Cutter path planning device and method
By constructing the workpiece surface, generating and optimizing tool trajectory lines in CNC machining, and performing tool compensation and machining method control, the problems of low efficiency and large error in tool trajectory planning in the prior art are solved, and efficient and accurate machining effects are achieved.
Patent Information
- Application Number
- CN202510076811.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-17
- Publication Date
- 2025-05-30
AI Technical Summary
In the existing CNC machining technology, tool trajectory planning has the problem of generating dense distribution but much redundancy, which leads to low machining efficiency and ignores the dynamic interaction between tools and workpieces, which is prone to large errors.
By constructing the surface of the machining workpiece, selecting the longest edge as the initial track line, processing the initial track line to obtain the knife contact, and using Gaussian curvature and average curvature to judge the concave and convexity of the curved surface to generate a biased track line. The bias trajectory line is optimized by using neural network model to generate the optimized tool planning trajectory, and tool compensation and machining method control are performed.
It realizes accurate prediction and optimization of tool trajectory planning, improves machining efficiency and machining accuracy, and overcomes the defects that are prone to large errors in the existing technology.
Smart Images
Figure CN120065904A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of numerical control machining, and particularly relates to a tool path planning device and method. Background Art
[0002] In numerical control machining, the quality of the machining program directly affects the machining effect and efficiency of the workpiece. Traditional methods such as manual numerical control programming and program trial cutting verification can no longer meet the rapidly developing industrial requirements.
[0003] In a numerical control system, tool path planning is determined based on various factors such as machining conditions, machining requirements, and workpiece shape; in numerical control programming, tool path planning has always been a core link, directly affecting the quality of the produced workpiece.
[0004] Currently, although some solutions have emerged, in order to ensure machining accuracy, the generated tool paths are densely distributed, with many redundant paths, low machining efficiency, and the dynamic interaction between the tool and the workpiece is ignored, resulting in a defect of large errors. Summary of the Invention
[0005] Aiming at the technical defects mentioned in the background art, the purpose of the embodiments of the present invention is to provide a tool path planning device and method.
[0006] To achieve the above object, in a first aspect, the embodiments of the present invention provide a tool path planning device, including:
[0007] A construction module, configured to construct the surface of the corresponding machined workpiece based on the imported point cloud data;
[0008] A selection module, configured to select the longest edge on the surface and use it as the initial trajectory line;
[0009] A processing module, configured to process the initial trajectory line to obtain tool contact points;
[0010] A judgment module, configured to judge the concavity and convexity of the corresponding surface in the geodesic direction of the tool contact points according to the Gaussian curvature and the mean curvature to obtain a judgment result;
[0011] A generation module, configured to calculate and generate an offset trajectory line in combination with the judgment result and ensure that it is all on the machining surface;
[0012] An optimization module, configured to transmit the generated offset trajectory line to a pre-trained neural network model for optimization processing to obtain an optimized tool planning trajectory.
[0013] As a preferred implementation manner of the present application, the device further includes a compensation module, and the compensation module is used to perform tool compensation based on a preset compensation strategy; wherein, the compensation strategy includes normal compensation of the tool to eliminate the over-cut area.
[0014] As a preferred implementation manner of the present application, the device further includes a control module, and the control module is used to adopt a machining method of removing materials layer by layer along the radial direction during machining to reduce machining deformation.
[0015] As a preferred implementation manner of the present application, the control module is further used to select a tool with a small diameter for machining during machining, and the cutting trajectory is along the length direction of the workpiece.
[0016] As a preferred implementation manner of the present application, the generation module is further used to judge singular points in the offset trajectory line and perform rejection processing on the judged singular points to obtain a smooth tool trajectory.
[0017] In a second aspect, an embodiment of the present invention further provides a tool trajectory planning method, which is applied to a tool trajectory planning device described in the first aspect. The method includes:
[0018] Construct a surface of the corresponding machined workpiece based on the imported point cloud data;
[0019] Select the longest edge on the surface and use it as the initial trajectory line;
[0020] Process the initial trajectory line to obtain tool contact points;
[0021] Judge the concavity and convexity of the corresponding surface in the geodesic direction of the tool contact points according to the Gaussian curvature and the mean curvature to obtain a judgment result;
[0022] Calculate and generate an offset trajectory line in combination with the judgment result, and ensure that it is all on the machining surface;
[0023] Transmit the generated offset trajectory line to a pre-trained neural network model for optimization processing to obtain an optimized tool planning trajectory.
[0024] As a preferred implementation manner of the present application, the method further includes:
[0025] Perform tool compensation based on a preset compensation strategy; wherein, the compensation strategy includes normal compensation of the tool to eliminate the over-cut area.
[0026] As a preferred implementation manner of the present application, the method further includes:
[0027] Adopt a machining method of removing materials layer by layer along the radial direction during machining to reduce machining deformation;
[0028] Select a tool with a small diameter for machining, and the cutting trajectory is along the length direction of the workpiece.
[0029] As a preferred implementation manner of the present application, the method further includes:
[0030] Judge singular points in the offset trajectory line, and perform elimination processing on the judged singular points to obtain a smooth tool trajectory.
[0031] The technical solution provided by the embodiment of the present invention optimizes the generated offset trajectory line by introducing a neural network model, realizes accurate prediction and optimization in tool trajectory planning, and finds the optimal solution after analyzing a large number of path and parameter combinations, thereby improving the machining efficiency and machining accuracy; at the same time, considering the dynamic interaction between the tool and the workpiece during machining, corresponding tool compensation and control of the machining method and trajectory are performed, thereby overcoming the defect of large errors that easily occur in the prior art. Description of the Drawings
[0032] In order to more clearly illustrate the specific implementation manners of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific implementation manners or the prior art.
[0033] Figure 1 is a principle block diagram of a tool trajectory planning device provided by an embodiment of the present invention;
[0034] Figure 2 is a flowchart of a tool trajectory planning method provided by an embodiment of the present invention. Detailed Implementation Manner
[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0036] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.
[0037] Throughout the specification, references to "one embodiment", "an embodiment", "one example" or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, the phrases "in one embodiment", "in an embodiment", "one example" or "an example" appearing throughout the specification do not necessarily all refer to the same embodiment or example. Additionally, the particular features, structures, or characteristics may be combined in any suitable combination and / or sub-combination in one or more embodiments or examples.
[0038] It should be noted that, unless otherwise specified, the technical terms in this embodiment have the ordinary meanings understood by those skilled in the art.
[0039] Please refer to Figure 1 , a tool path planning device provided by an embodiment of the present invention includes:
[0040] A construction module for constructing the surface of the corresponding workpiece to be machined based on the imported point cloud data;
[0041] A selection module for selecting the longest edge on the surface and using it as the initial trajectory line;
[0042] A processing module for processing the initial trajectory line to obtain tool contact points;
[0043] A judgment module for judging the concavity and convexity of the corresponding surface in the geodesic direction of the tool contact points according to the Gaussian curvature and the mean curvature to obtain a judgment result;
[0044] A generation module for calculating and generating an offset trajectory line in combination with the judgment result and ensuring that it is all on the machining surface;
[0045] An optimization module for transmitting the generated offset trajectory line to a pre-trained neural network model for optimization processing to obtain an optimized tool planning trajectory.
[0046] In this embodiment, by importing the point cloud data of the surface, using points to form lines, and then using lines to form surfaces, the generation of the fitting surface is realized;
[0047] The point where the tool edge is tangent to the machining surface is called the tool contact point;
[0048] During the generation of the initial trajectory line, a curve with an overall change in the curvature of the corresponding surface in the geodesic direction of the tool contact points less than a set threshold can also be selected and used as the initial trajectory line;
[0049] By implementing the discrete processing of the initial trajectory line, the obtained discrete points are the tool contact points; in this embodiment, the equal-angle discretization method can be used to achieve uniform C-axis movement, effectively solving the drawbacks of equal-arc-length discretization.
[0050] During application, judge according to the concavity and convexity of the surface; that is, judge the type of points on the surface according to the positive and negative of the two. In addition, since the surface is in a continuously changing state, the type corresponding to the local area of the surface around the point can be determined. Among them, the types include plane, ellipsoid surface, hyperboloid surface, etc.
[0051] Calculate in combination with the judgment result, mainly including calculating the machining feed rate and determining the position of the tool contact point. Among them, the feed rate calculation can be based on the existing method; the coordinates of the offset tool contact point are obtained according to the surface expression, the geodesic direction, and the machining feed rate.
[0052] It should be noted that the neural network model combines the historical machining database and uses the training neural network to learn the rules and patterns of the machining process, so as to generate the optimal tool path. The neural network algorithm can automatically adapt to different part shapes and machining requirements, and can greatly shorten the time for algorithm optimization.
[0053] Furthermore, the device further includes a compensation module, and the compensation module is used to perform tool compensation based on a preset compensation strategy. Among them, the compensation strategy includes the normal compensation of the tool to eliminate the overcut area.
[0054] The specific normal compensation is as follows:
[0055] Generate discrete tool contact points of the complex surface by the equal-angle discretization method, and divide the generated tool contact points on nL intersection lines passing through the center of the surface, where nL = 360 / Δθ, and Δθ is the discrete angle; this intersection line is the intersection line of the workpiece and the cutting plane.
[0056] Solve the tangent vector tp at point P from the intersection line, and then solve the unit vector np from the geometric relationship np·tp = 0. Among them, n is the normal vector of the surface at the tool contact point P; np is the projection of the normal vector on the cutting plane; tp is the tangent vector of the tool contact point P at the intersection line.
[0057] Finally, the coordinates of the tool position point under normal compensation are obtained as: P + np·Rt; Rt is the tool nose radius. Thus, the accuracy of the required tool position point is relatively high, the overcut area can be effectively eliminated, and it is ensured that the tool edge is tangent to the intersection line at a point P.
[0058] During application, the rake angle of the tool can also be determined in combination with the maximum and minimum curvatures at the tool contact point P, the maximum and minimum curvatures of the tool surface, and the radius.
[0059] Furthermore, in another embodiment, due to the easy occurrence of cutting vibration and elastic deformation during machining, it is impossible to ensure the dimensional accuracy and surface quality of the workpiece, which affects the machining efficiency and manufacturing cost of the workpiece. During the material removal process, due to the action of factors such as cutting force and cutting heat, the problem of easy machining deformation is extremely likely to occur.
[0060] The device further includes a control module, which is used to adopt a machining method of removing materials layer by layer along the radial direction during machining to reduce machining deformation.
[0061] At the same time, due to the uneven and large allowance removal during the cutting process of the workpiece, the cutting stress inside the workpiece is constantly changing and recombining, resulting in workpiece deformation. At the same time, the cutting component force of the tool causes unevenness on the workpiece surface after elastic recovery, resulting in machining wall thickness error; the control module is also used to select a small-diameter tool for machining during machining, and the cutting trajectory is along the length direction of the workpiece; thus forming trajectories including cycloid, arc, sine, cosine, etc.
[0062] By using a small-diameter tool, its cutting component force is small, and the machining wall thickness error is small after the elastic recovery of the workpiece surface; and the length direction adopted is convenient for uniformly releasing the stress of the workpiece.
[0063] Furthermore, the generation module is also used to judge the singular points in the offset trajectory line and perform elimination processing on the judged singular points to obtain a smooth tool trajectory.
[0064] In this embodiment, in order to make the generated trajectory transition smoothly and be smooth and continuous; during judgment, distance judgment and angle judgment are performed based on the tool contact points to be judged; if any judgment exceeds the corresponding threshold, it is judged as a local fluctuation point and needs to be eliminated.
[0065] The above solution optimizes the generated offset trajectory line by introducing a neural network model, realizes accurate prediction and optimization in tool path planning, and finds the optimal solution after analyzing a large number of paths and parameter combinations, thereby improving machining efficiency and machining accuracy; at the same time, considering the dynamic interaction between the tool and the workpiece during machining, corresponding tool compensation and control of machining methods and trajectories are performed, thereby overcoming the defect of easy occurrence of large errors in the prior art.
[0066] Refer to Figure 2 , based on the same inventive concept, the embodiment of the present invention also provides a tool path planning method, which is applied to a tool path planning device described in the first aspect. The method includes the following steps:
[0067] S101, construct the surface of the corresponding machined workpiece based on the imported point cloud data;
[0068] S102. Select the longest edge on the surface and use it as the initial trajectory line; and process the initial trajectory line to obtain the tool contact points.
[0069] S103. Judge the concavity and convexity of the corresponding surface in the geodesic direction of the tool contact points according to the Gaussian curvature and the mean curvature to obtain a judgment result.
[0070] S104. Calculate and generate an offset trajectory line in combination with the judgment result, and ensure that it is all on the machining surface.
[0071] S105. Transmit the generated offset trajectory line to a pre-trained neural network model for optimization processing to obtain an optimized tool path trajectory.
[0072] Furthermore, the method further includes:
[0073] Perform tool compensation based on a preset compensation strategy; wherein, the compensation strategy includes normal compensation of the tool to eliminate the over-cut area.
[0074] The method further includes:
[0075] Adopt a machining method of removing materials layer by layer along the radial direction during machining to reduce machining deformation.
[0076] Select a tool with a small diameter for machining, and the cutting trajectory is along the length direction of the workpiece.
[0077] In this embodiment, to make the generated trajectory transition smoothly and be smooth and continuous; the method further includes:
[0078] Judge the singular points in the offset trajectory line and perform elimination processing on the judged singular points to obtain a smooth tool trajectory.
[0079] It should be noted that for a more specific description of the working process of the method embodiment, please refer to the foregoing device embodiment part, which will not be elaborated here.
[0080] In the whole solution, by introducing a neural network model to optimize the generated offset trajectory line, accurate prediction and optimization are realized in tool path planning. After analyzing a large number of path and parameter combinations, the optimal solution is found, thereby improving the machining efficiency and machining accuracy; at the same time, considering the dynamic interaction between the tool and the workpiece during machining, corresponding tool compensation and control of the machining method and trajectory are carried out, thereby overcoming the defect of large errors that easily occur in the prior art.
[0081] In the embodiments provided in this application, it should be understood that the disclosed device can also be implemented in other ways. The device embodiments described above are merely illustrative. It should also be noted that in some alternative implementations, the functions marked in the boxes may occur in a different order than that marked in the drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, as well as the combination of boxes in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.
[0082] In addition, in each embodiment of the present invention, the functional modules can be integrated together to form an independent part, or each module can exist alone, or two or more modules can be integrated to form an independent part.
[0083] If the above functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing 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 methods described in each embodiment of the present invention. It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
[0084] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.
Claims
1. A tool path planning device, characterized in that: include: A construction module is used to construct the surface of the corresponding workpiece based on the imported point cloud data; A selection module, used for selecting the longest edge on the surface and using it as an initial trajectory line; A processing module, used for processing the initial trajectory line to obtain a knife contact point; A judgment module is used to judge the concavity and convexity of the corresponding surface in the short-range line direction of the tool contact point according to the Gaussian curvature and the average curvature to obtain a judgment result; A generation module, used to calculate and generate offset trajectory lines based on the judgment results, and ensure that they are all on the processing surface; The optimization module is used to transmit the generated offset trajectory line to the pre-trained neural network model for optimization processing to obtain the optimized tool planning trajectory.
2. A tool path planning device as claimed in claim 1, characterized in that: The device also includes a compensation module, which is used to perform tool compensation based on a preset compensation strategy; wherein the compensation strategy includes normal compensation of the tool to eliminate overcut areas.
3. A tool path planning device as claimed in claim 2, characterized in that: The device also includes a control module, which is used to adopt a processing method of removing materials layer by layer along the radial direction during processing to reduce processing deformation.
4. A tool path planning device as claimed in claim 3, characterized in that: The control module is also used to select a small diameter tool for machining, and the cutting trajectory is along the length direction of the workpiece.
5. A tool path planning device according to any one of claims 1 to 4, characterized in that: The generating module is further used to judge the singular points in the offset trajectory line and remove the judged singular points to obtain a smooth tool trajectory.
6. A tool path planning method, characterized in that: A tool path planning device according to claim 1, wherein the method comprises: Construct the surface of the corresponding workpiece based on the imported point cloud data; Select the longest edge on the surface and use it as the initial trajectory line; Processing the initial trajectory line to obtain a knife contact point; The concavity and convexity of the corresponding surface in the short-range line direction of the tool contact point are judged according to the Gaussian curvature and the average curvature to obtain the judgment result; Calculate and generate offset trajectory lines based on the judgment results, and ensure that they are all on the processing surface; The generated offset trajectory is transmitted to the pre-trained neural network model for optimization processing to obtain the optimized tool planning trajectory.
7. A tool path planning method as claimed in claim 6, characterized in that: The method further comprises: Tool compensation is performed based on a preset compensation strategy; wherein the compensation strategy includes normal compensation of the tool to eliminate overcut areas.
8. A tool path planning method as claimed in claim 6 or 7, characterized in that: The method further comprises: During processing, the material is removed layer by layer along the radial direction to reduce processing deformation; Use small diameter tools for machining, and the cutting trajectory is along the length of the workpiece.
9. A tool path planning method as claimed in claim 8, characterized in that: The method further comprises: Singular points are judged in the offset trajectory, and the judged singular points are eliminated to obtain a smooth tool trajectory.