Workpiece three-coordinate measurement automatic error dynamic compensation method and system

Abstract

The invention discloses a workpiece three-coordinate measurement automatic error dynamic compensation method and system, and relates to the technical field of measurement error compensation. The method includes the steps that roughness data of a measurement point are obtained for the first time, and an initial information item is obtained and used for expressing the workpiece surface roughness degree within a target measurement point range; initial three-coordinate data of the target workpiece are obtained based on the result of the first measurement, initial data items are obtained, and the initial data items comprise the three-coordinate data of all the target measurement points and are used for feeding back specific specification data of the target workpiece. According to the method, the comprehensive roughness is obtained by obtaining the roughness data and the calculation result of the measurement point, the initial three-coordinate data of the workpiece is obtained based on the first measurement result, the dynamic roughness is obtained based on the dynamic data, and the compensation adjustment item and the initial data item are combined based on the positive and negative relation of the dynamic difference value. Therefore, the dynamic compensation effect on the error is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of measurement error compensation, and in particular to a method and system for automatic error dynamic compensation of three-coordinate measurement of a workpiece. Background Art

[0002] The three-coordinate system of a workpiece refers to a coordinate system used to describe the position and posture of a workpiece in three-dimensional space. It is usually used for processing, measurement and control. The workpiece is generally measured using contact measurement, laser measurement, optical measurement and other methods. Due to the three-coordinate measurement of the workpiece, the three-coordinate measuring instrument itself may have errors in mechanics, thermal expansion and contraction, sensor sensitivity, etc., which will affect the accuracy of the measurement results. Therefore, error compensation is required. Error compensation can be improved through calibration and adjustment to improve measurement accuracy. Common error compensation methods include temperature compensation, geometric error compensation, calibration compensation and software compensation.

[0003] The patent publication number is CN108692644A, which is a three-coordinate measurement device and error compensation method for complex curved surfaces. A three-coordinate measurement device composed of a three-degree-of-freedom motion platform and a force-controlled probe is designed, and the specific structure and arrangement of the force-controlled probe are studied and designed, so that a force control part is added to the three-coordinate measurement, so that the probe and the workpiece surface always maintain constant force contact during measurement, and the measured data can truly reflect the contour information of the workpiece surface. A six-dimensional force sensor is used to collect the contact force on the probe, and the direction of the error compensation of the probe ball head radius is estimated by the force direction, thereby improving the measurement accuracy. A spring and a micro-grating ruler are added to the force-controlled probe, which can effectively reduce the vibration generated when rigid bodies are in direct contact with rigid bodies, and can effectively measure the tiny displacement of the probe when it is in contact with the workpiece surface, so as to further ensure the measurement accuracy. An error compensation method based on force feedback information is proposed, which realizes three-dimensional measurement of complex curved surfaces based on the data measured by the six-dimensional force sensor and the micro-grating ruler, and realizes real-time compensation of the measurement data during the measurement process, thereby greatly improving the measurement accuracy.

[0004] When the above-mentioned and similar technical solutions perform three-coordinate measurement on the workpiece, the measurement accuracy will be affected by the flatness of the workpiece surface. Therefore, it is necessary to perform error compensation for the flatness of the workpiece surface. However, the flatness of the workpiece surface is divided into normal flatness and dynamic flatness. Normal flatness is a flat state that will not change during the entire measurement process, while dynamic flatness will change with the progress of the measurement process or different measurements. For example, under the influence of vibration, temperature difference and other conditions, the flatness of the workpiece surface will be affected. Therefore, it is necessary to adjust the error compensation scheme and compensation value in real time according to the change in the flatness of the material surface to prevent the error compensation from failing to meet the real-time changes of the workpiece, resulting in poor measurement accuracy. Summary of the invention

[0005] The object of the present invention is to provide a method and system for automatic error dynamic compensation of workpiece three-coordinate measurement to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method and system for automatic error dynamic compensation of workpiece three-coordinate measurement, comprising:

[0007] The roughness data of the measuring point is obtained for the first time to obtain an initial information item, and the initial information item is used to represent the surface roughness of the workpiece within the range of the target measuring point;

[0008] Based on the result of the first measurement, initial three-coordinate data of the target workpiece is obtained to obtain initial data items, which include three-coordinate data of each target measurement point and are used to feed back specific specification data of the target workpiece;

[0009] Setting an acquisition interval, continuously acquiring roughness data of each measuring point based on the acquisition interval, obtaining roughness dynamic data of the target measuring point, and obtaining a dynamic data item, the dynamic data item being used to represent roughness change data corresponding to the target measuring point during the acquisition interval;

[0010] Acquire dynamic roughness based on the dynamic data item, and acquire dynamic difference based on the difference between the dynamic data item and the initial information item, the dynamic difference being used to represent the roughness change difference of the target measuring point of the target workpiece during the measuring process;

[0011] A rough data item is obtained based on the ratio of the initial information item to the initial data item. The rough data item is three-coordinate data corresponding to the percentage value of the roughness of the workpiece surface. A compensation adjustment item is obtained based on the ratio of the dynamic difference to the rough data item. The compensation adjustment item is the compensation value required based on the dynamic difference as a benchmark. Based on the positive and negative relationship of the dynamic difference, the compensation adjustment item is combined with the initial data item. Error compensation is performed through an adjustment method, thereby realizing dynamic compensation of the error.

[0012] Furthermore, the initial information items include arithmetic mean roughness, root mean square roughness and maximum height difference, and the acquisition method includes:

[0013] S1: first range setting, setting the first acquisition range, taking the measurement point as the center, and obtaining the first acquisition range items based on the acquisition range division;

[0014] S2: Project setting: based on the first acquisition range item, at least two feature points are set, the feature points are distributed within the acquisition range, and height data of the feature points are acquired to obtain a first feature height set;

[0015] S3: Arithmetic mean roughness acquisition, based on the acquisition formula:

[0016] ;

[0017] in represents the height of the i-th measurement point, represents the average height of all measurement points, Indicates the total number of measurement points. The smaller the value, the smoother the surface, which is suitable for parts that require high-precision fit;

[0018] S4: Root mean square roughness acquisition, based on the acquisition formula:

[0019] ;

[0020] in Provides another measure of surface roughness, similar to It can better reflect the impact of extreme altitude;

[0021] S5: Maximum height difference acquisition, based on the acquisition formula:

[0022] ;

[0023] ;

[0024] ;

[0025] To select quantity, The value is used to indicate the amount of protrusions or depressions on the surface and is suitable for applications where extreme surface topography needs to be considered. and Used to represent the average height of feature points. and Feature points used to represent the target quantity.

[0026] Furthermore, the method for obtaining roughness data of the measuring point includes:

[0027] M1: First weight setting, setting the first information proportion weight, respectively allocated to the initial information items, the first information proportion weight is used to reflect the importance of each indicator in a specific application;

[0028] M2: Overall roughness acquisition, based on the acquisition formula:

[0029] ;

[0030] Taking all factors into consideration, a comprehensive evaluation result is given to facilitate comparison between different surfaces. , as well as The information weight is set.

[0031] Furthermore, the method for obtaining the initial data items includes: based on the target measurement point and measurement requirements, the measurement requirements include position requirements and length requirements, matching the target corresponding point for the target measurement point based on the measurement requirements, and obtaining the initial data items based on the initial three-coordinate data difference between the target corresponding point and the target measurement point. The initial data items are used to feedback specific specification data of the target workpiece.

[0032] Furthermore, the method for obtaining the dynamic difference includes:

[0033] Based on the acquisition formula:

[0034] ;

[0035] in is the roughness difference corresponding to the vth acquisition interval, is the roughness corresponding to the vth acquisition interval, It is the initial information item.

[0036] Furthermore, the initial information item also includes the skewness of the surface profile and the kurtosis of the surface profile, and the acquisition method includes:

[0037] S6: Obtaining the skewness of the surface profile, based on the acquisition formula:

[0038] ;

[0039] in, Used to identify trends in surface features, represents the height of the i-th measurement point, represents the average height of all measurement points, Indicates the total number of measurement points. is obtained for the root mean square roughness;

[0040] S7: Surface profile peak acquisition, based on the acquisition formula:

[0041] ;

[0042] Higher values ​​indicate sharper surface features, whereas lower values ​​indicate sharper surface features. A value of 0 indicates smooth surface features.

[0043] Furthermore, the method for obtaining roughness data of the measuring point includes:

[0044] Z1: Second weight setting, set the second information proportion weight, and allocate it to the initial information items respectively. The second information proportion weight is used to reflect the importance of each indicator in a specific application;

[0045] Z2: Overall roughness acquisition, based on the acquisition formula:

[0046] ;

[0047] Taking all factors into consideration, a comprehensive evaluation result is given to facilitate comparison between different surfaces. , , , as well as The information weight is set.

[0048] Furthermore, the adjustment method includes: when the dynamic difference is a positive number, it means that the roughness dynamic data of the target measurement point is greater than the initial roughness data of the measurement point. At this time, the dynamic difference is a positive number and positive adjustment is required. When the dynamic difference is a negative number, it means that the roughness dynamic data of the target measurement point is less than the initial roughness data of the measurement point. At this time, the dynamic difference is a negative number and reverse adjustment is required. The adjustment amount is the compensation adjustment item.

[0049] Furthermore, a workpiece three-coordinate measurement automatic error dynamic compensation system uses the above-mentioned workpiece three-coordinate measurement automatic error dynamic compensation method, which is composed of an acquisition module, a calculation module, a comparison module and a compensation module, wherein:

[0050] Acquisition module: acquires the roughness data of the measuring point for the first time. When the target workpiece is measured for the first time, the data in the measurement process are all initial information, and the measuring point at the first measurement is used as the benchmark. The roughness data is used to indicate the surface roughness of the workpiece within the range of the target measurement point.

[0051] Calculation module: according to the arithmetic mean roughness calculation formula, the root mean square roughness calculation formula and the maximum height calculation formula, the arithmetic mean roughness, the root mean square roughness and the maximum height are obtained respectively, and combined into the overall roughness;

[0052] Comparison module: Continuously obtain the roughness data of each measuring point based on the acquisition interval, obtain the dynamic difference based on the difference between the dynamic data item and the initial information item, obtain the rough data item based on the ratio of the initial information item to the initial data item, the rough data item is the three-coordinate data corresponding to the percentage value of the roughness of the workpiece surface, and obtain the compensation adjustment item based on the ratio of the dynamic difference to the rough data item;

[0053] Compensation module: Based on the dynamic difference as a benchmark, the compensation value needs to be made, and based on the positive and negative relationship of the dynamic difference, the compensation adjustment item and the initial data item are combined. When the dynamic difference is a positive number, positive adjustment is performed, and when the dynamic difference is a negative number, negative adjustment is performed.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The method and system for automatic dynamic compensation of errors in three-coordinate measurement of a workpiece obtain roughness data of a measuring point, calculate the result to obtain comprehensive roughness, obtain initial three-coordinate data of the workpiece based on the result of the first measurement, set an acquisition interval, continuously obtain roughness data of each measuring point based on the acquisition interval, obtain dynamic roughness based on dynamic data, and combine compensation adjustment items with initial data items based on the positive and negative relationship of dynamic difference values, thereby achieving a dynamic compensation effect for errors. In the actual measurement process of the workpiece, the error compensation value is adjusted in real time according to the real-time dynamic changes of the workpiece, so as to reduce the error as much as possible and improve the accuracy of error compensation.

[0056] At the same time, the comprehensive roughness includes data such as arithmetic mean roughness, root mean square roughness, maximum height difference, skewness of surface profile and peak state of surface profile. A weight ratio is assigned to each data, and the comprehensive roughness is combined according to the comprehensive calculation results of each data to make the result of the comprehensive roughness more detailed. When there are slight changes in the workpiece during the measurement process, the comprehensive roughness of the workpiece can be quickly and accurately obtained, which improves the accuracy of obtaining the comprehensive roughness of the workpiece, thereby improving the accuracy of error compensation for the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0058] Figure 2 It is a schematic diagram of the relationship between the characteristic points and the measurement points of the present invention;

[0059] Figure 3 It is a schematic diagram of the measurement point positions of the present invention. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] When performing three-dimensional coordinate measurement, the impact of the flatness of the workpiece surface on the measurement accuracy cannot be ignored. In order to obtain accurate measurement results, error compensation for the flatness of the workpiece surface has become an indispensable technology. The change in flatness can be divided into two types: normal flatness and dynamic flatness. Normal flatness means that the flatness of the workpiece surface remains unchanged during the entire measurement process. This flatness is usually the ideal state after processing and can provide a stable benchmark for the measurement process. However, in reality, it is often difficult for the workpiece surface to achieve the ideal normal flatness due to various conditions such as material properties, processing accuracy, and environmental factors. Under this premise, continuous monitoring and evaluation of the workpiece surface is particularly important. Only when the surface condition of the workpiece is fully understood can the corresponding Error compensation strategy is used to improve the accuracy of measurement. Dynamic flatness is opposite to normal flatness, which refers to the real-time changes of the workpiece surface during the measurement process. This change may be caused by external factors, such as vibration, temperature change, humidity fluctuation, etc. Vibration is undoubtedly an important factor affecting dynamic flatness. During mechanical processing or transportation, the workpiece is easily vibrated, which leads to changes in its surface state. In addition, changes in temperature difference can also affect the physical properties of the material, causing the flatness of the workpiece surface to be disturbed. The influence of these dynamic factors makes it possible for the actual state of the workpiece to differ significantly from the ideal state in three-coordinate measurement. In order to cope with these dynamic changes, the error compensation scheme and its value must be adjusted in real time during the three-coordinate measurement process. Specifically, in this application, Figure 1 As shown, the steps include S100-S400.

[0062] Step S100: acquiring roughness data of a measuring point for the first time to obtain an initial information item.

[0063] It should be noted that when the target workpiece is measured for the first time, the data in the measurement process are all initial information, and the measurement point at the first measurement is used as a reference. The roughness data is used to indicate the surface roughness of the workpiece within the target measurement point range.

[0064] Specifically, the method for acquiring roughness data of a measuring point includes steps S1001 - S1006 .

[0065] Step S1001: first range setting, setting a first acquisition range, taking the measurement point as the center, and obtaining first acquisition range items based on acquisition range division.

[0066] It should be noted that the first acquisition range is set to 10% of the area of ​​the target surface of the target workpiece. First, the area data of the target surface of the target workpiece is obtained, and the first acquisition range is set based on 10% of the area data. The first acquisition range is a circular area with the measuring point as the center to obtain the first acquisition range item.

[0067] Step S1002: Based on the first acquisition range item, at least two feature points are set, the feature points are distributed within the acquisition range, and height data of the feature points are acquired to obtain a first feature height set.

[0068] like Figure 2 As shown, it should be noted that the number of feature points set is 10, the feature points are distributed within the first acquisition range, and the height data of each feature point is obtained by laser ranging and other distance measurement methods to obtain the first feature height set.

[0069] Step S1003: Acquisition of arithmetic mean roughness.

[0070] It should be noted that the formula for obtaining the arithmetic mean roughness is:

[0071] ;

[0072] in represents the height of the i-th measurement point, represents the average height of all measurement points, Indicates the total number of measurement points. The smaller the value, the smoother the surface, which is suitable for parts that require high-precision fit.

[0073] In the specific implementation process, the target surface area of ​​the target workpiece is obtained to be 10 square centimeters. At this time, according to the set first acquisition range, the target surface of the target workpiece is divided with the measuring point as the center and an area of ​​1 square centimeter as the first acquisition range, and according to the set number of feature points, 10 feature points are distributed in the first acquisition range, and the heights of the 10 feature points are obtained respectively. The height data obtained are: 5.2μm, 5.0μm, 5.1μm, 4.9μm, 5.2μm, 5.3μm, 5.0μm, 4.8μm, 5.1μm and 5.0μm. At this time, the arithmetic average roughness is calculated according to the arithmetic average roughness acquisition formula. First, the average height is calculated. ;

[0074] At this time, the arithmetic mean roughness is:

[0075] ;

[0076] The calculated result is 0.026.

[0077] Step S1004: acquiring root mean square roughness.

[0078] It should be noted that the formula for obtaining the root mean square roughness is:

[0079] ;

[0080] in Provides another measure of surface roughness, similar to It can better reflect the impact of extreme altitude.

[0081] In the specific implementation process, the calculation is performed based on the height data of the 10 feature points obtained above, and the root mean square roughness is:

[0082] ;

[0083] The calculated result is 0.155.

[0084] Step S1005: obtaining the maximum height difference.

[0085] It should be noted that the formula for obtaining the maximum height difference is:

[0086] ;

[0087] ;

[0088] ;

[0089] at this time is 5.3, is 4.8, the number of choices is 5, the average of the top 5 values ​​is selected, and the result is calculated is 1.036, is 0.97, so 1.036+0.97=2.006

[0090] Step S1006: acquiring roughness data.

[0091] It should be noted that after obtaining the arithmetic mean roughness, root mean square roughness and maximum height difference, the overall roughness is obtained by setting the weight of the first information ratio. The formula for obtaining the overall roughness is:

[0092] ;

[0093] , as well as is the set information weight, and the set information weights are =0.33, =0.33, =0.33, at this time, according to the overall roughness acquisition formula, it is calculated that S=0.33*0.026+0.33*0.0155+0.33*2.006=0.77.

[0094] Step S200: based on the result of the first measurement, initial three-coordinate data of the target workpiece is obtained to obtain initial data items, which include three-coordinate data of each target measurement point and are used to feed back specific specification data of the target workpiece.

[0095] It should be noted that, during the initial measurement, the initial three-coordinate information of the target workpiece can be obtained through the three-coordinate data of each measuring point, and then the initial data items are obtained. The initial data items are obtained in the following ways: based on the target measurement point and measurement requirements, the measurement requirements include position requirements and length requirements, matching the target measurement point with the target corresponding point based on the measurement requirements, and obtaining the initial data items based on the difference between the initial three-coordinate data of the target corresponding point and the target measurement point. The initial data items are used to feedback the specific specification data of the target workpiece.

[0096] like Figure 3 As shown, in the specific implementation process, a total of 6 measuring points are set for the target workpiece, among which the three-coordinate data of measuring point No. 1 is (0, 2, 4), the three-coordinate data of measuring point No. 2 is (6, 2, 4), the three-coordinate data of measuring point No. 3 is (0, 4, 0), the three-coordinate data of measuring point No. 4 is (0, 4, 4), the three-coordinate data of measuring point No. 5 is (3, 0, 4), and the three-coordinate data of measuring point No. 6 is (3, 0, 0). At this time, according to the measurement requirements, it is determined that the distance between measuring point No. 1 and measuring point No. 2 is the length data of the workpiece, the distance between measuring point No. 3 and measuring point No. 4 is the width data of the workpiece, and the distance between measuring point No. 5 and measuring point No. 6 is the height data of the workpiece, that is, the target corresponding point of measuring point No. 1 is measuring point No. 2, the target corresponding point of measuring point No. 3 is measuring point No. 4, and the target corresponding point of measuring point No. 5 is measuring point No. 6, thereby obtaining the initial data item.

[0097] Step S300: setting an acquisition interval, continuously acquiring roughness data of each measuring point based on the acquisition interval, obtaining roughness dynamic data of the target measuring point, and obtaining a dynamic data item, which is used to represent the roughness change data corresponding to the target measuring point during the acquisition interval.

[0098] It should be noted that the acquisition interval is set to 10s, and the roughness data of each measuring point is continuously acquired based on the acquisition interval, that is, based on the acquisition interval, the roughness data of each measuring point is repeatedly acquired to obtain the roughness dynamic data of each measuring point.

[0099] In the specific implementation process, at the first acquisition interval, according to the set number of feature points, 10 feature points are distributed in the first acquisition range, and the heights of the 10 feature points are obtained respectively. The obtained height data are: 5.2μm, 5.0μm, 5.0μm, 4.8μm, 5.1μm, 5.2μm, 4.9μm, 4.7μm, 5.0μm and 4.9μm. At this time, the arithmetic average roughness is calculated according to the arithmetic average roughness acquisition formula. First, the average height is calculated. ;

[0100] ;

[0101] At this time, the arithmetic mean roughness is:

[0102] ;

[0103] The calculated result is 0.128.

[0104] Root mean square roughness acquisition.

[0105] It should be noted that the formula for obtaining the root mean square roughness is:

[0106] ;

[0107] Calculated based on the height data of the 10 feature points obtained above, the root mean square roughness is:

[0108] ;

[0109] The calculated result is 0.152.

[0110] Get the maximum height difference.

[0111] It should be noted that the formula for obtaining the maximum height difference is:

[0112] ;

[0113] ;

[0114] ;

[0115] at this time is 5.1, is 5.0, the number of choices is 5, the average of the top 5 values ​​is selected, and the result is calculated is 1.02, is 1, so 1.02+1=2.02

[0116] Roughness data acquisition.

[0117] It should be noted that after obtaining the arithmetic mean roughness, root mean square roughness and maximum height difference, the overall roughness is obtained by setting the weight of the first information ratio. The formula for obtaining the overall roughness is:

[0118] ;

[0119] , as well as is the set information weight, and the set information weights are =0.33, =0.33, =0.33, at this time, according to the overall roughness acquisition formula, it is calculated that S=0.33*0.128+0.33*0.152+0.33*2.02=0.78.

[0120] Step S400: A dynamic difference is obtained based on the difference between the dynamic data item and the initial information item, and a rough data item is obtained based on the ratio of the initial information item to the initial data item. The rough data item is three-coordinate data corresponding to the percentage value of the roughness of the workpiece surface. A compensation adjustment item is obtained based on the ratio of the dynamic difference to the rough data item. The compensation adjustment item is a compensation value that needs to be made based on the dynamic difference as a reference. Based on the positive and negative relationship of the dynamic difference, the compensation adjustment item is combined with the initial data item, and error compensation is performed through an adjustment method, thereby realizing dynamic compensation of the error, including steps S4001-S4002.

[0121] In the specific implementation process, a total of 2 measuring points are set for the target workpiece, where the three-coordinate data of the first measuring point is (0, 2, 4), and the three-coordinate data of the second measuring point is (6, 2, 4). At this time, the length data of the target workpiece is 6 cm. Based on the above results, the dynamic difference is 0.78-0.0.77=0.01. The acquisition result of the rough data item is the ratio of the initial information item to the initial data item, that is:

[0122] 0.77 / 6=0.128. Since the dynamic difference is 0.01, the compensation adjustment item is the ratio of the dynamic difference to the rough data item, that is, 0.01 / 0.128=0.078. Since the dynamic difference is a positive number, positive adjustment is required at this time, that is, the error adjustment value is 0.078.

[0123] The roughness data of the measuring point is obtained through the combined results of the arithmetic mean roughness, the root mean square roughness and the maximum height difference, and the basic data is obtained by setting multiple feature points. When the basic data changes slightly, the roughness data of the measuring point will also change to a certain extent under the combined results of the arithmetic mean roughness, the root mean square roughness and the maximum height difference, and the specific change value of the roughness data of the measuring point can be successfully obtained according to the data change, and then the error is compensated according to the percentage of the change in the value, so that the error compensation is more accurate and the acquisition of the value is more convenient, so the error compensation of the target measuring point can be quickly located.

[0124] In the specific implementation process, dynamic error compensation is performed on three workpieces, which are marked as workpiece A, workpiece B, and workpiece C. The initial detection results show that the length of workpiece A is 10 cm, the length of workpiece B is 9 cm, and the length of workpiece C is 15 cm. The dynamic roughness data of workpiece A, workpiece B, and workpiece C are obtained respectively for error compensation. The results are shown in Table 1:

[0125] Table 1:

[0126] ;

[0127] The comparison between the actual measurement results and the compensation amount shows that the error of workpiece A is shortened from 0.285 to 0.001, the error of workpiece B is shortened from 0.15 to 0.017, and the error of workpiece C is shortened from 0.17 to 0.001, and the errors are significantly reduced.

[0128] Step S4001: Obtaining the skewness of the surface profile.

[0129] It should be noted that the skewness of the surface profile can also be used as a measure of surface features. The formula for obtaining the skewness of the surface profile is:

[0130] ;

[0131] in Used to identify trends in surface features, represents the height of the i-th measurement point, represents the average height of all measurement points, Indicates the total number of measurement points. is obtained for the root mean square roughness.

[0132] Step S4002: Acquire the peak state of the surface profile.

[0133] It should be noted that the formula for obtaining the peak state of the surface profile is:

[0134] ;

[0135] Higher values ​​indicate sharper surface features, whereas lower values ​​indicate sharper surface features. A value of 0 indicates smooth surface features.

[0136] In the specific implementation process, when the measurement point is taken as the center and the area is 1 square centimeter as the first acquisition range, the target surface of the target workpiece is divided, and according to the set number of feature points, 10 feature points are distributed in the first acquisition range, and the heights of the 10 feature points are obtained as follows: 5.2μm, 5.0μm, 5.1μm, 4.9μm, 5.2μm, 5.3μm, 5.0μm, 4.8μm, 5.1μm and 5.0μm. At this time, according to the formula:

[0137] ;

[0138] ;

[0139] To calculate the skewness of the surface profile, first calculate

[0140] ;

[0141] After calculation, the absolute value of the skewness of the surface profile is obtained to be 1.151.

[0142] Again, calculate the kurtosis of the surface profile, first by calculating:

[0143] ;

[0144] After calculation, the peak value of the surface profile is 3.677.

[0145] It should be noted that when considering the skewness acquisition of the surface profile and the kurtosis acquisition of the surface profile, it is necessary to reset the information weight and set the second information weight, which is allocated to the initial information items respectively. The second information weight is used to reflect the importance of each indicator in the specific application. At this time, the overall roughness acquisition formula is:

[0146] ;

[0147] , , , as well as The information weight is set.

[0148] In the specific implementation process, the information weight is set to 0.2. At this time, the overall roughness is calculated according to the formula:

[0149] =0.2*0.128+0.2*0.152+0.2*2.02+0.2*1.151+0.2*3.377=3.292.

[0150] By acquiring the roughness data of the measuring points, the comprehensive roughness is obtained by calculating the results, and the initial three-coordinate data of the workpiece is obtained based on the result of the first measurement. By setting the acquisition interval, the roughness data of each measuring point is continuously acquired based on the acquisition interval, the dynamic roughness is obtained based on the dynamic data, and the dynamic difference is obtained based on the difference between the dynamic data item and the initial information item. The rough data item is obtained based on the ratio of the initial information item to the initial data item, and the compensation adjustment item is obtained based on the ratio of the dynamic difference to the rough data item. Based on the positive and negative relationship of the dynamic difference, the compensation adjustment item is combined with the initial data item, thereby achieving a dynamic compensation effect for the error. Since the comprehensive roughness includes data such as arithmetic mean roughness, root mean square roughness, maximum height difference, skewness of the surface profile, and peak state of the surface profile, each data is assigned a weight ratio, and the comprehensive roughness is combined according to the comprehensive calculation results of each data, so that the result of the comprehensive roughness is more detailed. When there is a slight change in the workpiece measurement process, the comprehensive roughness of the workpiece can also be quickly and accurately obtained, thereby improving the accuracy of obtaining the comprehensive roughness of the workpiece.

[0151] A workpiece three-coordinate measurement automatic error dynamic compensation system uses the above-mentioned workpiece three-coordinate measurement automatic error dynamic compensation method, and is composed of an acquisition module, a calculation module, a comparison module and a compensation module, wherein:

[0152] Acquisition module: acquires the roughness data of the measuring point for the first time. When the target workpiece is measured for the first time, the data in the measurement process are all initial information, and the measuring point at the first measurement is used as the benchmark. The roughness data is used to indicate the surface roughness of the workpiece within the range of the target measurement point.

[0153] Calculation module: according to the arithmetic mean roughness calculation formula, the root mean square roughness calculation formula and the maximum height calculation formula, the arithmetic mean roughness, the root mean square roughness and the maximum height are obtained respectively, and combined into the overall roughness;

[0154] Comparison module: Continuously acquire roughness data of each measuring point based on the acquisition interval, obtain roughness dynamic data of the target measuring point, obtain dynamic roughness based on the dynamic data item, obtain dynamic difference based on the difference between the dynamic data item and the initial information item, obtain rough data item based on the ratio of the initial information item to the initial data item, the rough data item is three-coordinate data corresponding to the percentage value of the roughness of the workpiece surface, and obtain compensation adjustment item based on the ratio of the dynamic difference to the rough data item;

[0155] Compensation module: Based on the dynamic difference as a benchmark, the compensation value needs to be made, and based on the positive and negative relationship of the dynamic difference, the compensation adjustment item and the initial data item are combined. When the dynamic difference is a positive number, positive adjustment is performed, and when the dynamic difference is a negative number, negative adjustment is performed.

[0156] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the attached embodiments and their equivalents.

Claims

1. A method for automatic error dynamic compensation of workpiece three-coordinate measurement, characterized in that: include: The roughness data of the measuring point is obtained for the first time to obtain an initial information item, and the initial information item is used to represent the surface roughness of the workpiece within the range of the target measuring point; Based on the result of the first measurement, initial three-coordinate data of the target workpiece is obtained to obtain initial data items, which include three-coordinate data of each target measurement point and are used to feed back specific specification data of the target workpiece; Setting an acquisition interval, continuously acquiring roughness data of each measuring point based on the acquisition interval, obtaining roughness dynamic data of the target measuring point, and obtaining a dynamic data item, the dynamic data item being used to represent roughness change data corresponding to the target measuring point during the acquisition interval; Acquire dynamic roughness based on the dynamic data item, and acquire dynamic difference based on the difference between the dynamic data item and the initial information item, the dynamic difference being used to represent the roughness change difference of the target measuring point of the target workpiece during the measuring process; A rough data item is obtained based on the ratio of the initial information item to the initial data item. The rough data item is three-coordinate data corresponding to the percentage value of the roughness of the workpiece surface. A compensation adjustment item is obtained based on the ratio of the dynamic difference to the rough data item. The compensation adjustment item is the compensation value required based on the dynamic difference as a benchmark. Based on the positive and negative relationship of the dynamic difference, the compensation adjustment item is combined with the initial data item. Error compensation is performed through an adjustment method, thereby realizing dynamic compensation of the error.

2. The method for automatic error dynamic compensation of workpiece three-coordinate measurement according to claim 1, characterized in that: The initial information items include arithmetic mean roughness, root mean square roughness and maximum height difference, and the acquisition method includes: S1: first range setting, setting a first acquisition range, taking the measurement point as the center, and obtaining first acquisition range items based on the first acquisition range division; S2: Item setting: based on the first acquisition range item, at least two feature points are set, the feature points are distributed within the first acquisition range, and height data of the feature points are acquired to obtain a first feature height set; S3: Arithmetic mean roughness acquisition, based on the acquisition formula: ， in represents the height of the i-th measurement point, represents the average height of all measurement points, Indicates the total number of measurement points. The smaller the value, the smoother the surface, which is suitable for parts that require high-precision fit; S4: Root mean square roughness acquisition, based on the acquisition formula: ； in Provides another measure of surface roughness, similar to It better reflects the impact of extreme altitude; S5: Maximum height difference acquisition, based on the acquisition formula: ； ； ； To select quantity, The value is used to indicate the amount of protrusions or depressions on the surface and is suitable for applications where extreme surface morphology needs to be considered. and Used to represent the average height of feature points. and Feature points used to represent the number of targets, Indicates is the height of the feature point of the reference, Indicates The height of the feature point of the reference.

3. The method for automatic error dynamic compensation of workpiece three-coordinate measurement according to claim 2 is characterized in that: The method for obtaining roughness data of the measuring point comprises: M1: First weight setting, setting the first information proportion weight, respectively allocated to the initial information items, the first information proportion weight is used to reflect the importance of each indicator in a specific application; M2: Overall roughness acquisition, based on the acquisition formula: ； It is the initial information item, taking various factors into consideration, and gives a comprehensive evaluation result to facilitate the comparison between different surfaces. , as well as The information weight is set.

4. The method for automatic error dynamic compensation of workpiece three-coordinate measurement according to claim 1, characterized in that: The method for obtaining the initial data item includes: based on the target measurement point and measurement requirements, the measurement requirements include position requirements and length requirements, matching the target measurement point with the target corresponding point based on the measurement requirements, and obtaining the initial data item based on the initial three-coordinate data difference between the target corresponding point and the target measurement point, and the initial data item is used to feedback the specific specification data of the target workpiece.

5. The method for automatic error dynamic compensation of workpiece three-coordinate measurement according to claim 1, characterized in that: The method for obtaining the dynamic difference includes: Based on the acquisition formula: ； in is the roughness difference corresponding to the vth acquisition interval, is the roughness corresponding to the vth acquisition interval, It is the initial information item.

6. The method for automatic error dynamic compensation of workpiece three-coordinate measurement according to claim 3, characterized in that: The initial information item also includes the skewness of the surface profile and the kurtosis of the surface profile, and the acquisition method includes: S6: Obtaining the skewness of the surface profile, based on the acquisition formula: ； in, Used to identify trends in surface features, represents the height of the i-th measurement point, represents the average height of all measurement points, Indicates the total number of measurement points. is obtained for the root mean square roughness; S7: Surface profile peak acquisition, based on the acquisition formula: ； Higher values ​​indicate sharper surface features, whereas lower values ​​indicate sharper surface features. A value of 0 indicates smooth surface features.

7. The method for automatic error dynamic compensation of workpiece three-coordinate measurement according to claim 6, characterized in that: The method for obtaining roughness data of the measuring point comprises: Z1: Second weight setting, set the second information proportion weight, and allocate it to the initial information items respectively. The second information proportion weight is used to reflect the importance of each indicator in a specific application; Z2: Overall roughness acquisition, based on the acquisition formula: ； It is the initial information item, taking various factors into consideration, and gives a comprehensive evaluation result to facilitate the comparison between different surfaces. , , , as well as The information weight is set.

8. The method for automatic error dynamic compensation of workpiece three-coordinate measurement according to claim 1, characterized in that: The adjustment method includes: when the dynamic difference is a positive number, it means that the roughness dynamic data of the target measurement point is greater than the initial roughness data of the measurement point. At this time, the dynamic difference is a positive number and positive adjustment is required. When the dynamic difference is a negative number, it means that the roughness dynamic data of the target measurement point is less than the initial roughness data of the measurement point. At this time, the dynamic difference is a negative number and reverse adjustment is required. The adjustment amount is a compensation adjustment item.

9. A workpiece three-coordinate measurement automatic error dynamic compensation system, characterized in that: A method for automatic error dynamic compensation of three-coordinate measurement of a workpiece according to any one of claims 1 to 8 is used, which is composed of an acquisition module, a calculation module, a comparison module and a compensation module, wherein: Acquisition module: acquires the roughness data of the measuring point for the first time. When the target workpiece is measured for the first time, the data in the measurement process are all initial information, and the measuring point at the first measurement is used as the benchmark. The roughness data is used to indicate the surface roughness of the workpiece within the range of the target measurement point. Calculation module: according to the arithmetic mean roughness calculation formula, the root mean square roughness calculation formula and the maximum height calculation formula, the arithmetic mean roughness, the root mean square roughness and the maximum height are obtained respectively, and combined into the overall roughness; Comparison module: Continuously obtain the roughness data of each measuring point based on the acquisition interval, obtain the dynamic difference based on the difference between the dynamic data item and the initial information item, obtain the rough data item based on the ratio of the initial information item to the initial data item, the rough data item is the three-coordinate data corresponding to the percentage value of the roughness of the workpiece surface, and obtain the compensation adjustment item based on the ratio of the dynamic difference to the rough data item; Compensation module: Based on the dynamic difference as a benchmark, the compensation value needs to be made, and based on the positive and negative relationship of the dynamic difference, the compensation adjustment item and the initial data item are combined. When the dynamic difference is a positive number, positive adjustment is performed, and when the dynamic difference is a negative number, negative adjustment is performed.

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