Step S152: Based on the material properties of different components, the material properties, mass properties and center of mass position of each component are solved by Adams;

[0020] Step S153: establishing the constraint relationship between the components of the three-dimensional model through Adams, wherein the constraint relationship includes a fixed pair, a rotation pair and a helical pair.

[0021] Furthermore, the step S2 comprises:

[0022] Step S21: setting contact forces between contacting parts in the three-dimensional model by Adams, wherein the contact forces include contact forces between the workbench and the pressure plate, contact forces between the workbench and the machine tool bed, contact forces between the slider and the machine tool bed, and contact forces between the slider and the pressure plate;

[0023] Step S22: creating a driving pulley and setting geometric parameters of the driving pulley through the Machinery module of Adams;

[0024] Step S23: creating a driven pulley in the Machinery module and setting the geometric parameters of the driven pulley according to the geometric parameters of the driving pulley;

[0025] Step S24: setting a constraint relationship and a position relationship between the driving pulley and the driven pulley, and connecting them to corresponding components;

[0026] Step S25: creating a belt with the driving pulley and the driven pulley as connection objects through the Machinery module and setting properties of the belt, wherein the properties include at least length, width and elastic modulus;

[0027] Step S26: establishing a driving function for the driving pulley, wherein the driving function includes a speed-time driving function.

[0028] Furthermore, the step S3 comprises:

[0029] Step S31: creating state variables for connecting to the Matlab interface through Adams;

[0030] Step S32: establishing state variable associations between the driving pulley driving speed of the CNC machine tool worktable, the worktable center of mass displacement, the worktable center of mass speed, and the worktable center of mass acceleration and the state variables respectively;

[0031] Step S33: Combine the state variables with associated relationships and establish a joint simulation model through the Controls module of Adams.

[0032] Furthermore, the step S33 includes:

[0033] Step S331: using the active pulley driving speed state variable as an input signal, and using the workbench center of mass displacement state variable, the workbench center of mass speed state variable, and the workbench center of mass acceleration state variable as output signals to construct a joint simulation model with Matlab as the target software;

[0034] Step S332: setting the analysis type of the joint simulation model to nonlinear and the solver type to C++, and generating a .m format file corresponding to the joint simulation model.

[0035] Furthermore, the step S4 comprises:

[0036] Step S41: running the .m format file through Matlab to load the model parameters of the joint simulation model;

[0037] Step S42: input the interface command "adams_sys" in the command line of Matlab, and display the module window of the interface command adams_sys;

[0038] Step S43: Import the adams_sub module in the adams_sys module window into the Simulink window newly created in Matlab and configure the joint simulation parameters;

[0039] Step S44: constructing a CNC machine tool workbench control system in the Simulink window based on the PID control strategy.

[0040] Furthermore, the step S5 comprises:

[0041] Step S51: setting the proportional coefficient, integral coefficient and differential coefficient of the PID controller corresponding to the PID control strategy;

[0042] Step S52: running the joint simulation model, and outputting a workbench mass center displacement signal, a workbench mass center velocity signal and a mass center acceleration signal to the CNC machine tool workbench control system in real time during the running of the joint simulation model;

[0043] Step S53: using the workbench mass center displacement signal, the workbench mass center velocity signal and the workbench mass center acceleration signal, the CNC machine tool workbench control system calculates the active pulley adjustment speed based on the designed CNC machine tool workbench control system PID controller;

[0044] Step S54: combining the PID adjustment speed with the rated speed of the driving pulley, and adjusting the proportional coefficient, the integral coefficient and the differential coefficient by analyzing the performance index of the CNC machine tool worktable.

[0045] Furthermore, the step S6 comprises:

[0046] Step S61: setting a plurality of simulation operation speeds of the CNC machine tool worktable, and determining a rated rotation speed of a driving pulley of the CNC machine tool worktable at the plurality of simulation operation speeds;

[0047] Step S62: the time required for the driving pulley to accelerate from rest to the rated speed under the plurality of simulation running speeds is set to be the same;

[0048] Step S63: when the driving pulley is accelerated to the rated speed, the moving speed of the CNC machine tool worktable is controlled by a PID controller so that the moving speed converges to the simulation running speed;

[0049] Step S64: Analyze the moving speed of the CNC machine tool worktable under the control of the PID controller to determine whether the CNC machine tool worktable runs smoothly. If so, the joint simulation ends, otherwise return to execute step S5.

[0050] Furthermore, the step S64 includes:

[0051] Step S641: obtaining the moving speed of the CNC machine tool worktable at different time nodes, and respectively calculating the speed deviation between the moving speed of the worktable at different time nodes and the simulation running speed;

[0052] Step S642: Determine whether the speed deviation at different time nodes is less than a preset speed deviation threshold. If so, it is determined that the CNC machine tool workbench is running smoothly and the joint simulation ends. Simultaneously, if otherwise, it is determined that the CNC machine tool workbench is running unsteadily, return to execute step S5 until the CNC machine tool workbench is running smoothly.

[0053] In the present invention, by using Adams and Matlab / Simulink to jointly simulate the CNC machine tool workbench in the design stage, the motion state and control effect of the CNC machine tool workbench under different working conditions can be simulated, avoiding the cumbersome process of repeatedly making physical prototypes for testing in the traditional method, and can greatly shorten the product development cycle. At the same time, the material, equipment loss and manpower investment required for the physical test are reduced, effectively reducing the R&D cost of the CNC machine tool. By building a control system in Simulink and associating it with the joint simulation model in Adams based on state variables, the real motion state of the CNC machine tool workbench can be simulated, thereby realizing more accurate control of the machine tool workbench motion based on the simulated motion state. By creating a three-dimensional model and setting material properties, constraint relationships, and configuring contact forces and drive relationships through Adams, the real physical properties of the CNC machine tool workbench can be fully restored, no longer limited to static strength and simple three-dimensional motion simulation, so that the three-dimensional model is closer to the actual working conditions. By associating state variables to build a joint simulation model, the link between Adams and Matlab is realized. Matlab is used to load the model and Simulink is used to build a CNC machine tool workbench control system based on the PID control strategy, which realizes the deep integration of the control system and the physical model, simulates the control effect in real time, and accurately predicts the motion performance in advance. The use of a PID-based control system can make the workbench movement speed more stable and close to the target speed, improving the reliability of the CNC machine tool workbench design. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0055] Figure 1 A schematic flow chart of a method for jointly simulating the motion state and control system of a CNC machine tool worktable disclosed in an embodiment of the present invention;

[0056] Figure 2 An exploded view of a three-dimensional model of a CNC machine tool workbench disclosed in an embodiment of the present invention;

[0057] Figure 3 It is a schematic diagram of the structure of the pulley transmission drive disclosed in the embodiment of the present invention;

[0058] Figure 4 A schematic diagram of a model of a CNC machine tool workbench control system disclosed in an embodiment of the present invention;

[0059] Figure 5 This is a control effect diagram of a CNC machine tool workbench disclosed in an embodiment of the present invention.

[0060] The above drawings include the following reference numerals:

[0061] 1. Workbench; 2. Pressure plate; 3. Bearing seat; 4. Spindle; 5. Ball nut; 6. Slider; 7. First connecting plate; 8. Cover plate; 9. Second connecting plate; 10. Third connecting plate; 11. Motor; 12. Coupling; 13. Synchronous pulley; 14. Bed; 15. Belt. DETAILED DESCRIPTION

[0062] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0063] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0064] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0065] See also Figure 1 As shown, according to an embodiment of the present application, a method for jointly simulating the motion state and control system of a CNC machine tool worktable is provided, comprising:

[0066] Step S1: Create a three-dimensional model of the CNC machine tool workbench and set the material properties and constraint relationships of the three-dimensional model through Adams;

[0067] Further, step S1 includes:

[0068] Step S11: constructing a three-dimensional model of the CNC machine tool workbench through three-dimensional modeling according to the assembly relationship between the various components of the CNC machine tool workbench;

[0069] Step S12: Analyze the spatial relationship between the components, perform interference check on the 3D model through 3D modeling software, and determine whether there are overlapping components. If so, execute step S11, otherwise execute step S13;

[0070] Step S13: saving the three-dimensional model of the CNC machine tool workbench as a Parasolid (*.x_t) format file;

[0071] Step S14: Create a new model in Adams and import the Parasolid (*.x_t) format file into the new model;

[0072] Step S15: Setting the material properties and constraint relationships of the imported three-dimensional model through Adams.

[0073] Further, step S15 includes:

[0074] Step S151: defining the material properties of the components in the three-dimensional model in Adams;

[0075] Step S152: Based on the material properties of different components, the material properties, mass properties and center of mass position of each component are solved by Adams;

[0076] Step S153: Establish constraint relationships between components of the three-dimensional model through Adams, where the constraint relationships include fixed pairs, rotational pairs, and helical pairs.

[0077] In the above embodiment, three-dimensional modeling is performed according to the actual assembly relationship of each component of the CNC machine tool workbench, and an accurate three-dimensional model is constructed, which truly restores the physical structure and lays a solid foundation for subsequent analysis and optimization. Using three-dimensional modeling software for interference inspection can detect possible spatial overlap problems between components in advance, avoid design defects, ensure the rationality and assemblability of the model, effectively reduce rework caused by design errors during physical assembly, and greatly save time and cost. The model is saved in Parasolid (*.x_t) format and imported into Adams software, which can make the simulation results more reliable. Define material properties in Adams, solve the material properties, mass properties and center of mass position of components based on material science theory, so that the physical parameters of the virtual model are highly consistent with the actual, and the simulation results are more realistic and reliable. Establish constraint relationships such as fixed pairs, revolute pairs and helical pairs, accurately simulate the actual connection and movement mode between components, whether it is mechanical transmission in a static state or coordinated cooperation during movement, it can be displayed truthfully, thereby realizing high-precision simulation of the workbench movement, helping R&D personnel to determine design risks in advance and optimize them.

[0078] Specifically, this embodiment uses SolidWorks to build a three-dimensional model of a CNC machine tool workbench. First, the following is established in SolidWorks: Figure 2The three-dimensional model of the CNC machine tool workbench shown in the figure includes a workbench 1, a pressure plate 2, a bearing seat 3, a spindle 4, a ball nut 5, a slider 6, a first connecting plate 7, a cover plate 8, a second connecting plate 9, a third connecting plate 10, a motor 11, a coupling 12, a synchronous pulley 13, and a bed 14. After obtaining the three-dimensional model of the CNC machine tool workbench, assemble it in the Solidworks software and perform interference check on the CNC machine tool workbench assembly. The specific process of interference check is: in the Solidworks software interface, click the "Interference Check" command button to start the interference check tool. In the interference check dialog box that pops up, take the entire CNC machine tool worktable assembly as the inspection object, that is, check all components including worktable 1, pressure plate 2, bearing seat 3, spindle 4, ball nut 5, slider 6, first connecting plate 7, cover plate 8, second connecting plate 9, third connecting plate 10, motor 11, coupling 12, synchronous pulley 13, and bed 14, to ensure that no components that need to participate in the interference check are missed. According to actual needs, set relevant inspection parameters, choose whether to treat the subassembly as a single entity for inspection, and set parameters such as the display accuracy of the interference volume. Click the "Calculate" button (the same name may vary depending on the version) to start the interference check of the selected assembly and automatically analyze whether there is spatial interference between the components. After the inspection is completed, all detected interferences will be displayed in the result list area of ​​the interference check dialog box. The list will show the names of the interfering parts, the number of interferences, and the approximate volume of interference, so as to facilitate a preliminary understanding of the distribution of interference problems.

[0079] After the interference check is complete, save the 3D model of the CNC machine tool workbench created in Solidworks as a Parasolid (*.x_t) format file, run the Adams software, and click "File and Import" in sequence to import the created 3D model. After importing the 3D model of the CNC machine tool workbench, set the material properties of each component of the 3D model of the CNC machine tool workbench in Adams. Adams automatically solves the material properties, mass properties, and center of mass position of each component based on the material properties of different components. Then, the constraint relationship between each component is established in Adams in turn. The constraint relationship includes fixed pair, rotation pair and helical pair. The specific process of establishing the preset relationship includes: establishing a fixed pair to connect the machine tool bed with the first connecting plate 7; establishing a fixed pair to connect the first connecting plate 7, the second connecting plate 9, the third connecting plate 10, the cover plate 8 and the motor 11 in sequence; establishing a fixed pair to connect the motor spindle with the lower synchronous pulley; establishing a fixed pair to connect each coupling 12 with the synchronous pulley; establishing a fixed pair to connect the machine tool spindle with the coupling 12; establishing a rotation pair to connect the two bearing seats 3 with the machine tool spindle; establishing a fixed pair to connect the two bearing seats with the machine tool bed; establishing a helical pair to connect the ball nut 5 with the spindle 14; establishing a fixed pair to connect the ball nut 5 with the bed 13; establishing a fixed pair to connect the six pressure plates 2 with the machine tool; establishing a fixed pair to connect the two sliders 6 with the machine tool.

[0080] Step S2: configuring the contact force and driving relationship of the CNC machine tool table in the three-dimensional model through Adams;

[0081] Further, step S2 includes:

[0082] Step S21: setting the contact force between the contacting parts in the three-dimensional model through Adams, the contact force includes the contact force between the workbench and the pressure plate, the contact force between the workbench and the machine tool bed, the contact force between the slider and the machine tool bed, and the contact force between the slider and the pressure plate;

[0083] Step S22: Create a driving pulley and set the geometric parameters of the driving pulley through the Machinery module of Adams;

[0084] Step S23: creating a driven pulley in the Machinery module and setting the geometric parameters of the driven pulley according to the geometric parameters of the driving pulley;

[0085] Step S24: setting the constraint relationship and position relationship between the driving pulley and the driven pulley, and connecting them to corresponding components;

[0086] Step S25: creating a belt with a driving pulley and a driven pulley as connection objects through the Machinery module and setting the properties of the belt, the properties including at least length, width and elastic modulus;

[0087] Step S26: establishing a driving function for the driving pulley, wherein the driving function includes a speed-time driving function.

[0088] In the above embodiment, by creating and finely setting the geometric parameters of the driving pulley and the driven pulley in the Machinery module, the physical form of the pulley is accurately restored according to the actual mechanical design specifications, so that the model can simulate the real pulley transmission structure with high accuracy. Reasonably set the constraints and positional relationship between the two, and connect them to the corresponding components to ensure that the power transmission process conforms to the actual working conditions and effectively avoid motion distortion caused by improper connection. Create a belt and set its properties such as length, width and elastic modulus, fully consider the actual characteristics of the belt such as elastic deformation and tension change in transmission, can truly reflect the mechanical behavior, and greatly improve the accuracy of the dynamic simulation of the pulley transmission system. Configure the speed-time driving function to simulate the actual speed change under motor drive.

[0089] Specifically, after setting the material properties and constraint relationships of the three-dimensional model, the contact forces between the components in the three-dimensional model include the contact forces between the workbench and the platen, the contact forces between the workbench and the machine tool bed, the contact forces between the slider and the machine tool bed, and the contact forces between the slider and the contacting platen. The process of establishing the contact force between the workbench and the platen is as follows: in the model tree of the Adams software, select the workbench and the corresponding six platen components in turn, and enter the contact force definition interface through the "Contact" module of the Adams software or the relevant contact force definition command entry. According to the contact relationship between each workbench and each platen, set the contact parameters. For example, define the contact type, set the contact stiffness coefficient (estimated according to the material properties and structural dimensions of the components), the contact damping coefficient (used to simulate the energy dissipation during the contact process), and determine the contact penetration depth threshold and other parameters. Repeat the above steps to accurately establish a contact force relationship that conforms to the actual physical properties between the workbench and each platen. The process of establishing the contact force between the workbench and the machine tool bed is as follows: select the two components of the workbench and the machine tool bed, enter the contact force definition interface, and set the contact force related parameters according to the material. The process of establishing the contact force between the slider and the machine tool bed is as follows: after selecting the corresponding slider and machine tool bed components, enter the contact force definition interface, consider the actual working conditions of the slider sliding on the bed, and combine the material properties, surface roughness and other factors of the slider and bed to set the appropriate contact stiffness. The contact stiffness reflects the supporting role of the slider when it contacts the bed, and can also reflect the elastic deformation; at the same time, set a suitable damping coefficient to simulate the friction energy consumption during the sliding process, etc., and establish contact force between each slider and the machine tool bed. The process of establishing the contact force between the slider and the pressure plate is as follows: select the corresponding slider and pressure plate components one by one, enter the contact force definition interface, and set the contact force parameters according to the contact form and material properties of the slider and the pressure plate in the actual structure. For example, the contact stiffness is determined based on the hardness and contact area of ​​the two, and the contact damping is assigned considering the energy loss characteristics during the contact process, thereby completing the contact force definition.

[0090] After completing the definition of the contact force, further define the drive. First, enter the Machinery module in the Adams software and find the function entry for defining the pulley drive in the Machinery module. Select the driving pulley component in the synchronous pulley and add a rotation drive to it. According to the preset motion parameters, set the function type of the drive, the specific drive parameter values, the start time and end time of the drive, etc., to simulate the actual situation in which the motor provides power to the synchronous pulley through the pulley transmission. In the AdamsMachinery module, use the belt connection tool to select the driving pulley and the driven pulley components, and create a belt to connect them according to the actual pulley layout and transmission path. Set the relevant parameters for the belt connection, such as the elastic modulus, preload, damping coefficient and other parameters of the belt, so that the belt connection can truly reflect the mechanical and motion transfer characteristics in the actual pulley transmission, such as Figure 3 The figure shows a schematic diagram of the structure of a pulley drive, wherein a belt 15 is sleeved on the synchronous pulleys of the driving pulley and the driven pulley to realize the transmission of the driving pulley and the driven pulley.

[0091] Step S3: setting state variables for connecting Adams and Matlab and associating the state variables with the motion state parameters of the CNC machine tool worktable, and building a joint simulation model based on the motion state parameters;

[0092] Further, step S3 includes:

[0093] Step S31: creating state variables for connecting to the Matlab interface through Adams;

[0094] Step S32: establishing state variable associations between the driving pulley driving speed of the CNC machine tool worktable, the worktable center of mass displacement, the worktable center of mass speed and the worktable center of mass acceleration and the state variables respectively;

[0095] Step S33: Combine the state variables with associated relationships and establish a joint simulation model through the Controls module of Adams.

[0096] Further, step S33 includes:

[0097] Step S331: using the active pulley driving speed state variable as the input signal, and using the workbench center of mass displacement state variable, the workbench center of mass speed state variable, and the workbench center of mass acceleration state variable as the output signal to construct a joint simulation model with Matlab as the target software;

[0098] Step S332: Set the analysis type of the joint simulation model to nonlinear, the solver type to C++, and generate a .m format file corresponding to the joint simulation model.

[0099] In the above embodiment, the state variables connected to the Matlab interface are created through Adams to achieve seamless data intercommunication. The key active pulley driving speed of the workbench, the displacement of the workbench center of mass, the speed of the workbench center of mass, and the acceleration of the workbench center of mass are accurately associated with the corresponding state variables, so that the abstract physical parameters can be accurately captured and efficiently used in the joint simulation environment. When the joint simulation model is constructed using the Controls module of Adams, the active pulley driving speed state variable is used as input, and the state variables related to the center of mass of the workbench are used as output. The joint simulation model is built for Matlab, which can synchronize the motion state simulation results of the CNC machine tool workbench to Matlab to further build the control system, thereby improving the reliability of the joint simulation.

[0100] Specifically, after completing the contact force and drive definition, select the "Model" menu in the Adams software interface, click the "StateVariables" command option, and the state variable creation dialog box pops up. Click the "New" button in the dialog box to create a new state variable and name it "for example, L1". Select the created state variable and connect it with the driving pulley drive speed in Adams through the association function provided by Adams software. Specifically, select the corresponding synchronous belt drive component in the association interface and specify its speed attribute as the actual physical quantity of the connection to ensure that the state variable can obtain the value of the driving pulley drive speed in real time. Use the "New" button in the "StateVariables" dialog box again to create three new state variables in succession and name them respectively: "L2", "L3", and "L4". For the variable "L2", find the center of mass position of the workbench through the center of mass analysis function of Adams software, and then use the association function to connect the variable with the displacement of the center of mass of the workbench in the direction of the corresponding coordinate axis, so that it can reflect the center of mass displacement in real time. According to similar operation methods, the variable "L3" is connected to the velocity vector of the workbench mass center, and the variable "L4" is connected to the acceleration vector of the workbench mass center, so that these three state variables can accurately obtain the values ​​of the corresponding physical quantities related to the workbench mass center. In the Adams software, switch to the "Adams / Controls" module. In the interface of the "Adams / Controls" module, click the "PlantExport" (model output) command button to pop up the joint simulation model creation dialog box. In the dialog box, select "InputChannel" (input channel) and specify the previously created state variable "L1" representing the driving speed of the active pulley as the input signal, indicating that the value of this variable will be transferred from the external control software (Matlab) to the Adams model to drive the movement of the virtual prototype. Select "OutputChannel" (output channel) and set the three state variables "L2", "L3", and "L4" representing the displacement, velocity, and acceleration of the workbench mass center as output signals in turn. The values ​​of these variables will be transmitted from the Adams model to the external control software (Matlab). Select "Matlab" in the "Target Software" drop-down menu to set the external control software for joint simulation to Matlab. For "Analysis Type", select the "Nonlinear" option to consider the nonlinear mechanics and motion characteristics that may exist in the actual operation of the virtual prototype, so that the simulation results are closer to the real situation.Select "C++" in the "SolverType" drop-down menu to use its efficient and stable solving performance to perform the joint simulation calculation process. Finally, click the "OK" button, and Adams will automatically generate four types of files: .m, .cmd, .adm, and .txt based on the above settings. Among them, the .m file usually contains control scripts that interact with Matlab, the .cmd file is used to control the startup and operation of the Adams model, the .adm file is the description file of the Adams model itself, and the .txt file contains relevant parameter descriptions or log information.

[0101] Step S4: Load the joint simulation model through Matlab and call Simulink to establish a CNC machine tool workbench control system based on PID control strategy;

[0102] Further, step S4 includes:

[0103] Step S41: Run the .m format file through Matlab to load the model parameters of the joint simulation model;

[0104] Step S42: input the interface command adams_sys in the command line of Matlab, and display the module window of the interface command adams_sys;

[0105] Step S43: Import the adams_sub module in the adams_sys module window into the Simulink window newly created in Matlab and configure the joint simulation parameters;

[0106] Step S44: Construct a CNC machine tool workbench control system in the Simulink window based on the PID control strategy.

[0107] In the above embodiment, Matlab is used to load the joint simulation model and call Simulink. Matlab runs the .m file to load the model parameters to ensure the accurate setting of the initial state of the model. Input the interface command adams_sys in the command line to call out the module window, import the key modules into the newly created Simulink window and configure the joint simulation parameters, so that the collaborative work of each part is more stable and efficient. The CNC machine tool workbench control system is constructed based on the PID control strategy. PID control, with its advantages of good dynamic response, high-precision control and strong adaptability to changes in system parameters, allows the CNC machine tool workbench control system to track the target quickly and accurately, greatly improving the control accuracy and stability of the system, and can effectively reduce errors and improve overall work efficiency.

[0108] refer to Figure 4Schematic diagram of the control system for the CNC machine tool workbench. Run the .m format file in the Matlab command window. The code is responsible for loading various parameters of the joint simulation model, including: mechanical structure parameters converted from the Adams model, previously defined state variable information, and settings related to the joint simulation interaction. After the loading is completed and there are no abnormalities, enter the interface command "adams_sys" in the Matlab command line. At this time, the system will automatically search and open the Simulink graphical CNC machine tool workbench joint simulation interface according to the pre-set settings. Create a new Simulink model window, copy the "adams_sub" module and output module in the opened "adams_sys" module window to the new Simulink window, and then modify the joint simulation parameters in the "adams_sub" module, set the simulation model to discrete, and set the sampling time to 0.001s. Design a PID controller in the Simulink window, connect it to the "adams_sub" module according to the control system signal flow logic, use the current moving speed signal of the workbench as the input of the PID controller, and set the rated working speed of the workbench as the control target of the PID control strategy.

[0109] Step S5: adjusting the control parameters of the CNC machine tool worktable control system with the moving speed of the CNC machine tool worktable as the control target;

[0110] Further, step S5 includes:

[0111] Step S51: setting the proportional coefficient, integral coefficient and differential coefficient of the PID controller corresponding to the PID control strategy;

[0112] Step S52: running the joint simulation model, and during the running of the joint simulation model, outputting the workbench center of mass displacement signal, the workbench center of mass velocity signal and the workbench center of mass acceleration signal to the CNC machine tool workbench control system in real time;

[0113] Step S53: using the workbench mass center displacement signal, the workbench mass center velocity signal and the workbench mass center acceleration signal, the PID controller of the CNC machine tool workbench control system calculates the active pulley adjustment speed;

[0114] Step S54: combining the PID adjustment speed with the rated speed of the driving pulley, and adjusting the proportional coefficient, the integral coefficient and the differential coefficient by analyzing the performance index of the CNC machine tool worktable.

[0115] It can be understood that in addition to the PID algorithm, this embodiment can also adopt cutting-edge control algorithms such as nonlinear control algorithms, fuzzy control algorithms, and intelligent control algorithms.

[0116] In the above embodiment, by continuously adjusting and optimizing the proportional coefficient, integral coefficient and differential coefficient, accurate control of the workbench moving speed can be achieved, which not only improves the stability of control, but also significantly improves the response speed and precision. By running the joint simulation model, the workbench center of mass displacement signal, the workbench center of mass velocity signal and the workbench center of mass acceleration signal can be output to the CNC machine tool workbench control system in real time, providing accurate data support, so that the control system can more accurately judge the current state, so that the PID adjustment speed can be effectively output, so that the workbench moving speed is further close to the target speed. This dynamic adjustment process ensures the continuous stability and accuracy of the workbench moving speed. By calculating the performance index and adjusting the parameters of the PID controller accordingly, the continuous optimization of the CNC machine tool workbench control system is achieved. This closed-loop adjustment mechanism not only improves the flexibility of control, but also ensures the stability and adaptability of the system under different working conditions.

[0117] Step S6: Run the joint simulation model and determine whether the CNC machine tool worktable moves smoothly based on the output of the CNC machine tool worktable control system. If yes, the joint simulation ends; otherwise, return to execute step S5.

[0118] Further, step S6 includes:

[0119] Step S61: setting a plurality of simulation operation speeds of the CNC machine tool worktable, and determining the rated rotation speed of the driving pulley of the CNC machine tool worktable at the plurality of simulation operation speeds;

[0120] Step S62: The time required for the driving pulley to accelerate from a stationary state to a rated speed under multiple simulation running speeds is set to be the same;

[0121] Step S63: When the driving pulley is accelerated to the rated speed, the moving speed of the CNC machine tool worktable is controlled by the PID controller so that the moving speed converges to the simulation running speed;

[0122] Step S64: Analyze the moving speed of the CNC machine tool worktable under the control of the PID controller to determine whether the CNC machine tool worktable runs smoothly. If so, the joint simulation ends, otherwise return to execute step S5.

[0123] Further, step S64 includes:

[0124] Step S641: obtaining the moving speed of the CNC machine tool worktable at different time nodes, and respectively calculating the speed deviation between the moving speed at different time nodes and the simulation running speed;

[0125] Step S642: Determine whether the speed deviation at different time nodes is less than a preset speed deviation threshold. If so, it is determined that the CNC machine tool workbench is running smoothly and the joint simulation ends. Simultaneously, if otherwise, it is determined that the CNC machine tool workbench is running unsteadily, and return to execute step S5 until the CNC machine tool workbench is running smoothly.

[0126] In the above embodiment, by presetting multiple simulation running speeds and corresponding rated speeds, various working conditions that may be encountered in the actual working environment are simulated, providing a comprehensive data basis for subsequent stability judgment. By setting the same acceleration time, the acceleration process of the active pulley at different speeds is ensured to be consistent, which facilitates the subsequent control and adjustment of the moving speed. The PID controller is used to control the moving speed of the CNC machine tool workbench in real time, so that it can converge to the simulation running speed quickly and accurately, effectively improving the accuracy and stability of the control. By calculating the speed deviation at different time nodes and comparing it with the preset speed deviation threshold, the running stability of the CNC machine tool workbench can be accurately judged. Once it is found that the operation is not stable, immediately return to execute the adjustment step until a stable state is reached, thereby ensuring the processing quality and efficiency of the machine tool.

[0127] Specifically, the working speed of the workbench is set to 10mm / s, 20mm / s, 30mm / s and 40mm / s. According to the pitch diameter of the driving pulley and the established transmission ratio, the rated speed of the synchronous pulley corresponding to each simulation running speed is calculated through the mechanical transmission formula. The ramp function module is introduced, and its starting value is set to 0, representing the initial static state of the driving pulley; the end value is accurately set according to the corresponding rated speed calculated in the previous step; the acceleration time is strictly unified to 1s, ensuring that the driving pulley starts from rest and can climb to the rated speed smoothly and accurately within this 1s along the ideal acceleration curve, avoiding the adverse effects of the startup shock on the system. When the synchronous pulley reaches the rated speed smoothly according to the preset rhythm, the PID controller of the CNC machine tool workbench control system starts working immediately. In the signal chain carefully constructed by Simulink, ensure that the PID controller accurately receives the real-time center of mass speed feedback from the workbench, according to the PID control algorithm:

[0128]

[0129] e[k]=r[k]-y[k];

[0130] Where r[k] represents the expected value of the kth step, y[k] represents the actual output of the kth step, e[k] represents the deviation of the kth step, u[k] represents the controller output of the kth step, and K P Represents the proportional gain coefficient, K I Indicates the integral coefficient, K D represents the differential coefficient, T SRepresents the sampling period (set to 0.001s). Through continuous looping and precise calculation of control signals, the moving speed of the driving table is gradually approached to the preset simulation running speed. During the operation of Simulink, the data acquisition module is enabled, and its acquisition frequency is fine-tuned to collect the moving speed of the center of mass of the worktable once every 0.01s. After the simulation is completed, in the Matlab script, the stored moving speed data is read in order, and the loop structure is used to calculate the speed deviation point by point to generate a detailed speed deviation sequence. Determine whether the speed deviation at different time nodes is less than the preset speed deviation threshold. If so, it is determined that the CNC machine tool worktable is running smoothly and the joint simulation ends; if not, it is determined that the CNC machine tool worktable is running unsteadily, and return to execute step S5 until the CNC machine tool worktable is running smoothly. Figure 5 The simulation control effect diagrams of 10mm / s, 20mm / s, 30mm / s and 40mm / s are shown. It can be seen that without PID control, the response of the CNC machine tool table is relatively unstable, showing large fluctuations or offsets. When PID control is applied, the response of the CNC machine tool table control system becomes more stable and controllable, and can reach and maintain near the set speed faster.

[0131] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0132] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0133] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A joint simulation method for the motion state and control system of a CNC machine tool worktable, characterized in that: include: Step S1: creating a three-dimensional model of a CNC machine tool workbench and setting material properties and constraint relationships of the three-dimensional model through Adams; Step S2: configuring the contact force and driving relationship of the CNC machine tool worktable in the three-dimensional model by Adams; Step S3: setting state variables for connecting Adams and Matlab and associating the state variables with the motion state parameters of the CNC machine tool worktable, and constructing a joint simulation model based on the motion state parameters; Step S4: Load the joint simulation model through Matlab and call Simulink to establish a PID-based Control strategy for CNC machine tool worktable control system; Step S5: taking the moving speed of the CNC machine tool worktable as the control target, adjusting the control parameters of the CNC machine tool worktable control system; Step S6: Run the joint simulation model and determine whether the CNC machine tool worktable moves smoothly according to the output of the CNC machine tool worktable control system. If yes, the joint simulation ends; otherwise, return to execute step S5.

2. The method for joint simulation of the motion state and control system of a CNC machine tool worktable according to claim 1 is characterized in that: The step S1 comprises: Step S11: constructing a three-dimensional model of the CNC machine tool workbench through three-dimensional modeling according to the assembly relationship between the various components of the CNC machine tool workbench; Step S12: Analyze the spatial relationship between the components, perform interference check on the 3D model through 3D modeling software, and determine whether there are overlapping components. If yes, execute step S11, otherwise execute step S13; Step S13: saving the three-dimensional model of the CNC machine tool workbench as a Parasolid (*.x_t) format file; Step S14: creating a new model in Adams, and importing the Parasolid (*.x_t) format file into the new model; Step S15: Setting the material properties and constraint relationships of the imported three-dimensional model through Adams.

3. The method for joint simulation of the motion state and control system of a CNC machine tool worktable according to claim 2 is characterized in that: The step S15 comprises: Step S151: defining material properties between components in the three-dimensional model in Adams; Step S152: Based on the material properties of different components, the material properties, mass properties and center of mass position of each component are solved by Adams; Step S153: establishing the constraint relationship between the components of the three-dimensional model through Adams, wherein the constraint relationship includes a fixed pair, a rotation pair and a helical pair.

4. The method for joint simulation of the motion state and control system of a CNC machine tool worktable according to claim 1, characterized in that: The step S2 comprises: Step S21: setting contact forces between contacting parts in the three-dimensional model by Adams, wherein the contact forces include contact forces between the workbench and the pressure plate, contact forces between the workbench and the machine tool bed, contact forces between the slider and the machine tool bed, and contact forces between the slider and the pressure plate; Step S22: creating a driving pulley and setting geometric parameters of the driving pulley through the Machinery module of Adams; Step S23: creating a driven pulley in the Machinery module and setting the geometric parameters of the driven pulley according to the geometric parameters of the driving pulley; Step S24: setting a constraint relationship and a position relationship between the driving pulley and the driven pulley, and connecting them to corresponding components; Step S25: creating a belt with the driving pulley and the driven pulley as connection objects through the Machinery module and setting properties of the belt, wherein the properties include at least length, width and elastic modulus; Step S26: establishing a driving function for the driving pulley, wherein the driving function includes a speed-time driving function.

5. The method for joint simulation of the motion state and control system of a CNC machine tool worktable according to claim 1, characterized in that: The step S3 comprises: Step S31: creating state variables for connecting to the Matlab interface through Adams; Step S32: establishing state variable associations between the driving pulley driving speed of the CNC machine tool worktable, the worktable center of mass displacement, the worktable center of mass speed, and the worktable center of mass acceleration and the state variables respectively; Step S33: Combine the state variables with associated relationships and establish a joint simulation model through the Controls module of Adams.

6. The method for joint simulation of the motion state and control system of a CNC machine tool worktable according to claim 5 is characterized in that: The step S33 comprises: Step S331: using the active pulley driving speed state variable as an input signal, and using the workbench center of mass displacement state variable, the workbench center of mass speed state variable, and the workbench center of mass acceleration state variable as output signals to construct a joint simulation model with Matlab as the target software; Step S332: setting the analysis type of the joint simulation model to nonlinear and the solver type to C++, and generating a .m format file corresponding to the joint simulation model.

7. The method for joint simulation of the motion state and control system of a CNC machine tool worktable according to claim 6 is characterized in that: The step S4 comprises: Step S41: running the .m format file through Matlab to load the model parameters of the joint simulation model; Step S42: input the interface command "adams_sys" in the command line of Matlab, and display the module window of the interface command adams_sys; Step S43: Import the adams_sub module in the adams_sys module window into the Simulink window newly created in Matlab and configure the joint simulation parameters; Step S44: constructing a CNC machine tool workbench control system in the Simulink window based on the PID control strategy.

8. The method for joint simulation of the motion state and control system of a CNC machine tool worktable according to claim 1, characterized in that: The step S5 comprises: Step S51: setting the proportional coefficient, integral coefficient and differential coefficient of the PID controller corresponding to the PID control strategy; Step S52: running the joint simulation model, and outputting the workbench center of mass displacement signal, center of mass velocity signal and center of mass acceleration signal to the CNC machine tool workbench control system in real time during the running of the joint simulation model; Step S53: using the workbench mass center displacement signal, the workbench mass center velocity signal and the workbench mass center acceleration signal, the CNC machine tool workbench control system calculates the active pulley adjustment speed based on the designed PID controller; Step S54: combining the PID adjustment speed with the rated speed of the driving pulley, and adjusting the proportional coefficient, the integral coefficient and the differential coefficient by analyzing the performance index of the CNC machine tool worktable.

9. The method for joint simulation of the motion state and control system of a CNC machine tool worktable according to claim 1, characterized in that: The step S6 comprises: Step S61: setting a plurality of simulation operation speeds of the CNC machine tool worktable, and determining a rated rotation speed of a driving pulley of the CNC machine tool worktable at the plurality of simulation operation speeds; Step S62: the time required for the driving pulley to accelerate from rest to the rated speed under the plurality of simulation running speeds is set to be the same; Step S63: when the driving pulley is accelerated to the rated speed, the moving speed of the CNC machine tool worktable is controlled by a PID controller so that the moving speed converges to the simulation running speed; Step S64: Analyze the moving speed of the CNC machine tool worktable under the control of the PID controller to determine whether the CNC machine tool worktable runs smoothly. If so, the joint simulation ends, otherwise return to execute step S5.

10. The method for joint simulation of the motion state and control system of a CNC machine tool worktable according to claim 9, characterized in that: The step S64 comprises: Step S641: obtaining the moving speed of the CNC machine tool worktable at different time nodes, and respectively calculating the speed deviation between the moving speed of the worktable at different time nodes and the simulation running speed; Step S642: Determine whether the speed deviation at different time nodes is less than a preset speed deviation threshold. If so, it is determined that the CNC machine tool workbench is running smoothly and the joint simulation ends. Simultaneously, if otherwise, it is determined that the CNC machine tool workbench is running unsteadily, return to execute step S5 until the CNC machine tool workbench is running smoothly.

Images