Structural health monitoring systems, energy harvesters, and methods of use thereof

Abstract

A structural monitoring system for a wind turbine blade includes a sensing system disposed in a structural cavity of the wind turbine blade. The sensor system has at least one sensor for detecting and recording anomalies in the wind turbine blade. A vortex generation-based energy harvester for a wind turbine blade is also disclosed. The energy harvester includes a generator configured to generate power and an air turbine having at least one blade operatively connected to the generator. The energy harvester is on the surface of the wind turbine blade to generate a vortex as air flows over an outer surface of the wind turbine blade.

Description

STRUCTURAL HEALTH MONITORING SYSTEMS, ENERGY HARVESTERS, ANDMETHODS OF USE THEREOFCROSS REFERENCE TO RELATED APPLICATIONSThis application claims priority to U.S. Provisional Application No. 63 / 654,893, filed on May 31, 2024 and U.S. Provisional Application No. 63 / 654,894, filed on May 31, 2024, the contents of both of which are hereby incorporated by reference in their entirety.FEDERAL RESEARCH STATEMENTThis invention was made with government support under award number 1916715 awarded by the National Science Foundation and under award number DE-EE0008968 awarded by the Department of Energy. The government has certain rights in the invention.BACKGROUND

[0001] Monitoring structural damage in wind turbine blades is essential for ensuring safe and reliable operation. However, this task remains challenging due to the blades’ substantial size, complex geometry, and continuous rotational movement. Existing inspection methods (automated or manual) often rely on external evaluations, are costly to deploy, lack continuous monitoring capability, or are insufficient for detecting internal blade damage.

[0002] Currently, wind turbine blades (and similar structures) lack internal sensors capable of operating during normal turbine function. A primary barrier to integrating such sensors is the difficulty of delivering power from the stationary hub to each rotating blade. With blade lengths often exceeding 100 meters, running cables to power sensors is both technically challenging and economically unfeasible. To enable long-term, cable-free sensor operation without reliance on batteries, localized energy harvesting is required. Although alternative energy harvesting methods such as piezoelectric, solar, and vibration-based electromagnetic systems have been explored, each exhibits limitations that hinder effective deployment in this context.

[0003] Accordingly, there remains a need for improved systems and methods for inspecting and monitoring wind turbine blades that are cost-effective, offer enhanced monitoring capabilities, and increase accuracy in damage detection. Additionally, there is a need for a power delivery solution capable of sustaining internal sensors for extended periods without external cabling or frequent maintenance.SUMMARY

[0004] An aspect of the present disclosure is a structural monitoring system for a wind turbine blade, the wind turbine blade comprising an internal blade surface forming a structural cavity therein, and an external blade surface, the structural monitoring system comprising: a sensing system disposed in the structural cavity, the sensing system having at least one sensor for detecting and recording anomalies in the wind turbine blade, the sensing system having a transmitter configured to transmit recorded anomalies to a receiver.

[0005] Another aspect is a vortex generation-based energy harvester for a wind turbine blade, the energy harvester comprising: a generator configured to generate power; an air turbine comprising at least one blade operatively connected to the generator; wherein the energy harvester on an outer surface of the wind turbine blade to generate a vortex as air flows over an outer surface of the wind turbine blade.

[0006] Another aspect is a wind turbine blade, comprising: an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin; and an energy harvester positioned an outer surface and con-figured and arranged to generate a vortex as air flows over the outer surface of the wind turbine blade.

[0007] Another aspect is a method of providing power to a structural monitoring system for a wind turbine blade, the wind turbine blade having an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin, the method comprising: providing an energy harvester; and positioning the energy harvester on an outer surface; and generating power with the energy harvester as air flows over the outer surface of the wind turbine blade.

[0008] Another aspect is a method of providing power to a structural monitoring system for a wind turbine blade, the wind turbine blade having an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin, the method comprising: providing an energy harvester comprising a generator configured to generate power; an air turbine comprising at least one blade operatively connected to the generator; positioning the energy harvester on an outer surface; generating power with the energy harvester as air flows over the outer surface of the wind turbine blade; electrically connecting the energy harvester to provide power to the structural monitoring system within the wind turbine blade, the structural monitoring system comprising a sensing system disposed in a structural cavity of the wind turbine blade, the sensing system having at least one sensor for detecting and recording anomalies in the wind turbine blade, the sensing system having a transmitter configured to transmit recorded anomalies to a receiver.

[0009] The above described and other features are exemplified by the following figures and detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The following figures are exemplary embodiments.

[0011] FIG. 1 shows an illustration of an inspection process of a cavity structure, such as a wind turbine blade, with the swarm miniature robotic sensing system, accompanied by a drone that can help inspect or transfer data and power to or from the sensors nodes.

[0012] FIG. 2 shows an illustration of a cavity structure, such as a section of a wind turbine blade, with the miniature sensing robot continuously interrogating for any acoustic sources and other sensing measurands, trying to identify damage or other sources of acoustic aberration (not to scale).

[0013] FIG. 3 shows a sensor package following a track (rack and pinion type) where the mass of the package is distributed on each side of the sensor carriage.

[0014] FIG. 4 shows another embodiment of a sensor package following a track (rack and pinion type) with reduced mass.

[0015] FIG. 5 A shows a CAD model of an updated sensor carriage where the center of gravity is lowered to minimize bending moments, the overall mass is reduced to alleviate centrifugal forces acting on the sensors and the mass is distributed mainly along the track.

[0016] FIG. 5B shows an exemplary embodiment of an updated sensor carriage where the center of gravity is lowered to minimize bending moments, the overall mass is reduced to alleviate centrifugal forces acting on the sensors and the mass is distributed mainly along the track.

[0017] FIG. 6 is an illustration of a wind turbine including a structural health monitoring system according to an aspect of the present disclosure.

[0018] FIG. 7 shows an illustration of an embodiment of an energy harvester described herein.

[0019] FIG. 8 is an illustration of an embodiment of an energy harvester, showing a top- down, cross-sectional view, with an expanded view of the air turbine blades.

[0020] FIG. 9 is an illustration of a side view of an energy harvester on an outer surface of a wind turbine blade according to an aspect of the disclosure.

[0021] FIG. 10 is an illustration of energy harvesters and vortex generators on an outer surface of a wind turbine blade according to an aspect of the disclosure.DETAILED DESCRIPTION

[0022] The present inventors have discovered improved methods and systems for monitoring wind turbine structural health. In particular, a sensing system that can leverage, for example, acoustic microphones, accelerometers, thermal IR sensors, strain sensors, temperature sensors, humidity sensors, conductivity sensors, and video cameras to monitor wind turbine blade structural health is disclosed. Because of the challenges with lightning, accessibility, and providing power to a structural health monitoring system within a wind turbine blade, the low power structural health monitoring system should be rechargeable, battery operated (> 1 year life), self-powered through energy harvesting, or wired with lightning protection. The sensing system can be deployed inside a wind turbine blade. In some aspects, the system can autonomously move to improve its distributed sensing and recharging capability and replaces multi-sensor arrays for doing the distributed sensing for damage detection, identification as well as inspection of enclosed or cavity structures such wind turbine blades. The system may be equipped with lights that will help record images of the enclosure’s internal sections that can be stitched or combined together to create large-scale pictures for visual or autonomous inspection purposes. The sensing system can be used to detect physical aberrations generated by any damage, defect, or due to problems with system operation. For example, sensors can be used to detect icing, cracking, delamination, disbonds, holes, lightning strike damage, water intrusion, cavity internal and external impacts to the structure, as well as erosion.

[0023] To date, there are no other distributed sensing and monitoring systems that can continuously interrogate the blade’s internal and external acoustic response to detect damage. The system described herein will be able to continuously interrogate the condition of the enclosure autonomously and inexpensively.

[0024] The present inventors have further discovered a vortex generation-based energy harvester to provide the required power directly to these sensors, enabling a wireless sensing architecture, reducing the cost and increasing the reliability of the monitoring solution in the challenging field conditions. The vortex generation-based energy harvester is a device that can create power for sensors (e.g., strain, accelerometers, acoustic, camera) and associated electronics (for data processing and transmission) inside of a wind turbine blade without the need to access the turbine or blades. Doing so reduces the need for wiring down the length of the turbine blade which in turn reduces cost and eliminates risks of the wiring being damaged by environmental events or becoming loose from vibration and colliding with other systems. The harvester includes one or multiple miniature air turbines (energy harvesters) mounted on the blade to passively harvest energy from the air as it moves over the blade while parked or duringrotation. For example, an acoustic sensor in a blade monitoring system requires an average of approximately 0.15 watts of power. An energy harvester according to an aspect of the present disclosure resulted in power generation of up to approximately 2 W. Operating conditions when mounted on a wind turbine will likely have higher speeds that would generate an even higher amount of power.

[0025] In an aspect, the sensing system can be inside a wind turbine blade, where the sensors are chemically bonded onto the shear web of a blade and the power needed to energize these sensors can be harvested using the energy harvesters described herein, optionally coupled with a vortex generator, mounted on the outer surface of the blade. The power from the generator can be transmitted using a small wire through the blade or wirelessly through the surface of the blade using an inductive coil or charger.

[0026] Thus, a significant improvement in sensing systems and energy harvesters, particularly as they relate to wind turbine blades is provided by the present disclosure.

[0027] Accordingly, an aspect of the present disclosure is a structural monitoring system for a wind turbine blade. A wind turbine blade comprises an external blade surface and an internal blade surface defining a structural cavity therein. The structural health monitoring system is disposed in the structural cavity of the wind turbine blade. The structural monitoring system comprises a sensing system disposed in the structural cavity. The sensing system has at least one sensor for detecting and recording anomalies in the wind turbine blade. The sensing system further comprises a transmitter capable of transmitting recorded anomalies to a receiver. The receiver can be for example a centralized computer, which may be remotely located from the wind turbine. The centralized computer may be a computing system or processor that is configured to receive signals or data from the structural monitoring system, process the received information, and optionally perform one or more of controlling, monitoring, or decision-making functions based on the input. In some aspects, the structural health monitoring system can be configured to enable remote start and software updates.

[0028] The sensing system comprises at least one sensor which can be, for example, an acoustic microphone, an accelerometer, a thermal IR sensor, a microwave or radar sensor, a strain sensor, a temperature sensor, a humidity sensor, a conductivity sensor, a vibration sensor, or a video camera. In an aspect, the sensing system comprises at least one acoustic microphone. The acoustic microphone is capable of recording an acoustic profile of the interior of the wind turbine blade, allowing for the detecting of acoustic anomalies which may signal damage to the blade. The acoustic microphone can enable detection of damage as well as direction and location.

[0029] In some aspects, the sensing system can include an onboard camera system (e.g., video, thermal, or both) configured to take pictures or record and transmit video of the interrogated areas to help inspect the system during operation or when the rotor is parked. Video may be compressed to save space. Thermal scans of the blade during operation are able to identify cracks and embedded defects due to thermal emissions of the area of interest. Video and images may be further stitched or combined together to create large-scale pictures for visual or autonomous inspection purposes (e.g., using artificial intelligence).

[0030] In some aspects, employing more than one sensor may be advantageous. For example, a combination of sensors including an acoustic microphone, a temperature sensor, an accelerometer, and a vibration sensor in a single sensing system is disclosed. Suitable accelerometers may include piezoelectric, MEMS capacitive, piezoresistive, or strain-gaugebased types, depending on factors such as required sensitivity or frequency range. Suitable vibration sensors for wind turbine applications may include piezoelectric sensors, MEMS accelerometers, strain gauges, and velocity transducers. In some aspects, each sensing system can include a 3-axis accelerometer (e.g., an accelerometer configured to measure acceleration forces along three orthogonal axes (X, Y, and Z), enabling detection of motion or vibration in three-dimensional space), an inertial measurement unit, a temperature sensor, and an acoustic sensor. Accordingly, the sensor may be useful in detecting multiple damage types.

[0031] In some aspects, the sensing system can further comprise a light source. A light source can be particularly advantageous when the at least one sensor includes a video camera or other video monitoring device due to the darkness of the interior of the structural cavity. The sensors of the sensing system can collect sensor input (e.g., acoustic input, temperature, humidity, vibrations, etc.) during wind turbine operation or when the wind turbine is parked (i.e., the blades are not rotating). In some aspects, particularly when more than one sensor is employed in the sensing system, the sensor input can be combined with sensor input from additional sensors in the system or from a separate sensing system when more than one system is employed within a single blade wind turbine to create a combined sensor input for the wind turbine or wind turbine blade.

[0032] In some aspects, the sensing system can have a fixed position within the structural cavity of the wind turbine blade. For example, the sensing system can be affixed to the internal blade surface. Affixing the sensing system can be by chemically, mechanically, or magnetically affixing, for example using an adhesive, physical attachment to the surface (e.g., with bolts), using a vacuum, suction cups, a magnet, velcro, or an air flow effective to generate a pressure sufficient to affix the sensing system to the surface.

[0033] In some aspects, more than one sensing system can be disposed in the wind turbine blade. Advantageously, employing more than one sensing system may allow for more effective monitoring, for example by conferring the ability to locate the position of any damage on the blade. When more than one sensing system is present and each sensing system is affixed to the internal surface, the sensing systems are preferably distributed within the structural cavity, for example distributed along the length of the structural cavity. The sensing systems may be, but are not required to be, evenly distributed (i.e., distributed such that there is an equal distance between adjacent sensing systems).

[0034] In some aspects, the sensing system can be capable of traveling or moving within the structural cavity. For example the sensing system may be a robotic sensing system capable of autonomous or self-directed movement within the structural cavity. Employing a movable sensing system in the structural cavity may preclude the need for multiple sensing systems to be used, for example in contrast to when stationary systems are used. Stated another way, an advantage to a movable sensing system is that the movable sensing system can be capable of obtaining sensor input data from various locations within the turbine blade without the need for multiple systems. When the sensing system is movable, the sensing system can further comprise a GPS denied-obstacle avoidance navigation autopilot. As used herein, the term “GPS-denied obstacle avoidance navigation autopilot” refers to an autonomous flight control system configured to navigate and avoid obstacles in environments where Global Positioning System (GPS) signals are unavailable, degraded, or intentionally obstructed. The system operates without reliance on GPS by utilizing alternative positioning and sensing modalities, such as inertial measurement units (IMUs), optical flow, LiDAR, radar, vision-based systems, or other onboard sensors, to detect and map obstacles, determine location, and execute real-time navigation and collision avoidance maneuvers.

[0035] Facilitating movement of the sensing system is not particularly limited. In an aspect, the sensing system can be guided by a track. The track, when present, can be affixed to the internal surface and can have a predefined route through the structural cavity. Any track can generally be used, for example a rack and pinion type track. In some aspects, the sensing system can be movably affixed to the internal surface and capable of traveling along the internal surface. The term “movably affixed” as used herein means that the sensing system is attached to the internal surface by means that allow for the sensing system to move along the internal surface (i.e., maintaining contact with the internal surface). For example, the sensing system may be movably affixed by a vacuum, suction cups, magnets, or an air flow effective to generate a pressure to affix the sensing system to the internal blade surface.

[0036] In some aspects, the sensing system can be configured to travel within the structural cavity using a motorized pulley and cable. It will be understood that the sensing system need not necessarily be affixed to the internal surface when a cable and pulley are used. Depending on placement of the cable and pulley, the sensing system may move along (but not necessarily in contact with) the internal surface or the sensing system may be suspended in an interior space of the structural cavity.

[0037] In some aspects, the sensing system can be configured to travel throughout the structural cavity by flying. For example, in some aspects the sensing system can be an autonomous aerial vehicle (e.g., a drone) having the at least one sensor. In some aspects, the sensing system can further include flight control configured to navigate all chambers of the structural cavity of the wind turbine blade and optionally pass through a hub of a wind turbine to inspect all wind turbine blades.

[0038] Since the sensing system of the present disclosure is disposed in a wind turbine blade which is not easily accessible, the sensing system is preferably rechargeable, battery operated, self-powered through energy harvesting, or wired. In some aspects, the sensing system is rechargeable, and the system may further comprise at least one sensing node in the structural cavity, for example affixed to the internal blade surface. Thus in some aspects, each wind turbine blade may include a distributed set of sensing nodes that can be rechargeable, battery operated (> 1 year life), self-powered through energy harvesting, or wired. The nodes can sense, record, and transmit data with on board processing to detect and assess damage. The sensing nodes can also have onboard damage or anomaly detection and signal notification. The sensing nodes can also have adaptive energy aware low power sensing and management. In some aspects, the sensing node can optionally further comprise one or more additional sensors to aid in anomaly detection and notification.

[0039] In some aspects, the sensor node may be a docking station or charging station, or may be capable of wirelessly charging the sensing system. In some aspects, the sensing node may be wired to an electrical source, for example through a cable that extends through the surface of the wind turbine blade and, for example, to the hub of the wind turbine or to an energy harvester on an external surface of the wind turbine blade. In some aspects the sensing node may be powered wirelessly, for example through induction through the surface of the wind turbine blade. In this embodiment, the power source located at the external surface of the wind turbine blade may be powered by wired connection to the hub of the wind turbine. In some embodiments, the power source may be self-powered, for example through energy harvesting (e.g., solar, wind). In addition to provided power to the sensing system, the sensing node canoptionally facilitate the transfer of data wirelessly, or while the sensing system is in contact with the sensing node for charging.

[0040] In some aspects, the system can further comprise a strain-sensing fiber or conductive fiber array sensing system connected to the at least one sensing node and on a surface of the cavity structure. The sensing node can therefore further be configured to detect deviations in a voltage level of strain-sensing fiber or conductive fiber array whereby strain, damage, or cracks are detected in the wind turbine. For example, if the blade skin is strained, damaged, or cracked, the overall system voltage level will deviate from its baseline. This deviation could be used as an additional cavity structure skin damage detection approach to identify excessive strain or cracking.

[0041] In some aspects, an external sensing system can be used in conjunction with the sensing system disposed within the wind turbine blade. For example, in some aspects, the structural health monitoring system can further comprise an external sensing system affixed to an external surface of the wind turbine. The external sensing system can be stationary, and can be affixed by chemical (e.g., adhesive) or mechanical (e.g., bolts) means. The external sensing system has at least one sensor for detecting and recording anomalies in the wind turbine, and a transmitter configured to transmit recorded anomalies to the receiver. The sensor can be as described above for the sensing system disposed in the structural cavity. In some aspects, the sensor may be a vibration sensor. In an aspect, the external sensing system can comprise an accelerometer. The accelerometer located in a blade-external sensor may be used to monitor tower vibrations / health and aid in damage location identification.

[0042] The sensor input received by the external sensing system can be transmitted to the same receiver as the internal sensing system (e.g., the centralized computing system).

[0043] It will also be appreciated that the sensing system disclosed herein may be used in other applications, particularly where monitoring acoustics, vibrations, temperature, humidity, or the like is needed, and more particularly, where the monitoring is needed in an enclosed or difficult-to-access space. In an aspect, the structural health monitoring system described herein may be used to monitor structural health of a nacelle of a wind turbine, a tower of a wind turbine, or both. A structural health monitoring system for a nacelle or tower of a wind turbine can comprise at least one sensor for detecting and recording anomalies in the wind turbine, and a transmitter configured to transmit recorded anomalies to the receiver. The at least one sensor of the structural health monitoring system for a nacelle or tower of a wind turbine can be as already described herein. The nacelle or tower monitoring system may be fixed or moveable within the nacelle or the tower of the wind turbine. All variations discussed herein in the context of thewind turbine blade also apply to the monitoring of structural health of a wind turbine nacelle or tower. In a specific aspect, the nacelle or tower monitoring system can be particularly useful for monitoring the bolted connections (e.g., the bolts and the bolt inserts) securing the blade root to the hub of the wind turbine.

[0044] In some aspects, the structural health monitoring system for the wind turbine blade can be used in combination with a structural health monitoring system for the nacelle or tower of the wind turbine.

[0045] In an aspect of the present disclosure, the structural health monitoring system can comprise a plurality of sensing systems, for example including one or more audio-visual sensing systems that can autonomously move back-and forth inside the blade cavity following a predefined path with mechanical guides (rails) or freely using wheels, a suction surface, or flight. Battery-operated miniature wireless charging stations (i.e., nodes) can optionally be chemically or mechanically bonded on the internal walls / surfaces of the cavity structure. In an aspect, the sensing systems can approach and wirelessly recharge themselves using these charging stations. The charging stations are stationary, and each station includes a rechargeable battery that can be replaced by the technician in every maintenance cycle (usually once a year). In some aspects, the railed configuration may be powered via electrical power cables. The end of the rails close to the blade close-out can have a charging station that sensing systems can approach and recharge autonomously. The data collected by the sensing systems can be stored on an SD-drive locally or be transferred wirelessly to a base station located inside the hub or elsewhere remote such as the base of the wind turbine tower. Alternatively, miniature drones can be used to transfer the data at a certain predefined frequency (for example, once a month). Similarly, miniature sensing robots can also be used to autonomously inspect the cavity structure from inside and / or outside. The blade-internal charging stations may include a piezoelectric, electro-magnetic gravity -based, solar, or other type of energy harvesting systems to minimize the need for maintenance and battery replacement. The system described herein provides an autonomous distributed sensing approach. Each sensor can have local data processing for fast onboard self-anomaly detection which will be used to identify the most useful frequency ranges (e.g., sample at lower frequencies or certain band-limited high frequencies) and sensors to save power and optimize damage detection. Only the sensors that are contributing to damage detection will be powered, whereas the other will go into their sleep mode to save power and limit the amount of data collected to help avoid collecting unnecessary data or wasting power. Consequently, the system described herein enables adaptive energy-aware low-power sensing. Each sensing unit may include not only one or multiple acoustic microphones for audiodetection but may also include a low-cost camera equipped with a fish-eye lens that can see the surrounding and take wide-angle optical pictures or thermal images that can be stitched using structure from motion rendering type algorithms to help inspect the cavity. The robot, drone, and fixed sensor nodes may also include other types of sensors (e.g., accelerometers, thermal IR sensors, strain sensors, temperature sensors, humidity sensors, electrical conductivity sensors). A low-energy light beam can be used to help take images inside the relatively dark internal sections of the cavity structure.

[0046] Referring to FIG. 1, an embodiment of the wind turbine blade and internal cavity structural health monitoring system is shown generally. The system includes a number of different features that are used to detect damage within a wind turbine blade or cavity. The system may include a sensing drone that can fly within each cavity of the blade or multiple blades to perform inspection. The drone can perform inspection when the rotor is spinning or when the turbine is not operating. The drone flight control allows it to navigate all chambers of a wind turbine blade and pass through the hub to other blades to inspect all turbine blades in the rotor. Also shown are audio-visual sensing robots capable of moving along the length of the blade. Also shown are various nodes which may be docking stations or able to facilitate noncontact charging.

[0047] In one embodiment, a sensing system that can be guided by a track (FIG. 2) or can stick itself and move along the walls or the floor of the structural cavity structure using a vacuum, suction cups, magnets, an air flow to generate a pressure to adhere it to the walls, or the like. The sensing system can also be moved along the blade length using a motorized pulley and cable / rope or be self-powered.

[0048] Referring to FIG. 3, an embodiment of a sensor system is shown. In this embodiment, there are no fasteners direct to the turbine walls and adhesives are used where possible in accordance with DNVGL-DNV-DS-J102, Sec 2. D. Generally outlined load cases from IEC 61400-3-1, 7.4 aided in examining what forces are experienced by the turbine blade. A motor connects to a gear reducer, in turn driving a shaft and a pinion gear, which propels the sensing system along a rack attached to the internal cavity of the wind turbine blade. The use of the gear reducer prevents the shaft from back turning and the fixture turning out of place. This means that stopping is achieved without the use of power or a mechanically compressed brake saving energy. A guide wheel may be included to keep the sensing system aligned on the rack. The sensing system may be configured to connect with a charging dock.

[0049] Referring to FIG. 4, another embodiment of a sensing system is shown. This embodiment demonstrates locking capabilities in which the sensing system was locked firmly inplace when the motor was not turning. The meshing between rack and pinion was enough to lock the cart in place without using any auxiliary power to the motor. This prototype iteration verified that the primary components of the mechanism worked as designed.

[0050] Referring to FIG. 5(a) and 5(b), an alternative embodiment of a sensing system has improved mass distribution. A sensor is locked in place using a cartridge shown on the top section of the embodiment. The cartridge helps with easy maintenance and replacement of the sensor assembly during a maintenance cycle of the sensing system.

[0051] Referring to FIG. 6, a structural health monitoring system is shown according to an embodiment of the present disclosure, wherein a sensing system is disposed in a turbine blade cavity, and an external sensing system is also present on the exterior of the wind turbine. In the embodiment shown, the turbine blades can generate acoustic radiation which can be detected by the internal and the external sensors to monitor for anomalies. While acoustic radiation is mentioned, other types of sensors capable of receiving different inputs (e.g., temperature, humidity, etc.) can be envisioned.

[0052] Therefore, it can be seen that the wind turbine blade and internal cavity structural health monitoring system disclosed herein, provides an inexpensive, in-situ, effective method to detect damage in the form of holes, cracks and leading / trailing edge splits in bonded surfaces, delamination, disbonds, lightning strike damage, water intrusion, icing, erosion as well as any other physical sources that may create acoustic or visual aberrations in the system.

[0053] A limiting factor to widespread use of sensors inside operational wind turbine blades, such as those described herein, is the long cables needed to transfer the power from the hub down to each sensor in each rotating blade structure. The present inventors have therefore discovered an energy harvester capable of supplying power to a sensor disposed within a wind turbine blade.

[0054] Accordingly, another aspect of the present disclosure is a vortex generation-based energy harvester for a wind turbine blade. The energy-harvester comprises a generator configured to generate power, and an air turbine comprising at least one blade operatively connected to the generator. The energy harvester, also referred to herein as a wind harvester, can be positioned on an outer surface (e.g., on the blade skin) of a wind turbine blade to generate a vortex as air flows over the outer surface of the wind turbine blade. In some aspects, the energy harvester may be on or near a leading edge of the wind turbine blade. In some aspects, the energy harvester may be at a mid-position on the wind turbine blade (e.g., approximately half way between the leading edge and the trailing edge of the blade. In some aspects, the energy harvester may be on or near a trailing edge of the wind turbine blade. For example, an energyharvester “near” a leading edge refers to the energy harvester being at a location on the wind turbine blade that is positioned within the forward portion of the blade surface, generally within the first 10% to 25% of the chord length (i.e., the straight-line distance between the leading edge and the trailing edge of a wind turbine blade cross-section, measured in the direction of the airflow) measured from the leading edge toward the trailing edge. Conversely, an energy harvester “near” a trailing edge refers to the energy harvester being at a location on the wind turbine blade that is positioned generally within the last 10% to 25% of the chord length (i.e., the straight-line distance between the leading edge and the trailing edge of a wind turbine blade cross-section, measured in the direction of the airflow) measured from the leading edge toward the trailing edge.

[0055] The generator of the energy harvester is configured to convert mechanical energy (i.e., rotational motion) into electrical energy for the purpose of energy harvesting. When the air turbine is rotated (i.e., as air flows through it), the generator generates a current (e.g., DC or AC current). The air turbine can include any suitable number of blades connected to the motor generator. In some aspects, the air turbine may comprise at least 2 blades. In some aspects, the air turbine may comprise a plurality of blades. In some aspects, the air turbine can comprise up to 50 or more blades. In a specific aspects, the air turbine may comprise 2 to 50 blades, or 2 to 40 blades, or 4 to 35 blades, or 2 to 20 blades, or 2 to 10 blades, or 2 to 5 blades.

[0056] The blades can generally be of any suitable thickness, inner diameter, and outer diameter, and can be readily determined by the skilled person based on the size of the air turbine, the amount of power to be generated, etc., and guided by the present disclosure.

[0057] In some aspects, it may be advantageous to contain the energy harvester within a housing, as this may protect the air turbine blades from damage due to being positioned on the exterior of a wind turbine blade. The housing is a structural enclosure configured to support, protect, and position the energy harvester within an airflow environment, such as that on a wind turbine blade. The housing is further configured to direct and manage air movement through the energy harvester components, and may provide mounting interfaces for associated hardware including shafts, bearings, and electrical generators.

[0058] The energy harvester can have either a horizontal or vertical orientation. For example, in some aspects, the blade of the air turbine can move about a central axis of the air turbine, wherein the central axis is parallel to the air flow over the out surface of the wind turbine blade (also referred to herein as “horizontal” or “propeller-type”). In some aspects, the blade of the air turbine can moves about a central axis of the air turbine and the central axis is perpendicular to the air flow over the outer surface of the wind turbine blade (also referred toherein as “vertical” or “impeller-type”).

[0059] One or more energy harvesters can be placed on the wind turbine blade. In some aspects, the number of energy harvesters can correspond to the number of sensing systems to be powered within the turbine. A short cable that is operatively connected to the energy harvester can transmit the generated power through the surface of the wind turbine blade to the sensors located inside the blade (i.e., through a drilled hole in the blades). Transmitting the power through the surface of with wind turbine blade wirelessly (e.g., via an inductive charger) is also contemplated. Advantageously, this can allow the sensors to be positioned anywhere that is feasible for an installing technician to access from within the blade. No high energy sources are needed, and long power cables and installation costs will also be alleviated. It is noted that while the energy harvesters of the present disclosure are specifically discussed in the context of power generation for sensors for wind turbine blades, the energy harvesters of the present disclosure could be used in other applications to provide power to a low-power device.

[0060] In some aspects, the energy harvester can be used in combination with a vortex generator. As used herein, the term “vortex generator” refers to an aerodynamic device configured to create controlled airflow vortices along the surface of a wind turbine blade. The vortex generator can improve airflow attachment, delay flow separation, and enhance aerodynamic performance, thereby increasing blade efficiency and reducing drag or noise. Vortex generators for wind turbines can include small fins, tabs, or vanes mounted on the blade surface, and may take forms such as triangular, rectangular, or trapezoidal shapes. These devices can be passive or active and are typically arranged in pairs or arrays to generate streamwise vortices that enhance boundary layer control and improve aerodynamic efficiency. When present, a vortex generator may be positioned such that the airflow from the vortex generator is directed into the energy harvester or the flow from the generator can be used to induce the vortex in the airflow surrounding the wind turbine blade.

[0061] Referring to FIG. 7, an energy harvester according to an aspect of the present disclosure is shown. The disclosed energy harvester positioned on the wind turbine in replacement of a prior art vortex -generator can accomplish energy generation for the sensors and simultaneously improved aerodynamic flow over the wind turbine blades. A four-blade turbine fan with a DC motor acting as a generator is shown in FIG. 7. The shroud (i.e., housing) for the turbine was designed around the size of the turbine blades and generator to effectively enclose the design, however, the shroud is optional and could be omitted. The number of blades on the turbine fan may be selected, including toroidal blades. Further, while a DC generator is selected to power DC sensors of a structural health monitoring system, an AC generator may be usedinstead to power AC sensors.

[0062] The testing results for the energy harvester shown in FIG. 7 matched predicted power generation within the limits of testing. The system used in testing with an airflow velocity of 15.1 meters per second (m / s) provided a power generation of 0.3828 watts (W), more than the needed 0.15 W. The main difference between the airflow in the test and the theoretical is that the air had not streamlined over an airfoil and developed a boundary layer before encountering the fan. Without a boundary layer the airflow was more intense and resulted in slightly better than expected power generation. Power production at more realistic air speeds were estimated to be approximately 8 W assuming an airspeed of 41.98 m / s and the wind turbine rotating at 10 rpm.

[0063] Another aspect of the energy harvester is shown in FIG. 8. FIG. 8 shows a vertical, impeller-type energy harvester disposed in a housing, compared to the horizontal, propeller-type energy harvester shown in FIG. 7.

[0064] Therefore, it can be seen that the presently disclosed vortex -based energy harvesting system solves the previous technical challenges by providing an energy harvesting mechanism suitable to powering structural health monitoring systems in wind turbine blades and simultaneously providing vortex-generation to the wind turbine blade to improve the efficiency and performance thereof. A significant improvement is therefore provided.

[0065] Another aspect of the present disclosure is a wind turbine blade. The wind turbine blade comprises an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin, and an energy harvester positioned on the outer surface and configured and arranged to generate a vortex as air flows over the outer surface of the wind turbine blade. The energy harvester is as already described herein.

[0066] FIG. 9 shows a side view of a wind turbine blade having an energy harvester on an outer surface. The energy harvester, also referred to as a wind harvester, can be configured to power a sensing system disposed in the interior cavity of the blade (e.g., internal microphones configured to detect acoustic anomalies). As shown in FIG. 9, the harvester can be configured to provide power to an internal sensing system by a wired connection through the surface of the blade. In other aspects not shown in FIG. 9, the harvester can be configured to wirelessly transmit power to an internal sensing system. As the wind flows over the blade having the harvester disposed thereon, flow over the surface can be disrupted due to the presence of the harvester, thereby creating a separation bubble (i.e., a region of recirculating air) as shown in FIG. 9.

[0067] Another embodiment of a wind turbine blade having an energy harvester disposed thereof is shown in FIG. 10. As shown in FIG. 10, the turbine blade can have one ormore harvesters positioned along the outer surface of the blade. Vortex generators can optionally be used, and may be positioned in front of the energy harvesters (i.e., towards the leading edge of the blade). The blade may have a sensing system disposed in the interior cavity of the blade (e.g., internal microphones configured to detect acoustic anomalies). As shown in FIG. 10, the harvester can be configured to provide power to an internal sensing system by a wired connection through the surface of the blade. In other aspects not shown in FIG. 10, the harvester can be configured to wirelessly transmit power to an internal sensing system.

[0068] A method of providing power to a structural monitoring system for a wind turbine blade is also disclosed. The wind turbine blade can have an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin. The method comprises providing an energy harvester according to the present disclosure. The energy harvester can be positioned on the outer surface of the wind turbine blade. Power can be generated using the energy harvester as air flows over the outer surface of the wind turbine blade.

[0069] The method can further comprise electrically connecting the energy harvester to provide power to the structural monitoring system within the wind turbine blade. The structural health monitoring system can be as described herein. For example, the structural health monitoring system can comprise a sensing system disposed in a structural cavity of the wind turbine blade, the sensing system having at least one sensor for detecting and recording anomalies in the wind turbine blade, and having a transmitter configured to transmit recorded anomalies to a receiver. All variations of the structural monitoring system described herein can be applied to the presently disclosed method.

[0070] In a specific aspect, a method of providing power to a structural monitoring system for a wind turbine blade is provided, the wind turbine blade having an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin. The method comprises providing an energy harvester comprising a generator configured to generate power; and an air turbine comprising at least one blade operatively connected to the generator; positioning the energy harvester on the outer surface; generating power with the energy harvester as air flows over the outer surface of the wind turbine blade; electrically connecting the energy harvester to provide power to the structural monitoring system within the wind turbine blade, the structural monitoring system comprising a sensing system disposed in a structural cavity of the wind turbine blade, the sensing system having at least one sensor for detecting and recording anomalies in the wind turbine blade, the sensing system having a transmitter configured to transmit recorded anomalies to a receiver.

[0071] This disclosure further encompasses the following aspects.

[0072] Aspect 1 : A structural monitoring system for a wind turbine blade, the wind turbine blade comprising an internal blade surface forming a structural cavity therein, and an external blade surface, the structural monitoring system comprising: a sensing system disposed in the structural cavity, the sensing system having at least one sensor for detecting and recording anomalies in the wind turbine blade, the sensing system having a transmitter configured to transmit recorded anomalies to a receiver.

[0073] Aspect 2: The system of aspect 1, wherein the sensing system is affixed to the internal blade surface.

[0074] Aspect 3: The system of aspect 1 or 2, comprising two or more sensing systems affixed to the internal blade surface, wherein the two or more sensing systems are distributed within the structural cavity.

[0075] Aspect 4: The system of any of aspects 1 to 3, wherein the sensing system is affixed to the internal blade surface chemically, mechanically, or magnetically.

[0076] Aspect 5: The system of any of aspects 1 to 4, wherein the sensing system is capable of traveling within the structural cavity.

[0077] Aspect 6: The system of any of aspects 1 to 5, wherein the sensing system is configured to travel within the structural cavity guided by a track.

[0078] Aspect 7: The system of any of aspects 1 to 6, wherein the sensing system is affixed to the internal blade surface and configured to travel within the structural cavity along the internal blade surface.

[0079] Aspect 8: The system of aspect 7, wherein the sensing system is movably affixed to the internal blade surface.

[0080] Aspect 9: The system of any of claims 1 to 8, wherein the sensing system is configured to travel within the structural cavity using a motorized pulley and cable.

[0081] Aspect 10: The system of any of aspects 1 to 9, wherein the sensing system is configured to travel within the structural cavity by flying within the structural cavity.

[0082] Aspect 11 : The system of any of aspects 1 to 10, wherein the sensing system is rechargeable, battery operated, self-powered through energy harvesting, or wired.

[0083] Aspect 12: The system of any of aspects 1 to 11, further comprising at least one charging station affixed to the internal blade surface.

[0084] Aspect 13: The system of aspect 12, wherein the sensing system can transfer data and transmit power wirelessly or in contact with the charging station for recharging.

[0085] Aspect 14: The system of any of aspects 1 to 13, wherein the sensing systemfurther comprises a GPS denied-obstacle avoidance navigation autopilot, and wherein the sensing system is further configured and arranged to make observations during wind turbine operation.

[0086] Aspect 15: The system of any of aspects 1 to 14, where the sensing system includes flight control configured to navigate all chambers of the structural cavity of the wind turbine blade and optionally pass through a hub of a wind turbine to inspect all wind turbine blades.

[0087] Aspect 16: The system of any of aspects 12 to 15, wherein the least one charging station further comprises damage or anomaly detection and signal notification.

[0088] Aspect 17: The system of any of aspects 12 to 16, wherein the least one charging station further comprises adaptive energy aware low power sensing and management.

[0089] Aspect 18: The system of any of aspects 1 to 17, wherein the at least one sensor is an acoustic microphone, an accelerometer, a thermal IR sensor, a microwave or radar sensor, a strain sensor, a temperature sensor, a humidity sensor, a conductivity sensor, a vibration sensor, or a video camera.

[0090] Aspect 19: The system of any of aspects 1 to 18, where the sensing system comprises at least one acoustic microphone to detect acoustic source damage, direction, and location.

[0091] Aspect 20: The system of any of aspects 1 to 19, wherein the sensing system comprises an acoustic microphone, a temperature sensor, an accelerometer, and a vibration sensor.

[0092] Aspect 21 : The system of any of aspects 1 to 20, wherein the at least one sensor collects sensor input during wind turbine operation or when a rotor of the wind turbine is parked.

[0093] Aspect 22: The system of any of aspects 1 to 21, wherein the sensing system further comprises a light source.

[0094] Aspect 23: The system of any of aspects 12 to 22, further comprising a strainsensing fiber or conductive fiber array sensing system connected to the at least one charging station and on a surface of the cavity structure, the charging station further configured to detect deviations in a voltage level of strain-sensing fiber or conductive fiber array whereby strain, damage, or cracks are detected in the wind turbine.

[0095] Aspect 24: The system of any of aspects 1 to 13, further comprising an external sensing system affixed to an external surface of the wind turbine, the external sensing system having at least one sensor for detecting and recording anomalies in the wind turbine, and a transmitter configured to transmit recorded anomalies to the receiver.

[0096] Aspect 25: The system of any of aspects 1 to 24, further comprising a nacelle or tower sensing system disposed in a nacelle or tower of the wind turbine, the nacelle or tower sensing system having at least one sensor for detecting and recording anomalies in the wind turbine, and a transmitter configured to transmit recorded anomalies to the receiver.

[0097] Aspect 26: A vortex generation-based energy harvester for a wind turbine blade, the energy harvester comprising: a generator configured to generate power; an air turbine comprising at least one blade operatively connected to the generator; wherein the energy harvester on an outer surface of the wind turbine blade to generate a vortex as air flows over the outer surface of the wind turbine blade.

[0098] Aspect 27: The energy harvester of aspect 26, wherein the generator generates DC or AC current when the air turbine is rotated.

[0099] Aspect 28: The energy harvester of aspect 26 or 27, wherein the turbine blade comprises a plurality of blades.

[0100] Aspect 29: The energy harvester of any of aspects 26 to 28, wherein the energy harvester is disposed in a housing.

[0101] Aspect 30: The energy harvester of any of aspects 26 to 29, wherein the at least one blade moves about a central axis of the air turbine, and the central axis is parallel to the air flow over the outer surface of the wind turbine blade.

[0102] Aspect 31 : The energy harvester of any of aspects 26 to 29, wherein the at least one blade moves about a central axis of the air turbine, and the central axis is perpendicular to the air flow over the outer surface of the wind turbine blade.

[0103] Aspect 32: A wind turbine blade, comprising: an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin; and an energy harvester positioned on the outer surface and configured and arranged to generate a vortex as air flows over the outer surface of the wind turbine blade; wherein the energy harvester is according to any of aspects 26 to 31.

[0104] Aspect 33: A method of providing power to a structural monitoring system for a wind turbine blade, the wind turbine blade having an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin, the method comprising: providing an energy harvester according to any of aspects 26 to 31; and positioning the energy harvester on the outer surface; and generating power with the energy harvester as air flows over the outer surface of the wind turbine blade.

[0105] Aspect 34: The method of aspect 33, further comprising: electrically connecting the energy harvester to provide power to the structural monitoring system within the windturbine blade.

[0106] Aspect 35: The method of aspect 33 or 34, wherein the structural health monitoring system comprises a sensing system disposed in a structural cavity of the wind turbine blade, the sensing system having at least one sensor for detecting and recording anomalies in the wind turbine blade, the sensing system having a transmitter configured to transmit recorded anomalies to a receiver.

[0107] Aspect 36: A method of providing power to a structural monitoring system for a wind turbine blade, the wind turbine blade having an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin, the method comprising: providing an energy harvester comprising a generator configured to generate power; an air turbine comprising at least one blade operatively connected to the generator; positioning the energy harvester on the outer surface; generating power with the energy harvester as air flows over the outer surface of the wind turbine blade; electrically connecting the energy harvester to provide power to the structural monitoring system within the wind turbine blade, the structural monitoring system comprising a sensing system disposed in a structural cavity of the wind turbine blade, the sensing system having at least one sensor for detecting and recording anomalies in the wind turbine blade, the sensing system having a transmitter configured to transmit recorded anomalies to a receiver.

[0108] The systems and methods described herein can alternatively comprise, consist of, or consist essentially of, any appropriate steps or components herein disclosed. The systems and methods can additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any materials (or species), steps, or components, that are otherwise not necessary to the achievement of the function or objectives of the systems and methods.

[0109] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. “Combinations” is inclusive of blends, mixtures, alloys, reaction products, and the like. The terms “first,” “second,” and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms “a” and “an” and “the” do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. “Or” means “and / or” unless clearly stated otherwise. Reference throughout the specification to “an aspect” means that a particular element described in connection with the aspect is included in at least one aspect described herein, and may or may not be present in other aspects. The term “combination thereof’ as used herein includes one or more of the listed elements, and is open, allowing the presence of one or more like elements notnamed. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various aspects.

[0110] Unless specified to the contrary herein, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears.

[0111] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference.

[0112] While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.

Claims

CLAIMS1. A structural monitoring system for a wind turbine blade, the wind turbine blade comprising an internal blade surface forming a structural cavity therein, and an external blade surface, the structural monitoring system comprising: a sensing system disposed in the structural cavity, the sensing system having at least one sensor for detecting and recording anomalies in the wind turbine blade, the sensing system having a transmitter configured to transmit recorded anomalies to a receiver.

2. The system of claim 1, wherein the sensing system is affixed to the internal blade surface.

3. The system of claim 2, comprising two or more sensing systems affixed to the internal blade surface, wherein the two or more sensing systems are distributed within the structural cavity.

4. The system of claim 1, wherein the sensing system is affixed to the internal blade surface chemically, mechanically, or magnetically.

5. The system of claim 1, wherein the sensing system is capable of traveling within the structural cavity.

6. The system of claim 5, wherein the sensing system is configured to travel within the structural cavity guided by a track.

7. The system of claim 2, wherein the sensing system is affixed to the internal blade surface and configured to travel within the structural cavity along the internal blade surface, wherein the sensing system is movably affixed to the internal blade surface.

8. The system of claim 1, wherein the sensing system is configured to travel within the structural cavity using a motorized pulley and cable or wherein the sensing system is configured to travel within the structural cavity by flying within the structural cavity.

9. The system of claim 1, wherein the sensing system is rechargeable, battery operated, self-powered through energy harvesting, or wired.

10. The system of claim 1, further comprising at least one sensing node affixed to the internal blade surface, wherein the sensing system can transfer data and transmit powerwirelessly or in contact with the sensing node for recharging.

11. The system of claim 1, wherein the at least one sensor is an acoustic microphone, an accelerometer, a thermal IR sensor, a microwave or radar sensor, a strain sensor, a temperature sensor, a humidity sensor, a conductivity sensor, a vibration sensor, or a video camera.

12. The system of claim 11, wherein the sensing system comprises an acoustic microphone, a temperature sensor, an accelerometer, and a vibration sensor.

13. The system of claim 1, wherein the sensing system further comprises a light source.

14. The system of claim 1, further comprising an external sensing system affixed to an external surface of the wind turbine, the external sensing system having at least one sensor for detecting and recording anomalies in the wind turbine, and a transmitter configured to transmit recorded anomalies to the receiver; a nacelle sensing system disposed in a nacelle of the wind turbine, the nacelle sensing system having at least one sensor for detecting and recording anomalies in the wind turbine, and a transmitter configured to transmit recorded anomalies to the receiver; a tower sensing system disposed in a tower of the wind turbine, the tower sensing system having at least one sensor for detecting and recording anomalies in the wind turbine, and a transmitter configured to transmit recorded anomalies to the receiver or a combination thereof.

15. A vortex generation-based energy harvester for a wind turbine blade, the energy harvester comprising: a generator configured to generate power; an air turbine comprising at least one blade operatively connected to the generator; wherein the energy harvester is on an outer surface of the wind turbine blade to generate a vortex as air flows over the outer surface of the wind turbine blade.

16. The energy harvester of claim 15, wherein the energy harvester is disposed in a housing.

17. The energy harvester of claim 15, wherein the at least one blade moves about a central axis of the air turbine, and the central axis is parallel to the air flow over the outer surfaceof the wind turbine blade.

18. The energy harvester of claim 15, wherein the at least one blade moves about a central axis of the air turbine, and the central axis is perpendicular to the air flow over the outer surface of the wind turbine blade.

19. A wind turbine blade, comprising: an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin; and an energy harvester positioned on the outer surface and configured and arranged to generate a vortex as air flows over the outer surface of the wind turbine blade; wherein the energy harvester is according to claim 15.

20. A method of providing power to a structural monitoring system for a wind turbine blade, the wind turbine blade having an outer surface with a leading edge and a trailing edge opposite the leading edge, the outer surface covered in a blade skin, the method comprising: providing an energy harvester according to claim 15; and positioning the energy harvester on the outer surface; generating power with the energy harvester as air flows over the outer surface of the wind turbine blade; and electrically connecting the energy harvester to provide power to the structural monitoring system within the wind turbine blade; wherein the structural health monitoring system comprises a sensing system disposed in a structural cavity of the wind turbine blade, the sensing system having at least one sensor for detecting and recording anomalies in the wind turbine blade, the sensing system having a transmitter configured to transmit recorded anomalies to a receiver.

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