Curve shape follow-up compensation processing method based on on-machine measurement and storage medium

Abstract

The invention relates to the technical field of numerical control machining, and discloses a curve shape follow-up compensation machining method based on on-machine measurement and a storage medium, and the method comprises the steps: planning theoretical measurement points on an adjacent surface of a to-be-compensated curve on a to-be-machined workpiece model, forming an on-machine measurement path, and obtaining an actual measurement point corresponding to each theoretical measurement point; projecting all theoretical measurement points to the parameterized to-be-compensated curve to obtain corresponding theoretical parameters; calculating an error value between each theoretical measurement point and the corresponding actual measurement point; obtaining a cutting touch parameter corresponding to a cutting touch point corresponding to each cutter location point, a theoretical parameter and a corresponding error value, and obtaining a cutting touch error of each cutting touch point by utilizing linear interpolation; and calculating a corresponding error vector based on the cutting contact error and the cutting contact normal to obtain a corresponding actual cutting contact, and further obtaining an actual tool nose point at each tool location point to form a compensation tool path for performing curve conformal compensation on a to-be-compensated curve of the to-be-processed workpiece.

Description

Technical Field

[0001] The invention relates to the technical field of numerical control machining, and in particular to a curve conformal compensation machining method based on on-machine measurement and a storage medium. Background Art

[0002] During the machining or forming process, some parts will be deformed due to the influence of cutting force and initial residual stress, resulting in a difference between the part curve shape and the theoretical model curve contour shape, causing the theoretical machining program to no longer be applicable to the machining of the current part. If the theoretical machining program is continued for machining, it may cause overcutting or undercutting of the part, thus failing to meet the part machining requirements; refer to Figure 1 As shown in Figure 1, it is a schematic diagram of the deformation of the machining curve. Therefore, it is necessary to adjust the theoretical machining program to ensure that the accuracy of the produced workpiece meets the actual requirements.

[0003] Because the curve feature of a part is generally the intersection line of two surfaces, it is difficult to directly obtain the shape of the part. The more commonly used technical solution is: directly plan the measurement points for offline detection on the deformed part contour line; then calculate the actual points based on the measurement point deviation, and use the actual points to fit the spline curve; obtain the deviation of each processing point from the spline curve, and compensate the deviation value to the tool path.

[0004] The existing scheme is based on direct measurement of the curve contour position to perform subsequent compensation processing. However, for the edges of the workpiece, direct measurement after deformation may result in missing or failure to detect, and it is impossible to directly use the method of fitting the spline curve of the actual point to calculate the compensation tool path. As a result, it is impossible to accurately measure the deformation of the edge, making it difficult to control the quality of the processed parts, reducing the production and processing efficiency. Summary of the invention

[0005] To this end, the technical problem to be solved by the present invention is to overcome the problem that the prior art cannot directly measure the deformed workpiece when performing curve compensation, and thus cannot perform subsequent fitting, resulting in poor processing accuracy and low efficiency.

[0006] In order to solve the above technical problems, the present invention provides a curve-conforming compensation processing method based on on-machine measurement, comprising: Model the workpiece to be processed, and obtain the curve to be compensated based on the model of the workpiece to be processed; discretize the curve to be compensated, generate multiple original sampling points as theoretical measurement points of the adjacent surface of the curve to be compensated, and form an on-machine measurement path; The measuring head is made to move along the on-machine measuring path to obtain the actual measuring point corresponding to each theoretical measuring point; Parameterize the curve to be compensated, and obtain the parameterized curve to be compensated; Project all theoretical measurement points onto the parameterized curve to be compensated to obtain the theoretical parameters corresponding to each theoretical measurement point; Calculate the difference vector between the coordinates of each theoretical measurement point and the coordinates of the corresponding actual measurement point, and use the projection distance of the difference vector in the theoretical normal direction as the error value between each theoretical measurement point and the corresponding actual measurement point; Acquire multiple tool position points on the machine measurement path, subtract the tool radius from the tool position point along the tool axis direction to obtain the corresponding theoretical tool center; project the multiple theoretical tool centers onto the parameterized curve to be compensated to obtain the cutting contact point corresponding to each tool position point; project each cutting contact point onto the parameterized curve to be compensated to obtain the cutting contact parameter corresponding to each cutting contact point; Based on the contact parameters of each contact point, as well as the theoretical parameters on the parameterized compensation curve and the corresponding error values, a linear interpolation method is used to obtain the contact error corresponding to each contact point; Based on the contact point normal and contact error of each contact point, an error vector corresponding to each contact point is obtained; after each contact point is moved according to the error vector, a corresponding actual contact point is obtained; Based on the actual cutting contact point and the tool radius, the actual tool tip point at each tool position point is obtained to form a compensation tool path for performing curve-conforming compensation on the to-be-compensated curve of the workpiece to be processed.

[0007] Preferably, the method for discretizing the curve to be compensated includes adaptive discretization and arc-length-chord-height mixed constraint discretization.

[0008] Preferably, parameterizing the curve to be compensated to obtain the parameterized curve to be compensated includes: Based on the preset initial parameters and the length of each curve segment in the curve to be compensated, the first curve segment in the curve to be compensated is calculated. The starting point parameters corresponding to the curve segment , expressed as: , , Indicates the total number of curve segments in the curve to be compensated; The first Any point on the curve segment Parameters , expressed as: ; in, is the preset initial parameter, indicating the starting point parameter corresponding to the first curve segment in the curve to be compensated; Indicates The length of the curve segment; Indicates The starting point of the curve segment to The curve length at the point.

[0009] Preferably, the curve to be compensated includes a plane curve and a space curve; If the curve to be compensated is a plane curve, the original sampling points are arranged on a single adjacent surface as theoretical measured points, and the actual measured points are obtained by on-machine measurement; If the curve to be compensated is a space curve, theoretical measurement points are arranged on the left adjacent surface and the right adjacent surface of the space curve respectively, and the actual measurement points on the left and the right are obtained by on-machine measurement.

[0010] Preferably, based on the contact parameters of each contact point, and the theoretical parameters on the parameterized compensation curve and the corresponding error values, a linear interpolation method is used to obtain the contact error corresponding to each contact point, which is expressed as: ; in, Indicates The contact error corresponding to each contact point is: and Respectively represent The theoretical measuring point adjacent to the left side of the contact point The theoretical measurement point adjacent to the right Theoretical parameters of Indicates The theoretical measuring point adjacent to the left side of the contact point The error value between the actual measurement point and its corresponding value is Indicates The theoretical measuring point adjacent to the right side of the contact point The error value between the actual measurement point and its corresponding value.

[0011] Preferably, based on the contact point normal and the contact error of each contact point, obtaining the error vector corresponding to each contact point includes: When the curve to be compensated is a plane curve, the product of the contact point normal of each contact point and the contact error is taken as the error vector corresponding to each contact point; When the curve to be compensated is a spatial curve, on both the left adjacent surface and the right adjacent surface, the method includes: obtaining an isoparametric line on the adjacent surface based on the contact error and contact parameter of each contact point; offsetting the isoparametric line with the normal direction of the adjacent surface as the direction and the contact error as the length to obtain a corresponding offset line; Obtain the intersection point of the offset lines of the left adjacent face and the right adjacent face as the offset intersection point; A vector pointing from the cut contact point to the offset intersection point is obtained as the error vector corresponding to the cut contact point.

[0012] Preferably, when the curve to be compensated is a plane curve, the product of the contact point normal of each contact point and the contact error is used as the error vector corresponding to each contact point: ; in, Indicates The error vector of the contact point, Indicates The tangent contact normal of a tangent contact point, Indicates The contact error corresponding to each contact point.

[0013] Preferably, a vector pointing from the cut contact point to the offset intersection point is obtained as the error vector corresponding to the cut contact point, which is expressed as: ; in, Indicates The error vector of the contact point is Indicates A cutting contact point, Indicates the offset intersection point.

[0014] Preferably, based on the actual cutting contact point and the tool radius, the actual tool tip point at each tool position point is obtained to form a compensation tool path for performing curve-conforming compensation on the to-be-compensated curve of the workpiece to be processed, including: The actual cutting contact point is offset along the normal direction of the cutting contact point by a distance of the tool radius to obtain the actual tool center; The actual tool center is offset in the opposite direction of the tool axis by a tool radius to obtain the actual tool position point; Based on the actual tool tip points corresponding to all tool position points, a compensation tool path is formed to perform curve-conforming compensation on the to-be-compensated curve of the workpiece to be processed.

[0015] This embodiment further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the curve-conforming compensation processing method based on on-machine measurement as described above are implemented.

[0016] The above technical solution of the present invention has the following beneficial effects compared with the prior art: The curve conformal compensation processing method based on on-machine measurement described in the present invention uses the adjacent surface of the curve to be compensated to measure the edge represented by the curve to be compensated, plans multiple theoretical measurement points, and generates an on-machine measurement path; based on the on-machine measurement path, obtains the corresponding actual measurement points, and calculates the error value between the actual measurement points and the theoretical measurement points; at the same time, the curve to be compensated is parameterized, and on the parameterized curve to be compensated, a linear interpolation method is used to obtain the contact error of each contact point on the on-machine measurement path, and then based on the contact error, an error vector is obtained, the contact point is moved, the actual contact point and its corresponding actual tool tip point are obtained, and a compensation tool path is formed to compensate the curve to be compensated. The present invention calculates the actual tool tip point of each contact point based on the theoretical measurement point on the curve to be compensated, so that the generated compensation tool path can be closely combined with the actual shape change of the curve to be compensated, and the corresponding moving direction and distance of the contact point are determined according to the contact error at different positions on the curve to be compensated, which effectively improves the compensation accuracy. Moreover, the present invention only needs one measurement and compensation to accurately adapt to the shape change of the curve to be compensated, effectively improves the compensation processing efficiency, and reduces the number of repeated debugging during the processing.

[0017] The curves to be compensated in the present invention include plane curves and space curves. For plane curves, a single adjacent surface is used to plan measurement points; for space curves, two left and right adjacent surfaces are used to plan measurement points. The present invention selects different methods for measuring point planning for different types of curves, which fully conforms to the geometric characteristics of different types of curves, avoids unnecessary complex measurement operations on plane curves, improves measurement efficiency, and ensures that sufficiently comprehensive and multi-angle measurement data can be obtained for complex geometric objects such as space curves, which helps to improve compensation accuracy and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 It is a schematic diagram of the deformation of the processing curve; Figure 2 It is a flow chart of the steps of the curve conformal compensation processing method based on on-machine measurement provided by the present invention; Figure 3 is a schematic diagram of a parameterized curve; Figure 4 It is a schematic diagram for planning measurement points of adjacent surfaces of plane curves; Figure 5 It is a schematic diagram for planning measurement points of adjacent surfaces of space curves; Figure 6 This is a schematic diagram of the principle of calculating the error value of the measuring point; Figure 7 It is a schematic diagram of the projection of the measuring point onto the curve to be compensated; Figure 8 It is a schematic diagram of the contact points and measuring points of the plane curve; Fig. 9 It is a schematic diagram of the contact points and measurement points of the space curve; Fig.10 It is a schematic diagram of the contact point offset of the plane curve; Fig.11 It is a schematic diagram of the contact point offset of the space curve; Fig.12 This is a schematic diagram of theoretical tool path adjustment; Fig.13 This is the flow chart of the spatial surface conformal compensation processing; Fig.14 This is a schematic diagram of the tangent contact projection. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0020] Reference Figure 2 As shown, the step flow chart of the curve conformal compensation processing method based on on-machine measurement provided by the present invention includes the following steps: S101: Modeling the workpiece to be processed, and obtaining the curve to be compensated based on the model of the workpiece to be processed; discretizing the curve to be compensated, generating multiple original sampling points as theoretical measurement points of the adjacent surface of the curve to be compensated, and forming an on-machine measurement path; S102: The measuring head moves along the on-machine measuring path to obtain the actual measuring point corresponding to each theoretical measuring point; S103: Parameterize the curve to be compensated, and obtain the parameterized curve to be compensated, which is expressed as: Based on the preset initial parameters and the length of each curve segment in the curve to be compensated, the first curve segment in the curve to be compensated is calculated. The starting point parameters corresponding to the curve segment , expressed as: , , Indicates the total number of curve segments in the curve to be compensated; The first Any point on the curve segment Parameters , expressed as: ; in, is the preset initial parameter, indicating the starting point parameter corresponding to the first curve segment in the curve to be compensated; Indicates The length of the curve segment; Indicates The starting point of the curve segment to The curve length at the point.

[0021] S104: Projecting all theoretical measurement points onto the parameterized curve to be compensated to obtain theoretical parameters corresponding to each theoretical measurement point; S105: Calculate the difference vector between the coordinates of each theoretical measurement point and the coordinates of the corresponding actual measurement point, and use the projection distance of the difference vector in the theoretical normal direction as the error value between each theoretical measurement point and the corresponding actual measurement point; S106: Acquire multiple tool position points on the machine measurement path, subtract the tool radius from the tool position point along the tool axis direction to acquire the corresponding theoretical tool center; project the multiple theoretical tool centers onto the parameterized curve to be compensated to acquire the contact point corresponding to each tool position point; project each contact point onto the parameterized curve to be compensated to acquire the contact parameter corresponding to each contact point; S107: Based on the contact parameters of each contact point, and the theoretical parameters on the parameterized compensation curve and the corresponding error values, a contact error corresponding to each contact point is obtained by using a linear interpolation method, which is expressed as: ; in, Indicates The contact error corresponding to each contact point is: and Respectively represent The theoretical measuring point adjacent to the left side of the contact point The theoretical measurement point adjacent to the right Theoretical parameters of Indicates The theoretical measuring point adjacent to the left side of the contact point The error value between the actual measurement point and its corresponding value is Indicates The theoretical measuring point adjacent to the right side of the contact point The error value between the actual measurement point and its corresponding value.

[0022] S108: based on the contact point normal and contact error of each contact point, obtaining an error vector corresponding to each contact point; after moving each contact point according to the error vector, obtaining a corresponding actual contact point; S109: Based on the actual cutting contact point and the tool radius, the actual tool tip point at each tool position point is obtained to form a compensation tool path for performing curve-conforming compensation on the to-be-compensated curve of the workpiece to be processed, including: The actual contact point is offset along the normal direction of the contact point by a distance of a tool radius to obtain the actual tool center; the actual tool center is offset along the opposite direction of the tool axis by a distance of a tool radius to obtain the actual tool position point; based on the actual tool tip points corresponding to all tool position points, a compensation tool path is formed to perform curve-conforming compensation on the curve to be compensated of the workpiece to be processed.

[0023] Specifically, after the compensation tool path of the curve to be compensated in the workpiece model to be processed is obtained in the modeling software, it is sent to the control center of the machine tool to control the tool of the machine tool to perform compensation processing according to the compensation tool path to realize curve conformal compensation.

[0024] Specifically, the method for discretizing the curve to be compensated includes adaptive discretization and arc-length-chord-height mixed constraint discretization.

[0025] Specifically, the curve to be compensated includes a plane curve and a space curve; If the curve to be compensated is a plane curve, the original sampling points are arranged on a single adjacent surface as theoretical measured points, and the actual measured points are obtained by on-machine measurement; If the curve to be compensated is a space curve, theoretical measurement points are arranged on the left adjacent surface and the right adjacent surface of the space curve respectively, and the actual measurement points on the left and the right are obtained by on-machine measurement.

[0026] ① When the curve to be compensated is a plane curve, the product of the contact point normal of each contact point and the contact error is used as the error vector corresponding to each contact point, expressed as: ; in, Indicates The error vector of the contact point, Indicates The tangent contact normal of a tangent contact point, Indicates The contact error corresponding to each contact point.

[0027] ② When the curve to be compensated is a spatial curve, on both the left adjacent surface and the right adjacent surface, the following steps are performed: based on the contact error and contact parameter of each contact point, an isoparametric line is obtained on the adjacent surface; with the normal direction of the adjacent surface as the direction and the contact error as the length, the isoparametric line is offset to obtain a corresponding offset line; Obtain the intersection point of the offset lines of the left adjacent face and the right adjacent face as the offset intersection point; Get the vector from the cut contact point to the offset intersection point as the error vector corresponding to the cut contact point, expressed as: ; in, Indicates The error vector of the contact point is Indicates A cutting contact point, Indicates the offset intersection point.

[0028] The curves to be compensated in the present invention include plane curves and space curves. For plane curves, a single adjacent surface is used to plan measurement points; for space curves, two left and right adjacent surfaces are used to plan measurement points. The present invention selects different methods for measuring point planning for different types of curves, which fully conforms to the geometric characteristics of different types of curves, avoids unnecessary complex measurement operations on plane curves, improves measurement efficiency, and ensures that sufficiently comprehensive and multi-angle measurement data can be obtained for complex geometric objects such as space curves, which helps to improve compensation accuracy and efficiency.

[0029] Based on the above embodiment, in the embodiment of the present invention, the error between the measured point and the theoretical point is calculated by indirectly measuring the adjacent surface, and the error value of any tool contact point is calculated according to the error value of the limited measurement position and the compensation curve after parameterization. Finally, the theoretical processing program is corrected according to the error value and the different curve types, which specifically includes: S201: In actual situations, the compensation curve may be composed of multiple curve segments, so the curve needs to be "parameterized" before linear interpolation can be used for calculation. Figure 3 As shown in the figure, it is a schematic diagram of a parameterized curve; let the starting point parameter of the first line of the curve group be , then the parameters of the starting point of the second line are (in is the length of the first line segment), and so on, the starting point parameter of the last line segment , , Indicates the total number of curve segments in the curve to be compensated; Any point The parameters are: ; in, is the preset initial parameter, indicating the starting point parameter corresponding to the first curve segment in the curve to be compensated; Indicates The length of the curve segment; Indicates The starting point of the curve segment to The curve length at the point.

[0030] S202: After parameterizing the compensation curve, calculate the error between the measurement point and the actual measurement point, and Project onto the parameterized curve to get the corresponding parameters , and use the error of the measurement point as the compensation curve The error value at ; Generate measurement points on the adjacent surface of the curve according to the adaptive discrete or arc-length-chord-height mixed constraint discrete curve, and generate the on-machine measurement path. Assume that n theoretical measurement points are generated discretely, then generate the measurement NC program, and measure in the machine tool. After the measurement, obtain the actual measurement point coordinates; refer to Figure 4 The following is a schematic diagram of the measurement point planning of the adjacent surface of the plane curve; Figure 5 As shown, it is a schematic diagram of planning measurement points of adjacent surfaces of space curves; Reference Figure 6 As shown in the figure, it is a schematic diagram of the error value calculation principle of the measuring point. Since the normal direction of the measuring point may not coincide with the normal direction of the measured point, the difference between the measured coordinates and the coordinates of the theoretical point, the projection distance on the theoretical normal direction, is used as the shape error value of the point. The error of each point is calculated in turn to obtain the error measurement results of these n points.

[0031] Reference Figure 7 As shown, it is a schematic diagram of the projection of the measuring point onto the curve to be compensated; S203: Project the tool position point onto the compensation curve to obtain parameters , through linear interpolation, the knife contact error is estimated and expressed as: ; The theoretical tool path is composed of a large number of tool positions and tool axes. The tool position is subtracted from the tool radius along the tool axis to obtain the theoretical tool center. The theoretical tool center is projected onto the parameterized compensation curve to obtain the cutting contact point and the corresponding parameters of the point. ; Due to indirect measurement and limited measuring points, there is no one-to-one correspondence between the measuring points and the tool position points, so it is necessary to The contact point error is calculated by linear interpolation with the completed measurement point error.

[0032] Reference Figure 8 As shown in the figure, it is a schematic diagram of the contact points and measurement points of a plane curve. For a plane curve, there is only a measurement point on one side, so only one error value needs to be calculated. . Reference Fig. 9 As shown in the figure, it is a schematic diagram of the contact point and measurement point of the space curve. For the space curve, there are two sets of measurement points on the left and right adjacent surfaces. The left error of the contact point needs to be calculated according to the left measurement points and the right measurement points respectively. The error with the right side .

[0033] ① Plane curve compensation: Reference Fig.10 , is a schematic diagram of the contact point offset of the plane curve; Calculate the tool contact point error, shift the theoretical tool contact point along the tool contact point normal by the error value, and obtain the actual tool contact point; where the translation vector is: ; represents the normal direction of the theoretical tangent contact point, Indicates the error at this point; ②Spatial curve compensation: Reference Fig.11 , is a schematic diagram of the contact point offset of the space curve; The calculation of space curve error needs to consider the errors of the left and right adjacent surfaces at the same time. It is stipulated that when observing from the direction of the space curve, the left side is the left adjacent surface, and the right side is the right adjacent surface; The linear interpolation method is used to calculate the left adjacent surface error: , the error of the right adjacent surface is ; Get the parameters of the contact point on the left and right adjacent surfaces , ;according to , Calculate the corresponding left adjacent surface isoparametric lines respectively Isoparametric line with right adjacent face ; The two isoparametric lines are respectively offset according to the normal of the adjacent surface corresponding to the error and , get two bias lines and ; Get two bias lines and Intersection ; Calculate the error vector, expressed as: ; S204: Theoretical tool path adjustment: Reference Fig.12 As shown, it is a schematic diagram of theoretical tool path adjustment; The theoretical contact point is translated along the error vector to obtain the actual contact point; The actual cutting contact point is offset along the normal direction of the cutting contact point by a tool radius to obtain the actual tool center; The actual tool center is offset by a tool radius in the opposite direction of the tool axis to obtain the actual tool tip point; By reassembling the actual tool tip point and tool axis, the adjusted tool path can be obtained.

[0034] Based on the above embodiments, the curve compensation processing technology of the present invention selects different methods for measuring point planning according to different curve types through on-machine measurement means. Since the edges cannot be measured directly, an indirect measurement method is adopted. The plane curve adopts a single adjacent surface to plan the measuring points, and the space curve adopts the left and right adjacent surfaces to plan the measuring points. The actual position is obtained by performing on-machine measurement, and the shape error of the measuring point is calculated by using the actual position and the theoretical position. Through a limited number of measurement data, the error estimation method is used to calculate the error of any tool contact point. Finally, according to the actual error of each tool position point, the theoretical program is adjusted to the actual processing program, and the actual processing program is used for processing. In addition, this embodiment uses computer language to implement the above steps in software, solidifies the automated program of curve conformal compensation processing, and only needs to plan the measuring points on the part surface in the software and generate the measurement program to realize the in-machine measurement and automatically and quickly calculate the compensation amount, complete the modification of the processing program, and realize curve compensation more directly and efficiently, which can significantly improve the processing efficiency of parts.

[0035] This embodiment further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the curve-conforming compensation processing method based on on-machine measurement as described above are implemented.

[0036] Based on the above embodiments, the embodiment of the present invention uses the curve conformal compensation processing method based on on-machine measurement provided by the present invention to perform spatial surface conformal compensation processing, referring to Fig.13 The figure shows the flow chart of spatial surface conformal compensation processing, and the specific steps include: (1) Plan measurement points and calculate measurement errors: According to the curve type, plan several measurement points on the adjacent surface, generate an on-machine measurement path, and then generate a measurement NC program and send it to the machine tool for on-machine measurement to obtain the error between these measured coordinates and the theoretical coordinates.

[0037] Take two consecutive measuring points on the left and right adjacent surfaces as an example, assuming that the angle between the left and right adjacent surfaces is 135 degrees, assuming that the error value E1 of P1 is 0.20mm, the corresponding curve parameter is 1, assuming that the error value E2 of P2 is 0.13mm, the corresponding curve parameter is 2; assuming that the error value E3 of P3 is 0.19mm, the corresponding curve parameter is 1, assuming that the error value E4 of P4 is 0.24mm, the corresponding curve parameter is 2; (2) Project the tool path and calculate the error value of the cutting contact point: Reference Fig.14 The figure shows the projection diagram of the contact point; the contact point P t Project the parameterized curve to obtain the corresponding parameters; then, based on the measurement error data of the left and right adjacent surfaces, use linear interpolation to calculate the knife contact error. In this embodiment, the knife contact projection parameter is 1.5. The following is the calculation of the left and right adjacent surface errors El and E r ; ; ; According to the error calculation, press E l and E r Offset the isoparametric lines of the left and right adjacent faces and find the intersection point P act , then the error vector is: ; (3) Theoretical tool path adjustment: First, translate the contact point Get the actual cutting contact point, then offset the actual cutting contact point along the normal direction of the cutting contact point by a tool radius to get the actual tool center, and finally offset the actual tool center by a tool radius in the opposite direction of the tool axis to get the actual tool tip point. Reassemble the actual tool tip point and the tool axis to get the adjusted tool path.

[0038] (4) The above steps are implemented in software form using computer language to create an automated program for surface conformal compensation processing.

[0039] The curve conformal compensation processing method based on on-machine measurement described in the present invention uses the adjacent surface of the curve to be compensated to measure the edge represented by the curve to be compensated, plans multiple theoretical measurement points, and generates an on-machine measurement path; based on the on-machine measurement path, obtains the corresponding actual measurement points, and calculates the error value between the actual measurement points and the theoretical measurement points; at the same time, the curve to be compensated is parameterized, and on the parameterized curve to be compensated, a linear interpolation method is used to obtain the contact error of each contact point on the on-machine measurement path, and then based on the contact error, an error vector is obtained, the contact point is moved, the actual contact point and its corresponding actual tool tip point are obtained, and a compensation tool path is formed to compensate the curve to be compensated. The present invention calculates the actual tool tip point of each contact point based on the theoretical measurement point on the curve to be compensated, so that the generated compensation tool path can be closely combined with the actual shape change of the curve to be compensated, and the corresponding moving direction and distance of the contact point are determined according to the contact error at different positions on the curve to be compensated, which effectively improves the compensation accuracy. Moreover, the present invention only needs one measurement and compensation to accurately adapt to the shape change of the curve to be compensated, effectively improves the compensation processing efficiency, and reduces the number of repeated debugging during the processing. The curves to be compensated in the present invention include plane curves and space curves. For plane curves, a single adjacent surface is used to plan measurement points; for space curves, two left and right adjacent surfaces are used to plan measurement points. The present invention selects different methods for measuring point planning for different types of curves, which fully conforms to the geometric characteristics of different types of curves, avoids unnecessary complex measurement operations on plane curves, improves measurement efficiency, and ensures that sufficiently comprehensive and multi-angle measurement data can be obtained for complex geometric objects such as space curves, which helps to improve compensation accuracy and efficiency.

[0040] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0041] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0042] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0043] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0044] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A curve-conforming compensation processing method based on on-machine measurement, characterized in that: include: Model the workpiece to be processed, and obtain the curve to be compensated based on the model of the workpiece to be processed; Discretize the curve to be compensated, generate multiple original sampling points, and use them as theoretical measurement points of the adjacent surface of the curve to be compensated to form an on-machine measurement path; The measuring head is made to move along the on-machine measuring path to obtain the actual measuring point corresponding to each theoretical measuring point; Parameterize the curve to be compensated, and obtain the parameterized curve to be compensated; Project all theoretical measurement points onto the parameterized curve to be compensated to obtain the theoretical parameters corresponding to each theoretical measurement point; Calculate the difference vector between the coordinates of each theoretical measurement point and the coordinates of the corresponding actual measurement point, and use the projection distance of the difference vector in the theoretical normal direction as the error value between each theoretical measurement point and the corresponding actual measurement point; Acquire multiple tool position points on the machine measurement path, subtract the tool radius from the tool position point along the tool axis direction to obtain the corresponding theoretical tool center; project the multiple theoretical tool centers onto the parameterized curve to be compensated to obtain the cutting contact point corresponding to each tool position point; project each cutting contact point onto the parameterized curve to be compensated to obtain the cutting contact parameter corresponding to each cutting contact point; Based on the contact parameters of each contact point, as well as the theoretical parameters on the parameterized compensation curve and the corresponding error values, a contact error corresponding to each contact point is obtained by using a linear interpolation method; Based on the contact point normal and contact error of each contact point, an error vector corresponding to each contact point is obtained; After each cutting contact point is moved according to the error vector, the corresponding actual cutting contact point is obtained; Based on the actual cutting contact point and the tool radius, the actual tool tip point at each tool position point is obtained to form a compensation tool path for performing curve-conforming compensation on the to-be-compensated curve of the workpiece to be processed.

2. The curve-conforming compensation processing method based on on-machine measurement according to claim 1 is characterized in that: The discretization methods for the compensation curve include adaptive discretization and arc-length-chord-height mixed constraint discretization.

3. The curve-conforming compensation processing method based on on-machine measurement according to claim 1 is characterized in that: Parameterize the curve to be compensated and obtain the parameterized curve to be compensated, including: Based on the preset initial parameters and the length of each curve segment in the curve to be compensated, the first curve segment in the curve to be compensated is calculated. The starting point parameters corresponding to the curve segment , expressed as: , , Indicates the total number of curve segments in the curve to be compensated; The first Any point on the curve segment Parameters , expressed as: ; in, is the preset initial parameter, indicating the starting point parameter corresponding to the first curve segment in the curve to be compensated; Indicates The length of the curve segment; Indicates The starting point of the curve segment to The curve length at the point.

4. The curve-conforming compensation processing method based on on-machine measurement according to claim 1 is characterized in that: The curves to be compensated include plane curves and space curves; If the curve to be compensated is a plane curve, the original sampling points are arranged on a single adjacent surface as theoretical measured points, and the actual measured points are obtained by on-machine measurement; If the curve to be compensated is a space curve, theoretical measurement points are arranged on the left adjacent surface and the right adjacent surface of the space curve respectively, and the actual measurement points on the left and the right are obtained by on-machine measurement.

5. The curve-conforming compensation processing method based on on-machine measurement according to claim 4 is characterized in that: Based on the contact parameters of each contact point, as well as the theoretical parameters on the parameterized compensation curve and their corresponding error values, the contact error corresponding to each contact point is obtained using the linear interpolation method, which is expressed as: ； in, Indicates The contact error corresponding to each contact point is: and Respectively represent The theoretical measuring point adjacent to the left side of the contact point The theoretical measurement point adjacent to the right Theoretical parameters of Indicates The theoretical measuring point adjacent to the left side of the contact point The error value between the actual measurement point and its corresponding value is Indicates The theoretical measuring point adjacent to the right side of the contact point The error value between the actual measurement point and its corresponding value.

6. The curve-conforming compensation processing method based on on-machine measurement according to claim 5 is characterized in that: Based on the contact point normal and contact error of each contact point, the error vector corresponding to each contact point is obtained, including: When the curve to be compensated is a plane curve, the product of the contact point normal of each contact point and the contact error is taken as the error vector corresponding to each contact point; When the curve to be compensated is a spatial curve, on both the left adjacent surface and the right adjacent surface, the method includes: obtaining an isoparametric line on the adjacent surface based on the contact error and contact parameter of each contact point; offsetting the isoparametric line with the normal direction of the adjacent surface as the direction and the contact error as the length to obtain a corresponding offset line; Obtain the intersection point of the offset lines of the left adjacent face and the right adjacent face as the offset intersection point; A vector pointing from the cut contact point to the offset intersection point is obtained as the error vector corresponding to the cut contact point.

7. The curve-conforming compensation processing method based on on-machine measurement according to claim 6 is characterized in that: When the curve to be compensated is a plane curve, the product of the contact point normal of each contact point and the contact error is taken as the error vector corresponding to each contact point: ； in, Indicates The error vector of the contact point, Indicates The tangent contact normal of a tangent contact point, Indicates The contact error corresponding to each contact point.

8. The curve-conforming compensation processing method based on on-machine measurement according to claim 6 is characterized in that: Get the vector from the cut contact point to the offset intersection point as the error vector corresponding to the cut contact point, expressed as: ； in, Indicates The error vector of the contact point is Indicates A cutting contact point, Indicates the offset intersection point.

9. The curve-conforming compensation processing method based on on-machine measurement according to claim 1 is characterized in that: Based on the actual cutting contact point and tool radius, the actual tool tip point at each tool position point is obtained to form a compensation tool path for curve-conforming compensation of the to-be-compensated curve of the workpiece to be processed, including: The actual cutting contact point is offset along the normal direction of the cutting contact point by a distance of the tool radius to obtain the actual tool center; The actual tool center is offset in the opposite direction of the tool axis by a tool radius to obtain the actual tool position point; Based on the actual tool tip points corresponding to all tool position points, a compensation tool path is formed to perform curve-conforming compensation on the to-be-compensated curve of the workpiece to be processed.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the curve-conforming compensation processing method based on on-machine measurement as claimed in any one of claims 1 to 9 are implemented.

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