An automatic measuring method of a twisted and deformed blade

Abstract

This invention relates to the field of blade measurement technology and discloses an automatic measurement method for tortuous and deformed blades. It aims to solve the problems of high labor costs, large measurement errors, low measurement efficiency, and scratch generation in existing methods. The solution mainly includes: positioning and clamping the blade to be measured on a corresponding fixture; obtaining the theoretical coordinate values ​​of multiple theoretical measurement points along the vector direction of the blade; establishing a coordinate system based on a six-point iteration method; using a coordinate measuring machine to detect multiple measurement points on various cross-sections of the blade; for each cross-section, performing optimal fitting calculations based on the corresponding measured points and theoretical profiles; and, in the coordinate system after optimal fitting for each cross-section, detecting the blade according to the actual measurement points corresponding to each theoretical measurement point to obtain measured coordinate values, and determining the dimensions of the blade based on the measured coordinate values. This invention achieves rapid, scratch-free automatic measurement, reduces labor costs, and improves the reliability of dimensional measurement, making it particularly suitable for aero-engine blades.

Description

Technical Field

[0001] This invention relates to the field of blade measurement technology, and specifically to an automatic measurement method for twisted and deformed blades. Background Technology

[0002] After polishing and repairing aero-engine fan blades or turbine blades, it is necessary to measure the wall thickness and chord length of the weakest points of the blades to ensure the strength of the blades.

[0003] Current methods for dimensional inspection of repaired aero-engine blades have at least the following shortcomings:

[0004] (1) After polishing and repair, the wall thickness and chord length of domestic aero-engine blades are mainly measured by manual inspection methods such as special wall thickness gauges, calipers, and gauges, which have problems such as high labor costs and large measurement errors.

[0005] (2) The wall thickness and chord length of the blades after repair are smaller than those in the drawings, and the consistency of each blade is poor. In addition, the blade profile has problems such as torsion and wear of tenon positioning reference after service. Using the traditional blade profile scanning mode, especially for fan blades with leading and trailing edge R radii less than 0.3mm, the automatic scanning is extremely unstable and it is difficult to achieve automatic measurement of blades with complex torsional surface deformation.

[0006] (3) Fan rotor blades with bosses have incomplete blade profile sections in the section where the boss is located, the blade root or the blade tip virtual section, which are dead zones for tooling or traditional coordinate scanning measurement.

[0007] (4) Whether it is the traditional manual tooling measurement mode or the three-coordinate scanning measurement mode, measurement scratches will be formed on the surface of the blade, which will increase the difficulty of processing the blade after measurement and also pose a quality risk. Summary of the Invention

[0008] The present invention aims to propose an automatic measurement method for twisted and deformed blades, so as to realize rapid and traceless automatic measurement of the dimensions of complex twisted and deformed blades, reduce labor costs and improve the reliability of dimensional measurement.

[0009] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0010] An automatic measurement method for twisted and deformed blades, the method comprising:

[0011] Step 1: Place the blade to be tested on the corresponding fixture for positioning and clamping;

[0012] Step 2: Obtain the CAD model of the blade to be tested, and obtain the theoretical coordinate values ​​of multiple theoretical measurement points with vector directions on the blade to be tested based on the CAD model;

[0013] Step 3: Use a coordinate measuring machine or comparator to detect at least six measuring points on the blade to be tested, and establish a coordinate system based on the six-point iteration method;

[0014] Step 4: Use a coordinate measuring machine or a comparator to detect multiple measuring points on each section of the blade to be tested, obtain the actual measuring points of each section, and perform the best fitting calculation for each section based on the corresponding actual measuring points and theoretical profile to obtain the coordinate system after the best fitting of each section.

[0015] Step 5: Under the coordinate system after the best fit of each section, determine the position of the actual measuring point corresponding to each theoretical measuring point, detect the blade to be tested according to the position of the actual measuring point, obtain the measured coordinate value of each actual measuring point, and determine the size of the blade to be tested according to the measured coordinate value.

[0016] Furthermore, in step 2, the multiple theoretical measurement points of the blade under test with the vector direction include: the first and second measurement points corresponding to the leading edge wall thickness, the third and fourth measurement points corresponding to the maximum wall thickness, the fifth and sixth measurement points corresponding to the trailing edge wall thickness, and the seventh and eighth measurement points corresponding to the chord length.

[0017] Furthermore, in step 3, the at least six measuring points of the blade to be tested are thirteen, including: three measuring points on the blade base, three measuring points on the blade back, three measuring points on the air intake side, three measuring points on the air exhaust side, and one measuring point on the blade tip.

[0018] Furthermore, in step 4, the number of measuring points on each cross section of the blade to be tested is six, including: two measuring points on the blade base, two measuring points on the blade back, one measuring point on the air intake side, and one measuring point on the air exhaust side.

[0019] Furthermore, in step 5, determining the location of the actual measuring point corresponding to each theoretical measuring point specifically includes:

[0020] For the third, fourth, seventh, and eighth measurement points, the positions of the corresponding actual measurement points are determined in the best-fit measured profile based on the vector direction;

[0021] For the first, second, fifth, and sixth measuring points, the positions of the corresponding actual measuring points are determined in the best-fit measured profile based on their distance from the seventh measuring point and the offset of the seventh measuring point in the chord direction. Alternatively, the positions of the corresponding actual measuring points are determined in the best-fit measured profile based on their distance from the eighth measuring point and the offset of the eighth measuring point in the chord direction.

[0022] Further, in step 5, determining the size of the blade to be measured based on the measured coordinate values ​​specifically includes:

[0023] Based on the measured coordinate values ​​of the actual measuring points corresponding to the first and second measuring points in the measured profile after best fitting, calculate the first distance between the actual measuring points corresponding to the first and second measuring points. The first distance is the actual leading edge wall thickness of the blade to be tested.

[0024] Based on the measured coordinates of the actual measuring points corresponding to the third and fourth measuring points in the best-fit measured profile, the second distance between the actual measuring points corresponding to the third and fourth measuring points is calculated. The second distance is the actual maximum wall thickness of the blade to be tested.

[0025] Based on the measured coordinates of the actual measuring points corresponding to the fifth and sixth measuring points in the best-fit measured profile, the third distance between the actual measuring points corresponding to the fifth and sixth measuring points is calculated. The third distance is the actual trailing edge wall thickness of the blade to be measured.

[0026] Based on the measured coordinates of the actual measuring points corresponding to the seventh and eighth measuring points in the best-fit measured profile, the fourth distance between the actual measuring points corresponding to the seventh and eighth measuring points is calculated, and the fourth distance is the actual chord length of the blade to be measured.

[0027] Furthermore, the method also includes:

[0028] The standard leading edge wall thickness, standard maximum wall thickness, standard trailing edge wall thickness, and standard chord length of the blade under test are obtained by coordinate measuring machine (CMM). The actual leading edge wall thickness, actual maximum wall thickness, actual trailing edge wall thickness, and actual chord length are then compared with the standard leading edge wall thickness, standard maximum wall thickness, standard trailing edge wall thickness, and standard chord length to determine whether the measurement accuracy meets the requirements. If not, the position of the theoretical measurement point is corrected until the measurement accuracy meets the requirements.

[0029] Furthermore, the method also includes generating a corresponding measurement report based on the batch number, serial number, and measurement data of the blade to be tested.

[0030] Furthermore, the method also includes:

[0031] Extract the measurement data from the measurement report, determine whether the blade under test is qualified based on the measurement data, and upload the measurement report and the judgment result to the enterprise data management system.

[0032] Furthermore, the coordinate measuring machine is either a contact coordinate measuring machine or a non-contact coordinate measuring machine.

[0033] The beneficial effects of this invention are as follows: The automatic measurement method for tortuous and deformed blades provided by this invention can realize the automatic measurement of blade dimensions by compiling a corresponding automatic blade measurement program in the blade analysis software. Compared with traditional manual tooling measurement, automatic measurement reduces accuracy and repeatability errors, and can measure the wall thickness at any touchable position on the blade body, meeting the special measurement needs of the fan rotor blade repair process, filling the dead zone area of ​​traditional scanning measurement, and overcoming the problems of measurement scratches, low efficiency, and unstable continuous automatic measurement in manual measurement mode and traditional three-coordinate scanning measurement mode. It realizes traceless and rapid measurement, reduces the difficulty of blade processing after measurement, and ensures safety. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating the automatic measurement method for twisted and deformed blades according to an embodiment of the present invention.

[0035] Figure 2 This is a schematic diagram of the clamping structure of the blade to be tested according to an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of the position structure of the theoretical measuring point of the blade under test according to an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram illustrating the optimal fitting effect described in an embodiment of the present invention;

[0038] Figure 5 This is a schematic diagram illustrating the coordinate transformation principle described in an embodiment of the present invention;

[0039] Explanation of reference numerals in the attached figures:

[0040] A - First measuring point; B - Second measuring point; C - Third measuring point; D - Fourth measuring point; E - Fifth measuring point; F - Sixth measuring point; G - Seventh measuring point; H - Eighth measuring point. Detailed Implementation

[0041] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0042] This invention aims to provide an automatic measurement method for tortuous and deformed blades, enabling rapid and traceless automatic measurement of blades. The main technical solution includes: positioning and clamping the blade to be measured on a corresponding fixture; acquiring a CAD model of the blade to be measured, and obtaining the theoretical coordinate values ​​of multiple theoretical measurement points with vector directions on the blade based on the CAD model; using a coordinate measuring machine (CMM) to detect at least six measurement points on the blade to be measured, and establishing a coordinate system based on a six-point iteration method; using the CMM to detect multiple measurement points on various cross-sections of the blade to be measured, obtaining the actual measurement points of each cross-section; for each cross-section, performing best-fit calculations based on the corresponding actual measurement points and theoretical profiles to obtain the best-fit coordinate system for each cross-section; determining the position of the actual measurement point corresponding to each theoretical measurement point in the best-fit coordinate system for each cross-section; detecting the blade to be measured based on the position of the actual measurement point to obtain the measured coordinate values ​​of each actual measurement point; and determining the size of the blade to be measured based on the measured coordinate values.

[0043] Specifically, the present invention first places the blade to be tested on a special fixture for positioning and clamping. The special fixture has automatic clamping and releasing functions and can be integrated with an automatic line. The special fixture can reduce the measurement accuracy error and repeated clamping and positioning error of the blade. Then, an automatic measurement program is developed to automatically measure the dimensions of the blade under test. The process of the automatic measurement program includes: First, obtaining a theoretical model from the CAD model of the blade under test and acquiring the coordinate values ​​of each theoretical measuring point in the theoretical model. The dimensions calculated using the coordinate values ​​of the theoretical measuring points are consistent with the theoretical dimensions of the blade under test. Next, a coordinate measuring machine (CMM) is used to detect multiple measuring points on the blade under test and a coordinate system is established based on the six-point iteration principle to make the actual overall contour of the blade under test more closely match the theoretical model, facilitating the next step of optimal fitting calculation. Then, the CMM detects multiple feature points corresponding to the measured contour of each section of the blade under test, and performs optimal fitting between the feature points and the theoretical section, fitting the measured contour of the blade under test to the middle region of the theoretical contour. Finally, based on the measured contour in the optimally fitted coordinate system, the positions of the actual measuring points corresponding to the theoretical measuring points in the measured contour are determined, and the measured coordinate values ​​of each actual measuring point are obtained by detecting the blade under test based on the positions of the actual measuring points. The actual dimensions of the blade under test can then be calculated based on these measured coordinate values. By executing the above automatic measurement program in the blade analysis software, the size of the blade to be measured can be automatically measured.

[0044] Example

[0045] Please see Figure 1 The automatic measurement method for tortuous and deformed blades according to embodiments of the present invention includes the following steps:

[0046] Step 1: Place the blade to be tested on the corresponding fixture for positioning and clamping;

[0047] This embodiment uses a specialized fixture capable of precisely positioning and clamping the blades, featuring automatic clamping and releasing functions, and can be integrated with an automated production line. This fixture can control the blade re-clamping and positioning error to within 0.2mm.

[0048] For example, if the blade to be tested is a fan rotor blade of a certain type of aero-engine, a dovetail tenon fan rotor blade rapid self-positioning automatic fixture can be used. For the clamping and positioning principle of the blade to be tested, please refer to [link to relevant documentation]. Figure 2 The blade is positioned using its inclined surface and end face 1, with end face 2 providing auxiliary clamping, and the bottom surface automatically clamping and releasing. This self-positioning method reduces the repeatability error of the blade to be measured to within 0.2mm, which helps improve the stability of automatic blade measurement.

[0049] After the blade to be tested is positioned and clamped in a special fixture, it is automatically measured using a coordinate measuring machine (CMM) or a comparator. The CMM can be either a contact CMM or a non-contact CMM; this embodiment does not impose any limitation on either. The automatic measurement procedure includes the following steps:

[0050] Step 2: Obtain the CAD model of the blade to be tested, and obtain the theoretical coordinate values ​​of multiple theoretical measurement points with vector directions on the blade to be tested based on the CAD model;

[0051] This embodiment obtains the theoretical coordinate values ​​of each theoretical measuring point with vector direction in the theoretical coordinate system of the blade based on the wall thickness and chord length positions of each section of the blade under test. Specifically, the IGES format CAD model of the blade under test can be imported into the MODUS blade analysis software to obtain the theoretical coordinate values ​​of each theoretical measuring point with vector direction.

[0052] Please see Figure 3 In this embodiment, the multiple theoretical measurement points of the blade under test include: the first measurement point A and the second measurement point B corresponding to the leading edge wall thickness, the third measurement point C and the fourth measurement point D corresponding to the maximum wall thickness, the fifth measurement point E and the sixth measurement point F corresponding to the trailing edge wall thickness, and the seventh measurement point G and the eighth measurement point H corresponding to the chord length. The theoretical values ​​corresponding to the leading edge wall thickness, maximum wall thickness, trailing edge wall thickness, and chord length calculated from the theoretical coordinate values ​​of each theoretical measurement point are consistent, that is, the dimensions of a brand-new standard blade.

[0053] Step 3: Use a coordinate measuring machine or comparator to detect at least six measuring points on the blade to be tested, and establish a coordinate system based on the six-point iteration method;

[0054] In this embodiment, a contact probe of a coordinate measuring machine can be used to measure three measuring points on the blade base, three measuring points on the blade back, three measuring points on the inlet edge, three measuring points on the exhaust edge, and one measuring point on the blade tip, for a total of thirteen measuring points. Then, a coordinate system is established using the six-point iteration principle, and the overall profile position of the blade is made to better match the theoretical model through blade iteration, which facilitates the next step of optimal fitting calculation.

[0055] Step 4: Use a coordinate measuring machine or a comparator to detect multiple measuring points on each section of the blade to be tested, obtain the actual measuring points of each section, and perform the best fitting calculation for each section based on the corresponding actual measuring points and theoretical profile to obtain the coordinate system after the best fitting of each section.

[0056] This embodiment uses a coordinate measuring machine (CMM) contact probe to measure six points on the same cross-section of the blade, including two points on the blade head, two points on the blade back, one point on the inlet edge, and one point on the exhaust edge. Feature points of each cross-section of the blade are acquired, and the feature points of each cross-section are optimally fitted to the theoretical cross-section. The profile of the blade cross-section is fitted to the middle region of the theoretical profile. For the changes in the measured profile and the theoretical profile before and after optimal fitting, please refer to [reference needed]. Figure 4 Follow this method to sequentially complete the best fit for each cross-section of the blade under test.

[0057] Step 5: Under the coordinate system after the best fit of each section, determine the position of the actual measuring point corresponding to each theoretical measuring point, detect the blade to be tested according to the position of the actual measuring point, obtain the measured coordinate value of each actual measuring point, and determine the size of the blade to be tested according to the measured coordinate value.

[0058] In this embodiment, for the third measuring point C, the fourth measuring point D, the seventh measuring point G, and the eighth measuring point H, the positions of the corresponding actual measuring points are determined in the best-fit measured contours based on the vector directions.

[0059] Specifically, after performing the best fit on the measured profile, the vector direction of each theoretical measuring point is obtained. Based on the corresponding vector direction, the positions of the actual measuring points corresponding to the third measuring point C, the fourth measuring point D, the seventh measuring point G, and the eighth measuring point H in the measured profile are determined. That is, in the measured profile, the positions of the actual measuring point C' corresponding to the third measuring point C, the actual measuring point D' corresponding to the fourth measuring point D, the actual measuring point G' corresponding to the seventh measuring point G, and the actual measuring point H' corresponding to the eighth measuring point H are determined respectively. Based on the positions of the actual measuring points, touch measurement is performed, and then the measured coordinate values ​​of the actual measuring points C', D', G', and H' are obtained respectively.

[0060] For the first measuring point A, the second measuring point B, the fifth measuring point E, and the sixth measuring point F, the position of the corresponding actual measuring point is determined in the best-fit measured profile based on the distance between them and the seventh measuring point G and the offset of the seventh measuring point G in the chord direction, or the position of the corresponding actual measuring point is determined in the best-fit measured profile based on the distance between them and the eighth measuring point H and the offset of the eighth measuring point H in the chord direction.

[0061] To further improve measurement accuracy, this embodiment determines the positions of the corresponding actual measurement points in the best-fit measured profile for the first measurement point A and the second measurement point B based on their distances to the seventh measurement point G and the offset of the seventh measurement point G in the chord direction. Similarly, for the fifth and sixth measurement points, the positions are determined in the best-fit measured profile based on their distances to the eighth measurement point H and the offset of the eighth measurement point H in the chord direction.

[0062] Specifically, for the first measuring point A and the second measuring point B, this embodiment first determines their distance from the seventh measuring point G, and after performing the best fit on the measured profile, determines the offset of the seventh measuring point G in the chord direction. Then, based on this distance and offset, the position of the corresponding actual measuring point is determined in the best-fitted measured profile. That is, in the measured profile, the positions of the actual measuring point A' corresponding to the first measuring point A and the actual measuring point B' corresponding to the second measuring point B are determined respectively, and touch measurement is performed based on the positions of the actual measuring points to obtain the measured coordinate values ​​of the actual measuring points A' and B' respectively.

[0063] For the fifth measuring point E and the sixth measuring point F, this embodiment first determines their distance from the eighth measuring point H. After performing the best fit on the measured profile, the offset of the eighth measuring point H in the chord direction is determined. Then, based on the distance and offset, the position of the corresponding actual measuring point is determined in the best-fitted measured profile. That is, in the measured profile, the positions of the actual measuring point E' corresponding to the fifth measuring point E and the actual measuring point F' corresponding to the sixth measuring point F are determined respectively, and the measured coordinate values ​​of the actual measuring points E' and F' are obtained respectively.

[0064] It is understandable that after optimal fitting, the theoretical measurement points in the theoretical profile will deviate somewhat from the actual measurement points in the measured profile. Please refer to [link / reference]. Figure 5 Taking the fifth measuring point E as an example, let the coordinates of the fifth measuring point E be (X, Y, Z; I, J, K). Then the coordinate transformation formula from the fifth measuring point E to the actual measuring point E' is: E' = (X + rsinθ, Y + rcosθ, Z; I, J, K), where r is the offset of the eighth measuring point H, and θ is the vector direction of the fifth measuring point E.

[0065] In particular, in practical applications, the best fit of all cross sections of the blade under test can be completed, and then each cross section of the blade under test can be touched in turn to obtain the required measured coordinate values; or after completing the best fit of a cross section, the current cross section can be touched immediately to obtain the required measured coordinate values ​​of the measuring point, and the best fit and touching work of the remaining cross sections can be completed in turn.

[0066] After obtaining the measured coordinate values ​​of each actual measuring point, the actual leading edge wall thickness, actual maximum wall thickness, actual trailing edge wall thickness, and actual chord length of the blade under test can be calculated based on the measured coordinate values.

[0067] Specifically, based on the measured coordinate values ​​of the actual measuring points corresponding to the first measuring point A and the second measuring point B in the best-fit measured profile, the first distance between the actual measuring point A' corresponding to the first measuring point A and the actual measuring point B' corresponding to the second measuring point B is calculated. The first distance is the actual leading edge wall thickness of the blade to be measured.

[0068] Based on the measured coordinates of the actual measuring points corresponding to the third measuring point C and the fourth measuring point D in the measured profile after the best fit, calculate the second distance between the actual measuring point C' corresponding to the third measuring point C and the actual measuring point D' corresponding to the fourth measuring point D. The second distance is the actual maximum wall thickness of the blade to be measured.

[0069] Based on the measured coordinates of the actual measuring points corresponding to the fifth measuring point E and the sixth measuring point F in the measured profile after the best fit, calculate the third distance between the actual measuring point E' corresponding to the fifth measuring point E and the actual measuring point F' corresponding to the sixth measuring point F. The third distance is the actual trailing edge wall thickness of the blade to be measured.

[0070] Based on the measured coordinates of the actual measuring points corresponding to the seventh measuring point G and the eighth measuring point H in the measured profile after best fitting, calculate the fourth distance between the actual measuring point G' corresponding to the seventh measuring point G and the actual measuring point H' corresponding to the eighth measuring point H. The fourth distance is the actual chord length of the blade to be measured.

[0071] After developing the automatic program for the blade under test according to the above process, the actual leading edge wall thickness, maximum wall thickness, trailing edge wall thickness, and chord length of the blade under test can be automatically measured. Statistical analysis was conducted to compare the differences in wall thickness and chord length values ​​obtained by the above measurement method and coordinate measuring machine (CMM) scanning. Data comparison showed that the average deviation of the measured blade wall thickness, chord length, and CMM results in this embodiment was ≤0.02mm, and the repeatability error was ≤0.01mm. Compared to the original manual measurement with an accuracy error of approximately ±0.04mm and a repeatability error of approximately ±0.02mm, there has been a significant improvement. The measurement results meet the accuracy requirements for checking the wall thickness and chord length dimensions of the fan rotor after repair.

[0072] After automatically loading and unloading all batches of engine blades, the aforementioned automatic measurement method can be used to complete the automatic measurement of the blades. In this embodiment, a loading and unloading rack is used to store batches of fan rotor blades, and a robot is used to move the blades between the loading and unloading rack, the self-positioning fixture, and the triaxial measuring machine, enabling unattended operation of the measurement process.

[0073] To further improve the accuracy of blade measurement, this embodiment can also obtain the standard leading edge wall thickness, standard maximum wall thickness, standard trailing edge wall thickness, and standard chord length of the blade under test through coordinate scanning. The measured actual leading edge wall thickness, actual maximum wall thickness, actual trailing edge wall thickness, and actual chord length are compared with the standard leading edge wall thickness, standard maximum wall thickness, standard trailing edge wall thickness, and standard chord length to determine whether the measurement accuracy meets the requirements. If not, the position of the theoretical measurement point is corrected until the measurement accuracy meets the requirements.

[0074] To facilitate user management and analysis of measurement data, this embodiment can also generate corresponding measurement reports based on the batch number, serial number, and measurement data of the blade under test. For example, the blade measurement software can output the wall thickness and chord length data of each cross-section of a single blade, and output Word or Excel files according to the blade batch number and serial number. Dedicated data processing software can also be used to extract the measurement data from the measurement report, determine whether the blade under test is qualified based on the measurement data, and upload the measurement report and the determination results to the enterprise data management system.

[0075] In summary, the automatic measurement method for tortuous and deformed blades provided in this embodiment achieves automatic measurement of blade dimensions by developing a corresponding automatic blade measurement program in the blade analysis software. Compared with traditional manual tooling measurement, automatic measurement reduces accuracy and repeatability errors, and can measure the wall thickness at any touchable position on the blade body, meeting the special measurement needs of the fan rotor blade repair process. It fills the dead zone area of ​​traditional scanning measurement, and overcomes the problems of measurement scratches, low efficiency, and unstable continuous automatic measurement in manual measurement mode and traditional three-coordinate scanning measurement mode. It achieves traceless and rapid measurement, reduces the difficulty of blade processing after measurement, and ensures safety.

Claims

1. An automatic measurement method for twisted and deformed blades, characterized in that, The method includes: Step 1: Place the blade to be tested on the corresponding fixture for positioning and clamping; Step 2: Obtain the CAD model of the blade to be tested, and obtain the theoretical coordinate values ​​of multiple theoretical measurement points with vector directions on the blade to be tested based on the CAD model; The theoretical measurement points of the blade under test with vector direction include: the first and second measurement points corresponding to the leading edge wall thickness, the third and fourth measurement points corresponding to the maximum wall thickness, the fifth and sixth measurement points corresponding to the trailing edge wall thickness, and the seventh and eighth measurement points corresponding to the chord length. Step 3: Use a coordinate measuring machine or comparator to detect at least six measuring points on the blade to be tested, and establish a coordinate system based on the six-point iteration method; Step 4: Use a coordinate measuring machine or a comparator to detect multiple measuring points on each section of the blade to be tested, obtain the actual measuring points of each section, and perform the best fitting calculation for each section based on the corresponding actual measuring points and theoretical profile to obtain the coordinate system after the best fitting of each section. Step 5: Under the coordinate system after the best fit of each section, determine the position of the actual measuring point corresponding to each theoretical measuring point, detect the blade to be tested according to the position of the actual measuring point, obtain the measured coordinate value of each actual measuring point, and determine the size of the blade to be tested according to the measured coordinate value. Determining the location of the actual measuring point corresponding to each theoretical measuring point specifically includes: For the third, fourth, seventh, and eighth measurement points, the positions of the corresponding actual measurement points are determined in the best-fit measured profile based on the vector direction; For the first, second, fifth, and sixth measuring points, the positions of the corresponding actual measuring points are determined in the best-fit measured profile based on their distance from the seventh measuring point and the offset of the seventh measuring point in the chord direction. Alternatively, the positions of the corresponding actual measuring points are determined in the best-fit measured profile based on their distance from the eighth measuring point and the offset of the eighth measuring point in the chord direction.

2. The automatic measurement method for twisted and deformed blades as described in claim 1, characterized in that, In step 3, the at least six measuring points of the blade to be tested are thirteen, including: three measuring points on the blade base, three measuring points on the blade back, three measuring points on the air inlet side, three measuring points on the air outlet side, and one measuring point on the blade tip.

3. The automatic measurement method for twisted and deformed blades as described in claim 1, characterized in that, In step 4, there are six measuring points on each cross section of the blade to be tested, including: two measuring points on the blade base, two measuring points on the blade back, one measuring point on the air intake side, and one measuring point on the air exhaust side.

4. The automatic measurement method for twisted and deformed blades as described in claim 1, characterized in that, Step 5 involves determining the dimensions of the blade to be measured based on the measured coordinate values, specifically including: Based on the measured coordinate values ​​of the actual measuring points corresponding to the first and second measuring points in the measured profile after best fitting, calculate the first distance between the actual measuring points corresponding to the first and second measuring points. The first distance is the actual leading edge wall thickness of the blade to be tested. Based on the measured coordinates of the actual measuring points corresponding to the third and fourth measuring points in the best-fit measured profile, the second distance between the actual measuring points corresponding to the third and fourth measuring points is calculated. The second distance is the actual maximum wall thickness of the blade to be tested. Based on the measured coordinates of the actual measuring points corresponding to the fifth and sixth measuring points in the best-fit measured profile, the third distance between the actual measuring points corresponding to the fifth and sixth measuring points is calculated. The third distance is the actual trailing edge wall thickness of the blade to be measured. Based on the measured coordinates of the actual measuring points corresponding to the seventh and eighth measuring points in the best-fit measured profile, the fourth distance between the actual measuring points corresponding to the seventh and eighth measuring points is calculated, and the fourth distance is the actual chord length of the blade to be measured.

5. The automatic measurement method for twisted and deformed blades as described in claim 4, characterized in that, The method further includes: The standard leading edge wall thickness, standard maximum wall thickness, standard trailing edge wall thickness, and standard chord length of the blade under test are obtained by coordinate measuring machine (CMM). The actual leading edge wall thickness, actual maximum wall thickness, actual trailing edge wall thickness, and actual chord length are then compared with the standard leading edge wall thickness, standard maximum wall thickness, standard trailing edge wall thickness, and standard chord length to determine whether the measurement accuracy meets the requirements. If not, the position of the theoretical measurement point is corrected until the measurement accuracy meets the requirements.

6. The automatic measurement method for twisted and deformed blades as described in claim 4, characterized in that, The method further includes generating a corresponding measurement report based on the batch number, serial number, and measurement data of the blade to be tested.

7. The automatic measurement method for twisted and deformed blades as described in claim 6, characterized in that, The method further includes: Extract the measurement data from the measurement report, determine whether the blade under test is qualified based on the measurement data, and upload the measurement report and the judgment result to the enterprise data management system.

8. The automatic measurement method for tortuous and deformed blades as described in any one of claims 1 to 7, characterized in that, The coordinate measuring machine is either a contact coordinate measuring machine or a non-contact coordinate measuring machine.

Images