CN110756641A

CN110756641A - Restraint method for full-profile springback compensation of automobile fender

Info

Publication number: CN110756641A
Application number: CN201911035762.4A
Authority: CN
Inventors: 郭涛; 涂小文
Original assignee: SAIC Volkswagen Automotive Co Ltd
Current assignee: SAIC Volkswagen Automotive Co Ltd
Priority date: 2019-10-29
Filing date: 2019-10-29
Publication date: 2020-02-07
Anticipated expiration: 2039-10-29
Also published as: CN110756641B

Abstract

The invention relates to the technical field of manufacturing of stamping dies, in particular to a restraint method for full profile springback compensation of an automobile fender, which comprises the following steps: step one, setting a preliminary constraint scheme by adopting a fixed boundary condition constraint mode; step two, calculating the restraint resilience of the fender, and judging whether the resilience restraint force of the restraint point meets a first preset requirement; thirdly, performing first adjustment and optimization on the constraint points based on the magnitude of the rebound constraint force; judging whether the rebound value of the fender meets a second preset requirement or not; fifthly, performing secondary adjustment and optimization on the constraint points based on the rebound quantity value; step six, taking the final constraint scheme meeting the requirements as a basic fixed boundary condition constraint mode, and performing iterative calculation of full profile springback compensation; and step seven, verifying the resilience constraint force of each constraint point after iterative computation. The invention has smaller rebound magnitude under smaller clamping force, and is beneficial to the accurate and reliable realization of full profile rebound compensation.

Description

Restraint method for full-profile springback compensation of automobile fender

Technical Field

The invention relates to the technical field of manufacturing of stamping dies, in particular to a restraint method for full-profile springback compensation of an automobile fender.

Background

The control of the dimensional accuracy of automobile fenders as important outer covers for mating with numerous parts on the body has been a major concern for the developers of stamping processes.

At present, a better method is to perform full profile springback compensation of the die based on the basic springback simulation condition of the part, wherein the selection of the constraint mode of the basic springback is very critical to the good and bad effect of the springback compensation.

At present, the introduction of full profile rebound compensation for the fender is provided, and the constraint method adopted in the basic rebound simulation stage is fewer and less.

In the prior art, the following two constraint methods exist in the constraint method adopted in the basic springback simulation stage in the full-profile springback compensation of the fender part.

The first constraint method refers to a commonly used idea in a local profile compensation method, that is, completely adopts RPS (Reference Point System) scheme specified by a part drawing for clamping. The following two problems exist with this constraint method:

1) when basic rebound evaluation is carried out, the constraint force is too large due to too much part constraint, so that the basic rebound of the part contains large additional elastic internal stress, the rebound in the state is distorted, and the part still needs large clamping force to be attached to the RPS point after rebound compensation. The spring back size of the parts will vary significantly after the RPS is released or displaced. Because the fixed point of the part during loading does not coincide with the RPS point of the part drawing, the large elastic stress in the part is redistributed, and the size problem is caused during loading;

2) the RPS points specified by the drawing are often different from key points of loading matching (the main characteristic line position of a fender matched with a door is often matched preferentially when loading is carried out), and finally, even if the parts are basically in place under the clamping of the RPS scheme, the matching of the parts still has a problem when loading.

The second constraint method uses an unconstrained gravity-free spring-back or a minimum clamping scheme that approximates the result of the free spring-back. There are also two problems with this constraint scheme:

1) the rebound value of the part under the constraint mode is possibly large, so that the required compensation value is large, and the reconstruction of the surface A cannot reach an ideal state;

2) the same as the first constraint method, the RPS point specified by the drawing is different from the key point matched with the loading.

Disclosure of Invention

The invention aims to provide a restraint method for full-profile springback compensation of an automobile fender, which solves the problem of distortion caused by the restraint method in the prior art on the full-profile springback compensation of the fender and improves the reliability and the accuracy of the full-profile springback compensation of the fender.

In order to achieve the purpose, the invention provides a restraint method for full profile springback compensation of an automobile fender, which comprises the following steps of:

step one, setting a preliminary constraint scheme by adopting a fixed boundary condition constraint mode;

step two, under the preliminary restraint scheme, calculating the restraint resilience of the fender, judging whether the resilience restraint force of the restraint point meets a first preset requirement, if not, entering step three, and if so, entering step four;

thirdly, adjusting and optimizing the constraint points for the first time based on the magnitude of the rebound constraint force until the rebound constraint force meets a first preset requirement, setting the first time as an optimization constraint scheme, and calculating the constraint rebound of the fender under the first time optimization constraint scheme;

step four, judging whether the rebound value of the fender meets a second preset requirement, if not, entering step five, and if so, entering step six;

fifthly, adjusting and optimizing the constraint points for the second time based on the rebound quantity value until the rebound quantity value meets a second preset requirement, and setting the rebound constraint force to be a second optimization constraint scheme when the rebound constraint force meets the first preset requirement;

step six, taking the final constraint scheme meeting the requirements as a basic fixed boundary condition constraint mode, and performing iterative calculation of full profile springback compensation;

and step seven, verifying the resilience constraint force of each constraint point after iterative computation, judging whether the resilience constraint force meets a third preset requirement, returning to the step three to perform adjustment and optimization if the resilience constraint force does not meet the third preset requirement, and ending if the resilience constraint force meets the third preset requirement.

In one embodiment, before the first step, the placing direction of the fender is defined according to the installation direction of the fender on the vehicle body, and the placing direction is consistent with the gravity condition in the loading state;

and in the second step to the sixth step, the algorithm for calculating the restraint rebound of the fender comprises a gravity action factor.

In one embodiment, in the first step: setting a preliminary constraint scheme based on a 3-2-1 principle, wherein the 3-2-1 principle is that 6 constraint points are selected at positioning points and loading matching points, and the 6 constraint points comprise 1X-direction constraint point, 2Z-direction constraint points and 3Y-direction constraint points.

In an embodiment, in the first step, the setting positions of the 6 constraint points are:

1X-direction constraint point is arranged on the periphery of the flanging profile of the A column;

2Z-direction constraint points are arranged on the left side and the right side of the center of gravity of the fender;

and 3Y-direction constraint points are selected and set according to the positions of the positioning points.

In one embodiment, the set position of the constraint point is matched with the main characteristic line.

In an embodiment, in the second step, the first preset requirement of the rebound restraint force further includes:

the total resilience constraint force of all the Z-direction constraint points balances and counteracts gravity;

the resilience constraint force of each Z-direction constraint point is in the positive Z direction;

and the resilience constraint force of each X-direction constraint point and each Y-direction constraint point is less than or equal to a first preset constraint force.

In an embodiment, in the third step, the first adjustment and optimization is performed, the force arm of the control constraint point is adjusted according to the moment balance principle under the gravity condition, and the resilience constraint force of the corresponding constraint point is adjusted and optimized.

In one embodiment, in the third step, the optimization is adjusted for the first time, and the position of the Z-direction constraint point is moved by controlling the moment arm of the Z-direction constraint point relative to the gravity center, so as to control the rebound constraint force of the Y-direction constraint point and/or the X-direction constraint point.

In an embodiment, in the fourth step, the second preset requirement of the rebound value further includes: the rebound value of the A surface of the automobile fender is smaller than or equal to a first preset rebound value.

In an embodiment, in the fifth step, the second tuning optimization includes the following steps:

and in the area where the rebound value does not meet the second preset requirement, selecting a reference positioning point or a position adjacent to the reference positioning point, and adding a Y-direction constraint point.

in the area where the rebound quantity value does not meet the second preset requirement, selecting a plurality of Y-direction constraint points at corresponding positions where the rebound quantity changes from large to small;

respectively calculating the restraint resilience of the fender under the corresponding restraint scheme;

and selecting a Y-direction constraint point with the rebound constraint force and the rebound magnitude meeting the preset requirements as a newly added Y-direction constraint point.

In an embodiment, in the seventh step, the resilience constraint force of the constraint point after the compensation iteration is verified, and the constraint mode is fixed based on the constraint mode.

In an embodiment, in the seventh step, the resilience constraint force of the constraint point after the compensation iteration is verified, and the constraint mode is a real measurement constraint mode defined according to the part positioning point system scheme.

In an embodiment, in the seventh step, the third preset requirement further includes:

and after the iterative calculation of full profile springback compensation, the springback constraint force of each X-direction constraint point and each Y-direction constraint point is less than or equal to a first preset constraint force.

and after the iterative calculation of full profile springback compensation, the springback constraint force of each X-direction constraint point and each Y-direction constraint point is less than or equal to a second preset constraint force.

According to the restraint method for the full-profile springback compensation of the automobile fender, the state of smaller springback value under smaller clamping force is achieved by controlling and optimizing the springback restraint force and the springback value under the restraint condition, and the accurate and reliable realization of the full-profile springback compensation is facilitated.

Drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description of the embodiments with reference to the accompanying drawings in which like reference numerals denote like features throughout the several views, wherein:

FIG. 1 discloses a flow chart of a restraint method for full profile springback compensation of a fender according to an embodiment of the invention;

FIG. 2a discloses a product RPS definition diagram of a fender part a according to a first embodiment of the invention;

fig. 2b discloses a schematic view of a preliminary restraint solution for a fender part a according to a first embodiment of the invention;

FIG. 3a discloses a schematic diagram of a basic FBC constraint mode after compensation iteration of a fender part a of the automobile according to the first embodiment of the invention;

FIG. 3b discloses a schematic view of the true grip constraint of a fender part a according to the RPS of the part after iteration of compensation according to the first embodiment of the invention;

FIG. 4a discloses a product RPS definition diagram of a fender part b according to a second embodiment of the invention;

fig. 4b discloses a schematic view of a preliminary restraint solution for a fender part b according to a second embodiment of the invention;

FIG. 5a discloses a first tuned optimised initial state moment diagram for a fender part b according to a second embodiment of the invention;

fig. 5b discloses a moment diagram of a first adjustment optimization of the fender part b according to the second embodiment of the invention;

fig. 6 discloses a schematic view of the pre-adjusted and post-adjusted positions of a first-time adjustment optimization of a fender part b according to a second embodiment of the invention;

FIG. 7 shows a schematic view of the profile and profile simulated springback acquisition point position before second tuning optimization of a fender part b according to a second embodiment of the invention;

fig. 8 discloses a schematic view of an adjustment process for a second adjustment optimization of a fender part b according to a second embodiment of the invention;

FIG. 9 shows a schematic view of a second tuned optimized profile and contour simulation rebound collection point location for a fender part b according to a second embodiment of the invention;

FIG. 10a discloses a schematic diagram of the iterative base FBC constraint of a fender part b according to a second embodiment of the invention;

FIG. 10b discloses a schematic view of the true grip constraint of a fender part b according to the part RPS after iteration of compensation according to a second embodiment of the invention;

fig. 11 discloses a schematic view of a final restraining solution for a fender part b of a vehicle according to a second embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a constraint method for an automobile fender in full-profile rebound compensation, which can realize reliable and accurate full-profile rebound compensation for the fender and can be called as a 6+ X degree of freedom constraint method.

As a preferred embodiment, the full profile rebound compensation provided by the invention can be realized in the Autoform software, so the following technical scheme can be completed in the Autoform software. The auto form is finite element analysis software, in the finite element analysis, an analysis object is to be discretized into a finite number of meshes, and points forming each mesh are mesh nodes.

Fig. 1 discloses a flow chart of a restraint method for compensating the springback of the full profile of the automobile fender according to an embodiment of the invention, and the technical solution of the invention is described in detail below with reference to the embodiment shown in fig. 1.

Step one, setting a preliminary constraint scheme.

Setting up preliminary restraint scheme, at first need define the direction of placing of fender part.

In the preferred embodiment of the invention, the calculation of the restraint resilience of the fender is the restraint resilience with gravity, and the algorithm for calculating the restraint resilience of the fender comprises a gravity action factor, so that when the placement direction of the fender part is defined, the installation direction of the part on the vehicle body is strictly followed, and the condition that the gravity condition of a single piece of the fender part is completely consistent with that of the vehicle body in the loading state is ensured.

The coordinate system is a vehicle body coordinate system, and the coordinate Z direction is defined as the vehicle height direction and is positive upwards, the Y direction is the vehicle width direction and is positive rightwards, the X direction is the vehicle length direction and is positive backwards.

In the preferred embodiment of the present invention, a Fixed Boundary Condition (FBC) constraint mode is adopted.

The FBC constraint mode refers to the constraint of grid nodes of the finite element model, one or more directions of X direction, Y direction and Z direction are respectively selected to be set as fixed constraints, the displacement of the node in the selected direction is limited, and the node is only allowed to displace in other directions.

Further, in the FBC constraint mode, a preliminary constraint scheme can be set based on the 3-2-1 principle.

The 3-2-1 principle refers to that 6 freedom degree constraint points are selected preliminarily. Each constraint direction set on a point is calculated as a constraint point, which is called constraint point for short.

The selected position of the constraint Point mainly considers the key points of the Reference Point System (RPS) locating Point and the loading matching Point.

Constraint definition is carried out based on a 3-2-1 principle, and the 6-degree-of-freedom constraint points comprise 1X-direction constraint point, 2Z-direction constraint points and 3Y-direction constraint points.

As a preferred embodiment, the arrangement positions of the 6 constraining points are as follows:

1X-direction constraint point arranged at the periphery of the A-pillar flanging contour and used for controlling the contour clearance between the fender and the door panel;

the 2Z-direction constraint points are arranged on the left side and the right side of the gravity center of the fender part and are used for balancing and offsetting the action of gravity, and meanwhile, the fender part can be prevented from rotating in an XZ plane due to the moment balance problem;

the 3Y-direction constraint points are selected with reference to the RPS positions.

Regarding the arrangement position of the above-described constraint point, the main characteristic line is preferentially matched in consideration of vehicle body matching.

Therefore, it is preferable to provide the X-direction, Y-direction, and Z-direction restraining points at the same time at the position of the a-plane on the main feature line of the fender component, which is about 2mm from the a-pillar contour.

And step two, under the preliminary constraint scheme, calculating the constraint resilience of the fender, and judging whether the resilience constraint force of the constraint point meets a first preset requirement.

And if the resilience constraint force of the constraint point does not meet the first preset requirement, the step III is carried out, and if the first preset requirement is met, the step IV is carried out.

Preferably, the calculated restraint rebound is a restraint rebound of the fender component under the restraint scheme with gravity. The algorithm for calculating the restraint rebound of the fender comprises a gravity action factor.

Based on the preliminary restraint scheme that 3-2-1 principle set up, fender part is similar to free restraint basically, will satisfy above-mentioned resilience constraining force requirement to most fender parts, promptly first preset requirement.

The first preset requirement of the rebound restraint force refers to the requirement of the rebound restraint force on each restraint point after the rebound is restrained. The first preset requirement specifically includes the following steps:

the total resilience restraining force of all the Z-direction restraining points balances and counteracts gravity;

The first preset restraining force may be preset according to actual needs, and as a preferred embodiment, the first preset restraining force is 3N, and the rebound restraining force of each of the X-direction restraining point and the Y-direction restraining point is less than or equal to 3N.

And step three, performing first adjustment optimization on the constraint points based on the magnitude of the resilience constraint force until the resilience constraint force meets a first preset requirement, and setting the first optimization constraint scheme.

In the second step, if the resilience constraining force of the constraining point does not meet the first preset requirement, the third step is carried out, and the constraining point is adjusted and optimized for the first time based on the resilience constraining force.

The first adjustment and optimization is to adjust and control the moment arm of the constraint point according to the moment balance principle under the gravity condition, and adjust and optimize the resilience constraint force of the constraint point.

The principle of moment balance under gravity is as follows:

taking the example of adjusting and optimizing the Y-direction constraint point, the Z-direction force and the Y-direction force provide reactive moments with respect to the center of gravity. In order to ensure moment balance, the moment arm of the Z-direction constraint point relative to the gravity center is reduced, and the rebound constraint force of the Y-direction constraint point is reduced.

Therefore, the position of the Z-direction constraint point can be moved by controlling the arm of the Z-direction constraint point relative to the gravity center, and the rebound constraint force of the Y-direction constraint point can be controlled.

The mathematical relationship of the moment balance principle under gravity is as follows:

taking the adjustment and optimization of the Y-direction constraint point as an example, Fz is a total Z-direction force counteracting gravity G, Fz is G, Fy is a Y-direction force of the Y-direction constraint point, Lz is a Z-direction force arm of the Z-direction constraint point, and Ly is a Y-direction force arm of the Y-direction constraint point.

The moment generated by the Z-direction force Fz needs to be balanced with the counter moment of the Y-direction force Fy with respect to the center of gravity, and there is a relationship Fz · Lz ═ Fy · Ly.

Therefore, by controlling the force arm Lz, the Y-direction force Fy can be controlled.

The specific numerical value of the Z-direction moment arm Lz can be adjusted and determined through repeated tests, and statics analysis and solving can be carried out through related software and algorithms.

The method for adjusting and optimizing the X-direction constraint points is the same as that of the Y-direction constraint points. Since the X-direction constraint point is generally fixedly arranged at the position of the feature line, the X-direction constraint point does not need to be adjusted in a general situation.

And moving the position of the Z-direction constraint point according to the method to ensure that the X-direction constraint force and the Y-direction constraint force of each constraint point meet the requirement.

And step four, judging whether the rebound value of the fender meets a second preset requirement or not.

In the second step and the third step, if the resilience constraint force of the constraint point meets the first preset requirement, the fourth step is carried out, and whether the resilience value of the fender meets the second preset requirement is judged. And if the rebound value of the fender does not meet the second preset requirement, entering a fifth step, and if the second preset requirement is met, entering a sixth step.

Set up the collection point of several resilience value on the fender, the resilience value and the resilience distribution homogeneity of each collection point of inspection require the resilience value of fender to satisfy the second and predetermine the requirement to the degree of difficulty that the too big A face of fender that increases of compensation volume that kick-backs even leads to the A face of fender to reconstruct fails.

Acquisition points of the rebound magnitude, which may include, but are not limited to, tie points, are typically located on both the profile and the contour.

The second preset requirement is the requirement for the rebound value of the automobile fender after rebound.

As a preferred embodiment, the second preset requirement is that the rebound value of the a surface of the automobile fender is smaller than or equal to the first preset rebound value. The A surface generally refers to a class A curved surface, and can be considered as the outer surface of the automobile fender body.

The first preset rebound value can be preset according to actual needs, and as a preferred embodiment, the first preset rebound value is 3 mm.

And (4) checking the resilience value and the resilience distribution uniformity of each detection point, wherein the resilience value of the surface A is required to be within 3 mm.

And fifthly, adjusting and optimizing the constraint points for the second time based on the resilience value until the resilience value meets a second preset requirement, and setting the resilience constraint force to be a second optimization constraint scheme when the resilience constraint force meets the first preset requirement.

In the fourth step, if the rebound value of the fender does not meet the second preset requirement, the step five is carried out, and the constraint point is adjusted and optimized for the second time based on the rebound constraint force.

And when the rebound value is too large and does not meet the second preset requirement, the constraint point needs to be adjusted and optimized for the second time.

In a preferred embodiment, the rebound value of the A surface of the automobile fender is larger than 3mm, and the rebound value is considered to be too large.

And the second adjustment optimization is divided into the following two situations according to the area where the rebound value which does not meet the requirement appears:

in the first situation, the rebound value is reduced by adopting an optimization process, the method of the optimization process comprises but is not limited to optimizing the working angle of the side flanging wedge, and the like, and the adjustment optimization mode is mainly suitable for the situation that the rebound value which does not meet the requirement appears in the A column area;

in the second case, where a new constraint point is added in the region where the unsatisfactory springback value occurs, the tuning optimization is mainly adapted to the case where the unsatisfactory springback value occurs in front of the fender part. This situation may be due to the resilient torsion of the fender component, making it difficult to effectively reduce the magnitude of the spring back through process optimization.

In a second case, the second adjustment and optimization further includes a step of, on the basis of the constraint scheme formed by the first adjustment and optimization, selecting a reference point location (RPS point) or a position adjacent to the RPS point in a region where the rebound value does not meet a second preset requirement, and adding a Y-direction constraint point.

And calculating the resilience of the fender part in the constraint state of the second adjustment optimization, and checking whether the resilience value meets a second preset requirement and whether the resilience constraint force meets a first preset requirement. In a preferred embodiment, the rebound value of the surface A is less than or equal to 3mm, and the rebound restraining force of each X-direction restraining point and each Y-direction restraining point is less than or equal to 3N.

If the requirement of rebound restraining force and rebound value is not met by adding a Y-direction restraining point, the restraining point is adjusted and tried by moving as follows:

and moving the selected position of the Y-direction constraint point from the area with larger rebound value to the area with smaller rebound value. For example, if the calculated maximum value of the springback is 6mm, positions with springback values of 5mm, 4mm, 3mm, 2mm and 1mm are sequentially selected as Y-direction constraint points, constraint springback of the wing panel under each of the Y-direction constraint points is calculated, and a Y-direction constraint point satisfying requirements for both the springback amount and the springback constraint force is selected as a new Y-direction constraint point to form a new constraint scheme.

And after the optimization and adjustment, the constraint mode meeting the first preset condition and the second preset condition is used as a basic FBC constraint mode of iterative compensation calculation.

And step six, taking the final constraint scheme meeting the requirements as a basic fixed boundary condition constraint mode, and performing iterative calculation of full profile springback compensation.

The constraint scheme which meets the requirements after optimization and adjustment or directly meets the requirements without adjustment is used as a basic FBC constraint mode to participate in iterative calculation of full profile springback compensation.

And verifying whether the resilience restraining force of each restraining point meets a third requirement again aiming at the restraining scheme that the resilience value of each restraining point meets the requirement after the iterative computation of the full profile resilience compensation is participated.

Optionally, the binding force of each binding point is verified in the following two binding modes:

one is a basic FBC constraint mode for iterative compensation, that is, a final constraint scheme meeting requirements is formed after performing first adjustment optimization and second adjustment optimization on constraint points in the above steps.

The other is a Real Measurement constraint mode (Real Measurement) defined according to the part RPS scheme, the Real Measurement constraint mode is a constraint mode set in the rebound calculation, an RPS point defined by the part RPS scheme is used as a constraint point, the constraint mode adopts a simulation chuck to constrain the part, the rebound in the constraint state is analyzed, and the rebound calculation is carried out.

And determining whether the magnitude of the rebound restraining force of each restraining point after the rebound compensation iteration meets a third preset requirement or not through the restraining mode.

For the real measurement constraint mode, the X-direction force and the Y-direction force of the positioning pin are checked and confirmed.

The third preset requirement specifically includes the following two requirements for rebound restraint force:

for an automobile fender part which has a small springback amount before compensation, namely does not need to pass through the step five and is not subjected to secondary adjustment and optimization, the springback constraint force of each X-direction constraint point and each Y-direction constraint point is required to be less than or equal to a first preset constraint force in the two constraint modes. As a preferred embodiment, the first preset restraining force is 3N, and the rebound restraining force of each of the X-direction restraining force and the Y-direction restraining point is 3N or less.

And for the automobile fender part which has overlarge springback amount caused by springback torsion before compensation, namely needs to be subjected to secondary adjustment and optimization through the fifth step, the requirement is that the springback constraint force of each X-direction constraint point and each Y-direction constraint point is smaller than or equal to a second preset constraint force in the two constraint modes. As a preferred embodiment, the second preset restraining force is 5N, and the rebound restraining force of each of the X-direction restraining force and the Y-direction restraining point is 5N or less.

And if the resilience constraining force does not meet the third preset requirement, locally adjusting and optimizing the constraining point, wherein the adjusting mode refers to the third step and the fifth step until the constraining point finally meets the requirement.

The method of rebound restraint according to the present invention is further described and explained below in conjunction with two specific fender parts, namely, fender part a and fender part b. The full profile rebound compensation can be realized in the auto form software, so the following operations (setting and calculation) can be completed in the auto form software.

The fender part a of a certain vehicle type has high rigidity and small opening at the lamp opening.

Step one, a preliminary constraint scheme is set by adopting a fixed boundary condition constraint mode.

The part placement direction is defined. The method is characterized in that the method strictly follows the installation direction of parts on a vehicle body to ensure that the gravity condition of a single piece of the fender part is completely consistent with that of a loaded fender part.

The constraint mode adopts an FBC constraint mode.

Setting a preliminary constraint scheme based on a 3-2-1 principle.

Fig. 2a discloses a product RPS definition diagram of a fender part a according to a first embodiment of the present invention, and the RPS scheme of the fender part a is shown in fig. 2a, where the RPS points of the fender part a include 1 RPS _ FX point, 3 RPS _ FY points, 2 RPS _ FZ points, and 5 RPS _ FY points. The coordinate system is a vehicle body coordinate system.

And 6 constraint points are preliminarily selected, and constraint definition is carried out based on a 3-2-1 principle, wherein the constraint points comprise 1X-direction constraint point, 2Z-direction constraint points and 3Y-direction constraint points.

Fig. 2b discloses a schematic diagram of a preliminary restraint scheme of the fender part a according to the first embodiment of the invention, wherein the 6 restraint points comprise 1X-direction restraint point FBC _ X1, 2Z-direction restraint points FBC _ Z1 and FBC _ Z2, and 3Y-direction restraint points FBC _ Y1, FBC _ Y2 and FBC _ Y3, and the arrangement positions are as shown in fig. 2 b.

In consideration of the priority of matching the main characteristic line when matching the vehicle body and the control of the contour clearance between the fender and the door panel, an X-direction restraining point FBC _ X1 and a Y-direction restraining point FBC _ Y1 are provided at the A-plane position on the main characteristic line of the fender component, which is about 2mm from the A-pillar contour.

And 2Z-direction constraint points are arranged on two sides of the gravity center of the part.

And defining and selecting a flanging fillet position near the front RPS point of the front cover area by referring to the RPS point, and setting a first Z-direction constraint point FBC _ Z1.

To ensure that the fender component does not rotate and that the component does not rotate in the XZ plane due to moment balance problems, a point on the other side of the center of gravity of the upper portion of the component is selected as a second Z-direction restraining point FBC _ Z2.

The distribution of the 2Y-direction constraint points is dispersed as much as possible with reference to the positions of the RPS points, where one of the Y-direction constraint points is located at the RPS point RPS _ FY located on the lower side of the a pillar and is defined as FBC _ Y2, and the other Y-direction constraint point is located at the RPS point RPS _ FY located in the front bumper region and is defined as FBC _ Y3.

In the embodiment, the rebound with gravity constraint of the fender part a under the preliminary constraint scheme is calculated, and the first preset constraint force is 3N.

The rebound restraining force at the restraining point calculated in this example is shown in table 1, where a positive value represents rebound outward of the vehicle body. And the requirement that the X-direction force of the X-direction constraint point and the Y-direction force of the Y-direction constraint point are within 3N is met, the constraint point does not need to be adjusted, and the step three and the step four are not performed.

TABLE 1 Resilience restraint force calculated under preliminary restraint scheme (part a)

And arranging a plurality of acquisition points of the rebound values on the fender, and checking the rebound values and the distribution uniformity of the rebound values of all the points. In this embodiment, the second preset requirement is that the rebound value of the a-plane is within 3mm, so as to prevent the difficulty of reconstruction of the a-plane from being increased by too large rebound compensation amount, and even cause reconstruction failure of the a-plane.

In this embodiment, through inspection, the maximum rebound value of the a surface of the fender part a is within 3mm, adjustment and optimization are not required, the fifth step is not performed, and the sixth step is performed.

As the initial constraint scheme meets the conditions of the rebound constraint force and the rebound value, the initial constraint scheme is the final constraint scheme meeting the requirements and is used as a basic FBC constraint mode to carry out iterative calculation of the full profile rebound compensation.

And step seven, verifying the resilience constraint force of each constraint point after iterative computation, and judging whether the resilience constraint force meets a third preset requirement.

A plurality of acquisition points of resilience values are arranged on the fender part a, the resilience constraint force of the constraint points after the compensation iteration is verified, and the following two constraint modes can be adopted: a base FBC constraint mode and a true measurement constraint mode defined according to the part RPS scheme.

For a part with a small rebound amount before compensation, that is, a part without performing the second optimization adjustment of the restraining point based on the rebound amount, the third preset requirement is that, in the two restraining manners, the rebound restraining force of each of the X-direction restraining point and the Y-direction restraining point is less than or equal to the first preset restraining force. In this embodiment, the third preset requirement is that the constraining forces of the X-direction constraining point and the Y-direction constraining point in the two constraining manners both satisfy equal to or less than 3N.

The fender part a in the embodiment is in this case, and therefore, it is necessary to satisfy that the restraining force of each of the X-direction restraining point and the Y-direction restraining point satisfies ≦ 3N in both the two restraining manners.

And (3) calculating the springback iterative compensation, checking and adjusting based on the constraint force, and confirming that the constraint force of each constraint point meets the requirement under the two constraint modes aiming at the file with the compensated springback value meeting the requirement.

Fig. 3a discloses a schematic diagram of a basic FBC constraint mode after compensation iteration of the fender part a according to the first embodiment of the invention, wherein each constraint point comprises 1X-direction constraint point FBC _ X1, 2Z-direction constraint points FBC _ Z1 and FBC _ Z2, and 3Y-direction constraint points FBC _ Y1, FBC _ Y2 and FBC _ Y3, and the arrangement positions of the points are as shown in fig. 3 a. Under the constraint scheme shown in fig. 3a, the calculated rebound restraining forces for each restraining point after the compensation iteration are shown in table 2, wherein positive values represent rebound outward of the vehicle body.

The X-direction force and the Y-direction force of each constraint point both satisfy less than or equal to 3N.

TABLE 2 Compensation of the Resilience restraint calculated under the iterative Foundation FBC restraint mode (part a)

Fig. 3b discloses a schematic diagram of the actual clamping constraint manner of the automobile fender part a according to the RPS after compensation iteration, wherein each constraint point comprises a constraint point Clamp _1, a constraint point Clamp _2, a constraint point Clamp _3, a constraint point Clamp _4, a constraint point Clamp _5, a constraint point Clamp _6, a constraint point Clamp _7, a constraint point Clamp _8, a positioning pin1 and a positioning pin2, and the arrangement positions of the constraint points are shown in fig. 3 b. Under the constraint scheme shown in fig. 3b, the calculated rebound restraining forces for each restraining point after the compensation iteration are shown in table 3, where positive values represent rebound outward of the body.

And (4) the X-direction force and the Y-direction force of each constraint point meet the condition that the number is less than or equal to 3N, and the constraint method is ended.

TABLE 3 Compensation of the calculated rebound restraint force after iteration under the true measurement restraint scheme defined by the part RPS scheme (part a)

The method of restraining the rebound according to the present invention will be further explained and explained by taking the fender part b as an example.

The fender part b of a certain vehicle type has poor part rigidity and a large opening at a lamp holder.

The constraint mode adopts an FBC constraint mode.

Setting a preliminary constraint scheme based on a 3-2-1 principle.

Fig. 4a discloses a product RPS definition diagram of a fender part b according to a second embodiment of the present invention, and the RPS scheme of the fender part b is shown in fig. 4a, where the RPS points of the fender part b include 1 RPS _ FX point, 3 RPS _ FY points, 2 RPS _ FZ points, and 5 RPS _ FY points. The coordinate system is a vehicle body coordinate system.

Fig. 4b discloses a schematic diagram of a preliminary restraint scheme of a fender part b according to a second embodiment of the invention, wherein 6 restraint points comprise 1X-direction restraint point FBC _ X1, 2Z-direction restraint points FBC _ Z1 and FBC _ Z2, and 3Y-direction restraint points FBC _ Y1, FBC _ Y2 and FBC _ Y3, and the arrangement positions are as shown in fig. 4 b.

And selecting the position of a flanging fillet near the front RPS of the front cover area by referring to the RPS definition, and setting a first Z-direction constraint point FBC _ Z1.

To ensure that the part does not rotate, and to ensure that the part does not rotate in the XZ plane due to moment balance problems, a point on the other side of the center of gravity of the upper portion of the part is selected as a second Z-direction constraint point FBC _ Z2.

The distribution of the 2Y-direction constraint points is distributed as much as possible with reference to the RPS positions, and one of the Y-direction constraint points is located at the RPS point RPS _ FY located below the a-pillar and is defined as FBC _ Y2, and the other is located at the RPS point RPS _ FY located in the front bumper region and is defined as FBC _ Y3.

In the embodiment, the rebound with gravity constraint of the fender part b under the preliminary constraint scheme is calculated, and the first preset constraint force is 3N.

The restraining force at the restraining point was calculated in this example as shown in table 4, where a positive value represents rebound outward of the vehicle body.

The Y-direction restraining force at restraining point FBC _ Y1 and restraining point FBC _ Y2 exceeds 3N. Wherein positive values represent rebound outward of the vehicle body. And (5) adjusting and optimizing the constraint points for the first time, and entering the step three.

TABLE 4 Resilience restraint force calculated under preliminary restraint scheme (part b)

And step three, carrying out first adjustment and optimization on the constraint points based on the magnitude of the rebound constraint force.

And adjusting and optimizing the constraint points for the first time based on the magnitude of the resilience constraint force, adjusting and controlling the moment arms of the constraint points according to the moment balance principle under the gravity condition, and adjusting and optimizing the resilience constraint force of the constraint points.

Fig. 5a and 5b disclose an initial state of the first adjustment optimization and a moment diagram of the adjustment process of the fender part b according to the second embodiment of the invention, as shown in fig. 5a and 5b, and the adjustment principle of the first adjustment optimization is explained by taking the adjustment of the Z-direction constraint point FBC _ Z2 as an example.

The Z-direction force Fz and the Y-direction force Fy provide counteracting moments with respect to the center of gravity. To ensure moment balance, the Z-direction moment arm Lz of the Z-direction constraint point FBC _ Z2 relative to the gravity center is reduced, and the constraint force of the Y-direction constraint point is reduced.

Fz is the total Z-direction force that counteracts the gravitational force G, and the moment generated by the Z-direction force Fz requires a counter moment balance of the Y-direction force at the Y-direction constraint point with respect to the center of gravity.

In this embodiment, as shown in fig. 5a and 5b, the initial Z-direction force arm Lz1 is larger, which results in that the Y-direction force Fy1 required by the Y-direction constraint point FBC _ Y2 is larger than 3N, and the Z-direction force arm Lz1 is reduced to the Z-direction force arm Lz2 with a certain value by adjusting the position of the Z-direction constraint point FBC _ Z2, so that the reduction of the Y-direction force Fy2 of the Y-direction constraint point FBC _ Y2 can be satisfied, and the requirement that the rebound constraint force is less than or equal to 3N is satisfied.

At this time, the Y-direction force of Y-direction constraint point FBC _ Y1 was 1.2N, and the Y-direction force of Y-direction constraint point FBC _ Y2 was-1.1N.

The adjusted restraining point positions are shown in fig. 6, and fig. 6 discloses a schematic diagram of the before-after-adjustment positions of the first adjustment optimization of the fender part b according to the second embodiment of the present invention, where the hollow point positions are the arrangement positions of the Z-direction restraining point FBC _ Z1 and the Z-direction restraining point FBC _ Z2 before adjustment, and the solid point positions are the arrangement positions of the Z-direction restraining point FBC _ Z1, the Z-direction restraining point FBC _ Z2, the Y-direction restraining point FBC _ Y1, the Y-direction restraining point FBC _ Y2, the Y-direction restraining point FBC _ Y3, and the X-direction restraining point FBC _ X1 after adjustment.

After the first adjustment and optimization, the rebound with the gravity constraint under the constraint scheme after the adjustment and optimization is calculated, and the rebound constraint force of each constraint point after the adjustment and optimization is shown in table 5, wherein a positive value represents the rebound towards the outside of the vehicle body.

And (5) the resilience constraint force of each constraint point meets the requirement, and the step four is carried out.

TABLE 5 Resilience restraint force calculated after first adjustment optimization (part b)

And arranging a plurality of acquisition points of the rebound values on the fender, and checking the rebound values and the distribution uniformity of the rebound values of all the points. In this embodiment, the second preset requirement is that the rebound value of the a-plane is within 3mm, so as to prevent the difficulty of reconstruction of the a-plane from being increased by too large compensation amount of rebound, and even cause reconstruction failure of the a-plane.

Fig. 7 shows a schematic view of the position of the profile and contour simulation rebound collection points of the automobile fender part b before the second adjustment optimization according to the second embodiment of the invention, and the arrangement positions of the rebound collection points M1-M18 are shown in fig. 7.

The maximum rebound value of the surface a of the fender part b in this example was-11 mm, and as shown in table 6, table 6 shows the rebound values of the profile and the contour simulation rebound collection point before the second adjustment optimization, where a positive value represents the rebound toward the outside of the vehicle body.

And C, the rebound value of the fender does not meet a second preset requirement, and the step V is carried out. It is clear that a direct compensation of such a rebound amount is difficult to achieve.

TABLE 6 Resilience values of profile and contour simulation Resilience acquisition points before second adjustment optimization

Point location	Value/mm	Point location	Value/mm
				M1	-11.070	M10	-2.602
M2	-10.140	M11	-2.926
				M3	-6.959	M12	-1.489
M4	-5.011	M13	-0.025
				M5	-4.401	M14	0.094
M6	-6.469	M15	-0.057
				M7	-5.077	M16	-0.002
M8	-2.018	M17	-0.348
				M9	-5.023	M18	0.115

And fifthly, performing secondary adjustment and optimization on the constraint points based on the rebound quantity value.

The main reason for the large rebound amount of the fender part b is that a gap is formed in the headlight at the front part of the part, the rigidity is weak, the part rebounds in a torsion mode, and belongs to the second situation of the fifth step.

Fig. 8 is a schematic diagram illustrating an adjustment process of the second adjustment and optimization of the fender part b according to the second embodiment of the present invention, where the selection and adjustment of the constraint points are as shown in fig. 8, and on the basis of the constraint scheme formed by the first adjustment and optimization, the constraint points are added to the region with a larger rebound value, a Y-direction constraint point FBC _ Y4 is added to the vicinity of the RPS point in the region, and the constraint rebound of the fender part b in the above-mentioned constraint state is calculated.

Through verification, under the condition that a Y-direction constraint point FBC _ Y4 is added, although the rebound value of the acquisition point meets the second preset requirement, the rebound constraint force of the constraint point does not meet the first preset requirement and exceeds 3N. Further adjustments to the Y-direction constraint points are therefore required.

Moving the Y-direction constraint point FBC _ Y4 from a region with a larger rebound value to a region with a smaller rebound value, wherein the arrow direction of FIG. 8 is the moving direction of the Y-direction constraint point FBC _ Y4 when the adjustment is performed, the distribution of the rebound values shown by the dotted lines is respectively-9 mm, -7mm, -5mm, -4mm, -3mm, the rebound values of the Y-direction constraint point FBC _ Y4 at various positions are respectively calculated, when the movement is performed to the position with the rebound value of-7 mm, the maximum rebound value of the Y-direction constraint point FBC _ Y4 of the part b is calculated to be-1.7 mm, the first preset requirement is met, the rebound value of the A surface is less than or equal to 3mm, the maximum restraint force of the X direction and the Y direction is 2.4N, the second preset requirement is met, and the rebound force is less than or equal to 3N, so as to form a final constraint.

Fig. 9 shows a schematic diagram of the position of the simulated springback collection points of the second-time adjusted and optimized profile and contour of the automobile fender part b according to the second embodiment of the invention, and the arrangement positions of the springback collection points M1-M18 are shown in fig. 9. The values of the profile and profile after the second adjustment optimization for the simulated springback acquisition points are shown in table 7. Wherein positive values represent rebound outward of the vehicle body.

TABLE 7 Resilience values of profile and contour simulation Resilience acquisition points after second adjustment optimization

Point location	Value/mm	Point location	Value/mm
				M1	0.492	M10	-0.925
M2	0.325	M11	-0.753
				M3	-0.105	M12	-0.233
M4	-0.448	M13	-0.070
				M5	-1.154	M14	-0.037
M6	-1.164	M15	0.109
				M7	-1.125	M16	0.092
M8	0.133	M17	-0.001
				M9	-1.532	M18	0.047

And the constraint scheme after the second adjustment and optimization meets the conditions of the rebound constraint force and the rebound value, which is used as a basic FBC constraint mode for carrying out iterative calculation of full profile rebound compensation for the final constraint scheme.

The method comprises the following steps of arranging a plurality of acquisition points of resilience values on a fender part b, verifying and compensating resilience constraint force of constraint points after iteration, and adopting the following two constraint modes: a base FBC constraint mode and a true measurement constraint mode defined according to the part RPS scheme.

And for the automobile fender part b with larger rebound amount caused by rebound torsion before compensation, namely, needing to be subjected to secondary adjustment and optimization through the fifth step, the third preset requirement is that the rebound restraining force of each X-direction restraining point and each Y-direction restraining point is less than or equal to the second preset restraining force in the two restraining modes. In this embodiment, the third preset requirement is that the constraining forces of the X-direction constraining point and the Y-direction constraining point in the two constraining manners both satisfy ≤ 5N.

The fender part b in the embodiment is in this case, and therefore, it is necessary to satisfy that the restraining force of each of the X-direction restraining point and the Y-direction restraining point satisfies ≦ 5N in both the two restraining manners.

Fig. 10a discloses a schematic diagram of a basic FBC constraint mode after compensation iteration of a fender part b according to a second embodiment of the invention, wherein each constraint point comprises 1X-direction constraint point FBC _ X1, 2Z-direction constraint points FBC _ Z1 and FBC _ Z2, and 3Y-direction constraint points FBC _ Y1, FBC _ Y2 and FBC _ Y3, and the arrangement positions of the points are as shown in fig. 10 a. Under the constraint scheme shown in fig. 10a, the compensation iteratively calculated rebound restraining forces for each restraining point are shown in table 8, where positive values represent rebound outward of the body.

The X-direction force and the Y-direction force of each constraint point both meet the requirement that the number of the constraint points is less than or equal to 5N.

TABLE 8 Compensation of the Resilience restraint calculated under the basic FBC restraint mode after iteration (part b)

Fig. 10b discloses a schematic diagram of the actual clamping constraint manner of the automobile fender part b according to the RPS after compensation iteration, wherein each constraint point comprises a constraint point Clamp _1, a constraint point Clamp _2, a constraint point Clamp _3, a constraint point Clamp _4, a constraint point Clamp _5, a constraint point Clamp _6, a constraint point Clamp _7, a constraint point Clamp _8, a positioning pin1 and a positioning pin2, and the arrangement positions of the constraint points are shown in fig. 10 b. Under the restraint scheme shown in FIG. 10b, the compensation calculated rebound restraint force is shown in Table 9, where positive values represent rebound outward of the body.

The constraint force of each X-direction constraint point and each Y-direction constraint point meets the requirement that the constraint force is less than or equal to 5N.

TABLE 9 Compensation for calculated rebound restraint force after iteration under true measurement restraint scheme defined by part RPS scheme (part b)

After the verification, the final constraint scheme is judged to meet all the requirements, and the finally confirmed constraint scheme is shown in fig. 11, where each constraint point includes 1X-direction constraint point FBC _ X1, 2Z-direction constraint points FBC _ Z1 and FBC _ Z2, and 4Y-direction constraint points FBC _ Y1, FBC _ Y2, FBC _ Y3, and FBC _ Y4. Wherein Z-direction constraint points FBC _ Z1 and FBC _ Z2 are adjusted, and Y-direction constraint point FBC _ Y4 is a newly added constraint point.

While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance with one or more embodiments, occur in different orders and/or concurrently with other acts from that shown and described herein or not shown and described herein, as would be understood by one skilled in the art.

As used in this application and the appended claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that steps and elements are included which are explicitly identified, that the steps and elements do not form an exclusive list, and that a method or apparatus may include other steps or elements.

The embodiments described above are provided to enable persons skilled in the art to make or use the invention and that modifications or variations can be made to the embodiments described above by persons skilled in the art without departing from the inventive concept of the present invention, so that the scope of protection of the present invention is not limited by the embodiments described above but should be accorded the widest scope consistent with the innovative features set forth in the claims.

Claims

1. A restraint method for full profile springback compensation of an automobile fender is characterized by comprising the following steps:

2. A method of restraining full profile rebound compensation of an automobile fender according to claim 1, wherein:

before the first step, defining the placement direction of the fender according to the installation direction of the fender on the vehicle body, wherein the placement direction of the fender is consistent with the gravity condition in a loading state;

3. A method of restraining full face springback compensation of a fender according to claim 2, wherein in the first step: setting a preliminary constraint scheme based on a 3-2-1 principle, wherein the 3-2-1 principle is that 6 constraint points are selected at positioning points and loading matching points, and the 6 constraint points comprise 1X-direction constraint point, 2Z-direction constraint points and 3Y-direction constraint points.

4. A method for restraining full-face springback compensation of an automobile fender according to claim 2, wherein in the first step, the setting positions of 6 restraining points are as follows:

5. A method of restraining full profile rebound compensation of an automobile fender according to claim 4, wherein the set position of the restraining point is matched with the main characteristic line.

6. A method of restraining full profile rebound compensation of an automobile fender according to claim 2, wherein in the second step, the first predetermined requirement for the rebound restraining force further comprises:

7. The method for restraining the automobile fender full-profile rebound compensation according to claim 2, wherein in the third step, the first adjustment and optimization is performed, a moment arm of the restraining point is adjusted and controlled according to a moment balance principle under a gravity condition, and the rebound restraining force of the corresponding restraining point is adjusted and optimized.

8. A method for restraining full-profile springback compensation of an automobile fender according to claim 7, wherein in the third step, the first adjustment optimization is performed to control the springback restraining force of the Y-direction restraining point and/or the X-direction restraining point by controlling the arm of the Z-direction restraining point relative to the center of gravity and moving the position of the Z-direction restraining point.

9. A method for restraining full-face springback compensation of an automobile fender according to claim 2, wherein in the fourth step, the second preset requirement for the springback value further comprises:

the rebound value of the A surface of the automobile fender is smaller than or equal to a first preset rebound value.

10. A method for restraining full-face springback compensation of an automobile fender according to claim 2, wherein in the fifth step, the second adjustment and optimization comprises the following steps:

11. A method of constraining fender full face rebound compensation according to claim 10, wherein the second tuning optimization in step five includes the following steps:

12. A method for restraining full-profile rebound compensation of an automobile fender according to claim 2, wherein in the seventh step, the rebound restraining force of the restraint point after the iteration of compensation is verified, and the constraint mode is a basic fixed boundary condition constraint mode.

13. The method for restraining the automobile fender full-profile rebound compensation according to claim 1, wherein in the seventh step, the rebound restraining force of the restraint point after the compensation iteration is verified, and the adopted restraining mode is a real measurement restraining mode defined according to a part positioning point system scheme.

14. A method for restraining full-face springback compensation of an automobile fender according to claim 1, wherein in the seventh step, the third preset requirement further includes:

15. A method for restraining full-face springback compensation of an automobile fender according to claim 1, wherein in the seventh step, the third preset requirement further includes: