A wind turbine blade clearance detection device and detection method

Abstract

The present invention discloses a clearance detection device and a detection method for a wind turbine blade. The device is installed at a preset position in the nacelle of the wind turbine. The device includes an L-shaped bracket (1) and a clearance detection box body (2). The vertical section of the L-shaped bracket (1) is connected to the nacelle (3) of the wind turbine, and the horizontal section is installed with the clearance detection box body (2). An IMU sensor (6), a lidar (7), and an industrial camera (8) are arranged in the clearance detection box body (2). Among them, the IMU sensor (6) collects the attitude data of the wind turbine blade (4), the lidar (7) collects the point cloud data of the wind turbine blade (4), and the industrial camera (8) collects the image data of the wind turbine blade (4). The attitude data, point cloud data, and image data are all input into the upper computer. When the upper computer detects that the wind turbine blade (4) enters the non-safe clearance area, the operation of the wind turbine is stopped.

Description

Technical Field

[0001] The present invention relates to the field of fan safety monitoring, and particularly to a fan blade clearance detection device and a detection method. Background Art

[0002] A fan is a machine that relies on the input mechanical energy to increase the gas pressure and pump the gas. It is a driven fluid machine. It is mainly used for power generation. When the wind drives the generator armature to rotate, since there is residual magnetism in the magnetic pole iron core of the generator, the armature coil cuts the magnetic force lines in the magnetic field. According to the principle of electromagnetic induction, current is generated by magnetic induction and output through the carbon brush.

[0003] The tip-tower clearance refers to the minimum geometric distance between the tip of the blade and the tower when the blade of the wind turbine hub rotates and sweeps over the tower. The shape of the rotating surface formed by the blade rotating under the action of the wind force often changes with the change of the wind force load. In order to avoid the movement interference between the blade and the tower, it is necessary to calculate the tip-tower clearance distance under various working conditions through simulation during the design to ensure the safe operation of the fan.

[0004] The current products on the market mainly calculate the blade-tower clearance through high-speed photography and image post-processing analysis. The main defects are as follows: complex data post-processing analysis is required, and the clearance measurement value cannot be calculated in real time; the clearance distance is obtained through image processing, and the measurement uncertainty is greatly affected by the relative angle between the shooting position and the fan to be measured; during the operation of the fan, it is necessary to continuously adjust the shooting position according to different yaw positions, and it is difficult to ensure data consistency; data cannot be measured in bad weather and at night, and it is difficult to synchronize with the fan data. The tip-tower clearance measurement cannot directly measure and calculate the tip-tower clearance under various wind conditions in real time. In addition to the difficulty in achieving data synchronization, it is also difficult for the traditional method to achieve the expected effect and is relatively complex to implement for the clearance distance detection under complex mountain terrains.

[0005] Currently, there is a prior art method for automatically monitoring the clearance of a wind turbine blade based on multiple laser heads. A point is determined at a safe clearance value from the outer wall of the wind turbine tower on the ground. Then, a laser rangefinder is installed on the nacelle of the wind turbine. The laser rangefinder is designed with multiple laser heads. The beam of one laser head hits the lower tip of the blade to trigger the critical position of the safe clearance, and the beams of the remaining laser heads hit the area near the lower tip of the blade. The distance measured by the laser rangefinder is the distance between it and the lower tip of the blade. When the control system of the wind turbine monitors the above changes, it will make a judgment, alarm and stop the machine, and the blade will stop rotating to ensure the safe operation of the wind turbine. Under the action of multiple laser heads, when the blade enters the non-safe clearance area, multiple points in the area near the lower tip can be monitored. These multiple points form a plane, that is, when the blade sweeps through the monitoring position, a plane can be monitored. By monitoring this plane, false alarms of clearance caused by non-blade behaviors can be avoided. The disadvantages of the prior art are that it requires measurement on the ground and multiple laser heads. Each time a wind turbine is measured, it is necessary to calculate and determine the azimuth of the clearance detection device from the wind turbine, and it is also affected by the complex surface conditions. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and propose a device and method for detecting the clearance of a wind turbine blade.

[0007] To achieve the above purpose, the present invention proposes a device for detecting the clearance of a wind turbine blade, which is installed at a preset position in the nacelle of the wind turbine. The device includes an L-shaped bracket and a clearance detection box body; the vertical section of the L-shaped bracket is connected to the nacelle of the wind turbine, and the horizontal section is installed with the clearance detection box body. An IMU sensor, a lidar and an industrial camera are arranged in the clearance detection box body; among them, the IMU sensor collects the attitude data of the wind turbine blade, the lidar collects the point cloud data of the wind turbine blade, and the industrial camera collects the image data of the wind turbine blade; the attitude data, point cloud data and image data are all input into the upper computer. When the upper computer detects that the wind turbine blade enters the non-safe clearance area, the wind turbine is stopped.

[0008] As an improvement of the above device, the horizontal section of the L-shaped bracket is a telescopic rod, and a rotating shaft is arranged at the connection with the clearance detection box body. The viewing angle of the clearance detection box body is adjusted by adjusting the rotating shaft, and the viewing angle range is 0-180 degrees.

[0009] As an improvement of the above device, a rotating shaft is arranged between the vertical section and the horizontal section of the L-shaped bracket, and the height of the clearance detection box body is adjusted by adjusting the rotating shaft.

[0010] As an improvement of the above device, the lidar is a wide-angle radar, and two prisms with different angles are arranged in the radar so that the field of view angle of the radar covers both the wind turbine blade and the wind turbine tower barrel at the same time.

[0011] As an improvement of the above device, the clearance detection box body further includes an IMU interface, a LAN1 interface, a LAN2 interface, and a power interface, where,

[0012] Attitude data is uploaded to the host computer through the IMU interface, and point cloud data and image data are uploaded to the host computer through the LAN1 interface. The device communicates with the host computer through the LAN2 interface; power for the device to operate is obtained through the power interface.

[0013] A method for detecting the clearance of a wind turbine blade, implemented based on the above device, the method includes:

[0014] Obtain the attitude data, point cloud data, and image data collected by the wind turbine blade clearance detection device;

[0015] Perform three-dimensional reconstruction based on the point cloud data and the image data;

[0016] Identify the wind turbine blade through semantic analysis;

[0017] Calculate the clearance distance between the wind turbine blade and the wind turbine tower barrel in combination with the attitude data;

[0018] When the clearance distance is less than the set threshold, it is determined that the wind turbine blade enters the non-safe clearance area, and then a control command is issued to stop the operation of the wind turbine.

[0019] As an improvement of the above method, the performing three-dimensional reconstruction based on the point cloud data and the image data specifically includes:

[0020] Perform data filtering on the collected point cloud data to obtain effective point cloud data;

[0021] Extract features from the effective point cloud data based on the morphological feature point extraction algorithm;

[0022] Perform inertial navigation solution on the attitude data to obtain the displacement, attitude, and speed of the wind turbine blade;

[0023] Perform three-dimensional reconstruction in combination with the image data based on the extracted features to obtain a three-dimensional model.

[0024] As an improvement of the above method, the data filtering specifically includes:

[0025] Remove the noise points caused by a small amount of precipitation and dust by radius filtering;

[0026] Remove the point cloud noise of the wind turbine tower and the ground within the effective area range;

[0027] Extract the characteristic values of clouds, rain, and fog, filter the corresponding point clouds, and obtain the denoised effective point cloud data.

[0028] As an improvement of the above method, the net clearance distance between the wind turbine blade and the wind turbine tower is calculated by combining the attitude data; specifically, it includes:

[0029] Based on the three-dimensional reconstruction, the three-dimensional point coordinates of the wind turbine blade are obtained, and the vertical distances from different position points of the wind turbine blade to the outer wall of the wind turbine tower are calculated by combining the attitude data;

[0030] By finding the ground plane information reference, the vertical direction is obtained, the wind turbine blade data is corrected to the vertical direction, reference position points are obtained at regular intervals along the wind turbine blade direction, the overall bending shape of the wind turbine blade is obtained, and then the deformation data of the wind turbine blade is obtained, so as to obtain the net clearance distance of each reference position point of the wind turbine blade.

[0031] Compared with the prior art, the advantages of the present invention are as follows:

[0032] 1. The net clearance detection device for the wind turbine blade of the present invention is installed in the wind turbine nacelle, overcoming the influence of the surface morphology and environment on the traditional wind turbine blade detection device due to being placed on the ground;

[0033] 2. The number of scanning point clouds of the net clearance detection device for the wind turbine blade of the present invention reaches 240,000, with a wide data acquisition range, high acquisition frequency, accurate acquisition position, and the accuracy will not be reduced due to blade deformation;

[0034] 3. The detection method of the present invention obtains the real-time deformation curve of the entire blade through data analysis, and then calculates the net clearance distance between the wind turbine blade and the wind turbine tower, so as to judge whether the wind turbine is in a safe operating state, with the advantages of good real-time performance and high automation degree. Description of the Drawings

[0035] Figure 1 is the installation schematic diagram of the net clearance detection device for the wind turbine blade of the present invention;

[0036] Figure 2 is the front view of the net clearance detection device for the wind turbine blade of the present invention;

[0037] Figure 3 is the rear view of the net clearance detection device for the wind turbine blade of the present invention;

[0038] Figure 4 is the schematic diagram of calculating the net clearance value by using the method of the present invention;

[0039] Figure 5 is the schematic diagram of the deformation curve of the wind turbine blade obtained by using the method of the present invention;

[0040] Figure 6 is the schematic diagram of the net clearance value curves at different positions of the wind turbine blade obtained by using the method of the present invention.

[0041] Reference Signs

[0042] 1. L-shaped bracket 2. Clearance detection box

[0043] 3. Wind turbine nacelle 4. Wind turbine blade

[0044] 5. Wind turbine tower 6. IMU sensor

[0045] 7. LiDAR 8. Industrial camera

[0046] 9. IMU interface 10. LAN2 interface

[0047] 11. LAN1 interface 12. Power interface Detailed implementation method

[0048] The technical solution of the present invention will be described in detail below in conjunction with the drawings and embodiments.

[0049] Embodiment 1

[0050] As Figure 1 shown, it is an installation schematic diagram of the wind turbine blade clearance detection device. The wind turbine blade clearance detection device is installed at a preset position in the wind turbine nacelle.

[0051] As Figure 2 shown, the wind turbine blade clearance detection device is installed at a preset position in the wind turbine nacelle, including an L-shaped bracket 1 and a clearance detection box 2; the vertical section of the L-shaped bracket 1 is connected to the wind turbine nacelle 3 of the wind turbine, and the horizontal section installs the clearance detection box 2, and try to keep it horizontal during installation. The clearance detection box 2 is provided with an IMU sensor 6, a LiDAR 7 and an industrial camera 8; among them, the IMU sensor 6 collects the attitude data of the wind turbine blade 4 through the IMU interface 9, the LiDAR 7 collects the point cloud data of the wind turbine blade 4 and the industrial camera 8 collects the image data of the wind turbine blade 4 through the LAN1 interface 11, and inputs them into the clearance detection module of the upper computer. When the clearance detection module detects and identifies that the wind turbine blade 4 enters the non-safe clearance area, it notifies the wind turbine to stop working.

[0052] The horizontal section of the L-shaped bracket 1 is a telescopic rod, and a rotating shaft is provided at the connection with the clearance detection box 2, and the viewing angle of the clearance detection box 2 is adjusted by adjusting the rotating shaft, and the viewing angle range is 0-180 degrees; a rotating shaft is provided between the vertical section and the horizontal section of the L-shaped bracket 1, and the height of the clearance detection box 2 is adjusted by adjusting the rotating shaft.

[0053] The LiDAR 7 is a customized wide-angle radar to achieve large-angle scanning coverage. The radar adopts a unique prism scanning method, using two prisms to emit the radar from different directions, so that the field of view angle of the radar covers both the wind turbine blade 4 and the wind turbine tower 5 at the same time.

[0054] As Figure 3As shown in the figure, the clearance detection box body 2 includes an IMU interface 9, a LAN1 interface 11, a LAN2 interface 10, and a power interface 12. Among them,

[0055] The attitude data is uploaded to the host computer through the IMU interface 9, and the point cloud data and image data are uploaded to the host computer through the LAN1 interface 11. The device communicates with the host computer through the LAN2 interface 10; the power for the device to work is obtained through the power interface 12.

[0056] This device is installed on the fan nacelle, and the installation position is determined, without the need for multiple repeated calculations of the installation position as in the prior art. It can cope with complex terrains and collect data in real time. When the fan blade enters the non-safe clearance area, the fan stops working to ensure the safety of the fan operation.

[0057] Embodiment 2

[0058] Embodiment 2 of the present invention proposes a method for detecting the clearance of a fan blade, which is implemented based on the detection device of Embodiment 1.

[0059] The specific principle is as follows: The beam of the lidar hits the critical position of the lower tip of the blade to trigger the safe clearance. The viewing angle is adjusted through the rotating shaft at the probe end, so that the angle adjustment range reaches 0 - 180 degrees. When automatically monitoring the blade clearance, during the operation of the fan, if the blade is operating in the safe clearance area, the distance measured by the laser rangefinder is the distance between it and the position where the ground laser hits. If the blade enters the non-safe clearance area due to the action of strong wind, the laser will hit the blade, and the distance measured by the laser rangefinder will change. At this time, the distance measured by the laser rangefinder is the distance between it and the lower tip of the blade. The control system of the fan monitors the above changes and will make a judgment, alarm and stop the machine, and the blade stops rotating to ensure the safety of the fan operation. Three-dimensional modeling data is obtained through laser scanning, so that when the blade enters the non-safe clearance area, multiple points in the area near the lower tip can be monitored. These multiple points form a surface, that is, a surface can be monitored when the blade sweeps through the monitoring position. By monitoring this surface, false alarms of clearance caused by non-blade behaviors can be avoided, thereby improving the accuracy of clearance alarms.

[0060] The specific steps of the clearance detection method are as follows:

[0061] (1) Simulation calculation

[0062] A mathematical model is established through simulation experiments, system simulation is carried out, and the simulation value of setting the safe clearance area is obtained, that is, the threshold value when the blade is in the safe clearance area.

[0063] (2) Data acquisition

[0064] The wind turbine is fixed at the top of the tower barrel which serves as a vertical support. The front end of the wind turbine has three rotating blades, and this detection device is installed at a set distance in the nacelle. According to the perspective requirement, the stroke of the telescopic rod is adjusted, and the probe can extend out of the nacelle. The viewing angle can also be adjusted through the rotating shaft at the probe end, so that the angle adjustment range reaches 0 - 180 degrees. After adjusting the viewing angle, the IMU sensor, lidar, and industrial camera scan the target object. The attitude data of the wind turbine blades collected by the IMU sensor is uploaded to the host computer through the IMU interface; the point cloud data of the wind turbine blades collected by the lidar and the image data collected by the industrial camera are uploaded to the host computer through the LAN1 interface. Attitude data: Utilize the IMU of the wind turbine clearance detection device and transmit the data to the computer terminal through the IMU interface.

[0065] (3) 3D reconstruction

[0066] 1) Data filtering

[0067] Perform data filtering on the collected point cloud data, specifically including: radius filtering to remove noise points caused by a small amount of precipitation and dust; within the effective area range, remove the noise points of the wind turbine tower and the ground point cloud; extract the characteristic values of clouds, rain, and fog and filter the corresponding point cloud; after denoising, obtain the effective point cloud. Among them, the features mainly include feature points, feature lines, and regions. Taking feature points as the matching primitives, the form of feature point extraction is closely related to the matching strategy used. Select a feature point extraction algorithm based on morphology and improve the registration algorithm to improve the reconstruction and restoration degree for complex scenes.

[0068] 2) Inertial navigation solution

[0069] Based on the carrier acceleration measured by the accelerometer and the angular velocity of the carrier relative to the navigation coordinate system measured by the gyroscope of the IMU sensor, perform inertial navigation solution on the position, attitude, and velocity of the carrier.

[0070] 3) Model reconstruction

[0071] After completing camera calibration, preprocessing and matching of three-dimensional object stereo images, and obtaining the three-dimensional coordinates of spatial points, the three-dimensional scene information can be restored. Since the accuracy of 3D reconstruction is affected by factors such as matching accuracy and the internal and external parameter errors of the camera, it is necessary to do a good job in the previous steps first, so that the accuracy of each link is high and the error is small, so as to design a relatively accurate stereo vision system.

[0072] The automatic reconstruction of the dense point cloud of the three-dimensional scene by fusing the laser point cloud is conducive to obtaining the scene structure. The feature extraction and matching algorithm of the image is used to track the feature points of the image by the algorithm and extract dense and robust feature points. This method projects light information to the target scene or object by using a laser scanning device, and calculates and processes the received return information, thereby obtaining the target distance and reconstructing the three-dimensional model of the object.

[0073] (4) Wind turbine blade recognition

[0074] Through the automatic real-time analysis of data by the algorithm, the acquisition of real-time data and its automatic parsing, the semantic analysis of core objects, and the automatic extraction of wind turbine blade data are realized. By developing a real-time algorithm parsing program based on Linux, the data of lidar can be parsed in real time, and basic object semantic analysis can be achieved, mainly including the semantic judgment of the tower barrel, blades, and ground. Based on the three-dimensional reconstruction of radar scanning, the positional relationship when the blade sweeps across the tower barrel is restored in real time.

[0075] (5) Calculate the clearance value

[0076] The three-dimensional point coordinates of the wind turbine blade are obtained through three-dimensional modeling, and the relative displacement of the automatic monitoring device of the wind turbine blade clearance is obtained by adding IMU inertial navigation. The point cloud data scanned at different angles is integrated through the relative displacement to form a complete three-dimensional model of the three-dimensional wind blade and the upright support column of the wind turbine. Calculate the vertical distance from each position point of the entire blade to the column. Using the obtained blade data, and then through finding information references such as the ground plane to obtain the vertical direction, the data is corrected to the vertical direction, the blade data is analyzed, and reference position points (using the average position) of the blade part are obtained at regular intervals along the blade direction. By obtaining the average position, the bending shape of the overall blade is obtained, and then the deformation data of the blade is obtained, so as to infer the clearance distance of the blade, and thus make a timely warning. By extracting the key points of the lower half of the blade and calculating the clearance value, the blade deformation curve is obtained.

[0077] The corresponding point cloud data of the wind turbine blade is detected through semantic analysis and corrected according to the ground, and then information such as the height of the wind turbine blade from the bottom surface is obtained. Select the positions at h0 meters and h1 meters from the ground surface where the solar wind turbine is installed (including the entire wind turbine blade). As Figure 4 shown, reference points are selected every 5m between h0 and h1. Cross-section calculations are performed on the blade at the reference point positions of the blade, and a cross-section is extracted between two reference points, and the distance values d1, d2,..., dn from the cross-section to the vertical line of the sensing device are output. As Figure 5 shown, it is a schematic diagram of the wind turbine blade deformation curve; as Figure 6 shown, it is a schematic diagram of the clearance value curve at different positions of the wind turbine blade.

[0078] 6) Data analysis and warning

[0079] By performing real-time analysis on the data of the wind turbine blades, the deformation degree of the wind turbine is judged based on the simulation experiment data and the position trend of the wind turbine blades. When the average value of the distance from the position of the blade reference point to the wind turbine column is less than the set value (i.e., d1 < L1, d2 < L2,.....dn < Ln, where L1, L2,...., Ln are obtained through simulation calculations and represent the clearance safety distance, i.e., the threshold), it is determined that the clearance safety distance fails, and the system issues an alarm. There will be a continuously flashing red warning light on the system interface, and the detection device will be notified to stop the operation of the wind turbine. If the distance is greater than the set value H, it is considered that the clearance safety distance is effective, and the blades of the wind turbine are operating within the requirements of the clearance safety distance. There will be a green light remaining bright on the system interface, indicating that the wind turbine is operating normally.

[0080] Wind power generation is a new energy with great potential, meeting the requirements of government advocacy and human development. Pollution-free energy will be the main trend of future development. The present patent invention is a real-time detection device for the clearance of wind turbine blades, which can well monitor whether the wind turbine blades are operating normally. The real-time, automated, and intelligent detection device can help humans better manage a large number of wind turbines.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A clearance detection device for a fan blade, which is installed at a preset position in the nacelle of a fan, and is characterized in that, The device includes an L-shaped bracket (1) and a clearance detection box body (2); the vertical section of the L-shaped bracket (1) is connected to the fan nacelle (3) of the fan, and the horizontal section is installed with the clearance detection box body (2). An IMU sensor (6), a lidar (7), and an industrial camera (8) are arranged inside the clearance detection box body (2); among them, the IMU sensor (6) collects the attitude data of the fan blade (4), the lidar (7) collects the point cloud data of the fan blade (4), and the industrial camera (8) collects the image data of the fan blade (4); the attitude data, point cloud data, and image data are all input into the upper computer. When the upper computer detects that the fan blade (4) enters the non-safe clearance area, the fan is stopped from working; The detection method based on the fan blade clearance detection device includes: Obtaining the attitude data, point cloud data, and image data collected by the fan blade clearance detection device; Performing three-dimensional reconstruction based on the point cloud data and image data; Identifying the fan blade through semantic analysis; Calculating the clearance distance between the fan blade and the fan tower barrel in combination with the attitude data; When the clearance distance is less than the set threshold, it is determined that the fan blade enters the non-safe clearance area, and a control command is issued to stop the fan from working.

2. The fan blade clearance detection device according to claim 1, characterized in that, The horizontal section of the L-shaped bracket (1) is a telescopic rod, and a rotating shaft is arranged at the connection with the clearance detection box body (2). The viewing angle of the clearance detection box body (2) is adjusted by adjusting the rotating shaft, and the viewing angle range is 0-180 degrees.

3. The fan blade clearance detection device according to claim 1, characterized in that A rotating shaft is arranged between the vertical section and the horizontal section of the L-shaped bracket (1), and the height of the clearance detection box body (2) is adjusted by adjusting the rotating shaft.

4. The clearance detection device for a fan blade according to claim 1, characterized in that, The lidar (7) is a wide-angle radar, and two prisms with different angles are arranged inside the radar so that the field of view angle of the radar covers both the fan blade (4) and the fan tower barrel (5) at the same time.

5. The fan blade clearance detection device according to claim 1, wherein, The clearance detection box body (2) further includes an IMU interface (9), a LAN1 interface (11), a LAN2 interface (10), and a power interface (12), where The attitude data is uploaded to the upper computer through the IMU interface (9), and the point cloud data and image data are uploaded to the upper computer through the LAN1 interface (11). The device communicates with the upper computer through the LAN2 interface (10); the power for the device to work is obtained through the power interface (12).

6. The method for detecting the clearance of a fan blade according to claim 1, wherein The performing three-dimensional reconstruction based on the point cloud data and image data; specifically includes: Performing data filtering on the collected point cloud data to obtain effective point cloud data; Performing feature extraction on the effective point cloud data based on the feature point extraction algorithm based on morphology; Performing inertial navigation solution on the attitude data to obtain the displacement, attitude, and speed of the fan blade; Performing three-dimensional reconstruction based on the extracted features and combining the image data to obtain a three-dimensional model.

7. The method for detecting the clearance of a fan blade according to claim 6, characterized in that, The data filtering specifically includes: Removing the noise points brought by a small amount of precipitation and dust by radius filtering; Removing the point cloud noise of the fan tower and the ground within the effective area range; Extracting the eigenvalue of cloud, rain, and fog, filtering the corresponding point cloud, and obtaining the denoised effective point cloud data.

8. The method for detecting the clearance of a fan blade according to claim 1, wherein The calculating the clearance distance between the fan blade and the fan tower barrel in combination with the attitude data; specifically includes: Based on the three-dimensional reconstruction, obtaining the three-dimensional point coordinates of the fan blade, and calculating the vertical distance from different position points of the fan blade to the outer wall of the fan tower barrel in combination with the attitude data; By finding the ground plane information reference, the vertical direction is obtained, the fan blade data is corrected to the vertical direction, reference position points are obtained at regular intervals along the fan blade direction, the overall bending shape of the fan blade is obtained, and then the deformation data of the fan blade is obtained, so as to obtain the clearance distance of each reference position point of the fan blade.

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