Summary of the invention
Aiming at the problems existing in the prior art, the present invention provides a kind of labyrinth blank processing based on three-dimensional reverse
Localization method, rationally, method is simple, can efficiently confirm that can blank in global female member, and guarantee part for design
Each face allowance balance it is uniform.
The present invention is to be achieved through the following technical solutions:
A kind of labyrinth blank processing positioning method based on three-dimensional reverse, includes the following steps,
Step 1, before blank does not carry out upper machine clamping, positioning datum is marked on blank;
Step 2, the measurement for carrying out threedimensional model to the blank of labeled positioning datum by three-dimension measuring system, obtains three
The blank measurement model of dimension;
Step 3, allowance distribution optimizes, and obtains blank point cloud according to collected blank measurement model, by being based on region
The point cloud segmentation algorithm of growth is split blank point cloud, obtains point cloud dough sheet corresponding to each face on blank;
The corresponding relationship of each dough sheet of blank point cloud segmentation and the curved surface that designs a model of workpiece is set, and workpiece is set
Each curved surface that designs a model machining allowance;
The pose adjustment of blank point cloud is solved by ICP algorithm and genetic algorithm according to corresponding relationship and machining allowance
Amount matches to carry out pose transformation to blank point cloud;
By adjusting the pose of blank measurement model, the measurement model of blank is enabled to contain designing a model for workpiece,
And each machined surface can satisfy surplus requirement, then finds out the positioning datum that the label on blank measurement model is determined and sits
Mark system V ' arrives the transformation relation of programming coordinates system U ';
Step 4, the local coordinate that the label under lathe coordinate system on blank is determined will on blank clamping to lathe, be obtained
It is V, the transformation relation obtained according to step 3, the local coordinate system V determined to the label on blank under lathe coordinate system is carried out
Transformation, obtains Cutter coordinate system U, and the coordinate system parameters of Cutter coordinate system U are inputted lathe, carry out processing positioning to blank.
Preferably, in step 1, label is drawn with scriber or crayon on blank.
Preferably, it in step 1, is made marks on blank including not conllinear three point marked on blank or one
Two hole of face.
Preferably, in step 2, the method for three-dimensional measurement measured using laser scanning or 3-D photography obtains three-dimensional
Blank measurement model.
Preferably, in step 3, the positioning datum that the transformation relation is determined by the label on blank measurement model is sat
Mark system V ' arrives the amount of bias of programming coordinates system U ';In step 4, the part determined to the label on blank under lathe coordinate system is sat
Mark system V is biased according to amount of bias obtained in step 3, obtains Cutter coordinate system U.
Further, in step 3, the amount of bias (R, T) as follows,
R=U ' * (V ')-1
T=Om-A’
Wherein, the positioning datum coordinate system that V ' is determined by the label on blank measurement model;U ' is programming coordinates system, Om
For the origin of programming coordinates system U ', A ' is the origin of coordinate system V '.
Further, in step 4, each parameter difference of obtained Cutter coordinate system U is as follows,
The coordinate origin of Cutter coordinate system U is:
A+V*V'(-1)*T;
Wherein, the local coordinate system that V is determined by the label on blank under lathe coordinate system, on V ' blank measurement model
Determined positioning datum coordinate system is marked, A is the origin of coordinate system V;
The rotation angle [alpha] of tri- axis of Cutter coordinate system U, β and γ are acquired by following formula,
Wherein, α, β and γ are respectively coordinate system V with respect to lathe coordinate system X, Y, the rotation angle of Z axis;V ' blank measures mould
The positioning datum coordinate system that label in type is determined, U ' are programming coordinates systems, and V is the mark point under lathe coordinate system on blank
The local coordinate system determined.
Compared with prior art, the invention has the following beneficial technical effects:
The present invention is first made a mark on blank by crayon or scriber, and cooperation uses laser scanning, photogrammetric etc.
Three-dimensional measurement technology can obtain the true model of blank, can provide the true model of blank for programming personnel in this way, then pass through hair
Label on base can connect design coordinate system with lathe coordinate system;Pass through designing a model for Model Measured and part
It is matched, is optimized by allowance distribution, can be allocated for the surplus in each face of part by process requirements, and can pick
Except underproof blank;If carrying out allowance distribution by surplus optimization system, blank point cloud is still unable to female member, then hair
Base is unqualified, does not need to be adjusted workpiece pose or shorten adjustment time, improves processing efficiency, reduce worker's
Labor intensity, blank occupies the time of lathe when eliminating centering positioning, realizes post process gauging, improves machine tool utilization rate.
Specific embodiment
Below with reference to specific embodiment, the present invention is described in further detail, it is described be explanation of the invention and
It is not to limit.
A kind of labyrinth blank processing positioning method based on three-dimensional reverse of the present invention is mainly used for workpiece in processing
Fast aligning positioning, completed by three-dimension measuring system by computer.Before blank does not carry out upper machine clamping, on blank
It makes a mark, then carries out the measurement of threedimensional model to blank by three-dimension measuring system, then by the blank of collected three-dimensional
Measurement model is matched with designing a model for workpiece, by adjusting the pose of blank measurement model, so that the measurement mould of blank
Type can contain designing a model for workpiece, and each machined surface can satisfy surplus requirement, then find out blank measurement model
On the transformation relation for being tagged to programming coordinates system, then by blank clamping to lathe, using on lathe gauge head measurement blank
Mark point coordinate value under lathe coordinate system carries out the label on true blank then according to the transformation relation solved above
Transformation, can obtain accurate Cutter coordinate system parameter.It can quickly and accurately realize blank in processing using this method
Positioning and workpiece process in deformation the case where causing positioning datum to shift, save the mistake of artificial crossed centering
Journey, and can the surplus as desired to each machined surface of workpiece be allocated, engineering application value with higher.
A kind of labyrinth blank processing positioning method based on three-dimensional reverse of the present invention, includes the following steps:
The first step:Label is drawn with scriber or crayon on blank, the positioning datum as blank is marked using this, because
This, the label made is wanted to determine a coordinate system, makes marks on blank and generally marks phase on blank using coating
Away from farther away three points or Position with One Plane and Two Holes.
Second step:Using laser scanning or the method for photogrammetric equal three-dimensional measurements, blank is measured, thus
To three-dimensional blank measurement model.
Third step:Allowance distribution optimization, obtains blank point cloud according to collected blank measurement model, by being based on region
The point cloud segmentation algorithm of growth is split blank point cloud, obtains point cloud dough sheet corresponding to each face on blank;
The corresponding relationship of each dough sheet of blank point cloud segmentation and the curved surface that designs a model of workpiece is set, and workpiece is set
Each curved surface that designs a model machining allowance;
The pose adjustment of blank point cloud is solved by ICP algorithm and genetic algorithm according to corresponding relationship and machining allowance
Amount matches to carry out pose transformation to blank point cloud;
By adjusting the pose of blank measurement model, the measurement model of blank is enabled to contain designing a model for workpiece,
And each machined surface can satisfy surplus requirement, carry out reasonable distribution to the surplus in each face of part, and guarantee blank energy
Female member is found out in the case where designing coordinate system, and the determined positioning datum V ' of the label on blank measurement model arrives programming coordinates system
The amount of bias (R, T) of U '.
4th step:Clamping blank, measurement markers go out the positioning datum V being marked on true blank, position base to this
The amount of bias (R, T) that quasi- V is found out according to third step is biased, and obtains Cutter coordinate system U, coordinate system parameters are then inputted machine
Bed realizes quickly positioning.
It in actual use, can be according to following operation.
1, label used for positioning is marked with scriber or crayon on blank, what this label i.e. workpiece were used to position
Positioning datum can determine a coordinate system, such as three points, Position with One Plane and Two Holes etc. by this label.
2, using photogrammetric method, the threedimensional model of workpiece is measured.
3, blank measurement model is matched with Element Design model by allowance distribution system, by adjusting blank survey
The pose of model is measured, so that blank measurement model contains workpiece, and the surplus of each machined surface of reasonable distribution, then obtains hair
The amount of bias of positioning datum on base measurement model to programming benchmark.
4, by clamping workpiece to lathe table top, the parameter of the label on true blank is then measured as on true blank
Then positioning datum V is biased positioning datum according to the amount of bias that third step solves, can obtain accurately adding
This parameter is inputted lathe, so that it may start machined by work coordinate system parameters.
In order to realize the positioning of blank, the operation for needing to follow the steps below:
1, positioning datum is marked with scriber or paintbrush on workpiece, the label of positioning datum can be three points or two
Hole one side, A as shown in Figure 3, B, tri- points of C are the mark point of positioning datum, when marking positioning datum, in order to guarantee essence
Degree, place that as far as possible will be apart from each other on blank mark.
2, blank threedimensional model is acquired using three-dimensional measuring apparatus (laser scanning device or 3-D photography measuring device).
3, the three-dimensional measurement model of blank and designing a model for workpiece are imported into allowance distribution system, optimizes in surplus and distributes
System makes blank measure female member, and make the surplus in each face of part by adjusting the pose of blank measurement model
It meets the requirements, as shown in Figure 1, measuring the schematic diagram of the point cloud female member of blank, and workpiece after surplus optimization distribution
Each face surplus met process requirements as a result, its obtain as follows according to collected blank measure mould
Type obtains blank point cloud, by the point cloud segmentation algorithm based on region growing, is split to blank point cloud, obtains every on blank
Point cloud dough sheet corresponding to a face;Then each dough sheet that blank point cloud segmentation is arranged is corresponding with the curved surface that designs a model of workpiece
Relationship, and machining allowance is set to each curved surface that designs a model of workpiece, it is calculated according to corresponding relationship and machining allowance by ICP
Method and genetic algorithm solve the pose adjustment amount of blank point cloud, and carry out pose transformation to blank point cloud.As shown in Fig. 2, right
When workpiece carries out machining prgraming, A ', B ', C in figure ' be on blank measurement model with the A that is marked on blank, B, C tri-
The corresponding point of point, the positioning datum coordinate system V ' that X ' Y ' Z ' is determined by three points marked on blank measurement model, XmYmZm
For programming coordinates system U '.
Acquire the amount of bias (R, T) that coordinate system V ' at this time arrives programming coordinates system U '.
R=U ' * (V ')-1
T=Om-A’
Wherein, wherein the positioning datum coordinate system that V ' is determined by the label on blank measurement model, i.e. blank measure mould
When type contains part model and makes each face allowance distribution of part model uniform, the label above blank measurement model is being set
The local coordinate system that meter coordinate system is made decision;U ' is the programming coordinates system designed under coordinate system;OmFor the original of programming coordinates system U '
Point, the origin for the coordinate system that A ' is determined by the label on blank, the i.e. origin of coordinate system V '.
4, then workpiece is clamped on lathe, under lathe coordinate system, uses the label on lathe gauge head measurement blank
Point coordinate value under lathe coordinate system, obtains coordinate system V.Then coordinate V is converted by (R, T) that front is found out, is obtained
Coordinate origin to the parameter of Cutter coordinate system U, Cutter coordinate system is:
A+V*V'(-1)*T
Wherein, the origin for the coordinate system that A is determined by blank mark point, the i.e. origin of coordinate system V;V is lathe coordinate system
The local coordinate that the local coordinate system that label on lower blank is determined, i.e. mark point under lathe coordinate system on blank are determined
It is the positioning datum coordinate system that the label on V ' blank measurement model is determined.
The rotation angle of tri- axis of Cutter coordinate system U is:α, beta, gamma are acquired by following formula.
Wherein, α, β and γ are respectively coordinate system V with respect to lathe coordinate system X, Y, the rotation angle of Z axis;V ' blank measures mould
The positioning datum coordinate system that label in type is determined, U ' are programming coordinates systems, and V is the mark point under lathe coordinate system on blank
The local coordinate system determined.
As Fig. 3 be it is shown, workpiece is mounted on lathe, be mounted on lathe workpiece need through clamping, setting workpiece sit
Mark system can continue to process.In figure, A, B, tri- points of C are to be marked before measuring blank using paintbrush, XYZ coordinate system
It is positioning datum the coordinate system V, X determined on true blank by three points markedPYPZPFor Cutter coordinate system U.