Water turbine rotor three-dimensional measurement method based on precision transfer chain

Abstract

The invention discloses a water turbine rotor three-dimensional measurement method based on a precision transfer chain, and the method comprises the steps: firstly building a multi-level measurement control network composed of a tracker measurement target ball, a photogrammetry target ball and a local scanning target point, and forming a complete precision transfer system; and secondly, a bidirectional real-time verification measurement mechanism is adopted, and the reliability of the measurement process is ensured through combination of forward precision transmission and reverse precision verification and precision transmission verification of adjacent areas. And finally, aiming at the precision abnormity occurring in the measurement process, constructing a grading repair strategy based on the precision transfer chain, including abnormity judgment, grading repair and integrity verification. According to the method, a complete precision guarantee system is established while high-precision measurement of the geometrical characteristics of the large-size water turbine rotor is guaranteed, the problems that precision transmission is uncontrollable, a verification mechanism is incomplete and the like in a traditional measurement method are solved, and the measurement efficiency and reliability of the water turbine rotor can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of water turbine detection, and in particular to a three-dimensional measurement method of a water turbine rotor based on a precision transmission chain. Background Art

[0002] The turbine rotor is one of the key components of a hydropower unit, and its geometric dimensional accuracy directly affects the unit's operating efficiency and service life. As hydropower units develop towards larger sizes and higher efficiency, the requirements for rotor machining and measurement accuracy are becoming increasingly higher. At present, the measurement of turbine rotors mainly faces the following technical challenges: First, the turbine rotor is large in size and has large curvature changes, so it is difficult to achieve full coverage with a traditional single measurement method. For example, although the laser tracker has high measurement accuracy, it is limited by the field of view and cannot complete the measurement of all areas of the rotor; the laser scanner can obtain dense surface data, but the measurement accuracy in independent mode is difficult to guarantee.

[0003] Secondly, the existing rotor geometry measurement method lacks a complete precision transfer mechanism. In the actual measurement process, multiple measurement methods are often required to work together, but the precision transfer between the measurement systems lacks an effective control and verification mechanism, which makes it difficult to ensure the reliability of the final measurement results. Especially in the partition measurement of large-size rotors, the problem of splicing accuracy of adjacent areas is particularly prominent.

[0004] In addition, accuracy anomalies during the measurement process are difficult to detect and repair in a timely manner. Due to the lack of a systematic accuracy monitoring and verification mechanism, accuracy problems that occur during the measurement process are often not discovered until the later data processing, which not only increases the rework cost but also affects the measurement efficiency. Even if the problem is found, the existing technology lacks a targeted repair solution, and all measurements often need to be repeated.

[0005] In order to solve the above problems, it is urgent to develop a turbine rotor profile measurement method that can ensure reliable transmission of measurement accuracy, has a complete verification mechanism, and can promptly detect and repair accuracy problems. Summary of the invention

[0006] In order to solve the current technical problems, the main purpose of the present invention is to provide a three-dimensional measurement method for turbine rotors based on a precision transfer chain. By constructing a multi-level measurement control network, reliable precision transmission from high-precision benchmark to terminal measurement is achieved, solving the problem of accuracy assurance in geometric dimension measurement of large turbine rotors.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a three-dimensional measurement method of a turbine rotor based on a precision transmission chain, comprising the following steps: S1. Arrange different types of measurement benchmarks on the surface of the turbine rotor and establish a multi-level measurement control network; wherein the different types of measurement benchmarks include: arranging a tracker measurement target sphere, a photogrammetry target sphere and a scanning target point on the surface of the turbine rotor, and the multi-level measurement control network includes a high-precision benchmark network, a secondary control network and a local measurement network; S2. During measurement, a two-way real-time verification measurement mechanism is used to ensure the reliability of the measurement data by combining forward accuracy transfer and reverse accuracy verification, as well as accuracy transfer verification in adjacent areas; S3. Take repair measures based on the abnormal conditions at each level of the precision transfer chain and ensure the repair effect through verification.

[0008] In S1, the method of establishing a high-precision benchmark network includes: A magnetic base is used to fix the tracker measurement target sphere on the outer circumference of the turbine rotor. Each measurement area can observe more than three tracker measurement target spheres at the same time. The tracker measurement target sphere is measured by a laser tracker to obtain accurate spatial coordinates and establish a high-precision benchmark network.

[0009] In S1, the method of establishing a secondary control network includes: A magnetic base is used to fix the photogrammetry target sphere on the outer circumference of the turbine rotor. The overlap between the photogrammetry target spheres is maintained at 30%-50%. Images are collected through a global photogrammetry system, and combined with a high-precision reference network, the spatial position of the photogrammetry target sphere is calculated to form a reliable measurement control network.

[0010] In S1, the method of establishing a local measurement network includes: The entire turbine rotor is divided into several local measurement areas. At least three scanning target points are arranged in each local measurement area. The scanning target points form an effective observation overlap with the surrounding photogrammetry target spheres. A handheld laser scanner is used to identify the scanning target points to achieve scanning positioning, which is used to collect dense surface data of the local area of ​​the rotor outer circumference.

[0011] In S2, the forward precision transfer process is from high precision to low precision; Among them, the laser tracker first measures the target sphere to obtain the highest precision benchmark, and then uses these known high-precision coordinates to calibrate the global photogrammetry system, and then solves the spatial position of the photogrammetry target sphere. Finally, the handheld scanner obtains the spatial position of the surface data by identifying the scanning target points on the photogrammetry target sphere and the rotor surface.

[0012] In S2, reverse precision verification is to trace back from low precision to high precision; Among them, the scanning accuracy is verified by comparing the deviation of the scanning target point coordinates obtained by the handheld scanner with the photogrammetry target sphere coordinates given by photogrammetry, and then the photogrammetry accuracy is verified by comparing the photogrammetry target sphere coordinates with the tracker measurement target sphere coordinate deviation given by the laser tracker.

[0013] In S2, the accuracy transfer verification method of adjacent areas includes: The overlapping part of the two areas must include the complete precision transfer chain nodes, that is, there must be tracker measurement target sphere, photogrammetry target sphere and scanning target point. By comparing the coordinate consistency of these nodes in the two areas, it is ensured that the accuracy will not be attenuated during the area expansion process.

[0014] In S3, the abnormal situation determination methods based on each level of the precision transfer chain include: When the deviation of the target ball measured by the laser tracker when it is repeated exceeds the limit, it indicates that there is a problem with the high-precision reference network; When the deviation between the coordinates of the photogrammetric target sphere solved by photogrammetry and the coordinates given by the laser tracker exceeds the limit, it indicates that there is a problem in the secondary control network link; When the coordinates of the scanned target points obtained by scanning deviate too much from the coordinates given by photogrammetry, it indicates that there is a problem with the local measurement network.

[0015] In S3, the fixes include: Take corresponding repair measures for different links of the precision transfer chain; For high-precision benchmark network problems, the target sphere is measured by rearranging and measuring trackers, and the data of the entire transmission chain is updated; For the secondary control network problem, the photogrammetry target sphere is encrypted, the measurement angle is optimized, and the solution accuracy is improved; For local measurement network problems, the scanning parameters are adjusted to reduce the partition range and increase the overlap.

[0016] In S3, the fixed validation methods include: It includes three aspects: benchmark verification, transfer verification and connection verification; In the benchmark verification phase, it is necessary to re-measure all tracker measurement targets to verify whether the deviation from the original coordinates is within ±0.02mm to confirm the stability of the network structure; In the transfer verification phase, the repaired benchmark is used to recalculate the secondary control network, verify whether the accuracy of the photogrammetry target sphere coordinate solution meets the requirement of ±0.05mm, and check the reliability of the network connection; In the connection verification phase, it is necessary to compare the edge data of the repaired area and the unrepaired area to ensure the smoothness of the transition area and the accuracy of the surface data splicing is controlled within ±0.08mm.

[0017] The present invention has the following beneficial effects: 1. A complete precision transfer system has been established. Through the construction of a multi-level measurement control network, reliable precision transfer from high-precision benchmark to terminal measurement has been achieved, solving the problem of precision assurance in geometric dimension measurement of large turbine rotors.

[0018] 2. Provides a system verification mechanism. The two-way real-time verification mechanism can not only ensure the reliability of the measurement process, but also detect accuracy anomalies in a timely manner, avoiding the defect of traditional methods that problems can only be discovered in the middle and late stages.

[0019] 3. Timely repair of precision problems is achieved. Based on the hierarchical repair strategy of the precision transfer chain, corresponding repair measures can be taken for precision problems in different links, significantly improving measurement efficiency.

[0020] 4. Improved the reliability of measurement data. The complete accuracy transfer, verification and repair mechanism ensures that the final rotor measurement data has traceable accuracy, meeting the measurement needs of large-scale development of hydropower units. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] Figure 1 Flow chart of the implementation of the present invention.

[0023] Figure 2 Schematic diagram of the tracker measurement target sphere layout.

[0024] Figure 3 This is a schematic diagram of the photogrammetry target sphere layout.

[0025] Figure 4 Schematic diagram of the layout of the tracker measurement target sphere, photogrammetry target sphere and scanning target points in adjacent measurement areas. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] See also Figure 1 As shown, a three-dimensional measurement method for a turbine rotor based on a precision transmission chain includes the following steps: S1. Arrange different types of measurement benchmarks on the surface of the turbine rotor, establish a multi-level measurement control network, and form a complete precision transfer network system. Among them, different types of measurement benchmarks include: arranging tracker measurement target balls, photogrammetry target balls and scanning target points on the surface of the turbine rotor, and the multi-level measurement control network includes a high-precision benchmark network, a secondary control network and a local measurement network. In specific implementation, it is necessary to start from the high-precision benchmark network and gradually establish a secondary control network and a local measurement network.

[0028] Methods for establishing a high-precision reference network include: A magnetic base is used to fix the tracker measurement target sphere on the outer circumference of the turbine rotor. Each measurement area can observe more than three tracker measurement target spheres at the same time. The tracker measurement target sphere is measured by a laser tracker to obtain accurate spatial coordinates and establish a high-precision benchmark network.

[0029] For details, see Figure 2 , select a suitable measurement position on the outer circumference of the rotor, and use a magnetic base to fix the tracker to measure the target ball. According to the size of the rotor, 6-12 target balls are arranged at key positions such as the top and bottom of the circumference to ensure that more than 3 target balls can be observed simultaneously in each local measurement area. A laser tracker with a measurement accuracy better than ±0.015mm is used to complete multi-station measurement of these target balls at 5-8 measuring stations. The high-precision spatial coordinate values ​​of the target balls are obtained through least squares adjustment, establishing the highest accuracy benchmark for measurement.

[0030] Methods for establishing a secondary control network include: A magnetic base is used to fix the photogrammetry target sphere on the outer circumference of the turbine rotor. The overlap between the photogrammetry target spheres is maintained at 30%-50%. Images are collected through a global photogrammetry system, and combined with a high-precision reference network, the spatial position of the photogrammetry target sphere is calculated to form a reliable measurement control network.

[0031] For details, see Figure 3 , the coded photogrammetric target balls are arranged on the outer circumferential surface of the rotor, and are also fixed with a magnetic base. The distance between the target balls is controlled at 200-400mm to ensure 30%-50% overlap between adjacent target balls. Using a high-definition industrial camera, image data of 8-12 measuring stations are collected at different angles. Based on the known coordinates of the target balls measured by the tracker, the spatial coordinates of all photogrammetric target balls are obtained by bundle adjustment.

[0032] Methods for establishing a local measurement network include: The entire turbine rotor is divided into several local measurement areas. At least three scanning target points are arranged in each local measurement area. The scanning target points form an effective observation overlap with the surrounding photogrammetry target spheres. A handheld laser scanner is used to identify the scanning target points to achieve scanning positioning, which is used to collect dense surface data of the local area of ​​the rotor outer circumference.

[0033] For details, see Figure 4 , the entire turbine rotor is divided into several local measurement areas. 20-30 reflective label target points, i.e. scanning target points, are arranged in each area to form an effective observation overlap with the surrounding photogrammetry target spheres. A handheld laser scanner with a scanning accuracy better than ±0.03mm is used to identify the scanning target points to achieve scanning positioning and collect dense surface data of the local area of ​​the rotor outer circumference.

[0034] S2. During measurement, a two-way real-time verification measurement mechanism is adopted. This mechanism includes three aspects: forward accuracy transfer, reverse accuracy verification and accuracy transfer verification in adjacent areas, forming a complete accuracy assurance system to ensure the reliability of measurement data.

[0035] The forward precision transfer process is from high precision to low precision; The laser tracker first measures the tracker measurement target sphere to obtain the highest precision benchmark; then, these known high-precision coordinates are used to calibrate the global photogrammetry system, and then the spatial position of the photogrammetry target sphere is solved; finally, the handheld scanner obtains the spatial position of the surface data by identifying the photogrammetry target sphere and the scanning target points on the rotor surface.

[0036] Reverse precision verification is to trace back from low precision to high precision; The scanning accuracy is verified by comparing the deviation of the scanning target point coordinates obtained by the handheld scanner with the coordinates of the photogrammetric target sphere given by photogrammetry, and then the photogrammetric accuracy is verified by comparing the coordinates of the photogrammetric target sphere with the coordinate deviation of the tracker measurement target sphere given by the laser tracker.

[0037] Specifically, in the terminal verification stage, the target point coordinates obtained by scanning need to be compared with the theoretical target point coordinates given by optical measurement, and the deviation shall not exceed ±0.08mm. In the intermediate verification stage, after each set of photogrammetry is completed, the tracker target sphere coordinates obtained by calculation are compared with the coordinates directly measured by the laser tracker, and the deviation should be controlled within ±0.05mm. In the benchmark verification stage, the tracker target sphere needs to be re-measured regularly to ensure that its coordinate stability is within ±0.02mm.

[0038] The accuracy transfer verification methods for adjacent areas include: The overlapping part of the two areas must include the complete precision transfer chain nodes, that is, there must be tracker measurement target sphere, photogrammetry target sphere and scanning target point. By comparing the coordinate consistency of these nodes in the two areas, it is ensured that the accuracy will not be attenuated during the area expansion process.

[0039] Specifically, adjacent measurement areas need to maintain an overlap of 200-300mm, and the overlap area contains at least 2 tracker measurement target balls, 4 photogrammetry target balls, and 8 scanning target points. The coordinate deviation of the same point in the overlap area should not exceed ±0.08mm, and the average deviation of the surface data should be controlled within ±0.05mm.

[0040] S3. Based on the abnormal conditions at each level of the precision transmission chain, repair measures are taken and the repair effect is ensured through verification, thus providing system judgment criteria and repair solutions.

[0041] Among them, the abnormal situation determination methods based on each level of the precision transfer chain include: When the deviation of the laser tracker's repeated measurements of the target sphere exceeds the limit, it indicates that there is a problem with the high-precision reference network.

[0042] Specifically, the laser tracker itself has a coordinate system. When the deviation of the target sphere measured by the laser tracker exceeds the limit, it indicates that there is a problem with the high-precision reference network.

[0043] When the deviation between the coordinates of the photogrammetric target sphere solved by photogrammetry and the coordinates given by the laser tracker exceeds the limit, it indicates that there is a problem in the secondary control network link.

[0044] Specifically, since the photogrammetry target sphere and the tracker measurement target sphere share the same magnetic base, the photogrammetry target sphere and the tracker measurement target sphere are placed in the same position. Therefore, by using the photogrammetry system to scan the photogrammetry target sphere and solve the relative position between the target spheres, the result can be compared with the result calculated by the laser tracker.

[0045] When the coordinates of the scanned target points obtained by scanning deviate too much from the coordinates given by photogrammetry, it indicates that there is a problem with the local measurement network.

[0046] Specifically, there are marking points on the photogrammetry target sphere, which can also be measured using a handheld scanner. Therefore, the handheld scanner can also solve the relative positions of these points. If the deviation from the photogrammetry solution is large, then there is a problem.

[0047] In this embodiment, in the high-precision reference network link, when the tracker measures the target ball with a repeated measurement deviation exceeding 0.02 mm, it is determined to be abnormal; In this embodiment, in the secondary control network link, when the deviation between the target sphere coordinates solved by photogrammetry and the coordinates given by the tracker exceeds 0.05 mm, it is determined to be abnormal; In this embodiment, in the local measurement network link, when the deviation between the target point coordinates obtained by scanning and the coordinates given by photogrammetry exceeds 0.08 mm, it is determined to be abnormal.

[0048] The fixes include: Take corresponding repair measures for different links of the precision transfer chain; For high-precision benchmark network problems, the target sphere is measured by rearranging and measuring trackers, and the data of the entire transmission chain is updated; For the secondary control network problem, the photogrammetry target sphere is encrypted, the measurement angle is optimized, and the solution accuracy is improved; For local measurement network problems, the scanning parameters are adjusted to reduce the partition range and increase the overlap.

[0049] Specifically, for high-precision benchmark network link problems, it is necessary to check and adjust the fixation of the magnetic base, increase the number of measurement stations for the tracker to measure the target ball, such as adding 2-3 measurement stations on the original basis, and rearrange and measure the tracker to measure the target ball when necessary. For secondary control network link problems, it is necessary to add 2-3 photogrammetric target balls in the area with abnormal accuracy, take 2-4 new station images, optimize the photogrammetric network structure, and re-perform the overall adjustment solution. For terminal local measurement network link problems, it is necessary to adjust the scanning parameters, such as increasing the point cloud density from the original 0.5mm to 0.3mm, reducing the single scanning area, such as from 0.5m×0.5m to 0.3m×0.3m, and increasing the area overlap, such as from 30% to 50%.

[0050] The fixed verification methods include: It includes three aspects: benchmark verification, transfer verification and connection verification; In the benchmark verification phase, it is necessary to re-measure all tracker measurement targets to verify whether the deviation from the original coordinates is within ±0.02mm to confirm the stability of the network structure; In the transfer verification phase, the repaired benchmark is used to recalculate the secondary control network, verify whether the accuracy of the photogrammetry target sphere coordinate solution meets the requirement of ±0.05mm, and check the reliability of the network connection; In the connection verification phase, it is necessary to compare the edge data of the repaired area and the unrepaired area to ensure the smoothness of the transition area, that is, the curvature is continuous, and the surface data splicing accuracy is controlled within ±0.08mm.

[0051] Through the above steps, the present invention realizes high-precision measurement of turbine rotors and establishes a complete precision transfer system. Through the construction of a multi-level measurement control network, reliable precision transfer from high-precision benchmark to terminal measurement is realized, solving the problem of precision guarantee of geometric dimension measurement of large turbine rotors; through the two-way real-time verification mechanism, not only the reliability of the measurement process is guaranteed, but also precision anomalies can be discovered in time, avoiding the defect that problems can only be discovered in the middle and late stages of traditional methods; the hierarchical repair strategy based on the precision transfer chain can take corresponding repair measures for precision problems in different links, significantly improving the measurement efficiency; the complete precision transfer, verification and repair mechanism ensures that the final turbine rotor data has traceable precision guarantee. This measurement method is particularly suitable for surface detection of large turbine parts, and can efficiently and accurately complete surface measurement tasks, significantly improving measurement efficiency and data reliability.

Claims

1. A three-dimensional measurement method for a turbine rotor based on a precision transmission chain, characterized in that: The following steps are involved: S1. Arrange different types of measurement benchmarks on the surface of the turbine rotor and establish a multi-level measurement control network; wherein the different types of measurement benchmarks include: arranging a tracker measurement target sphere, a photogrammetry target sphere and a scanning target point on the surface of the turbine rotor, and the multi-level measurement control network includes a high-precision benchmark network, a secondary control network and a local measurement network; S2. During measurement, a two-way real-time verification measurement mechanism is used to ensure the reliability of the measurement data by combining forward accuracy transfer and reverse accuracy verification, as well as accuracy transfer verification in adjacent areas; S3. Take repair measures based on the abnormal conditions at each level of the precision transfer chain and ensure the repair effect through verification.

2. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S1, the method of establishing a high-precision benchmark network includes: A magnetic base is used to fix the tracker measurement target sphere on the outer circumference of the turbine rotor. Each measurement area can observe more than three tracker measurement target spheres at the same time. The tracker measurement target sphere is measured by a laser tracker to obtain accurate spatial coordinates and establish a high-precision benchmark network.

3. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1 is characterized in that: In S1, the method of establishing a secondary control network includes: A magnetic base is used to fix the photogrammetry target sphere on the outer circumference of the turbine rotor. The overlap between the photogrammetry target spheres is maintained at 30%-50%. Images are collected through a global photogrammetry system, and combined with a high-precision reference network, the spatial position of the photogrammetry target sphere is calculated to form a reliable measurement control network.

4. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S1, the method of establishing a local measurement network includes: The entire turbine rotor is divided into several local measurement areas. At least three scanning target points are arranged in each local measurement area. The scanning target points form an effective observation overlap with the surrounding photogrammetry target spheres. A handheld laser scanner is used to identify the scanning target points to achieve scanning positioning, which is used to collect dense surface data of the local area of ​​the rotor outer circumference.

5. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S2, the forward precision transfer process is from high precision to low precision; Among them, the laser tracker first measures the target sphere to obtain the highest precision benchmark, and then uses these known high-precision coordinates to calibrate the global photogrammetry system, and then solves the spatial position of the photogrammetry target sphere. Finally, the handheld scanner obtains the spatial position of the surface data by identifying the scanning target points on the photogrammetry target sphere and the rotor surface.

6. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S2, reverse precision verification is to trace back from low precision to high precision; Among them, the scanning accuracy is verified by comparing the deviation of the scanning target point coordinates obtained by the handheld scanner with the photogrammetry target sphere coordinates given by photogrammetry, and then the photogrammetry accuracy is verified by comparing the photogrammetry target sphere coordinates with the tracker measurement target sphere coordinate deviation given by the laser tracker.

7. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S2, the accuracy transfer verification method of adjacent areas includes: The overlapping part of the two areas must include the complete precision transfer chain nodes, that is, there must be tracker measurement target sphere, photogrammetry target sphere and scanning target point. By comparing the coordinate consistency of these nodes in the two areas, it is ensured that the accuracy will not be attenuated during the area expansion process.

8. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S3, the abnormal situation determination methods based on each level of the precision transfer chain include: When the deviation of the target ball measured by the laser tracker when it is repeated exceeds the limit, it indicates that there is a problem with the high-precision reference network; When the deviation between the coordinates of the photogrammetric target sphere solved by photogrammetry and the coordinates given by the laser tracker exceeds the limit, it indicates that there is a problem in the secondary control network link; When the coordinates of the scanned target points obtained by scanning deviate too much from the coordinates given by photogrammetry, it indicates that there is a problem with the local measurement network.

9. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S3, the fixes include: Take corresponding repair measures for different links of the precision transfer chain; For high-precision benchmark network problems, the target sphere is measured by rearranging and measuring trackers, and the data of the entire transmission chain is updated; For the secondary control network problem, the photogrammetry target sphere is encrypted, the measurement angle is optimized, and the solution accuracy is improved; For local measurement network problems, the scanning parameters are adjusted to reduce the partition range and increase the overlap.

10. The method for three-dimensional measurement of a turbine rotor based on a precision transmission chain according to claim 1, characterized in that: In S3, the fixed verification methods include: It includes three aspects: benchmark verification, transfer verification and connection verification; In the benchmark verification phase, it is necessary to re-measure all tracker measurement targets to verify whether the deviation from the original coordinates is within ±0.02mm to confirm the stability of the network structure; In the transfer verification phase, the repaired benchmark is used to recalculate the secondary control network, verify whether the accuracy of the photogrammetry target sphere coordinate solution meets the requirement of ±0.05mm, and check the reliability of the network connection; In the connection verification phase, it is necessary to compare the edge data of the repaired area and the unrepaired area to ensure the smoothness of the transition area and the accuracy of the surface data splicing is controlled within ±0.08mm.

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