Wind turbine blade deformation monitoring device and method based on light reflection and refraction

Abstract

The application discloses a wind turbine blade deformation monitoring device and method based on light reflection and refraction. The application adopts a pure optical light path transmission mode. When the blade deforms, the internal light path of the optical transmission channel is offset, the light reflection angle and the refraction angle are changed, and the light signal change amount is converted into the blade deformation value according to the principle. Thus, the influence of environmental factors is fundamentally avoided, and the device can stably operate all day long. Meanwhile, the millimeter-level or even smaller deformation of the blade bending and twisting can be sensitively identified by accurately analyzing the light intensity change. The application does not need precise demodulation equipment and complex welding processes, the light path structure is simple, the cost of the core device is controllable, and there is no problem of fragile optical fiber damage, so that the manufacturing cost and the later maintenance difficulty are greatly reduced. In addition, the application has no aging and falling problems, and can stably operate for a long time. Thus, the application provides an economical, durable and reliable innovative monitoring method for wind power safety operation and maintenance.

Description

Technical Field

[0001] This invention belongs to the field of safety monitoring technology for wind power generation equipment, specifically relating to a device and method for monitoring the deformation of wind turbine blades based on light reflection and refraction. Background Technology

[0002] As the core component for wind energy capture, wind turbine blades operate in harsh high-altitude environments for extended periods. They are continuously subjected to alternating wind loads, diurnal temperature variations, corrosive media, and extreme weather conditions, making them highly susceptible to fatigue deformation and cracking. In severe cases, this can lead to blade breakage and even turbine collapse, resulting in significant safety accidents, causing substantial economic losses and posing substantial safety hazards. Therefore, real-time online monitoring of blade deformation and proactive fault detection are crucial for ensuring the safe and stable operation of wind farms.

[0003] Currently, the mainstream blade deformation monitoring technologies in the industry mainly include the following: (1) Resistance strain gauge monitoring technology: The strain gauge is attached to the surface of the blade and the deformation is reflected by the change of resistance. It has a low cost, but it is susceptible to external electromagnetic interference, has poor weather resistance, and will experience aging, falling off and accuracy decay after long-term use, making it impossible to achieve long-term stable monitoring. (2) Fiber optic grating sensing and monitoring technology: It has high accuracy and strong anti-electromagnetic interference capability, but the fiber material is fragile, the installation process is complex, the cost is high, and the later maintenance is difficult, making it difficult to popularize and apply in small and medium-sized wind turbines and large-scale wind farms. (3) Machine vision monitoring technology: The shape of the blade is captured by an external camera and the image is analyzed to determine the deformation. However, it is easily affected by environmental factors such as rain, snow, fog, haze, sunlight, wind and sand. It cannot work normally in bad weather and it is difficult to identify millimeter-level small deformations. The monitoring is lagging. (4) Accelerometer monitoring technology: Deformation is indirectly calculated through vibration parameters, but the error is large and it cannot accurately measure static deformation, resulting in insufficient practicality.

[0004] Therefore, based on the aforementioned shortcomings, there is an urgent need to provide a purely optical, non-contact, and low-cost monitoring solution to effectively avoid interference from the external environment and achieve high-precision, all-weather, real-time online monitoring of blade bending and torsional composite deformation. Summary of the Invention

[0005] The purpose of this invention is to provide a wind turbine blade deformation monitoring device and method based on light reflection and refraction, in order to solve the problems of existing technologies, such as inability to achieve long-term stable monitoring, high cost, susceptibility to environmental factors, inability to identify millimeter-level micro-deformations, and large errors.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: Firstly, a wind turbine blade deformation monitoring device based on light reflection and refraction is provided, comprising: A light source module is installed on the fixed end of the flexible structure under test and is used to emit a monochromatic parallel beam of light. The fixed end is the end of the flexible structure under test that is fixed to the mounting carrier, and the flexible structure under test includes a wind turbine blade. An optical transmission channel for transmitting the monochromatic parallel beam, wherein the optical transmission channel is arranged along the length direction of the flexible structure under test and is rigidly connected to the flexible structure under test so as to maintain synchronous deformation with the flexible structure under test; An optical receiving module is located at the end of the flexible structure under test that is furthest from the mounting carrier. It is used to collect the monochromatic parallel beam transmitted through the optical transmission channel, obtain the optical signal, and convert the optical signal into an electrical signal for transmission to the data processing module. The data processing module is electrically connected to the optical receiving module and is used to determine the intensity of the received light based on the electrical signal, and to calculate the real-time deformation of the flexible structure under test based on the intensity of the received light.

[0007] Based on the above disclosure, this invention abandons the traditional electrical sensing and visual imaging path, and adopts a pure optical path transmission method. When the blade deforms, the optical path inside the optical transmission channel shifts, and the light reflection and refraction angles change accordingly. This principle is used to convert the change in light signal into a numerical value of blade deformation, thereby achieving accurate measurement of the degree of deformation. In this way, this invention fundamentally avoids the influence of environmental factors such as electromagnetic interference, rain, snow, fog, haze, and changes in light intensity, and can operate stably in all weather conditions. At the same time, by accurately analyzing changes in light intensity, it can sensitively identify millimeter-level or even smaller deformations of blade bending and twisting, improving monitoring accuracy and real-time performance. All of these methods significantly outperform machine vision and indirect acceleration calculation schemes. Furthermore, compared to fiber Bragg grating technology, this invention does not require precision demodulation equipment or complex fusion splicing processes, has a simple optical path structure, controllable core component costs, and avoids the problem of fragile optical fibers being easily damaged, greatly reducing manufacturing costs and the difficulty of subsequent maintenance. In addition, the light source and the light receiving module are respectively located at the fixed end and the far end of the blade, and the optical transmission channel is rigidly connected to the blade, conforming to dynamic deformation, without the risk of aging or detachment of adhesives, and ensuring long-term stable operation. Thus, this invention provides an economical, durable, and reliable innovative monitoring method for wind power safety operation and maintenance, making it very suitable for large-scale application and promotion.

[0008] In one possible design, the optical transmission channel includes: a flexible optical waveguide and a reflection and refraction interface array, wherein the flexible optical waveguide is arranged along the length direction of the flexible structure under test and is rigidly connected to the flexible structure under test. The reflection and refraction interface array includes: several V-shaped grooves; The flexible optical waveguide has grooves arranged at preset intervals on its inner surface along its length. Each groove has a depth of 0.1 mm and an included angle of 90°. The surface of each groove is covered with a reflective film.

[0009] In one possible design, the light source module includes: a collimated laser emitter, a regulated power supply, and a fixed base. The collimated laser emitter is mounted on the fixed end of the flexible structure under test via the fixed base. The regulated power supply is electrically connected to the power supply end of the collimated laser emitter, and the emitting end of the collimated laser emitter faces the input end of the optical transmission channel, for emitting the monochromatic parallel beam to the optical transmission channel.

[0010] In one possible design, the light receiving module includes a CMOS photosensitive array and a photoelectric signal converter; wherein the CMOS photosensitive array is used to receive a monochromatic parallel light beam transmitted by the optical transmission channel to generate an optical signal and transmit the optical signal to the photoelectric signal converter, and the photoelectric signal converter is electrically connected to the data processing module to convert the optical signal into an electrical signal and transmit it to the data processing module.

[0011] In one possible design, the intensity of the received light is the amplitude vector of the electrical signal, wherein, when calculating the real-time deformation of the flexible structure under test based on the intensity of the received light, the data processing module is configured as follows: Obtain the reference light intensity when the flexible structural component under test is in a state of no load and no deformation; The intensity change vector is calculated based on the received light intensity and the reference light intensity. Using the light intensity variation vector, an observation equation based on the unit curvature vector is constructed, wherein the unit curvature vector contains the bending curvature of the flexible structure under test at different reflection point positions along the length direction; Solve the observation equations to obtain the unit curvature vector; The deflection curve of the flexible structure under test is obtained by inversion using the unit curvature vector; Based on the deflection curve, the real-time deformation of the flexible structural component under test is determined.

[0012] In one possible design, the observation equation is: y = H·x + e; In the formula, y represents the light intensity change vector, H is the sensitivity matrix, x represents the unit curvature vector to be inverted, and e represents the measurement noise.

[0013] In one possible design, the observation equation is solved using Tikhonov regularization to obtain the element curvature vector, wherein the equation for solving the element curvature vector is: ; In the formula, x represents the unit curvature vector, H is the sensitivity matrix, and y represents the light intensity change vector. Represents the regularization parameter. The curvature smoothing constraint matrix is... This indicates the transpose operation.

[0014] In one possible design, when the deflection curve of the flexible structure under test is obtained by inversion using the unit curvature vector, the data processing module is configured as follows: The deflection curve is generated based on the unit curvature vector and using the following formula; ; In the formula, This represents the deflection of the flexible structural component under test at arc length position s, where s is the arc length from the fixed end along the length direction to the target point, and t is the outer layer integration variable, representing any intermediate arc length position between the fixed end and the target point. , Let be the inner-layer integral variable, representing any arc length position from the fixed end to the intermediate arc length position t. , This indicates the position of the flexible structural component under test at the arc length position. The curvature at the point, where the target point is the endpoint of the flexible structure to be tested, away from the mounting carrier. It is obtained through the unit curvature vector, and each reflection point position corresponds to an arc length position.

[0015] One possible design also includes: an early warning module; The data processing module is used to send the real-time deformation amount to the early warning module; The early warning module is used to generate an alarm command and send it to the remote monitoring platform when the real-time deformation exceeds a preset safety threshold, and to send the real-time deformation to the remote monitoring platform for storage.

[0016] Secondly, a method for monitoring the deformation of wind turbine blades based on light reflection and refraction is provided, implemented based on the first aspect or any possible design of the wind turbine blade deformation monitoring device based on light reflection and refraction, wherein the method includes: The monochromatic parallel beam transmitted through the optical transmission channel is collected to obtain the optical signal; Convert optical signals into electrical signals; The intensity of the received light is determined based on the electrical signal. The real-time deformation of the flexible structural component under test is calculated based on the received light intensity.

[0017] Thirdly, another wind turbine blade deformation monitoring device based on light reflection and refraction is provided. Taking the device as an electronic device as an example, it includes a memory, a processor, and a transceiver that are connected in sequence. The memory is used to store computer programs, the transceiver is used to send and receive messages, and the processor is used to read the computer programs and execute the wind turbine blade deformation monitoring method based on light reflection and refraction as described in the second aspect.

[0018] Fourthly, a storage medium is provided, on which instructions are stored, which, when executed on a computer, perform the wind turbine blade deformation monitoring method based on light reflection and refraction as described in the second aspect.

[0019] Fifthly, a computer program product containing instructions is provided, which, when executed on a computer, causes the computer to perform the wind turbine blade deformation monitoring method based on light reflection and refraction as described in the second aspect.

[0020] Beneficial effects: (1) This invention abandons the traditional electrical sensing and visual imaging path and adopts a pure optical path transmission method. When the blade deforms, the optical path inside the optical transmission channel shifts, and the light reflection angle and refraction angle change accordingly. This principle is used to convert the change in light signal into the value of blade deformation, thereby achieving accurate measurement of the degree of deformation. In this way, this invention fundamentally avoids the influence of environmental factors such as electromagnetic interference, rain, snow, fog, haze, and light changes, and can operate stably in all weather conditions. At the same time, by accurately analyzing the changes in light intensity, it can sensitively identify millimeter-level or even smaller deformations of blade bending and twisting, and the monitoring accuracy and real-time performance are significantly improved. This invention surpasses machine vision and indirect acceleration estimation methods. Furthermore, compared to fiber Bragg grating technology, it eliminates the need for sophisticated demodulation equipment and complex fusion splicing processes, resulting in a simple optical path structure, controllable core component costs, and the elimination of the vulnerability of fragile optical fibers, significantly reducing manufacturing costs and post-maintenance complexity. Additionally, the light source and light receiving module are located at the fixed and remote ends of the blade, respectively, with the optical transmission channel rigidly connected to the blade, ensuring consistent deformation and eliminating concerns about aging, detachment, or long-term stability. Thus, this invention provides an economical, durable, and reliable innovative monitoring method for wind power safety operation and maintenance, making it highly suitable for large-scale application and promotion.

[0021] (2) High versatility: It is suitable for onshore and offshore wind turbine blades of different power and length, without the need for specific modifications, and has extremely high adaptability.

[0022] (3) Comprehensive monitoring and strong practicality: It can monitor two composite deformation modes of blade bending and torsion at the same time, and the data is transmitted in real time and automatically stored, realizing unattended fully automatic monitoring and greatly reducing operation and maintenance costs. Attached Figure Description

[0023] Figure 1 A structural diagram of a wind turbine blade deformation monitoring device based on light reflection and refraction provided in an embodiment of the present invention; Figure 2 A flowchart illustrating the steps of wind turbine blade deformation monitoring based on light reflection and refraction, provided for embodiments of the present invention; Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in conjunction with the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following description of the structure of the accompanying drawings is only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0025] It should be understood that although the terms first, second, etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit, without departing from the scope of the exemplary embodiments of the invention.

[0026] It should be understood that the term "and / or" that may appear in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" that may appear in this document describes another relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " that may appear in this document generally indicates that the related objects before and after it are in an "or" relationship.

[0027] Example: See Figure 1As shown, the wind turbine blade deformation monitoring device based on light reflection and refraction provided in the first aspect of this embodiment may include, but is not limited to, five parts: a light source module, an optical transmission channel, a light receiving module, a data processing module, and an early warning module. For example, the device adopts an integrated layout, with all optical sensing components embedded inside the wind turbine blade, without damaging the original structure of the blade or affecting its aerodynamic performance. Furthermore, the data processing module and the early warning module are installed in the wind turbine nacelle control cabinet, which facilitates wiring and operation and maintenance management.

[0028] The installation structure and corresponding working process of each of the aforementioned modules are as follows: A light source module is installed at the fixed end of the flexible structure under test and is used to emit a monochromatic parallel light beam. The fixed end is the end where the flexible structure under test is fixed to the mounting carrier, and the flexible structure under test includes a wind turbine blade. In a specific implementation, the light source module is installed on the inner side of the root of the wind turbine blade, close to the hub end of the mounting carrier. Of course, it also adopts an internal layout and is set inside the blade.

[0029] Meanwhile, the light source module may include, but is not limited to, a collimated laser emitter, a regulated power supply (DC regulated power supply), and a metal mounting base; wherein, the collimated laser emitter is mounted on the fixed end of the flexible structure under test via the mounting base, the regulated power supply is electrically connected to the power supply end of the collimated laser emitter, and the emitting end of the collimated laser emitter faces the input end of the optical transmission channel, for emitting a monochromatic parallel beam to the optical transmission channel.

[0030] Furthermore, for example, a collimated laser emitter can be, but is not limited to, an 850nm VCSEL laser, equipped with a collimating lens, with an adjustable output power range of 1-50mW, and the light source module has a built-in pulse modulation circuit that can generate pulsed light with a pulse width of 10ns; in this way, the light source module can provide a stable incident light source, ensuring that the beam is accurately injected along the optical transmission channel axis, providing a foundation for optical path transmission.

[0031] After describing the structure of the light source module, the arrangement of the optical transmission channel is disclosed below: In this embodiment, the optical transmission channel is used to transmit the monochromatic parallel light beam emitted by the light source module. The optical transmission channel is arranged along the length direction of the flexible structure under test and is rigidly connected to the flexible structure under test. In this way, as a dedicated channel for light transmission, it is completely rigidly attached to the blade, which can ensure that when the blade deforms (such as bending or twisting), the channel will simultaneously undergo bending and twisting deformation (that is, the channel and the flexible structure under test deform synchronously), thereby changing the internal optical path and realizing a direct correlation between deformation and optical path change.

[0032] In one specific embodiment, the optical transmission channel may include, but is not limited to, a flexible optical waveguide and a reflection and refraction interface array, wherein the flexible optical waveguide is arranged along the length direction of the flexible structure under test (e.g., along the blade spanwise, fitting the blade main beam or internal reinforcing ribs throughout its length) and is rigidly connected to the flexible structure under test; specifically, for example, the flexible optical waveguide has a width of 5 mm and a thickness of 0.5 mm, is integrally formed with the composite material during blade layup, and the main material of the waveguide is polymethyl methacrylate (PMMA) with a refractive index n1=1.49.

[0033] Furthermore, the aforementioned reflection and refraction interface array includes: a plurality of V-shaped grooves; wherein, the grooves are arranged at preset distances along the length direction on the inner surface of the flexible optical waveguide (e.g., a group of V-shaped grooves are arranged every 10cm), each groove has a depth of 0.1mm, an included angle of 90°, and the surface of each groove is covered with a reflective film (e.g., an aluminum-plated reflective film); this structure, when the blade is not deformed, vertically reflects part of the light to the receiving end direction.

[0034] Furthermore, this embodiment also provides another optical transmission channel, which includes a sealed cavity (the cavity is made of a highly transparent, highly tough, fatigue-resistant flexible engineering plastic, such as acrylic, polycarbonate, etc.). The sealed cavity is arranged along the length of the flexible structure under test and is rigidly connected to the flexible structure under test. Specifically, the inner wall of the sealed cavity is covered with a reflective coating, and the cavity is a vacuum environment or filled with a transmission medium with a fixed refractive index. For example, the high reflective coating is a silver-plated coating or an aluminum high reflective coating, and the transmission medium is a transparent silicone or optical resin medium.

[0035] Thus, by using any of the aforementioned optical transmission channels as a dedicated channel for light transmission, the channel can bend and twist synchronously when the blade deforms, thereby altering the internal optical path. Specifically, when the wind turbine is running and the blades are bent and twisted under wind load, the optical transmission channel bends and twists synchronously, causing the internal optical path to shift. Consequently, the light reflection and refraction angles change, resulting in a decrease in the light intensity reaching the light receiving module. Therefore, by comparing the real-time signal with the reference signal, the change in the optical signal can be converted into a blade deformation value, thereby achieving accurate measurement of the degree of deformation.

[0036] Optionally, the monochromatic parallel beam transmitted by the optical transmission channel is received by the optical receiving module, and its operation is as follows: An optical receiving module is located at the end of the flexible structure under test that is furthest from the mounting carrier. It is used to collect the monochromatic parallel beam transmitted through the optical transmission channel, obtain the optical signal, and convert the optical signal into an electrical signal for transmission to the data processing module.

[0037] In practical applications, the optical receiving module is installed on the inner side of the tip of the wind turbine blade, facing the output end of the optical transmission channel. For example, the optical receiving module may include, but is not limited to, a CMOS photosensitive array and a photoelectric signal converter. In specific implementation, the CMOS photosensitive array is used to receive the monochromatic parallel light beam transmitted by the optical transmission channel to generate an optical signal, and transmits the optical signal to the photoelectric signal converter. The photoelectric signal converter is electrically connected to the data processing module and is used to convert the optical signal into an electrical signal and transmit it to the data processing module.

[0038] Thus, the optical receiving module fully receives the light transmitted through the channel and converts the optical signal into an electrical signal, which is then transmitted to the data processing module. The data processing module then calculates the real-time deformation of the flexible structural component under test based on the electrical signal. The process is as follows: The data processing module, electrically connected to the optical receiving module, is used to determine the intensity of the received light based on the electrical signal, and to calculate the real-time deformation of the flexible structure under test based on the intensity of the received light. In this embodiment, the receiving end of the optical receiving module detects the optical power or the amplitude of the optical signal. After signal conversion, the intensity of the received light is essentially the amplitude vector of the electrical signal converted from the optical signal, i.e., the voltage amplitude (the digital quantity of the light intensity response obtained after photoelectric conversion and analog-to-digital sampling). Therefore, this embodiment uses this amplitude vector as input to calculate the deformation.

[0039] In practical implementation, this embodiment calculates the real-time deformation of the flexible structure under test by comparing the real-time light intensity with the reference light intensity. That is, when the real-time deformation of the flexible structure under test is calculated based on the received light intensity, the data processing module is configured to perform the following operations: Step 1: Obtain the reference light intensity when the flexible structure under test is in a state of no load and no deformation; In this embodiment, when the blade is not under load and has not deformed, the pulse light emitted by the light source module propagates along the optical waveguide. After being reflected by each groove, part of the light continues to propagate along the waveguide axis to the receiving end. At this time, the optical receiving module receives the optical signal and converts it into an electrical signal for transmission to the data processing module. The data processing module records the amplitude distribution of the received electrical signal sequence and establishes a reference feature vector (i.e., reference light intensity) A0 = [a1, a2,…, an], where ai (i=1,2,...,n, n is the total number of emission points) corresponds to the amplitude (i.e., contribution component) of the i-th reflection point position.

[0040] Thus, after obtaining the reference light intensity, a light intensity comparison can be performed, as shown in step 2 below.

[0041] Step 2: Calculate the light intensity change vector based on the received light intensity and the reference light intensity. In this embodiment, the light intensity change vector is obtained by subtracting the two. Then, an observation equation based on the unit curvature vector can be established based on this, as shown in Step 3 below.

[0042] Step 3: Using the light intensity change vector, construct an observation equation based on the unit curvature vector, wherein the unit curvature vector contains the bending curvature of the flexible structure under test at different reflection point positions along the length direction.

[0043] In this embodiment, when the blade undergoes bending deformation, the optical waveguide experiences a local curvature change due to the blade bending. Let the bending curvature be κ(s), then the relationship between the normal deflection angle θi of the reflecting surface at the i-th reflection point and the curvature is: θi=∫κ(s) ds (integration along the light path); In the formula, s represents the arc length position on the flexible structural component to be tested, which corresponds one-to-one with the position of the reflection point.

[0044] Based on this, the deflection of the reflecting surface causes the reflected light to deviate from its original axial propagation direction, and the light intensity attenuation rate ηi contributed by the i-th reflection point satisfies: ; In the formula, α is a coefficient related to the reflective surface structure, which is determined through calibration experiments.

[0045] Finally, the total light intensity I detected by the receiver of the light receiving module is the sum of the contributions of each reflection point. Therefore, the data processing module monitors the change of I in real time and combines it with the pre-established light intensity-curvature mapping model to inversely derive the bending curvature κ(s) of each segment of the blade, and then further integrates to obtain the deflection deformation curve of the blade.

[0046] Therefore, based on the above, the blade can be divided into N units (i.e., arc segments) along its length, with each unit corresponding to a reflection point position. Then, a regularization-based deformation reconstruction algorithm is used to establish the observation equation, the expression of which is: y = H·x + e; In the formula, y represents the light intensity change vector, H is the sensitivity matrix (obtained through finite element simulation or calibration experiment), x represents the unit curvature vector to be inverted, and e represents the measurement noise.

[0047] Thus, after constructing the observation equation, the equation can be solved to obtain the unit curvature vector, as shown in step 3 below.

[0048] Step 3: Solve the observation equation to obtain the unit curvature vector. In specific applications, examples, but not limited to, using Tikhonov regularization (also known as ridge regression, a linear regression analysis method), can be used to solve the observation equation to obtain the unit curvature vector. The equation for solving the unit curvature vector is: ; In the formula, x represents the unit curvature vector, H is the sensitivity matrix, and y represents the light intensity change vector. Represents the regularization parameter. This is the curvature smoothing constraint matrix (a preset matrix used to constrain the curvature range). This indicates the transpose operation.

[0049] The following explains the origin of the equation for solving: The observation equation represents the sum of the actual measured light intensity change vector (H·x) predicted by the physical model and the measurement noise. That is, due to the existence of e, the ideal equation y = H·x can never be exactly true. Therefore, we can only find an optimal approximate solution, namely: Constructing the objective function, transforming e into a minimization objective, that is, minimizing the error between H·x and e, can be expressed as: .

[0050] To solve the aforementioned least squares problem, Tikhonov introduced a method concerning... and The regularization term is used to constrain the smoothness of the solution. After adding the regularization term, the analytical solution that takes the extreme value of the objective function can be used to obtain the aforementioned solution equation (i.e., take the derivative and then set the derivative to 0 to establish the aforementioned solution equation). Of course, the Tikhonov regularization method is a commonly used solution method, and its principle will not be elaborated here.

[0051] After obtaining the unit curvature vector based on the aforementioned formula, curvature integration can be performed to obtain the deflection curve, as shown in step 4 below.

[0052] Step 4: Using the unit curvature vector, the deflection curve of the flexible structure under test is obtained by inversion; in specific implementation, for example, but not limited to, the following formula can be used to generate the deflection curve.

[0053] ; In the formula, This represents the deflection of the flexible structural component under test at arc length position s, where s is the arc length from the fixed end along the length direction to the target point, and t is the outer layer integration variable, representing any intermediate arc length position between the fixed end and the target point. , Let be the inner-layer integration variable, representing any arc length position from the fixed end to the intermediate arc length position t. (0 represents the leaf root, i.e., the fixed end). This indicates the position of the flexible structural component under test at the arc length position. The curvature at the point, where the target point is the endpoint of the flexible structure to be tested, away from the mounting carrier. It is obtained through the unit curvature vector, and each reflection point position corresponds to an arc length position.

[0054] Thus, based on the aforementioned formula, after calculating the deflection of the flexible structural component under test at different arc length positions, the real-time deformation of the flexible structural component under test can be determined based on this, as shown in step 5 below.

[0055] Step 5: Based on the deflection curve, determine the real-time deformation of the flexible structural component under test; in this embodiment, the horizontal axis of the deflection curve represents the arc length position when it is not deformed, while the vertical axis is the deflection at each arc length position, which is the bending deformation of the corresponding section.

[0056] Thus, based on the aforementioned steps 1 to 5, after calculating the real-time deformation of the flexible structural component under test at different arc length positions, deformation early warning can be provided, i.e.: The data processing module is used to send the real-time deformation amount to the early warning module; and the early warning module is used to generate an alarm command and send it to the remote monitoring platform when the real-time deformation amount is greater than a preset safety threshold, and to send the real-time deformation amount to the remote monitoring platform for storage.

[0057] In this embodiment, when the real-time deformation at any arc length position exceeds a preset safety threshold, an alarm command is generated. Simultaneously, a local audible and visual warning can be triggered, as well as the warning mechanism of the remote monitoring platform. The real-time deformation data, alarm time, and fault location (i.e., arc length position and corresponding wind turbine blade number) are wirelessly transmitted to the wind farm remote monitoring platform, realizing remote warning and data retention. In specific applications, the remote monitoring platform can automatically generate monitoring reports, which are convenient for operation and maintenance personnel to view, analyze, and handle.

[0058] Furthermore, this embodiment also includes a tiered early warning mechanism, which sets first-level and second-level early warning thresholds (both of which are greater than the preset safety threshold). When the deformation amount does not exceed the preset safety threshold, monitoring continues; when it exceeds the first-level threshold, a mild early warning is issued; when it exceeds the second-level threshold, a severe alarm is issued. In the event of a severe alarm, the fan is shut down to achieve shutdown protection.

[0059] In addition, the aforementioned data processing module can, but is not limited to, use an embedded microcontroller (such as the STM32 series); the early warning module includes an audible and visual alarm, a wireless transmission unit (4G, 5G, LoRa communication unit, etc.) and a processor to realize local audible and visual alarms and to perform data transmission.

[0060] In this embodiment, the method is not only applicable to wind turbine blades and wind turbine impellers, but can also be adapted to real-time deformation monitoring of large flexible mechanical components, such as bridges, mines, derricks, and signal towers.

[0061] Therefore, through the detailed description of the wind turbine blade deformation monitoring device based on light reflection and refraction, the present invention has the following beneficial effects: (1) High monitoring accuracy and high sensitivity: It can accurately identify millimeter-level micro deformations, capture early fatigue deformation of blades, realize early warning of faults, and avoid major accidents.

[0062] (2) Extremely strong anti-interference ability: The fully enclosed optical structure is completely unaffected by external electromagnetic interference, rain, snow, fog, haze, light intensity and other environmental factors, and can work stably in all weather and all working conditions.

[0063] (3) Low cost and easy to popularize: The core components are all conventional industrial products, and the cost is much lower than that of fiber optic sensing systems. The installation process is simple and does not require complex wiring, making it suitable for large-scale wind farm applications.

[0064] (4) Good durability and longer service life: No exposed electronic components, no mechanical friction loss, does not damage the structural strength of the blade, resistant to aging and corrosion, and its service life can be synchronized with the wind turbine blade.

[0065] (5) Comprehensive monitoring and strong practicality: It can monitor two composite deformation modes of blade bending and torsion at the same time, and the data is transmitted in real time and automatically stored, realizing unattended fully automatic monitoring and greatly reducing operation and maintenance costs. (6) High versatility: It is suitable for onshore and offshore wind turbine blades of different power and length, without the need for specific modifications, and has extremely high adaptability.

[0066] like Figure 2 As shown, the second aspect of this embodiment provides a method for monitoring the deformation of wind turbine blades based on light reflection and refraction. This method is implemented based on the wind turbine blade deformation monitoring device based on light reflection and refraction described in the first aspect of the embodiment. The operation process of the method is as follows: steps S1 to S4 are shown below. S1. Acquire the monochromatic parallel beam transmitted through the optical transmission channel to obtain the optical signal.

[0067] S2. Convert the optical signal into an electrical signal.

[0068] S3. Determine the intensity of the received light based on the electrical signal.

[0069] S4. Calculate the real-time deformation of the flexible structural component under test based on the received light intensity.

[0070] The working process, working details and technical effects of the method provided in this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0071] like Figure 3 As shown, the third aspect of this embodiment provides another wind turbine blade deformation monitoring device based on light reflection and refraction. Taking the device as an electronic device as an example, it includes: a memory, a processor, and a transceiver connected in sequence. The memory is used to store computer programs, the transceiver is used to send and receive messages, and the processor is used to read the computer programs and execute the wind turbine blade deformation monitoring method based on light reflection and refraction as described in the second aspect of the embodiment.

[0072] For specific examples, the memory may include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out (FIFO) memory, and / or first-in-last-out (FILO) memory, etc.; specifically, the processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor may be implemented using at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), PLA (Programmable Logic Array). The processor may also include a main processor and a coprocessor. The main processor, also known as the CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state.

[0073] In some embodiments, the processor may integrate a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the screen. For example, the processor may not be limited to microprocessors of the STM32F105 series, reduced instruction set computer (RISC) microprocessors, x86 architecture processors, or processors with integrated neural network processing units (NPUs). The transceiver may be, but is not limited to, a Wi-Fi transceiver, a Bluetooth transceiver, a General Packet Radio Service (GPRS) transceiver, a ZigBee transceiver (a low-power LAN protocol based on the IEEE 802.15.4 standard), a 3G transceiver, a 4G transceiver, and / or a 5G transceiver. Furthermore, the device may also include, but is not limited to, a power module, a display screen, and other necessary components.

[0074] The working process, working details and technical effects of the electronic device provided in this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0075] The fourth aspect of this embodiment provides a storage medium that stores instructions containing the wind turbine blade deformation monitoring method based on light reflection and refraction as described in the second aspect of the embodiment. That is, the storage medium stores instructions that, when executed on a computer, perform the wind turbine blade deformation monitoring method based on light reflection and refraction as described in the second aspect of the embodiment.

[0076] The storage medium refers to a carrier for storing data, which may include, but is not limited to, floppy disks, optical disks, hard disks, flash memory, USB flash drives, and / or memory sticks. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0077] The working process, working details and technical effects of the storage medium provided in this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0078] The fifth aspect of this embodiment provides a computer program product containing instructions that, when executed on a computer, cause the computer to perform the wind turbine blade deformation monitoring method based on light reflection and refraction as described in the second aspect of this embodiment. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.

[0079] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wind turbine blade deformation monitoring device based on light reflection and refraction, characterized in that, include: A light source module is installed on the fixed end of the flexible structure under test and is used to emit a monochromatic parallel light beam. The fixed end is the end of the flexible structure under test that is fixed to the mounting carrier, and the flexible structure under test includes a wind turbine blade. An optical transmission channel for transmitting the monochromatic parallel beam, wherein the optical transmission channel is arranged along the length direction of the flexible structure under test and is rigidly connected to the flexible structure under test so as to maintain synchronous deformation with the flexible structure under test; An optical receiving module is located at the end of the flexible structure under test that is furthest from the mounting carrier. It is used to collect the monochromatic parallel beam transmitted through the optical transmission channel, obtain the optical signal, and convert the optical signal into an electrical signal for transmission to the data processing module. The data processing module is electrically connected to the optical receiving module and is used to determine the intensity of the received light based on the electrical signal, and to calculate the real-time deformation of the flexible structure under test based on the intensity of the received light.

2. The wind turbine blade deformation monitoring device based on light reflection and refraction according to claim 1, characterized in that, The optical transmission channel includes: a flexible optical waveguide and a reflection and refraction interface array, wherein the flexible optical waveguide is arranged along the length direction of the flexible structure under test and is rigidly connected to the flexible structure under test. The reflection and refraction interface array includes: several V-shaped grooves; The flexible optical waveguide has grooves arranged at preset intervals on its inner surface along its length. Each groove has a depth of 0.1 mm and an included angle of 90°. The surface of each groove is covered with a reflective film.

3. The wind turbine blade deformation monitoring device based on light reflection and refraction according to claim 1, characterized in that, The light source module includes a collimated laser emitter, a regulated power supply, and a fixed base. The collimated laser emitter is mounted on the fixed end of the flexible structure under test via the fixed base. The regulated power supply is electrically connected to the power supply end of the collimated laser emitter, and the emitting end of the collimated laser emitter faces the input end of the optical transmission channel, for emitting the monochromatic parallel beam to the optical transmission channel.

4. The wind turbine blade deformation monitoring device based on light reflection and refraction according to claim 1, characterized in that, The optical receiving module includes a CMOS photosensitive array and a photoelectric signal converter; wherein, the CMOS photosensitive array is used to receive the monochromatic parallel light beam transmitted by the optical transmission channel to generate an optical signal and transmit the optical signal to the photoelectric signal converter, and the photoelectric signal converter is electrically connected to the data processing module to convert the optical signal into an electrical signal and transmit it to the data processing module.

5. The wind turbine blade deformation monitoring device based on light reflection and refraction according to claim 1, characterized in that, The received light intensity is the amplitude vector of the electrical signal. When calculating the real-time deformation of the flexible structural component under test based on the received light intensity, the data processing module is configured as follows: Obtain the reference light intensity when the flexible structural component under test is in a state of no load and no deformation; The intensity change vector is calculated based on the received light intensity and the reference light intensity. Using the light intensity variation vector, an observation equation based on the unit curvature vector is constructed, wherein the unit curvature vector contains the bending curvature of the flexible structure under test at different reflection point positions along the length direction; Solve the observation equations to obtain the unit curvature vector; The deflection curve of the flexible structure under test is obtained by inversion using the unit curvature vector; Based on the deflection curve, the real-time deformation of the flexible structural component under test is determined.

6. The wind turbine blade deformation monitoring device based on light reflection and refraction according to claim 5, characterized in that, The observation equation is: y = H·x + e; In the formula, y represents the light intensity change vector, H is the sensitivity matrix, x represents the unit curvature vector to be inverted, and e represents the measurement noise.

7. The wind turbine blade deformation monitoring device based on light reflection and refraction according to claim 5, characterized in that, The observation equation is solved using Tikhonov regularization to obtain the element curvature vector, wherein the equation for solving the element curvature vector is: ； In the formula, x represents the unit curvature vector, H is the sensitivity matrix, and y represents the light intensity change vector. Represents the regularization parameter. The curvature smoothing constraint matrix is... This indicates the transpose operation.

8. The wind turbine blade deformation monitoring device based on light reflection and refraction according to claim 5, characterized in that, When the deflection curve of the flexible structure under test is obtained by inversion using the unit curvature vector, the data processing module is configured as follows: The deflection curve is generated based on the unit curvature vector and using the following formula; ； In the formula, This represents the deflection of the flexible structural component under test at arc length position s, where s is the arc length from the fixed end along the length direction to the target point, and t is the outer layer integration variable, representing any intermediate arc length position between the fixed end and the target point. , Let be the inner-layer integration variable, representing any arc length position from the fixed end to the intermediate arc length position t. , This indicates the position of the flexible structural component under test at the arc length. The curvature at the point, where the target point is the endpoint of the flexible structure to be tested, away from the mounting carrier. It is obtained through the unit curvature vector, and each reflection point position corresponds to an arc length position.

9. The wind turbine blade deformation monitoring device based on light reflection and refraction according to claim 1, characterized in that, Also includes: Early warning module; The data processing module is used to send the real-time deformation amount to the early warning module; The early warning module is used to generate an alarm command and send it to the remote monitoring platform when the real-time deformation exceeds a preset safety threshold, and to send the real-time deformation to the remote monitoring platform for storage.

10. A method for monitoring the deformation of wind turbine blades based on light reflection and refraction, characterized in that, The method is implemented based on the wind turbine blade deformation monitoring device based on light reflection and refraction as described in any one of claims 1 to 9, wherein the method includes: The monochromatic parallel beam transmitted through the optical transmission channel is collected to obtain the optical signal; Convert optical signals into electrical signals; The intensity of the received light is determined based on the electrical signal. The real-time deformation of the flexible structural component under test is calculated based on the received light intensity.

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