A measuring system, method and device for the blade pitch angle of a wind turbine generator

Abstract

An embodiment of the present application discloses a measurement system, method and device for the pitch angle of a wind turbine blade. Among them, the method includes: obtaining a target image including position markers captured by an image acquisition device, the image acquisition device being fixedly installed at a position capable of capturing a target circumference on the pitch bearing, a plurality of position markers being distributed on the target circumference, and an identifier being provided on the surface of the position marker; determining a target displacement of the position marker in the target image relative to the initial position marker in the initial image according to the pixel positions corresponding to the position markers in the target image and the pixel positions corresponding to the initial position markers in the initial image captured by the image acquisition device, the initial position marker corresponding to an initial pitch angle; determining the pitch angle corresponding to the target image according to the target displacement, the diameter of the target circumference and the initial pitch angle. In this way, accurate measurement of the pitch angle of the wind turbine is ensured.

Description

Technical Field

[0001] This application relates to the technical field of pitch angle measurement of wind turbines, and particularly to a measurement system, method, and device for the pitch angle of blades of a wind power generation unit. Background Art

[0002] As one of the core parts of the control system of a large wind turbine, the pitch system plays a very important role in the safe, stable, and efficient operation of the unit. The pitch angle of a blade refers to the angle between the chord line of the airfoil at the tip of the blade and the rotation plane. When the wind turbine reaches its rated power, the pitch system issues control commands to adjust the rotational speed of the pitch motor according to the change in wind speed, thereby adjusting the pitch angle of the blade to ensure the normal operation of the wind turbine. In addition, during the startup, shutdown, and emergency shutdown of the wind turbine, the pitch system also adjusts the pitch angle of the blade to meet the startup and shutdown requirements. In short, safely and stably controlling the pitch angle of the wind turbine plays an extremely important role in the normal operation of the wind power generation unit.

[0003] An important prerequisite for safely and stably controlling the pitch angle is to be able to accurately monitor the pitch angle. Currently, most relevant institutions at home and abroad generally use rotary encoders to monitor the pitch angle. A rotary encoder is a speed and displacement sensor integrating opto-mechatronics technology. When the shaft of the rotary encoder drives the grating disk to rotate, the light emitted by the light-emitting element will be cut into intermittent light by the slits of the grating disk. The receiving element receives the intermittent light and uses relevant circuits to process the intermittent light to obtain corresponding pulse or code signals, and then monitors the pitch angle based on the pulse or code signals obtained in this way.

[0004] However, using a rotary encoder to measure the pitch angle is an indirect measurement, and the accuracy of the measurement result completely depends on the measurement performance of the rotary encoder. In many cases, this measurement method cannot ensure the accuracy of the monitored pitch angle. Summary of the Invention

[0005] Embodiments of this application provide a measurement system, method, and device for the pitch angle of blades of a wind power generation unit.

[0006] In view of this, in the first aspect of this application, a method for measuring the pitch angle of blades of a wind power generation unit is provided, and the method includes:

[0007] Obtain a target image including position marks captured by an image acquisition device, where the image acquisition device is fixedly installed at a position capable of capturing the target circumference on the pitch bearing, multiple position marks are distributed on the target circumference, and identifiers are provided on the surfaces of the position marks;

[0008] Determine the target displacement of the position marker in the target image relative to the initial position marker in the initial image according to the pixel position corresponding to the position marker in the target image and the pixel position corresponding to the initial position marker in the initial image captured by the image acquisition device; the initial position marker corresponds to the initial pitch angle;

[0009] Determine the pitch angle corresponding to the target image according to the target displacement, the diameter of the target circumference, and the initial pitch angle.

[0010] The second aspect of the present application provides a measuring device for the pitch angle of a wind turbine blade, the device includes:

[0011] An image acquisition module, configured to acquire a target image including a position marker captured by an image acquisition device; the image acquisition device is fixedly installed at a position on a target circumference capable of capturing a pitch bearing; a plurality of position markers are distributed on the target circumference, and an identifier is provided on the surface of the position marker;

[0012] A displacement determination module, configured to determine the target displacement of the position marker in the target image relative to the initial position marker in the initial image according to the pixel position corresponding to the position marker in the target image and the pixel position corresponding to the initial position marker in the initial image captured by the image acquisition device; the initial position marker corresponds to the initial pitch angle;

[0013] A pitch angle determination module, configured to determine the pitch angle corresponding to the target image according to the target displacement, the diameter of the target circumference, and the initial pitch angle.

[0014] The third aspect of the present application provides a measuring system for the pitch angle of a wind turbine blade, the system includes: an image acquisition device and a processor, and the image acquisition device is communicatively connected to the processor;

[0015] The image acquisition device is fixedly installed at a position on a target circumference capable of capturing a pitch bearing, a plurality of position markers are distributed on the target circumference, and an identifier is provided on the surface of the position marker;

[0016] The image acquisition device is configured to capture the position markers provided on the target circumference;

[0017] The processor is configured to execute the method for measuring the pitch angle of a wind turbine blade described in the first aspect above.

[0018] The fourth aspect of the present application provides a computer-readable storage medium, which is used to store a computer program, and the computer program is used to execute the method for measuring the pitch angle of a wind turbine blade described in the first aspect above.

[0019] The fifth aspect of the present application provides a computer product including instructions, which, when running on a computer, cause the computer to execute the method for measuring the blade pitch angle of a wind turbine generator set described in the first aspect above.

[0020] As can be seen from the above technical solutions, the embodiments of the present application have the following advantages:

[0021] The embodiments of the present application provide a method for measuring the blade pitch angle of a wind turbine generator set. This method realizes the direct measurement of the pitch angle based on a machine vision algorithm, effectively ensuring the accuracy of the pitch angle measurement. Specifically, in the method for measuring the blade pitch angle of a wind turbine generator set provided by the embodiments of the present application, first, a target image including position marks captured by an image acquisition device is obtained. Here, the image acquisition device is fixedly installed at a position where it can capture the target circumference on the pitch bearing. A plurality of position marks are distributed on the target circumference, and different identifiers are provided on the surfaces of these plurality of position marks; then, according to the pixel positions corresponding to the position marks in the target image and the pixel positions corresponding to the initial position marks in the initial image captured by the image acquisition device, the target displacement of the position marks in the target image relative to the initial position marks is determined. Here, the initial position marks correspond to the initial pitch angle; furthermore, according to the above target displacement, the diameter of the target circumference, and the initial pitch angle, the pitch angle corresponding to the target image is determined.

[0022] Compared with the prior art solution for measuring the pitch angle based on a rotary encoder, the technical solution provided by the embodiments of the present application can overcome the uncertainty of the pitch angle caused by the root twist vibration of the blade, and directly determine the pitch angle of the wind turbine based on the displacement amount of the position marks in the target image. Since the image can objectively and accurately reflect the position change of the pitch bearing, therefore, through the technical solution provided by the embodiments of the present application for quantitatively measuring the pitch angle based on the image, the accuracy of the pitch angle measurement can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a system for measuring the blade pitch angle of a wind turbine generator set provided by an embodiment of the present application;

[0024] Figure 2 is a schematic installation position diagram of an image acquisition device provided by an embodiment of the present application

[0025] Figure 3 is a schematic flow diagram of a method for measuring the blade pitch angle of a wind turbine generator set provided by an embodiment of the present application;

[0026] Figure 4 is a schematic flow diagram of a method for determining pixel positions provided by an embodiment of the present application;

[0027] Figure 5Schematic diagram of the pixel position of the bolt in the embodiment of the present application;

[0028] Figure 6 Schematic structural diagram of the pitch angle measuring device for the blade of a wind turbine provided in the embodiment of the present application;

[0029] Figure 7 Schematic diagram of the gravity torque received by the blade provided in the embodiment of the present application;

[0030] Figure 8 Schematic diagram of the root rotation vibration provided in the embodiment of the present application;

[0031] Figure 9 Schematic diagram of the bolt image provided in the embodiment of the present application. Detailed implementation manners

[0032] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0033] In the present application, terms such as "first", "second", "third", "fourth", etc. (if any) in the description and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0034] In the prior art, it is usually difficult to ensure the accuracy of the measured pitch angle when using a rotary encoder to measure the pitch angle. To solve this technical problem, the embodiment of the present application provides a pitch angle measurement method, which directly measures the pitch angle based on a machine vision algorithm.

[0035] Specifically, in the method for measuring the pitch angle of a wind turbine blade provided in the embodiments of the present application, first, a target image including position marks is obtained by an image acquisition device. The image acquisition device is fixedly installed at a position where the target circumference on the pitch bearing can be photographed. A plurality of position marks are distributed on the target circumference of the pitch bearing, and different identifiers are provided on the surfaces of different position marks. Then, according to the pixel positions of the position marks corresponding in the target image and the pixel positions of the initial position marks corresponding in the initial image photographed by the image acquisition device, the target displacement of the position marks in the target image relative to the initial position marks in the initial image is determined, where the initial position marks correspond to the initial pitch angle. Finally, according to the target displacement, the diameter of the target circumference, and the initial pitch angle, the pitch angle corresponding to the target image is determined.

[0036] The above method realizes the detection of the pitch angle of the wind turbine according to the change of the pixel positions of the position marks in different images photographed by the image acquisition device. Compared with the existing solution for measuring the pitch angle based on a rotary encoder, the technical solution provided in the embodiments of the present application can directly measure the pitch angle based on a machine vision algorithm, thus ensuring the accuracy of the measured pitch angle.

[0037] It should be noted that the method for measuring the pitch angle of a wind turbine blade provided in the embodiments of the present application is generally applied to a measurement system for the pitch angle of a wind turbine blade. Figure 1 FIG. is a schematic structural diagram of a measurement system for the pitch angle of a wind turbine blade provided in the embodiments of the present application. As Figure 1 shown, the pitch angle measurement system includes an image acquisition device 101 and a processor 102. The image acquisition device 101 is communicatively connected to the processor 102. The image acquisition device 101 is fixedly installed at a position where the target circumference of the pitch bearing 103 can be photographed. A plurality of position marks are distributed on the target circumference, and different identifiers are provided on the surfaces of these plurality of position marks. When measuring the pitch angle of the wind turbine, the image acquisition device 101 can photograph the target circumference on the pitch bearing 103 according to a preset photographing period and / or in response to a photographing operation triggered by a user, and obtain an image including the position marks provided on the target circumference.

[0038] Among them, the image acquisition device 101 can be an electronic device with an image photographing function such as a camera, a digital camera, a webcam, and a smart phone. In one example, the image acquisition device 101 can be arranged inside the hub of the wind turbine, and the photographing range is the root bolts fixed on the pitch bearing 103. The root bolts can be inner ring connection bolts or outer ring connection bolts of the pitch bearing.

[0039] As Figure 2, the pitch bearing includes an inner ring 21 and an outer ring 22. The outer ring 22 is sleeved on the outer periphery of the inner ring 21 and can rotate relative to the inner ring 21. The outer ring 22 is fixedly connected to the hub 1 through outer ring connection bolts 7, and the inner ring is fixedly connected to the blade 6 through inner ring connection bolts 8. The pitch drive system drives the inner ring 21 and the blade 6 to rotate a certain angle relative to the outer ring 22 and the hub 1, thereby realizing the pitch of the blade 6.

[0040] In one example, the image acquisition device 101 is arranged on the hub 1, and the shooting direction is towards the end of the inner ring connection bolt 8.

[0041] Furthermore, the image acquisition device 101 can transmit the captured image to the processor 102. After the processor 102 obtains the image transmitted by the image acquisition device 101, it determines the pitch angle corresponding to each image through the pitch angle measurement method provided by the embodiments of the present application. Specifically, the processor 102 can use the image including the position mark transmitted by the image acquisition device 101 as the target image. Then, according to the pixel position corresponding to the position mark in the target image and the pixel position corresponding to the initial position mark in the initial image captured by the image acquisition device 101, it determines the target displacement of the position mark in the target image relative to the initial position mark in the initial image; wherein, the initial image is the image captured by the image acquisition device 101 for the initial position mark, and the initial position mark corresponds to the initial pitch angle of the wind turbine, such as corresponding to the 0° pitch angle of the wind turbine. Furthermore, the processor 102 determines the pitch angle corresponding to the target image according to the above target displacement, the diameter of the target circumference, and the initial pitch angle.

[0042] It should be noted that since a plurality of bolts are evenly distributed on the same circumference of the pitch bearing 103, in practical applications, the bolts on the pitch bearing 103 can be directly used as the above position marks, and different identifiers are marked on the surface of each bolt. Taking a certain model of unit as an example, there are 54 bolts distributed on the pitch bearing. When the pitch bearing rotates from the position of one bolt to the position of another adjacent bolt, the rotation angle is 6.67°.

[0043] It should be noted that usually, in order to facilitate the calculation of the pitch angle corresponding to the image, the image acquisition device 101 can be fixedly installed at a position directly facing the initial position mark. Taking each position mark as a bolt as an example, it is known that when a certain bolt (for example, marked as the 4# bolt) rotates to a certain specific position, the pitch angle of the wind turbine is 0°. Then, the image acquisition device 101 can be fixedly installed at a position directly facing this specific position. When the center point of the 4# bolt coincides with the midline of the image captured by the image acquisition device 101, it can be determined that the pitch angle of the wind turbine is 0°; it should be understood that if the midline of the image coincides with the center point of the 4# bolt, it can be determined that this image is the initial image.

[0044] Ideally, during the operation of a wind turbine generator, if the wind speed remains constant, the pitch angle of the wind turbine generator blades also remains constant. The inventors of the present application found in engineering practice that due to the characteristics of the airfoil, structure, and material of the blade itself, its center of gravity is not located on the central axis of the blade root. The moment generated by gravity exerts a torque on the blade root, and the pitch control system (including the pitch bearing and the pitch drive system) provides rigid support to the blade root part. Under the action of the gravity torque and the support of the pitch control system, there is a small torsional vibration of the blade root around the central axis of the blade root, and the pitch angle of the blade root will have a small change.

[0045] As Figure 7 and Figure 8 shown, the blade is connected to the hub 602 through the pitch bearing 103. Specifically, the blade root 601 of the blade is fixedly connected to the pitch bearing 103 through the blade root bolts. The pitch drive system drives the pitch bearing 103 to rotate around the central axis 705 of the blade root, and the pitch bearing 103 drives the blade to rotate so as to adjust the pitch angle of the blade. Among them, the driving method of the pitch drive system is, for example, a toothed belt drive or a hydraulic drive.

[0046] The center of gravity A of the blade deviates from the central axis 705 of the blade root. The moment generated by gravity exerts a torque M(t) on the blade root. Under the action of the gravity torque and the support of the pitch control system, there is a small torsional vibration of the blade root around the central axis 705 of the blade root, and the pitch angle of the blade root has a torsional amplitude that vibrates reciprocally at a specific frequency.

[0047] In fact, during the process of the image acquisition device photographing the blade root bolts of the pitch bearing, the target bolts have torsional vibrations along with the pitch bearing. As Figure 8 and Figure 9 shown, at the initial pitch position A, the blade root bolts are not stationary, but reciprocate within the amplitude range. In order to obtain the accurate initial pitch position, the embodiment of the present application uses a camera to continuously photograph for a period of time at the initial position A to obtain a sequence of reciprocating swing images of the target bolts, and then identifies the initial position A from the image sequence.

[0048] Specifically, when determining the pixel position corresponding to the initial position marker, when the pitch bearing stops rotating and the image acquisition device 101 is directly facing and photographing the initial position marker, multiple reference initial images collected by the image acquisition device 101 within a first preset time period can be obtained; here, the image acquisition device 101 being directly facing and photographing the initial position marker means that the angular deviation between the initial position marker and the central axis of the image acquisition device 101 is less than a preset angular range. Then, for each reference initial image among the multiple reference initial images, the distance between the initial position marker in the reference initial image and the midline of the reference initial image is determined as the reference distance corresponding to the reference initial image. Furthermore, the reference initial image with the smallest reference distance is selected as the initial image in the above text, that is, the reference initial image with the initial position marker closest to the midline is selected, and the pixel position corresponding to the initial position marker in the initial image is determined, thereby being able to overcome the uncertainty of the pitch angle caused by the root torsion vibration.

[0049] Similarly, for other position markers such as position B, the above method can also be used to determine its pixel position in the target image. Specifically, when the image acquisition device 101 is directly facing and photographing a certain position marker (hereinafter referred to as the target position marker), multiple reference target images collected by the image acquisition device 101 within a second preset time period are obtained. Here, the image acquisition device 101 being directly facing and photographing the target position marker means that the angular deviation between the target position marker and the central axis of the image acquisition device 101 is less than a preset angular range. Then, for each reference target image among the multiple reference target images, the distance between the target position marker in the reference target image and the midline of the reference target image is determined as the reference distance corresponding to the reference target image. Furthermore, the reference target image with the smallest reference distance is selected as the target image in the above text, that is, the reference target image with the target position marker closest to the midline is selected, and the pixel position corresponding to the target position marker in the target image is determined.

[0050] It should be understood that the above first preset time period, second preset time period, and preset angular range can all be set according to actual needs, and the present application does not make specific limitations on them here.

[0051] Next, the method for measuring the pitch angle of the wind turbine blade provided by the present application will be introduced through embodiments.

[0052] See Figure 3 , Figure 3 which is a schematic flowchart of the method for measuring the pitch angle of the wind turbine blade provided by the embodiment of the present application. For the convenience of description, the following embodiments are introduced by taking the processor as the execution subject. As Figure 3 shown, the method for measuring the pitch angle of the wind turbine blade includes the following steps:

[0053] Step 301: Obtain a target image including position marks captured by an image acquisition device; the image acquisition device is fixedly installed at a position capable of capturing a target circumference on the pitch bearing; a plurality of position marks are distributed on the target circumference, and identifiers are provided on the surfaces of the position marks.

[0054] When the processor needs to measure the pitch angle of the wind turbine, the processor can obtain an image including position marks captured by the image acquisition device as the target image. Among them, the image acquisition device is fixedly installed at a position capable of capturing the target circumference on the pitch bearing. A number of position marks are distributed on the target circumference, and different identifiers are provided on the surfaces of different position marks.

[0055] It should be noted that during the same measurement process, the image acquisition device needs to capture each image in this measurement process based on the same set parameters, so as to ensure that based on each image obtained in this measurement process, the actual displacement of the position marks included therein can be accurately determined.

[0056] It should be noted that considering that a plurality of bolts are evenly distributed on the pitch bearing and the positions of these bolts are fixed, that is, when a certain bolt rotates to a certain position, its corresponding pitch angle is also certain. Therefore, the bolts evenly distributed on the pitch bearing can be used as the position marks in the above text. And, in order to distinguish each bolt on the pitch bearing, different identifiers can be provided on the surface of each bolt.

[0057] It should be understood that in addition to using the bolts on the pitch bearing as the position marks in this application, other types of marks can also be set as the position marks in this application. For example, after determining the target circumference of the pitch bearing, several marks with different identifiers can be manually drawn on the target circumference as position marks. No limitation is made on the position marks in this application here.

[0058] In a possible implementation manner, the image acquisition device can capture images according to a preset period and then transmit the captured images to the processor. For example, the image acquisition device can capture an image every 0.5 s and transmit the captured image to the processor in a timely manner. In another possible implementation manner, the image acquisition device can capture an image in response to a user-triggered capture operation and then transmit the captured image to the processor. This application does not make any limitation on the manner in which the processor obtains the target image here.

[0059] Step 302: Determine the target displacement of the position marks in the target image relative to the initial position marks in the initial image according to the pixel positions of the position marks in the target image and the pixel positions of the initial position marks in the initial image captured by the image acquisition device; the initial position marks correspond to the initial pitch angle.

[0060] After the processor obtains the target image captured by the image acquisition device, it can determine the target displacement of the position marker in the target image relative to the initial position marker in the initial image according to the pixel positions corresponding to the position markers in the target image and the pixel positions corresponding to the initial position markers in the initial image captured by the image acquisition device.

[0061] It should be noted that the initial position markers in the above initial image usually correspond to the initial pitch angles. For example, they correspond to the 0° pitch angle of the wind turbine. The initial image includes the initial position markers. Determining the pitch angle corresponding to the target image is essentially determining the displacement amount of the position marker in the target image relative to the position marker in the initial image, and then converting this displacement amount into the corresponding pitch angle. This pitch angle is the angle by which the position marker in the target image rotates relative to the position marker in the initial image.

[0062] In practical applications, the processor can Figure 4 through the process shown, determine the pixel positions corresponding to the position markers in the image captured by the image acquisition device, that is, it can Figure 4 through the process shown determine the pixel positions corresponding to the position markers in the target image and the pixel positions corresponding to the initial position markers in the initial image. Load the image captured by the image acquisition device, then perform binary processing on the image captured by the image acquisition device, and then perform contour recognition and shape recognition on the image obtained after binary processing in sequence to determine the position markers in the image, and finally determine the pixel corresponding to the center point of the position marker as the pixel position corresponding to the position marker.

[0063] Taking the position marker as the bolt on the pitch bearing as an example, the processor can load the image including the bolt captured by the image acquisition device, perform binary processing on the image, and then perform contour recognition and shape recognition on the image after binary processing in sequence to determine the position of the bolt in the image, as shown by 401 and 402 in Figure 5 . Furthermore, determine the pixel corresponding to the center point A of 401 and the pixel corresponding to the center point B of 402 as the pixel positions corresponding to the two bolts in Figure 5 .

[0064] In a possible implementation, if the target image also includes the initial position marker, the processor can directly determine the target displacement of the initial position marker in the target image relative to the initial position marker in the initial image based on the pixel positions corresponding to the initial position markers in the target image and the initial image. Specifically, the processor can determine the pixel offset between the initial position marker in the target image and the initial position marker in the initial image based on the pixel positions corresponding to the initial position markers in the target image and the initial image; then, determine the target displacement based on the pixel offset and the target ratio, where the target ratio is determined based on the actual distance between the two position markers and the pixel offset between the two position markers in the image captured by the image acquisition device.

[0065] The method for determining the target ratio will be introduced below: Assume that the A position marker and the B position marker are used as the reference markers for determining the target ratio. First, the actual distance between the A position marker and the B position marker on the target circumference of the pitch bearing can be determined, and an image captured by the image acquisition device that includes both the A position marker and the B position marker can be obtained. Then, the pixel offset between the A position marker and the B position marker in this image is determined, and further, the ratio of the actual distance between the A position marker and the B position marker to the pixel offset between the A position marker and the B position marker in the image is calculated as the above-mentioned target ratio.

[0066] In the case where the target image also includes the initial position marker, the processor can determine the pixel position a corresponding to the initial position marker in the initial image and the pixel position b corresponding to the initial position marker in the target image, and then calculate the pixel offset RP of the pixel position b relative to the pixel position a. Further, by multiplying the pixel offset RP by the target ratio a, the target displacement RD of the initial position marker in the target image relative to the initial position marker in the initial image can be obtained. The target displacement RD represents the actual rotational distance of the initial position marker between the time of capturing the initial image and the time of capturing the target image.

[0067] It should be noted that in practical applications, in addition to determining the above-mentioned target displacement based on the pixel offset, the above-mentioned target displacement can also be determined based on the offset distance of the position marker in the image. In this case, the ratio used is the ratio of the actual distance between the two position markers in the image to the offset distance between the two position markers in the image.

[0068] In another possible implementation, if the target image does not include the initial position marker, and the image acquisition device captures N (N is an integer greater than or equal to 1) images between the shooting time of the target image and the shooting time of the initial image, and two adjacent images in terms of shooting time among the initial image, the above N images, and the target image include position markers with the same identifier. At this time, the target displacement of the position marker in the target image relative to the initial position marker in the initial image can be determined in the following way: Combine two adjacent images in terms of shooting time among the initial image, the N images, and the target image to obtain multiple reference image groups, and then obtain the displacements corresponding to each of these multiple reference image groups. The displacement corresponding to each reference image group is substantially determined according to the pixel offset between the position markers with the same identifier in this reference image group. Furthermore, superimpose the displacements corresponding to each of these multiple reference image groups to obtain the target displacement of the position marker in the target image relative to the initial position marker in the initial image.

[0069] It should be noted that in practical applications, every time the processor obtains an image transmitted by the image acquisition device, it can determine the relative displacement between the position markers with the same identifier in this image and the previous image transmitted by the image acquisition device. For example, assume that the processor currently obtains the image d transmitted by the image acquisition device. At this time, the processor can determine the displacement of the position marker labeled M in the image d relative to the position marker labeled M in the previous image c transmitted by the image acquisition device.

[0070] The implementation method for specifically determining the relative displacement of the position markers with the same identifier in two adjacent images is the same as the implementation method for determining the displacement of the initial position marker in the target image relative to the initial position marker in the initial image when the target image includes the initial position marker in the above text. For detailed reference, see the relevant description above, and it will not be elaborated here.

[0071] The processor combines two adjacent images in terms of shooting time among the initial image, the N images, and the target image to obtain at least two reference image groups, and then obtains the displacements corresponding to each of these at least two reference image groups. The displacement corresponding to each reference image group is substantially the displacement amount of the position marker with the same identifier in the latter image and the former image in the reference image group. Finally, superimpose the displacements corresponding to each reference image group to obtain the target displacement of the position marker in the target image relative to the initial position marker in the initial image.

[0072] Step 303: Determine the pitch angle corresponding to the target image according to the target displacement, the diameter of the target circle, and the initial pitch angle.

[0073] After the processor determines the target displacement, it can determine the pitch angle corresponding to the target image based on the target displacement, the diameter of the target circumference where the position mark is located, and the initial pitch angle corresponding to the initial position mark. The pitch angle represents the angle by which the position mark in the target image has rotated relative to the initial position mark in the initial image.

[0074] In specific implementation, the processor can calculate the pitch angle corresponding to the above target image based on Equation (1):

[0075] α + arcsin(RD / L) * 2 (1)

[0076] Where, α is the initial pitch angle corresponding to the initial position mark, RD is the target displacement of the position mark in the target image relative to the initial position mark in the initial image, and L is the diameter of the target circumference.

[0077] The above method for measuring the pitch angle of the wind turbine blade is based on the machine vision algorithm to directly measure the pitch angle, effectively ensuring the accuracy of the pitch angle measurement. Specifically, in the method for measuring the pitch angle of the wind turbine blade provided in the embodiments of the present application, first, a target image including a position mark captured by an image acquisition device is obtained. Here, the image acquisition device is fixedly installed at a position where it can capture the target circumference on the pitch bearing. Multiple position marks are distributed on the target circumference, and different identifiers are set on the surfaces of these multiple position marks; then, according to the pixel position corresponding to the position mark in the target image and the pixel position corresponding to the initial position mark in the initial image captured by the image acquisition device, the target displacement of the position mark in the target image relative to the initial position mark is determined. Here, the initial position mark corresponds to the initial pitch angle; furthermore, according to the above target displacement, the diameter of the target circumference, and the initial pitch angle, the pitch angle corresponding to the target image is determined. Compared with the prior art solution for measuring the pitch angle based on a rotary encoder, the technical solution provided in the embodiments of the present application directly determines the pitch angle of the wind turbine based on the displacement amount of the position mark in the target image. Since the image can objectively and accurately reflect the position change of the pitch bearing, therefore, by quantifying and measuring the pitch angle based on the image through the technical solution provided in the embodiments of the present application, the accuracy of the pitch angle measurement can be ensured.

[0078] The embodiments of the present application also provide a device for measuring the pitch angle of a wind turbine blade. Refer to Figure 6 , Figure 6 which is a schematic structural diagram of the device 600 for measuring the pitch angle of the wind turbine blade provided in the embodiments of the present application. As Figure 6 shown, the device includes:

[0079] An image acquisition module 501 is configured to acquire a target image including position markers captured by an image capture device; the image capture device is fixedly installed at a position capable of capturing a target circumference of a pitch bearing; a plurality of position markers are distributed on the target circumference, and identifiers are provided on the surfaces of the position markers.

[0080] A displacement determination module 502 is configured to determine a target displacement of the position marker in the target image relative to the initial position marker in the initial image according to the pixel positions of the position markers corresponding in the target image and the pixel positions of the initial position markers corresponding in the initial image captured by the image capture device; the initial position marker corresponds to an initial pitch angle.

[0081] A pitch angle determination module 503 is configured to determine the pitch angle corresponding to the target image according to the target displacement, the diameter of the target circumference, and the initial pitch angle.

[0082] Optionally, the target image includes the initial position marker, and the displacement determination module 502 is specifically configured to:

[0083] Determine a pixel offset between the initial position marker in the target image and the initial position marker in the initial image according to the pixel positions of the initial position markers corresponding in the target image and the pixel positions of the initial position markers corresponding in the initial image;

[0084] Determine the target displacement according to the pixel offset and a target ratio; the target ratio is determined according to the actual distance between two position markers and the pixel offset between the two position markers in the image captured by the image capture device.

[0085] Optionally, the target image does not include the initial position marker, the image capture device captures N images between the shooting time of the target image and the shooting time of the initial image, and two adjacent images in terms of shooting time among the initial image, the N images, and the target image include position markers with the same identifier; N is an integer greater than or equal to 1; then the displacement determination module 502 is specifically configured to:

[0086] Combine two adjacent images in terms of shooting time among the initial image, the N images, and the target image to obtain a plurality of reference image groups;

[0087] Obtain the displacements corresponding to the respective plurality of reference image groups; the displacement corresponding to a reference image group is determined according to the pixel offset between the position markers with the same identifier in the reference image group;

[0088] Superimpose the displacements corresponding to the respective plurality of reference image groups to obtain the target displacement.

[0089] Optionally, the device further includes:

[0090] An initial position marker determination module, configured to, when the pitch bearing stops rotating and the image acquisition device is facing and photographing the initial position marker, obtain multiple reference initial images acquired by the image acquisition device within a first preset time period; for each reference initial image among the multiple reference initial images, determine the distance between the initial position marker in the reference initial image and the midline of the reference initial image as the reference distance corresponding to the reference initial image; determine the reference initial image with the smallest reference distance as the initial image, and determine the pixel position corresponding to the initial position marker in the initial image;

[0091] A target position marker determination module, configured to, when the image acquisition device is facing and photographing the position marker, obtain multiple reference target images acquired by the image acquisition device within a second preset time period; for each reference target image among the multiple reference target images, determine the distance between the position marker in the reference target image and the midline of the reference target image as the reference distance corresponding to the reference target image; determine the reference target image with the smallest reference distance as the target image, and determine the pixel position corresponding to the position marker in the target image.

[0092] Optionally, the device further includes:

[0093] A binarization processing module, configured to perform binarization processing on the image photographed by the image acquisition device;

[0094] A position marker determination module, configured to perform contour recognition and shape recognition on the binarized image in sequence to determine the position marker;

[0095] A pixel position determination module, configured to determine the pixel at the center point of the position marker as the pixel position corresponding to the position marker.

[0096] Optionally, the pitch angle determination module 503 is specifically configured to:

[0097] Calculate the pitch angle corresponding to the target image through formula (1):

[0098] α + arcsin(RD / L) * 2 (1)

[0099] wherein, α is the initial pitch angle, RD is the target displacement, and L is the diameter of the target circumference.

[0100] Optionally, the position marker is bolts evenly distributed on the pitch bearing, and different bolts are provided with different identifiers.

[0101] The above-mentioned measuring device for the blade pitch angle of a wind turbine realizes the direct measurement of the pitch angle based on a machine vision algorithm, effectively ensuring the accuracy of the pitch angle measurement. Specifically, in the measuring device for the blade pitch angle of a wind turbine provided in the embodiments of the present application, first, a target image including position marks captured by an image acquisition device is obtained. Here, the image acquisition device is fixedly installed at a position where the target circumference on the pitch bearing can be photographed. A plurality of position marks are distributed on the target circumference, and different identifiers are provided on the surfaces of these plurality of position marks; then, according to the pixel positions corresponding to the position marks in the target image and the pixel positions corresponding to the initial position marks in the initial image captured by the image acquisition device, the target displacement of the position marks in the target image relative to the initial position marks is determined. Here, the initial position marks correspond to the initial pitch angle; furthermore, according to the above-mentioned target displacement, the diameter of the target circumference, and the initial pitch angle, the pitch angle corresponding to the target image is determined. The device provided in the embodiments of the present application directly determines the pitch angle of the wind turbine based on the displacement amount of the position marks in the target image. Since the image can objectively and accurately reflect the position change of the pitch bearing, therefore, by quantifying the measurement of the pitch angle based on the image by the device provided in the embodiments of the present application, the accuracy of the pitch angle measurement can be ensured.

[0102] The embodiments of the present application also provide a computer-readable storage medium, which is used to store a computer program, and the computer program is used to execute the method for measuring the blade pitch angle of a wind turbine introduced in the above method embodiments.

[0103] The embodiments of the present application also provide a computer program product including instructions, which, when running on a computer, cause the computer to execute the method for measuring the blade pitch angle of a wind turbine introduced in the above method embodiments.

[0104] Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the above-described systems, devices, and units can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0105] In several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be in an electrical, mechanical, or other form.

[0106] The unit described as a separation component may or may not be physically separated. The component shown as a unit may or may not be a physical unit, that is, it may be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0107] In addition, each functional unit in various embodiments of the present application may be integrated in a processing unit, may exist separately as individual physical units, or two or more units may be integrated in one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0108] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present application. The aforementioned storage medium includes: USB flash drives, mobile hard disks, read-only memories (English full name: Read-Only Memory, English abbreviation: ROM), random access memories (English full name: Random Access Memory, English abbreviation: RAM), magnetic disks or optical discs and other various media that can store computer programs.

[0109] It should be understood that in the present application, "at least one (item)" means one or more, and "multiple" means two or more. "And / or" is used to describe the association relationship of associated objects and indicates that three relationships can exist. For example, "A and / or B" can represent: only A exists, only B exists, and both A and B exist at the same time. Among them, A and B can be singular or plural. The character " / " generally represents that the associated objects before and after are in an "or" relationship. "At least one (one)" or its similar expression below refers to any combination of these items, including any combination of single item (one) or plural items (ones). For example, at least one (one) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0110] As described above, the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.

Claims

1. A method for measuring the pitch angle of a wind turbine blade, characterized in that, The method includes: Obtaining a target image captured by an image acquisition device, the image acquisition device being fixedly installed at a position capable of capturing a target circumference on a pitch bearing, a plurality of position markers being distributed on the target circumference, and an identifier being provided on the surface of the position markers; the target image is selected from multiple reference target images acquired by the image acquisition device within a second preset time period, the target image being the reference target image corresponding to the smallest corresponding reference distance, the reference distance corresponding to the reference target image being the distance between the position marker in the reference target image and the midline of the reference target image; Determining a target displacement of the position marker in the target image relative to the initial position marker in the initial image according to the pixel position corresponding to the position marker in the target image and the pixel position corresponding to the initial position marker in the initial image captured by the image acquisition device, the initial position marker corresponding to an initial pitch angle; Determining the pitch angle corresponding to the target image according to the target displacement, the diameter of the target circumference, and the initial pitch angle; The target image does not include the initial position marker, and the image acquisition device captures N images between the shooting time of the target image and the shooting time of the initial image. Two adjacent images in terms of shooting time among the initial image, the N images, and the target image include position markers with the same identifier; N is an integer greater than or equal to 1; then the determining the target displacement of the position marker in the target image relative to the initial position marker in the initial image according to the pixel position corresponding to the position marker in the target image and the pixel position corresponding to the initial position marker in the initial image includes: Combining two adjacent images in terms of shooting time among the initial image, the N images, and the target image to obtain multiple reference image groups; Obtaining the displacement corresponding to each of the multiple reference image groups; the displacement corresponding to the reference image group is determined according to the pixel offset between the position markers with the same identifier in the reference image group and a target ratio, the target ratio being determined according to the actual distance between two position markers and the pixel offset between the two position markers in the image captured by the image acquisition device; Superimposing the displacements corresponding to each of the multiple reference image groups to obtain the target displacement.

2. The method according to claim 1, wherein If the target image includes the initial position marker, then the determining the target displacement of the position marker in the target image relative to the initial position marker in the initial image according to the pixel position corresponding to the position marker in the target image and the pixel position corresponding to the initial position marker in the initial image captured by the image acquisition device includes: Determining the pixel offset between the initial position marker in the target image and the initial position marker in the initial image according to the pixel position corresponding to the initial position marker in the target image and the pixel position corresponding to the initial position marker in the initial image; Determine the target displacement according to the pixel offset and the target ratio; the target ratio is determined according to the actual distance between two position markers and the pixel offset between the two position markers in the image captured by the image acquisition device.

3. The method according to claim 1 or 2, characterized in that, Determine the pixel position corresponding to the initial position marker in the initial image in the following manner: When the pitch bearing stops rotating and the image acquisition device is directly facing the initial position marker for shooting, obtain multiple reference initial images acquired by the image acquisition device within a first preset time period; For each reference initial image among the multiple reference initial images, determine the distance between the initial position marker in the reference initial image and the midline of the reference initial image as the reference distance corresponding to the reference initial image; Determine the reference initial image with the smallest reference distance as the initial image, and determine the pixel position corresponding to the initial position marker in the initial image.

4. The method according to claim 1, wherein Determine the pixel position corresponding to the position marker in the image captured by the image acquisition device in the following manner: Perform binarization processing on the image captured by the image acquisition device; Based on the binarized image, perform contour recognition and shape recognition in sequence to determine the position marker; Determine the pixel at the center point of the position marker as the pixel position corresponding to the position marker.

5. The method according to claim 1, wherein The position marker is a bolt evenly distributed on the pitch bearing, and an identifier is provided on the surface of the bolt.

6. A measuring device for the blade pitch angle of a wind turbine generator, characterized in that, The device includes: An image acquisition module, configured to acquire a target image including a position marker captured by an image acquisition device. The image acquisition device is fixedly installed at a position capable of capturing the target circumference of the pitch bearing, and a plurality of position markers are distributed on the target circumference, and an identifier is provided on the surface of the position marker; the target image is selected from multiple reference target images acquired by the image acquisition device within a second preset time period, and the target image is the reference target image corresponding to the smallest reference distance. The reference distance corresponding to the reference target image is the distance between the position marker in the reference target image and the midline of the reference target image; A displacement determination module, configured to determine the target displacement of the position marker in the target image relative to the initial position marker according to the pixel position corresponding to the position marker in the target image and the pixel position corresponding to the initial position marker in the initial image captured by the image acquisition device; the initial position marker corresponds to the initial pitch angle; A pitch angle determination module, configured to determine the pitch angle corresponding to the target image according to the target displacement, the diameter of the target circumference, and the initial pitch angle; The target image does not include the initial position marker. The image acquisition device captures N images between the shooting time of the target image and the shooting time of the initial image. Two adjacent images in terms of shooting time among the initial image, the N images, and the target image include position markers with the same identifier; N is an integer greater than or equal to 1; then the displacement determination module is specifically configured to: Combine two adjacent images in terms of shooting time among the initial image, the N images, and the target image to obtain a plurality of reference image groups; Obtain the displacement corresponding to each of the plurality of reference image groups; the displacement corresponding to the reference image group is determined according to the pixel offset between position markers with the same identifier in the reference image group and the target ratio, and the target ratio is determined according to the actual distance between two position markers and the pixel offset between the two position markers in the image captured by the image acquisition device; Superimpose the displacements corresponding to each of the plurality of reference image groups to obtain the target displacement.

7. A blade pitch angle measurement system for a wind turbine generator, characterized in that, The system includes: an image acquisition device and a processor, and the image acquisition device is communicatively connected to the processor; The image acquisition device is fixedly installed at a position capable of shooting the target circumference of the pitch bearing, and a plurality of position markers are distributed on the target circumference, and identifiers are provided on the surface of the position markers; The image acquisition device is configured to shoot the position markers provided on the target circumference; The processor is configured to execute the method for measuring the blade pitch angle of a wind turbine generator set according to any one of claims 1 to 5.

8. The system according to claim 7, wherein The image acquisition device is arranged inside the hub of the wind turbine generator set and shoots the root bolts fixed on the pitch bearing.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a computer program, and the computer program is used to execute the method for measuring the blade pitch angle of a wind turbine generator set according to any one of claims 1 to 5.

10. A computer product including instructions, characterized in that, When it runs on a computer, it causes the computer to execute the method for measuring the blade pitch angle of a wind turbine generator set according to any one of the above claims 1 to 5.

Images