A method and device for measuring dimensional error of aviation transmission gears

Abstract

The present invention relates to the field of dimension measurement technology, and in particular to a dimension error measurement method and measurement equipment for aviation transmission gears. The present invention obtains the relative coordinates of each gear point and each gear point in the neighborhood according to the position distribution of the corresponding laser points of each gear point and each gear point in the neighborhood under each line laser scan; obtains the relative coordinate confidence of each gear point and each gear point in the neighborhood according to the single point stability index of the corresponding laser points of each gear point and each gear point in the neighborhood under each line laser scan, and the scanning normal factor of the scanning profile; obtains the corrected coordinates of each gear point according to the coordinates and coordinate accuracy of the corresponding laser points of each gear point under different line laser scans; obtains a three-dimensional model of the gear and measures the gear dimension error. The present invention obtains the accurate position coordinates of each gear point, constructs a three-dimensional model of the gear, and improves the accuracy of the gear dimension error measurement.

Description

Technical Field

[0001] The invention relates to the technical field of dimension measurement, and in particular to a dimension error measurement method and a measuring device for an aviation transmission gear. Background Art

[0002] Aviation transmission gears play a vital role in key aviation equipment such as aircraft engines that operate at high speeds. They need to withstand extremely high speeds and loads in working environments, so their precision requirements are extremely high. Minor dimensional errors may lead to reduced efficiency of the transmission mechanism. Therefore, it is necessary to measure the dimensional error of the transmission gear.

[0003] In the prior art, a multi-laser line scanning method is used to measure aviation transmission gears. However, due to the presence of some curved gears in aviation transmission gears, the possibility of being affected by related factors such as laser failure or electromagnetic interference during multi-laser joint measurement increases, which will generate a large amount of error data and reduce the accuracy when measuring dimensional errors. Summary of the invention

[0004] In order to solve the technical problem that the accuracy of measuring dimensional errors is reduced due to the increased possibility of being affected by related factors such as laser failure or electromagnetic interference when multiple lasers are measured together, the purpose of the present invention is to provide a dimensional error measurement method and measuring equipment for aviation transmission gears. The technical solutions adopted are as follows:

[0005] The present invention provides a method for measuring the dimensional error of an aviation transmission gear, the method comprising:

[0006] Acquire the laser point corresponding to each gear point of the aviation transmission gear during different line laser scanning to form the scanning profile of different line laser scanning;

[0007] According to the position distribution of laser points on each scanning profile, the laser interference points on each scanning profile are screened out; according to the number of different scanning profiles where the laser points at the same position are located and the number of corresponding laser interference points, the single-point stability index of each laser point at the same position is obtained; according to the position change trend of different laser points in each scanning profile, the scanning normal factor of each scanning profile is obtained;

[0008] According to the position distribution of the laser points corresponding to each gear point and each gear point in the neighborhood under each line laser scan, the relative coordinates of each gear point and each gear point in the neighborhood under each line laser scan are obtained; according to the single point stability index of the laser points corresponding to each gear point and each gear point in the neighborhood under each line laser scan, and the scanning normal factor of the scanning profile, the relative coordinate confidence of each gear point and each gear point in the neighborhood under each line laser scan is obtained;

[0009] According to the relative coordinates and relative coordinate confidence of each gear point and each gear point in the neighborhood under different line laser scans, the coordinate accuracy of each gear point under each line laser scan is obtained; according to the coordinates and coordinate accuracy of the corresponding laser point of each gear point under different line laser scans, the corrected coordinates of each gear point are obtained;

[0010] According to the corrected coordinates of all gear points, the three-dimensional model of the gear is obtained and the gear size error is measured.

[0011] Furthermore, the method for acquiring the laser interference point includes:

[0012] According to the position distribution of the laser points on each scanning profile, the single point scanning anomaly degree of each laser point on each scanning profile is obtained;

[0013] If the single-point scanning anomaly of each laser point on each scanning contour is greater than the preset anomaly threshold, the corresponding laser point is used as a laser interference point.

[0014] Furthermore, the method for obtaining the single-point scanning abnormality includes:

[0015] Obtain the relative distances between the coordinates of each laser point and the adjacent laser points on each scanning contour, and select the minimum value of the relative distance as the first eigenvalue;

[0016] Obtaining the average of the relative distances between different adjacent laser points on each scanning profile as the second eigenvalue;

[0017] The difference between the first eigenvalue and the second eigenvalue is obtained and normalized as the single-point scanning anomaly degree of each laser point on each scanning profile.

[0018] Furthermore, the method for obtaining the single point stability index includes:

[0019] The ratio of the number of laser interference points corresponding to each laser point at the same position to the number of scanning contours is obtained, and negative correlation mapping is performed as a single-point stability index of each laser point at the same position.

[0020] Furthermore, the method for obtaining the scanning normal factor includes:

[0021] For any scanning profile, the coordinates of the laser points are arranged from front to back, and the coordinate difference between each laser point and the previous adjacent laser point is obtained as the coordinate displacement corresponding to each laser point;

[0022] The scanning factor is obtained according to the scanning normal factor acquisition formula, and the scanning normal factor acquisition formula is expressed as:

[0023] ;in, Indicates Scan normalization factor for each scan profile; Indicates The first scan profile The coordinate displacement corresponding to each laser point; Indicates The first scan profile The coordinate displacement corresponding to each laser point; Indicates The first scan profile The coordinate displacement corresponding to each laser point; Represents the standard deviation calculation function; represents an exponential function with a natural constant as base; Indicates taking the absolute value; Indicates The number of laser points on a scan profile.

[0024] Furthermore, the relative coordinate acquisition method includes:

[0025] The coordinate difference in the horizontal direction between each gear point under each line laser scan and the corresponding laser point of each gear point in the neighborhood is obtained as the relative coordinate of each gear point under each line laser scan and each gear point in the neighborhood.

[0026] Furthermore, the method for obtaining the relative coordinate confidence includes:

[0027] Calculate the single-point stability index of each gear point and the laser point corresponding to each gear point in the neighborhood under each line laser scan, as well as the product of the scanning normal factor of the scanning profile, select the minimum value of the product result, and perform negative correlation mapping as the relative coordinate error degree;

[0028] The difference between the positive integer 1 and the relative coordinate error degree is obtained as the relative coordinate confidence of each gear point and each gear point in the neighborhood under each line laser scan.

[0029] Furthermore, the method for obtaining the coordinate accuracy includes:

[0030] According to the relative coordinate confidence of each gear point and each gear point in the neighborhood under different line laser scanning, the relative coordinates are weighted averaged to obtain the relative weighted coordinates of each gear point and each gear point in the neighborhood;

[0031] The coordinate accuracy is obtained according to the coordinate accuracy acquisition formula, which is expressed as:

[0032] ;in, Indicates Line laser scanning Coordinate accuracy of each gear point; Indicates The gear point and the Relative weighted coordinates of the gear points; Indicates Line laser scanning The gear point and the The relative coordinates of the gear points; Indicates all line laser scans Next The gear point and the A discrete sequence of relative coordinates of gear points; Indicates all lines of laser scanning The gear point and the The standard deviation of the relative coordinates of the gear points; Indicates the number of gear points within the neighborhood; Represents an exponential function with a natural constant as its base.

[0033] Furthermore, the method for obtaining the corrected coordinates includes:

[0034] According to the coordinate accuracy of the laser point corresponding to each gear point under different line laser scanning, the coordinates of the laser point are weighted averaged as the corrected coordinates of each gear point.

[0035] The present invention also proposes a measuring device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of any one of the methods for measuring the dimensional error of an aviation transmission gear are implemented.

[0036] The present invention has the following beneficial effects:

[0037] The present invention screens out laser interference points on each scanning profile according to the position distribution of laser points on each scanning profile, which is helpful to remove abnormal data points caused by other interference factors; obtains a single-point stability index of each laser point at the same position according to the number of different scanning profiles where the laser point at the same position is located and the number of corresponding laser interference points, reflecting the stability and consistency of the laser point in different scanning profiles; obtains a scanning normal factor of each scanning profile according to the position change trend of different laser points in each scanning profile, reflecting the overall change trend and stability of the scanning profile; obtains the relative coordinates of each gear point and each gear point in the neighborhood under each line laser scan according to the position distribution of the corresponding laser points of each gear point and each gear point in the neighborhood under each line laser scan, reflecting the relative position relationship between the gear point and the gear points in its neighborhood; The single point stability index of each gear point and the corresponding laser point of each gear point in the neighborhood under line laser scanning, as well as the scanning normal factor of the scanning profile, are used to obtain the relative coordinate confidence of each gear point and each gear point in the neighborhood under each line laser scanning, providing a quantitative evaluation for the accuracy of the relative coordinates; the coordinate accuracy of each gear point under each line laser scanning is obtained according to the relative coordinates and relative coordinate confidence of each gear point and each gear point in the neighborhood under different line laser scanning, reflecting the overall accuracy of the gear point coordinates; the corrected coordinates of each gear point are obtained according to the coordinates and coordinate accuracy of the corresponding laser point of each gear point under different line laser scanning, and the accuracy and consistency of the gear point coordinates are improved by comprehensively considering the results of multiple scanning data; the three-dimensional model of the gear is obtained according to the corrected coordinates of all gear points, and the gear size error is measured. The present invention obtains the accurate position coordinates of each gear point, constructs a three-dimensional model of the gear, and improves the accuracy of the gear size error measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A flow chart of a method for measuring dimensional error of an aviation transmission gear provided by one embodiment of the present invention;

[0040] Figure 2 A flow chart of a method for obtaining single-point scanning abnormality provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the dimension error measurement method and measuring equipment of an aviation transmission gear proposed by the present invention, its specific implementation method, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0042] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0043] The following is a detailed description of a method and device for measuring the dimensional error of an aviation transmission gear provided by the present invention in conjunction with the accompanying drawings.

[0044] See also Figure 1 , which shows a method flow chart of a method for measuring the dimensional error of an aviation transmission gear provided by an embodiment of the present invention, specifically comprising:

[0045] Step S1: Acquire the laser points corresponding to each gear point when the aviation transmission gear is subjected to different line laser scanning, and form the scanning profiles of different line laser scanning.

[0046] In an embodiment of the present invention, taking into account the scanning errors that may be caused by partial laser instrument failure or electromagnetic interference during line laser scanning, the characteristics of the gear under different line laser scanning are analyzed; first, the aviation transmission gear is placed on a special fixture of the measuring equipment, and then multiple line lasers are started to scan the gear. During scanning, multiple laser lines are evenly distributed at different positions of the gear such as the tooth top, tooth root, and tooth surface. At the same time, the gear rotates at a preset three revolutions per minute to ensure that all parts of the gear can be scanned by the laser line, and the laser points corresponding to each gear point of the aviation transmission gear during different line laser scanning are obtained to form scanning profiles of different line laser scanning; wherein, each gear point can obtain different coordinate positions during different line laser scanning, that is, the coordinate position of the corresponding laser point.

[0047] Step S2: According to the position distribution of the laser points on each scanning profile, the laser interference points on each scanning profile are screened out; according to the number of different scanning profiles where the laser points at the same position are located and the number of corresponding laser interference points, the single-point stability index of each laser point at the same position is obtained; according to the position change trend of different laser points in each scanning profile, the scanning normal factor of each scanning profile is obtained.

[0048] When the laser points on the line laser are scanning the gears, under normal circumstances, the distribution of the laser points is relatively neat, and the distances between the laser points are roughly the same; on the contrary, when the distribution of a laser point does not conform to this rule, it means that the laser point is faulty at this time, so according to the position distribution of the laser points on each scanning contour, the laser interference points on each scanning contour are screened out.

[0049] Preferably, in one embodiment of the present invention, the method for acquiring the laser interference point includes:

[0050] According to the position distribution of the laser points on each scanning profile, the single point scanning anomaly degree of each laser point on each scanning profile is obtained;

[0051] Preferably, in one embodiment of the present invention, the method for obtaining the single-point scanning abnormality degree can be found in Figure 2 , which shows a flow chart of a method for obtaining a single-point scanning abnormality, including:

[0052] Step S201: respectively obtain the relative distances between the coordinates of each laser point and the adjacent laser points on each scanning contour, and select the minimum value of the relative distance as the first eigenvalue.

[0053] The relative distance between adjacent laser points can reflect the local details of the scanning profile. The smaller the distance, the closer the distribution, and the more normal the laser performance.

[0054] It should be noted that, in one embodiment of the present invention, the method for obtaining the relative distance between the laser points is to calculate the distance between the coordinates of the laser points by using existing distance calculation methods such as Euclidean distance or Manhattan distance. The specific means are technical means well known to those skilled in the art and will not be described in detail here.

[0055] Step S202: Obtain the average of the relative distances between different adjacent laser points on each scanning profile as the second eigenvalue.

[0056] The relative distances between all adjacent laser points on each scan profile were analyzed by averaging to evaluate the overall trend level of the scan profile.

[0057] Step S203: Obtain the difference between the first eigenvalue and the second eigenvalue, and normalize it as the single-point scanning anomaly of each laser point on each scanning profile.

[0058] In one embodiment of the present invention, the formula for the single-point scanning abnormality is expressed as:

[0059]

[0060] in, Indicates The first scan profile Single point scanning anomaly of laser points; Indicates The first scan profile The next adjacent laser point The relative distance between Indicates The first scan profile The next adjacent laser point The relative distance between Indicates The average of the relative distances between different adjacent laser points on the scanning profile is the second eigenvalue; Represents the minimum value function; represents an exponential function with a natural constant as base; represents the hyperbolic tangent function; Indicates taking the absolute value.

[0061] In the formula of single-point scanning anomaly, Indicates the first The first scan profile The next adjacent laser point The relative distance between the next adjacent laser point The minimum value of the relative distance between them is the first eigenvalue; It represents the difference between the first eigenvalue and the second eigenvalue. The smaller the difference is, the closer the distance between the laser points is, and the smaller the scanning abnormality is.

[0062] If the single-point scanning anomaly of each laser point on each scanning contour is greater than the preset anomaly threshold, the corresponding laser point is used as a laser interference point.

[0063] It should be noted that, in one embodiment of the present invention, the preset abnormality threshold is 0.4; in other embodiments of the present invention, the size of the preset abnormality threshold can be set according to the specific situation, and is not limited or elaborated here.

[0064] A single scan cannot evaluate whether the laser point is an accidental abnormality or a problem with the laser source. By analyzing the number of laser interference points under different scanning profiles, the overall trend of the scanning quality can be understood. Based on the number of different scanning profiles where the laser point at the same position is located and the number of corresponding laser interference points, the single-point stability index of each laser point at the same position is obtained.

[0065] Preferably, in one embodiment of the present invention, the method for obtaining a single-point stability index includes:

[0066] The ratio of the number of laser interference points corresponding to each laser point at the same position to the number of scanning contours is obtained, and negative correlation mapping is performed as a single-point stability index of each laser point at the same position.

[0067] In one embodiment of the present invention, the formula of the single point stability index is expressed as:

[0068] ;

[0069] in, Indicates each laser point at the same position Single point stability indicator; Indicates each laser point at the same position The number of corresponding laser interference points; Indicates each laser point at the same position The number of scan profiles.

[0070] In the formula of the single point stability index, Indicates each laser point at the same position The ratio of the number of corresponding laser interference points to the number of scanning contours. The larger the ratio, the more corresponding laser interference points there are, the more likely there is a problem with the laser, and the worse the single-point stability index.

[0071] When scanning gears, when the line laser scans on multiple planes, its scanning profile is a plurality of straight line segments of different heights; when it scans a curved surface, the scanning profile presents a relatively neat curved segment; therefore, when the line laser scanning is not disturbed, the differences between the coordinates of each point on the scanning profile are roughly equal or relatively stable, and the degree of interference to the scanning profile is evaluated by analyzing the position change trend of different laser points; therefore, the scanning normal factor of each scanning profile is obtained according to the position change trend of different laser points in each scanning profile.

[0072] Preferably, in one embodiment of the present invention, the method for obtaining the scanning normal factor includes:

[0073] For any scanning profile, the coordinates of the laser points are arranged from front to back, and the coordinate difference between each laser point and the previous adjacent laser point is obtained as the coordinate displacement corresponding to each laser point;

[0074] The scanning factor is obtained according to the scanning normal factor acquisition formula, and the scanning normal factor acquisition formula is expressed as:

[0075] ;

[0076] in, Indicates Scan normalization factor for each scan profile; Indicates The first scan profile The coordinate displacement corresponding to each laser point; Indicates The first scan profile The coordinate displacement corresponding to each laser point; Indicates The first scan profile The coordinate displacement corresponding to each laser point; Represents the standard deviation calculation function; represents an exponential function with a natural constant as base; Indicates taking the absolute value; Indicates The number of laser points on a scan profile.

[0077] In the formula for scanning the normal factor, the exponential function with the natural constant as the base is used to convert Perform negative correlation mapping; Indicates The first scan profile The laser point and The difference between the corresponding coordinate displacements is the displacement difference; The ratio of the previous displacement difference to the next displacement difference is expressed as a first ratio, and the first ratios corresponding to different laser points are obtained; It represents the standard deviation of all first ratios corresponding to the scan profile. The larger the standard deviation, the smaller the fluctuation degree of the change, the relatively stable changes between adjacent ones, and the larger the scan normal factor.

[0078] Step S3: According to the position distribution of the laser points corresponding to each gear point and each gear point in the neighborhood under each line laser scan, the relative coordinates of each gear point and each gear point in the neighborhood are obtained; according to the single point stability index of each gear point and the laser points corresponding to each gear point in the neighborhood under each line laser scan, and the scanning normal factor of the scanning profile, the relative coordinate confidence of each gear point and each gear point in the neighborhood under each line laser scan is obtained.

[0079] Since each line laser is at a different angle, the coordinates of each gear point scanned need to be changed and compared. By analyzing the position distribution of each gear point and the gear points in the neighborhood, the calculation of relative coordinates is more accurate, and the shape and size of the gear can be determined more accurately. According to the position distribution of the corresponding laser points of each gear point and each gear point in the neighborhood under each line laser scan, the relative coordinates of each gear point and each gear point in the neighborhood under each line laser scan are obtained.

[0080] Preferably, in one embodiment of the present invention, the method for obtaining relative coordinates includes:

[0081] The coordinate difference in the horizontal direction between each gear point under each line laser scan and the corresponding laser point of each gear point in the neighborhood is obtained as the relative coordinate of each gear point under each line laser scan and each gear point in the neighborhood.

[0082] It should be noted that, in one embodiment of the present invention, the neighborhood range is a range consisting of eight adjacent gear points based on each gear point, which does not include the base gear point itself; in other embodiments of the present invention, the neighborhood range can be set according to specific circumstances, and is not limited or elaborated herein.

[0083] The single-point stability index reflects the stability of each gear point under laser scanning, evaluates the reliability of each laser point, and then determines the confidence of its coordinates; the scanning normal factor reflects the accuracy and normality of the entire scanning profile, and is used to evaluate the overall quality of the scanning profile, thereby determining the coordinate confidence of each point therein, and comprehensively evaluating the single-point stability index and the scanning normal factor to evaluate the relative coordinate confidence of each gear point. According to the single-point stability index of each gear point and the corresponding laser point of each gear point in the neighborhood under each line laser scan, and the scanning normal factor of the scanning profile, the relative coordinate confidence of each gear point and each gear point in the neighborhood under each line laser scan is obtained.

[0084] Preferably, in one embodiment of the present invention, the method for obtaining relative coordinate confidence comprises:

[0085] Calculate the single-point stability index of each gear point and the laser point corresponding to each gear point in the neighborhood under each line laser scan, as well as the product of the scanning normal factor of the scanning profile, select the minimum value of the product result, and perform negative correlation mapping as the relative coordinate error degree;

[0086] The difference between the positive integer 1 and the relative coordinate error degree is obtained as the relative coordinate confidence of each gear point and each gear point in the neighborhood under each line laser scan.

[0087] In one embodiment of the present invention, the formula for relative coordinate confidence is expressed as:

[0088] ;

[0089] in, Indicates Line laser scanning The gear point and the Relative coordinate confidence of each gear point; Indicates Line laser scanning The scanning normal factor of the scanning contour where the laser point is located corresponding to each gear point; Indicates Line laser scanning The single-point stability index of each gear point corresponding to the laser point; Indicates Line laser scanning within the neighborhood The scanning normal factor of the scanning contour where the laser point is located corresponding to each gear point; Indicates Line laser scanning The single-point stability index of each gear point corresponding to the laser point; Represents the minimum value function; Represents an exponential function with a natural constant as its base.

[0090] In the formula for relative coordinate confidence, By using an exponential function with a natural constant as the base Perform negative correlation mapping, i.e., the relative coordinate error degree; Indicates Line laser scanning The product of the scanning normal factor and the single-point stability index of the scanning contour corresponding to the laser point at each gear point, Indicates Line laser scanning within the neighborhood The product of the scanning normal factor and the single-point stability index of the scanning contour corresponding to the laser point at each gear point, Select The product corresponding to the gear point and the The gear point corresponds to the minimum value in the product. The smaller the minimum value, the greater the relative coordinate error and the smaller the relative coordinate confidence.

[0091] Step S4: According to the relative coordinates and relative coordinate confidence of each gear point and each gear point in the neighborhood under different line laser scans, the coordinate accuracy of each gear point under each line laser scan is obtained; according to the coordinates and coordinate accuracy of the laser point corresponding to each gear point under different line laser scans, the corrected coordinates of each gear point are obtained.

[0092] The relative coordinates describe the positional relationship of each gear point relative to other gear points in its neighborhood. The relative coordinate confidence reflects the reliability of the relative coordinate measurement. The larger the relative coordinate confidence, the more accurate the coordinate data. The coordinate accuracy of each gear point under each line laser scan is obtained based on the relative coordinates and relative coordinate confidence of each gear point and each gear point in the neighborhood under different line laser scans.

[0093] Preferably, in one embodiment of the present invention, the method for obtaining coordinate accuracy includes:

[0094] According to the relative coordinate confidence of each gear point and each gear point in the neighborhood under different line laser scanning, the relative coordinates are weighted averaged to obtain the relative weighted coordinates of each gear point and each gear point in the neighborhood;

[0095] The coordinate accuracy is obtained according to the coordinate accuracy acquisition formula, which is expressed as:

[0096] ;

[0097] in, Indicates Line laser scanning Coordinate accuracy of each gear point; Indicates The gear point and the Relative weighted coordinates of the gear points; Indicates Line laser scanning The gear point and the The relative coordinates of the gear points; Indicates all line laser scans Next The gear point and the A discrete sequence of relative coordinates of gear points; Indicates all lines of laser scanning The gear point and the The standard deviation of the relative coordinates of the gear points; Indicates the number of gear points within the neighborhood; Represents an exponential function with a natural constant as its base.

[0098] In the formula for obtaining coordinate accuracy, the exponential function with the natural constant as the base is used to convert Perform negative correlation mapping; Indicates The gear point and the The difference between the relative weighted coordinates and the relative coordinates of the gear points, It represents the ratio of the difference to the standard deviation, that is, the difference is standardized. The larger the difference, the larger the relative weighted coordinate of the gear point as a whole. The larger the difference between the relative weighted coordinate and the relative coordinate, the smaller the coordinate accuracy. The smaller the difference between the relative weighted coordinate and the relative coordinate, the greater the coordinate accuracy.

[0099] The coordinate accuracy reflects the accuracy of the relative coordinates, that is, the reference size of the coordinates. By integrating the data under multiple different line laser scans and weighting them using the coordinate accuracy, the deviation can be effectively reduced and the overall measurement accuracy can be improved. The corrected coordinates of each gear point are obtained based on the coordinates and coordinate accuracy of the laser point corresponding to each gear point under different line laser scans.

[0100] Preferably, in one embodiment of the present invention, the method for obtaining the corrected coordinates includes:

[0101] According to the coordinate accuracy of each gear point corresponding to the laser point under different line laser scanning, the coordinates of the laser points are weighted averaged as the corrected coordinates of each gear point.

[0102] It should be noted that the product of the coordinate accuracy of the laser point corresponding to each gear point under each line laser scan and the coordinate of the laser point is calculated as the first product; the average of the first products under all line laser scans is obtained as the corrected coordinates of each gear point.

[0103] Step S5: According to the corrected coordinates of all gear points, a three-dimensional model of the gear is obtained, and the gear size error is measured.

[0104] The three-dimensional model can intuitively display the shape, structure and characteristics of the gear; through the three-dimensional model, it is easier to identify problems such as gear geometric shape deviation and surface defects to ensure gear quality.

[0105] It should be noted that, in the embodiment of the present invention, based on the corrected coordinates of all gear points, the least squares fitting or The algorithm fits all the gear points to obtain a three-dimensional model of the gear; after obtaining the three-dimensional model, the gear-related parameters such as the number of teeth, tooth width, tooth top height, tooth top circle diameter, etc. can be obtained, and then the gear size error can be obtained by comparing the actual measured size of the gear with the design parameters; for the tooth profile error, the tooth profile error can be evaluated in the normal direction of the involute. The specific means are technical means well known to those skilled in the art and will not be elaborated here.

[0106] In summary, the present invention obtains the relative coordinates of each gear point and each gear point in the neighborhood according to the position distribution of the corresponding laser points of each gear point and each gear point in the neighborhood under each line laser scan; obtains the relative coordinate confidence of each gear point and each gear point in the neighborhood according to the single point stability index of each gear point and the corresponding laser point of each gear point in the neighborhood under each line laser scan, and the scanning normal factor of the scanning profile; obtains the corrected coordinates of each gear point according to the coordinates and coordinate accuracy of the corresponding laser point of each gear point under different line laser scans; obtains the three-dimensional model of the gear, and measures the gear size error. The present invention obtains the accurate position coordinates of each gear point, constructs a three-dimensional model of the gear, and improves the accuracy of the gear size error measurement.

[0107] The present invention also proposes a measuring device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements any one of the steps of a method for measuring the dimensional error of an aviation transmission gear.

[0108] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0109] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A method for measuring the dimensional error of an aviation transmission gear, characterized in that: The method comprises: Acquire the laser point corresponding to each gear point of the aviation transmission gear during different line laser scanning to form the scanning profile of different line laser scanning; According to the position distribution of laser points on each scanning profile, the laser interference points on each scanning profile are screened out; according to the number of different scanning profiles where the laser points at the same position are located and the number of corresponding laser interference points, the single-point stability index of each laser point at the same position is obtained; according to the position change trend of different laser points in each scanning profile, the scanning normal factor of each scanning profile is obtained; According to the position distribution of the laser points corresponding to each gear point and each gear point in the neighborhood under each line laser scan, the relative coordinates of each gear point and each gear point in the neighborhood under each line laser scan are obtained; according to the single point stability index of the laser points corresponding to each gear point and each gear point in the neighborhood under each line laser scan, and the scanning normal factor of the scanning profile, the relative coordinate confidence of each gear point and each gear point in the neighborhood under each line laser scan is obtained; According to the relative coordinates and relative coordinate confidence of each gear point and each gear point in the neighborhood under different line laser scans, the coordinate accuracy of each gear point under each line laser scan is obtained; according to the coordinates and coordinate accuracy of the corresponding laser point of each gear point under different line laser scans, the corrected coordinates of each gear point are obtained; According to the corrected coordinates of all gear points, the three-dimensional model of the gear is obtained and the gear size error is measured.

2. The method for measuring the dimensional error of an aviation transmission gear according to claim 1, characterized in that: The method for obtaining the laser interference point includes: According to the position distribution of the laser points on each scanning profile, the single point scanning anomaly degree of each laser point on each scanning profile is obtained; If the single-point scanning anomaly of each laser point on each scanning contour is greater than the preset anomaly threshold, the corresponding laser point is used as a laser interference point.

3. The method for measuring the dimensional error of an aviation transmission gear according to claim 2, characterized in that: The method for obtaining the single-point scanning abnormality degree includes: Obtain the relative distances between the coordinates of each laser point and the adjacent laser points on each scanning contour, and select the minimum value of the relative distance as the first eigenvalue; Obtaining the average of the relative distances between different adjacent laser points on each scanning profile as the second eigenvalue; The difference between the first eigenvalue and the second eigenvalue is obtained and normalized as the single-point scanning anomaly degree of each laser point on each scanning profile.

4. The method for measuring the dimensional error of an aviation transmission gear according to claim 1, characterized in that: The method for obtaining the single point stability index includes: The ratio of the number of laser interference points corresponding to each laser point at the same position to the number of scanning contours is obtained, and negative correlation mapping is performed as a single-point stability index of each laser point at the same position.

5. The method for measuring the dimensional error of an aviation transmission gear according to claim 1, characterized in that: The method for obtaining the scanning normal factor includes: For any scanning profile, the coordinates of the laser points are arranged from front to back, and the coordinate difference between each laser point and the previous adjacent laser point is obtained as the coordinate displacement corresponding to each laser point; The scanning factor is obtained according to the scanning normal factor acquisition formula, and the scanning normal factor acquisition formula is expressed as: ;in, Indicates Scan normalization factor for each scan profile; Indicates The first scan profile The coordinate displacement corresponding to each laser point; Indicates The first scan profile The coordinate displacement corresponding to each laser point; Indicates The first scan profile The coordinate displacement corresponding to each laser point; Represents the standard deviation calculation function; represents an exponential function with a natural constant as base; Indicates taking the absolute value; Indicates The number of laser points on a scan profile.

6. The method for measuring the dimensional error of an aviation transmission gear according to claim 1, characterized in that: The method for obtaining the relative coordinates includes: The coordinate difference in the horizontal direction between each gear point under each line laser scan and the corresponding laser point of each gear point in the neighborhood is obtained as the relative coordinate of each gear point under each line laser scan and each gear point in the neighborhood.

7. The method for measuring the dimensional error of an aviation transmission gear according to claim 1, characterized in that: The method for obtaining the relative coordinate confidence comprises: Calculate the single-point stability index of each gear point and the laser point corresponding to each gear point in the neighborhood under each line laser scan, as well as the product of the scanning normal factor of the scanning profile, select the minimum value of the product result, and perform negative correlation mapping as the relative coordinate error degree; The difference between the positive integer 1 and the relative coordinate error degree is obtained as the relative coordinate confidence of each gear point and each gear point in the neighborhood under each line laser scan.

8. The method for measuring the dimensional error of an aviation transmission gear according to claim 1, characterized in that: The method for obtaining the coordinate accuracy includes: According to the relative coordinate confidence of each gear point and each gear point in the neighborhood under different line laser scanning, the relative coordinates are weighted averaged to obtain the relative weighted coordinates of each gear point and each gear point in the neighborhood; The coordinate accuracy is obtained according to the coordinate accuracy acquisition formula, which is expressed as: ;in, Indicates Line laser scanning Coordinate accuracy of each gear point; Indicates The gear point and the Relative weighted coordinates of the gear points; Indicates Line laser scanning The gear point and the The relative coordinates of the gear points; Indicates all line laser scans Next The gear point and the A discrete sequence of relative coordinates of gear points; Indicates all lines of laser scanning The gear point and the The standard deviation of the relative coordinates of the gear points; Indicates the number of gear points within the neighborhood; Represents an exponential function with a natural constant as its base.

9. The method for measuring the dimensional error of an aviation transmission gear according to claim 1, characterized in that: The method for obtaining the corrected coordinates includes: According to the coordinate accuracy of the laser point corresponding to each gear point under different line laser scanning, the coordinates of the laser point are weighted averaged as the corrected coordinates of each gear point.

10. A measuring device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for measuring the dimensional error of an aviation transmission gear as described in any one of claims 1 to 9 are implemented.

Images