Pin head appearance profile detection method and profile, tooth spacing, cross bar distance evaluation method

Abstract

The application discloses a tenon appearance profile detection method and a profile degree, tooth distance and cross-bar distance evaluation method in the technical field of turbine blade detection of an aero-engine. The four-axis coordinate device and the confocal spectrum sensor are used to realize spatial scanning and data point collection of the tenon appearance profile, non-contact detection of the tenon appearance profile can be realized, the actual profile of the tenon appearance profile is obtained, the detection efficiency is higher, meanwhile, the tenon surface is not damaged, high-precision and high-efficiency detection of the tenon appearance profile is realized, the current tenon measurement adopts manual operation, the precision is not high, and the tenon measurement cannot be digitized, and the like, the defects are made up, and the detection requirements of the large size curvature, high precision and complex evaluation parameters of the tenon of the aero-engine blade can be met simultaneously.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of turbine blade detection of an aero-engine, in particular to a tenon topography profile detection method and a profile, pitch and cross-bar distance evaluation method. BACKGROUND

[0002] The turbine working blade (hereinafter referred to as turbine blade) of an aero-engine is a key component of the aero-engine and is a key structural part that withstands high-speed rotation, high temperature and high pressure and complex stress environment, and the quality thereof directly affects the reliability, safety and performance of the engine.

[0003] A large number of fir tree tenon (hereinafter referred to as tenon) structures are used in the aero-engine to connect the turbine disc and the blade, which is due to the small size, multiple contact surfaces, high strength and easy maintenance of the fir tree structure.

[0004] The turbine blade tenon has the characteristics of high machining precision under high temperature, high pressure and high load in work, and the geometric structure profile thereof is complex, and the detection of part sizes requires high precision, such as the precision requirement of the working surface part ≤9μm, and the tolerance band shows a continuous change trend. In the actual manufacturing process, the tenon part is usually machined by using high-precision profile grinding technology.

[0005] At present, there are technologies for scanning the tenon profile by using a contact detection method such as a three-coordinate measuring machine, a profilometer and a small measuring needle, which must be customized to have a diameter of 0.5mm in order to complete the scanning task, and the scanning speed is generally not more than 2mm / s. The physical rigidity of the small measuring needle is poor, the precision loss is serious, and the precision and efficiency cannot meet the requirements of tenon detection. At the same time, the small measuring needle is basically equivalent to a needle tip structure, and there is a risk of scratching the surface of the part.

[0006] Based on this, the present application designs a tenon topography profile detection method and a profile, pitch and cross-bar distance evaluation method to solve the above problems. SUMMARY

[0007] To achieve the above purpose, the present application provides the following technical scheme: a tenon topography profile detection method using a 4-axis coordinate device and a confocal spectral sensor to realize tenon profile scanning collection and non-contact optical detection of spatial points, including the following steps:

[0008] S1, focal length error compensation and indication error compensation of the confocal spectral sensor;

[0009] S2, converting the theoretical data of the tenon topography profile into a theoretical data set of the tenon topography profile;

[0010] The theoretical data of the tenon topography profile includes a theoretical profile and a tolerance band curve;

[0011] The theoretical data set includes the theoretical values, upper tolerance and lower tolerance data of the points on the theoretical contour;

[0012] S3, refer to the aviation blade tenon coordinate system establishment specification to establish the tenon coordinate system;

[0013] S4, after the optical parameters of the confocal spectral sensor are adjusted, a non-contact optical scanning of the tenon profile is performed to obtain the actual tenon profile.

[0014] As a further solution of the present invention, in step S2, when the theoretical data of the tenon profile does not contain a complete tolerance band curve, it is necessary to obtain a complete tolerance band curve through a continuous tolerance change transition calculation. The tolerance value of each two adjacent points in the transition area is equal to the ratio of the point distance to the tolerance difference. The specific calculation method is expressed as follows:

[0015]

[0016] Where: x1, x2, y1, y2 represent the X and Y coordinates of each adjacent point, δs represents the distance between two adjacent points, S represents the total distance of all points in the transition area, LT1 and LT2 represent the original tolerance values ​​of the transition area points, and LT' represents the calculated transition tolerance value.

[0017] As a further solution of the present invention, in step S2, each point in the theoretical profile is projected in the vector direction to the upper and lower tolerance zones, the intersection points are calculated one by one, and the distance is calculated to define the tolerance value, and the data is aggregated into a theoretical data set with tolerances in a unified format of X, Y, Z, I, J, K, UT, and LT;

[0018] Among them, X, Y, and Z represent the coordinates of the point, I, J, and K represent the vector of the point, UT represents the upper tolerance, and LT represents the lower tolerance.

[0019] As a further solution of the present invention, in step S3, when establishing the coordinate system of the tenon, a contact probe having a diameter equal to the diameter of the roller is used. The specific method for establishing the coordinate system of the tenon is as follows:

[0020] S31: Use 3D simulated centering to find the center of the stylus on the tenon in the leading and trailing directions. Calculate the coordinates of the roller contact points using trigonometric functions. Four points in total, designated L1, L2, R1, and R2, are used. The tenon trailing edge end face measurement point, X1, is used.

[0021] S32, use the four contact points of the tenon L1, L2, R1, and R2 to calculate the axis of the plane in which they are located, with the orientation being the blade stacking axis and the direction pointing to the blade tip, and establish the Z-axis origin;

[0022] S33, the mid-rail is established using the connection of L1 and L2 and the connection of R1 and R2, the axis is calculated, the direction is towards the blade trailing edge, and the Y-axis origin is established;

[0023] S34, the X origin is established using the X1 point.

[0024] As a further scheme of the present application, in step S4, when the tenon profile is non-contact optically scanned, the tenon profile is symmetrically divided into two parts in the tenon width direction.

[0025] An aero-engine turbine blade tenon profile degree evaluation method, which is suitable for the above-mentioned aero-engine turbine blade tenon profile non-contact detection method, comprises the following steps:

[0026] S51, the actual profile of the tenon profile is divided into an overall profile and a working surface profile;

[0027] S52, the overall profile obtained in step S51 is subjected to overall deviation and fitting processing using the Gauss least square method, and an overall best fitting curve is obtained;

[0028] S53, the working surface profile obtained in step S51 is subjected to deviation and fitting processing using the quadratic Gauss least square method again on the basis of the overall best fitting curve, and a working surface best fitting curve is obtained, the working surface best fitting curve is compared with a tolerance band curve and a theoretical profile, and the tenon profile degree is evaluated.

[0029] An aero-engine turbine blade tenon pitch evaluation method, which is suitable for the above-mentioned aero-engine turbine blade tenon profile non-contact detection method, comprises the following steps:

[0030] S61, the tenon actual profile obtained in step S4 is introduced into tenon analysis software, and two groups of virtual roller circles are established, the diameter of the roller is the theoretical roller diameter required by the technology;

[0031] S62, the virtual roller circles are positioned to the real roller positions in the tenon actual profile, and first group roller lower contact points L1 and R1 and second group roller upper contact points L2 and R2 are obtained;

[0032] S63, the center line LINE1 of the first group roller and the midpoint O1, and the center line LINE2 of the second group roller and the midpoint O2 are calculated respectively, and the fitting line LINE3 of LINE1 and LINE2, and the midpoint O3 of O1 and O2 are calculated;

[0033] S64, a two-dimensional pitch evaluation coordinate system is established with LINE3 as the X axis, and O3 as the origin of X and Y;

[0034] S65, the tooth pitch evaluation coordinate system is rotated by the process angle a according to the specified requirements on the tenon process drawing, and the left tooth distance LC and the right tooth distance RC are respectively evaluated.

[0035] A turbine blade tenon cross-bar distance evaluation method, applicable to the tenon profile detection method of claim 1, characterized in that it comprises the following steps:

[0036] S71, the actual tenon profile obtained in step S4 is introduced into the tenon analysis software to establish two virtual rolling bar circles, and the diameter of the rolling bar is the theoretical rolling bar diameter required by the technology;

[0037] S72, the virtual rolling bar circles are positioned to the real rolling bar positions in the actual tenon profile;

[0038] S73, the distance between the centers of the two virtual rolling bar circles is measured.

[0039] The present application has the following beneficial effects:

[0040] The present application realizes the spatial scanning and data point collection of the tenon profile by the four-axis coordinate device and the confocal spectral sensor, can detect the tenon profile non-contact, obtain the actual profile of the tenon profile, has higher detection efficiency, and will not cause damage to the tenon surface, realizes high-precision and high-efficiency detection of the tenon profile, makes up for the shortcomings of current tenon measurement, such as manual operation, low precision, and inability to digitize, and can meet the detection requirements of large size and curvature, high precision, and complex evaluation parameters of the turbine blade tenon of the aircraft engine.

[0041] In addition to the purposes, features and advantages described above, the present application has other purposes, features and advantages. The present application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0042] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this application. The embodiments of the present application illustrated in the drawings, and their description, are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0043] Figure 1 It is a process drawing for a certain type of turbine blade tenon.

[0044] Figure 2 It is a flow chart of the non-contact detection method for the tenon profile of the turbine blade of the aircraft engine.

[0045] Figure 3 It is a tenon tolerance band curve diagram.

[0046] Figure 4 It is a tenon theoretical data set diagram.

[0047] Figure 5 For step S3, a schematic diagram of the tenon coordinate system is established.

[0048] Figure 6 For the theoretical profile separation schematic diagram.

[0049] Figure 7 For the tenon pitch evaluation conventional means error schematic diagram.

[0050] Figure 8 For the tenon pitch evaluation conventional means error schematic diagram.

[0051] Figure 9 For the tenon pitch evaluation virtual roller circle establishment schematic diagram.

[0052] Figure 10 For the tenon pitch evaluation evaluation coordinate system establishment schematic diagram.

[0053] Figure 11 For the tenon pitch evaluation evaluation coordinate system establishment schematic diagram. DETAILED DESCRIPTION

[0054] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered by the following.

[0055] Please refer to Figures 1-11 , the present application provides a technical solution: tenon profile detection method, using 4 axis coordinate device and confocal spectral sensor, realize tenon profile scanning collection and non contact optical detection of space point, including the following steps:

[0056] S1, focal length error compensation and indication error compensation of confocal spectral sensor;

[0057] Because the tenon profile machining precision is high, the confocal spectral sensor needs to be compensated for focal length error and indication error;

[0058] S2, convert the theoretical data of tenon profile into a theoretical data set of tenon profile;

[0059] As Figure 3 shown, the theoretical data of tenon profile includes theoretical profile and tolerance band curve;

[0060] As Figure 4 shown, the theoretical data set contains the theoretical value of the point on the theoretical profile, the upper tolerance and the lower tolerance data;

[0061] S3, reference to the aviation blade tenon coordinate system establishment specification, establish the coordinate system of tenon, which is the basis for three-dimensional space positioning of confocal spectral detection;

[0062] S4, after the adjustment of the confocal spectral sensor optical parameter, the tenon topography profile non-contact optical scanning is performed to obtain the actual topography profile of the tenon top;

[0063] According to the size and position of the tenon top, curvature shape, appropriate scanning speed, acceleration and point density, probe angle, turntable angle, optical following, optical frequency, light intensity, filtering and other parameters are confirmed to ensure the efficiency and accuracy of measurement.

[0064] Through the above method, the tenon topography profile can be non-contact detected to obtain the actual profile of the tenon topography profile, the detection efficiency is higher, and the tenon surface is not damaged, the high-precision and high-efficiency detection of the tenon topography profile is realized, the current tenon measurement adopts manual operation, the precision is not high, and the digitalization cannot be realized, and the detection requirements of large size, high precision and complex evaluation parameters of the tenon of the aero-engine blade can be met.

[0065] Specifically, as shown in the figure, in step S1, the focal length error compensation needs to use a matte white ceramic ball as a standard device to ensure the light reflection quality, scan the spiral line in the spherical cap ± 30° area, a total of 5 layers, use the point density 0.1mm / each point, the scanning speed is 10mm / second, the scanning point set uses the fixed ball diameter algorithm to fit and iteratively calculate the ball center coordinates to calibrate the focal length error of the sensor, and the sensor range-80%, 0%, +80% three positions are used to continuously measure three times, the average of the three measurement steps is calculated, and the calibration and compensation of the sensor are completed.

[0066] Specifically, as shown in the figure, in step S1, the confocal spectral sensor indication error compensation method is to use a step gauge or a standard device flat crystal and a gauge block combination to build a standard step difference model, use the confocal spectral sensor to detect the standard step height, evaluate the sensor measurement error, the standard device reference system uses the step gauge or the flat crystal reference surface to establish the first reference of the coordinate system, establishes the Z axis, and measures 4 points; the step gauge or the flat crystal side surface establishes the second reference of the coordinate system, establishes the X axis, and measures 2 to 3 points; the step gauge or the flat crystal third plane establishes the X origin; the distance from the surface of the step cabinet or the gauge block to the reference system Z plane is measured, and the error compensation measurement value is obtained by comparing with the true value agreed by the standard device.

[0067] Specifically, in step S2, since the tenon topography profile tolerance band is a variable tolerance curve, it is very difficult to manually draw and define, and it is easy to cause the problem of excessive area not smooth, leading to curve error, in order to improve the accuracy and efficiency, the drawing software can be used to draw the theoretical profile and the tolerance band and imported into the tenon analysis software to mirror and design consistent graphics;

[0068] Specifically, in step S2, when the theoretical data of the tenon topography profile does not contain the complete tolerance band curve, the complete tolerance band curve needs to be calculated through the continuous transition of the tolerance. The tolerance value of each adjacent two points in the transition region is equal to the ratio of the point distance and the tolerance difference. The specific calculation method is represented as:

[0069]

[0070] In the formula, x1, x2, y1, y2 represent the X and Y coordinates of each adjacent two points, δs represents the distance between the adjacent two points, S represents the total distance of all points in the transition region, LT1, LT2 represent the original tolerance value of the points in the transition region, and LT' represents the calculated transition tolerance value.

[0071] The complete tolerance band curve mentioned here refers to that there is no tolerance band curve in the region except the working surface and the circular arc region. The working surface and the circular arc region have tolerance band curves on the design drawing. The above method is how to calculate the tolerance band of the transition region between the working surface and the circular arc region.

[0072] Specifically, in step S2, as shown in Figure 4 , when the theoretical data of the tenon topography profile contains the complete tolerance band curve, the tolerance value is defined by projecting each point in the theoretical profile to the upper and lower tolerance bands in the vector direction, calculating the intersection points one by one, and calculating the distance. The data is summarized into the X, Y, Z, I, J, K, UT, and LT uniform format tolerance data set;

[0073] Among them, X, Y, and Z represent point coordinates, I, J, and K represent point vectors, UT represents the upper tolerance, and LT represents the lower tolerance.

[0074] Specifically, in step S3, when establishing the coordinate system of the tenon, the aviation blade tenon coordinate system establishment specification is referred to. The physical roller is used to contact the blade working surface, and the coordinate system is established after the contact points of the roller are obtained. This method has been applied to bearing raceway and gear span calculation, as shown in Figure 5 . However, in order to improve the detection efficiency, a contact probe with a diameter equal to the diameter of the roller is used. The specific method of establishing the coordinate system of the tenon is as follows:

[0075] S31, respectively in the front edge direction and the rear edge direction of the tenon, the center position of the measuring needle on the tenon is found through three-dimensional simulation centering sensing. The roller contact point coordinates are calculated through trigonometric function relationship. As shown in the figure, there are a total of 4 points, which are respectively represented as L1, L2, R1, and R2. The tenon tail edge surface measurement point X1 is the reference point specified on the tenon process drawing;

[0076] S32, calculate the axis of the plane using the four contact points of the tenon L1, L2, R1, R2, the orientation is the blade set stacking axis, the direction is pointing to the blade tip, and the Z-axis origin is established;

[0077] S33, calculate the axis using the line connecting L1 and L2 and the line connecting R1 and R2, the direction is towards the blade trailing edge, and the Y-axis origin is established;

[0078] S34, establish the X origin using the X1 point.

[0079] The purpose of tenon coordinate establishment is to ensure that when the tenon profile is detected using a non-contact method, the non-contact sensor carried by the detection device needs to accurately reach the position of the tenon scanning section.

[0080] Specifically, after high-precision forming grinding of the blade tenon, the surface presents a high-brightness state, and the confocal spectral sensor has the ability to detect high-brightness surfaces, but also needs to finely adjust the optical parameters to achieve it. Before starting the scanning task, when the white light focus is focused on the surface of the part, the exposure time is automatically adjusted so that the monitoring light intensity signal is between 15% and 40%, achieving the best;

[0081] Further, as shown in step S4, Figure 6 When the tenon profile is scanned by a non-contact optical method, the tenon profile is symmetrically divided into two parts in the width direction of the tenon to facilitate scanning by a 4-axis coordinate (XYZR) device.

[0082] At present, when evaluating the tenon profile of a turbine blade, a standard enlarged drawing is mainly used, a large vertical projector is used for qualitative detection of profile comparison, and a polyester film or other material is used to enlarge and print the tenon profile and the tolerance band by 25 to 50 times. By manually projecting and comparing the tenon profile and the enlarged drawing under the same light source system, this method has the problems of long manual debugging period, large printing error of the enlarged drawing, low detection efficiency, poor repeatability, inability to obtain detection values such as profile, displacement, pitch, and inability to digitize;

[0083] Therefore, an evaluation method for the tenon profile of a turbine blade of an aero-engine is proposed, which is suitable for the above-mentioned non-contact detection method of the tenon profile of the turbine blade of the aero-engine. The actual profile of the tenon profile is imported into a tenon profile analysis software for profile analysis, including the following steps:

[0084] S51, divide the actual profile of the tenon profile into an overall profile and a working surface profile;

[0085] S52, use the Gaussian least squares method to calculate the deviation and fitting of the overall profile obtained in step S51 to obtain the best fitting curve of the overall profile;

[0086] S53, using the working surface profile obtained in step S51, the deviation and fitting process are calculated again using the quadratic Gaussian least squares method based on the overall best fitting curve to obtain the working surface best fitting curve, and the working surface best fitting curve is compared with the tolerance band curve and the theoretical profile to evaluate the tenon profile;

[0087] The general expression is as follows:

[0088]

[0089] In the formula:

[0090] θ is the optimal fitting parameter

[0091] S is the sum of squares of residuals

[0092] x i ,y i is a data point

[0093] The method uses the working surface as the tenon profile weight set to perform tolerance band best fitting on the entire tenon actual profile in the weight mode to obtain profile analysis data. Since the tenon of the turbine blade of the aero-engine is a typical variable tolerance band profile evaluation, the tolerance of the working surface is usually small, and the tolerance of the circular arc part is usually large. According to the actual assembly needs of the blade tenon on the turbine disc of the aero-engine, the working surface of the tenon is the key part of the entire tenon. In the evaluation process, it is necessary to first ensure that the working surface profile points are within the tolerance band (when the working surface profile is out of tolerance, high-level weight fitting is required to ensure that the most points enter the tolerance band first), and then determine whether the remaining profiles (mainly the circular arc transition part) are within the tolerance band. Finally, the technical requirements of the tenon profile fitting are met.

[0094] The working surface of the tenon of the turbine blade of the aero-engine is very short, and the tolerance requirement is extremely strict, generally in the micron level. There are two methods of conventional method, as shown in Figure 7 , one is to directly evaluate the distance of two working surfaces (lines), when directly calculating the vertical distance, due to the working surface is too short, the small detection error will cause the error to be amplified, as shown in Figure 8 , the method of calculating the projection by referring to the single-span rod distance centering circle center line as the coordinate system reference, since the working surface is single-sided, the centering circle needs to be calculated using the opposite surface, which will cause the two-sided centering circle contact points to be asymmetric;

[0095] Therefore, a method for evaluating the tooth distance of the tenon of the turbine blade of the aero-engine is proposed, which is suitable for the non-contact detection method of the tenon profile of the turbine blade of the aero-engine, comprising the following steps:

[0096] S61, as Figure 9As shown, the actual topography of the tenon obtained in step S4 is imported into the tenon analysis software to establish two sets of virtual roller circles, and the diameter of the virtual roller circle is the theoretical roller diameter required by the technology;

[0097] S62, such as Figure 10 As shown, the virtual roller circle is positioned to the real roller position in the actual topography of the tenon, and the first group of roller lower contact points L1, R1 and the second group of roller upper contact points L2, R2 are obtained;

[0098] The two virtual roller circles of the same group are respectively set on both sides of the actual topography of the tenon. The virtual roller circles contact the two upper and lower adjacent working surfaces at the same time to obtain the real roller position.

[0099] S63, such as Figure 10 As shown, the center line LINE1 and the midpoint O1 of the first group of rollers, the center line LINE2 and the midpoint O2 of the second group of rollers are calculated respectively, and the fitting line LINE3 of LINE1 and LINE2, and the midpoint O3 of O1 and O2 are calculated;

[0100] S64, such as Figure 11 As shown, a two-dimensional pitch evaluation coordinate system is established with LINE3 as the X axis and 03 as the origin of X and Y;

[0101] S65, such as Figure 11 As shown, the tooth pitch evaluation coordinate system is rotated by the process angle α according to the requirements on the tenon process drawing, and the left tooth distance LC and the right tooth distance RC are evaluated respectively.

[0102] like Figure 1 This is the process drawing of a certain type of turbine blade tenon. Figure 1 It can be seen from the figure that the theoretical roller diameter is 2.7 mm and the process angle α is 50°.

[0103] This method uses the centerline fitting method of two groups of virtual roller circles as the baseline method to calculate the tooth pitch. This method fits the positions of the upper and lower groups of virtual roller circles and calculates the tooth pitch in the fitting coordinate system. This method fully considers the problem of inconsistent processing status of different groups of roller positions, and achieves good repeatability of small tooth pitch calculation and good symmetry of calculation results.

[0104] The span is the distance between the centers of the rollers. Traditionally, the measurement method involves manufacturing two very precise physical rollers, manually placing them on the tenon, and then measuring with a micrometer or other measuring tool. This method cannot be digitized and is also affected by manual measurement, resulting in poor repeatability and unreliable measurements.

[0105] Therefore, an aero-engine turbine blade tenon cross-bar distance evaluation method is proposed, which is suitable for the above-mentioned non-contact detection method of aero-engine turbine blade tenon profile, comprising the following steps:

[0106] S71, the actual tenon profile obtained in step S4 is introduced into the tenon analysis software, two virtual rolling bar circles are established, and the diameter of the virtual rolling bar circle is the theoretical rolling bar diameter required by the technical requirement;

[0107] S72, the virtual rolling bar circle is positioned to the real rolling bar position in the actual tenon profile;

[0108] S73, the distance between the centers of the two virtual rolling bar circles is measured.

[0109] The method uses virtual rolling bar circles to replace traditional physical rolling bars, so that the measurement of tenon cross-bar distance is more simple, convenient and accurate.

[0110] When positioning the virtual rolling bar circle to the real rolling bar position, the following four modes can be used:

[0111] 1, point mode: small calculation amount, fast speed, can quickly virtually the lowest circle tangent to the curve. This algorithm is sensitive to point density and quality, and has low repeatability. It is suitable for high-density curve data types.

[0112] 2, Cubic spline mode: the calculation amount increases, but the algorithm is simple and easy to program, the curve is decomposed into each line segment to calculate the tangent circle. To a certain extent, it avoids the curve data type with high point density, and can achieve a certain accuracy.

[0113] 3, linear spline mode: generate B-spline curve for curve points, calculate the lowest circle by tangent to the curve and circle, which has high repeatability and accuracy, and is suitable for uniform point density curve.

[0114] 4, Akima spline mode: a curve interpolation method, which considers the slope and curvature of the curve, and is better than cubic algorithm under the condition of non-uniform point density. In the invention, considering that the optical scanning data shows non-uniform point density, the use of akima algorithm has advantages.

[0115] Because different confocal spectral sensors have different capabilities, the point density of the actual tenon profile measured by them is different, and the above four different calculation methods can be selected according to the actual situation.

[0116] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A tenon profile detection method, using a 4-axis coordinate device and a confocal spectral sensor, realizes the tenon profile scanning collection and the non-contact optical detection of the space point, characterized in that, It comprises the following steps: S1, confocal spectral sensor focal length error compensation and indication error compensation; S2, converting the theoretical data of the tenon profile into a theoretical data set of the tenon profile; The theoretical data of the tenon profile includes a theoretical profile and a tolerance band curve; The theoretical data set includes the theoretical value of the point on the theoretical profile, the upper tolerance and the lower tolerance data; S3, establishing the coordinate system of the tenon according to the specification of the coordinate system of the aerofoil blade tenon; S4, after adjusting the optical parameters of the confocal spectral sensor, performing non-contact optical scanning of the tenon profile to obtain the actual profile of the tenon.

2. The method of mortise profile detection according to claim 1, characterized in that: In step S2, when the theoretical data of the tenon profile does not contain the complete tolerance band curve, the complete tolerance band curve is calculated by transition calculation of the continuous change of the tolerance, and the specific calculation method is represented as: In the formula: x1, x2, y1, y2 represent the X and Y coordinates of each adjacent two points, δs represents the distance between the adjacent two points, S represents the total distance of all points in the transition area, LT1, LT2 represent the original tolerance value of the points in the transition area, and LT' represents the calculated transition tolerance value.

3. The method of claim 1, wherein: In step S2, by projecting each point in the theoretical profile to the upper and lower tolerance bands in the vector direction, the intersection points are calculated one by one, and the distance is defined as the tolerance value, and the data is collected into the X, Y, Z, I, J, K, UT, LT unified format of the theoretical data set with tolerance; Wherein, X, Y, Z represent the point coordinates, I, J, K represent the vector of the point, UT represents the upper tolerance, and LT represents the lower tolerance.

4. The method of claim 1, wherein: In step S3, when establishing the coordinate system of the tenon, a contact probe with a diameter equal to the diameter of the roller is used, and the specific method for establishing the coordinate system of the tenon is as follows: S31, respectively in the front edge direction and the trailing edge direction of the tenon, find the center position of the measuring needle on the tenon by three-dimensional simulation centering sensing, calculate the contact point coordinates of the roller by trigonometric function, a total of 4 points, respectively represented as L1, L2, R1, R2, and X1 is the measurement point of the tenon tail edge surface; S32, using the four contact points L1, L2, R1, R2 of the tenon to calculate the axis of the plane, the azimuth is the blade stacking axis, the direction is towards the blade tip, and the Z axis origin is established; S33, using the connecting line of L1 and L2 and the connecting line of R1 and R2 to calculate the bisector to establish the axis, the direction is towards the blade trailing edge, and the Y axis origin is established; S34, using the X1 point to establish the X origin.

5. The method of claim 1, wherein: In step S4, when non-contact optical scanning of the tenon profile is performed, the tenon profile is symmetrically divided into two parts in the width direction of the tenon.

6. A turbine bucket tip profile evaluation method for turbine bucket tip profile detection method of claim 1, wherein, It comprises the following steps: S51, dividing the actual profile and the theoretical profile of the tenon profile into two parts of the whole profile and the working surface profile; S52, using the whole profile obtained in step S51 to calculate the deviation and fitting by using the Gauss least square method to obtain the whole best fitting curve; S53, on the basis of the whole best fitting curve, using the working surface profile obtained in step S51 to calculate the deviation and fitting by using the quadratic Gauss least square method again to obtain the working surface best fitting curve, comparing the working surface best fitting curve with the tolerance band curve and the theoretical profile to evaluate the tenon profile degree.

7. A turbine blade tenon pitch evaluation method for turbine blade tenon profile detection method of claim 1, characterized in that, It comprises the following steps: S61, the tenon actual profile obtained in step S4 is introduced into the tenon analysis software to establish two groups of virtual roller circles, and the diameter of the roller is the theoretical roller diameter required by the technology; S62, the virtual roller circles are positioned to the real roller positions in the tenon actual profile to obtain the first group of roller lower contact points L1 and R1 and the second group of roller upper contact points L2 and R2; S63, the center line LINE1 and the midpoint O1 of the first group of rollers and the center line LINE2 and the midpoint O2 of the second group of rollers are respectively calculated, and the fitting line LINE3 of LINE1 and LINE2 and the midpoint O3 of O1 and O2 are calculated; S64, a two-dimensional pitch evaluation coordinate system is established with LINE3 as the X axis and O3 as the origin of X and Y; S65, the pitch evaluation coordinate system is respectively rotated by the process angle α according to the specified requirements on the tenon process drawing to respectively evaluate the left tooth distance LC and the right tooth distance RC.

8. A turbine bucket cross pitch evaluation method for turbine buckets of aeroengine, adapted to the method of claim 1, characterized in that, The method comprises the following steps: S71, the tenon actual profile obtained in step S4 is introduced into the tenon analysis software to establish two groups of virtual roller circles, and the diameter of the roller is the theoretical roller diameter required by the technology; S72, the virtual roller circles are positioned to the real roller positions in the tenon actual profile; S73, the distance between the centers of the two virtual roller circles is measured.

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