Self-adaptive laser deposition repairing method and system for defective blade of water turbine

Abstract

The invention discloses a self-adaptive laser deposition repairing method and system for a defective blade of a water turbine, and relates to the field of laser additive manufacturing, and the self-adaptive laser deposition repairing method comprises the steps that S1, the defective blade is measured, and a contour measuring point of the defective blade is obtained; s2, performing curved surface reconstruction based on the contour measurement points of the defective blade to obtain a defective blade model; s3, the defect area of the defect blade model is repaired through the defect-free area of the defect blade model, and a repaired defect blade model is obtained; and S4, based on the defective blade repairing model, laser is adopted for conducting self-adaptive laser deposition machining on the defective blade, and the repaired blade is obtained. According to the method, smooth recovery of the curved surface of the defective blade can be guaranteed, and the precision is high.

Description

Technical Field

[0001] This invention relates to the field of laser additive manufacturing technology, and in particular to an adaptive laser deposition repair method and system for defective turbine blades. Background Technology

[0002] Turbine blades are high-precision components. The accuracy of the blade surface profile plays a decisive role in their performance, and even slight variations in the blade profile can lead to significant changes in performance. During blade operation, different types of blade defects typically include fracture, surface damage, erosion, and cracks, resulting in incomplete blade surfaces. Furthermore, blades can deform completely under the impact of water flow, rendering nominal models unrepairable. Therefore, blade repair based on measurement points becomes an important issue.

[0003] Currently, most research on the repair of bent or twisted blades falls into three categories. The first method is based on the reconstruction of the cross-sectional curve. However, this method is only suitable for repairing small-scale defect areas. The second method is based on the reconstruction and adaptive repair of the defective blade surface. This method can select multiple control points during surface expansion, thus introducing high uncertainty in repairing wear blades with large-scale damaged areas. In addition to the above two repair categories, some other novel algorithms have been used to repair blade surfaces. While these have improved the efficiency of blade repair to some extent, they are complex and imprecise in practice.

[0004] Some studies have used point clouds for repair, extracting reference points from the point cloud to repair the cross-sectional curve, or directly repairing the blade surface using the point cloud. However, without a theoretical CAD model and blade engineering documentation, any blade repair method is essentially guesswork. Current "guessing" repair methods seem unreliable, leading to significant uncertainty in the repaired blade model. Furthermore, the uncertainty in model repair cannot guarantee the accuracy of the repaired model. Summary of the Invention

[0005] To address the technical problems existing in the background art, this invention proposes an adaptive laser deposition repair method and system for defective turbine blades.

[0006] In a first aspect, the present invention proposes an adaptive laser deposition repair method for defective turbine blades, comprising: S1. Measure the defective blade to obtain the contour measurement points of the defective blade; S2. Based on the contour measurement points of the defective blade, surface reconstruction is performed to obtain the defective blade model; S3. Use the defect-free area of ​​the defective blade model to repair the defective area of ​​the defective blade model to obtain the repaired defective blade model. S4. Based on the defective blade model, the defective blade is adaptively processed using laser to obtain the repaired blade.

[0007] Preferably, in S1, the defective blade is measured to obtain the contour measurement points of the defective blade, specifically including: measuring the defective blade using a coordinate measuring machine or a scanning method to obtain the contour measurement points of the defective blade.

[0008] Preferably, in S3, the defective area of ​​the defective blade model is repaired using the defect-free area of ​​the defective blade model to obtain a repaired defective blade model, specifically including: S31. Divide the entire defective blade model along the height direction of the defective blade to obtain multiple slice layers; based on the defective area of ​​the defective blade model, determine the defective slice layer from the multiple slice layers, and use the outline of the defective slice layer as the defect cross-section curve; use the outline of the defect-free slice layer adjacent to the first defective slice layer located in the preset repair direction as the initial reference curve. S32. Based on the reference curve, repair the cross-sectional curve of the defect adjacent to the reference curve to obtain the repaired cross-sectional curve; S33. Determine whether the repair section curve has adjacent defect cross-sectional curves; If so, proceed to S34; If not, then the process ends, completing the repair of all defect cross-sectional curves in the defect area; S34. Use the repair section curve as the reference curve and proceed to S32.

[0009] Preferably, in step S32, the defect cross-sectional curve adjacent to the reference curve is repaired according to the reference curve to obtain the repaired cross-sectional curve, specifically including: S321. The reference curve and the defect cross-section curve adjacent to the reference curve are sampled by the equidistant sampling method. The multiple discrete points of the sampled reference curve are used as the control point set of the reference curve, and the multiple discrete points of the sampled defect cross-section curve are used as the measurement point set of the defect cross-section curve. S322. The control point set of the reference curve and the measurement point set of the defect cross section curve are rigidly registered to obtain the rotation matrix and translation matrix. S323. Perform B-spline curve fitting on the control point set of the reference curve and the defect cross-section curve adjacent to the reference curve to obtain the reference B-spline curve and the defect B-spline curve. S324. Based on the rotation matrix and translation matrix, apply an affine transformation to the defect B-spline curve to map it to the reference B-spline curve, and obtain the aligned defect B-spline curve. S325. Deform the aligned defect B-spline curve so that the shape of the deformed defect B-spline curve and the shape error of the reference B-spline curve meet the preset error, and use the defect B-spline curve that meets the preset error as the repair section curve.

[0010] Preferably, in S322, the control point set of the reference curve and the measurement point set of the defect cross-section curve are rigidly registered to obtain a rotation matrix and a translation matrix, specifically including: S3221. Based on the control point set of the reference curve and the measurement point set of the defect cross section curve, establish the mapping relationship between the control points of the reference curve and the measurement points of the defect cross section curve. S3222. Based on the mapping relationship between the control points of the reference curve and the measurement points of the defect cross-section curve, calculate the offset of the control point set of the reference curve; based on the offset of the control point set of the reference curve and the preset local confidence weight, update the control point set of the reference curve; perform coarse registration between the control point set of the reference curve and the measurement point set of the defect cross-section curve to obtain the initial rotation matrix and translation matrix. S3223. Based on the control point set of the reference curve and the initial rotation and translation matrices, the measurement point set of the intermediate repair section curve is obtained; S3224. Calculate the average distance function between the measurement point set of the intermediate repair section curve and the measurement points of the defect cross section curve; S3225. Determine whether the value of the average distance function is less than the preset average distance function threshold; if so, stop the calculation and obtain the final translation matrix and rotation matrix. If not, proceed to S3226: S3226. Transform the translation and rotation matrices; update the control point set of the reference curve based on the transformed translation and rotation matrices, and update the reference curve based on the updated control point set of the reference curve, and then proceed to S3223.

[0011] Preferably, a mapping relationship between the control points of the reference curve and the measurement points of the defect cross-section curve is established based on the control point set of the reference curve and the measurement point set of the defect cross-section curve, specifically including: The measurement point set of the defect cross-section curve is preprocessed and uniformly parameterized to obtain the parameter sequence of the defect cross-section curve. Based on the node vector of the reference curve, the parameter sequence of the defect cross section curve is aligned by node mapping. Construct a configuration matrix based on the node vector of the reference curve; Using a B-spline-based cross-sectional curve interpolation algorithm, the measurement point set of the aligned defect cross-section curve is fitted with the nodal vector of the reference curve using least squares, resulting in virtual control points that correspond one-to-one with the control points of the defect cross-section curve and the reference curve. Based on virtual control points that correspond one-to-one with the control points of the defect cross-section curve and the reference curve, a one-to-one mapping relationship is established between the control points of the reference curve and the measurement points of the defect cross-section curve.

[0012] Preferably, based on the control point set of the reference curve and the initial rotation and translation matrices, the measurement point set of the intermediate repair section curve is obtained, specifically including: Using the initial translation and rotation matrices, the measurement point set of the defect cross section curve is transformed to the coordinate system of the reference curve to complete the coarse alignment; Using a cross-sectional curve interpolation algorithm based on B-splines, the measurement point set of the coarsely aligned defect cross-section curve is fitted with the nodal vector of the reference curve using least squares, resulting in virtual control points that correspond one-to-one with the control points of the defect cross-section curve and the reference curve. Using the defect in the cross-section curve as the deformation driving force, the measurement points of the cross-section curve are reconstructed by weighting based on the virtual control points of the cross-section curve, resulting in the intermediate repair section curve and the set of measurement points of the intermediate repair section curve.

[0013] In S3222, based on the relationship between the control point set of the reference curve and the measurement points of the defect cross-section curve adjacent to the reference curve, coarse registration is performed on the control point set of the reference curve and the measurement point set of the defect cross-section curve adjacent to the reference curve to obtain the initial rotation matrix and translation matrix, specifically including: The reference curve and the defect cross-section curve are discretized respectively, and the first centroid of the discretized reference curve relative to the discrete point and the second centroid of the discretized defect cross-section curve relative to the discrete point are calculated respectively. The translation matrix between the first centroid and the second centroid is established. Directional features were extracted from the reference curve and the defect cross-section curve, respectively; the directional features included: the center point of the inner arc, the center point of the exit arc, the chord length, and the maximum thickness of the blade. Based on the directional characteristics of the reference curve and the defect cross-section curve, establish the directional relationship between the directional characteristics of the reference curve and the defect cross-section curve; Based on the directional relationship between the reference curve and the defect cross-section curve, a rotation matrix between the reference curve and the defect cross-section curve is established with the first centroid and the second centroid as the origin, respectively.

[0014] In S325, the aligned defect B-spline curve is deformed so that the shape error between the deformed defect B-spline curve and the reference B-spline curve meets a preset error, specifically including: When the defect of the aligned defect B-spline curve meets the preset small defect conditions, the control points corresponding to the defect area of ​​the defect B-spline curve are locally replaced by the control points of the reference B-spline curve. If the defect of the aligned defect B-spline curve meets the preset large defect condition or complex defect condition, a smooth deformation field is constructed between the reference B-spline curve and the aligned defect B-spline curve, and a weighting function is introduced to control the deformation intensity of the aligned defect B-spline curve, and the control points of the defect B-spline curve are updated so that the shape error between the deformed defect B-spline curve and the shape error of the reference B-spline curve meets the preset error.

[0015] Preferably, based on the defective blade repair model, the defective blade is adaptively processed using laser to obtain the repaired blade, specifically including: Based on the defective blade model, laser deposition is used to adaptively process the defective blade to obtain the repaired blade.

[0016] Preferably, in the adaptive processing of defective blades using laser deposition, the defective area of ​​the defective blade is first remelted and heated multiple times using a laser, and then powder is deposited on the remelted and heated defective area using a laser. After the deposition is completed, the defective area after powder deposition is scanned by a laser at preset time intervals within a preset time period.

[0017] Secondly, this invention also proposes an adaptive laser deposition repair system for defective turbine blades, comprising: The measurement module is used to measure the defective blade and obtain the contour measurement points of the defective blade; The reconstruction module is used to reconstruct the surface based on the contour measurement points of the defective blade to obtain the defective blade model; The model repair module is used to repair the defective areas of the defective blade model using the defect-free areas of the defective blade model, so as to obtain a repaired defective blade model. The laser module is used to adaptively process the defective blades using lasers based on the defective blade repair model, so as to obtain the repaired blades.

[0018] Preferably, the defective areas of the defective blade model are repaired using the defect-free areas of the defective blade model to obtain a repaired defective blade model, specifically including: The entire defective blade model is divided along the height direction of the defective blade to obtain multiple slice layers. Based on the defective area of ​​the defective blade model, the defective slice layer is determined from the multiple slice layers, and the outline of the defective slice layer is used as the defect cross-section curve. The outline of the non-defective slice layer adjacent to the first defective slice layer located in the preset repair direction is used as the initial reference curve. Based on the reference curve, the defect cross-sectional curves adjacent to the reference curve are repaired to obtain the repaired cross-sectional curve; it is determined whether the repaired cross-sectional curve has an adjacent defect cross-sectional curve; if not, the repair of all defect cross-sectional curves in the defect area is completed; if so, the repaired cross-sectional curve is used as the reference curve, and registration and repair are performed again until the repair of all defect cross-sectional curves in the defect area is completed.

[0019] Preferably, based on the reference curve, the defect cross-sectional curve adjacent to the reference curve is repaired to obtain the repaired cross-sectional curve, specifically including: The equidistant sampling method is used to sample the reference curve and the defect cross-section curve adjacent to the reference curve. The multiple discrete points of the sampled reference curve are used as the control point set of the reference curve, and the multiple discrete points of the sampled defect cross-section curve are used as the measurement point set of the defect cross-section curve. The rotation matrix and translation matrix are obtained by rigidly registering the control point set of the reference curve and the measurement point set of the defect cross section curve. B-spline curves are fitted to the control point set of the reference curve and the defect cross-section curve adjacent to the reference curve to obtain the reference B-spline curve and the defect B-spline curve. Based on the rotation and translation matrices, an affine transformation is applied to the defect B-spline curve to map it to the reference B-spline curve, resulting in the aligned defect B-spline curve. The aligned defect B-spline curve is deformed so that the shape of the deformed defect B-spline curve and the shape error of the reference B-spline curve meet the preset error, and the defect B-spline curve that meets the preset error is used as the repair section curve.

[0020] The proposed adaptive laser deposition repair method for defective turbine blades involves measuring the defective blade to obtain its contour measurement points; reconstructing the surface based on these contour measurement points to obtain a defective blade model; repairing the defective areas of the defective blade model using the defect-free areas of the model; and then performing adaptive laser deposition processing on the repaired model using a laser to obtain the repaired blade. This method ensures the smooth restoration of the defective blade surface and achieves high precision. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the adaptive laser deposition repair method for defective turbine blades in one embodiment of the present invention.

[0022] Figure 2 for Figure 1 The intent of the S3 process in the document. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] Firstly, referring to Figure 1 The present invention proposes an adaptive laser deposition repair method for defective turbine blades, comprising: S1. Measure the defective blade to obtain the contour measurement points of the defective blade; S2. Based on the contour measurement points of the defective blade, surface reconstruction is performed to obtain the defective blade model; S3. Use the defect-free area of ​​the defective blade model to repair the defective area of ​​the defective blade model to obtain the repaired defective blade model. S4. Based on the defective blade model, the defective blade is adaptively processed using laser to obtain the repaired blade.

[0025] This invention measures a defective blade to obtain its contour measurement points; reconstructs the surface based on these points to obtain a defective blade model; repairs the defective areas of the defective blade model using the defect-free areas, resulting in a repaired defective blade model; and performs adaptive laser deposition on the repaired blade model to obtain a repaired blade. This process ensures the smooth restoration of the defective blade surface and achieves high precision. In one specific embodiment, in S1, the defective blade is measured to obtain the contour measurement points of the defective blade, specifically including: measuring the defective blade using a coordinate measuring machine to obtain the contour measurement points of the defective blade.

[0026] In another specific embodiment, in S1, the defective blade is measured to obtain the contour measurement points of the defective blade, specifically including: measuring the defective blade using a scanning method to obtain the contour measurement points of the defective blade.

[0027] like Figure 2 As shown, in S3, the defective areas of the defective blade model are repaired using the defect-free areas of the defective blade model to obtain a repaired defective blade model. Specifically, this includes: S31. Divide the entire defective blade model along the height direction of the defective blade to obtain multiple slice layers; based on the defective area of ​​the defective blade model, determine the defective slice layer from the multiple slice layers, and use the outline of the defective slice layer as the defect cross-sectional curve; use the outline of the non-defective slice layer adjacent to the first defective slice layer located in the preset repair direction as the initial reference curve. S32. Based on the reference curve, repair the cross-sectional curve of the defect adjacent to the reference curve to obtain the repaired cross-sectional curve; S33. Determine whether the repair section curve has adjacent defect cross-sectional curves; If so, proceed to S34; If not, then complete the repair of all defect cross-sectional curves in the defect area; S34. Use the repair section curve as the reference curve and proceed to S32.

[0028] In practice, the outline of the defect-free slice layer adjacent to the defect area in the preset repair direction is used as the initial reference curve. Based on the reference curve, the defect cross-sectional curves adjacent to the reference curve are iteratively repaired until the repair cross-sectional curve does not have adjacent defect cross-sectional curves, so as to improve the repair accuracy.

[0029] In S32, based on the reference curve, the defect cross-sectional curve adjacent to the reference is repaired to obtain the repaired cross-sectional curve, specifically including: S321. The reference curve and the defect cross-section curve adjacent to the reference curve are sampled by the equidistant sampling method. The multiple discrete points of the sampled reference curve are used as the control point set of the reference curve, and the multiple discrete points of the sampled defect cross-section curve are used as the measurement point set of the defect cross-section curve. S322. The control point set of the reference curve and the measurement point set of the defect cross section curve are rigidly registered to obtain the rotation matrix and translation matrix. S323. Perform B-spline curve fitting on the control point set of the reference curve and the defect cross-section curve adjacent to the reference curve to obtain the reference B-spline curve and the defect B-spline curve. S324. Based on the rotation matrix and translation matrix, apply an affine transformation to the defect B-spline curve to map it to the reference B-spline curve, and obtain the aligned defect B-spline curve. S325. Deform the aligned defect B-spline curve so that the shape of the deformed defect B-spline curve and the shape error of the reference B-spline curve meet the preset error, and use the defect B-spline curve that meets the preset error as the repair section curve.

[0030] In the blade height direction, the projection of the defect cross-section curve and the reference curve shows a certain rotation angle. When the reference curve is used to repair the defective cross-section curve, the measurement points of the reference curve and the defective cross-section curve need to be registered. In this embodiment, the measurement points of the defective curve and the reference curve are first registered to obtain a rotation matrix and a translation matrix. Then, based on the rotation matrix and the translation matrix, the reference curve is deformed to recover the defective cross-section curve. This allows for iterative deformation of the reference curves adjacent to the defective cross-section curve to repair the defective area. This embodiment, by iteratively deforming the reference curves adjacent to the defective cross-section curve to repair the defective area, can inherit the characteristics of the adjacent reference curves and limit the deformation of the reference curves to a very small range, thereby avoiding unnecessary bending abrupt changes and effectively avoiding uncertainties in the repair process. In addition, by adapting the contact measurement points, the accuracy of the repaired surface is improved. After establishing the model, laser deposition is used for repair. Furthermore, by adjusting the contact measurement points, the accuracy of the repaired surface is improved to a certain extent.

[0031] In the iterative deformation of the reference curve adjacent to the defective cross-section curve, the first defective cross-section curve is repaired by deforming the reference curve; then, the previously repaired defective cross-section curve is assumed to be the reference curve, and the next defective cross-section curve is repaired; this process is repeated until all defective cross-section curves are completely repaired.

[0032] In S322, the control point set of the reference curve and the measurement point set of the defect cross-section curve are rigidly registered to obtain the rotation matrix and translation matrix, specifically including: S3221. Based on the control point set of the reference curve and the measurement point set of the defect cross section curve, establish the mapping relationship between the control points of the reference curve and the measurement points of the defect cross section curve. S3222. Based on the mapping relationship between the control points of the reference curve and the measurement points of the defect cross-section curve, calculate the offset of the control point set of the reference curve; based on the offset of the control point set of the reference curve and the preset local confidence weight, update the control point set of the reference curve; perform coarse registration between the control point set of the reference curve and the measurement point set of the defect cross-section curve to obtain the initial rotation matrix and translation matrix. S3223. Based on the control point set of the reference curve and the initial rotation and translation matrices, the measurement point set of the intermediate repair section curve is obtained; S3224. Calculate the average distance function between the measurement point set of the intermediate repair section curve and the measurement points of the defect cross section curve; S3225. Determine whether the value of the average distance function is less than the preset average distance function threshold; if so, stop the calculation and obtain the final translation matrix and rotation matrix. If not, proceed to S3226: S3226, Transform the translation and rotation matrices; Update the control point set of the reference curve based on the transformed translation and rotation matrices, and update the reference curve based on the updated control point set of the reference curve, and then proceed to S323.

[0033] In this embodiment, the relationship between the control point set of the reference curve and the measurement points of the defect cross-section curve adjacent to the reference curve is first determined. Then, based on this relationship, coarse registration and fine registration are performed on the control point set of the reference curve and the measurement point set of the defect cross-section curve adjacent to the reference curve, so as to obtain accurate translation and rotation matrices.

[0034] in, In the formula, Represents the average distance function. Let i represent the i-th measurement point in the set of measurement points P1 representing the cross-section of the defect. Let i represent the i-th measurement point in the measurement point set P2 of the intermediate repair section curve, where i = 1, 2, ..., N, and N represents the total number of measurement points.

[0035] in, In the formula, R represents the control point set of the updated reference curve, T represents the translation matrix, and Q represents the control point set of the reference curve.

[0036] In this embodiment, the set of measurement points for the defect cross-section curve is set as P1 = {p1 i} (i = 1, ..., N); the reference curve is assumed to be Γ, and the set of control points for Γ is assumed to be Q = {qi} (i = 1, ..., N); The measurement point set P2 of the intermediate repair section curve is p2 = {p2i}, i = 1, ..., N.

[0037] Specifically, based on the control point set of the reference curve and the measurement point set of the defect cross-section curve, a mapping relationship between the control points of the reference curve and the measurement points of the defect cross-section curve is established, including: The measurement point set of the defect cross-section curve is preprocessed and uniformly parameterized to obtain the parameter sequence of the defect cross-section curve. Based on the node vector of the reference curve, the parameter sequence of the defect cross section curve is aligned by node mapping. Construct a configuration matrix based on the node vector of the reference curve; Using a B-spline-based cross-sectional curve interpolation algorithm, the measurement point set of the aligned defect cross-section curve is fitted with the nodal vector of the reference curve using least squares, resulting in virtual control points that correspond one-to-one with the control points of the defect cross-section curve and the reference curve. Based on the virtual control points where the control points of the defect cross-section curve and the reference curve correspond one by one, establish a one-to-one mapping relationship between the control points of the reference curve and the measurement points of the defect cross-section curve.

[0038] Specifically, set the control point set of the reference curve. The control point set includes n + 1 control points, and the expression of each control point is d i , i = 0, …, n; the knot vector of the control points is set to U = [u0, u1, …, u n + k + 1 , k is the degree.

[0039] To make the measurement points at both ends of the defect cross-section curve consistent with the first and last control points of the reference curve, that is, u0 = … = u k = 0, u n + 1 = … = u n + k + 1 = 1; set the measurement point set of the defect cross-section curve. The measurement point set has m measurement points, and each measurement point is qi, i = 1, …, m.

[0040] During interpolation calculation, q1, q2, …, qm respectively correspond to u k , u k+1 , …, u n + 1 , where n = m + k - 2. Then the expression of the B-spline curve is ; in the formula, represents the B-spline curve, represents the basic function of the B-spline curve.

[0041] During the process of determining the standard of the measurement point density, q i and q i + 1 are point constraints, p i and p i + 1 are the closest points of q i and q i + 1 on the reference curve. When the q i constraint is executed, the change of the entire reference curve caused by the movement of p i should include the part between p i and p i + 1 , corresponding to the defect part q i ~q i + 1 . Therefore, this embodiment determines the relationship between the density of the measurement points in the defect cross-section curve and the size of the defect area.

[0042] Among them, based on the control point set set of the reference curve and the initial rotation matrix and translation matrix, obtain the measurement point set of the intermediate repair section curve, specifically including: Use the initial translation matrix and rotation matrix to transform the measurement point set of the defect cross-section curve into the coordinate system of the reference curve to complete the rough alignment; Using a cross-sectional curve interpolation algorithm based on B-splines, the measurement point set of the coarsely aligned defect cross-section curve is fitted with the nodal vector of the reference curve using least squares, resulting in virtual control points that correspond one-to-one with the control points of the defect cross-section curve and the reference curve. Using the defect in the cross-section curve as the deformation driving force, the measurement points of the cross-section curve are reconstructed by weighting based on the virtual control points of the cross-section curve, resulting in the intermediate repair section curve and the set of measurement points of the intermediate repair section curve.

[0043] In S3222, the control point set of the reference curve and the measurement point set of the defect cross-section curve are coarsely registered to obtain the initial rotation and translation matrices, specifically including: Discretize the reference curve Γ and the defect cross section curve Γ′ respectively, and calculate the first centroid G of the discretized Γ relative to the discrete point and the second centroid G′ of the discretized Γ′ relative to the discrete point respectively. Establish the translation matrix T between the first centroid G and the second centroid G′; Directional features are extracted from Γ and Γ′ respectively; the directional features include: the center point of the inner arc (O1, O1′), the center point of the exit arc (O2, O2′), and the chord length ( ) and maximum blade thickness ( ); Based on the directional features of Γ and Γ′, establish the directional relationship between the directional features of Γ and Γ′; Based on the directional relationship between Γ and Γ′, a rotation matrix R between Γ and Γ′ is established with the centroids G and G′ as the origins, respectively.

[0044] In S325, the aligned defect B-spline curve is deformed so that the shape error between the deformed defect B-spline curve and the reference B-spline curve meets a preset error, specifically including: When the defect of the aligned defect B-spline curve meets the preset small defect conditions, the control points corresponding to the defect area of ​​the defect B-spline curve are locally replaced by the control points of the reference B-spline curve. If the defect of the aligned defect B-spline curve meets the preset large defect condition or complex defect condition, a smooth deformation field is constructed between the reference B-spline curve and the aligned defect B-spline curve, and a weighting function is introduced to control the deformation intensity of the aligned defect B-spline curve, and the control points of the defect B-spline curve are updated so that the shape error between the deformed defect B-spline curve and the shape error of the reference B-spline curve meets the preset error.

[0045] In this embodiment, based on the defective blade repair model, laser is used to adaptively process the defective blade to obtain the repaired blade, specifically including: Based on the defective blade model, laser deposition is used to adaptively process the defective blade to obtain the repaired blade.

[0046] In the adaptive processing of defective blades using laser deposition, the defective area of ​​the blade is first remelted and heated multiple times using a laser, and then powder is deposited on the remelted and heated defective area using a laser. After the deposition is completed, the defective area after powder deposition is scanned by a laser at preset time intervals within a preset time period.

[0047] Specifically, in the adaptive processing of defective blades using laser deposition, a 5000W laser is first used to remelt and heat the defective area of ​​the defective blade multiple times. After the blade temperature reaches 400℃ and impurities are dissolved, a 2000W laser is used to deposit powder on the remelted and heated defect area. After deposition, a 2500W laser scan is performed every 5 minutes for a total of 10 scans. This reduces residual stress and prevents cracking at the repair site.

[0048] Secondly, this invention also proposes an adaptive laser deposition repair system for defective turbine blades, comprising: The measurement module is used to measure the defective blade and obtain the contour measurement points of the defective blade; The reconstruction module is used to reconstruct the surface based on the contour measurement points of the defective blade to obtain the defective blade model; The model repair module is used to repair the defective areas of the defective blade model using the defect-free areas of the defective blade model, so as to obtain a repaired defective blade model. The laser module is used to adaptively process the defective blades using lasers based on the defective blade repair model, so as to obtain the repaired blades.

[0049] Specifically, the defective areas of the defective blade model are repaired using the defect-free areas of the defective blade model to obtain a repaired defective blade model. This process includes: The entire defective blade model is divided along the height direction of the defective blade to obtain multiple slice layers. Based on the defective area of ​​the defective blade model, the defective slice layer is determined from the multiple slice layers, and the outline of the defective slice layer is used as the defect cross-section curve. The outline of the non-defective slice layer adjacent to the first defective slice layer located in the preset repair direction is used as the initial reference curve. Based on the reference curve, the defect cross-sectional curves adjacent to the reference curve are repaired to obtain the repaired cross-sectional curve; it is determined whether the repaired cross-sectional curve has an adjacent defect cross-sectional curve; if not, the repair of all defect cross-sectional curves in the defect area is completed; if so, the repaired cross-sectional curve is used as the reference curve, and registration and repair are performed again until the repair of all defect cross-sectional curves in the defect area is completed.

[0050] Specifically, based on the reference curve, the defect cross-sectional curve adjacent to the reference curve is repaired to obtain the repaired cross-sectional curve, which includes: The equidistant sampling method is used to sample the reference curve and the defect cross-section curve adjacent to the reference curve. The multiple discrete points of the sampled reference curve are used as the control point set of the reference curve, and the multiple discrete points of the sampled defect cross-section curve are used as the measurement point set of the defect cross-section curve. The rotation matrix and translation matrix are obtained by rigidly registering the control point set of the reference curve and the measurement point set of the defect cross section curve. B-spline curves are fitted to the control point set of the reference curve and the defect cross-section curve adjacent to the reference curve to obtain the reference B-spline curve and the defect B-spline curve. Based on the rotation and translation matrices, an affine transformation is applied to the defect B-spline curve to map it to the reference B-spline curve, resulting in the aligned defect B-spline curve. The aligned defect B-spline curve is deformed so that the shape of the deformed defect B-spline curve and the shape error of the reference B-spline curve meet the preset error, and the defect B-spline curve that meets the preset error is used as the repair section curve.

[0051] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An adaptive laser deposition repair method for defective turbine blades, characterized in that, include: S1. Measure the defective blade to obtain the contour measurement points of the defective blade; S2. Based on the contour measurement points of the defective blade, surface reconstruction is performed to obtain the defective blade model; S3. Use the defect-free area of ​​the defective blade model to repair the defective area of ​​the defective blade model to obtain the repaired defective blade model. S4. Based on the defective blade model, the defective blade is adaptively processed using laser to obtain the repaired blade.

2. The adaptive laser deposition repair method for defective turbine blades according to claim 1, characterized in that, In S3, the defective areas of the defective blade model are repaired using the defect-free areas of the defective blade model, resulting in a repaired defective blade model. Specifically, this includes: S31. Divide the entire defective blade model along the height direction of the defective blade to obtain multiple slice layers; based on the defective area of ​​the defective blade model, determine the defective slice layer from the multiple slice layers, and use the outline of the defective slice layer as the defect cross-section curve; use the outline of the defect-free slice layer adjacent to the first defective slice layer located in the preset repair direction as the initial reference curve. S32. Based on the reference curve, repair the cross-sectional curve of the defect adjacent to the reference curve to obtain the repaired cross-sectional curve; S33. Determine whether the repair section curve has adjacent defect cross-sectional curves; If so, proceed to S34; If not, then the process ends; S34. Use the repair section curve as the reference curve and proceed to S32.

3. The adaptive laser deposition repair method for defective turbine blades according to claim 2, characterized in that, In S32, based on the reference curve, the defect cross-sectional curve adjacent to the reference curve is repaired to obtain the repaired cross-sectional curve, specifically including: S321. The reference curve and the defect cross-section curve adjacent to the reference curve are sampled by the equidistant sampling method. The multiple discrete points of the sampled reference curve are used as the control point set of the reference curve, and the multiple discrete points of the sampled defect cross-section curve are used as the measurement point set of the defect cross-section curve. S322. The control point set of the reference curve and the measurement point set of the defect cross section curve are rigidly registered to obtain the rotation matrix and translation matrix. S323. Perform B-spline curve fitting on the control point set of the reference curve and the defect cross-section curve adjacent to the reference curve to obtain the reference B-spline curve and the defect B-spline curve. S324. Based on the rotation matrix and translation matrix, apply an affine transformation to the defect B-spline curve to map it to the reference B-spline curve, and obtain the aligned defect B-spline curve. S325. Deform the aligned defect B-spline curve so that the shape error between the deformed defect B-spline curve and the reference B-spline curve meets the preset error, and use the defect B-spline curve that meets the preset error as the repair section curve.

4. The adaptive laser deposition repair method for defective turbine blades according to claim 3, characterized in that, In S325, the aligned defect B-spline curve is deformed so that the shape error between the deformed defect B-spline curve and the reference B-spline curve meets a preset error, specifically including: When the defect of the aligned defect B-spline curve meets the preset small defect conditions, the control points corresponding to the defect area of ​​the defect B-spline curve are locally replaced by the control points of the reference B-spline curve. If the defect of the aligned defect B-spline curve meets the preset large defect condition or complex defect condition, a smooth deformation field is constructed between the reference B-spline curve and the aligned defect B-spline curve, and a weighting function is introduced to control the deformation intensity of the aligned defect B-spline curve, and the control points of the defect B-spline curve are updated so that the shape error between the deformed defect B-spline curve and the shape error of the reference B-spline curve meets the preset error.

5. The adaptive laser deposition repair method for defective turbine blades according to claim 3, characterized in that, In S322, the control point set of the reference curve and the measurement point set of the defect cross-section curve are rigidly registered to obtain the rotation matrix and translation matrix, specifically including: S3221. Based on the control point set of the reference curve and the measurement point set of the defect cross section curve, establish the mapping relationship between the control points of the reference curve and the measurement points of the defect cross section curve. S3222. Based on the mapping relationship between the control points of the reference curve and the measurement points of the defect cross-section curve, calculate the offset of the control point set of the reference curve; based on the offset of the control point set of the reference curve and the preset local confidence weight, update the control point set of the reference curve; perform coarse registration between the control point set of the reference curve and the measurement point set of the defect cross-section curve to obtain the initial rotation matrix and translation matrix. S3223. Based on the control point set of the reference curve and the initial rotation and translation matrices, the measurement point set of the intermediate repair section curve is obtained; S3224. Calculate the average distance function between the measurement point set of the intermediate repair section curve and the measurement points of the defect cross section curve; S3225. Determine whether the value of the average distance function is less than the preset average distance function threshold; if so, stop the calculation and obtain the final translation matrix and rotation matrix. If not, proceed to S3226: S3226. Transform the translation and rotation matrices; update the control point set of the reference curve based on the transformed translation and rotation matrices, and update the reference curve based on the updated control point set of the reference curve, and then proceed to S3223.

6. The adaptive laser deposition repair method for defective turbine blades according to claim 5, characterized in that, Based on the control point set of the reference curve and the measurement point set of the defect cross-section curve, a mapping relationship between the control points of the reference curve and the measurement points of the defect cross-section curve is established, specifically including: The measurement point set of the defect cross-section curve is preprocessed and uniformly parameterized to obtain the parameter sequence of the defect cross-section curve. Based on the node vector of the reference curve, the parameter sequence of the defect cross section curve is aligned by node mapping. Construct a configuration matrix based on the node vector of the reference curve; Using a B-spline-based cross-sectional curve interpolation algorithm, the measurement point set of the aligned defect cross-section curve is fitted with the nodal vector of the reference curve using least squares, resulting in virtual control points that correspond one-to-one with the control points of the defect cross-section curve and the reference curve. Based on virtual control points that correspond one-to-one with the control points of the defect cross-section curve and the reference curve, a one-to-one mapping relationship is established between the control points of the reference curve and the measurement points of the defect cross-section curve.

7. The adaptive laser deposition repair method for defective turbine blades according to claim 5, characterized in that, Based on the control point set of the reference curve and the initial rotation and translation matrices, the measurement point set of the intermediate repair section curve is obtained, specifically including: Using the initial translation and rotation matrices, the measurement point set of the defect cross section curve is transformed to the coordinate system of the reference curve to complete the coarse alignment; Using a B-spline-based cross-sectional curve interpolation algorithm, the measurement point set of the coarsely aligned defect cross-section curve is fitted with the nodal vector of the reference curve using least squares, resulting in virtual control points that correspond one-to-one with the control points of the defect cross-section curve and the reference curve. Using the defect in the cross-section curve as the deformation driving quantity, the measurement points of the cross-section curve are reconstructed by weighting according to the virtual control points of the cross-section curve, so as to obtain the intermediate repair section curve and the measurement point set of the intermediate repair section curve.

8. The adaptive laser deposition repair method for defective turbine blades according to claim 3, characterized in that, In S3222, the control point set of the reference curve and the measurement point set of the defect cross-section curve are coarsely registered to obtain the initial rotation matrix and translation matrix, specifically including: Discretize the reference curve and the defect cross-section curve, and calculate the first centroid of the discretized reference curve relative to the discrete point and the second centroid of the discretized defect cross-section curve relative to the discrete point, and establish the translation matrix between the first centroid and the second centroid. Directional features were extracted from the reference curve and the defect cross-section curve, respectively; the directional features included: the center point of the inner arc, the center point of the exit arc, the chord length, and the maximum thickness of the blade. Based on the directional characteristics of the reference curve and the defect cross-section curve, establish the directional relationship between the directional characteristics of the reference curve and the defect cross-section curve; Based on the directional relationship between the reference curve and the defect cross-section curve, a rotation matrix between the reference curve and the defect cross-section curve is established with the first centroid and the second centroid as the origin, respectively.

9. The adaptive laser deposition repair method for defective turbine blades according to claim 1, characterized in that, Based on the defective blade model, laser adaptive processing is used to process the defective blade to obtain the repaired blade, specifically including: Based on the defective blade model, laser deposition was used to adaptively process the defective blade to obtain the repaired blade. Preferably, in the adaptive processing of defective blades using laser deposition, the defective area of ​​the defective blade is first remelted and heated multiple times using a laser, and then powder is deposited on the remelted and heated defective area using a laser. After the deposition is completed, the defective area after powder deposition is scanned by a laser at preset time intervals within a preset time period.

10. An adaptive laser deposition repair system for defective turbine blades, characterized in that, include: The measurement module is used to measure the defective blade and obtain the contour measurement points of the defective blade. The reconstruction module is used to reconstruct the surface based on the contour measurement points of the defective blade to obtain the defective blade model; The model repair module is used to repair the defective areas of the defective blade model using the defect-free areas of the defective blade model, so as to obtain a repaired defective blade model. The laser module is used to adaptively process the defective blades using lasers based on the defective blade repair model, so as to obtain the repaired blades.

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