A multi-tool cooperative machining numerical control machine tool system based on dynamic error compensation

Abstract

The application relates to the technical field of numerical control machining, in particular to a multi-cutter cooperative machining numerical control machine tool system based on dynamic error compensation, which comprises the following units: a data acquisition unit for acquiring historical machining data; a path determination unit for determining a pre-machining path and an overlapping machining area of a blank; a machining execution unit for determining the cutting depth proportion of each cutter for executing single machining on the blank and executing machining; an image acquisition unit for acquiring surface images of the machining surface of the blank before and after machining in real time; a data analysis unit for determining a thermal diffusion area and a thermal deformation area of the machining surface of the blank and determining dynamic error compensation for the cutters according to the coverage of the thermal deformation area; a compensation regulation unit for determining the dynamic error compensation according to the coverage; and an optimization adjustment unit for optimizing the dynamic error compensation parameters based on the area proportion of the mutation points of the machining area. The application improves the machining precision of the multi-cutter cooperative machining numerical control lathe on workpieces.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of numerical control machining technology, and particularly relates to a multi-tool collaborative machining numerical control machine tool system based on dynamic error compensation. BACKGROUND

[0002] In the fields of aviation, aerospace and automobile manufacturing, the shape of workpieces is increasingly complex, and the precision requirement is continuously improved. Single tool cannot efficiently complete the machining task, and multi-tool collaborative machining becomes an inevitable choice. The geometric shapes and cutting performances of different tools are different, and errors are easily generated in collaborative machining due to tool interference and cutting force changes, affecting the machining precision and efficiency.

[0003] Chinese Patent Publication No. CN112517935A discloses a dynamic magnetic control spindle for regular polygon turning error compensation and a compensation method. The device includes a servo motor, a support frame, a power cutter, a micro cutter device, an end cover nut, and a magnetic control mechanism. After the power cutter and the workpiece spindle are positioned at the initial position, they rotate at a certain speed ratio for composite turning. The reset spring drives the tool holder to the starting position. The magnetic disc is installed with an electromagnet at the corresponding position of the micro cutter device in the radial direction of the power cutter. The power cutter, the magnetic disc, and the electromagnet rotate simultaneously, synchronously and in phase. The corresponding control current of each electromagnet is dynamically set according to the error compensation value to generate a corresponding magnetic force. The magnetic force generated by each electromagnet and the force generated by the corresponding reset spring jointly drive the tool holder to move a certain micro displacement in the radial direction of the cutter hole of the power cutter for turning compensation, ensuring that the machining of regular polygon workpieces can change the center distance from the tool head to the workpiece axis in real time to complete the turning error compensation.

[0004] Therefore, the dynamic magnetic control spindle for regular polygon turning error compensation and the compensation method have the following problems:

[0005] 1. In the cutting process, the error compensation of the tool is compensated by the magnetic force generated by the electromagnet. This compensation method is easily affected by the change of the current, leading to overcompensation or insufficient compensation of the error.

[0006] 2. In the actual cutting process, the temperature change of the workpiece surface and the shape change on the cutting path cannot be obtained in real time, leading to inaccurate tool compensation for the cutting process and reducing the cutting precision. SUMMARY

[0007] Therefore, the present application provides a multi-tool collaborative machining numerical control machine tool system based on dynamic error compensation, characterized by comprising,

[0008] a data acquisition unit configured to acquire historical machining data;

[0009] a path determining unit configured to determine a pre-machining path and an overlapping machining area of the blank according to a three-dimensional model of a target workpiece;

[0010] a machining executing unit configured to determine a cutting depth ratio of each tool of the numerical control machine to perform single machining on the blank based on the three-dimensional model, and execute machining;

[0011] an image acquiring unit configured to acquire surface images of a machining surface of the blank before machining and surface images of machining surfaces formed by the tools machining the blank in real time;

[0012] a data analyzing unit configured to analyze the surface images to determine a thermal diffusion area and a thermal deformation area of the machining surfaces formed by the tools machining the blank, and determine whether to perform dynamic error compensation on the tools according to a coverage rate of the thermal deformation area covering the overlapping machining area;

[0013] a compensation regulating unit configured to determine, according to the coverage rate, that the dynamic error compensation is an adjustment of machining coverage area so that the tools perform machining on a single machining path;

[0014] an optimization adjusting unit configured to determine, based on an area proportion of a mutation point of the machining area under the dynamic error compensation condition, to optimize a dynamic error compensation parameter of the tools.

[0015] Further, the machining executing unit determines the cutting depth ratio according to a comparison result of a thermal deformation rate and a preset thermal deformation rate in historical machining data of the numerical control machine for the blanks.

[0016] The cutting depth ratio is determined based on a comparison result of a thermal deformation rate and a preset thermal deformation rate in historical machining data of the numerical control machine for the blanks.

[0017] Further, the data analyzing unit determines whether to perform dynamic error compensation on the tools based on a comparison result of a coverage rate of the thermal deformation area covering the overlapping machining area and a preset coverage rate.

[0018] Further, the compensation regulating unit, under the condition of determining to perform dynamic error compensation, determines, based on a difference value of the coverage rate and a preset difference value, to adjust a machining coverage area of a single machining path of the tools in the pre-machining path;

[0019] wherein the first adjustment strategy is to reduce, under the condition of the machining coverage area of the single machining path of the first tool in the pre-machining path of the first tool performing machining, the machining coverage area of the single machining path of the second tool after the first tool performing machining.

[0020] Further, the plurality of tools includes a first tool disposed on the first spindle and a second tool disposed on the second spindle.

[0021] Further, the second adjustment strategy is to increase the machining coverage area of the second tool on the single machining path after the first tool performs machining on the single machining path in the pre-machining path of the first tool to offset the machining error of the first tool.

[0022] Further, the optimization adjustment unit determines to optimize the dynamic error compensation parameter of the first tool based on the comparison result of the first area ratio of the abrupt change point on the single machining path in the pre-machining path of the first tool performing machining and the preset first area ratio.

[0023] Further, the optimization adjustment unit determines to optimize the dynamic error compensation parameter of the second tool according to the comparison result of the second area ratio of the abrupt change point on the single machining path after the first tool performs optimization machining and the preset second area ratio.

[0024] Further, the optimization of the dynamic error compensation parameter of the first tool is to reduce the cutting speed of the first tool and increase the cutting depth of the first tool.

[0025] Further, the optimization of the dynamic error compensation parameter of the second tool is to reduce the cutting speed of the second tool and increase the cutting depth of the second tool.

[0026] Compared with the prior art, the beneficial effects of the present application are that the present application constructs a three-dimensional model of the target machining workpiece, and further constructs a pre-machining path of the target machining workpiece according to the model. The three-dimensional model provides an accurate geometric shape of the target machining workpiece for machining, and the pre-machining path can be accurately planned according to the details of the model to ensure that the cutting path of each tool is highly matched with the actual shape of the workpiece, avoiding collision or interference between the tool and the workpiece, and improving machining precision.

[0027] Further, by acquiring the thermal diffusion area and the corresponding thermal deformation area in the thermal diffusion area on the surface of the machining workpiece in real time during the machining process, the surface changes of the workpiece caused by temperature changes during the machining process can be understood in real time, and the size and shape deviations caused by thermal deformation can be found in time to provide accurate error information for subsequent machining, effectively reducing the influence of thermal deformation on machining precision, and improving the size precision and shape precision of the machining workpiece.

[0028] Further, the data analysis unit determines whether to perform dynamic error compensation on the plurality of tools based on a comparison result of the coverage rate of the thermal deformation area in the overlap machining area and a preset coverage rate. When the coverage rate is too small, no dynamic error compensation is performed on the plurality of tools. When the coverage rate is too large, dynamic error compensation is performed on the plurality of tools. In this way, the size and shape deviations caused by thermal deformation can be effectively corrected, the machining precision is significantly improved, the machined workpiece is closer to the design requirements, unnecessary compensation operations that may introduce new errors are avoided, and the stability and machining precision of the machining process are ensured.

[0029] Further, the first area ratio of the mutation points on the single machining path in the pre-machining path of the first tool is compared with the preset first area ratio to determine whether to optimize the dynamic error compensation parameters of the first tool. The area ratio of the mutation points on the single machining path of the workpiece can be monitored in real time, the machining parameters of the first tool can be adjusted in time, the problem of excessive error caused by the second tool when machining due to error accumulation in the overlap machining area can be avoided, and the machining precision is improved.

[0030] Further, the second area ratio of the mutation points on the single machining path after the first tool performs optimized machining is compared with the preset second area ratio to determine whether to optimize the dynamic error compensation parameters of the second tool. The area of the mutation points on the single machining path after the first tool performs optimized machining on the workpiece can be further monitored, the machining parameters of the second tool can be further adjusted, the error of the first tool can be compensated, the machining precision is improved, and the machining precision of the machined workpiece is ensured to be qualified. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The unit connection block diagram of the multi-tool cooperative machining numerical control machine tool system based on dynamic error compensation according to the embodiment of the application;

[0032] Figure 2 The multi-tool cooperative machining numerical control machine tool structure diagram of the multi-tool cooperative machining numerical control machine tool system based on dynamic error compensation according to the embodiment of the application;

[0033] Figure 3 The judgment diagram for determining whether to perform dynamic error compensation on the plurality of tools according to the coverage rate of the overlap machining area according to the embodiment of the application;

[0034] Figure 4 The judgment diagram for determining the corresponding adjustment strategy according to the difference of the coverage rate according to the embodiment of the application;

[0035] Figure 5The first area ratio of the mutation point is used to determine the dynamic error compensation parameter of the first tool for optimization in the embodiment of the application.

[0036] Figure 6 The second area ratio of the mutation point is used to determine the dynamic error compensation parameter of the second tool for optimization in the embodiment of the application.

[0037] In the figure, 1 is a first main shaft, 2 is a second main shaft, 3 is a first tool, 4 is a second tool, and 5 is a blank. DETAILED DESCRIPTION

[0038] In order to make the objects and advantages of the present application clearer, the present application will be further described in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0039] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not used to limit the protection scope of the present application.

[0040] It should be noted that, in the description of the present application, unless explicitly defined and limited, the terms "mounting", "connection" and "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium, or internal communication of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0041] Please refer to Figures 1 to 2 as shown, Figure 1 The unit connection block diagram of the multi-tool cooperative machining numerical control machine tool system based on dynamic error compensation in the embodiment of the application is shown in the figure. Figure 2 The multi-tool cooperative machining numerical control machine tool structure schematic diagram of the multi-tool cooperative machining numerical control machine tool system based on dynamic error compensation in the embodiment of the application is shown in the figure.

[0042] The multi-tool cooperative machining numerical control machine tool system based on dynamic error compensation in the embodiment of the application comprises:

[0043] The data acquisition unit is used to acquire the historical machining data of the numerical control machine tool.

[0044] The path determination unit is used to determine the pre-machining path and the overlapping machining area of the blank 5 according to the three-dimensional model of the target workpiece.

[0045] a processing execution unit connected with the path determination unit, configured to determine a cutting depth ratio of a single tool of the plurality of tools to the workpiece 5 based on the three-dimensional model to perform processing;

[0046] an image acquisition unit connected with the processing execution unit, configured to acquire a surface image of a processing surface formed by the single tool in real time;

[0047] a data analysis unit connected with the data acquisition unit, configured to analyze the surface image to determine a thermal diffusion area and a thermal deformation area of the processing surface of the workpiece 5, and determine whether to perform dynamic error compensation for the plurality of tools according to a coverage rate of the thermal deformation area covering the overlap processing area;

[0048] a compensation regulation unit connected with the data analysis unit and the processing execution unit respectively, configured to determine a dynamic error compensation parameter of the plurality of tools;

[0049] an optimization adjustment unit connected with the compensation regulation unit and the processing execution unit respectively, configured to determine to optimize the dynamic error compensation parameter of the plurality of tools based on an area proportion of a mutation point of the processing area under the dynamic error compensation condition.

[0050] Specifically, the processing execution unit is connected with the data acquisition unit, and the cutting depth ratio is determined according to a comparison result of a thermal deformation rate and a preset thermal deformation rate in historical processing data of the plurality of workpieces 5 of the numerical control machine tool, wherein,

[0051] if the thermal deformation rate is less than or equal to the preset thermal deformation rate, the cutting depth ratio is determined as a first cutting depth ratio;

[0052] if the thermal deformation rate is greater than the preset thermal deformation rate, the cutting depth ratio is determined as a second cutting depth ratio.

[0053] Preferably, the preset thermal deformation rate is 0.6, and the value range and the preferred value range of the preset thermal deformation rate can be determined according to actual conditions, which are not limited here.

[0054] Preferably, the thermal deformation rate is first obtained according to a difference between a temperature after processing and a processing environment temperature and a difference between a size after processing and a design size in the historical processing data, and then the thermal deformation rate is obtained by using the ratio of the difference between the size after processing and the design size and the difference between the temperature after processing and the processing environment temperature.

[0055] In the embodiment of the present application, the preset thermal deformation rate is 0.6, and in the implementation, the cutting depth ratio is determined according to the comparison result of the thermal deformation rate and the preset thermal deformation rate in the historical machining data of the plurality of blanks 5 of the numerical control machine tool, for example, when the thermal deformation rate is 0.5, which meets the condition that the thermal deformation rate is less than the preset thermal deformation rate, the cutting depth ratio is determined as the first cutting depth ratio, for example, when the thermal deformation rate is 0.7, which meets the condition that the thermal deformation rate is greater than the preset thermal deformation rate, the cutting depth ratio is determined as the second cutting depth ratio.

[0056] The first cutting depth ratio is the ratio of the first tool cutting depth to the second tool 4 cutting depth, that is, 3:5, and the second cutting depth ratio is the ratio of the first tool cutting depth to the second tool 4 cutting depth, that is, 5:2.

[0057] In the embodiment of the present application, the surface image is the image of the thermal diffusion area of the machined surface of the blank 5 formed by the plurality of tools, the infrared thermal imaging is an infrared thermal imager arranged near the machining area, the infrared radiation energy emitted by the surface of the blank 5 is detected, converted into a temperature value, and a temperature field thermal image is generated, the surface temperature distribution of the blank 5 is mapped by pseudo-color, and the temperature distribution and thermal diffusion area of the machining area are obtained.

[0058] In the embodiment of the present application, the plurality of tools are the first tool 3 arranged on the first spindle 1 and the second tool 4 arranged on the second spindle 2.

[0059] Specifically, the image of the thermal diffusion area of the surface of the blank 5 can realize thermal deformation compensation in the machining process, optimize the cutting parameters of the plurality of tools, reduce the precision error caused by uneven heat dispersion, improve the machining efficiency, realize rapid adjustment of the cutting parameters of the plurality of tools, and ensure the stability and reliability of the machining quality.

[0060] Specifically, the data analysis unit determines the thermal deformation area based on the surface image of the machined surface of the blank 5 before machining and the surface image of the machined surface of the blank 5 formed by the single tool.

[0061] In the embodiment of the present application, the hot deformation area is determined based on the surface image of the machining surface of the blank 5 before machining acquired by the image acquisition unit in real time and the surface image of the machining surface formed by machining the blank 5 by a single tool. In actual application, the surface images of the machining surface before and after machining of the blank 5 are respectively acquired by using a thermal imager, and image processing tools such as OpenCV are used to perform geometric correction and registration on the images before and after machining to eliminate errors caused by camera displacement or angle change. The surface image of the machining surface of the blank 5 before machining is taken as a reference image, and the surface image of the machining surface of the blank 5 after machining is taken as a target image. A virtual grid is divided on the image by using a DIC algorithm, a displacement vector of each pixel point is calculated by using ZNSSD, and a displacement field is extracted to identify a displacement significant area. A corresponding displacement threshold value is set according to the machining precision of the blank 5, the displacement threshold value is in a range of 3-8 μm, and the present application preferably takes 5 μm as the value. The area where the displacement exceeds the displacement threshold value is marked as a hot deformation area.

[0062] Please continue to refer to Figures 3 to 6 as shown, Figure 3 The judgment chart for determining whether to perform dynamic error compensation on the plurality of tools according to the coverage rate of the overlapping machining area is provided for the embodiment of the present application; Figure 4 The judgment chart for determining the corresponding adjustment strategy according to the difference of the coverage rates is provided for the embodiment of the present application; Figure 5 The dynamic error compensation parameter of the first tool is optimized according to the first area ratio of the mutation point for the embodiment of the present application; Figure 6 The dynamic error compensation parameter of the second tool is optimized according to the second area ratio of the mutation point for the embodiment of the present application.

[0063] Specifically, the data analysis unit determines whether to perform dynamic error compensation on the plurality of tools based on the comparison result of the coverage rate of the hot deformation area in the overlapping machining area with the preset coverage rate;

[0064] If the coverage rate is less than or equal to the preset coverage rate, it is determined that dynamic error compensation is not performed on the plurality of tools;

[0065] If the coverage rate is greater than the preset coverage rate, it is determined that dynamic error compensation is performed on the plurality of tools;

[0066] The value range of the preset coverage rate is 20%-40%, and the present application preferably takes 30% as the value. The value range and the preferred value range of the preset coverage rate can be determined according to actual conditions, which are not limited here.

[0067] The coverage rate is obtained by collecting the thermal image of the surface of the workpiece 5 in real time by using an infrared thermal imager, collecting the deformation image of the surface of the workpiece by using a DIC system, ensuring that the data collection of the two is carried out at the same time, processing the collected thermal image, extracting the thermal deformation area, using the DIC software to analyze the change of the speckle pattern, calculating the displacement field and the strain field of the surface of the workpiece, thereby determining the thermal deformation area, matching the thermal deformation area image and the deformation field image in space and aligning the coordinate systems, ensuring that the two are consistent in space, and using the area analysis tool in the image processing software to count the ratio of the pixel number of the thermal deformation area to the total pixel number of the overlapping machining area, thereby obtaining the coverage rate.

[0068] In the embodiment of the present application, the preset coverage rate is 30%, and in the implementation, whether to perform dynamic error compensation on the plurality of cutters is determined based on the comparison result of the coverage rate of the thermal deformation area in the overlapping machining area and the preset coverage rate, for example, in the case that the coverage rate is 25%, the coverage rate is less than the preset coverage rate, at this time, the influence of the thermal deformation area on the overlapping machining area is small, and the influence on the machining precision is small, and it is determined that the dynamic error compensation is not performed on the plurality of cutters, for example, in the case that the coverage rate is 35%, the coverage rate is greater than the preset coverage rate, at this time, the influence of the thermal deformation area on the overlapping machining area is large, and the influence on the machining precision is large, and it is determined that the dynamic error compensation is performed on the plurality of cutters.

[0069] Specifically, the compensation control unit determines to adjust the machining coverage area of a single machining path in the pre-machining path for machining of the plurality of cutters based on the difference value of the coverage rate and the preset difference value under the condition of determining to perform dynamic error compensation.

[0070] If the difference value is less than or equal to the preset difference value, a first adjustment strategy of adjusting the machining coverage area of a single machining path in the pre-machining path for machining of the plurality of cutters is determined.

[0071] If the difference value is greater than the preset difference value, a second adjustment strategy of adjusting the machining coverage area of a single machining path in the pre-machining path for machining of the plurality of cutters is determined.

[0072] The preset difference value is preferably 2% and has a value range of 1%-4%, which can be determined according to actual conditions and is not limited here.

[0073] The difference value of the coverage rate is the difference value of the coverage rate of the thermal deformation area in the overlapping machining area and the preset coverage rate.

[0074] In the embodiment of the present application, the preset difference value is 2%, and in the implementation, the machining coverage area of a single machining path in the pre-machining path for performing machining on the plurality of cutters is adjusted based on the difference value of the coverage rate and the preset difference value. For example, when the difference value is 1%, the difference value is less than the preset difference value, which indicates that the coverage rate of the thermal deformation region in the overlapping machining region is close to the preset coverage rate, and a first adjustment strategy for adjusting the machining coverage area of a single machining path in the pre-machining path for performing machining on the plurality of cutters is determined. For example, when the difference value is 3%, the difference value is greater than the preset difference value, which indicates that the coverage rate of the thermal deformation region in the overlapping machining region is greater than the preset coverage rate, and a second adjustment strategy for adjusting the machining coverage area of a single machining path in the pre-machining path for performing machining on the plurality of cutters is determined.

[0075] Specifically, the first adjustment strategy is to reduce the machining coverage area of a single machining path of the second cutter 4 after the first cutter 3 performs machining on the single machining path under the condition of the machining coverage area of a single machining path in the pre-machining path for performing machining on the first cutter 3;

[0076] The second adjustment strategy is to increase the machining coverage area of a single machining path of the second cutter 4 after the first cutter 3 performs machining on the single machining path under the condition of the machining coverage area of a single machining path in the pre-machining path for performing machining on the first cutter 3, so as to offset the machining error of the first cutter 3.

[0077] Specifically, the optimization adjustment unit determines to optimize the dynamic error compensation parameters of the plurality of cutters based on the area proportion of the abrupt change point of the machining region under the condition of dynamic error compensation, and determines to optimize the dynamic error compensation parameters of the first cutter 3 based on the comparison result of the first area proportion of the abrupt change point on a single machining path in the pre-machining path for performing machining on the first cutter 3 and a preset first area proportion, wherein

[0078] If the first area proportion is less than or equal to the preset first area proportion, it is determined that the dynamic error compensation parameters of the first cutter 3 are not optimized;

[0079] If the first area proportion is greater than the preset first area proportion, it is determined that the dynamic error compensation parameters of the first cutter 3 are optimized;

[0080] The preset first area proportion has a value range of 15% to 35%, and the present application preferably has a value of 20%. The value range and the preferred value range of the preset first area proportion can be determined according to actual conditions, which are not limited here.

[0081] In the embodiment of the present application, the first area ratio is obtained by scanning a single machining path in the pre-machining path of the first tool 3 by a three-dimensional scanner, acquiring point cloud data of the single machining path, preprocessing the collected point cloud data by point cloud processing software, such as CloudCompare, segmenting the preprocessed point cloud data to divide the single machining path area, calculating the normal vector of each point of the segmented single machining path area point cloud, calculating the curvature of the point cloud based on the normal vector, identifying the mutation point according to the curvature threshold, extracting the identified mutation point and its neighborhood point to form a triangular net of the mutation point area, calculating the area of the mutation point area and the total area of the single machining path area respectively, and finally obtaining the first area ratio by the ratio of the total area of the mutation point area to the total area of the single machining path area.

[0082] The curvature threshold has a value range of 0.001-0.01, and the preferred value of the present application is 0.008.

[0083] In the embodiment of the present application, the preset first area ratio has a value of 20%, and the first area ratio of the mutation point on the single machining path in the pre-machining path of the first tool 3 is compared with the preset first area ratio to determine whether to optimize the dynamic error compensation parameter of the first tool 3, for example, when the first area ratio has a value of 15%, which is less than the preset first area ratio, the machining precision of the single machining path in the pre-machining path of the first tool 3 is qualified, and it is determined that the dynamic error compensation parameter of the first tool 3 is not optimized, for example, when the first area ratio has a value of 25%, which is greater than the preset first area ratio, the machining precision of the single machining path in the pre-machining path of the first tool 3 is unqualified, and it is determined that the dynamic error compensation parameter of the first tool 3 is optimized.

[0084] In the embodiment of the present application, the optimization of the dynamic error compensation parameter of the first tool 3 is to reduce the cutting speed of the first tool 3 and increase the cutting depth of the first tool 3, the reduction range of the cutting speed is 0.6-0.9 times of the original cutting speed, and the preferred reduction value of the present application is 0.8 times, the increase range of the cutting depth is 1.4-1.8 times of the original cutting depth, and the preferred increase value of the present application is 1.6 times, at this time, the first machining tool uses the optimized machining parameter to machine the single machining path, and at the same time, the point cloud data is used to obtain the area ratio of the mutation point on the single machining path area, and the machining parameter of the second tool 4 is dynamically optimized.

[0085] Specifically, the optimization adjustment unit determines to optimize the dynamic error compensation parameters of the second tool 4 according to a comparison result of a second area ratio of the mutation points on the single machining path of the first tool 3 after the optimization machining by the second tool 4 and a preset second area ratio after optimizing the dynamic error compensation parameters of the first tool 3, wherein,

[0086] If the second area ratio is less than or equal to the preset second area ratio, it is determined that the dynamic error compensation parameters of the second tool 4 are not optimized.

[0087] If the second area ratio is greater than the preset second area ratio, it is determined that the dynamic error compensation parameters of the second tool 4 are optimized.

[0088] The preset second area ratio has a value range of 8% to 15%, and the application preferably has a value of 12%. The value range and the preferred value range of the preset second area ratio can be determined according to the actual situation, which is not limited here.

[0089] The second area ratio is obtained by scanning the single machining path area of the first tool 3 after the optimization machining by the three-dimensional scanner, obtaining the point cloud data of the single machining path area, preprocessing the collected point cloud data by using the point cloud processing software, segmenting the preprocessed point cloud data to divide the single machining path area, calculating the normal vector of each point of the segmented single machining path area point cloud, calculating the curvature of the point cloud based on the normal vector, identifying the mutation points according to the curvature threshold, extracting the identified mutation points and their neighborhood points to form a triangular mesh of the mutation point area, calculating the area of the mutation point area and the total area of the single machining path area respectively, and finally obtaining the second area ratio through the ratio of the total area of the mutation point area to the total area of the single machining path area.

[0090] In the embodiment of the present application, the preset second area ratio value is 12%, and the second area ratio of the mutation point on the single machining path after the first tool 3 performs the optimized machining on the second tool 4 is compared with the preset second area ratio to determine whether to optimize the dynamic error compensation parameter of the second tool 4. For example, when the second area ratio is 10%, the second area ratio is less than the preset second area ratio, and the machining precision of the single machining path in the pre-machining path of the first tool 3 performing the optimized machining is qualified, it is determined that the dynamic error compensation parameter of the second tool 4 is not optimized. For example, when the second area ratio is 15%, the second area ratio is greater than the preset second area ratio, and the machining precision of the single machining path in the pre-machining path of the first tool 3 performing the optimized machining is unqualified, it is determined that the dynamic error compensation parameter of the second tool 4 is optimized.

[0091] In the embodiment of the present application, the optimization of the dynamic error compensation parameter of the second tool 4 is to reduce the cutting speed of the second tool 4 and increase the cutting depth of the second tool 4. The reduction range of the cutting speed is 0.85-0.95 times of the original cutting speed, and the present application preferably reduces the value to 0.90 times. The increase range of the cutting depth is 1.0-1.3 times of the original cutting depth, and the present application preferably increases the value to 1.1 times. At this time, the second tool 4 uses the optimized machining parameter to machine the single machining path after the first tool 3 performs the optimized machining, to complete the machining.

[0092] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will fall within the protection scope of the present application.

Claims

1. A multi-tool coordinated machining numerical control machine tool system based on dynamic error compensation, characterized by, Comprising, a data acquisition unit configured to acquire historical machining data of a numerical control machine tool; a path determination unit configured to determine a pre-machining path and an overlapping machining area of a workpiece based on a three-dimensional model of a target workpiece; a machining execution unit configured to determine a cutting depth ratio of a plurality of tools of the numerical control machine tool for performing single machining on the workpiece based on the three-dimensional model, and perform machining; an image acquisition unit configured to acquire surface images of a machining surface of the workpiece before machining and surface images of machining surfaces formed by the plurality of tools machining the workpiece in real time; a data analysis unit configured to analyze the surface images to determine a thermal diffusion area and a thermal deformation area of the machining surfaces formed by the plurality of tools machining the workpiece, and determine dynamic error compensation for the plurality of tools based on a coverage rate of the thermal deformation area covering the overlapping machining area; wherein the machining coverage area of a single machining path in the pre-machining path for performing machining by the plurality of tools is adjusted based on a difference between the coverage rate and a preset coverage rate; wherein a first adjustment strategy is to reduce the machining coverage area of a single machining path of the second tool on a single machining path after machining by the first tool under the condition that the machining coverage area of a single machining path in the pre-machining path for machining by the first tool; a second adjustment strategy is to increase the machining coverage area of the single machining path of the second tool on the single machining path after machining by the first tool under the condition that the machining coverage area of a single machining path in the pre-machining path for machining by the first tool, so as to offset the machining error of the first tool; a compensation regulation unit configured to determine that the dynamic error compensation is an adjustment of the machining coverage area for the plurality of tools to perform machining on a single machining path based on the coverage rate; an optimization adjustment unit configured to optimize dynamic error compensation parameters of the plurality of tools based on an area ratio of a mutation point of a machining area under the condition of dynamic error compensation.

2. The dynamic error compensation based multi-tool coordinated machining CNC machine tool system according to claim 1, wherein, The cutting depth ratio is determined based on a comparison result of a thermal deformation rate of the plurality of workpieces in the historical machining data of the numerical control machine tool and a preset thermal deformation rate.

3. The dynamic error compensation based multi-tool coordinated machining CNC machine tool system according to claim 2, wherein, The data analysis unit determines dynamic error compensation for the plurality of tools based on a comparison result that the coverage rate of the thermal deformation area in the overlapping machining area is greater than a preset coverage rate.

4. The dynamic error compensation based multi-tool coordinated machining CNC machine tool system according to claim 1, wherein, The plurality of tools includes a first tool arranged on a first spindle and a second tool arranged on a second spindle.

5. The dynamic error compensation based multi-tool coordinated machining CNC machine tool system according to claim 1, wherein, The optimization adjustment unit optimizes the dynamic error compensation parameters of the first tool based on a comparison result of a first area ratio of a mutation point on a single machining path in the pre-machining path for machining by the first tool and a preset first area ratio.

6. The dynamic error compensation based multi-tool coordinated machining CNC machine tool system according to claim 5, wherein, The optimization adjustment unit optimizes the dynamic error compensation parameters of the second tool based on a comparison result of a second area ratio of a mutation point on a single machining path after the first tool performs optimized machining and a preset second area ratio.

7. The dynamic error compensation based multi-tool coordinated machining CNC machine tool system according to claim 6, wherein, The optimization of the dynamic error compensation parameters of the first tool is to reduce the cutting speed of the first tool and increase the cutting depth of the first tool.

8. The dynamic error compensation based multi-tool coordinated machining CNC machine tool system according to claim 7, wherein, The dynamic error compensation parameters of the second tool are optimized to reduce a cutting speed of the second tool and to increase a cutting depth of the second tool.

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