Laser scanning path planning method and device for measuring sheet metal parts of a civil aircraft

Abstract

The application provides a laser scanning path planning method and device for measuring a sheet metal part of a civil aircraft, and the method comprises the following steps: acquiring discrete point cloud data of a structure numerical model of a sheet metal part to be measured, wherein the structure of the sheet metal part to be measured comprises a profile and an edge cut; acquiring a laser scanning path of the profile of the sheet metal part to be measured based on the discrete point cloud data of the structure numerical model of the sheet metal part to be measured; acquiring a laser scanning path of the edge cut of the sheet metal part to be measured based on the discrete point cloud data of the structure numerical model of the sheet metal part to be measured; and determining a laser scanning path of the sheet metal part to be measured based on the laser scanning path of the profile and the laser scanning path of the edge cut. The application can meet the detection requirements of different spatial profiles and edge cut features, expand the coverage range of the detection objects of the sheet metal part of the civil aircraft, and improve the flexibility and detection efficiency of the detection process.

Description

Technical Field

[0001] This invention relates to the field of digital measurement technology for mechanical parts, and in particular to a laser scanning path planning method and equipment for measuring sheet metal parts of civil aircraft. Background Technology

[0002] In the manufacturing process of civil aircraft, sheet metal parts account for a large proportion of the components and are a key focus of inspection. Compared with traditional manual inspection methods such as templates, calipers, and feeler gauges, using non-contact laser scanners combined with robotic inspection technology to obtain three-dimensional point cloud data can more accurately and completely present the actual shape and features of the parts in space, resulting in more comprehensive evaluation results. Therefore, this technology is increasingly being used in the inspection of sheet metal parts for civil aircraft.

[0003] However, civil aircraft sheet metal parts are characterized by a wide variety and small batches. Using robotic clamping and scanning equipment has always resulted in a large amount of manual teaching work and low measurement efficiency. Summary of the Invention

[0004] This invention provides a laser scanning path planning method and device for measuring sheet metal parts of civil aircraft. It automatically plans the laser scanning path of sheet metal parts, thereby solving the defects of large manual teaching workload and low measurement efficiency when using robot clamping scanning equipment in the prior art, and improving the automation and flexibility of the laser scanning process.

[0005] This invention provides a laser scanning path planning method for measuring sheet metal parts of civil aircraft, comprising:

[0006] The discrete point cloud data of the structural digital model of the sheet metal part to be tested is obtained, wherein the structure of the sheet metal part to be tested includes the profile and the cut edge;

[0007] Based on the discrete point cloud data of the structural digital model of the sheet metal part under test, the initial measurement point information of the surface of the sheet metal part under test is obtained. Based on the initial measurement point information of the surface, the critical path point information and the normal information of the surface are obtained. Based on the critical path point information and the normal information of the surface, the laser scanning path of the surface is obtained.

[0008] Based on the discrete point cloud data of the structural digital model of the sheet metal part under test, the measurement point information of the cut edge of the sheet metal part under test and the normal vector corresponding to the cut edge are obtained; based on the measurement point information of the cut edge and the normal vector corresponding to the cut edge, the laser scanning path of the cut edge is obtained.

[0009] The laser scanning path of the sheet metal part to be tested is determined based on the laser scanning path of the surface and the laser scanning path of the cut edge.

[0010] According to the laser scanning path planning method for measuring sheet metal parts of civil aircraft provided by the present invention, before acquiring the discrete point cloud data of the structural digital model of the sheet metal part to be measured, the method further includes:

[0011] Establish a aligning coordinate system, and align the structural digital model of the sheet metal part to be tested from its initial posture based on the aligning coordinate system.

[0012] According to the laser scanning path planning method for measuring sheet metal parts of civil aircraft provided by the present invention, before acquiring the discrete point cloud data of the structural digital model of the sheet metal part to be measured, the method further includes:

[0013] Establish a aligning coordinate system, and align the structural digital model of the sheet metal part to be tested from its initial posture based on the aligning coordinate system.

[0014] According to the present invention, a laser scanning path planning method for measuring sheet metal parts of civil aircraft is provided, wherein the profile of the sheet metal part to be measured includes multiple sub-profiles.

[0015] Based on the discrete point cloud data of the structural digital model of the sheet metal part under test, the initial measurement point information of the surface of the sheet metal part under test is obtained, including: constructing the bounding box of each sub-surface of the sheet metal part under test respectively, and simplifying the discrete point cloud data of the surface of the sheet metal part under test based on the bounding box of each sub-surface.

[0016] Based on the simplified discrete point cloud data of the surface of the sheet metal part to be tested, the surface of the sheet metal part to be tested is cut in a predetermined direction to obtain the cut surface of the surface.

[0017] Based on the cutting surface of the surface, discrete point cloud data within a preset distance of the cutting surface of the surface are obtained;

[0018] Distance offset is applied to the discrete point cloud data within the preset distance to obtain the initial measurement point information of the surface.

[0019] According to the present invention, a laser scanning path planning method for measuring sheet metal parts of civil aircraft includes constructing bounding boxes for each sub-surface of the sheet metal part to be measured, and simplifying the discrete point cloud data of the surface of the sheet metal part to be measured based on the bounding boxes of each sub-surface, comprising:

[0020] The discrete point cloud data of the multiple sub-surfaces are uniformly divided, and the minimum bounding box surrounding the discrete point cloud data of each sub-surface is constructed to obtain the center point data of each minimum bounding box.

[0021] The set of center point data of each minimum bounding box is used as the discrete point cloud data of the simplified surface of the sheet metal part under test.

[0022] According to the present invention, a laser scanning path planning method for measuring sheet metal parts of civil aircraft includes cutting the surface of the sheet metal part under test in a predetermined direction based on simplified discrete point cloud data of the surface of the sheet metal part under test to obtain a cut surface of the surface, comprising:

[0023] The structural digital model of the sheet metal part is cut along the X-axis, Y-axis and Z-axis directions according to a predetermined interval to obtain the cutting surfaces of the structural digital model of the sheet metal part in the X-axis, Y-axis and Z-axis directions.

[0024] Calculate the distance from the discrete point cloud data of the sheet metal part to be tested to each cutting surface, and filter out the discrete point cloud data within the preset distance;

[0025] The discrete point cloud data within the preset distance is offset by distance, and the offset discrete point cloud data is used as the initial measurement point data of the surface of the sheet metal part to be tested.

[0026] According to the present invention, a laser scanning path planning method for measuring sheet metal parts of civil aircraft includes obtaining critical path point information and normal information of the surface based on initial measurement point information of the surface, and obtaining the laser scanning path of the surface based on the critical path point information and normal information of the surface, comprising:

[0027] Project the initial measurement points of the acquired profile onto the corresponding cutting surface;

[0028] Determine the projection points of each cut surface that take the maximum and minimum values ​​in the X, Y, and Z directions respectively;

[0029] The projection points of each cut surface, taking the maximum and minimum values ​​in the X, Y, and Z directions, are used as the critical path points of the surface.

[0030] Based on the critical path points of the surface and the optimal scanning direction and optimal scanning distance of the preset laser scanning device, the measurement points of each cutting surface and the normal information of each cutting surface are obtained.

[0031] Based on the measuring points and normal information of each cutting surface, the laser scanning path of the surface is obtained.

[0032] According to the present invention, a laser scanning path planning method for measuring sheet metal parts of civil aircraft includes obtaining measurement point information of the cut edges of the sheet metal parts and the corresponding normal vectors of the cut edges based on discrete point cloud data of the structural digital model of the sheet metal parts to be measured, comprising:

[0033] Obtain the initial measurement point data of the cut edge of the sheet metal part to be tested;

[0034] Interpolation encryption is performed between adjacent points of the initial measurement point of the cut edge to obtain encrypted measurement point data of the cut edge. The encrypted measurement point data is then biased and rotated, and the encrypted measurement point data after biasing and rotating is used as the measurement point information of the cut edge.

[0035] Based on the encrypted measurement point data before and after rotation, the normal vector corresponding to the measurement point of the cut edge is obtained.

[0036] The initial measurement point data of the cut edge is subjected to interpolation and encryption processing. The initial measurement points of the cut edge after interpolation and encryption processing are then subjected to offset rotation to obtain the measurement point information of the cut edge and the normal vector corresponding to the measurement points of the cut edge.

[0037] According to the present invention, a laser scanning path planning method for measuring sheet metal parts of civil aircraft includes obtaining the initial measurement points of the cut edge of the sheet metal part to be measured, comprising:

[0038] Obtain the boundary point cloud data of the sheet metal part to be tested;

[0039] Based on the boundary point cloud data, the point cloud data of the cut edge of the sheet metal part to be tested is obtained using the convex hull algorithm, and the point cloud data of the cut edge of the sheet metal part to be tested is used as the initial measurement point data of the cut edge of the sheet metal part to be tested.

[0040] According to the present invention, a laser scanning path planning method for measuring sheet metal parts of civil aircraft includes interpolating and encrypting the initial measurement point data of the cut edge, and then offsetting and rotating the initial measurement points of the cut edge after interpolation and encryption to obtain the measurement point information of the cut edge and the corresponding normal vector of the measurement points of the cut edge, comprising:

[0041] Interpolation encryption is performed between adjacent points of the initial measurement point of the cut edge to obtain encrypted measurement point data of the cut edge. The encrypted measurement point data is then biased and rotated, and the encrypted measurement point data after biasing and rotating is used as the measurement point information of the cut edge.

[0042] Based on the encrypted measurement point data before and after rotation, the normal vector corresponding to the measurement point of the cut edge is obtained.

[0043] According to the present invention, a laser scanning path planning method for measuring sheet metal parts of civil aircraft determines the laser scanning path of the sheet metal part to be measured based on the laser scanning path of the profile and the laser scanning path of the cut edge, including:

[0044] The laser scanning paths of the surface and the cut edge are combined in a preset order to obtain the laser scanning path of the sheet metal part to be tested.

[0045] The present invention also provides a laser scanning path planning device for measuring sheet metal parts of civil aircraft, comprising:

[0046] The acquisition module is used to acquire discrete point cloud data of the structural digital model of the sheet metal part to be tested, wherein the structure of the sheet metal part to be tested includes the profile and the cut edge.

[0047] The surface path planning module is used to obtain the initial measurement point information of the surface of the sheet metal part under test based on the discrete point cloud data of the structural digital model of the sheet metal part under test; based on the initial measurement point information of the surface, obtain the critical path point information and the normal information of the surface; and based on the critical path point information and the normal information of the surface, obtain the laser scanning path of the surface.

[0048] The edge cutting path planning module is used to obtain the measurement point information of the edge of the sheet metal part under test and the corresponding normal vector of the edge based on the discrete point cloud data of the structural digital model of the sheet metal part under test; and to obtain the laser scanning path of the edge based on the measurement point information of the edge and the corresponding normal vector of the edge.

[0049] The determination module is used to determine the laser scanning path of the sheet metal part to be tested based on the laser scanning path of the surface and the laser scanning path of the cut edge.

[0050] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement any of the laser scanning path planning methods for measuring sheet metal parts of civil aircraft described above.

[0051] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the laser scanning path planning method for measuring sheet metal parts of civil aircraft as described above.

[0052] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the laser scanning path planning method for measuring sheet metal parts of civil aircraft as described above.

[0053] The laser scanning path planning method and equipment for measuring sheet metal parts of civil aircraft provided by this invention can automatically plan laser scanning paths according to the different shapes and cutting edge structures of sheet metal parts, meet the detection requirements of spatial shapes, cutting edges and other features, thereby improving the coverage of sheet metal parts to be inspected, and ultimately improving the flexibility and efficiency of the inspection process. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0055] Figure 1 This is a flowchart illustrating the laser scanning path planning method for measuring sheet metal parts of civil aircraft provided in an embodiment of the present invention.

[0056] Figure 2 This is a schematic diagram of the path planning process for civil aircraft sheet metal parts provided in another embodiment of the present invention;

[0057] Figure 3 This is a diagram showing the result of sheet metal surface feature path planning provided in an embodiment of the present invention;

[0058] Figure 4 This is a diagram showing the results of sheet metal trimming and surface feature path planning provided in an embodiment of the present invention.

[0059] Figure 5 A schematic diagram of the laser scanning path planning device for measuring sheet metal parts of civil aircraft provided by the present invention;

[0060] Figure 6 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0062] In the description of the invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] In practical applications, with the continuous development of the civil aircraft equipment manufacturing industry, the technical requirements for the inspection of civil aircraft parts are becoming increasingly stringent. Sheet metal parts, as a significant component in civil aircraft manufacturing, have always been a key focus of inspection. Compared to traditional manual inspection methods such as templates, calipers, and feeler gauges, the 3D point cloud data obtained by non-contact laser scanners combined with robotic inspection technology can more accurately and completely present the actual morphological characteristics of parts in space, resulting in more comprehensive evaluation results. Therefore, this technology is increasingly being applied to the inspection of sheet metal parts for civil aircraft. However, civil aircraft sheet metal parts are characterized by a wide variety and small batches. Using robotic clamping scanning equipment has always resulted in a large workload of manual teaching and low measurement efficiency. Therefore, how to automatically plan measurement paths based on the inspection characteristics of sheet metal parts, avoiding a large amount of manual teaching work, improving the automation and flexibility of the laser scanning process, covering more types of civil aircraft sheet metal parts, and ultimately improving inspection efficiency is currently a key focus and challenge in the inspection of civil aircraft sheet metal parts.

[0064] In existing scanning path planning technologies, traditional methods do not take into account the detection planning of the cutting edges of parts and a large number of spatial surface features, and are not suitable for civil aircraft sheet metal parts with many varieties and small batches, so the degree of flexibility is not high.

[0065] In view of the above problems, the present invention provides a laser scanning path planning method and device for measuring sheet metal parts of civil aircraft. The method plans the path based on key measurement points of the surface features of the sheet metal parts and the path planning based on the cutting edge features of the sheet metal parts, thereby planning the laser scanning path of the sheet metal parts to be tested. This method can not only plan the detection of sheet metal parts of civil aircraft, but also meet the detection requirements of features such as spatial surface and cutting edge, thereby improving the coverage of the detection objects of sheet metal parts of civil aircraft, and ultimately improving the flexibility and efficiency of the detection process.

[0066] Figure 1 This is a flowchart illustrating the laser scanning path planning method for measuring sheet metal parts of civil aircraft provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the method includes:

[0067] Step 101: Obtain discrete point cloud data of the structural digital model of the sheet metal part to be tested, wherein the structure of the sheet metal part to be tested includes the profile and the cut edge;

[0068] Step 102: Based on the discrete point cloud data of the structural digital model of the sheet metal part to be tested, obtain the initial measurement point information of the surface of the sheet metal part to be tested; based on the initial measurement point information of the surface, obtain the critical path point information and the normal information of the surface; based on the critical path point information and the normal information of the surface, obtain the laser scanning path of the surface.

[0069] Step 103: Based on the discrete point cloud data of the structural digital model of the sheet metal part to be tested, obtain the measurement point information of the cut edge of the sheet metal part to be tested and the normal vector corresponding to the cut edge; based on the measurement point information of the cut edge and the normal vector corresponding to the cut edge, obtain the laser scanning path of the cut edge.

[0070] Step 104: Determine the laser scanning path of the sheet metal part to be tested based on the laser scanning path of the surface and the laser scanning path of the cut edge.

[0071] The above steps will be explained in detail below with reference to specific embodiments.

[0072] Step 101: Obtain discrete point cloud data of the structural digital model of the sheet metal part to be tested, wherein the structure of the sheet metal part to be tested includes the profile and the cut edge;

[0073] It is worth noting that for the digital model file of the sheet metal part to be tested or other objects to be tested, firstly, the digital model file can be parsed by OpenCasCade (OCC) to generate discrete point cloud data; secondly, according to the structural characteristics of the civil aircraft sheet metal parts, they are divided into surface features and cutting edge features. Points are sampled for the surface features and cutting edge features respectively, and further measurement point generation, measurement point optimization, path planning and other steps are performed to generate the measurement path for the target part, which is then provided as input data to the robot for part scanning.

[0074] In this step, the sheet metal parts of civil aircraft can be divided into surface features and edge features according to their structure. The path planning technology for sheet metal parts of civil aircraft is first based on the open-source 3D model engine OCC, which discretizes the digital model parts into point cloud data, and establishes a calibrated coordinate system to provide a reference data basis for the part path planning technology.

[0075] Step 102: Based on the discrete point cloud data of the structural digital model of the sheet metal part to be tested, obtain the initial measurement point information of the surface of the sheet metal part to be tested; based on the initial measurement point information of the surface, obtain the critical path point information and the normal information of the surface; based on the critical path point information and the normal information of the surface, obtain the laser scanning path of the surface.

[0076] In this step, for path planning of the profile, a bounding box is constructed to simplify the part based on the part's reference point cloud data. Then, the part data is cut in both horizontal and vertical directions to construct multiple cutting planes. The nearest points from the point cloud to the cutting planes are queried, and then the maximum and minimum points in each direction are extracted, including x. min ,x max ,y max ,y min ,z min ,z maxThe key measurement point parameters are obtained, and finally, the "S"-shaped line cutting method is used to sort all the measurement points and offset them according to the measurement distance and normal vector, thus forming the measurement path of the part surface.

[0077] Specifically, the surface of the sheet metal part to be tested includes multiple sub-surfaces. First, the bounding boxes of each sub-surface of the sheet metal part to be tested are constructed respectively. Based on the bounding boxes of each sub-surface, the discrete point cloud data of the surface of the sheet metal part to be tested is simplified.

[0078] In other words, the discrete point cloud data of the multiple sub-surfaces are uniformly divided to construct the minimum bounding box that surrounds the discrete point cloud data of each sub-surface, and the center point data of each minimum bounding box is obtained; the set of the center point data of each minimum bounding box is used as the simplified discrete point cloud data of the surface of the sheet metal part to be tested.

[0079] Furthermore, based on the simplified discrete point cloud data of the surface of the sheet metal part to be tested, the surface of the sheet metal part to be tested is cut in a predetermined direction to obtain the cutting surface of the surface; based on the cutting surface of the surface, discrete point cloud data within a preset distance of the cutting surface of the surface is obtained; the discrete point cloud data within the preset distance is offset to obtain the initial measurement point information of the surface.

[0080] Specifically, the structural digital model of the sheet metal part is cut along the X-axis, Y-axis, and Z-axis directions at predetermined intervals to obtain the cutting surfaces of the structural digital model of the sheet metal part in the X-axis, Y-axis, and Z-axis directions; the distance from the discrete point cloud data of the sheet metal part to be tested to each cutting surface is calculated, and discrete point cloud data within a preset distance are selected; the discrete point cloud data within the preset distance is offset, and the offset discrete point cloud data is used as the initial measurement point data of the surface of the sheet metal part to be tested.

[0081] Furthermore, based on the initial measurement point information of the surface, the critical path point information and the normal information of the surface are obtained. Based on the critical path point information and the normal information of the surface, the laser scanning path of the surface is obtained.

[0082] Specifically, the initial measurement points of the acquired surface are projected onto the respective cutting surfaces; the projection points on each cutting surface that take the maximum and minimum values ​​in the X, Y, and Z directions are determined; the projection points on each cutting surface that take the maximum and minimum values ​​in the X, Y, and Z directions are used as the critical path points of the surface; based on the critical path points of the surface and the optimal scanning direction and optimal scanning distance of the preset laser scanning device, the measurement points and normal information of each cutting surface are obtained; based on the measurement points and normal information of each cutting surface, the laser scanning path of the surface is obtained.

[0083] Step 103: Based on the discrete point cloud data of the structural digital model of the sheet metal part to be tested, obtain the measurement point information of the cut edge of the sheet metal part to be tested and the normal vector corresponding to the cut edge; based on the measurement point information of the cut edge and the normal vector corresponding to the cut edge, obtain the laser scanning path of the cut edge.

[0084] In this step, to obtain the measurement point information of the cut edge of the sheet metal part to be tested and the corresponding normal vector of the cut edge, it is first necessary to obtain the initial measurement point data of the cut edge of the sheet metal part to be tested.

[0085] Specifically, the boundary point cloud data of the sheet metal part to be tested is acquired; based on the boundary point cloud data, the point cloud data of the cut edge of the sheet metal part to be tested is obtained using the convex hull algorithm, and the point cloud data of the cut edge of the sheet metal part to be tested is used as the initial measurement point data of the cut edge of the sheet metal part to be tested.

[0086] Furthermore, interpolation encryption is performed between adjacent points of the initial measurement point of the tangent edge to obtain encrypted measurement point data of the tangent edge. The encrypted measurement point data is then biased and rotated, and the biased and rotated encrypted measurement point data is used as the measurement point information of the tangent edge. Based on the encrypted measurement point data before and after rotation, the normal vector corresponding to the measurement point of the tangent edge is obtained.

[0087] For example, for path planning of edge features, the point cloud data of the boundary in the projection plane of the sheet metal part can be extracted first by using the convex hull algorithm. Then, the boundary points can be reordered using the ant colony algorithm, and the sampling points can be biased using the Rodrigue formula, thereby completing the path planning algorithm for edge features.

[0088] Step 104: Determine the laser scanning path of the sheet metal part to be tested based on the laser scanning path of the surface and the laser scanning path of the cut edge.

[0089] In this step, the laser scanning paths of the sheet metal surface and the cutting edge obtained through the above steps are combined in a preset order to obtain the laser scanning path of the sheet metal part to be tested.

[0090] In one specific embodiment, the sheet metal parts of civil aircraft include surface features and edge features. The path planning technology for civil aircraft sheet metal parts first utilizes the open-source 3D modeling engine OCC to discretize the digital model parts into point cloud data. A coordinate system is established to provide a reference data foundation for the part path planning technology. Secondly, for surface path planning, based on the part's reference point cloud data, a bounding box is constructed for simplification. Then, the part data is cut in both horizontal and vertical directions to construct multiple cutting planes. The nearest points from the point cloud to the cutting planes are found, and then the maximum and minimum points in each direction are extracted, including x... min ,x max ,y max,y min ,z min ,z max Finally, an "S"-shaped row cutting method is used to sort all measurement points and offset them according to the measurement distance and normal vector, thus forming the measurement path of the part surface. For the key technology of path planning for edge features, the point cloud data of the boundary in the projection surface of the sheet metal part is first extracted by the convex hull algorithm, the boundary points are reordered by the ant colony algorithm, and then the Rodrigues formula is used to offset the sampling points, thereby completing the path planning algorithm for edge features.

[0091] Figure 2 This is a schematic diagram of the path planning process for civil aircraft sheet metal parts provided in another embodiment of the present invention, as shown below. Figure 2 As shown, the path planning for civil aircraft sheet metal parts can be broken down into the following steps:

[0092] Step 210: The civil aircraft sheet metal parts are discretized using UV sampling via OpenCasCad (OCC) to obtain the digital model point cloud data {P} of the sheet metal parts. i}, and the model is aligned from any spatial orientation using a coordinate system establishment method;

[0093] Step 220: Construct a bounding box (Box) for the part model, and calculate the length, width, and height parameters (x) of the bounding box. min ,y min ,z min ,x max ,y max ,z max Since sheet metal parts typically generate large amounts of point cloud data, which can impact subsequent analysis efficiency, a minimum bounding box is constructed by uniformly dividing the reference point cloud data in all directions. Finally, the center point of each sub-bounding box is retained to complete the simplification process, and this is denoted as {P}. i '}.

[0094] Step 221: Cut the part model along the X-axis and Y-axis directions respectively, where the cutting surface can be obtained by formula (1).

[0095] x=S(i) (1)

[0096] Step 222: For the generation of path points for the surface, this embodiment mainly uses the "S" line cutting method of the processing path to obtain them, by setting multiple cutting planes S. i The distance equation from spatial point P(a,b,c) to plane Ax+By+Cz=D is obtained through formula (2):

[0097]

[0098] Optionally, by setting a threshold, point cloud information within dis < 50mm can be retained, and a distance offset can be applied to obtain the measurement point information of the surface, and then traversing {P i The distances from all points to the dividing plane are calculated, and points within a certain distance threshold are projected onto each plane. Specifically, the point (x0, y0, z0) is projected onto the projection point (x0, y0, z0) of the dividing plane. T ,y T ,z T The equation is (3):

[0099]

[0100] Step 223: In this step, in the Y direction, take the points corresponding to the maximum (Y) and minimum (Y) of the projection points on each cross-section; in the X direction, take the points corresponding to the maximum (X) and minimum (X) of the projection points on each cross-section; and in the Z direction, take the points corresponding to the maximum (Z) and minimum (Z) of the projection points on each cross-section. And according to S... i Sort Y in ascending and descending order based on the parity of i. Generally, sort Y in ascending order when i is odd and in descending order when i is even. Then collect data from each interface S. i Using the first and last coordinates on the surface, combined with the maximum and minimum values ​​in each direction of the aforementioned cross-section, the key measuring points (x, y, y) are extracted using a zigzag pattern, similar to slicing a cake. i ,y min / y max ,z min / z max ).

[0101] Figure 3 This is a diagram showing the result of sheet metal surface feature path planning provided in an embodiment of the present invention, such as... Figure 3 As shown, in this embodiment of the invention, the key path point information of the surface is constructed based on the line cutting method, and the optimal scanning direction and optimal scanning distance of the scanning head are integrated to form the measurement points and their normal information of each surface, thereby completing the scanning path planning of the surface.

[0102] Step 230: When the sheet metal part has a truncated edge feature, project the part point cloud data obtained in step 2 onto the XOY plane of the aligned coordinate system to obtain the boundary point cloud data. Then, use the Graham algorithm to construct the convex hull of the model. The specific steps are as follows:

[0103] Step 1: Select the point P0 with the smallest ordinate as the first point of the convex hull, and translate the flat point cloud according to the position of P0, and set it as the new origin P0';

[0104] Step 2: Calculate the polar angle θ from each of the remaining points to the new P0' point. iArrange them in ascending order counterclockwise, and find the first point P1 and the last point P after sorting by polar angle. n ;

[0105] Step 3: Based on the stack principle, determine whether the subsequently obtained point is within P. i ' -1 The positional relationship between P and the straight line formed by the stack vertices, if P i If a point is to the left of the line, it is considered a point on the convex hull; if a point is to the right of the line, it is removed. This process continues until all points have been traversed. The final list of points on the convex hull is then stored in {P}. con}, forming the cutting edge point.

[0106] Step 231, because the point {P} on the convex hull con The problem of insufficient data exists. Therefore, interpolation is performed between adjacent points to encrypt the data, and the ant colony algorithm is used for reordering. The ant colony algorithm sorting process is as follows:

[0107] Step 1: Initialize the population size M = 20, the problem dimension D = 2, and the cutting edge points {P}. con The maximum number of iterations is T = 500, the pheromone factor is α = 1, the importance is β = 5, and the initial pheromone content τ of path (i,j) is... ij (t) = Q, τ at the beginning time ij (0) = 0;

[0108] Step 2: The ant colony traverses each input edge measurement point P. con,k After each individual ant in the colony has traversed all the measurement points, it completes path selection and updates the taboo table. The taboo table contains the positions ants have traversed at each time step, where the probability of the k-th ant being between point i and j is given. Its formula is shown in (4), and the ant with the shortest total distance Min(dis) is found as the global optimal solution;

[0109]

[0110] Step 3: Update the global pheromone concentration using the classic ant update model, as shown in formula (5):

[0111]

[0112] Step 4: Iterate and update until the maximum number of iterations is met, and output the path point information of the ant with the shortest path.

[0113] Step 232, introduce Rodriguez's formula, and set point P′ con According to the adjacent point P' con,i-1 The normal of the straight line formed is taken as the normal of the rotation axis L(n)x ,n y ,n z For each point, after a scan distance of offset d, the tangent path point P is obtained after rotation ω. q For formula (6):

[0114] p′=cos(ω)·p+(1-cos(ω))(L·p)·L+sin(ω)·(L×p) (6)

[0115] Step 233: Calculate the difference between the points before and after rotation to obtain the normal vector F of the tangent point, thereby obtaining the tangent path (P) formed by the tangent edge position point and its normal vector. q ,F).

[0116] Step 240: Combine the laser scanning paths of the sheet metal surface and the cutting edge obtained through the above steps in a preset order to obtain the laser scanning path of the sheet metal part to be tested.

[0117] Figure 4 The following is a diagram showing the results of sheet metal trimming and surface feature path planning provided in an embodiment of the present invention: Figure 4 As shown, this method can adaptively generate path point information based on the shape of the sheet metal part.

[0118] For example, as part of one embodiment, after obtaining the laser scanning path of the surface of the sheet metal part to be tested and the laser scanning path of the cutting edge, the laser scanning of the surface of the sheet metal part to be tested can be performed first, and then the laser scanning of the cutting edge can be performed, according to the specific task requirements and equipment characteristics, that is, the combination can be performed in the order of surface first and then cutting edge; or, the laser scanning of the cutting edge of the sheet metal part to be tested can be performed first, and then the laser scanning of the surface can be performed, that is, the combination can be performed in the order of cutting edge first and then surface; or, according to the principle of proximity, the scanning order can be preset, and the laser scanning paths of the surface and cutting edge of the sheet metal part to be tested can be combined in sequence.

[0119] It is worth noting that, due to the state of the three-dimensional component in three-dimensional space, the accessibility and collision analysis of the measurement point data generated by the above-mentioned three-dimensional component path planning technology is carried out. Specifically, based on the position of the robot's base coordinate system and combined with the measurement point information, the nearest point is found through the measurement point and the digital model point cloud of the part, and collision and accessibility analysis are performed respectively.

[0120] Figure 5 This is a schematic diagram of the laser scanning path planning device for measuring sheet metal parts of civil aircraft provided by the present invention. The following is in conjunction with... Figure 5The laser scanning path planning device for measuring sheet metal parts of civil aircraft provided by this invention is described below. The laser scanning path planning device for measuring sheet metal parts of civil aircraft described below can be referred to in correspondence with the laser scanning path planning method for measuring sheet metal parts of civil aircraft provided by this invention described above. For example... Figure 5 As shown, the device includes:

[0121] The acquisition module 51 is used to acquire discrete point cloud data of the structural digital model of the sheet metal part to be tested, wherein the structure of the sheet metal part to be tested includes the profile and the cut edge;

[0122] The surface path planning module 52 is used to obtain the initial measurement point information of the surface of the sheet metal part under test based on the discrete point cloud data of the structural digital model of the sheet metal part under test; based on the initial measurement point information of the surface, obtain the critical path point information and the normal information of the surface; and based on the critical path point information and the normal information of the surface, obtain the laser scanning path of the surface.

[0123] The cutting edge path planning module 53 is used to obtain the measurement point information of the cutting edge of the sheet metal part under test and the corresponding normal vector of the cutting edge based on the discrete point cloud data of the structural digital model of the sheet metal part under test; and to obtain the laser scanning path of the cutting edge based on the measurement point information of the cutting edge and the corresponding normal vector of the cutting edge.

[0124] The determination module 54 is used to determine the laser scanning path of the sheet metal part to be tested based on the laser scanning path of the surface and the laser scanning path of the cut edge.

[0125] The laser scanning path planning device for measuring sheet metal parts of civil aircraft in this embodiment of the invention acquires discrete point cloud data of the structural digital model of the sheet metal part to be measured through an acquisition module. The structure of the sheet metal part to be measured includes a profile and a cut edge. Based on the discrete point cloud data of the structural digital model of the sheet metal part to be measured, the profile path planning module acquires the initial measurement point information of the profile of the sheet metal part to be measured. Based on the initial measurement point information of the profile, the critical path point information and the normal information of the profile are obtained. Based on the critical path point information and the normal information of the profile, the device further acquires the initial measurement point information and the normal information of the profile. The laser scanning path of the surface is obtained; the edge cutting path planning module obtains the measurement point information of the edge cutting of the sheet metal part under test and the corresponding normal vector of the edge cutting based on the discrete point cloud data of the structural digital model of the sheet metal part under test; the laser scanning path of the edge cutting is obtained based on the measurement point information of the edge cutting and the corresponding normal vector of the edge cutting; the laser scanning path of the edge cutting is determined by the determination module based on the laser scanning path of the surface cutting and the laser scanning path of the edge cutting. The present invention can adaptively generate a laser scanning path according to the surface cutting and edge cutting of the sheet metal part.

[0126] Figure 6This is a schematic diagram of the structure of the electronic device provided by the present invention, such as... Figure 6 As shown, the electronic device may include: a processor 610, a communication interface 620, a memory 630, and a communication bus 640, wherein the processor 610, the communication interface 620, and the memory 630 communicate with each other through the communication bus 640. The processor 610 can call logic instructions in the memory 630 to execute a laser scanning path planning method for measuring sheet metal parts of civil aircraft. The method includes: acquiring discrete point cloud data of a structural digital model of the sheet metal part to be measured, wherein the structure of the sheet metal part includes a profile and a cut edge; based on the discrete point cloud data of the structural digital model of the sheet metal part to be measured, acquiring initial measurement point information of the profile of the sheet metal part to be measured; based on the initial measurement point information of the profile, obtaining critical path point information and normal information of the profile; based on the critical path point information and normal information of the profile, obtaining a laser scanning path for the profile; based on the discrete point cloud data of the structural digital model of the sheet metal part to be measured, acquiring measurement point information of the cut edge of the sheet metal part to be measured and the corresponding normal vector of the cut edge; based on the measurement point information and the corresponding normal vector of the cut edge, obtaining a laser scanning path for the cut edge; and based on the laser scanning path of the profile and the laser scanning path of the cut edge, determining a laser scanning path for the sheet metal part to be measured.

[0127] Furthermore, the logical instructions in the aforementioned memory 630 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0128] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the laser scanning path planning method for measuring sheet metal parts of civil aircraft provided by the above methods. The method includes: acquiring discrete point cloud data of the structural digital model of the sheet metal part to be measured, wherein the structure of the sheet metal part to be measured includes a profile and a cut edge; based on the discrete point cloud data of the structural digital model of the sheet metal part to be measured, acquiring initial measurement point information of the profile of the sheet metal part to be measured; and based on the... The initial measurement point information of the profile is used to obtain the critical path point information and normal information of the profile; based on the critical path point information and normal information of the profile, the laser scanning path of the profile is obtained; based on the discrete point cloud data of the structural digital model of the sheet metal part under test, the measurement point information of the cut edge of the sheet metal part under test and the normal vector of the cut edge are obtained; based on the measurement point information and normal vector of the cut edge, the laser scanning path of the cut edge is obtained; based on the laser scanning path of the profile and the laser scanning path of the cut edge, the laser scanning path of the sheet metal part under test is determined.

[0129] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements a laser scanning path planning method for measuring sheet metal parts of civil aircraft provided by the methods described above. This method includes: acquiring discrete point cloud data of a structural digital model of a sheet metal part to be measured, wherein the structure of the sheet metal part includes a profile and cut edges; based on the discrete point cloud data of the structural digital model of the sheet metal part to be measured, acquiring initial measurement point information of the profile of the sheet metal part to be measured; and based on the initial measurement point information of the profile, obtaining the... The key path point information and normal information of the surface are obtained; based on the key path point information and normal information of the surface, the laser scanning path of the surface is obtained; based on the discrete point cloud data of the structural digital model of the sheet metal part under test, the measurement point information of the cut edge of the sheet metal part under test and the corresponding normal vector of the cut edge are obtained; based on the measurement point information and the corresponding normal vector of the cut edge, the laser scanning path of the cut edge is obtained; based on the laser scanning path of the surface and the laser scanning path of the cut edge, the laser scanning path of the sheet metal part under test is determined.

[0130] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0131] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser scanning path planning method for measuring sheet metal parts of civil aircraft, characterized in that, include: The discrete point cloud data of the structural digital model of the sheet metal part to be tested is obtained, wherein the structure of the sheet metal part to be tested includes the profile and the cut edge; Based on the discrete point cloud data of the structural digital model of the sheet metal part under test, the initial measurement point information of the surface of the sheet metal part under test is obtained, specifically including: The structural digital model of the sheet metal part is cut along the X-axis, Y-axis and Z-axis directions according to a predetermined interval to obtain the cutting surfaces of the structural digital model of the sheet metal part in the X-axis, Y-axis and Z-axis directions. Calculate the distance from the discrete point cloud data of the sheet metal part to be tested to each cutting surface, and filter out the discrete point cloud data within the preset distance; The discrete point cloud data within the preset distance is offset by distance, and the offset discrete point cloud data is used as the initial measurement point data of the surface of the sheet metal part to be tested. Based on the initial measurement point information of the surface, the critical path point information and the normal information of the surface are obtained; based on the critical path point information and the normal information of the surface, the laser scanning path of the surface is obtained, specifically including: Project the initial measurement points of the acquired profile onto the corresponding cutting surface; Determine the projection points of each cut surface that take the maximum and minimum values ​​in the X, Y, and Z directions respectively; The projection points of each cut surface, taking the maximum and minimum values ​​in the X, Y, and Z directions, are used as the critical path points of the surface. Based on the critical path points of the surface and the optimal scanning direction and optimal scanning distance of the preset laser scanning device, the measurement points of each cutting surface and the normal information of each cutting surface are obtained. Based on the measurement points and normal information of each cutting surface, the laser scanning path of the surface is obtained. Based on the discrete point cloud data of the structural digital model of the sheet metal part under test, the measurement point information of the cut edge of the sheet metal part under test and the normal vector corresponding to the cut edge are obtained; based on the measurement point information of the cut edge and the normal vector corresponding to the cut edge, the laser scanning path of the cut edge is obtained. The laser scanning path of the sheet metal part to be tested is determined based on the laser scanning path of the surface and the laser scanning path of the cut edge.

2. The laser scanning path planning method for measuring sheet metal parts of civil aircraft according to claim 1, characterized in that, Before acquiring the discrete point cloud data of the structural digital model of the sheet metal part to be tested, the following steps are also included: Establish a aligning coordinate system, and align the structural digital model of the sheet metal part to be tested from its initial posture based on the aligning coordinate system.

3. The laser scanning path planning method for measuring sheet metal parts of civil aircraft according to claim 1, characterized in that, The profile of the sheet metal part to be tested includes multiple sub-profiles. Before cutting the structural digital model of the sheet metal part, the method further includes: Construct bounding boxes for each sub-surface of the sheet metal part under test, and simplify the discrete point cloud data of the surface of the sheet metal part under test based on the bounding boxes of each sub-surface. Based on the simplified discrete point cloud data of the surface of the sheet metal part to be tested, the surface of the sheet metal part to be tested is cut in a predetermined direction to obtain the cut surface of the surface.

4. The laser scanning path planning method for measuring sheet metal parts of civil aircraft according to claim 3, characterized in that, The process of constructing bounding boxes for each sub-surface of the sheet metal part under test, and simplifying the discrete point cloud data of the surface of the sheet metal part under test based on the bounding boxes of each sub-surface, includes: The discrete point cloud data of the multiple sub-surfaces are uniformly divided, and the minimum bounding box surrounding the discrete point cloud data of each sub-surface is constructed to obtain the center point data of each minimum bounding box. The set of center point data of each minimum bounding box is used as the discrete point cloud data of the simplified surface of the sheet metal part under test.

5. The laser scanning path planning method for measuring sheet metal parts of civil aircraft according to claim 2, characterized in that, The discrete point cloud data based on the structural digital model of the sheet metal part under test is used to obtain the measurement point information of the cut edge of the sheet metal part under test and the corresponding normal vector of the cut edge, including: Obtain the initial measurement point data of the cut edge of the sheet metal part to be tested; The initial measurement point data of the cut edge is subjected to interpolation and encryption processing. The initial measurement points of the cut edge after interpolation and encryption processing are then subjected to offset rotation to obtain the measurement point information of the cut edge and the normal vector corresponding to the measurement points of the cut edge.

6. The laser scanning path planning method for measuring sheet metal parts of civil aircraft according to claim 5, characterized in that, The process of obtaining the initial measurement points for the cut edge of the sheet metal part to be tested includes: Obtain the boundary point cloud data of the sheet metal part to be tested; Based on the boundary point cloud data, the point cloud data of the cut edge of the sheet metal part to be tested is obtained using the convex hull algorithm, and the point cloud data of the cut edge of the sheet metal part to be tested is used as the initial measurement point data of the cut edge of the sheet metal part to be tested.

7. The laser scanning path planning method for measuring sheet metal parts of civil aircraft according to claim 5, characterized in that, The process of interpolating and encrypting the initial measurement point data of the cut edge, and then performing an offset rotation on the initial measurement points of the interpolated and encrypted cut edge to obtain the measurement point information of the cut edge and the corresponding normal vector of the measurement points of the cut edge, includes: Interpolation encryption is performed between adjacent points of the initial measurement point of the tangent edge to obtain encrypted measurement point data of the tangent edge. The encrypted measurement point data is then biased and rotated, and the biased and rotated encrypted measurement point data is used as the measurement point information of the tangent edge. Based on the encrypted measurement point data before and after rotation, the normal vector corresponding to the measurement point of the cut edge is obtained.

8. The laser scanning path planning method for measuring sheet metal parts of civil aircraft according to any one of claims 1-7, characterized in that, Based on the laser scanning path of the surface and the laser scanning path of the cut edge, the laser scanning path of the sheet metal part to be tested is determined, including: The laser scanning paths of the surface and the cut edge are combined in a preset order to obtain the laser scanning path of the sheet metal part to be tested.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the laser scanning path planning method for measuring sheet metal parts of civil aircraft as described in any one of claims 1 to 8.

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