A method for generating spraying paths based on CAD digital model surface information data

Abstract

The present invention provides a method for generating a spray path based on CAD digital model surface information data, which belongs to the field of automatic tool path generation, and includes the following steps: 1) establishing a surface information data structure, and setting process parameters: spray overlap distance and spray distance. 2) determining the spray direction and whether spraying is possible based on the surface information data, storing the surface data, generating topological information, obtaining topological data of the relationship between surfaces, and generating combined surface weight data based on the surface data and the surface topological data. 3) finding the surface with the largest weight from the combined surface vector (surface topological data), and automatically generating a spray path, and then finding the surface with the largest weight from the remaining surface topological data to generate a spray path, and so on, until the spray path planning of all combined surfaces is completed.

Description

Technical Field

[0001] The invention belongs to the field of automatic tool path generation, and relates to a method for automatically generating a spraying path based on CAD digital model surface information data. Background Art

[0002] All workpieces will go through a spraying process before leaving the factory to improve the corrosion resistance and aesthetics of the product. Manual spraying has problems such as high labor intensity and low spraying efficiency, and harmful gases will be generated during the spraying process, which will cause harm to the body. The current spraying robots are only suitable for production lines with large product batches and fixed specifications. They cannot meet the needs of spraying operations with small parts, a wide variety, and complex surface shapes. The spraying paths for parts with fixed specifications are also manually taught by spraying or manually interactive offline programming using special software. This is not suitable for the generation of spraying paths for small parts and a wide variety of parts with complex surface shapes.

[0003] In order to solve the problem of path planning for spraying operations of numerous and complex small parts, from the perspective of improving work efficiency, improving spraying quality, and saving spraying path planning time, it is necessary to start from the path generation method and find a calculation method that can automatically generate a variety of complex small parts spraying operation paths. Summary of the invention

[0004] The present invention mainly solves the problem of automatic generation of spraying operation paths of parts with many types and complex surfaces, and proposes a method for realizing automatic generation of spraying paths based on surface information data of CAD digital model, wherein the surface information data includes the posture matrix of the surface, the coordinates of the center of mass of the surface, the surface normal, the area size of the surface, the maximum x coordinate of the surface edge, the maximum y coordinate of the surface edge, the minimum x coordinate of the surface edge, the minimum y coordinate of the surface edge, the surface index, the main direction vector, the main direction length, etc. First, set the spraying overlap distance and the spraying distance. Then, the surface information data of the digital model is processed to obtain the surface data and the topological information data of the combined surface, and the combined surface weight data is generated according to the surface data and the combined surface topological data. The combined surface can be three-surface intersection, two-surface intersection, single surface, etc., and the combined surface topological data includes the index of adjacent surfaces, the starting point of the main direction of spraying, and the end point of the main direction of spraying. Find the surface with the largest weight from the combined surface vector (surface topological data), and automatically generate the spraying path, and then find the surface with the largest weight from the remaining surface topological data to generate the spraying path, and so on, the spraying path planning of all combined surfaces is completed.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for generating a spraying path based on CAD digital model surface information data includes the following steps:

[0007] The first step is to read the surface information data of the part and set the spray overlap distance and spray distance. The surface information data includes the surface pose matrix, surface centroid coordinates, surface normal, surface area, surface index, and temporary spray direction of the surface.

[0008] The second step is to determine the tentative spraying direction and whether spraying is possible based on the surface information data, and store it in the surface data vector.

[0009] The third step is to generate the combined surface topology data. The direction of the spray gun and the direction of the spray path must be determined first, and the quaternion of the spray gun's posture is determined on this basis.

[0010] Write the combined surface information of two or three intersecting surfaces into the surface topology data vector. The surface topology data includes the topological connection surface index, spray gun direction, spray path direction starting point, spray path direction end point, spray gun posture quaternion, etc.

[0011] The fourth step is to calculate the weight of a single face in the face data and the weight of a combined face of two or three faces intersecting in the face topology data based on the area information. The generated weight information is written into the face weight data.

[0012] The fifth step is to find the combined face or single face with the largest weight and unplanned path from the face weight data. The combined face determines the spraying plane and spray gun posture of the combined face according to the intersection line and the extreme point of the face. The single face uses its own plane as the spraying plane and its own spray gun posture as the spray gun posture of the spraying plane. Finally, the spraying path of the spraying plane is planned based on the spraying plane and the spray gun posture. Traverse the search until the path planning of all combined faces or single faces with unplanned paths is completed.

[0013] The beneficial effects of the present invention are:

[0014] The present invention aims at the situation that the current offline spraying path planning is inefficient and not suitable for batch spraying of parts with many varieties and complex surfaces. By setting the spraying overlap distance and spraying distance, the developed algorithm is used to automatically generate the spraying path, thereby improving the efficiency and quality of the spraying operation. The method proposed by the present invention can quickly generate the spraying path, reduce labor costs, and improve operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Generate an overall flow chart for the inventive path. DETAILED DESCRIPTION

[0016] In order to make the method problems solved by the present invention, the method solutions adopted and the method effects achieved clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It is also necessary to explain that, for the convenience of description, only the parts related to the present invention are shown in the accompanying drawings, rather than all the contents.

[0017] like Figure 1 As shown, an embodiment of the present invention provides a method for automatically generating a spray path based on CAD digital model surface information data, including: first, establishing a surface information data structure, and setting process parameters: spray overlap distance and spray distance. Secondly, determine the spray direction and whether it can be sprayed according to the surface information data, store the surface data, generate topological information, obtain the topological data of the relationship between the surfaces, and generate combined surface weight data based on the surface data and the surface topology data. Finally, find the surface with the largest weight from the combined surface vector (surface topology data) to automatically generate the spray path, and then find the surface with the largest weight from the remaining surface topology data to generate the spray path, and so on, until the spray path planning of all combined surfaces is completed. Specifically including the following steps:

[0018] The first step is to read the face information data of the part from the disk path face_info_path and set the spray overlap distance pathwidth and the spray distance pathdistance.

[0019] The second step is to determine the tentative spraying direction and whether spraying is possible based on the surface information data RTed_face_information, and store it in the surface data facedata vector. Specifically:

[0020] Establish the coordinate system of the platform carrier where the part is located, traverse all surface information data, determine whether the surface can be sprayed according to the relationship between the surface normal vector and the platform coordinate system, determine the temporary spraying direction according to the main direction of the surface and the main direction length, and write the complete data into the surface data vector. The surface data includes the surface center coordinates, surface normal, surface area, maximum x, maximum y, minimum x, minimum y coordinate values ​​of the surface contour, surface index, surface main direction, surface main direction length, temporary spraying direction of the surface, and whether it can be sprayed.

[0021] The third step is to generate the combined surface topology data facetopodata. The direction of the spray gun and the direction of the spray path must be determined first, and the quaternion of the spray gun's posture is determined on this basis.

[0022] Find the topological relationship between two faces according to the face data, that is, whether they are topologically connected faces. For two intersecting faces, determine the direction of the combined face spray gun according to the area weight:

[0023] Aa=faces_areasize[a]*a_normal+faces_areasize[b]*b_normal

[0024] Aa.normalize()

[0025] For two intersecting faces, find the faces that they both intersect to determine whether it is a three-face intersection. For three-face intersection, determine the combined face spray gun direction based on the area weights of the three intersecting faces:

[0026] Aa=faces_areasize[a]*a_normal+faces_areasize[b]*b_normal+faces_areasize[c]*c_normal

[0027] Aa.normalize()

[0028] The spray path direction of two-surface intersection is determined by the projection points of the extreme points of the two surfaces on their intersection line. The composite spray path of three-surface intersection is determined by the projection points of the extreme points of the two largest surfaces on their intersection line.

[0029] A coordinate system is established with the spray gun posture as the z-axis and the synthesized spray path as the y-axis to determine the spray posture quaternion.

[0030] Write the combined surface information of two or three intersecting surfaces into the surface topology data vector. The surface topology data includes the topological connection surface index, spray gun direction, spray path direction starting point, spray path direction end point, spray gun posture quaternion, etc.

[0031] The fourth step is to calculate the weight of a single face in the face data and the weight of a combined face of two or three faces intersecting in the face topology data based on the area information. The generated weight information is written into the face weight data.

[0032] The fifth step is to find the combined face or single face with the largest weight and unplanned path from the face weight data. Then, for the case of three-face intersection, determine the spray plane and spray gun posture according to the area weight and the direction of the intersection line of the three faces that intersect each other. For the case of two-face intersection, determine the spray plane and its spray gun posture according to the spray gun direction and intersection line of the two faces. For the case of a single face, its own plane and spray gun posture are used as the spray plane and its spray gun posture, where the boundary points of the spray plane are polygons formed by connecting the projection points of the extreme points of the combined face (or single face) on the spray plane. Finally, plan the spray path information based on the spray plane combined with the spray gun posture. Until the path planning of all combined faces or single faces is completed.

[0033] The above-described embodiments merely express the implementation methods of the present invention, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for generating a spraying path based on CAD digital model surface information data, characterized in that: The following steps are involved: The first step is to read the surface information data of the part and set the spray overlap distance and spray distance; the surface information data includes the surface pose matrix, surface centroid coordinates, surface normal, surface area, surface index, and temporary spray direction of the surface; The second step is to determine the temporary spraying direction and whether it can be sprayed according to the surface information data, and store it in the surface data vector; specifically: establish the coordinate system of the platform carrier where the part is located, traverse all surface information data, determine whether the surface can be sprayed according to the relationship between the surface normal vector and the platform coordinate system, determine the temporary spraying direction according to the main direction and main direction length of the surface, and write the complete data into the surface data vector; The third step is to generate the combined surface topology data; first determine the direction of the spray gun and the direction of the spray path, and then determine the posture quaternion of the spray gun on this basis; According to the surface data, find the topological relationship between two surfaces, that is, whether they are topologically connected surfaces. For two intersecting surfaces, determine the direction of the combined surface spray gun according to the area weight; and for two intersecting surfaces, find the surfaces that they intersect to determine whether it is a three-surface intersection; for the case of three-surface intersection, determine the direction of the combined surface spray gun according to the area weights of the three intersecting surfaces; The direction of the spray path of two intersecting surfaces is determined by the projection points of the extreme points of the two surfaces on their intersection line; the composite spray path of three intersecting surfaces is determined by the projection points of the extreme points of the two largest surfaces on their intersection line; Write the combined surface information of two or three intersecting surfaces into the surface topology data vector, where the surface topology data includes the topological connection surface index, the spray gun direction, the starting point of the spray path direction, the end point of the spray path direction, and the spray gun posture quaternion; The fourth step is to calculate the weight of a single face in the face data and the weight of a combined face of two or three faces intersecting in the face topology data based on the area information; the generated weight information is written into the face weight data; Step 5. Find the combined face or single face with the largest weight and unplanned path from the face weight data, where the spray plane and spray gun posture of the combined face are determined according to the intersection lines and extreme points of the faces, and the single face uses its own plane as the spray plane, and its own spray gun posture as the spray gun posture of the spray plane; finally, plan the spray path of the spray plane based on the spray plane and the spray gun posture; traverse the search until the path planning of all combined faces or single faces with unplanned paths is completed.

2. A method for generating a spraying path based on CAD digital model surface information data according to claim 1, characterized in that: In the third step, a coordinate system is established with the spray gun posture as the z-axis and the synthesized spray path as the y-axis to determine the spray posture quaternion.

3. A method for generating a spraying path based on CAD digital model surface information data according to claim 1, characterized in that: In the fifth step, the boundary points of the spraying plane are polygons formed by connecting lines of projection points of the extreme points of the combined surface or single surface on the spraying plane.

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