Cantilever piezoelectric vibration energy harvester and design method

Abstract

The application provides a kind of cantilever piezoelectric vibration energy harvester and design method, including piezoelectric vibration energy harvester and nonlinear force customization device;Piezoelectric vibration energy harvester includes cantilever beam;Nonlinear force customization device includes lifting platform, raceway, rolling element, linear motion mechanism, horizontal spring and pre-tightening nut;Linear motion mechanism is set on lifting platform, pre-tightening nut is connected one end of linear motion mechanism by horizontal spring, for adjusting the pre-compression force of horizontal spring;The outer wall surface of rolling element is closely attached to raceway;When raceway is set on the other end of linear motion mechanism, rolling element is set on the free end of cantilever beam;When rolling element is set on the other end of linear motion mechanism, raceway is set on the free end of the cantilever beam.The application realizes the customization demand of nonlinear force in energy harvester by customizing the profile curve of raceway, using the reaction force generated when bearing or roller rolls on raceway.

Description

Technical Field

[0001] This invention relates to vibration energy harvesters, specifically to a customizable nonlinear force cantilever beam piezoelectric vibration energy harvester and its design method. Background Technology

[0002] Currently, sensors are widely used in industrial IoT, environmental health monitoring, and other fields. However, relying on chemical batteries for power will face the challenge of large-scale battery replacement in the future. Therefore, some researchers have proposed capturing vibration energy from the environment and converting it into electrical energy to power the sensors. Various harvesters capable of capturing environmental vibration energy have been proposed, among which the cantilever beam piezoelectric vibration energy harvester is widely used. It consists of a cantilever beam, a piezoelectric plate placed at the base of the beam, and a mass block placed at the top of the beam, making it a typical linear vibration energy harvester. For linear vibration energy harvesters, high energy harvesting efficiency is only achieved near their resonant frequency; the efficiency drops sharply slightly off the natural frequency, resulting in a narrow energy harvesting bandwidth. To improve the performance of vibration energy harvesters, many researchers have proposed introducing nonlinear forces into linear cantilever beam piezoelectric vibration energy harvesters, utilizing the broadband response characteristics of nonlinear vibration to improve their energy harvesting performance.

[0003] In designing nonlinear cantilever piezoelectric vibration energy harvesters, the form of the nonlinear force has a significant impact on its performance; some forms of nonlinear force can even degrade the harvester's performance. Therefore, it is necessary to consider factors such as the vibration characteristics of the cantilever piezoelectric vibration energy harvester itself, the vibration level of the surrounding environment, and the vibration frequency to rationally optimize the form of the nonlinear force. This requires introducing a method for nonlinear force that can precisely control each coefficient in the nonlinear force polynomial function, i.e., achieving customized nonlinear force. However, in many current patents for cantilever-type vibration energy harvesters, although nonlinear forces can be introduced through various methods, the individual coefficients within the nonlinear force cannot be precisely controlled. For example, Chinese patent CN114039508A, titled "Nonlinear Piezoelectric Energy Harvesting Device," uses the magnetic force between two magnets to introduce a nonlinear force, thereby improving the working efficiency and widening the operating bandwidth of the energy harvesting device. However, while adjusting the magnet distance can easily change the form of the nonlinear force, it cannot precisely control each coefficient within the nonlinear force. Chinese Patent No. CN113507234B, titled "A Nonlinear Multidirectional Piezoelectric Energy Recovery Device," also introduces nonlinear force through magnetism to construct a nonlinear bistable system. Using an irregularly shaped cantilever beam structure and magnetic excitation, vibration energy can be harvested in three directions. However, the magnetic nonlinearity can only be simply adjusted and cannot meet customized requirements. Chinese Patent No. CN112713807B, titled "A Bistable Vortex-Induced Vibration Energy Harvesting Device Based on Internal Resonance," utilizes the magnetic repulsion between magnets to generate a nonlinear force, producing bistable vibration. Vortex-induced vibration is generated by fluid impacting a blunt body at the top of the cantilever beam, and the fluid kinetic energy is converted into electrical energy using a piezoelectric element. Similarly, the nonlinear force in this patent cannot be customized. Chinese Patent No. CN114039507A, titled "A Multidirectional Nonlinear Broadband Piezoelectric Energy Harvesting Device Utilizing Spring Jump Effect," utilizes the spring instability jump effect to generate a nonlinear force and achieves multidirectional vibration energy harvesting through coupling with a nonlinear permanent magnet. In this patent, the nonlinear force can be easily adjusted by regulating the spring stiffness, but it cannot be precisely customized. Chinese patent CN110365250B, titled "A Passive Adaptive Tuning Harmonic Vibration Energy Harvesting Device," utilizes the geometric nonlinearity of a cantilever beam to generate a gradually stiffening nonlinear force. The sliding of a free slider on the cantilever beam allows the nonlinear system to operate in a high-energy orbit, improving energy conversion efficiency. Similarly, the nonlinear force generated based on geometric nonlinearity is also difficult to customize for each coefficient. Chinese patent CN109783836A, titled "Nonlinear Model Establishment and Verification Analysis Method for L-shaped Piezoelectric Energy Harvester," also utilizes the geometric nonlinearity of an L-shaped beam to generate a nonlinear force, thus also making it difficult to meet the customization requirements for each coefficient of the nonlinear force.Chinese patent CN207603479U, titled "A Vibration Energy Harvester," utilizes the collision between a mass block at the free end of a cantilever beam and an adjacent blocking block to generate a nonlinear force, thereby widening the vibration frequency band for energy harvesting and improving the harvesting efficiency. While the nonlinear force can be easily adjusted by regulating the collision distance, it falls far short of meeting customized nonlinear force requirements. Chinese patent CN113556057A, titled "A Multi-Cantilever Beam Wideband Piezoelectric Vibration Energy Harvesting Device," generates a nonlinear force through the collision between three cantilever beams; similarly, only simple adjustments to the nonlinear force are possible. Chinese patent CN105610347A, titled "A Nonlinear Wideband Piezoelectric Vibration Energy Harvester," uses both nonlinear magnetic force and spring force to construct a bistable piezoelectric vibration energy harvester. The nonlinear magnetic field repulsion and elastic amplification mechanism effectively amplify weak vibration displacements in the environment, improving the harvester's efficiency. However, this method also struggles to precisely control the nonlinear force.

[0004] In summary, common methods for introducing nonlinear mechanisms include magnetic repulsion or attraction, geometric nonlinearity, inclined springs, or collisions. However, the methods described in the aforementioned patents can only adjust one coefficient in the nonlinear force polynomial function, failing to simultaneously and precisely adjust all coefficients. For example, changing the distance between magnets will simultaneously change all coefficients in the nonlinear force, with varying degrees of change, making it difficult to coordinate all coefficients at the same time, which greatly limits the performance improvement of nonlinear energy harvesters. If all coefficients of the nonlinear force could be precisely adjusted at will when designing a nonlinear cantilever beam piezoelectric vibration energy harvester, the performance of the energy harvester would be greatly improved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a cantilever beam piezoelectric vibration energy harvester with customizable nonlinear force, solving the problem that current energy harvesters cannot accurately adjust the coefficients of nonlinear force, which is of great significance for designing high-performance energy harvesters.

[0006] The cantilever beam piezoelectric vibration energy harvester provided by the present invention includes a piezoelectric vibration energy harvester and a nonlinear force customization device;

[0007] The piezoelectric vibration energy harvester includes a cantilever beam;

[0008] The nonlinear force customization device includes a lifting platform, a roller track, rolling elements, a linear motion mechanism, a horizontal spring, and a preload nut; the linear motion mechanism is mounted on the lifting platform, and the preload nut is connected to one end of the linear motion mechanism through the horizontal spring to adjust the preload of the horizontal spring.

[0009] The outer wall surface of the rolling element is in close contact with the raceway; when the raceway is located at the other end of the linear motion mechanism, the rolling element is located at the free end of the cantilever beam; when the rolling element is located at the other end of the linear motion mechanism, the raceway is located at the free end of the cantilever beam.

[0010] Preferably, it also includes a mass block;

[0011] The rolling element is connected to the free end via the mass block, which is used to adjust the first natural frequency of the cantilever beam.

[0012] Preferably, the linear motion mechanism adopts a linear guide slider mechanism, which includes a linear guide and a slider mechanism;

[0013] The slider mechanism is disposed on the upper surface of the lifting platform; the linear guide rail is disposed in the slider mechanism and can slide along the slider mechanism.

[0014] Preferably, the rolling element is a bearing;

[0015] The cantilever beam is connected to the inner ring of the bearing via the mass block; the outer ring of the bearing is tightly fitted to the raceway.

[0016] Preferably, the piezoelectric vibration energy harvester further includes a column, a piezoelectric sheet, and an energy storage circuit;

[0017] The cantilever beam is mounted on the column; a piezoelectric element is mounted on the cantilever beam, and the output end of the piezoelectric element is electrically connected to the energy storage circuit.

[0018] Preferably, the piezoelectric element is disposed on the upper side, lower side, or both sides of the cantilever beam. Preferably, the column is a platform capable of being raised and lowered.

[0019] Preferably, the profile curve of the raceway for:

[0020] in, yes Upper coordinate point, yes Upper coordinate point, yes Taking the derivative with respect to x, For its nonlinear force, For the horizontal spring stiffness, This is the pre-compression amount. This refers to the bending stiffness of the cantilever beam.

[0021] The cantilever beam piezoelectric vibration energy harvester provided by the present invention includes a piezoelectric vibration energy harvester and a nonlinear force customization device;

[0022] The piezoelectric vibration energy harvester includes a cantilever beam;

[0023] The nonlinear force customization device includes a lifting platform, a roller track, rolling elements, a linear motion mechanism, a horizontal spring, and a preload nut;

[0024] The roller track is formed on one side wall of the lifting platform;

[0025] The linear motion mechanism is disposed at the free end of the cantilever beam, and the linear motion mechanism is provided with a mounting groove extending along the axial direction; the horizontal spring is disposed in the mounting groove.

[0026] The preload nut is disposed in the groove of the mounting groove to limit the horizontal spring in the mounting groove;

[0027] The rolling element is disposed on the outer end face of the preload nut, and the outer wall surface of the rolling element is in close contact with the raceway.

[0028] The design method of the cantilever beam piezoelectric vibration energy harvester provided by the present invention includes the following steps: Step S1: Based on the vibration equation of the cantilever beam, with the goal of optimizing the energy harvesting performance, optimize the design of the resultant force on the cantilever beam in the vibration direction. The optimal form is then determined, thereby identifying the nonlinear force that needs to be customized. Step S2: Based on the nonlinear force Determine the stiffness of the horizontal spring Precompression amount , Bearing radius r; Step S3: According to the above Horizontal spring stiffness Precompression amount The bearing radius r determines the trajectory of the rolling bearing center;

[0029] Step S4: Determine the raceway profile curve based on the center trajectory of the rolling bearing, and machine the raceway according to the raceway profile curve.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] This invention installs a customized nonlinear force mechanism on a linear cantilever beam piezoelectric vibration energy harvester. By customizing the profile curve of the raceway, the reaction force generated when the bearing or roller rolls on the raceway is used to realize the customized nonlinear force requirements in the energy harvester. Attached Figure Description

[0032] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0033] Figure 1 This is a schematic diagram of the structure of the cantilever beam piezoelectric vibration energy harvester in one direction according to the first embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the cantilever beam piezoelectric vibration energy harvester from another direction in the first embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram illustrating the relationship between the bearing center point trajectory and the raceway profile curve in the first embodiment of the present invention;

[0036] Figure 4 This is a flowchart illustrating the steps of the design method for a cantilever beam piezoelectric vibration energy harvester that enables customization of nonlinear forces in the first embodiment of the present invention.

[0037] Figure 5 This is a schematic diagram of the raceway profile curve to be processed in the first embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the structure of the cantilever beam piezoelectric vibration energy harvester in the second embodiment of the present invention;

[0039] Figure 7 This is a schematic diagram of the structure of the cantilever beam piezoelectric vibration energy harvester in the third embodiment of the present invention.

[0040] In the figure: 1 is the substrate; 2 is the cantilever beam; 3 is the piezoelectric sheet; 4 is the mass block; 5 is the rolling bearing; 6 is the raceway whose contour is to be designed; 7 is the linear guide slider mechanism; 8 is the horizontal spring; 9 is the preload nut; 10 is the lifting platform; 11 is the energy storage circuit. Detailed Implementation

[0041] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0042] Figure 1 This is a schematic diagram of the structure of the cantilever beam piezoelectric vibration energy harvester capable of nonlinear force customization in one direction, as shown in the first embodiment of the present invention. Figure 2 This is a schematic diagram of the cantilever beam piezoelectric vibration energy harvester capable of nonlinear force customization in the first embodiment of the present invention, from another direction, as shown below. Figure 1 , Figure 2As shown, the cantilever beam piezoelectric vibration energy harvester with nonlinear force customization provided by the present invention includes a piezoelectric vibration energy harvester and a nonlinear force customization device.

[0043] The nonlinear force customization device includes a lifting platform 10, a raceway 6, rolling elements, a linear motion mechanism, a horizontal spring 8, and a preload nut 9. The linear motion mechanism is mounted on the lifting platform 10, and the preload nut 9 is connected to one end of the linear motion mechanism through the horizontal spring 8, and is used to apply a preload force to the horizontal spring 8, i.e., to adjust the preload force of the horizontal spring.

[0044] The piezoelectric vibration energy harvester includes a column, a mass block 4, a cantilever beam 2, a piezoelectric element 3, and an energy storage circuit 11; the cantilever beam 2 is mounted on the column; the piezoelectric element 3 is mounted on the cantilever beam 2, and the output end of the piezoelectric element 3 is electrically connected to the energy storage circuit 11.

[0045] The raceway 6 is located at the other end of the linear motion mechanism, and the rolling element is located at the free end of the cantilever beam 2. The outer wall surface of the rolling element is in close contact with the raceway 6.

[0046] The rolling element is connected to the free end via the mass block 4, which is used to adjust the first natural frequency of the cantilever beam 2.

[0047] The nonlinear force customization device can be installed on any cantilever piezoelectric vibration energy harvester, thereby enabling it to meet the requirements of nonlinear force customization. The linear motion mechanism 7 can only perform linear motion, ensuring that the horizontal spring 8 will not bend or deform. The preload nut 9 is used to precisely adjust the initial pre-compression of the horizontal spring 8. The lifting platform 10 is used to adjust the height of the raceway 6 so that, in the initial state, the rolling bearing 5 is at the exact center of the raceway 6.

[0048] In this embodiment of the invention, the linear motion mechanism adopts a linear guide rail slider mechanism 8, which includes a linear guide rail and a slider mechanism.

[0049] The slider mechanism is disposed on the upper end surface of the lifting platform 10; the linear guide rail is disposed in the slider mechanism and can slide along the slider mechanism.

[0050] The lifting platform uses a precision fine-tuning displacement table.

[0051] The rolling element is a bearing;

[0052] The cantilever beam 2 is connected to the inner ring of the bearing via the mass block 4; the outer ring of the bearing is tightly fitted to the raceway 6.

[0053] The nonlinear force customization device can be installed on any linear cantilever piezoelectric vibration energy harvester, thereby achieving precise control of the nonlinear force of the system.

[0054] When the base vibrates up and down, the cantilever beam 2 vibrates up and down, causing the bearing 5 to roll on the raceway 6, which in turn causes the raceway 6 to vibrate horizontally. Under the action of the horizontal pre-compression spring 8, the raceway 6 applies a nonlinear reaction force to the bearing 5. By reasonably designing the stiffness and pre-compression of the horizontal spring 8 and the contour shape of the raceway 6, the vertical nonlinear force applied by the raceway to the bearing (i.e., the cantilever beam) can meet customized requirements.

[0055] In this embodiment of the invention, the working principle of the cantilever beam piezoelectric vibration energy harvester capable of customizing nonlinear forces is as follows: The pre-compression force generated by the horizontal spring 8 is transmitted to the cantilever beam 2 through the raceway 6 and the rolling bearing 5, generating a nonlinear compressive force and negative stiffness on the cantilever beam 2. By rationally designing the stiffness and pre-compression of the horizontal spring 8 and the contour shape of the raceway 6, the nonlinear force acting on the cantilever beam 2 can be precisely adjusted.

[0056] Figure 4 This is a flowchart illustrating the steps of the design method for a cantilever beam piezoelectric vibration energy harvester capable of nonlinear force customization in the first embodiment of the present invention. Figure 4 As shown, the design method for a cantilever beam piezoelectric vibration energy harvester with precisely customizable nonlinear forces provided by this invention includes the following steps:

[0057] Step S1: Based on the vibration equation of the cantilever beam, optimize the design of the resultant force on the cantilever beam in the vibration direction with the goal of achieving optimal energy acquisition performance. The optimal form is then determined, thereby identifying the nonlinear force that needs to be customized. Step S2: Based on the nonlinear force Determine the stiffness of the horizontal spring Precompression amount , Bearing radius r; Step S3: According to the above Horizontal spring stiffness Precompression amount The bearing radius r determines the trajectory of the rolling bearing center;

[0058] Step S4: Determine the raceway profile curve based on the center trajectory of the rolling bearing, and machine the raceway according to the raceway profile curve.

[0059] In this embodiment of the invention, in order to meet the customized requirements of the nonlinear force on the cantilever beam 2, it is necessary to determine the stiffness, pre-compression amount of the horizontal spring 8 and the profile shape of the raceway 6.

[0060] Assume that initially, the weight of the cantilever beam 2 and its own stiffness are in static equilibrium. The height of the lifting platform 11 has been adjusted so that the bearing 5 is in the middle position of the raceway 6. Let the bending stiffness of the cantilever beam be denoted as... (That is, the deflection caused by applying a unit force at the bearing), the stiffness of the horizontal spring 8 is The pre-compression amount is (Adjusted by horizontal preload nut 9), the radius of bearing 5 is r, and when bearing 5 rolls along raceway 6, the trajectory of the bearing center point is... As the bearing rolls along the raceway, the trajectory of the bearing's center point... With the raceway Relationships between them Figure 3 As shown. Mathematically, it can be represented as: (1)

[0061] In the formula, yes Upper coordinate point, yes Upper coordinate point, yes Take the derivative with respect to x.

[0062] Assuming that when the cantilever beam 2 vibrates, the center point of the bearing at its end experiences a vibration displacement denoted as x, the total elastic potential energy generated by the horizontal spring 8 at this time can be expressed as (assuming the elastic potential energy is zero in the initial state): (2)

[0063] Therefore, the component of the nonlinear force applied to bearing 5 by raceway 6 in the x-direction can be expressed as: (3)

[0064] set up =0, from equation (2) we can get: (4)

[0065] Therefore, equations (1) and (4) establish the nonlinear force that needs to be customized. With raceway profile curve Inter-relationship. In other words, by customizing the raceway profile curve. It can realize any customizable nonlinear force. Furthermore, the resultant force on the cantilever beam in the x-direction, i.e., the direction of vibration, can be expressed as: (5)

[0066] Therefore, the vibration equation of the cantilever beam can be expressed as: (6)

[0067] In the formula, m is the equivalent mass of the cantilever beam, c is its equivalent damping, and F is the external excitation force. To determine the excitation angular frequency, t represents time, and j represents the imaginary unit. In practical applications, the nonlinear force is often optimized based on equation (6). This allows the cantilever beam to reach its maximum amplitude. In other words, by customizing nonlinear forces... , can make To achieve the optimal form, the cantilever beam amplitude is maximized, resulting in optimal energy harvesting. In practical applications, once the geometric parameters of the cantilever piezoelectric beam are given, its bending stiffness... Given this, the goal of nonlinear force customization is to select a suitable horizontal spring stiffness. and pre-compression amount Contour curves to be processed The nonlinear force generated by it With the bending stiffness of the cantilever beam The resulting resultant force allows the cantilever beam piezoelectric vibration energy harvester to achieve maximum amplitude and widest bandwidth, thus optimizing its energy harvesting performance. Therefore, the nonlinear force... Customization needs to be implemented by considering the vibration characteristics of the cantilever piezoelectric beam itself and the level of environmental excitation. Taking a specific linear cantilever piezoelectric vibration energy harvester as the research object, its nonlinear force is customized according to the above process. Assuming the bending stiffness of the cantilever piezoelectric beam is... The horizontal spring stiffness is 6.8 N / m. The value is 82.1. Nm -1 Spring precompression The radius is taken as 10mm, and the bearing radius is taken as 2mm. Assume the optimized nonlinear force... for: (7)

[0068] Therefore, in the designed vibration energy harvester, the coefficients of its nonlinear force must accurately satisfy equation (7) in order to be considered as realizing the customized requirements of nonlinear force.

[0069] From equation (5), we can see that, It can be represented as: (8)

[0070] The center trajectory of the rolling bearing can be obtained from equation (4). Furthermore, the contour curve to be processed can be obtained, and its shape is shown in Figure 4.

[0071] After machining the raceway and assembling the components, a vibration energy harvester with a nonlinear force type as shown in equation (7) can be obtained, thereby achieving precise customization of the nonlinear force. Following a similar design process, cantilever beam piezoelectric vibration energy harvesters with other forms of nonlinear forces can be obtained.

[0072] Figure 6This is a schematic diagram of the structure of a cantilever beam piezoelectric vibration energy harvester that can realize nonlinear force customization in the second embodiment of the present invention. Those skilled in the art can understand that this embodiment is a variation based on the first embodiment. In this embodiment, the rolling element is disposed at the other end of the linear motion mechanism, the raceway 6 is disposed at the free end of the cantilever beam, and the outer wall surface of the rolling element is closely attached to the raceway 6.

[0073] Figure 7 This is a schematic diagram of the structure of the cantilever beam piezoelectric vibration energy harvester that can realize nonlinear force customization in the third embodiment of the present invention. Those skilled in the art can understand that this embodiment is a variation based on the first embodiment. In this embodiment, the cantilever beam piezoelectric vibration energy harvester provided by the present invention includes a piezoelectric vibration energy harvester and a nonlinear force customization device.

[0074] The piezoelectric vibration energy harvester includes a cantilever beam 2;

[0075] The nonlinear force customization device includes a lifting platform 10, a roller track 6, rolling elements, a linear motion mechanism, a horizontal spring 8, and a preload nut 9;

[0076] The roller track 6 is formed on one side wall of the lifting platform 10;

[0077] The linear motion mechanism is located at the free end of the cantilever beam 2, and the linear motion mechanism is provided with an axially extending mounting groove; the horizontal spring 8 is located in the mounting groove.

[0078] The preload nut 9 is disposed at the opening of the mounting groove to limit the horizontal spring 8 in the mounting groove;

[0079] The rolling element is disposed on the outer end face of the preload nut 9, and the outer wall surface of the rolling element is in close contact with the raceway.

[0080] In this embodiment of the invention, a nonlinear force customization mechanism is installed on a linear cantilever beam piezoelectric vibration energy harvester. By customizing the profile curve of the raceway, the reaction force generated when the bearing or roller rolls on the raceway is used to realize the customization requirements of the nonlinear force in the energy harvester.

[0081] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A design method for a cantilever beam piezoelectric vibration energy harvester, characterized in that, Includes the following steps: Step S1: Based on the vibration equation of the cantilever beam, optimize the design of the resultant force on the cantilever beam in the vibration direction with the goal of achieving optimal energy acquisition performance. The optimal form is then determined, thereby identifying the nonlinear force that needs to be customized. , ; Step S2: Based on the nonlinear force Determine the stiffness of the horizontal spring Precompression amount Bearing radius ; Step S3: According to the above Horizontal spring stiffness Precompression amount and bearing radius Determine the center trajectory of the rolling bearing; Step S4: Determine the raceway profile curve based on the center trajectory of the rolling bearing, and machine the raceway according to the raceway profile curve; the raceway profile curve for: in, yes Upper coordinate point, yes Upper coordinate point, yes right Take the derivative, For its nonlinear force, For the horizontal spring stiffness, This is the pre-compression amount. This refers to the bending stiffness of the cantilever beam.

2. A cantilever beam piezoelectric vibration energy harvester designed using the design method described in claim 1, characterized in that, This includes piezoelectric vibration energy harvesters and customized nonlinear force devices; The piezoelectric vibration energy harvester includes a cantilever beam; The nonlinear force customization device includes a lifting platform, a roller track, rolling elements, a linear motion mechanism, a horizontal spring, and a preload nut; the linear motion mechanism is mounted on the lifting platform, and the preload nut is connected to one end of the linear motion mechanism through the horizontal spring to adjust the preload of the horizontal spring. The outer wall surface of the rolling element is in close contact with the raceway; when the raceway is located at the other end of the linear motion mechanism, the rolling element is located at the free end of the cantilever beam; when the rolling element is located at the other end of the linear motion mechanism, the raceway is located at the free end of the cantilever beam.

3. The cantilever beam piezoelectric vibration energy harvester according to claim 2, characterized in that, It also includes mass blocks; The rolling element is connected to the free end via the mass block, which is used to adjust the first natural frequency of the cantilever beam.

4. The cantilever beam piezoelectric vibration energy harvester according to claim 2, characterized in that, The linear motion mechanism adopts a linear guide rail slider mechanism, which includes a linear guide rail and a slider mechanism. The slider mechanism is disposed on the upper surface of the lifting platform; the linear guide rail is disposed in the slider mechanism and can slide along the slider mechanism.

5. The cantilever beam piezoelectric vibration energy harvester according to claim 3, characterized in that, The rolling element is a bearing; The cantilever beam is connected to the inner ring of the bearing via the mass block; the outer ring of the bearing is tightly fitted to the raceway.

6. The cantilever beam piezoelectric vibration energy harvester according to claim 2, characterized in that, The piezoelectric vibration energy harvester also includes a column, a piezoelectric sheet, and an energy storage circuit. The cantilever beam is mounted on the column; a piezoelectric element is mounted on the cantilever beam, and the output end of the piezoelectric element is electrically connected to the energy storage circuit.

7. The cantilever beam piezoelectric vibration energy harvester according to claim 6, characterized in that, The piezoelectric element is disposed on the upper side, lower side, or both sides of the cantilever beam.

8. The cantilever beam piezoelectric vibration energy harvester according to claim 6, characterized in that, The column is a platform that can be raised and lowered.

9. The cantilever beam piezoelectric vibration energy harvester according to claim 5, characterized in that, The profile curve of the raceway for: in, yes Upper coordinate point, yes Upper coordinate point, yes right Take the derivative, For its nonlinear force, For the horizontal spring stiffness, This is the pre-compression amount. This refers to the bending stiffness of the cantilever beam.

10. A cantilever beam piezoelectric vibration energy harvester designed using the design method described in claim 1, characterized in that, This includes piezoelectric vibration energy harvesters and customized nonlinear force devices; The piezoelectric vibration energy harvester includes a cantilever beam; The nonlinear force customization device includes a lifting platform, a roller track, rolling elements, a linear motion mechanism, a horizontal spring, and a preload nut; The roller track is formed on one side wall of the lifting platform; The linear motion mechanism is disposed at the free end of the cantilever beam, and the linear motion mechanism is provided with a mounting groove extending along the axial direction; the horizontal spring is disposed in the mounting groove. The preload nut is disposed in the groove of the mounting groove to limit the horizontal spring in the mounting groove; The rolling element is disposed on the outer end face of the preload nut, and the outer wall surface of the rolling element is in close contact with the raceway.

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