CN103994726B - Fit between a kind of sheet metal component and mould the detection method in gap - Google Patents

Abstract

The invention discloses the detection method in gap of fitting between a kind of sheet metal component and mould, comprise the following steps: 1) utilize three-dimensional optical scanning survey equipment respectively the coating surface of sheet metal component and mould to be measured, it is thus achieved that the three-dimensional measurement cloud data on each surface；2) utilize constrained model alignment schemes that sheet metal component measurement data is most preferably fitted with mould measurement data to align；3) calculate each distance measured between the closest approach that point is corresponding with mold data on sheet metal component, be i.e. at this and the laminating gap of mould on sheet metal component.The optimal laminating that the present invention realizes between sheet metal component with mould according to algorithm is alignd, it is not necessary to arranges auxiliary locator in advance on sheet metal component and mould, improves the accuracy of detection in laminating gap simultaneously.

Description

Fit between a kind of sheet metal component and mould the detection method in gap

Technical field

The present invention relates to sheet metal component detection technique field, the detection side in gap of fitting between a kind of sheet metal component and mould Method.

Background technology

Sheet metal component aircraft, automobile and other industries parts in occupy sizable ratio, such as aircraft skin, bulkhead, the wing Rib, automobile panel etc., have high size and dimension requirement.In order to ensure the quality of sheet metal component product, processing Needing after one-tenth to detect its profile, wherein the laminating gap between sheet metal component with corresponding mould is an important detection Content.Laminating gap is not only used for evaluating the surface accuracy of sheet metal component, more can affect into by analyzing to find out on it The key factor of shape technique, provides reference for sheet metal component Design Processing with improving.

At present, sheet metal component with the detection method in mould laminating gap is: tested sheet metal component is placed and secured in corresponding mould On tool, then feeler gauge is filled in the gap of sheet metal component and mould, obtain laminating gap from the size of feeler gauge.Owing to being filled in Entering the restriction of method, the laminating gap of sheet metal component edge can only be detected by this method, cannot fill in feeler gauge Middle part then cannot be detected.Additionally being limited by feeler gauge size in kind and precision, accuracy of detection is not high enough.

Above-mentioned detection method is commonly referred to analog quantity detecting method, utilizes three coordinate measuring machine, three-dimensional optical to scan in recent years More and more applied Deng digitizing detection method.

In digitizing detection method, utilize three-dimensional optical scanning survey equipment that testee surface is measured Substantial amounts of application.At present, three-dimensional optical scanning survey equipment is utilized sheet metal component surface can be carried out DATA REASONING, then Measurement data is carried out best alignment with the design digital-to-analogue of sheet metal component (or corresponding mould digital-to-analogue), it is thus achieved that tested part And the error between design digital-to-analogue, but this error can not represent the gap between sheet metal component and mould.Main cause is: (1) sheet metal component requires when fitting with mould mutually to penetrate, and common best alignment method is so that and is compared The range error on two surfaces is minimum, there is the situation that surface penetrates mutually；(2) a lot of situations between sheet metal component and mould Under by location hole/pin ensure sheet metal component will not lateral sliding, common best alignment method does not accounts for this factor.

Summary of the invention

The present invention is to solve and existing digitizing detection method can not represent the problem in gap between sheet metal component and mould, carry Supplied to fit between a kind of sheet metal component and mould the detection method in gap, realizes between sheet metal component and mould according to algorithm Good laminating alignment, it is not necessary to arrange auxiliary locator in advance on sheet metal component and mould, improve the inspection in laminating gap simultaneously Survey precision.

The invention provides the detection method in gap of fitting between a kind of sheet metal component and mould, comprise the following steps:

1) three-dimensional optical scanning survey equipment is utilized respectively the coating surface of sheet metal component and mould to be measured, it is thus achieved that The three-dimensional measurement cloud data on each surface；

2) utilize constrained model alignment schemes that sheet metal component measurement data is most preferably fitted with mould measurement data Alignment, the object function that sheet metal component measurement data is alignd with mould measurement data model is:

$\underset{R,T}{\min }\underset{i=1}{\overset{n+m}{\mathrm{\Σ}}}{w}_i{\left|\right|{\mathrm{RP}}_i+T-Q_i\left|\right|}^2$

Wherein, P_iFor the measurement data points on sheet metal component, Q_iFor in mold former with P_iCorresponding closest approach, n is surface The number of point, m is the number of location feature point, w_iFor weights, spin matrix that R, T are respectively in coordinate transform and Translation vector；

3) calculate each distance measured between the closest approach that point is corresponding with mold data on sheet metal component, be i.e. should on sheet metal component Place and the laminating gap of mould, the computing formula in laminating gap is h_i(R, T)=(RP_i+T-Q_i)·n_i。

Step 2) described in constrained model alignment schemes include location fit constraint and surface laminating constraint.

Described location fit is constrained to: τ_j≤b_j(R,T)≤μ_j(j=1,2 ..., m), wherein b_j(R, T) is on sheet metal component Location feature point is to the distance of theoretical model localizer, τ_j、μ_jIt is respectively minimum and maximum binding occurrence.

Described surface laminating is constrained to: h_i(R, T) >=0 (i=1,2 ..., n), wherein h_i(R, T) is P_iPoint is managed to mould The distance of closest approach on opinion model, this value is also P_iThe laminating gap of point.

The present invention has the beneficial effects that:

1, the optimal laminating realized between sheet metal component with mould according to algorithm is alignd, it is not necessary in advance on sheet metal component and mould Arrange auxiliary locator, improve the accuracy of detection in laminating gap simultaneously.

2, use three-dimensional optical scanning survey equipment, it is possible to the coating surface of sheet metal component and mould is carried out high-precision, The measurement of full details.

Accompanying drawing explanation

Fig. 1 is the sheet metal component schematic diagram of the embodiment of the present invention.

Fig. 2 is the mould schematic diagram of the embodiment of the present invention.

Fig. 3 is that sheet metal component and the mould laminating of the embodiment of the present invention is alignd schematic diagram.

Fig. 4 is gap schematic diagram of fitting between the sheet metal component of the embodiment of the present invention and mould.

Fig. 5 is the measurement data schematic diagram of the sheet metal component of the embodiment of the present invention.

Fig. 6 is the mould measurement data schematic diagram of the embodiment of the present invention.

When Fig. 7 is the location fit of the embodiment of the present invention, on sheet metal component, on the data in hole and mould, deviations between alignment pin shows It is intended to.

Fig. 8 is measurement data and the mould measurement data of the sheet metal component of the embodiment of the present invention knot under constrained model aligns Really.

Detailed description of the invention

The invention will be further described below in conjunction with the accompanying drawings.

The present embodiment is as shown in Fig. 1～8, and this enforcement provides a kind of sheet metal component and mould laminating gap detection method, with one As a example by the mould that rib part is corresponding, such as Fig. 1,2 signals, both laminatings such as Fig. 3 illustrates, laminating gap is such as Fig. 4 illustrates.

The enforcement step of the present embodiment is as follows.

Step 1, uses the three-dimensional optical scanning survey equipment coating surface (being the inner surface of part here) to sheet metal component Carrying out DATA REASONING respectively with the surface of mould, measurement result is as shown in Figure 5, Figure 6.

Two groups of measurement data are carried out constrained model alignment by step 2.

The object function that sheet metal component measurement data is alignd with mould measurement data model is:

$\underset{R,T}{\min }\underset{i=1}{\overset{n+m}{\mathrm{\Σ}}}{w}_i{\left|\right|{\mathrm{RP}}_i+T-Q_i\left|\right|}^2---\left(1\right)$

In formula (1):

P_iFor the measurement data points (including surface point cloud and location feature point) on sheet metal component, Q_iFor in mold former with P_iRight The closest approach answered, n is the number of surface point, and m is the number of location feature point, w_i(P is worked as weights_iWhen participating in location, w_iIt is 1, is otherwise 0)；

Spin matrix that R, T are respectively in coordinate transform and translation vector, be the variable optimized；

Described constrained model alignment includes location feature fiting constraint and surface laminating constraint.Location feature coordinates about Bundle is less than or equal to given public affairs for the deviations between locating data and the localizer in mould in sheet metal component Difference, i.e. τ_j≤b_j(R,T)≤μ_j(j=1,2 ..., m)；It is oriented that surface laminating is constrained between sheet metal component data and mold data Distance more than or equal to zero, i.e. h_i(R, T) >=0 (i=1,2 ..., n).

τ_j≤b_j(R,T)≤μ_jIt is location feature fiting constraint, b_j(R, T) is that the location feature point on sheet metal component is to theoretical mould The distance of type localizer, τ_j、μ_jIt is respectively minimum and maximum binding occurrence；

h_i(R, T) >=0 is surface laminating constraint, h_i(R, T) is P_iPoint, should to the distance of closest approach on mould theoretical model Value is also P_iThe laminating gap of point.

In the present embodiment, location feature coordinates coordinating for location hole and locating shaft, constraint schematic diagram such as Fig. 7.In Fig. 7 Axis a is the central axis of alignment pin, and A is a bit on axis a, and P is that center, hole, tested sheet metal component location (can lead to Cross and location hole contour line is justified matching obtain), hole, location requires be enclosed within pin, tolerance the most just, if giving Determining tolerance is [0, t], then this position error b is:

B=| | a × (P-A) | | (2)

Therefore, the location feature in formula (1) is retrained by the present embodiment has: b_j(R, T)=| | a_j×(RP_j+T-A_j) | |, τ_j=0, μ_j=t.

Surface laminating constraint is used for ensureing that part fits with mould tire but do not penetrates through, and i.e. part is in the outside of film tire.

Being calculated as of patch die clearance:

h_i(R, T)=(RP_i+T-Q_i)·n_i (3)

N in formula (3)_iFor Q on theoretical model curved surface_iThe outer method of the unit at place is vowed.

Formula (1) is the least square problem under a constraint, constrained optimization problems can be changed by Augmented Lagrange method Solve for unconstrained problem, result such as Fig. 8 signal of aliging after solving.

Step 3, sheet metal component calculates with the laminating gap of mould.After alignment, formula (3) calculate sheet metal component and measure each point The laminating gap at place.

The experimental result of the present embodiment is as follows.

Location feature fiting constraint is tested.Situation 1 is for being not added with location feature fiting constraint, and situation 2 is fixed for increasing Position feature fiting constraint, pastes die clearance analysis result contrast as shown in table 1 in the case of two kinds.Situation 1 feature holes, zero Error at part upper inside surface is the least, and the error at survey portion inner surface is more or less the same substantially.Thus illustrate, use The inventive method can improve the precision that sheet metal component patch die clearance is analyzed.

Table 1 error analysis Comparative result (unit: mm)

The concrete application approach of the present invention is a lot, and the above is only the preferred embodiment of the present invention, it is noted that for For those skilled in the art, under the premise without departing from the principles of the invention, it is also possible to make some improvement, These improvement also should be regarded as protection scope of the present invention.

Claims (1)

1. the detection method in a gap of fitting between sheet metal component and mould, it is characterised in that comprise the following steps:

1) three-dimensional optical scanning survey equipment is utilized respectively the coating surface of sheet metal component and mould to be measured, it is thus achieved that The three-dimensional measurement cloud data on each surface；

2) utilize constrained model alignment schemes that sheet metal component measurement data is most preferably fitted with mould measurement data Alignment, the object function that sheet metal component measurement data is alignd with mould measurement data model is:

$\underset{R,T}{\min }\underset{i=1}{\overset{n+m}{\Σ}}{w}_i{||{\mathrm{RP}}_i+T-Q_i||}^2$

Wherein, P_iFor the measurement data points on sheet metal component, Q_iFor in mold former with P_iCorresponding closest approach, n is surface The number of point, m is the number of location feature point, w_iFor weights, spin matrix that R, T are respectively in coordinate transform and Translation vector；Described constrained model alignment schemes includes location fit constraint and surface laminating constraint, and described determines Position fiting constraint is: τ_j≤b_j(R,T)≤μ_j(j=1,2 ..., m), wherein b_j(R, T) is that the location feature point on sheet metal component arrives The distance of theoretical model localizer, τ_j、μ_jIt is respectively minimum and maximum binding occurrence；Described surface laminating is constrained to: h_i(R, T) >=0 (i=1,2 ..., n), wherein h_i(R, T) is P_iPut to the distance of closest approach on mould theoretical model, this value Also it is P_iThe laminating gap of point；

3) calculate each distance measured between the closest approach that point is corresponding with mold data on sheet metal component, be i.e. should on sheet metal component Place and the laminating gap of mould, the computing formula in laminating gap is h_i(R, T)=(RP_i+T-Q_i)·n_i, n_iFor theoretical model Q on curved surface_iThe outer method of the unit at place is vowed.