Device and method for limiting interactions between animals and built structures

Abstract

The invention relates to a device for limiting interactions between animals and a structure comprising rigid elements, the device comprising, on the surface of such a rigid element, at least one electroacoustic transducer (30) for transmitting mechanical vibrations at at least one frequency, in a motion perpendicular to the surface of this rigid element, each transducer being connected to this rigid element by a rigid connection (32, 33, 34) configured to transmit these mechanical vibrations to the surface of the rigid element, the mechanical energy transmitted into the rigid element of the structure being greater than the mechanical energy directly transmitted by the electroacoustic transducer into the surroundings of this rigid element, this rigid element diffusing these mechanical vibrations into the surroundings of the structure.

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION: DEVICE AND METHOD FOR LIMITING INTERACTIONS BETWEEN ANIMALS AND CONSTRUCTED STRUCTURES

[0003] Technical field of the invention

[0004] The present invention relates to a device and a method for limiting interactions between animals and constructed structures. It aims, in particular, to warn these animals and / or to scare them away from a structure which may cause danger to these animals and / or whose operation or use may be degraded by these animals.

[0005] The present invention applies, in particular, to keeping flying animals, in particular birds and bats, away from wind turbines which can injure or even kill them, and to keeping them away from buildings and photovoltaic panels which they can damage, in particular through their droppings.

[0006] State of the art

[0007] The interaction of animals with certain infrastructure can be a source of danger for these animals. For example, certain species of birds and bats can be killed by the movements of wind turbine blades.

[0008] Conversely, some species can damage existing structures or their uses. For example, the performance of photovoltaic panels can be affected by bird droppings that use these structures as resting places.

[0009] Several patents describe different solutions for keeping these animals away from structures with which they are likely to interact, so as to limit the risks caused by these interactions. Among these patents, the use of sounds is often described. These solutions consist of distributing sound emitters around or on the equipment to be protected. For example, patent US9125394B2 and patent application US20170127664A1 describe specific ultrasound emission systems (whistles, emitters fixed on bars outside the structure).

[0010] These devices have, at least for certain frequencies, a limited range and they present a certain complexity of installation on the structure or in its environment. Presentation of the invention

[0011] The present invention aims to remedy all or part of these drawbacks.

[0012] To this end, the present invention relates, according to a first aspect, to a device for limiting interactions between animals and a structure comprising rigid elements. This device comprises, on the surface of such a rigid element, an electro-acoustic transducer for emitting mechanical vibrations having at least one frequency, in a movement perpendicular to the surface of this rigid element, this transducer being connected to this rigid element by a rigid connection configured to transmit these mechanical vibrations to the surface of the rigid element, the mechanical energy transmitted in the rigid element of the structure being greater than the mechanical energy directly emitted by this electro-acoustic transducer in the environment of this rigid element, this rigid element diffusing these mechanical vibrations in the environment of the structure.

[0013] Thanks to these arrangements, each rigid element equipped with at least one electroacoustic transducer emits acoustic waves over its entire surface. Animals approaching any part of this rigid element therefore receive an audible signal warning them of the presence of this rigid element in order to scare them away. The invention takes advantage of the better propagation of certain frequencies in rigid materials, for example metals, certain composite materials or certain plastics than in the ambient environment, air or water, so that the sound waves are heard more uniformly by the animals in a volume surrounding the structure. For a tall structure, for example a building or a wind turbine, the implementation of the invention avoids the need to find high fixing points or to have access to the high exterior parts, access requiring ropes or cranes.

[0014] In embodiments, at least one electroacoustic transducer is integrally within a hollow rigid member.

[0015] Thanks to these provisions, it is not necessary to run cables outside the rigid element or from inside the rigid element to the outside of this rigid element. In the case of installation of the device in the mast of a wind turbine, it can be done from the inside of the mast using existing hoists, ladders and walkways and platforms.

[0016] In embodiments, the rigid connection comprises at least one magnet. This magnetic attachment avoids any drilling or modification of the rigid element with which the transducer is associated. This rigid connection is particularly applicable to rigid steel elements.

[0017] In embodiments, the rigid connection between at least one transducer and the rigid element to which this transducer is connected is configured to provide thermal conduction to evacuate the heat generated in the transducer towards the rigid element.

[0018] This embodiment is particularly suitable for rigid metal elements which are therefore good conductors of heat. The transducer is thus fixed to a rigid element ensuring at least part of the heat dissipation.

[0019] In embodiments, the transducer comprises a piezoelectric ceramic.

[0020] Such a crystal can generate high-power vibrations, for example of the order of two kilowatts.

[0021] In embodiments, at least one transducer is positioned on the surface of the rigid element to generate, for at least one vibration frequency emitted by the transducer, destructive interference at a predetermined connection point of the rigid element to an external element.

[0022] This avoids the exertion of high amplitude vibrations resulting from constructive interference on this connection point, vibrations which would be likely to damage this connection point.

[0023] In embodiments, the device which is the subject of the invention further comprises at least one system for detecting the proximity of at least one animal of a target species and an activation means configured to activate at least one transducer in the event of such detection.

[0024] In embodiments, the activation means is configured to adapt the emissions of the transducers according to the nature of the species of the animal detected by at least one detection system.

[0025] In embodiments, the activation means is configured to activate at least one transducer on the predetermined activity periods of the target species and / or depending on the presence of the detected target species.

[0026] In embodiments, the activation means is configured to activate a plurality of transducers depending on the position, relative to the structure, of the detected animal. In embodiments, the activation means is configured to activate a plurality of transducers at different oscillation frequencies resulting in acoustic flapping phenomena.

[0027] According to a second aspect, the present invention relates to a wind turbine comprising a device which is the subject of the invention.

[0028] According to a third aspect, the present invention relates to a photovoltaic installation, which comprises a device which is the subject of the invention.

[0029] According to a fourth aspect, the invention relates to a building, which includes a device which is the subject of the invention.

[0030] The advantages, aims and particular characteristics of this wind turbine, this photovoltaic installation and this building being similar to those of the device which is the subject of the invention, they are not recalled here.

[0031] Brief description of the figures

[0032] Other advantages, aims and particular characteristics of the invention will emerge from the following non-limiting description of at least one particular embodiment of the exercise bench which is the subject of the present invention, with reference to the appended drawings, in which:

[0033] Figure 1 represents, in perspective view, a wind turbine and positions for installing transducers of a device which is the subject of the invention,

[0034] Figure 2 represents, in perspective view, a first particular embodiment of a transducer of a device which is the subject of the invention,

[0035] Figure 3 represents, in perspective view, a second embodiment of a transducer of a device which is the subject of the invention,

[0036] Figure 4 shows, in perspective view, a wind turbine equipped with three transducers as shown in Figure 3,

[0037] Figure 5 represents, in the form of a block diagram, functions of a particular embodiment of the device which is the subject of the invention,

[0038] Figure 6 represents, in the form of a flowchart, steps for installing a device which is the subject of the invention on a wind turbine, and

[0039] Figure 7 shows, in section, vibrations carried by a rigid element. Description of the embodiments

[0040] In Figure 1, we observe preferential locations 21 to 26 of electromechanical transducers in the different rigid elements of a wind turbine 20. Location 21 is at the head of the rotor, also called “hub”, carrying the blades of the wind turbine 20. Location 22 is on the upper part of the nacelle of the wind turbine 20. Location 23 is on the lower part of the nacelle of the wind turbine 20. Location 24 is on a blade of the wind turbine 20. Locations 25 and 26 are on the mast of the wind turbine 20.

[0041] Each of these locations 21 to 26 is surrounded by a rigid element, so that the mechanical vibrations generated by an electromechanical transducer propagate in the structure of these different rigid elements before they are diffused into the ambient environment, here the atmosphere.

[0042] Locations 21 to 26 shown in Figure 1 are only indicative. Depending on the objectives and the structure of the wind turbine, the number of transducers can be reduced or, on the contrary, increased.

[0043] Thus, one or more transducers can be fixed inside the hub of the wind turbine or on the walls of the nacelle by choosing orientations allowing to create a wide coverage. In particular, the lower part of the nacelle can be used to reinforce the sound emissions between the ground and the volume stirred by the blades. The base 24 of the blades also constitutes a possible installation site intended to propagate the sound emissions in the volume stirred by the blades, whatever their position relative to the mast.

[0044] Fixing one or more transducers at blade height in the wind turbine mast is particularly advantageous because it diffuses sounds directly into the lower part of the volume stirred by the blades without having to place loudspeakers outside this very inaccessible area. This area is preferred in the case of wind turbines using a concrete mast which may present an obstacle to the propagation of transducer vibrations because the upper part of the mast is generally made of steel with good vibration transmission capacity. On wind turbines equipped with a steel mast, one or more transducers fixed at the bottom of the mast are likely to prevent or deter animals flying at low altitude from approaching the wind turbine where an increase in altitude by these animals may present a danger to them and / or to the wind turbine.Figure 2 shows a particular embodiment of a transducer 30 and its rigid connection to a rigid element of equipment to be protected, for example the wind turbine 20 illustrated in Figure 1.

[0045] Each transducer 30 comprises at least one vibrator (not shown) emitting vibrations perpendicular to the surface of the rigid element 31 (partially shown) under the action of an alternating electric current. Each vibrator can be electrodynamic, electrostatic, piezoelectric, electromechanical or use a combination of these technologies so as to produce mechanical vibrations of a single frequency or of different frequencies. The frequency and amplitude of the emitted vibrations can be constant or modulated over time so as to effectively induce the expected response of the animals of the target species, creating the least possible nuisance to the protected equipment, its users and the neighborhood.

[0046] In the ambient environment, these mechanical vibrations are diffused in the form of sounds, ultrasounds and infrasounds, depending on the frequency of the initial vibrations and the possible broadening of the band of these frequencies depending on their propagation in the rigid element which carries the transducer 30 and their transmission to the ambient environment from this rigid element.

[0047] A support, or housing, 32 ensures the protection of each such vibrator and its power cable 35 and the thermal dissipation of the heat produced by this vibrator. Rigid junctions 33 ensure the connection with the surface of the rigid element of the equipment to be protected. These rigid junctions 33 can be composed of helical metal springs as shown in Figure 2 or any other suitable elastic system, whatever the geometry, nature or composition (metal blade, elastomer block, or other). These rigid junctions 33 have the function of transmitting the mechanical vibrations from each vibrator to the surface of the rigid element 31, surface in which the transverse mechanical vibrations propagate, which has the effect of diffusing them into the ambient environment.

[0048] Fasteners 34 are made so as to fix the transducer 30 on the surface of the rigid element 31 without damaging it. On a steel surface, the use of magnets 34 is preferred. On resins, composite materials, plastics or non-magnetic metals, the fixing can be done using resins or glues. The supports can be adapted for fixing on existing fixing points (threads, lifting flanges or attachment point). The transducers 30 are connected to an alternating current generation and amplification system 52 (see figure 5) via the flexible cable 35. This system 52 has an analog input / output interface 56 and a digital input / output interface 57 so as to be controlled and interact with other systems in the wind turbine, return information and be remotely controllable.

[0049] Each ultrasonic vibrator is, for example, of the type used for piezoelectric ultrasonic welding of plastic, with a frequency between 15KHz and 40KHz, and a power between 500W and 3000W.

[0050] An ultrasonic vibrator is a device that realizes mutual conversion between electrical energy and mechanical energy (acoustic vibration) through the piezoelectric effect of a piezoelectric ceramic, and is amplified by front and rear radiation cover blocks of a housing that match the acoustic impedance. Since the housing is a passive device, it does not produce vibration itself, but transmits the input vibration after changing its amplitude, completing the impedance transformation. Once the transducer is connected to such a housing, the amplitude of the ultrasonic wave can be changed within a wide range. As long as the material strength is sufficient, the amplitude can thus change from 10 pm at the output of the piezoelectric ceramic to 100 pm at the output of the housing.

[0051] According to different designs, the main forms of ultrasonic transducer are column type, inverted horn type, steel back cover type or intermediate aluminum foil type.

[0052] In Figure 7, we observe a rigid element 31 subjected to a mechanical vibration generated by a vibrator 71. The arrow 72 represents the component of this vibration perpendicular to the plane tangent to the rigid element 31 at its stress point, that is to say the support point of the vibrator or at the support point of a support of the vibrator in contact with the rigid element.

[0053] The mechanical vibration 72 causes, on the one hand, an emission of a primary vibration in the ambient medium, in phase with the stress, directly opposite the stress point and, on the other hand, a diffusion of a transverse wave, represented by the arrow 73, in the rigid element 31. Each point of the rigid element receiving this transverse wave causes the emission of a secondary vibration 74 in the ambient medium. This secondary vibration is out of phase, relative to the primary vibration, due to the diffusion time of the transverse wave up to this point. The diffusion speed in the rigid element being greater than the speed of sound in the ambient medium, the combination of the primary wave 72 and the secondary waves 74 corresponds to a wave front, or wave surface, 75 of conical shape.The mechanical energy transmitted in the rigid element 31 of the structure is greater, and preferably at least ten times greater, than the mechanical energy directly emitted by the vibrator 71 in the environment of this rigid element.

[0054] With reference to Figures 1 and 2, the device which is the subject of the invention comprises, on the surface of a rigid element of the equipment to be protected, at least one electro-acoustic transducer for emitting mechanical vibrations. These mechanical vibrations have at least one frequency and a component perpendicular to the surface of this rigid element. The transducer is connected to the rigid element by a rigid connection configured to transmit these mechanical vibrations to the surface of the rigid element.

[0055] Preferably, at least one electroacoustic transducer is entirely inside a hollow rigid element.

[0056] Preferably, in the case of a rigid metallic element, the rigid connection between the transducer and the rigid element is configured to ensure thermal conduction to evacuate the heat generated in the transducer towards the rigid element.

[0057] In Figure 3, we see a steerable transducer 40, which comprises rigid elements 42 equipped with internal vibrators. The panel 40 protects the vibrators and their connections and serves as a heat sink. The phase shifts of the sound emissions between the rigid elements 42 can be adjusted to obtain a phase combination optimizing the directivity of the wavefront resulting from their combinations. This panel is mounted on fixing flanges 41 allowing optimization of its orientation.

[0058] Figure 4 is a schematic illustration of the locations of transducers similar to transducer 40 on a wind turbine 20 to occasionally supplement the range of transducers similar to transducer 30, in particular thanks to phase combination. Their use can increase the noise level in certain sectors of the volume stirred by the blades, in particular if it is necessary to use ultrasound at high frequencies to ensure the removal of bats sensitive to these frequencies. Transducers similar to transducer 40 are outside the rotor head (hub) of the wind turbine. They constitute additional transducers to the transducers mounted on the structure of the wind turbine, similar to transducer 30.

[0059] In variants, the wind turbine 20 only includes transducers similar to the transducer 40, outside the structure of the wind turbine.

[0060] The arrows 45 illustrated in FIG. 4 represent examples of directions of emission of sound vibrations, by transducers 40, in the ambient environment.

[0061] Figure 5 shows functions of a particular embodiment of the device 50 that is the subject of the invention. The functional modules 51 to 53 are interconnected. The surface transducers 30 are organized in modules 51 in groups emitting vibrations of the same frequency or in groups emitting different frequencies. A generator-amplifier 52 generates the signals to be emitted by the transducers 30. At least one module 53 includes transducers 40 emitting directly into the ambient environment that can be added to the system 50. The generator-amplifier module 52 has an analog input / output 56 and a digital input / output 57 as well as a power supply socket 58. The generator-amplifier module 52 operates autonomously according to a brightness measurement and a clock, for example, and informs other systems of its operating status.These two inputs / outputs 56 and 57 are configured according to the communication contexts of the equipment to be protected.

[0062] The description given below corresponds to an industrial wind turbine equipped to warn and repel birds and bats. The invention can be applied to other structures which may be, for example, wind turbines, towers, bridge stays, cable car cables, power lines, turbines, net or trawl elements whose presence, operation or functioning may present a danger to the target species.

[0063] These target species may be protected animals (birds, bats, cetaceans or others) and likely to be threatened by an interaction (collision, barotrauma, drowning) with a structure that may be equipped with the system and likely to react to the sound emissions produced by the system.

[0064] The target species may also be animals that may harm the operation, use, operation or integrity of a structure (birds, fish, etc.) or create other nuisances in the vicinity of the structure that may be equipped. The digital input / output interface is, in this embodiment, connected to a system 54 for detecting the proximity of at least one animal of a target species, via an activation means 55 configured to activate at least one transducer in the event of detection of proximity of such an animal.

[0065] The detection system 54 is of a known type, for example based on optical, thermal, infrared, sonar, radar image processing or their combination, sound processing, in particular ultrasound, and an automatic analysis system using for example machine learning and artificial intelligence algorithms.

[0066] Preferably, the activation means 55 is configured to adapt the emissions of the transducers 30 and / or 40 according to the nature of the species of the animal detected by at least one detection system 54. Alternatively or additionally, the activation means 55 is configured to activate at least one transducer 30 and / or 40 over the predetermined periods of activity of the target species, in particular in the case of migratory target species.

[0067] Preferably, the activation means 55 is configured to activate a plurality of transducers 30 and / or 40 depending on the position, relative to the equipment to be protected, of the detected animal.

[0068] In embodiments, the activation means 55 is configured to activate a plurality of transducers 30 and / or 40, at different oscillation frequencies resulting in acoustic beating phenomena.

[0069] Preferably, the activation means 55 is configured to not activate any transducers 30 and / or 40 emitting sound waves likely to be harmful to humans, in the event of detection of the presence of a human and depending on its position relative to the equipment to be protected. In particular, in the event of an operator entering the mast of a wind turbine, any transducer positioned inside this mast is preferentially deactivated. It is noted that the detection of the presence of an operator in the mast can be done by detecting the opening of an access door.

[0070] Figure 6 illustrates steps implemented for the installation of the device which is the subject of the invention on a wind turbine.

[0071] During a step 61, the installation is dimensioned, including the number of devices to be installed, the position of each device, the transmission frequency of each device and the transmission power of each device, as a function of the geometry, dimensions, materials and natural frequencies of each rigid element of the wind turbine, the target species likely to approach this wind turbine and the desired constructive or destructive flapping and interference. For example, at least one transducer is positioned on the surface of the rigid element to generate, for at least one vibration frequency emitted by the transducer, destructive interference on a connection point of the rigid element on another element.

[0072] During a step 62, the transducers are fixed to the rigid elements chosen to carry them. As indicated above, magnetic fixing on a rigid steel element and bonding on a concrete element are preferred.

[0073] Optionally, during a step 63, at least one vibration sensor is also fixed in the wind turbine and / or near the wind turbine, to carry out measurements of power, directivity and frequency of the emitted sound waves and, possibly, to adapt the power of the electrical signals received by the transducers. These vibration sensors comprise, for example, microphones.

[0074] During step 64, the wiring of the transducers and any sensors installed on the wind turbine or near it is carried out.

[0075] During a step 65, the transducers and sensors are connected to a control unit, such as that described with reference to figure 5.

[0076] During a step 66, a calibration of the device is carried out.

[0077] For the operation of the device which is the subject of the invention installed on a wind turbine, an operating mode is chosen, for example between (a combination of these modes being possible):

[0078] - A forced operating mode consisting of continuous operation of the transducers, to keep animals away from the target species,

[0079] - A predictive operating mode consisting of operation of the transducers during daily, annual periods or periods linked to external events, such as meteorology, temperature, local humidity,

[0080] - A reactive mode, in which the activity level of the target species is measured, for example by camera, radar and / or acoustic sensor, and the transducers are activated if proximity between an animal of a target species and the wind turbine is detected,

[0081] - A combined mode of predictive and reactive modes, - A mixed mode, in which different vibration emitters are combined: audible warning in certain conditions (strong wind for example) and regulation with possible stopping of the wind turbine blades, in other conditions (light wind for example) and

[0082] - A safety mode, interrupting the operation of the transducers in the presence of an operator in or near the wind turbine (proximity detection, door opening, maintenance mode activated on the wind turbine).

[0083] As noted above, phase differences between sound waves emitted by transducers can be used to steer wave planes and form focused sound beams on the detected animal.

[0084] Of course, several transducers can be combined to emit acoustic vibrations in several frequency ranges between 0 and 200 kHz, and, more particularly, between 10 kHz and 100 kHz.

[0085] As understood from the foregoing description, the present invention consists of using existing structures to propagate sounds, and / or ultrasounds and / or infrasounds, in the environment surrounding them, using transducers in contact with rigid elements of the existing structure. These sounds are propagated in these rigid elements before being diffused in the form of acoustic waves in the environment surrounding the equipment to be protected.

[0086] The invention thus creates a large emission surface, transmitting higher sound powers to the ambient environment without making any structural modifications to the equipment to be protected.

[0087] The frequencies of the emissions are defined according to their effectiveness in achieving the objective of alerting and / or driving away the target species while propagating optimally in the structure and the environment surrounding the structure, without threatening its integrity, and reducing nuisances to the neighborhood and non-target species.

[0088] It can be pure continuous frequencies or emitted in the form of a pulse, frequency incursion, noise or any sound recording of audible or non-audible frequencies.

[0089] The ambient environment may be either air or water. The equipped structures may be dangerous for certain animals or may be installations whose operation, exploitation, use or integrity may be threatened by the target species, their behavior or their droppings. For example, the device of the invention may emit infrasound to prevent birds, for example pigeons or seagulls, from landing on structures.

[0090] The invention can also be implemented to keep humans away, in order to protect open areas or buildings. The present invention particularly relates to a wind turbine, a photovoltaic installation, a work of art, an airport or a building, which comprises a device which is the subject of the invention.

Claims

CLAIMS 1. Device (50) for limiting interactions between animals and a structure (20) comprising rigid elements, characterized in that it comprises, on the surface of such a rigid element, at least one electro-acoustic transducer (30, 40) for emitting mechanical vibrations having at least one frequency, in a movement perpendicular to the surface of this rigid element, each transducer being connected to this rigid element by a rigid connection (32, 33, 34) configured to transmit these mechanical vibrations to the surface of the rigid element, the mechanical energy transmitted in the rigid element of the structure being greater than the mechanical energy directly emitted by this electro-acoustic transducer in the environment of this rigid element, this rigid element diffusing these mechanical vibrations in the environment of the structure.

2. Device (50) according to claim 1, in which at least one electroacoustic transducer (30) is entirely inside a hollow rigid element.

3. Device (50) according to one of claims 1 or 2, in which the rigid connection (32, 33, 34) comprises at least one magnet (34).

4. Device (50) according to one of claims 1 to 3, in which the rigid connection (32, 33, 34) between at least one transducer and the rigid element to which this transducer is connected is configured to ensure thermal conduction for evacuating the heat generated in the transducer towards the rigid element.

5. Device (50) according to one of claims 1 to 4, in which the transducer (30, 40) comprises a piezoelectric ceramic.

6. Device (50) according to one of claims 1 to 5, in which at least one transducer (30, 40) is positioned on the surface of the rigid element to generate, for at least one vibration frequency emitted by the transducer, destructive interference on a predetermined connection point of the rigid element on an external element.

7. Device (50) according to one of claims 1 to 6, which further comprises at least one system (54) for detecting the proximity of at least one animal of a target species and an activation means (55) configured to activate at least one transducer (30, 40) in the event of such detection.

8. Device (50) according to claim 7, in which the activation means (55) is configured to adapt the emissions of each transducer (30, 40) according to the nature of the species of the animal detected by at least one detection system.

9. Device (50) according to one of claims 7 or 8, wherein the activation means (55) is configured to activate at least one transducer (30, 40) over the predetermined activity periods of the target species and / or depending on the presence of the detected target species.

10. Device (50) according to one of claims 7 to 9, wherein the activation means (55) is configured to activate a plurality of transducers (30, 40) depending on the position, relative to the structure, of the detected animal.

11. Device (50) according to one of claims 7 to 10, wherein the activation means (55) is configured to activate a plurality of transducers (30, 40) at different oscillation frequencies resulting in acoustic beating phenomena.

12. Wind turbine (20), which comprises a device (50) according to one of claims 1 to 11.

13. Photovoltaic installation, which comprises a device (50) according to one of claims 1 to 11.

14. Building, which comprises a device (50) according to one of claims 1 to

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