Pitch angle measuring structure and method for blade and aero-engine

Abstract

The invention provides a pitch angle measuring structure and method for a blade and an aero-engine. Wherein the blades are rotatably connected with the hub, and the rotating shaft is a Y axis; the pitch angle measuring structure comprises a visual mark and an optical measuring device. The visual mark comprises a first mark and a second mark which extend along the circumferential direction of the Y axis; the third mark extends in the axial direction of the Y axis; wherein the first mark, the second mark and the third mark form a pattern; in the pattern, the extending direction of the third mark passes through the first mark and intersects at a first intersection point, and passes through the second mark and intersects at a second intersection point; the distance between the first intersection point and the second intersection point varies synchronously with the pitch angle of the blade; the optical measuring device is configured to acquire an image of the pattern, so that the pitch angle of the blade is determined according to the distance between the first intersection point and the second intersection point in the pattern.

Description

Technical Field

[0001] The present application relates to the technical field of angle measurement, and in particular to a pitch angle measurement structure and method for blades, and an aircraft engine. Background Art

[0002] Aircraft engines are equipped with variable-pitch blades, which are adjusted according to different operating conditions to achieve efficient aerodynamic performance and reduce noise. Real-time measurement of the blade pitch angle during engine operation provides an important basis for monitoring and controlling flight conditions.

[0003] Currently, non-contact measurement of blade pitch angles in this field is usually achieved using a measurement structure consisting of a sensing component and an induction component made of ferromagnetic materials, such as a structure equipped with a Hall sensor. The principle is that the sensing component displaces as the pitch angle changes, thereby causing a change in the magnetic field. The induction component detects the magnetic field and converts it into an electrical signal, and indirectly infers the blade pitch angle based on the relationship between the electrical signal and the position of the sensing component.

[0004] However, the technical problems existing in the technical solution introduced above include but are not limited to: the sensing component itself occupies space and may adversely affect the working performance of the blade; and, since the adjustment range of the blade pitch angle is large, generally about 100°, the sensing component also requires a correspondingly larger activity space to cover the entire adjustment range, which is not conducive to the compact arrangement of the internal structure of the engine. If the activity space of the sensing component is limited, it will lead to measurement blind spots within the adjustment range; and, changes in the operating state and vibration of the engine may cause the position of the sensing component to deviate, adversely affecting the sensing of the induction component, resulting in deviations in the measurement results, etc.

[0005] Therefore, the art needs to develop a new pitch angle measurement structure, measurement method, and aircraft engine to solve at least one or a combination of the above technical problems. Summary of the Invention

[0006] The purpose of this application is to provide a pitch angle measurement structure for a blade.

[0007] Another object of the present application is to provide a method for measuring the pitch angle of a blade.

[0008] Another object of the present application is to provide an aircraft engine.

[0009] According to the first aspect of the present application, a pitch angle measurement structure for a blade; wherein the blade is rotatably connected to a hub, and the rotation axis is a Y-axis; the pitch angle measurement structure includes a visual mark and an optical measuring device; wherein the visual mark includes: a first mark and a second mark, extending circumferentially along the Y-axis; a third mark, extending axially along the Y-axis; and the first mark, the second mark and the third mark form a pattern; in the pattern, the extension direction of the third mark passes through the first mark and intersects at a first intersection, and passes through the second mark and intersects at a second intersection; the distance between the first intersection and the second intersection changes synchronously with the pitch angle of the blade; the optical measuring device is configured to be able to capture an image of the pattern to determine the pitch angle of the blade based on the distance between the first intersection and the second intersection in the pattern.

[0010] The pitch angle measurement structure described above replaces the electromagnetic measurement structure of the traditional scheme with visual markers and optical measuring devices, thereby eliminating the need to set up a sensing component made of ferromagnetic material, saving space for the installation and movement of the sensing component; compared with the sensing component of the traditional scheme, the use of visual markers has significantly less adverse effects on the engine's working performance, and avoids problems of looseness or wear caused by displacement, vibration, etc.; due to changes in the engine's operating state, vibration, etc., the relative position of the visual marker and the optical measuring device may be offset, thereby causing changes in the image's field of view, etc. Determining the pitch angle based on the third marker can reduce the adverse effects of changes in the field of view and improve the accuracy of the measurement results; the use of an optical measuring device is also suitable for obtaining clear images through high-speed photography, and compensation through image enhancement technology, etc., reducing the adverse effects of high-speed rotation, speed changes, vibrations, etc. of blades on the measurement, and improving the accuracy of the measurement results.

[0011] In one or more embodiments of the measurement structure, the first mark is configured as a spiral line extending circumferentially and axially along the Y-axis, and the second mark is configured as an annular line extending circumferentially along the Y-axis.

[0012] In one or more embodiments of the measurement structure, the first mark and the second mark are arranged on the blade or a structure that rotates synchronously with the blade relative to the hub; the third mark is arranged on the hub or a structure fixed relatively to the hub.

[0013] In one or more embodiments of the measuring structure, the pitch angle measuring structure includes a pitch angle adjustment device, the pitch angle adjustment device includes a first connecting part, the first connecting part is connected to the petiole of the blade, and the first connecting part rotates to adjust the pitch angle of the blade, and the first mark and the second mark are arranged on the outer surface of the first connecting part.

[0014] In one or more embodiments of the measurement structure, the hub and the plurality of blades can rotate synchronously, and the rotation axis is the X-axis; the optical measurement device includes an image acquisition unit for acquiring images; wherein, several of the image acquisition units are arranged to be fixed relative to the X-axis, so that a single image acquisition unit can measure the pitch angles of multiple blades.

[0015] In one or more embodiments of the measurement structure, a plurality of the image acquisition parts are provided on the hub corresponding to at least a portion of the blades.

[0016] In one or more embodiments of the measuring structure, a space is defined between the petiole of the blade and the image acquisition part; wherein, the end face of the hub extends inside the space, and the end face of the hub is provided with a measuring hole at a position corresponding to the visual mark, and the image acquisition part acquires an image of the visual mark through the measuring hole.

[0017] In one or more embodiments of the measurement structure, an end surface of the hub extends outside the space, and the image acquisition portion directly acquires an image of the visual mark.

[0018] In one or more embodiments of the measuring structure, a plurality of measuring holes are evenly distributed on the end surface of the hub.

[0019] In one or more embodiments of the measuring structure, the diameter of the measuring hole satisfies the relationship:

[0020] ;

[0021] Where, is the diameter of the measuring hole, is the distance between the center of the measuring hole and the image acquisition part, is the angle between the end face of the hub and the X-axis, is the distance between the visual marker and the image acquisition unit, is the maximum distance between the first intersection point and the second intersection point.

[0022] According to a second aspect of the present application, a pitch angle measurement method for a blade is provided, wherein the pitch angle of the blade is measured using the pitch angle measurement structure described in the first aspect. The pitch angle measurement method comprises the following steps:

[0023] S1. Collecting an image of the pattern;

[0024] S2. Obtain the distance between the first intersection and the second intersection in the pattern;

[0025] S3. Obtain the pitch angle of the blade according to the distance between the first intersection point and the second intersection point.

[0026] In one or more embodiments of the measuring method, step S1 includes:

[0027] The frame rate of the image acquisition is controlled to match the rotational speed of the wheel hub around the X-axis, satisfying the relationship:

[0028] ;

[0029] Where, is the frame rate of the image captured, is the number of blades measured, is the rotational speed of the hub.

[0030] In one or more embodiments of the measuring method, step S2 includes:

[0031] The image is processed using at least one of grayscale, Gaussian blur, and Canny edge detection, line segments in the image are detected using Hough transform, the first marker, the second marker, and the third marker are identified based on the slopes of the line segments, the first intersection point and the second intersection point are determined, and the distance between the first intersection point and the second intersection point is obtained.

[0032] In one or more embodiments of the measuring method, step S2 includes:

[0033] Artificial intelligence technology is used to process the image to obtain the distance between the first intersection point and the second intersection point.

[0034] In one or more embodiments of the measurement method, the pitch angle measurement structure is configured as follows: the first mark is an equidistant spiral line extending circumferentially and axially along the Y axis, and the second mark is an annular line extending only circumferentially along the Y axis; the pitch angle of the blade has an adjustment range ; The pitch angle of the blade is The corresponding distance between the first intersection point and the second intersection point is , the pitch angle of the blade is The distance between the first intersection point and the second intersection point is ; And, the step S3 includes:

[0035] According to the distance between the first intersection point and the second intersection point in any one of the patterns Calculate the corresponding pitch angle of the blade , satisfying the relationship:

[0036] .

[0037] An aircraft engine according to a third aspect of the present application includes the pitch angle measurement structure as described in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other features, properties and advantages of the present application will become more apparent through the following description in conjunction with the accompanying drawings and embodiments. In the accompanying drawings, the same reference numerals always represent the same features. It should be noted that these drawings are only for illustration and are not drawn to scale. They should not be used to limit the actual scope of protection claimed in this application. Among them:

[0039] Figure 1 The figure is a schematic diagram of the partial structure of an aircraft engine according to an embodiment.

[0040] Figure 2 Schematic diagram of the partial structure of a blade according to an embodiment.

[0041] Figure 3 Schematic diagram of the structure of a wheel hub according to an embodiment.

[0042] Figure 4 Schematic diagram of the pitch angle measurement structure according to an embodiment.

[0043] Figure 5 Schematic diagram of the structure of a visual marker according to an embodiment.

[0044] Figure 6 Schematic diagram of blade pitch angles and corresponding visual marking patterns according to an embodiment.

[0045] Figure 7 A schematic diagram of the partial structure of an aircraft engine according to another embodiment.

[0046] Figure 8 It is a schematic diagram of the partial structure of a blade in another embodiment.

[0047] Figure 9 The figure is a schematic diagram of the partial structure of an aircraft engine according to another embodiment.

[0048] Figure 10 FIG. 1 is a flow chart of a method for measuring a blade pitch angle according to an embodiment of the present invention.

[0049] Reference numerals:

[0050] 1. Aircraft engines;

[0051] 2. Pitch angle adjustment device; 21. First connection portion; 211. First mark; 212. Second mark;

[0052] 3. Leaf blade; 31. Petiole;

[0053] 4. Hub; 41. End face of hub; 411. Measuring hole; 412. Third mark; 42. Second connecting portion;

[0054] 5. Image acquisition unit;

[0055] 6. Installation structure;

[0056] 7. Image processing unit. DETAILED DESCRIPTION

[0057] Reference will now be made in detail to the various embodiments of the present application, examples of which are shown in the accompanying drawings and are described below. Although the present application will be described in conjunction with the exemplary embodiments, it should be appreciated that the present application is not intended to be limited to those exemplary embodiments. On the contrary, the present application is intended to cover not only these exemplary embodiments, but also various alternative forms, modifications, equivalent forms, and other embodiments that may be included within the spirit and scope of the present application as defined by the appended claims.

[0058] This application uses specific terms to describe the embodiments of this application. For example, "one embodiment" and / or "an embodiment" means a feature, structure or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" mentioned twice or more in different places in this application does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of this application can be appropriately combined. In the subsequent description, the orientation or position relationship indicated by "upper", "lower", "inner", "outer", "front", "back" or other directional terms is based on the orientation or position relationship shown in the accompanying drawings. It is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or component referred to must have a specific orientation, be constructed and / or implemented in a specific orientation. Therefore, it should not be understood as limiting this application. In this application, the terms "first", "second", etc. are only used to distinguish descriptions and should not be understood as indicating or implying positional relationships or importance rankings. In the following description, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc. should be understood in a broad sense; for example, they can refer to fixed connections or movable connections; they can refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of this application based on specific circumstances.

[0059] This application uses flowcharts to illustrate the operations performed according to the embodiments of this application. It should be appreciated that, depending on the actual situation, the steps do not necessarily need to be performed in the order shown in the diagrams, and other operations may be added to these processes, or one or more steps may be removed from these processes.

[0060] It can be understood that the pitch angle measurement structure and measurement method provided in the present application are suitable for measuring the pitch angle of the fan blades of an aircraft engine, and can also be applied to other applicable occasions, as long as the pitch angle of the blades of the measurement device needs to be measured and the pitch angle measurement structure disclosed in the embodiment of the present application can be applied, but it is not limited to this.

[0061] See also Figure 1 、 Figure 7 、 Figure 9 The aircraft engine 1 shown is generally symmetrical about the X-axis. Several blades 3 extend radially from a hub 4 along the X-axis and are connected to the hub 4 via blade shanks 31. The blades 3 are rotatably connected to the hub 4 to adjust the pitch angle, with the axis of rotation being the Y-axis extending radially along the X-axis. Specifically, in some embodiments, the pitch angle adjustment device 2 includes a first connection portion 21 (e.g., a rocker arm), which is connected to the blade shank 31 and can rotate to drive the pitch angle of the blades 3. The hub 4 includes a second connection portion 42, to which the blade shank 31 is plugged via a bearing or bushing, thereby being supported by the hub 4. In some embodiments, the hub 4 and blades 3 are also rotatable about the X-axis, thus forming rotor blades.

[0062] See also Figures 1 to 9 The pitch angle measurement structure shown in the figure includes a visual mark and an optical measuring device; wherein the visual mark includes: a first mark 211 and a second mark 212 extending circumferentially along the Y axis; a third mark 412 extending axially along the Y axis; and the first mark 211, the second mark 212 and the third mark 412 form a pattern; in the pattern, the extension direction of the third mark 412 (the extension line of the third mark 412) passes through the first mark 211 and intersects at a first intersection b, and passes through the second mark 212 and intersects at a second intersection c; the distance between the first intersection b and the second intersection c changes synchronously with the pitch angle of the blade 3; the optical measuring device is configured to be able to capture an image of the pattern of the visual mark to determine the pitch angle of the blade 3 based on the distance between the first intersection b and the second intersection c in the pattern.

[0063] The pitch angle measurement structure described above replaces the electromagnetic measurement structure of the traditional scheme with a pitch angle measurement structure composed of a visual marker and an optical measuring device, so there is no need to set up a sensing component made of ferromagnetic material, saving space for the installation and movement of the sensing component; compared with the sensing component of the traditional scheme, the adverse effect of the visual marker on the engine working performance is significantly smaller, and the problem of looseness or wear caused by displacement, vibration, etc. is avoided; due to changes in the engine operating state, vibration, etc., the relative position of the visual marker and the optical measuring device may be offset, thereby causing the field of view of the image to change, etc. Determining the pitch angle based on the third marker 412 can reduce the adverse effect of the field of view change and improve the accuracy of the measurement results; the use of an optical measuring device is also suitable for obtaining clear images through high-speed photography, and compensation through image enhancement technology, etc., reducing the adverse effects of high-speed rotation, speed changes, vibrations, etc. of the blade 3 on the measurement, and improving the accuracy of the measurement results.

[0064] Specifically, a visual mark refers to an identification that can be sensed by an optical measuring device, which can be formed by applying paint or engraving; generally, the visual mark can be configured to be clearly visible within the typical engine overhaul time interval without falling off, wearing or corroding, etc., to ensure the reliability and service life of the measuring structure. The above-mentioned circumferential extension of the first mark 211 and the second mark 212 along the Y axis means that the extension direction of the first mark 211 and the second mark 212 has at least a circumferential component along the Y axis; the axial extension of the third mark 412 along the Y axis means that the extension direction of the third mark 412 has at least an axial component along the Y axis; and, in order to make the distance between the first intersection b and the second intersection c in the pattern change synchronously with the pitch angle of the blade 3, at least one of the first mark 211 and the second mark 212 also has an axial extension component along the Y axis; in some embodiments, the first mark 211 and the second mark 212 are configured so that the distance between the first intersection b and the second intersection c has a one-to-one correspondence with the pitch angle of the blade 3, that is, there is no situation where the same distance between the first and second intersections corresponds to multiple pitch angles, thereby avoiding mismeasurement; for example, the first mark 211 gradually approaches or moves away from the second mark 212, so that the distance between the first and second intersections changes monotonically. For example Figures 2 to 6 As shown, the first mark 211 can be a spiral line relatively fixed to the blade 3 and extending along the circumferential and axial directions of the Y-axis, the second mark 212 can be an annular line relatively fixed to the blade 3 and extending only around the circumferential direction of the Y-axis, and the third mark 412 can be a straight line extending along the Y-axis (radial direction of the hub 4) on the hub 4. Therefore, when the pitch angle of the blade 3 changes, the first mark 211 and the second mark 212 move relative to the third mark 412, so that the pattern changes accordingly, as shown in FIG. Figure 6As shown; the visual marker can also be configured in other structures, for example, the first marker 211 and the second marker 212 can also be spirals with unequal pitches, without limitation. It can be understood that the pitch angle measurement structure described above is particularly suitable for arranging the visual marker and the optical measurement device approximately along the X-axis. The visual marker and the optical measurement device can also be arranged in other orientations, for example, approximately along the Y-axis, as long as the visual marker pattern and the image acquisition unit are arranged facing each other, without limitation.

[0065] like Figure 1 、 Figure 7 、 Figure 9 As shown, the optical measuring device may include an image acquisition unit 5 and an image processing unit 7; the image acquisition unit 5 is used to acquire an image of the pattern, and is arranged opposite to the visual mark, and its field of view covers at least a portion of the pattern formed by the first mark 211, the second mark 212 and the third mark 412; generally, the image acquisition unit 5 can be configured as a high-speed camera; the image acquisition unit 5 and the image processing unit 7 are connected by wire or wirelessly to transmit images; the image processing unit 7 is used to receive the image of the pattern from the image acquisition unit 5, and determine the pitch angle of the blade 3 according to the distance between the first intersection b and the second intersection c in the pattern; generally, the image processing unit 7 may include a processor and a memory; the memory is used to store instructions executable by the processor, and the processor is used to execute the instructions to implement the steps of the method for obtaining the pitch angle of the blade 3 according to the received image. In some embodiments, the image processing unit 7 also includes a communication device for transmitting the measurement result of the pitch angle to the monitoring and control system of the engine, but is not limited to this.

[0066] The image acquisition unit 5, image processing unit 7, memory, and processor described above are not limited to a specific image acquisition unit 5, image processing unit 7, memory, or processor. For example, in some cases, at least one of the image acquisition unit 5, image processing unit 7, memory, and processor may have a distributed structure, for example, including memory and processors located on the sensing device and in the backend cloud, to jointly implement pitch angle measurement. Furthermore, in embodiments employing a distributed structure, the specific execution terminal of each step may be adjusted based on actual conditions, and the specific implementation of each step on a specific terminal should not limit the scope of protection of the present invention.

[0067] In some embodiments, the image acquisition unit 5 is configured to be able to adjust the image acquisition; for example, in some embodiments, the blade 3 is a rotor blade that can rotate around the X-axis, and the image acquisition unit 5 is arranged relatively fixed to the X-axis and does not rotate with the blade 3. By adjusting the frame rate of image acquisition to match the rotation speed of the rotor blade, images corresponding to several visual marks are accurately acquired, and by adjusting the exposure time of image acquisition to ensure image clarity, etc., the present invention is not limited to this.

[0068] See also Figure 2 、 Figure 3 、 Figure 8 As shown, in one or more embodiments, the first mark 211 and the second mark 212 are provided on the blade 3 or a structure that rotates synchronously with the blade 3 relative to the hub 4 around the Y-axis; the third mark 412 is provided on the hub 4 or a structure that is relatively fixed to the hub 4, that is, the third mark 412 is provided on a structure that does not rotate with the blade 3 around the Y-axis. For example, the pitch angle measurement structure may also include a pitch angle adjustment device 2, the pitch angle adjustment device 2 including a first connection portion 21 (such as a rocker arm), the first connection portion 21 being connected to the petiole 31 and being rotatable to adjust the pitch angle of the blade 3, the first mark 211 and the second mark 212 being provided on the outer surface of the first connection portion 21, as shown in FIG. Figure 2 As shown; the hub 4 may further include an end face 41 of the hub and a second connecting portion 42, the petiole 31 being inserted into the second connecting portion 42, the end face 41 of the hub providing support for the blade 3 and the second connecting portion 42; wherein the third mark 412 may be provided on the end face 41 of the hub, as shown Figure 3 It can also be provided at the second connecting portion 42, as shown; Figure 8 As shown; in this way, the form of the visual mark can be flexibly selected according to the internal structure of the engine.

[0069] In some embodiments, the first marker 211 is configured as a spiral line extending circumferentially and axially along the Y-axis, for example, an equidistant spiral line; the second marker 212 is configured as a circumferential annular line around the Y-axis; in this way, the first marker 211 and the second marker 212 can be distinguished and identified based on the slope of each line segment in the image, and it is helpful to establish the relationship between the distance between the first intersection point b and the second intersection point c and the pitch angle of blade 3 to simplify the calculation.

[0070] like Figure 1 、 Figure 7As shown, in one or more embodiments, the blades 3 are configured as rotor blades, and the hub 4 and the plurality of blades 3 can rotate synchronously with the X-axis as the rotation axis; the optical measuring device further includes a mounting structure 6 of the image acquisition unit 5, and the mounting structure 6 is arranged to be fixed relative to the X-axis, so that the image acquisition unit 5 does not rotate with the hub 4 and the blades 3, so that the plurality of blades 3 can pass through positions facing the same image acquisition unit 5 when rotating, so that a single image acquisition unit 5 can measure the pitch angles of the plurality of blades 3, for example, measure all the blades 3, which is conducive to reducing the number of image acquisition units 5, saving space and cost, etc.; it should be noted that the number of image acquisition units 5 is not limited to one, and the use of multiple image acquisition units 5 is conducive to improving the accuracy and reliability of the measurement, etc.

[0071] like Figure 9 As shown, in one or more embodiments, a plurality of image acquisition parts 5 are provided on the hub 4 corresponding to at least a portion of the blades 3. The hub 4 provides installation positions for the blades 3 and corresponding installation positions for the image acquisition parts 5. Generally, the plurality of image acquisition parts 5 can be evenly distributed on the hub 4 to prevent dynamic imbalance problems.

[0072] like Figure 1 、 Figure 7 、 Figure 9 As shown, a space is defined between the petiole 31 and the image acquisition unit 5. In some embodiments, as Figure 1 As shown, the end face 41 of the hub is located between the petiole 31 and the image acquisition unit 5 and extends inside the space. A light-transmitting measuring hole 411 is provided on the end face 41 of the hub at a position corresponding to the visual mark, and the image acquisition unit 5 acquires an image of the visual mark through the measuring hole 411. In other embodiments, the end face 41 of the hub is not located between the visual mark and the image acquisition unit 5 but extends outside the space, so that the hub 4 does not block the field of view of the image acquisition unit 5, and the image acquisition unit 5 can directly acquire an image of the visual mark, thereby eliminating the need for a measuring hole; for example Figure 7 As shown, the end face 41 of the hub extends on one side of the blade stalk 31 along the X-axis direction (for example, the front side of the engine), and the image acquisition unit 5 is fixed on the other side along the X-axis direction (for example, the rear side of the engine); or as shown Figure 9 As shown, the image acquisition unit 5 can also be fixed on the end face 41 of the hub.

[0073] like Figure 3 As shown, in one or more embodiments, a plurality of measuring holes 411, such as two or three, are evenly distributed on the end face 41 of the hub. This facilitates measuring the pitch angles of the plurality of blades 3 to ensure that the measurement results are accurate and reliable, and can monitor the working conditions of the plurality of blades 3 and make the mass distribution uniform to prevent dynamic imbalance problems.

[0074] like Figure 4 As shown, in one or more embodiments, the diameter of the measuring hole 411 satisfies the relationship:

[0075] ;

[0076] Where, is the diameter of the measuring hole 411, is the distance between the center of the measuring hole 411 and the image acquisition part 5, is the angle between the end face 41 of the hub and the X-axis, is the distance between the visual marker and the image acquisition unit 5, is the maximum distance between the first intersection point b and the second intersection point c.

[0077] By limiting the minimum size of the measuring hole 411, it is ensured that the field of view of the optical collection unit through the measuring hole 411 can effectively cover the pattern with the largest distance between the first intersection b and the second intersection c, avoiding measurement blind spots within the pitch angle adjustment range.

[0078] See also Figure 10 The pitch angle measurement method for the blade 3 shown uses the above pitch angle measurement structure to measure the pitch angle of the blade 3; the pitch angle measurement method includes the following steps:

[0079] S1. Collecting pattern images;

[0080] S2. Get the distance between the first intersection point b and the second intersection point c in the pattern;

[0081] S3. Obtain the pitch angle of blade 3 according to the distance between the first intersection point b and the second intersection point c.

[0082] In one or more embodiments, step S1 specifically includes:

[0083] The image acquisition unit 5 obtains the rotor blade speed information from the engine monitoring and control system, and automatically controls the image acquisition frame rate accordingly, so that the acquisition frame rate matches the rotor speed, thereby ensuring that each frame of the acquired image corresponds to a visual mark detection result, reducing unnecessary image acquisition and improving the image data processing efficiency. The acquisition frame rate is controlled to meet the relationship:

[0084] ;

[0085] Where, is the frame rate of the captured image, is the number of blades 3 measured, is the rotational speed of the hub 4.

[0086] like Figure 5 、 Figure 6As shown, in one or more embodiments, step S2 specifically includes:

[0087] The image is preprocessed using at least one of grayscale, Gaussian blur, and Canny edge detection, and then line segments in the image are detected using Hough transform. The first marker 211, the second marker 212, and the third marker 412 are identified based on the slope of the line segments. The third marker 412 intersects the contour line of the measuring hole 411 at points a and d, and the line segment direction of the third marker 412 intersects the first marker 211 and the second marker 212 at the first intersection b and the second intersection c, respectively. The distance between the first intersection b and the second intersection c is calculated. This method helps reduce the amount of calculation and noise signal interference. Step S2 can also use other methods to obtain the distance between the first intersection b and the second intersection c. For example, artificial intelligence technology can be used to process the image, and by collecting image data in complex and diverse operating scenarios, the artificial intelligence model is trained and optimized based on the image data, thereby achieving accurate recognition of the visual markers and calculating the distance between the two intersections based on the recognition results. The present invention is not limited to this.

[0088] like Figure 6 As shown, in one or more embodiments, step S3 specifically includes:

[0089] In advance, within the adjustment range of the pitch angle, the corresponding multiple pitch angles are obtained The distance between the first intersection point b and the second intersection point c , thereby establishing the distance between the first intersection point b and the second intersection point c within the adjustment range of the pitch angle Pitch angle with blade 3 The correspondence between them.

[0090] Specifically, the pitch angle measurement structure can also be configured so that the pitch angle of the blade 3 has an adjustment range of The first mark 211 is an equidistant spiral extending in the circumferential and axial directions along the Y axis, and the second mark 212 is an annular line extending only in the circumferential direction along the Y axis, so that the distance between the first intersection point b and the second intersection point c is Pitch angle with blade 3 A linear relationship is formed between them, and only two critical values ​​of the pitch angle adjustment range need to be pre-set. The corresponding image can be calibrated, and the pitch angle of blade 3 is The distance between the corresponding first intersection point b and the second intersection point c is , the pitch angle of blade 3 is The distance between the first intersection point b and the second intersection point c is ; According to the distance between the first intersection b and the second intersection c in any pattern collected , the corresponding pitch angle of blade 3 can be calculated , satisfying the relationship:

[0091] .

[0092] In some embodiments, the measurement method further includes transmitting the measured pitch angle information of the blade 3 to a monitoring and control system of the engine, but is not limited thereto.

[0093] like Figure 1 、 Figure 7 、 Figure 9 The aircraft engine 1 shown includes the above pitch angle measurement structure, which is used to measure the pitch angle of the fan blades of the aircraft engine 1.

[0094] The present application is described below using an embodiment of a pitch angle measurement structure and method for measuring fan blades of an aircraft engine 1 as an example, but the invention is not limited thereto. Figure 1 As shown, the image acquisition unit 5 is equipped with one or more high-speed cameras and is arranged on a mounting structure 6. The mounting structure 6 is relatively fixed to the X-axis and does not rotate around the X-axis with the hub 4 and the fan blade 3. The end face 41 of the hub is located between the high-speed camera and the blade stalk 31, and three measuring holes 411 are opened on the end face 41 of the hub to avoid blocking the field of view of the high-speed camera.

[0095] X-axis distance between high-speed camera and visual marker The distance between the center of the measuring hole 411 and the high-speed camera in the X-axis direction is 300 mm. The maximum Y-axis distance between the first mark 211 and the second mark 212 is 150 mm. The angle between the end face 41 of the hub and the X axis is 100 mm. is 45°, then the diameter of the measuring hole 411 Satisfies the relationship:

[0096]

[0097] Image acquisition frame rate Automatically controlled to match the speed of the rotor blades , ensuring that each frame of the collected image corresponds to a visually marked pattern, satisfying the relationship:

[0098]

[0099] For example, when the rotation speed is 25r / s, the corresponding acquisition frame rate is 75f / s.

[0100] The adjustment range of blade 3 pitch angle is configured as , maximum pitch angle for The distance between the two intersection points of the corresponding patterns for ;Minimum pitch angle for The distance between the two intersection points of the corresponding patterns for The first mark 211 and the second mark 212 are configured as equidistant spirals and circular lines respectively; the high-speed camera captures an image of any pattern within the adjustment range, and the distance between the first intersection b and the second intersection c is obtained through image processing. , according to the distance Calculate the blade 3 pitch angle corresponding to the image acquisition moment , satisfying the relationship:

[0101]

[0102] For example, according to the image at a certain moment, the distance between the first intersection point b and the second intersection point c is , then the pitch angle of blade 3 at this moment can be obtained as:

[0103] .

[0104] In summary, the beneficial technical effects of this application include but are not limited to at least one of the following:

[0105] The pitch angle measurement structure composed of visual markers and optical measuring devices replaces the electromagnetic measurement structure of the traditional solution, so there is no need to set up a sensing component made of ferromagnetic material, saving space for the installation and movement of the sensing component; compared with the sensing component of the traditional solution, the adverse effect of the visual marker on the engine working performance is significantly smaller, and the problem of looseness or wear caused by displacement, vibration, etc. is avoided; due to changes in the engine operating state, vibration, etc., the relative position of the visual marker and the optical measuring device may be offset, thereby causing the field of view of the image to change, etc. Determining the pitch angle based on the third marker can reduce the adverse effect of the field of view change and improve the accuracy of the measurement results; the use of the optical measuring device is also suitable for obtaining clear images through high-speed photography, and compensation through image enhancement technology, etc., reducing the adverse effects of high-speed rotation of the blades, speed changes, vibrations, etc. on the measurement, and improving the accuracy of the measurement results.

[0106] Although the present application discloses the preferred embodiments as described above, they are not intended to limit the present application. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modifications, equivalent variations, and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application shall fall within the scope of protection defined by the claims of the present application.

Claims

1. A pitch angle measurement structure for a blade, characterized in that: The blade is rotatably connected to the hub, and the rotation axis is the Y axis; the pitch angle measurement structure includes a visual marker and an optical measurement device; wherein, The visual markers include: A first mark and a second mark extending along the circumference of the Y axis; A third mark extends along the axial direction of the Y axis; and The first mark, the second mark, and the third mark form a pattern; in the pattern, an extension direction of the third mark passes through the first mark and intersects at a first intersection point, and passes through the second mark and intersects at a second intersection point; a distance between the first intersection point and the second intersection point changes synchronously with a pitch angle of the blade; The optical measuring device is configured to capture an image of the pattern to determine the pitch angle of the blade based on the distance between the first intersection point and the second intersection point in the pattern.

2. The measurement structure according to claim 1, characterized in that The first mark is configured as a spiral line extending along the circumferential direction and the axial direction of the Y-axis, and the second mark is configured as an annular line extending along the circumferential direction of the Y-axis.

3. The measurement structure according to claim 1, characterized in that The first mark and the second mark are set on the blade or a structure that rotates synchronously with the blade relative to the hub; the third mark is set on the hub or a structure fixed relatively to the hub.

4. The measurement structure according to claim 1, characterized in that The pitch angle measurement structure includes a pitch angle adjustment device, which includes a first connecting part, the first connecting part is connected to the petiole of the blade, and the first connecting part rotates to adjust the pitch angle of the blade, and the first mark and the second mark are arranged on the outer surface of the first connecting part.

5. The measurement structure according to claim 1, characterized in that The hub and the plurality of blades can rotate synchronously, and the rotation axis is the X axis; the optical measuring device includes an image acquisition unit for acquiring images; wherein, Several image acquisition units are fixedly arranged relative to the X-axis, so that a single image acquisition unit can measure the pitch angles of multiple blades; or several image acquisition units are arranged on the hub corresponding to at least some of the blades.

6. The measurement structure according to claim 1, characterized in that The optical measuring device includes an image acquisition part for acquiring images, and a space is defined between the petiole of the leaf and the image acquisition part; wherein, The end face of the wheel hub extends inside the space, and the end face of the wheel hub is provided with a measuring hole at a position corresponding to the visual mark, and the image acquisition unit acquires an image of the visual mark through the measuring hole; alternatively, the end face of the wheel hub extends outside the space, and the image acquisition unit directly acquires an image of the visual mark.

7. The measurement structure according to claim 6, characterized in that A plurality of measuring holes are evenly distributed on the end surface of the hub; and / or the diameters of the measuring holes satisfy the relationship: ； Where, is the diameter of the measuring hole, is the distance between the center of the measuring hole and the image acquisition part, is the angle between the end face of the hub and the X-axis, is the distance between the visual marker and the image acquisition unit, is the maximum distance between the first intersection point and the second intersection point.

8. A method for measuring the pitch angle of a blade, characterized in that: The pitch angle of the blade is measured using the pitch angle measurement structure according to any one of claims 1 to 7; the pitch angle measurement method comprises the following steps: S1. Collecting an image of the pattern; S2. Obtain the distance between the first intersection and the second intersection in the pattern; S3. Obtain the pitch angle of the blade according to the distance between the first intersection point and the second intersection point.

9. The measuring method according to claim 8, characterized in that The pitch angle measurement method further includes: The step S1 comprises: The image acquisition frame rate is controlled to match the rotation speed of the blade around the X-axis to satisfy the relationship: ； Where, is the frame rate of the image captured, is the number of blades measured, is the rotational speed of the blade; and / or, The step S2 comprises: Processing the image using at least one of grayscale, Gaussian blur, and Canny edge detection, detecting line segments in the image using a Hough transform, identifying the first marker, the second marker, and the third marker based on the slopes of the line segments, determining the first intersection point and the second intersection point, and obtaining the distance between the first intersection point and the second intersection point; or processing the image using artificial intelligence technology to obtain the distance between the first intersection point and the second intersection point. and / or, The pitch angle measurement structure is configured as follows: the first mark is an equidistant spiral line extending circumferentially and axially along the Y axis, and the second mark is an annular line extending circumferentially along the Y axis; the pitch angle of the blade has an adjustment range ; The pitch angle of the blade is The corresponding distance between the first intersection point and the second intersection point is , the pitch angle of the blade is The distance between the first intersection point and the second intersection point is ; And, the step S3 includes: According to the distance between the first intersection point and the second intersection point in any one of the patterns Calculate the corresponding pitch angle of the blade , satisfying the relationship: 。 10. An aircraft engine, characterized in that: The method comprises the pitch angle measurement structure according to any one of claims 1 to 7.

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