A blade positioning detection system and method for an aeroengine

Abstract

The present application relates to the technical field of aero-engine detection, in particular to a blade positioning detection system and method for aero-engine, which is characterized by the following: a plurality of line laser sensor groups are used to detect the fan blades of the aero-engine, and an inner rotating mechanism and an outer surrounding mechanism are used to position and detect the fan blades. The inner rotating mechanism can provide necessary self-rotation of the fan blades during detection, and can also correct the center line deviation of the fan blades. The outer surrounding mechanism is used to adjust the positions of the plurality of line laser sensor groups for different batches of fan blades with different degrees of distortion, so as to complementarily cover the fillet area of the fan blades at different angles, thereby avoiding the light path deviation and positioning drift caused by the traditional moving sensor. The architecture of 'fixed sensor + blade rotation' not only retains the spatial complementarity of the plurality of line laser sensors, but also expands the coverage range of the single line laser sensor for the distorted blades through rotation, thereby providing stable geometric conditions for continuous detection of the high-curvature area.

Description

Technical Field

[0001] This invention relates to the field of aero-engine testing technology, specifically to an aero-engine blade positioning and testing system and method. Background Technology

[0002] Blades are one of the key components in aerospace engines, and their surface quality directly determines the engine's service life and performance. In aero-engines, blades can be categorized by their practical application into fan blades, compressor blades, and turbine blades. Fan and compressor blades are cold-end components, while turbine blades are hot-end components. Compressor blades can be further divided into compressor rotor blades and compressor stator blades, while turbine blades can be divided into turbine working blades and turbine guide vanes. The fan blades initially compress the air entering the engine. The compressed gas is then split into two paths: one path enters the inner duct for further compression, while the other path exits at high speed through the outer bypass duct, generating thrust.

[0003] Due to differences in their specific application scenarios and locations, the three types of blades also differ in shape. Compressor blades are small blades in aero-engines, characterized by thin profiles, long spans, low rigidity, and variable curvature. Turbine blades have a structure similar to fan blades, but due to the special nature of their application, their materials differ from fan blades; some are made using single-crystal high-temperature alloys. For fan blades, such as... Figure 1 The blade shown is a medium or large blade in an aero-engine. It is typically characterized by thin blade edges, large blade twist, and offset blade centerline. In actual use, its twist degree, i.e., the torsion angle, is much greater than that of compressor blades. The reduction in the angle of attack from the blade root to the blade tip is typically in the range of 20°-60°. At the same time, in order to ensure the adaptation of vibration stability and circumferential flow field uniformity during use, the blade centerline is offset or deflected. This allows it to reconstruct the angle of attack and flow direction of the airflow entering the blade cascade, thereby reducing the impact of the cutting airflow on the blade leading edge. It can also weaken the horseshoe vortex and channel vortex in the subsequent blade cascade to a certain extent. Therefore, in the design, its offset angle Δ is usually 2°-9°.

[0004] During testing, contact measuring devices can be used, such as a coordinate measuring probe to make contact along the blade edge. Although this contact testing method can conform to the blade shape and perform layer-by-layer testing, thereby reducing the influence of large blade distortion and blade centerline offset, this method is slow in terms of measurement speed. In addition, the rounded corners of the fan blade edge make it difficult to make contact with the probe of the contact testing device, resulting in measurement errors and affecting the test results.

[0005] Non-contact measuring devices can also be used for inspection, typically employing single-sided point or line laser scanning. After obtaining data on the points, lines, and surfaces of the blade, the actual shape of the blade under test is reconstructed. This non-contact method avoids the influence of the measuring probe on the blade's attitude. However, when inspecting, especially for aero-engine fan blades, the overall thickness of the blade profile should not exceed 5mm, with the thickness at the blade edge less than 1mm and rounded corners. Furthermore, the blade edge is a key area for inspection, avoiding obvious non-rounded corner shapes such as square or pointed tips. During inspection, the blade base and blade back of the fan blade, due to their curvature or concavity, do not experience significant reflections that severely affect the inspection results when using laser scanning. However, the blade edge, with its convex rounded corners, presents challenges when using single-sided point or line laser scanning. Figure 2 As shown, with Figure 1 Taking the leaf margin in region A as an example, when point laser or line laser detection is performed on one side, severe scattering will occur, affecting the detection results.

[0006] Meanwhile, Chinese patent CN220498460U discloses a quick-positioning blade clamp that enables the rapid loading and unloading of fan blades, making it applicable to the positioning and testing of aero-engine blades. However, it still needs to be used in conjunction with other structures to correct the offset of the blade centerline during testing. Summary of the Invention

[0007] The purpose of this invention is to provide a blade positioning and detection system and method for aero-engines, addressing the aforementioned problems.

[0008] The technical solution adopted in this invention is as follows: a blade positioning and detection system for aero-engines, comprising a blade positioning mechanism, an inner rotation mechanism, an outer circumferential mechanism, and a detection mechanism;

[0009] The blade positioning mechanism for aero-engines can be used to install aero-engine blades and adjust the angle of the aero-engine blades.

[0010] The internal rotation mechanism is located below the blade positioning mechanism for aero-engines and can drive the blade positioning mechanism for aero-engines to rotate around the central axis.

[0011] The outer surrounding mechanism is located on the outer periphery of the inner rotating mechanism and is used to install the detection mechanism;

[0012] The detection mechanism includes multiple line laser sensor groups and a processor. The multiple line laser sensor groups are arranged around the outer periphery of the aero-engine blade positioning mechanism and can collect image data of the aero-engine blades. The processor is used to process the image data collected by the multiple line laser sensor groups and generate detection results.

[0013] Furthermore, the blade positioning mechanism for aero-engines includes a mounting base, a connecting rod, and a spherical body;

[0014] The aero-engine blades can be mounted on a mounting base, and the vertical projection of the aero-engine blades covers the center of the mounting base.

[0015] One end of the connecting rod is connected to the center of the bottom of the mounting base, and the other end of the connecting rod is connected to the spherical body.

[0016] The spherical object can be placed into the internal rotating mechanism.

[0017] Furthermore, a mounting groove is provided on the top of the mounting base, and the mounting groove passes through the center of the mounting base, with a stop block provided at one side opening of the mounting groove;

[0018] The tenon of the aero-engine blade can be pushed into the mounting groove from one side of the mounting groove by a stop block;

[0019] The abutment is provided with screws and is detachably connected to the mounting base by the screws.

[0020] Furthermore, the internal rotating mechanism includes a rotating seat and a base. A rotary motor is mounted on the base. The rotating seat is installed on the base and connected to the power output shaft of the rotary motor, rotating under the drive of the rotary motor.

[0021] Furthermore, the top of the rotating seat is provided with an opening, and a limiting structure is provided inside the rotating seat. The spherical body can be placed inside the rotating seat and limited by the limiting structure, and the connecting rod can pass through the opening.

[0022] Furthermore, the outer surrounding mechanism includes an annular track and a sliding seat. The annular track is located on the outer periphery of the rotating seat, and the center of the annular track coincides with the center of the rotating seat. The sliding seat is located on the annular track and can move on the annular track. The sliding seat is used to mount the line laser sensor assembly.

[0023] Furthermore, the detection mechanism includes a first line laser sensor group and a second line laser sensor group, both of which are mounted on a sliding seat and face the center of the circular track. The angle between the first line laser sensor group, the second line laser sensor group and the center of the circular track is less than the maximum torsion angle of the blade for aero-engines.

[0024] This application provides a blade positioning and detection system for aero-engines, and also provides a method for positioning and detection of blades for aero-engines, comprising the following steps:

[0025] S1. Installation of the rotating seat: Install the rotating seat on the power output shaft of the rotary motor, place the spherical body inside the rotating seat, insert the connecting rod from the opening, with one end of the connecting rod connected to the spherical body and the other end of the connecting rod connected to the mounting seat;

[0026] S2. Blade positioning and attitude adjustment: Place the aero-engine blade to be tested on the mounting base and ensure that the tenon of the aero-engine blade is in contact with the top surface of the mounting base. Take an image of the aero-engine blade and obtain the current offset of the blade centerline. Adjust the spherical body so that the blade centerline coincides with the axis of the rotating motor power output shaft.

[0027] S3. Initialization and parameter configuration of the dual-line laser sensor group: Based on the inherent parameters of the aero-engine blade to be detected, the first line laser sensor group and the second line laser sensor group are set on the circular track, and the angle between the first line laser sensor group, the second line laser sensor group and the center of the circular track is less than the maximum torsion angle of the aero-engine blade.

[0028] S4. Detection path planning: Input the model of the aero-engine blade to be detected into the processor and generate the detection trajectory of the line laser sensor group;

[0029] S5. The dual-line laser sensor group performs synchronous scanning and data acquisition. The first and second line laser sensor groups simultaneously emit lasers toward the blades of the aero-engine and simultaneously receive and acquire point clouds P1 and P2.

[0030] S6. Point cloud preprocessing and coordinate system one: Denoise the collected point cloud, and use the common center line of the first line laser sensor group and the second line laser sensor group as the global coordinate system, and synchronize the denoised point cloud data to the global coordinate system.

[0031] S7. Point cloud fusion and leaf contour extraction: fuse the denoised point cloud data, perform surface fitting on the fused point cloud, extract the leaf edge curve, and calculate the leaf edge thickness and rounded corner from the leaf edge curve;

[0032] S8. Blade characteristic error assessment and result output: Compare the obtained aero-engine blade parameters with the theoretical values ​​of the input aero-engine blade model, calculate the RMS error, and determine whether it is qualified.

[0033] Furthermore, the first line laser sensor group uses blue light with a wavelength of 405nm, and the second line laser sensor group uses blue light with a wavelength of 450nm.

[0034] The beneficial effects of the present invention include at least one of the following:

[0035] 1. At the system level, the technical solution provided in this application uses a detection mechanism including multiple line laser sensor groups, combined with an inner rotation mechanism and an outer surround mechanism, to perform positioning detection on aero-engine blades, especially fan blades. The inner rotation mechanism can not only provide the necessary blade self-rotation during detection, but also correct the offset of the fan blade centerline. The outer surround mechanism is used to adjust the position of multiple line laser sensor groups for fan blades of different batches and different torsion degrees. The multiple line laser sensor groups cover the rounded corner area of ​​the fan blade edge with complementary angles during detection, avoiding the optical path offset and positioning drift caused by traditional moving sensors.

[0036] 2. Simultaneously adopting the "fixed sensor + rotating blade" architecture, it not only retains the spatial complementarity of the multi-line laser sensor, but also expands the coverage of the single-line laser sensor on the tortuous blade through rotation, providing stable geometric conditions for continuous detection in high curvature areas.

[0037] 3. At the methodological level, the synchronous scanning and collaborative operation of multiple line laser sensor groups achieves a balance between accuracy and efficiency. The synergy between dual-laser synchronous scanning and the curvature adaptive strategy also achieves this balance. In scanning path planning, curvature parameters are extracted from the blade CAD model. During dual-laser synchronous triggering, signals are separated by combining dual-line laser receivers and wavelength filters to avoid crosstalk. In point cloud processing, the common centerline of the line laser sensors is first used as the global coordinate system. Point clouds are aligned, overlapping areas of planar projections are then fused, and finally, surface fitting is used to extract the blade edge curve. In the error evaluation stage, contour error, torsion angle error, etc., combined with the output results of the grading standards, achieve full-parameter closed-loop verification.

[0038] 4. The system and method are deeply coupled. Multiple line laser sensor groups on the outer ring mechanism ensure the stability of the optical path, the inner rotating mechanism adapts to blade twisting and offset, multiple lasers complementarity suppress scattering, and point cloud fusion and fitting fill the blind zone of single lasers. This significantly improves the detection consistency and process adaptability of aero-engine fan blades, especially the blade edge profile, thickness and twist angle. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of an aero-engine blade structure;

[0040] Figure 2 for Figure 1 A schematic diagram of scattering when detecting on one side of region A in the middle;

[0041] Figure 3 This is a schematic diagram of a blade positioning and detection system for an aero-engine.

[0042] Figure 4 A schematic diagram of a blade positioning and detection system for an aero-engine from another perspective;

[0043] Figure 5 This is a schematic diagram of the mounting base structure;

[0044] Figure 6 This is a schematic diagram of the rotary table structure;

[0045] Figure 7 This is a structural diagram of the mounting base, connecting rod, and spherical body.

[0046] In the picture:

[0047] 1 is the first line laser sensor group, 2 is the second line laser sensor group, 3 is the mounting base, 4 is the blade for aero-engines, 5 is the rotating base, 6 is the annular track, 7 is the tenon head, 8 is the screw, 9 is the mounting groove, 10 is the abutment, 11 is the connecting rod, 12 is the sphere, and 13 is the opening. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described in the accompanying drawings can generally be arranged and designed in various different configurations.

[0049] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0050] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0051] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0052] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0053] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0054] like Figure 3 and Figure 4 The aforementioned blade positioning and detection system for an aero-engine includes a blade positioning mechanism, an inner rotation mechanism, an outer circling mechanism, and a detection mechanism.

[0055] The blade positioning mechanism for the aero-engine can be used to install the aero-engine blade 4 and can adjust the angle of the aero-engine blade 4.

[0056] The internal rotation mechanism is located below the blade positioning mechanism for aero-engines and can drive the blade positioning mechanism for aero-engines to rotate around the central axis.

[0057] The outer surrounding mechanism is located on the outer periphery of the inner rotating mechanism and is used to install the detection mechanism;

[0058] The detection mechanism includes multiple line laser sensor groups and a processor. The multiple line laser sensor groups are arranged around the outer periphery of the blade positioning mechanism for aero-engines and can collect image data of the aero-engine blades. The processor is used to process the image data collected by the multiple line laser sensor groups and generate detection results.

[0059] The purpose of this design is that, at the system level, the technical solution provided in this application uses a detection mechanism including multiple line laser sensor groups, combined with an inner rotation mechanism and an outer surround mechanism, to perform positioning detection on aero-engine blades, especially fan blades. The inner rotation mechanism not only provides the necessary blade self-rotation during detection but also corrects the offset of the fan blade centerline. The outer surround mechanism is used to adjust the position of multiple line laser sensor groups for fan blades of different batches and different torsion degrees. The multiple line laser sensor groups cover the rounded corner area of ​​the fan blade edge with complementary angles during detection, avoiding the optical path offset and positioning drift caused by traditional moving sensors.

[0060] like Figure 7 As shown, the blade positioning mechanism for aero-engines includes a mounting base 3, a connecting rod 11, and a spherical body 12;

[0061] The aero-engine blade 4 can be mounted on the mounting base 3, and the vertical projection of the aero-engine blade 4 covers the center of the mounting base 3.

[0062] One end of the connecting rod 11 is connected to the center of the bottom of the mounting base 3, and the other end of the connecting rod 11 is connected to the spherical body 12.

[0063] The spherical body 12 can be placed in the inner rotating mechanism.

[0064] At the same time, such as Figure 6 As shown, the inner rotating mechanism includes a rotating seat 5 and a base. A rotating motor is installed on the base. The rotating seat 5 is mounted on the base and connected to the power output shaft of the rotating motor, rotating under the drive of the rotating motor.

[0065] Furthermore, the top of the rotating seat 5 is provided with an opening 13, and a limiting structure is provided inside the rotating seat 5. The spherical body 12 can be placed inside the rotating seat 5 and limited by the limiting structure, and the connecting rod 11 can pass through the opening 13.

[0066] In practical use, the spherical object is first placed inside the rotating seat. A movable door can be set on one side of the rotating seat for it to be inserted, and a limiting structure is set inside the movable door. After the spherical object is inserted, it can be limited and fixed by the limiting structure. The specific structure can be that the upper part is a buffer pad and the lower part is also a buffer pad, in which the spherical object can be clamped. Then, a lifting component is set at the bottom of the lower buffer pad. This lifting component can be a stop plate combined with a worm gear and a worm. The stop plate is raised or lowered by rotating the worm gear externally, thereby limiting the spherical object. Of course, those skilled in the art can also refer to the prior art, such as Chinese patent with announcement number CN202972399U, which discloses a spherical gimbal locking ring and a spherical gimbal, using a washer combined with an inclined conical surface for adjustment and limiting.

[0067] After the sphere is positioned, the connecting rod is passed through the opening to connect with the sphere. This connection can be a threaded connection. In some applications, the sphere and the connecting rod can be integrated into one structure. However, this structure needs to be smaller than the opening size during installation so that it can be inserted into the rotating seat from the opening. But this method requires changing the positioning structure and using the side or other existing methods for positioning.

[0068] After the connecting rod is installed, a mounting bracket is then installed on one side of the connecting rod, such as... Figure 5 As shown, the structure of the mounting base is such that the top of the mounting base 3 is provided with a mounting groove 9, and the mounting groove 9 passes through the center of the mounting base 3, and a stop block 10 is provided at the opening on one side of the mounting groove 9;

[0069] The tenon 7 of the aero-engine blade 4 can be abutted into the mounting groove 9 from one side by the abutment 10;

[0070] The abutment 10 is provided with screws 8, and is detachably connected to the mounting base 3 by means of screws 8.

[0071] In practical use, the tenon of the aircraft engine blade is first inserted into the mounting groove and connected to the end of the mounting groove. Then, the abutment is placed at the opening at the other end of the mounting groove and connected with screws. In terms of the material selection of the abutment, a flexible material can be selected, so that it can limit the tenon while minimizing its compression and wear.

[0072] It should also be noted that since the mounting base rotates on a horizontal plane throughout the entire testing process, this type of block limiting is sufficient to fix the tenon head. At the same time, when the centerline offset is adjusted, the mounting base and the aero-engine blade will tilt. To avoid the mounting base blocking the line laser sensor group during tilting, the depth of the mounting groove is less than the height of the tenon head, so that the airfoil surface of the aero-engine blade can be fully exposed.

[0073] In this embodiment, the outer surrounding mechanism includes an annular track 6 and a sliding seat. The annular track 6 is located on the outer periphery of the rotating seat 5, and the center of the annular track 6 coincides with the center of the rotating seat 5. The sliding seat is located on the annular track 6 and can move on the annular track 6. The sliding seat is used to install the line laser sensor group.

[0074] Meanwhile, the detection mechanism includes a first line laser sensor group 1 and a second line laser sensor group 2, and both the first line laser sensor group 1 and the second line laser sensor group 2 are mounted on a sliding seat and face the center of the annular track 6. The angle between the first line laser sensor group 1, the second line laser sensor group 2 and the center of the annular track 6 is less than the maximum torsion angle of the aero-engine blade 4.

[0075] The purpose of this design is that the outer surround mechanism is used to adjust the position of multiple line laser sensor groups for fan blades of different batches and different degrees of twist. The multiple line laser sensor groups cover the rounded corner area of ​​the fan blade edge with complementary angles during detection, avoiding the optical path offset and positioning drift caused by traditional moving sensors.

[0076] In this embodiment, a method for positioning and detecting aero-engine blades based on an aero-engine blade positioning and detection system is also provided, including the following steps:

[0077] S1. Installation of the rotating seat: Install the rotating seat 5 on the power output shaft of the rotating motor, place the spherical body 12 inside the rotating seat 5, insert the connecting rod 11 from the opening 13, and connect one end of the connecting rod 11 to the spherical body 12 and the other end of the connecting rod 11 to the mounting seat 3.

[0078] S2. Blade positioning and attitude adjustment: Place the aero-engine blade 4 to be tested on the mounting base 3, and ensure that the tenon 7 of the aero-engine blade 4 is in contact with the top surface of the mounting base 3. Take an image of the aero-engine blade 4, obtain the current blade centerline offset of the aero-engine blade 4, and adjust the spherical body 12 so that the blade centerline coincides with the axis of the rotating motor power output shaft.

[0079] S3. Initialization and parameter configuration of the dual-line laser sensor group: Based on the inherent parameters of the aero-engine blade 4 to be detected, the first line laser sensor group 1 and the second line laser sensor group 2 are set on the annular track 6, and the angle between the first line laser sensor group 1, the second line laser sensor group 2 and the center of the annular track 6 is less than the maximum torsion angle of the aero-engine blade 4.

[0080] S4. Detection path planning: Input the model of the blade 4 of the aero-engine to be detected into the processor and generate the detection trajectory of the line laser sensor group;

[0081] S5. The dual-line laser sensor group performs synchronous scanning and data acquisition. The first line laser sensor group 1 and the second line laser sensor group 2 simultaneously emit lasers toward the blade 4 of the aero-engine and simultaneously receive and acquire point clouds P1 and P2.

[0082] S6. Point cloud preprocessing and coordinate system one: Denoise the collected point cloud, and use the common center line of the first line laser sensor group 1 and the second line laser sensor group 2 as the global coordinate system, and synchronize the denoised point cloud data to the global coordinate system.

[0083] S7. Point cloud fusion and leaf contour extraction: fuse the denoised point cloud data, perform surface fitting on the fused point cloud, extract the leaf edge curve, and calculate the leaf edge thickness and rounded corner from the leaf edge curve;

[0084] S8. Blade characteristic error assessment and result output: Compare the obtained parameters of the aero-engine blade 4 with the theoretical values ​​of the model of the aero-engine blade 4 to be tested, calculate the RMS error, and determine whether it is qualified.

[0085] In a specific application scenario, a blade for a certain type of aero-engine to be tested is selected. Its material is Ti-6Al-4V, the blade height is 200mm, the chord length is 75mm, the twist is 30°, and the centerline offset angle is 4°.

[0086] After completing steps S1 and S2, a first line laser sensor group 1 and a second line laser sensor group 2 are installed on the annular track 6. The first line laser sensor group 1 uses blue light with a wavelength of 405nm and an incident angle of 35°, while the second line laser sensor group 2 uses blue light with a wavelength of 450nm and an incident angle of 55°. Therefore, the observation angle between the first line laser sensor group 1 and the second line laser sensor group 2 is 20°, which is less than the torsion of the aero-engine blade to be tested. At the same time, the first line laser sensor group 1 and the second line laser sensor group 2 are 250mm away from the aero-engine blade to be tested at the center of the annular track 6. The use of lasers with different wavelengths allows for signal separation through wavelength filters, avoiding crosstalk.

[0087] Then, the first line laser sensor group 1 and the second line laser sensor group 2 are activated, or an external industrial camera is used to acquire the contour of the blade of the aero-engine to be inspected. The centerline offset of the blade to be inspected is identified by the existing OpenCV contour matching algorithm. Then, the mounting base is adjusted by a robotic arm or manually to offset the angle around the sphere, so that the centerline of the blade to be inspected is perpendicular to the horizontal plane.

[0088] Next, input the CAD model of the aero-engine blade to be tested, including the blade profile curve. and twist angle distribution The X-axis is set along the direction from the blade root to the blade tip of the aero-engine blade under inspection after adjustment. Scanning segments are divided according to curvature adaptive step size: step size s = 0.05 mm in areas of high curvature and s = 0.1 mm in other areas. The rotational angular velocity of the aero-engine blade under inspection is set to... This is to ensure that the point cloud density acquired by the first line laser sensor group 1 and the second line laser sensor group 2 meets the resolution requirements.

[0089] In this way, the step size between scanning points is dynamically adjusted according to the curvature of different areas on the leaf surface. The larger the curvature, the more severe the curvature, the smaller the step size, and the denser the scanning points. The smaller the curvature, the flatter the area, the larger the step size, and the sparser the scanning points. Taking the leaf edge as an example, if the step size is too large during scanning, point cloud discontinuity will occur, and the outline of the rounded corner will not be captured.

[0090] In the synchronous scanning and point cloud acquisition of the first-line laser sensor group 1 and the second-line laser sensor group 2, the point cloud acquired by the first-line laser sensor group 1 is denoted as P1, and P1 = ;

[0091] The point cloud acquired by the second-line laser sensor group 2 is denoted as P2, and P2 = ;

[0092] Where i is the index of the i-th point collected by the first line laser sensor 1, j is the index of the j-th point collected by the second line laser sensor 2, n represents the total number of points collected by the first line laser sensor group 1, i traverses all collection points from 1 to n, m represents the total number of points collected by the second line laser sensor group 2, and j traverses all collection points from 1 to m.

[0093] After point cloud acquisition, denoising is performed to remove outliers in point cloud sets P1 and P2 that exceed the theoretical thickness of the leaf edge, as shown in the following formula:

[0094] ;

[0095] in It is the original point cloud collection that needs to be denoised;

[0096] It is an abstract representation of a single point in a point cloud;

[0097] It is a point Coordinate value in the Z-axis direction;

[0098] , Indicates the upper and lower limits of the leaf edge error range.

[0099] Next, the common center line of the first line laser sensor group 1 and the second line laser sensor group 2 is used as the global coordinate system O-XYZ. Based on the ICP algorithm, the point cloud set P1 and the point cloud set P2 are aligned to the global coordinate system, and the units are unified.

[0100] It should be noted that there are corresponding public disclosures in the existing technology regarding point cloud acquisition and contour extraction and determination. The technical solution provided in this embodiment is more about enhancing the detection of the rounded corner contour area of ​​the leaf edge from the perspective of the dual-line laser sensor group.

[0101] Point cloud fusion and leaf edge fillet contour reconstruction of the dual-line laser sensor group are performed. For the overlapping area of ​​point cloud set P1 and point cloud set P2 in the XY plane projection, the average Z value is taken to complete the contour, as shown in the following formula:

[0102] ;

[0103] And when Fusion is performed in real time to avoid incorrect matching when there are significant differences. Set an error value for the height difference.

[0104] Next, the point cloud is fused by NURBS surface fitting, the leaf edge curve is extracted, and fitting is performed within the set fitting error.

[0105] Finally, the error between the collected parameters and the theoretical values ​​of the blades used in the tested aero-engine was analyzed, and the point cloud after fitting the blade edge profile was analyzed. The minimum distance d from each measuring point to the theoretical curve is calculated along the normal direction of the theoretical airfoil curve, and the fillet profile error is defined as:

[0106] ;

[0107] when It is considered qualified when it is less than or equal to the typical tolerance of aero-engine blades.

[0108] Extract the chord line of the airfoil section to be tested, that is, connect the midpoints of the leading and trailing edges, and calculate the difference in torsion angle between it and the theoretical chord line. :

[0109] ;

[0110] when It is considered qualified when the torsion angle is less than or equal to the typical torsion angle tolerance of aero-engine blades.

[0111] Finally, the fitted point cloud was detected. The model of the blade 4 of the aircraft engine to be tested is transparently overlaid, and the error distribution is marked by color mapping. The model of the blade 4 of the aircraft engine to be tested can be a CAD model.

[0112] At the methodological level, the synchronous scanning and collaborative operation of multiple line laser sensor groups achieves a balance between accuracy and efficiency. The synergy between dual-laser synchronous scanning and curvature adaptive strategies also achieves this balance. In scanning path planning, curvature parameters are extracted from the blade CAD model. During dual-laser synchronous triggering, signals are separated by combining dual-line laser receivers and wavelength filters to avoid crosstalk. In point cloud processing, the common centerline of the line laser sensors is used as the global coordinate system. Point clouds are aligned, overlapping areas of planar projections are fused, and finally, surface fitting is used to extract the blade edge curve. In the error evaluation stage, contour error, torsion angle error, etc., combined with the output results of grading standards, achieve full-parameter closed-loop verification. The system and method are deeply coupled. Multiple line laser sensor groups on the outer surrounding mechanism ensure optical path stability, the inner rotating mechanism adapts to blade torsion and offset, multi-laser complementarity suppresses scattering, and point cloud fusion and fitting fill the single-laser blind zone, significantly improving the detection consistency and process adaptability of aero-engine fan blades, especially the blade edge contour, thickness, and torsion angle.

[0113] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A blade positioning and detection system for an aero-engine, characterized in that, This includes blade positioning mechanisms, inner rotation mechanisms, outer surround mechanisms, and testing mechanisms for aero-engines; The blade positioning mechanism for the aero-engine can be used to install aero-engine blades (4) and can adjust the angle of the aero-engine blades (4); The internal rotation mechanism is located below the blade positioning mechanism for aero-engines and can drive the blade positioning mechanism for aero-engines to rotate around the central axis. The outer surrounding mechanism is located on the outer periphery of the inner rotating mechanism and is used to install the detection mechanism; The detection mechanism includes multiple line laser sensor groups and a processor. The multiple line laser sensor groups are arranged around the outer periphery of the blade positioning mechanism for aero-engines and can collect image data of the blades (4) for aero-engines. The processor is used to process the image data collected by the multiple line laser sensor groups and generate detection results. The blade positioning mechanism for aero-engines includes a mounting base (3), a connecting rod (11), and a spherical body (12). The aero-engine blade (4) can be mounted on the mounting base (3), and the vertical projection of the aero-engine blade (4) covers the center of the mounting base (3); One end of the connecting rod (11) is connected to the center of the bottom of the mounting base (3), and the other end of the connecting rod (11) is connected to the sphere (12); The spherical object (12) can be placed in the inner rotating mechanism; The internal rotating mechanism includes a rotating seat (5) and a base. A rotating motor is provided on the base. The rotating seat (5) is installed on the base and connected to the power output shaft of the rotating motor, and rotates under the drive of the rotating motor. The outer surrounding mechanism includes an annular track (6) and a sliding seat. The annular track (6) is located on the outer periphery of the rotating seat (5), and the center of the annular track (6) coincides with the center of the rotating seat (5). The sliding seat is located on the annular track (6) and can move on the annular track (6). The sliding seat is used to install the line laser sensor group. The detection mechanism includes a first line laser sensor group (1) and a second line laser sensor group (2), and both the first line laser sensor group (1) and the second line laser sensor group (2) are mounted on a sliding seat and face the center of the circular track (6). The angle between the first line laser sensor group (1), the second line laser sensor group (2) and the center of the circular track (6) is less than the maximum twist angle of the aero-engine blade (4).

2. The blade positioning and detection system for an aero-engine according to claim 1, characterized in that, The mounting base (3) is provided with a mounting groove (9) at the top, and the mounting groove (9) passes through the center of the mounting base (3). A stop block (10) is provided at the opening on one side of the mounting groove (9). The tenon (7) of the aero-engine blade (4) can be abutted into the mounting groove (9) from one side by abutting block (10); The abutment (10) is provided with screws (8) and is detachably connected to the mounting base (3) by means of screws (8).

3. The blade positioning and detection system for an aero-engine according to claim 1, characterized in that, The rotating seat (5) has an opening (13) at the top and a limiting structure inside. The spherical body (12) can be placed inside the rotating seat (5) and limited by the limiting structure. The connecting rod (11) can pass through the opening (13).

4. A method for positioning and detecting blades for aero-engines, implemented based on the positioning and detecting system for aero-engines as described in claim 1, characterized in that, Includes the following steps: S1. Installation of the rotating seat: Install the rotating seat (5) on the power output shaft of the rotating motor, place the spherical body (12) inside the rotating seat (5), insert the connecting rod (11) from the opening (13), and connect one end of the connecting rod (11) to the spherical body (12) and the other end of the connecting rod (11) to the mounting seat (3); S2. Blade positioning and attitude adjustment: Place the aero-engine blade (4) to be tested on the mounting base (3) and ensure that the tenon (7) of the aero-engine blade (4) is in contact with the top surface of the mounting base (3). Take an image of the aero-engine blade (4) and obtain the current offset of the blade centerline of the aero-engine blade (4). Adjust the sphere (12) so that the blade centerline coincides with the axis of the rotating motor power output shaft. S3. Initialization and parameter configuration of the dual-line laser sensor group: Based on the inherent parameters of the aero-engine blade (4) to be detected, the first line laser sensor group (1) and the second line laser sensor group (2) are set on the circular track (6), and the angle between the first line laser sensor group (1), the second line laser sensor group (2) and the center of the circular track (6) is less than the maximum twist angle of the aero-engine blade (4); S4. Detection path planning: Input the model of the aero-engine blade (4) to be detected into the processor and generate the detection trajectory of the line laser sensor group; S5. Synchronous scanning and data acquisition by dual-line laser sensor groups: The first line laser sensor group (1) and the second line laser sensor group (2) synchronously emit lasers toward the blades (4) of the aero-engine and synchronously receive and collect point clouds. P 1 and P 2; S6. Point cloud preprocessing and coordinate system one: Denoise the collected point cloud, and use the common center line of the first line laser sensor group (1) and the second line laser sensor group (2) as the global coordinate system, and synchronize the denoised point cloud data to the global coordinate system; S7. Point cloud fusion and leaf contour extraction: fuse the denoised point cloud data, perform surface fitting on the fused point cloud, extract the leaf edge curve, and calculate the leaf edge thickness and rounded corner from the leaf edge curve; S8. Blade feature error assessment and result output: Compare the parameters of the aero-engine blade (4) obtained by the test with the theoretical values ​​of the model of the aero-engine blade (4) to be tested, calculate the RMS error, and determine whether it is qualified.

5. The method for positioning and detecting blades for aero-engines according to claim 4, characterized in that, The first line laser sensor group (1) uses blue light with a wavelength of 405nm, and the second line laser sensor group (2) uses blue light with a wavelength of 450nm.

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