Visual guidance variable curvature airfoil skin robot fairing processing path generation method

Abstract

The invention belongs to the technical field of machining path planning, and particularly discloses a visual guidance variable curvature airfoil skin robot fairing machining path generation method which comprises the steps that three-dimensional point cloud data of an airfoil skin to be machined is collected, the three-dimensional point cloud data is preprocessed, and the three-dimensional point cloud data is obtained; converting the three-dimensional point cloud data into a triangular mesh curved surface by adopting a point cloud triangular meshing algorithm; based on the geodesic distance between any two points on the triangular mesh curved surface, mapping the point set of the triangular mesh curved surface into a plane space to obtain a corresponding plane point set, and then obtaining boundary points of the plane point set in the plane space according to local neighborhood features of the boundary points, reversely mapping the boundary points in the plane point set to the curved surface point set to obtain airfoil skin boundary contour points; and fitting the airfoil skin boundary contour points on the basis of the curvature characteristics of the airfoil skin boundary contour points to obtain a B spline curve, and obtaining processing path points on the basis of the B spline curve.

Description

Technical Field

[0001] The present application belongs to the technical field of processing path planning, and more specifically, to a method for generating a smooth processing path for a variable curvature airfoil skin robot guided by vision. Background Art

[0002] The wing skin is mainly formed by drawing and milling, and then riveted to the aircraft frame in sections. Since various errors may occur during the manufacturing and assembly process, processing allowances are usually reserved during the skin blank processing stage, and the adjacent skins are trimmed during assembly. At present, it is generally adopted to remove the processing allowance at the assembly position by workers repeatedly comparing with the naked eye and manually trimming to ensure that the gap between the adjacent skins meets the design requirements. However, this method requires high proficiency of workers, has high randomness, low efficiency and difficulty in ensuring consistency.

[0003] Compared with traditional CNC machine tools, industrial robots have the characteristics of large processing range, high flexibility, and good dexterity, which are very suitable for the automated trimming of airfoil skins. However, due to the thin-walled and weak rigidity of airfoil skins, and the large deformation after clamping and positioning, the design model cannot be used directly to plan the processing path, and the robot processing path can only be generated through the on-site measurement points of the visual sensor. The existing methods of generating processing paths using measurement points are mostly only used for flat parts with small curvature, and cannot directly generate robot processing paths for airfoil skins, or problems such as low processing path accuracy occur. Summary of the invention

[0004] In view of the defects of the prior art, the purpose of the present application is to provide a vision-guided method for generating a smooth processing path for a variable curvature airfoil skin robot, aiming to solve the problem that most of the robot processing path methods in the prior art are only used for planar parts with small curvature, resulting in low accuracy of the robot processing path for generating airfoil skin.

[0005] To achieve the above objectives, in a first aspect, the present application provides a method for generating a smooth machining path for a variable curvature airfoil skin robot guided by vision, comprising: Collecting three-dimensional point cloud data of the airfoil skin to be processed, preprocessing the three-dimensional point cloud data, and converting the three-dimensional point cloud data into a triangular mesh surface using a point cloud triangular meshing algorithm; Based on the geodesic distance between any two points on the triangular mesh surface, a triangular mesh surface point set is mapped into a plane space to obtain a corresponding plane point set, and then boundary points of the plane point set are obtained in the plane space according to the local neighborhood characteristics of the boundary points, and the boundary points in the plane point set are inversely mapped into the surface point set to obtain boundary contour points of the airfoil skin; Based on the curvature characteristics of the airfoil skin boundary contour points, the airfoil skin boundary contour points are fitted to obtain a B-spline curve, and processing path points are obtained based on the B-spline curve.

[0006] After collecting the three-dimensional point cloud data of the airfoil skin to be processed, the application performs preprocessing to filter out noise points on the one hand and reduce the density of the measurement data on the other hand. The three-dimensional point cloud data is then converted into a triangular mesh surface for mapping to obtain a corresponding plane point set. The boundary points of the plane point set are obtained in the plane space according to the local neighborhood characteristics of the boundary points. The boundary contour points of the airfoil skin are obtained by inverse mapping. This is easy to implement. According to the curvature characteristics of the boundary contour points of the airfoil skin, the boundary contour points of the airfoil skin are fitted by a B-spline curve. This can not only ensure the smoothness of the processing path and avoid jitter, but also ensure the accuracy of the processing path and improve the processing accuracy.

[0007] According to a visually guided variable curvature airfoil skin robot smoothing processing path generation method provided in the present application, the three-dimensional point cloud data is converted into a triangular mesh surface using a point cloud triangular meshing algorithm, including: The three-dimensional point cloud data is converted into a triangular mesh surface using the Lawson algorithm or the Bowyer-Watson algorithm.

[0008] According to a visually guided variable curvature airfoil skin robot smoothing processing path generation method provided by the present application, the triangular mesh surface point set is mapped into a plane space based on the geodesic distance between any two points on the triangular mesh surface to obtain a corresponding plane point set, including: Based on the geodesic distance between any two points on the triangular mesh surface, a multi-dimensional scaling method is used to map the triangular mesh surface point set into a plane space to obtain a corresponding plane point set.

[0009] According to a visually guided variable curvature airfoil skin robot smoothing processing path generation method provided by the present application, the boundary points of the plane point set are obtained according to the local neighborhood features of the boundary points in the plane space, including: Traversing a plane point set Each point in , query with the point The nearest k points , choose any point With point Composition vector ; Vector As the benchmark, traverse the remaining points With point Composition vector , and calculate the vector With vector Angle , and calculate the vector With vector If the outer product is positive, then unchanged, if the outer product is negative, then Take its opposite number; Record The maximum value of and minimum value ,like If the angle is smaller than the preset threshold, the point As the boundary points of a plane point set.

[0010] The present application obtains the boundary points of the plane point set in the plane space according to the angle between each point and the vector formed by its surrounding points, and obtains the boundary contour points of the airfoil skin by inverse mapping. It is easy to implement, and the size of the angle can be set to different values ​​according to the shape of the airfoil skin, so it has strong applicability.

[0011] According to a visually guided variable curvature airfoil skin robot smoothing processing path generation method provided by the present application, the airfoil skin boundary contour points are fitted based on the curvature characteristics of the airfoil skin boundary contour points to obtain a B-spline curve, including: Calculate the parameter value and curvature value corresponding to each airfoil skin boundary contour point; Based on the parameter value and the curvature value, construct a characteristic function reflecting the geometric characteristics of the airfoil skin, and calculate a cumulative distribution function based on the characteristic function; A knot vector is calculated based on the parameter value, and a fitted B-spline curve is obtained based on the cumulative distribution function and the knot vector.

[0012] The present application configures node vectors according to the curvature characteristics of the airfoil skin boundary contour points, and fits the airfoil skin boundary contour points through B-spline curves to ensure the smoothness of the processing path, avoid jitter, and ensure the accuracy of the processing path and improve the processing accuracy.

[0013] According to a vision-guided variable curvature airfoil skin robot smoothing processing path generation method provided by the present application, the processing path points are obtained based on the B-spline curve, including: The B-spline curve is discretized by using an equal chord length method or an equal residual method to obtain processing path points.

[0014] According to a visually guided variable curvature airfoil skin robot smoothing processing path generation method provided by the present application, after fitting the airfoil skin boundary contour points based on the curvature characteristics of the airfoil skin boundary contour points to obtain a B-spline curve, and obtaining the processing path points based on the B-spline curve, the method further includes: The processing path point position and the corresponding processing posture are converted into the joint angle of the robot at the processing position point based on the robot inverse kinematics.

[0015] The present application uses robot inverse kinematics to convert the position of a processing path point and the corresponding processing posture into the joint angle of the robot at the processing position point, so that the industrial robot can realize automatic trimming of the airfoil skin based on the generated processing path.

[0016] In a second aspect, the present application provides a vision-guided variable curvature airfoil skin robot smoothing processing path generation device, comprising: An acquisition module is used to acquire three-dimensional point cloud data of the airfoil skin to be processed, pre-process it, and convert the three-dimensional point cloud data into a triangular mesh surface using a point cloud triangular meshing algorithm; A boundary extraction module is used to map a triangular mesh surface point set into a plane space based on the geodesic distance between any two points on the triangular mesh surface to obtain a corresponding plane point set, then obtain boundary points of the plane point set according to local neighborhood features of the boundary points in the plane space, and inversely map the boundary points in the plane point set into the surface point set to obtain boundary contour points of the airfoil skin; A fitting module is used to fit the airfoil skin boundary contour points based on the curvature characteristics of the airfoil skin boundary contour points to obtain a B-spline curve, and obtain processing path points based on the B-spline curve.

[0017] In a third aspect, the present application provides an electronic device comprising: at least one memory for storing programs; and at least one processor for executing the programs stored in the memory. When the programs stored in the memory are executed, the processor is used to execute the vision-guided variable curvature wing skin robot smoothing processing path generation method described in the first aspect or any possible implementation of the first aspect.

[0018] In a fourth aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the vision-guided variable curvature wing skin robot smooth processing path generation method described in the first aspect or any possible implementation of the first aspect.

[0019] In a fifth aspect, the present application provides a computer program product. When the computer program product runs on a processor, the processor executes the vision-guided variable curvature wing skin robot smooth processing path generation method described in the first aspect or any possible implementation of the first aspect.

[0020] It can be understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0021] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art: After collecting the three-dimensional point cloud data of the airfoil skin to be processed, preprocessing is performed to filter out noise points on the one hand and reduce the density of the measurement data on the other hand. The three-dimensional point cloud data is then converted into a triangular mesh surface for mapping to obtain the corresponding plane point set. The boundary points of the plane point set are obtained in the plane space according to the local neighborhood characteristics of the boundary points. The boundary contour points of the airfoil skin are obtained through inverse mapping, which is easy to implement. According to the curvature characteristics of the boundary contour points of the airfoil skin, the boundary contour points of the airfoil skin are fitted through the B-spline curve, which can not only ensure the smoothness of the processing path and avoid jitter, but also ensure the accuracy of the processing path and improve the processing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is one of the flow diagrams of the method for generating a smoothing processing path of a variable curvature airfoil skin robot guided by vision provided in an embodiment of the present application; Figure 2 This is a schematic diagram of the principle of obtaining boundary points in a plane point set provided by an embodiment of the present application; Figure 3 It is a schematic diagram of obtaining the processing path points of the airfoil skin robot by using the equal chord length method discrete curve provided in an embodiment of the present application; Figure 4 It is a structural schematic diagram of a device for generating a smoothing processing path for a variable curvature airfoil skin robot guided by vision provided in an embodiment of the present application; Figure 5 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] The term "and / or" in this article is a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The symbol " / " in this article indicates that the associated objects are in an or relationship, for example, A / B means A or B.

[0026] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0027] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more than two. For example, multiple processing units refer to two or more processing units, etc.; multiple elements refer to two or more elements, etc.

[0028] Next, combine Figure 1-Figure 3 The vision-guided variable curvature wing skin robot smooth processing path generation method provided in the embodiment of the present application is introduced.

[0029] Figure 1 is a flow chart of a method for generating a smooth machining path for a variable curvature airfoil skin robot guided by vision provided in an embodiment of the present application, such as Figure 1 As shown, the method comprises the following steps: Step 100, collecting three-dimensional point cloud data of the airfoil skin to be processed, preprocessing the three-dimensional point cloud data, and converting the three-dimensional point cloud data into a triangular mesh surface using a point cloud triangular meshing algorithm; Optionally, three-dimensional point cloud data of the airfoil skin to be processed may be collected by a collection device such as a laser radar or an ultrasonic sensor.

[0030] Optionally, preprocessing methods such as outlier removal, smoothing filtering or random downsampling can be used to preprocess the three-dimensional point cloud data to remove noise generated during the measurement process and reduce the density of the measurement data.

[0031] The point cloud triangulation algorithm is an algorithm that converts discrete three-dimensional point cloud data into a continuous surface, including Delaunay triangulation, etc. This application does not limit the specific point cloud triangulation algorithm used to convert three-dimensional point cloud data into a triangular mesh surface.

[0032] Step 110, based on the geodesic distance between any two points on the triangular mesh surface, the triangular mesh surface point set is mapped into the plane space to obtain the corresponding plane point set, then the boundary points of the plane point set are obtained in the plane space according to the local neighborhood characteristics of the boundary points, and the boundary points in the plane point set are inversely mapped into the surface point set to obtain the boundary contour points of the airfoil skin; The triangular mesh surface is obtained, and the surface point set can be mapped into the plane space based on the geodesic distance between any two points on the surface to obtain the plane point set, and the boundary points in the plane space are determined. The boundary points of the plane point set are obtained according to the local neighborhood characteristics of the boundary points, and then the boundary points of the plane point set are mapped into the surface point set through inverse mapping to obtain the boundary contour points of the airfoil skin.

[0033] Step 120 , fitting the airfoil skin boundary contour points based on the curvature characteristics of the airfoil skin boundary contour points to obtain a B-spline curve, and obtaining processing path points based on the B-spline curve.

[0034] Optionally, the node vectors can be configured according to the curvature characteristics of the airfoil skin boundary contour points, the airfoil skin boundary contour points can be fitted by a B-spline curve, and then the airfoil skin robot processing path points can be obtained by curve discretization.

[0035] The present application provides a vision-guided variable curvature airfoil skin robot smooth processing path generation method. After collecting the three-dimensional point cloud data of the airfoil skin to be processed, preprocessing is performed to filter out noise points on the one hand and reduce the density of the measurement data on the other hand. The three-dimensional point cloud data is then converted into a triangular mesh surface for mapping to obtain a corresponding plane point set. The boundary points of the plane point set are obtained in the plane space according to the local neighborhood characteristics of the boundary points. The boundary contour points of the airfoil skin are obtained by inverse mapping. The method is easy to implement. According to the curvature characteristics of the boundary contour points of the airfoil skin, the boundary contour points of the airfoil skin are fitted by a B-spline curve. This method can not only ensure the smoothness of the processing path and avoid jitter, but also ensure the accuracy of the processing path and improve the processing accuracy.

[0036] In some embodiments, step 100 specifically includes: The Lawson algorithm or Bowyer-Watson algorithm is used to convert three-dimensional point cloud data into triangular mesh surfaces.

[0037] The Lawson algorithm is a local optimization algorithm, mainly used to generate two-dimensional Delaunay triangulation. Its core idea is to gradually optimize the triangular mesh by flipping edge by edge to ensure that the Delaunay criterion is met. The algorithm steps include: 1a. Input: a set of two-dimensional points ; 2a. Generate an initial triangulation, which can be any simple triangulation, such as a convex hull triangulation or a randomly generated triangle mesh; 3a. Local optimization iteration: traverse all edges, check whether they meet the Delaunay condition, and perform flip operations on edges that do not meet the condition; 4a. Termination condition: All edges satisfy the Delaunay criterion and the algorithm converges.

[0038] The Bowyer-Watson algorithm is a classic incremental Delaunay triangulation algorithm that dynamically maintains the Delaunay triangulation by inserting points one by one. The algorithm steps include: 1b. Input: a set of two-dimensional points ; 2b. Initialize the super triangle: Create a triangle large enough to surround all input points and ensure that all subsequent insertion points are inside the triangle; 3b. Insert each point into the current triangulation in turn; 4b. Delete all triangles containing super-triangle vertices, leaving a triangular mesh consisting only of the input points.

[0039] Optionally, the Lawson algorithm or the Bowyer-Watson algorithm may be used to convert the three-dimensional point cloud data into a triangular mesh surface to improve conversion efficiency and practicality.

[0040] In some embodiments, step 110 maps the triangular mesh surface point set to the plane space based on the geodesic distance between any two points on the triangular mesh surface to obtain the corresponding plane point set, specifically including: Based on the geodesic distance between any two points on the triangular mesh surface, the multi-dimensional scaling method is used to map the triangular mesh surface point set into the plane space to obtain the corresponding plane point set.

[0041] First, assume that the surface point set is , calculate the geodesic distances from some points to other points on the triangular mesh surface, and quickly approximate the matrix consisting of geodesic distances between points by multiplying small matrices ,get , its objective function is:

[0042] in, For the matrix of any n columns. If is unknown, transform the above formula into:

[0043] in, For the matrix The first n rows of . Solving for The expression is .

[0044] Then, the surface point set is mapped to the corresponding plane point set using the multidimensional scaling method, and its objective function is:

[0045] in, is an s×s matrix, , is the i-th point on the triangular mesh surface With the jth point The geodesic distance of is a s×s centered matrix, and , among which, when hour ,when hour , through the matrix The obtained plane point set can be The geometric center of is moved to the origin of coordinates. Performing eigenvalue decomposition yields:

[0046] in, is a diagonal matrix whose diagonal elements are The eigenvalues ​​of are arranged from large to small, and the matrix It is composed of the eigenvectors corresponding to the eigenvalues, and the corresponding plane point set is obtained as follows:

[0047] in, for The diagonal matrix consisting of the two largest eigenvalues ​​in , for The matrix consisting of the corresponding eigenvectors in .

[0048] In some embodiments, obtaining the boundary points of the plane point set according to the local neighborhood features of the boundary points in the plane space in step 110 specifically includes: Traversing a plane point set Each point in , query and point The nearest k points , choose any point With point Composition vector ; Vector As the benchmark, traverse the remaining points With point Composition vector , and calculate the vector With vector Angle , and calculate the vector With vector If the outer product is positive, then unchanged, if the outer product is negative, then Take its opposite number; Record The maximum value of and minimum value ,like If the angle is smaller than the preset threshold, the point As the boundary points of a plane point set.

[0049] Figure 2 Schematic diagram of the principle of obtaining boundary points in a plane point set provided by an embodiment of the present application, such as Figure 2 As shown, traverse the plane point set Each point in , query the k points closest to it , choose any point With point Composition vector , with vector As the benchmark, traverse the remaining points With point Composition vector , calculate the vector With vector Angle , further calculate the vector With vector If the outer product is positive, then unchanged, if the outer product is negative, then Take its opposite number and record The maximum value of and minimum value ,like This point can be obtained is the boundary point in the plane point set.

[0050] in, Any point in the plane point set The angle between the vector formed by the surrounding points can be set according to the geometric shape of the airfoil skin.

[0051] In some embodiments, step 120 specifically includes: Calculate the parameter value and curvature value corresponding to each airfoil skin boundary contour point; Based on the parameter values ​​and curvature values, a characteristic function reflecting the geometric characteristics of the airfoil skin is constructed, and a cumulative distribution function is calculated based on the characteristic function; The knot vector is calculated based on the parameter value, and the fitted B-spline curve is obtained based on the cumulative distribution function and the knot vector.

[0052] The specific steps are as follows: 1c. Use the cumulative chord length parameterization method to calculate the parameter value corresponding to each airfoil skin boundary contour point :

[0053] 2c. Fit the airfoil skin boundary contour points with lower fitting accuracy to obtain the base curve , calculate the curvature value of each airfoil skin boundary contour point for:

[0054] in, is the base curve obtained by fitting with lower fitting accuracy, , The base curves In parameter value The first and second derivatives at .

[0055] 3c. Constructing characteristic functions that reflect the geometric characteristics of the airfoil skin , let the characteristic function be at parameter value is the curvature value of the airfoil skin boundary contour point ,Right now: , and then define the continuous characteristic function in the form of piecewise linear interpolation , whose expression is:

[0056] 4c. Calculate the characteristic function reflecting the geometric characteristics of the airfoil skin The cumulative distribution function of For dense data, the Newton-Cotes formula is used to calculate the integral:

[0057] 5c. Calculate node vector In order to make the endpoint of the B-spline curve coincide with the control point, the k+1 nodes before and after are the same, and the values ​​of the nodes before and after are , , the value of the intermediate node is ,in is the inverse of the cumulative distribution function, The feature values ​​contained in each node are set.

[0058] 6c. Node vectors configured based on the curvature characteristics of the airfoil skin boundary contour points U , the B-spline curve is used to fit the airfoil skin boundary contour points, and its least square fitting expression is:

[0059] in, , , ,

[0060] Where k is the degree of the B-spline curve, is the basis function of the B-spline curve.

[0061] Furthermore, through the control point D and the node vector U The expression of the fitted B-spline curve is: .

[0062] In some embodiments, step 120 specifically includes: The equal chord length method or the equal residual method is used to discretize the B-spline curve to obtain the processing path points.

[0063] Figure 3 Schematic diagram of obtaining the processing path points of the airfoil skin robot by using the equal chord length method discrete curve provided in the embodiment of the present application, such as Figure 3 As shown, in one embodiment of the present application, the airfoil skin boundary contour points are fitted to obtain a fitting curve Then, the fitting curve is converted into The smooth robot machining path points of the airfoil skin can be obtained by discretization.

[0064] Optionally, the equal residual method can be used to fit the curve The smooth robot machining path points of the airfoil skin can be obtained by discretization.

[0065] In some embodiments, after step 120, the method further includes: Based on the inverse kinematics of the robot, the position of the processing path point and the corresponding processing posture are converted into the joint angle of the robot at the processing position point.

[0066] Robot inverse kinematics is a key technology for achieving precise trajectory planning, obstacle avoidance control and real-time operation. It aims to solve the motion parameters of each joint of the robot (such as rotation angle, translation distance) based on the target position and posture of the end effector (such as manipulator, foot or tool).

[0067] The present application uses robot inverse kinematics to convert the position of a processing path point and the corresponding processing posture into the joint angle of the robot at the processing position point, so that the industrial robot can realize automatic trimming of the airfoil skin based on the generated processing path.

[0068] Figure 4 is a schematic diagram of the structure of a visually guided variable curvature airfoil skin robot smoothing processing path generation device provided in an embodiment of the present application, such as Figure 4 As shown, the system includes a collection module 410, a boundary extraction module 420 and a fitting module 430, wherein: The acquisition module 410 is used to acquire the three-dimensional point cloud data of the airfoil skin to be processed, pre-process it, and convert the three-dimensional point cloud data into a triangular mesh surface using a point cloud triangular meshing algorithm; Boundary extraction module 420, for mapping a triangular mesh surface point set into a plane space based on the geodesic distance between any two points on the triangular mesh surface to obtain a corresponding plane point set, then obtaining boundary points of the plane point set according to local neighborhood features of the boundary points in the plane space, and inversely mapping the boundary points in the plane point set into the surface point set to obtain boundary contour points of the airfoil skin; The fitting module 430 is used to fit the airfoil skin boundary contour points based on the curvature characteristics of the airfoil skin boundary contour points to obtain a B-spline curve, and obtain processing path points based on the B-spline curve.

[0069] It should be understood that the above-mentioned system is used to execute the methods in the above-mentioned embodiments. The implementation principles and technical effects of the corresponding program modules in the system are similar to those described in the above-mentioned methods. The working process of the system can refer to the corresponding process in the above-mentioned method and will not be repeated here.

[0070] Based on the method in the above embodiment, Figure 5 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 5As shown, an embodiment of the present application provides an electronic device, which may include: a processor 510, a communication interface 520, a memory 530 and a communication bus 540, wherein the processor 510, the communication interface 520, and the memory 530 communicate with each other through the communication bus 540. The processor 510 may call the logic instructions in the memory 530 to execute the visually guided variable curvature airfoil skin robot smoothing processing path generation method in the above embodiment.

[0071] In addition, the logic instructions in the above-mentioned memory 530 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the visual-guided variable curvature airfoil skin robot smoothing processing path generation method described in each embodiment of the present application.

[0072] Based on the method in the above embodiment, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the vision-guided variable curvature wing skin robot smoothing processing path generation method in the above embodiment.

[0073] Based on the method in the above embodiment, an embodiment of the present application provides a computer program product. When the computer program product runs on a processor, the processor executes the vision-guided variable curvature wing skin robot smoothing processing path generation method in the above embodiment.

[0074] It is understandable that the processor in the embodiment of the present application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0075] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC.

[0076] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions may be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)), etc.

[0077] It should be understood that the various numerical numbers involved in the embodiments of the present application are only used for the convenience of description and are not used to limit the scope of the embodiments of the present application.

[0078] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A vision-guided variable curvature airfoil skin robot smoothing processing path generation method, characterized in that: include: Collecting three-dimensional point cloud data of the airfoil skin to be processed, preprocessing the three-dimensional point cloud data, and converting the three-dimensional point cloud data into a triangular mesh surface using a point cloud triangular meshing algorithm; Based on the geodesic distance between any two points on the triangular mesh surface, a triangular mesh surface point set is mapped into a plane space to obtain a corresponding plane point set, and then boundary points of the plane point set are obtained in the plane space according to the local neighborhood characteristics of the boundary points, and the boundary points in the plane point set are inversely mapped into the surface point set to obtain boundary contour points of the airfoil skin; Based on the curvature characteristics of the airfoil skin boundary contour points, the airfoil skin boundary contour points are fitted to obtain a B-spline curve, and processing path points are obtained based on the B-spline curve.

2. The method for generating a smooth machining path for a variable curvature airfoil skin robot guided by vision according to claim 1 is characterized in that: The method of converting the three-dimensional point cloud data into a triangular mesh surface by using a point cloud triangulation algorithm includes: The three-dimensional point cloud data is converted into a triangular mesh surface using the Lawson algorithm or the Bowyer-Watson algorithm.

3. The method for generating a smooth machining path for a variable curvature airfoil skin robot guided by vision according to claim 1 is characterized in that: The method of mapping the triangular mesh surface point set to a plane space based on the geodesic distance between any two points on the triangular mesh surface to obtain a corresponding plane point set includes: Based on the geodesic distance between any two points on the triangular mesh surface, a multi-dimensional scaling method is used to map the triangular mesh surface point set into a plane space to obtain a corresponding plane point set.

4. The method for generating a smooth machining path for a variable curvature airfoil skin robot guided by vision according to claim 1 is characterized in that: The step of obtaining the boundary points of the plane point set according to the local neighborhood features of the boundary points in the plane space includes: Traversing a plane point set Each point in , query with the point The nearest k points , choose any point With point Composition vector ; Vector As the benchmark, traverse the remaining points With point Composition vector , and calculate the vector With vector Angle , and calculate the vector With vector If the outer product is positive, then unchanged, if the outer product is negative, then Take its opposite number; Record The maximum value of and minimum value ,like If the angle is smaller than the preset threshold, the point As the boundary points of a plane point set.

5. The method for generating a smooth machining path for a variable curvature airfoil skin robot guided by vision according to claim 1 is characterized in that: The step of fitting the airfoil skin boundary contour points based on the curvature characteristics of the airfoil skin boundary contour points to obtain a B-spline curve comprises: Calculate the parameter value and curvature value corresponding to each airfoil skin boundary contour point; Based on the parameter value and the curvature value, construct a characteristic function reflecting the geometric characteristics of the airfoil skin, and calculate a cumulative distribution function based on the characteristic function; A knot vector is calculated based on the parameter value, and a fitted B-spline curve is obtained based on the cumulative distribution function and the knot vector.

6. The method for generating a smooth machining path for a variable curvature airfoil skin robot guided by vision according to claim 1 or 5, characterized in that: The obtaining of processing path points based on the B-spline curve comprises: The B-spline curve is discretized by using an equal chord length method or an equal residual method to obtain processing path points.

7. The method for generating a smooth machining path for a variable curvature airfoil skin robot guided by vision according to claim 1 is characterized in that: After fitting the airfoil skin boundary contour points based on the curvature characteristics of the airfoil skin boundary contour points to obtain a B-spline curve, and obtaining processing path points based on the B-spline curve, the method further includes: The processing path point position and the corresponding processing posture are converted into the joint angle of the robot at the processing position point based on the robot inverse kinematics.

8. A vision-guided variable curvature airfoil skin robot smoothing processing path generation device, characterized in that: include: An acquisition module is used to acquire three-dimensional point cloud data of the airfoil skin to be processed, pre-process it, and convert the three-dimensional point cloud data into a triangular mesh surface using a point cloud triangular meshing algorithm; A boundary extraction module is used to map a triangular mesh surface point set into a plane space based on the geodesic distance between any two points on the triangular mesh surface to obtain a corresponding plane point set, then obtain boundary points of the plane point set according to local neighborhood features of the boundary points in the plane space, and inversely map the boundary points in the plane point set into the surface point set to obtain boundary contour points of the airfoil skin; A fitting module is used to fit the airfoil skin boundary contour points based on the curvature characteristics of the airfoil skin boundary contour points to obtain a B-spline curve, and obtain processing path points based on the B-spline curve.

9. An electronic device, characterized in that: include: at least one memory for storing a computer program; At least one processor is used to execute the program stored in the memory. When the program stored in the memory is executed, the processor is used to execute the vision-guided variable curvature airfoil skin robot smoothing processing path generation method as described in any one of claims 1-7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program runs on a processor, the processor is enabled to execute the vision-guided variable-curvature airfoil skin robot smoothing processing path generation method as described in any one of claims 1 to 7.

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