An automobile part paint spraying path optimization method and system based on data processing

Abstract

The application relates to the technical field of data processing, in particular to a car part paint spraying path optimization method and system based on data processing. The method comprises the following steps: acquiring an initial three-dimensional surface model of a paint spraying surface of a car part; processing triangular meshes in a local range in the initial three-dimensional surface model according to the difference of normal vectors of the triangular meshes to obtain a target three-dimensional surface model; determining all key paint spraying points needed to be passed through in paint spraying from the target three-dimensional surface model, and determining the value of substitution between two key paint spraying points in paint spraying; taking the sum of the values of substitution of adjacent key paint spraying points in the paint spraying path as a target function, and determining a target paint spraying path by minimizing the target function, so that the paint spraying surface is painted along the target paint spraying path. Through the above technical scheme, the efficiency of paint spraying on the car part can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data processing, and particularly relates to a vehicle part paint spraying path optimization method and system based on data processing. BACKGROUND

[0002] Vehicle part paint spraying is an indispensable link in vehicle manufacturing. Paint spraying can form a protective film on the surface of the part to prevent the part from rusting or corroding due to long-term exposure to the air, thereby prolonging the service life of the vehicle part. By spraying paint on the vehicle part, the durability of the vehicle part can be improved, and the surface of the painted part has higher wear resistance and ultraviolet resistance, which can better resist the erosion of the external environment, thereby maintaining the performance and appearance of the vehicle part.

[0003] Currently, a spray gun can be arranged at the end of a mechanical arm. The spray gun moves flexibly under the driving of the mechanical arm, thereby changing the position of the spray gun and the paint spraying angle of the paint spraying position relative to the vehicle part. When the position of the spray gun reaches a predetermined position and the angle between the spray gun and the vehicle part reaches a predetermined angle, paint spraying can be performed by controlling the spray gun to realize paint spraying on the vehicle part.

[0004] In related technologies, the mechanical arm can move according to a preset program, a preset trajectory and a speed. The spray gun maintains a certain distance (for example, 15-30 cm) from the surface of the workpiece to be painted during the movement of the mechanical arm, thereby ensuring the paint spraying effect on the surface of the vehicle part.

[0005] In the process of using the spray gun to paint the vehicle part, the movement trajectory of the spray gun may not be determined in combination with the actual situation of the vehicle part. In order to ensure the paint spraying effect on the vehicle part, the movement length required by the spray gun is relatively long, or the number of invalid rotations of the spray gun is relatively large, thereby affecting the efficiency of paint spraying on the vehicle part. SUMMARY

[0006] To improve the efficiency of paint spraying on the vehicle part, the present application provides a vehicle part paint spraying path optimization method and system based on data processing.

[0007] According to a first aspect of the embodiments of the present application, a data processing-based automobile part paint spraying path optimization method is provided, including: obtaining an initial three-dimensional surface model of a paint-spraying surface of an automobile part, the initial three-dimensional surface model being obtained by constructing a triangular mesh according to three-dimensional point cloud data of the paint-spraying surface; determining whether to perform a merging processing on the triangular meshes in a local range according to a difference in normal vectors of the triangular meshes in the local range, to obtain a target three-dimensional surface model processed from the initial three-dimensional surface model; determining all key paint spraying points required to be passed through during paint spraying from the target three-dimensional surface model, determining a cost value of paint spraying between two key paint spraying points according to a distance between the two key paint spraying points, a required angle change amount of paint spraying, and curvatures at the two key paint spraying points; taking a sum of the cost values of adjacent key paint spraying points in a paint spraying path as a target function, and determining a target paint spraying path by minimizing the target function, to perform paint spraying on the paint-spraying surface along the target paint spraying path.

[0008] In this way, the invalid moving time of the spray gun during paint spraying can be reduced, and thus the paint spraying efficiency of the automobile part can be improved.

[0009] Optionally, the determining whether to perform the merging processing on the triangular meshes in the local range according to the difference in the normal vectors of the triangular meshes in the local range includes: determining a representative vector of the normal vectors of the triangular meshes in the local range, and determining a paint spraying difficulty value of the local range according to a difference in directions between the normal vectors of the triangular meshes in the local range and the representative vector; and in a case where the paint spraying difficulty values of two adjacent local ranges are both less than a preset paint spraying difficulty threshold, determining to perform the merging processing on the triangular meshes of the two adjacent local ranges.

[0010] Optionally, the performing the merging processing on the triangular meshes of the two adjacent local ranges includes: determining a new position point of two adjacent triangular meshes in a total local range composed of the two local ranges according to an average value of the normal vectors of the triangular meshes in the total local range; connecting the new position point to boundaries of the two adjacent triangular meshes respectively, to obtain a merging processing result of the two adjacent triangular meshes, and to complete the merging processing on all un-merged two adjacent triangular meshes in the total local range.

[0011] In this way, the sub-regions of the total local range after the merging processing on the triangular meshes can be smoother, the paint spraying processing on the total local range can be facilitated, the number of times or the angle of rotation of the spray gun can be reduced, and the service life of the rotating part of the mechanical arm can be improved.

[0012] Optionally, the value of the paint spraying between the two key paint spraying points is determined by determining a first ratio between an angle change amount required when the two key paint spraying points are painted and a maximum angle change amount, and determining a first sum of the first ratio and a first preset positive number; determining a maximum curvature in the normalized curvatures at the two key paint spraying points respectively, and determining a second sum of the maximum curvature and a second preset positive number; multiplying the normalized distance between the two key paint spraying points, the first sum and the second sum to obtain the value of the paint spraying between the two key paint spraying points.

[0013] In this way, the normalized distance between the two key paint spraying points and the complexity of the surface can be comprehensively considered, and the paint spraying path of the automobile part can be conveniently planned.

[0014] Optionally, the method of determining all the key paint spraying points required to be passed through when painting the target three-dimensional surface model comprises: determining a target interval for selecting the key paint spraying points from a local range according to the curvatures of the vertices in the local range in the target three-dimensional surface model, so as to select the key paint spraying points from the local range according to the target interval; and the target interval is positively correlated with the average value of the curvatures of all the vertices of the triangular mesh in the local range.

[0015] Optionally, the target paint spraying path is determined by minimizing the target function, and the method comprises: searching for the paint spraying path by using a target optimization algorithm with the aim of minimizing the target function, and taking the paint spraying path obtained when the search process converges as the target paint spraying path; and the target optimization algorithm is any one of a genetic algorithm, an ant colony algorithm, a simulated annealing algorithm and a particle swarm optimization algorithm.

[0016] In this way, the paint spraying path can be searched, and a relatively accurate target paint spraying path can be obtained.

[0017] Optionally, the method of painting the surface to be painted along the target paint spraying path comprises: painting the surface to be painted along the target paint spraying path, and painting the target position points according to the curvature information of the target position points in the target three-dimensional surface model in the target paint spraying path at a travel speed inversely proportional to the curvature information.

[0018] Optionally, the method further comprises: determining an included angle between the travel directions of a previous position point and a next position point of the target paint spraying path, and performing multiple spline interpolation processing on a sub-path between the adjacent position points in a case where the included angle is greater than a preset angle threshold, so as to take the path obtained after the multiple spline interpolation processing on the sub-path as the target paint spraying path again.

[0019] In this way, the shaking caused by the sharp turn of the mechanical arm during movement can be avoided, thereby improving the service life of the mechanical arm driving the spray gun to move.

[0020] Optionally, the method further comprises: obtaining a historical spray path of a same model of a painted surface that has passed the inspection, and a historical three-dimensional surface model of the same model of the painted surface; matching the target three-dimensional surface model and the historical three-dimensional surface model, adjusting the historical spray path according to the difference information obtained by the matching to obtain a candidate spray path, and storing the correspondence between the target three-dimensional surface model and the candidate spray path.

[0021] In this way, the correspondence between the target three-dimensional surface model and the candidate spray path can be stored, which facilitates the direct calling of the matched spray path in the subsequent painting process, thereby improving the painting efficiency of the automobile parts.

[0022] According to a second aspect of the embodiments of the present application, a data processing-based automobile part spray path optimization system is provided, comprising: a processor and a memory, the memory storing computer program instructions, and the computer program instructions are executed by the processor to implement the steps of the data processing-based automobile part spray path optimization method provided in the first aspect of the present application.

[0023] The technical scheme provided by the embodiments of the present application can have the following beneficial effects: obtaining an initial three-dimensional surface model of a to-be-painted surface of an automobile part, and determining whether to perform a merging processing on the triangular meshes in a local range according to the difference of the normal vectors of the triangular meshes in the local range in the initial three-dimensional surface model to obtain a target three-dimensional surface model; the target three-dimensional surface model helps to reduce the number of adjustments of the moving direction or the number of rotations of the spray gun during the painting process of the mechanical arm; taking the sum of the generation values of the adjacent key spray points in the spray path as a target function, and determining a target spray path by minimizing the target function, the obtained target spray path can achieve the global optimization of the painting process, and painting the to-be-painted surface along the target spray path can reduce the invalid moving time of the spray gun during the painting process, thereby improving the painting efficiency of the automobile parts.

[0024] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a flowchart of a data processing-based automobile part spray path optimization method according to an exemplary embodiment;

[0026] Figure 2is a structural schematic diagram of a data processing-based automobile part paint spraying path optimization system according to an exemplary embodiment. DETAILED DESCRIPTION

[0027] To improve the paint spraying efficiency of automobile parts during paint spraying, an embodiment of the present application provides a data processing-based automobile part paint spraying path optimization method and system, Figure 1 is a flowchart of a data processing-based automobile part paint spraying path optimization method according to an exemplary embodiment, as shown in Figure 1 The method includes the following steps.

[0028] In step S101, an initial three-dimensional surface model of a paint-spraying surface of an automobile part is obtained.

[0029] The initial three-dimensional surface model is obtained by constructing a triangular mesh according to three-dimensional point cloud data of the paint-spraying surface.

[0030] The three-dimensional laser scanner can be used to pre-scan the paint-spraying surface of the automobile part in all directions, and obtain three-dimensional point cloud data of the paint-spraying surface, which includes three-dimensional coordinates of different position points of the paint-spraying surface of the automobile part.

[0031] According to the obtained point cloud data, the point cloud data can be processed by using algorithms such as Delaunay triangulation and Poisson surface reconstruction algorithm, to obtain an initial three-dimensional surface model composed of triangular meshes.

[0032] The density of the triangular mesh can be determined according to the actual situation such as the coverage radius of the spray gun. For example, to improve the accuracy of the triangular mesh, a higher density can be used to construct the initial three-dimensional surface model; or in the case of a relatively flat surface of the automobile part, a lower density can be used to construct the initial three-dimensional surface model.

[0033] The process of constructing the three-dimensional surface model can be performed by a terminal with stronger computing power such as a server, and after the execution is completed, the obtained three-dimensional surface model is sent to a terminal device used to control the paint spraying process of the automobile part.

[0034] By obtaining the initial three-dimensional surface model of the paint-spraying surface of the automobile part, the actual situation of the paint-spraying surface of the automobile part can be understood, so as to determine a matching paint spraying path for the paint-spraying surface according to the actual situation of the paint-spraying surface of the automobile part; the automobile part can be a vehicle part such as a vehicle frame or a vehicle door that needs to be painted.

[0035] In step S102, whether to perform the merging processing on the triangular meshes in the local range according to the difference of the normal vectors of the triangular meshes in the local range in the initial three-dimensional surface model is determined to obtain a target three-dimensional surface model processed from the initial three-dimensional surface model.

[0036] The normal vector of the triangular mesh can reflect the direction of the triangular mesh. For the same local range in the initial three-dimensional surface model, if the plurality of triangular meshes in the local range are similar in the normal vector, it indicates that the directions of the plurality of triangular meshes in the local range are consistent, and the plurality of triangular meshes in the local range are relatively flat.

[0037] On the contrary, for the same local range in the initial three-dimensional surface model, if the plurality of triangular meshes in the local range are different in the normal vector, it indicates that the plurality of triangular meshes in the local range are different in the direction, and the shape of the plurality of triangular meshes in the local range can be relatively complex. The local range can correspond to a relatively complex region of the surface of the automobile part, for example, the handle region of the door.

[0038] In order to ensure the processing accuracy of the relatively complex region of the surface of the automobile part and reduce the processing difficulty of the relatively flat region of the surface of the automobile part, whether to perform the merging processing on the triangular meshes in the local range can be determined according to the difference of the normal vectors of the triangular meshes in the local range in the initial three-dimensional surface model.

[0039] In one embodiment, whether to perform the merging processing on the triangular meshes in the local range according to the difference of the normal vectors of the triangular meshes in the local range in the initial three-dimensional surface model includes: determining a representative vector of the normal vectors of the triangular meshes in the local range, determining a painting difficulty value of the local range according to the difference of the normal vectors of the triangular meshes in the local range and the representative vector in the direction, and determining to perform the merging processing on the triangular meshes of the two adjacent local ranges when the painting difficulty values of the two adjacent local ranges are less than a preset painting difficulty threshold.

[0040] The painting difficulty value of the local range can be determined according to the difference of the normal vectors of the triangular meshes in the local range and the representative vector in the direction, which can realize the quantification of the painting difficulty of the local range. The higher the painting difficulty value of the local region is, the more complex the surface of the local region is, and the higher the painting difficulty of the local region is, which can require more complex painting trajectories or more changes in the painting angle.

[0041] On the contrary, the lower the painting difficulty value of the local region is, the simpler the surface of the local region is, and the lower the painting difficulty of the local region is. When the local region is painted, the same painting angle can be used to effectively paint the entire local region.

[0042] In the case that the paint difficulty values of the two adjacent local ranges are both less than the preset paint difficulty threshold, it is indicated that the paint difficulties of the two adjacent local ranges are both small, and the two adjacent local ranges can both be relatively flat, and the paint spraying of the two local ranges can be effectively realized through less adjustment times of the paint spraying angle.

[0043] In the case that the paint difficulty values of the two adjacent local ranges are both less than the preset paint difficulty threshold, it is determined to perform the merging processing on the triangular meshes of the two adjacent local ranges, which can realize the screening of the triangular mesh regions that need to be processed, and facilitate the subsequent planning of the paint spraying path of the adjacent local ranges, so as to reduce the number of changes of the paint spraying angle in the paint spraying process.

[0044] The preset paint difficulty threshold can be set according to actual needs. In the case that the paint difficulty value is processed by normalization, the value of the preset paint difficulty threshold can be between 0.3 and 0.4.

[0045] In the case that the paint difficulty value of at least one of the two adjacent local ranges is greater than or equal to the preset paint difficulty threshold, it can be determined to retain the triangular meshes of the two adjacent local ranges in the original direction without performing the merging processing on the triangular meshes of the two adjacent local ranges, so as to take into account the paint spraying effect of the relatively complex and relatively flat regions of the surface to be painted of the automobile part.

[0046] For the relatively complex region of the surface to be painted of the automobile part, the shape of the relatively complex region can be completely retained, so as to ensure the paint spraying effect of the relatively complex region of the surface to be painted. For the relatively flat region of the surface to be painted of the automobile part, the adjustment times of the paint spraying angle in the paint spraying process can be reduced, the service life of the rotating structure of the mechanical arm can be improved, and the time required for the paint spraying of the relatively flat region can be shortened, so as to improve the paint spraying efficiency of the automobile part.

[0047] In one embodiment, the merging processing on the triangular meshes of the two adjacent local ranges comprises: determining a new position point of the two adjacent triangular meshes in a total local range composed of the two local ranges according to the average value of the normal vectors of the triangular meshes in the total local range; connecting the new position point with the boundaries of the two adjacent triangular meshes respectively to obtain the merging processing result of the two adjacent triangular meshes, so as to complete the merging processing of all unmerged two adjacent triangular meshes in the total local range.

[0048] The two local ranges to be combined and processed can be two adjacent local ranges similar in the direction of the average vector, so as to spray paint the relatively flat area of the surface of the automobile part.

[0049] For example, in the total local range composed of the two local ranges, there can be multiple triangular meshes with the same direction; or, there can be some triangular meshes with different directions in the total local range, but the directions of the triangular meshes with different directions are similar, so that the spraying of the triangular meshes in the total local range can be realized by the same spraying direction or a relatively smooth spraying path.

[0050] According to the average value of the normal vectors of the triangular meshes in the total local range, the new position point of the two adjacent triangular meshes can be determined, which can include: determining a target normal vector where the average value of the normal vectors of the triangular meshes in the total local range is located; determining a target plane perpendicular to the target normal vector, the target plane passing through two vertices of the two adjacent triangular meshes except the end points of the common edge; determining the new position point according to the common edge of the two adjacent triangular meshes and the target plane; and the shortest distance from the new position point to the target plane is equal to the shortest distance from the new position point to the common edge of the two adjacent triangular meshes.

[0051] For example, for the two adjacent triangular meshes in the total local range, there can be vertices P1, P2, P3 and P4, wherein P2 and P3 are two end points of the common edge of the two adjacent triangular meshes, and P1 and P4 are located in different triangular meshes of the two adjacent triangular meshes; P1, P2 and P3 are located in one of the two adjacent triangular meshes, and P2, P3 and P4 are located in the other of the two adjacent triangular meshes.

[0052] The target normal vector where the average value of the normal vectors of the triangular meshes in the total local range is located can be determined, and a target plane perpendicular to the target normal vector is determined, the target plane passing through the vertices P1 and P4, and the new position point P5 can be determined according to the common edge of the two adjacent triangular meshes and the target plane; and the shortest distance from the new position point P5 to the target plane is equal to the shortest distance from the new position point P5 to the common edge of the two adjacent triangular meshes.

[0053] If the line segment between the vertex P1 and P4 is L1, the line segment between P2 and P3 is L2, and the new position point P5 is between the line segment L1 and the line segment L2; the position point P5 can be connected with P1, P2, P3 and P4 in turn, so as to form a plurality of triangular meshes after the merging processing, and the triangular meshes after the merging processing are smoother than the triangular meshes before the merging processing, and the difference between the triangular meshes before the merging processing and the triangular meshes after the merging processing is smaller.

[0054] Further, the merging process is determined according to the average of the normal vectors of the triangular meshes in the total local range, and after the merging processing of the triangular meshes not subjected to the merging processing in the total local range is completed, the overall direction of the total local range after the merging processing of the triangular meshes is consistent with the original overall direction, and the sub-regions of the total local range are smoother, so that the total local range is facilitated to be subjected to the paint spraying processing.

[0055] After the merging processing of the triangular meshes not subjected to the merging processing is completed, the total local range is obtained, and when the robot arm drives the spray gun to spray paint on the surface of the total local range, the robot arm can perform smoother operation and ensure the paint spraying effect on the total local range.

[0056] For example, the number of times or the angle of rotation of the spray gun can be reduced, the service life of the rotating part of the robot arm is improved, and the invalid motion of the robot arm during the paint spraying process is avoided, and the paint spraying efficiency on the total local range is improved.

[0057] In step S103, all key paint spraying points required to be passed through during the paint spraying are determined from the target three-dimensional surface model, and the cost value of the paint spraying between two key paint spraying points is determined according to the distance between the two key paint spraying points, the angle change required for the paint spraying, and the curvatures at the two key paint spraying points.

[0058] The spray gun has a corresponding coverage diameter when performing the paint spraying operation, and the spray gun performing the paint spraying operation sprays paint on all key paint spraying points of the surface of the automobile part to be sprayed, so that the paint spraying on the entire surface to be sprayed is completed. Therefore, all key paint spraying points required to be passed through during the paint spraying can be determined from the target three-dimensional surface model, so as to determine a more matched paint spraying path for the surface to be sprayed.

[0059] In one embodiment, all key paint spraying points required to be passed through during the paint spraying are determined from the target three-dimensional surface model, including: determining a target interval for selecting the key paint spraying points from a local range according to the curvatures of the vertices of the local range in the target three-dimensional surface model, so as to select the key paint spraying points from the local range according to the target interval; and the target interval is positively correlated with the average of the curvatures of all vertices of the triangular meshes in the local range.

[0060] The curvature of the vertex of the triangular mesh in the local range can reflect the sharpness of the triangular mesh in the local range, and can also reflect the amplitude of the transformation required for the spray angle when spraying the local range. In order to better achieve the spraying of the region with high complexity, and to improve the spraying efficiency of the region with low complexity, the selection strategy of the key point can be adaptively determined according to the actual situation of different regions.

[0061] In the case that the average value of the curvature of all vertices of the triangular mesh in the local range is greater than the preset curvature threshold, the selection of the key spray point from the local range can be performed according to the first preset interval; in the case that the average value of the curvature of all vertices of the triangular mesh in the local range is less than or equal to the preset curvature threshold, the selection of the key spray point from the local range can be performed according to the second preset interval; the first preset interval is smaller than the second preset interval.

[0062] Wherein, in the case that the curvature is normalized, the preset curvature threshold can be between 0.4 and 0.6.

[0063] The second preset interval can be determined according to the maximum coverage diameter of the spray gun, so as to fully utilize the spraying capacity of the spray gun and achieve the spraying of the relatively flat region of the surface to be sprayed of the automobile part; in order to ensure the spraying effect of the region where the key spray point is located and avoid excessive spraying, the spray gun can be controlled to adopt a matching coverage diameter for spraying operation according to the distance between the current key spray point and the adjacent other spray points, so as to ensure the uniformity of the spraying thickness of all positions of the surface to be sprayed.

[0064] The higher the curvature of all vertices of the triangular mesh in the local range, the more complex the surface condition of the local range, and the smaller interval for selecting the key spray point can ensure the spraying effect of the region with more complex condition.

[0065] The lower the curvature of all vertices of the triangular mesh in the local range, the flatter the surface of the local range, and the larger interval for selecting the key spray point can improve the spraying efficiency of the flatter region, and can reduce the number of rotations of the rotating parts of the mechanical arm, thereby improving the service life of the mechanical arm.

[0066] Wherein, the first preset interval and the second preset interval can be set according to the actual demand of the surface to be sprayed; for example, the first preset interval can be equal to 2 cm, and the second preset interval can be equal to 5 cm; those skilled in the art can also use more intervals of interval radius to select the key spray point, which will not be described here.

[0067] In one embodiment, the value of the replacement of the painting between the two key painting points is determined by the following manner: determining a first ratio between the angle change amount required when painting the two key painting points and the maximum angle change amount, and determining a first sum of the first ratio and a first preset positive number; determining the maximum curvature in the normalized curvatures at the two key painting points respectively, and determining a second sum of the maximum curvature and a second preset positive number; multiplying the normalized distance between the two key painting points, the first sum and the second sum to obtain the value of the replacement of the painting between the two key painting points.

[0068] The first ratio of the angle change amount and the maximum angle change amount can reflect the angle flexibility requirement of the mechanical arm when moving between two points; the angle change amount required when painting the two key painting points can be determined according to the normal vector of at least one triangular grid where the two position points are located; the greater the angle change amount required when painting the two key painting points, the greater the rotation mechanism of the mechanical arm needs to control the rotation of the spray gun when moving from painting one key painting point to painting another key painting point.

[0069] Determining the first sum of the first ratio and the first preset positive number can ensure that the first sum is at least greater than 0, avoiding effective participation in the subsequent multiplication operation; the first preset positive number can be 0.01 and 0.02 and other positive numbers.

[0070] The maximum curvature in the normalized curvatures at the two key painting points respectively can be the maximum one in the normalized curvatures at the two key painting points; using the maximum one in the curvatures of the two key painting points to determine the replacement value can better match the key painting points with more complex surfaces when at least one key painting point has a larger curvature.

[0071] In the case that the key painting point is the vertex of the triangular grid, the curvature of the key painting point can be determined according to the difference degree of the normal vectors of the three triangular grids with the key painting point as the vertex; the greater the difference degree of the normal vectors of the three triangular grids with the key painting point as the vertex, the greater the curvature of the key painting point.

[0072] Alternatively, in the case that the key painting point is not the vertex of the triangular grid, the curvature of the key painting point can be determined according to the difference degree of the normal vectors of the triangular grid where the key painting point is located and the adjacent other triangular grids; the greater the difference degree of the normal vectors of the triangular grid where the key painting point is located and the adjacent other triangular grids, the greater the curvature of the key painting point.

[0073] The second sum of the maximum curvature and the second preset positive number can be greater than or equal to 0, and can effectively participate in the subsequent multiplication operation; the second preset positive number can be 0.01 or 0.02.

[0074] The normalization process of the curvature of the key paint points can be implemented by minimum-maximum standardization, logarithmic transformation, arctangent function, Sigmoid function, etc.

[0075] The greater the distance between the two key paint points after normalization, the more likely the robot arm will move between the two key paint points again to cover other key paint points between the two key paint points after painting the two key paint points, and the more likely the robot arm will have invalid movement distance. Therefore, the greater the distance between the two key paint points after normalization, the greater the penalty value can be set.

[0076] The distance between the two key paint points after normalization, the first sum and the second sum are multiplied to obtain the penalty value for painting between the two key paint points, which can comprehensively consider the distance between the two key paint points after normalization and the curvature information of the two key paint points, so as to plan the painting path of the automobile part.

[0077] The following is an example of a calculation formula to illustrate the calculation process of the penalty value in the embodiment of the application: , wherein, is the penalty value for painting between the two key paint points, is the distance between the two key paint points after normalization, is the first preset positive number, is the angle change amount required when painting the two key paint points, is the second preset positive number, and max is the maximum value, and are the curvatures of the two key paint points, respectively.

[0078] The angle change amount required when painting the two key paint points is in the range of 0 to 180 degrees, which can realize the normalization of the angle change amount required when painting the two key paint points.

[0079] In step S104, the sum of the penalty values of the adjacent key paint points in the painting path is taken as the objective function, and the target painting path is determined by minimizing the objective function, so as to paint the surface to be painted along the target painting path.

[0080] In order to realize complete painting on the surface to be painted, the mechanical arm needs to pass through all the key painting points at least when driving the spray gun to paint the surface to be painted. Therefore, the sum of the values of the adjacent key painting points in the painting path can be used as the target function. When the target function reaches the minimum value, the difficulty or cost of painting the surface to be painted is minimized, the painting efficiency of the surface to be painted is improved, and the service life of the rotating part of the mechanical arm is at least improved by reducing the rotation angle required by the mechanical arm during painting.

[0081] In one embodiment, the target painting path is determined by minimizing the target function, including: searching the painting path by using a target optimization algorithm to minimize the target function, and obtaining the painting path when the search process converges as the target painting path; wherein the target optimization algorithm is any one of a genetic algorithm, an ant colony algorithm, a simulated annealing algorithm and a particle swarm optimization algorithm.

[0082] For example, the search of the painting path can be realized by using the target optimization algorithm, and the painting path passes through all the key painting points at least. When the number of searches reaches a pre-set number of times or the search time is greater than a pre-set specified time length, the painting path that makes the target function reach the minimum value in the search process can be used as the target painting path.

[0083] The search of the painting path by using the target optimization algorithm can obtain a relatively accurate target painting path and avoid local optimal solution of the painting path.

[0084] In one embodiment, the surface to be painted is painted along the target painting path, including: painting the surface to be painted along the target painting path, and painting the target position point according to the travel speed inversely proportional to the curvature information of the target position point in the target three-dimensional surface model according to the curvature information of the target position point in the target three-dimensional surface model.

[0085] When painting the surface to be painted, the number of steering operations required by the mechanical arm for the spray gun is less for the flat area of the surface to be painted, and a higher travel speed can be used for painting to improve the painting efficiency of the flat area.

[0086] When painting the surface to be painted, the number of steering operations required by the mechanical arm for the spray gun is more for the relatively sharp or complex area of the surface to be painted. In order to ensure the painting quality of the relatively sharp or complex area of the surface to be painted, a lower travel speed can be used for painting.

[0087] When painting the to-be-painted surface along the target painting path, the painting flow of the spray gun can be adaptively controlled, so that the painting amount of the spray gun to different regions of the to-be-painted surface is consistent, and insufficient painting or excessive painting of the to-be-painted surface is avoided.

[0088] In an embodiment, an included angle between a driving direction of a previous position point of the target painting path and a driving direction of a next position point of the target painting path can also be determined, and in a case where the included angle is greater than a preset angle threshold, the sub-path between the adjacent position points is subjected to multiple times of spline interpolation processing, so as to take the path obtained after the sub-path is subjected to multiple times of spline interpolation processing as the target painting path again.

[0089] The preset angle threshold can be between 90 degrees and 120 degrees, and in a case where the included angle is greater than the preset angle threshold, the sub-path between the adjacent position points is subjected to multiple times of spline interpolation processing, so that a more smooth trajectory can be obtained, the difficulty of rotation or movement of the mechanical arm driving the spray gun is reduced, sudden turns that can exist in the movement of the mechanical arm are avoided, the service life of the mechanical arm is improved, and the coverage of the painting process is more continuous, so that a better painting effect is obtained.

[0090] In an embodiment, a historical painting path of a painted surface of the same model and of the same type as the to-be-painted surface and a historical three-dimensional surface model of the painted surface of the same model and of the same type can also be obtained, the target three-dimensional surface model and the historical three-dimensional surface model are matched, the historical painting path is adjusted according to difference information obtained through the matching to obtain a candidate painting path, and a correspondence between the target three-dimensional surface model and the candidate painting path is stored.

[0091] For the surfaces of automobile parts of the same model, there can be certain differences in some regions due to errors that can exist in the production process, or there can be customized needs of users for automobile parts of the same model, so that there are certain subtle differences between different automobile parts of the same model.

[0092] The automobile part on which the embodiment of the present application performs painting is at least a qualified automobile part, therefore, different automobile parts of the same model at least have the same shape in most regions (for example, 80%), therefore, the target three-dimensional surface model and the historical three-dimensional surface model can be matched, and since the painting result of the historical three-dimensional surface model is qualified, the historical painting path can be better used to provide a reference for the current painting process.

[0093] The target three-dimensional surface model and the historical three-dimensional surface model are matched, the candidate paint spraying path is obtained by adjusting the historical paint spraying path according to the difference information obtained by matching, and the paint spraying path that matches the target three-dimensional surface model can be obtained by only adjusting the part with the difference, without re-executing the planning process of the paint spraying path, so that the accuracy of the obtained paint spraying path is ensured, and the efficiency of obtaining the paint spraying path is improved.

[0094] The corresponding relationship between the target three-dimensional surface model and the candidate paint spraying path is stored, the candidate paint spraying path can be called from the pre-stored corresponding relationship when the same type of automobile part is painted in the future, and the efficiency of painting the automobile part is improved.

[0095] In an embodiment, before painting the surface to be painted along the target paint spraying path, a virtual mechanical arm can be used to control a virtual paint gun to simulate painting the virtual surface corresponding to the target three-dimensional surface model along the target paint spraying path, and collision detection is performed on the simulated painting process; the target paint spraying path is adjusted according to the collision detection result to avoid contact between the outside of the virtual mechanical arm and the surface to be painted; and the obtained paint spraying path after adjustment is used as the target paint spraying path again.

[0096] The actual size of the mechanical arm can be used to construct the virtual mechanical arm, and the virtual surface can be constructed according to the target surface three-dimensional model, so that the virtual surface corresponding to the target three-dimensional surface model is simulated painted, the painting action can be pre-rehearsed in a simulated environment to avoid collision that may occur in the actual painting process, and the cost of painting is reduced.

[0097] In order to avoid the mechanical arm being contaminated by paint in the painting environment, a wrapping cloth made of nylon or other materials can be wrapped around the outside of the mechanical arm, and the size of the virtual mechanical arm can be set in combination with the size of the wrapping cloth to avoid the outside of the wrapping cloth touching the painted area of the surface to be painted in the subsequent actual painting process.

[0098] Adjusting the target paint spraying path according to the collision detection result can increase the distance of the path segment with collision to the surface to be painted, and adjusting the pressure of the paint gun for painting can keep the pressure of the paint falling on the surface to be painted consistent.

[0099] Using the obtained paint spraying path after adjustment as the target paint spraying path again can avoid the mechanical arm touching the surface to be painted of the automobile part during the movement process in the actual painting process, which affects the painting effect, and can improve the painting quality of the surface to be painted of the automobile part.

[0100] Figure 2is a structural schematic diagram of a data processing based automobile part paint spraying path optimization system 1000 according to an exemplary embodiment. Referring to Figure 2 The data processing based automobile part paint spraying path optimization system 1000 comprises a processor 1100 and a memory 1200, the memory 1200 stores computer program instructions, the computer program instructions are executed by the processor 1100 to realize all steps or part of steps of the data processing based automobile part paint spraying path optimization method in the present application.

[0101] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the application being indicated by the following claims.

[0102] It should be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application.

Claims

1. A method for optimizing the painting path of automotive parts based on data processing, characterized in that, include: The initial three-dimensional surface model of the automotive part to be painted is obtained. The initial three-dimensional surface model is obtained by constructing a triangular mesh based on the three-dimensional point cloud data of the surface to be painted. Based on the differences in the normal vectors of triangular meshes within a local area of ​​the initial 3D surface model, it is determined whether to merge the triangular meshes within the local area. This includes: determining a representative vector of the normal vectors of the triangular meshes within the local area; determining the painting difficulty value of the local area based on the degree of difference in direction between the normal vectors of the triangular meshes within the local area and the representative vector; and determining to merge the triangular meshes of the two adjacent local areas if the painting difficulty values ​​of two adjacent local areas are both less than a preset painting difficulty threshold, so as to obtain the target 3D surface model after processing the initial 3D surface model. The process of merging two adjacent local triangular meshes includes: for two adjacent triangular meshes in the total local area formed by the two local areas, determining the new position point of the two adjacent triangular meshes based on the average value of the normal vector of the triangular meshes in the total local area; connecting the new position point to the boundary of the two adjacent triangular meshes respectively, and obtaining the merging result of the two adjacent triangular meshes, so as to complete the merging process of all unmerged two adjacent triangular meshes in the total local area; Identify all key painting points that the paint needs to pass through from the target 3D surface model, including: Based on the curvature of vertices in a local area of ​​the target 3D surface model, a target interval is determined for selecting key paint points within that local area. The target interval is positively correlated with the average curvature of all vertices of the triangular mesh within the local area. The cost of painting between two key paint points is determined by the following method: a first ratio is determined between the required angle change for painting the two key paint points and the maximum angle change; a first sum of the first ratio and a first preset positive number is determined; the maximum curvature among the normalized curvatures at each of the two key paint points is determined; and a second sum of the maximum curvature and a second preset positive number is determined. Multiply the normalized distance between two key paint spraying points, the first sum, and the second sum to obtain the cost of spraying between the two key paint spraying points. The sum of the costs of adjacent critical paint points in the paint path is used as the objective function, and the target paint path is determined with the goal of minimizing the objective function, so that the surface to be painted is painted along the target paint path.

2. The method for optimizing the painting path of automotive parts based on data processing according to claim 1, characterized in that, Determining the target paint path with the objective function minimization as the goal includes: With the objective function minimization as the goal, an objective optimization algorithm is used to search for the paint spraying path, and the paint spraying path obtained when the search process converges is taken as the target paint spraying path. The objective optimization algorithm can be any one of the following: genetic algorithm, ant colony algorithm, simulated annealing algorithm, and particle swarm optimization algorithm.

3. The method for optimizing the painting path of automotive parts based on data processing according to claim 1, characterized in that, Painting the surface to be painted along the target painting path includes: Paint the surface to be painted along the target painting path, and paint the target position point according to the curvature information of the target position point in the target three-dimensional surface model, according to the driving speed that is inversely proportional to the curvature information.

4. The method for optimizing the painting path of automotive parts based on data processing according to claim 1, characterized in that, The method further includes: Determine the angle between the driving direction of the previous position point and the driving direction of the next position point of the target painting path. If the angle is greater than a preset angle threshold, perform multiple spline interpolation processes on the sub-paths between adjacent position points, so that the path obtained after multiple spline interpolation processes on the sub-paths can be used as the target painting path again.

5. The method for optimizing the painting path of automotive parts based on data processing according to claim 1, characterized in that, The method further includes: Obtain the historical paint path of the same model of painted surface that has passed the paint test, as well as the historical three-dimensional surface model of the same model of painted surface. The target 3D surface model and historical 3D surface models are matched. Based on the difference information obtained from the matching, the historical paint paths are adjusted to obtain candidate paint paths. The correspondence between the target 3D surface model and the candidate paint paths is stored.

6. A data processing-based automotive parts painting path optimization system, characterized in that, include: A processor and a memory, the memory storing computer program instructions that, when executed by the processor, implement the data processing-based automotive parts painting path optimization method according to any one of claims 1-5.

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