An Automatic Generation Method and Device for Free-Form Surface Spraying Path

Abstract

The present invention relates to a method and device for automatically generating a free-form surface spraying path. The method includes: extracting a feature surface according to the free-form surface point cloud data, and determining an index space according to the feature surface and the free-form surface point cloud data; segmenting the original polygon on the feature surface by using the method of sub-polygon division to obtain a plurality of sub-polygon line segment sets, the sum of the areas enclosed by the sub-polygon line segment sets is equal to the sum of the areas of the original polygon, and the sub-polygon line segment sets are connected end to end in sequence to obtain a sub-polygon; performing sub-polygon trajectory planning based on the sub-polygon to obtain a sub-polygon trajectory, obtaining spraying point indexes based on the sub-polygon trajectory and the index space, calculating spraying points and spraying postures according to the spraying point indexes, obtaining a spraying pose path based on the spraying points and spraying postures, and evaluating and outputting the spraying pose path. Compared with the prior art, the present invention has the advantages of being applicable to any free-form surface point cloud data, adjustable spraying width, etc.

Description

Technical Field

[0001] The present invention relates to the field of robot trajectory planning and automatic spraying, and particularly to a method and device for automatically generating a spraying path for a free-form surface. Background Art

[0002] Multi-axis robots are often used in the spraying of complex components. According to the trajectory programming method, robot spraying applications can be divided into manual teaching and offline programming. The spraying trajectory of a robot obtained by manual teaching has the characteristic of high reliability. However, relying on the operator's experience, the best spraying effect is usually not achieved. The offline programming method can generate a specific spraying trajectory according to the digital model and process parameters of the workpiece to be sprayed, and at the same time complete simulation verification, which is conducive to realizing automatic spraying.

[0003] Currently, most free-form surface spraying path planning processes the CAD model, performs surface cutting and slicing, calculates the geometric features of the cells, obtains path points, and generates a spraying trajectory. For example, a tool path planning method in the spraying forming process triangulates the standard CAD model to obtain the surface spraying trajectory of the workpiece. This method has only been tested on the inner cover of an automobile and is usually applicable to the case of a known standard CAD model, which is not conducive to the efficient generation of a spraying path for arbitrary free-form surface point cloud data, has a narrow scope of application, and cannot adjust the spraying width for spraying in different situations. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and device for automatically generating a free-form surface spraying path applicable to arbitrary free-form surface point cloud data and with adjustable spraying width, which overcomes the defects of the above-mentioned existing technologies.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A method for automatically generating a free-form surface spraying path includes the following steps:

[0007] Extract the feature surface according to the free-form surface point cloud data, and determine the index space according to the feature surface and the free-form surface point cloud data;

[0008] Use the method of sub-polygon division to segment the original polygon on the feature surface to obtain a plurality of sub-polygon line segment sets. The sum of the areas enclosed by the sub-polygon line segment sets is equal to the sum of the areas of the original polygon, and the sub-polygon line segment sets are connected end to end in sequence to obtain a sub-polygon;

[0009] Perform sub-polygon trajectory planning based on the sub-polygon to obtain a sub-polygon trajectory, obtain spray point indices based on the sub-polygon trajectory and the index space, calculate spray points and spray postures according to the spray point indices, obtain a spray pose path based on the spray points and spray postures, and evaluate and output the spray pose path;

[0010] Among them, the process of trajectory planning is as follows:

[0011] Set an offset line segment, which is outside the sub-polygon and does not intersect the sub-polygon;

[0012] Perform parallel line division on the sub-polygon and the offset line segment based on the spray width to obtain a set of parallel lines. Each parallel line in the set of parallel lines is parallel to each other, has 2 intersection points with the sub-polygon, and has 1 intersection point with the offset line segment. The index of the intersection point of each parallel line in the set of parallel lines with the offset line segment is the arrangement serial number of the parallel line;

[0013] Judge whether there are inflection points on the sub-polygon. If there are, draw a perpendicular line from the inflection point to the parallel line closest to the inflection point to obtain an inflection point extension line and the intersection point of the parallel line and the inflection point extension line;

[0014] Based on the arrangement serial number of the parallel lines, group the intersection points of the parallel lines and the sub-polygon and the intersection points of the parallel lines and the inflection point extension lines to obtain an intersection point set corresponding to each parallel line,

[0015] Screen the intersection point set corresponding to each parallel line to obtain a path point set corresponding to each parallel line;

[0016] After obtaining the path point set, connect the path points in the path point set according to the zigzag path algorithm to obtain a sub-polygon trajectory.

[0017] Furthermore, the specific expression for segmenting the original polygon on the feature surface by using the sub-polygon division method is:

[0018] polygon i =divide(polygon feat ),i∈1,...,n

[0019]

[0020] Among them, polygon i is the sub-polygon obtained by division, i is the serial number of the sub-polygon obtained by division, divide is the division function, polygon feat is the original polygon on the feature surface, n is the total number of sub-polygons obtained by division, and aera is the function for calculating the envelope area of the polygon.

[0021] Further, the constraint conditions for setting the offset line segment are as follows:

[0022]

[0023] where i is the serial number of the sub-polygon obtained by division, is the offset line segment, and polygon i is the i-th sub-polygon obtained by division, d lploy is the distance from the offset line segment to the sub-polygon, and δ is the minimum offset distance from the offset line segment to the sub-polygon.

[0024] Further, the constraint conditions for the feature plane are as follows:

[0025] Plane feat (x, y, z) = 0: A feat x + B feat y + C feat z + D feat = 0

[0026] Plane feat (x p , y p , z p ) > 0

[0027] Plane feat (x np , y np , z np ) < 0

[0028] n z · Plane feat (x, y, z) = 0

[0029] Plane feat (x L , y L , z L ) = 0

[0030] F L = (n x , n y , n z ) = PCA( B P)

[0031] where Plane feat is the plane function, x, y, and z are points on the feature plane, A feat , B feat , C feat and D feat are plane coefficients, x p , y p and z p are points in the point cloud region, xnp , y np and z np are points in the non-point cloud region, F L is the local coordinate system of the point cloud data, x L , y L and z L are points in the local coordinate system, n x , n y and n z are the three coordinate axis vectors of the local coordinate system, PCA is the PAC algorithm function, B P is the free-form surface point cloud.

[0032] Furthermore, the constraint condition for screening the intersection point set corresponding to each parallel line is:

[0033]

[0034]

[0035] where j is the arrangement serial number of the parallel lines, p j is the intersection point corresponding to the j-th parallel line, is the function for calculating the intersection points of the parallel line and the sub-polygon, is the j-th parallel line in the set of parallel lines, polygon i is the i-th sub-polygon obtained by division, l first is for polygon i 's main direction line.

[0036] Furthermore, the calculation formula for connecting the path points in the path point set according to the zigzag path algorithm is:

[0037] feat P dep = zizg(∑p j )

[0038] where, feat P dep is the sub-polygon trajectory on the feature surface, zizg is the zigzag path algorithm, p j is the intersection point corresponding to the j-th parallel line.

[0039] Furthermore, the determination of the index space specifically is to establish a unified counting reference coordinate system for two point sets and correspond one by one according to the arrangement order to obtain the corresponding relationship between the projected points on the feature surface and the corresponding points on the free form surface, and use the corresponding relationship as the index space.

[0040] Further, calculating the spraying point and spraying posture according to the spraying point index specifically includes: calculating the coordinates and normal vectors of the corresponding points on the free surface according to the spraying point index, and combining the spraying height to calculate the spraying point and spraying posture.

[0041] Further, evaluating the spraying pose path is to calculate indexes of the generated spraying pose path to obtain a weighted evaluation index, and complete the judgment of trajectory execution.

[0042] A free surface spraying path automatic generation device includes a memory and a processor. A computer program is stored on the memory, and when the processor executes the program, the above method is implemented.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) Based on the spraying width, the sub-polygon and offset line segments are divided by parallel lines, and the spraying path is planned according to the obtained intersection points. The overall spraying trajectory can adapt to spraying work with different width requirements, and realize the control of the spraying trajectory to output spraying pose paths with different widths.

[0045] (2) Using sub-polygon division can process free surface point cloud data, not limited to the occasion of known standard CAD models. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a flowchart of the present invention;

[0047] Figure 2 is a schematic diagram of extracting the feature surface and determining the index space of the present invention;

[0048] Figure 3 is a process diagram of path point extraction of the present invention;

[0049] In the figure, 1 is the free surface point cloud, 2 is the feature surface, 3 is the upper boundary surface, 4 is the lower boundary surface, 5 is the robot base coordinate system, 6 is the virtual projection surface, 7 is the index space, and 8 is the local coordinate system. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] The present invention will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and gives the detailed implementation manner and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0051] A free surface spraying path automatic generation method, as Figure 1 shown, includes the following steps:

[0052] Extract the feature surface according to the free surface point cloud data, and determine the index space according to the feature surface and the free surface point cloud data;

[0053] The original polygon on the feature surface is segmented by line segments using the method of sub-polygon division to obtain multiple sub-polygon line segment sets. The sum of the areas enclosed by the sub-polygon line segment sets is equal to the sum of the areas of the original polygon. The sub-polygon line segment sets are connected end to end in sequence to obtain a sub-polygon;

[0054] Based on the sub-polygon, sub-polygon trajectory planning is carried out to obtain a sub-polygon trajectory. Based on the sub-polygon trajectory and the index space, the spraying point index is obtained. According to the spraying point index, the spraying point and the spraying posture are calculated. Based on the spraying point and the spraying posture, the spraying pose path is obtained, and the spraying pose path is evaluated and output.

[0055] As Figure 2 shown, the feature surface 2 is extracted according to the free-form surface point cloud 1, and the schematic diagram of the index space 7 is determined according to the feature surface 2 and the free-form surface point cloud 1.

[0056] The specific steps for extracting the feature surface according to the free-form surface point cloud data and determining the index space according to the feature surface and the free-form surface point cloud data are as follows:

[0057] The free-form surface point cloud 1 is collected by a 3D structured light camera and is a point set data containing surface geometric information, which is spliced from multiple block point cloud data according to the robot coordinate system and the hand-eye calibration matrix. The free-form surface point cloud 1 is represented in the robot base coordinate system 5. The homogeneous transformation is used to express the transformation relationship of each coordinate system, where the pose transformation from the robot end center coordinate system to the robot base coordinate system 5 is represented as E T B , and this matrix can be obtained by reading the coordinate information of the robot control system; the pose transformation from the 3D structured light camera coordinate system to the robot end center coordinate system is represented as C T E , and this matrix can be obtained by hand-eye calibration. Therefore, the expression of the local point cloud of the free-form surface in the robot base coordinate system 5 can be obtained:

[0058]

[0059] In the formula, represents the local point cloud of the free-form surface in the camera coordinate system, B P i represents the local point cloud of the free-form surface in the robot base coordinate system 5. The local point cloud of the free-form surface in the robot base coordinate system 5 B P i is superimposed to obtain the representation of the overall point cloud of the free-form surface in the robot base coordinate system 5:

[0060]

[0061] The feature plane 2 is a plane that exactly distinguishes the point cloud region from the non-point cloud region, that is, there exists a plane:

[0062] Plane feat (x, y, z) = 0: A feat x + B feat y + C feat z + D feat = 0

[0063] The characteristic of this plane is that it can distinguish the point cloud region from the non-point cloud region, that is:

[0064] Plane feat (x p , y p , z p ) > 0

[0065] Plane feat (x np , y np , z np ) < 0

[0066] Among them, Plane feat is the plane function, A feat , B feat , C feat and D feat are the plane coefficients, x p , y p and z p are the points in the point cloud region, and x np , y np and z np are the points in the non-point cloud region.

[0067] The extraction of the feature plane 2 is to calculate the main direction of different point cloud data and find an offset plane that meets the characteristics of the feature plane in the main direction. The main direction of the point cloud data is usually implemented using the PCA algorithm, and the return value is three direction vectors. After calibration, the unit vectors of these three vectors can represent the three coordinate axes of the local coordinate system 8, and their representation is as follows:

[0068] F L = (n x , n y , n z ) = PCA( B P)

[0069] Among them, F L is the local coordinate system of the point cloud data, n x , n y and n z are the three coordinate axis vectors of the local coordinate system, and PCA is the PAC algorithm function. BP is the free-form surface point cloud.

[0070] If the feature plane 2 is perpendicular to the main direction of the point cloud data, then:

[0071] n z ·Plane feat (x,y,z) = 0

[0072] Meanwhile, the origin of the local coordinate system 9 is on the feature plane, so:

[0073] Plane feat (x L ,y L ,z L ) = 0

[0074] where x, y, and z are points on the feature plane, and x L , y L and z L are points in the local coordinate system.

[0075] According to the above constraints, the feature plane 2 can be extracted.

[0076] Based on obtaining the feature plane 2, using the local coordinate system 8, the upper boundary plane 3 and the lower boundary plane 4 can be calculated to satisfy:

[0077] n x ·Plane up (x,y,z) = 0

[0078] n x ·Plane down (x,y,z) = 0

[0079] where n x represents the x-axis of the local coordinate system 8, and Plane up and Plane down represent the upper boundary plane 3 and the lower boundary plane 4 respectively.

[0080] The indexing space 7 is the correspondence between the projection points of the virtual projection plane 6 (i.e., the feature plane 2) on the free-form surface point cloud 1. Define the correspondence between the projection points of the virtual projection plane 6 and the corresponding points on the free-form surface point cloud 1 as:

[0081] χ: feat P → B P

[0082] where χ represents the correspondence between the projection points of the virtual projection plane 6 and the corresponding points on the free-form surface point cloud 1, B P represents the free-form surface point cloud 1.

[0083] The method for determining the index space 7 is to establish a unified counting reference coordinate system for two point sets and make one-to-one correspondences according to the arrangement order. χ has only one-to-one correspondence and no other correspondence.

[0084] The specific steps for segmenting the original polygon on the feature surface by using the method of sub-polygon division to obtain multiple sub-polygon segment sets are as follows:

[0085] A sub-polygon is a set of line segments connected end to end in sequence and is a subset of a composite polygon. Such a polygon is a closed polygon and satisfies the monotonic property in the main direction of the sub-polygon, that is, the number of intersections of any straight line in the vertical direction of this direction with the polygon is equal to 2, and at the vertex position of the polygon, the two intersections coincide. It can be expressed in the following form:

[0086] ξ(l sec ,polygon i )=2||1,l sec ·l first =0

[0087] Among them, ξ represents the number of intersections of the obtained straight line and the polygon, l first represents the straight line in the main direction of the sub-polygon, l sec represents any straight line in the vertical direction of the main direction of the sub-polygon, polygon i represents the sub-polygon.

[0088] The sub-polygon division method is to perform specific line segment division on the original polygon and combine several new line segment sets, and the sum of the areas enclosed by these new line segment sets is equal to the sum of the areas of the original polygon.

[0089] It can be expressed as:

[0090] polygon i =divide(polygon feat ),i∈1,...,n

[0091]

[0092] Among them, polygon i represents the sub-polygon obtained by division, divide represents the division function, polygon feat represents the original polygon on the feature surface, i represents the serial number of the sub-polygon obtained by division, n represents the total number of sub-polygons obtained by division, and aera represents calculating the envelope area of the polygon.

[0093] As Figure 3 shown, the specific steps for performing sub-polygon trajectory planning based on sub-polygons to obtain sub-polygon trajectories are as follows:

[0094] STEP1 Set the offset line segment:

[0095] The offset line segment has two functions. One is to expand the boundary of the sub-polygon to facilitate obtaining the intersection points with the sub-polygon in the parallel line division and inflection point processing STEP2 stage. The other is to map the index of the parallel line to the intersection point with the offset line segment to facilitate representing the serial number of the parallel line. The minimum distance from the points on the sub-polygon to the offset line segment should be greater than a threshold to ensure that the offset line segment does not intersect with the sub-polygon:

[0096]

[0097] where d lploy (·,·) represents the distance from a line to a polygon, represents the offset line segment, min represents the minimum value of an array, and δ represents the minimum offset distance from the offset line segment to the sub-polygon.

[0098] STEP2 Parallel line division:

[0099] The parallel line division and inflection point processing are determined according to the spraying width and the sub-polygon. Each parallel line in the parallel line set is parallel to each other. Each line in the parallel line set has 2 intersection points with the sub-polygon and 1 intersection point with the offset line segment, that is:

[0100]

[0101] At the same time, the intersection point index of each line in the parallel line set with the offset line segment represents the arrangement serial number of the parallel line, that is:

[0102]

[0103] where inx j represents the arrangement serial number, represents the intersection of two lines, represents any line in the parallel line set, represents the line where the offset line segment of the sub-polygon is located, j represents the parallel line serial number, and m represents the number of elements in the parallel line set.

[0104] STEP3 Inflection point processing:

[0105] Judge whether it is an inflection point. If it exists, draw a perpendicular line from the inflection point to the parallel line closest to the inflection point to obtain the inflection point extension line and the intersection point of this parallel line and the inflection point extension line.

[0106] The inflection points are divided into upper inflection points and lower inflection points according to the main direction vector. At this time, the inflection points are also the vertices of the sub-polygon, satisfying:

[0107]

[0108] STEP4 Path Point Extraction:

[0109] Based on the arrangement numbers of the parallel lines, group the intersection points of the parallel lines and the sub-polygon, as well as the intersection points of the parallel lines and the extended lines of the inflection points, to obtain the set of intersection points corresponding to each parallel line.

[0110] Each parallel line satisfies:

[0111]

[0112] Among them, num(p j ) represents the number of intersection points of each group of parallel lines, represents the number of intersection points of the obtained straight line and the processed sub-polygon, represents each straight line in the set of parallel lines, and this parallel line is perpendicular to the main direction straight line l first of the sub-polygon.

[0113] Filter the set of intersection points corresponding to each parallel line to obtain the set of path points corresponding to each parallel line.

[0114] After obtaining the set of path points, connect the path points in the set of path points according to the zigzag path algorithm to obtain the sub-polygon trajectory:

[0115] feat P dep = zizg(∑p j )

[0116] Among them, feat P dep represents the sub-polygon trajectory on the feature plane, zizg represents the zigzag path algorithm, and ∑p j represents all path points.

[0117] Based on the obtained planned trajectory, arrange the trajectory points on the feature plane in order, and find the corresponding points on the free surface through the index space as the basis for calculating the spraying points. Combining the corresponding relationship between the projection points on the feature plane and the corresponding points on the free surface, it can be expressed as:

[0118] B P dep = χ( feat P dep )

[0119] Among them, B P dep represents the sub-polygon trajectory on the free surface, and χ represents the corresponding relationship between the projection points on the feature plane and the corresponding points on the free surface.

[0120] The calculation of spraying points and spraying directions means that based on the completion of the spraying point index, the coordinates and normal vectors of the corresponding points on the free surface are calculated, and combined with the spraying height, the spraying points and spraying directions are calculated and represented by arrows. The free surface point cloud contains the coordinate information of the points. According to the index of the generated sub-polygon trajectory, the normal vectors at the trajectory points are calculated and formed in the following form:

[0121] B Track dep =(X, Y, Z, N x , N y , N z ) = ψ( B P dep )

[0122] Among them, B Track dep represents the coordinate and normal vector of the trajectory points included in the "zigzag" trajectory on the free surface. X, Y, Z, N x , N y , N z represent the set of point coordinates and normal vectors, and ψ represents the function of calculating the normal vectors at the trajectory points according to the index of the generated sub-polygon trajectory.

[0123] Then calculate the spraying points and postures:

[0124]

[0125] Among them, Path pai represents the set of spraying poses of the spray gun, represents the function of calculating the set of spraying poses from the coordinate and normal vector of the trajectory points included in the sub-polygon trajectory on the free surface and the spraying height. h pai represents the spraying height.

[0126] Evaluate the spraying pose path, calculate relevant indicators for the generated spraying pose path, obtain the weighted evaluation index, and accordingly complete the trajectory execution judgment:

[0127]

[0128] Among them, κ represents the evaluation index of the spraying pose path, represents the function of calculating the evaluation index.

[0129] The spraying trajectory after the evaluation of the spraying pose path is issued to drive the actuator to perform the spraying task:

[0130] ret = issue(Path pai )

[0131] Among them, ret represents the return value of the issued instruction, and issue calculates the function of the issued instruction.

[0132] The present invention also provides a free-form surface spraying path automatic generation device, including a memory and a processor. A computer program is stored on the memory, and when the processor executes the program, the above method is implemented.

[0133] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations according to the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention through logical analysis, reasoning, or limited experiments based on the concept of the present invention on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. An automatic generation method for free-form surface spraying paths, characterized in that, it includes the following steps: Extract the feature surface according to the free-form surface point cloud data, and determine the index space according to the feature surface and the free-form surface point cloud data; Use the method of sub-polygon division to segment the original polygon on the feature surface to obtain a plurality of sub-polygon line segment sets. The sum of the areas enclosed by the sub-polygon line segment sets is equal to the sum of the areas of the original polygon. The sub-polygon line segment sets are connected end to end in sequence to obtain a sub-polygon; Based on the sub-polygon, perform sub-polygon trajectory planning to obtain a sub-polygon trajectory. Based on the sub-polygon trajectory and the index space, obtain the spraying point index. Calculate the spraying point and spraying posture according to the spraying point index. Based on the spraying point and spraying posture, obtain the spraying pose path, and evaluate and output the spraying pose path; Among them, the process of trajectory planning is: Set an offset line segment. The offset line segment is outside the sub-polygon and does not intersect with the sub-polygon; Based on the spraying width, perform parallel line division on the sub-polygon and the offset line segment to obtain a set of parallel lines. Each parallel line in the set of parallel lines is parallel to each other, has 2 intersection points with the sub-polygon, and has 1 intersection point with the offset line segment. The index of the intersection point of each parallel line in the set of parallel lines with the offset line segment is the arrangement serial number of the parallel line; Judge whether there are inflection points on the sub-polygon. If there are, draw a perpendicular line from the inflection point to the parallel line closest to the inflection point to obtain the inflection point extension line and the intersection point of the parallel line and the inflection point extension line; Based on the arrangement serial number of the parallel lines, group the intersection points of the parallel lines and the sub-polygon and the intersection points of the parallel lines and the inflection point extension lines to obtain the intersection point set corresponding to each parallel line, Screen the intersection point set corresponding to each parallel line to obtain the path point set corresponding to each parallel line; After obtaining the path point set, connect the path points in the path point set according to the zigzag path algorithm to obtain a sub-polygon trajectory; The specific expression for using the method of sub-polygon division to segment the original polygon on the feature surface is: polygon i = divide(polygon feat ), i ∈ 1,..., n Among them, polygon i is the sub-polygon obtained by division, i is the serial number of the sub-polygon obtained by division, divide is the division function, polygon feat is the original polygon on the feature surface, n is the total number of sub-polygons obtained by division, and aera is the function for calculating the envelope area of the polygon; The constraint conditions of the feature surface are: Plane feat (x,y,z) = 0: A feat x + B feat y + C feat z + D feat = 0 Plane feat (x p ,y p ,z p )>0 Plane feat (x np ,y np ,z np )<0 n z ·Plane feat (x,y,z) = 0 Plane feat (x L ,y L ,z L ) = 0 F L = (n x , n y , n z ) = PCA( B P) where Plane feat is a plane function, x, y, and z are points on the feature surface, A feat , B feat , C feat , and D feat are plane coefficients, x p , y p , and z p are points in the point cloud region, x np , y np , and z np are points in the non-point cloud region, F L is the local coordinate system of the point cloud data, x L , y L , and z L are points in the local coordinate system, n x , n y , and n z are the three axis vectors of the local coordinate system, PCA is the PCA algorithm function, B P is the free-form surface point cloud; The specific determination of the index space is to establish a unified counting reference coordinate system for two point sets and correspond one by one in the arrangement order to obtain the corresponding relationship between the feature surface projection points and the corresponding points of the free-form surface, and use the corresponding relationship as the index space.

2. An automatic generation method for free-form surface spraying paths according to claim 1, characterized in that, The constraint conditions for setting the offset line segment are: where i is the serial number of the sub-polygon obtained by division, is the offset line segment, polygon i is the i-th sub-polygon obtained by division, d lploy is the distance from the offset line segment to the sub-polygon, and δ is the minimum offset distance from the offset line segment to the sub-polygon.

3. An automatic generation method for free-form surface spraying paths according to claim 1, characterized in that, The constraint conditions for screening the intersection point set corresponding to each parallel line are: Among them, j is the arrangement serial number of the parallel lines, and p j is the intersection point corresponding to the j-th parallel line, is a function for calculating the intersection points of the parallel lines and the sub-polygon, is the j-th parallel line in the set of parallel lines, and polygon i is the i-th sub-polygon obtained by division, and l first is polygon i 's main direction line.

4. An automatic generation method for free-form surface spraying paths according to claim 1, characterized in that, The calculation formula for connecting the path points in the path point set according to the zigzag path algorithm is: feat P dep = zizg(∑p j ) Among them, feat P dep is the sub-polygonal trajectory on the feature surface, zizg is the zigzag path algorithm, and p j is the intersection point corresponding to the j-th parallel line.

5. An automatic generation method for free-form surface spraying paths according to claim 1, characterized in that, Specifically, calculating the spraying point and spraying posture according to the spraying point index means: calculating the coordinates and normal vectors of the corresponding points on the free-form surface according to the spraying point index, and combining the spraying height to calculate the spraying point and spraying posture.

6. A method for automatically generating a spraying path for a free-form surface according to claim 1, wherein, evaluating the spraying pose path is to calculate indexes for the generated spraying pose path to obtain a weighted evaluation index and complete the judgment of trajectory execution.

7. A device for automatically generating a spraying path for a free-form surface, comprising a memory and a processor, and a computer program is stored on the memory, wherein, when the processor executes the program, the method described in any one of claims 1 to 6 is implemented.

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