Milling force functional modeling method and system for machining track curvature sudden change
By using multi-dimensional feature analysis and functional modeling, the problem of insufficient prediction accuracy of existing milling force models during curvature abrupt changes has been solved, achieving efficient and accurate prediction of milling force and improving the processing efficiency and quality of large and complex aerospace structural parts.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-03-10
AI Technical Summary
Existing milling force models are unable to accurately predict milling forces during sudden changes in the curvature of the machining trajectory, leading to machining quality problems and low efficiency, and are particularly unsuitable for machining large and complex aerospace structural parts.
By analyzing and classifying multi-dimensional features, a functional representation model of cutting parameters is established. Combined with functional operators, a functional model of milling force is constructed to accurately capture the time-varying, parametric, and condition-dependent characteristics of curvature change machining, thereby enabling rapid prediction of milling force.
It improves the accuracy and efficiency of milling force prediction, is applicable to various curvature change characteristics, enhances machining efficiency and surface quality, and provides a theoretical basis for process parameter optimization and vibration suppression.
Smart Images
Figure CN121635110A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of numerical control machining, and particularly relates to a milling force functional modeling method and system for machining trajectory curvature mutation. BACKGROUND
[0002] With the acceleration of the development and production process of domestic large aircraft (such as C919), the demand for large integral aviation structural parts (such as large frames, beams, ribs, etc.) has increased dramatically. Such parts have the characteristics of "large size, integration, and complexity", and the number of curvature mutation features such as corners and cavities on them is huge. Taking a new type of aircraft integral wallboard as an example, the number of corners exceeds 3000. The machining of each corner needs to change the feed direction many times, resulting in a sharp increase in the number of machining trajectory curvature mutations.
[0003] In the curvature mutation area, the cutting layer parameters (such as cutting width and cutting depth) will change dramatically, and this change has the characteristics of time variation (change with time), parameter variation (change with machining position), and working condition dependence (dependence on tool, cutting parameters, etc. Specific conditions). This causes the excitation characteristics of the milling force to change dramatically, which easily leads to machining quality problems such as vibration, overcut, and tool wear. Currently, enterprises usually avoid these problems by reducing the feed speed or refining the tool path, but this seriously sacrifices the machining efficiency. According to statistics, in finish machining, the machining time of the curvature mutation process can account for more than 30% of the total machining time, while the material volume removed is less than 5%.
[0004] Accurate prediction of milling force is the key to mastering and controlling the dynamic behavior of the process system. Existing milling force models (such as cycloid model, circular arc approximation model, etc.) are mostly based on constant or slowly changing cutting parameters, and often simplify or even ignore the strong time-varying and parameter-varying characteristics of cutting parameters in the curvature mutation process. Especially in multi-axis machining and complex trajectories, the existing models have low solving efficiency, and it is difficult to apply them to force prediction for different types of curvature mutation features, which limits their real-time application in production sites. SUMMARY
[0005] The purpose of the present application is to provide a milling force functional modeling method and system for machining trajectory curvature mutation to solve the above problems.
[0006] To achieve the above purpose, the present application adopts the following technical solutions: In a first aspect, the present application provides a milling force functional modeling method for machining trajectory curvature mutation, comprising: Through part analysis, trajectory view and feature view analysis, the spatiotemporal evolution law of the tool-workpiece engagement area in the machining trajectory curvature mutation process is obtained. Based on the spatio-temporal evolution law, the cutting parameters with time-varying and parameter-varying characteristics are expressed as functions of feature categories, tool center coordinates, feed per tooth, cutting time and tool radius, to obtain a functional characterization model of the cutting parameters. With the cutting parameter functions as independent variables, a functional model of the milling force is constructed by combining an instantaneous milling force model and a functional operator, and the functional model is used to predict the milling force in the curvature mutation process of the machining trajectory.
[0007] Further, the spatio-temporal evolution law of the tool-work engagement area in the curvature mutation process of the machining trajectory is obtained through part analysis, trajectory view and feature view analysis, including: Through part analysis, trajectory view and feature view, the curvature mutation feature of the machining trajectory is analyzed in multiple dimensions and multiple views, and the geometric and machining characteristics of the feature are extracted; then, based on four dimensions of curvature positive / negative, trajectory angle (acute angle, right angle, obtuse angle), functionality / process and cutting / tool parameters, the curvature mutation feature is classified, and the spatio-temporal evolution law of the tool-work engagement area under each feature is obtained.
[0008] Further, the trajectory angle includes acute angle, right angle and obtuse angle.
[0009] Further, based on the spatio-temporal evolution law, the cutting parameters with time-varying and parameter-varying characteristics are expressed as functions of feature categories, tool center coordinates, feed per tooth, cutting time and tool radius, to obtain a functional characterization model of the cutting parameters, including:
[0010] wherein m is the feature category, determined by the four dimensions. i , y i is the tool center coordinate, f t is the feed per tooth, t is the cutting time, and R is the tool radius.
[0011] Further, with the cutting parameter functions as independent variables, a functional model of the milling force is constructed by combining an instantaneous milling force model and a functional operator, including:
[0012] wherein F is the milling force, g(.) is the functional operator, is the cutting width function, a p is Further, the functional model is used to predict the milling force in the curvature mutation process of the machining trajectory, wherein the curvature mutation feature machining process is divided into multiple stages, including a normal cutting stage, a cutting-in / cutting-out stage, a cutting boundary continuous change stage and a feed direction mutation stage.
[0013] In a second aspect, the present application provides a milling force functional modeling system for machining trajectory curvature mutation, comprising: a rule acquisition module configured to obtain the spatiotemporal evolution rule of the tool-workpiece engagement area during machining trajectory curvature mutation through part analysis, trajectory view analysis, and feature view analysis; a functionalization module configured to represent the cutting parameters with time-varying and parameter-varying characteristics as functions of feature categories, tool center coordinates, feed per tooth, cutting time, and tool radius based on the spatiotemporal evolution rule to obtain a functional representation model of the cutting parameters; a model construction module configured to construct a milling force functional model by using the functional operator with the cutting parameter functions as independent variables and combining an instantaneous milling force model, and predict the milling force during machining trajectory curvature mutation by using the functional model.
[0014] Further, the functional representation model of the cutting parameters with time-varying and parameter-varying characteristics represented as functions of feature categories, tool center coordinates, feed per tooth, cutting time, and tool radius based on the spatiotemporal evolution rule comprises:
[0015] wherein m is the feature category determined by the four dimensions.x i , y i is the tool center coordinate, f t is the feed per tooth, t is the cutting time, and R is the tool radius. The milling force functional model constructed by using the functional operator with the cutting parameter functions as independent variables and combining the instantaneous milling force model comprises:
[0016] wherein F is the milling force, g(.) is the functional operator, is the cutting width function.
[0017] In a third aspect, the present application provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the milling force functional modeling method for machining trajectory curvature mutation when executing the computer program.
[0018] In a fourth aspect, the present application provides a computer readable storage medium storing a computer program, wherein the computer program implements the steps of the milling force functional modeling method for machining trajectory curvature mutation when executed by a processor.
[0019] Compared with the prior art, the present application has the following technical effects: The application accurately captures the core working condition characteristics of the curvature mutation processing through multi-dimensional feature analysis and classification, combines the functional representation of the cutting parameters, fully considers the time-varying, parameter-dependent and working condition-dependent properties of the milling force, greatly improves the prediction accuracy, is suitable for various curvature mutation characteristics such as inner corner, outer corner and different angles, has strong universality and adaptability, avoids a large number of discrete calculations of the traditional method, realizes the rapid prediction of the milling force, can meet the on-site processing needs of large and complex parts, and simultaneously, the accurate prediction result can provide direct theoretical basis for process parameter optimization, tool path planning and vibration suppression, and effectively improves the machining efficiency and surface quality of complex parts such as aviation structural parts. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 is the overall flowchart of the milling force functional modeling method provided by the embodiment of the application.
[0021] Figure 2 is a multi-dimensional analysis view diagram of the curvature mutation process of the machining trajectory of a complex aviation structural part, including a trajectory view and a feature view.
[0022] Figure 3 is a multi-dimensional influence factor diagram affecting the space-time evolution of the tool-workpiece engagement area.
[0023] Figure 4 is a decomposition diagram of the corner cutting process, wherein: (a) shows the division of four stages of the cutting process.
[0024] (b) shows the change process of the actual cutting boundary.
[0025] (c) shows the dramatic change process of the actual cutting boundary in the curvature mutation feature processing.
[0026] Figure 5 is a comparison diagram of the dramatic change mechanism of the milling force excitation characteristics in the processing of different curvature mutation features.
[0027] Figure 6 is a function relationship diagram of the cutting width (cutting width) changing with the tool center position.
[0028] Figure 7 is the structural block diagram of the milling force prediction system provided by the embodiment of the application. DETAILED DESCRIPTION
[0029] The application is further described below in combination with the drawings: Embodiment 1, please refer to Figure 1 The application provides a milling force functional modeling method for curvature mutation of a machining trajectory, comprising: Through part analysis, trajectory view and feature view analysis, the time-space evolution law of the tool-workpiece engagement area in the machining trajectory curvature mutation process is obtained. Based on the time-space evolution law, the cutting parameters with time-varying and parameter-dependent characteristics are expressed as functions of feature categories, tool center coordinates, feed per tooth, cutting time and tool radius, and a functional characterization model of the cutting parameters is obtained. Taking the cutting parameter function as the independent variable, combining the instantaneous milling force model, a functional model of the milling force is constructed through a functional operator, and the functional model is used to predict the milling force in the machining trajectory curvature mutation process.
[0030] By analyzing the time-space evolution law of the tool-workpiece engagement area and establishing the functional characterization of the cutting parameters, the time-varying, parameter-dependent and working condition-dependent characteristics of the milling force in the curvature mutation process are fully considered, and the prediction accuracy is high.
[0031] Based on multi-dimensional feature classification and functional modeling, the model is applicable to different types (inside corner, outside corner, acute angle, right angle, etc.) of curvature mutation features, and has strong universality.
[0032] By functionalizing the cutting process parameters, the large amount of calculation caused by traditional discrete methods or trajectory intersection method is avoided, the rapid prediction of the milling force is realized, and the application requirements of on-site machining of large and complex parts are met.
[0033] In embodiment 2, the present application provides a milling force functional modeling method for machining trajectory curvature mutation, which comprises: Firstly, all curvature mutation features are extracted from the CAD model of the aviation structure to be machined through feature recognition technology. Then, the core three steps are entered: Step S1: analyze the time-space evolution law of the tool-workpiece engagement area.
[0034] A typical right-angle inside corner feature is analyzed by using the multi-dimensional analysis view as shown in the drawing. Figure 2
[0035] The feature position is determined in the part, and the machining is limited by the tool diameter.
[0036] Under the trajectory view, the change of the tool center trajectory at the corner and the influence of the tool geometry (such as radius R) on the actual cutting area are analyzed.
[0037] Under the feature view, the three-dimensional cutting process is projected onto a two-dimensional plane, and the process of forming a residual circular arc due to the positive curvature (inside corner) and the inability of the tool to completely cut into the sharp corner is clearly shown.
[0038] Based on Figure 3 The feature is categorized using four dimensions: positive curvature, right-angled trajectory angle, functional feature, and given a set of cutting / tool parameters (e.g., cutting width / tool radius < 1). Through spatial geometry and parametric modeling, the precise mathematical relationship between the tool-workpiece meshing boundary and time and tool position changes during machining of this specific feature category can be derived.
[0039] Step S2: Establish a functional representation of the cutting parameters.
[0040] Regarding the aforementioned right-angle interior corner features, the processing procedure can be based on... Figure 4 The process (a) is divided into four stages. We use the cutting width a as the basis. e Let's take an example and convert it into a function.
[0041] according to Figure 4 (b) and Figure 6 Based on the tool radius R and the tool center trajectory, the coordinates (x, y) of ae and the tool center can be calculated for each stage. i , y i The functional relationship between ) is as follows. For example, in the cut-in-cut-out phase (O2→O3), ae may appear as a parabola or a circular arc function.
[0042] Finally, by integrating all stages and introducing feature category identifier m, feed per tooth ft, and cutting time t, a functional model as shown in equation (1-1) is established. The model can automatically obtain input parameters from CAM files and post-processing information through a program.
[0043] Step S3: Construct the milling force functional model.
[0044] The cutting parameter function a obtained in step S2 e (...) is used as input and substituted into the classic instantaneous milling force model (such as the force coefficient model based on mechanics). Because a e The milling force itself is a complex function, not a constant value; therefore, the final milling force F is a function of this a. e (...) functionals.
[0045]
[0046] Where F is the milling force, and g(.) is the functional operator. This is the cutting width function.
[0047] In actual prediction, the system iterates through the tool position file, calculates the ae function value at each moment in real time, and then quickly outputs the milling force variation curve throughout the entire corner machining process. Its prediction results can accurately reflect, for example, the milling force variation curve during corner machining. Figure 5 and Figure 4The dramatic behavior shown in (c) is as follows.
[0048] This method first performs multidimensional analysis of curvature abrupt change characteristics through part views, trajectory views, and feature views, revealing the spatiotemporal evolution law of the tool-workpiece meshing area. Then, based on feature categories, tool position coordinates, cutting parameters, and time, a functionalized representation model of the cutting parameters is established. Finally, using this cutting parameter function as the independent variable, a milling force functional model is constructed to achieve accurate and rapid prediction of the dramatic changes in milling force during curvature abrupt changes. This invention overcomes the shortcomings of existing models in handling time-varying, parametric, and condition-dependent characteristics of cutting parameters, and is suitable for efficient machining and process optimization of various complex aerospace structural parts.
[0049] In another embodiment of the present invention, a milling force functional modeling system for sudden changes in the curvature of the machining trajectory is provided, which can be used to implement the above-mentioned milling force functional modeling method for sudden changes in the curvature of the machining trajectory. Specifically, the system includes: The pattern acquisition module is used to obtain the spatiotemporal evolution pattern of the tool-workpiece meshing area during the sudden change of curvature of the machining trajectory through part analysis, trajectory view and feature view analysis; The functionalization module is used to represent cutting parameters with time-varying and parametric characteristics as functions of feature category, tool center coordinates, feed per tooth, cutting time and tool radius based on spatiotemporal evolution laws, thus obtaining a functionalized representation model of cutting parameters; The model building module is used to construct a functional model of milling force by using the cutting parameter function as the independent variable and combining it with the instantaneous milling force model. This functional model is then used to predict the milling force during the sudden change of curvature of the machining trajectory.
[0050] The module division in this embodiment of the invention is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of the invention can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.
[0051] In another embodiment of the present invention, a computer device is provided, comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to achieve a corresponding method flow or corresponding function. The processor described in this embodiment of the present invention can be used for operating a milling force functional modeling method oriented towards abrupt changes in the curvature of the machining trajectory.
[0052] In another embodiment of the present invention, a storage medium is provided, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the milling force functional modeling method for abrupt changes in machining trajectory curvature in the above embodiments.
[0053] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0054] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0055] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0056] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A milling force functional modeling method for abrupt changes in machining trajectory curvature, characterized by, The method comprises the following steps: Through part analysis, trajectory view and feature view analysis, the time-space evolution law of the tool-workpiece engagement area in the machining trajectory curvature mutation process is obtained; Based on the time-space evolution law, the cutting parameters with time-varying and parameter-varying characteristics are expressed as functions of feature categories, tool center coordinates, feed per tooth, cutting time and tool radius, and a functional representation model of the cutting parameters is obtained; The functional model of the milling force is constructed by taking the cutting parameter function as an independent variable and combining the instantaneous milling force model through a functional operator, and the milling force in the machining trajectory curvature mutation process is predicted by using the functional model.
2. The milling force functional modeling method for machining trajectory curvature discontinuity according to claim 1, characterized in that, The method comprises the following steps: Through part analysis, trajectory view and feature view analysis, the time-space evolution law of the tool-workpiece engagement area in the machining trajectory curvature mutation process is obtained; 3. The milling force functional modeling method for machining trajectory curvature discontinuity according to claim 2, characterized in that, The geometric and machining characteristics of the curvature mutation feature are extracted through multi-dimensional and multi-view analysis of the curvature mutation feature of the machining trajectory based on the curvature sign, trajectory angle (acute angle, right angle and obtuse angle), functionality / technologicality and cutting / tool parameters, and the time-space evolution law of the tool-workpiece engagement area under different features is obtained.
4. The milling force functional modeling method for machining trajectory curvature discontinuity according to claim 1, characterized in that, The trajectory angle includes acute angle, right angle and obtuse angle. The functional representation model of the cutting parameters is obtained by expressing the cutting parameters with time-varying and parameter-varying characteristics as functions of feature categories, tool center coordinates, feed per tooth, cutting time and tool radius based on the time-space evolution law, wherein m is a feature class determined from the four dimensions.x i , y i is the tool center coordinate, f t is the feed per tooth, t is the cutting time, and R is the tool radius.
5. The machining trajectory curvature discontinuity oriented milling force functional modeling method according to claim 1, characterized in that, The method comprises the following steps: where F is the milling force, g(.) is a functional operator, is the cutting width function.
6. The milling force functional modeling method for machining trajectory curvature discontinuity according to claim 5, wherein, The functional model of the milling force is constructed by taking the cutting parameter function as an independent variable and combining the instantaneous milling force model through a functional operator, and the milling force in the machining trajectory curvature mutation process is predicted by using the functional model.
7. A milling force functional modeling system oriented towards abrupt changes in machining trajectory curvature, characterized by, The functional model of the milling force is constructed by taking the cutting parameter function as an independent variable and combining the instantaneous milling force model through a functional operator, and the milling force in the machining trajectory curvature mutation process is predicted by using the functional model. The method comprises the following steps: The rule acquisition module is configured to obtain the time-space evolution law of the tool-workpiece engagement area in the machining trajectory curvature mutation process through part analysis, trajectory view and feature view analysis; The functionalization module is configured to obtain the functional representation model of the cutting parameters by expressing the cutting parameters with time-varying and parameter-varying characteristics as functions of feature categories, tool center coordinates, feed per tooth, cutting time and tool radius based on the time-space evolution law; 8. The milling force functional modeling system for machining trajectory curvature discontinuity according to claim 7, wherein, The model construction module is configured to construct the functional model of the milling force by taking the cutting parameter function as an independent variable and combining the instantaneous milling force model through a functional operator, and predict the milling force in the machining trajectory curvature mutation process by using the functional model. The functional representation model of the cutting parameters is obtained by expressing the cutting parameters with time-varying and parameter-varying characteristics as functions of feature categories, tool center coordinates, feed per tooth, cutting time and tool radius based on the time-space evolution law, wherein m is a feature class determined from the four dimensions.x i , y i is the tool center coordinate, f t is the feed per tooth, t is the cutting time, and R is the tool radius. The functional model of the milling force is constructed by taking the cutting parameter function as an independent variable and combining the instantaneous milling force model through a functional operator, and the milling force in the machining trajectory curvature mutation process is predicted by using the functional model. where F is the milling force, g(.) is a functional operator, is the cutting width function.
9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the computer program to realize the steps of the milling force functional modeling method for machining trajectory curvature mutation according to any one of claims 1 to 6.
10. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 9. The computer program, when executed by a processor, implements the steps of the method for milling force functional modeling oriented to machining trajectory curvature discontinuity according to any one of claims 1 to 6.