Adaptive positioning method for turbine blade tip electrospark forming

Abstract

The present application relates to the field of aero-engine manufacturing and maintenance technology, and specifically discloses an adaptive positioning method for the electric spark forming of the blade tip of a turbine blade, including setting an adaptive positioning device used; the method includes placing a standard plate under a profiling electrode set on an arc generator, using the profiling electrode to perform discharge machining on the plate, and recording the first coordinate of the standard plate at this time; moving the machining contour machined by the profiling electrode on the standard plate to the center of the field of view of a paraxial camera, extracting the machining contour, and recording the second coordinate of the standard plate at this time; moving the blade to the center of the field of view of the paraxial camera, extracting the outer contour of the blade tip, making the distance between the machining contour and the outer contour of the blade tip meet the preset requirements, and recording the third coordinate of the blade at this time; and obtaining the machining coordinates of the electric spark forming of the blade tip. This changes the previous mode of positioning by manual visual observation, alleviates labor intensity, shortens operation time, and improves positioning accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of aero-engine manufacturing and maintenance, and in particular to an adaptive positioning method for electric spark forming of turbine blade tips. Background Art

[0002] The blade tip of a certain type of aircraft engine high-pressure turbine blade is subjected to thermal corrosion and thermal stress of high temperature and high pressure during operation, and the blade tip is prone to cracks and falling pieces. During repair, the blade tip fault part is removed by polishing and welding, and the whole blade tip is extended. After the extension, the blade tip welding material is hard and the inner cavity is narrow, so it is impossible to use a machining center or grinding to restore the inner cavity surface. Therefore, it is necessary to use electric spark forming to restore the inner cavity of the blade tip.

[0003] The blade tip inner cavity weld nodules are processed by designing a contour electrode for the blade tip inner cavity. The processing requirements ensure that the wall thickness of the blade basin and blade back meets the drawings. During processing, the relative position of the electrode and the blade is adjusted by manual visual observation. The contours of the electrode and the blade tip are complex and distorted and are affected by factors such as electrode shielding. Manual observation from the side shows large tool positioning errors and low stability, resulting in the blade wall thickness not meeting the requirements and a high processing failure rate, which leads to product rework or even scrapping. Summary of the invention

[0004] The purpose of the present application is to provide an adaptive positioning method for the electrospark forming of turbine blade tips, so as to solve the problem that in the prior art, when machining the inner cavity weld nodule of the blade tip by designing a contoured electrode for the inner cavity of the blade tip, the tool positioning error is large and the stability is low when manually observing from the side, resulting in the blade wall thickness not meeting the requirements and a high processing failure rate, which leads to rework or even scrapping of the product.

[0005] To achieve the above-mentioned purpose, the present application provides an adaptive positioning method for turbine blade tip electrospark forming.

[0006] The method comprises setting an adaptive positioning device used,

[0007] The device comprises: an arc generator and a paraxial camera arranged on a main shaft of a machine tool;

[0008] The adaptive positioning method using the device includes:

[0009] Placing a standard plate under a contour electrode provided on the arc generator, performing electrical discharge machining on the plate using the contour electrode, and recording a first coordinate of the standard plate at this time;

[0010] After the discharge machining is completed, the machining contour formed by the profiling electrode on the standard flat plate is moved to the center of the field of view of the rangefinder camera, the first image acquired by the rangefinder camera is recognized, the machining contour is extracted, and the second coordinate of the standard flat plate and the standard Z-axis distance between the rangefinder camera and the standard flat plate are recorded;

[0011] The blade is moved to the center of the field of view of the paraxial camera, the distance between the paraxial camera and the blade tip is adjusted to the standard Z-axis distance, the second image acquired by the paraxial camera is recognized, the outer contour of the blade tip is extracted, the distance between the processed contour and the outer contour of the blade tip meets the preset requirements, and the third coordinate of the blade at this time is recorded;

[0012] Based on the first coordinate, the second coordinate and the third coordinate, the machining coordinates of the blade tip electrospark forming are obtained.

[0013] Optionally, the identifying the first image acquired by the rangefinder camera to extract the processing contour specifically includes:

[0014] Preprocessing the first image, wherein the preprocessing includes grayscale, contrast enhancement and binarization processing;

[0015] On the preprocessed first image, obtaining boundary pixel points in the first image by using an edge detection algorithm;

[0016] Through connectivity analysis, adjacent boundary pixel points are connected to obtain the processing contour.

[0017] Optionally, the identifying the second image acquired by the paraxial camera to extract the outer contour of the blade tip specifically includes:

[0018] Preprocessing the second image, wherein the preprocessing includes grayscale, contrast enhancement and binarization processing;

[0019] On the preprocessed second image, obtaining boundary pixel points in the second image by using an edge detection algorithm;

[0020] Through connectivity analysis, the adjacent boundary pixel points are connected to obtain the outer contour of the leaf tip.

[0021] Optionally, making the distance between the machining contour and the outer contour of the blade tip meet a preset requirement specifically includes:

[0022] Obtaining a minimum value of the distance between the machining contour and the outer contour of the blade tip through an image processing algorithm, and judging whether the minimum value is greater than a preset value, if so, the distance between the machining contour and the outer contour of the blade tip meets the preset requirement;

[0023] If not, the blade is controlled to move in the X-axis and Y-axis directions of the machine tool and to rotate in the C-axis direction to adjust the position until the minimum value is greater than the preset value.

[0024] Optionally, the obtaining the minimum value of the distance between the machining contour and the outer contour of the blade tip by using an image processing algorithm specifically includes:

[0025] On the second image, a ruler with a known unit length is set, and the number of pixel points within the unit length is constant;

[0026] By comparing the ruler, the number of pixels between the machining contour and the outer contour of the blade tip is calculated;

[0027] According to the corresponding relationship between the unit length of the ruler and the number of pixels, the number of pixels between the machining contour and the outer contour of the blade tip is converted into a distance;

[0028] The minimum value of the distance is found by a traversal or search algorithm.

[0029] Optionally, after the blade is moved to the center of the field of view of the paraxial camera, the method further comprises:

[0030] A paraxial camera is used to obtain the height difference between the blade tip surface and the cover plate set in the blade.

[0031] Optionally, obtaining machining coordinates of blade tip electrospark forming based on the first coordinate, the second coordinate and the third coordinate specifically includes:

[0032] Using the formula:

[0033] X 4 =X 3 +( X 1 -X 2 ),

[0034] Y 4 = Y 3 +( Y 1 -Y 2 ),

[0035] Get the processing coordinates, where X 4 is the X-axis coordinate of the processing coordinate, Y 4 is the Y-axis coordinate of the processing coordinate, X 1 is the X-axis coordinate of the first coordinate, Y 1 is the Y-axis coordinate of the first coordinate, X 2 is the X-axis coordinate of the second coordinate, Y 2 is the Y-axis coordinate of the second coordinate, X 3 is the X-axis coordinate of the third coordinate, Y 3 is the Y-axis coordinate including the third coordinate.

[0036] Optionally, the process of performing electrical discharge machining on the flat plate using the profiling electrode specifically includes:

[0037] The machining depth of the electrical discharge machining is 1 mm to 2 mm greater than the chamfer radius of the electrode.

[0038] The embodiments of the present application have the following advantages:

[0039] Compared with the existing technology, the adaptive positioning method provided by the above technical solution can determine the optimal relative position of the electrode and the blade by using the identified processing contour and the outer contour of the blade tip through the cooperation of the paraxial camera and the arc generator set on the main shaft of the machine tool, which changes the previous mode of positioning by manual visual observation, alleviates labor intensity, shortens operation time, improves positioning accuracy, ensures that the wall thickness value meets the requirements and is uniform, improves the qualified rate of electrospark forming processing of the blade tip of the high-pressure turbine working blade, and meets the needs of rapid delivery of equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0041] Figure 1 A schematic diagram of an adaptive positioning device provided for an adaptive positioning method for electrospark forming of a turbine blade tip provided by at least one embodiment of the present application;

[0042] Figure 2 A schematic diagram of an extraction machining contour of an adaptive positioning method for electrospark forming of a turbine blade tip provided by at least one embodiment of the present application;

[0043] Figure 3 A schematic diagram of adjusting the distance between a machining contour and a blade tip outer contour of an adaptive positioning method for electrospark forming of a turbine blade tip provided by at least one embodiment of the present application;

[0044] Figure 4 A schematic diagram of a blade tip surface and a cover plate structure provided for at least one embodiment of the present application;

[0045] Figure 5 A diagram showing the effect of a turbine blade tip after electrospark forming processing according to an adaptive positioning method for electrospark forming of a turbine blade tip provided in at least one embodiment of the present application.

[0046] Meaning of the reference symbols:

[0047] 1. Arc generator, 2. Rangefinder camera, 3. Machine tool spindle, 4. Blade tip surface, 5. Cover plate. DETAILED DESCRIPTION

[0048] The following is a description of the implementation of the present application by specific specific embodiments. People familiar with the technology can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0049] In the description of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Unless otherwise clearly specified and limited, the terms "set", "install", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0050] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0051] The present application embodiment provides an adaptive positioning method for turbine blade tip electrospark forming, referring to Figures 1 to 5 , including the adaptive positioning device used in setting, refer to Figure 1 The device comprises: an arc generator 1 and a paraxial camera 2 arranged on a machine tool spindle 3.

[0052] The adaptive positioning method using the device includes:

[0053] S101, standard sample processing: place a 0.5mm-1mm standard flat plate under the profiling electrode set on the arc generator 1, and use the profiling electrode to perform electrical discharge processing on the flat plate. In some embodiments, the processing depth of the electrical discharge processing is greater than the chamfer radius of the electrode by about 1mm-2mm. Record the first coordinate of the standard flat plate at this time, including the first X-axis coordinate and the first Y-axis coordinate: X 1 ,Y 1 The contoured electrode is a contoured electrode designed to imitate the shape of the inner cavity of the blade tip.

[0054] S102, extracting the machining contour: After the discharge machining is completed, the electrode is lifted, and the machining contour machined by the profiling electrode on the standard flat plate is moved to the center of the field of view of the rangefinder camera 2, and the Z axis of the rangefinder camera 2 (the Z axis represents the height of the rangefinder camera 2 relative to the workpiece) is adjusted to make the image clear. The rangefinder camera 2 transmits the captured image to the computer. In some embodiments, the first image obtained by the rangefinder camera 2 is recognized by image recognition technology, and the machining contour is extracted and displayed in real time on the interface (such as Figure 2 ). And record the second coordinates of the standard plate at this time, including the second X-axis coordinate and the second Y-axis coordinate: X 2 ,Y 2 , and the standard Z-axis distance between the rangefinder camera 2 and the standard plate: △Z.

[0055] In some embodiments, the identifying the first image acquired by the rangefinder camera 2 and extracting the processing contour specifically includes:

[0056] Preprocessing the first image, wherein the preprocessing includes grayscale, contrast enhancement and binarization processing;

[0057] On the preprocessed first image, edge detection algorithms (such as Canny, Sobel, etc.) are used to obtain boundary pixel points in the first image;

[0058] Through connectivity analysis, adjacent boundary pixel points are connected to obtain the processing contour.

[0059] Specifically, the grayscale processing includes converting the acquired color image into a grayscale image. Grayscale images only contain brightness information, not color information, which helps to simplify subsequent processing steps. Contrast enhancement processing includes enhancing the contrast between different objects in the image by adjusting the grayscale value of the image to make the contour clearer. Binarization processing includes converting the grayscale image into a binary image, that is, the grayscale value of each pixel on the image is set to 0 or 255, representing black and white, respectively. This step helps to remove noise from the image and highlight the target contour. After the complete processing contour is extracted, it can be further processed (such as denoising, smoothing, etc.) to ensure the accuracy and completeness of the contour.

[0060] S103, adaptive positioning: The blade is clamped with a special tool and moved to the center of the field of view of the paraxial camera 2. The distance between the paraxial camera 2 and the blade tip is adjusted to the standard Z-axis distance △Z. The real-time image captured by the paraxial camera 2 is transmitted to the computer. In some embodiments, the second image obtained by the paraxial camera 2 is recognized by image recognition technology, and the outer contour of the blade tip is extracted and displayed in real time. The distance between the processing contour and the outer contour of the blade tip meets the preset requirements, and the third coordinate of the blade at this time is recorded, including the third X-axis coordinate and the third Y-axis coordinate: X 3 ,Y 3 .

[0061] In some embodiments, the identifying the second image acquired by the paraxial camera 2 and extracting the outer contour of the blade tip specifically includes:

[0062] Preprocessing the second image, wherein the preprocessing includes grayscale, contrast enhancement and binarization processing;

[0063] On the preprocessed second image, edge detection algorithms (such as Canny, Sobel, etc.) are used to obtain boundary pixel points in the second image;

[0064] Through connectivity analysis, the adjacent boundary pixel points are connected to obtain the outer contour of the leaf tip.

[0065] The specific extraction method refers to the above-mentioned embodiment of extracting the processing contour, which will not be described in detail here.

[0066] In some embodiments, making the distance between the machining contour and the outer contour of the blade tip meet a preset requirement specifically includes:

[0067] Obtaining a minimum value of the distance between the machining contour and the outer contour of the blade tip through an image processing algorithm, and judging whether the minimum value is greater than a preset value, if so, the distance between the machining contour and the outer contour of the blade tip meets the preset requirement;

[0068] If not, the program algorithm calls the X, Y, and C axis instructions of the CNC EDM forming machine to control the blade to move in the X and Y axis directions and rotate in the C axis direction of the machine to adjust the position. After the position adjustment is completed, the minimum value of the distance between the machining contour and the outer contour of the blade tip is automatically obtained, and the judgment is made again until the minimum value is greater than the preset value.

[0069] Specifically, the distance between the machining contour and the outer contour of the blade tip, i.e., the wall thickness value (e.g. Figure 3 , the black line segment in the figure is the wall thickness scale).

[0070] In some embodiments, the obtaining the minimum value of the distance between the machining contour and the outer contour of the blade tip by using an image processing algorithm specifically includes:

[0071] On the second image, a ruler with a known unit length is set, and the number of pixel points within the unit length is constant;

[0072] By comparing the ruler, the number of pixels between the machining contour and the outer contour of the blade tip is calculated;

[0073] According to the corresponding relationship between the unit length of the ruler and the number of pixels, the number of pixels between the machining contour and the outer contour of the blade tip is converted into a distance;

[0074] The minimum value of the distance is found by a traversal or search algorithm.

[0075] In some embodiments, after moving the blade to the center of the field of view of the paraxial camera 2, the method further includes:

[0076] The infrared rangefinder of the paraxial camera 2 is used to obtain the height difference ΔH (such as Figure 4 ), the depth for subsequent forming processing can be obtained.

[0077] S104, blade discharge machining: After the relative position of the blade tip outer contour and the machining contour is fixed, the machining coordinates of the blade tip electrospark forming are obtained based on the first coordinate, the second coordinate and the third coordinate. Then, the machine tool is controlled by a computer program algorithm to move the blade to the machining coordinates of the blade tip electrospark forming, and the machining depth is automatically set to the height difference △H between the blade tip surface 4 and the cover plate 5 set in the blade, and then the blade tip electrospark forming machining can be started.

[0078] In some embodiments, obtaining the machining coordinates of the blade tip electrospark forming based on the first coordinate, the second coordinate and the third coordinate specifically includes:

[0079] Using the formula:

[0080] X 4 =X 3 +( X 1 -X 2 ),

[0081] Y 4 = Y 3 +( Y 1 -Y 2 ),

[0082] Get the processing coordinates, where X 4 is the X-axis coordinate of the processing coordinate, Y 4 is the Y-axis coordinate of the processing coordinate, X1 is the X-axis coordinate of the first coordinate, Y 1 is the Y-axis coordinate of the first coordinate, X 2 is the X-axis coordinate of the second coordinate, Y 2 is the Y-axis coordinate of the second coordinate, X 3 is the X-axis coordinate of the third coordinate, Y 3 is the Y-axis coordinate including the third coordinate.

[0083] In summary, the prior art can only manually observe the relative position of the electrode and the blade from the side, and cannot intuitively display the relative position of the electrode and the blade; through the scheme of this application, the image recognition technology can be used to extract the electrode processing contour and the outer contour of the blade tip, and the paraxial camera 2 can intuitively display the processing contour and the relative position of the blade, so as to obtain a higher positioning accuracy and greatly improve the pass rate of the blade EDM forming processing. Through the scheme of this application, the image processing algorithm is combined with the CNC machine tool, and the relative position of the blade and the electrode can be automatically adjusted, the tool setting can be completed, and the processing depth can be automatically measured, so that the blade positioning and processing process do not require manual intervention, and adaptive processing is realized, which reduces the labor intensity of personnel and saves human resources.

[0084] The following examples illustrate the solutions provided by this application through specific examples:

[0085] S201, standard sample processing: place a 0.5mm standard flat plate directly under the electrode, the electrode chamfer radius is 2mm, the lower electrode performs contact sensing on the upper surface of the standard flat plate, and the Z axis is set to zero at the contact sensing stop position, that is, Z 1 =0, the machining depth is set to 3mm, and then discharge machining is performed. The X-axis and Y-axis coordinates of the standard plate are set to zero, that is, X 1 =0,Y 1 =0.

[0086] S202, extracting the machining contour: after the machining is completed, lift the electrode to a Z-axis coordinate of 45 mm to ensure that there is no interference with the electrode when the standard plate is moved, move the machining contour of the electrode on the standard plate to the center of the field of view of the rangefinder camera 2, and adjust the Z axis to make the image clear, move the X-axis coordinate, Y-axis coordinate and Z-axis coordinate to integers within the adjustable range, and the rangefinder camera 2 transmits the captured image to the computer, recognizes the image captured by the camera through image recognition technology, extracts the machining contour and saves it, and records the X-axis and Y-axis coordinates of the standard plate at this time: X 2 =-225,Y 2 =20, and the Z axis coordinate at this time: Z 2 =-5.

[0087] S203, adaptive positioning: The blade is clamped with a special tool and moved to the center of the field of view of the paraxial camera 2. The lower electrode performs contact sensing on the upper surface of the blade tip. The Z axis is set to zero at the contact sensing stop position, that is, Z 3 =0, then move the blade to below the rangefinder camera 2 and adjust the Z axis coordinate to Z 4 =-5. The real-time image captured by the rangefinder camera 2 is transmitted to the computer, and the image recognition technology is used to identify the image, extract the outer contour of the blade tip in real time, and judge the relative position relationship between the processing contour and the outer contour of the blade tip through the image processing algorithm. The program algorithm calls the X, Y, and C axis instructions of the EDM forming machine to control the movement of the blade in the X and Y axis directions and the rotation in the C axis direction. After the position adjustment is completed, the distance (wall thickness value) between the processing contour and the outer contour of the blade tip is automatically calculated. The wall thickness value of the blade basin is 1.05mm, and the wall thickness value of the blade back is 0.82mm. The X-axis and Y-axis coordinates of the blade at this time are set to zero: that is, X 3 =0,Y 3 = 0. Then, the infrared rangefinder of the paraxial camera 2 is used to measure the height difference between the blade tip surface 4 and the cover plate 5, which is 4.2 mm.

[0088] S204, blade discharge machining: computer program algorithm controls the machine tool to move the blade to X 4 = 225, Y 4 = -20, this coordinate is the blade EDM machining coordinate, automatically set the machining depth to 4.2mm, start machining, and the machining is completed. Figure 5 .

[0089] Note that, unless otherwise directly stated, all features disclosed in this specification (including any attached claims, abstracts and drawings) may be replaced by alternative features for achieving the same, equivalent or similar purposes. Therefore, unless otherwise explicitly stated, each feature disclosed is only an example of a group of equivalent or similar features. Where used, further, preferably, further and more preferably are simple beginnings for elaborating another embodiment based on the aforementioned embodiment, and the content of further, preferably, further or more preferably followed by the aforementioned embodiment is combined with the complete composition of another embodiment. Several further, preferably, further or more preferably settings following the same embodiment can be arbitrarily combined to form another embodiment.

[0090] In the implementation of functions and steps, the corresponding functions and steps in various embodiments may also occur in a different order than shown. For example, two consecutive functions and steps may actually be performed or implemented substantially in parallel, and they may sometimes be performed or implemented in the opposite order, depending on the functions involved.

[0091] Although the present application has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made to the present application. Therefore, these modifications or improvements made without departing from the spirit of the present application all fall within the scope of protection claimed in the present application.

Claims

1. An adaptive positioning method for turbine blade tip electrospark forming, characterized in that: The method comprises setting an adaptive positioning device used, The device comprises: an arc generator and a paraxial camera arranged on a main shaft of a machine tool; The adaptive positioning method using the device includes: Placing a standard plate under a contour electrode provided on the arc generator, performing electrical discharge machining on the plate using the contour electrode, and recording a first coordinate of the standard plate at this time; After the discharge machining is completed, the machining contour formed by the profiling electrode on the standard flat plate is moved to the center of the field of view of the rangefinder camera, the first image acquired by the rangefinder camera is recognized, the machining contour is extracted, and the second coordinate of the standard flat plate and the standard Z-axis distance between the rangefinder camera and the standard flat plate are recorded; The blade is moved to the center of the field of view of the paraxial camera, the distance between the paraxial camera and the blade tip is adjusted to the standard Z-axis distance, the second image acquired by the paraxial camera is recognized, the outer contour of the blade tip is extracted, the distance between the processed contour and the outer contour of the blade tip meets the preset requirements, and the third coordinate of the blade at this time is recorded; The step of making the distance between the machining contour and the blade tip outer contour meet the preset requirements specifically includes: The minimum value of the distance between the machining contour and the outer contour of the blade tip is obtained by an image processing algorithm, and it is determined whether the minimum value is greater than a preset value. If so, the distance between the machining contour and the outer contour of the blade tip meets the preset requirements. If not, the blade is controlled to move in the X and Y axis directions of the machine tool and rotate in the C axis direction to adjust the position until the minimum value is greater than the preset value; Based on the first coordinate, the second coordinate and the third coordinate, a machining coordinate of the blade tip electrospark forming is obtained; The step of obtaining the machining coordinates of the blade tip electrospark forming based on the first coordinate, the second coordinate and the third coordinate specifically includes: Using the formula: X4= X3+( X1- X2), Y4= Y3+( Y1- Y2), The processing coordinates are obtained, wherein X4 is the X-axis coordinate of the processing coordinate, Y4 is the Y-axis coordinate of the processing coordinate, X1 is the X-axis coordinate of the first coordinate, Y1 is the Y-axis coordinate of the first coordinate, X2 is the X-axis coordinate of the second coordinate, Y2 is the Y-axis coordinate of the second coordinate, X3 is the X-axis coordinate of the third coordinate, and Y3 is the Y-axis coordinate of the third coordinate.

2. The method for adaptive positioning of turbine blade tip electrospark forming according to claim 1, characterized in that: The step of identifying the first image acquired by the rangefinder camera and extracting the processing contour specifically includes: Preprocessing the first image, wherein the preprocessing includes grayscale, contrast enhancement and binarization processing; On the preprocessed first image, obtaining boundary pixel points in the first image by using an edge detection algorithm; Through connectivity analysis, adjacent boundary pixel points are connected to obtain the processing contour.

3. The method for adaptive positioning of turbine blade tip electrospark forming according to claim 1, characterized in that: The identifying the second image acquired by the paraxial camera and extracting the outer contour of the blade tip specifically includes: Preprocessing the second image, wherein the preprocessing includes grayscale, contrast enhancement and binarization processing; On the preprocessed second image, obtaining boundary pixel points in the second image by using an edge detection algorithm; Through connectivity analysis, the adjacent boundary pixel points are connected to obtain the outer contour of the leaf tip.

4. The method for adaptive positioning of turbine blade tip electrospark forming according to claim 1, characterized in that: The obtaining of the minimum value of the distance between the machining contour and the outer contour of the blade tip by an image processing algorithm specifically includes: On the second image, setting a ruler with a known unit length; By comparing the ruler, the number of pixels between the machining contour and the outer contour of the blade tip is calculated; According to the corresponding relationship between the unit length of the ruler and the number of pixels, the number of pixels between the machining contour and the outer contour of the blade tip is converted into a distance; The minimum value of the distance is found by a traversal or search algorithm.

5. The method for adaptive positioning of turbine blade tip electrospark forming according to claim 1, characterized in that: After moving the blade to the center of the field of view of the paraxial camera, the method further includes: A paraxial camera is used to obtain the height difference between the blade tip surface and the cover plate set in the blade.

6. The method for adaptive positioning of turbine blade tip electrospark forming according to claim 1, characterized in that: The use of a profiling electrode to perform electrical discharge machining on a flat plate specifically includes: The machining depth of the electrical discharge machining is 1 mm to 2 mm greater than the chamfer radius of the electrode.

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