Bionic locust leg type piezoelectric energy collector

Abstract

The embodiment of the invention relates to the technical field of energy collection, in particular to a bionic locust leg type piezoelectric energy collector, which comprises a fixed part, a fixed part and a fixed part, the main beam is in a straight plate shape, one end of the main beam is fixed to the fixing piece, the main beam extends in the direction away from the fixing piece, and the extending direction of the main beam is perpendicular to the plate face of the main beam; the connecting piece is fixed at the other end of the main beam; the auxiliary beam is in a bent plate shape or a similar bent plate shape and is located on the side, away from the main beam, of the connecting piece, one end of the auxiliary beam is fixed to the connecting piece and extends in a bent shape or a similar bent shape in the direction away from the main beam, and the directions of the two plate faces of the auxiliary beam are the same as the directions of the two plate faces of the main beam respectively; and the piezoelectric plate is attached and fixed with the plate surface of the main beam. According to the bionic locust leg type piezoelectric energy collector provided by the embodiment of the invention, the energy collection efficiency can be 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 locust leg-type piezoelectric energy harvester. Background Art

[0002] A piezoelectric energy harvester is a device that converts mechanical energy into electrical energy using the piezoelectric effect. It does not rely on fossil fuels and does not produce greenhouse gas emissions, making it a clean energy solution. Therefore, research on piezoelectric energy harvesters can help promote sustainable energy development and reduce dependence on traditional energy.

[0003] Specifically, the structure of a piezoelectric energy harvester is usually a cantilever beam with a piezoelectric patch. The materials of the piezoelectric patch usually include certain ceramics, polymers and single crystals; when the piezoelectric patch is subjected to mechanical stress, their molecular structure will change, resulting in the separation of positive and negative charges, thereby generating voltage on the two opposite surfaces of the piezoelectric patch; based on this, when vibrations caused by wind, water flow, machine movement, human body movement, etc. appear in the environment and are transmitted to the cantilever beam, the piezoelectric patch set on the cantilever beam is subjected to these stresses, and the electric dipole moment inside the piezoelectric patch will change, resulting in a voltage difference between the two surfaces of the piezoelectric patch. At this time, the charge generated by the piezoelectric patch is collected and output by the charge collection device through the electrodes of the piezoelectric patch.

[0004] However, the vibration energy that can be collected by the piezoelectric energy harvester using the above structure (ie, a cantilever beam provided with a piezoelectric sheet) is relatively single, resulting in low energy collection efficiency. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a bionic locust leg-like piezoelectric energy collector that can improve energy collection efficiency.

[0006] To achieve the above-mentioned effect, an embodiment of the present application provides a bionic locust-leg piezoelectric energy collector, including: a fixing part, configured to be fixed at an energy collection location; a main beam, which is in the shape of a straight plate, and one end of which is fixed to the fixing part and extends in a direction away from the fixing part, wherein the extension direction of the main beam is perpendicular to the plate surface of the main beam; a connecting part, fixed to the other end of the main beam; a secondary beam, which is in the shape of a bent plate or a quasi-plate bent shape, and is located on the side of the connecting part away from the main beam, and one end of which is fixed to the connecting part, and extends in a bent or quasi-bent shape in a direction away from the main beam, wherein the two plate surfaces of the secondary beam are oriented in the same direction as the two plate surfaces of the main beam; and a piezoelectric sheet, which is attached to and fixed to the plate surface of the main beam.

[0007] A bionic locust-leg piezoelectric energy collector provided in an embodiment of the present application makes the sub-beam easier to bend and deform due to the bent plate or plate-like bent shape of the sub-beam, thereby reducing the resonant frequency of the sub-beam. At the same time, it is also easy to induce vibration under various vibration modes (such as: sine wave, square wave, triangle wave, etc.); in this way, combined with the connection and relative position relationship between the sub-beam, the connecting piece, and the main beam, it can be achieved that after the sub-beam is induced to vibrate under low resonant frequency and various vibration modes, it can be transmitted to the main beam via the connecting piece, and then the main beam is caused to vibrate. At the same time, because the vibration is transmitted to the main beam by the sub-beam and the connecting piece, the vibration energy received by the main beam is more adapted to the vibration mode adapted by the main beam after being filtered by the sub-beam and the connecting piece, thereby increasing the energy of the main beam when it vibrates. At this time, combined with the piezoelectric sheet set on the main beam, the vibration energy of the main beam is collected synchronously, so that the energy collection effect can be better achieved. In this way, the bionic locust leg-type piezoelectric energy harvester provided in the embodiment of the present application can not only collect wide vibration frequencies and multiple vibration modes, but also optimize the collection and conversion of vibration energy, thereby improving the collection efficiency of vibration energy.

[0008] In some embodiments, the bionic locust leg-type piezoelectric energy harvester further includes: a first mass block fixed to an end of the sub-beam away from the connecting member. In this way, the resonant frequency of the sub-beam can be further reduced, thereby further increasing the bandwidth of the vibration frequency collected by the bionic locust leg-type piezoelectric energy harvester.

[0009] In some embodiments, at least part of the first mass block is made of magnetic material or magnetizable material; the bionic locust leg piezoelectric energy collector also includes: a fixed frame, located on the side of the first mass block away from the connecting member, and its extension direction is perpendicular to the plate surface of the main beam; and a magnet, arranged adjacent to the first mass block and fixed on the fixed frame; wherein, there is a gap between the fixed frame and the magnet and the first mass block. When at least part of the first mass block is made of magnetizable material, the part of the first mass block made of magnetizable material can be magnetized by the magnet and thus become magnetic. In this way, whether at least part of the first mass block is made of magnetic material or magnetizable material, when the first mass block moves (equivalent to the vibration of the sub-beam), the magnetic field generated by the magnet affects the first mass block, thereby increasing the vibration energy of the sub-beam, and then indirectly increasing the vibration energy of the main beam, thereby improving the energy collection effect of the bionic locust leg piezoelectric energy collector.

[0010] In some embodiments, the number of the magnets is two; there is a spacing between the two magnets, and the two magnets are arranged in sequence along the extension direction of the fixing frame; the plane perpendicular to the extension direction of the fixing frame and located at the midpoint of the positions of the two magnets is a preset plane, wherein the geometric center of the first mass block is located on the preset plane. In this way, combined with the fact that the extension direction of the fixing frame is perpendicular to the plate surface of the main beam, and the two plate surfaces of the auxiliary beam are oriented in the same direction as the two plate surfaces of the main beam, that is, when the auxiliary beam vibrates, the displacement of the first mass block in the extension direction of the fixing frame is relatively large. Therefore, through the above-mentioned design scheme, it can be achieved that the magnet has a greater influence on the first mass block in most cases, thereby better improving the energy collection effect of the bionic locust leg piezoelectric energy collector.

[0011] In some embodiments, the position of the magnet in the extension direction of the fixing frame is configured to be set based on the vibration form of the sub-beam. When the magnet is set in combination with the vibration form of the sub-beam, the influence of the magnet on the sub-beam indirectly through the first mass block can be maximized, thereby further improving the energy collection effect of the bionic locust leg piezoelectric energy harvester.

[0012] In some embodiments, the fixing frame is provided with a plurality of fixing positions along its extension direction; the magnet is selectively fixed at one of the fixing positions. Thus, when the structures such as the secondary beam and the first mass block are damaged by wear and tear, the position of the magnet in the extension direction of the fixing frame can be adjusted, so that the energy collection effect of the bionic locust leg-type piezoelectric energy collector is always in a better state.

[0013] In some embodiments, a plurality of grooves are provided on the lower surface of the first mass block, so that the weight and weight distribution of the first mass block can be changed through the grooves, thereby making it easier to adjust the resonant frequency of the secondary beam.

[0014] In some embodiments, the bionic locust leg piezoelectric energy collector further includes: an auxiliary beam, which is in the shape of a straight plate, and one end of which is fixed to the connecting member and extends in a direction far from the fixing member, wherein the extension direction of the auxiliary beam is perpendicular to the plate surface of the auxiliary beam; wherein the auxiliary beam is configured to have a different resonance frequency from the main beam. In this way, when energy matching the resonance frequency of the auxiliary beam appears, the auxiliary beam resonates and transmits the vibration energy to the main beam via the connecting member, so that the vibration energy of the main beam at this frequency is enhanced, that is, the effect of enhancing the vibration energy that the main beam can generate at the resonance frequency of the auxiliary beam is achieved; in addition, since the auxiliary beam and the main beam are connected to each other via the connecting member, and the main beam and the auxiliary beam are also connected via the connecting member, therefore, when the auxiliary beam transmits energy to the main beam, if a corresponding structure such as the above-mentioned magnet is provided, the vibration energy of the auxiliary beam will also be transmitted to the auxiliary beam and amplified on the auxiliary beam, and then transmitted to the main beam, thereby increasing the vibration energy transmitted from the auxiliary beam to the main beam.

[0015] In some embodiments, the bionic locust leg-type piezoelectric energy harvester further includes: a second mass block fixed to an end of the auxiliary beam away from the connecting member. In this way, the resonance frequency of the auxiliary beam can be further reduced, thereby further increasing the bandwidth of the vibration frequency collected by the bionic locust leg-type piezoelectric energy harvester.

[0016] In some embodiments, the connecting member is plate-shaped; the connecting member has a first plate surface and a second plate surface that are arranged opposite to each other, and a first end and a second end that are arranged opposite to each other in a direction perpendicular to the main beam plate surface; the main beam is fixed to the first end and is located on the first plate surface; the secondary beam is fixed to a position between the first end and the second end of the connecting member and is located on the second plate surface; the auxiliary beam is fixed to the second end and is located on the first plate surface. In this way, when the auxiliary beam transfers energy to the main beam, it will first transfer it to the secondary beam, and preferentially amplify the energy on the secondary beam; in addition, placing the main beam and the auxiliary beam on the same surface of the connecting member, and placing the main beam and the secondary beam on different surfaces of the connecting member, it can be achieved that even if the secondary beam is in a bent plate shape or a plate-like bent shape, it will not force the required spacing between the main beam and the auxiliary beam to be too large, so that the connecting member can be miniaturized, thereby reducing the energy loss on the connecting member, and also enabling the bionic locust leg-type piezoelectric energy collector to be miniaturized.

[0017] In some embodiments, the main beam, the connecting member, and the auxiliary beam are integrally formed; the auxiliary beam is detachably arranged on the connecting member. In this way, on the one hand, the structural strength of the connection between the main beam, the connecting member, and the auxiliary beam can be improved, and on the other hand, the energy loss when the auxiliary beam transfers energy to the main beam can be reduced; and the auxiliary beam is detachably arranged on the connecting member, which can achieve modularization, so that when the energy collector faces different application scenarios, it can choose to adopt an energy collection solution that is more suitable for the scenario.

[0018] 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 beam; and / or the thickness of the portion of the piezoelectric sheet close to the fixing member is greater than the thickness of the portion of the piezoelectric sheet away from the fixing member, and / or the piezoelectric sheet is arranged adjacent to the fixing member. In this way, when the vibration energy of the main beam remains unchanged, the power output of the bionic locust leg piezoelectric energy collector can be increased.

[0019] 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

[0020] 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.

[0021] Figure 1 A schematic diagram of the structure of a single peak energy harvester provided in some embodiments of the present application;

[0022] Figure 2 Another structural schematic diagram of a single peak energy harvester provided in some embodiments of the present application;

[0023] Figure 3 Another structural schematic diagram of a single peak energy harvester provided in some embodiments of the present application;

[0024] Figure 4 A schematic structural diagram of an energy collector having a single peak value and provided with a corresponding magnet provided in some embodiments of the present application;

[0025] Figure 5 Another structural schematic diagram of an energy collector with a single peak value and a corresponding magnet provided in some embodiments of the present application;

[0026] Figure 6 A schematic diagram of the structure of a dual-peak energy harvester provided in some embodiments of the present application;

[0027] Figure 7 Another structural schematic diagram of a dual-peak energy harvester provided in some embodiments of the present application;

[0028] Figure 8 A schematic structural diagram of an energy collector having double peaks and provided with corresponding magnets provided in some embodiments of the present application;

[0029] Fig. 9 Another structural schematic diagram of an energy collector with double peaks and corresponding magnets provided in some embodiments of the present application;

[0030] Fig.10 , 12 , 14, 15 are simplified diagrams of models for energy harvesters provided in some embodiments of the present application;

[0031] Fig.11 , 13 , 16, and 17 are diagrams showing changes in voltage and power with frequency obtained by calculating a simplified energy harvester model provided in some embodiments of the present application;

[0032] Figure 18-21A diagram showing the variation of voltage and power with frequency based on finite element simulation for an energy harvester provided in some embodiments of the present application;

[0033] Figure 22-Figure 25 A diagram showing the variation of vibration displacement and voltage with frequency based on experimental verification output of an energy harvester provided in some embodiments of the present application, wherein the unit of vibration displacement is millimeter (mm).

[0034] The reference numerals in the specific implementation manner are as follows:

[0035] The fixing member 110, the main beam 120, the connecting member 130, the first plate surface 131, the second plate surface 132, the first end 133, the second end 134, the sub-beam 140, the piezoelectric sheet 150, the first mass block 160, the groove 161, the fixing frame 170, the fixing position 171, the magnet 180, the auxiliary beam 190, and the second mass block 200. DETAILED DESCRIPTION

[0036] At present, the structure of a piezoelectric energy harvester is usually a cantilever beam with a piezoelectric sheet. The inventors have noticed that the energy frequency bandwidth that can be harvested by this bionic locust leg-type piezoelectric energy harvester is relatively narrow, and the vibration mode that can be harvested is single.

[0037] In order to improve the energy collection efficiency of the bionic locust leg piezoelectric energy harvester, the applicant has found that the sub-beam is easier to bend and deform due to the bent plate or plate-like bent shape of the sub-beam, thereby reducing the resonant frequency of the sub-beam. At the same time, it is also easy to induce vibration under various vibration modes (such as: sine wave, square wave, triangle wave, etc.); and then innovatively set the connection and relative position relationship between the sub-beam, the connecting member, and the main beam, that is, the main beam in the shape of a straight plate extends in a direction away from the fixing member, wherein the extension direction of the main beam is perpendicular to the plate surface of the main beam; the connecting member is fixed to the other end of the main beam; the sub-beam in the shape of a bent plate or plate-like bent shape is located on the side of the connecting member away from the main beam, One end of the connecting piece is fixed, and extends in a curved or quasi-curved shape in a direction away from the main beam, wherein the two plate surfaces of the auxiliary beam are oriented in the same direction as the two plate surfaces of the main beam; this means that after the auxiliary beam is induced to vibrate at a low resonant frequency and in multiple vibration modes, the vibration is transmitted to the main beam via the connecting piece, thereby causing the main beam to vibrate. At the same time, because the vibration is transmitted to the main beam by the auxiliary beam and the connecting piece, the vibration energy received by the main beam is more adapted to the vibration mode adapted by the main beam after being filtered by the auxiliary beam and the connecting piece, thereby increasing the energy of the main beam during vibration. At this time, the piezoelectric sheet is set on the main beam, and the vibration energy of the main beam is collected synchronously to achieve a better energy collection effect. In this way, the bionic locust leg piezoelectric energy collector provided in the embodiment of the present application can optimize the collection and conversion of vibration energy while being able to collect wide vibration frequencies and multiple vibration modes, thereby increasing the collection efficiency of vibration energy.

[0038] 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.

[0039] See also Figures 1 to 9 In some embodiments, the present application provides a bionic locust leg piezoelectric energy collector, including: a fixing member 110, configured to be fixed at an energy collection location; a main beam 120, which is in the shape of a straight plate, and one end of which is fixed to the fixing member 110 and extends in a direction away from the fixing member 110, wherein the extension direction of the main beam 120 is perpendicular to the plate surface of the main beam 120; a connecting member 130, fixed to the other end of the main beam 120; a sub-beam 140, which is in the shape of a bent plate or a quasi-plate bent shape, is located on the side of the connecting member 130 away from the main beam 120, and one end of which is fixed to the connecting member 130, and extends in a bent or quasi-bent shape in a direction away from the main beam 120, wherein the two plate surfaces of the sub-beam 140 are oriented in the same direction as the two plate surfaces of the main beam 120; and a piezoelectric sheet 150, which is attached to and fixed to the plate surface of the main beam 120.

[0040] The energy collection point refers to the position where energy collection is required; for example, when the vibration energy on the bridge needs to be collected, the energy collection point refers to the position on the bridge, and at this time, the fixing part 110 is fixed on the bridge; and when the vibration energy on the robot needs to be collected, the energy collection point refers to the position on the robot, and at this time, the fixing part 110 is fixed to the legs, torso, etc. of the robot.

[0041] The sub-beam 140 is in a bent plate shape or a plate-like bent shape, which means that at least most of the plate surface of the sub-beam 140 is a curved surface or a quasi-curved surface; wherein the curved surface can be an arc surface, a wavy curved surface, etc., that is, the cross-section of the curved surface is an arc line or a wavy line segment; the quasi-curved surface is a shape similar to a curved surface, and the cross-section of the quasi-curved surface can be a line segment similar to an arc line or a wavy line formed by multiple broken lines, etc.

[0042] The fixing part 110 is used to simulate the hip joint of the locust leg, the main beam 120 is used to simulate the tibia of the locust leg, the connecting part 130 is used to simulate the knee joint of the locust leg, and the auxiliary beam 140 is used to simulate the femur of the locust leg. Based on the biological characteristics of the locust leg, it can work stably under variable environmental conditions and achieve efficient vibration energy conversion. In simple terms, the femur and tarsus of the locust leg are simplified to the auxiliary beam 140 as the main force-bearing structure, and the tibia is simplified to the main beam 120 fixed with the fixing part 110.

[0043] Specifically, since the sub-beam 140 is in a bent plate shape or a plate-like bent shape, the two plate surfaces of the sub-beam 140 are oriented in the same direction as the two plate surfaces of the main beam 120, which means that the two plate surfaces of the sub-beam 140 are roughly oriented in the same direction as the two plate surfaces of the main beam 120; for example, one plate surface of the main beam 120 faces upward and the other plate surface faces downward, and one plate surface of the sub-beam 140 faces roughly upward and the other plate surface faces roughly downward, wherein the direction of the plate surface refers to the direction that the plate surface faces.

[0044] Based on the bionic locust leg piezoelectric energy collector provided in this embodiment, the sub-beam 140 is in a bent plate shape or a plate-like bent shape, so that the sub-beam 140 is easier to bend and deform, thereby reducing the resonant frequency of the sub-beam 140. At the same time, it is also easy to be induced to vibrate under various vibration modes (such as: sine wave, square wave, triangle wave, etc.); in this way, combined with the connection and relative position relationship between the above-mentioned sub-beam 140, the connecting member 130, and the main beam 120, it can be achieved that the sub-beam 140 is induced to vibrate under low resonant frequency and various vibration modes. , transmitted to the main beam 120 via the connector 130, and then causing the main beam 120 to vibrate. At the same time, because the vibration is transmitted to the main beam 120 by the sub-beam 140 and the connector 130, the vibration energy received by the main beam 120 is filtered by the sub-beam 140 and the connector 130 to be more adapted to the vibration mode adapted by the main beam 120, thereby increasing the energy of the main beam 120 during vibration. At this time, the piezoelectric sheet 150 is set on the main beam 120, and the vibration energy of the main beam 120 is collected synchronously, so that the energy collection effect can be better achieved. In this way, the bionic locust leg piezoelectric energy collector can optimize the collection and conversion of vibration energy while being able to collect wide vibration frequencies and multiple vibration modes, thereby increasing the collection efficiency of vibration energy.

[0045] The above-mentioned wide vibration frequency refers to a series of vibration energies from low frequency to high frequency. In actual environments, the frequencies of vibration sources are diverse, for example: they may include low-frequency traffic vibrations, medium-frequency industrial equipment vibrations, and high-frequency vibrations of small electronic devices. Therefore, an ideal energy harvester should be able to cover as wide a frequency range as possible so that energy can be collected from various vibration sources. Multi-vibration modes are vibration energies that exist in the environment that not only have diverse frequencies, but may also contain multiple types of vibration modes. These different vibration modes may exist at the same time and overlap with each other to form a complex vibration environment. The energy harvester of the present application is easy to respond to these different vibration components to maximize the efficiency of energy collection.

[0046] See also Figures 1 to 9In some embodiments, the bionic locust leg piezoelectric energy harvester further includes: a first mass block 160, fixed to an end of the subbeam 140 away from the connector 130. In this way, the resonant frequency of the subbeam 140 can be further reduced, and the bandwidth of the bionic locust leg piezoelectric energy harvester for collecting vibration frequencies can be further increased. In addition, the resonant frequency is reduced, that is, a small input change may lead to a large output change, and this characteristic is particularly obvious in low-frequency vibrations.

[0047] See also Figure 4 , 5 , 8, 9. In some embodiments, at least a portion of the first mass block 160 is made of magnetic material or magnetizable material; the bionic locust leg piezoelectric energy collector also includes: a fixing frame 170, which is located on the side of the first mass block 160 away from the connecting member 130, and its extension direction is perpendicular to the plate surface of the main beam 120; and a magnet 180, which is arranged adjacent to the first mass block 160 and fixed on the fixing frame 170; wherein, both the fixing frame 170 and the magnet 180 are spaced apart from the first mass block 160.

[0048] When at least part of the first mass block 160 is made of a magnetizable material, the part of the first mass block 160 made of the magnetizable material can be magnetized by the magnet 180 and thus has magnetism. When the first mass block 160 is made of a magnetic material, the part of the first mass block 160 made of the magnetic material itself has magnetism.

[0049] The fixing frame 170 is located on the side of the first mass block 160 away from the connecting member 130, and there is a gap between the fixing frame 170 and the first mass block 160, that is, the fixing frame 170 is not connected to the fixing member 110, the main beam 120, the connecting member 130, the auxiliary beam 140, the piezoelectric sheet 150, and the first mass block 160. In this way, when the main beam 120 and the auxiliary beam 140 vibrate, it can be ensured that the fixing frame 170 does not affect the vibration of the main beam 120 and the auxiliary beam 140. In addition, since there is a gap between the magnet 180 and the first mass block 160, the magnet 180 only generates a magnetic force on the first mass block 160, and does not generate a force based on physical direct or indirect contact.

[0050] In this way, whether at least a portion of the first mass block 160 is made of magnetic material or magnetizable material, when the first mass block 160 moves (equivalent to the vibration of the sub-beam 140), the magnetic field generated by the magnet 180 affects the first mass block 160, thereby increasing the vibration energy of the sub-beam 140, and then indirectly improving the vibration energy of the main beam 120, thereby improving the energy collection effect of the bionic locust leg piezoelectric energy collector.

[0051] See also Figure 4 , 5, 8, 9, in some embodiments, the number of the magnets 180 is two; there is a distance between the two magnets 180, and the two magnets 180 are arranged in sequence along the extension direction of the fixing frame 170.

[0052] In this embodiment, a plane perpendicular to the extension direction of the fixing frame 170 and located at the midpoint of the positions of the two magnets 180 is a preset plane, wherein the geometric center of the first mass block 160 is located on the preset plane. In simple terms, the orthographic projection of the geometric center of the first mass block 160 on the fixing frame 170 is located at the midpoint of the two magnets 180.

[0053] Based on the fact that the extension direction of the fixing frame 170 is perpendicular to the plate surface of the main beam 120, and the two plate surfaces of the sub-beam 140 are oriented in the same direction as the two plate surfaces of the main beam 120, that is, when the sub-beam 140 vibrates, the first mass block 160 reciprocates similar to the path of a pendulum. Specifically, the displacement of the first mass block 160 in the extension direction of the fixing frame 170 is large, while the displacement of the first mass block 160 in the directions opposite to each other at the two ends of the sub-beam 140 is small, wherein the directions opposite to each other at the two ends of the sub-beam 140 refer to the direction from one end of the sub-beam 140 to the other end.

[0054] Therefore, through the design of the present embodiment, combined with the large displacement of the first mass block 160 in the extension direction of the fixing frame 170, it can be achieved that the magnet 180 has a greater influence on the first mass block 160 in most cases; specifically, see Figure 5 , 9 That is, when the first mass block 160 swings upward, the upper one of the two magnets 180 generates a larger magnetic force on the first mass block 160; and when the first mass block 160 swings downward, the lower one of the two magnets 180 generates a larger magnetic force on the first mass block 160, thereby better improving the energy collection effect of the bionic locust leg type piezoelectric energy collector. In addition, since the effect of the magnetic field generated by the magnet 180 on the first mass block 160 is not limited to the magnetic force in the extension direction of the fixing frame 170, but also has magnetic force in the opposite directions of the two ends of the sub-beam 140, the two magnets 180 can also generate magnetic force on the first mass block 160 in the opposite directions of the two ends of the sub-beam 140, thereby further increasing the energy of the sub-beam 140 when it vibrates, thereby further improving the energy collection effect of the bionic locust leg type piezoelectric energy collector.

[0055] It should be noted that the midpoint setting in this embodiment can adapt to the vibration form of the sub-beam 140 in most cases, thereby improving the energy collection effect of the bionic locust leg-type piezoelectric energy collector in most cases.

[0056] See also Figure 4 , 58, 9. In some embodiments, the position of the magnet 180 in the extension direction of the fixing frame 170 is configured to be set based on the vibration mode of the sub-beam 140.

[0057] The vibration form of the sub-beam 140 refers to the shape of the sub-beam 140 at various locations during the vibration process. Since the sub-beam 140 is in the shape of a curved plate or a quasi-curved plate, the vibration form of the sub-beam 140 is more complex and changeable than that of the main beam 120 which is in the shape of a straight plate. For example, when the bending degree and bending direction of the sub-beam 140 are different, the vibration form of the sub-beam 140 will change. Simply put, when the sub-beam 140 vibrates, combined with Figure 5 , 9 , affected by factors such as the bending degree and bending direction of the sub-beam 140, the displacement of the first mass block 160 upward is different from the displacement of the first mass block 160 downward. At this time, when the position of the magnet 180 is set in combination with the vibration form of the sub-beam 140, the influence of the magnet 180 on the sub-beam 140 indirectly through the first mass block 160 can be maximized, thereby further improving the energy collection effect of the bionic locust leg piezoelectric energy harvester.

[0058] See also Figure 4 , 5 , 8, 9, in some embodiments, the fixing frame 170 is provided with a plurality of fixing positions 171 along its extension direction; the magnet 180 is selectively fixed on a fixing position 171 .

[0059] It should be noted that the present application does not limit the shape and installation method of the fixing position 171. For example, in the present embodiment, the fixing position 171 is a hole opened on the fixing frame 170. At this time, a screw or other part can be passed through the magnet 180 and screwed into a fixing position 171 of the fixing frame 170, so that the magnet 180 is fixed to a fixing position 171.

[0060] In this way, when structures such as the sub-beam 140 and the first mass block 160 are damaged by wear and tear, the position of the magnet 180 in the extension direction of the fixed frame 170 can be adjusted to achieve the maximum effect of the magnet 180 on the sub-beam 140 and the first mass block 160, thereby ensuring that the energy collection effect of the bionic locust leg-type piezoelectric energy collector is always in an optimal state.

[0061] See also Figure 3 In some embodiments, a plurality of grooves 161 are provided on the lower surface of the first mass block 160. In this embodiment, two long strip grooves, two triangular grooves and one regular polygonal groove are provided on the lower surface of the first mass block 160, and the aforementioned grooves are symmetrically distributed. In this way, the weight and weight distribution of the first mass block 160 can be changed through the grooves 161, so that the resonant frequency of the sub-beam 140 can be adjusted more easily.

[0062] See also Figures 6 to 9 In some embodiments, the bionic locust leg piezoelectric energy collector also includes: an auxiliary beam 190, which is in the shape of a straight plate, and one end of which is fixed to the connecting member 130, and extends in a direction away from the fixing member 110, wherein the extension direction of the auxiliary beam 190 is perpendicular to the plate surface of the auxiliary beam 190; wherein the auxiliary beam 190 is configured to have a different resonance frequency from the main beam 120.

[0063] In this way, when energy matching the resonant frequency of the auxiliary beam 190 appears, the auxiliary beam 190 resonates and transfers the vibration energy to the main beam 120 via the connecting member 130, so that the vibration energy of the main beam 120 at this frequency is enhanced, that is, the effect of enhancing the vibration energy that the main beam 120 can generate at the resonant frequency of the auxiliary beam 190 is achieved.

[0064] In addition, since the auxiliary beam 190 and the main beam 120 are connected to each other via the connecting piece 130, and the main beam 120 and the sub-beam 140 are also connected via the connecting piece 130, when the auxiliary beam 190 transfers energy to the main beam 120, combined with the above-mentioned implementation method of corresponding structures such as the magnet 180, the vibration energy of the auxiliary beam 190 will also be transmitted to the sub-beam 140 and amplified on the sub-beam 140, and then transferred to the main beam 120, thereby increasing the vibration energy transferred from the auxiliary beam 190 to the main beam 120.

[0065] See also Figures 6 to 9 In some embodiments, the bionic locust leg type piezoelectric energy harvester further includes: a second mass block 200, fixed to an end of the auxiliary beam 190 away from the connecting member 130. In this way, the resonance frequency of the auxiliary beam 190 can be further reduced, and then the bandwidth of the bionic locust leg type piezoelectric energy harvester collecting vibration frequencies can be further increased.

[0066] See also Figures 6 to 9 In some embodiments, the connecting member 130 is plate-shaped; the connecting member 130 has a first plate surface 131 and a second plate surface 132 that are oppositely arranged, and has a first end 133 and a second end 134 that are oppositely arranged in a direction perpendicular to the plate surface of the main beam 120; the main beam 120 is fixed to the first end 133 and is located on the first plate surface 131; the secondary beam 140 is fixed to a position between the first end 133 and the second end 134 of the connecting member 130 and is located on the second plate surface 132; the auxiliary beam 190 is fixed to the second end 134 and is located on the first plate surface 131.

[0067] It should be noted that, in order to facilitate understanding of the first end 133 and the second end 134 , a dotted line is used for division in the drawings, that is, the dotted line used to divide the first end 133 and the second end 134 is not the structure of the connector 130 itself.

[0068] In this way, when the auxiliary beam 190 transfers energy to the main beam 120, it will first transfer it to the auxiliary beam 140, and preferentially amplify the energy on the auxiliary beam 140; in addition, the main beam 120 and the auxiliary beam 190 are placed on the same surface of the connecting member 130, and the main beam 120 and the auxiliary beam 140 are placed on different surfaces of the connecting member 130. It can be achieved that even if the auxiliary beam 140 is in a bent plate shape or a plate-like bent shape, it will not force the required spacing between the main beam 120 and the auxiliary beam 190 to be too large, so that the connecting member 130 can be miniaturized, thereby reducing the energy loss in the connecting member 130, and also enabling the bionic locust leg-type piezoelectric energy collector to develop towards miniaturization.

[0069] See also Figures 1 to 9 In some embodiments, the main beam 120, the connecting member 130, and the secondary beam 140 are integrally formed; see Figures 6 to 9 , the auxiliary beam 190 is detachably arranged on the connecting member 130. In this way, on the one hand, the structural strength of the connection between the main beam 120, the connecting member 130, and the auxiliary beam 140 can be improved, and on the other hand, the energy loss when the auxiliary beam 140 transfers energy to the main beam 120 can be reduced; and the auxiliary beam 190 is detachably arranged on the connecting member 130, which can realize modularization, so that when the energy collector faces different application scenarios, it is possible to selectively adopt an energy collection solution that is more suitable for the scenario.

[0070] See also Figures 1 to 9 In some embodiments, the number of the piezoelectric sheets 150 is two, and the two piezoelectric sheets 150 are respectively attached to and fixed on the two plate surfaces of the main beam 120. In this way, when the vibration energy of the main beam 120 remains unchanged, the power output of the bionic locust leg piezoelectric energy collector can be increased.

[0071] In one embodiment, the thickness of the portion of the piezoelectric sheet 150 close to the fixing member 110 is greater than the thickness of the portion of the piezoelectric sheet 150 far from the fixing member 110, and / or the piezoelectric sheet 150 is disposed adjacent to the fixing member 110. Since the deformation of the portion of the main beam 120 close to the fixing member 110 is larger when the main beam 120 vibrates, the power output of the bionic locust leg piezoelectric energy collector can be increased when the vibration energy of the main beam 120 remains unchanged.

[0072] In some embodiments, the main beam 120, the connecting member 130, and the auxiliary beam 140 are made of 6061 aluminum alloy, so that the main beam 120, the connecting member 130, and the auxiliary beam 140 have high strength, light weight, good rigidity and excellent processing performance; the auxiliary beam 140 and the first mass block 160 are fixed with double-sided tape to avoid the use of materials such as screws that may affect the magnet 180; the auxiliary beam 190 and the second mass block 200 can be fixed with screws; the auxiliary beam 190 and the connecting member 130 are fixed with screws; the auxiliary beam 190 is made of 6061 aluminum alloy, so that the auxiliary beam 190 has high strength, light weight, good rigidity and excellent processing performance; the piezoelectric sheet 150 can be made of PZT-5H material; the piezoelectric sheet 150 can be bonded to the main beam 120 with double-sided tape.

[0073] It should be noted that the present application does not limit the circuit for energy collection, and a full-bridge rectifier circuit can be used as the main circuit to convert the alternating current generated by the piezoelectric sheet 150 into direct current for use in various power systems. Specifically, the energy collection module of LTC3588-1 (a nanopower energy collection power supply) can be used, and components such as resistors and capacitors can be selected according to the characteristics of the designed device. According to the data sheet of the LTC3588 module, a circuit diagram can be designed, including the connection method between the piezoelectric sheet 150 and the LTC3588 module, as well as necessary external components such as capacitors and rectifiers. For example, a 47uF capacitor can be connected externally to store energy, and an LED and a current-limiting resistor can be connected at the output end. Next, the LTC3588 module is integrated with the aforementioned energy collector structure, and the connection endpoints are connected using DuPont wires to ensure that the piezoelectric sheet 150 can effectively convert vibration energy into electrical energy.

[0074] For the above-mentioned implementation methods, the model simplification verification is carried out as follows:

[0075] 1. For the single peak value of the above-mentioned fixing member 110, main beam 120, connecting member 130, auxiliary beam 140, piezoelectric sheet 150, and first mass block 160 (its structure is shown in FIG. Figures 1 to 3 As shown) to perform model simplification verification:

[0076] See model diagram Fig.10 .

[0077] The governing equation is as follows:

[0078]

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

[0080]

[0081] This gives us the complex expression of voltage and power, and we can find the final solution:

[0082]

[0083] The voltage and power curves are obtained using the Runge-Kutta method, such as Fig.11 shown.

[0084] From the results, it can be seen that the characteristic frequency in the range of 10-30Hz with a low frequency is 16.092Hz, the maximum voltage is 5.271V, and the maximum power is 0.028mW.

[0085] 2. For the double peak value (its structure diagram is as shown in FIG. 1 ) provided with the fixing member 110, the main beam 120, the connecting member 130, the auxiliary beam 140, the piezoelectric sheet 150, the first mass block 160, the auxiliary beam 190, and the second mass block 200 Figure 6 , 7 As shown) to perform model simplification verification:

[0086] See model diagram Fig.12 .

[0087] The governing equation is as follows:

[0088]

[0089] Let q2 = y2-y1, q3 = y3-y1, p2 = y1-y0, then

[0090]

[0091] The power and voltage at this time are

[0092]

[0093] The voltage and power curves are obtained using the Runge-Kutta method, such as Fig.13 shown.

[0094] From the results, it can be seen that within the range of 10-70Hz, the first characteristic frequency is 16.198Hz and the second characteristic frequency is 42.096Hz. The voltages obtained are 7.47V and 1.419V, respectively, and the power is 0.102mW and 0.002mW, respectively. Compared with the single peak value mentioned above, the energy collection capacity of the double peak value has been improved.

[0095] 3. For the single peak value of the above-mentioned fixing member 110, main beam 120, connecting member 130, auxiliary beam 140, piezoelectric sheet 150, first mass block 160, fixing frame 170, and magnet 180 (its structure diagram is as shown in FIG. Figure 4 , 5 As shown in the figure); and for the double peak value (its structure diagram is as shown in the figure) provided with the above-mentioned fixing member 110, main beam 120, connecting member 130, auxiliary beam 140, piezoelectric sheet 150, first mass block 160, fixing frame 170, magnet 180, auxiliary beam 190, and second mass block 200 Figure 8 , 9 Verify as shown:

[0096] Single peak, see model diagram Fig.14 ; For double peaks, see the model diagram Fig.15 .

[0097] The extending direction of the fixing frame 170 is taken as the Y direction, and the extending direction of the main beam 120 is taken as the X direction.

[0098] Then there is the analysis of the magnetic formula:

[0099]

[0100] Where a is the vacuum magnetic permeability, m a and m b are the magnetic moments of the magnet and soft iron respectively, r is the distance between their centers, and ψ is the angle formed by the soft iron block and the permanent magnet during vibration.

[0101] After the magnetic force is introduced, the theoretical derivation has the following changes:

[0102]

[0103] According to the above formula, the voltage and power formula after the introduction of nonlinear force can be calculated as follows:

[0104]

[0105] The voltage and power curves are also obtained using the Runge-Kutta method, where the single peak value is shown in Fig.16 ; Double peak Fig.17 .

[0106] It can be seen that the characteristic frequency of the single peak value can fluctuate within the range of 11.099Hz, with a maximum amplitude of 12.399Hz, a maximum voltage of 8.994V, and a maximum power of 0.081mW. For the double peak value, the first characteristic frequency is 14.398Hz, and the second characteristic frequency is 39.696Hz. The voltages are 19.983V and 5.947V, respectively, and the electric powers are 0.200mW and 0.018mW, respectively. Therefore, under the action of the introduction of the magnet 180, both structures effectively expand the frequency band of energy collection; that is, expand the range of effective energy collection.

[0107] In addition, verification can also be performed based on finite element simulation, as follows:

[0108] The resonant frequency, vibration mode, stress, electric potential and generated electric energy of the piezoelectric sheet 150 were studied by finite element analysis method, and the verification was compared with the analytical solution. The models without corresponding magnets 180 and with corresponding magnets 180 of single peak and double peak were simulated. The simulation analysis mainly focused on the stress distribution, voltage and power response at different frequencies in the above-mentioned bionic locust leg piezoelectric energy harvester. Simulation steps: a sinusoidal excitation signal, set its sweep frequency, and gradually change at a rate of 0.1Hz / s. The resistance of the external resistor is 106Q.

[0109] (a) Single peak without corresponding magnet 180: In the range of 10-30Hz, there is only one characteristic frequency of 19.500Hz, the maximum voltage is 5.630V, and the maximum power is 0.016mW. Fig.18 .

[0110] (b) Single peak value has corresponding magnet 180: in the range of 10-30Hz, there is only one characteristic frequency of 19.925Hz, the maximum voltage is 12.770V, and the maximum power is 0.374mW. Fig.19 .

[0111] (c) Double peak value without corresponding magnet 180: In the range of 10-70 Hz, there are two characteristic frequencies of 17.500 Hz and 50.100 Hz, peak voltages of 7.042 V and 1.349 V, and peak powers of 0.025 mW and 0.001 mW. Fig. 20 .

[0112] (d) The double peak has a corresponding magnet 180: in the range of 10-70 Hz, there are two characteristic frequencies of 18.100 Hz and 45.000 Hz, peak voltages of 13.214 V and 5.394 V, and peak powers of 0.132 mW and 0.015 mW. Fig.21 .

[0113] It can also be seen from the finite element simulation results that under the action of magnetic force, the energy collection amplitude of the two structures increases, the frequency band is widened, and the frequency range of energy collection increases. In addition, for the double peaks, the distance between the resonant frequencies is reduced, thereby promoting effective energy conversion over a wider spectrum.

[0114] In addition, it can also be verified based on experiments, where the experimental device consists of an optical test bench, a small vibration table, a pulse generator, a power amplifier, a displacement sensor, and an external display device. The pulse generator generates sinusoidal excitation, which is provided by a small vibration table manufactured by Hangzhou Yiheng Technology Co., Ltd.

[0115] Experimental results:

[0116] (a) Single peak without corresponding magnet 180: In the range of 10-30Hz, there is only one characteristic frequency of 14.473Hz, peak displacement of 0.165mm, and peak voltage of 1.973V. Fig. 22 .

[0117] (b) Single peak has corresponding magnet 180: in the range of 10-30Hz, there is only one characteristic frequency of 19.925Hz, peak displacement of 1.112mm, and peak voltage of 2.056V. Fig.23 .

[0118] (c) Double peaks without corresponding magnet 180: In the range of 10-70 Hz, there are two characteristic frequencies of 12.427 Hz and 43.996 Hz, peak displacements of 0.871 mm and 0.194 mm, and peak voltages of 2.438 V and 0.430 V. Fig.24 .

[0119] (d) The double peak has a corresponding magnet 180: in the range of 10-70 Hz, there are two characteristic frequencies of 11.505 Hz and 37.945 Hz, peak displacements of 1.092 mm and 0.160 mm, and peak voltages of 3.104 V and 1.166 V. Fig.25 .

[0120] Combining the simplified analytical solution, finite element simulation solution and experimental results of the above model, the specific comparison results are shown in the following table:

[0121]

[0122]

[0123] This consistency verifies the rationality of the design and proves that the energy harvesting structure adopted is not only good in non-integration, but also effective in integration strategy. The correspondence between the experimental and simulation results further confirms the accuracy and reliability of the design method and demonstrates the potential and effectiveness of the energy harvester in practical applications.

[0124] 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 locust leg-type piezoelectric energy harvester, characterized in that: include: A fixing member configured to be fixed at an energy collection location; The main beam is in the shape of a straight plate, one end of which is fixed to the fixing member and extends in a direction away from the fixing member, wherein the extension direction of the main beam is perpendicular to the plate surface of the main beam; A connecting member, fixed to the other end of the main beam; The auxiliary beam is in a curved plate shape or a plate-like curved shape, is located on a side of the connecting member away from the main beam, and the connecting member is fixed at one end thereof, and extends in a curved or quasi-curved shape in a direction away from the main beam, wherein the two plate surfaces of the auxiliary beam are oriented in the same direction as the two plate surfaces of the main beam; and The piezoelectric sheet is attached to and fixed on the plate surface of the main beam.

2. The bionic locust leg type piezoelectric energy harvester according to claim 1 is characterized in that: Also includes: The first mass block is fixed to an end of the sub-beam away from the connecting member.

3. The bionic locust leg type piezoelectric energy harvester according to claim 2 is characterized in that: At least part of the first mass is made of a magnetic material or a magnetizable material; The bionic locust leg type piezoelectric energy harvester also includes: a fixing frame, located on a side of the first mass block away from the connecting member, and extending in a direction perpendicular to the plate surface of the main beam; and a magnet, disposed adjacent to the first mass block and fixed on the fixing frame; Wherein, a gap is left between the fixing frame and the magnet and the first mass block.

4. The bionic locust leg type piezoelectric energy harvester according to claim 3 is characterized in that: The number of the magnets is two; There is a distance between the two magnets, and the two magnets are arranged in sequence along the extension direction of the fixing frame: A surface perpendicular to the extension direction of the fixing frame and located at the midpoint of the positions of the two magnets is a preset surface, wherein the geometric center of the first mass block is located on the preset surface.

5. The bionic locust leg type piezoelectric energy harvester according to claim 3 is characterized in that: The position of the magnet in the extension direction of the fixing frame is configured to be set based on the vibration form of the sub-beam; and / or, the fixing frame is provided with a plurality of fixing positions along its extension direction, and the magnet is selectively fixed at one of the fixing positions; and / or, a plurality of grooves are provided on the lower surface of the first mass block.

6. The bionic locust leg type piezoelectric energy harvester according to claim 1 is characterized in that: Also includes: The auxiliary beam is in the shape of a straight plate, one end of which is fixed to the connecting member and extends in a direction away from and close to the fixing member, wherein the extension direction of the auxiliary beam is perpendicular to the plate surface of the auxiliary beam; Wherein, the auxiliary beam is configured to have a resonance frequency different from that of the main beam.

7. The bionic locust leg type piezoelectric energy harvester according to claim 6 is characterized in that: Also includes: The second mass block is fixed to an end of the auxiliary beam away from the connecting member.

8. The bionic locust leg type piezoelectric energy harvester according to claim 6, characterized in that: The connecting member is in the shape of a plate; the connecting member has a first plate surface and a second plate surface which are arranged opposite to each other, and a first end portion and a second end portion which are arranged opposite to each other in a direction perpendicular to the main beam plate surface; The main beam is fixed to the first end and is located on the first plate surface; The sub-beam is fixed at a position between the first end and the second end of the connecting member and is located on the second plate surface; The auxiliary beam is fixed to the second end portion and is located on the first plate surface.

9. The bionic locust leg type piezoelectric energy harvester according to claim 8, characterized in that: The main beam, the connecting member, and the auxiliary beam are integrally formed; The auxiliary beam is detachably arranged on the connecting member.

10. The bionic locust leg type piezoelectric energy harvester according to claim 1, characterized in that: Also includes: There are two piezoelectric sheets, and the two piezoelectric sheets are respectively attached to and fixed on two plate surfaces of the main beam; and / or, The thickness of the portion of the piezoelectric sheet close to the fixing member is greater than the thickness of the portion of the piezoelectric sheet far from the fixing member. and / or, The piezoelectric sheet is disposed adjacent to the fixing member.

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