Blanking size accurate control method and system oriented to assembly consistency

Abstract

The invention discloses a blanking size accurate control method and system oriented to assembly consistency, and relates to the technical field of computer-aided manufacturing and assemblation.The method comprises the steps that cooperation control points are identified based on assembly design data, blanking key size parameters associated with the cooperation control points are determined, and a mapping relation is established; determining a geometric action path of transferring the blanking critical dimension parameters to the matching control point along the geometric characteristics of the part; applying single-parameter disturbance and multi-parameter combined disturbance in the combined parameter space to obtain a predicted geometric response and an actual geometric response; establishing a nonlinear coupling constraint relation according to the geometric response residual error, and forming an assembly consistency constraint rule; and judging the blanking key size parameter combination to obtain a joint allowable area, converting the joint allowable area into a size output limiting rule, and executing blanking operation to form an assembly body meeting the assembly consistency requirement. According to the method, the influence of multi-parameter joint change on assembly geometry is considered, and the blanking size is controlled to realize assembly consistency.

Description

Technical Field

[0001] This application relates to the field of computer-aided manufacturing and assembly technology, and in particular to a method and system for precise control of blanking dimensions for assembly consistency. Background Technology

[0002] In the field of mechanical manufacturing and assembly, the blanking process is a fundamental step in the parts manufacturing process, and the accuracy of the blanking dimensions directly determines the quality of subsequent processing and assembly precision. As the structure of assemblies becomes increasingly complex, the requirements for the geometric consistency of parts in the assembly process are constantly increasing. Assembly consistency depends not only on whether individual dimensional parameters meet their nominal dimensions or tolerance requirements, but also on the combined influence of multiple key blanking dimensional parameters, under combined values, on the geometric spatial position and orientation of the mating control point. In actual assembly, multiple key blanking dimensional parameters often act together on the same mating control point, and their combined changes are transmitted and amplified through geometric topological relationships and assembly constraints, thus affecting the overall assembly quality of the assembly.

[0003] Existing methods for controlling blanking dimensions typically focus on a single dimensional parameter or constrain each dimensional parameter individually based on independent tolerances. While these methods can guarantee the machining accuracy of individual dimensional parameters to a certain extent, they struggle to accurately reflect the interrelationships between different key blanking dimensional parameters in assembly scenarios where multiple parameters interact. Especially when multiple dimensional parameters change simultaneously, their impact on the geometric spatial position and orientation of mating control points often exhibits non-linear characteristics. The lack of comprehensive analysis of assembly geometric constraints means that even if each blanking dimensional parameter individually meets tolerance requirements, the combined changes of multiple dimensional parameters during assembly can still lead to spatial displacement or orientation deviations of the mating control points, thus affecting assembly consistency.

[0004] In summary, existing blanking dimension control methods lack in-depth analysis of the synergistic effects between multiple parameters, and cannot cope with the complex impact of the combined changes of multiple blanking dimension parameters during actual assembly. Furthermore, they fail to fully utilize the geometric information and constraints in the assembly design, making it difficult to effectively guarantee assembly consistency and stability when multiple blanking dimension parameters change simultaneously. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a precise control method and system for blanking dimensions oriented towards assembly consistency. By analyzing the assembly geometric response under the joint variation of multiple parameters, the nonlinear coupling effect formed by multiple key blanking dimension parameters under the joint value conditions is characterized. Based on the assembly consistency requirements, dimension output constraint rules that can be directly used for blanking equipment are formed, thereby achieving forward constraints on assembly consistency during the blanking stage.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for precise control of blanking dimensions for assembly consistency, comprising the following steps: Based on the assembly design data of the target assembly, identify the mating control points, determine the key dimensions of the blanking associated with each mating control point, and establish the mapping relationship between the mating control points and the key dimensions of the blanking. Based on the mapping relationship, the geometric action path of the key dimension parameters of blanking is determined along the geometric features of the design objects of each part in the assembly to the corresponding mating control point. The geometric action path characterizes the transmission relationship and action link of the key dimension parameters of blanking to the geometric response of the mating control point. Based on the geometric action path, in the joint parameter space composed of the key dimensions of the blanking that are mapped to the same mating control point, single-parameter perturbations are applied to each key dimension of the blanking to obtain the predicted geometric response of the corresponding mating control point under the joint change of single-parameter perturbations; and multi-parameter joint perturbations are applied in the joint parameter space to obtain the actual geometric response of the corresponding mating control point. Based on the residual vector between the predicted geometric response and the actual geometric response, a nonlinear coupling constraint relationship is established between the key dimensions of each blanking material that are mapped to the same mating control point, forming an assembly consistency constraint rule. Based on the assembly consistency constraint rules, the combination of each blanking key dimension parameter in the joint parameter space is determined, and the combination of blanking key dimension parameters that satisfies the assembly consistency constraint rules is determined as the joint allowable region, which is used to limit the allowable combination relationship of blanking key dimension parameters when the joint changes. The combined permitted area is converted into a size output restriction rule that the blanking equipment can execute, and the blanking operation is performed under the constraint of the size output restriction rule to obtain multiple blanked parts; the multiple blanked parts are assembled to form an assembly that meets the assembly consistency requirements.

[0007] Secondly, the present invention provides a precise blanking dimension control system for assembly consistency, comprising: The mapping relationship establishment module is used to identify mating control points based on the assembly design data of the target assembly, determine the key dimensions of blanking associated with each mating control point, and establish the mapping relationship between the mating control points and the key dimensions of blanking. The geometric action path generation module is used to determine the geometric action path of the blanking key dimension parameters along the geometric features of the design objects of each part in the assembly to the corresponding mating control point according to the mapping relationship. The geometric action path represents the transmission relationship and action link of the blanking key dimension parameters to the geometric response of the mating control point. The geometric response acquisition module is used to apply single-parameter perturbations to each critical dimension parameter of the material cutting process within a joint parameter space consisting of critical dimension parameters of the material cutting process mapped to the same mating control point, based on the geometric action path, to obtain the predicted geometric response of the corresponding mating control point under the joint change of single-parameter perturbations; and to apply multi-parameter joint perturbations within the joint parameter space to obtain the actual geometric response of the corresponding mating control point. The assembly consistency constraint rule generation module is used to establish nonlinear coupling constraint relationships between key material cutting dimension parameters mapped to the same mating control point based on the residual vector between the predicted geometric response and the actual geometric response, thus forming assembly consistency constraint rules. The joint allowable area determination module is used to determine the combination of each blanking key dimension parameter in the joint parameter space according to the assembly consistency constraint rules, and to determine the blanking key dimension parameter combination that satisfies the assembly consistency constraint rules as the joint allowable area, which is used to limit the allowable combination relationship of blanking key dimension parameters when the joint changes. The blanking execution and assembly module is used to convert the joint allowed area into dimensional output restriction rules that the blanking equipment can execute, and to perform blanking operations under the constraints of the dimensional output restriction rules to obtain multiple blanked parts; and to assemble the multiple blanked parts to form an assembly that meets the assembly consistency requirements.

[0008] One or more technical solutions provided in this invention have at least the following technical effects or advantages: Based on the assembly design data of the target assembly, identify mating control points, determine the key blanking dimension parameters associated with each mating control point, and establish a mapping relationship; according to the mapping relationship, determine the geometric action path of the key blanking dimension parameters transmitted along the geometric features of the part to the mating control points; apply single-parameter perturbation and multi-parameter joint perturbation to the key blanking dimension parameters in the joint parameter space to obtain the predicted geometric response and actual geometric response of the corresponding mating control points; establish a nonlinear coupling constraint relationship between the key blanking dimension parameters based on the residual between the predicted geometric response and the actual geometric response, forming an assembly consistency constraint rule; determine the combination of key blanking dimension parameters in the joint parameter space according to the assembly consistency constraint rule, obtain the joint allowable region, and convert it into a dimension output restriction rule executable by the blanking equipment; perform the blanking operation under the constraint of this rule to form an assembly that meets the assembly consistency requirements. Compared with the prior art, this invention can comprehensively analyze the perturbation effect of blanking dimension parameters by combining the joint perturbation analysis of blanking dimension parameters and the assembly consistency constraint, consider the nonlinear coupling effect of different blanking dimension parameters, and control the blanking dimensions to meet the assembly consistency requirements.

[0009] The above description is merely an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A flowchart illustrating a method for precise control of blanking dimensions for assembly consistency provided in an embodiment of this application; Figure 2 A schematic diagram of a precise blanking dimension control system for assembly consistency provided in this application embodiment; Figure labeling: Module 11 for establishing mapping relationship, Module 12 for generating geometric action path, Module 13 for obtaining geometric response, Module 14 for generating assembly consistency constraint rules, Module 15 for determining joint allowable area, and Module 16 for material cutting execution and assembly. Detailed Implementation

[0012] The exemplary embodiments of this disclosure are described below with reference to the accompanying drawings, including various details of the embodiments to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this disclosure. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0013] Example 1, as Figure 1 As shown, this application provides a method for precise control of blanking dimensions for assembly consistency, comprising: S1. Identify mating control points based on the assembly design data of the target assembly, determine the key dimensions of blanking associated with each mating control point, and establish a mapping relationship between the mating control points and the key dimensions of blanking. Furthermore, the establishment of the mapping relationship includes: Based on the assembly design data of the target assembly, the geometric topological relationships between the geometric features of each part design object in the assembly, as well as the assembly constraint elements acting between different part design objects and their geometric features are obtained. Based on geometric topological relationships and assembly constraint elements, identify mating control points in the assembly. These mating control points are key position points that characterize the geometric spatial position and orientation of the part design object, including contact position control points, positioning datum position control points, and alignment datum position control points. For each mating control point, the dimensional parameters associated with its geometric spatial position and orientation are determined as the key dimensional parameters for blanking, and a many-to-many relationship is established between the mating control point and the key dimensional parameters for blanking.

[0014] Specifically, the assembly design data of the target assembly is obtained. This assembly design data includes at least: a. the nominal geometric dimensions of each part, used to characterize the reference dimensions of each geometric feature in the design state; b. geometric feature information, used to describe the feature surfaces, feature holes, feature axes, boundary features, and the connection relationships between geometric features contained in each part; c. assembly relationship information, used to describe the mating forms, contact methods, reference association methods, and degree-of-freedom restriction methods between part design objects; d. structural connection information, used to describe the connection hierarchy and assembly sequence of parts in the assembly; e. assembly accuracy requirements, used to limit the geometric features. The precision constraint information for permissible deviation ranges includes dimensional tolerances, positional tolerances, and geometric tolerances, as well as other related geometric tolerance constraints used to limit the spatial position, orientation, and posture relationships of geometric features. Dimensional tolerances limit the permissible deviation range for linear dimensions such as length, spacing, and thickness. Positional tolerances limit the permissible deviation range for the center position, axial position, or relative positional relationship of geometric features, including positional tolerances, coaxiality tolerances, symmetry tolerances, and concentricity tolerances. Geometric tolerances limit the permissible deviation range for the shape and orientation relationships of geometric features, including flatness, straightness, roundness, cylindricity, and directional and angular tolerances such as parallelism, perpendicularity, and inclination. The assembly design data is analyzed to obtain the geometric topological relationships between the internal geometric features of each part design object in the target assembly, as well as the assembly constraint elements acting between different part design objects and their geometric features to restrict their relative orientational degrees of freedom. Assembly constraint elements include at least: constraint elements for restricting relative translational degrees of freedom, such as surface mating assembly constraints, stop assembly constraints, and axis positioning assembly constraints; constraint elements for restricting relative rotational degrees of freedom, such as coaxial assembly constraints, perpendicular assembly constraints, and parallel assembly constraints; and assembly datum constraint elements for defining assembly datums, such as constraints that use a specific datum surface, datum hole, or datum axis as an assembly reference. For each assembly constraint element, combined with geometric topological relationships, key position points are identified as mating control points to define the geometric spatial position and orientation of part design objects in the target assembly. These include: contact position control points, which characterize the geometric position points where two part design objects make direct contact, such as representative points in the surface contact area or the start and end points of line contact; positioning datum position control points, which define the datum position of part design objects in the assembly, such as the center point of a positioning hole or a reference point on a datum surface; and alignment datum position control points, which define the alignment relationship between multiple part design objects, such as the axis endpoints in a coaxial structure or the datum boundary points in a coplanar structure. For each mating control point, based on the geometric features to which the mating control point is attached and its corresponding assembly constraints, key blanking dimension parameters are identified in the assembly design data of the target assembly to define the geometric spatial position and orientation of the mating control point. These key blanking dimension parameters are dimensional parameters that are transmitted along the geometric features and ultimately act on the mating control point through geometric topological relationships and assembly constraints. The key blanking dimension parameters include at least: face-to-face distance parameters, hole center position parameters and hole axis direction parameters, feature axis position parameters and orientation parameters, boundary length parameters and boundary spacing parameters, relative angle parameters, and reference surface position parameters and orientation parameters. The nominal values ​​of the key blanking dimension parameters are taken from the design dimensions of the corresponding geometric features in the assembly design data and are used as reference dimension values ​​for subsequent disturbance analysis. Then, a many-to-many mapping relationship is established between the mating control point and its corresponding key blanking dimension parameter; that is, each mating control point is associated with at least one key blanking dimension parameter, and each key blanking dimension parameter may be associated with one or more mating control points simultaneously (for example, the same axis length parameter may be associated with multiple mating control points simultaneously).

[0015] S2. Based on the mapping relationship, determine the geometric action path of the key dimension parameters of blanking to the corresponding mating control point along the geometric features of the design object of each part in the assembly. The geometric action path represents the transmission relationship and action link of the key dimension parameters of blanking to the geometric response of the mating control point. Furthermore, the determination of the geometric action path includes: Identify the geometric features to which each mating control point in the assembly depends, as well as the geometric features to which each critical dimension parameter of the blanking depends; Based on the mapping relationship between the control point and the key dimension parameters of the blanking, and according to the geometric topology and assembly constraint elements, the geometric interaction path between the geometric feature to which the key dimension parameter of the blanking is attached and the geometric feature to which its corresponding control point is attached is determined. The geometric interaction path is used to characterize the transmission relationship between each key dimension parameter of the blanking and the geometric spatial position and orientation of the control point.

[0016] Specifically, for each mating control point in the assembly, the geometric features attached to that control point in the assembled state are determined. These geometric features, under the influence of assembly constraints, are geometric feature objects that characterize the geometric spatial position and orientation of the control point. Simultaneously, the geometric features attached to each critical blanking dimension parameter in the assembly are determined. These geometric features include feature surfaces, feature holes, feature axes, or boundary features. Then, based on the geometric topological relationships between the internal geometric features of each part design object in the target assembly, and the assembly constraint elements acting on different part design objects and their geometric features to restrict their relative orientation degrees of freedom, the geometric action path between the geometric features to which the blanking key dimension parameters are attached and the geometric features to which their corresponding mate control points are attached is determined under the mapping relationship between the mate control points and the blanking key dimension parameters. The geometric action path is as follows: the geometric feature to which the blanking key dimension parameters are attached is used as the starting geometric feature node, and it extends step by step along the constraint link formed by the geometric topological relationship and the assembly constraint elements until the geometric feature to which the mate control point is attached is used as the ending geometric feature node. Through the geometric action path, it is clear that the blanking key dimension parameters, through the geometric features to which they are attached, exert geometric constraint influence on the geometric features to which the mate control points are attached, thereby characterizing the transmission relationship of the blanking key dimension parameters to the geometric spatial position and orientation of the mate control points. For the same mate control point, multiple geometric action paths from different blanking key dimension parameters can be determined; for the same blanking key dimension parameter, multiple geometric action paths leading to different mate control points can be determined.

[0017] Example 1: A critical dimension parameter for material cutting affects multiple fit control points: The target assembly includes a first part and a second part. The first part has a reference surface B and a mounting surface A, and the second part has a mating surface A′ that mates with the mounting surface A of the first part. The key dimension parameter D1 for blanking is the surface-to-surface distance between the reference surface B and the mounting surface A on the first part, and this parameter is attached to both the reference surface B and the mounting surface A. A first mating control point P1 characterizes the contact position between the first part and the second part at the mounting surface A, and P1 is attached to the mounting surface A of the first part. A second mating control point P2 characterizes the assembly posture of the second part relative to the first part, and P2 is attached to the positioning axis L of the second part, which establishes an assembly constraint with the first part through the mounting surface A. Based on the mapping relationship between the fit control points and the key dimensions of the blanking, it is determined that parameter D1 simultaneously affects both fit control points P1 and P2, thus forming the following geometric action path: (1) Reference plane B → Geometric topological relationship between reference plane B and mounting plane A in the first part → Mounting plane A → Surface fitting assembly constraint between mounting plane A of the first part and assembly mating plane A′ of the second part → Mounting plane A (geometric features to which the mating control point P1 is attached); (2) Reference plane B → Geometric topological relationship between reference plane B and mounting plane A in the first part → Mounting plane A → Axial positioning assembly constraint between mounting plane A of the first part and positioning axis L of the second part → Positioning axis L (geometric features to which control point P2 is attached).

[0018] Example 2: Multiple critical dimensional parameters for material cutting collectively affect a single fit control point: The target assembly includes a first part and a second part. The first part has a mounting hole H and a positioning end face C. The second part is assembled with the first part through the mounting hole H and the positioning end face C. The control point P3 characterizes the spatial position and orientation of the second part relative to the first part. The control point P3 is attached to the spatial positioning geometry (axis-end face positioning structure) determined by the assembly positioning axis M and the positioning end face N of the second part. The key dimensions for blanking associated with the mating control point P3 include: Parameter D2: The center position parameter of mounting hole H, to which the geometric feature to which it is attached is the characteristic axis of mounting hole H. Parameter D3: The surface-to-surface distance between the positioning end face C on the first part and another reference surface B. The attached geometric features are the positioning end face C and the reference surface B. Based on the mapping relationship between the fit control point and the key dimension parameters of the blanking, it is determined that both parameter D2 and parameter D3 affect the same fit control point P3, thus forming the following geometric action path: (1) Feature axis of mounting hole H → coaxial assembly constraint between mounting hole H of the first part and assembly positioning axis M of the second part → assembly positioning axis M (one of the geometric features to which the mating control point P3 is attached); (2) Positioning end face C → Geometric topological relationship between positioning end face C and datum surface B in the first part → Datum surface B → Stop assembly constraint between datum surface B in the first part and positioning end face N of the second part → Positioning end face N (one of the geometric features to which the control point P3 is attached).

[0019] S3. Based on the geometric action path, in the joint parameter space composed of the key dimensions of the material cutting mapped to the same mating control point, apply single-parameter perturbation to each key dimension of the material cutting to obtain the predicted geometric response of the corresponding mating control point under the joint change of single-parameter perturbation; and apply multi-parameter joint perturbation in the joint parameter space to obtain the actual geometric response of the corresponding mating control point. Furthermore, obtaining the predicted geometric response and the actual geometric response includes: For each mating control point, based on the mapping relationship between the mating control point and the key dimension parameters of the blanking, the key dimension parameters of the blanking mapped to the mating control point constitute a joint parameter space; Based on the geometric action path, in the joint parameter space, single-parameter perturbations are applied to each material cutting key dimension parameter mapped to the same mating control point, and the spatial displacement change vector and attitude change vector of the mating control point under each single-parameter perturbation condition are obtained. Based on the spatial displacement change vector and attitude change vector, the predicted geometric response of the corresponding control point under the joint change of single-parameter disturbance is obtained by weighted linear superposition. This includes the predicted spatial displacement change vector and the predicted attitude change vector, and the calculation formula is as follows: ; Where j is the control point number and i is the critical dimension parameter number for material cutting. This represents the total number of critical dimension parameters for blanking mapped to the mating control point j. and These are the predicted spatial displacement change vector and the predicted attitude change vector for the control point j, respectively. and These are the spatial displacement change vector and attitude change vector of control point j under the disturbance condition of the critical dimension parameter i during material feeding, respectively. The weighting coefficient corresponding to the critical dimension parameter of the i-th blank is calculated using the following formula: ; in, For the summation index, =1,2,..., , and These are the control points j for the critical dimensions of the blanking process. The spatial displacement change vector and attitude change vector under disturbance conditions To match the scale adjustment factor of control point j, the scale adjustment factor is used to convert the attitude change vector into an equivalent quantity with the same dimensions as the spatial displacement change vector. Within the joint parameter space, multiple joint perturbations are applied simultaneously to the key dimensions of the material cutting that are mapped to the same mating control point to obtain the actual geometric response of the mating control point, including the actual spatial displacement change vector and the actual attitude change vector.

[0020] Specifically, for each mating control point j, based on the mapping relationship between the mating control point and the critical dimension parameters for blanking, the critical dimension parameters for blanking mapped to that mating control point are obtained, forming a parameter set. ;in, Numbering of key dimensions for material cutting. This represents the total number of critical dimension parameters for blanking mapped to the mating control point j. The combinations of these critical dimension parameters are used as the joint parameter space. A multi-dimensional space is constructed using the identified critical dimension parameters as dimensions, with each dimension corresponding to a critical dimension parameter. Each point in this space represents a possible combination of critical dimension parameters. The space contains all possible parameter combinations for subsequent single-parameter perturbation, joint perturbation, and assembly consistency constraint analysis. This joint parameter space acts as an "analysis container," where perturbations can be applied to single-parameter and multi-parameter combinations to obtain the predicted and actual geometric responses. The joint parameter space for each control point is independent and reflects the impact of joint changes in the associated parameters of that control point on its geometric state. Based on this, and using the determined geometric action path, the geometric transfer relationship of each blanking key dimensional parameter is obtained, which is transmitted step by step along the geometric features of the assembly to the mating control point. The geometric action path serves as the basis for the transmission of the blanking key dimensional parameter disturbance to the geometric response of the mating control point. With each blanking key dimensional parameter taking its nominal value, based on the nominal geometric dimensions, geometric topology, and corresponding assembly constraint elements of each part design object, the geometric constraint is solved using the geometric constraint solution method to determine the nominal pose of each part design object in the assembly coordinate system. Based on this, the spatial position and orientation corresponding to the nominal state of each mating control point are calculated and obtained, serving as the reference geometric state for disturbance analysis. First, for each critical dimension parameter of the blanking process mapped to the same mating control point, while keeping the nominal values ​​of other critical dimension parameters unchanged, the allowable disturbance amplitude is determined for different types of critical dimension parameters based on the tolerance type of the corresponding geometric feature in the assembly design data: If the critical dimension parameter is a length or distance parameter, the upper and lower limits of the allowable disturbance are determined based on the upper and lower deviation values ​​of the dimensional tolerance of the corresponding geometric feature; if the critical dimension parameter is a position parameter, half of the position tolerance of the corresponding geometric feature is used as the allowable disturbance amplitude of the parameter to limit the maximum displacement of the corresponding geometric center point or axis; if the critical dimension parameter is a direction or attitude parameter, the form and position tolerance of the corresponding geometric feature is converted into an equivalent spatial displacement disturbance amplitude based on the form and position tolerance of the corresponding geometric feature and the length of the action arm corresponding to the attitude change, which is used as the allowable disturbance amplitude of the parameter. Based on the allowable disturbance amplitude, a corresponding allowable disturbance range is determined for each critical dimension parameter of the material cutting process. Within the allowable disturbance range, the disturbance amount of the critical dimension parameter of the material cutting process is selected. And apply it to change the critical dimension parameter of the blanking from its nominal value to the nominal value + Then, assembly geometry is solved to obtain the geometric state changes of the corresponding mating control points, resulting in the spatial displacement change vector and the attitude change vector caused by the disturbance. The spatial displacement change vector is used to characterize the position change of the mating control point in three-dimensional space, and the attitude change vector is used to characterize the angular change of the attitude of the part design object corresponding to the mating control point. Based on the spatial displacement change vector and attitude change vector obtained by the matching control point under various single-parameter disturbance conditions, the geometric responses of multiple key blanking dimension parameters mapped to the matching control point are weighted and linearly superimposed to obtain the predicted geometric response of the matching control point under the joint change of single-parameter disturbance conditions, including the predicted spatial displacement change vector and the predicted attitude change vector. The calculation formula is as follows: ; Where j is the control point number and i is the critical dimension parameter number for material cutting. This represents the total number of critical dimension parameters for blanking mapped to the mating control point j. and These are the predicted spatial displacement change vector and the predicted attitude change vector for the control point j, respectively. and These are the spatial displacement change vector and attitude change vector of control point j under the disturbance condition of the critical dimension parameter i during material feeding, respectively. Here is the weighting coefficient corresponding to the i-th critical dimension parameter for blanking. The weighting coefficient characterizes the relative contribution of each critical dimension parameter to the geometric response of the mating control point. It is determined based on the amplitude of the geometric response caused by the disturbance of each single parameter, and the calculation formula is: ; in, For the summation index, ; and These are the control points j for the critical dimensions of the blanking process. The spatial displacement change vector and attitude change vector under disturbance conditions To accommodate the scale adjustment factor of control point j, this is used to convert the attitude change vector into an equivalent quantity with the same dimensions as the spatial displacement change vector, making them summable. Scale adjustment factor Based on the length of the working arm from the control point j to its corresponding attitude change reference rotation axis. Sure, The rotation axis is the reference axis around which the attitude change of the part design object corresponding to the mating control point mainly occurs, and the length of the action arm is the geometric distance from the rotation axis to the mating control point, which is used to map the attitude angle change into a comparable linear displacement amplitude. Within the joint parameter space, for multiple key dimensions of the material cutting that are mapped to the same mating control point, the corresponding disturbance amounts are selected within their respective allowable disturbance ranges. Simultaneously apply multi-parameter joint perturbation to change each critical dimension parameter of the blanking from its nominal value to its nominal value + Based on the geometric action path, assembly geometry is solved to obtain the actual geometric response of the mating control point under the multi-parameter joint disturbance condition, including the actual spatial displacement change vector and the actual attitude change vector. The actual geometric response is used to characterize the true comprehensive effect of multiple key dimensional parameters of the material cutting on the geometric spatial position and attitude of the mating control point under the joint change condition.

[0021] S4. Based on the residual vector between the predicted geometric response and the actual geometric response, establish the nonlinear coupling constraint relationship between each key dimension parameter of the blanking that is mapped to the same mating control point, and form the assembly consistency constraint rule. Furthermore, the formation of the assembly consistency constraint rules includes: Based on the predicted spatial displacement change vector and predicted attitude change vector obtained from the predicted geometric response, and the actual spatial displacement change vector and actual attitude change vector obtained from the actual geometric response, the residual vector of the control point is calculated, and the residual vector includes the spatial displacement residual vector and the attitude residual vector. Based on the residual vector, the nonlinear coupling constraint relationship between the key dimensions of each blanking material mapped to the same mating control point is determined. Based on the nonlinear coupling constraint relationship and the allowable deviation thresholds of spatial displacement and attitude corresponding to the mating control point, assembly consistency constraint rules are formed.

[0022] Specifically, for each coordinated control point, after obtaining the predicted and actual geometric responses, the residual vectors of the coordinated control point are calculated based on the predicted spatial displacement change vector and predicted attitude change vector obtained under single-parameter joint perturbation conditions, and the actual spatial displacement change vector and actual attitude change vector obtained under multi-parameter joint perturbation conditions. These residual vectors include spatial displacement residual vectors and attitude residual vectors. The spatial displacement residual vector characterizes the deviation of the actual spatial displacement change of the coordinated control point from the predicted geometric response, and the attitude residual vector characterizes the deviation of the actual attitude change of the coordinated control point from the predicted geometric response. The calculation formula is as follows: , ;in, and These are the spatial displacement residual vector and attitude residual vector of the control point j, respectively. and These are the actual spatial displacement change vector and the actual attitude change vector of the control point j, respectively. and These are the predicted spatial displacement change vector and the predicted attitude change vector for the control point j, respectively. Next, based on the spatial displacement residual vector and attitude residual vector, a correspondence is established between the combined values ​​of each blanking key dimension parameter mapped to the same mating control point and the geometric deviation residual predicted by this combined value combination under assembly constraints. Since the influence of each blanking key dimension parameter on the geometric spatial position and attitude of the mating control point is not a simple linear superposition when they change together, the residual vector reflects the deviation of the geometric response of the mating control point from the predicted geometric response under the combined value conditions. This deviation reflects the mutual influence characteristics among multiple blanking key dimension parameters. Then, by analyzing the variation patterns of the spatial displacement residual vector and attitude residual vector obtained under different combined values ​​of blanking key dimension parameters mapped to the same mating control point, a correspondence is established between the combined changes of blanking key dimension parameters and the geometric deviation residual of the mating control point. When the residual vector exhibits a nonlinear variation characteristic with the combined values ​​of the blanking key dimension parameters, it indicates that there is a mutual influence among the blanking key dimension parameters under the combined change conditions, thus forming a nonlinear coupling constraint relationship to characterize the influence of the combined values ​​of multiple blanking key dimension parameters on the geometric consistency of the mating control point. Then, based on the positional or dimensional tolerances of the geometric features to which the mating control point j depends in the assembly design data, the permissible deviation threshold for spatial displacement is calculated. The attitude tolerance threshold is determined by the directional or angular tolerance corresponding to the geometric features to which it is attached. The threshold is used to limit the maximum permissible spatial displacement deviation and maximum attitude deviation of the mating control points under varying joint parameters. Finally, combining the nonlinear coupling constraint relationship with the permissible spatial displacement deviation threshold and attitude deviation threshold, assembly consistency constraint rules are formed: It is used as the basis for determining whether the combined values ​​of multiple key dimension parameters meet the requirements of assembly consistency.

[0023] S5. Based on the assembly consistency constraint rules, determine the combination of each blanking key dimension parameter in the joint parameter space, and determine the blanking key dimension parameter combination that satisfies the assembly consistency constraint rules as the joint allowable area, which is used to limit the allowable combination relationship of blanking key dimension parameters when the joint changes. Furthermore, the determination of the joint permitted region includes: Within the joint parameter space, for each mating control point, the combination of key dimensions for blanking mapped to the same mating control point is determined according to the assembly consistency constraint rules based on the spatial displacement residual vector and attitude residual vector of the mating control point, as well as the spatial displacement allowable deviation threshold and attitude allowable deviation threshold. The set of values ​​corresponding to each combination of values ​​that satisfies the assembly consistency constraint rule in the joint parameter space constitutes the joint allowable region of the mating control point. The joint allowable region defines the allowable combination relationship of the key dimension parameters of the blanking under joint variation conditions.

[0024] Specifically, for each mating control point, within the joint parameter space, the possible combinations of joint values ​​for the key blanking dimension parameters mapped to that control point are sequentially determined. The joint parameter space is a multi-dimensional space, with each dimension corresponding to a key blanking dimension parameter. Each point in the space represents a specific set of parameter combinations (i.e., a set of parameter values). During the determination, the spatial displacement residual vector and attitude residual vector corresponding to the joint value combination (calculated by the difference between the predicted and actual geometric responses obtained from the aforementioned single-parameter disturbance joint change and multi-parameter joint disturbance) are compared with the spatial displacement allowable deviation threshold and attitude allowable deviation threshold of the mating control point. The assembly consistency constraint rules are then used to determine whether the joint value combination meets the assembly consistency requirements. For joint value combinations that satisfy the assembly consistency constraint rules, the value ranges of each critical blanking dimension parameter corresponding to them in the joint parameter space are recorded and retained. The value ranges corresponding to all joint value combinations that meet the conditions constitute the joint allowable region of the mating control point, which is used to limit the allowable combination relationship of the critical blanking dimension parameters mapped to the mating control point under joint variation conditions. The residual vector of each joint value combination can be obtained one by one by discrete sampling or continuous scanning of the joint parameter space, and the allowable combinations are screened out according to the above determination steps, thereby forming the joint allowable region.

[0025] S6. Convert the joint allowed area into a size output restriction rule that the blanking device can execute, and perform the blanking operation under the constraint of the size output restriction rule to obtain multiple blanking parts; assemble the multiple blanking parts to form an assembly that meets the assembly consistency requirements.

[0026] Specifically, after obtaining the joint allowable area of ​​each mating control point, the joint allowable area is converted into dimensional output constraint rules executable by the cutting equipment. This includes: for each allowable combination within the joint allowable area, extracting the values ​​of each key cutting dimension parameter, and statistically analyzing the minimum and maximum values ​​of each key cutting dimension parameter across all allowable combinations; through comprehensive analysis of the parameter values ​​of all allowable combinations within the joint allowable area, determining the continuous parameter range covering all combinations for each key cutting dimension parameter, thus forming continuously executable dimensional output constraint rules for the cutting equipment to follow in actual operation. Then, the cutting equipment performs the cutting operation under the constraints of these dimensional output constraint rules, ensuring that the key cutting dimension parameters of each part are limited within the corresponding output rule range, thereby guaranteeing that each part meets the dimensional requirements of the joint allowable area. After the cutting operation, multiple cut parts are obtained, and the key dimension parameter combinations of each part conform to the assembly consistency constraints. Finally, the obtained multiple cut parts are assembled according to the assembly design requirements, relying on the aforementioned joint allowable area and dimensional output constraint rules to ensure that the relative positions and orientations between parts are within the allowable deviation range, thus forming an assembly that meets the assembly consistency requirements. This method ensures that the geometric accuracy and assembly performance of the final assembly meet design requirements, even with combined variations in key dimensional parameters during material preparation.

[0027] Example 2, as Figure 2 As shown, based on the same inventive concept as the method for precise control of blanking dimensions for assembly consistency in the foregoing embodiments, such as... Figure 2 As shown, this application provides a precise blanking dimension control system for assembly consistency. The system and method embodiments in this application are based on the same inventive concept. The system includes: The mapping relationship establishment module 11 is used to identify mating control points based on the assembly design data of the target assembly, determine the key dimensions of blanking associated with each mating control point, and establish the mapping relationship between the mating control points and the key dimensions of blanking. The geometric action path generation module 12 is used to determine the geometric action path of the blanking key dimension parameters along the geometric features of the design objects of each part in the assembly to the corresponding mating control point according to the mapping relationship. The geometric action path represents the transmission relationship and action link of the blanking key dimension parameters to the geometric response of the mating control point. The geometric response acquisition module 13 is used to apply single-parameter perturbations to each key dimension parameter of the material cutting according to the geometric action path, within the joint parameter space composed of the key dimension parameters of the material cutting mapped to the same mating control point, to obtain the predicted geometric response of the corresponding mating control point under the joint change of single-parameter perturbations; and to apply multi-parameter joint perturbations within the joint parameter space to obtain the actual geometric response of the corresponding mating control point. The assembly consistency constraint rule generation module 14 is used to establish nonlinear coupling constraint relationships between key material cutting dimension parameters mapped to the same mating control point based on the residual vector between the predicted geometric response and the actual geometric response, thereby forming assembly consistency constraint rules. The joint allowable area determination module 15 is used to determine the combination of each blanking key dimension parameter in the joint parameter space according to the assembly consistency constraint rules, and to determine the blanking key dimension parameter combination that satisfies the assembly consistency constraint rules as the joint allowable area, which is used to limit the allowable combination relationship of blanking key dimension parameters when the joint changes. The blanking execution and assembly module 16 is used to convert the joint allowed area into a size output restriction rule that the blanking equipment can execute, and to perform blanking operation under the constraint of the size output restriction rule to obtain multiple blanked parts; and to assemble the multiple blanked parts to form an assembly that meets the assembly consistency requirements.

[0028] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0029] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for precise control of blanking dimensions for assembly consistency, characterized in that, include: S1. Identify mating control points based on the assembly design data of the target assembly, determine the key dimensions of blanking associated with each mating control point, and establish a mapping relationship between the mating control points and the key dimensions of blanking. S2. Based on the mapping relationship, determine the geometric action path of the key dimension parameters of blanking to the corresponding mating control point along the geometric features of the design object of each part in the assembly. The geometric action path represents the transmission relationship and action link of the key dimension parameters of blanking to the geometric response of the mating control point. S3. Based on the geometric action path, in the joint parameter space composed of the key dimensions of the material cutting mapped to the same mating control point, apply single-parameter perturbation to each key dimension of the material cutting to obtain the predicted geometric response of the corresponding mating control point under the joint change of single-parameter perturbation; and apply multi-parameter joint perturbation in the joint parameter space to obtain the actual geometric response of the corresponding mating control point. S4. Based on the residual vector between the predicted geometric response and the actual geometric response, establish the nonlinear coupling constraint relationship between each key dimension parameter of the blanking that is mapped to the same mating control point, and form the assembly consistency constraint rule. S5. Based on the assembly consistency constraint rules, determine the combination of each blanking key dimension parameter in the joint parameter space, and determine the blanking key dimension parameter combination that satisfies the assembly consistency constraint rules as the joint allowable area, which is used to limit the allowable combination relationship of blanking key dimension parameters when the joint changes. S6. Convert the joint allowed area into a size output restriction rule that the blanking device can execute, and perform the blanking operation under the constraint of the size output restriction rule to obtain multiple blanking parts; assemble the multiple blanking parts to form an assembly that meets the assembly consistency requirements.

2. The method for precise control of material cutting dimensions as described in claim 1, characterized in that, The establishment of the mapping relationship includes: Based on the assembly design data of the target assembly, the geometric topological relationships between the geometric features of each part design object in the assembly, as well as the assembly constraint elements acting between different part design objects and their geometric features are obtained. Based on geometric topological relationships and assembly constraint elements, identify mating control points in the assembly. These mating control points are key position points that characterize the geometric spatial position and orientation of the part design object, including contact position control points, positioning datum position control points, and alignment datum position control points. For each mating control point, the dimensional parameters associated with its geometric spatial position and orientation are determined as the key dimensional parameters for blanking, and a many-to-many relationship is established between the mating control point and the key dimensional parameters for blanking.

3. The method for precise control of material cutting dimensions as described in claim 2, characterized in that, The determination of the geometric action path includes: Identify the geometric features to which each mating control point in the assembly depends, as well as the geometric features to which each critical dimension parameter of the blanking depends; Based on the mapping relationship between the control point and the key dimension parameters of the blanking, and according to the geometric topology and assembly constraint elements, the geometric interaction path between the geometric feature to which the key dimension parameter of the blanking is attached and the geometric feature to which its corresponding control point is attached is determined. The geometric interaction path is used to characterize the transmission relationship between each key dimension parameter of the blanking and the geometric spatial position and orientation of the control point.

4. The method for precise control of material cutting dimensions as described in claim 3, characterized in that, The acquisition of the predicted geometric response and the actual geometric response includes: For each mating control point, based on the mapping relationship between the mating control point and the key dimension parameters of the blanking, the key dimension parameters of the blanking mapped to the mating control point constitute a joint parameter space; Based on the geometric action path, in the joint parameter space, single-parameter perturbations are applied to each material cutting key dimension parameter mapped to the same mating control point, and the spatial displacement change vector and attitude change vector of the mating control point under each single-parameter perturbation condition are obtained. Based on the spatial displacement change vector and attitude change vector, the predicted geometric response of the corresponding control point under the joint change of single-parameter disturbance is obtained by weighted linear superposition. This includes the predicted spatial displacement change vector and the predicted attitude change vector, and the calculation formula is as follows: ； Where j is the control point number and i is the critical dimension parameter number for material cutting. This represents the total number of critical dimension parameters for blanking mapped to the mating control point j. and These are the predicted spatial displacement change vector and the predicted attitude change vector for the control point j, respectively. and These are the spatial displacement change vector and attitude change vector of control point j under the disturbance condition of the critical dimension parameter i during material feeding, respectively. The weighting coefficient corresponding to the critical dimension parameter of the i-th blank is calculated using the following formula: ； in, For the summation index, , and These are the control points j for the critical dimensions of the blanking process. The spatial displacement change vector and attitude change vector under disturbance conditions To match the scale adjustment factor of control point j, the scale adjustment factor is used to convert the attitude change vector into an equivalent quantity with the same dimensions as the spatial displacement change vector. Within the joint parameter space, multiple joint perturbations are applied simultaneously to the key dimensions of the material cutting that are mapped to the same mating control point to obtain the actual geometric response of the mating control point, including the actual spatial displacement change vector and the actual attitude change vector.

5. The method for precise control of material cutting dimensions as described in claim 4, characterized in that, The formation of the assembly consistency constraint rules includes: Based on the predicted spatial displacement change vector and predicted attitude change vector obtained from the predicted geometric response, and the actual spatial displacement change vector and actual attitude change vector obtained from the actual geometric response, the residual vector of the control point is calculated, and the residual vector includes the spatial displacement residual vector and the attitude residual vector. Based on the residual vector, the nonlinear coupling constraint relationship between the key dimensions of each blanking material mapped to the same mating control point is determined. Based on the nonlinear coupling constraint relationship and the allowable deviation thresholds of spatial displacement and attitude corresponding to the mating control point, assembly consistency constraint rules are formed.

6. The method for precise control of material cutting dimensions as described in claim 5, characterized in that, The determination of the joint permitted region includes: Within the joint parameter space, for each mating control point, the combination of key dimensions for blanking mapped to the same mating control point is determined according to the assembly consistency constraint rules based on the spatial displacement residual vector and attitude residual vector of the mating control point, as well as the spatial displacement allowable deviation threshold and attitude allowable deviation threshold. The set of values ​​corresponding to each combination of values ​​that satisfies the assembly consistency constraint rule in the joint parameter space constitutes the joint allowable region of the mating control point. The joint allowable region defines the allowable combination relationship of the key dimension parameters of the blanking under joint variation conditions.

7. A precise blanking dimension control system for assembly consistency, characterized in that, The system is used to implement the precise material cutting size control method according to any one of claims 1 to 6, the system comprising: The mapping relationship establishment module is used to identify mating control points based on the assembly design data of the target assembly, determine the key dimensions of blanking associated with each mating control point, and establish the mapping relationship between the mating control points and the key dimensions of blanking. The geometric action path generation module is used to determine the geometric action path of the blanking key dimension parameters along the geometric features of the design objects of each part in the assembly to the corresponding mating control point according to the mapping relationship. The geometric action path represents the transmission relationship and action link of the blanking key dimension parameters to the geometric response of the mating control point. The geometric response acquisition module is used to apply single-parameter perturbations to each critical dimension parameter of the material cutting process within a joint parameter space consisting of critical dimension parameters of the material cutting process mapped to the same mating control point, based on the geometric action path, to obtain the predicted geometric response of the corresponding mating control point under the joint change of single-parameter perturbations; and to apply multi-parameter joint perturbations within the joint parameter space to obtain the actual geometric response of the corresponding mating control point. The assembly consistency constraint rule generation module is used to establish nonlinear coupling constraint relationships between key material cutting dimension parameters mapped to the same mating control point based on the residual vector between the predicted geometric response and the actual geometric response, thus forming assembly consistency constraint rules. The joint allowable area determination module is used to determine the combination of each blanking key dimension parameter in the joint parameter space according to the assembly consistency constraint rules, and to determine the blanking key dimension parameter combination that satisfies the assembly consistency constraint rules as the joint allowable area, which is used to limit the allowable combination relationship of blanking key dimension parameters when the joint changes. The blanking execution and assembly module is used to convert the joint allowed area into dimensional output restriction rules that the blanking equipment can execute, and to perform blanking operations under the constraints of the dimensional output restriction rules to obtain multiple blanked parts; and to assemble the multiple blanked parts to form an assembly that meets the assembly consistency requirements.

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