1. A method of reverse mapping an electrode part of a cyclotron, comprising the steps of:

s1, fixing the electrode part, and adhering a plurality of target seats on the electrode part;

s2, performing point cloud scanning measurement on the appearance of the electrode part by adopting a laser tracker and an optical three-dimensional scanner, and scanning the overall profile of the electrode part;

and S3, importing the point cloud data of the whole outline of the electrode part obtained by scanning into reverse engineering software for processing, and drawing a solid model of the electrode part.

2. The method for reverse mapping an electrode part of a cyclotron of claim 1, wherein the step S1 includes:

fixing the scanned electrode part on the ground;

and sticking a plurality of target seats on the surface of the electrode part with good visibility by adopting 502 glue, wherein the plurality of target seats are used as public transfer stations of the electrode part.

3. The method for reverse mapping an electrode part of a cyclotron of claim 1, wherein the step S2 includes:

s21, erecting a laser tracker at a distance of about 2 meters outside the electrode part, wherein the laser tracker is connected with an optical three-dimensional scanner and a workstation computer;

s22, scanning and measuring the first position and posture of the electrode part;

s23, when all the outlines of the first position and the posture of the electrode part are scanned, measuring a common target point by using an SMR (surface-reflection-type laser) reflection ball to obtain transfer station data;

s24, moving the electrode part to turn over, moving the electrode part to a second position, fixing the posture, and ensuring that the target point can be seen through by laser emitted by the instrument after turning over;

s25, resetting the laser tracker, measuring a common target point through an SMR (SMR-SMR) reflection sphere, restoring the instrument to a coordinate system in a first position measurement state through a point group best fitting function, and scanning electrode part outline point cloud data in a second position;

and S26, storing point cloud data after the electrode part is integrally scanned.

4. The method for reverse mapping cyclotron electrode parts of claim 3, wherein the process of step S3 includes:

s31, preprocessing the point cloud;

s32, performing surface tiling on the point cloud data to construct a triangular surface patch;

s33, performing field segmentation on the constructed triangular patch, constructing a reference element according to the field of the patch, performing orthogonalization alignment on the triangular patch, and drawing each characteristic contour by intercepting the contour line of the patch to complete modeling;

and S34, carrying out precision analysis on the electrode part model after modeling, and outputting the model to a solid model in a set format if the model precision meets the set requirement.

5. The method for reverse mapping cyclotron electrode parts of claim 4, wherein the process of step S31 includes: and storing the point cloud data of the electrode parts into a TXT file, importing the TXT file into Geomagic Design reverse Design software, carrying out miscellaneous point elimination, sampling and smoothing on scanning data, completely eliminating miscellaneous points collected by white light diffuse reflection, and refining the number of points into a set proportion according to a ratio.

6. The method for reverse mapping cyclotron electrode parts of claim 4, wherein the process of step S32 includes: and constructing the point cloud of the electrode part into a triangular patch, repairing the whole triangular patch, filling holes, smoothing sharp parts, and determining the inner side or outer side area of the electrode part according to the normal direction of the patch body.

7. The method for reverse mapping cyclotron electrode parts of claim 4, wherein the process of step S34 includes: and comparing the drawn electrode part model with the point cloud data through a color difference graph of software, and modifying the place with the error exceeding the set error.

8. A method of reverse mapping cyclotron electrode parts of any one of claims 1 to 7, wherein the laser tracker uses a Leica AT960 laser tracker.

9. A method for reverse mapping of cyclotron electrode parts according to any one of claims 1 to 7, wherein the optical three dimensional scanner uses a LAS-XL scanning stylus.

Background

In the field of accelerators, SSC split cyclotrons are experimental devices that operate for more than 30 years, in which the electric field generated by the electrodes between the cyclotron blades has the effect of deflecting the high-energy particle beam, requiring extremely high machining accuracy.

Since the design years are long, no CAD software (computer aided design software) is used for manual drawing in 70 years, some drawings are lost, the old parts need to be copied and drawn at present, but the curved surfaces and arcs on the surfaces of the electrode products are too many, the overall shapes of the parts are difficult to obtain by directly using common measuring tools, and in the parts after the accelerator is operated, the surfaces of objects have radioactivity, so that the dose of radioactive radiation which cannot be seen by human eyes can be remained, and the parts can be damaged by long-time contact of personnel, so that the non-contact measuring scheme is most suitable, and on the basis, the reverse engineering technology is considered to be used for restoring the outline of the whole electrode shell part.

In the reverse engineering scanning instrument mainly used in the world at present, the fitting precision of data measured by a fixed standard ball transfer station method at two stations is more than 0.05 mm, and when no public transfer station exists, the data measured twice are generally integrated by using a point cloud fitting and splicing method, but the error of the method processed by pure software is very large and is generally more than 0.10 mm.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a method for reverse mapping an electrode part of a cyclotron, in which a common target transfer station is fixed on the electrode part to combine two measurement modes, namely contact-type high-precision single-point measurement and non-contact point cloud scanning, so as to effectively improve the precision of fitting data.

In order to achieve the purpose, the invention adopts the following technical scheme: a method of reverse mapping a cyclotron electrode part comprising the steps of:

s1, fixing the electrode part, and adhering a plurality of target seats on the electrode part;

s2, performing point cloud scanning measurement on the appearance of the electrode part by adopting a laser tracker and an optical three-dimensional scanner, and scanning the overall profile of the electrode part;

and S3, importing the point cloud data of the whole electrode part contour obtained by scanning into reverse engineering software for processing, and drawing a solid electrode part contour model.

Further, the process of the above step S1 includes:

fixing the scanned electrode part on the ground;

and adhering a plurality of target seats with 502 glue on the surface of the electrode part with good visibility, wherein the plurality of target seats are used as public transfer stations of the electrode part.

Further, the process of the above step S2 includes:

s21, erecting a laser tracker at a distance of about 2 meters outside the electrode part, wherein the laser tracker is connected with an optical three-dimensional scanner and a workstation computer;

s22, scanning and measuring the first position and posture of the electrode part;

s23, when all the outlines of the first position and the posture of the electrode part are scanned, measuring a common target point by using an SMR (surface-reflection-type laser) reflection ball to obtain transfer station data;

s24, moving the electrode part to turn over, moving the electrode part to a second position, fixing the posture, and ensuring that the target point can be seen through by laser emitted by the instrument after turning over;

s25, resetting the laser tracker, measuring a common target point through an SMR (SMR-SMR) reflection sphere, restoring the instrument to a coordinate system in a first position measurement state through a point group best fitting function, and scanning electrode part outline point cloud data in a second position;

and S26, storing point cloud data after the electrode part is integrally scanned.

Further, the process of step S3 includes:

s31, preprocessing the point cloud;

s32, performing surface tiling on the point cloud data to construct a triangular surface patch;

s33, performing field segmentation on the constructed triangular patch, constructing a reference element according to the field of the patch, performing orthogonalization alignment on the triangular patch, drawing each characteristic contour by intercepting the contour line of the patch, and performing entity drawing to complete modeling;

and S34, carrying out precision analysis on the electrode part model after modeling, and outputting the model to a solid model in a set format if the model precision meets the set requirement.

Further, the process of step S31 includes: and storing the point cloud data of the electrode parts into a TXT file, importing the TXT file into Geomagic Design reverse Design software, firstly, carrying out miscellaneous point elimination and sampling and smoothing on scanning data, completely eliminating miscellaneous points collected by white light diffuse reflection, and thinning the number of points into a set proportion according to a ratio.

Further, the process of step S32 includes: and constructing the point cloud of the electrode part into a triangular patch, repairing the whole triangular patch, filling holes, smoothing sharp parts, and determining the inner side or outer side area of the electrode part according to the normal direction of the patch body.

Further, the process of step S34 includes: and comparing the drawn electrode part model with the point cloud data through a color difference graph of software, and modifying the place with the error exceeding the set error.

Further, the laser tracker adopts a Leica AT960 laser tracker.

Further, the optical three-dimensional scanner adopts an LAS-XL scanning measuring head.

Due to the adoption of the technical scheme, the invention has the following advantages:

1. the invention perfectly combines two measuring modes of contact type high-precision single-point measurement and non-contact type point cloud scanning together by fixing a common target transfer station on an electrode part and controlling a transfer station by reflection ball measurement, so that under the state of twice station setting, the data of twice point cloud scanning can be integrated into a coordinate system with very small error (less than or equal to 0.05 mm), and the invention is the application of the latest technology in the field of current measuring instruments;

2. the invention applies a plurality of three-dimensional digitization technologies to engineering practice in a unified way, including an optical digitization point cloud scanning technology, a three-dimensional space single-point technology measured by a laser reflection principle, a point cloud digitization processing technology, a three-dimensional CAD solid modeling technology and the like which are orderly integrated and applied;

in conclusion, the invention can be widely applied to the measurement of the electrode parts of the cyclotron.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Like reference numerals refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a working scenario of an embodiment of the present invention, using a Leica AT960 laser tracker in conjunction with a LAS-XL scanning probe to scan two poses of an electrode part;

fig. 2 is a schematic diagram illustrating an effect of processing scan data in reverse engineering according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be used.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

For convenience of description, spatially relative terms, such as "inner", "outer", "lower", "upper", and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.

The method for reversely mapping the electrode parts of the cyclotron provided by the embodiment of the invention is characterized in that the laser tracker is matched with a three-dimensional optical point cloud scanning system, and the method comprises the following steps of: the reverse mapping of the electrode shell and/or the electrode head comprises the following steps:

s1, for example, the electrode shell 1 is fixed, a plurality of target seats are pasted on the electrode shell 1, and the electrode shell 1 is fixedly pasted with the metal target seats, so that the common target point can be measured by the laser tracker under two position postures of the electrode shell by using the reflection ball.

Specifically, as shown in fig. 1, the electrode housing 1 to be scanned is fixed on the ground, and on a surface of the electrode housing 1 with good visibility, 502 glue is used to adhere four target holders (for example, without limitation, the number of the target holders is selected according to actual needs), positions of the four target holders are required to be dispersed as much as possible, the closer to the edge of the plane of the electrode housing 1 is, the better the four target holders are, the farther the relative distance is, the more accurate the calculated six degrees of freedom are, and specific positions are selected according to actual needs, without limitation.

And S2, performing point cloud scanning measurement on the appearance of the visible part of the electrode shell 1 by adopting the laser tracker 2 and the optical three-dimensional scanner 3, and scanning the whole outline of the electrode shell 1. And measuring the four adhered target points by using SMR (surface-reflection-type laser) reflecting balls to obtain target points of a turning station of the laser tracker 2, moving the electrode shell 1 to turn over and fix, measuring the four target points, recovering a control network coordinate system for the first measurement, and scanning the other part of the visible appearance of the electrode shell 1 again.

Specifically, a Leica AT960 laser tracker 2 can be erected outside the electrode shell 1 by about 2 meters, and the laser tracker 2 is connected with a LAS-XL optical three-dimensional scanning measuring head 3 and a workstation computer. After the instrument is preheated, the electrode shell 1 starts to be scanned. When scanning, the overall contour of the electrode housing 1 and parts of major details, such as flanges, pipes, slots, are scanned as far as possible, as many point clouds are scanned as possible, large planes and curved surfaces are to be scanned at least 80% of the surface.

And when all the contours are scanned, the common target point is measured by using SMR (SMR) reflecting balls by wearing gloves, and station transfer data is obtained. The movable electrode shell 1 is turned over, the electrode shell is moved to the second position and fixed in posture, the laser tracker 2 is added with instruments again to establish a station, and the four target points can be seen through after being turned over. And (2) resetting the laser tracker 2, firstly measuring four common target points through SMR (SMR) reflecting balls, restoring the instrument to a coordinate system in a first measuring state through a point group best fitting function, and scanning outline point cloud data of a second station, so that the point cloud scanned by the second station and the point cloud scanned by the first station are defaulted to be in the coordinate system, the scanning data of the two stations can be perfectly attached, and the fitting error of the switching station is controlled within 0.05 mm. And scanning the remaining outline of the electrode shell 1 in the second station state, and storing data after the integral scanning is finished.

S3, as shown in fig. 2, importing the electrode point cloud data obtained by the two scanning into reverse engineering software for processing, and synthesizing all the drawn outlines into an entity through boolean operation, where the entity can be exported to other mainstream three-dimensional CAD software for direct use or for numerical control processing, and the specific process is as follows:

s31, preprocessing the point cloud, including: denoising, refining, operating according to ratio sparse measurement points and the like, deleting impurity removal points and the like

Specifically, the method comprises the following steps: the TXT file is imported into Geomagic Design reverse Design software, firstly, the scanned data is processed by miscellaneous point elimination, sampling and smoothing, all miscellaneous points collected by white light diffuse reflection are removed, and the point cloud data amount is huge, millions of points are refined to be within 10% according to the ratio, so that the burden of computer analysis and calculation can be reduced.

And S32, forming the point cloud patch into a triangular patch, orthogonalizing and aligning the triangular patch, and drawing each characteristic contour of the scanned piece by intercepting the contour line of the patch.

Specifically, the point cloud of the electrode shell is constructed into a triangular patch, the integral triangular patch is repaired, holes are filled, the sharp part is subjected to smoothing treatment, the patch body looks smooth and three-dimensional, the normal direction of the patch is turned, the normal direction of the patch body is noticed, the inner side or the outer side of the electrode shell 1 is determined, and if the direction is wrong, the electrode shell needs to be manually turned over. And after the dough sheet is processed, the cross section shape of the part is constructed through the dough sheet body for modeling.

S33, segmentation field, reference alignment and model drawing: and performing field segmentation on the established dough sheet, constructing a reference element according to the field of the dough sheet, aligning and aligning the whole dough sheet body before modeling, and aligning and parallel the placing position direction of the part and the coordinate system direction of the design software.

Specifically, several surfaces of the electrode casing 1 are observed, and except for one large arc surface which is a curved surface, other planes are all planes with small curvature, and can be used as the reference of the constructed part. The area division operation is carried out on the dough sheet body, the operation can divide the whole dough sheet body into a plurality of independent areas according to the curvature of the dough sheet body, and the large plane can be seen to be basically divided into a relatively large dough sheet body area and a plurality of small dough sheet body areas to be combined. And (3) constructing a theoretical plane, and performing least square best fitting through the data of the panel bodies to construct two small side faces, a top face and a back face. And a symmetrical plane is constructed on the two small side surfaces, the symmetrical plane and the back surface are intersected to obtain an intersection line, and the intersection line and the top surface are intersected to obtain an origin. And through a manual alignment command of software, the intersection point of the three surfaces is designated as the origin of a coordinate system, the normal direction of the top surface is the direction of the coordinate system plus Y, and the bisector surface is the direction of the coordinate system plus X. Moving and aligning the center of a design coordinate system, drawing a patch sketch on three reference surfaces, wherein the patch sketch can project section lines with specified depth in the sketch direction on a sketch surface, a designer can directly draw the outline of a part through the section lines, the situation that the projected section lines are interrupted or distorted due to incomplete point cloud scanning data can be met, and the size can be trimmed according to actual needs, for example: the sketching line is possibly not orthogonal to the coordinate system, and can be manually restrained to be horizontal or vertical; the sketched dimensions are not integers, e.g. a circle with a diameter of 35.09 can be drawn as 35, since the original model is designed with certain considerations for dimensions close to integers and the reverse engineering redesign takes into account the original designer's intentions at the time. For regularity of subsequent repeated processing. And drawing the whole part entity by stretching, rotating, scanning and other functions, finally combining all drawn features into a whole by Boolean operation, and finishing the modeling work.

And S34, analyzing model precision, and if the model precision meets the set requirement, outputting the entity model of the model in the set format.

Specifically, the deviation between the drawn electrode model and the point cloud data is compared through a color difference graph of software, and places with large errors are modified, so that the errors are reduced.

And converting the drawn electrode model into a standard format such as Step. The accuracy of the model after the reverse is not necessarily completely consistent with the scanned data, self-checking is needed, an accuracy analysis interface of software is opened, a body deviation option is clicked, the software can be seen to display a color difference graph to reflect the deviation between the modeled entity and the initial patch body, the deeper the red represents the larger the deviation outside the material, the deeper the blue represents the larger the deviation inside the material, the green represents the acceptable deviation range, 0.3 mm can be selected, the scanning error of the instrument is approximately in the range, if the surface of the part displays that the green represents the drawn model and the original data are consistent, if the color is deviated to the blue or the red, the drawing problem is required to be rechecked and modified. It should be noted that some places are areas where the point cloud data is not scanned, which may show that the data is seriously out of tolerance and should be treated differently. After the model precision verification is free of problems, the output of the model can be converted into a format which can be directly identified by step, iges or other mainstream three-dimensional mechanical design software such as Solidworks, Catia and the like.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: it is to be understood that modifications may be made to the above-described arrangements in the embodiments or equivalents may be substituted for some of the features of the embodiments without departing from the spirit or scope of the present invention.