Bionic flapping wing type composite energy collector

Abstract

The embodiment of the invention relates to the technical field of energy collection, in particular to a bionic flapping wing type composite energy collector, which comprises a fixed seat, which is used for being fixed at an energy collection position and is internally provided with a cavity; the coil is fixed on the surface of the fixed seat and is arranged around the cavity; the magnet is located in the cavity, and the size of the magnet on the axis of the coil is smaller than the size of the cavity on the axis; the main wing spar is in a plate shape, one end of the main wing spar is fixed to the fixing base, the main wing spar extends in the direction away from the fixing base, and the extending direction of the main wing spar is perpendicular to the plate face of the main wing spar; the auxiliary spar is plate-shaped, and one end of the auxiliary spar is fixed with one end, far away from the fixed seat, of the main spar; and the piezoelectric plate is attached to and fixed to the plate surface of the main spar. According to the bionic flapping wing type composite energy collector provided by the embodiment of the invention, multi-directional vibration energy can be captured, and the energy collection effect of the composite energy collector in complex vibration environments such as bridges and freight trains is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of energy harvesting technology, and in particular to a bionic flapping-wing composite energy harvester. Background Art

[0002] A piezoelectric and electromagnetic composite energy harvester is a device that converts mechanical energy into electrical energy. It combines the piezoelectric effect and the electromagnetic induction principle to improve the efficiency of energy collection and the output power. Specifically, it uses piezoelectric ceramics to generate electric charge when subjected to mechanical stress, and uses magnets and coils to generate electromotive force during relative motion to collect energy.

[0003] At present, the existing composite energy collectors usually adopt a cantilever beam structure, in which a permanent magnet is fixed at one end of the piezoelectric cantilever beam. When the cantilever beam is stimulated to vibrate, the piezoelectric ceramic on the cantilever beam is deformed by force, which then generates electric charge, and the permanent magnet cuts the coil below to generate an induced electromotive force. However, the inventors of the present application found that the composite energy collector using the above structure (i.e., a permanent magnet is fixed at one end of the piezoelectric cantilever beam) can collect a relatively single source of vibration energy, and it is difficult to effectively capture multi-directional vibration energy. For example, its application in complex vibration environments such as bridges and freight trains has great limitations. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a bionic flapping-wing composite energy collector for capturing multi-directional vibration energy and improving the energy collection effect of the composite energy collector in complex vibration environments such as bridges and freight trains.

[0005] To achieve the above-mentioned effect, an embodiment of the present application provides a bionic flapping-wing composite energy collector, comprising: a fixed seat, configured to be fixed at an energy collection location, and having a cavity inside; a coil, fixed to the surface of the fixed seat, and arranged around the cavity; a magnet, located in the cavity, and its size on the axis of the coil is smaller than the size of the cavity on the axis; a main wing beam, in the shape of a plate, and one end of which is fixed to the fixed seat, and extends in a direction away from the fixed seat, wherein the extension direction of the main wing beam is perpendicular to the plate surface of the main wing beam; an aileron, in the shape of a plate, and one end of which is fixed to an end of the main wing beam away from the fixed seat, wherein the extension direction of the aileron is perpendicular to the plate surface of the aileron, and the plate surface of the aileron is arranged at an angle greater than 0° and less than or equal to 90° with the plate surface of the main wing beam; and a piezoelectric sheet, attached to and fixed to the plate surface of the main wing beam.

[0006] The embodiment of the present application provides a bionic flapping-wing composite energy collector. After the fixed base is fixed at the energy collection location, the fixed base is used as a vibration source. For example, the fixed base can be installed on a bridge, a building, or some special mechanical devices, and then the bridge, the building, or some special mechanical devices drive the fixed base to vibrate, thereby driving the main wing beam and even the aileron beam to vibrate through the fixed base; based on the coil being fixed to the surface of the fixed base and arranged around the cavity, and the magnet being located in the cavity, and its size on the axis of the coil being smaller than the size of the cavity on the axis, when the fixed base generates a larger amplitude due to vibration After a rapid deformation of a certain degree, the magnet will make a reciprocating oscillating motion in the cavity along the direction of the coil axis, thereby generating an electromotive force in the coil to collect energy through the coil; at the same time, based on the fact that the main wing beam is in the shape of a plate, and one end of which is fixed to the fixing seat and extends in a direction away from the fixing seat, when the fixing seat is subjected to a large rapid deformation due to vibration, the main wing beam will vibrate to a large extent, thereby causing the piezoelectric sheet that is attached to and fixed to the plate surface of the main wing beam to deform, and then causing the positive and negative charges of the piezoelectric sheet to move to both sides to generate charges, and then the charge on the piezoelectric sheet is collected through an energy collection harness electrically connected to the piezoelectric sheet. In addition, the main wing beam can also collect energy in the direction perpendicular to its plate surface to generate vibration, and indirectly make the magnet located in the fixed seat do reciprocating oscillation motion in the cavity along the direction of the coil axis, which can also make the piezoelectric sheet and the coil output electricity; more importantly, based on the fact that the auxiliary wing beam is plate-shaped and one end of it is fixed to the end of the main wing beam away from the fixed seat, the plate surface of the auxiliary wing beam and the plate surface of the main wing beam are set at an angle greater than 0° and less than or equal to 90°, so the auxiliary wing beam can also generate vibration by collecting energy perpendicular to the plate surface of the auxiliary wing beam that the main wing beam cannot collect, thereby driving the main wing beam to vibrate so that the piezoelectric sheet is deformed, and indirectly making the magnet located in the fixed seat do reciprocating oscillation motion in the cavity along the direction of the coil axis, which can also make the piezoelectric sheet and the coil output electricity.

[0007] In some embodiments, the aileron beam extends in a direction away from the fixing seat, that is, the extension direction of the aileron beam is in the same direction and parallel to the extension direction of the main wing beam. In this way, the length of the entire flapping-wing cantilever beam is increased, that is, the main wing beam and the aileron beam extend in the same direction, so that the lengths of the two in the extension direction of the main wing beam are longer, which increases the flexibility of the entire flapping-wing cantilever beam system and makes the flapping-wing cantilever beam more likely to vibrate at a lower frequency. At this time, when the vibration frequency in the environment is relatively low, this design enables the system to match the low-frequency vibration source and effectively collect low-frequency vibration energy.

[0008] In some embodiments, the fixing seat includes: a fixed shaft, a connecting member and a fixing member; one end of the fixed shaft is configured to be fixed at an energy collection location, and the other end is fixed to the main wing beam, wherein a first cavity is provided inside the fixed shaft; the connecting member is fixed to the side outer wall surface of the fixed shaft and extends in a direction away from the fixed shaft; the fixing member is fixed to one end of the connecting member away from the fixed shaft, wherein a second cavity is provided inside the fixing member; the number of the coils is two, one of the coils is fixed to the outer peripheral surface of the fixed shaft and arranged around the first cavity, and the other of the coils is fixed to the outer surface of the fixing member and arranged around the second cavity, wherein the axes of the two coils are parallel to each other; the number of the magnets is two, one of the magnets is located in the first cavity, and the other of the magnets is located in the second cavity. In this way, when the fixing seat vibrates, the two magnets will vibrate in their respective cavities, and make the coils corresponding to the two magnets output electricity, thereby improving the effect of electromagnetic energy collection; at the same time, due to the setting of the connecting piece, the mutual interference between the two magnets can be reduced, ensuring that the electromagnetic systems formed by the two magnets and their respective corresponding coils can work effectively; in addition, through the setting of the connecting piece and the fixing piece, the coil located on the fixing piece can also be fixed more stably.

[0009] In some embodiments, the magnetic force of the magnet in the cavity of the fixed shaft is greater than the magnetic force of the magnet in the cavity of the fixed part. Since the vibration amplitude at the center of the fixed seat is more obvious, the magnet and coil at the center of the fixed seat (i.e., the magnet and coil at the fixed shaft) are used as the main electromagnetic energy collection point; and the magnet and coil at the fixed part are used as the secondary electromagnetic energy collection point; therefore, by making the magnetic force of the magnet in the cavity of the fixed shaft greater than the magnetic force of the magnet in the cavity of the fixed part, the magnet and coil at the fixed part can have little or no interference with the magnet and coil at the fixed shaft, thereby further reducing the interaction between the two magnets.

[0010] In some embodiments, the fixing member is located directly below the main wing beam. In this way, the space below the main wing beam can be used to set the connecting member and the fixing member, thereby reducing the projected area of ​​the bionic flapping-wing composite energy collector and improving the area utilization rate for fixing the bionic flapping-wing composite energy collector.

[0011] In some embodiments, the connector includes a connector end and a connector body that are sequentially arranged and connected along the extension direction thereof, wherein the cross-sectional area of ​​the connector end in the extension direction of the connector first gradually decreases and then gradually increases, and the cross-sectional area of ​​the connector body in the extension direction gradually decreases. In this way, while improving the structural strength of the fixing position of the connector and the fixed shaft, when the fixed shaft vibrates, the vibration energy can be better transmitted to the fixing member via the connector, which is then conducive to inducing the vibration of the magnet located in the fixing member, reducing the loss of vibration energy in the transmission process, that is, achieving a higher power output under the same vibration energy.

[0012] In some embodiments, the fixing seat, the coil, the magnet, the main wing beam, the aileron beam and the piezoelectric sheet form the composite energy collection component; the number of the composite energy collection components is two; the two composite energy collection components are symmetrically distributed, wherein the axes of the coils of the two composite energy collection components are parallel to each other, and the extension directions of the main wing beams of the two composite energy collection components are opposite.

[0013] In some embodiments, the bionic flapping-wing composite energy collector further includes: a connecting member, the two ends of which are respectively connected to one end of the fixing seat of each of the two composite energy collection components connected to the corresponding main wing beam. In this way, when the two composite energy collection components work together, the connecting member can ensure a firm connection between the two composite energy collection components, provide necessary mechanical support, and maintain the stability and integrity of the structure.

[0014] In some embodiments, the connecting member is detachably connected to the two composite energy collection assemblies, such as by bolts and nuts. In this way, the flexibility of connecting the connecting member to the two composite energy collection assemblies can be improved, and if special circumstances are encountered, the single flapping wing can be disassembled to work alone.

[0015] In some embodiments, the connecting member is in the shape of a Chinese character "J", wherein the connecting member is provided with a groove or a through hole at the top of the Chinese character "J". In this way, by adjusting the stiffness and damping characteristics of the connecting member, the vibration frequency and amplitude of the flapping wing can be affected, the energy collection efficiency can be optimized, and at the same time, the material fatigue caused by repeated vibration can be reduced, thereby extending the service life of the system.

[0016] In some embodiments, the width of the main wing beam in the direction of its extension gradually increases; and / or the width of the auxiliary wing beam in the direction of its extension gradually increases. In this way, based on the bionic flapping wing principle, the energy collection efficiency of the main wing beam and / or the auxiliary wing beam when collecting energy perpendicular to their respective board surfaces can be improved.

[0017] In some embodiments, the bionic flapping-wing composite energy collector further includes: a mass block disposed at one end of the auxiliary wing beam away from the main wing beam. In this way, the resonance frequency of the main wing beam and the auxiliary wing beam can be further reduced, and the bandwidth of the vibration frequency collected by the main wing beam and the auxiliary wing beam can be further increased.

[0018] In some embodiments, the cavity is formed by a groove provided on the fixing seat, wherein the peripheral wall surface and the bottom wall surface of the groove are affixed with a first buffer cotton, and the notch of the groove is covered with a second buffer cotton. In this way, the wear of the magnet caused by vibration in the cavity can be reduced, and the service life of the bionic flapping-wing composite energy collector can be increased.

[0019] In some embodiments, the number of the piezoelectric sheets is two, and the two piezoelectric sheets are respectively attached to and fixed to the two plate surfaces of the main wing beam; and / or the thickness of the portion of the piezoelectric sheet close to the fixing seat is greater than the thickness of the portion of the piezoelectric sheet away from the fixing seat, and / or the piezoelectric sheet is arranged adjacent to the fixing seat. In this way, when the vibration energy of the main wing beam remains unchanged, the power output of the bionic flapping-wing composite energy collector can be increased.

[0020] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only used for the purpose of illustrating the preferred embodiments and are not to be considered as limitations of the present application. In addition, the same reference numerals are used throughout the drawings to represent the same components.

[0022] Figure 1 A schematic diagram of the structure of a bionic flapping-wing composite energy harvester (a single composite energy harvesting component) provided in some embodiments of the present application;

[0023] Figure 2 A structural exploded view of a bionic flapping-wing composite energy harvester (a single composite energy harvesting component) provided in some embodiments of the present application;

[0024] Figure 3 A structural exploded view of a portion of the structure of a bionic flapping-wing composite energy harvester provided in some embodiments of the present application;

[0025] Figure 4A schematic diagram of the structure of a bionic flapping-wing composite energy harvester (two composite energy harvesting components) provided in some embodiments of the present application after removing some coils and magnets;

[0026] Figure 5 A simplified diagram of the model of the main wing beam vibration of the piezoelectric piece of the bionic flapping-wing composite energy harvester (single composite energy harvesting component) provided in some embodiments of the present application;

[0027] Figure 6 A graph showing the variation of voltage and electric power with frequency obtained by calculating a simplified model of the vibration of the main wing beam of a piezoelectric piece for a bionic flapping-wing composite energy harvester (a single composite energy harvesting component) provided in some embodiments of the present application;

[0028] Figure 7 A simplified diagram of the model of the aileron beam vibration of the piezoelectric patch of the bionic flapping-wing composite energy harvester (single composite energy harvesting component) provided in some embodiments of the present application;

[0029] Figure 8 A graph showing the variation of voltage and electric power with frequency obtained by calculating a simplified model of the vibration of the aileron beam of the piezoelectric sheet for the bionic flapping-wing composite energy harvester (single composite energy harvesting component) provided in some embodiments of the present application;

[0030] Fig. 9 Analytical images of the coil and magnet for the bionic flapping-wing composite energy harvester (single composite energy harvesting component) provided in some embodiments of the present application, wherein the x-axis is time, the y-axis is frequency, and the z-axis is vibration displacement;

[0031] Fig.10 A displacement potential diagram of a finite element simulation of a piezoelectric sheet for a bionic flapping-wing composite energy harvester (a single composite energy harvesting component) provided in some embodiments of the present application;

[0032] Fig.11 A voltage-power coordinate diagram of a finite element simulation of a piezoelectric sheet for a bionic flapping-wing composite energy harvester (a single composite energy harvesting component) provided in some embodiments of the present application;

[0033] Fig.12 , 13 A schematic diagram of a two-dimensional rotating body modeling for a coil and a magnet in a bionic flapping-wing composite energy harvester (a single composite energy harvesting component) provided in some embodiments of the present application;

[0034] Fig.14 , 15In the bionic flapping-wing composite energy collector (single composite energy collection component) provided in some embodiments of the present application, the vibration frequency is set to the resonant frequency for the coil and the magnet, and simulation is performed with time as the x-axis to obtain the voltage and current images and the voltage phase diagram for the resistor, wherein the resistance value is 1000 ohms, the number of coil turns is 2000, and the coil wire diameter is 0.25 mm.

[0035] The reference numerals in the specific implementation manner are as follows:

[0036] Fixed seat 110, cavity 111, fixed shaft 112, fourth connecting member 113, fixing member 114, first cavity 115, second cavity 116, connecting end 117, connecting body 118, coil 120, magnet 130, main wing beam 140, auxiliary wing beam 150, piezoelectric sheet 160, connecting member 170, mass block 180, first connecting member 101, second connecting member 102, third connecting member 103, fifth connecting member 104, first buffer cotton 105, second buffer cotton 106. DETAILED DESCRIPTION

[0037] The embodiment of the present application provides a bionic flapping-wing composite energy collector, comprising: a fixed seat, configured to be fixed at an energy collection location, and having a cavity therein; a coil, fixed to the surface of the fixed seat, and arranged around the cavity; a magnet, located in the cavity, and having a size on the axis of the coil smaller than a size of the cavity on the axis; a main wing beam, in the shape of a plate, and having one end fixed to the fixed seat, and extending in a direction away from the fixed seat, wherein the extension direction of the main wing beam is perpendicular to the plate surface of the main wing beam; an aileron, in the shape of a plate, and having one end fixed to an end of the main wing beam away from the fixed seat, wherein the extension direction of the aileron is perpendicular to the plate surface of the aileron, and the plate surface of the aileron is arranged at an angle greater than 0° and less than or equal to 90° with the plate surface of the main wing beam; and a piezoelectric sheet, attached to and fixed to the plate surface of the main wing beam.

[0038] The embodiment of the present application provides a bionic flapping-wing composite energy collector. After the fixed base is fixed at the energy collection location, the fixed base is used as a vibration source. For example, the fixed base can be installed on a bridge, a building, or some special mechanical devices, and then the bridge, the building, or some special mechanical devices drive the fixed base to vibrate, thereby driving the main wing beam and even the aileron beam to vibrate through the fixed base; based on the coil being fixed to the surface of the fixed base and arranged around the cavity, and the magnet being located in the cavity, and its size on the axis of the coil being smaller than the size of the cavity on the axis, when the fixed base generates a larger amplitude due to vibration After a rapid deformation of a certain degree, the magnet will make a reciprocating oscillating motion in the cavity along the direction of the coil axis, thereby generating an electromotive force in the coil to collect energy through the coil; at the same time, based on the fact that the main wing beam is in the shape of a plate, and one end of which is fixed to the fixing seat and extends in a direction away from the fixing seat, when the fixing seat is subjected to a large rapid deformation due to vibration, the main wing beam will vibrate to a large extent, thereby causing the piezoelectric sheet that is attached to and fixed to the plate surface of the main wing beam to deform, and then causing the positive and negative charges of the piezoelectric sheet to move to both sides to generate charges, and then the charge on the piezoelectric sheet is collected through an energy collection harness electrically connected to the piezoelectric sheet. In addition, the main wing beam can also collect energy in the direction perpendicular to its plate surface to generate vibration, and indirectly make the magnet located in the fixed seat do reciprocating oscillation motion in the cavity along the direction of the coil axis, which can also make the piezoelectric sheet and the coil output electricity; more importantly, based on the fact that the auxiliary wing beam is plate-shaped and one end of it is fixed to the end of the main wing beam away from the fixed seat, the plate surface of the auxiliary wing beam and the plate surface of the main wing beam are set at an angle greater than 0° and less than or equal to 90°, so the auxiliary wing beam can also generate vibration by collecting energy perpendicular to the plate surface of the auxiliary wing beam that the main wing beam cannot collect, thereby driving the main wing beam to vibrate so that the piezoelectric sheet is deformed, and indirectly making the magnet located in the fixed seat do reciprocating oscillation motion in the cavity along the direction of the coil axis, which can also make the piezoelectric sheet and the coil output electricity.

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, each embodiment of the present application will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in each embodiment of the present application, many technical details are proposed in order to enable the reader to better understand the present application. However, the technical scheme claimed in the present application can also be realized by various changes and modifications based on the following embodiments.

[0040] See also Figures 1 to 4In some embodiments, a bionic flapping-wing composite energy collector includes: a fixing seat 110, configured to be fixed at an energy collection location, and having a cavity 111 therein; a coil 120, fixed to a surface of the fixing seat 110, and arranged around the cavity 111; a magnet 130, located in the cavity 111, and having a size on the axis of the coil 120 smaller than that of the cavity 111 on the axis; a main wing beam 140, which is plate-shaped, and has one end fixed to the fixing seat 110, and is arranged along a direction away from the fixing seat 110. The main wing beam 140 extends in the direction of the fixed seat 110, wherein the extension direction of the main wing beam 140 is perpendicular to the plate surface of the main wing beam 140; the auxiliary wing beam 150 is plate-shaped, and one end of which is fixed to the end of the main wing beam 140 away from the fixed seat 110, wherein the extension direction of the auxiliary wing beam 150 is perpendicular to the plate surface of the auxiliary wing beam 150, and the plate surface of the auxiliary wing beam 150 and the plate surface of the main wing beam 140 are arranged at an angle greater than 0° and less than or equal to 90°; and the piezoelectric sheet 160 is attached to and fixed to the plate surface of the main wing beam 140.

[0041] After fixing the fixing base 110 at the energy collection location, the fixing base 110 is used as a vibration source. For example, the fixing base 110 can be installed on a bridge, a building, or some special mechanical devices, and then the bridge, the building, or some special mechanical devices drive the fixing base 110 to vibrate, thereby driving the main wing beam 140 and even the auxiliary wing beam 150 to vibrate through the fixing base 110.

[0042] It should be noted that the present application does not limit the energy collection location; for example, first, in the field of wind power generation, especially in the collection of urban environments and ocean wind, the wind direction is changeable and the wind force is unstable. The bionic flapping-wing composite energy collector of this embodiment can effectively collect energy from wind in different directions; second, monitoring equipment near bridges, roads or railways can utilize the vibration energy caused by passing vehicles. These vibration energies usually come from multiple directions. The bionic flapping-wing composite energy collector of this embodiment can effectively collect energy from vibrations in different directions; third, in an industrial environment, the operation of machines and equipment produces multi-directional vibrations. The bionic flapping-wing composite energy collector of this embodiment can effectively collect energy from vibrations in different directions, and these vibration energies can be used to power sensors and monitoring equipment; fourth, high-rise buildings or large structures will produce multi-directional vibrations under wind loads and earthquakes. The bionic flapping-wing composite energy collector of this embodiment can effectively collect energy from vibrations in different directions, and these vibration energies can be used to provide power for structural health monitoring systems.

[0043] Based on the fact that the coil 120 is fixed on the surface of the fixing base 110 and is arranged around the cavity 111, the magnet 130 is located in the cavity 111, and its size on the axis of the coil 120 is smaller than the size of the cavity 111 on the axis. Therefore, when the fixing base 110 undergoes a large and rapid deformation due to vibration, the magnet 130 will perform reciprocating oscillation motion in the cavity 111 along the axis of the coil 120, thereby generating an electromotive force in the coil 120 to collect energy through the coil 120.

[0044] It should be noted that the magnet 130 in the present application can be formed by several magnetic blocks. When the bionic flapping-wing composite energy collector is used, the collectible energy at the bionic flapping-wing composite energy collector can be analyzed, so as to increase or decrease the number of magnetic blocks and adjust the magnetic force of the magnet 130 to be more suitable for energy collection at the bionic flapping-wing composite energy collector.

[0045] Since the main wing beam 140 is in the shape of a plate and one end of it is fixed to the fixing seat 110 and extends in a direction away from the fixing seat 110, when the fixing seat 110 undergoes a rapid and large deformation due to vibration, the main wing beam 140 will vibrate to a large extent, thereby causing the piezoelectric sheet 160 that is attached to and fixed to the plate surface of the main wing beam 140 to deform, thereby causing the positive and negative charges of the piezoelectric sheet 160 to move to both sides to generate charges, and then the charges on the piezoelectric sheet 160 are collected through an energy collection harness electrically connected to the piezoelectric sheet 160.

[0046] In addition, the main wing beam 140 can also collect energy in a direction perpendicular to its panel surface to generate vibration, and indirectly make the magnet 130 located in the fixing seat 110 perform reciprocating oscillation motion in the cavity 111 along the axis direction of the coil 120, so that the piezoelectric sheet 160 and the coil 120 can also output electricity.

[0047] It should be particularly noted that, since the aileron beam 150 is plate-shaped and one end of the aileron beam 150 is fixed to the end of the main wing beam 140 away from the fixing seat 110, the plate surface of the aileron beam 150 and the plate surface of the main wing beam 140 are set at an angle greater than 0° and less than or equal to 90°, the aileron beam 150 can also generate vibration by collecting energy perpendicular to the plate surface of the aileron beam 150 that the main wing beam 140 cannot collect, and then drive the main wing beam 140 to vibrate so that the piezoelectric piece 160 is deformed, and indirectly make the magnet 130 located in the fixing seat 110 reciprocate in the cavity 111 along the axis of the coil 120. In this way, the piezoelectric piece 160 and the coil 120 can also output electricity. It should be supplemented that existing researchers have conducted in-depth research on the flapping flight mechanism of insects, birds and bats, and the flight ability of these creatures has always been the main imitation object of flapping-wing aircraft design. The research focuses include the lift mechanism of flapping wings, the influence of airfoil parameters and microstructure, wing flexibility, dynamic deformation, wing-wing interference, wing-body interference, inter-individual interference, and the influence of ground effect on flapping wing aerodynamics. When designing a bionic flapping-wing aircraft, the researchers designed a folding and flapping mechanism based on a crank-connecting rod in a bionic way, established a kinematic model of the flapping wing mechanism, and obtained relevant kinematic parameters. The dynamic model of flapping wings during flapping was derived by the Lagrangian method, which is helpful to analyze and improve the flight performance of flapping-wing aircraft. The aerodynamic force and aerodynamic moment load of the flapping wing were estimated based on the strip method, and the change law of the aerodynamic moment of the wing during the asymmetric flapping of the folded and flapped wings was analyzed. The results show that compared with the general straight flapping wing, the folded and flapped wing is subject to less resistance in the flapping stage, so it can obtain greater lift during the flapping process of the flapping wing. However, there is no application of flapping wing bionics in the field of energy harvesters.

[0048] The present application realizes the bionics of flapping wings through the main wing beam 140 and the auxiliary wing beam 150 and applies it to the energy collector, which can improve the energy collection effect of the energy collector.

[0049] In this embodiment, the size of the piezoelectric sheet 160 can be 30*18*0.3mm. The piezoelectric sheet 160 is encapsulated in a 53*20*1mm hard material shell, and the positive and negative leads are separately led out and welded, which can ensure its safety and stability during vibration. The piezoelectric sheet 160 can be made of PZT-5H.

[0050] In this embodiment, the coil 120 is made of 0.25 mm diameter copper wire, and the number of turns can be 1000 turns, 2000 turns, 3000 turns, etc. The magnet 130 can be a permanent magnet, specifically a neodymium iron boron magnet.

[0051] In this embodiment, a first connector 101 is provided on the fixing seat 110; the first connector 101 is provided with four through holes, and two through holes of the first connector 101 are used for screws to pass through and fix the first connector 101 on the fixing seat 110; a second connector 102 is provided between the first connector 101 and the main wing beam 140; two through holes are provided at the positions of the second connector 102 and the main wing beam 140 corresponding to the other two through holes of the first connector 101, so that the main wing beam 140, the second connector 102 and the first connector 101 can be fixed to each other by screws. Among them, at least one end of the second connector 102 can be rounded, and the rounded corner can make the assembly and disassembly process smoother, reduce damage or difficulties caused by sharp edges, especially when subjected to pressure or impact, to avoid stress concentration, so as to increase the stability of the component; the main wing beam 140 is connected to the auxiliary wing beam 150 through the third connector 103.

[0052] See also Figures 1 to 4 In some embodiments, the auxiliary spar 150 extends in a direction away from the fixing seat 110. Since one end of the auxiliary spar 150 is fixed to a section of the main spar 140 away from the fixing seat 110, and the main spar 140 extends in a direction away from the fixing seat 110, the extension direction of the auxiliary spar 150 can be in the same direction and parallel to the extension direction of the main spar 140.

[0053] In this way, the length of the entire flapping wing cantilever beam is increased, that is, the main wing beam 140 and the auxiliary wing beam 150 extend in the same direction, so that the lengths of the two in the extension direction of the main wing beam 140 are longer, and the flexibility of the entire flapping wing cantilever beam system is increased, making the flapping wing cantilever beam more likely to vibrate at a lower frequency. At this time, when the vibration frequency in the environment is relatively low, this design enables the system to match the low-frequency vibration source and effectively collect low-frequency vibration energy.

[0054] See also Figures 1 to 4In some embodiments, the fixing seat 110 includes: a fixing shaft 112, a fourth connecting member 113 and a fixing member 114; one end of the fixing shaft 112 is configured to be fixed to an energy collection location, and the other end is fixed to the main wing beam 140, wherein a first cavity 115 is provided inside the fixing shaft 112; the fourth connecting member 113 is fixed to a side outer wall surface of the fixing shaft 112 and extends in a direction away from the fixing shaft 112; the fixing member 114 is fixed to an end of the fourth connecting member 113 away from the fixing shaft 112, wherein a second cavity 116 is provided inside the fixing member 114; the number of coils 120 is two, one coil 120 is fixed to the outer circumference of the fixing shaft 112 and is arranged around the first cavity 115, and the other coil 120 is fixed to the outer surface of the fixing member 114 and is arranged around the second cavity 116, wherein the axes of the two coils 120 are parallel to each other; the number of magnets 130 is two, one magnet 130 is located in the first cavity, and the other magnet 130 is located in the second cavity.

[0055] In this way, when the fixing base 110 vibrates, the two magnets 130 will vibrate in their respective corresponding cavities 111, and make the coils 120 corresponding to the two magnets 130 output electricity, thereby improving the effect of electromagnetic energy collection; at the same time, due to the setting of the fourth connecting member 113, the mutual interference between the two magnets 130 can be reduced, ensuring that the electromagnetic systems formed by the two magnets 130 and their respective corresponding coils 120 can work effectively; in addition, through the setting of the fourth connecting member 113 and the fixing member 114, the coil 120 located on the fixing member 114 can also be fixed more stably.

[0056] In other embodiments not shown, there may be only one magnet in the fixing seat; a cavity may be provided in the aileron beam, and a coil may be provided on the aileron beam, wherein a magnet is provided in the cavity in the aileron beam; in this way, the effect of electromagnetic energy collection can also be improved.

[0057] See also Figures 1 to 4 In some embodiments, the magnetic force of the magnet 130 located in the cavity of the fixed shaft 112 is greater than the magnetic force of the magnet 130 located in the cavity of the fixed member 114 .

[0058] It should be noted that when the magnet 130 is formed by a plurality of magnetic blocks, the number of magnetic blocks located in the cavity of the fixed shaft 112 can be greater than the number of magnetic blocks located in the cavity of the fixing member 114, thereby achieving that the magnetic force of the magnet 130 located in the cavity of the fixed shaft 112 is greater than the magnetic force of the magnet 130 located in the cavity of the fixing member 114. Of course, in other embodiments, the magnetic force of the magnet located in the cavity of the fixed shaft is greater than the magnetic force of the magnet located in the cavity of the fixing member only by the difference in the magnetic force of the magnet itself. The present application does not limit the specific method for implementing this embodiment.

[0059] Since the vibration amplitude at the center of the fixed base 110 is more obvious, the magnet 130 and the coil 120 at the center of the fixed base 110 (that is, the magnet 130 and the coil 120 at the fixed shaft 112) are used as the main electromagnetic energy collection point; and the magnet 130 and the coil 120 at the fixing part 114 are used as the secondary electromagnetic energy collection point; therefore, by making the magnetic force of the magnet 130 located in the cavity of the fixed shaft 112 greater than the magnetic force of the magnet 130 located in the cavity of the fixing part 114, it can be achieved that the magnet 130 and the coil 120 located at the fixing part 114 have little or no interference with the magnet 130 and the coil 120 located at the fixed shaft 112, thereby further reducing the interaction between the two magnets 130.

[0060] See also Figures 1 to 4 In some embodiments, the fixing member 114 is located directly below the main spar 140. In this way, the space below the main spar 140 can be used to set the fourth connecting member 113 and the fixing member 114, thereby reducing the projected area of ​​the bionic flapping-wing composite energy collector and improving the area utilization rate for fixing the bionic flapping-wing composite energy collector.

[0061] See also Figures 1 to 4 In some embodiments, the fourth connector 113 includes a connector end 117 and a connector body 118 which are sequentially arranged and connected along the extension direction thereof, wherein the cross-sectional area of ​​the connector end 117 in the extension direction of the fourth connector 113 first gradually decreases and then gradually increases, and the cross-sectional area of ​​the connector body 118 in the extension direction thereof gradually decreases. The cross-sectional areas here refer to the cross-sectional area of ​​the connector end 117 in the direction perpendicular to the extension direction of the fourth connector 113 and the cross-sectional area of ​​the connector body 118 in the direction perpendicular to the extension direction of the fourth connector 113.

[0062] In this way, while achieving the improvement of the structural strength of the fixing position of the fourth connecting member 113 and the fixed shaft 112, when the fixed shaft 112 vibrates, the vibration energy can be better transmitted to the fixing member 114 via the fourth connecting member 113, thereby facilitating the vibration of the magnet located in the fixing member 114, thereby reducing the loss of vibration energy in the transmission process, that is, achieving higher power output under the same vibration energy.

[0063] See also Figure 4 In some embodiments, the fixing seat 110, the coil 120, the magnet 130, the main wing beam 140, the auxiliary wing beam 150 and the piezoelectric sheet 160 form a composite energy collection component; the number of the composite energy collection components is two; the two composite energy collection components are symmetrically distributed, wherein the axes of the coils 120 of the two composite energy collection components are parallel to each other, and the extension directions of the main wing beams 140 of the two composite energy collection components are opposite.

[0064] See also Figure 4 In some embodiments, the bionic flapping-wing composite energy collector further includes: a connecting member 170, both ends of which are respectively connected to one end of the fixing base 110 of each of the two composite energy collection components connected to the corresponding main wing beam 140. In this way, when the two composite energy collection components work together, the connecting member 170 can ensure a firm connection between the two composite energy collection components, provide necessary mechanical support, and maintain the stability and integrity of the structure.

[0065] Furthermore, in some embodiments, the connection member 170 and the two composite energy collection components are detachably connected, such as by bolts and nuts. In this way, the flexibility of the connection between the connection member 170 and the two composite energy collection components can be improved, and if a special situation occurs, the single flapping wing can be disassembled to work alone.

[0066] Furthermore, in some embodiments, the connecting member 170 is in a "J" shape, wherein the connecting member 170 is provided with a groove or a through hole at the top of the "J" shape. Thus, by adjusting the stiffness and damping characteristics of the connecting member 170, the vibration frequency and amplitude of the flapping wing can be affected, the energy collection efficiency can be optimized, and the material fatigue caused by repeated vibration can be reduced, thereby extending the service life of the system.

[0067] See also Figure 1 , Figure 2 , Figure 4 In some embodiments, the width of the board surface of the main spar 140 in its extension direction gradually increases; and / or the width of the board surface of the auxiliary spar 150 in its extension direction gradually increases. In this way, based on the bionic flapping wing principle, the energy collection efficiency of the main spar 140 and / or the auxiliary spar 150 when collecting energy perpendicular to their respective board surfaces can be improved.

[0068] See also Figure 1 , Figure 2 , Figure 4 In some embodiments, the bionic flapping-wing composite energy collector further includes: a mass block 180 disposed at one end of the secondary wing beam 150 away from the main wing beam 140. In this way, the resonance frequency of the main wing beam 140 and the secondary wing beam 150 can be further reduced, so that the bionic flapping-wing composite energy collector can respond to external excitation in a wider frequency range, and then further increase the bandwidth of the vibration frequency collected by the main wing beam 140 and the secondary wing beam 150. In this embodiment, the mass block 180 can be fixed to the secondary wing beam 150 through the fifth connecting member 104.

[0069] See also Figure 3In some embodiments, the cavity 111 is formed by a groove provided on the fixing seat 110, wherein the peripheral wall surface and the bottom wall surface of the groove are affixed with the first buffer cotton 105, and the notch of the groove is covered with the second buffer cotton 106. In this way, the wear of the magnet 130 caused by vibration in the cavity can be reduced, and the service life of the bionic flapping-wing composite energy collector can be improved. In addition, a card block can be provided on the outer periphery of the second buffer cotton 106, and a card slot can be provided at the position of the notch of the groove corresponding to the card block, and the card block can be embedded in the card slot, and the stability of the notch of the groove can be covered by the second buffer cotton 106.

[0070] In some embodiments, there are two piezoelectric sheets 160, and the two piezoelectric sheets 160 are respectively attached to and fixed on two surfaces of the main wing beam 140. In this way, when the vibration energy of the main wing beam 140 remains unchanged, the power output of the bionic flapping wing composite energy collector can be increased.

[0071] The thickness of the portion of the piezoelectric sheet 160 close to the fixing seat 110 is greater than the thickness of the portion of the piezoelectric sheet 160 far from the fixing seat 110, and / or the piezoelectric sheet 160 is disposed adjacent to the fixing seat 110. In this way, when the main wing beam 140 vibrates, the deformation amount of the main wing beam 140 close to the fixing seat 110 is larger, therefore, when the vibration energy of the main wing beam 140 remains unchanged, the power output of the bionic flapping-wing composite energy collector can be increased.

[0072] In some embodiments, the fixing seat 110 is integrally formed; the fixing seat 110, the first connecting member 101, the second connecting member 102, the third connecting member 103, and the fifth connecting member 104 are made of PLA matte (matte polylactic acid); the above-mentioned screws are made of 304 stainless steel; the main wing beam 140 and the auxiliary wing beam 150 are made of aluminum alloy 6061; the mass block 180 is made of soft iron. Non-magnetic materials are used near the magnet 130 to reduce interference with electromagnetic energy collection. The mass block 180 is made of soft iron, so that the resonant frequency of the entire structure can be reduced after the mass block 180 is added to the end of the beam structure. The larger the mass of the mass block 180, the greater the reduction in the resonant frequency. Under the conditions of limited end space and limited structural bearing capacity, the use of materials with a relatively high density can enhance the role of the mass block 180. PLAmatte has good tensile strength and ductility, and good mechanical and physical properties. This enables it to withstand various mechanical challenges of the fixing seat 110 during use, such as vibration, bending, etc. At the same time, the material is derived from renewable plant resources and has good biodegradability. It is processed by 3D printing technology, has good processability and high cost performance. The main wing spar 140 and the aileron spar 150 are made of aluminum alloy 6061. Because the aluminum alloy has a low density but good mechanical properties, the main wing spar 140 and the aileron spar 150 have a lighter weight while ensuring sufficient strength. In energy collection, light weight and high strength mean that the cantilever beam can respond to external excitation faster and improve energy conversion efficiency. The main wing spar 140 and the aileron spar 150 can be flexibly designed into various shapes and sizes to meet different energy collection requirements, and have good processability and manufacturability. Finally, aluminum alloy is a non-magnetic material with good electromagnetic compatibility. In energy collection, if the main wing spar 140 and the aileron spar 150 need to coexist with other electromagnetic equipment or systems, the electromagnetic compatibility of aluminum alloy can ensure their normal operation and minimize mutual interference.

[0073] 1. For the above implementation, the energy collection results are verified by using the formula, as follows:

[0074] A simplified model verification is performed for the component structure (i.e., a single composite energy collection component) provided with the above-mentioned fixing seat 110, coil 120, magnet 130, main wing beam 140, auxiliary wing beam 150, piezoelectric sheet 160, connecting member 170, and mass block 180:

[0075] The simplified model diagram of the vibration of the main wing spar 140 can be found in Figure 5 .

[0076] In this model: m1 is the main wing, m2 is the aileron, y0, y1, y2 are the vibration displacements of the base, main wing, and aileron respectively, kn (n=1, 2...) is the simplified spring stiffness, (n=1, 2...) is the simplified damping coefficient, and R is the resistance of the piezoelectric part.

[0077] First, for the vibration in the direction perpendicular to the main wing beam 140 surface: the control equation can be written as

[0078]

[0079] Where C p is the clamping capacitance of the piezoelectric element, θ is the electromechanical coupling coefficient, V is the voltage output through R, let q = y2-y1, p = y1-y0, then:

[0080]

[0081] From this, we can get the complex expression of voltage and power, and solve the final solution:

[0082]

[0083] The voltage and power curves are obtained using the Runge-Kutta method, such as Figure 6 shown.

[0084] From the results, we can see that in the lower frequency range of 15-40Hz, there is only one characteristic frequency of 21.0979Hz, the maximum voltage is 27.9987V, and the maximum power is 6.533mW.

[0085] Secondly, for vibration in the direction perpendicular to the aileron beam 150, the aileron beam 150 is the main factor influencing the vibration. Therefore, it is more appropriate to simplify the mass spring damping system to only one mass block. Please refer to the model diagram. Figure 7 .

[0086] The voltage and power curves are also obtained using the Runge-Kutta method, such as Figure 8 shown.

[0087] From the results, it can be seen that when only the secondary spar 150 plays a major role, the characteristic frequency is 21.1979 Hz, which has not changed much, but the maximum voltage is 2.8018 V and the maximum power is 0.0654 mW. Compared with the previous vibration perpendicular to the main spar 140, the collected energy is reduced, but it still meets the multi-directional collection capability.

[0088] When deriving the formula for electromagnetic energy conversion, the coupling of Faraday's law of electromagnetic induction and the kinematic equation is mainly used. Since all the induction coils 120 are on the fixed base 110, the input signal that makes the fixed base 110 vibrate is a sinusoidal function excitation, then:

[0089] y(t)=Ysin(ωt) (5)

[0090] Then the relative velocity of the magnet 130 in the inertial system is:

[0091]

[0092] Where Y is the vibration amplitude of the base, ω is the actual excitation frequency, ω n is the natural frequency, ξ is the mechanical damping ratio, Is the phase angle.

[0093] Next, Faraday's law of electromagnetic induction is used to describe how a changing magnetic field induces an electromotive force in a conductor. The basic formula for the induced electromotive force is:

[0094]

[0095] Where ε is the induced electromotive force; N is the number of turns of the coil 120; φ is the magnetic flux (unit: Weber, Wb) passing through the coil 120; t is time. The magnetic flux φ is related to the displacement z(t) of the coil 120 in the magnetic field and can be expressed as:

[0096] φ=B·A·coS(θ) (8)

[0097] Where B is the magnetic field strength (unit: Tesla, T); A is the cross-sectional area of ​​the coil 120 (unit: square meters, m 2 );θ is the angle between the coil 120 and the magnetic field direction.

[0098] In this design, the magnet 130 and the coil 120 are in an ideal position, θ can be simplified to 0, CoS(θ) can be simplified to 1, and the relationship between magnetic flux and displacement is substituted into Faraday's law of electromagnetic induction, and we can obtain the relationship between induced electromotive force and displacement:

[0099]

[0100] According to the above derivation, the speed at which the coil 120 cuts the magnetic flux lines is The formula for induced electromotive force is:

[0101]

[0102] The instantaneous output power is:

[0103]

[0104] Where R L is the circuit equivalent load, R C The coil is loaded with 120, that is:

[0105]

[0106] This formula also shows that the output power is proportional to the square of the induced electromotive force and inversely proportional to the circuit resistance. By solving the solution, we can get the image of the analytical solution, such as Fig. 9 As shown, the x-axis is time, the y-axis is frequency, and the z-axis is vibration displacement. It can be seen that the peak value of the resonance frequency displacement is around 21 Hz, which is roughly the same as the analytical result of the piezoelectric piece 160 mentioned above.

[0107] 2. For the above implementation, the energy collection results are verified by finite element simulation, as follows:

[0108] The resonant frequency, vibration mode, stress, electric potential and generated electric energy of the piezoelectric piece 160 are studied by finite element analysis method, which is verified by comparison with the formula derivation part. The single composite energy harvesting component is simulated. The simulation analysis mainly focuses on the stress distribution in the main spar 140 and the auxiliary spar 150, and the voltage and power response at different frequencies.

[0109] For piezoelectric sheet 160:

[0110] Simulation steps: A sinusoidal excitation signal, set its sweep frequency, gradually changes at a rate of 0.1 Hz / s, wherein the fixed base 110 is fixed, and the excitation of the fixed base 110 is set to 1g. The displacement potential diagram (such as Fig.10 As shown) and the voltage power coordinate diagram (as shown Fig.11 shown).

[0111] From the simulation results of voltage and power, the characteristic frequency is 27.000Hz, the maximum voltage is 14.772V, and the maximum power is 1.091mW, which are the same as the analytical solution trend.

[0112] Regarding the coil 120 and the magnet 130:

[0113] The simulation of this part focuses on the voltage and current generated by the coil 120, as well as the magnetic field effect during vibration. In order to more clearly show the power generation process of the coil 120 and the magnet 10, a two-dimensional rotating body model is built for the coil 120 and the magnet 10 for specific display, such as Fig.12 , 13 shown.

[0114] Set the vibration frequency to the resonant frequency, simulate with time as the x-axis, and obtain the voltage and current images for the resistor R (such as Fig.14as shown) and the voltage phase diagram (as shown Fig.15 shown).

[0115] Since the magnet 130 vibrates with the vibration of the fixing base 110, and is not a constant magnetic field, the induced electricity generated is alternating current, and a full-bridge rectifier circuit can be set up for AC-DC conversion and energy storage. The images of voltage and current are the voltage and current collected by the resistors in the full-bridge circuit, which conforms to the law of electromagnetic energy collection.

[0116] It can be seen that the flapping-wing bionic vibration energy collector of this embodiment achieves high-efficiency energy collection through bionic design, improves energy utilization through piezoelectric and electromagnetic composite energy collection, and is applicable to various environmental conditions.

[0117] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art can make their own changes and modifications without departing from the spirit and scope of the present application, so the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A bionic flapping-wing composite energy harvester, characterized in that: include: A fixing seat, configured to be fixed at an energy collection location, and having a cavity therein; A coil is fixed to the surface of the fixing seat and is arranged around the cavity; a magnet, located in the cavity, and having a size on the axis of the coil smaller than a size of the cavity on the axis; A main wing beam is plate-shaped, and one end of the main wing beam is fixed to the fixing seat, wherein the extension direction of the main wing beam is perpendicular to the plate surface of the main wing beam; an aileron spar in a plate shape, one end of which is fixed to an end of the main wing spar away from the fixing seat and extends in the same extension direction as the main wing spar, wherein the extension direction of the aileron spar is perpendicular to the plate surface of the aileron spar, and the plate surface of the aileron spar is arranged at an angle greater than 0° and less than or equal to 90° to the plate surface of the main wing spar; and The piezoelectric sheet is attached to and fixed on the plate surface of the main wing beam.

2. The bionic flapping-wing composite energy harvester according to claim 1, characterized in that: The fixing seat comprises: a fixing shaft, a connecting piece and a fixing piece; One end of the fixed shaft is configured to be fixed to the energy collection location, and the other end is fixed to the main wing beam, wherein a first cavity is provided inside the fixed shaft; The connecting member is fixed to the side outer wall surface of the fixed shaft and extends in a direction away from the fixed shaft; The fixing member is fixed to an end of the connecting member away from the fixing shaft, wherein a second cavity is provided inside the fixing member; The number of the coils is two, one coil is fixed to the outer circumference of the fixed shaft and is arranged around the first cavity, and the other coil is fixed to the outer surface of the fixed member and is arranged around the second cavity, wherein the axes of the two coils are parallel to each other; The number of the magnets is two, one of the magnets is located in the first cavity, and the other of the magnets is located in the second cavity.

3. The bionic flapping-wing composite energy collector according to claim 2 is characterized in that: The magnetic force of the magnet located in the cavity of the fixed shaft is greater than the magnetic force of the magnet located in the cavity of the fixing member; and / or, the fixing member is located directly below the main wing beam; and / or, the connecting member includes connecting ends and a connecting body that are sequentially arranged and connected along its extension direction, wherein the cross-sectional area of ​​the connecting end in the extension direction of the connecting member first gradually decreases and then gradually increases, and the cross-sectional area of ​​the connecting body in the extension direction gradually decreases.

4. The bionic flapping-wing composite energy harvester according to claim 1, characterized in that: The fixing seat, the coil, the magnet, the main wing beam, the secondary wing beam and the piezoelectric sheet form the composite energy collection assembly; The number of the composite energy collection components is two; The two composite energy collection components are symmetrically distributed, wherein the axes of the coils of the two composite energy collection components are parallel to each other, and the extension directions of the main wing beams of the two composite energy collection components are opposite.

5. The bionic flapping-wing composite energy collector according to claim 4 is characterized in that: Also includes: The connecting member has two ends respectively connected to one end of the fixing seat of each of the two composite energy collection components connected to the corresponding main wing beam.

6. The bionic flapping-wing composite energy harvester according to claim 5, characterized in that: The connecting member is in a "U" shape. Among them, a groove or a through hole is provided at the top of the "U" shape of the connecting member.

7. The bionic flapping wing type composite energy harvester according to claim 1, wherein the plate width of the main wing beam gradually increases in its extending direction; and / or the plate width of the auxiliary wing beam gradually increases in its extending direction.

8. The bionic flapping-wing composite energy harvester according to claim 1 or 4, characterized in that: It further includes: a mass block provided at one end of the auxiliary wing beam away from the main wing beam.

9. The bionic flapping wing type composite energy harvester according to claim 1, wherein the cavity is formed by a groove provided on the fixed seat. Among them, a first buffer cotton is attached to the peripheral wall surface and the bottom wall surface of the groove, and a second buffer cotton covers the notch of the groove.

10. The bionic flapping wing type composite energy harvester according to claim 1, wherein the number of piezoelectric sheets is two, and the two piezoelectric sheets are respectively attached to and fixed on the two plate surfaces of the main wing beam; and / or the thickness of the part of the piezoelectric sheet close to the fixed seat is greater than the thickness of the part of the piezoelectric sheet away from the fixed seat, and / or the piezoelectric sheet is arranged adjacent to the fixed seat; and / or the auxiliary wing beam extends in a direction away from the fixed seat.

Images