Turbine blade film hole automatic measuring device based on visual guidance

Abstract

The invention discloses a turbine blade film hole automatic measuring device based on visual guidance, and relates to the technical field of turbine blade film hole measurement, the turbine blade film hole automatic measuring device comprises a three-coordinate measuring machine, the mobile end of the three-coordinate measuring machine is provided with a sleeve and a camera, the sleeve is internally provided with a probe, the bottom of the probe extends out of the sleeve, and the angle of the camera is adjusted. The central point of the camera coincides with the central point of the probe, and a thin film pressure sensor is installed in the sleeve and makes contact with the probe. The air film hole is recognized through combination of the probe and the camera, the function of automatic pin insertion measurement is completed through visual guidance, manual visual inspection is not needed, precision is high, and time and labor are saved; and the three-coordinate measuring machine is adopted to control the movement of the probe, so that the cost is reduced, and the operation is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of turbine blade film hole measurement, and in particular to a turbine blade film hole automatic measurement device based on vision guidance. Background Art

[0002] The air film holes of turbine blades require corresponding measurement and calibration devices to detect their accuracy and quality control. However, since the location of the air film holes includes hole spacing, row spacing, the holes themselves include hole size and morphology, inner wall surface roughness and surface integrity and other data, the data type of the air film holes is too complex so that only contact or non-contact non-destructive testing technology can be used.

[0003] At present, the air film hole position measurement method adopted by domestic aero-engine blade factories is basically the visual comparison method. It is equivalent to measuring the surface roughness of components with surface roughness comparison samples. Since there is no calibration specification for the hole position standard blade in the country, there is no instrument that can calibrate its position parameters. Therefore, using an uncalibrated hole position standard blade as a physical standard comparison to measure the position of the blade air film hole does not meet the requirements of value traceability or transfer. Therefore, this method can only be operated by experienced skilled workers, and the existing equipment has large errors in visual measurement, which is time-consuming, labor-intensive, and inefficient.

[0004] Therefore, there is an urgent need for an automatic measurement device for turbine blade film holes based on vision guidance to solve the problems existing in the above-mentioned prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a device for automatically measuring film holes of turbine blades based on vision guidance, so as to solve the problems existing in the prior art.

[0006] To achieve the above-mentioned purpose, the present invention provides the following solution: The present invention provides an automatic measurement device for turbine blade air film holes based on visual guidance, including a three-coordinate measuring machine, wherein the mobile ends of the three-coordinate measuring machine are respectively equipped with a sleeve and a camera, a probe is installed in the sleeve, and the bottom of the probe extends out of the sleeve. The camera angle is adjusted so that the center point of the camera coincides with the center point of the probe, and a thin film pressure sensor is installed in the sleeve, and the thin film pressure sensor is in contact with the probe.

[0007] Preferably, a partition is installed in the sleeve, the film pressure sensor is installed at the end of the bottom surface of the partition, and the top of the probe is in contact with the film pressure sensor.

[0008] Preferably, a hollow sphere is rotatably connected in the sleeve, and one end of the partition away from the film pressure sensor is fixedly connected to the inner wall of the hollow sphere.

[0009] Preferably, a through hole is formed at the bottom of the hollow sphere, and the probe is adapted to fit into the through hole.

[0010] Preferably, an opening is provided at the bottom of the sleeve, the diameter of the opening is larger than the diameter of the probe, and the probe extends into the sleeve from the opening.

[0011] Preferably, an external thread is provided at the bottom of the sleeve, and the sleeve is detachably connected to a nut via the external thread, and the nut is used to fix the probe.

[0012] Preferably, a mounting frame is provided at the bottom of the movable end of the three-dimensional coordinate measuring machine, the top of the sleeve is fixedly connected to the mounting frame, the camera is rotatably connected to the mounting frame, and the camera is located on one side of the sleeve.

[0013] The present invention discloses the following technical effects: the present invention identifies the air film hole through the combination of the probe and the camera, completes the function of automatic pin measurement through visual guidance, does not require manual visual inspection, has high accuracy, saves time and effort; and adopts a three-coordinate measuring machine to control the movement of the probe, reduces costs, and facilitates operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0015] Figure 1 It is a structural schematic diagram of the present invention;

[0016] Figure 2 It is an assembly diagram of the sleeve and the nut of the present invention;

[0017] Figure 3 It is a schematic diagram of the internal structure of the sleeve of the present invention;

[0018] Figure 4 This is a logic diagram for identifying air film holes of the present invention;

[0019] Figure 5 This is a schematic diagram of the projection of the air film hole of the present invention;

[0020] Figure 6 It is an assembly diagram of the AX4 sensor and the hollow sphere of the present invention;

[0021] Figure 7 This is a flow chart of the air film hole identification code of the present invention;

[0022] Figure 8 It is an assembly diagram of the camera and the mounting bracket of the present invention;

[0023] In the figure: 1. three-dimensional coordinate measuring machine; 2. sleeve; 3. hollow sphere; 4. partition; 5. thin film pressure sensor; 6. through hole; 7. nut; 8. probe; 9. mounting bracket; 10. camera; 11. AX4 sensor. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Embodiment 1

[0027] Reference Figure 1-Figure 8 As shown, this embodiment provides an automatic measurement device for air film holes of turbine blades based on vision guidance, including a three-dimensional coordinate measuring machine 1. The mobile ends of the three-dimensional coordinate measuring machine 1 are respectively equipped with a sleeve 2 and a camera 10. A probe 8 is installed in the sleeve 2. The bottom of the probe 8 extends out of the sleeve 2. The angle of the camera 10 is adjusted so that the center point of the camera 10 coincides with the center point of the probe 8. A thin film pressure sensor 5 is installed in the sleeve 2, and the thin film pressure sensor 5 is in contact with the probe 8.

[0028] The image is acquired through the camera 10, and the air film hole recognition classifier is trained independently using the Python-OpenCV library to realize the detection and recognition of the air film hole. The probe 8 is guided to the center point of the air film hole through the visual guidance technology. When in use, the turbine blade is inspected through an S-shaped path. When the camera 10 and the pin cooperate to inspect the entire workbench, once the camera 10 recognizes the air film hole, it is necessary to stop the inspection and follow the guidance of the camera 10 to the top of the air film hole. The data of the X-axis and Y-axis of the three-dimensional coordinate measuring machine 1 at this time are recorded as the X-axis and Y-axis coordinates of the air film hole, and the Z-axis guide rail of the three-dimensional coordinate measuring machine 1 is controlled to insert the probe 8 into the air film hole. When the probe 8 is forced to move upward, it will eventually give a force to the thin film pressure sensor 5. When the force on the thin film pressure sensor 5 exceeds a certain value, this proves that At this time, the Z-axis position of the head point of the probe 8 is the Z-axis position of the air film hole. The current point is recorded, and the normal vector angle is determined using trigonometric functions. After completing the data collection of an air film hole, the regression camera 10 finds the position of the air film hole and continues to patrol the entire workbench to find the next air film hole until the camera 10 has patrolled the entire workbench to facilitate subsequent carbon removal operations on the air film holes. The air film holes are distributed throughout the turbine blades. Since the surface of the turbine blades is a curved surface, the angle of the axis of the air film hole relative to the horizontal plane may range from -90° to 90°, but the angle between the air film holes is rarely vertical. Therefore, when fixing the turbine blades, pay attention to the angle of the air film hole, and try not to be perpendicular to the direction of the camera 10 to prevent the camera 10 from failing to capture the image of the air film hole.

[0029] The present invention identifies the air film hole through the combination of the probe 8 and the camera 10, and completes the function of automatic pin measurement through visual guidance, without the need for manual visual inspection, with high accuracy, saving time and effort; and a three-coordinate measuring machine 1 is used to control the movement of the probe 8, which reduces costs and facilitates operation.

[0030] Furthermore, when the image of the air film hole is an ellipse, it means that the angle between the axis of the air film hole and the horizontal plane is not 90°. Since the image of the air film hole is the projection of the circular air film hole on the horizontal plane, it can be known that the longest radius of the ellipse is the same as the radius of the air film hole. Figure 5 As shown, it can be seen that there is a geometric relationship between the length of the short radius of the ellipse and the angle and length of the air film hole. The sum of the angle between the air film hole projection and the air film hole entity, and the angle between the air film hole axis and the horizontal plane is 90°; based on this relationship, after knowing the vertical values ​​of the long radius and the short radius in the elliptical image of the air film hole projection, assuming that the long radius is a and the short radius is b, the angle α between the air film hole axis and the horizontal plane can be obtained according to the formula α=arccos(b / a).

[0031] In a further optimized solution, a partition 4 is installed in the sleeve 2, and the film pressure sensor 5 is installed at the bottom end of the partition 4, and the top of the probe 8 contacts the film pressure sensor 5. The function of the partition 4 is to install the film pressure sensor 5 and support it.

[0032] According to a further optimized solution, a hollow sphere 3 is rotatably connected inside the sleeve 2 , and one end of the partition 4 away from the film pressure sensor 5 is fixedly connected to the inner wall of the hollow sphere 3 .

[0033] Furthermore, an AX4 sensor 11 is provided above the hollow sphere 3, and the diameter of the horizontal cutout in the upper part of the hollow sphere 3 is 20 mm, which is the same as the diameter of the spherical probe of the AX4 sensor 11; when the probe 8 is tilted due to force, the probe 8 will transfer the force to the hollow sphere 3, and the hollow sphere 3 will rotate and transfer the force to the AX4 sensor 11.

[0034] The use of a hollow sphere 3 for force transmission has the following advantages: the hollow sphere 3 can rotate in any direction, and compared to using a rod to transmit force, the probe 8 will not detach from the hollow sphere 3 and cause a malfunction; the wall of the sleeve 2 is tangent to the hollow sphere 3, so the hollow sphere 3 will not get stuck; the cutout in the upper part of the hollow sphere 3 is the same as the probe sphere diameter of the AX4 sensor 11, and the hollow sphere 3 and the probe need to have an interference fit, so there is no need to worry about the hollow sphere 3 detaching from the part when changing the angle during use. The AX4 sensor 11 can detect the direction of the shear stress, thereby providing assistance for the subsequent acquisition of the air film hole normal vector, and an indicator light can be added to facilitate the operator to more clearly confirm the force condition of the probe 8, and to respond quickly when a malfunction occurs to prevent damage to parts.

[0035] In a further optimized solution, a through hole 6 is provided at the bottom of the hollow sphere 3, and the probe 8 is adapted to the through hole 6. The through hole 6 at the lower half of the hollow sphere 3 has a diameter of 0.8, which is used to allow the probe 8 to pass through.

[0036] According to a further optimized solution, an opening is provided at the bottom of the sleeve 2 , the diameter of the opening is larger than the diameter of the probe 8 , and the probe 8 extends into the sleeve 2 from the opening.

[0037] According to a further optimized solution, an external thread is provided at the bottom of the sleeve 2 , and the sleeve 2 is detachably connected to a nut 7 via the external thread, and the nut 7 is used to fix the probe 8 .

[0038] According to a further optimization scheme, a mounting bracket 9 is provided at the bottom of the mobile end of the three-dimensional coordinate measuring machine 1 , the top of the sleeve 2 is fixedly connected to the mounting bracket 9 , the camera 10 is rotatably connected to the mounting bracket 9 , and the camera 10 is located on one side of the sleeve 2 .

[0039] Embodiment 2

[0040] Different from the first embodiment, the center deviation problem is solved by code. Since the probe 8 and the camera 10 are parallel, when the camera 10 guides the probe 8 to the center of the air film hole, the center of the probe 8 will inevitably fail to reach the center of the air film hole. However, the distance between the probe 8 and the center of the air film hole is fixed, that is, the distance from the center of the probe 8 to the center of the camera 10. Therefore, it is only necessary to move the probe 8 toward the camera 10 after the camera 10 guides it, and make up the distance from the center of the probe 8 to the center of the camera 10 to achieve the guiding purpose. The advantage of this method is that it is simple and direct, and there will be no additional errors.

[0041] Since the color difference between the air film hole and the turbine blade is large, the air film hole image collected by the camera 10 can be grayed, binarized, eroded, and expanded. At this time, the image area where the air film hole is located will become black pixels. By using the edge detection method (which can be implemented through code), the sum of the positions of all black pixels is divided by 2 to obtain the center point of all black pixels, that is, the center position of the air film hole.

[0042] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0043] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A vision-guided automatic measurement device for turbine blade film holes, characterized in that: The invention comprises a three-dimensional coordinate measuring machine (1), wherein a sleeve (2) and a camera (10) are respectively installed at the mobile end of the three-dimensional coordinate measuring machine (1), a probe (8) is installed in the sleeve (2), and the bottom of the probe (8) extends out of the sleeve (2), and the angle of the camera (10) is adjusted so that the center point of the camera (10) coincides with the center point of the probe (8), and a thin film pressure sensor (5) is installed in the sleeve (2), and the thin film pressure sensor (5) is in contact with the probe (8).

2. The automatic measurement device for film holes of turbine blades based on vision guidance according to claim 1 is characterized in that: A partition (4) is installed in the sleeve (2), the thin film pressure sensor (5) is installed at the end of the bottom surface of the partition (4), and the top of the probe (8) is in contact with the thin film pressure sensor (5).

3. The automatic measurement device for film holes of turbine blades based on vision guidance according to claim 2 is characterized in that: A hollow sphere (3) is rotatably connected inside the sleeve (2), and one end of the partition (4) away from the thin film pressure sensor (5) is fixedly connected to the inner wall of the hollow sphere (3).

4. The automatic measurement device for film holes of turbine blades based on vision guidance according to claim 3 is characterized in that: A through hole (6) is provided at the bottom of the hollow sphere (3), and the probe (8) is adapted to fit into the through hole (6).

5. The automatic measurement device for film holes of turbine blades based on vision guidance according to claim 1 is characterized in that: The bottom of the sleeve (2) is provided with an opening, the diameter of the opening is larger than the diameter of the probe (8), and the probe (8) extends into the sleeve (2) from the opening.

6. The automatic measurement device for film holes of turbine blades based on vision guidance according to claim 1 is characterized in that: The bottom of the sleeve (2) is provided with an external thread, and the sleeve (2) is detachably connected to a nut (7) via the external thread, and the nut (7) is used to fix the probe (8).

7. The automatic measurement device for film holes of turbine blades based on vision guidance according to claim 1 is characterized in that: A mounting frame (9) is provided at the bottom of the movable end of the three-dimensional coordinate measuring machine (1), the top of the sleeve (2) is fixedly connected to the mounting frame (9), the camera (10) is rotatably connected to the mounting frame (9), and the camera (10) is located on one side of the sleeve (2).

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