Cooperative measurement method and system for laser tracker and three-dimensional scanner

Abstract

The invention provides a cooperative measurement method and system for a laser tracker and a three-dimensional scanner, and the method comprises the following steps: designing a three-dimensional scanner clamp: designing the clamp, and placing a target ball; converting a measurement coordinate system of the three-dimensional scanner and a clamp coordinate system; calibrating a pose, namely a homogeneous transformation matrix, of the measurement coordinate system of the scanner relative to the measurement coordinate system of the laser tracker, and calibrating poses, namely homogeneous transformation matrixes, of the measurement coordinate system of the laser tracker and the clamp coordinate system; calibrating a pose, namely a homogeneous transformation matrix, of the scanner measurement coordinate system relative to the clamp coordinate system; a scanner clamp and equipment are installed, wherein the scanner clamp is installed, and a laser tracker and a laser scanner are installed; according to the working process, a laser tracker and three-dimensional scanner cooperative measurement method is used for carrying out high-precision measurement on a large-size cylinder section product. According to the technical scheme, the technical problems that in the prior art, a single measurement method has measurement limitation, and the measurement precision and the view field range are difficult to guarantee at the same time are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-precision automated measurement of large components, and in particular to a collaborative measurement method and system of a laser tracker and a three-dimensional scanner. Background Art

[0002] With the development of the industrial field, the requirements for large-scale measurement technology are getting higher and higher. The positioning and measurement space range of large-scale complex precision structure products is large, ranging from several meters to more than ten meters, and the relative accuracy requirements of local areas are relatively high. The global measurement range is large and the positioning reference requirements are high. For high-precision measurement of local areas in multiple positions under different scale ranges, it is necessary to complete the precise positioning of the posture under a large range and the high-precision scanning of the surface shape of a small local area. The traditional single measurement method has measurement limitations and it is difficult to guarantee the measurement accuracy and field of view at the same time.

[0003] 3D scanners have the advantages of fast measurement speed, high accuracy, high efficiency and good flexibility, which can meet the needs of online measurement and efficient measurement. However, the field of view of a single measurement of a high-precision 3D scanner is usually small, and multiple station transfers are required to achieve large-scale measurement. After multiple station transfers, the measurement accuracy is low. The laser tracker has a long distance measurement and high accuracy, but the measurement data density is low, which makes it difficult to directly apply it to the measurement of large-scale product geometric surfaces. Obviously, a single measurement method faces the contradiction between measurement accuracy and field of view. Summary of the invention

[0004] The present invention provides a laser tracker and a three-dimensional scanner collaborative measurement method and system, which can solve the technical problem that a single measurement method in the prior art has measurement limitations and is difficult to simultaneously ensure measurement accuracy and field of view.

[0005] According to one aspect of the present invention, a laser tracker and a three-dimensional scanner collaborative measurement method is provided, and the laser tracker and the three-dimensional scanner collaborative measurement method comprises: step 1, designing a three-dimensional scanner fixture and placing it on a scanner tracker, and placing at least four target ball seats on the three-dimensional scanner fixture; step 2, converting the measurement coordinate system of the three-dimensional scanner and the fixture coordinate system: placing a common target ball seat on a smooth plane, the common target ball seat forming a common target ball seat coordinate system, placing target points that can be recognized by the laser tracker and the three-dimensional scanner respectively, and obtaining a coordinate transformation matrix T between the three-dimensional scanner measurement coordinate system and the laser tracker measurement coordinate system sl Then, the laser tracker is used to measure the fixture target point to obtain the coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system bl , according to the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the laser tracker measurement coordinate system sl The coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system blCalculate and obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system sb ; Step 3, install the fixture on the tracker of the 3D scanner, install the laser tracker and the 3D scanner, and install the public target ball seat; Step 4, use the 3D scanner to scan the public measurement area identification point target ball, and at the same time, the laser tracker measures the laser target ball on the scanner tracker fixture, replace the public area identification point target ball with the laser target ball, and use the laser tracker to measure the laser target ball; use the scanner to perform laser scanning measurement on the two areas of the product to be measured; use the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system obtained in step 2 sb The coordinates of the two segments of point cloud data measured by the 3D scanner are processed, and the processed data are converted to the global coordinate system to achieve overall data splicing and complete the collaborative measurement of the laser tracker and the 3D scanner.

[0006] Furthermore, in step one, a global measurement coordinate system is established using a laser tracker, the measurement coordinate system of the three-dimensional scanner is located on the scanner tracker, and the designed fixture is placed on the scanner tracker; at least four target ball seats are placed on the fixture, the distribution positions of the four target ball seats should not be collinear, and the angle of the triangle formed by every three target ball seats should not be greater than 120 degrees.

[0007] Furthermore, step 2 specifically includes: placing at least four common target ball seats on a smooth plane, and the common target ball seats constitute a common target ball seat coordinate system O t X t Y t Z t , to ensure that the placement position can be recognized by both the laser tracker and the 3D scanner; first place a laser target ball that can be recognized by the laser tracker on the target ball seat, obtain the position of the target point, and the laser tracker optical target point Q il , il=1, 2, …, nl (il≥4); then replace the laser target ball with a special target ball with a marker that can be recognized by a 3D scanner, use a 3D scanner to fit the center of each target ball, obtain the position of the target point, and the laser scanner optical marker point Q is , is=1,2,…,ns(is≥4); according to the optical target point Q il The laser tracker measures the coordinate system O l X l Y l Z l The observed data P il Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Yl Z l The transformation matrix T between tl ; According to the laser scanner optical marker point Q is And laser scanner optical marker Q is Measuring coordinate system O in 3D scanner s X s Y s Z s The observed data P is Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The transformation matrix T between ts ; According to the common target ball seat coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl With the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The transformation matrix T between ts Calculate and obtain the 3D scanner measurement coordinate system O s X s Y s Z s Measure coordinate system O with laser tracker l X l Y l Z l The coordinate transformation matrix T sl ; Use the laser tracker to complete the measurement of the target on the fixture coordinate system. Set the optical target point Q on the target on the fixture ib The laser tracker measures the coordinate system O l X l Y l Z l The observed data is P ib , according to the optical target point Q ib And the observation data P ib Calculate and obtain the fixture coordinate system Ob X b Y b Z b Measure coordinate system O with laser tracker l X l Y l Z l The coordinate transformation matrix T between bl ; According to the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the laser tracker measurement coordinate system sl The coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system bl Calculate and obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system sb .

[0008] Further, according to the optical target point Q il The laser tracker measures the coordinate system O l X l Y l Z l The observed data P il Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl Specifically include: According to P il =R tl Q il +M tl Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The rotation transformation matrix R tl And the translation matrix M tl ; According to the common target ball seat coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The rotation transformation matrix R tl And the translation matrix M tl Calculate and obtain the common target sphere coordinate system Ot X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl .

[0009] Further, according to the laser scanner optical marking point Q is And laser scanner optical marker Q is Measuring coordinate system O in 3D scanner s X s Y s Z s The observed data R is Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The transformation matrix T between ts Specifically include: According to P is =R ts Q is +M ts Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The rotation transformation matrix R ts And the translation matrix M ts ; According to the common target ball seat coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The rotation transformation matrix R ts And the translation matrix M ts Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Ys Z s The transformation matrix T between ts .

[0010] Furthermore, the three-dimensional scanner measures the coordinate system O s X s Y s Z s Measure coordinate system O with laser tracker l X l Y l Z l The coordinate transformation matrix T sl According to T sl =T tl ×T ts -1 Calculate acquisition.

[0011] Furthermore, the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system is sb According to T sb =T bl -1 ×T sl =T bl -1 ×T tl ×T ts -1 Calculate acquisition.

[0012] Furthermore, step three specifically includes: installing the clamp on the tracker of the 3D scanner, and firmly connecting the clamp to the tracker of the 3D scanner by tightening bolts; installing the laser tracker and the 3D scanner; installing the public target ball mounts, and the 4 public target ball mounts should be placed in the public measurement area, with a set distance from the two device hosts, and the opening directions of the 4 laser target balls and the marking point target balls should be easily recognized by the laser tracker and the 3D scanner.

[0013] Furthermore, step four specifically includes: using a 3D scanner to scan the public measurement area identification point target ball, while the laser tracker measures the laser target ball on the scanner tracker fixture, replacing the public area identification point target ball with the laser target ball, using the laser tracker to measure the laser target ball, and automatically importing the three sets of data into the calibration algorithm in the measurement software to realize the calibration of the measurement coordinate system of the 3D scanner and the fixture coordinate system, and then converting the measurement coordinate system of the scanner to the global coordinate system; using the scanner, performing laser scanning and measurement on the two areas respectively, while the laser tracker tracks and measures the laser target ball on the scanner tracker fixture, and after the scanning is completed, the measurement software automatically converts the coordinates of the two segments of point cloud data obtained by the scanner to the global coordinate system to achieve overall splicing.

[0014] According to another aspect of the present invention, a laser tracker and three-dimensional scanner collaborative measurement system is provided, which uses the laser tracker and three-dimensional scanner collaborative measurement method as described above to perform collaborative testing.

[0015] By applying the technical solution of the present invention, a laser tracker and a three-dimensional scanner collaborative measurement method is provided. The method adopts a laser tracker and a three-dimensional scanner to jointly participate in the data acquisition process. The combined measurement can optimize a series of problems existing in the measurement process of the measuring instrument, such as the large number of station transfers, complex environmental changes, long measurement cycles, and limited measurement space. The measuring instruments complement each other's advantages, improve the system measurement capability, and improve the measurement accuracy and efficiency. Taking the spatial measurement of large-scale barrel products as an example, the barrel is divided into multiple local measurement intervals. In order to achieve local precise processing and installation, there are high requirements for the information type and accuracy of local measurements. At the same time, it is also necessary to integrate and splice the data of the local measurement intervals so that the global coordination across sizes meets the error tolerance requirements. Therefore, the digital combined collaborative measurement of the laser tracker and the three-dimensional scanner, the construction of a large-scale space high-precision measurement field, and the high-precision measurement requirements of large-scale product assembly site automation, regional division, and cross-scale have become key issues that cannot be avoided in the manufacturing process of large-scale products. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic diagram of a scanner fixture provided according to a specific embodiment of the present invention is shown.

[0018] Figure 2 A schematic diagram of a collaborative measurement scenario of a laser tracker and a three-dimensional scanner provided according to a specific embodiment of the present invention is shown;

[0019] Figure 3 A schematic diagram of the calibration principle of a base coordinate system provided according to a specific embodiment of the present invention is shown. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0022] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0023] like Figure 1 and Figure 2 As shown, according to a specific embodiment of the present invention, a laser tracker and a three-dimensional scanner collaborative measurement method is provided, and the laser tracker and the three-dimensional scanner collaborative measurement method comprises: step one, designing a three-dimensional scanner fixture and placing it on the scanner tracker, and placing at least four target ball seats on the three-dimensional scanner fixture; step two, converting the measurement coordinate system of the three-dimensional scanner and the fixture coordinate system: placing a common target ball seat on a smooth plane, the common target ball seat forming a common target ball seat coordinate system, placing target points that can be recognized by the laser tracker and the three-dimensional scanner respectively, and obtaining a coordinate transformation matrix T between the three-dimensional scanner measurement coordinate system and the laser tracker measurement coordinate system. slThen, the laser tracker is used to measure the fixture target point to obtain the coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system bl , according to the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the laser tracker measurement coordinate system sl The coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system bl Calculate and obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system sb ; Step 3, install the fixture on the tracker of the 3D scanner, install the laser tracker and the 3D scanner, and install the public target ball seat; Step 4, use the 3D scanner to scan the public measurement area identification point target ball, and at the same time, the laser tracker measures the laser target ball on the scanner tracker fixture, replace the public area identification point target ball with the laser target ball, and use the laser tracker to measure the laser target ball; use the scanner to perform laser scanning measurement on the two areas of the product to be measured; use the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system obtained in step 2 sb The coordinates of the two segments of point cloud data measured by the 3D scanner are processed, and the processed data are converted to the global coordinate system to achieve overall data splicing and complete the collaborative measurement of the laser tracker and the 3D scanner.

[0024] By applying this configuration, a laser tracker and a three-dimensional scanner collaborative measurement method is provided. The method uses a laser tracker and a three-dimensional scanner to jointly participate in the data acquisition process. The combined measurement can optimize a series of problems existing in the measurement process of the measuring instrument, such as the large number of station transfers, complex environmental changes, long measurement cycles, and limited measurement space. The measuring instruments complement each other's advantages, improve the system measurement capability, and improve the measurement accuracy and efficiency. Taking the spatial measurement of large-size barrel products as an example, the barrel is divided into multiple local measurement intervals. In order to achieve local precise processing and installation, there are high requirements for the information type and accuracy of local measurements. At the same time, it is also necessary to integrate and splice the data of the local measurement intervals so that the global coordination across sizes meets the error tolerance requirements. Therefore, the digital combination and collaborative measurement of the laser tracker and the three-dimensional scanner, the construction of a large-size space high-precision measurement field, and the high-precision measurement requirements of large-size barrel product assembly site automation, regional division, and cross-scale have become key issues that cannot be avoided in the manufacturing process of large-size products.

[0025] Among them, in step one, a global measurement coordinate system is established using a laser tracker, the measurement coordinate system of the 3D scanner is located on the scanner tracker, and the designed fixture is placed on the scanner tracker; at least four target ball seats are placed on the fixture, the distribution positions of the four target ball seats should not be collinear, and the angle of the triangle formed by every three target ball seats should not be greater than 120 degrees.

[0026] Furthermore, in order to obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system sb Step 2 specifically includes: placing at least 4 public target sphere seats on a smooth plane, and the public target sphere seats constitute a public target sphere seat coordinate system O t X t Y t Z t , to ensure that the placement position can be recognized by both the laser tracker and the 3D scanner; first place a laser target ball that can be recognized by the laser tracker on the target ball seat, obtain the position of the target point, and the laser tracker optical target point Q il , il=1, 2, …, nl (il≥4); then replace the laser target ball with a special target ball with a marker that can be recognized by a 3D scanner, use a 3D scanner to fit the center of each target ball, obtain the position of the target point, and the laser scanner optical marker point Q is , is=1,2,…,ns(is≥4); according to the optical target point Q il and the optical target point Q il The laser tracker measures the coordinate system O l X l Y l Z l The observed data P il Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl ; According to the laser scanner optical marker point Q is And laser scanner optical marker Q is Measuring coordinate system O in 3D scanner s X s Y s Z s The observed data P is Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The transformation matrix T between ts ; According to the common target ball seat coordinate system O t X t Y t Z tMeasure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl With the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The transformation matrix T between ts Calculate and obtain the 3D scanner measurement coordinate system O s X s Y s Z s Measure coordinate system O with laser tracker l X l Y l Z l The coordinate transformation matrix T sl ; Use the laser tracker to complete the measurement of the target on the fixture coordinate system. Set the optical target point Q on the target on the fixture ib The laser tracker measures the coordinate system O l X l Y l Z l The observed data is P ib , according to the optical target point Q ib And the observation data P ib Calculate and obtain the fixture coordinate system O b X b Y b Z b Measure coordinate system O with laser tracker l X l Y l Z l The coordinate transformation matrix T between bl ; According to the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the laser tracker measurement coordinate system sl The coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system bl Calculate and obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system sb .

[0027] According to the optical target point Q il and the optical target point Q il The laser tracker measures the coordinate system O l X l Y l Z lThe observed data P il Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl Specifically include: According to P il =R tl Q il +M tl Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The rotation transformation matrix R tl And the translation matrix M tl ; According to the common target ball seat coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The rotation transformation matrix R tl And the translation matrix M tl Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl .

[0028] According to the laser scanner optical marker point Q is And laser scanner optical marker Q is Measuring coordinate system O in 3D scanner s X s Y s Z s The observed data P is Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanners X s Y s Z s The transformation matrix T between ts Specifically include: According to P is =R ts Q is +M ts Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The rotation transformation matrix R ts And the translation matrix M ts ; According to the common target ball seat coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The rotation transformation matrix R ts And the translation matrix M ts Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The transformation matrix T between ts .

[0029] 3D scanner measurement coordinate system O s X s Y s Z s Measure coordinate system O with laser tracker l X l Y l Z l The coordinate transformation matrix T sl According to T sl =T tl ×T ts -1 Calculate and obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system sb According to T sb =T bl -1 ×T sl =Tbl -1 ×T tl ×T ts -1 Calculate acquisition.

[0030] After obtaining the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system sb , the scanner fixture, equipment, and target ball seat can be installed. In the present invention, step three specifically includes: installing the fixture on the tracker of the 3D scanner, and firmly connecting the fixture to the tracker of the 3D scanner by tightening bolts; installing the laser tracker and the 3D scanner; installing the public target ball seat, and the four public target ball seats should be placed in the public measurement area, with a set distance from the two equipment hosts, and the opening directions of the four laser target balls and the marking point target ball should be easily recognized by the laser tracker and the 3D scanner.

[0031] Furthermore, after the scanner fixture, equipment, and target ball seat are installed, the workpiece measurement can be started. In the present invention, step four specifically includes: using a three-dimensional scanner to scan the target ball of the common measurement area identification point, while the laser tracker measures the laser target ball on the scanner tracker fixture, replacing the target ball of the common area identification point with the laser target ball, using the laser tracker to measure the laser target ball, and automatically importing the three sets of data into the calibration algorithm in the measurement software to realize the calibration of the measurement coordinate system of the three-dimensional scanner and the fixture coordinate system, and then converting the measurement coordinate system of the scanner to the global coordinate system; using the scanner, laser scanning and measuring the two areas respectively, while the laser tracker tracks and measures the laser target ball on the scanner tracker fixture, and after the scanning is completed, the measurement software automatically converts the coordinates of the two segments of point cloud data obtained by the scanner to the global coordinate system to achieve overall splicing.

[0032] According to another aspect of the present invention, a laser tracker and three-dimensional scanner collaborative measurement system is provided, which uses the laser tracker and three-dimensional scanner collaborative measurement method as described above to perform collaborative testing.

[0033] By applying this configuration, a laser tracker and a three-dimensional scanner collaborative measurement system is provided. The system uses a laser tracker and a three-dimensional scanner to jointly participate in the data acquisition process. The combined measurement can optimize a series of problems existing in the measurement process of the measuring instrument, such as the large number of station transfers, complex environmental changes, long measurement cycles, and limited measurement space. The measuring instruments complement each other's advantages, improve the system's measurement capabilities, and improve measurement accuracy and efficiency. Taking the spatial measurement of large-size barrel products as an example, the barrel is divided into multiple local measurement intervals. In order to achieve local precise processing and installation, there are high requirements for the information type and accuracy of local measurements. At the same time, it is also necessary to integrate and splice the data of the local measurement intervals so that the global coordination across dimensions meets the error tolerance requirements. Therefore, the digital combined collaborative measurement of the laser tracker and the three-dimensional scanner, the construction of a large-size space high-precision measurement field, and the high-precision measurement requirements of large-size barrel product assembly site automation, regional division, and cross-scale have become key issues that cannot be avoided in the manufacturing process of large-size products.

[0034] In order to further understand the present invention, the following Figure 1 , Figure 2 and Figure 3 The laser tracker and three-dimensional scanner collaborative measurement method provided by the present invention are described in detail.

[0035] like Figure 1 , Figure 2 and Figure 3 As shown, according to a specific embodiment of the present invention, a laser tracker and a three-dimensional scanner collaborative measurement method is provided, and the method specifically includes the following steps.

[0036] 1) Design a 3D scanner fixture. The fixture is designed to be placed on the scanner tracker. At least 4 target spheres can be placed on the fixture. The distribution positions of the 4 target spheres should not be collinear. The angle of the triangle formed by every 3 target spheres should not be greater than 120 degrees. The distance between two target spheres should not be too small.

[0037] 2) Conversion between the measurement coordinate system of the 3D scanner and the fixture coordinate system. Place the common target sphere on a smooth plane. The common target sphere forms a common target sphere coordinate system. Place target points that can be recognized by the laser tracker and the 3D scanner respectively, and obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the laser tracker measurement coordinate system. sl Then, the laser tracker is used to measure the fixture target point to obtain the coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system bl , according to the coordinate transformation matrix T between the three-dimensional scanner measurement coordinate system and the laser tracker measurement coordinate system sl The coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system blCalculate and obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system sb ;

[0038] 3) Installation of scanner fixture, equipment, and target ball seat. Install the fixture on the tracker of the 3D scanner, install the laser tracker and 3D scanner, and install the common target ball seat;

[0039] 4) Software functions. The software should have functions such as controlling the scanner and tracker to collect data, adjusting measurement parameters, and data processing;

[0040] 5) Workflow. Use a 3D scanner to scan the target ball marking the public measurement area, and at the same time, use a laser tracker to measure the laser target ball on the scanner tracker fixture. Replace the target ball marking the public area with the laser target ball, and use a laser tracker to measure the laser target ball. Use a scanner to perform laser scanning and measurement on the two areas respectively. Perform data processing and analysis on the overall point cloud data and output an analysis report.

[0041] The steps of designing the 3D scanner fixture are as follows:

[0042] 1) Design the fixture and place it on the scanner tracker. Use the laser tracker to establish a global measurement coordinate system. The measurement coordinate system of the 3D scanner is located on its tracker, so the designed fixture is placed on the scanner tracker;

[0043] 2) Design the distribution position of the target ball seats. At least 4 target ball seats can be placed on the fixture. The distribution positions of the 4 target ball seats should not be collinear. The angle of the triangle formed by every 3 target ball seats should not be greater than 120 degrees, and the distance between the two target seats should not be too small.

[0044] The conversion steps between the measurement coordinate system of the 3D scanner and the fixture coordinate system are as follows:

[0045] 1) Calibrate the position and posture of the scanner measurement coordinate system relative to the laser tracker measurement coordinate system, that is, the homogeneous transformation matrix.

[0046] The coordinate transformation relationship between any two coordinate systems is:

[0047]

[0048] Where T is the homogeneous coordinate transformation matrix; R is the Euler angle ω rotating around the three coordinate axes x ,ω y and ω z Represents the rotation transformation matrix; M is the translation component t in the three coordinate directions x , t y and t z Represents the translation vector; T has a strict corresponding relationship with R and M.

[0049] In order to realize the positioning and tracking of the scanner posture, it is necessary to track the target ball of the fixture on the scanner. Let the target ball constitute the fixture coordinate system target point Q ib , ib=1, 2, ..., nb (ib≥4), and establish the scanner fixture coordinate system O through these target points b X b Y b Z b .Q ib In O b X b Y b Z b The coordinate system is labeled (X ib , Y ib , Z ib ). During the calibration and measurement process, the laser tracker locates and tracks the scanner's position by observing the target point of the fixture coordinate system.

[0050] The fixture coordinate system calibration is used to establish the conversion relationship between the scanner measurement coordinate system and the fixture coordinate system. Place at least 4 common target sphere seats on a smooth plane, and the common target sphere seats constitute the common target sphere seat coordinate system O t X t Y t Z t , to ensure that the placement position can be recognized by both the laser tracker and the 3D scanner, first place a laser target ball that can be recognized by the laser tracker on the target ball seat, obtain the position of the target point, and the laser tracker optical target point Q il , il=1, 2, …, nl (il≥4). Then replace the laser target ball with a special target ball with a marker that can be recognized by a 3D scanner. Use a 3D scanner to fit the center of each target ball and obtain the position of the target point. The laser scanner optical marker point Q is ,is=1,2,…,ns(is≥4).

[0051] The centers of the two target points are at O t X t Y t Z t The coordinates of the coordinate system are recorded as (X il , Y il , Z il ) and (X is , Y is , Z is ), which are identified and observed by the laser tracker and 3D scanner respectively during the calibration process. Let the optical target point Q il In the tracker measurement coordinate system O l X l Y l Z l The observed data is P il, then the process satisfies the following observation equation:

[0052] P il =R tl Q il +M tl ;il=1,2,…,nl Formula (2)

[0053] Where R tl With M tl O t X t Y t Z t Coordinate system and O l X l Y l Z l The rotation transformation matrix and translation matrix between coordinate systems. According to the rotation transformation matrix R tl With the translation matrix M tl , combined with formula (1), we can get T tl .

[0054] Similarly, let the optical mark point Q is Measuring coordinate system O in 3D scanner s X s Y s Z s The observed data is P is , then the process satisfies the following observation equation:

[0055] P is =R ts Q is +M ts ;is=1,2,…,ns Formula (3)

[0056] Where R ts O t X t Y t Z t Coordinate system and O s X s Y s Z s The rotation transformation matrix between coordinate systems and M ts O t X t Y t Z t Coordinate system and O s X s Y s Z s The translation matrix between coordinate systems. According to the rotation transformation matrix R ts With the translation matrix M ts , combined with formula (1), we can get Tts .

[0057] Therefore, the laser tracker measures the coordinate system O l X l Y l Z l Measuring coordinate system O with laser scanner s X s Y s Z s The coordinate transformation matrix between is:

[0058] T sl =T tl ×T ts -1 Formula (4)

[0059] 2) Calibrate the position and posture of the laser tracker measurement coordinate system and the fixture coordinate system, that is, the homogeneous transformation matrix. Use the laser tracker to complete the measurement of the target in the fixture coordinate system. Suppose the optical target point Q on the target on the fixture is ib In O l X l Y l Z l The observation data of the coordinate system is P ib , then the process satisfies the following observation equation:

[0060] P ib =R bl Q ib +M bl ;ib=1,2,…,nb Formula (5)

[0061] Where R bl O b X b Y b Z b Coordinate system and O l X l Y l Z l The rotation transformation matrix between coordinate systems, M bl O b X b Y b Z b Coordinate system and O l X l Y l Z l The translation matrix between coordinate systems. According to the rotation transformation matrix R bl With the translation matrix M bl , combined with formula (1), we can get T bl .

[0062] 3) Calibrate the position and posture of the scanner measurement coordinate system relative to the fixture coordinate system, that is, the homogeneous transformation matrix. The three-dimensional scanner measurement coordinate system O is obtained through the mathematical calculation relationship between 1) and 2). s X s Y s Z s With fixture coordinate system O b X b Y b Z b The coordinate transformation matrix between is:

[0063] T sb =T bl -1 ×T sl =T bl -1 ×T tl ×T ts -1 Formula (6)

[0064] The software function steps described are:

[0065] The laser tracker is equipped with measurement software, which has the functions of controlling the laser tracker and processing data. The 3D scanner is equipped with 3D scanning acquisition software and data analysis software, which has the functions of equipment control and data processing. In order to facilitate operation and improve the degree of automation, the software functions of the two devices should be integrated into one software. The software should use the device's own SDK development package, and have the functions of controlling the scanner and tracker to collect data, adjusting measurement parameters, and data processing. At the same time, the measurement software should also reserve a communication interface to facilitate subsequent communication with other types of equipment. The calibration algorithm of the measurement coordinate system of the 3D scanner and the fixture coordinate system should be integrated in the measurement software.

[0066] Installation steps of fixtures and equipment:

[0067] Fix the fixture to the tracker of the 3D scanner by tightening the bolts, install the laser target ball according to the form of 5.1, place the laser tracker and the 3D scanner in a suitable position, the distance between the two devices is about 2 meters, and the base of the device is firmly supported. The 4 public target ball seats should be placed in the public measurement area, about 2 meters away from the two device hosts. The opening direction of the 4 laser target balls and the mark point target ball should be easily recognized by the laser tracker and the 3D scanner. During the calibration measurement process, keep the surrounding environment stable, without noise and vibration, and the equipment and the public target ball seats shall not be moved at will. The computer is connected to the laser tracker host and the 3D scanner host through cables, so that the measurement data obtained by the tracker host is transmitted to the scanning measurement software of the 3D scanner to realize the real-time splicing of point cloud data. Ensure that the curvature radius of the device signal cable is greater than 140mm and avoid cable crossing; ensure that the cable connector pins are not bent. After the equipment is installed and connected, turn on the laser tracker and 3D scanner to preheat for at least 20 minutes.

[0068] The described workflow steps:

[0069] The above method is used to perform high-precision measurement on large-size products. The length of large-size products is greater than 10m, so the single-frame field of view of the scanner is not enough, so the scanning process is divided into two areas.

[0070] 1) Use a 3D scanner to scan the target ball of the public measurement area mark point, and at the same time, the laser tracker measures the laser target ball on the scanner tracker fixture. Replace the target ball of the public area mark point with the laser target ball, and use the laser tracker to measure the laser target ball. The three sets of data are automatically imported into the calibration algorithm in the measurement software to realize the calibration of the measurement coordinate system of the 3D scanner and the fixture coordinate system, and then convert the measurement coordinate system of the scanner to the global coordinate system.

[0071] 2) Use a scanner to perform laser scanning and measurement on the two areas respectively, and at the same time, the laser tracker tracks and measures the laser target ball on the scanner tracker fixture. After the scanning is completed, the measurement software automatically converts the coordinates of the two segments of point cloud data obtained by the scanner into the global coordinate system to achieve overall splicing.

[0072] 3) Process and analyze the overall point cloud data and output an analysis report.

[0073] The advantages of the present invention are: 1) it can realize the complementary advantages between laser trackers and three-dimensional scanner equipment; 2) it can realize high-precision measurement of large-scale product assembly site automation, regional division, and cross-scale.

[0074] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0075] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A laser tracker and three-dimensional scanner collaborative measurement method, characterized in that: The laser tracker and three-dimensional scanner collaborative measurement method comprises: Step 1, designing a 3D scanner fixture and placing it on a scanner tracker, wherein at least 4 target ball seats are placed on the 3D scanner fixture; Step 2: Conversion between the measurement coordinate system of the 3D scanner and the fixture coordinate system: Place a common target sphere seat on a smooth plane. The common target sphere seat forms a common target sphere seat coordinate system. Place target points that can be recognized by the laser tracker and the 3D scanner respectively to obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the laser tracker measurement coordinate system. sl Then, the laser tracker is used to measure the fixture target point to obtain the coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system bl , according to the coordinate transformation matrix T between the three-dimensional scanner measurement coordinate system and the laser tracker measurement coordinate system sl The coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system bl Calculate and obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system sb ; Step 3, installing the fixture on the tracker of the 3D scanner, installing the laser tracker and the 3D scanner, and installing the common target ball seat; Step 4: Use a 3D scanner to scan the target ball of the public measurement area mark point, and at the same time, use a laser tracker to measure the laser target ball on the scanner tracker fixture, replace the target ball of the public area mark point with the laser target ball, and use the laser tracker to measure the laser target ball; use the scanner to perform laser scanning measurement on the two areas of the product to be measured respectively; use the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system obtained in step 2 sb The coordinates of the two segments of point cloud data measured by the 3D scanner are processed, and the processed data are converted to the global coordinate system to achieve overall data splicing and complete the collaborative measurement of the laser tracker and the 3D scanner.

2. The laser tracker and 3D scanner collaborative measurement method according to claim 1, characterized in that: In the step one, a global measurement coordinate system is established using a laser tracker, the measurement coordinate system of the three-dimensional scanner is located on the scanner tracker, and the designed fixture is placed on the scanner tracker; at least four target ball seats are placed on the fixture, the distribution positions of the four target ball seats should not be collinear, and the angle of the triangle formed by every three target ball seats should not be greater than 120 degrees.

3. The laser tracker and 3D scanner collaborative measurement method according to claim 2, characterized in that: The step 2 specifically includes: Place at least 4 public target sphere seats on a smooth plane, and the public target sphere seats constitute a public target sphere seat coordinate system O t X t Y t Z t , ensuring that the placement position can be recognized by both the laser tracker and the 3D scanner; First, place a laser target ball that can be recognized by the laser tracker on the target ball seat to obtain the position of the target point. The laser tracker optical target point Q il ,il=1,2,...,nl(il≥4); Then replace the laser target ball with a special target ball with a marker that can be recognized by a 3D scanner. Use a 3D scanner to fit the center of each target ball and obtain the position of the target point. The laser scanner optical marker point Q is ,is=1,2,…,ns(is≥4); According to the optical target point Q il and the optical target point Q il The laser tracker measures the coordinate system O l X l Y l Z l The observed data P il Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl ; According to the laser scanner optical marker point Q is And laser scanner optical marker Q is Measuring coordinate system O in 3D scanner s X s Y s Z s The observed data R is Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The transformation matrix T between ts ; According to the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl With the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The transformation matrix T between ts Calculate and obtain the 3D scanner measurement coordinate system O s X s Y s Z s Measure coordinate system O with laser tracker l X l Y l Z l The coordinate transformation matrix T sl ; Use the laser tracker to measure the target in the fixture coordinate system. Set the optical target point Q on the target on the fixture. ib The laser tracker measures the coordinate system O l X l Y l Z l The observed data is P ib , according to the optical target point Q ib And the observation data P ib Calculate and obtain the fixture coordinate system O b X b Y b Z b Measure coordinate system O with laser tracker l X l Y l Z l The coordinate transformation matrix T between bl ; According to the coordinate transformation matrix T between the three-dimensional scanner measurement coordinate system and the laser tracker measurement coordinate system sl The coordinate transformation matrix T between the fixture coordinate system and the laser tracker measurement coordinate system bl Calculate and obtain the coordinate transformation matrix T between the 3D scanner measurement coordinate system and the fixture coordinate system sb .

4. The laser tracker and 3D scanner collaborative measurement method according to claim 3, characterized in that: According to the optical target point Q il and the optical target point Q il The laser tracker measures the coordinate system O l X l Y l Z l The observed data P il Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl Specifically include: According to P il =R tl Q il +M tl Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The rotation transformation matrix R tl And the translation matrix M tl ; According to the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The rotation transformation matrix R tl And the translation matrix M tl Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measure coordinate system O with laser tracker l X l Y l Z l The transformation matrix T between tl .

5. The laser tracker and 3D scanner collaborative measurement method according to claim 4, characterized in that: According to the laser scanner optical marker point Q is And laser scanner optical marker Q is Measuring coordinate system O in 3D scanner s X s Y s Z s The observed data R is Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The transformation matrix T between ts Specifically include: According to P is =R ts Q is +M ts Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The rotation transformation matrix R ts And the translation matrix M ts ; According to the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The rotation transformation matrix R ts And the translation matrix M ts Calculate and obtain the common target sphere coordinate system O t X t Y t Z t Measuring coordinate system O with 3D scanner s X s Y s Z s The transformation matrix T between ts .

6. The laser tracker and 3D scanner collaborative measurement method according to claim 5, characterized in that: The three-dimensional scanner measures the coordinate system O s X s Y s Z s Measure coordinate system O with laser tracker l X l Y l Z l The coordinate transformation matrix T sl According to T sl =T tl ×T ts -1 Calculate acquisition.

7. The laser tracker and 3D scanner collaborative measurement method according to claim 6, characterized in that: The coordinate transformation matrix T between the three-dimensional scanner measurement coordinate system and the fixture coordinate system sb According to T sb =T bl -1 ×T sl =T bl -1 ×T tl ×T ts -1 Calculate acquisition.

8. The laser tracker and 3D scanner collaborative measurement method according to any one of claims 1 to 7, characterized in that: The step three specifically includes: Install the fixture on the tracker of the 3D scanner and firmly connect the fixture to the tracker of the 3D scanner by tightening the bolts; Install laser trackers and 3D scanners; Install the public target ball mounts. The four public target ball mounts should be placed in the public measurement area, at a set distance from the two equipment hosts. The opening directions of the four laser target balls and the marking point target ball should be easily recognized by the laser tracker and 3D scanner.

9. The laser tracker and 3D scanner collaborative measurement method according to claim 8, characterized in that: The step 4 specifically includes: Use a 3D scanner to scan the target ball marking the public measurement area, and at the same time, use a laser tracker to measure the laser target ball on the scanner tracker fixture. Replace the target ball marking the public area with the laser target ball, and use the laser tracker to measure the laser target ball. The three sets of data are automatically imported into the calibration algorithm in the measurement software to realize the calibration of the measurement coordinate system of the 3D scanner and the fixture coordinate system, and then convert the measurement coordinate system of the scanner to the global coordinate system. Use a scanner to perform laser scanning and measurement on the two areas respectively. At the same time, the laser tracker tracks and measures the laser target ball on the scanner tracker fixture. After the scanning is completed, the measurement software automatically converts the coordinates of the two segments of point cloud data obtained by the scanner into the global coordinate system to achieve overall splicing.

10. A laser tracker and three-dimensional scanner collaborative measurement system, characterized in that: The laser tracker and three-dimensional scanner collaborative measurement system uses the laser tracker and three-dimensional scanner collaborative measurement method according to any one of claims 1 to 9 to perform collaborative testing.

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