On-machine calibration method, device and equipment for flat-bottom cylindrical probe

Abstract

The invention relates to the technical field of probe calibration, and discloses a flat-bottom cylindrical probe on-machine calibration method, device and equipment, and the method comprises the steps: carrying out the modeling of a to-be-calibrated flat-bottom cylindrical probe and a ring gauge, obtaining a to-be-calibrated flat-bottom cylindrical probe model and a ring gauge model, and generating a radius calibration measurement path and a length calibration measurement path; the ring gauge is arranged on the table top of a machine table, the reference cutter is used for obtaining a measurement original point, the flat-bottom cylindrical probe to be calibrated is made to run along the calibration measurement path, and a corresponding actual measurement point set is obtained; fitting all the actual measurement points in the radius actual measurement point set into a circle by using a least square method circle fitting principle, and obtaining the equivalent diameter of the calibration flat-bottom cylindrical probe based on the fitting circle center and the fitting radius; the average value of the Z-axis coordinates of all the actual measurement points in the length actual measurement point set serves as length deviation, the actual length of the flat-bottom cylindrical probe to be calibrated is compensated, and the calibrated length is obtained; and based on the equivalent diameter and the calibration length, completing calibration of the flat-bottom cylindrical probe to be calibrated.

Description

Technical Field

[0001] The present invention relates to the technical field of probe calibration, and in particular to a method, device and equipment for calibrating a flat-bottom cylindrical probe on a machine tool. Background Art

[0002] As is well known, a probe is an important part of a measurement system. Its working principle is that when measuring a part, the probe contacts the workpiece to be measured, causing displacement in the internal structure of the probe head, thereby generating relevant signals in the internal sensor; after the numerical control machine tool receives the relevant signals, the motion controller sends the current coordinates to the measurement software; the software then obtains accurate coordinate values based on these coordinate data, combined with the probe radius and the normal direction of the contact point.

[0003] However, due to some errors in the actual production and assembly processes of the probe, these errors will cause deviations in the length and diameter of the probe; when the probe is installed on the probe head, there will be deviations between the actual position and shape and the probe head model; the diameter of the probe will be inaccurate due to wear during use; in actual measurement work, it may be necessary to select probes with different lengths, shapes and diameters according to the shape and size of the workpiece to be measured. Therefore, based on the displacement at the time of triggering, the actual radius of the probe, and the installation errors, etc., it is necessary to calibrate the actual radius value of the probe to ensure that these probes with different configurations can accurately measure. Moreover, due to the reason of spindle thermal elongation, the length of the probe is actually unstable and constantly changing, which requires compensating the tool length of the probe before measurement.

[0004] There are mainly two ways to calibrate the flat-bottom cylindrical probe at the numerical control machine tool end: the calibration macro program built into the numerical control system and the calibration macro program of Renishaw probe head. The calibration macro program built into the numerical control system is usually written for specific machine tool models and configurations, and its parameter settings are relatively fixed, making it difficult to flexibly adjust according to different measurement tasks and workpiece requirements. Although the calibration macro program of Renishaw probe head provides relatively rich measurement functions to a certain extent, for some complex measurement tasks, such as surface measurement, measurement of non-standard shaped workpieces, etc., its functions still have limitations. Moreover, different versions of the numerical control system may have differences in supporting the macro program, and some new functions and instructions may not be available in the old version of the system, while the in-machine measurement software usually needs to be compatible with different versions of the numerical control system, which leads to the calibration macro program built into the numerical control system being unable to run properly or having inaccurate running results on some numerical control systems. There are also compatibility problems among various models and different software versions of Renishaw probe heads; if the probe head model used does not match the calibration macro program or the software versions are inconsistent, calibration failure or inaccurate measurement results may occur.

[0005] In summary, the compensation methods, variables used, etc. of the above two calibration methods each have their own scope of application and usage methods: the built-in macro program of the numerical control system is applicable to the measurement methods provided by the machine tool itself, and the Renishaw probe calibration program is applicable to Renishaw macro program programming; while the in-machine measurement software has its own compensation method. If the calibration results of the above two methods are directly used, the measurement results may be inaccurate due to incompatibility. Moreover, for different numerical control systems, their built-in calibration methods and compensation methods are different, and the versatility is poor; if the macro program calibration and compensation methods provided by the numerical control system are adopted, the in-machine measurement software will become relatively complex and difficult to use, and it is difficult to promote. It cannot be applied to different machine tools, and the operation is complex, resulting in easy errors in the calibration results. Therefore, the above two methods are okay for simple origin centering and finding, but for the in-machine measurement software, they are not flexible enough, the calibration results are inconsistent, and the versatility is poor. Summary of the Invention

[0006] For this reason, the technical problem to be solved by the present invention is to overcome the problems in the prior art that the calibration method of the flat-bottom cylindrical probe is not applicable to the in-machine measurement software, is not flexible to use, has low accuracy, and has poor versatility.

[0007] To solve the above technical problem, the present invention provides a method for in-machine calibration of a flat-bottom cylindrical probe, including: Model the flat-bottom cylindrical probe to be calibrated and the ring gauge to obtain the model of the flat-bottom cylindrical probe to be calibrated and the model of the ring gauge; Based on the model of the flat-bottom cylindrical probe to be calibrated and the model of the ring gauge, obtain the inner circular surface group measurement path of the ring gauge as the radius calibration measurement path, and obtain the upper end surface group measurement path of the ring gauge as the length calibration measurement path; Place the ring gauge on the machine table surface and use the reference tool to obtain the measurement origin; Starting from the measurement origin, let the flat-bottom cylindrical probe to be calibrated run along the radius calibration measurement path, obtain the relative coordinate values each time the flat-bottom cylindrical probe to be calibrated is triggered during the running process, and construct a set of radius measured points; Using the least squares circle fitting principle, fit all the measured points in the set of radius measured points into a circle, and obtain the fitting center and fitting radius of the fitted circle; Based on the diameter of the ring gauge and the fitting radius, obtain the equivalent diameter of the flat-bottom cylindrical probe to be calibrated; Starting from the measurement origin, let the flat-bottom cylindrical probe to be calibrated run along the length calibration measurement path, obtain the relative coordinate values each time the flat-bottom cylindrical probe to be calibrated is triggered during the running process, and construct a set of length measured points; Taking the average value of the Z-axis coordinates of all the measured points in the set of length measured points as the length deviation of the flat-bottom cylindrical probe to be calibrated, compensate the actual length of the flat-bottom cylindrical probe to be calibrated, and obtain the calibrated length; Calibration of the cylindrical probe with a flat bottom to be calibrated is completed based on its equivalent diameter and calibration length.

[0008] Preferably, use 3D CAM to model the cylindrical probe with a flat bottom to be calibrated and the ring gauge, obtain the model of the cylindrical probe with a flat bottom to be calibrated and the model of the ring gauge, and generate the measurement paths for the inner circular surface group and the upper end surface group of the ring gauge.

[0009] Preferably, place the ring gauge on the machine tabletop and use the reference tool to obtain the measurement origin, including: Make the reference tool vertically contact the top of the ring gauge to obtain the current position height of the reference tool, which is the Z-axis coordinate of the measurement origin; Use the reference tool to obtain the center point of the ring gauge, and use the horizontal and vertical coordinates of the center point of the ring gauge as the X-axis coordinate and Y-axis coordinate of the measurement origin.

[0010] Preferably, use the principle of least squares circle fitting to fit all the measured points in the set of measured points of the radius into a circle, including: Define the parametric equation of the fitting circle as: ; Based on the measured points in the set of measured points of the radius, construct an error function, expressed as: ; Use the gradient descent method to obtain the parameters , and when the error function converges, and substitute them into the parametric equation of the fitting circle to obtain the target fitting circle expression, which is ; Among them, , and respectively represent the X-axis coordinate and Y-axis coordinate of the th measured point in the set of measured points of the radius, , represents the total number of measured points in the set of measured points of the radius.

[0011] Preferably, obtain the fitting center and fitting radius of the fitting circle, including: Obtain the fitting center of the fitting circle, and its value is: ; Obtain the fitting radius of the fitting circle, expressed as: .

[0012] Preferably, based on the diameter of the ring gauge and the fitting radius, obtain the equivalent diameter of the cylindrical probe with a flat bottom to be calibrated, expressed as: ; Among them, represents the equivalent diameter of the cylindrical stylus with a flat tip to be calibrated, represents the diameter of the ring gauge, represents the fitted radius.

[0013] Preferably, the average value of the Z-axis coordinates of all measured points in the set of length measured points is used as the length deviation of the cylindrical stylus with a flat tip to be calibrated, denoted as: ; wherein, represents the length deviation of the cylindrical stylus with a flat tip to be calibrated, represents the Z-axis coordinate of the th measured point in the set of length measured points, , represents the total number of measured points in the set of length measured points.

[0014] Preferably, the actual length of the cylindrical stylus with a flat tip to be calibrated is added to the length deviation to obtain the calibrated length of the cylindrical stylus with a flat tip to be calibrated, denoted as: ; wherein, represents the calibrated length of the cylindrical stylus with a flat tip to be calibrated, represents the actual length of the cylindrical stylus with a flat tip to be calibrated.

[0015] This embodiment also provides a calibration device based on the in-machine calibration method of the cylindrical stylus with a flat tip as described above, including: A model construction module for modeling the cylindrical stylus with a flat tip to be calibrated and the ring gauge to obtain a model of the cylindrical stylus with a flat tip to be calibrated and a model of the ring gauge; A path generation module for obtaining the inner circular surface group measurement path of the ring gauge as the radius calibration measurement path and the upper end surface group measurement path of the ring gauge as the length calibration measurement path based on the model of the cylindrical stylus with a flat tip to be calibrated and the model of the ring gauge; An origin acquisition module for placing the ring gauge on the machine table surface and using a reference tool to obtain a measurement origin; An equivalent diameter calculation module for starting from the measurement origin, making the cylindrical stylus with a flat tip to be calibrated run along the radius calibration measurement path, obtaining the relative coordinate values when the cylindrical stylus with a flat tip to be calibrated is triggered each time during the running process, and constructing a set of radius measured points; using the least squares circle fitting principle to fit all the measured points in the set of radius measured points into a circle, and obtaining the fitted center and the fitted radius of the fitted circle; obtaining the equivalent diameter of the cylindrical stylus with a flat tip to be calibrated based on the diameter of the ring gauge and the fitted radius; The calibration length calculation module is used to start from the measurement origin, make the cylindrical flat probe to be calibrated run along the length calibration measurement path, obtain the relative coordinate values each time the cylindrical flat probe to be calibrated is triggered during the running process, and construct a set of actual length measurement points; use the average value of the Z-axis coordinates of all the actual measurement points in the set of actual length measurement points as the length deviation of the cylindrical flat probe to be calibrated, compensate the actual length of the cylindrical flat probe to be calibrated, and obtain the calibration length. The calibration module is used to complete the calibration of the cylindrical flat probe to be calibrated based on the equivalent diameter and calibration length of the cylindrical flat probe to be calibrated.

[0016] This embodiment also provides a on-machine calibration device for a cylindrical flat probe, including: A machine tool; The cylindrical flat probe to be calibrated, installed on the preset probe head of the machine tool; A ring gauge, placed on the tabletop of the machine; The on-machine calibration device for the cylindrical flat probe as described above is communicatively connected to the machine tool, so as to use the machine tool to obtain the equivalent diameter and calibration length of the cylindrical flat probe to be calibrated, and calibrate the cylindrical flat probe to be calibrated.

[0017] The above technical solution of the present invention has the following beneficial effects compared with the prior art: The on-machine calibration method for the cylindrical flat probe of the present invention, through the means of on-machine measurement by the machine tool, combined with the ring gauge, a precision inspection tool, makes the cylindrical flat probe to be calibrated travel along the generated calibration path, obtains the corresponding actual measurement points, and further directly calculates to obtain the equivalent diameter and length deviation of the cylindrical flat probe to be calibrated, and calibrates the cylindrical flat probe to be calibrated. The present invention directly performs calibration on the machine tool through on-machine measurement, can avoid the errors brought during the production, assembly and use of the probe, and at the same time gets rid of the dependence on the traditional machine tool calibration method. Only by performing corresponding calculations based on the collected actual measurement points can the corresponding calibration data be obtained, which greatly reduces the risk brought by data interaction with the machine tool, facilitates the machine tool operator, improves the accuracy of the measurement results, ensures the calibration accuracy, and further improves the accuracy of the products produced by the cylindrical flat probe; and different numerical control systems can all adopt the calibration method and compensation method of the present invention, and the programming operation method of software calibration is also the same, thus solving the problem of software versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to the specific embodiments of the present invention in conjunction with the drawings, where: Figure 1 is the step flow chart of the on-machine calibration method for the cylindrical flat probe provided by the present invention; Figure 2 Schematic diagram of a flat-bottom cylindrical probe Figure 3 Schematic diagram of a ring gauge Figure 4 Schematic diagram of the measurement path of the inner circular surface group of the ring gauge Figure 5 Schematic diagram of the measurement path of the upper end surface group of the ring gauge Figure 6 Flow chart of calibrating the flat-bottom cylindrical probe in QJCAM provided by the present invention Figure 7 Schematic diagram of a flat-bottom cylindrical probe model Figure 8 Schematic diagram of a ring gauge model Figure 9 Schematic diagram of the composition of the probe calibration module provided by the present invention Figure 10 Schematic diagram of the measurement path provided by the present invention Figure 11 Schematic diagram of placing the ring gauge on the machine table provided by the present invention Figure 12 Schematic diagram of the calibration result of the flat-bottom cylindrical probe provided by the present invention Figure 13 Schematic diagram of the detection results of each measurement point after calibration provided by the present invention Detailed implementation manners

[0019] The present invention will be further described below with reference to 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 given are not intended to limit the present invention.

[0020] Refer to Figure 1 As shown, the step flow chart of the on-machine calibration method for the flat-bottom cylindrical probe provided by the present invention specifically includes the following steps S101: Model the flat-bottom cylindrical probe to be calibrated and the ring gauge to obtain the model of the flat-bottom cylindrical probe to be calibrated and the ring gauge model S102: Based on the model of the flat-bottom cylindrical probe to be calibrated and the ring gauge model, obtain the measurement path of the inner circular surface group of the ring gauge as the radius calibration measurement path, and obtain the measurement path of the upper end surface group of the ring gauge as the length calibration measurement path S103: Place the ring gauge on the machine table and obtain the measurement origin using the reference tool, including Make the reference tool vertically contact the top of the ring gauge to obtain the current position height of the reference tool, which is the Z-axis coordinate of the measurement origin Use the reference tool to obtain the center point of the ring gauge, and use the horizontal and vertical coordinates of the center point of the ring gauge as the X-axis coordinate and Y-axis coordinate of the measurement origin

[0021] S104: Starting from the measurement origin, let the cylindrical flat probe to be calibrated run along the radius calibration measurement path, obtain the relative coordinate values each time the cylindrical flat probe to be calibrated is triggered during the running process, and construct a set of radius measured points; S105: Using the principle of least squares circle fitting, fit all the measured points in the set of radius measured points into a circle, and obtain the fitted center and fitted radius of the fitted circle; S106: Based on the diameter of the ring gauge and the fitted radius, obtain the equivalent diameter of the cylindrical flat probe to be calibrated, expressed as: ; Wherein, represents the equivalent diameter of the cylindrical flat probe to be calibrated, represents the diameter of the ring gauge, represents the fitted radius.

[0022] S107: Starting from the measurement origin, let the cylindrical flat probe to be calibrated run along the length calibration measurement path, obtain the relative coordinate values each time the cylindrical flat probe to be calibrated is triggered during the running process, and construct a set of length measured points; S108: Use the average value of the Z-axis coordinates of all the measured points in the set of length measured points as the length deviation of the cylindrical flat probe to be calibrated, compensate the actual length of the cylindrical flat probe to be calibrated, and obtain the calibrated length; S109: Complete the calibration of the cylindrical flat probe to be calibrated based on the equivalent diameter and calibrated length of the cylindrical flat probe to be calibrated.

[0023] Refer to Figure 2 as shown, it is a schematic diagram of the cylindrical flat probe; refer to Figure 3 as shown, it is a schematic diagram of the ring gauge; refer to Figure 4 as shown, it is a schematic diagram of the measurement path of the inner circular surface group of the ring gauge; refer to Figure 5 as shown, it is a schematic diagram of the measurement path of the upper end surface group of the ring gauge. Specifically, in this embodiment, 3D CAM is used to model the cylindrical flat probe to be calibrated and the ring gauge, obtain the model of the cylindrical flat probe to be calibrated and the model of the ring gauge, and generate the measurement path of the inner circular surface group and the measurement path of the upper end surface group of the ring gauge.

[0024] Specifically, in step S105, using the principle of least squares circle fitting, fit all the measured points in the set of radius measured points into a circle, and obtain the fitted center and fitted radius of the fitted circle, including: S105-1: Define the parametric equation of the fitted circle as: ; S105-2: Based on the measured points in the set of radius measured points, construct an error function , expressed as: ; S105-3: Obtain the parameters when the error function converges using the gradient descent method 、 and , substitute them into the parametric equation of the fitted circle, and obtain the target fitted circle expression as ; Among them, , and respectively represent the X-axis coordinate and Y-axis coordinate of the th measured point in the set of measured points of the radius, , represents the total number of measured points in the set of measured points of the radius.

[0025] S105-4: Obtain the center of the fitted circle of the fitted circle , and the value is: ; S105-5: Obtain the fitted radius of the fitted circle , which is expressed as: .

[0026] Specifically, in step S108, the average value of the Z-axis coordinates of all measured points in the set of measured points of the length is used as the length deviation of the flat-bottom cylindrical probe to be calibrated, and the actual length of the flat-bottom cylindrical probe to be calibrated is compensated to obtain the calibrated length, including: S108-1: Use the average value of the Z-axis coordinates of all measured points in the set of measured points of the length as the length deviation of the flat-bottom cylindrical probe to be calibrated , which is expressed as: ; Among them, represents the Z-axis coordinate of the th measured point in the set of measured points of the length, , represents the total number of measured points in the set of measured points of the length; S108-2: Compensate the actual length of the flat-bottom cylindrical probe to be calibrated to obtain the calibrated length , which is expressed as: ; Among them, represents the actual length of the flat-bottom cylindrical probe to be calibrated.

[0027] The on-machine calibration method of the flat-bottom cylindrical probe described in the present invention calibrates the to-be-calibrated flat-bottom cylindrical probe by means of on-machine measurement of the machine tool, in combination with a precision inspection tool such as a ring gauge. The to-be-calibrated flat-bottom cylindrical probe travels along the generated calibration path to obtain corresponding measured points, and further directly calculates the equivalent diameter and length deviation of the to-be-calibrated flat-bottom cylindrical probe. By means of on-machine measurement, the present invention directly performs calibration on the machine tool, which can avoid the errors brought during the production, assembly and use of the probe, and at the same time gets rid of the dependence on the traditional machine tool calibration method. Only by performing corresponding calculations based on the collected measured points can the corresponding calibration data be obtained, which greatly reduces the risk brought by data interaction with the machine tool, facilitates the machine tool operator, improves the accuracy of the measurement result, ensures the calibration accuracy, and further improves the accuracy of the products produced by the flat-bottom cylindrical probe; moreover, different numerical control systems can adopt the calibration method and compensation method of the present invention, and the programming operation method of software calibration is also the same, thus solving the problem of software versatility.

[0028] Based on the above embodiments, in the embodiments of the present invention, the on-machine calibration method of the flat-bottom cylindrical probe is implemented with the domestically independently developed industrial software QJCAM as the platform; in this embodiment, a Hammer C22 five-axis device is used as the experimental machine tool, a Renishaw 400 probe and a D6 cylindrical probe are selected for the probe, and a ring gauge with an inner diameter of D49.994 is selected for the ring gauge; at the machine tool end, the center XYZ of the ring gauge is found with a standard tool and set as the G54 origin; then, the cylindrical probe is externally tooled and the tool length is input into the tool table. On the software side, first build the probe model in the QJCAM software, select the probe calibration module, and build the ring gauge model in it; add a ring gauge calibration measurement group, and select the machine tool type as a milling machine; start the measurement to obtain the probe calibration result. Refer to Figure 6 As shown, it is the calibration flow chart of the flat-bottom cylindrical probe in QJCAM, and the specific steps include: S201: Build a flat-bottom cylindrical probe model and a ring gauge model in the QJCAM software; Refer to Figure 7 As shown, it is a schematic diagram of the flat-bottom cylindrical probe model; refer to Figure 8 As shown, it is a schematic diagram of the ring gauge model; S202: Select the probe calibration module, set the ring gauge in it, select the corresponding probe, and automatically generate a radius calibration measurement path and a length calibration measurement path according to the probe and the ring gauge model; Refer to Figure 9 As shown, it is a schematic diagram of the composition of the probe calibration module; refer to Figure 10As shown, it is a schematic diagram of the measurement path; among them, the length calibration measurement path is the upper end surface group measurement path, and the upper end surface group measurement path is used to align the length of the flat-bottomed cylindrical probe; the radius calibration measurement path is the inner circle surface group measurement path, and the inner circle surface group measurement path is used to calibrate the radius of the flat-bottomed cylindrical probe.

[0029] S203: After placing the ring gauge on the machine table, use a reference knife to locate the center of the ring gauge and set it as the origin of the measurement program, including: Use the reference cutter to lightly touch the top of the ring gauge and set the current position as the z of the origin G54; Use the reference cutter to find the center of the ring gauge and set it to the xy of the origin G54; Reference Figure 11 The figure shows a schematic diagram of placing the ring gauge on the machine table; S204: Start the QJCAM measurement module, automatically send the ring gauge measurement program to the CNC system, and the machine tool automatically executes the program; after the program is executed, the measurement result is sent back to the QJCAM software so that the QJCAM software can calibrate the radius of the probe according to the measurement result.

[0030] Reference Figure 12 The following is a schematic diagram of the calibration results of a flat-bottomed cylindrical probe; refer to Figure 13 As shown, this is a schematic diagram of the detection results of each measurement point after calibration.

[0031] Specifically, after starting the measurement module, the software first converts the measurement path into a measurement macro program recognized by the CNC system through post-processing of the corresponding machine tool, and sends the measurement macro program to the machine tool through the network cable, and the machine tool executes the program. During the execution of the measurement program, each time the probe is triggered, the relative coordinate value (x 1 ,y 1 ,z 1 ), (x 2 ,y 2 ,z 2 )...... and store these data in the measured points in the relevant "xxxx.txt"; after the measurement is completed, "xxxx.txt" will be sent back to the QJCAM software for processing. The software and the machine tool are connected via a network cable to realize data sending and receiving.

[0032] ① Radius calibration data processing process, including: The least squares circle fitting principle is adopted to fit the multiple measured points into a circle, and the center and radius of the circle are obtained.

[0033] The least squares method is a mathematical optimization technique that finds the best function match for a set of data by minimizing the sum of the squares of the errors. The least squares method uses the simplest method to obtain some absolutely unknown true values and minimizes the sum of the squared errors.

[0034] Based on the previously measured tool tip coordinates (x 1 , y 1 , z 1 ), (x 2 , y 2 , z 2 ),..., these points are fitted to a circle to obtain the radius R, and the diameter D of the known ring gauge. Through the formula D1 = D - 2*R, the equivalent diameter D1 of the probe can be obtained.

[0035] ② The process of processing the length calibration data includes: The formula for calculating the length deviation: ; Compensate this deviation into the existing tool length .

[0036] Thus, the calibration of the probe is completed; the entire process can achieve automated iterative measurement to ensure the accuracy of the calibration result.

[0037] The calibration method of the flat-bottom cylindrical probe based on in-machine measurement by QJCAM in this embodiment can avoid the errors caused by the production, assembly, and installation of the probe through the means of in-machine measurement by the machine tool and in combination with the precision inspection tool of the ring gauge. Thus, the actual radius R of the flat-bottom cylindrical probe and the XY-direction eccentricity can be obtained, realizing the 2D calibration compensation technology of the flat-bottom cylindrical probe at the CNC machine tool end, improving the measurement accuracy during the in-machine use of the flat-bottom cylindrical probe, and meeting the product measurement accuracy requirements. The in-machine measurement software comes with a calibration program for the cylindrical probe, getting rid of the dependence on the machine tool calibration method. It not only greatly reduces the risk brought by the data interaction with the machine tool, facilitating the machine tool operator; but also improves the accuracy of the measurement result, ensuring the accuracy of the in-machine measurement software. At the same time, as a pure domestic software, QJCAM has completely independent and controllable intellectual property rights. The simple operation process, high-precision calibration compensation, and stable and reliable software algorithm promote the extensive and in-depth application of in-machine measurement.

[0038] Based on the above embodiments, the embodiments of the present invention further provide an in-machine calibration device for a flat-bottom cylindrical probe, including: A model construction module for modeling the flat-bottom cylindrical probe to be calibrated and the ring gauge to obtain a model of the flat-bottom cylindrical probe to be calibrated and a ring gauge model; A path generation module, configured to obtain the inner circular surface group measurement path of the ring gauge as the radius calibration measurement path and obtain the upper end surface group measurement path of the ring gauge as the length calibration measurement path based on the flat-bottom cylindrical probe model to be calibrated and the ring gauge model; An origin acquisition module, configured to place the ring gauge on the machine table and use a reference tool to obtain the measurement origin; An equivalent diameter calculation module, configured to start from the measurement origin, make the flat-bottom cylindrical probe to be calibrated run along the radius calibration measurement path, obtain the relative coordinate values each time the flat-bottom cylindrical probe to be calibrated is triggered during the running process, and construct a set of radius measured points; use the least squares circle fitting principle to fit all the measured points in the set of radius measured points into a circle, and obtain the fitting center and fitting radius of the fitting circle; based on the diameter of the ring gauge and the fitting radius, obtain the equivalent diameter of the flat-bottom cylindrical probe to be calibrated; A calibrated length calculation module, configured to start from the measurement origin, make the flat-bottom cylindrical probe to be calibrated run along the length calibration measurement path, obtain the relative coordinate values each time the flat-bottom cylindrical probe to be calibrated is triggered during the running process, and construct a set of length measured points; use the average value of the Z-axis coordinates of all the measured points in the set of length measured points as the length deviation of the flat-bottom cylindrical probe to be calibrated, compensate the actual length of the flat-bottom cylindrical probe to be calibrated, and obtain the calibrated length; A calibration module, configured to complete the calibration of the flat-bottom cylindrical probe to be calibrated based on the equivalent diameter and the calibrated length of the flat-bottom cylindrical probe to be calibrated.

[0039] The in-machine calibration device for the flat-bottom cylindrical probe in this embodiment is used to implement the foregoing in-machine calibration method for the flat-bottom cylindrical probe. Therefore, the specific implementation manner of the in-machine calibration device for the flat-bottom cylindrical probe can be seen in the embodiment part of the in-machine calibration method for the flat-bottom cylindrical probe in the foregoing text. For example, the model construction module, the path generation module, and the origin acquisition module are respectively used to implement steps S101, S102, and S103 in the foregoing in-machine calibration method for the flat-bottom cylindrical probe; the equivalent diameter calculation module is used to implement steps S104, S105, and S106 in the foregoing in-machine calibration method for the flat-bottom cylindrical probe; the calibrated length calculation module is used to implement steps S107 and S108 in the foregoing in-machine calibration method for the flat-bottom cylindrical probe; the calibration module is used to implement step S109 in the foregoing in-machine calibration method for the flat-bottom cylindrical probe. Therefore, its specific implementation manner can be referred to the description of the corresponding various part embodiments and will not be elaborated here.

[0040] Based on the above embodiments, the embodiments of the present invention further provide an in-machine calibration device for a flat-bottom cylindrical probe, including: A machine tool; A flat-bottom cylindrical probe to be calibrated, installed on a preset probe head of the machine tool; A ring gauge, placed on the machine table; The on-machine calibration device for the flat cylindrical probe as described above is communicatively connected to the machine tool so as to utilize the machine tool to obtain the equivalent diameter and calibration length of the flat cylindrical probe to be calibrated and calibrate the flat cylindrical probe to be calibrated.

[0041] The on-machine calibration method for the flat cylindrical probe of the present invention, through the means of on-machine measurement by the machine tool, in combination with a precision inspection tool such as a ring gauge, utilizes the flat cylindrical probe to be calibrated to travel along the generated calibration path to obtain corresponding measured points, and further directly calculates to obtain the equivalent diameter and length deviation of the flat cylindrical probe to be calibrated, and calibrates the flat cylindrical probe to be calibrated. By means of on-machine measurement, the present invention directly calibrates on the machine tool, can avoid the errors brought during the production, assembly and use of the probe, and at the same time gets rid of the dependence on the traditional machine tool calibration method. Only by performing corresponding calculations based on the collected measured points can the corresponding calibration data be obtained, greatly reducing the risk brought by data interaction with the machine tool, facilitating the machine tool operator, and improving the accuracy of the measurement result, ensuring the calibration accuracy, and further improving the accuracy of the products produced by the flat cylindrical probe; and different numerical control systems can all adopt the calibration method and compensation method of the present invention, and the programming operation method of software calibration is also the same, thus solving the problem of software generality.

[0042] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0043] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one or more flows or multiple flows and / or blocks Figure 1 one or more blocks or multiple blocks.

[0044] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction device that implements the functions specified in one or more of the processes and / or blocks Figure 1 one or more of the processes and / or blocks Figure 1 specified in the block or blocks.

[0045] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more of the processes and / or blocks Figure 1 one or more of the processes and / or blocks Figure 1 specified in the block or blocks.

[0046] Obviously, the above embodiments are merely examples for clear illustration and are not limitations on the implementation. For those of ordinary skill 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 exhaustively list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for calibrating a flat-bottomed cylindrical probe on a machine, characterized in that: include: Model the flat-bottomed cylindrical stylus and the ring gauge to be calibrated, and obtain the flat-bottomed cylindrical stylus model and the ring gauge model to be calibrated; Based on the flat-bottomed cylindrical stylus model to be calibrated and the ring gauge model, the inner circle surface group measurement path of the ring gauge is obtained as the radius calibration measurement path, and the upper end surface group measurement path of the ring gauge is obtained as the length calibration measurement path; Place the ring gauge on the machine table and use the reference knife to obtain the measurement origin; Taking the measurement origin as the starting point, the flat-bottomed cylindrical probe to be calibrated is made to run along the radius calibration measurement path, and the relative coordinate value of each time the flat-bottomed cylindrical probe to be calibrated is triggered during the running process is obtained to construct a radius measurement point set; Using the least squares circle fitting principle, all measured points in the radius measured point set are fitted into a circle, and the fitting center and fitting radius of the fitting circle are obtained; Based on the diameter of the ring gauge and the fitting radius, the equivalent diameter of the flat-bottomed cylindrical probe to be calibrated is obtained; Taking the measurement origin as the starting point, the flat-bottomed cylindrical probe to be calibrated is made to run along the length calibration measurement path, and the relative coordinate value of each time the flat-bottomed cylindrical probe to be calibrated is triggered during the running process is obtained to construct a set of length measurement points; The average value of the Z-axis coordinates of all the measured points in the length measured point set is used as the length deviation of the flat-bottomed cylindrical probe to be calibrated, and the actual length of the flat-bottomed cylindrical probe to be calibrated is compensated to obtain the calibration length; The calibration of the flat-bottomed cylindrical stylus to be calibrated is completed based on the equivalent diameter and calibration length of the flat-bottomed cylindrical stylus to be calibrated.

2. The on-machine calibration method for a flat-bottomed cylindrical stylus according to claim 1, characterized in that: The flat-bottomed cylindrical stylus and ring gauge to be calibrated are modeled by 3D CAM, the flat-bottomed cylindrical stylus model and ring gauge model to be calibrated are obtained, and the inner circle surface group measurement path and the upper end surface group measurement path of the ring gauge are generated.

3. The on-machine calibration method for a flat-bottomed cylindrical stylus according to claim 1, characterized in that: Place the ring gauge on the machine table and use the reference knife to obtain the measurement origin, including: Make the reference knife vertically contact the top of the ring gauge, and obtain the current position height of the reference knife, which is the Z-axis coordinate of the measurement origin; Use the reference knife to obtain the center point of the ring gauge, and use the horizontal and vertical coordinates of the center point of the ring gauge as the X-axis coordinate and Y-axis coordinate of the measurement origin.

4. The on-machine calibration method for a flat-bottomed cylindrical stylus according to claim 1, characterized in that: Using the least squares circle fitting principle, all measured points in the radius measured point set are fitted into a circle, including: The parametric equations defining the fitted circle are: ; Based on the measured points in the radius measured point set, the error function is constructed and expressed as: ; Using the gradient descent method, we can get the parameters when the error function converges. , and , substituted into the parameter equation of the fitting circle, the target fitting circle expression is obtained, ; in, , and Respectively represent the radius measured point set The X-axis coordinates and Y-axis coordinates of the measured points, , Represents the total number of measured points in the radius measured point set.

5. The on-machine calibration method for a flat-bottomed cylindrical stylus according to claim 4, characterized in that: Get the fitting center and fitting radius of the fitting circle, including: Get the fitting center of the fitted circle , the value is: ; Get the fitting radius of the fitted circle , expressed as: .

6. The on-machine calibration method for a flat-bottomed cylindrical stylus according to claim 1, characterized in that: Based on the diameter of the ring gauge and the fitting radius, the equivalent diameter of the flat-bottomed cylindrical probe to be calibrated is obtained, expressed as: ； in, represents the equivalent diameter of the flat-bottomed cylindrical stylus to be calibrated, Indicates the diameter of the ring gauge, Represents the fitting radius.

7. The on-machine calibration method for a flat-bottomed cylindrical stylus according to claim 1, characterized in that: The average value of the Z-axis coordinates of all the measured points in the length measurement point set is taken as the length deviation of the flat-bottomed cylindrical probe to be calibrated, which is expressed as: ； in, Indicates the length deviation of the flat-bottomed cylindrical probe to be calibrated. Indicates the length measurement point set The Z-axis coordinates of the measured points, , Indicates the total number of measured points in the length measured point set.

8. The on-machine calibration method for a flat-bottomed cylindrical stylus according to claim 7, characterized in that: The actual length of the flat-bottomed cylindrical probe to be calibrated is added to the length deviation to obtain the calibrated length of the flat-bottomed cylindrical probe to be calibrated, which is expressed as: ； in, Indicates the calibration length of the flat-bottomed cylindrical probe to be calibrated. Indicates the actual length of the flat-bottomed cylindrical stylus to be calibrated.

9. A calibration device based on the on-machine calibration method for a flat-bottomed cylindrical stylus as claimed in any one of claims 1 to 8, characterized in that: include: A model building module is used to model the flat-bottomed cylindrical stylus and the ring gauge to be calibrated, and obtain the flat-bottomed cylindrical stylus model and the ring gauge model to be calibrated; A path generation module is used to obtain the inner circle surface group measurement path of the ring gauge as the radius calibration measurement path, and obtain the upper end surface group measurement path of the ring gauge as the length calibration measurement path based on the flat-bottomed cylindrical stylus model to be calibrated and the ring gauge model; The origin acquisition module is used to place the ring gauge on the machine table and obtain the measurement origin using the reference knife; The equivalent diameter calculation module is used to take the measurement origin as the starting point, make the flat-bottomed cylindrical probe to be calibrated run along the radius calibration measurement path, obtain the relative coordinate value each time the flat-bottomed cylindrical probe to be calibrated is triggered during the running process, and construct a radius measurement point set; use the least squares circle fitting principle to fit all the measured points in the radius measurement point set into a circle, and obtain the fitting center and fitting radius of the fitting circle; based on the diameter and fitting radius of the ring gauge, obtain the equivalent diameter of the flat-bottomed cylindrical probe to be calibrated; The calibration length calculation module is used to take the measurement origin as the starting point, make the flat-bottomed cylindrical probe to be calibrated run along the length calibration measurement path, obtain the relative coordinate value each time the flat-bottomed cylindrical probe to be calibrated is triggered during the running process, and construct a length measurement point set; take the average value of the Z-axis coordinates of all the measured points in the length measurement point set as the length deviation of the flat-bottomed cylindrical probe to be calibrated, compensate for the actual length of the flat-bottomed cylindrical probe to be calibrated, and obtain the calibration length; The calibration module is used for completing the calibration of the flat-bottom cylindrical probe to be calibrated based on the equivalent diameter and calibration length of the flat-bottom cylindrical probe to be calibrated.

10. A flat-bottomed cylindrical stylus on-machine calibration device, characterized in that: include: machine tool; The flat-bottomed cylindrical probe to be calibrated is installed on the preset probe of the machine tool; A ring gauge is placed on the table of the machine; The on-machine calibration device for a flat-bottomed cylindrical stylus as claimed in claim 9 is communicatively connected to the machine tool so as to use the machine tool to obtain the equivalent diameter and calibration length of the flat-bottomed cylindrical stylus to be calibrated, and calibrate the flat-bottomed cylindrical stylus to be calibrated.

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